Bluestone Mines Tasmania JV Pty Ltd - epa.tas.gov.auepa.tas.gov.au/documents/bluestone mines...
Transcript of Bluestone Mines Tasmania JV Pty Ltd - epa.tas.gov.auepa.tas.gov.au/documents/bluestone mines...
Bluestone Mines Tasmania JV Pty Ltd D Dam Tailings Storage Facility
Development Proposal and Environmental Management Plan
March 2015
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | i
Foreword Bluestone Mines Tasmania Joint Venture Pty Ltd proposes a new Tailings Storage Facility
(TSF) called D Dam to support existing operations at Renison Tin Mine, western Tasmania.
The Renison Tin Mine is an operating mine site with three existing TSFs (Dams A, B and C)
located approximately 1 km north of the existing processing plant. This proposal involves the
construction of a new TSF (D Dam) directly adjacent to the existing TSFs to capture tailings
generated by the existing mine over the coming 16 year period.
The addition of D Dam to replace the three existing TSFs which are reaching their design
capacity and will be closed will not change the existing mining or processing operation.
This DPEMP provides a description of the project and local environment, an assessment of
environmental impacts and a description of measures to reduce or avoid those impacts.
The document has been prepared as part of a Development Application to West Coast Council
under the Land Use and Planning Approvals Act 1993. It also comprises
An application to the Environmental Protection Authority (EPA) Board for a permit for a
Level 2C project under the Tasmanian Environmental Management and Pollution Control
Act 1994;
An application to the Commonwealth Department of Environment for approval of a
Controlled Action under the Commonwealth Environmental Protection and Biodiversity
Conservation Act 1999, assessed by the EPA under a Bilateral Agreement; and
An application for permission from the Assessment Committee for Dam Construction
(ACDC), incorporated into the DA process.
ii | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Abbreviations Abbreviation Description
AEP Annual Exceedance Probability
ACDC Assessment Committee for Dam Construction
ANCOLD Australian National Committee on Large Dams
ANZECC Australia and New Zealand Environment Conservation Council
AHD Australian Height Datum
AHT Aboriginal Heritage Tasmania
ALARP As Low As Reasonably Practicable
AMD Acid and Metalliferous Drainage
ARI Average Recurrence Interval
ARMCANZ Agriculture and Resource Management Council of Australia and New Zealand
BMT JV Bluestone Mines Tasmania Joint Venture Pty Ltd
CAR Comprehensive, Adequate and Representative
CEMP Construction Environmental Management Plan
CFT Cassiterite Flotation Tail (oxide tail)
DEHWA Department of Environment, Heritage, Water and the Arts
DEPHA Department of Parks, Heritage and the Arts
DIER Department of Infrastructure Energy Resources
DPEMP Development Proposal and Environmental Management Plan
DPIPWE Department of Primary Industries Parks Water and Environment
DSC Dam Safety Committee
DTAE Department of Tourism Arts and Environment
EMPCA Environmental Management and Pollution Control Act 1994
EPA Environment Protection Authority
EPBCA Environment Protection and Biodiversity Conservation Act 1999
EPN Environmental Protection Notice
FPA Forest Practices Authority
FSC Final Sulphide Concentrate
FT Forestry Tasmania
GHG Greenhouse Gas
HazID Hazard Identification
HSMP Health and Safety Management Plan
HST High Sulphur Tailings
LIST Land Information System Tasmania`
LST Low Sulphur Tailings
LUPAA Land Use Planning and Approvals Act 1993
MDE Maximum Design Earthquake
ML Megalitre
Mt Million Tonnes
MRDA Minerals Resource Development Act 1995
MRT Mineral Resources Tasmania
MSDS Material Safety Data Sheet
NAPP Net Acid Producing Potential
NAF Non Acid Forming
NAG Net Acid Generation
NEPM National Environmental Protection Measure
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | iii
NGS National Greenhouse Strategy
NH3 Ammonia
NoI Notice of Intent
NVA Natural Values Atlas
NWI National Wilderness Inventory
OBE Operating Basis Earthquake
OEMP Operational Environmental Management Plan
PAF Potential Acid Forming
PAR Population at Risk
PMP Project Management Plan
RL Reduced Level
SLT Slime Tails
TALSC Tasmanian Aboriginal Land and Sea Council
TASI Tasmanian Aboriginal Site Index
TSF Tailings Storage Facility
TSS Total Suspended Solids
WCC West Coast Council
WTP Wastewater Treatment Plant
iv | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Executive Summary Introduction
Bluestone Mines Tasmania Joint Venture Pty Ltd (BMT JV) proposes a new Tailings Storage
Facility (TSF) called D Dam to support existing operations at Renison Tin Mine, western
Tasmania.
The Renison Tin Mine is an operating mine site that directly employs in excess of three hundred
workers on the West coast of Tasmania and produces in excess of 7000 Tonnes of Tin in
concentrate per annum (valued at >$168M). The operation consists of an Underground Mine,
Processing facility and three existing TSFs (Dams A, B and C) located approximately 1 km north
of the existing processing plant. The Operation has successfully managed TSF’s over some 50
years of operation and now requires a new TSF in order to continue operations.
This proposal involves the construction of a new TSF (D Dam) directly adjacent to the existing
TSFs to capture tailings generated by the existing mine over the coming 16 year period.
The addition of D Dam will replace the existing TSFs which are reaching their design capacity.
The new D Dam will not change the existing mining or processing operation.
This DPEMP provides a description of the project and local environment, an assessment of
environmental impacts and a description of measures to reduce or avoid those impacts.
The assessment is carried out under the Tasmanian Environmental Management and Pollution
Control Act 1994, the Land Use Planning and Approvals Act 1993 and the Commonwealth
Environmental Protection and Biodiversity Conservation Act 1999.
The Tasmanian EPA set Project Specific Guidelines (December 2012) defining the scope of
assessment which includes the following key issues:
1 Potential for impacts on threatened flora and/or ecological communities due to
vegetation clearing.
2 Potential for impacts on threatened fauna and/or their habitats due to vegetation
clearing.
3 Potential for impacts on catchment surface and ground water quality during construction
and operation of the TSF, and ongoing management of the TSF for seepage and AMD.’
The Project
D Dam is planned as a traditional earth dam to be built over a period of 2 years and will be
constructed to an acceptable standard of dam safety and stability built to ANCOLD guidelines
and subject to approval from the Assessment Committee for Dam Construction (ACDC) in
Tasmania. Development will involve site clearance, the creation of borrow areas to source
suitable materials for use in the construction of the embankment.
In accordance with current projected Mine production schedules ,(760,00 tonnes per annum,
based on normal Renison mining operations), D Dam will be built in stages, and on completion
will have a footprint of approximately 48.9 hectares (ha) and a maximum storage capacity of
approximately 6.5 Mm3.
In a proactive move designed to manage existing surface waste rock stockpiles as well as some
‘legacy material’, it is proposed to include existing waste rock and legacy material within the D
Dam embankment during construction. Existing waste rock from the mine site will be
categorised, treated with lime to neutralise any AMD potential and encapsulated within a 1 m
think clay lined zone before being inundated by water in the lower part of the dam wall
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | v
embankment. This approach addresses an existing site issue with waste rock storage and
reduces the requirement for new material to be sourced for dam wall construction.
Tailings generated from the processing of Ore at Renison can be rich in metals and potentially
form acid on contact with oxygen. The D Dam proposal involves tailings deposition into the new
TSF in a manner that places low sulphide tailings against the main embankment and ensuring
that all high sulphide tailings (HST) are stored at a lower level under permanent water cover to
avoid oxidisation and acid generation and prevents acid formation and limits release of
contaminants. D Dam will include a permanent discharge to the Ring River, replacing existing
discharges from A, B and C Dam. Small amounts of seepage from D Dam are expected but
existing problem seepage from A, B and C Dam will reduced through partial capture and
treatment with the D Dam decant water.
D Dam will be constructed over a two year period commencing during the summer of 2016.
Existing Environment
The D Dam footprint has previously been subject to selective logging and mining related
activities. The key environmental values identified include:
The surface waters of Lake Pieman and Ring River (flooded arm of Lake Pieman).
The native vegetation communities within the D Dam footprint including small patches of
one threatened wetland vegetation community.
Potential habitat for a range of native fauna species.
Presence of threatened species: Spotted-tailed quoll, Tasmanian devil, azure kingfisher
and wedge-tailed eagle, and potential presence of grey goshawk, Tasmanian masked owl
and white–bellied sea eagle
Presence of shallow groundwater aquifers not used for water extraction.
Examples of the Central Highlands Cainozoic Glacial Area geoconservation site.
No European or Aboriginal Heritage features were identified within the D Dam footprint.
Potential Impacts and Mitigation Summary
The key impacts anticipated because of the development and their main mitigation strategies
are summarised below, with the detailed information contained within the DPEMP.
vi | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Topic Impact and Mitigation
Surface
Water
Construction impacts on water quality could occur from silty runoff, grouting or
possible spills. Surface water impacts during construction will be mitigated by a range
of hazardous materials controls, sediment controls and spill response measures.
Operational impacts may occur from seepage and discharge of tailings effluent to the
Ring River and Lake Pieman. Impacts from tailings effluent discharge will be
controlled by limiting tailings acid formation (pre-dominantly by tailings deposition
approach) and have been shown to be within acceptable limits by modelling.
Seepage will be controlled through dam design, tailings management and grouting of
the dam wall.
Minor hydrology changes are anticipated, which are not expected to affect overall
flows to Lake Pieman.
Groundwater Potential groundwater contamination from grouting, spills and releases during
construction will be managed through standard spill controls, careful and fully
qualified grouting operations and spill response measures.
Borrow excavation may alter local groundwater flow, however the borrow areas will
be shallow and sited on rises which will limit the potential for groundwater impacts.
Key potential groundwater impacts during operation relate to potential changes in
flow associated with the TSF and seepage during operation.
Groundwater quality will be protected by avoiding AMD formation in the TSF
(predominantly through the tailings deposition strategy and water cover over HST).
The grout curtain, low permeability of the tailings and patching of high permeability
areas (and decant pond) with clay will limit seepage.
Biodiversity Permanent loss of 36.5 ha of native communities including one threatened
community (of degraded quality) and habitat for threatened fauna species. No
threatened flora were identified within the footprint.
The potential loss of threatened fauna habitat will be mitigated by avoiding breeding
seasons for most species (where possible), revegetating borrow areas and
undertaking pre-clearance surveys for species, particularly where works cannot be
contained outside of breeding seasons.
Potential incursion of weeds and other pathogens into adjacent vegetation
communities will be controlled by implementation of a Weed Management and
Hygiene Plan.
Injury or death of Tasmanian devils due to impacts with construction vehicles will be
controlled by working hour limits and speed restrictions.
Air Quality Minor potential for dust generation during construction and operation to be controlled
by prevention, monitoring and targeted dust suppression.
Noise Noise impacts associated with the TSF construction and operation are expected to
be negligible, particularly through control of operational hours, limits on road traffic
speeds and the significant distance to the nearest residence. If blasting is required to
extract construction materials, necessary permits would be sought.
Solid and
Controlled
Construction will generate vegetation waste, soil and small amounts of general
waste. Effective storage and reuse of vegetation waste (through mulching) and soil
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | vii
Topic Impact and Mitigation
Waste (storage and reuse) will be employed where possible. Other wastes will be stored in
suitable locations and removed from site by licenced contractors.
Dangerous
Goods
Potential use of explosives, fuels, lubricants and hydrated lime will be stored in
accordance with relevant Australian Standards in most cases within existing facilities
at the Processing Plant site.
Geo-
conservation
Impact on geo-conservation values associated with the Central Highlands Cainozoic
Glacial Area due to excavation of borrow areas are expected and will be mitigated by
recording and documentation of deposits.
Greenhouse
Gas
Minor greenhouse gas emissions are expected during construction and operation and
will be mitigated as much as possible by the use of well-maintained machinery and
vehicles.
Heritage Aboriginal and European heritage surveys indicated no sites of significance. However
if any heritage features are unearthed during construction works will cease and the
relevant authorities will be notified.
Land Use The proposed development complies with the West Coast Interim Planning Scheme
2013 and associated regulations.
Visual Visual impacts from public view points are expected to be minor. The embankment
and borrow areas may be visible from some locations on the Ring River and Lake
Pieman.
Socio-
economic
D Dam will allow the ongoing operation of the Renison Tin Operation, supporting
local communities through continued direct and indirect employment and demand for
local businesses.
Health and
Safety
A construction health and safety management plan will be prepared. Health and
safety management measures associated with the operation of the dam will be
included in operational management.
Infrastructure
and Off-site
Facilities
There are no significant impacts anticipated in relation to off-site infrastructure and
facilities, such as roads, electricity supply and water supply.
Environmental Management Systems
A Construction EMP will be prepared prior to commencement of the construction phase and
operational requirements for D Dam will be incorporated into the existing site EMP.
Monitoring and Review
To monitor the accuracy of predicted environmental impacts and measure the success of
proposed mitigation measures, a monitoring program will be established. Detailed monitoring
plans for each discipline are provided in Section 4 and summarised in Section 7, with key
monitoring to include:
Pre-construction fauna surveys;
Groundwater monitoring program;
Point source monitoring of TSF discharges;
viii | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Receiving water monitoring to supplement the existing program; and
Post-commissioning review.
Decommissioning and Rehabilitation
The proposed final closure design for D Dam is full water cover over the high sulphide tailings
and a combination water and soil cover over the low sulphide tailings. The dam has however
been designed using downstream construction, allowing the use of permanent flooding as an
alternative closure option if required.
Borrow areas will be rehabilitated at the end of use.
Commitments
A series of key commitments made through this document is listed in Section 9.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | ix
Table of Contents 1. Introduction..................................................................................................................................... 1
1.1 Background .......................................................................................................................... 1
1.2 Location ............................................................................................................................... 1
1.3 Need for the Project ............................................................................................................. 1
1.4 Proponent ............................................................................................................................ 1
1.5 Proposal Status .................................................................................................................... 2
1.6 Public and Stakeholder Consultation ................................................................................... 2
1.7 Legislative Context ............................................................................................................... 3
2. Proposal Description ...................................................................................................................... 6
2.1 Existing Tailings Storage at Renison ................................................................................... 6
2.2 D Dam Design ...................................................................................................................... 9
2.3 Materials ............................................................................................................................ 19
2.4 PAF Waste Rock In D Dam ............................................................................................... 22
2.5 Operation ........................................................................................................................... 25
2.6 Water Balance ................................................................................................................... 28
2.7 Wastewater Flows .............................................................................................................. 30
2.8 Plant Requirements ........................................................................................................... 32
2.9 Site Services and Offsite Infrastructure ............................................................................. 32
2.10 Construction ....................................................................................................................... 32
2.11 Technical and Management Alternatives........................................................................... 35
3. The Existing Environment ............................................................................................................ 40
3.1 Planning Aspects ............................................................................................................... 40
3.2 European Heritage ............................................................................................................. 41
3.3 Aboriginal Heritage ............................................................................................................ 42
3.4 Environmental Aspects ...................................................................................................... 42
3.5 Terrestrial Ecology ............................................................................................................. 58
3.6 Aquatic Ecology ................................................................................................................. 69
3.7 Natural Hazards and Processes ........................................................................................ 73
3.8 Socio-economic Aspects ................................................................................................... 73
4. Potential Effects and Their Management ..................................................................................... 75
4.1 Surface Water .................................................................................................................... 75
4.2 Groundwater ...................................................................................................................... 85
4.3 Biodiversity and Natural Values ......................................................................................... 92
4.4 Air Emissions ................................................................................................................... 106
4.5 Noise Emissions .............................................................................................................. 108
4.6 Solid and Controlled Waste Management ....................................................................... 110
4.7 Dangerous Goods ............................................................................................................ 112
4.8 Geo-conservation ............................................................................................................. 113
x | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.9 Greenhouse Gases and Ozone Depleting Substances ................................................... 114
4.10 Heritage ........................................................................................................................... 115
4.11 Land Use and Development ............................................................................................ 117
4.12 Visual Effects ................................................................................................................... 119
4.13 Socio-economic Issues .................................................................................................... 123
4.14 Health, Safety and Environmental Hazard Analysis ........................................................ 124
4.15 Infrastructure and Off-site Ancillary Facilities .................................................................. 128
4.16 Cumulative and Interactive Effects .................................................................................. 129
5. EPBC Assessment ..................................................................................................................... 130
5.1 Background ...................................................................................................................... 130
5.2 General Information ......................................................................................................... 130
5.3 Relevant Impacts ............................................................................................................. 130
5.4 Proposed Safeguards and Mitigation Measures .............................................................. 131
5.5 Environmental Record of Proponent ................................................................................ 134
5.6 Information Sources ......................................................................................................... 134
6. Environmental Management Systems ....................................................................................... 135
6.1 Management System Description .................................................................................... 135
6.2 Construction Environmental Management Plan (CEMP) ................................................ 135
6.3 Operational Environmental Management Plan ................................................................ 138
6.4 Management Commitments ............................................................................................. 138
7. Monitoring and Review ............................................................................................................... 139
7.1 Pre clearance surveys ..................................................................................................... 139
7.2 Construction Surveillance ................................................................................................ 139
7.3 Operational Monitoring..................................................................................................... 139
7.4 Post Commissioning Review ........................................................................................... 141
7.5 Management Commitments ............................................................................................. 141
8. Preliminary Decommissioning and Rehabilitation Plan ............................................................. 142
8.1 TSF Closure method ........................................................................................................ 142
8.2 Rehabilitation ................................................................................................................... 144
8.3 Post Closure Monitoring and Maintenance ...................................................................... 145
8.4 Stakeholder Consultation ................................................................................................. 146
8.5 Management Commitments ............................................................................................. 146
9. Commitments ............................................................................................................................. 147
10. Conclusion.................................................................................................................................. 151
11. References ................................................................................................................................. 152
Table index Table 2-1 Average Tailings Discharge and Seepage Quality (2007 to 2014) ..................................... 8
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | xi
Table 2-2 D Dam Levels ...................................................................................................................... 9
Table 2-3 Embankment geometry ...................................................................................................... 10
Table 2-4 Embankment internal zoning ............................................................................................. 11
Table 2-5 Permeability of Embankment Materials ............................................................................. 16
Table 2-6 Construction Material Volumes and Sources .................................................................... 20
Table 2-7 Borrow Areas ..................................................................................................................... 21
Table 2-8 Waste Rock Sources ......................................................................................................... 23
Table 2-9 Required Saturation of Cover to Achieve 98% Reduction in ASGR .................................. 24
Table 2-10 Composition of the HST and LST Streams ....................................................................... 25
Table 2-11 Predicted TSF Discharges ................................................................................................. 31
Table 2-12 Stage 1 Indicative Construction Programme ..................................................................... 33
Table 2-13 TD Discharge Options Assessment Summary .................................................................. 39
Table 3-1 Climate Data – Rainfall (Renison 097021) ........................................................................ 43
Table 3-2 Evaporation ........................................................................................................................ 44
Table 3-3 Temperature (Strahan Aerodrome 097072) ...................................................................... 44
Table 3-4 Ambient Water Quality Results .......................................................................................... 50
Table 3-5 Water Quality Trigger Values 80 Percentile Ambient Data................................................ 52
Table 3-6 Groundwater Quality Test Results (Coffey, 2013) ............................................................. 57
Table 3-7 Listed Fauna Known or Predicted Within 5 km of the Project Footprint ............................ 60
Table 3-8 Non-threatened Native Fauna Recorded During Survey ................................................... 66
Table 3-9 Listed Aquatic Fauna Known or Predicted Within 5 km of the Project Footprint ............... 69
Table 3-10 AUSRIVAS Data for the Ring and Argent Rivers 1994-97 ................................................ 70
Table 3-11 AUSRIVAS results from invertebrate surveys 2011-2014 ................................................. 71
Table 3-12 CFEV Aquatic Ecology Indices for watercourses in the project area ................................ 73
Table 4-1 Monitoring .......................................................................................................................... 82
Table 4-2 Additional Monitoring Points .............................................................................................. 83
Table 4-3 Estimated Seepage from Proposed Design ...................................................................... 87
Table 4-4 Estimated Annual Contaminant Loadings ......................................................................... 88
Table 4-5 Groundwater Monitoring Boreholes ................................................................................... 90
Table 4-6 Estimated Extent of Vegetation Clearance for Project ...................................................... 93
Table 4-7 D Dam Construction (and borrow area) Waste Estimate ................................................ 110
Table 4-8 Planning Policy Compliance Summary ............................................................................ 118
Table 5-1 Potential Impacts on EPBC Listed Threatened Species ................................................. 132
Table 7-1 Summary of Monitoring Programme ................................................................................ 140
Table 8-1 Summary of Post Closure Monitoring .............................................................................. 145
xii | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | xiii
Figure index
Figure 1-1 Site Location ....................................................................................................................... 5
Figure 2-1 D Dam Project Layout ....................................................................................................... 12
Figure 2-2 Cross Sections .................................................................................................................. 13
Figure 2-3 Embankment at Stage 1 and Final level ........................................................................... 14
Figure 2-4 Seepage Control Features ................................................................................................ 15
Figure 2-5 Drainage Features ............................................................................................................ 15
Figure 2-6 Tailings Geochemical Classification ................................................................................. 26
Figure 2-7 Illustrative Cross Section on Closure ................................................................................ 28
Figure 2-8 D-Dam Water Balance ...................................................................................................... 29
Figure 3-1 Mean Rainfall Data Renison Bell Gauge 1911 to 2013 (BOM) ........................................ 43
Figure 3-2 Average Annual Wind Data at 3 pm for Strahan Aerodrome (097072) ............................. 45
Figure 3-3 Hydrology and Water Sampling Locations......................................................................... 53
Figure 3-4 Vegetation Communities in the Project Footprint ............................................................. 67
Figure 3-5 Fauna Habitat Values in the Project Footprint .................................................................. 68
Figure 4-1 Conceptual Hydrogeological Model (from Appendix G) ................................................... 86
Figure 4-2 Example Seepage Section: D2 (Main) Embankment ........................................................ 87
Figure 4-3 View Towards D Dam from Processing Plant Entrance ................................................. 120
Figure 6-1 CEMP Organisation Chart .............................................................................................. 136
xiv | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Appendices Appendix A – Project Specific Guidelines
Appendix B - Planning Report
Appendix C – European Heritage Report
Appendix D – Aboriginal Heritage Survey
Appendix E – Geomorphology Report
Appendix F – D Dam Water Balance
Appendix G – Hydrogeology Report
Appendix H – Geochemistry
Appendix I – Ecological Assessment
Appendix J – Weed Management and Hygiene Plan
Appendix K – Natural Values Atlas
Appendix L – Protected Matters Search Tool
Appendix M – Receiving Environment Assessment
Appendix N - Aquatic ecology survey results
Appendix O – Pre-construction Design Report
Appendix P - Risk Assessment
Appendix Q – Bluestone Mines Tasmania JV Pty Ltd Environmental Policy Statement 2014
Appendix R – Assumptions and Limitations
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 1
1. Introduction 1.1 Background
Bluestone Mines Tasmania Joint Venture Pty Ltd (BMT JV) proposes to construct the D
Dam Tailings Storage Facility (TSF) to support the existing activities at the Renison Bell
Tin Mine, west of Rosebery, in western Tasmania (see Figure 1-1, page 5).
Following an extended hiatus, mining resumed at Renison in July 2008 with ore initially
being sourced from the Mt Bischoff mine but latterly from the underground workings at
Renison. Since 2008, tailings generated by the nearby Renison Processing Plant have
been stored in one of three existing TSFs, first C Dam and then, since an embankment lift
in 2012, A and B Dams.
This document is subject to assumptions and limitations as described in Appendix R.
1.2 Location
D Dam is to be constructed at the Renison Bell Tin Mine, downstream of the three
existing TSFs, 1.5 km north of the Renison Processing Plant and approximately 10 km
from Rosebery (see Figure 1-1, page 5).
Renison Bell is an underground mine with workings extending south from the main portal
and process plant area. The underground workings are more than 1.5 km from the D
Dam footprint at their closest point.
The Emu Bay railway line lies approximately 100 m from the eastern edge of the TSF.
1.3 Need for the Project
D Dam is required to provide future capacity for the storage of tailings from ore
processing at the Renison Bell Tin Mine. The existing TSFs (see Section 2.1.1) have
capacity to receive tailings at current rates until 2018 after which new storage will be
required.
It is also likely that D Dam will become an important part of the potential reprocessing of
tailings from existing dams at Renison (Rentails Project) in the future, although this is not
part of this DPEMP. The consequences of not proceeding with D Dam would be the
cessation of mining activities at Renison and the closure of the mine.
1.4 Proponent
The BMT JV operates as a joint venture between Metals X Ltd and YT Parksong Australia
Holding Pty Ltd. BMT JV is the owner of the Renison Bell Tin Mine.
The contact person for this project is:
Karen Pascoe
Environment Coordinator
Bluestone Mines Tasmania Joint Venture Pty Ltd
PO Box 20
Zeehan TAS 7469
ABN: 35 141 265 974
Phone: +61 3 6473 2722
2 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
BMT JV registered company address is:
Murchison Highway
Renison Bell
Zeehan 7469
Tasmania
GHD Pty Ltd has provided engineering, environmental and planning assistance to BMT
JV, in preparing this DPEMP on behalf of the proponent. The GHD contact for this project
is:
Hugh Kerr
Environmental Scientist
GHD Pty Ltd
2 Salamanca Square
Hobart, TAS, 7000
Phone: +61 3 62100 664
ABN: 39 008 488 373
There are no known proceedings against the proponent and they are considered capable
of meeting the financial and resource implications of constructing D Dam.
1.5 Proposal Status
In 2008 the proposal was submitted to the Board of Environmental Management and
Pollution Control of the Department of Environment, Parks, Heritage and the Arts
(DEPHA) (which is now the Board of the Environment Protection Authority (EPA)) in the
form of a Notice of Intent. The Board determined that the proposal would be assessed as
a Level 2B activity under the Environmental Management Pollution Control Act 1994
(EMPCA) and Project Specific Guidelines were issued.
Subsequent to that decision, ecological studies revealed the potential for significant
impact under the Commonwealth Environment Protection and Biodiversity Conservation
Act 1999 (EPBCA) and a referral was submitted to the Department of Sustainability,
Environment, Water, Population and Community (DSEWPaC) (now Department of the
Environment) in July 2012. As a result, the Project was determined as a ‘Controlled
Action’.
A new Notice of Intent (NOI) was then submitted to the Board of the Environment
Protection Authority (EPA) and the project was determined as a Level 2C activity under
the Environmental Management Pollution Control Act 1994 (EMPCA) , incorporating an
assessment of impacts on Matters of National Environmental Significance (MNES) under
the Bilateral Agreement.
Project Specific Guidelines for the DPEMP were issued in December 2012 (see Appendix
A).
1.6 Public and Stakeholder Consultation
BMT JV has consulted the West Coast Council in relation to D Dam.
The final DPEMP and associated Development Application (DA) will be presented for
public display and if necessary BMT JV will to respond to public comments in a
Supplement to the DPEMP.
Future stakeholder consultation will be undertaken in relation to mine closure and
rehabilitation as described in Section 8.4.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 3
1.7 Legislative Context
D Dam will also have to comply with a broad range of environmental and planning
legislation, guidelines, standards and policies as outlined in the relevant sections. Key
legislative requirements are described below.
1.7.1 Environmental Management Pollution Control Act 1994 (EMPCA)
As a Level 2 activity, the proposal requires approval from the Board of the Environment
Protection Authority (EPA). Approval is also required from West Coast Council under the Land Use Planning and Approvals Act 1993 (LUPAA). These two tiers of assessment and
approval are undertaken concurrently and relate to different aspects of the project. The
Board assessment is in accordance with the Environmental Impact Assessment
Principles under EMPCA, while the Council’s assessment is in accordance with the land
use planning considerations under the West Coast Interim Planning Scheme 2013.
Council is not required to assess any matter already addressed in the Board's
assessment.
1.7.2 Environmental Protection and Biodiversity Conservation 1999 (EPBCA)
As a Controlled Action due to the potential presence of fauna species listed as Matters of
National Environmental Significance (MNES) under the Commonwealth Environment
Protection and Biodiversity Conservation Act 1999, the Project requires approval from the
Commonwealth Department of Environment. This assessment is undertaken under a
Bilateral Agreement and is therefore subject to relevant Commonwealth assessment
guidance. Section 5 presents a summary of Impacts on MNES.
1.7.3 Dam Safety Legislation
As this project relates to dam construction, the Assessment Committee for Dam
Construction (ACDC) will be involved. Any permit conditions associated with the ACDC
process will be included in any permit issued by West Coast Council.
The primary regulatory documentation, upon which the TSF feasibility design is based on, are the Tasmanian State Government Water Management Act 1999 and Water
Management (Safety of Dams) Regulations 2003, which are based on Australian National
Committee on Large Dams (ANCOLD) and New South Wales Dam Safety Committee
(DSC) Guidelines.
1.7.4 Land Use Planning and Approvals Act 1993
The Land Use Planning and Approvals Act 1993 (LUPAA) is the principle land use
planning legislative instrument under the Resource Management and Planning System
(RMPS) of Tasmania. The aim of the RMPS is to achieve sustainable outcomes from the
use and development of the State’s natural and physical resources.
The West Coast Interim Planning Scheme 2013 regulates local land use and
development based on the objectives of the RMPS described in Schedule 1 of LUPAA.
The relevant provisions of the Scheme are outlined below, and addressed in the planning
assessment detailed in Appendix B.
Approval for the Project will be sought through LUPAA by a Development Application
submission to West Coast Council.
4 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
1.7.5 State Policy on Water Quality Management 1997
The key policy document describing the management of liquid waste in Tasmania is the
State Policy on Water Quality Management 1997 (SPWQM). The purpose of this policy is
to protect or enhance Tasmania’s water resources while allowing for sustainable
development. All liquid waste discharges from the project must comply with the objectives
of the Policy. The SPWQM is described more fully in Section 4.1.1.
368,000
368,000
369,000
369,000
370,000
370,000
371,000
371,000
372,000
372,000
373,000
373,000
374,000
374,000
375,000
375,000
376,000
376,000
377,000
377,000
378,000
378,000
5,371
,000
5,371
,000
5,372
,000
5,372
,000
5,373
,000
5,373
,000
5,374
,000
5,374
,000
5,375
,000
5,375
,000
5,376
,000
5,376
,000
5,377
,000
5,377
,000
N:\AU\Hobart\Projects\32\16878\GIS\Maps\3216878_1-1_Site_Locality_RevD.mxd
© 2015. Whilst every care has been taken to prepare this map, GHD (and DPIPWE TASMAP and MRT) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason.
Figure 1-1
Job NumberRevision E
32-16878
Map Projection: Transverse MercatorHorizontal Datum: Geocentric Datum of Australia 1994
Grid: Map Grid of Australia, Zone 55
Date 03 Mar 2015
BMT JV Pty LtdRenision Bell, Tailing Storage FacilityDPEMP
Location Map
Data source: GHD proposed D-Dam embankment extents 2011, Bluestone Mines Tasmania dam extents 2011, DPIPWE TASMAP 1:25,000 topographic map 2008, Mineral Resources Tasmania mine lease boundary 2011. Created by: AH Edited by: jtoregan, jpulford & dtickner
2 Salamanca Square Hobart TAS 7000 Australia T 61 3 6210 0600 F 61 3 6210 0601 E [email protected] W www.ghd.com
ROSEBERY
ZEEHAN(16 km)
MURCHISON HWY
0 250 500 750 1,000m
Scale at A4 - 1:40 000 Mill site
Proposed Borrow Area
Existing dam
Mine lease boundary
Tailings Pipeline
QUEENSTOWNHOBART
BURNIEDEVONPORT
LAUNCESTON
LOCATION MAP
Survey Area
SOUTHERNOCEAN Tasman
Sea
Bass Strait
Proposed Dam Outline
6 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
2. Proposal Description 2.1 Existing Tailings Storage at Renison
2.1.1 TSF History
The three existing TSFs at the Renison Bell Tin Mine, A, B and C Dam, are in an area
originally known as Button Grass Flats approximately 1 km north of the processing plant
(see Figure 2-1, page 12). All three are zoned earthfill embankments constructed
primarily of weathered argillite (a metamorphosed siltstone) with the more highly
weathered material being used on the upstream side. C Dam comprises three separate
embankments constructed initially as conventional earthfill dams.
The history of the site can be summarised by the following timeline:
1968 to 1975 A, B and C Dams constructed, A and B Dams raised in four lifts
to a crest level of 185 m Above Height Datum (AHD).
1977 A stabilising berm was added at the base of the B dam to
improve embankment stability.
1999 Crest of B Dam was raised by upstream construction to a crest
level of 187.5 m AHD as part of the TSF closure plan.
1999 Crests of A and B Dams raised by upstream construction (to
crest levels of 188 and 187.5 m AHD respectively) as part of
TSF closure plan. A and B dams were subsequently closed.
1990 -2012 C Dam crest raised from 182.5 m AHD in a series of 2 m high
upstream construction lifts to the current crest height of 194.5 m
AHD.
2008 to 2011 Mount Bischoff ore processed at Renison and tailings deposited
to C Dam.
2012 Closure of C Dam with soil water cover.
2012 A and B Dam reopened with lifts to 190 m and 189.5 m AHD
respectively.
2.1.2 Previous Tailings Management Regimes
Prior to 1990 tailings were discharged to the TSFs via a single pipe, allowing tailings
oxidation to take place and leading to AMD generation.
Closure of A and B Dam in 1999, upstream construction and implementation of a twin-line
tailings discharge pipe segregating High Sulphide Tailings (HST) and Low Sulphide
Tailings (LST) served to reduce AMD. Nonetheless, historical seepage from the three
dams continues which have elevated acidity and metals, consistent with AMD (see
Section 2.1.4).
2.1.3 Historical Tailings Decant
The current TSF discharge arrangements can be summarised as follows:
A and B Dams are active, receiving processed tails from the processing plant and
discharge decant water via discharge point TB (see Figure 3-3) into the Ring River.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 7
C Dam is in the process of being closed and its discharge into the Argent River via
point TC will cease, apart from a residual overflow, following closure.
Data from water quality monitoring between 2007 and 2014 at the two main discharges
from existing TSFs (B Dam and C Dam) are shown in Table 2-1.
As opposed to seepage, which relates to longer term processes within the TSFs, the
quality of decant water relates more directly to the material currently being processed by
the plant. Although there has been historical variation in the quality of decant, there has
been no clear trend over the period for which monitoring data exists.
2.1.4 Historic Seepage
Due to historical management practices, water with elevated acidity and contaminants
such as metals and sulphate consistent with Acid Mine Drainage (AMD) has been
recorded seeping from A, B and C Dam at seepage discharge points S1 and S2 (sample
location points on Figure 3-3). Recent monitored water quality from these seepages is
shown in Table 2-1. The trends in quality for this seepage are discussed in Section 3.4.5.
Seepage from A, B and C Dams (eastern half or ‘C1’) is currently directed through a V-
notch weir, before discharging at point ‘S2’ to Lake Pieman. Additional seepage from the
eastern half of C Dam is directed through a V-notch weir before discharging to Argent
River at discharge point ‘S1’, locations of which are shown on Figure 3-3.
8 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Table 2-1 Average Tailings Discharge and Seepage Quality (2007 to 2014)
Parameter TB TC
Ave 20th %ile
80th %ile
Max Min Ave 20th %ile
80th %ile
Max Min
pH 5.94 5.74 6.07 8.39 3.96 5.71 5.70 6.20 9.37 3.10
Cond (S/cm 591.43 225.19 786.61 3080.00 2.75 1939.67 1618.82 2247.19 3070.00 413.00
TSS(mg/l) 4.46 1.92 6.10 28.00 0.00 18.69 17.96 19.43 148.00 2.00
SO4(mg/l) 356.02 73.62 665.97 2220.00 5.20 1230.18 942.26 1475.50 2230.00 2.23
F (mg/l) 3.93 2.31 5.73 15.00 0.84 9.58 9.75 10.63 15.30 2.70
N (T) (mg/l) 1.14 0.09 2.40 5.00 0.04 2.34 1.08 3.66 7.00 0.05
P (T) (mg/l) 0.25 0.01 0.60 1.90 0.00 0.86 0.41 1.01 4.70 0.08
Fe (D) (mg/l) 0.241 0.045 0.327 3.890 0.020 6.040 3.613 5.488 49.500 0.034
Zn (D) (mg/l) 0.020 0.012 0.026 0.161 0.001 0.059 0.041 0.072 3.010 0.001
Al (T) (mg/l) 0.590 0.312 0.697 3.000 0.040 1.188 0.740 1.218 4.700 0.337
As (T) (mg/l) 0.006 0.001 0.009 0.029 0.001 0.048 0.030 0.065 0.379 0.010
Cu (T) (mg/l) 0.015 0.006 0.024 0.064 0.002 0.001 0.000 0.001 0.023 0.000
Fe (T) (mg/l) 0.32 0.10 0.42 1.64 0.04 0.02 0.01 0.02 0.00 0.00
Mn (T) (mg/l) 14.14 4.80 22.48 84.70 0.02 0.08 0.02 0.16 0.12 0.00
Ni (T) (mg/l) 0.066 0.005 0.055 0.420 0.001 6.201 5.248 7.288 35.300 2.120
Pb (T) (mg/l) 0.006 0.001 0.008 0.047 0.001 13.671 12.508 14.730 30.800 2.890
Zn (T) (mg/l) 0.029 0.018 0.046 0.198 0.001 0.016 0.010 0.016 0.055 0.006
Parameter S1 S2
Ave 20th %ile
80th %ile
Max Min Ave 20th %ile
80th %ile
Max Min
pH 4.48 3.76 5.09 6.10 3.09 3.19 3.15 3.19 3.84 2.88
Cond (S/cm 2489.64 2339.9 2620.5 3620.0 2.92 1606.3 1596.94 1639.98 2267.0 3.03
TSS(mg/l) 7.91 3.25 7.72 45.00 0.80 7.25 5.14 7.09 315.00 0.00
SO4(mg/l) 1649.50 1585.6 1841.3 2740.0 0.00 929.04 875.02 944.57 2150.0 367.00
F (mg/l) 2.99 2.11 3.55 18.60 0.66 1.57 1.39 1.76 11.90 0.68
N (T) (mg/l) 0.75 0.56 0.97 1.50 0.05 0.41 0.35 0.47 0.70 0.05
P (T) (mg/l) 0.02 0.01 0.02 0.09 0.00 0.03 0.01 0.03 0.31 0.00
Fe (D) (mg/l) 85.221 53.303 118.68 268.0 3.100 25.981 15.611 33.296 72.900 5.400
Zn (D) (mg/l) 7.736 0.170 12.267 1.300 0.050 0.090 0.085 0.091 1.730 0.045
Al (T) (mg/l) 4.417 2.348 5.878 14.400 0.940 7.752 6.830 8.041 14.700 3.730
As (T) (mg/l) 0.005 0.001 0.008 6.830 0.001 0.005 0.002 0.007 0.015 0.001
Cu (T) (mg/l) 0.015 0.004 0.014 0.200 0.001 0.021 0.010 0.018 0.200 0.009
Fe (T) (mg/l) 93.96 78.78 109.76 216.00 13.80 31.65 27.40 31.65 55.60 13.20
Mn (T) (mg/l) 30.22 28.58 31.45 42.80 15.60 20.51 16.12 20.51 83.70 6.05
Ni (T) (mg/l) 0.068 0.062 0.070 42.800 15.600 0.063 0.06 0.06 0.12 0.03
Pb (T) (mg/l) 0.010 0.003 0.015 42.800 15.600 0.007 0.00 0.01 0.05 0.00
Zn (T) (mg/l) 0.146 0.119 0.174 0.295 0.064 0.091 0.08 0.09 0.14 0.05
(T) Total (D) Dissolved TB: A and B Dam discharge to Ring River Arm TC: C Dam discharge to Argent River Arm S1: C Dam seepage to Argent River Arm S2: C1, A and B Dam seepage to Lake Pieman
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 9
2.2 D Dam Design
This section describes D Dam’s key design elements, the layout of which shown on
Figure 2-1. D Dam is designed for downstream construction, in a series of lifts to an
ultimate height of 180 m AHD. D Dam is designed to store approximately 16 years of
tailings and involves the construction of an encapsulated waste rock cell in the upstream
side of the embankment to address current waste rock disposal needs.
