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Bluestone Mines Tasmania JV Pty Ltd D Dam Tailings Storage Facility Development Proposal and Environmental Management Plan March 2015

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Bluestone Mines Tasmania JV Pty Ltd D Dam Tailings Storage Facility

Development Proposal and Environmental Management Plan

March 2015

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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.

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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

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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

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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

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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.

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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

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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;

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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.

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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 

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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 

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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 

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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 

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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

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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

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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.

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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.

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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.

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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

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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.

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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.

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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   

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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;

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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.

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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.

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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

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Figure 2-2 Cross Sections

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A) Starter Dam

B) Final Embankment

Figure 2-3 Embankment at Stage 1 and Final level

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Figure 2-4 Seepage Control Features

Figure 2-5 Drainage Features

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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

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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.

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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.

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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.

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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),

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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.

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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.

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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.

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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.

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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.

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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

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-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

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90

09

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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

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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.

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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.

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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

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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.

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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:

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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

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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

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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)

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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).

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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.

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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.

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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:

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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.

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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.

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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.

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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

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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)

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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

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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)

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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

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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

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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);

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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

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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).

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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,

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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.

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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).

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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

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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.

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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.

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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)

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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

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,000

5,373

,000

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,500

5,373

,500

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,000

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,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

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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

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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.

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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

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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.

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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.

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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)

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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

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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:

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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:

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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).

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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).

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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.

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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.

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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

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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.

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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.

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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.

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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.

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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

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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

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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).

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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.

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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.

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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.

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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

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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.

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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:

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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

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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.

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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

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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;

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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.

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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.

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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.

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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;

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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

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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).

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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.

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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.

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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

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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;

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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.

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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

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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.

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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;

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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).

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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.

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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

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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.

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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.

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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.

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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.

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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.

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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.

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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

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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.

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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.

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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;

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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:

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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

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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.

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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. 

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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. 

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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. 

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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. 

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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.

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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.

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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.

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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.

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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

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