10G tOpO rapHy anD sOils - BHP · 2016. 10. 20. · Olympic Dam Expansion Supplementary...
Transcript of 10G tOpO rapHy anD sOils - BHP · 2016. 10. 20. · Olympic Dam Expansion Supplementary...
Olympic Dam Expansion Supplementary Environmental Impact Statement 2011 201
10 tOpOGrapHy anD sOils
10.1 sOil ErOsiOn
issue:
Clarification was sought on the management strategies that would be implemented to control soil erosion, particularly wind
erosion, on disturbed sites.
submissions: 2 and 106
response:
Management strategies would be developed for disturbed areas where the potential for soil erosion has been identified.
Section 10.3.3 and Figures 10.5 and 10.6 of the Draft EIS identified the areas of low, medium, high and very high erosion potential
in the EIS Study Area.
Given the relatively flat terrain and the small, contained catchments in most of the area, standard management practices would
control erosion in those sections with low and moderate erosion potential (i.e. predominantly the southern infrastructure corridor
and the southern route for the gas pipeline corridor options). Such practices include minimising the area of disturbance and
stockpiling topsoil and cleared vegetation for subsequent re-spreading over disturbed areas to promote vegetation regrowth
(refer Section 10.5.1 of the Draft EIS).
Where project infrastructure is to be located in soils of high and very high erosion potential, such as along sections of the northern
route for the gas pipeline corridor options, an Erosion and Sediment Control Plan (ESCP) would be developed before disturbance
works began. Depending on which gas pipeline option was chosen, the ESCP would address dunefield areas associated with the
Strzelecki, Collina and Hope land systems, undulating downs and rolling hills in the Mumpie soil unit, and the bed, banks and
overflow channel areas of the main watercourses. These areas are most susceptible to erosion caused by wind and rain if surface
cover is disturbed (as discussed in Section 10.5.1 and Appendix U of the Draft EIS). Erosion control measures may include
minimising the disturbance footprint; minimising the length of pipeline trench open at any given time; reinstating ground cover
as soon as practicable; watering disturbed surfaces, particularly during periods of high wind; and limiting construction traffic
movement over disturbed areas. Monitoring of disturbed areas and erosion control structures (if installed) would occur during
construction activities, particularly after high rainfall and wind events, and would continue after construction until the disturbed
areas were stabilised.
While soil types in the areas proposed for the landing facility and desalination plant only have a ‘low’ erosion potential, additional
erosion control measures and site-specific ESCPs would be implemented at these sites to ensure that sediment generated from
construction activities did not enter the marine waters (refer Section 10.5.1 of the Draft EIS). As for the high and very high
erosion-prone areas discussed above, the ESCP for the landing facility and desalination plant would be prepared before disturbance
works began (as was shown in Figure 24.4 of the Draft EIS).
Olympic Dam Expansion Supplementary Environmental Impact Statement 2011202
10.2 aciD sulfatE sOils
issue:
It was requested that additional investigations be undertaken and a draft Acid Sulfate Soil Management Plan be prepared
and submitted before any construction activity at the proposed landing facility and water supply pipeline began.
submission: 2
response:
As discussed in Section 10.3.3 of the Draft EIS, risk mapping of acid sulfate soils (ASS) suggests that coastal ASS may occur in
some sections of the EIS Study Area (refer to Figure 10.7 of the Draft EIS, reproduced in the Supplementary EIS as Figure 10.1).
Field sampling and analysis were undertaken at 14 sites that were considered most likely to support ASS. Section 10.5.2 of the
Draft EIS discussed the potential disturbance to ASS near the proposed landing facility and adjacent to Port Bonython Road (for
linear infrastructure). Investigations undertaken for the Draft EIS indicated that these soils have a low acid-generating potential
and could be effectively managed. As noted in Section 10.5.2 of the Draft EIS, and confirmed again here, further investigations
would be conducted during the detailed design phase (i.e. once the final disturbance footprints had been determined) to further
quantify the acid-generating potential of these soils.