2.2.1 Capacity
In total D Dam will be able to store approximately 6.5 million m3 of tailings. This
represents approximately 16 years of tailings storage capacity at current production rates
and will provide storage for the remainder of the foreseeable life of the mine, based on
measured, indicated and deferred deposits (BMT JV 2013).
2.2.2 Project Footprint
The TSF has a maximum footprint on closure of approximately 48.9 ha of which an
estimated 13.3 ha is already disturbed. The total area of borrows is 22.9 ha, of which an
estimated 5 ha is already cleared or disturbed. The approximate extent of these footprints
is shown on Figure 2-1.
2.2.3 Tailings Pipeline
Tailings will be supplied from the existing Renison processing plant to D Dam along two
discharge pipelines of 150 mm and 250 mm diameter (high and low sulphur tailings
respectively).
The pipeline traverses existing operational areas and uses existing site access roads as
shown on Figure 1-1 and is approximately 2 km to D Dam, where the HST and LST lines
will split and aligned depending on the stage of the deposition strategy.
Pipeline will be inspected daily for leakage and wear that may lead to failure. Spills will be
covered as with other environmental incidents by the Operational Environmental
Management Plan (see Section 6.3)
2.2.4 Embankment Stages
The TSF embankment retains tailings and water while the tailings settle and effluent,
minus the tailings, is decanted. The embankment is designed as water retaining,
containing a clay core with a permeability of 2 x 10-8 m/s.
The D Dam embankment will be constructed to an initial (Stage 1) level prior to operation.
As the mine develops, the dam capacity will be increased by a series of staged lifts to suit
storage requirements and operating capital expenditure as tailings fill the TSF to a final
design level of 180 m AHD (see Table 2-2).
Table 2-2 D Dam Levels
Stage Crest Level (m AHD) Cumulative Capacity (Mm3)
Stage 1 168 m 2.5
Ultimate level 180 m 6.5
Total 6.5
At Stage 1, the embankment (see Figure 2-3) will comprise three sections:
The main embankment (D1 & D2) forming the northern wall of the storage. The
tailings will be discharged along the full length of this embankment;
10 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
The ridgeline embankment (D3) between the main embankment and the decant
embankment; and
The decant embankment (D4) forming the southeast corner of the storage towards
which the decant pond will gradually move.
As the embankment develops, these sections will rise above the existing topography and
meet to form one continuous embankment. The PAF waste rock cell (see Section 2.4) will
be constructed on the upstream side of the main embankment (D2) during the Stage 1
construction.
2.2.5 Embankment Geometry
External
The geometry of the embankment is summarised in Table 2-3. A typical cross-section of
the embankment is provided in Figure 2-2.
Table 2-3 Embankment geometry
Description Design
Crest level Stage 1 168 m AHD
Ultimate 180 m AHD
Dam Height
Stage 1 38 m (maximum)
Ultimate 50 m (maximum)
Crest width 8 m
Upstream batter 1:2.0 (V:H) – D1, D2, D4 embankments 1:2.5 (V:H) – D3 embankment
Downstream batter 1:2.25 (V:H)
Clay core Central clay core with a base width equal to half the height.
Grout curtain Grouting will be restricted to those areas below the embankments where rock is at or near to the surface of the embankment foundations (see Section 2.2.6).
Internal
The internal structure of the embankment comprises the zones described in Table 2-4.
Typical embankment sections illustrating these zones are shown on Figure 2-2.
The sources of materials for the different embankment components are described in
Section 2.3.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 11
Table 2-4 Embankment internal zoning
Zone Description Material Purpose
1 Low permeability material used for the core zone of the embankment.
Clay / silty clays Provides the water retention in the embankment.
2A Primary Filter Medium to coarse grained sand
Filter layers to control water movement, hydrostatic pressures and erosion in the embankment.
2B Secondary Filter Gravel Drainage Medium.
Gravels
3A Random rock and earthfill Moderately to highly Weathered materials
Rockfill <200mm Provides structural strength of embankment.
3B Slightly Weathered to Fresh Rockfill.
Rockfill <500 mm
4 Select Coarse Rip-Rap/Rockfill. Rockfill <500 mm
Erosion protection.
PAF Cell
Cell containing PAF waste rock within a clay capsule (see Section 2.2.10).
PAF waste rock <500 mm Clay / silty clays
Disposal of PAF waste rock to control AMD.
C Dam Borrow
West Pieman Ridge Borrow
"C" Dam
"A" Dam"B" Dam
368,800
368,800
369,000
369,000
369,200
369,200
369,400
369,400
369,600
369,600
369,800
369,800
370,000
370,000
370,200
370,200
370,400
370,400
370,600
370,600
370,800
370,800
5,373
,400
5,373
,400
5,373
,600
5,373
,600
5,373
,800
5,373
,800
5,374
,000
5,374
,000
5,374
,200
5,374
,200
5,374
,400
5,374
,400
N:\AU\Hobart\Projects\32\16878\GIS\Maps\3216878_2-2_Ddam_Extents_RevE.mxd
© 2014. While GHD has taken care to ensure the accuracy of this product, GHD makes no representations or warranties about its accuracy, completeness or suitability for any particular purpose. GHD cannot accept liability of anykind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred as a result of the product being inaccurate, incomplete or unsuitable in any way and for any reason.
Figure 2-1
Job NumberRevision F
32-16878
Map Projection: Transverse MercatorHorizontal Datum: Geocentric Datum of Australia 1994
Grid: Map Grid of Australia, Zone 55
1:7,500
0 50 100 150 20025m
Date 03 Mar 2015
BMT JV Pty LtdRenision Bell, Tailing Storage Facility
DPEMP
D Dam Project Layout
Data source: Bluestone Mines Tasmania aerial photo 1997, GHD dam design 2012 and borrow areas 2014. Created by: JTO; updated by: jpulford & dtickner
2 Salamanca Square Hobart TAS 7000 Australia T 61 3 6210 0600 F 61 3 6210 0601 E [email protected] W www.ghd.com
LakePieman
EXTENT OF ULTIMATEENBANKMENT
EXTENT OF STAGE 1ENBANKMENT
DECANT TOWER
RingRiver
Discharge to Ring River
Culvert under Emu Bay Railway
TD Discharge Point Indicative Drainage Line for Decant
Decant Tower Decant_Pipeline
Existing dam
Final Dam Embankment Extent
Starter Dam Embankment Extent
Proposed Borrow AreaScale at A4 -
Widened ExistingAccess Road
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 13
Figure 2-2 Cross Sections
14 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
A) Starter Dam
B) Final Embankment
Figure 2-3 Embankment at Stage 1 and Final level
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 15
Figure 2-4 Seepage Control Features
Figure 2-5 Drainage Features
16 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
2.2.6 Seepage Control
Purpose
To maintain the stability of the embankment, it is necessary to control the rate of seepage
through its foundations.
Reducing the seepage has the added benefit of controlling potential movement of
dissolved contaminants (through Acid and Metalliferous Drainage) from within the TSF
into groundwater. However, the primary means of controlling AMD is preventing
acidification in the tailings through an effective Tailings Deposition Strategy (see Section
2.5.2).
Overview of Approach
As the foundations for D Dam vary significantly across the site a combined approach for
seepage control is required. This approach generally involves utilising the naturally low
permeability of tailings to reduce seepage rates and hydraulic gradient through the
embankment and couple this with grouting and limited clay liners of the decant pond and
key areas of high permeability on the dam floor.
The TSF floor will not be lined in its entirety. The rationale for this is explained in Section
2.11.3. Table 2-5 provides an indication of the relatively permeability of embankment
materials for reference.
Table 2-5 Permeability of Embankment Materials
Material Permeability k (m/s)
Zone 1 Clay 2 x 10-8
Zone 2 Filters 1 x 10-4
Zone 3A Random Earthfill 5 x 10-7
Zone 3B Rockfill (NAF/PAF) 1 x 10-5
Rip Rap 1 x 10-3
Tailings 1 x 10-7
Lacustrine Deposits 5 x 10-8
Fluvioglacial Deposits 5 x 10-8
Grout Curtain 1 x 10-10
From D Dam Stage 1 Preconstruction Report (Appendix O)
Grout Curtain
Grout (a mix of cement and water) will be injected into the foundations of sections of the
embankment (see Figure 2-4) where rock is at or near to the surface. In these areas
grouting fills permeable zones such as rock defects, joints and fractures to form a low-
permeability ‘curtain’ in the ground following the alignment of the embankment, thereby
reducing seepage.
Grout holes will generally be spaced at 6 m centres (based on previous experience in
similar foundation fracturing). The grout holes range from a depth of 15 to 40 metres
deep.
Further information on the grout curtain design is provided in Appendix O.
Storage Lining
During the first years of D Dam operations, tailings deposition will be targeted to develop
a blanket of tailings over the floor of the storage. As the tailings have a hydraulic
permeability approximately an order of magnitude less than the near surface rock, it will
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 17
act as a liner to limit seepage. Placing tailings against the embankments also reduces
seepage rates and hydraulic gradients through the embankments. Importantly the depth
of tailings increases as the embankment height increases thereby offsetting increased
hydraulic gradients with increased head losses due to seepage through the tailings.
However, in the first two years of operations, there will be areas of exposed foundation
that will be subject to operational and flood water levels. Fluvioglacial deposits may
contain gravely and cobbley zones which may act as foundation seepage conduits. All
exposed fluvioglacial materials will be inspected and mapped during the embankment
foundation and storage area stripping stage of the works. In particular, the contact
between the different geologies will be investigated for likely seepage paths. It is
proposed that permeable zones be capped on as required with a thick layer of reworked
clayey silts (lacustrine materials) in order to limit the risk of foundation seepage.
In addition to the above, the storage area in the vicinity of the decant pond will be lined
with reworked lacustrine materials as it will experience direct water contact for several
years before being lined with tailings.
PAF Waste Rock Cell
The PAF waste rock cell, as described in Section 2.4 will be encapsulated in a 1 m liner
of clay. This will form a further barrier to seepage in the main (D2) embankment
Pore Pressure Monitoring
Arrays of vibrating wire piezometers will be installed to monitor pore pressures within the
embankments:
D1 Embankment (CH100)
D2 (Main) Embankment (CH540 & CH660)
D4 (Decant) Embankment (CH1350)
Seepage Monitoring
V-Notch weirs will be installed in drainage channels downstream of the embankments S2,
S3 and S4 (see Figure 2-5) to capture and allow monitoring the seepage flow rate.
2.2.7 Decant
Decant Tower
Tailings water will decant via a gravity decant sloping up the upstream face of the decant
embankment (D4) in D Dam’s south-east corner as shown in Figure 2-5.
The decant tower comprises a 0.9 x 0.9 m square conduit of precast box culverts. At the
level reached by the tailings water a removable lid forms the intake and a grate will catch
debris.
The decant provides a stable structure allowing progressive raising of the decant pond
and to release water from rainfall events in a controlled manner.
Early Stage Decant Pumping
The base of the D4 embankment is at 162 m AHD. During the first 2 years of the TSF
operation the decant will collect in a point to the north of the tailings storage area which is
below this.
18 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
To allow this to decant via the decant tower a channel will be excavated which will allow
gravity draining once the decant pond reaches 155 m AHD (see Figure 2-5). ). In the 2
years before the decant pond reaches this level it will be pumped to the channel.
Decant Pipe
The pond level will be monitored using an automated gauged system with alarms at the
processing plant.
From the decant tower, the water will flow under the embankment and down the slope to
discharge point TD in a 630 mm HDPE pipe. Here it will discharge to the natural drainage
line running to the Ring River.
The discharge point will comprise a 600 mm diameter butterfly valve at the outlet which
will allow the discharge to cease if required.
The pipe will be installed within a trench excavated through natural ground under the
embankment. The decant pipe will be concrete encased through the entire decant
embankment. A diaphragm filter will be installed around the pipe to minimise the risk of
piping along the decant pipe.
Based on a 2.7 Mt production per year at 40% solids and average rainfall over the
catchment, the operating flows are estimated to be 0.13 m3/s for the D Dam catchment.
2.2.8 Decant Channel and Discharge Point
The discharge from the decant pipe at point TD will pass through a butterfly valve and be
discharged into a natural drainage line running to the Ring River marked on Figure 2-1.
Where the drainage line crosses under the Emu Bay railway line a new concrete culvert
will be installed using prefabricated units transported via the rail line. The environmental
disturbance for the installation of the culvert will be minimal if pipe jacking can be used
with nominal clearance of vegetation.
BMTJV will liaise with TasRail on the culvert installation specifications (to be approved by
TasRail to their standard) and access to undertake words within the rail corridor.
A number of alternative designs for the decant channel were considered during design
work. These are discussed in Section 2.11.
2.2.9 Storm Water Management
Stormwater Catchment
Due to the location of D Dam there is no significant catchment above the dam itself, as
this area is already occupied by A, B and C Dams, overflow from which is channelled to
the Ring and Argent Rivers along existing spillways
During early operations, where some of the TSF embankment is made up of natural
topography, a drained temporary access road within the footprint will be angled towards
the pond to minimise surface runoff from flowing into the dam catchment from outside. It
will also allow the retention of construction stormwater runoff from within the TSF to settle
in the decant pond prior to discharge to the environment through the decant tower.
On the closure of D Dam, overflow from A, B and C Dams will be channelled into D Dam
and the combined flow leave by a single spillway.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 19
Emergency Spillway
D Dam includes a rock-lined emergency spillway to allow the controlled runoff of overflow
during flood events. During the initial stages, the spillway will be excavated into natural
ground with an invert level 1 m below the crest. This will pass a 1:100,000 AEP flood
event while maintaining freeboard for wave run-up in a 1:10 AEP wind event.
The Stage 1 and final spill way positions are shown on Figure 2-5.
Once a complete embankment encircles the storage area, the spillway will take the form
of an overtopping embankment structure.
2.2.10 Existing Embankment Modifications
Where the D Dam embankment meets B and C Dams, the material on the downstream
faces of the existing embankments prevents direct connection of the D Dam clay core to
the impermeable cores of the existing embankments.
As the permeable material on these downstream faces could create a pathway for
seepage that would destabilise the D Dam embankment an additional barrier of clay
‘core’ material will be added to these downstream faces (see Figure 2-3).
Subsoil drains (shown on Figure 2-5) will be installed under these liners to prevent a
build-up of pore pressures within the existing embankments. The flow rates from the
subsoil drains will be monitored using v-notch weirs in order to continue the measurement
of known seepages from the existing dams.
Sumps and pumping system will also be included immediately downstream of the v-
notch weirs in order to pump the seepages into the D Dam decant pond to enable
ongoing treatment.
A temporary V-notch weir will be installed in the toe of the A dam embankment
Further detail on existing embankment modifications is provided in Appendix O.
2.3 Materials
2.3.1 Material Requirements
Material to construct the Project will be obtained from within the Renison lease as
identified in geotechnical investigations described in Appendix O. The sources of
materials for each of the embankment zones described in Section 2.2.5 are shown in
Table 2-6. The location of borrow areas is show on Figure 2-1.
20 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Table 2-6 Construction Material Volumes and Sources
Area Volume, +/- 20% accuracy (m3) Source Borrow*
Stage 1 Ultimate Totals Stage 1 Ultimate
Zone 1 178,100 165,400 343,500
D Dam Footprint C Dam Borrow
C Dam Borrow West Pieman Borrow
Zone 2A, 2B 30,600 93,700 124,400 D Dam Footprint
D Dam Footprint C Dam Borrow
Zone 2C 300 0 300 D Dam Footprint
D Dam Footprint C Dam Borrow
Zone 3A 181,300 661,300 842,600 D Dam Footprint
D Dam Footprint C Dam Borrow
Zone 3B 58,600 264,900 323,500 West D Dam Borrow
D Dam Footprint C Dam Borrow
Zone 4 26,000 3,300 29,400 West D Dam Borrow
D Dam Footprint C Dam Borrow
Embankment Subtotal
475,000 1,188,600
1,663,600
Mine Waste Rock
236,000 0 236,000 Stockpiles near Renison Mill
-
PAF Cell Lining
54,700 0 54,700 D Dam -
Storage Lining 19,000 0 19,000 D Dam -
Total Fill 784,700 1,188,600
1,973,300
Zone 1 Impermeable Materials
Zone 1 materials will form the clay core of the embankment. Suitable materials for this
purpose are found mainly within the low permeability, low plasticity sandy silts or clays in
residual and weathered rock.
Following the stripping of an assumed 2 m overburden, these deposits would be
excavated with an excavator.
Zone 2 Filter Sands
Sand sized filter material will be obtained by on-site crushing, screening and washing of
fresh rock (obtained in the same way as that for Zone 3 material below).
Zone 3 and 4 Crushed Rock
Zone 3 materials will be primarily sourced from excavation within the storage area to
maximise the storage capacity of the dam.
Generally, borrows will be developed by winning more weathered, Zone 3A materials
from above to expose the underlying less weathered Zone 3B materials.
Several borrows have already been developed within the storage area which have
removed the highly weathered material to expose the underlying Zone 3B material
enabling access to these materials at the beginning of construction.
Weathered 3A rock can be readily excavated by a 25 t excavator. As embankment
construction progresses, and for later raises, larger machinery (such as 45 t excavators),
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 21
ripping, drilling and blasting will be needed. These activities will take place within the
footprint of the existing and proposed borrows.
Final bench heights will be 5 m. All benches will be self-draining along the bench to a
suitable discharge point or settling pond. Benches will not overhang and batters will be
constructed at a safe angle.
A temporary crushing plant will be installed in the D Dam storage area to crush the
excavated rock to the required grade.
2.3.2 Borrow Development Plan
A preliminary borrow development plan has been prepared in order to maximise the use
of materials within the D Dam footprint and coordinate new borrow locations. The
sections below briefly summarise the proposed borrow development plan for the
construction of the starter dam and subsequent lifts.
Based on this plan and the geotechnical information available, there is sufficient material
available to construct D Dam.
Table 2-7 Borrow Areas
Borrow Pit Area (ha)
Vegetation Clearance (ha)
Estimated Depth (m)
Approximate
Volume (Mm3)
D Dam 20 0 (within D Dam Footprint)
10 2
C Dam Borrow
16.1 4.9 (disturbed) 11.2 (native)
15 2.4
West Pieman Ridge Borrow
6.7 6.7 (native) 10 0.7
Once fresh rock (including that to be crushed for sand) is exposed in a borrow area, it will
be tested for NAPP and NAG at a minimum frequency of 1 round of testing per 10,000 m3
of rockfill according to the “ARD Test Handbook, Project 387A” (AMIRA International Ltd,
2002).
Zone 3 materials placed onto the embankment will be Non-Acid Forming (NAF). Any
geochemically unsuitable rockfill will left in situ, or disposed of in the PAF cell.
Starter Dam Borrow Plan
The construction of the starter dam will maximise use of materials from within the D Dam
footprint to increase storage capacity and improve productivity:
First Zone 1 Clay will be taken from within the D Dam footprint, and Zone 3 rockfill
from slope-correction works in the West D Dam Borrow and the C Dam Borrow;
Once Zone 1 Clay fill has been depleted within the D Dam footprint, bulk Zone 3
Rockfill will be excavated within the D Dam footprint; and
Zone 1 Clay will then be taken from the C Dam Borrow.
22 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Subsequent Lift Borrow Plan
Materials for subsequent lifts will be extracted as follows:
Zone 3 Rockfill will continue to be extracted from the D dam tailings area until
tailings deposition operations restrict borrow development;
Zone 1 Clay will continue to be extracted from the C Dam Borrow. Once depleted,
extraction of the West Pieman Ridge Borrow will commence at the southern end;
and
Source Zone 3 Rockfill will continue to be taken from the C Dam Borrow. This plan
will require quarrying.
2.3.3 Environmental Management
Construction material borrow pits will be managed according to the requirements of the Mineral resources Tasmania Quarry Code of Practice, 1999.
Environmental management measures are described in the relevant sub-sections of
Section 4. Closure and rehabilitation of borrow areas is covered in Section 8.
Control measures for preventing PAF rock material from being excavated from the borrow
areas are described in Section 4.1.3.
2.4 PAF Waste Rock In D Dam
During D Dam TSF construction, it is proposed to use mine waste rock from existing
temporary surface stockpiles and dumps where the material is deemed geotechnically
and geochemically suitable. The waste rock will form a single upstream buttress zone on
the D2 (Main) Embankment to create a permanent storage solution.
In order to successfully store waste rock in the embankment of D Dam, management
measures are required to neutralise existing oxidation and manage future oxidation
potential.
In particular the waste rock will be encapsulated within an impermeable clay liner, will be
placed with a maximum elevation of 160 m AHD to allow it to be inundated and saturated
within two years and if required (based on testing) will be dosed with sufficient lime to
neutralise potential acidity until full inundation by tailings and water occurs.
2.4.1 Rationale
The Renison site has several surface deposits of waste rock requiring safe long term
storage. This rock is a mixture of:
Potentially Acid Forming (PAF) along with associated metalliferous and saline
drainage;
NAFM – metalliferous waste rock that is Non-Acid Forming (NAF) but with potential
to leach metals if oxidised; and
NAFNM - material that is NAF but non-metalliferous (NM) and hence has a low risk
of generating acidic, metalliferous or saline leachate.
This material, particularly that which is classified as Potentially Acid Forming (PAF),
requires additional geochemical management in order to minimise the risk of AMD. The
quantities and sources of these are listed in Table 2-8.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 23
Table 2-8 Waste Rock Sources
Storage Quantity (t)
Luck Pad 39,000
Live Storage 92,000
Bischoff ROM 81,000
HMS Scats 250,000 (estimated)
Underlying Tailings (Federal Slimes) 10,000 (estimated)
Total 472,000
Using waste rock within D Dam has a number of benefits:
It eliminates current storage of surface waste rock material as well as addressing
site surface legacy issues.
It minimises overall waste footprint upon mine closure by bringing the majority of
waste into a single area.
It minimises quantity of material required to be won from external borrow areas for
the D Dam embankment construction, thus reducing the borrow area footprints.
It provides additional geotechnical strength to the upstream embankment section
due to the waste being a higher strength material geotechnically than the standard
upstream zone materials used elsewhere in the embankment.
2.4.2 PAF Waste Rock Cell
As described in Section 2.2.4 D Dam will incorporate a cell in which to place the PAF
waste rock with capacity for 472,000 t waste rock.
The cell (shown in plan on Figure 2-1 and in section on Figure 2-2) will be approximately
325 m long by 100 m wide and at its deepest will be approximately 25 m deep.
The PAF Cell will be encapsulated within a 1 m thick liner of impermeable clay to limit
oxygen ingress. To support the clay, the outer 1 m of the PAF material will be a filter of
fine grained HMS scats. The cell will be clad with 1 m outer rip rap layer of NAF rock to
prevent erosion.
This capping will tie into the underlying clay liner at the toe of the embankment and into
the Zone 1 core at the crest.
All of the waste material will be placed below 160 m AHD which will allow it to be
inundated and saturated within two years.
2.4.3 AMD Classification and Lime Dosing
The geochemical properties of the waste rock has been well characterised though
extensive testing (See Appendix H).
BMTJV currently dose the stockpiles with lime twice yearly in order to achieve neutral
seepage.
During construction the rockfill will be neutralised through the addition of more hydrated
lime. The rate of application will be outlined in the AMD Waste Management Plan,
however it is expected that it will be at the current volume and concentrations as applied
to the waste rock storages as set out in the EPA letter to BMTJV titled ‘Temporary Waste
Rock Storage at Renison Mine’, dated 26 May 2014.
24 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
2.4.4 Handling and Placement
The following is an outline of the stages of PAF Cell construction:
Clear and grub footprint to suitable foundation;
Shaping and slope correction of foundation;
Place and compact clay liner from base of D2 embankment Zone 1;
Place and compact minimum 1.0 m thick SCATS over clay liner;
Install lower instrumentation (piezometer and oxygen sensor);
Place and compact waste materials. Placement of waste will take place in
conjunction with the embankment fill materials. 1.0 m wide SCATS layer will be
placed between the embankment core and any coarse rockfill. In no circumstance
will zones of coarse rock be allowed adjacent to the Zone 1 core or clay liner;
Install upper oxygen sensor;
Place and compact 1.0 m thick SCATS layer of the coarse rockfill;
Place and compact 1.0 m thick clay cap. This will tie into the Zone 1 core at the top
and the clay liner underneath; and
Place and compact 1.0 m thick Select Zone 3A material over clay cap. Erosion of
this capping layer will be monitored though routine engineering checks and
repaired as required until the cell is covered with tailings.
2.4.5 Preventing Oxygen Ingress
Once placed, the waste material will be capped to limit further oxidation of the materials
completing the encapsulation.
Acid Sulphate Generation Rates (ASGR) reduces with saturation and thickness of tailings
cover. The required degree of saturation to prevent oxygen ingress at different depths of
cover shown in Table 2-9. This is discussed in more detail in Appendix O.
Table 2-9 Required Saturation of Cover to Achieve 98% Reduction in ASGR
Cover Thickness (m) Required Degree of Saturation (Average over thickness of cover)
0 95%
1 (Clay Encapsulation) 80%
2 70%
5 60%
10 50%
12 (D Dam Closure) 45%
For the D Dam PAF cell the necessary levels saturation will be achieved as follows:
The initial 1.0 m thick cap will have Zone 3A material which will hold water and
provide water to the underlying material to maintain saturation levels. It will also
minimise drying and cracking by reducing potential evaporation.
During operation the PAF cell will have a saturated cover from LST above, that will
increase in thickness over time.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 25
On closure, there will be 12 m of tailings cover over the PAF Waste Storage Cell
which will maintain saturation levels in excess of the required 45%.
2.4.6 Testing, sampling, tracking of materials
All PAF material will be classified and tracked between source and deposition in the PAF
cell. Geochemical testing will take place as described in Section 2.4.3.
2.4.7 Monitoring
The PAF cell will include oxygen sensors at the top and base of the PAF material and a
piezometer to monitor water level in cell.
2.5 Operation
2.5.1 Tailings Composition
Tailings Streams
The Renison Processing Plant produces a high sulphur tailings (HST) and low sulphur
tailings (LST) streams made up from different tail streams within the Process plant (see
Table 2-10).
Table 2-10 Composition of the HST and LST Streams
Stream Component Percentage Total (w/w)
% S [total S]
High Sulphide Tailings (HST)
Final Sulphide Concentrate (FSC)
26.0% 20 13.5
Slime Tail (SLT) 15.9% 3
Low Sulphide Tailings (LST)
Cassiterite Flotation Tail (CFT) Slime Tail (SLT) Ultra Fine Tailings (UFT)
58.1% 0.4
From Renison Operation EMP (BMT JV, 2013)
Tailings characteristics vary with time depending on the ore being processed by the plant.
Analysis of recent tailings samples (see Appendix H) and the reported mineralogical
prognosis for current ore deposits indicates that the proportions in Table 2-10 are worst
cases with the trend being towards of higher proportions of LST.
Notwithstanding a future reprocessing project (Section 2.11.1), BMT JV only anticipates
processing ore from Renison mine during the life of this TSF. Any processing of ores from
other sources would be subject to further assessment and approval from the EPA.
The tailings will be neutralised with hydrated lime slurry at the processing plant to a
nominal pH 8.5. This neutralises any free acid and precipitates metals, sulphate and
fluoride.
Tailings Acid Generating Potential
A series of recent tailings samples were tested for their acid generating potential.
Figure 2-6 shows the Net Acid Generation (NAG) and Net Acid Producing Potential
(NAPP) for the HST and LST streams. It indicates that the LST ranges from non-acid
forming to acid-consuming, whereas the HST are all high-capacity potentially acid-
forming. Full details are contained in Appendix H.
26 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Figure 2-6 Tailings Geochemical Classification
Potential Metal Toxicants
The samples were analysed for their metal content, with full results presented in
Appendix H. The testing found that the HST sample contained elevated levels (based on
a Geochemical Availability Index or GAI or 3 or more) of 13 metals that might represent a
risk of metalliferous leachate or drainage with arsenic is likely to be the most significant.
In contrast, the LST sample has low NAG and only for six potentially leachable metals,
although again arsenic is likely to be the most significant. This indicates that the HST has
highly elevated metal levels that may generate metalliferous drainage, but that the LST is
a much lower risk.
2.5.2 Tailings Deposition
Aims
The D Dam tailings deposition strategy has the following aims:
To uphold environmental water quality and discharge standards.
To minimise generation of AMD during operations and closure.
To ensure their stable long term storage.
To enhance dam safety by developing a LST beach against the embankments.
11.5
22.5
33.5
44.5
55.5
66.5
77.5
88.5
99.510
10.511
11.512
-200
-150
-100 -5
0 050
10
01
50
20
02
50
30
03
50
40
04
50
50
05
50
60
06
50
70
07
50
80
08
50
90
09
50
100
010
50
110
0
Ne
t A
cid
Ge
ne
rati
on
"N
AG
" p
H
Net Acid Producing Potential "NAPP" (kgH2SO4/t)
Sample 1 LST Sample 2 HST Sample 3 LST
Sample 4 HST Sample 5 LST Sample 6 HST
UC
NAF
NAF = Non‐acid‐forming , PAF = Potentially Acid Forming, LC =Low Capacity, HC = High Capacity, UC = Uncertain, ACM = Acid Consuming
PAF HC
ACM
UC
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 27
To maximise the tailings capacity of the dam.
Principle
The deposition strategy separates LST and HST streams to minimise the area in which
HST are stored. As it fills this will allow the TSF to contain the HST in a flooded area
whilst creating an LST beach against the embankment, thus improving stability and
allowing water cover for the HST in case of planned or temporary closure.
Stages
The deposition of the tailings changes as the TSF fills. The following section described
the evolution of the tailings at four stages:
End of Year 1 (Tailings at 155 m AHD);
End of Year 2 (Tailings at 160 m AHD);
D Dam full at 180 m AHD; and
D Dam Closure.
End of Year 1 (Tailings at 155 m AHD)
In the first year of operations the deposition will be ‘all-in’ into the lowest areas within the
storage, upstream of the PAF Waste Storage Cell. The deposition will be mainly sub-
aqueous with deposition as follows:
LST deposited via spigots from the top of the PAF cell.
HST will be deposited from the lowest point within the middle of the storage area.
During the first two years of operations, the level of the decant pond will be managed by a
movable decant pump. The pump will transfer water from the pond to the higher level
decant channel which will then flow via gravity to the decant tower.
End of Year 2 (Tailings at 160 m AHD)
In the second year, the tailings will begin to rise above the decant pond forming a beach.
The LST deposition will initially target the eastern side of the storage to develop a
tailings ‘blanket’ over the natural surface within the storage area. Once the ‘blanket’
is achieved through this area, deposition will switch to the western side of the
storage to form a beach against the D1 embankment.
The HST will continue to be deposited from within the middle of the storage area at
the lowest available point. The HST will be deposited sub-aerially with the
maximum level for HST deposition at or below the maximum level of the LST
beaches adjacent to the PAF Waste Storage Cell.
Sub-aerially deposited HST will be covered by fresh HST within 6 to 8 weeks to
prevent oxidation.
During this period the level of decant pump station will rise to allow the pond level to
increase and maintain quality of pumped water. It is expected by the end of Year 2, the
pond level have reached that of the decant channel from where it can drain by gravity
without the pump, which would be removed.
28 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Year 3 to filling of D Dam to 180 m AHD
The LST will be evenly deposited via spigots along the length of the embankments
to maximise the density and strength of the tailings around the perimeter of the
storage.
HST will be deposited sub-aerially from the south. The maximum level of the HST
will be maintained 1.5 m below the LST in order to allow flooding without relying on
the embankment as a water retaining structure, providing a lower risk dam in the
event of early closure.
Moving towards closure, the HST deposition will progress east towards the decant
pond, with LST overlying the material in the south with final deposition HST
deposition being sub-aqueous.
D Dam Closure
As outlined in this report, the intent is to close the facility with a combined vegetated LST
beach and water cover over the HST. The tailings deposition has been designed to
develop a LST beach that does not require a cover to prevent the generation of AMD.
The HST will be deposited from the south of the facility with a lower level that will be
flooded on closure.
Figure 2-7 Illustrative Cross Section on Closure
Tailings Management Plan
Prior to commissioning of the D Dam, a detailed Tailings Management Plan (TMP) will be
developed by BMTJV to document all elements associated with the deposition and
storage of tailings within the dam.
2.6 Water Balance
Appendix F contains a water balance assessment for D Dam. The estimated volumes of
water in and out of D Dam for wet month, dry month and total annual conditions are
shown on Figure 2-8. Management of the seeps and discharges is addressed in Section
2.7.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 29
Figure 2-8 D-Dam Water Balance
All volumes are total flows over the specified period
Minimum Monthly Outflow Scenario
February 2007 Evaporation: 22 ML Rainfall: 7 ML Tailings: 139 ML
D Dam Seepage: Water retained:
A,B,C Dam Seepage:
Seepage to groundwater:
Decant:
Average Total Annual Outflow
Evaporation: 216 ML Rainfall: 977 ML Tailings: 1,808 ML
D Dam Seepage: Water retained:
A,B,C Dam Seepage:
Seepage to groundwater:
Decant:
Maximum Monthly Outflow Scenario Evaporation: 12 ML Rainfall: 263 ML Tailings: 153 ML
August 2013
D Dam Seepage: Water retained:
A,B,C Dam Seepage:
Seepage to groundwater:
Decant:
5 ML
394 ML
115 ML
4 ML
10 ML
4 ML
13 ML
56 ML
152 ML54 ML
2,450 ML 126 ML
11 ML
5 ML 13 ML
30 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
2.7 Wastewater Flows
The following sections describe the waste water flows into and out of the TSF. Discharge
and seepage points are shown in Figure 3-3, page 53.
2.7.1 Tailings Effluent
Lime Treatment of Process Plant Water
Untreated processing plant water has elevated levels of iron, manganese, arsenic, heavy metals, sulphate and fluoride.
The tailings effluent discharged from the processing plant will be treated with hydrated lime (calcium hydroxide) to an approximate pH of 8.5 before being deposited into the TSFs (as is currently the case).
Lime dosing will also respond to the pH levels monitored within the decant pond to retain the pH discharge limits. This will provide any additional neutralising of seepage entering the decant pond from A, B and C Dam.
The addition of hydrated lime has the following effects:
Neutralise any free acid in the tailing streams;
Precipitate iron (and co-precipitated and absorbed heavy metals such as arsenic which may be soluble, in isolation at this pH);
Precipitate most manganese;
Precipitate heavy metals;
Precipitate sulphate as gypsum; and
Precipitate fluoride as fluorite.
The water chemistry will then be relatively low in metals with sulphate and fluoride levels
controlled by gypsum and fluorite solubility.
Tailings chemistry from three tailings streams are tested every twelve hour shift for XRF
analysis. In addition, column leaching is carried out (kinetic testing) and periodically
samples are submitted to an external laboratory for standard Acid-Base Accounting
(ABA) tests.
Decant Water Quality
Table 2-11 presents the anticipated D Dam decant chemistry based on a geochemical
assessment of recent tailings and compares them with EPN 7092/2 limits. Appendix G
contains full details including assumptions on which the estimate is based.
Flow rate will be measured fortnightly at a v notch weir and fortnightly samples will be
taken for the analysis of a range of parameters as discussed in Section 5.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 31
Table 2-11 Predicted TSF Discharges
Parameter *Predicted D Dam Discharge (TD)
Predicted TD mass load kg/d
EPN 7092/2 limit for current TC discharge
pH 6.57 N/A >5.9
Total Cd (mg/l) 0.00011 0.00062 0.005
Total Co (mg/l) 0.0050 0.028 0.12
Total Cr (mg/l) 0.00014 0.00079 0.015
Total Ni (mg/l) 0.012 0.067 0.14
Total Cu (mg/l) 0.005 0.028 0.1
Total As(mg/l) 0.041 0.23 0.15
Total Fe (mg/l)** 6.04 50
Dissolved Fe (mg/l) 0.0754 0.423
Total Pb (mg/l) 0.00028 0.0016 0.06
Total Zn (mg/l) 0.0252 0.142 0.5
SO4 (mg/l) 1826.13 10,255.55 2200
Total Cl (mg/l) 40.78 229.02
Total Al (mg/l) 0.147 0.83
Total Ca (mg/l) 572.11 3212.97
Total K (mg/l) 34.28 192.52
Total F 13.80 77.5
Total Mg (mg/l) 75.63 424.74
*Estimated from existing tailings geochemistry from 2013 /14(see Appendix H).
2.7.2 D Dam Seepage
Three 2D finite element seepage models were performed for the new TSF using the
Rocscience Slide 6.0 software package (Groundwater mode) as described in Appendix
O.