As noted in Section 10.6 and Appendix U (Environmental Management Program ID1.1) of the Draft EIS, an ASS Management Plan
would be prepared before construction began in areas where the disturbance of potential acid sulfate soils was confirmed by
field investigations. The Plan would detail the required soil handling methods and lime dosing rates. As shown in Figure 24.4 of the
Draft EIS (reproduced here as Figure 10.2) ASS Management Plans would be prepared six months before construction activities for
the water supply pipeline (areas adjacent to Port Bonython Road), landing facility and transmission line began.
10.3 fOssils
issue:
Further information was requested on the potential impact on fossils in the vicinity of the proposed gas pipeline corridor
options, particularly in relation to the Lake Palankarinna and Lake Callabonna fossil reserves.
submission: 1
response:
There would be no direct disturbance to these fossil reserves as a result of the project.
As discussed in Section 10.3.4 and shown in Figure 10.8 of the Draft EIS (reproduced in the Supplementary EIS as Figure 10.3),
both the Lake Palankarinna and the Lake Callabonna fossil reserves are outside the EIS Study Area. The Lake Palankarinna reserve
is 30 km north of the nearest gas pipeline corridor option, while the Lake Callabonna reserve is about 1 km from the study corridor
of the nearest gas pipeline corridor option – and therefore at least 6 km from the proposed centre-line of a gas pipeline easement
(the study corridor was 5 km wide on each side of the proposed centre-line).
Any potential indirect impacts would be managed by locating temporary construction camps away from the fossil reserves, and,
if deemed desirable by the Department of Sustainability, Environment, Water, Population and Communities (SEWPaC), appropriate
information about the importance of the fossil reserves would be included in the contractor induction programs. As concluded in
Section 10.6 of the Draft EIS, the likelihood of encountering fossils in the EIS Study Area is low and the residual impact was
categorised as negligible.
Olympic Dam Expansion Supplementary Environmental Impact Statement 2011 203
OLYMPICDAM
See inset 2
See inset 1
Areas of potentialdisturbance to
inland ASS
LakeWindabout
PointLowlyWhyalla
Pimba
Woomera
Andamooka
Roxby Downs
Port Augusta
LakeMacFarlane
Lake Dutton
IslandLagoon
Lake Torrens
UpperSpencer Gulf
BH7BH6
BH5
BH4
BH3BH2
BH1
BH17
BH16
kp80
kp60
kp40
kp20
kp320
kp300
kp280
kp260
kp240
kp220
kp200
kp180
kp160
kp140
kp120
kp100
ASS sample locations
Kilometre point (kp)
Gas pipeline alignment options
Water pipeline alignment
Transmission line alignments
Rail alignment
Access corridor
Existing Olympic Dam Special Mining Lease
Existing Roxby Downs Municipality
EIS Study Area
Coastal Acid Sulfate Soil risk (CSIRO)
Low
Moderate
High
BH14
BH15
BH13BH12
BH9
BH8
BH10
KP10
0 5 10 15 20 25km
Inset 2Point Lowly
Investigation AreaInset 1
Port AugustaInvestigation Area
Moomba
Whyalla
Adelaide
Port Pirie
Port Augusta
Roxby Downs
Figure 10.1 Coastal acid sulfate soils (ASS), risk mapping and areas of potential disturbance to inland ASS
Olym
pic Dam
Expansion Supplementary Environm
ental Impact Statem
ent 2011204
PROJECT COMPONENT
EMS review and update
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4Year 0 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10
Q3 Q4
Removal of overburden
Mining of first ore
Desalination plant
Metallurgical plant
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
EMS documents including EM Program and:
Greenhouse Gas Management Plan
Weed Management Plan
Native Vegetation Management Plan
Heritage Management Protocol
Social Management Plan
Aboriginal Engagement Plan
Traffic Management Plan
PREDICTED CONSTRUCTION PERIODBased on government and BHP Billiton Board approval Q1, 2010
Pimba intermodal
Transmission line