These take into account the seepage control measures described in Section 2.2.6. With
these measures the estimated combined seepage from the embankment and tailings floor
is 5.7 l/s (180 ML/year).
Seepage will collect in the embankment toe drains and flow to the following discharge
points (as shown on Figure 2-5):
S2: Where the main embankment (D2) discharges to a natural drainage line;
S3: where the decant embankment (D4) mixes with the decant and discharges to
a natural drainage line; and
S4: Where the D1 Embankment discharges to a natural drainage line.
As discussed in Appendix H the quality of the seeps from D Dam is expected to be
approximately the same as that estimated for the decant in Table 2-11.
2.7.3 Seepage from Former TSFs
Historical seepage is described in Section 2.1.4, and involves two main seepage routes;
S1 which is seepage from the western side of C dam and S2 which is a combined
seepage flow from dams A, B and C. These are displayed on Figure 2-5.
Once D Dam is in place, the A, B and C Dam seeps that make up Seepage S2 will be captured by D Dam:
32 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Part of the seeps from C Dam (C1 – the component currently reporting to S2) and
B Dam will be caught by subsoil drains below the new clay ‘cores’ described in
Section 2.2.10. On emerging from the D Dam embankment seepage will flow
through a v-notch weir and collect at seepage intercept sumps for pumping to the D
Dam decant pond and treated with a sufficient quantity of lime.
Seeps from A Dam will flow into the D Dam storage area initially at a similar rate to
the present, decreasing with time as the tailings levels in D Dam increase, reducing
the hydrostatic head behind the A Dam embankment and gradually halting the
seepage in A Dam.
Seepage S1 from C Dam will remain largely unchanged and will still discharge to the
Argent River Arm of Lake Pieman.
2.7.4 Surface Water Flows from Former TSFs
Once operational, D Dam will become the sole TSF for Renison and all other TSFs will be
closed. After this, the residual discharges from the other TSFs will comprise seepage
(see Section 2.2.10) and runoff due to rainfall, comprising average annual flows of
approximately:
20 l/s to the Argent River via the existing discharge from C Dam.
9 l/s to the Ring River from A and B Dam via the existing discharge (remaining A
and B dam runoff will flow to D Dam via an overflow).
Further detail on discharge estimates can be found in Appendix F (water balance).
Further rationalisation of drainage will occur after closure, as described in Section 8.
2.8 Plant Requirements
D Dam will not require any fixed plant, but will require mobile pumps for:
Pumping decant for the first 2 years of operation (see Section 2.5.2).
Pumping seepage from interceptor sumps to the decant pond (see Section 2.2.10).
2.9 Site Services and Offsite Infrastructure
No offsite infrastructure is required for D Dam construction activities.
Other than that described above, D Dam will require no new site services (such as,
potable water supply, telecoms, or domestic waste water lines). Temporary portable site
amenities and mobile offices will be used during construction.
2.10 Construction
2.10.1 Development Sequence
D Dam construction is to be completed in a series of steps, with each incrementally
increasing the storage capacity as required. Timing of the construction will be dependent
on the development of the mine and the need for tailings capacity.
Based on the current planning for Renison underground mine only, a construction start in
2015 and an assumed tailings density of 1.8 t/m3, the following indicative staging is
anticipated:
Site preparation – 2015
Construction to Stage 1 Crest (168 m AHD) – 2015/2016
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 33
Raise to Ultimate dam crest (180 m AHD) – 2028
2.10.2 Stage 1 Construction
The proposed construction activities are shown in Table 2-12.
Table 2-12 Stage 1 Indicative Construction Programme
Construction Phase
Description Timing
Mobilisation and site preparation
Equipment mobilisation; upgrade existing access road; clearing and grubbing of D Dam footprint; excavation of unsuitable foundation materials.
First year construction
Diversion drainage works
Placement of a perimeter stormwater diversion drainage system, starter dam for water diversion and construction of temporary sediment control structures.
First year construction
Grouting program
Foundation preparation, drilling and grouting curtain construction.
First year construction
Embankment placing
Placement of clay, filter and rockfill material and associated excavation; construction of rock-lined emergency spillway.
Second year construction
Outlet works Installation of decant pipe and associated trench excavation; placement of decant embankment; installation of phase 1 sloping decant tower using a system of precast box culverts.
Second year construction
The estimated construction period for D Dam Stage 1 is approximately two years.
The timing of clearance will depend on a range of factors, namely:
Tailings storage requirements.
The timing of approval.
Weather conditions, the best period for construction being during the drier months
of December to April. Outside this period bad weather can make access and
placing clay difficult.
The breeding seasons of threatened species. Section 4.3.3 explains the best
clearance timings to minimise impacts on threatened species.
The timing of clearance will aim to balance these criteria. Nonetheless the mitigation
measures described in Section 4.3.3 will apply where clearance needs to take place
during a breeding season.
Rock may be excavated at borrow areas and in the footprint of the embankment.
Although it is unlikely that these will be Potentially Acid Forming, if geological assessment
deems it necessary then geochemical testing will be undertaken to confirm geochemical
characterisation. Any exposed rocks from borrow excavations with a high risk exposure
would be capped with clays.
The useable timber will be extracted and the remaining vegetation will be cleared using
bulldozers to the edge of site. No controlled burning of cleared vegetation is proposed.
The generation and management of construction wastes are covered in Section 4.6.
34 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
2.10.3 Construction to 180 m AHD
Approximately five years after D Dam tailings deposition commences, a series of raises of
will take the embankment to its final level of 180 m AHD, using a downstream
construction.
The construction of these stages will be concurrent with tailings discharge and water
management and each will be subject to the relevant approvals.
2.10.4 Construction Plant
Construction equipment will involve standard earthworks equipment including, but not
limited to, articulated dump trucks, excavators, drill rigs, dozers, rollers, grader, water cart
and light vehicles.
Processing on site construction material will require a mobile crushing and screening
plant.
Filter sand will need a sand washing plant.
2.10.5 Construction Traffic
Since the majority of construction material is being sourced from within the Renison
lease, the only significant heavy vehicle traffic created on local roads will be during
mobilisation and demobilisation when the approximate number of 2-way trips would be
25 (comprising 10 articulated dump trucks, 6 excavators, 3 dozers, 3 rollers, 2 drill rigs,
water cart, fuel cart). Construction personnel will generate approximately 15 2-way light
vehicle movements each day the during of the project. These movements compare with
901 daily 2-way movements (AADT) on the Zeehan to Melba Flats section of the
Murchison Highway (DIER, 2012).
The main construction traffic will comprise internal movements of trucks moving
construction material from the borrow areas to the embankment site. These will operate
during day time and at a maximum speed of 40 km/h.
2.10.6 Construction Working Hours
Proposed construction working hours are 12 hours a day, 7 days a week.
2.10.7 Borrow Area Haul Road
The site will be accessed by existing roads within the Renison lease. Temporary access
tracks will be constructed within the D Dam footprint.
A formal haul road following the toe of C Dam will connect the D Dam footprint and the
West Pieman Ridge, and C Dam Borrow Areas. This is shown on Figure 2-1 and will be
formed by widening an existing access track for approximately 700 m.
This may require minor earthworks and widening from approximately 6 m at present to 10
m. It would result in approximately 0.28 ha additional land take through already land
disturbed by previous construction activities.
2.10.8 Topsoil and Cleared Vegetation
Mature timber will be felled and removed selectively for use as timber by a designated
logging contractor.
The remaining vegetation will be cleared outwards from the centre of the D Dam footprint
and, progressively, from each of the borrow areas and piled in berms at the edge of each
site.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 35
These berms will also act as barriers to sediment runoff, avoiding the need for sediment
fences around the embankment footprint.
Topsoil is likely to be thin or non-existent, but any topsoil of significant depth will be
transferred to C Dam as part of closure and rehabilitation.
2.10.9 Commissioning
Major commissioning activities for D Dam are listed below in order of completion:
Monitoring of water stored in D Dam after construction of the embankment and
prior to commissioning, including that from seepage from the upstream TSFs. The
decant tower can be used to control the decant pond level, preventing discharge
until water quality meets statutory limits.
On first discharge of tailings, start-up checks on tailings pipeline and tailings
discharge point/points to be completed for inspection of leaks. (Additional to
pressure testing of pipe on completion of installation of discharge pipe).
Comprehensive dam surveillance inspection on first filling of TSF as per ANCOLD
“Guidelines on Dam Safety Management” 2003. This includes review of
instrumentation and monitoring data relevant to dam safety.
Commission decant tower on confirmation of decant pond meets discharge quality
requirements.
Management of any water, including rainwater and seepage, collected behind the
embankment prior to tailings deposition (see Section 4.1.2).
Review of tailings discharge management three months after commencement of
discharge.
2.11 Technical and Management Alternatives
A number of technical and management alternatives have been considered during the
development of the D Dam designs. These options fall into the following categories:
Rentails
Siting Options
Dam Design
Tailings Deposition Methods
Tailings Management Techniques
Decant Discharge Options
Closure Options
2.11.1 Rentails Project
The Rentails Project would involve removal of the existing tailings from A, B and C Dams
by dredging then reprocessing the tailings in a purpose built new plant for extraction of
residual tin. The tailings in C Dam would be dredged first with the reprocessed tailings
being stored in D Dam. Eventually C Dam will be emptied and D Dam will be nearing
capacity.
No decision has been made to commence Rentails which is still at a feasibility study
phase. The D Dam proposal does not depend on Rentails, as D Dam caters for tailings
generated from normal underground operations at Renison.
36 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
The C Dam embankment modifications must be done as part of the D Dam construction
regardless as to whether a decision on Rentails has been made, as the modifications
become impossible post commissioning of D Dam and filling with tailings from normal
Renison operations has commenced.
The closure concept outlined in Section 8 can be delivered if Rentails was to proceed.
However further design work would be required and any new potential environmental
impacts assessed separately.
2.11.2 TSF Siting Alternatives
In preliminary studies completed by Thompson & Brett in 2004, a number of alternative
dam sites were considered, all of which were outside of the current mine lease:
Exe Creek
Ring River
Dunkley
Crimson Creek
All of these alternative sites are outside of the current mining lease and a considerable
distance from the existing mine and other TSFs. The preferred D Dam site however is
within the existing lease and immediately adjacent to the existing TSFs and therefore
existing disturbance.
Exe Creek
Environmentally, although no threatened communities are shown in TASVEG, the site is
heavily vegetated and significant clearing would be required. The site is likely to be visible
from the Murchison Highway.
The Exe Creek site lies on Crown Land to the south-east of, and at a similar elevation to,
the mine site. The Exe Creek site is capable of storing in excess of the maximum
predicted tailings storage requirements. Security and management of uncontrolled
releases of tailings from the pipeline would be an issue at this site, in comparison to the
preferred site, due to its isolated nature and distance from existing mining operations.
Ring River
Environmentally, the site encompasses a large catchment area compared to all other
sites and a major spillway would need to be constructed. The dam design would need to
provide a substantial diversion pipe and spillway to cater for river flow during construction
causing additional landtake and potential hydrological impacts. Management of
uncontrolled releases of tailings from the pipeline would be more difficult at this site
compared to the preferred site. In addition, the impact of contaminated water from
upstream would need to be assessed.
The Ring River dam site is on Crown land outside the current mine lease, and is capable
of storing well in excess of the maximum predicted tailings storage requirements.
However, as well as the environmental complications, this option has a large cost in
terms of diversion pipes and spillways.
Dunkley
Environmentally the Dunkley site would not require major clearing and is not visible from
public viewpoints. Management of uncontrolled releases of tailings from the pipeline
would be complicated by distance from the mine site.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 37
Although this site is capable of storing well in excess of the maximum predicted tailings
storage requirements, the elevation and distance from the mine site would result in high
pumping costs.
Crimson Creek
Similar to Dunkley Creek, this site is capable of storing well in excess of the maximum
predicted tailings storage requirements, however the elevation and distance from the
mine site would result in high pumping costs.
D Dam (Preferred Location)
D Dam was chosen as the most viable option for a number of reasons. A preliminary
environmental assessment did not identify any major environmental constraints with any
of the sites assessed. D Dam is preferred as it is immediately downstream of current
storages, minimising the mining footprint and impact of the current tailings seepage on
downstream watercourses. Also, all other potential sites are a considerable distance from
the existing site and the further the storage is from the plant site, the longer the discharge
pipeline and the harder it is to manage and secure uncontrolled releases of tailings.
The D Dam option also has the following advantages:
Potential to reduce costs with utilisation of existing infrastructure
Easy staged development
Reuse of materials from existing storages (if Rentails proceeds)
Within existing lease area
Offers a method to capture a large portion of historical acidic seepages from the
existing TSFs
Existing geotechnical information can be utilised
2.11.3 TSF liner
Lining a TSF with an impermeable layer such as a clay barrier is one method that is
sometimes employed to reduce flows from the TSF to groundwater. While the proposed
design included limited storage lining for dam safety, the alternative for full storage lining
was not adopted for D Dam for the following reasons:
The grout curtain and other measures described in Section 2.2.6 provide sufficient
control of seepage to maintain dam stability.
Some seepage will occur even with a liner and the only true way to prevent
polluting waters seeping to groundwater is to prevent the formation of AMD in the
first place which is role of TSF tailings deposition strategy (see Section 2.5.2) and
regular monitoring (see Section 4.1.5).
Obtaining the additional clay needed to create the barrier would require additional
borrow areas with associated ecological impacts and potential impacts of transport.
2.11.4 Tailings Deposition Methods
The following alternative beaching and discharge methods were considered:
Sub-aqueous tailings deposition of HST component;
Twin Line discharge versus single line discharge.
38 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Sub-aqueous deposition was expected to cause low tailing density resulting in a taller
embankment, increasing material volumes and cost.
Single line discharge prevents the separate discharge of HST and LST to manage AMD.
The current plan for tailings discharge is to spigot LST tailings from the D Dam
embankments and use end point discharge for the HST from the southern side of the
dam.
2.11.5 Tailings Management Techniques
The two main recognised techniques for preventing AMD are:
Cover HST tailings with water. Where re-suspension of fine tailings due to wave
action is a consideration, a cover of one to three metres is needed (INAP, 2012).
One metre has been cited as an accepted industrial standard in some North
American publications (Yanful et al, 2004) whilst two metre cover depths have
been used in Australian mining examples (Benambra Mine Site case Study, INAP,
2012). A one metre cover is considered an appropriate depth given relatively short
fetch and the long term / permanent placement of the cover post closure.
Cover HST tailings with an inert material that is largely saturated; 90 % saturation
is considered equivalent to a water cover. Below 90 % saturation some oxidation
occurs and the amount of oxidation increases as the percent water saturation
decreases.
Using a water cover over all the tailings to manage oxidation of tailings has the following
limitations:
Sub-aqueous deposition of tailings can result in up to 25 % less storage capacity
than sub-aerial deposition.
The optimum water cover is often quoted as 2 m. This combined with the free-
board reduces TSF storage capacity considerably.
In order to maximise storage capacity, minimise geotechnical risk and have the better
closure position, sub-aerial deposition of tailings has been adopted where HST and LST
deposition is zoned within the TSF (see Section 2.5.2).
2.11.6 Decant Channel Options
The following options for the decant channel were considered as part of the design:
Ring River via natural drainage channel
Ring River via pipeline with diffuser
Lake Pieman via pipeline
An option to discharge to the Ring River via a HDPE lined channel was considered not
feasible due to the very steep nature of natural drainage line. These options and the
engineering and environmental issues associated with the options are summarised in
Table 2-13.
The preferred option is the discharge of decant water to the Ring River via the natural
drainage channel. This was due to the low vegetation clearance required in comparison
to the two engineered options. The potential impacts of the tailings decant on the channel
are discussed in Section 4.1.4.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 39
Table 2-13 TD Discharge Options Assessment Summary
Ring via natural drainage channel
Ring via pipeline Pieman via pipeline
Construction Feasibility
Easy. Simply requiring New 600 mm culvert under railway.
Moderate difficulty. 280 m of 600 mm pipe with concrete anchor blocks, an access road and silt traps. Access is difficult for pipe welders constructing and fixing concrete anchor blocks, supports under railway crossing.
Moderate-Difficult. Approx. 1.5 km of 600 mm pipe with pipe trenching. Concrete anchor blocks, access roads and silt traps. Access is difficult for pipe welders constructing and fixing concrete anchor blocks.
Operational requirements
Operational dam surveillance inspection of both decant channels will take approx. 1 hr per week.
Operational dam surveillance inspection pipeline will take approx. 3 hrs per week.
Operational dam surveillance inspection pipeline will take approx. 6 hrs per week.
Closure n/a Decommissioning of decant pipe.
Decommissioning of decant pipe.
Receiving Water Quality
Potential loss of water quality in ephemeral drainage line during operation
None None
Flora / Fauna Minimal clearance required.
Strip of c. 2,700 m2 of vegetation clearance.
Strip of c. 3,100 m2 of vegetation clearance.
Soil Potential contamination of soils within channel.
Potential soil erosion of cleared access and excavations
Potential soil erosion of cleared access and excavations
Other Sedimentation associated with road construction.
Sedimentation associated with road construction. Alignment outside of mine lease.
2.11.7 Closure Options
A number of closure options are available based on the current designs. The closure
options considered are:
Cap the exposed tailings beach developed during operations with a dry cap;
Use a combined soil/water (mushy) cover, similar to the system used on A and B
Dams that was proven to be effective (noting an LST cover only was placed);
Provide a minimum of 1 m water cover over the tailings surfaces to maintain
sufficient cover and prevent tailings oxidisation.
Of these the second is most desirable but relies on sufficient LST being generated prior to
closure. The preferred closure method and its benefits is described in Section 8.
40 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
3. The Existing Environment 3.1 Planning Aspects
3.1.1 Land Tenure and Title Details
Mining Lease
The mining lease associated with the Renison Bell Tin Mine (12 M/1995) covers an area
of 4662 hectares. It includes all of the mine and associated infrastructure described
above, as well as an extensive area of State Forest to the west and south.
Title
The footprint sits in Crown land parcel PID 6032097. The footprint abuts a private title
covering 40.47 ha with Certificate of Title Volume 210589 Folio 1 owned by BMT JV.
There are no encumbrances recorded on the title.
Although the site includes Crown land, Crown permission to lodge the development
application pursuant to Section 52(1B) of the LUPAA is not required as Section 52(1H)
exempts operations in a mining lease authorised under the Mineral Resources
Development Act 1995.
Reserves
A large part of the Renison Bell mining lease (including the project footprint) is subject to
a Regional Reserve under the Nature Conservation Act 2002. There is currently no
Reserve Management Plan.
Much of the western half of the Renison mining lease is designated as informal state
reserve on State Forest. The far southwest corner of the mining lease includes a small
area of the Parting Creek Regional Reserve.
Neither of these areas will be affected by the proposal.
3.1.2 Planning Controls
Planning Scheme
The site is subject to the provisions of the West Coast Interim Planning Scheme 2013.
The scheme sets the following objectives and performance criteria for developments in
this location:
Environmental Management Zone;
Part E.3 (Clearing and Conversion of Vegetation Code);
E.4 Change in Ground level Code;
E.10 Water and Waterways Code.
Clause 4.1.2 of the Scheme requires an application for a permit to include a copy of the
certificate of title, title plan and schedule of easements for the land on which the use and
development is proposed.
According to the List database there is no schedule of easements and no encumbrances
are recorded on the title.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 41
A full assessment of D Dam against these criteria is presented in Appendix B. The project
has been assessed as being in overall compliance with the applicable Scheme
provisions, including the relevant objectives and applicable development standards. The
TSF is discretionary pursuant to under Section 57 of LUPAA.
Mining Lease
The project relates to an existing Mining Lease (12M/1995) and fits within the definition of
mining operations under the Mineral Resources Development Act 1995, which states:
"mining operations" means any operations or work carried out on a lease area –
(a) To obtain or treat minerals; or
(b) To store or contain minerals or waste material generated by mining on that lease
area; or
(c) associated with mining;
The TSF is associated with mining and will store and contain minerals or waste material
generated by mining within the lease area.
3.1.3 Land Use History
Mining at the Renison Bell Tin Mine dates back to around 1890. The existing A, B and C
Dams have been constructed at Renison since 1968. Water is discharged from these via
seepage and overflow, including four licensed discharge points where water quality data
has been gathered since 1975. Observations during site surveys indicates that the D
Dam footprint has been selectively logged in the past and there is evidence of access
tracks, old borrow pits and geotechnical investigation holes associated with the design
investigations conducted in 1989/90.
3.1.4 Surrounding Land Uses
The footprint is surrounded by Crown land and within the Environmental Management
Zone, much of which is managed by Parks and Wildlife Service (PWS).
The State Forest either side of the D Dam footprint includes Ring River Road and Argent
Track. There is some land to the north on the opposite side of Lake Pieman and to the
south adjacent to the Murchison Highway, also managed as State Forest, which is within
the Environment Protection Zone.
Lake Pieman is used for recreational boating and fishing, mainly by locals.
The nearest residence is adjacent to the Rosebery Golf Course, along the Murchison
Highway about 5 km towards Rosebery. This property is within the Natural Resources
Zone under the West Coast Interim Planning Scheme 2013. The nearest residential or
urban properties within the Urban Zone are in Rosebery and Zeehan.
3.2 European Heritage
The site itself does not appear on any statutory or non-statutory heritage register or list. A
heritage desk study of the footprint and its surroundings was undertaken, full details of
which can be found in Appendix C.
The data examined included a preliminary cultural heritage inventory of site from October
2000, which identified 30 mining activity sites with varying levels of significance. However
these were all more than a kilometre to the south of D Dam.
42 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Advice was provided by Heritage Tasmania in July 2008 indicating that further European
Heritage studies of the D Dam footprint would not be required for this project. The 2012
review reinforced the understanding of the high significance of the broader Renison Bell
area in Tasmania’s mining history, but identified little potential for significant heritage
within Project footprint.
3.3 Aboriginal Heritage
Former site owners, Renison Bell Ltd, commissioned an audit of compliance with the
Aboriginal Relics Act 1975 in 1999. This audit (Sim and Moore, 1999) recommended that
although no Aboriginal sites were identified on the TASI database, a site survey of the
lease area should be undertaken prior to any further ground-disturbing activity.
In 2000 Becker and Sainty undertook an archaeological survey of parts of the former
Renison Bell Ltd site (now owned by BMT JV).
These two reports were submitted to Aboriginal Heritage Tasmania in 2008. A response
was provided by AHT in July 2008, stating that no further Aboriginal Surveys were
required for D Dam (see Appendix D). This was reinforced in the Project Specific
Guidelines (EPA, December 2012).
3.4 Environmental Aspects
3.4.1 Topography and Landscape
The D Dam footprint contains native forest which has been selectively logged in the past.
The topography is varied and moderately rugged, comprising a large basin bounded by
the existing TSFs to the south and west and an existing hillside adjacent to the Ring River
to the east.
The hillside rises from 100 m AHD average, at the banks of Lake Pieman, to 150 m AHD
over a distance of approximately 150 m forming a steep natural rise. The slope continues
up to 165 m AHD and then forms a level plateau which extends over approximately 200
m to the alignment of the D Dam embankment.
A minor tributary of Lake Pieman dissects the footprint, forming a steep valley in the less
disturbed central section. The base of the valley is approximately 130 m AHD near the
location of the northern embankment rising to approximately 160 m AHD near the toe of B
Dam. The eastern valley side within the D Dam footprint rises to a height above 175 m
AHD, and then slopes steeply away towards the Ring River.
Both hillsides are largely covered in native vegetation, although a borrow pit lies in the
southern section mostly within the D Dam footprint. The slope towards Lake Pieman is
relatively more gradual.
The two proposed borrow areas lie on ridges to the North and West of the existing C Dam
(see Figure 2-1).
The core of the C Dam Borrow Area sits at approximately 190 m AHD and has largely
been cleared for quarrying of materials. The western and southern parts of the borrow
areas are more densely vegetated with Nothofagus and Eucalyptus delegatensis
rainforest thickening as the slopes of the ridge descend towards Lake Pieman in the
North and the Argent River to the West.
The West Pieman Borrow Area extends from near the base of C Dam along narrow ridge
with similar vegetation to the C Dam Borrow Areas at approximately 160 m AHD to a low
point of approximately 130 m AHD.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 43
Aesthetic values are discussed further in connection with specific viewpoints in Section
4.12.
3.4.2 Meteorology
The climate of the West Coast of Tasmania is generally cool and wet and is strongly
influenced by maritime weather systems from the Southern Ocean.
Rainfall and evaporation data is collected at the Renison site. For other data the Strahan
Aerodrome meteorological station (approximately 42 km to the southwest) is the closest
to the site giving data since 1981.
Rainfall
Rainfall is well above the Australian average all year round but is particularly heavy
during the winter months. Table 3-1 provides the maximum and minimum annual rainfall
during this period.
Table 3-1 Climate Data – Rainfall (Renison 097021)
Climate Parameter Annual Rainfall (1911 – 2011) (mm)
Minimum 1662.4 (recorded in 1982)
Maximum 2939.2 (recorded in 1968)
Average 2228.4
Figure 3-1 indicates that the wettest months are May – October, however high
precipitation (rain and snow) occurs throughout the year (BMT JV, 2009).
Figure 3-1 Mean Rainfall Data Renison Bell Gauge 1911 to 2013 (BOM)
Evaporation
Evaporation was monitored at the site between July 1997 and June 2009 using a
standard Class A Pan used by the BOM (BMT JV, 2009). The findings of this monitoring
are summarised in Table 3-2 below.
0
50
100
150
200
250
300
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
44 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
The monitoring has shown that between November and March of any summer,
evaporation often exceeds rainfall. However, annually, rainfall exceeds evaporation by an
average of 1384 mm.
Table 3-2 Evaporation
Climate Parameter (Annual evaporation (1997 to 2009)
Value (mm)
Minimum 715 (recorded in 2001 to 2002)
Maximum 1,055 (recorded in 1999 to 2000)
Average 820
Temperature
Average maximum and minimum temperatures for Strahan Aerodrome are shown on
Table 3-3.
Table 3-3 Temperature (Strahan Aerodrome 097072)
Climate Parameter Value (C)
Mean maximum temperature (hottest month)
21.2 (February)
Annual mean maximum temperature 17.1
Highest maximum temperature 24.6
Mean minimum temperature (coolest month)
-1.1 (July)
Annual mean minimum temperature 5.5
Lowest minimum temperature -2.7 (21 June 2007)
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 45
Wind
The prevailing winds for Strahan are from the west and northwest. This pattern may be
less pronounced at Renison, which is further from the influence of the ocean.
Figure 3-2 Average Annual Wind Data at 3 pm for Strahan Aerodrome (097072)
3.4.3 Geology and Geomorphology
Geology
Renison Bell Tin Mine has the largest of three major, stratabound, carbonate-
replacement, pyrrhotite-cassiterite deposits found in western Tasmania (BMT JV, 2009).
The local geology comprises:
Recent deposits include lag gravels, colluvium, alluvium and peat. (Coffey 1990);
Pleistocene deposits include fluvioglacial gravels and sands, and lacustrine silts
and clays; and
Cambrian argillite and greywacke. These are steeply dipping, weakly
metamorphosed sedimentary rocks, comprising alternating beds of greywacke and
argillite of Cambrian age (Coffey, 1990). Close to the surface these are heavily
weathered.
Structural components in the area of D Dam include bedding, sheared and / or crushed
zones, joints, faults, and decomposed zones (Coffey, 1990).
46 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
The major structural feature is the bedding in both the argillite and the greywacke, which
typically strikes north – south. Bedding dips 50 to 80 degrees to the east. Bedding
partings exist; with the frequency of partings increasing in more weathered rock.
Faults typically trend northeast to southwest, and minor sets trend east – west (Coffey,
1990). Lateral continuity of these faults is unknown. Joints are generally tight, planar and
smooth or rough with limonite staining. No preferred orientation was identified in Coffey
1990 site investigations.
Geomorphology
The Natural Values Atlas shows that the Project footprint is within the Central Highlands
Cainozoic Glacial Area, which is classified as having Australian significance, with an
overall sensitivity level of 5 (with 1 being the highest). A sensitivity level of 5 is defined as
values sensitive to damage by higher intensity shallow linear impacts, depending upon
their precise position.
An area of Western Tasmania Blanket Bog lies outside the Project footprint to the south
of the existing TSFs.
A geomorphic review and survey examined if any features associated with these
designations were present within the Project footprint.
The site has been glaciated on at least two occasions during the mid-Pleistocene, during
the Bulgobac and Que Glaciations.
The assessment included the description of six sections exposed in areas previously
used for the excavation of material for construction purposes. The cuttings show various
deposits including lacustrine and glacial/fluvioglacial sediments, in some cases up to 20
m thick. Glacial erratics were also identified at the site, although these were not in-situ
and may have been moved during excavation activities.
The site has been highly modified through the cutting of tracks and the excavation of
surface sediments and bedrock for construction of tracks and dam walls. This makes the
identification of glacial landforms (such as moraines) difficult, and has left the site with
little geomorphological conservation value. However, the disturbance of the site has
allowed the relatively recent exposure of sections that are able to provide some insight
into the glacial history of the area.
Appendix E contains further details of the Geomorphic and Geoheritage Assessment.
3.4.4 Surface Water
Hydrology
The main surface water courses potentially affected by the Project and are shown on
Figure 3-3.
Argent River (flooded arm of Lake Pieman);
Ring River (flooded arm of Lake Pieman); and
Lake Pieman.
The hydrology in the area is dominated by Lake Pieman which was created by the
flooding of the Pieman River valley behind the Reece Dam. Water flows through the lake
are intermittent and controlled and hence it has intermittent, irregular flows at low
velocities. Similarly the sections of Ring River into which discharges from the existing and
proposed TSFs discharge are also flooded, essentially as extensions of Lake Pieman.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 47
The smaller streams between the TSFs and predominant receiving waters are low
volume upland creeks for which no measured flow data is available.
Water Quality
The main surface waters surrounding the D Dam footprint are Lake Pieman (north), Ring
River (east) and Argent River (west). The existing TSFs discharge decant and seepage
effluent into the following water courses:
Argent River –seepage water, overflow, and, until the end of decommissioning,
decant, from C Dam.
Lake Pieman – seepage water and storm runoff from Dams A and B;
Ring River – decant and seepage water from Dams A and B.
The surface waters surrounding the proposed dam are already subject to significant
historical mining impact migrating from upstream of the Renison site and therefore do not
represent a pristine receiving environment (as discussed in further detail below).
In compliance with EPN 7092/2, BMT JV monitors ambient water quality. Table 3-4
shows results monitoring between 2007 and 2014. These are compared to the ANZECC
95% species protection level and recreational water quality and aesthetics trigger values
as relevant to the PEVs outlined above (modified ecosystems).
Protected Environmental Values
The State Policy on Water Quality Management 1997 (SPWQM) defines Protected
Environmental Values (PEVs) as the values or uses for which a given water body should
be protected. PEVs that are relevant to this assessment cover the Ring River
downstream of Bakers Creek.
The identified PEVs have been sourced from DPIWE (now DPIPWE) document, Environmental Management Goals for Surface Waters, Catchment Within the Circular
Head & Waratah/Wynyard Municipal Areas (2000). These PEVs include the following:
A: Protection of Aquatic Ecosystems:
(ii) Protection of modified (not pristine) ecosystems
– b. From which edible fish are not harvested
Having regard for Forestry Tasmania’s ‘Management Decision Classification System.
B: Recreational Water Quality & Aesthetics:
(iii) Aesthetic water quality
As a minimum, water quality management strategies should seek to provide water of a
physical and chemical nature to support the modified aquatic ecosystems from which
edible fish may not be harvested and to maintain any aesthetic qualities of the rivers.
Bio-accumulation
There are no known data on bioaccumulation of metals in fish species in Lake Pieman.
Average water quality sampled in the Ring River or Lake Pieman does not approach the
ANZECC Recreational Water Quality and Aesthetics Guideline levels, though some
metals slightly exceed the ANZECC 95% Species Protection trigger values (see Table
3-4). ANZECC has accounted for the bioaccumulation potential of metals in the trigger
values.
48 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Therefore, the low contaminant levels within Lake Pieman upstream and downstream of
the BMT mining lease present low risk of bioaccumulation. Elevated metals further up the
Ring River catchment are unlikely to contribute to bioaccumulation in fish as this requires
prolonged exposure.
Large fish, being typically transient, would be unlikely to stay in the catchment long
enough for bioaccumulation from this source to occur and this type of pulse exposure
metal accumulation can be ameliorated by the fish’s metallothionen detoxification
enzymes. Furthermore, metals tend to bioaccumulate in the liver of fish and only to a
lesser extent in the fish flesh, further reducing the risk to human health from fish
consumption.
Water Quality Criteria
Water Quality Objectives (WQOs) are the most stringent set of water quality guidelines
which should be met to achieve all of the PEVs nominated for the body of water.
The EPA are developing Water Quality Objectives for regional waters which will form the standards taking into account regional factors including sequestration by the high organic levels observed in West Coast waters. However no specific WQOs were available at the time of issue.
In the absence of specific Water Quality Objectives set by the EPA, reference has been
made to the relevant trigger values referenced in the ANZECC & ARMCANZ (2000)
guidelines using the Lowland river objective (for systems below 150 m AHD)as the
proposed discharge is at around 130 m.
As the receiving environment is classified as a modified (not pristine) ecosystem, the 95%
species protection levels from ANZECC have been adopted (see Table 3-4) for
comparison against existing water quality.
The toxicant comparison has been based on 95% species protection trigger value which
applies to ecosystems that are modified (not pristine).
Ambient Water Quality (Baseline at Discharge point)
Ambient water quality at the discharge point is characterised by point RAR,
representative of the existing water quality as close as possible to the discharge point.
This site incorporates existing BMT JV discharges from the Isaacson Creek dams,
Crusher dams, A Dam and B Dam decants.
Overall the receiving waters (RAR) are degraded due to mining activities within and upstream of the discharge point.
The ambient water monitoring data supports this and demonstrates that several parameters are well above the ANZECC 95% Species Protection and Recreational Water Quality and Aesthetics Trigger Values.
Median concentrations of Aluminum, Cadmium, Chromium, Copper, Lead, and Zinc are well above the 95% Species Protection trigger values for site RAR. Similarly, median Aluminum, Copper, Lead and Zinc concentrations were well above the 95% Species Protection trigger values for all sites.
Ambient water quality (Background)
Background values are characterised by points (locations of which are displayed on
Figure 3-3) beyond the influence of discharges from BMT JVs operations:
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 49
PAR represents background water quality in Lake Pieman, upstream of the point
where is mixes with water from the Ring River Arm. While exceeding the 95%
species protection threshold and being far from pristine, PAR shows lower
concentrations for all parameters except magnesium than those in the Ring River
catchment (including the Ring River Arm).
RAD represents water quality in the Ring River catchment upstream of BMT JVs operations. It demonstrates the impact of historical legacy of mining on water
quality, with elevated metals (especially zinc) and very high sulphate
concentrations. The quality of the water in the Ring River improves as it flows
towards Lake Pieman and is diluted by surface water, both from inside and outside
BMT JV’s lease.
RAR represents water quality in the arm of the Ring River flooded by Lake Pieman.
It shows the zone historically (but no longer) affected by the discharges of tailings
decant from B Dam and the baseline water quality at the point where D Dam will
discharge to the Ring River. Although it shows elevated levels of contaminants
relative to Lake Pieman, nearly all are at lower levels than higher up in the
catchment. This indicates dilution by waters of Lake Pieman and surface water
runoff.
PBH represents water quality in Lake Pieman downstream of existing Renison
activities. Although some parameters are above those recorded in PAR, the water
quality is broadly similar to background.
50 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Table 3-4 Ambient Water Quality Results
PAR RAD RAR PBH Units Median Median Median Median ANZECC
95% species protection
ANZECC rec. water quality and aesthetics
Temp °C 8 11 12 9.3
pH 5.52 6.09 5.41 5.7 6.5-8.0* 5.0 - 9.0*
Cond µS/cm 72 41.1 48.8 50.8 125-2200 670 000
DO %Sat 98.7 83 85.6 81.6 85-110 -
TSS mg/L 2 1 2 2 - -
Fe Total mg/L 370 454 485 473 300
Al Total mg/L 0.281 0.368 0.285 0.286 0.055 200
As Total mg/L 0.002 0.002 0.0025 0.002 0.013 50
Cd Total mg/L 0.005 0.006 0.0005 0.0003 0.0002 5
Ca Total mg/L 0.002 0.002 0.0031 0.003 - -
Chloride mg/L 0.007 0.007 0.007 - - 400 000
Co Total mg/L 0.0005 0.006 0.5 0.0008 - -
Cr Total mg/L 0.0005 0.002 0.001 0.002 0.001 0.05
Cu Total mg/L 0.002 0.05 0.003 0.003 0.0014 1
Mg Total mg/L 0.89 0.0015 0.001 - - -
Na Total mg/L 0.0044 0.0065 0.0046 - - 300
Ni Total mg/L 0.0008 0.0024 0.001 0.0017 0.011 0.1
K Total mg/L 0.0003 0.0003 0.00036 - - -
Pb Total mg/L 0.003 0.046 0.005 0.0037 0.0034 0.05
Sulphate mg/L 0.0074 14.4 0.007 0.0057 - 400
Zn Total mg/L 0.05 2.92 0.121 0.088 0.008 5
Bold text denotes non‐compliance with ANZECC trigger for 95% species protection. None of the parameters show non‐compliance with ANZECC Recreational Water Quality and Aesthetics Guidelines. * ANZECC guidelines for pH are not generally applicable in Tasmanian Water
Trigger Values
The assessment of impacts on surface water bodies uses trigger values based on
monitored values for ambient water quality. The SPWQM states that ‘wherever practical
and appropriate, water quality guidelines should be based on site specific information
which should be used to supplement the Australian Water Quality Guidelines’ (ANZECC
2000). This is particularly relevant as significant background water quality data exist,
indicating elevated background levels of several contaminants
Table 3-5 displays the 80th percentile (20th percentile for pH) of contaminant from recent
receiving waters monitoring data of (July 2007 to June 2011). These 80th percentile
values have been adopted in the Receiving Environment Assessment as trigger values.
For comparison, the table also provides the default ANZECC & ARMCANZ (2000) trigger
values. Shading indicates the correspondence between a site specific trigger value and
the level of protection with the ANZECC & ARMCANZ (2000) trigger levels.
The final column indicates whether the site specific trigger value is greater than the
ANZECC & ARMCANZ (2000) trigger values.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 51
Lake Pieman at site PAR (see Figure 3-3) has been adopted as background for the
development of site specific trigger values.
Whilst site PAR has been adopted as background for the purposes of developing site specific trigger values the State Policy on Water Quality Management 1997 (SPWQM)
requires reasonable and practical measures to be taken to reduce pollutants at source
and the mitigation measures outlined in this DPEMP aim to achieve that goal.
52 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Table 3-5 Water Quality Trigger Values 80 Percentile Ambient Data
Parameter
All values in mg/l except pH
Lake Pieman at Site PAR
Ring River Arm - Site RAR @
Node 2
Confluence of Ring River Arm and Lake Pieman Site RMZ @ Node 9
Below Confluence of Husskinson River Arm in Lake Pieman – Site PGH @ Node 10
ANZECC & ARMCANZ (2000) Trigger Values for Percentage Level of Freshwater Species Protection
Site Specific Trigger Value above ANZECC & ARMCANZ (2000)
99% 95% 90% 80%
pH 4.95 4.64 5.14 5.20
Total Cd 0.0011 0.0023 0.0005 0.0005 0.00006 0.0002 0.0004 0.0008 Yes
Total Cr 0.0020 0.0028 0.0020 0.0020 0.00001 0.0010 0.0060 0.0400
Total Ni 0.0020 0.0044 0.0020 0.0026 0.0080 0.0110 0.0130 0.0170
Total Cu 0.004 0.020 0.006 0.004 0.001 0.0014 0.002 0.003 Yes
Total As 0.003 0.003 0.005 0.003 0.001 0.013 0.042 0.140
Diss Fe 0.58 1.22 0.68 0.67
Total Pb 0.014 0.015 0.007 0.006 0.0010 0.0034 0.0056 0.0094 Yes
Total Zn 0.20 1.27 0.19 0.16 0.0024 0.0080 0.0150 0.0310 Yes
SO4 13.8 47.1 11.5 11.1
Total Cl 8.3 10.0 8.8 10.9
Total Al 0.310 0.540 0.315 0.315
Total Ca 3.7 8.4 4.6 4.7
Total K 0.42 0.50 0.43 0.50
Total Mg 1.83 2.98 1.63 2.10
Total Na 5.34 6.67 5.51 6.25
Source BMT JV monitored between Jun 2004 and June 2011
SeepageIntercept
S2
S4
TDS3
S2
S1
AP
CR
TB
TC
RBB
RAB
RAD
AAH
RAR
PAR
RMZSMZ
AMZ
HUS
PBH
SeepageIntercept
RING001
RING002
ARGENT002
ARGENT001
ARGENT003
GW9
GW8GW7
GW6
GW5
GW15
GW14
GW13
GW12
GW11 GW10
"C" Dam
"B" Dam"A" Dam
368,000
368,000
369,000
369,000
370,000
370,000
371,000
371,000
5,371
,000
5,371
,000
5,372
,000
5,372
,000
5,373
,000
5,373
,000
5,374
,000
5,374
,000
5,375
,000
5,375
,000
N:\AU\Hobart\Projects\32\16878\GIS\Maps\3216878_3-3_Water_Sampling_Locations_RevC.mxd
© 2015. Whilst every care has been taken to prepare this map, GHD (and DPIPWE TASMAP and MRT) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason.
Figure 3-3Map Projection: Transverse MercatorHorizontal Datum: Geocentric Datum of Australia 1994
Grid: Map Grid of Australia, Zone 55
BMT JV Pty LtdRenision Bell, Tailing Storage FacilityDPEMP
Water Sampling Locations
Data source: GHD proposed D-Dam embankment extents 2011, Bluestone Mines Tasmania dam extents 2011, DPIPWE TASMAP 1:25,000 topographic map 2008, Mineral Resources Tasmania mine lease boundary 2011. Created by: AH Edited by: jtoregan, jpulford & dtickner
2 Salamanca Square Hobart TAS 7000 Australia T 61 3 6210 0600 F 61 3 6210 0601 E [email protected] W www.ghd.com
ZEEHAN(16 km)
MURCHIS
ON
HW
Y
0 100 200 300 400 500m
Scale at A4 - 1:20 000
Existing dam
Mine lease boundary
Job NumberRevision D
32-16878
Date 03 Mar 2015
ROSEBERY(11 km)
Watercourses within mining lease
Proposed borrow area
Proposed dam outline
Aquatic ecology survey locations
Monitoring site - ambient
Monitoring site - point source discharge
New monitoring site
Groundwater monitoring locations (Coffey 2013)
54 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
3.4.5 Groundwater
Various groundwater studies have been undertaken at the D Dam site, culminating in a study
involving eight groundwater monitoring wells, the locations of which are shown on Figure 3-3.
Full details of the groundwater monitoring are presented in Appendix G.
Water Quality Objectives
The State Policy on Water Quality Management 1997 (SPWQM), the peak document for
groundwater management in Tasmania, uses groundwater salinity (measured as Total
Dissolved Solids) to assess the PEVs (or beneficial uses) of a groundwater. Water of higher
quality (lower salinity) has more beneficial uses than low quality (more saline) groundwater.
Given the current and likely future site uses, the relevant beneficial uses are maintenance of
ecosystems, both aquatic and terrestrial, and primary recreational contact. Also, the SPWQM
defines Water Quality Objectives for a specific body of water as being the most stringent set of
water quality guidelines, which should be met to achieve all of the PEVs nominated for that body
of water (see Section 3.4.4).
For certain parameters, for example metals and major cations, ambient groundwater quality can
be evaluated by comparison with the most stringent limit of the following guidelines:
Freshwater aquatic ecosystems, based on ANZECC & ARMCANZ (2000) guidelines for
95% ecosystem protection for moderately disturbed ecosystems;
Primary recreational contact based on ANZECC & ARMCANZ (2000) guidelines;
Current site discharge licence requirements under EPN 7092/2.
Aquifers
There are two main aquifer systems identified within the stratigraphic sequence that are relevant
to the study, namely:
Pleistocene sediments;
Cambrian bedrock.
The Pleistocene sediments consist of gravels, silts and sands, and where gravel and sand
layers exist intergranular flow will dominate flow processes, although fissures and desiccation
cracks may also provide secondary permeability in clays. These sedimentary layers are
relatively thin (no more than 10 m) and are not laterally continuous, potentially acting as
perched aquifer systems, and / or contributing to groundwater surface seeps, with connection
with the underlying fractured rock aquifer restricted by clayey weathered rock or clayey
sediments.
Greywacke and argillite are important when considering secondary porosity. While the clayey
weathered argillite can act as an aquitard, the structural controls from bedding, stress relief
jointing, fractures and faults from the partially weathered to fresh rock have the potential to form
a relatively permeable aquifer. The structural planes may act to channel groundwater to
discharge zones, either in Lake Pieman, and or redirect groundwater to the surface. Within the
bedrock permeability decreases logarithmically
Permeability
The Cambrian bedrock is a fractured rock aquifer which stores and transmits groundwater by
fractures, joints and other discontinuities. Fracturing is typically higher near surface, where
stress-relief fracturing is abundant, decreasing with depth until only regional tectonic fracturing
is present. All permeability testing to date has been within the typical zone of stress relief
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 55
fracturing in the upper 20 m of rock. Permeability decreases logarithmically with depth from
1.5x10-5 m/d in rock exposed at surface, down to 1.5 x10-7 m/d at a depth of 20 m.
The Pleistocene sediments (e.g. fluvioglacial sediments) are highly permeable where gravels
and sands are dominant, but have relatively low permeability where clayey sediments or
weathering products are dominant. The hydraulic conductivity of the sediments ranges from 1.5
x10-6 m/d to 1.5 x10-5 m/d, with higher permeability zones present in Pleistocene sands and
gravels. The sediments are in discontinuous deposits, isolated by areas of weathered rock
outcrop and hence do not form a single aquifer.
Unconfined storage coefficients in the sediments and shallow fractured rock are likely to be
relatively high at around 0.1 to 0.2 decreasing to in the order of 0.01 in deeper fractured rock.
Groundwater Level Trends
Levels monitoring during May and September 2013 found that, groundwater responded strongly
to rainfall in GW9, GW12 and GW15, whereas levels were relatively stable over the same
period in GW7, GW8 and GW11. GW5 and GW6 show a muted response to rainfall events with
an overall increase in groundwater level over the four month period.
There is a possible trend of a more marked response in bores in more elevated areas distant
from large water bodies such as Lake Pieman (GW9, GW12 and GW15) with water levels in
bores adjacent to large water bodies controlled by the surface water level such as C Dam
(GW6, GW7, GW8) or Lake Pieman (GW11). Where water levels showed a response, they
appeared to lag approximately 1 week after rainfall.
This results in outward movement of groundwater from the TSFs to the surrounding Argent
(westward) and Ring (eastward) Rivers and Lake Pieman (northward), with local discharge to
creeks near the base of the embankments.
Monitored Groundwater Quality
Results of groundwater sampling and analysed by Coffey (2013) are presented in Appendix G
and summarised in Table 3-6.
Major ion analyses indicate that:
GW6, GW9, GW10 and GW11 share similar chemical signatures and are classified as
sodium chloride/bicarbonate type waters. This suggests they are not significantly
impacted by existing TSFs leakage and are probably indicative of background conditions;
GW7, GW8, GW12 show elevated calcium and sulphate consistent with impact from
oxidised lime buffered sulphidic tailings;
The background well GW5 (sodium sulphate type water) is chemically distinct from the
bores at the down gradient from the TSFs.
All borehole samples indicated major ions within stock watering limits (taken as a proxy
for native terrestrial fauna), with the exception of sulphate in the bores adjacent to the
TSF embankments (GW7, GW8) or the plant (GW15). Similarly, sulphate exceeded the
recreational guideline in GW7, GW8, GW12 and GW15. All groundwater sulphate (the
only referenced major ion) concentrations, however, were within the site release limits for
A, B and C dams (EPN 7092/2)
56 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Metals analyses indicated the following exceedances:
Background bores GW10 and GW11 exceeded ANZECC & ARMCANZ (2000) freshwater
aquatic ecosystem guideline for the protection of 95% of species (FAE95%) for
chromium1 nickel and zinc;
Other bores also contained similar levels of these metals, with the addition of
exceedances for cadmium and copper. This suggests chromium, nickel and zinc are
naturally elevated, but that seepage from TSFs and other mine operations may have
resulted in cadmium and zinc contamination of groundwater;
All metal concentrations were within available stock watering guidelines (ANZECC &
ARMCANZ 2000);
Recreation guidelines were exceeded by one or more of arsenic, iron, manganese and
nickel in some bores. Arsenic guidelines were not exceeded in bores surrounding the
TSFs or in the proposed D Dam area.
Metals were within site release limits for A, B and C Dams (EPN 7092/2) with the exception of:
Iron in GW 7 and GW8;
Nickel and zinc in the seepage sample S1 (GHD 2001).
Based on the elevated water levels and elevated metals and sulphate in seepages and
groundwater around the TSFs, leakage of liquor and leachate beneath the TSFs has resulted in
mounding of contaminated groundwater beneath the TSFs albeit at concentrations within limits
set out in EPN 7092/2. Given its location this is not likely to be affecting drinking water
abstractions, livestock watering or ecological receptors.
Nutrients
Nitrate concentrations in GW6 and GW12 exceeded FAE95 for nitrate. All other bores were
within the available guidelines. The lack of significant nitrate in bores down gradient from TSFs,
suggest that it is not related to TSF operation but more likely to be the result of landfilling
operations near these bores.
TSF Seepage
Table 2-1 shows data monitored at seepage collection points in the embankment toe drains
between 1994 and 2014. Locations of seeps monitoring are shown on Figure 3-3.
Based on the elevated water levels and elevated metals and sulphate in seepages and
groundwater around the TSFs, leakage of liquor and leachate beneath the TSFs has resulted in
mounding of contaminated groundwater beneath the existing TSFs, albeit at concentrations
within limits set out in EPN 7092/2. Full data is presented in the appendices of the geochemical
report (see Appendix H).
This results in outward movement of groundwater from the TSFs to the surrounding Argent
(westward) and Ring (eastward) Rivers and Lake Pieman (northward), with local discharge to
creeks near the base of the embankments.
Characteristics of seeps over the period are relatively constant overall, though with a large
range of values resulting from short term fluctuations.
1 Assuming it was in the form of CrVI
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 57
Table 3-6 Groundwater Quality Test Results (Coffey, 2013)
Location Date Measured
Dissolved Oxygen
Conductivity (µS/cm)
Redox (mV)
pH TDS (mg/L)*
Temp (oC) Water Colour Turbidity
GW5
2/05/2013 2 407 188 5.01 264.55 12 Grey Extremely Turbid
3/09/2013 4.84 458 120 5.52 298 11.2 Grey with some sediment
Very Turbid
GW6 2/05/2013 6.46 49 210 4.89 31.85 10 Red - brown Extremely Turbid
3/09/2013 8.2 69 182 4.21 45 10 Light brown with sediment
Extremely Turbid
GW7 2/05/2013 2.38 2440 20 6.12 1586 11.8 Colourless Clear 3/09/2013 2.4 2340 20 6.1 1521 11.7 Clear Clean
GW8 2/05/2013 1.81 2420 41 6.24 1573 12.3 Orange - brown Slightly Turbid
3/09/2013 2.05 2330 28 5.97 1515 11.3 Light orange Slightly Turbid
GW9 2/05/2013 5.61 69 157 4.79 44.85 10.7 Grey - brown Slightly Turbid
3/09/2013 7.32 54 295 4.22 35 11.5 Brown Very Turbid
GW10 2/05/2013 0 0 0 0 0 0 - Extremely Turbid
3/09/2013 1.99 165 77 5.72 107 11 Grey Extremely Turbid
GW11 2/05/2013 2.39 112 46 5.57 72.8 11.4 Grey Extremely Turbid
3/09/2013 3.24 67 96 5.54 44 10.7 Grey Extremely Turbid
GW12 2/05/2013 3.61 1129 209 5.01 733.85 12.4 Orange - brown Slightly Turbid
4/09/2013 4.2 1025 383 4.32 666 13.5 Light brown Slightly Turbid
GW15 3/05/2013 4.1 2510 324 4.01 1631.5 12.2 Orange - brown Very Turbid
58 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
3.5 Terrestrial Ecology
The ecological assessment (see Appendix I) examines impacts on ecological values,
including an assessment of EPBC Protected Matters, from the construction and operation
of the Project. It includes:
Desk study assessment of Natural Values Atlas and Protected Matters Search Tool
(See Appendix K and Appendix L);
Botanical Survey and Fauna Habitat Assessment in June 2008;
Follow-up targeted threatened fauna habitat assessment in May 2011;
Vegetation and fauna habitat survey of dam footprint and borrow areas in
November 2013;
DPIPWE Helicopter survey for wedge tailed eagles;
Den searches, habitat assessment and camera survey for Tasmanian devils and
quolls (Nick Mooney) November 2013; and
Call-playback survey for Tasmanian masked owl November 2013.
This section summarises the results of the ecological studies and Section 5 provides a
tabulated summary of assessment of impact for species listed under the Commonwealth
EPBCA. The ecological survey covered the areas shown in full including the borrow area
s as well as the TSF.
The covered the areas shown in full extent of the borrow areas as well as TSF.
3.5.1 Protected Areas
The site, along with the rest of the BMT Lease area is in the Renison Bell Regional
Reserve. Enacted under the Nature Conservation Act 2002, the area was designated as
a Regional Reserve in 2012.
The designation is specific to areas of mineral exploration and is aimed at allowing
development of mineral deposits while protecting and maintaining its natural and cultural
values.
The LIST and the Natural Values Atlas databases showed two public reserves within 500
m of the site:
A Timber Reserve covering approximately one third of the D Dam footprint
(governed by the Crown Lands Act 1976);
A State Forest Reserve to the east of the site (governed by the Forestry Act 1920).
There are no private or private timber reserves within 500 m D Dam footprint.
3.5.2 Terrestrial Flora
Vegetation Communities
Thirteen native vegetation communities (including one threatened community) and four
other modified, agricultural, urban and/or exotic communities were identified within the
Project footprint (see Figure 3-4):
Freshwater aquatic sedgeland and rushland (ASF), which is listed as a
threatened community under State legislation;
Acacia dealbata forest (NAD);
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 59
Acacia melanoxylon swamp forest (NAF);
Acacia melanoxylon forest on rises (NAR);
Leptospermum scoparium – Acacia mucronata forest (NLA);
Nothofagus – Phyllocladus short rainforest (RMS);
Nothofagus – Atherosperma rainforest (RMT);
Melaleuca squarrosa scrub (SMR);
Eucalyptus delegatensis forest over rainforest (WDR);
Eucalyptus nitida forest over Leptospermum (WNL);
Eucalyptus nitida forest over rainforest (WNR);
Eucalyptus obliqua forest with broad-leaf shrubs (WOB);
Eucalyptus obliqua forest over rainforest (WOR).
Threatened Species
Of the four threatened flora species predicted to occur by desktop research within 5 km of
the Project, none were found within the Project footprint during the 2008, 2011 or 2013
surveys.
Weeds and Pathogens
The Project footprint is dominated by native species; however, a number of introduced
species were recorded (See Figure 3-4) including the following declared weeds species:
Genista monspessulana (Montpellier broom);
Rubus fruticosus aggregate (blackberry); and
Ulex europaeus (gorse).
The plant pathogen commonly known as dieback or root-rot fungus, Phytophthora
cinnamomi, is a soil borne fungal pathogen that invades the roots of plants and starves
them of nutrients and water. Heath communities are the most susceptible to infection, due
to their location in areas of low nutrient soils, high rainfall (above 600 mm per annum) and
altitude (below 800 m). These conditions are conducive to the growth and spread of the
pathogen, with subsequent loss of species abundance and diversity. The movement of
soil on vehicles, construction machinery and walking boots generally spreads the
pathogen. The pathogen is distributed extensively on the west coast of Tasmania; however, no direct evidence of P. cinnamomi was observed in the Project footprint.
3.5.3 Terrestrial Fauna
General Fauna Habitat
Fauna habitat features identified during the survey are shown on Figure 3-5.
The Project footprint topography ranges from steep slopes and gullies to flatter sections.
It contains a range of fauna habitats, including wet eucalypt forest, rainforest, scrub,
riparian habitat and a large number of old-growth hollow-bearing trees.
The wet eucalypt forest, rainforest and scrub provides potential habitat for large and small
mammals, with evidence of small layups and burrows within and amongst the decaying
logs and other vegetative matter seen during the field survey(s). The follow-up targeted
survey in 2011 recorded a large number of layups, including potential dens, within the
60 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Project footprint. However a follow-up survey of these holes by Nick Mooney in 2013
discounted all but a few of these holes as potential dens and identified no active dens in
the footprint.
The project footprint provides habitat for arboreal mammals and birds, and the presence
of large, hollow bearing trees provides potential nesting habitat for large birds, such as
eagles and owls.
Listed Fauna Identified by Desktop Study
According to the NVA Report2, no threatened fauna have previously been recorded within
500 m of the Project footprint. However, listed fauna species have been recorded, or are
predicted to occur based on habitat mapping, within 5 km of the site according to the NVA
and PMST3 reports. These species (except listed marine and migratory marine species)
and their likelihood of occurrence within the Project footprint are shown in Table 3-7.
Table 3-7 Listed Fauna Known or Predicted Within 5 km of the Project Footprint
Species Tasmanian TSP Act Status
Commonwealth EPBC Act Status
Brief habitat description & Likelihood of occurrence within Project footprint
Mammals
Dasyurus maculatus subsp. maculatus spotted-tailed quoll
Rare Vulnerable Most commonly inhabit cool temperate rainforest, wet sclerophyll forest, and coastal scrub. Likely present. Scats of a quoll (confirmed by analysis) recorded within the Project footprint are most likely from this species, with many too large to have been deposited by the smaller, non-threatened eastern quoll (Dasyurus viverrinus).
Sarcophilus harrisii Tasmanian devil
Endangered Endangered May occur in a variety of forest types including coastal heath, open dry sclerophyll forest, and mixed sclerophyll rainforest. Present, recorded during the targeted fauna survey(s).
Birds
Accipiter novaehollandiae grey goshawk
Endangered Not Listed Occurs in closed forests, with high priority nesting habitat along waterways with blackwoods. May otherwise nest in melaleuca, myrtle, teatree and eucalypt species, occasionally up to 100 m from a waterway. Possible, previously recorded within 5 km, and some suitable foraging habitat and trees suitable for nesting occur within the Project footprint.
Aquila audax subsp. fleayi wedge-tailed eagle
Endangered Endangered Nest in old growth trees, and common in areas with a mosaic of forest, farmland and waterways. Present, detected during targeted fauna survey(s) just outside the Project footprint, and previously observed overflying the area (David Lane, BMT JV, pers. comm.).
2 BCB, 2013: Natural Values Atlas. DPIPWE. Available online at: https://www.naturalvaluesatlas.tas.gov.au (accessed
24/10/13). 3 Australian Government, 2013: Protected Matters Search Tool. DOTE. Available online at:
http://www.environment.gov.au/epbc/pmst/index.html (accessed 24/10/13).
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 61
Species Tasmanian TSP Act Status
Commonwealth EPBC Act Status
Brief habitat description & Likelihood of occurrence within Project footprint A nest was recorded just over 5 km NW of the Project footprint in 2009 (PCAB 2011); however, no nests were detected during the more recent aerial survey.
Ardea alba great egret
Not Listed Migratory Found in areas with (preferably) shallow, flowing water. Can also occur in damp grasslands. Unlikely, lack of suitable habitat.
Ardea ibis cattle egret
Not Listed Migratory Prefer pasture among grazing stock, especially in poor drainage areas, and are sometimes found in shallow wetlands. Unlikely, lack of suitable habitat.
Botaurus poiciloptilus Australasian bittern
Not Listed Endangered Mainly occurs in densely vegetated freshwater wetlands and, rarely, in estuaries or tidal wetlands. Formerly widespread in Tasmania, now appears confined to coastal regions in the northeast and on the Bass Strait islands. Unlikely, although some suitable habitat, the Project footprint is outside of the species’ known range.
Ceyx azureus subsp. diemenensis azure kingfisher
Endangered Endangered Inhabits thick vegetation surrounding freshwater rivers, lakes, billabongs and swamps. Present, detected during the field survey immediately outside of the project footprint. Considered likely to forage within the Project footprint, although no suitable nesting/burrow habitat recorded.
Gallinago hardwickii Latham’s snipe
Not Listed Migratory Occurs in permanent and ephemeral wetlands, usually in open freshwater wetlands with low, dense vegetation such as swamps, flooded grasslands or heathlands, around bogs and other waterbodies; however, can also occur in saline or brackish water, and in modified or artificial habitats. Possible, some suitable habitat.
Haliaeetus leucogaster white-bellied sea-eagle
Vulnerable Migratory Generally nest and forage near the coast; however, also occur near large rivers and inland lakes. Require old growth trees for nesting. Possible, not detected during the targeted fauna survey(s) but may overfly the project footprint, which occurs close to Lake Pieman.
Hirundapus caudacutus white-throated needletail
Not Listed Migratory In Australia this species is almost entirely aerial. Occurs most often above wooded areas and heathland, but can occur over farmland and remnant vegetation at the edge of paddocks. Possible, may overfly the site.
Lathamus discolor swift parrot
Endangered Endangered Feed on the nectar of Eucalyptus globulus and E. ovata. Nest in tree hollows in eastern Tasmania, usually near the coast in dry forests. Unlikely, lack of suitable habitat and outside of normal range.
Myiagra Not Listed Migratory Inhabit heavily vegetated gullies,
62 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Species Tasmanian TSP Act Status
Commonwealth EPBC Act Status
Brief habitat description & Likelihood of occurrence within Project footprint
cyanoleuca satin flycatcher
generally in eucalypt dominated forests and taller woodlands near wetlands or waterways, although can occur in coastal or drier woodlands and open forests. Widespread in eastern Tasmania through to a line joining Ulverstone and South Cape, though also recorded further west along the north coast and in the northwest, and at scattered sites near the west coast. Possible, some suitable habitat.
Tyto novaehollandiae subsp. castanops masked owl (Tasmanian)
Endangered Vulnerable Usually found in lowland dry sclerophyll forest; however, can occur in wet sclerophyll forest, non-eucalypt dominated forest, scrub and urban environments. Possible, some suitable habitat although not detected during targeted fauna survey(s).
Reptiles
Pseudemoia pagenstecheri tussock skink
Vulnerable Not Listed Restricted to lowland tussock grassland and woodland, with a good cover of medium to tall tussocks. Unlikely, lack of suitable habitat.
Fish and Amphibians
Litoria raniformis green and gold frog
Vulnerable Vulnerable Occurs in permanent or temporary water bodies, generally dominated by Triglochin or a species of Juncus or sedge. Unlikely as outside known range.
Note: Likelihood of occurrence of threatened fauna is assessed on a four tier scale:
1. Present - individuals recorded within the Project footprint during the field assessment or any previous assessment within the boundaries of Project footprint;
2. Possible - suitable habitat occurs within the Project footprint;
3. Unlikely - suitable habitat unlikely to occur within the Project footprint, or suitable habitat substantially modified, or suitable habitat present but species not recorded for over 50 years within 5 km of the site;
4. Highly unlikely - no suitable habitat present or individuals recorded within the Project footprint, during current or any previous assessment.
3.5.4 Listed Fauna Survey results
Tasmanian devil and Spotted-tailed Quoll
Although 60 potential dens were identified in a preliminary survey, a more detailed
assessment by Nick Mooney discounted the majority of these as potential dens, although
30 had potential for use as lay-ups and four as potential social dens. In additional an area
comprised of a complex of logs and boulders was considered by Nick Mooney to have
potential for a natal den although none was present.
No active or natal dens were recorded.
The devil survey counted two fresh scats per kilometre over two kilometre of track
probable devil scats (without green algae but very consistent in form with devil scats).
Four or Five Tasmanian devils recorded on 12 camera traps over 5 nights, only on one
night each, suggesting irregular use of the area by multiple devils and a very low density
of devils within the Project footprint.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 63
The lack of multiple records of the same devil(s) suggests devils using the mine had very
large home ranges (i.e. were at very low densities and may not have visited the site very
frequently). The number of devils recorded suggests a minimum using the area at least
occasionally and no dependent young were recorded.
Although Devil Facial Tumour Disease (DFTD) has not yet been detected in this
immediate region of Tasmania, ‘it has been recorded north and south of the mine and
slightly west’ (DPIPWE 2012). No devils recorded during the camera survey were
exhibiting visual symptoms of DFTD but the sample was small and early stage lesions are
very hard to detect via cameras.
The assessment also indicated the presence of feral cats and dogs as competition and
low prey abundance as being indicative of low devil and quoll densities.
It is also possible the spotted-tailed quoll, listed as vulnerable under the EPBC Act and
rare under the TSP Act, occurs within the Project footprint. Quoll scats (confirmed by
analysis) were recorded during the field survey with many considered too large to have
been deposited by the smaller, non-threatened eastern quoll (Dasyurus viverrinus).
However, no quolls were recorded on any of the cameras deployed during the survey
periods, suggesting a low local abundance.
Tasmanian Masked Owl
Surveys in 2011 and 2013 identified potential foraging habitat for the Tasmanian masked
owl, with forests, woodland and adjacent open country providing habitat for potential prey
species within the project footprint. A large number of trees with hollows of a suitable size
for nesting were also recorded during the field survey.
No individuals were detected during three nights of targeted play call back surveys by
GHD staff. Nick Mooney’s opportunistic searches for specific signs of masked owls
observed no evidence of their presence. Masked owl behaviour is known to be cryptic
and there remains some possibility that this species may nest within the Project footprint;
however, based on evidence obtained it is considered unlikely the project footprint
provides critical habitat for the species.
Azure Kingfisher
This species was detected (heard) along a waterway just outside the project footprint,
east of the West Pieman Ridge Borrow footprint. This indicates the species is present in
the region and it is considered likely that this species forages within the project footprint,
although no suitable nesting/burrow habitat was recorded within the footprint.
Azure kingfisher nests in burrows in the wooded margins of large river systems (Parks
and Wildlife (DPIPWE, 2012). It requires earth banks for nesting which are likely to be
provided in the margins of Lake Pieman and the flooded arms of adjoining creeks
downstream of the site.
No such optimal breeding habitat was identified within the project footprint. The
surrounding environment (outside of the project footprint) does provide potential breeding
habitat along the margins of the Ring River and/or Lake Pieman although no burrows
were identified. The location of the proposed end of the decant pipe on the Ring River
may provide breeding habitat for the species, although no calls were heard during call
play back and no evidence of burrows was found at this site.
Despite a lack of suitable breeding habitat within the direct project footprint, the site does
provide potential foraging habitat (approximately 9 ha).
64 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Location of the recorded azure kingfisher (heard) and call play back survey point are
shown in the Botanical Survey and Fauna Habitat Assessment Report (Appendix I).
The creek lines immediately downstream of the Project footprint were identified as only
foraging habitat for azure kingfisher.
Wedge-Tailed Eagle & White-Bellied Sea-eagle
The wedge-tailed eagle has been previously observed overflying the site (David Lane,
BMT JV, pers. comm.), which contains a number of trees of a suitable size for nesting. A
suspected eagle nest was recorded within the vicinity of the site in 2001 (Thompson and
Brett, 2004). A search to confirm the presence of this nest was conducted via aerial
survey in 2005 by Bill Brown (Threatened Eagles Officer, DPIW), the results of which
indicated no nest was present within the vicinity of the proposed dam (email dated 8
February 2005).
GHD contacted Bill Brown in 2008, who confirmed that the results of this survey were still
valid (email dated 16 July 2008). An eagle nest was recorded just over 5 km northwest of
the Project footprint in the NVA report generated at the time (see PCAB 2011).
No new nests were recorded during the 2012 aerial survey targeting these species, and
none were detected within the Project footprint. It is therefore considered unlikely that an
eagle nest currently occurs within the Project footprint, although potential nesting habitat
is present.
Three wedge-tailed eagle individuals were detected just outside the Project footprint
during the aerial survey, and it is considered likely this species would utilise the Project
footprint and its surroundings for foraging.
No white bellied sea eagles were recorded in the survey and no there is no previous
record of the species in the area. As discussed in Appendix I, although primarily a
coastal bird, the sea-eagle is attracted to large areas of open water (larger rivers,
swamps, lakes, the sea) and can be found inland. Therefore Lake Pieman downstream of
the Project footprint may provide foraging habitat for the species.
Grey Goshawk
Surveys in 2011 and 2013 identified habitat suitable for this species. The project footprint contains numerous Acacia melanoxylon (blackwood) trees, including old growth
individuals and, as well as being in close proximity to Lake Pieman, has numerous
waterways running through it.
It is therefore possible this species may utilise parts of the footprint for nesting and/or
foraging, with priority habitat for the grey goshawk.
The raptor survey did not detect any nesting or foraging grey goshawks. None were
detected by Nick Mooney or GHD during their opportunistic searches, which were
conducted during the courting season. It is therefore considered unlikely that active
breeding is currently taking place within the project footprint.
Other Potential Threatened Species
A further three threatened fauna species were identified as potentially occurring on site
based on habitat values:
Latham’s snipe – while the project footprint may provide foraging habitat for this
species, it does not breed within Australian jurisdiction. In addition, potential habitat
for this species was generally of poor quality (modified ASF community), and is not
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 65
considered likely to be providing critical habitat for the species. No evidence of the
species was detected during the site surveys;
White-throated needletail – this species is widespread throughout Tasmania and
may forage within the Project footprint, but does not breed in Australia. No
evidence of the species was detected during the site surveys;
Satin flycatcher – native vegetation within the Project footprint provides potential
habitat for this species, which nest in the outer fork of trees such as paperbarks,
eucalypts and banksias, and return to the same locality each year. No evidence of
the species was detected during the site surveys.
3.5.5 Non Threatened Fauna Species
Table 3-8 lists non-threatened fauna species identified on site.
Feral Animals
Feral and stray dogs and cats are known to occur within the Project footprint, and
anecdotally are understood to regularly scavenge at the waste disposal facility close to D
Dam. These animals are likely to compete with the threatened fauna species for food,
and may prey upon their young.
66 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Table 3-8 Non-threatened Native Fauna Recorded During Survey
Common Name Scientific Name Record Type* Mammals
Swamp Antechinus Antechinus minimus P
Dusky Antechinus (probable) Antechinus sp. (probably A. swainsonii) P
Long-nosed Potoroo Potorous tridactylus Scat
Common Ringtail Possum Pseudocheirus peregrinus Scat/Drey/P
Long-tailed Mouse Pseudomys higginsi P
Swamp (Velvet-furred) Rat Rattus lutreolus P/C
Short-beaked Echidna Tachyglossus aculeatus Scat/C
Tasmanian Pademelon Thylogale billardierii S/P/C
Common Brushtail Possum Trichosurus vulpecula Scat/P/C
Birds
Tasmanian Thornbill Acanthiza ewingii H/S
Brown Thornbill Acanthiza pusilla H/S
Eastern Spinebill Acanthorhynchus tenuirostris H/S
Australian Owlet-nightjar Aegotheles cristatus H
Fan-tailed Cuckoo Cacomantis flabelliformis H
Yellow-tailed Black-cockatoo Calyptorhynchus funereus H/S
Scrubtit Canthornis magna H/S
Australian Wood Duck Chenonetta jubata H
Shining Bronze-cuckoo Chrysococcyx lucidus H
Grey Shrike-thrush Colluricincla harmonica H/S
Black-faced Cuckoo-shrike Coracina novaehollandiae H/S
Forest Raven Corvus tasmanicus H/S
Pallid Cuckoo Cuculus pallidus H
Black-fronted Dotterel Elseyornis melanops S
Tree Martin Hirundo nigricans H/S
Yellow-throated Honeyeater Lichenostomus flavicollis H/S
Superb Fairy-wren Malurus cyaneus H/S
Southern Boobook Ninox novaeseelandiae H
Olive Whistler Pachycephala olivacea H/S
Golden Whistler Pachycephala pectoralis H/S
Spotted Pardalote Pardalotus punctatus H
Pink Robin Petroica rodinogaster S
Common Bronzewing Phaps chalcoptera H
Brush Bronzewing Phaps elegans H/S
Crescent Honeyeater Phylidonyris pyrrhoptera H
Green Rosella Platycercus caledonicus H/S/C
Grey Fantail Rhipidura fuliginosa H/S
Tasmanian Scrubwren Sericornis humilis H/S
Beautiful Firetail Stagonopleura bella H
Black Currawong Strepera fuliginosa H/S/C
Grey Currawong Strepera versicolor H
Bassian Thrush Zoothera lunulata C
Frogs
Tasmanian Froglet Crinia tasmaniensis H
Common Froglet Crinia signifera H
Southern Brown Tree Frog Litoria ewingi H
Reptiles
Tiger/ Lowland Copperhead Snake Notechis scutatus; or Austrelaps superbus S
* H – Heard; S – Seen; C – Camera, P – Prey species detected during analysis of carnivore scats.
R I N G R I V E R
L A K E P I E M A N
C-Dam Borrow
West Pieman Ridge Borrow
D Dam Footprint
"C" Dam
"B" Dam"A" Dam
369,000
369,000
369,500
369,500
370,000
370,000
370,500
370,500
371,000
371,000
5,372
,000
5,372
,000
5,372
,500
5,372
,500
5,373
,000
5,373
,000
5,373
,500
5,373
,500
5,374
,000
5,374
,000
5,374
,500
5,374
,500
G:\32\16878\GIS\Maps\3216878_3-4_Veg_Comms_RevD.mxd
0 100 200 300 400 50050m
Map Projection: Transverse MercatorHorizontal Datum: GDA 1994Grid: GDA 1994 MGA Zone 55
© 2015. Whilst every care has been taken to prepare this map, GHD (and DPIPWE TASMAP and theLIST) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason.
Bluestone Mines Tasmania Pty LtdDPEMP
Figure 3-4
Job NumberRevision D
32-16878
03 Mar 2015
Vegetation Commmunities Habitat Data in the Project Footprint
Date
Data source: GHD proposed D-Dam embankment extents, borrow areas, ecological locations, sediments, tracks, contours (derived from SRTM DEM 4.1 2008) 2011, Bluestone Mines Tasmania dam extents 2011, DPIPWE TASMAP aerial photography 2011, DPIPWE theLIST waterways and cadastre 2011. Created by: jtoregan
2 Salamanca Square Hobart TAS 7000 Australia T 61 3 6210 0600 F 61 3 6210 0601 E [email protected] W www.ghd.com
Property Boundary (approx.)
Existing Dam
Proposed Borrow Area
Proposed Dam Outline
Drainage Line
Decant Drainage Line
1:10,000Scale at A3 -
Declared Weeds
ASF Fresh water aquatic sedgeland andrushland
Vegetation Communities (TASVEG)
Wet Eucalypt forest and woodland
WDR Eucalyptus delegatensis over rainforest
WOB Eucalyptus obliqua forest with broad-leafshrubs
WOR Eucalyptus obliqua forest over rainforest
WOL Eucalyptus obliqua forest overLeptospermum
WNR Eucalyptus nitida forest over rainforest
Rainforest and related scrub
RMT Nothofagus - Atherosperma rainforest
RMS Nothofagus / Phyllocladus short rainforest
Non-Eucalypt Forest and Woodland
NAD Acacia dealbata forest
NAF Acacia melanoxylon swamp forest
NAR Acacia melanoxylon forest on rises
NLA Leptospermum scoparium-Acaciamucronata forest
Saltmarsh and Wetland
Scrub, heathland and coastal complexes
SMR Melaleuca squarrosa scrub
Agricultural, Urban and Exotic Vegetation
FRG Regenerating cleared land
FWU Weed infestation
FUM Extra-urban miscellaneous
Other Natural Environments
OAQ Water, sea
Genista monspessulana (canary broom)
Pinus radiata (radiata pine - not declared but priority for control)
Rubus spp. agg. (blackberry)
Ulex europaeus (gorse)
R I N G R I V E R
L A K E P I E M A N
D Dam Footprint
C-Dam Borrow
West Pieman Ridge Borrow
TS-8
TS-7
TS-4
TS-3
TS-2
TS-1
TS-12
TS-9
TS-5
TS-13
TS-11
TS-10
29 - 5
29 - 4
29 - 3
29 - 2
29 - 1
28 - 3
28 - 1
27 - 3
27 - 227 - 1
26 - 4
26 - 3
26 - 2
26 - 1
"C" Dam
"B" Dam"A" Dam
369,000
369,000
369,500
369,500
370,000
370,000
370,500
370,500
371,000
371,000
5,372
,500
5,372
,500
5,373
,000
5,373
,000
5,373
,500
5,373
,500
5,374
,000
5,374
,000
5,374
,500
5,374
,500
G:\32\16878\GIS\Maps\3216878_06_FaunaHabitatQuality_RevH.mxd
0 100 200 300 400 50050
Metres
Map Projection: Transverse MercatorHorizontal Datum: GDA 1994Grid: GDA 1994 MGA Zone 55
© 2015. Whilst every care has been taken to prepare this map, GHD (and DPIPWE TASMAP and theLIST) make no representations or warranties about its accuracy, reliability, completeness or suitability for any particular purpose and cannot accept liability and responsibility of any kind (whether in contract, tort or otherwise) for any expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred by any party as a result of the map being inaccurate, incomplete or unsuitable in any way and for any reason.