Gas power plant/pipeline
Roxby Downs expansion
Hiltaba Village
Airport
Darwin Port
Rail
Landing facility
Sulphur handling facility
Access corridor
Water supply pipeline
EMM, EM Program and MPs – 3 year regulatory review
Baseline dust monitoring
Dust Management Plan
Acid Sulfate Soil Management Plan
Stormwater Management Plan
Erosion and Sediment Control Plan
Noise Management Plan
Radioactive Waste Management Plan
Ballast Water Management Plan – Marine
Silt and Sediment Management Plan – Marine
Blasting Management Plan
Marine F/F and WQ MP
Marine F/F and WQ (Baseline)
Figure 10.2 Schedule for environmental management documentation
Olym
pic Dam
Expansion Supplementary Environm
ental Impact Statem
ent 2011205
OLYMPICDAM
Lyndhurst
Leigh Creek
Marree
Finniss Springs
Murnpeowie
Lake Eyre North
Lake Torrens
Lake Frome
Lake Eyre South
Lake Blanche
LakeGregory
Moomba
Andamooka
Roxby Downs
kp80
kp60
kp40
kp20
kp440
kp420
kp400
kp380
kp360
kp340
kp320
kp300
kp280
kp260kp240kp220
kp560
kp540
kp520
kp500
kp480
kp460
kp440
kp420
kp400
kp380kp360
kp340
kp320
kp300
kp280kp260
kp240kp220kp200
kp180
kp160
kp140
kp120
kp100
Lake CallabonnaFossil Reserve
Lake PalankarinnaFossil Reserve
Moomba
Whyalla
Adelaide
Port Pirie
Roxby Downs
Port Augusta
0 10 20 30 40 50km
Kilometre point (kp)
Gas pipeline alignment options
Fossil Reserve
Eyre Formation
Bulldog Shale
Existing Olympic Dam Special Mining Lease
Existing Roxby Downs Municipality
EIS Study Area
Figure 10.3 Geological units known to contain fossils along the gas pipeline corridor options
Olympic Dam Expansion Supplementary Environmental Impact Statement 2011206
10.4 sOil cOntaminatiOn
issue:
Concern was raised that mining and processing activities associated with the proposed expansion could result in localised
impacts on the soil in the vicinity of Olympic Dam.
submission: 62
response:
As described in Section 10.5.4 of the Draft EIS, the potential for mining and processing activities to contribute to soil contamination
in the Special Mining Lease (SML) was assessed and categorised as low. In the area outside the SML the potential was categorised as
negligible. While elevated concentrations of metals and other potential contaminants (including radionuclides) present in
stormwater run-off from on-site facilities such as the metallurgical plant, hardstand areas and the rock storage facility (RSF) may
lead to localised soil contamination, stormwater would be controlled in defined management areas and there would be no
discharge of stormwater from the SML (refer Section 11.5.1 of the Draft EIS and Section 11.1 of the Supplementary EIS for details).
Post-closure, Section 23.8.3 of the Draft EIS noted that potentially contaminated soils in the SML would be assessed and
remediated as specified in the amended site contamination provisions (2007) of the Environmental Protection Act 1993, the
National Environment Protection (Assessment of Site Contamination) Measure 1999 (NEPC 1999), and/or other relevant legislation
at that time that addressed contamination.
Accidental spills of fuel and other hazardous materials have the potential to result in soil contamination. As discussed in Section
22.6.8 of the Draft EIS, transport, handling and storage of fuel and other hazardous materials in the SML would be in accordance
with the relevant state and Australian statutory requirements. As a minimum, the South Australian Environment Protection
Authority standards would be used (EPA Guideline 080/07) (EPA 2007), which require bund sizes and volumes to be 120% of the net
capacity of the largest tank and 133% for flammable material. The objective, as with the current operation, is to prevent spills from
occurring and, if they do occur, to contain the spillage. Current spill management and reporting procedures would continue to be
implemented and updated as required for the expanded operation.