Bluestone Mines Tasmania Pty LtdEcological Assessment
Key Fauna Habitat Values Observed in Study Area Figure 3-5
Job NumberRevision H
32-16878
03 Mar 2015Date
Data source: GHD proposed D-Dam embankment extents, borrow areas, ecological locations, sediments, tracks, contours (derived from SRTM DEM 4.1 2008) 2011, Bluestone Mines Tasmania dam extents 2011, DPIPWE TASMAP aerial photography 2011, DPIPWE theLIST waterways and cadastre 2011. Created by: jpulford, updated by: jtoregan
2 Salamanca Square Hobart TAS 7000 Australia T 61 3 6210 0600 F 61 3 6210 0601 E [email protected] W www.ghd.com
Paper Size A3
LEGEND
D Dam Footprint
Proposed Borrow Area
Existing Dam
Combined Species Habitat Quality
High Quality Potential Habitat
Medium Quality Potential Habitat
Lower Quality Potential Habitat
Limited Habitat Value
Key Fauna Habitat
Log and boulder complex
Habitat Log
Common Ringtail Possum Drey
Hollow Bearing Tree
Threatened Fauna
Azure Kingfisher - heard
Quoll - Scat (confirmed by analysis)
Tasmanian Devil - Print
Tasmanian Devil - Scat (confirmed by analysis)
Whitewash - potentially from threatened raptor
Survey Location
Call Playback Location - Masked Owl Targeted
Listening Survey Location - Azure Kingfisher Targeted
Camera Survey Location - Tasmanian Devil Targeted
Tasmanian Devil not observed
Tasmanian Devil observed (1 individual)
Tasmanian Devil observed (2 individuals)
Devil Survey Transect
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 69
3.6 Aquatic Ecology
3.6.1 Threatened Species Predicted by Desktop Research
The NVA search described in Section 3.5.3 also listed aquatic species known or
predicted to occur within 5 km of the Project footprint. Their potential presence on site is
described in Table 3-9.
Table 3-9 Listed Aquatic Fauna Known or Predicted Within 5 km of the Project Footprint
Species Tasmanian TSP Act Status
Commonwealth EPBC Act Status
Brief habitat description & Likelihood of occurrence within Project footprint
Fish
Prototroctes maraena Australian grayling
Vulnerable Vulnerable Occurs in middle to lower reaches of rivers and streams. Unlikely, lack of suitable habitat and waterways do not flow to the coast.
Invertebrates
Beddomeia zeehanensis Zeehan freshwater snail
Rare Not Listed Native vegetation along freshwater streams provides habitat for this species, which is known from a Little Henty River tributary on Zeehan Road. The Little Henty River is considered a key site for this freshwater snail. Unlikely Not encountered in waters with less than neutral pH.
Phrantela conica hydrobiid snail (Little Henty River)
Rare Not Listed Similar habitat to Beddomeia zeehanensis but on Zeehan river. Unlikely Not encountered in waters with less than neutral pH.
3.6.2 Aquatic Invertebrates and River Health
AUSRIVAS
AUSRIVAS is a process where assemblages of aquatic invertebrates observed at a site are compared with those expected from a reference and the difference used to grade the water system in terms of ecological health in five bands:
Richer than expected (X);
Unimpaired (A);
Slightly impaired (B);
Impaired (C);
Severely impaired (D).
Historic Data
DPIPWE provided AUSRIVAS data from 1994 to 1997 for three sites on the Argent River, three sites on the Ring River, and one site downstream of the Reece Dam.
The data provided, as summarised in Table 3-10 and Table 3-11 were sampled on the Ring River are upstream of the proposed discharge point.
Although, the monitoring frequency is relatively inconsistent, the data provides a description of the Ring Catchment and indicates that the Ring River is a largely disturbed
70 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
catchment. The highest river health rating for the Ring River is above the confluence with Bakers Creek. During spring and autumn, sampling events in 1997 at this site returned a river health rating ‘B’ (0.73) and ‘A’ (0.93) respectively.
However, immediately downstream of the confluence, the river health rating declined markedly to ‘D’ (0.2) and ‘B’ (0.59) for the same spring and autumn period. This result indicates that the inputs in the region of Bakers Creeks are potentially having a detrimental impact on the ecological health of the Ring River.
Where the Ring River intersects the Murchison Highway, the river health rating for edge
habitat was consistently rated as ‘B’ while Riffle habitat fluctuated between ‘B’ and ‘C’
during this period. These scores indicate that the Ring River is slightly impaired at this
site.
Table 3-10 AUSRIVAS Data for the Ring and Argent Rivers 1994-97
Easting Northing Name Season Habitat OE50 River Health Rating
Ring River
375427 5367762 Ring River above Bakers Ck.
Spring 1997 Riffle 0.73 B
Autumn 1997 Riffle 0.93 A
375355 5367732 Ring River below Bakers Ck.
Spring 1997 Riffle 0.2 D
Autumn 1997 Riffle 0.59 B
371185 5371424 Ring River at Murchison Highway
Autumn 1996 Edgewater 0.52 B
Autumn 1996 Riffle 0.43 C
Spring 1995 Edgewater 0.7 B
Spring 1995 Riffle 0.46 C
Autumn 1995 Riffle 0.32 C
Spring 1994 Edgewater 0.49 B
Spring 1994 Riffle 0.64 B
Argent River
368339 5370309 Argent River at Murchison Highway
Autumn 1995 Edgewater 1.01 A
Autumn 1995 Riffle 0.66 B
Autumn 1996 Edgewater 0.88 A
Autumn 1996 Riffle 0.99 A
Spring 1994 Edgewater 1.09 A
Spring 1994 Riffle 0.95 A
Spring 1995 Edgewater 0.89 A
Spring 1995 Riffle 0.79 B
369115 5372080 Argent River Below Renison Town
Autumn 1997 Edgewater 0.52 B
Autumn 1997 Riffle 0.29 D
Spring 1997 Edgewater 0.95 A
Spring 1997 Riffle 0.35 C
368642 5373696 Argent River below Renison Bell Tin Mine
Autumn 1997 Edgewater 0.42 C
Autumn 1997 Riffle 0.15 D
Spring 1997 Edgewater 0.5 B
Spring 1997 Riffle 0.13 D
Results of monitoring sites on the Argent River at the Murchison Highway crossing during
1994 and 1995 identified the Argent to be largely rated as healthy, although riffle
sampling in 1995 identified this habitat to be slightly impaired ‘B’ (0.66). This appears to
have recovered in 1996.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 71
Surveys of locations downstream of the Renison Bell Mine in 1997 indicate that the river
health rating for the Argent River downstream of the township ranged from Healthy to
Severely Impaired and varied depending on habitat sampled. Edgewater habitat ranged
from Pristine ‘A’ (0.95) in spring to slightly impaired ‘B’ (0.52) in autumn, whereas the riffle
habitat ranked as slightly impaired in spring to extremely impaired in autumn. Not only is
this site downstream of Renison, it is also immediately downstream of the Argent Dam.
Inputs from these two sources are likely to impact this site.
The riffle habitat downstream of Renison was Extremely Impaired during the spring and
autumn sampling events with respective river health ratings of ‘D’ (0.13) and ‘D’ (0.15).
The edge water habitats were slightly healthier. These samples ranked as slightly
impaired ‘B’ (0.5) to impaired ‘C’ (0.42) for autumn and spring.
Recent Data
BMT JV engaged Todd Walsh to conduct invertebrate ecology monitoring to undertake an
AUSRIVAS assessments twice a year since 2011 at two sites along the Ring River and
three sites along the Argent River (see Figure 3-3, p.53). The survey reports provided by
BMT JV are included in Appendix N.
Mirroring the DPIPWE data for the upper Argent, the “reference” site (ARGENT 001)
shows a high degree of naturalness with A and B. The remaining sample points are
noticeably poor indicating long term damage from historical mining.
Table 3-11 AUSRIVAS results from invertebrate surveys 2011-2014
Code Name
Aut
um
n 20
11
Spr
ing
201
1
Aut
um
n 20
12
Spr
ing
201
2
Aut
um
n 20
13
Spr
ing
201
3
Aut
um
n 20
14
ARGENT001
Argent River, Murchison Highway
1.02 0.94 1.18 0.94 1.02 0.80 1.02
A A X A A B A
ARGENT002
Argent River below Renison Bell
0.47 0.35 0.16 0.21 0.00 0.14 0.16
C C D D D D D
ARGENT003
Argent River below Hydro station
N/A 0.13 0.23 0.13 0.08 0.13 0.16
N/A D D D D D D
RING001 Ring River above Renison Bell
0.08 0.26 0.23 0.26 0.31 0.39 0.16
D D D D C C C
RING002 Ring River below Renison Bell
0.14 0.28 0.14 0.34 0.14 0.20 0.00
D C D C D D D
Conclusion
Overall, the AUSRIVAS data supplied by the DPIPWE and Todd Walsh indicate that the
upper reaches of the Argent and Ring Rivers are relatively healthy, however the
ecological health of these systems diminish down gradient.
The extensive mining history within these catchments is likely to have contributed to the
poor ecological health observed at the sampling locations. It is evident from the data that
inputs from Bakers Creek (upstream of Renison) have had a detrimental impact on the
72 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Ring River. Corresponding water quality data sampled as part of the AUSRIVAS DPIPWE
survey shows a marked increase in electrical conductivity (135 µS/cm – 517 µS/cm) and
a decrease in pH (7.01 – 3.96) immediately upstream and downstream of the Bakers
Creek confluence.
Both sites on the Argent River, downstream of the Argent Dam are also likely to be
influenced by a number of confounding variables such as the Argent Dam itself, the
current Renison TSFs and runoff and seepage from the mine.
CFEV
The DPIPWE Conservation of Freshwater Ecosystem Values (CFEV) Database provides
an assessment of the conservation management priorities (CMP) of Tasmanian
freshwater ecosystems.
The CFEV assessment framework uses: biophysical classification and condition
(‘Naturalness’) to determine the Conservation Value and Conservation Management
Priority of watercourses in terms of ecosystem health (DPIW 2005).
The CFEV scores for the streams close to the project footprint (see Figure 3-3) are presented in Table 3-12.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 73
Table 3-12 CFEV Aquatic Ecology Indices for watercourses in the project area
Stream Biophysical Classes Naturalness Conservation Value
Conservation Management Priority
Unnamed creek downstream of D Dam
Perennial, high volume, low variability stream with ‘Western dissected surface’ river type. Western lowland rainforest tree class. Common macroinvertebrate assemblage with presence of A.Tricopsis. Low fish or macrophyte presence
Medium Significantly altered from natural condition, a majority of the stream indicates severe impairment.
Low with Platypus (Orthorynchus anatinus) identified as sole Special Value).
Low to Moderate due to low land security tenure and surrounding land uses
Unnamed C Dam Pieman Tributary
High – Medium Majority in near natural condition, some significantly altered.
Argent River
Perennial, high volume, low variability stream with ‘Western dissected surface’ river type. Western lowland rainforest tree class. Depauperate macrophyte assemblages Native fish species present.
Near-natural condition from geomorphological, fluvial and riparian vegetation condition. Biological condition and macroinvertebrates significantly impaired.
Moderate Mainly low but some slightly higher land tenure security.
Ring River
Ring River downstream of the proposed D Dam discharge point is essentially part of Lake Pieman. CFEV data for Lake Pieman covers a large area and unlikely to reflect the specific condition of the highly impacted Ring River arm.
3.7 Natural Hazards and Processes
The D Dam footprint may be vulnerable to natural fires as it is surrounded by native
vegetation. In the area surrounding Renison bushfires occur on average once every ten
years. Fire risk is covered in more detail in Section 4.15.
The high rainfall (see Section 3.4.2) in the area indicates that there is a risk of flooding. D
Dam has been designed as a High-C hazard category. The design flood event is
therefore 1:10,000 Annual Exceedance Probability (AEP).
There have been no known landslips in the D Dam footprint during recent history.
3.8 Socio-economic Aspects
The West Coast of Tasmania is sparsely populated with population centres limited to
mainly small settlements that have developed around primary industries. The three main
settlements within 20 km of Renison are Rosebery (population 922), Zeehan (population
728) and Tullah (population 192), based on the 2011 census.
74 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
The workforce of Renison Bell Tin Mine is mainly based in Zeehan. Zeehan was
established as a mining town in 1882. Zeehan is a part of the West Coast Council local
government area (LGA), which is dominated by mining towns (the LGA includes
Rosebery, Zeehan, Queenstown, Strahan and Tullah).
In the 2011 Census4 20.9% of the population usually resident in Zeehan (Urban Centre
Localities) were children aged between 0-14 years, and 21.5 % were persons aged 55
years and over. The median age of persons in Rosebery (Urban Centre Localities) was
36 years, compared with 37 years for persons in Australia.
In the 2011 Census, in Zeehan, 22.7% of employed people over the age of 15 worked in
Metal Ore Mining. Others were employment in Accommodation (10.9%), Exploration
(4.5%), Building Cleaning, Pest Control and Gardening Services (4.5%) and Specialised
Machinery and Equipment Manufacturing (4.2%).
4ABS website
(http://www.censusdata.abs.gov.au/census_services/getproduct/census/2011/quickstat/SSC60420?opendocument&navpos=220)
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 75
4. Potential Effects and Their Management 4.1 Surface Water
4.1.1 Legislative, Policy and Performance Requirements
The key policy document describing the management of liquid waste in Tasmania is the
State Policy on Water Quality Management 1997 (SPWQM). The purpose of this policy is
to protect or enhance Tasmania’s water resources while allowing for sustainable
development.
Targeted WQOs and identified PEVs (see Section 3.4.4) are used to control pollutants.
Pollutants discharged into waterways should be reduced as far as is reasonable and
practicable, by the use of best practice environmental management and the waste
management hierarchy.
The SPWQM stipulates that if it is not reasonable or practical to reduce the levels of
pollutants in the wastewater to a level which would be required to achieve the WQOs for
the receiving waters at the point of discharge, the Board (EPA) may designate a mixing
zone around the point of discharge. Where a mixing zone has been designated, emission
limits must be set at levels which will not prejudice the achievement of WQOs at or
beyond the edge of the mixing zone.
4.1.2 Existing Conditions
Existing surface water conditions are described in 3.4.4.
4.1.3 Construction Impacts and Mitigation
Receptors
For the purposes of this assessment the receptors of D Dam impacts are Lake Pieman
including the Ring River Arm and small unnamed and ephemeral creeks downstream of
the Construction sites. More broadly receptors are defined by the PEVs outlined in
Section 3.4.4.
Effects
D Dam construction may result in the following potential impacts to receiving waters:
Contamination from hazardous material spills.
Construction will use hazardous liquids such as fuels and oils within the TSF
footprint, borrow areas and haul road. Risk of significant spills from vehicle use is
very low. Some refuelling may take place on site which is managed according to
the measures set out below and presents a very low risk of impact. However if
allowed to take place, a spill could reduce water quality and cause harm to aquatic
wildlife if allowed to enter local surface or groundwater.
Increase in suspended sediments from erosion and sedimentation
Heavy rain falling on exposed soil, rock and stockpiled loose material may cause
increased suspended sediment in local ephemeral creeks and potentially the Ring
River and Lake Pieman. The locations where suspended sediment is most likely to
be generated are:
The TSF storage area
76 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Haul road
C Dam Borrow Area
West Pieman Borrow Area
Excavation of fresh rock from borrow areas could expose PAF material.
This could result in minor generation of AMD within the quarry (although of far
lesser nature than the AMD issues associated with mine generated waste rock or
tailings). If PAF material was extracted and used for embankment construction, it
could be acid forming rock during construction excavations in the TSF storage or
borrow areas. These could result in minor water quality effect
Releases of cement during grouting.
Accidental releases of cement during preparation or handling on the surface, or
seepages of grout along preferential pathways to the surface during pumping,
could lead to plumes of suspended cement material and increased pH in local
watercourses and potential harm to aquatic ecology.
Releases of wastewater.
The refining of sand for the ‘Zone 2’ filter material in the embankment will generate
waste water similar to the suspended sediment generated by erosion and runoff.
Discharges from the washing plant will be directed to a sediment pond within the
TSF storage area. Small amounts of domestic wastewater will be generated which
will be removed by a licensed contractor to an appropriate waste water treatment
plant. No surface water impacts are expected.
Mitigation
Hazardous Materials Control
Hazardous materials will be transported, stored and handled according to relevant
standards and legal requirements. Specific measures to prevent and mitigate impacts to
surface water from releases of hazardous materials are as follows:
Hazardous liquids will be stored securely in existing storage at the Renison
Process Plant in bunded, impermeable areas with a minimum bund volume of
110% of the volume of the largest single stored volume within the bund;
Refuelling will take place at the permanent vehicle refuelling facility at the Renison
Processing Plant where practicable. If on site refuelling is required, fuelling will use
a mobile bowser with drip tray, spill kit and operated by trained personnel;
A register of hazardous materials with safety, storage, segregation and handling
information including Material Safety Data Sheets (MSDS) will be held on site;
Handling of hazardous liquids will be on an impermeable surface with isolated
drainage, channelled into an oil interceptor where applicable;
Spill kits will be supplied and maintained where chemicals are stored or used; and
Hazardous materials will be stored an adequate distance away from watercourses
storm water drains.
Response to a spill will be managed through an Environmental Incident Control Plan, the
framework for which is described in 6.2.11.
Sediment Pollution
The following measures will be employed to manage erosion:
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 77
Temporary construction drainage around the TSF Footprint will be fed into the
cleared base of the TSF to allow settlement of sediment prior to discharge.
Diversion drains will be constructed where uncontaminated run-off can flow
downslope towards the D Dam footprint, borrow area boundaries, earthworks or
stockpiles, which will feed to the nearest natural drainage lines.
The drained temporary access road within the D Dam footprint will be angled
towards the D Dam storage area as a barrier to runoff from outside. Elsewhere, cut
off drains will be installed upslope of cleared areas.
Vegetation will be cleared downslope from the centre of the D Dam footprint and,
progressively, from each of the borrow areas as barriers to sediment runoff,
avoiding the need for sediment fences.
Although dependent on a number of factors (see Section 2.10.2) the construction
programme will target drier months (November to March) for embankment
construction, to minimise exposure of earthworks during periods of heavy rain.
Runoff within the TSF storage area will drain towards the footprints of the four
embankments of the Stage 1 TSF. Prior to the start of embankment construction
berms of soil and rock will form settling ponds at each embankment. These will be
designed to retain runoff to allow settlement of sand and silt prior to discharge.
Earthworks, soil stockpiles (as discussed in Section 2.10.7) and exposed surfaces
will be revegetated with stockpiled topsoil as soon as possible.
Access to the D Dam site from the Renison Process Plant will be via existing site
access roads with existing sediment and erosion controls.
Haul road to the borrow areas (see Figure 2-1) will incorporate the following
measures to prevent sediment and erosion:
– Where possible stormwater runoff will be diverted from access roads using
drains
– Adequate drainage controls (e.g. cross drainage systems and/or longitudinal
drainage)
– Sediment control pond; and
– Design grade (slope) of roads will be minimised.
Borrow area drainage will be managed as follows:
– All benches will be self-draining along the bench to a suitable discharge point or
settling pond.
– Each borrow area will have a settlement pond to capture silty runoff prior to
discharge to water course.
– Borrow areas will be revegetated after use, as described in Section 8.
The detailed implementation of these measures will be described in an Erosion and
Sediment Control Plan.
Visual monitoring of runoff from the main discharge points of active construction areas will
form part of the construction surveillance programme set out in Section 7.2.
Control of PAF Construction Materials
The following measures will be taken to manage potential AMD issues associated with
construction materials:
78 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
If deemed necessary following geological assessment, geochemical samples will
be taken during the detailed geotechnical surveys of borrow areas and tested for
NAPP and NAG. Any zones identified as being PAF will be avoided.
Once fresh rock (including that to be crushed for sand) is exposed in a borrow
area, it will be tested for NAPP and NAG at a minimum frequency of 1 round of
testing per 10,000 m3 of rockfill according to the “ARD Test Handbook, Project
387A” (AMIRA International Ltd, 2002).
Zone 3 materials placed onto the embankment will be Non-Acid Forming (NAF).
Any geochemically unsuitable rockfill will left in situ, or disposed of in the PAF cell.
Grouting
Cement will be carefully handled and pumping rates monitored during grouting to prevent
loss of control. Persistent, greater than expected grout consumption will be reported to
the site environmental manager and investigated. If a surface escape of grout is
discovered grouting pumping to the hole in question will cease.
4.1.4 Operational Impacts and Mitigation
Receptors
These are the same as for construction impacts above
Effects
The creation of the TSF will alter local drainage and operational discharges will result in
changes to the quality of receiving waters.
Appendix M describes the model that has been used to estimate the impact of discharges
from D Dam on local receiving waters.
Impact on Quality of Receiving Waters
Modelling Scenarios
The assessment used the PHREEQC geochemical model together with mixing ratios
derived from the flows and volumes of the different components of the local receiving
environment. Two scenarios were assessed:
A modelled existing scenario. This was used to compare against measured data for
the same area and indicated that the model is generally conservative. It was also
used as a baseline against which to compare the predicted effects of the
discharge; and
The proposed scenario (D Dam decant and seepage discharges into the Ring
River and Lake Pieman respectively).
Dilution (or mixing ratios) between reservoir waters and tailings discharge were estimated
for high flow (winter /spring), typical summer low flow and plausible worst case low flows.
Water Quality Data
Ambient environmental water quality was taken from data obtained between July 2007
and June 2011.
The predicted water quality of the new discharge for D-Dam at site TD was obtained from
geochemical testing of tailings liquor samples taken between November 2013 and
February 2014 (see 2.7.2).
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 79
Flow Data
Flows were estimated from monthly averaged summer (February) and late winter/early
spring (October) data from gauges on the Ring River, Argent River, Huskinsson River and
Pieman Dam. In the absence of sufficient data to calculate a 7Q10 low flow, a suitable
low flow estimate was made (see Appendix M).
Estimates of discharge from D Dam are derived from the water balance (see Appendix F).
These are as follows:
D Dam decant discharge point (TD) - constant discharge of 0.077 m3/s.
D Dam main embankment seepage (S2) - discharge of 0.002 m3/s;
Residual A and B Dam overflow (TB) - constant discharge of 0.020 m3/s;
Seepage from the eastern ‘decant’ section of the D Dam embankment will collect and
discharge with TD. Given the topography and structure of D Dam, this is expected to be a
very small flow and unlikely to affect the volume or quality of discharge TD.
Assessment of Impacts
The key conclusions of the assessment are as follows:
The poor water quality of the Ring River reservoir arm (mainly due to the high
background water quality in water flowing down the Ring River from RAD) is the
main reason for most trace metals not meeting the site specific trigger values.
Very minor increases in levels of Cd, Zn, Mg and K are predicted due to TD
discharging to the Ring River Arm.
Due to the existing high levels of contaminants within the Ring River itself, it is not
meaningful to assess a ‘mixing zone’ for contaminants from discharge TD.
In the main body of the reservoir, high dilution maintains metals below the site
specific trigger values (or nearly so). Although it is not possible to model mixing
zones for this environment, based on the changes to concentration resulting from D
Dam, is not anticipated that a mixing extending across the entire Ring River Arm
under normal conditions leading to a barrier to species migration.
In certain summer conditions, Cu and Zn however may exhibit elevated levels
marginally above the trigger values. However given that the concentration of these
in the Ring River upstream of Renison operations, it is reasonable to say that this
‘mixing zone’ primarily results from inputs of contaminants originating from other
sources and appears not to be influenced by the discharge from TD.
Overall the proposed discharge from TD has a limited impact on the receiving
environment as a whole system due to the existing impacts from the Ring River as
well as the high level of dilution achieved in the Pieman.
The TD discharge is not anticipated to impact on the Argent River, which is likely to
continually improve following the closure of C Dam and resumption of A and B
Dam.
Overall the proposed discharge from TD has a limited impact on the receiving
environment as a whole system due to the existing impacts from the Ring and
Argent Rivers as well as the high level of dilution achieved in the Pieman.
While the modelled impact is relatively low, due in part to existing impacts, there remains
a requirement to minimise potential pollution (namely AMD) from the site which is
addressed through the proposed dam design and operation (see ‘Mitigation’ below).
80 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Altered Hydrology
Construction of the TSF and excavation of the borrow areas will result in permanent
alterations to natural drainage:
The majority of the catchment of the unnamed creek that currently drains the D
Dam footprint will be covered by the TSF. Downstream of the TSF, the remaining
200 m of the creek will experience reduced flows due to truncation of its catchment
and diversion of the normal drainage upstream of the TSF embankment through
the decant tower. Overflow during peak runoff during Phase 1 will drain into the
unnamed creek. Once the embankment reaches its final level the spillway will be
directed eastwards into the Ring River
The proposed borrow areas are sited on rises and will not require diversion of any
existing watercourses
Lake Pieman will not experience any measureable change in water flows as a
result of changes to local hydrology.
Aquatic Ecology
The implications for aquatic ecology in the area relate to the predicted changes in water
quality.
Aquatic ecology habitat in the creek draining the D Dam footprint will mainly be removed,
and the remaining 200 m may experience changes in flows, potentially affecting aquatic
ecology within. Much of this system has been affected by previous mining activity,
lessening its ecological value.
However the water quality in this creek will improve dramatically with the removal of the
existing S2 seepage. Partial removal of S1 seepage from the creek drainage from the D1
embankment should also improve water quality.
Downstream of TD, the Ring River is predicted to experience a marginal decline in water
quality for some parameters and improve for others as a result of the D Dam discharge.
Overall in terms of ecological health this is unlikely to represent a worsening of the
existing situation which is currently impaired with river health ratings of C and D.
According to the modelling, the water quality within Lake Pieman is not predicted to
change significantly relative to the existing situation and hence not be detrimental to the
ecosystem health.
Monitoring aquatic ecology is outlined in Section 4.1.5.
Mitigation
Although the receiving environment is heavily impacted, to the point where the proposal
would have no noticeable impact on water quality, Sections 16 and 17 of the State Policy
on Water Quality Management 1997 nonetheless requires reasonable effort to limit AMD
emissions from the site.
In order to do this the management of the acidification through the tailings deposition
plan, control of the decant pond level and pH control by dosing with lime will be used to
prevent AMD formation and control decant quality. These are discussed in Section 2.7.
The tailings will be neutralised with hydrated lime slurry at the processing plant to a
nominal pH 8.5. This neutralises any free acid and precipitates metals, sulphate and
fluoride.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 81
Lime dosage will respond to continuous monitoring of pH level in the pond which will
control any fluctuations resulting from temporary seepage influxes from A Dam, and
intercepted seepage from B and C Dam.
Where any significant negative trends or breaches of EPN compliance in decant or
seepage water quality are identified by routine monitoring:
Suitable short term treatments (such as additional lime dosing) will be applied as
soon as possible;
An investigation will be conducted to determine the reason for the trend;
An assessment of the long term risk of the trend to the environment will be
undertaken;
Based on the risk assessment suitable longer term management measures will be
designed and put in place; and
Any breaches of EPN compliance will be reported immediately to the EPA and
negative trends will be highlighted in the Annual Environmental Report.
As discussed in Section 2.7.3 sumps and pumping system will also be included
immediately downstream of the v-notch weirs in order to pump B and C Dam seepages
into the D Dam decant pond to enable ongoing treatment.
Weed control in or near watercourses or areas of wetland will be undertaken by manual
removal where practicable. If this is not possible targeted spot spraying of low-toxicity
non-residual herbicides may be required.
As D Dam is being constructed as a ‘wet wall’, in the event of closure the decant tower
and channel would be decommissioned and surface water overflow runoff would be
channelled via a spillway as described in 8.
4.1.5 Monitoring
Construction
Routine construction surveillance (See Section 7.2) will monitor for accidental releases to
surface water and implement corrective action accordingly. This will include:
Daily visual inspection for leaks and spills of hazardous materials at storage and
fuelling areas and where plant are operating;
Continuous monitoring of grouting rates at pumps during grouting;
Daily visual monitoring of site runoff for turbidity at points draining active
earthworks and exposed soils;
Operation
Tailings Geochemistry
The present daily monitoring of tailings streams (BMT JV, 20135) (see Section 2.7.1) will
continue at the Renison Plant to characterise tailings geochemistry before tailings are
sent to D Dam.
Decant pond level will be monitored using an automated gauged system with alarms at
the processing plant.
A piezometer will provide continuous monitoring of pH level within the Decant Pond.
5 The Current BMT JV Environmental Management Plan 2013 is available from BMT JV on request.
82 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Water Quality and Flow Monitoring
There will be a new monitoring regime for water quality and flows, incorporating existing
monitoring points as defined in the Renison Environmental Management Plan (BMT JV,
2013).
The monitoring points (locations shown on Figure 3-3) will be as:
TD (new discharge from D Dam);
S4 (seepage from the D1 embankment)
S3 (seepage from D4 ‘Decant’ embankment);
S2 (seepage from D2 ‘Main’ embankment. Existing point S2 is the A / B Dam
seepage monitoring point. It will be moved to a point downstream of the D Dam
embankment on the unnamed creek draining northwest into Lake Pieman;
B and C Dam seepage interceptors; and
A-dam embankment seepage within D Dam footprint (construction and until the fill
level reaches the toe of the A Dam embankment).
The parameters and frequency of sampling are summarised in Table 4-1
Table 4-1 Monitoring
Parameter Method S2, S3, S4, C and B Dam seepage interceptors, A Dam
TD
Flow V-notch weir Fortnightly Fortnightly
pH In-situ meter Fortnightly Fortnightly
Conductivity (µscm-1) In-situ meter Fortnightly Fortnightly
Total Suspended Solids (mg/l)
Sample and lab analysis Fortnightly Fortnightly
Temperature ( C) In-situ meter Fortnightly Fortnightly
Fluoride (mg/l) Sample and lab analysis Fortnightly Fortnightly
Sulphate (mg/l Sample and lab analysis Fortnightly Fortnightly
Iron (mg/l) Sample and lab analysis Fortnightly Fortnightly
Manganese (mg/l) Sample and lab analysis Fortnightly Fortnightly
Total Phosphorus (mg/l) Sample and lab analysis - Monthly
Total Petroleum Hydrocarbons (mg/l)
Sample and lab analysis - Monthly
Total Cu, Pb, Zn, Cd, Cr, Hg, Co, Ni, Al, As (mg/l)
Sample and lab analysis Monthly Monthly
Regular visual assessments of D Dam embankment will be undertaken to identify any
possible additional seepage.
Ambient Water Quality
The present regime for monitoring of fixed discharge points (as defined in the Renison
Environmental Management Plan (BMT JV, 2013) will incorporate the following new
discharge monitoring points (shown on Figure 3-3):
RAB (Ring River above existing point TB to monitor ambient water quality prior to
any inputs from the TSF system); and
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 83
RBB (Ring River below existing point TB to monitor ambient water quality following
TB and before TD).
Details of monitoring at RAB and RBB are summarised in Table 4-2.
Table 4-2 Additional Monitoring Points
Parameter Method RAB RBB
pH In-situ meter Monthly Monthly
Conductivity (µscm-1) In-situ meter Monthly Monthly
Total Suspended Solids (mg/l)
Sample and lab analysis Monthly Monthly
Temperature ( C) In-situ meter Monthly Monthly
Depth (m) Plumb line Monthly Monthly
Dissolved Oxygen (mg/l) In-situ meter Monthly Monthly
Fluoride (mg/l) Sample and lab analysis Monthly Monthly
Sulphate (mg/l Sample and lab analysis Monthly Monthly
Total Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Zn (mg/l)
Sample and lab analysis Monthly Monthly
Aquatic Ecology Monitoring
The existing 6 monthly aquatic ecology monitoring (described in Section 3.6) will
continue, using the same methodology. It will include a new monitoring location where the
discharge enters the Ring River and one monitoring event will occur in advance of
commissioning of D Dam.
4.1.6 Management Commitments
Construction
Commitments proposed during construction are as follows:
Commitment 1 Measures to prevent and mitigate impacts on surface water from releases of hazardous materials will include secure storage, careful handling, and recording of hazardous materials as described in Section 4.1.3.
Commitment 2 An Environmental Incident Control Plan will be prepared by the contractor based on the framework in Section 6.2.11.
Commitment 3 Measures to manage erosion and sediment described in Section 4.1.3 will be implemented though an Erosion and Sediment Control Plan during construction.
Commitment 4 Measure to potential AMD issues associated with construction materials will be taken as described in Section 4.1.3
Commitment 5 Cement will be carefully handled and pumping rates monitored during grouting to prevent loss of control.
Commitment 6 Weed control in sensitive areas will be undertaken by manual removal or targeted spot spraying with low-toxicity non-residual herbicides.
84 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Operation
Commitments associated with how surface water quality and flow will be managed during
the operation of D Dam are described as part of the proposal, in Section 2.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 85
4.2 Groundwater
4.2.1 Legislative, Policy and Performance Requirements
Groundwater management in Tasmania is governed by the SPWQM (1997) in which
groundwater quality targets are based on the PEVs (beneficial uses) maintenance of
ecosystems and primary recreational contact (see Section 3.4.5).
4.2.2 Existing Conditions
A summary of the existing environment is provided in Section 3.4.5 and in Appendix G.
4.2.3 Construction Impacts and Mitigation
Receptors
The receptors of groundwater impacts are ecosystems and recreational human users of
the following water bodies:
The Pleistocene sediments and Cambrian bedrock aquifers under and downstream
of the Project footprint); and,
Surface watercourses including Lake Pieman (including the Ring River arm) and a
number of small and ephemeral watercourses downstream of the TSF.
Effects
Although changes to groundwater flows and quality will take effect from early in the
Project, potential impacts from the presence of the TSF and its contents are discussed
under Operational Impacts in Section 4.2.4 below.
Besides these, potential construction impacts on groundwater from D Dam could include
the following:
Contamination of groundwater due to spills of hazardous liquids from construction
activities, see Section 4.1 (Surface water);
Contamination of groundwater from grouting; and
Changes to groundwater flows from excavation due to borrows.
Creation of the grout curtain will require the injection of large volumes of cement grout
into the foundation rock below the embankment. The high alkalinity of cement may pose a
risk to groundwater quality if injected in an uncontrolled manner to vulnerable
groundwater systems. However, the risk of such an impact is very low given the low
sensitivity and the prevalent acidity of the local groundwater.
Borrow excavation may locally alter the flow of groundwater. However the borrow areas
(see Section 2.10.7) will be relatively shallow and sited on rises which will limit the
potential for groundwater impacts from dewatering.
Mitigation
Measures to prevent and mitigate impacts to groundwater from spills of hazardous liquids
is described in Section 4.1.3.
86 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.2.4 Operational Impacts and Mitigation
Conceptual Groundwater Model
As for construction impacts, receptors are defined by the Beneficial Uses. The pathways
by which these may be affected are shown in the conceptual groundwater model (see
Figure 4-1), which comprises the following basic elements:
The Pleistocene sediments (variable permeability with discontinuous zones of high
permeability sands and gravels);
The Cambrian bedrock (lower permeability, decreasing with depth);
The existing TSFs;
Lake Pieman and other surface water discharging into it; and
D Dam.
Both sediments and bedrock aquifers range from confined to unconfined, depending on
the clay content of surface materials, but recharge by infiltrating rainfall is likely to be
significant given the high rainfall.
Figure 4-1 Conceptual Hydrogeological Model (from Appendix G)
Effects
Inflow
As discussed in Section 2.2.9 estimated average inflow is:
Tailings effluent (57.35 l/s);
Rainwater (30.9 l/s); and
Seepage from the existing TSFs (1.7 l/s).
Following construction of the proposed D Dam embankment, clay blanket and grout
curtain cut-off, the northward flow from existing TSFs to Lake Pieman should be reduced
or intercepted in the embankment soil drains.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 87
Flow within tailings
As discussed in Section 2.2.6, tailings tend to have low hydraulic conductivity at around
1x10-3m/d for deep tailings and 1x10-2m/d for shallow tailings. This is higher than that of
the embankment so seepage from the existing and proposed TSFs is likely to be
dominated by downward seepage through the tailings then lateral flow through the
underlying bedrock and sediments. However this will be retarded by the grout curtains
(which extent below the tailings level), clay liners and PAF cell.
Discharge
Seepage analysis has been completed as part of the “Bluestone Mines Tasmania JV Pty
Ltd: D Dam Stage 1 – RL2168 m, Preconstruction Report” dated December 2014 (GHD,
2014) in order to determine the likely seepage rates from the proposed dam. The analysis
has been based on the ultimate embankment crest height of 180 m AHD in order to
provide long term seepage estimates.
The Rocscience Slide 6.0 software package was used to perform the 2D Finite Element
Method (Groundwater mode) seepage analysis at the following locations:
D2 (Main) Embankment, representing CH350 – CH700
Ridgeline Embankment, representing CH0 – CH350 and CH700 – CH1250
D4 (Decant) Embankment, representing CH1250 – CH1560
Separate flux sections were set up to estimate the seepage through the embankment and
into the foundations as shown below in Figure 4-2.
Figure 4-2 Example Seepage Section: D2 (Main) Embankment
Table 4-3 Estimated Seepage from Proposed Design
Section L/s ML/year
Embankment 1.7 54
Foundation 4.0 126
Total 5.7 180
Note that the 2 d seepage model is conservative
Impacts
Predicted impacts on groundwater level from D Dam are:
Increased groundwater recharge and mounding of the water table, and leading to
waterlogging of low-lying areas. This is evident in surface discharges of
groundwater to the north of A, B and C Dams and to the southeast of B Dam;
A resultant increase in hydraulic gradients and base flow to surface water systems;
and
88 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Embankment cut-off walls and foundation drains can reduce groundwater flow to
downstream wetlands.
Potential impacts on groundwater quality from D Dam are:
Pushing out existing poor quality water (short term). The increase in head below D
Dam due to the increased recharge by seepage water could displace contaminated
groundwater derived from A, B and C dams. The groundwater chemistry however
indicates that groundwater quality is generally within the discharge limits set out in
EPN 7092/2.
PAF cell is unlikely to significantly alter the overall seepage chemistry. This is
unlikely to significantly alter the overall seepage chemistry as it will be placed on a
clay liner and represents a relatively small component of the flow path and hence
only a relatively small proportion of the seepage will pass through the cell. As an
added safeguard during placement, the waste rock stockpiles will be treated with
hydrated lime prior to the placement of waste rock inside the PAF cell.
Contamination of groundwater from D Dam seepage. The loading of Fe, Mn, SO4
and F is from D Dam seepage and is presented below in Table 4-4. The seepage
rate is based on simple vertical drainage through the low permeability deposited
tailings, with flow (500 ML/y) equal to the product of the D-Dam area, the hydraulic
gradient and the median tailings permeability of the tailings. The seepage rate was
then revised downwards to 180 ML/y using 2-D finite–element seepage modelling,
as detailed in the D Dam Stage 1 - RL2168m Preconstruction Report (GHD 2014)
as part of the dam design process.
Reduction of seepage discharge from existing seepage from A, B and C Dams.
Seepage from the northern sides of A, B and C dams will initially be captured by D
Dam, and blocked or intercepted by the long-term by the D Dam embankment
system.
Table 4-4 Estimated Annual Contaminant Loadings
Source Fe Mn SO4 F
Concentration (mg/L) 0.075 31 1 800 14
Loading (kg/y) based on 44.2 ML/month (500 ML/year)
40 16 430 954 000 7 420
Loading based on 15 ML/month (180 ML/y) 14 5 576 323 756 2 518
Mitigation
Management measures will limit impacts to groundwater arising from proposed site
operations. These are:
Tailings discharge to D Dam will be managed through placement and sulphide
segregation to prevent oxidisation of sulphidic tailings as described in 2.5.2. The
management of HST with rapid burial and separate LST beach will result in a
significant decrease in metal and sulphate content and maintain neutral conditions
in decant and leachate.
Prior to commissioning of the D Dam, a detailed Tailings Management Plan (TMP)
will be developed by BMTJV to document all elements associated with the
deposition and storage of tailings within the dam.
Installation of a grout curtain below the main and decant embankments, upstream
clay linings and the tailings themselves (as described in Section 2.2.6) will
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 89
significantly reduce seepage from D Dam, as well as northward seepage from the
existing C, A and B Dams;
Clay linings will be installed locally where, following stripping of soil, zones of
gravelly and cobbly fluvio-glacial sediment are uncovered.
Seepage beyond the grout curtain in the embankment and from the areas where
the D dam embankment abuts the existing embankments will be captured by a filter
blanket and embankment drainage system. If the collected seepage exceeds
discharge requirement, such as in the case of migration of existing groundwater
contamination at higher than currently identified concentrations, the seepage will
be collected and returned to the TSF for treatment, primarily neutralisation if
required, or treated and blended with the decant discharge, depending on the
overall water quality.
Surface water runoff will be diverted around D dam and discharged downstream.
This will provide additional flows to any sensitive wetlands below the embankment.
The PAF Cell will be encapsulated within a 1 m thick liner of impermeable clay with
an underlying liner and outer layer of NAF rip rap.
All of PAF waste material will be placed below 160 m AHD which will allow it to be
inundated and saturated within two years.
PAF waste rock will be dosed with sufficient lime calculated based on the TAA data
to neutralise existing and potential acidity until full inundation by tailings and water
occurs. The dosing will occur at the current stockpiles as the material is excavated
for transport to D Dam.
A failure of the groundwater protection measures described above would most likely be
detected through changes in seepage quality identified through routine monitoring (see
Section 4.1.5). If any significant negative trends or breaches of EPN compliance in
borehole water quality are identified by routine monitoring:
An investigation will be conducted to determine the reason for the trend;
An assessment of the long term risk of the trend to the environment will be
undertaken;
Based on the risk assessment suitable longer term management measures will be
designed and put in place; and
Any breaches of EPN compliance will be reported immediately to the EPA and
negative trends will be highlighted in the Annual Environmental Report.
4.2.5 Monitoring
Construction
Routine construction surveillance (See Section 7.2) will monitor for accidental releases to
groundwater.
Operation
Monitoring of water quality will continue groundwater monitoring in existing bores (see
Table 4-5 and Figure 3-3, Page 53).
90 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Table 4-5 Groundwater Monitoring Boreholes
Borehole E N Purpose
GW5 370028 5372715 Baseline upstream of A, B and C Dam
GW6 369207 5373444 Downstream of C Dam (C Dam Borrow Area)
GW9 370661 5373789 Downstream of D Dam (towards Ring River Arm)
GW10 370195 5374138 Downstream of D Dam (towards Lake Pieman)
GW11 370194 5374137 Downstream of D Dam (towards Lake Pieman)
GW12 371110 5372972 Downstream of B Dam
Groundwater Levels
Water level will be recorded by loggers at hourly intervals, data for which will be
downloaded quarterly.
Hydrographs showing the groundwater level data, along with rainfall and TSF water levels
data, will be created provide early warning of any anomalous water levels that may
indicate unexpected seepage from the TSFs.
Embankment pore pressure will be continuously monitored using four arrays of
piezometers as described in Section 2.2.6.
Seepage flows in the D Dam toe drains will be monitored weekly at v-notch weirs S 2, 3
and 4.
Embankment Pore Pressure
Vibrating wire piezometers will continuously monitor embankment pore pressure in D 1,
D2 and D4 embankment as described in Section 2.2.6.
Groundwater Chemistry
Groundwater quality monitoring of the bore network will be undertaken for two years after
which frequency and scope will be reviewed and modified as necessary.
Major Ions (sodium, calcium, potassium, magnesium, chloride, sulphate,
bicarbonate, carbonate fluoride;) measured quarterly;
Dissolved and total metals (Sb, As, Cd, Cr, Co, Cu, Pb, Mn, Hg, Ni, Se, Zn)
measured quarterly;
pH, EC and TDS measured quarterly.
Monitored values will be compared with the current site discharge licence requirements
under EPN 7092/2. Changes to the geochemistry indicating a possible oxidation, acid
generation or an increase in metalliferous leaching within the TSF will be investigated
immediately.
Seepage quality will be measured fortnightly (as discussed in Section 4.1).
4.2.6 Management Commitments
Management commitments relevant to groundwater protection
Construction
Measures to control groundwater quality during construction are as described in Section
4.1.3.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 91
Operation
Commitment 7 A Tailings Management Plan will be prepared prior to commissioning of D Dam.
Commitment 8 Tailings will be placed and HST segregated to prevent oxidisation as described in 2.5.2.
Commitment 9 Grout curtains below the main and decant embankments, a clay lining of the decant pond and any other permeable zones will be installed as described in Section 2.2.6.
Commitment 10 All PAF waste material will be placed below 160 m AHD to allow inundation and saturation within two years.
Commitment 11 PAF waste rock will be dosed with sufficient lime to neutralise existing and potential acidity until full inundation occurs.
92 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.3 Biodiversity and Natural Values
This section covers impacts on biodiversity and natural values. It focuses on the
terrestrial environment, with impacts on aquatic ecology covered in Sections 4.1.2 and
4.1.4.
4.3.1 Legislative, Policy and Performance Requirements
Biodiversity and nature conservation values in Tasmania are protected by a range of
legislation and policy. The key documents relevant to this project include:
Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act);
Tasmanian Threatened Species Protection Act 1995 (TSPA);
Forest Practices Act 1985 and associated regulations;
Weed Management Act 1999; and
Nature Conservation Act 2002.
In line with the requirements of the D Dam Project Specific Guidelines, a separate section
(Section 5) has been included to discuss impacts on Matters of National Environmental
Significance (MNES) protected under the EPBC Act. However the only MNES likely to be
affected by D Dam are threatened listed species, impacts on which are described fully in
this section and summarised in Section 5.
This assessment and associated mitigation requirements recognise the targets and criteria presented in Australia's Biodiversity Conservation Strategy 2010-2030 (2010), the
identification of threatened species and communities is consistent with the Threatened
Species Strategy for Tasmania (DPIPWE 2000).
Key performance requirements include:
Avoid and/or mitigate against potential impacts to native flora and fauna;
Avoid impacts to listed flora, fauna and vegetation communities. Where avoidance
is not possible minimise impacts as far as practicable; and
Minimise, control and eradicate any declared weed incursions arising from the
Project.
4.3.2 Existing Conditions
Existing conditions are described in Section 3.4.5 and in Appendix I. In summary the site
contains a range of native vegetation including one listed community, no listed flora have
been identified on site and there is habitat for a range of listed fauna species included on
both the State and Commonwealth legislation.
The distribution of native vegetation communities and the estimated distribution of fauna
habitat are shown in Figure 3-4 (page 67) and Figure 3-5 (page 68) respectively.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 93
4.3.3 Construction Impacts and Mitigation
Loss of Vegetation Communities from Site Clearance
Receptor
The 13 native vegetation communities identified within the Project footprint are listed in
Table 4-6, with the majority occurring inside the project footprint. One threatened
community will be impacted, although this is of relatively low quality.
Effect
Table 4-6 provides an estimate of the loss of native vegetation communities that will
result from clearance of D Dam and the borrow areas, in total c. 54.5 ha.
Table 4-6 Estimated Extent of Vegetation Clearance for Project
Vegetation Community Land Take (ha)
Total Extent in Region* (ha)
Remaining Extent within 15 km of footprint
(TASVEG 3.0)
Threatened Community (Y/N)
Freshwater aquatic sedgeland and rushland (ASF)
0.5 0# - Y
Acacia dealbata forest (NAD) 7.0 373.6 366.3 N
Acacia melanoxylon swamp forest (NAF)
0.6 134.3 133.7 N
Acacia melanoxylon forest on rises (NAR)
9.1 2,362.8 2353 N
Leptospermum scoparium-Acacia mucronata forest (NLA)
4.8 1,983.5 1978.3 N
Nothofagus-Phyllocladus short rainforest (RMS)
3.0 13,502 13,498.9 N
Nothofagus-Atherosperma rainforest (RMT)
14.2 13,486.2 13,471.6 N
Melaleuca squarrosa scrub (SMR)
1.2 47.1 45.8 N
Eucalyptus delegatensis forest over rainforest (WDR)
4.2 25.8 21.6 N
Eucalyptus nitida forest over rainforest (WNR)
4.9 683.5 678.3 N
Eucalyptus obliqua forest with broad-leaf shrubs (WOB)
2.6 34.8 32 N
Eucalyptus obliqua forest over Leptospermum (WOL)
0.1 0# - N
Eucalyptus obliqua forest over rainforest (WOR)
2.1 3,119 3,116.7 N
TOTAL 54.5 35,752.6 35,695.4 # Some communities identified within the Project footprint during the field survey(s) are not
included in current TASVEG mapping of the region. TASVEG mapping is largely based on
interpretation of aerial photographs, and is at a scale of 1:25,000. As such, field validation is
required to confirm the presence and extent of particular communities in any region, such as
occurred within the Project footprint.
The loss of the community Freshwater aquatic sedgeland and rushland (ASF), while
technically classified as a threatened community, is not considered a significant impact
due to the poor quality and immature nature of the wetlands identified on site, which
94 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
appear to have been created by soil and drainage disturbance during relatively recent
excavation.
The vegetation communities in the majority of the D Dam footprint and in the southern
half of the C Dam Borrow Area show impacts from historic logging, track clearance and
weed incursion.
The native vegetation communities in Table 4-6 are widely represented in the West of
Tasmania.
Approximately 18 ha of the 54.5 ha of cleared native vegetation will be rehabilitated
following closure of the borrow areas, as described in Section 8. Approximately two thirds
of the tailings surface will also be vegetated following closure.
Consequently the loss of vegetation communities is not considered a significant impact.
Mitigation
To minimise impacts to native vegetation, the following mitigation measures will be
implemented:
Vegetation clearance or damage outside the footprint will be avoided by flagging,
fencing and site access plans;
Detailed design phase will consider possible refinements to the footprint to reduce
the need for clearance, especially in high quality areas of native vegetation;
Where permitted by the construction programme and demand for materials, borrow
area excavation will first use existing cleared, disturbed areas and leave least
disturbed areas till last, so that any future reduction in material demand will
preserve the highest quality habitat within the footprint;
Storage of materials and/or machinery will utilise existing cleared areas;
A haul road from the borrow areas will be created by widening an existing track as
shown in ; and
A Post-Construction Rehabilitation Plan will be prepared and implemented with
rehabilitation of the borrow area footprints and haul road following construction
(see Section 8 of the DPEMP, GHD 2014).
Loss of Significant Flora from Site Clearance
Receptor
No threatened flora species have been identified within the project footprint.
Effects
The project is considered unlikely to impact on any threatened flora species.
Mitigation
As no threatened flora species are likely to occur within the project footprint, no additional
mitigation measures are proposed.
Fires and Weed Incursion into Vegetation Communities
Receptor
All of the native vegetation communities within the footprint (see Table 4-6) and its
immediate surroundings will be vulnerable to fire and weed incursion.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 95
Effects
Fires accidentally triggered by construction are discussed in Section 4.14. Although an
uncontrolled fire could have severe impacts on vegetation communities, high rainfall and
existing safety procedures make a large scale bush fire unlikely in the mining lease.
The construction of D Dam has potential to bring new weeds or pathogens on to site or
spread existing weeds to other parts of the site, however the existing wash down
procedure and site controls already in place go a long way to addressing this risk.
While no evidence of Phytophthora cinnamomi was seen at the site, there is potential to
import it from elsewhere. Since most of the construction vehicle movements will be within
the site (i.e. to and from the borrow areas) this risk is low.
Mitigation
Fire risk will be managed according to the existing BMT JV Emergency Management Plan
(MA007).
In addition to existing site procedures, during construction weed, disease and pest control
will be controlled by measures outlined in the Weed Management and Hygiene Plan (see
Appendix J) which, in summary, requires:
Training and induction of staff involved in the project;
Documentation of control actions;
Ongoing checks and surveillance for weeds during construction, with a particular
focus on canary broom, blackberry and gorse;
Implementation of weed control measures (hand removal, herbicide application,
stump cutting) described in Appendix J;
Auditing and corrective action to address any non-conformance;
Pre-, during and post-construction actions to address threats identified, particularly
weed management activities including weed control, washdown procedures and
monitoring. These actions will include but not be limited to:
– Any fill/material imported to site will be clean and free of weeds and/or
diseases; and
– Vehicles and machinery will be washed down using a mobile washing station
before entering the site.
Impacts on Threatened Fauna Species from Site Clearance
Receptors
The following terrestrial threatened fauna species were detected within or adjacent to the
project footprint during survey work in 2012 and 2013:
Tasmanian devil (TSPA: Endangered, EPBC: Endangered);
Tasmanian azure kingfisher (TSPA: Endangered, EPBC: Endangered);
Wedge-tailed eagle(TSPA: Endangered, EPBC: Endangered); and
Spotted-tailed quoll (TSPA:Rare, EPBC: Vulnerable) is considered likely to be
present on site based on the results of the scat analyses.
The project footprint also contains habitat suitable for the following threatened fauna
species, not confirmed during the field surveys:
96 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Tasmanian masked owl (TSPA: Endangered, EPBC: Vulnerable);
White-bellied sea-eagle (TSPA: Vulnerable, EPBC: Migratory);
Grey goshawk (TSPA: Endangered);
Latham’s snipe (EPBC: Migratory);
White-throated needletail (EPBC: Migratory);
Satin flycatcher (EPBC: Migratory).
Further detail for each of these species can be found in Table 3-7.
Effects
Tasmanian devil
The footprints of D-Dam and the borrow areas provide 54.5 ha of native foraging habitat
which will be lost during site clearanceBased on denning potential and vegetation type,
much less than 1 ha of this is high quality potential denning habitat (see Appendix I).
The 2013 survey found no evidence of active dens (including natal dens) within the
project footprint. The survey did however identify features which could be potential layups
and potential social den sites (and one ‘log and boulder’ complex with possibility of natal
denning).
The ‘log and boulder’ complex identified in the field survey is within the direct footprint of
D Dam and will therefore be removed as part of the works. This feature was created by
windrows from previous clearance and similar features will be created as a result of the
Project to compensate for loss of this feature.
However as these were neither active dens nor demonstrably products of Tasmanian
devils, clearance is not expected to require a permit under the Nature Conservation Act
2002 (which requires permits for direct impacts to threatened species and ‘products of
wildlife’).
However as the species is known from the area, in advance of site clearance there is
potential for the occupation of currently unoccupied potential layups and social den sites
or new dens, which would be destroyed during site clearance. Pre clearance surveys will
be undertake to address this risk.
The 54.5 ha of foraging habitat that will be cleared represents approximately 0.16% of the
extent of equivalent habitat in the locality (within a 15 km radius of the site). The 35,695.4
ha of native vegetation outside the project footprint (within a 15 km radius) is likely to be
sufficient to maintain the local and regional population of the species, which has an
average home range of c. 13 km2 across a 2-4 week period (Pemberton 1990).
None of the habitat within the project footprint is considered likely to be critical to the
survival of the species, and loss of this habitat is unlikely to result in the decline of the
Tasmanian devil on even a local scale.
The survey found no evidence of DFTD and assuming that it is absent from the site, this
could worsen the consequences of habitat loss, given that other areas regionally do have
the disease. However the low density of devils identified by the camera survey suggest
that the effect on local populations would still be low.
As discussed in Section 2.10.5 construction will generate minimal off-site traffic. However,
the embankment construction material will be moved from the borrow areas to the
embankment footprint by truck. With the introduction of vehicle movements comes the
potential for increased fauna mortalities from vehicle impacts. However, given the vehicle
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 97
daylight and speed restrictions (see 2.10.3) and the low density of devils recorded the risk
of mortalities from construction vehicle strikes is considered to be low.
When assessed against the Commonwealth Significant Impact Guidelines (DOTE 2013)
impact on the Tasmanian devil following mitigation (see below) are considered unlikely to
have a significant impact on this endangered species.
Spotted-tailed quoll
As no camera evidence was obtained for the spotted-tailed quoll, an estimate of the
population that will be affected by habitat loss is difficult; however, if the species is
present, it appears to be in very low numbers. Nor is the site expected to be providing
habitat for what is classified as an ‘important population’ of the species, that is necessary
for the species’ long-term survival and recovery (DOTE 2013).
It is similarly difficult to calculate the probability of vehicle strikes on the spotted-tailed
quoll. However, given the lack of records from the camera survey, and the estimated low
population density, the risk of mortalities from vehicle strikes is also considered likely to
be low.
Therefore, based on a consideration of the Australian Government’s Significant Impact
Guidelines and the implementation of mitigation (see below), the project is not likely to
have a significant impact on this vulnerable species (DOTE 2013).
Tasmanian Masked owl
No evidence of the Tasmanian masked owl was detected during the surveys and, based
on the survey findings, no direct impacts to this species are likely. However, there is
potential for individuals to colonise the project footprint prior to project commencement,
resulting in harm to individuals or nests during clearance activities.
Approximately 5.2 ha classified as high quality habitat will be removed during site
clearance. However, it is not expected that the site provides habitat for what is classified
as an ‘important population’ of this vulnerable species (DOTE 2013).
In accordance with the criteria provided in the Australian Government’s Significant Impact
Guidelines (DOTE 2013), should mitigation be implemented (see below), it is unlikely the
project will have a significant impact on this vulnerable species.
Tasmanian Azure Kingfisher
No high quality (breeding) habitat for the Tasmanian azure kingfisher will be lost during
site clearance, although approximately 9 ha of medium quality (foraging) habitat will be.
The 2013 survey identified abundant alternative habitat outside the project footprint.
Therefore, in the context of the region and based on a consideration of the Australian
Government’s Significant Impact Guidelines, the expected impacts are considered a
minor loss and the project is not considered likely to have a significant impact on this
endangered species (DOTE 2013).
Wedge-tailed Eagle & White-bellied Sea-eagle
No eagle species were observed during the ground-based surveys, nor were any nests
identified during the 2012 aerial and 2013 ground-based surveys within the close vicinity
of the project footprint. No high quality habitat will be lost during clearance, but
approximately 4.5 ha of habitat classified as medium quality potential habitat will be
removed.
98 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Based on the survey findings, no direct impacts to these species are likely. However,
there is potential for individuals to nest in the project footprint prior to project
commencement, resulting in harm to individuals during clearance activities.
Nevertheless, based on a consideration of the Australian Government’s Significant
Impact Guidelines, and the implementation of mitigation (see below), the project is not
considered likely to have a significant impact on these EPBC-listed species (DOTE 2013).
Grey Goshawk
This species was not detected during the ground-based surveys, nor were any nests
identified during the 2012 aerial and 2013 ground-based surveys within the project
footprint.
Approximately 15.5 ha of high priority habitat will be removed during vegetation
clearance, with other high priority areas to be avoided by the project.
Based on the survey findings, no direct impact to this species is predicted. However,
there is potential for individuals to colonise the project footprint prior to project
commencement, resulting in harm to individuals or nests during clearance activities.
Should mitigation be implemented (see below), it is not expected that the project will
require the disturbance or destruction of individuals of this State-listed protected species.
Migratory Species
The listed migratory species predicted to occur within the Project footprint, based on the
presence of suitable habitat, namely Latham’s snipe, white-throated needletail and satin
flycatcher, were not detected during any of the field surveys.
Based on the survey findings, the lack of any records of these species in the surrounding
area, and a consideration of the Australian Government’s Significant Impact Guidelines
(DOTE 2013), the project is not expected to have a significant impact on these migratory
species.
Mitigation
Measures to reduce the impacts on high quality vegetation communities will also benefit
threatened species that use those communities as habitats.
As discussed in Section 2.10.2, clearance will, as far as possible, be undertaken outside
the breeding seasons of threatened species (ie clearance during April, May and June
where possible). However programme constraints or weather conditions in the West
Coast may require clearance at different times of year.
The following sections describe mitigation measures that would be implemented for each
species, including where breeding season clearance is required.
Tasmanian Devil
Mitigation of impacts to the Tasmanian devil include:
Where possible avoid clearance during the main devil denning season from July to
December inclusive;
Pre-clearance survey by a trained ecologist to clarify the absence of any natal dens
and/or active dens prior to vegetation clearance. This survey will involve a visual
inspection by a suitably qualified ecologist of the key sites (marked as four potential
social dens and one log/boulder complex providing potential for a natal den)
identified by Nick Mooney in his survey in 2013. If evidence is found of potential
maternal denning activity a follow up camera survey will be implemented to confirm
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 99
den usage.
Should an active den be found prior to clearance a Devil Den Decommissioning
Plan will be implemented. Necessary permitting will be obtained and a specific plan
can only be prepared once a den is identified. However the contents of the plan are
listed in the Ecological Assessment (Appendix I).
Vehicle management on site including 40 km/h speed restrictions and restrictions
on night-time site traffic.
To prevent attracting devils and quolls, the D Dam haul road will be inspected daily
and any dead animals found on the road or verges will be removed for disposal in
the Renison domestic landfill.
No pet dogs should be on site.
In addition, woody debris generated during clearance works will be placed around the
clearance boundary (in a manner to provide structural diversity) to increase potential
denning habitat (this approach aims to replicate existing features such as the ‘log and
boulder complex’ identified as having potential habitat value in the ecological surveys).
Spotted-tailed Quoll
No additional mitigation is proposed for the spotted-tailed quoll, as the mitigation
measures outlined for the Tasmanian devil (above) will also minimise potential impacts to
the spotted-tailed quoll.
Tasmanian Masked Owl
No Tasmanian masked owls were detected. However, if clearance activities occur
between the start of October and the end of March, passive listening and observation
surveys will be undertaken in the vicinity of trees likely to provide habitat for the species
(i.e. with hollows >40 cm wide and >100 cm deep).
If present, clearance will not commence in that area until after the breeding season or the
nest is confirmed vacated.
Tasmanian Azure Kingfisher
To minimise impacts to the Tasmanian azure kingfisher, the following mitigation
measures will be implemented:
Clearance of vegetation along waterways is minimised by project design and
borrow area siting; OR
Before any clearance from September-February inclusive surveys for breeding
azure kingfishers will be undertaken. If present, no clearance will start in that area
until after the breeding season or the nest is confirmed vacated.
100 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Wedge-tailed Eagle & White-bellied Sea-eagle
Although no nests have been identified within or immediately adjacent to the site for
either of these species, there remains a risk that individuals may develop nests within the
site before construction commences. To manage this risk, clearance will be conducted
outside the eagle breeding season (July to January inclusive) where possible. Where this
is not possible, pre-clearance foot based searches of areas mapped as ‘medium’6 priority
nesting habitat will be undertaken and exclusion zones (of 500 m absolute and 1000 m
line of site) applied during the breeding season.
Grey Goshawk
To minimise potential impacts to the grey goshawk, the following mitigation measures will
be implemented:
Vegetation clearance will be avoided during the breeding season of this species
(September-February inclusive); OR
A pre-clearance check of high priority habitat for this species will be conducted, to
identify whether any individuals are currently nesting in the area. If present,
clearance will not commence in that area until the end of the breeding season and
the individual(s) have been confirmed to have vacated the nest (i.e. follow-up
check will occur).
Migratory Species
No specific mitigation is proposed for the listed migratory species predicted to occur
within the project footprint, as none are expected to utilise the site for breeding and the
project is not expected to have a significant impact on these species.
Impacts on Threatened Fauna from Disturbance by Construction Activities
Receptors
The wedge-tailed eagle and white-bellied sea-eagle are the threatened fauna species
considered most likely to be potentially impacted by noise and/or visual disturbance from
construction activities but any disturbance would likely be on free-living individuals and be
mildly disruptive at most.
Effects
There is likely to be some impact on fauna due to noise from construction activities. The
sensitivity to such activities will vary from species to species but impacts will be
temporary in nature and confined to limited areas surrounding the footprint. All of the key
species considered in this assessment are transient and would be capable of avoiding
such disturbance. This is not considered to be significant.
If blasting were to be required to extract rock from the borrow areas, it could disturbance
or distress to wildlife over a wider area, particularly if during a breeding season.
Although no eagle nests have been found on site, disturbance during construction could
affect eagles if they were to colonise the site post the ecological survey but prior to
clearance.
As discussed in Section 4.1.3 and 4.2.3 construction activities could result in impacts on
water quality including increased suspended sediment or the spill of a chemical
6 No areas were mapped as “high” priority within the footprint.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 101
contaminant in creeks downstream of the Project footprint, which may affect food
availability or drinking water quality for species that feed along watercourses.
The measures described in Section 4.1.3 and 4.2.3 will minimise the chances of a
significant pollution event during construction. Any such impact would be short term,
localised and unlikely to effect the entire foraging range of any of the threatened species
potentially on site.
Mitigation
PWS will be notified of wildlife injured during construction on the injured wildlife hotline
(03 61654305). Where a local wildlife carer is available for a given species, the animal will
be taken for treatment and rehabilitation. Injured wildlife will be treated according to the
relevant guidance from (http://dpipwe.tas.gov.au/wildlife-management/caring-for-
wildlife/injured-and-orphaned-wildlife/caring-for-orphaned-wildlife).
Mitigation measures for eagles and water quality outlined in other parts of this report will
also protect against threatened fauna impacts associated with disturbance during
construction.
Further assessment of potential impacts will be undertaken, and suitable measures
proposed, if blasting is required.
Impacts on Threatened Fauna from Encouragement of Feral Animals
Receptors
Feral animals can spread disease (especially cats and toxoplasmosis), eat native flora,
spread weeds, predate on and compete with native fauna for food and refuges. Thus, a
very wide range of native animals could be impacted by feral animals, rats and cats in
particular. Threatened fauna recorded on site considered most likely to be potentially
impacted by the presence of feral animals include:
Tasmanian devil and spotted-tailed quoll (competition with cats for food and dens
and predation on young by cats and predation of adults and young by dogs);
Azure kingfisher (predation by rats and cats);
Eagles and grey goshawk by competition with cats and dogs for food.
Effects
Mortality and displacement of common birds and mammals within the project footprint
during clearance works may result in a temporary increase in scavengers and predators
(feral dogs and/or cats) within the Project footprint.
Additional waste(s) generated by the project may also have the potential to encourage
greater numbers of feral dogs and cats in the region.
Mitigation
Feral animal trapping forms part of ongoing environmental management by BMT JV at
Renison.
Waste management measure described in Section 4.6 will prevent the encouragement of
feral animals, and no foodstuffs will be stored on site.
102 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.3.4 Operational Impacts and Mitigation
Impacts on Vegetation Communities
Receptors
Vegetation communities on the edge of the active borrow areas and the embankment
(see Figure 3-4).
Effects
There may be minor vegetation clearance required as part of operational maintenance or
fire prevention. This will generally be restricted to the footprint around D-Dam cleared
during the construction phase of the project (i.e. regrowth vegetation).
Mitigation
The following mitigation measures will be implemented during the operational phase of
the project:
Ongoing weed, disease and pest management will continue in accordance with the
Weed Management and Hygiene Plan; and
Section 8 describes the proposed measures to rehabilitate disturbed areas at site
closure.
Impacts on Threatened Fauna
Receptors
Fauna species potentially affected by operational activities are described in Section 3.5.3.
Effects
As the clearance works will take place during the construction phase, there will be no
significant impact on vegetation communities (and hence fauna habitat) during the
operational phase of the project.
There may be minor vegetation clearance required as part of operational maintenance or
fire prevention. This will generally be restricted to the footprint around D-Dam cleared
during the construction phase of the project (i.e. regrowth vegetation). It is considered
unlikely regrowth vegetation (classified as FRG community) will provide significant habitat
value(s) for threatened fauna species.
Potential impacts on aquatic fauna downstream of normal operation of the Project (i.e.
creeks draining the footprint and Lake Pieman) from operational discharges are covered
in Section 4.1.
Operation of the TSF may have a negative impact on water quality downstream of the
new TSF during operation with potential to impact upon terrestrial species which rely on
local water bodies for drinking water and food source.
This includes threatened species such as the azure king fisher or white bellied sea eagle
which could drink from or eat aquatic species from the downstream aquatic environment,
with deleterious effects if contamination were to occur.
As outlined in Sections 2.7 and 4.1.4, a series of design and management measures
have been put in place to protect downstream water quality in accordance with the State
Policy on Water Quality management 1997.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 103
As the modelling in Section 4.1.4 shows, the downstream water quality is protected and in
some instances improved from the current situation. Given the results of investigation
and modelling, the expected water quality downstream of the new TSF is predicted to be
similar to the current scenario and the potential residual risk to terrestrial threatened
fauna is low.
The measures to prevent AMD described in Section 2 and Section 4.1.4 the management
and monitoring regimes described in Sections 6 and 7, along with the closure
methodology described in Section 8 all serve to maximise the long term stability of the
TSF and minimise the potential for pollution events that could have a wide impact on the
food sources of threatened species. The operation of the TSF generates very few traffic
movements and the risk of traffic impacts to species such as the Tasmanian devil and
spotted-tailed quoll will be negligible.
Mitigation
No further mitigation is proposed for threatened fauna species during the operational
phase of the project, as the mitigation measures outlined for vegetation communities
(above) as well as all the mitigation measures to protect short and long term water quality
will also minimise potential impacts to threatened fauna.
Risks, mitigation measures, monitoring and corrective action with regard to water quality
management are addressed in Sections 4.1 and 4.2. These measures will protect against
downstream water quality degradation, which could in turn affect fauna species relying on
local water sources for food and water.
Despite the low risk, to minimise potential for vehicular collision with devils and quolls,
daily inspection of the haul road for animal carcasses will continue during the operational
phase (with any carcasses found removal daily to the local landfill).
4.3.5 Monitoring
Terrestrial Ecology Monitoring
Monitoring will be undertaken prior to habitat clearance. As described above, biodiversity
monitoring will be dependent on the season in which vegetation clearance occurs. Pre-
clearance surveys by trained ecologists will include:
Tasmanian devil visual surveys prior to clearance at any time of year with follow up
camera survey if potential maternal denning is identified. Visual survey to include
the key sites (marked as four potential social dens and one log/boulder complex
providing potential for a natal den) identified by Nick Mooney in his survey in 2013;
Passive listening and observation surveys for Tasmanian masked owl if clearance
is between start of October and the end of March;
Pre-clearance foot based searches for wedge –tailed eagle and white bellied sea
eagle in areas mapped as ‘medium’7 priority nesting habitat and exclusion zones
(of 500m absolute and 1000m line of site) if clearance proposed during breeding
season.
Breeding surveys for azure kingfishers if clearance is between the start of
September and the end of February; and
Pre-clearance check of high priority habitat for grey goshawk if clearance is
between the start of September and the end of February.
7 No areas were mapped as “high” priority within the footprint.
104 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.3.6 Management commitments
Vegetation Communities
Commitment 12 Vegetation clearance or damage outside the footprint will be avoided by flagging, fencing and site access plans.
Commitment 13 Where possible, given the nature of the clay resource, borrow areas used will start in existing cleared, disturbed areas and end at the least disturbed areas, so that any reductions in material demand will lead to reductions in clearance of the highest quality habitats.
Commitment 14 Storage of materials and/or machinery will utilise existing cleared areas.
Commitment 15 Haul road from the borrow areas will be created by widening existing survey track.
Commitment 16 A weed control and hygiene plan will be implemented during the construction and operational phases.
Fauna
Commitment 17 Construction site vehicle movements will be limited to daytime hours and speeds of less than 40 km/h.
Commitment 18 If possible, vegetation clearance will be undertaken in April, May or June which has the lowest potential for breeding of threatened species.
Commitment 19 Before any clearance a devil and quoll visual den survey will be undertaken to identify any active use of the key potential denning features previously identified.
Commitment 20 Should an active den be found prior to clearance a Devil Den Decommissioning Plan will be implemented and relevant permits sought.
Commitment 21 During both construction and operation, the site roads will be checked daily for presence of dead animals and any carcasses found removed immediately and disposed of at the local landfill.
Commitment 22 No pet dogs will be kept on the construction site.
Commitment 23 Woody debris generated will be used to create potential denning habitat around the clearance boundary.
Commitment 24 Pre clearance surveys for Tasmanian masked owl nesting will be undertaken before any clearance between September and the end of March. If present, no clearance will start in that area until after the breeding season or the nest is confirmed vacated.
Commitment 25 Before any clearance from September to February inclusive surveys for breeding azure kingfishers will be undertaken. If present, no clearance will start in that area until after the breeding season or the nest is confirmed vacated.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 105
Commitment 26 Before any clearance from July to January inclusive a foot based survey for eagles nest will be undertaken within areas mapped as medium priority nesting habitat. If present, no clearance will start in that area (500 m absolute and 1000 m line of sight) until after the breeding season or the nest is confirmed vacated.
Commitment 27 Before any clearance from September to February inclusive surveys for breeding grey goshawk will be undertaken. If present, no clearance will start in that area until after the breeding season or the nest is confirmed vacated.
Commitment 28 Existing feral animal trapping executed under the BMT Environmental Management Plan will continue during the construction and operation of D Dam.
Commitment 29 PWS will be notified of wildlife injured during construction. Where a local wildlife carer is available for a given species, the animal will be taken for treatment and rehabilitation. Injured wildlife will be treated according to the relevant guidance from PWS.
106 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.4 Air Emissions
4.4.1 Legislative, Policy and Performance Requirements
The Tasmanian Environmental Protection Policy (Air Quality) 2004 (EPP) provides a
framework for the management and regulation of both point and diffuse sources of
emissions to air, and for pollutants with the potential to cause environmental harm. This
EPP is made pursuant to the provisions of section 96A-96O of EMPCA.
The environmental values covered by this policy are:
The life, health and well-being of humans at present and in the future;
The life, health and well-being of other forms of life, including the present and
future health, wellbeing and integrity of ecosystems and ecological processes;
Visual amenity; and
The useful life and aesthetic appearance of buildings, structures, property and
materials.
The key performance requirements relate to maintenance of air quality during the
construction and operational phases to minimise potential impacts to site workers, local
residents and the environment.
In addition to these general requirements, the current BMT JV Protection Notice (EPN
7092/2) requires that “dust emissions from roads, disturbed areas, storage heaps, or
machinery on the land must be controlled to prevent environmental nuisance”.
4.4.2 Existing Conditions
There are no known data on local air quality for the D Dam footprint. However the site is
in a remote part of Western Tasmania and air quality is generally high.
Occupational dust monitoring is undertaken at the Processing Plant site and, according to
the 2009 EMP, consistently meets occupational health standards.
4.4.3 Construction Impacts and Mitigation
Receptors
There are no nearby human receptors other than those at the Renison Bell Tin Mine.
Effects
Impacts associated with construction are expected to principally result from dust and
plant emissions. High local rainfall (See Section 3.4.2) will limit the potential for dust
emission from stockpiled materials or roads. Ordinarily, dust impacts on sensitive human
or ecological receptors is expected to be negligible though impacts on ecological
receptors may arise during a prolonged period of dry weather.
Mitigation
Dust suppression will be employed in response to any visible plumes of dust during
construction. The management of dust emissions from the site will comprise:
Dampening of surfaces with bowser runs in response to observed dust plumes;
Maintaining a speed limit of 40 km/h for traffic on D Dam construction haul road;
Sheeting of truck loads on D Dam construction haul road during dry and windy
conditions;
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 107
Vehicle washdown prior to leaving the site; and
Progressive rehabilitation of areas of ground disturbance and stockpiled topsoil.
All construction vehicles and plant will be maintained to keep emissions to a minimum.
As discussed in Section 2.10, there will be no in-situ burning of cleared vegetation.
4.4.4 Operational Impacts and Mitigation
Receptors
As for construction.
Effects
During operation there may be limited air quality impacts wind-blown dust or tailings
dispersion.
Mitigation
Dispersion of tailings via wind movement will be managed by:
Maintaining wet conditions in the tailings (this is required to prevent acidification
and is described in Section 2.2.10);
Placement of tailings via end point discharge around the embankment. This allows
coarser tailings to be placed at the embankment crest, thereby creating a firmer
base for possible future dam lifts and minimising the potential for wind-blown
tailings (see Section 2.11.4); and
Upon closure the tailings will be flooded. If a soil and water cover approach is
adopted for closure (see Section 8) then it is anticipated that rapid vegetation
regrowth (as has been experienced on the A and B Dams during the period in
which they were decommissioned) is anticipated to provide an effective control on
dust generation.
4.4.5 Monitoring
Construction
Dust emissions will be monitored visually as part of daily construction surveillance.
Operation
Dust emissions will be monitored visually as part of routine operational environmental
management surveillance.
4.4.6 Management Commitments
Commitment 30 Dust during construction will be managed by limiting vehicle speeds (40 km/hr limit within the dam site), vehicle wash down prior to leaving the site; and damping of roads and covering of vehicles when daily visual monitoring indicates visible dust plumes.
Commitment 31 All construction vehicles and plant will be maintained to keep emissions to a minimum.
108 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.5 Noise Emissions
4.5.1 Legislative, Policy and Performance Requirements
The key legislation, policy and guidelines of relevance to noise management in Tasmania
are:
EMPCA;
Environmental Management and Pollution Control (Miscellaneous Noise)
Regulations 2004 (EMPCR);
Environment Protection Policy (Noise) 2009;
Noise Measurement Procedures Manual (NMPM), July 2004.
4.5.2 Existing Conditions
The D Dam footprint is in close proximity to existing TSFs and hence the pre-existing
local noise relates to vehicle movement around the existing dams which is infrequent and
low level.
4.5.3 Construction Impacts and Mitigation
Receptors
The nearest residence to the D Dam footprint is approximately 5 km along the Murchison
Highway towards Rosebery. Beyond this, the nearest township is that of Rosebery,
approximately 10 km from Renison Bell.
Effects
There is likely to be noise generated by vehicles and machinery during daylight hours
only. Given the limited nature of construction noise and the significant distance to the
nearest human sensitive receptors, noise impact during construction is expected to be
limited.
Blasting may be required as part of works to extract rock and other materials for Borrow
areas. Distance to the nearest residence means that there is little chance of noise or
vibration impacts from blasting on external human receptors.
Construction activities may result in disturbance to wildlife, these are discussed in 0.
Mitigation
Construction activities will comply with occupational health and safety requirements for
noise under the Work Health and Safety Act 2012.
Machinery will be regularly inspected and maintained.
Blasting, if required, would be undertaken subject to the following:
A blasting permit and any conditions;
Blasting design and implementation will be subject to quality control;
Blasting distances and velocities will be limited to prevent potential impacts on dam
stability.
Blasting design and implementation will be undertaken by a qualified and
experienced person.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 109
4.5.4 Operational Impacts and Mitigation
During D Dam operation, noise impacts will be limited to vehicle and machinery
movement and pumping equipment consistent with existing operations. Operational noise
impacts are considered to be negligible.
4.5.5 Monitoring
Construction
Where blasting is required, noise, vibration and air overpressure will be monitored during
blasting and permits will be sought.
Operation
No significant operational noise emissions are anticipated.
4.5.6 Management Commitments
Commitment 32 Permits will be sought for any blasting required.
110 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.6 Solid and Controlled Waste Management
4.6.1 Legislative, Policy and Performance Requirements
The key legislation, policy and guidelines of relevance to the management of solid and
controlled wastes in Tasmania are:
EMPCA;
Environmental Management and Pollution Control (Waste Management)
Regulations 2010; and
Used Packaging Materials NEPM.
The key performance requirements, as related to the legislation outlined above are:
Approval must be sought prior to controlled wastes being transported from the site;
Controlled wastes must be removed from the site by an approved controlled waste
transporter; and
Controlled wastes must be disposed of at an approved disposal facility.
Waste management during construction and operation will generally be in line with the
principles of the waste hierarchy.
4.6.2 Construction Impacts and Mitigation
Effects
Estimated construction waste generation is presented in Table 4-7.
Table 4-7 D Dam Construction (and borrow area) Waste Estimate
Component Waste type Waste generated*
Project Footprint Timber removal Timber removed for sale / use
Embankment and borrow area
Stripped of all soils/vegetation (approx. 0.3 m)
133,500 m3
TSF Storage area footprint
Vegetation clearance (soil already stripped of the storage area footprint)
66,000 m3 (assuming 0.2 m depth cleared vegetation)*
All General construction activities Small amounts of construction consumables, packaging
* A rough estimate which may overestimate given that some of the footprint has existing borrows which have been stripped previously
Other than this only minor solid waste generation is expected from construction
consumables and packaging.
There are no controlled wastes to be generated by the Project. Any vehicle or plant
maintenance which may generate waste oils and lubricants will be conducted at the
existing mill site and any resulting wastes treated through the existing system.
Mitigation
Construction waste storage and disposal will be based on the waste management
hierarchy:
Avoid – prevent the generation of waste;
Reuse – reuse wastes for a productive purpose;
Recovery of energy - use wastes as fuel or energy source where possible;
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 111
Treat - prevent or minimise environmental risks before disposal; and
Dispose – deposit wastes to an approved landfill.
Subject to permitting, the useable timber will be extracted and the remaining vegetation
will be cleared using bulldozers to the edge of site.
No burning of cleared vegetation is proposed.
Vegetation waste and organic material will be pushed into berms downslope of the
storage area as sediment traps. This can later be mulched for use capping and
rehabilitation of A, B and C Dams.
Topsoil extracted from Project the footprint will be segregated and either transferred to
rehabilitation sites for A, B and C Dams, or be stockpiled according to guidelines in the
Quarry Code of Practice (DPIWE, 1999) for subsequent reuse.
Any non-controlled general construction waste will be stored within the Project footprint in
a temporary, segregated area, with sealed bins for putrescible waste. This will be
regularly collected and either recycled or sent to landfilled along with the existing mine
waste and recycling facilities.
4.6.3 Operational Impacts and Mitigation
The potential solid and controlled wastes expected during the operational phase include:
The tailings and stored PAF waste rock, as described in Section 2; and
Small (non-significant) quantities of miscellaneous waste generated during
operation of the TSF such as consumables and replacement parts for
equipment, vehicles and monitoring activities. Any such minor wastes will be
transported back to the mill site for handling and disposal in line with existing
practices.
4.6.4 Monitoring
Construction
The quantities and resulting destination of all significant wastes during construction will be
recorded.
Operation
The TSF is not expected to generate solid waste during the operation.
4.6.5 Management commitments
Commitment 33 Vegetation waste will be stored for later use.
Commitment 34 Subject to permitting, the useable timber will be extracted and the remaining vegetation will be cleared using bulldozers to the edge of site.
Commitment 35 No burning of cleared vegetation is proposed.
Commitment 36 Where practical, topsoil extracted from the embankment footprint will be segregated for storage and reuse.
Commitment 37 Construction waste (not including soil and vegetation) will be stored securely to prevent escape and removed from site regularly.
112 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.7 Dangerous Goods
4.7.1 Legislative, Policy and Performance Requirements
D Dam construction and operation must fulfil the requirements of the following legislation
and policy in relation to dangerous goods:
Australian Code for the Transport of Dangerous Goods by Road and Rail;
Globally Harmonized System of Classification and Labelling of Chemicals (GHS);
Dangerous Substances (Safe Handling) Act 2005 and associated regulations;
Australian Dangerous Goods Code Edition 7.3 (2014); and
Relevant Australian Standards (e.g. AS 1940 (The storage and handling of
flammable and combustible liquids) and AS 3780 (The storage and handling of
corrosive substances).
4.7.2 Construction Impacts and Mitigation
During the construction period the only dangerous goods to be used on site are
explosives.
Effects
Explosives will be used on site. Small quantities of fuel, lubricants and other chemicals
may be used and stored on-site during the D Dam construction.
Impact of dangerous liquids (namely fuels and oils) during construction is discussed in
Section 4.1.3.
Mitigation
A register of any dangerous goods to be transported, stored and used during construction
will be maintained.
Dangerous materials will be stored in secure locations at the Renison Process plant, and
will be handled in accordance with the relevant standards and legislative requirements.
Storage, handling and use of explosives will comply with the relevant requirements of the
Explosives Act 2012 and regulations, and risk of impact on the health and safety of
workers is very low.
4.7.3 Operational Impacts and Mitigation
The key hazardous substance that will be used during operation is hydrated lime as
discussed in Section 2.7.1.
Lime will be stored within the existing secure hazardous materials storage area at the
Processing Plant and no additional lime will be stored at D Dam.
All storage and handling will be undertaken in accordance with EPN 7092/2 and EMP
(2013) as is currently undertaken. Therefore the risk of accidental releases of hydrated
lime to the environment is unchanged by D Dam operations.
4.7.4 Monitoring
Construction
A register of any dangerous goods to be transported, stored and used during construction
will be maintained.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 113
Operation
Existing recording of hydrated lime use and storage will be continued.
4.7.5 Management Commitments
Commitment 38 A register of any dangerous goods used as part of the construction will be prepared.
4.8 Geo-conservation
4.8.1 Legislative, Policy and Performance Requirements
Tasmania does not have legally defined requirements for protection of geo-heritage.
While having no statutory basis, the D Dam Project Specific Guidelines issued under
EMPCA (Section 1.7.1), request an assessment of the effects on identified features from
the Tasmanian Geo-conservation Database.
4.8.2 Existing Conditions
Existing conditions are described in Section 3.4.3 and in Appendix E. In particular, the
NVA shows the footprint is contained within the Central Highlands Cainozoic Glacial
Area. Some distance to the south (approximately 5 km) lies an area mapped as Western
Tasmania Blanket Bog.
The D Dam and borrow areas footprint contains features consistent with the Central
Highlands Cainozoic Glacial Area designation in the Geo-conservation Database
including fluvial, glacial and lacustrine sediments and features such as boulder erratics
and drop stones.
Much of the site of D-Dam, and the westernmost of the potential borrow areas, has been
stripped of the majority of the surface sediment and consequently has retained little
natural value although to the north and eastern limits of the area site showed a relatively
complete record of the glacial history of the site.
There was no evidence of Western Tasmanian Blanket Bog within or immediately
adjacent the project footprint.
4.8.3 Construction Impacts and Mitigation
Receptors
Shallow Pleistocene deposits in the footprint of D Dam and borrow areas will be affected.
Effects
Apart from the westernmost potential borrow area which has been subject to previous
quarrying, the zones being investigated for borrow areas are likely to have experienced
less disturbance than the footprint of the TSF. Removal of glacial deposits in the footprint
of the final borrow will be complete and hence mitigation will not be possible.
However, the Central Highlands Late Cenozoic Glacial geo-conservation area covers
hundreds of square kilometres of which the footprint is a small, peripheral part. Hence it is
not anticipated that their removal will have a significant impact on the geo-heritage area
as a whole.
There are no expected impacts on the nearby Western Tasmania Blanket Bogs.
114 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.8.4 Operational Impacts and Mitigation
Any use of borrow areas from operational of the TSF will not entail further impacts on
geomorphology or geoheritage.
4.8.5 Monitoring
No monitoring proposed.
4.9 Greenhouse Gases and Ozone Depleting Substances
Greenhouse gas emissions are controlled and reported through a number of legislative
tools at a National level. The Commonwealth Government has recently repealed the
Carbon Tax and the status of clean energy at a Commonwealth level is currently under
alteration.
At a State level, Climate Smart Tasmania; A 2020 Climate Change Strategy and the
Climate Change (State Action) Act 2008 set outs the priority action areas for Tasmania’s
response to climate change from 2011 going forward.
4.9.1 Construction Impacts and Mitigation
Effects
Unavoidable greenhouse gas (GHG) production from construction activities relates to the
operation of machinery such as dump trucks, excavators, rollers, graders, bulldozers, and
water carts.
The other potential impact involves the clearance of the D Dam footprint. This is also an
unavoidable impact associated with D Dam construction.
Mitigation
The primary mitigation is reduction of emissions by the use of well-maintained efficient
machinery.
BMT JV supports good environmental practice and aims to reduce greenhouse gas
emissions and the use of energy where it is practical to do so. This is supported by the
BMT JV Environmental Policy Statement aim to “Have continuous improvement through
ongoing assessment of our environmental performance”.
4.9.2 Operational Impacts and Mitigation
The sulfides present in the tailings limit methane production from breakdown of organic
reagents. Sulfides will be maintained under saturated, anoxic conditions. There is little
potential for production of acid requiring neutralization with carbonates, a reaction which
produces carbon dioxide. As such there is anticipated to be a negligible amount of GHG
production associated with D Dam operation.
4.9.3 Monitoring
No monitoring proposed.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 115
4.10 Heritage
4.10.1 Legislative, Policy and Performance Requirements
Aboriginal and European Heritage values in Tasmania are protected by a range of
legislation and policy, the key relevant documents include:
Aboriginal Relics Act 1975;
Historic Cultural Heritage Act 1995.
Aboriginal Heritage
The Aboriginal Relics Act 1975 governs the treatment of Aboriginal relics and protected
sites in Tasmania. It is an offence to destroy, damage, deface, conceal or otherwise
interfere with a relic. Aboriginal cultural heritage is defined as “any place, site or object
made or created by, or bearing the signs of the activities of, the original inhabitants of
Australia or descendants of such inhabitants in or before 1876 in Tasmania”.
European Heritage
In 2008 Heritage Tasmania indicated that no site studies were required for D Dam.
Under the Historic Cultural Heritage Act 1995, a person must not carry out any works in
relation to a registered place or a place within a heritage area which may affect the
historic cultural significance of the place unless the works are approved by the Heritage
Council. Because the D Dam footprint is not entered in the Heritage Register, no approval
from the Heritage Council is needed.
Under the West Coast Interim Planning Scheme 2013, the use or development within the
boundaries of a site listed in Table 19.1 of the Scheme, or immediately adjacent to a
listed site is discretionary. The development site is not included in Table 19.1 of the
Scheme and there are no listed places immediately adjacent. Therefore, the Heritage
Code provisions of the Scheme are not relevant to the D Dam.
4.10.2 Existing Conditions
Existing conditions are described in Section 3.2 and 3.3 and in Appendix C and Appendix
D. In summary, these show:
No recorded or significant potential for aboriginal heritage within the project
footprint.
No listed historical heritage, though some potential for heritage related to early
European mineral prospecting.
4.10.3 Construction Impacts and Mitigation
Receptors
There will be no impact on known aboriginal remains and no listed heritage features will
be disturbed by the activities.
Effects
Aboriginal Heritage
Any ground disturbing works have the potential to uncover sub-surface Aboriginal sites,
although the risk is considered to be low.
116 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
European Heritage
The 2013 heritage review (see Appendix C reinforced the understanding of the high
significance of the broader Renison Bell area in Tasmania’s mining history, however
identifies little potential for significant heritage within the disturbance footprint of D Dam
itself.
There is the possibility of disturbance of remains associated with early mining exploration
and timber getting activities.
Mitigation
As the proposal does not include any identified historic heritage places or sites, impacts
are not anticipated and no specific mitigation measures are considered necessary.
If a suspected Aboriginal or European heritage feature is uncovered during clearance or
excavation work, work will cease, Aboriginal Heritage Tasmania or Heritage Tasmania
respectively will be notified, with arrangements made for identification of the feature.
An Unanticipated Discovery Plan will be describing the monitoring and management of
site clearance and ground disturbance for unanticipated European heritage features and
sub-surface Aboriginal sites, will include:
Identification sheets for operators;
Procedures to cease work should such materials be identified;
Procedures for immediate notification of Aboriginal Heritage Tasmania following
the identification of such materials.
4.10.4 Operational Impacts and Mitigation
There are no anticipated operational impacts to heritage values.
4.10.5 Monitoring
Construction
Monitoring for European and Aboriginal heritage will be undertaken by the construction
contractor during all ground disturbing construction works.
Operation
No operational monitoring is proposed.
4.10.6 Management Commitments
Commitment 39 Monitoring will be undertaken by the construction contractor during all ground disturbing construction works, and if any sites are identified works will cease.
Commitment 40 If a suspected heritage feature is discovered, work will cease, AHT or HT will be notified and arrangements made for identification of the feature.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 117
4.11 Land Use and Development
4.11.1 Legislative and Policy Requirements
The key legislative and policy instruments relating to land use impacts for this Project
include:
Land Use and Planning Act 1993;
West Coast Interim Planning Scheme 2013.
4.11.2 Existing Conditions
Land within the project footprint is mainly native forest or native regrowth, with some
areas of land cleared for mining exploration and materials pits for previous mining related
infrastructure.
The Project footprint lies mainly on Crown land with a small portion falling within an area
privately owned by BMT JV. The Project footprint sits within the Renison Regional
Reserve and is designated as an Environmental Management Zone in the West Coast
Interim Planning Scheme 2013.
Section 3.1 contains a full description of existing planning and land use.
4.11.3 Construction Impacts and Mitigation
While there may be some minor temporary sites, features or areas of clearance, the
majority of land affected by the Project footprint, including the borrow areas and
associated haul road, will be affected in the long term or permanently. Consequently
Land use impacts are discussed in Section 4.11.4.
4.11.4 Operational Impacts and Mitigation
Effects
D Dam will change land use on site from mainly undeveloped native vegetation to
dedicated mining waste storage. The planning assessment in Appendix B examines the
implications of this change in terms of planning policy. The assessment conclusions are
summarised in Table 4-8.
118 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Table 4-8 Planning Policy Compliance Summary
Planning Scheme Clause
Policy description Compliant with Policy
Environmental Management Zone
29.1.1 29.1.1.1 To provide for the protection, conservation and management of areas with significant ecological, scientific, cultural or aesthetic value, or with a significant likelihood of risk from a natural hazard. 29.1.1.2 To only allow for complementary use or development where consistent with any strategies for protection and management.
Yes
29.1.3 Desired Future Character Statements – Clause 29.1.3 Yes
29.3.1 and 29.4.1
Use in a statutory conservation reserve – Yes
29.3.2 Discretionary Permit Use Yes
29.4.3 Location and configuration of development Yes
Clearing and Conversion of Vegetation Code – Schedule E3
E3.6.1 Protection of a threatened native vegetation community or native vegetation providing habitat for a threatened species
Yes
E3.6.2 Clearing of vegetation on land of scenic or landscape value
Yes
E3.6.3 Clearing of vegetation on land susceptible to landslide Yes
Change in Ground Level Code – Schedule E4
E4.6.1 Change in existing ground level or natural ground level Yes
Hazard Management Code – Schedule E6
E6.6.2 Development on land exposed to a natural hazard Yes
Traffic Generating Use and Parking Code – Schedule E9
E9.6.1 Road access Yes
E.9.6.2 Design of vehicle parking and loading areas Yes
Water and Waterways Code - Schedule E10
E10.6.1 Proximity to a water body, watercourse or wetland Yes
Mitigation
Compliance of the Project against each of the land use and development policy
requirements listed in Table 4-8 requires mitigation measures described under different
topic headings in Section 4 of the DPEMP.
4.11.5 Management Commitments
Management commitments aimed at compliance with land use and development policy
are described under different topic headings in Section 4 of the DPEMP, depending on
the nature of the policy.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 119
4.12 Visual Effects
4.12.1 Legislative, Policy and Performance Requirements
The key legislative document addressing visual impacts in the area is the West Coast
Interim Planning Scheme 2013. The broad requirements of the Scheme are described in
Section 3.1 and Appendix B.
The Stated purpose of the ‘Environmental Management Zone’ defined within section 29
of the plan is ‘to provide for the protection. Conservation and management of areas with
significant. aesthetic value, …’ and to ‘protect significant geological features, natural
landforms, and aesthetic or scenic landscape…’.
Specific visual landscape objectives for the applied to the Renison lease within the plan
are:
Acceptable solutions in 29.4.3 of the Scheme relate to buildings and utility structures and
not extractive industry infrastructure.
However the Project can be assessed against the following Local Objectives:
Local Area Objectives – Clause 29.1.2 protect significant geological features,
natural landforms, and aesthetic or scenic landscape, including within the coastline
and waterways;
Desired Future Character Statements – Clause 29.1.3 is in accordance with best
practice management principles for protection and conservation of an area of
significant ecological, scientific, cultural or aesthetic value;
Location and configuration of development– Clause 29.4.3 Top of development
must be ‘Not less than 15 m below the level of any adjoining ridgeline’ and top of
development must be ‘below the canopy level of any adjacent forest or woodland
vegetation’
Clearing of vegetation on land of scenic or landscape value – Clause E3.6.2 ‘Clearing and conversion of native vegetation and any change in natural ground
level must not occur on any part of a site outside the designated building area.’;
‘Rehabilitation must use vegetation of a type consistent with the native vegetation
of the locality’.
4.12.2 Existing Conditions
Although the Renison Bell Tin Mine is adjacent to the Murchison Highway, the D Dam
footprint is relatively isolated given the separation distance and topography.
Nonetheless, the area between the Murchison Highway and Lake Pieman has been
substantially altered through mining activity, including the existing TSFs, A, B and C Dam.
Views from potential vantage points along the highway are also screened by existing
vegetation and embankments along the roadside verge, buildings associated with the
processing plant and existing native vegetation in the landscape surrounding the D Dam
footprint.
There is a relatively small break in the roadside vegetation to the east of the entrance to
the main car park associated with the processing plant. The bulk store building sits on a
bench below the highway at this point, allowing for views over the plant.
Figure 4-3 shows screening of views of the TSF location from the Process Plant,
vegetation and topography.
120 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
A description of the existing visual setting and likely visual impacts associated with D
Dam has been undertaken using aerial photography, 1:25,000 topographic maps and
contour information shown on the plans which accompany the proposal and digital
photographs from vantage points.
Figure 4-3 View Towards D Dam from Processing Plant Entrance
The hills on the southern side of the Murchison Highway from the processing plant offer a
potential vantage point to the D Dam footprint, however as this area is part of the mine
workings it is not generally accessible.
The Ring River Road follows the ridge on the eastern bank of the Ring River down to a
boat ramp close to ‘confluence’ with Lake Pieman. The Emu Bay Railway also crosses
the river near this point.
The west bank of the Ring River would be visible from this location (albeit through dense
vegetation), but the crest is largely hidden by extensive native vegetation.
Most of Ring River Road is constructed along the crest of a hill towards the east at
around 170 m AHD. Additionally, Argent Track is constructed along an east facing hillside
to the west above 200 m AHD. Given that both roads are constructed within State Forest
it is expected that vegetation adjacent to the verges would restrict views. In any event,
they are not in an area frequented by tourists or visitors.
Pieman Road is approximately 2 km to the north of the D Dam footprint, on the opposite
side of Lake Pieman also surrounded by State Forest. Forestry tracks extend from the
south of the road, although they terminate well before the hillsides directly above the lake.
As a result, there is limited visibility from this direction.
4.12.3 Construction Impacts and Mitigation
As they are generally long term or permanent effects, impacts from vegetation removal
and placement of the embankment are considered under operation below.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 121
Dust disturbed during construction has the potential to be viewed off-site, from areas such
as Murchison Highway, surrounding State Forest Road (including Ring River Road and
Argent Track), Lake Pieman and Ring River. Dust control is covered under Air quality
(see Section 4.1).
4.12.4 Operational Impacts and Mitigation
Receptors
The receptors affected by visual impacts are people whose visual environment could be
detrimentally affected by the presence of D Dam. Workers on the Renison mine site
represent low sensitivity receptors since they are surrounded by mining infrastructure and
areas disturbed by it.
High sensitivity receptors are therefore restricted to members of the public, looking
towards the footprint at from points from which D Dam would be visible.
Effects
The clearance of the site, construction of a new embankment and gradual filling with
tailings will significantly alter the local landscape within the Renison lease area by:
Removal of vegetation;
Raising the ground level;
Construction of an embankment;
Creation of a large tailings pond.
The embankment crest will ultimately reach 180 m AHD. Its maximum height will
consequently be 50 m from natural ground level, although this will only occur over the
deep valley formed by the tributary of Lake Pieman. The embankment will be around 15
m in north-western portion and 20 m in the north east, declining to 5 m along the high
point of the crest of the eastern hillside above Ring River. The ultimate maximum height
of the decant embankment is 15 metres.
However the site is not easily visible from publically accessible locations. The site is
setback a minimum of 1.5 km from the highway downslope and at a lower level to the
existing TSFs. The existing processing plant, natural topography and native vegetation
(including that along the roadside verge) provide a visual screen.
Although views may be possible from elevated positions outside the lease, there are no
roads or paths to allow access to these points, and elevated positions are tree covered
which would also restrict views.
Lake Pieman
There may be broken view of the D Dam embankment for boat users on Lake Pieman.
However most of the northern D Dam embankment will not be visible from Lake Pieman.
The steep hillside upwards from the lake is followed by a convex slope in the upper
reaches leading to a small plateau just above 165 m AHD. The northern embankment is
setback approximately 200 m from the northern extent of the 165 m contour, and a
minimum of 500 m from Lake Pieman. This topography, along with dense vegetation
along the lakeside, will restrict sight lines from the lake.
It is possible that there would be views of the proposed site from the valley of the Lake
Pieman tributary. These would be restricted to a small area only, particularly given the
curve which exits in the initial section of the valley and the natural vegetation cover. The
122 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
north eastern corner of the D Dam embankment has the potential to be seen from a wider
area within Lake Pieman and Ring River given the more moderate natural hill slopes
which exist, forming a concave shape in some sections, however this impact would be
still be minimal given the small number of potential receptors.
The borrow areas affect the ridge lines above Lake Pieman. The C Dam Borrow Area
affects a ridge which is set back several hundred metres and would be obscured from
views from the Lake by other slopes except in a relatively small area of the Lake. The
West Pieman Borrow Area, and particularly the northern most extent, is more prominent
and may be visible from the lake and further afield. However views of both pits would be
largely, if not entirely, obscured by the dense forest surrounding them.
Ring River
The existing native vegetation near the top of the hillside above Ring River is likely to
screen the eastern embankment. At one point near the central section, the natural
topography rises to the 180 m contour in front of the embankment when viewed from this
location, which will also restrict views.
Mitigation
Due to the limited visibility of the project to the public, no operational phase screening is
proposed.
Closure planning for D Dam will include native vegetation planting of the embankment.
Other components of the site, haul road, borrow area will be revegetated with native
species. Further detail on closure rehabilitation can be found in Section 8).
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 123
4.13 Socio-economic Issues
4.13.1 Legislative and Policy Requirements
4.13.2 Existing Conditions
A summary of existing socio economic conditions is contained in Section 3.8.
4.13.3 Construction Impacts and Mitigation
Receptors
The receptors of socioeconomic impacts from the development are those people, largely
within the local area (but also in the State as a whole) who are potentially impacted by the
Project either in economic terms or in terms of changes to social conditions or community
facilities.
Effects
The total capital investment for D Dam is estimated at $11 M. This investment will contribute to local and State labour markets as construction will require a contractor, likely to be based in one of the major population centres (e.g. Burnie, Devonport or Launceston). A broad estimate of construction job creation is 20 full time equivalent positions for 6 months.
The provision of the TSF will allow the ongoing operation of the mine for some 16 year, therefore exerting a considerable positive effect on associated up and downstream industries. The ongoing operation of the mine over this period has significant positive implications for the local community and economy.
Construction of the culvert beneath the Emu Bay railway line will be undertaken by a
contractor. No impacts to the rail line are expected as a result of culvert construction.
The majority of raw materials required for construction will be sourced from within the footprint.
As D Dam is within the existing Bluestone Mining Lease, there are no adverse effects anticipated for surrounding land values.
4.13.4 Operational Impacts and Mitigation
During operation, there are unlikely to be any additional staff employed as a result of D Dam. D Dam operation is likely to be undertaken by the existing BMT JV operational staff.
A large proportion of the local community are employed at the Renison Tin Operation, or other local mines. Hence, although the D Dam itself will not have a significant impact on the local community it will allow the ongoing operation of the mine and hence retention of existing jobs and flow on industries.
124 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.14 Health, Safety and Environmental Hazard Analysis
4.14.1 Legislative, Policy and Performance Requirements
TSFs in Tasmania are regulated under the:
Water Management Act 1999;
Water Management (Safety of Dams) Regulations 2003.
Additionally, the construction and operation of the TSF must comply with the
Tasmanian Work Health and Safety Act 2012 and Regulations 2012;
Mines Work Health and Safety (Supplementary Requirements) Act 2013 and Regulations 2013;
AS/NZS 4804:2001 Occupational Health and Safety Management Systems;
EPN 7092/2;
Fire Services Act 1979.
4.14.2 Hazard Analysis and Risk Assessment
GHD undertook two risk assessments during the development of this proposal:
A sustainability risk assessment addressing key environmental risks associated
with the construction and operational and decommission phases, as outlined below
and included in Appendix P; and
An ANCOLD risk assessment in relation to dam safety and stability, described in
Sections 3 and 7 of Appendix N and summarised below. It should be noted that
some aspects of the design (see Section 2), such as the borrow areas, have
changed since the issue of preliminary design report. However aspects relating to
the hazard and rating assessment for the embankment remain applicable.
Sustainability Risk Assessment
The analysis of hazards is central to the effective management of health, safety and
environmental risks. This section provides the results of the hazard analysis and risk
assessment that was conducted by GHD to identify and manage environmental hazards
during the concept development phase, while considering the construction and
operational phases. The assessment is inclusive of the risks associated with the
construction, ongoing operation and decommissioning of the facility, and only considers
credible risks.
The process considered hazards leading to potential risks, with evaluation of the
likelihood and consequence of events being risk ranked according to a Sustainability Risk
Assessment Tool.
ANCOLD Risk Assessment
The ANCOLD Guidelines on Assessment of the Consequences of Dam Failure is the risk
tool used to assess the consequence of failure. GHD undertook a conservative
assessment of the relevant categories from the ANCOLD guidelines.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 125
4.14.3 Construction Impacts and Mitigation
Receptors
People and environmental values near the project footprint. The construction site is within the existing mining lease and the operational areas surrounding A, B and C Dams. In this regard, the site is not publicly accessible and additional fencing during construction is not considered necessary.
Effects
A preliminary assessment of construction health and safety risk is included in Appendix P.
Key construction health and safety risks identified in the assessment are:
Fire;
Sediment mobilisation into receiving waters;
Hazardous material spills;
Erosion of surrounding land;
Landslide.
Mitigation
General Construction Health and Safety
D Dam construction contractors will be required to work in accordance with the Tasmanian Workplace Health and Safety Act and Regulations 2012 and AS 4804 Occupational Health and Safety Management Systems.
Contractors will be required to prepare and implement a Health and Safety Management Plan (HSMP) specific to their role in D Dam construction (this may be required to be submitted to the Workplace Safety Division). This will include:
A construction hazard and risk assessment;
Documented risk management measures;
Measures for record keeping during construction;
Process for incident notification to the relevant competent authority following an
accident/incident.
Fire Risk
Fire risk will be managed according to the existing BMT JV Emergency Management Plan
(MA007) Section 4.6, which
Identifies tasks that may create a potential fire hazard;
Contains specific procedures for high risk activities;
Details fire prevention measures for the site, including control of fuel;
Establishes measures for response to and control of a fire on site, including
firefighting and emergency notification procedures; and
Lists firefighting equipment such as extinguishers, blankets and water pumps to be
available on site.
Ignition sources associated with the construction phase are limited to use of machinery,
vehicles and fuels. All vehicles and machinery will be kept in good working order to
126 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
minimise the potential for fires on site. Any flammable materials required during the
construction phase will be limited in quantity and will be stored in bunded facilities as
discussed in Sections 4.7.
4.14.4 Operational Impacts and Mitigation
Effects
The design report in Appendix N includes an assessment of ‘Consequence Category’
required by the ACDC based on the ANCOLD Guidelines.
D Dam has been assessed as ‘High B’ with the assessment sheets presented in
Appendix B of the design report.
The dam failure would cause a potential tailings slide of an estimated 6 Mm3 into Ring
River and potentially creating a temporary blockage of Lake Pieman with a mound of
tailings approximately 10 m above lake level. This could cause significant damage to the
environment and clean-up of acid producing tailings would be difficult. The highest
damage and loss severity level is "Catastrophic" due to total loss of confidence of
continuing credibility, community reaction and political implications if the dam had a
catastrophic failure through the main embankment.
The failure could result in a flood wave travelling both upstream and downstream and a
rise in lake level due to the displacement of water.
The lake level rise would be limited on the downstream section of the lake and unlikely to
cause significant impact at Reece Dam (30 km downstream of D Dam) and the residential
area in Rosebery located 50 m above the lake (8 km upstream of the point where any
failure of D Dam would affect Lake Pieman). However, the lake is known for recreational
activities such as kayaking, so PAR is assessed as "1-10". Thus, a Consequence
Category of "High B" is assigned to D Dam Main Embankment.
Fire Vulnerability
The operation of D Dam poses little fire risk as there are no significant ignition or fuel
sources associated with the Dam. External fire is considered to pose a very low risk to the
operation of D Dam as all structures will be of concrete construction and the
embankments will comprise bare rock fill and clay.
Mitigation
Stability is the paramount criterion for design of D Dam. How D Dam and its components
have been designed to maintain long term stability is described in Appendix P.
Fire
BMT JV have prepared fire prevention and control plans for their existing operations, in
consultation with the authorities. These plans rely on support from local fire authorities
and State Emergency Services and are regularly reviewed and updated. The new TSF
will be included in these fire plans.
4.14.5 Monitoring
On-going dam surveillance is integral in maintaining a safe and structurally sound TSF.
BMT JV currently have a surveillance program in place for A, B and C Dam, which will be upgraded to include D Dam. Dam safety inspections will be undertaken in accordance with (and as defined in) ANCOLD (2003) and will include:
Daily to “Routine Visual” inspections by operational personnel;
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 127
Annual “Intermediate” inspections by the Dam Engineer; and
On first filling then five yearly “Comprehensive” inspections led by the Dam
Engineer.
Monitoring of various parameters is required to determine trends in structural
performance of the Dam and will include a combination of:
Rainfall;
Storage Level;
Seepage;
Pore Pressure;
Surface Movement;
Internal Movement; and
Post-Tensioning.
4.14.6 Management commitments
Commitment 41 The contractor will be required to produce a HSMP before the start of construction.
Commitment 42 Fire Prevention and Control Plans will be updated to take D Dam construction and operation into account.
128 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
4.15 Infrastructure and Off-site Ancillary Facilities
4.15.1 Legislative, Policy and Performance Requirements
All accesses, works and activities affecting the surrounding road ways are required to
comply with the relevant Austroad Guidelines, Council regulations and relevant Australian
Standards including AS 1742.3.
4.15.2 Construction Impacts and Mitigation
Effects
Movements of construction materials from the borrow areas will be within the Renison
Lease and will not use public roads. There will be a negligible increase to road traffic
associated with the construction of the dam as all heavy machinery will be stored onsite
for the duration of construction.
There will be minimal impacts to the local power supply during D Dam construction as
any construction power demand will be supplied by mobile generators.
Relatively small amounts of water will required for construction. These will be sourced
from decant ponds of existing TSFs or from Renison’s water supply. Construction
activities are not expected to affect water supply infrastructure.
Mitigation
Vehicles will be cleaned thoroughly before leaving the site;
Speed will be limited to 40 km/h on internal roads and traffic limited to daylight
hours.
A controller will be appointed to coordinate vehicle movements by radio.
4.15.3 Operational Impacts and Mitigation
Traffic Impacts
The operational traffic impacts of D Dam will be negligible. The only vehicular movements
created will be between the Processing Plant and D Dam, associated with routine
maintenance. This will have no impact on public roadways and will be generally
unchanged from current movements associated with the existing TSFs.
Impacts on Power Supply
The dam itself does not require a power supply so impact on power supply is not
anticipated.
Impacts on Water Supply Infrastructure
Water input to D Dam is via tailings discharge and natural rainfall. Stand-alone freshwater
input is not required for day-to-day operation. The only requirement for freshwater input
would occur in the event of a premature / emergency closure. In this instance water would
be drawn from the mine and from Argent Dam (the current dedicated Renison water
source) utilising existing infrastructure. This is discussed further in Section 8.
The maximum quantity of fresh water required to cover the TSF to an optimal depth of 2
m, assuming no rainfall or input of process water, is in the order of 1,500 ML.
Approximately 2,463 ML per year of groundwater is currently pumped from the mine
during routine operations. Upon closure, given this quantity of surplus groundwater,
Argent Dam’s capacity of approximately 318 ML and the high rainfall of the area (in
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 129
excess of 2,000 mm per year), this quantity is not anticipated to pose a significant burden
on the water supply of Argent Dam.
4.16 Cumulative and Interactive Effects
Cumulative and interactive effects can be defined as arising from the presence of more
than one future development including the Project; and which are different in scale and/
or nature to those originating from each project alone.
No other developments are known to be proposed in the area which could contribute to
cumulative effects.
Existing operational activities at the mine will continue and hence have formed the
baseline for the assessment undertaken in Section 4, and therefore no cumulative effects
are expected.
Cumulative effects as they relate to cumulative effects from existing operations (e.g.
aquatic impacts associated from proposed and existing drains and seeps) are addressed
under the relevant discipline headings of this DPEMP.
130 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
5. EPBC Assessment 5.1 Background
The proposal was referred to the Commonwealth Minister (project reference
EPBC2012/6448) in July 2012. The project was determined to be a Controlled Action and
therefore approval is required from the Commonwealth Department of Environment, as it
has the potential to significantly impact Matters of National Environmental Significance
(MNES) protected under the EPBC Act.
5.2 General Information
Sections 1 and 2 of this DPEMP list general information relating to the Controlled Action
as required by Schedule 4 of the EPBC Regulations 2000.
5.3 Relevant Impacts
This section summarises the impacts on MNES with reference to description of the
ecological values and impacts described in Section 4 and Appendix I.
Table 5-1 Presents a summary of the assessment of significance of predicted impacts on
MNES, noting that the detailed assessment of ecological values and impacts is provided
in the sections noted above.
5.3.1 World Heritage Properties
No impact on world heritage values or world heritage properties is expected.
5.3.2 National Heritage Places
No impact on National heritage values or National Heritage places is expected.
5.3.3 Wetlands of International Importance (declared Ramsar wetlands)
No impact on Ramsar wetlands is expected.
5.3.4 Commonwealth Marine Area
No impact on Commonwealth marine areas is expected.
5.3.5 Commonwealth Land
There is no Commonwealth land within the proposal area or likely to be impacted upon by
the proposal.
5.3.6 The Great Barrier Reef Marine Park
No impact on the Great Barrier Reef Marine Park expected.
5.3.7 Listed Threatened Species and Ecological Communities
Receptors Affected
The project was assessed via methods described in Section 3.4.5 and Appendix I and
has the potential to affect the following EPBC listed threatened fauna species:
Spotted-tailed quoll;
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 131
Tasmanian devil;
Tasmanian masked owl
white bellied sea eagle
wedge-tailed eagle; and
azure kingfisher.
Impacts
Table 5-1 provides a summary of the predicted impacts and proposed mitigation for the
MNES species listed above. Full details of these measures are contained in Section 4.3
and Appendix I.
A number of the measures will be implemented through the construction and operational
environmental management frameworks defined in Section 6.2.
This assessment of impact (as summarised in Table 5-1) considers the direct and indirect
impacts (e.g. fauna road kill) of the TSF project in the context of the existing local
developments and impacts (i.e. existing mining operations and local road traffic). There
are no other cumulative impact assessments deemed necessary as there are no other
known developments proposed for the site or immediate surrounds.
5.4 Proposed Safeguards and Mitigation Measures
5.4.1 Mitigation Measures
Mitigation for predicted impacts on MNES are summarised in Table 5-1. Measures to
mitigate impacts on ecological receptors are described in Section 4 and Appendix I.
5.4.2 Biodiversity Offsets
Potential impacts, mitigation measures and residual impacts arising from the project are
summarised in Table 5-1. The project would result in direct residual impacts on native
biota, including the long term removal of 54.5 ha of native vegetation that may provide
foraging, nesting and/or denning habitat for a number of threatened fauna species.
Approximately 18 ha of the 54.5 ha of cleared native vegetation will be rehabilitated to
previous vegetation communities following closure of the borrow areas. Approximately
two thirds of the tailings surface will also be vegetated following closure.
Environmental management measures are proposed to mitigate against secondary
impacts on biodiversity values, and restrict impacts to those residual impacts.
Assessments of significance of residual impacts on the local populations of potentially
affected threatened fauna have been prepared in accordance with the Australian Government’s Significant Impact Guidelines (DOTE 2013). These are described in full in
Appendix G of the Ecological Assessment Report in Appendix I.
The outcome of these assessments is that the Project is not expected to result in
significant impacts on any threatened species or other MNES, and so biodiversity offsets
should not be required under the Commonwealth Environment Protection and Biodiversity
Conservation Act 1999: Environmental Offsets Policy and associated Offsets Assessment
Guide (DSEWPaC 2012).
132 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Table 5-1 Potential Impacts on EPBC Listed Threatened Species
Receptor Potential Impact Description Likely Impact Significance
Mitigation Likely Residual Impact
Tasmanian devil Disturbance of active dens during site clearance.
Potentially significant (if active dens disturbed)
Pre-clearance visual survey and implementation of a Devil Den Decommissioning Plan if active dens identified. Local clearance to occur outside breeding season if active dens identified.
Not significant (pre-clearance surveys will identify active dens, so impacts can be avoided)
Clearance of foraging and potential denning habitat in a DFTD free area.
Not significant
No specific mitigation proposed for habitat loss, measures as proposed for native vegetation community loss. Rehabilitation of borrow areas.
Permanent removal of c. 36.5 ha of foraging and potential denning habitat
Death or injury from construction traffic. Vehicle movements will be limited to daytime hours and 40 km/h. To prevent attracting devils to the road, daily inspection and removal of any carcasses on the haul road (disposed of to landfill) will be undertaken during construction and operational phases to minimise potential for predator road kill.
Spotted-tailed quoll
Clearance of foraging and potential denning habitat.
Not significant
No specific mitigation proposed for habitat loss, measures as proposed for native vegetation community loss. Rehabilitation of borrow areas.
Permanent removal of c. 36.5 ha of foraging and potential denning habitat
Death or injury from construction traffic. Vehicle movements will be limited to daytime hours and 40 km/h. To prevent attracting quolls to the road, daily inspection and removal of any carcasses on the haul road (disposed of to landfill) will be undertaken during construction and operational phases to minimise potential for predator road kill.
Tasmanian azure kingfisher
Site clearance (loss of foraging habitat only). No clearance is proposed within breeding / nesting habitat, which is abundant locally outside of the project footprint. Low potential for impact to downstream water quality affecting species (such as azure kingfisher) reliant on downstream environment for water and food.
Not significant
None proposed. Mitigation measures presented in Sections 4.1 (Surface Water) and 4.2 (Groundwater) to protect downstream water quality will also protect terrestrial fauna utilising downstream environment.
Permanent removal of c. 9 ha of foraging habitat.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 133
Wedge-tailed eagle
No nests identified in the footprint. Site clearance (loss of habitat) Noise and/or visual disturbance.
Not significant
Clearance outside breeding season if possible. Where this is not possible pre-clearance foot based survey of areas mapped as ‘medium priority’ nesting habitat to check for eagles which may have recently colonised the site. If suspected nests are identified, exclusion of 500m absolute and 1000m line of site to be applied during the breeding season.
Permanent removal of c. 36.5 ha of foraging habitat
Tasmanian masked owl
No masked owl identified within project footprint Site clearance (loss of habitat).
Not significant
Clearance outside breeding season or pre-clearance survey and exclusion of clearance of tree until breeding complete.
Permanent removal of c. 5.2 ha of mature eucalypt communities
Australian grayling
None – species unlikely to be present on site. Not significant
None proposed None
Listed migratory species
Site clearance (loss of habitat). Low potential for impact to downstream water quality affecting species (such as white bellied sea eagle) reliant on downstream environment for water and food.
Not significant
Mitigation measures presented in Sections 4.1 (Surface Water) and 4.2 (Groundwater) to protect downstream water quality will also protect terrestrial fauna utilising downstream environment.
Permanent removal of <36.5 ha potential habitat
134 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
5.4.3 Other Approvals and Conditions
Environmental approval is sought from the Tasmanian EPA Board under the EMPC Act
as summarised in Section 1.7.
Planning approval for D Dam will be sought from the West Coast Council under the
LUPAA according to the policy framework set out in the West Coast Council Interim
Planning Scheme 2013. The relevant planning policies and performance of D Dam
against those is described in Appendix B.
The proposed management and monitoring regime for D Dam are set out in Sections 6
and 7. Any requirements for monitoring, enforcement and review will be conditioned
through a Development Approval granted under the LUPA Act and the Operating license
and EMPC Act.
5.5 Environmental Record of Proponent
Section 1.4 of this DPEMP contains a statement regarding the environmental record of
the proposal.
5.6 Information Sources
The up-to-dateness, reliability and uncertainties associated with information used in this
DPEMP are discussed alongside the data throughout the document.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 135
6. Environmental Management Systems 6.1 Management System Description
BMT JV is continually developing its risk-based management system based on the
requirements of the international management system standard, ISO 14001.
Managing of environmental impacts is covered by the BMT JV Environmental Policy
Statement (see Appendix Q) and more widely by the Renison Operation Environmental
Management Plan (BMT JV 2013). These state commitment to environmental
performance and continuous improvement and is endorsed by top-level management.
6.2 Construction Environmental Management Plan (CEMP)
A CEMP will be prepared and implemented prior to the start of construction. This will
establish a management system to address the construction impacts assessed in Section
4.
This section provides a framework for the CEMP to which more detail will be added
during detailed design and construction planning.
The Contractor will appoint an experienced environmental representative, with
responsibility for ensuring that the needs of the CEMP are met.
6.2.1 Policy
BMT JV will ultimately be responsible for activities by appointed contractors during the
Construction of D Dam. Consequently the CEMP will be underpinned by the BMT JV
Environmental Policy Statement April 2010 (see Appendix Q).
6.2.2 Aspects and Impacts
Based on the assessment in the DPEMP, the CEMP will provide a tabular summary of
the environmental aspects and impacts of the construction work.
6.2.3 Objectives and Targets
Objectives and targets will be derived from the performance targets described in each
sub section of Section 4.
6.2.4 Management Structure, Roles and Responsibilities
Figure 6-1 provides an outline organisation structure. Responsibility for the environmental
activities on site will lie ultimately with the BMT JV general manager, however the BMT
JV Processing Manager will be directly responsible for the CEMP. The HSE Manager will
provide technical support to the Processing Manager both directly and indirectly during
the project via the BMTJV Environmental Coordinator.
136 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Figure 6-1 CEMP Organisation Chart
6.2.5 Induction and Training
The CEMP will set out a program of training. All site staff will undergo a basic
environmental induction to explain:
The site, the project, sensitive features, risks and impacts;
Their roles and responsibilities within the CEMP;
Reporting lines;
Specific procedures;
Environmental issues and features.
Specific training may be given to site staff on ad hoc issues. This may take the form of
toolbox talks organised by the Contractor’s site manager.
6.2.6 Communication
All communication will be coordinated through the BMT JV Project Manager. Regular
meetings will be held between the BMT JV HSE Manager and the Contractor’s Site and
Environment Managers. The contractor will prepare a regular report on performance
against the CEMP.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 137
6.2.7 Documentation
All polices and plans included with the CEMP will be approved by the BMT JV HSE
Manager and the BMT JV General Manager. A procedure for the control of contractor and
BMT JV documentation will be included with the CEMP.
6.2.8 Environmental Control Procedures
The CEMP will define specific procedures detailing the implementation of Construction
mitigation identified in Section 4.
6.2.9 Site Access and Egress
The CEMP will contain a plan to manage entry and exit from the site and to ensure that
works do not encroach beyond the defined site boundary, which will include:
Site plan clearly delineating the project footprint and significant features (if any);
Clearly identifiable and manageable site entry and exit location(s);
Clearly defined boundary markers to define the site boundary.
6.2.10 Waste Management Plan
The Contractor will have responsibility for operating a Waste Management Plan, the
framework for which is as follows:
Volume and type of construction waste will be recorded and provided to BMT JV in
a monthly report;
Storage facilities will be clearly identified and their waste type signed;
Offsite disposal locations will be identified in advance and all transfer paperwork
retained;
All staff will receive training in waste management measures as part of site
induction; and
BMT JV will audit the contractor’s waste management plan and raise non-
conformances and corrective actions as necessary.
6.2.11 Environmental Incident Control Plan
An environmental incident is defined as:
A pollution incident;
A third party complaint;
Unplanned damage to an ecological species or community; or
Unexpected discovery of a threatened or listed ecological or heritage feature.
Roles and responsibilities
The contractor will appoint staff with responsibility for implementing preventative
measures, ensuring readiness and coordinating response to an environmental incident.
BMT will retain ultimate responsibility for activities during D Dam construction and will
review and approve contractor environmental incident control plan and audit its
implementation.
138 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Pollutant inventory
A register of pollutants used on the Project will be maintained (see Section 4.1.3)
Response Measures
Any activity resulting in an incident will cease until the incident has ceased.
Liquid spills will be contained using a spill kit.
All spills will be cleaned up and disposed of as hazardous waste.
All incidents will be investigated by BMT JV and corrective actions raised where
necessary.
Notification
All incidents and near misses will be reported by the contractor to BMT JV. Serious
incidents will be reported to the EPA in same manner as incidents resulting from existing
operations.
Equipment
The team will be suitably equipped to respond to an environmental incident; including spill
kits (see Section 4.1.3)
Communication and Training
Site induction for staff will include instruction related to environmental incident control
plan.
6.3 Operational Environmental Management Plan
The current BMT JV Environmental Management Plan (2013) describes the
environmental management practice of the entire Renison operation (including annual
environmental reporting and EMP review).
Operational management of D Dam will fall under the existing EMP framework (in the
BMT JV EMP 2013, available from BMT on request), subject to amendments
incorporating commitments listed in Section 4 and any specific Permit conditions imposed
with the DA.
BMT JV will update the EMP to include D Dam upon approval from Council, the EPA and
the Commonwealth.
6.4 Management Commitments
Commitment 43 A CEMP, based on the framework described in Section 6.2 will be prepared and implemented prior to the start of construction.
Commitment 44 The Contractor will appoint an experienced environmental representative, with responsibility for ensuring that the needs of the CEMP are met.
Commitment 45 Existing site Operational Environmental Management regime will be updated to include operation of D Dam.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 139
7. Monitoring and Review 7.1 Pre clearance surveys
As described in Section 4.3.3 pre-clearance surveys will be undertaken for the following
species, depending on the season when clearance starts:
Tasmanian devil visual and spotted tailed quoll
Tasmanian masked owl
Wedge tailed eagle and white bellied sea eagle
Azure kingfishers
Grey goshawk
7.2 Construction Surveillance
During construction, the Contractor will be required to conduct surveillance for impacts.
This will include:
Daily visual inspection for dust at earthworks;
Continuous inspection of vehicles for weeds and other pathogens at site entry;
Daily visual inspection for leaks and spills of hazardous materials at storage and
fuelling areas and where plant are operating;
Continuous monitoring of grouting rates at pumps during grouting;
Daily visual monitoring of site runoff for turbidity at points draining active
earthworks and exposed soils;
Continuous surveillance for unanticipated heritage finds during excavation and
clearance;
Statutory noise monitoring during blasting, if required;
Monitoring of construction waste; and
Health and Safety monitoring.
Identification of environmental non-conformances during construction will include ongoing
surveillance during inspections by BMT JV Environmental professionals.
7.3 Operational Monitoring
A program of monitoring (summarised in 7) will be established for the pre-commissioning,
construction and operational phases of the project.
Specific details of the monitoring programs for each topic are covered in the relevant
parts of Section 4.
As far as practicable this will be incorporated into the existing monitoring program
described in the Renison Operation EMP (BMT JV, 2013).
This section covers construction and operational monitoring. Section 8 describes post
closure monitoring.
140 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Table 7-1 Summary of Monitoring Programme
Topic Description Location Frequency Relevant
Section
Decant pond
level
monitoring
Automated piezometer
gauging system linked
to process plant
In decant
pond
Continuous 2.2.7
Tailings
Geochemistry
Continuation of
existing BMT JV,
2013)
Plant Daily 2.7.1
Tailings
seepage
Piezometer arrays to
manage embankment
pore pressure.
Within D1, D2
and D4
embankments
Continuous 2.2.6
Routine seepage
monitoring at V notch
weirs.
S2 and S3 Fortnightly 2.2.6
PAF cell
Monitoring
Piezometer to monitor
water level and
oxygen sensors at top
and bottom of cell
Within cell Continuous 2.4.7
Discharges to
Surface
Water
In situ physical
parameters, major
anions, cations and
metals
TD, S2 and
S3, S4 and C
and B Dam
seepage
interceptors
and A Dam
(pre-TSF fill)
Fortnightly
/ monthly
4.1.5
Ambient
Surface
Water
Monitoring
In situ physical
parameters, major
anions, cations and
metals
Existing
monitoring
points and
new points
RAB and
RBB
Monthly 4.1.5
Groundwater
levels
Groundwater level
meter
GW5, GW6,
GW9, GW10,
GW11, GW12
Hourly 4.2.5
Embankment
pore pressure
Vibrating wire
piezometers
D1, D2 and
D4
embankment
continuous 2.2.6
Groundwater
chemistry
In situ physical
parameters, major
anions, cations and
metals
GW5, GW6,
GW9, GW10,
GW11, GW12
Quarterly
(lab tests)
4.2.5
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 141
Topic Description Location Frequency Relevant
Section
Pest fauna
species
Monitoring and
recording of feral cats
and dogs
Clearance
footprint
Ongoing 4.3.5
Aquatic
ecology
Continuation of
existing AUSRIVAS
Invertebrate survey
programme
ARGENT
001,002,003,
RING 001,
0002
Biannually 4.3.5
Dust Visual surveillance for
blowing dust
TSF Daily 4.4.5
Dam safety Routine visual
inspections by
operational personnel
TSF Daily 4.14.5
Intermediate
inspections by Dam
Engineer
Annually 4.14.5
Comprehensive
inspections by Dam
Engineer
First filling
and 5
years after
4.14.5
7.4 Post Commissioning Review
A review of the DPEMP impacts and commitments will be undertaken as part of the
annual review of operations and reported in the Annual Environmental Report, the
September following the final commissioning of the Dam. All monitoring results will be
addressed as per EPN 7092/2.
7.5 Management Commitments
Commitment 46 The monitoring program described in Section 7.2 will be implemented during the construction of D Dam.
Commitment 47 Operational monitoring measures in Section 7.3 will be incorporated into the existing monitoring regime for Renison.
Commitment 48 A Post Commissioning Review will be undertaken the first September after commissioning.
142 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
8. Preliminary Decommissioning and Rehabilitation Plan A detailed decommissioning and rehabilitation plan (DRP) will be prepared within 30 days
of notifying the Director of any decision that is likely to give rise to the temporary or
permanent cessation of activity, as outlined in the EPN 7092/2.
Closure of D Dam will be incorporated into the next review of the Renison Site Closure
Plan.
Based on the production rate assumed in Section 2.2.1 the estimated year of closure for
D Dam, as described in Section 2.2 is 2032. This will be subject to a range of operational
factors.
Closure planning will be subject to regular review during D Dam’s operational life.
8.1 TSF Closure method
8.1.1 Key Principles
The key principles for the successful closure of a tailings dam are:
Long term stabilisation of physical, chemical, ecological and social conditions of the
tailings dam to minimize ongoing degradation.
The closed facility should not require ongoing maintenance and expenditure other
than normally required for similar land use.
In order to achieve the above, D Dam has been designed to focus on two keys areas:
Mitigation of AMD through tailings management; and
Develop a long term stable structure by minimising the extent to which the
embankments are maintained as water retaining structures.
8.1.2 Tailings Cover on Closure
The proposed final closure scenario for D Dam is a full water cover over the high sulphide
tailings (HST) and a vegetation cover over the low sulphide tailings (LST).
After the first three years of operation this method will also be applicable as emergency
closure method in the event of premature unplanned closure. In advance of this, in the
unlikely case that an unplanned closure takes place in the first three years of operation a
full water cover of 2 m will be possible within the water retaining embankment.
D Dam has been designed to minimise the likelihood of AMD by managing the deposition
of high sulphide tailings (HST) so that it remains below the LST height and will be
inundated on closure, whether this takes place at the ultimate level of 180 m AHD or after
a premature closure due to an unplanned end to operations.
As described in Section 2.5.2, after the first 2 years of operation HST deposition will be
limited to the southern side of the storage at a lower level than the LST, which, on closure
will maintain a permanent 1.2 m water cover for the HST.
Given the relatively small area of the overlying pond and limited fetch for waves to form,
1.2 m is considered sufficient depth to prevent stirring up of HST.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 143
The LST beaches (which do not pose an AMD risk) would be capped by a soil/ water
cover. This is more desirable than totally flooding the TSF because:
It will allow the colonisation of the TSF wetland flora and fauna, creating habitat in
the longer term, rather than creating a large sterile deep-water pond;
It reduces the risks of maintaining water permanently against the dam
embankment, lowering the phreatic surface and providing a more stable landform;
and
It increases the storage capacity in D Dam without further raising the crest level.
D Dam is designed to hold water and therefore uses the downstream construction
method (as described in Section 2.5.2). This downstream construction method also
allows for premature closure in all scenarios (i.e. even if closure were to occur prior to
submersion of the HST after the first two years) by flooding the TSF.
8.1.3 Long Term PAF Cell Closure
As discussed in Section 2.4.5, the clay barrier, depth of cover and saturation at closure
will limit oxygen diffusion sufficiently to prevent acid generation of the PAF waste rock
cell, in the long term.
If an unplanned closure took place before the PAF cell cover is deep enough to provide
the necessary degree of saturation, a water cover will be maintained above the PAF cell
to ensure no oxygen ingress.
8.1.4 Long Term Stability
The D Dam embankment and closure method have been chosen for long term stability.
The D Dam design includes preliminary stability analysis on the critical sections of the
completed TSF to review the conceptual geometries of the embankment. These included
Limit Equilibrium slope stability analysis under static loading and an estimate of the
settlement of the embankment crest induced by selected earthquake events. The studies
concluded that the dam would be stable under the design loading listed in ANCOLD
Guidelines. Embankment stability analysis is described in detail in Appendix O.
For long term stability, the embankment should not rely on aspects of the embankment
that may deteriorate over time. In particular, in the very long term filters may become
partially or fully blocked, potentially resulting in piping failure. The filters are needed for
the dam to remain a water retaining structure. To address this risk, the deposition within
the TSF (as described in Section 2.5.2) will form a LST tailings beach against the
embankment, reducing the risk of a piping failure by:
Reducing the hydraulic gradient through the embankment and foundations to
minimise the risk of internal erosion; and
Reducing the opportunity for potential seepage paths to propagate by removing
available water at the embankment.
8.1.5 Final Geometry
The final crest levels above sea level on the Dams are shown below in order of
decreasing height:
C Dam 194.5 m;
A Dam 192 m;
B Dam 191 m;
144 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
D Dam 180 m.
D Dam has been designed with sufficient batter slopes to remain stable during operations
and after final filling and closure of the dam. Small vegetation that would not inhibit dam
safety or inspection visibility would be encouraged on the dam embankment.
8.1.6 Closure drainage
It is expected that upon final closure of the four TSFs a water circuit will be created,
starting from C Dam and flowing through A Dam, B Dam then to D Dam. D Dam will
discharge at a single point through the spillway to the Ring River. This will provide the
benefits of maximising the catchment ensuring the water covers of the dams are kept
from drying out and increasing the retention time of any waters entering the system.
8.1.7 Seepage
Post closure seepage will be limited by:
The low permeability core to minimise seepage;
The grout curtains;
The low permeability liners;
The low tailings permeability; and
The reduced hydraulic gradient from having a LST beaches.
Some seepage will still occur (as discussed in Section 2.7.2) but AMD seepage will be
prevented by preventing acid generation as described in 2.5.2.
8.2 Rehabilitation
8.2.1 Embankment
Trees expected to grow no more than one metre in height would be permitted on the D
Dam embankments and the embankment would be cleared regularly as part of post
closure maintenance allowing inspection access.
If a vegetated LST / water cover over HST method is employed for closure this would
provide opportunity for a wetland area in the zone between the pond /water cover and
natural ground /pond and additional vegetation on the beaches close to the
embankments. Large/medium trees would be discouraged from establishing in the cover,
as they will eventually die/blow over with root bulb exposing the underlying tailings.
However a planting regime could include small to medium shrubs, progressing to smaller
wetland species towards the pond itself. When decommissioned A and B Dams were successfully colonised by juncus sp. and other species.
As part of rehabilitation, declared and high priority weeds in disturbed areas will be
removed and disposed of. The Closure Plan will include a weed management plan for the
closure and rehabilitation of D Dam based on the Weed Management Plan in Appendix I.
8.2.2 Borrow Areas
As discussed in Section 2.3, the C Dam and West Pieman Borrow Areas will be required
to construct the D Dam embankment to its final level and will need to remain open till this
time.
Once no longer in use, the borrow areas will be rehabilitated. This will entail:
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 145
Re-contouring of benches to a maximum gradient of 1 in 3 to minimise erosion
potential.
Stockpiles and other mounds will be levelled.
Installation of closure erosion control by adapting the existing erosion control
measures (sediment ponds, cut off drains etc.) and by installing new measures,
such as spillways as necessary.
Spreading of stored topsoil and /or mulch from stockpiled vegetation waste from
clearance.
Contour ripping to aid seed germination and water infiltration.
Revegetation will aim to recreate natural vegetation communities and therefore the
site will be left to revegetate naturally by wind blows seeds. Where monitoring
shows this not to be successful, seed mix purchased or nursery grown plants will
be used.
Weed management during the revegetation of borrow areas will be as outlined in
the Weed Management Plan in Appendix I
Behaviour of existing cleared areas elsewhere on the Renison site suggests that
revegetation will be relatively straightforward, since ample evidence already exists of
pioneer colonies establishing themselves in these areas.
8.2.3 Other Clearances
Test pits / excavations will be battered back or backfilled to make safe. Tracks will be
retained for the D Dam construction phase and access for future use.
8.3 Post Closure Monitoring and Maintenance
Table 8-1 summarises the key aspects of the anticipated the post-closure monitoring. Full
details will be provided in a decommissioning and rehabilitation plan which will be issued
for approval by the EPA.
Table 8-1 Summary of Post Closure Monitoring
Discipline Frequency Scope
Surface water Monthly for 2
years
6 monthly for a
further 3 years
Monitoring locations and parameters
as listed in Section 4.1.5
Groundwater 6 monthly for 5
years
Monitoring locations and parameters
as listed in Section 4.2.5.
Ecology, vegetation and
weeds
Annually until a
stable post
closure cover has
been attained (as
assessed by a
qualified
ecologist).
Success of rehabilitation of
vegetation communities and habitat
Extent of any weed infestations
146 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
8.4 Stakeholder Consultation
Prior to closure BMT JV will consult key stakeholders to discuss closure, rehabilitation
and long term monitoring, anticipated to be the following:
Local council;
HydroTasmania;
Downstream stakeholders;
Parks and Wildlife Service;
Local community;
Mineral resources Tasmania; and
EPA.
The Leading Practice Sustainable Development Program for the Mining Industry handbooks relating to Tailings Management, Mine Closure and Completion, and Mine
Rehabilitation will be referred to when preparing Closure, Decommissioning and
Rehabilitation plans.
8.5 Management Commitments
Commitment 49 The final closure of D Dam will be a full water cover over the high sulphide tailings (HST) and vegetation cover over the low sulphide tailings (LST).
Commitment 50 If unplanned closure takes place in the first three years of operation a full water cover of 2 m within the water retaining embankment will be created.
Commitment 51 A detailed decommissioning and rehabilitation plan (DRP) including details of post-closure monitoring and maintenance will be prepared prior to closure and within 30 days of notifying the Director of planned closure.
Commitment 52 Following closure the borrow areas and associated haul road will be rehabilitated to native forest
Commitment 53 The Closure Plan will include a weed management plan for the closure and rehabilitation of D Dam.
Commitment 54 A post closure drainage regime will be established.
Commitment 55 Prior to closure BMT JV will consult key stakeholders.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 147
9. Commitments The following is a consolidated list of commitments included within this DPEMP:
Commitment 1 Measures to prevent and mitigate impacts on surface water from
releases of hazardous materials will include secure storage, careful
handling, and recording of hazardous materials as described in Section
4.1.3.
Commitment 2 An Environmental Incident Control Plan will be prepared by the
contractor based on the framework in Section 6.2.11.
Commitment 3 Measures to manage erosion and sediment described in Section
4.1.3 will be implemented though an Erosion and Sediment Control Plan
during construction.
Commitment 4 Measure to potential AMD issues associated with construction
materials will be taken as described in Section 4.1.3
Commitment 5 Cement will be carefully handled and pumping rates monitored
during grouting to prevent loss of control.
Commitment 6 Weed control in sensitive areas will be undertaken by manual
removal or targeted spot spraying with low-toxicity non-residual
herbicides.
Commitment 7 A Tailings Management Plan will be prepared prior to
commissioning of D Dam.
Commitment 8 Tailings will be placed and HST segregated to prevent oxidisation
as described in 2.5.2.
Commitment 9 Grout curtains below the main and decant embankments, a clay
lining of the decant pond and any other permeable zones will be installed
as described in Section 2.2.6.
Commitment 10 All PAF waste material will be placed below 160 m AHD to allow
inundation and saturation within two years.
Commitment 11 PAF waste rock will be dosed with sufficient lime to neutralise
existing and potential acidity until full inundation occurs.
Commitment 12 Vegetation clearance or damage outside the footprint will be
avoided by flagging, fencing and site access plans.
Commitment 13 Where possible, given the nature of the clay resource, borrow areas
used will start in existing cleared, disturbed areas and end at the least
disturbed areas, so that any reductions in material demand will lead to
reductions in clearance of the highest quality habitats.
Commitment 14 Storage of materials and/or machinery will utilise existing cleared
areas.
Commitment 15 Haul road from the borrow areas will be created by widening
existing survey track.
Commitment 16 A weed control and hygiene plan will be implemented during the
construction and operational phases.
148 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Commitment 17 Construction site vehicle movements will be limited to daytime
hours and speeds of less than 40 km/h.
Commitment 18 If possible, vegetation clearance will be undertaken in April, May or
June which has the lowest potential for breeding of threatened species.
Commitment 19 Before any clearance a devil and quoll visual den survey will be
undertaken to identify any active use of the key potential denning
features previously identified.
Commitment 20 Should an active den be found prior to clearance a Devil Den
Decommissioning Plan will be implemented and relevant permits sought.
Commitment 21 During both construction and operation, the site roads will be
checked daily for presence of dead animals and any carcasses found
removed immediately and disposed of at the local landfill.
Commitment 22 No pet dogs will be kept on the construction site.
Commitment 23 Woody debris generated will be used to create potential denning
habitat around the clearance boundary.
Commitment 24 Pre clearance surveys for Tasmanian masked owl nesting will be
undertaken before any clearance between September and the end of
March. If present, no clearance will start in that area until after the
breeding season or the nest is confirmed vacated.
Commitment 25 Before any clearance from September to February inclusive
surveys for breeding azure kingfishers will be undertaken. If present, no
clearance will start in that area until after the breeding season or the nest
is confirmed vacated.
Commitment 26 Before any clearance from July to January inclusive a foot based
survey for eagles nest will be undertaken within areas mapped as
medium priority nesting habitat. If present, no clearance will start in that
area (500 m absolute and 1000 m line of sight) until after the breeding
season or the nest is confirmed vacated.
Commitment 27 Before any clearance from September to February inclusive
surveys for breeding grey goshawk will be undertaken. If present, no
clearance will start in that area until after the breeding season or the nest
is confirmed vacated.
Commitment 28 Existing feral animal trapping executed under the BMT
Environmental Management Plan will continue during the construction
and operation of D Dam.
Commitment 29 PWS will be notified of wildlife injured during construction. Where a
local wildlife carer is available for a given species, the animal will be
taken for treatment and rehabilitation. Injured wildlife will be treated
according to the relevant guidance from PWS.
Commitment 30 Dust during construction will be managed by limiting vehicle speeds
(40 km/hr limit within the dam site), vehicle wash down prior to leaving
the site; and damping of roads and covering of vehicles when daily visual
monitoring indicates visible dust plumes.
Commitment 31 All construction vehicles and plant will be maintained to keep
emissions to a minimum.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 149
Commitment 32 Permits will be sought for any blasting required.
Commitment 33 Vegetation waste will be stored for later use.
Commitment 34 Subject to permitting, the useable timber will be extracted and the
remaining vegetation will be cleared using bulldozers to the edge of site.
Commitment 35 No burning of cleared vegetation is proposed.
Commitment 36 Where practical, topsoil extracted from the embankment footprint
will be segregated for storage and reuse.
Commitment 37 Construction waste (not including soil and vegetation) will be stored
securely to prevent escape and removed from site regularly.
Commitment 38 A register of any dangerous goods used as part of the construction
will be prepared.
Commitment 39 Monitoring will be undertaken by the construction contractor during
all ground disturbing construction works, and if any sites are identified
works will cease.
Commitment 40 If a suspected heritage feature is discovered, work will cease, AHT
or HT will be notified and arrangements made for identification of the
feature.
Commitment 41 The contractor will be required to produce a HSMP before the start
of construction.
Commitment 42 Fire Prevention and Control Plans will be updated to take D Dam
construction and operation into account.
Commitment 43 A CEMP, based on the framework described in Section 6.2 will be
prepared and implemented prior to the start of construction.
Commitment 44 The Contractor will appoint an experienced environmental
representative, with responsibility for ensuring that the needs of the
CEMP are met.
Commitment 45 Existing site Operational Environmental Management regime will be
updated to include operation of D Dam.
Commitment 46 The monitoring program described in Section 7.2 will be
implemented during the construction of D Dam.
Commitment 47 Operational monitoring measures in Section 7.3 will be incorporated
into the existing monitoring regime for Renison.
Commitment 48 A Post Commissioning Review will be undertaken the first
September after commissioning.
Commitment 49 The final closure of D Dam will be a full water cover over the high
sulphide tailings (HST) and vegetation cover over the low sulphide
tailings (LST).
Commitment 50 If unplanned closure takes place in the first three years of operation
a full water cover of 2 m within the water retaining embankment will be
created.
Commitment 51 A detailed decommissioning and rehabilitation plan (DRP) including
details of post-closure monitoring and maintenance will be prepared prior
to closure and within 30 days of notifying the Director of planned closure.
150 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
Commitment 52 Following closure the borrow areas and associated haul road will be
rehabilitated to native forest
Commitment 53 The Closure Plan will include a weed management plan for the
closure and rehabilitation of D Dam.
Commitment 54 A post closure drainage regime will be established.
Commitment 55 Prior to closure BMT JV will consult key stakeholders.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 151
10. Conclusion D Dam is the fourth in a series of tailings storage facilities required for the ongoing
operation of the Renison Bell Tin Mine. It will incorporate a cell to dispose of PAF waste
rock and ameliorate existing seepage issues. The proposed TSF and management
approach have been carefully considered to minimise risk of AMD.
The key environmental impacts associated with the dam include clearance of native
vegetation, limited noise and air emissions, limited visual intrusion, potential impacts to
geomorphological features, seepage to the groundwater system and surface seepage
and decant water discharged to the water bodies of Lake Pieman and the Ring River.
Section 4 outlines a range of mitigation measures aimed at minimising these impacts.
Section 5 outlines ongoing monitoring procedures required to measure the long term
success of the new dam and provide timely feedback of any potential impacts such that
these can be managed accordingly.
152 | GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878
11. References AMIRA, May 2002, ARD Test Handbook – Project P387A, Prediction and Kinetic Control
of Acid Mine Drainage.
Australian National Committee on Large Dams Inc. (ANCOLD) (2003) Guidelines on Dam
Safety Management, August 2003.
Becker J and Sainty R (2000) Cultural Heritage Survey of Proposed Dalcoath Quarry
Extension. Commissioned by Henry Laszczyk on behalf of Renison Bell Limited.
25/01/2000.
BMT JV, 2013. Renison Operation Environmental Management Plan April 2013.
Bureau of Meteorology Website,
http://www.bom.gov.au/climate/averages/tables/cw_097072_All.shtml, accessed
25/01/12.
Coffey, 2013. Hydrogeological Assessment Report For BMT JV. October 2013 Ref:
ENAUHOBA06895AA
Department of the Environment (cited as DOTE), 2013: Matters of National
Environmental Significance, Significant impact guidelines 1.1 – Environment Protection
and Biodiversity Conservation Act 1999.
Department of Infrastructure, Energy and Resources (DIER), 2012. Tasmanian
Government 2012 Submission to Nation Building 2 Program Murchison Highway
Upgrades.
DPIW 2008. CFEV assessment framework Summary. Conservation of Freshwater
Ecosystems Values Project Water Assessment Branch Water Resources Division.
Department of Primary Industries and Water
DPIWE, 1999. Quarry Code of Practice. Department of Primary Industries Water and
Environment / Department of Infrastructure Energy and Resources.
DPIPWE, 2000. Threatened Species Strategy for Tasmania 2000, Nature Conservation
Branch, Department of Primary Industries, Water and Environment
GHD, 2012. ‘C Dam Closure and Future Tailings Storage Options’ GHD memorandum,
November 2012.
INAP, 2012. Global Acid Rock Drainage Guide. Chapter 6 Prevention and Mitigation.
International Network for Acid Prevention. http://gardguide.com/index.php/Chapter_6 Last
updated June 2012.
Natural Values Atlas, https://www.naturalvaluesatlas.dpiw.tas.gov.au/pls/apex/f?p=200:1:,
accessed 12/05/08.
Resource Planning and Development Commission (2003). State of the Environment
Tasmania 2003, last modified 14 December 2006, http//www.rpdc.tas.gov.au/soer,
accessed 11 July 2008.
Rosebery Deposits and Mining Tenements 1:25,000 Map (Rosebery 3667)
Sim R and Moore M.W (1999) Aboriginal Cultural Heritage Audit, Renison Mine. Gordon
Grimwade & Associates. May 1999.
World Health Organisation (2004) Sulfate in Drinking-water, Background document for
the development of WHO Guidelines for Drinking-water quality.
GHD | Report for Bluestone Mines Tasmania JV Pty Ltd - D Dam Tailings Storage Facility, 32/16878 | 153
US EPA (1999) Health effects from exposure to high levels of sulfate in drinking water
workshop. Washington, DC, US Environmental Protection Agency, Office of Water (EPA
815-R-99-002).
Yanful et al, 2004. Shallow Water Cover Technology for Reactive Sulphide Tailings
Management. Geotechnical News September 2004.
This report: has been prepared by GHD for Bluestone Mines Tasmania JV Pty Ltd and may only be used and relied on by Bluestone Mines Tasmania JV Pty Ltd for the purpose agreed between GHD and the Bluestone Mines Tasmania JV Pty Ltd as set out in relevant sections of this report.
GHD otherwise disclaims responsibility to any person other than Bluestone Mines Tasmania JV Pty Ltd arising in connection with this report. GHD also excludes implied warranties and conditions, to the extent legally permissible.
The services undertaken by GHD in connection with preparing this report were limited to those specifically detailed in the report and are subject to the scope limitations set out in the report.
The opinions, conclusions and any recommendations in this report are based on conditions encountered and information reviewed at the date of preparation of the report. GHD has no responsibility or obligation to update this report to account for events or changes occurring subsequent to the date that the report was prepared.
The opinions, conclusions and any recommendations in this report are based on assumptions made by GHD described in this report. GHD disclaims liability arising from any of the assumptions being incorrect.
GHD has prepared this report on the basis of information provided by Bluestone Mines Tasmania JV Pty Ltd and others who provided information to GHD (including Government authorities)], which GHD has not independently verified or checked beyond the agreed scope of work. GHD does not accept liability in connection with such unverified information, including errors and omissions in the report which were caused by errors or omissions in that information.
GHD
2 Salamanca Square Hobart 7000 GPO Box 667 Hobart 7001 T: 03 6210 0600 F: 03 6210 0601 E: [email protected]
© GHD 2014
This document is and shall remain the property of GHD. The document may only be used for the purpose for which it was commissioned and in accordance with the Terms of Engagement for the commission. Unauthorised use of this document in any form whatsoever is prohibited.
Z:\WP\60523.docx
Document Status
Rev No.
Author Reviewer Approved for Issue Name Signature Name Signature Date
A Various S.Mcleod H.Kerr 11/04/14
B Various A.Jungalwalla H.Kerr 02/05/14
0 Various Client H.Kerr On file 12/06/2014
1 Various A Jungalwalla A Jungalwalla 18/12/14
2 H.Kerr A Jungalwalla A Jungalwalla
03/03/14
www.ghd.com