OLYMPIC DAM Environmental Management and ... - Minerals

OLYMPIC DAM Environmental Management and Monitoring Report 1 July 2010 – 30 June 2011 Report No. ODENV 050

1 JULY 2010 - 30 JUNE 2011

BHP BILLITON OLYMPIC DAM ENVIRONMENTAL MANAGEMENT AND MONITORING REPORT

OLYMPIC DAM ENVIRONMENTAL MANAGEMENT AND MONITORING REPORT 1 JULY 2010 - 30 JUNE 2011 The Hon. Tom Koutsantonis MP Minister for Mineral Resources Development PO Box 2832 ADELAIDE SA 5001 DISTRIBUTION Department of Primary Industries and Resources South Australia (PIRSA)

Chief Inspector of Mines

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Department of Environment and Natural Resources (SA)

CE Dept of Environment and Natural Resources

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Senior Scientific Officer – Pastoral Land Management – Land and Biodiversity Services Principal Scientific Officer – Pastoral Program

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1 CD copy

CE Environment Protection Authority

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EPA Licence Coordinator Manager Mining and Environment Group Radiation Protection Branch

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Department For Water (SA)

CE Dept For Water Senior Hydrogeologist

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Great Artesian Basin Coordinating Committee

The Chair

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South Australian Arid Lands Natural Resources Management Board

The Chair

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Environment Protection Authority (SA)

EXECUTIVE SUMMARY

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1 JULY 2009 – 30 JUNE 2010

INTERNAL DISTRIBUTION BHP Billiton Adelaide

BHP Billiton Olympic Dam

President Uranium Vice President External Affairs Corporate Lawyer Vice President HSEC (Health, Environment and Community) Manager Sustainability Manager Radiation Services

1 CD copy 1 CD copy

Asset President Head of Production General Manager Mine General Manager Surface General Manager Services Head of HSEC Manager Environment and Radiation Superintendent Environment Superintendent Radiation & Occupational Hygiene Environment Section Library Records Centre

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Safety,

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1 CD copy 1 CD copy 1 CD copy 1 CD copy 1 CD copy 1 CD copy 1 CD copy 1 CD copy 2 hard copies 2 CD copies 2 hard copies 1 CD copy

EXECUTIVE SUMMARY

1 JULY 2010 - 30 JUNE 2011


Table of Contents 1

EXECUTIVE SUMMARY .......................................................................... 2

1.1 1.2 1.3 1.4

Overview.............................................................................................................. 2 Major Achievements ............................................................................................ 2 Monitoring Summary ........................................................................................... 2 Future Challenges ............................................................................................... 4

2

ENVIRONMENTAL MANAGEMENT PROGRAM (EMP) IMPLEMENTATION ................................................................................. 5

2.1 2.2 2.3 2.4 2.5 2.6 2.7

ID 01 Use of Resources – Water ....................................................................... 10 ID 01 Use of Resources - Land ......................................................................... 11 ID 02 Operation of Industrial Systems – Airborne Emissions ............................ 18 ID 02 Operation of Industrial Systems – Hazardous Materials Spillage ............ 22 ID 03 Generation of Wastes – Tailings Storage System (TRS)......................... 25 ID 03 Generation of Wastes – General and Industrial Waste............................ 26 Conclusion ......................................................................................................... 28

3

GROUNDWATER MONITORING PROGRAM ....................................... 31

3.1 3.2 3.3 3.4 3.5

Groundwater Abstraction and Mine Water Balance .......................................... 31 Groundwater Levels .......................................................................................... 37 Groundwater Quality.......................................................................................... 44 Use of Mine Water for Dust Suppression .......................................................... 46 Conclusion ......................................................................................................... 48

4

GREAT ARTESIAN BASIN (GAB) WATER MONITORING PROGRAM ............................................................................................. 49

5

FAUNA MONITORING PROGRAM ....................................................... 50

5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8

Avifauna............................................................................................................. 50 Small Mammals and Reptiles ............................................................................ 52 Amphibians ........................................................................................................ 53 Feral and Abundant Species ............................................................................. 54 At-risk Species – Category 1a ........................................................................... 58 At-risk Species – Category 1b and 2 ................................................................. 60 Fauna Losses .................................................................................................... 62 Conclusion ......................................................................................................... 66

6

FLORA MONITORING PROGRAM ....................................................... 68

6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8

Emission Impacts to Vegetation ........................................................................ 68 Long Term Changes to Perennial Vegetation ................................................... 71 Land Disturbance .............................................................................................. 74 Pest Plants ........................................................................................................ 77 GAB Spring Vegetated Wetland Area ............................................................... 87 At-risk Species – Category 1 ............................................................................. 88 At-risk Species – Categories 1b and 2 .............................................................. 91 Conclusion ......................................................................................................... 92

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AIRBORNE EMISSIONS MONITORING PROGRAM ............................ 93

EXECUTIVE SUMMARY

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1 JULY 2009 – 30 JUNE 2010

7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8

Smelter 2 Emissions .......................................................................................... 93 Calciner Emissions ............................................................................................ 95 Slimes Treatment Plant Emissions .................................................................... 96 Ambient Sulphur Dioxide (SO2) ......................................................................... 97 Fugitive Particulate .......................................................................................... 101 Results/Discussion .......................................................................................... 102 Raise Bore Ventilation Shaft Emissions .......................................................... 108 Conclusion ....................................................................................................... 110

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ENERGY USE AND GREENHOUSE GAS EMISSIONS ..................... 111

8.1 8.2 8.3

Energy Use ...................................................................................................... 111 Greenhouse Gas Emissions ............................................................................ 112 Conclusion ....................................................................................................... 113

9

RADIATION DOSE TO MEMBERS OF THE PUBLIC MONITORING PROGRAM .................................................................. 114

9.1 9.2

Dose to Members of the Public........................................................................ 114 Conclusion ....................................................................................................... 122

10

WASTE MONITORING PROGRAM .................................................... 123

10.1 10.2 10.3 10.4 10.5 10.6 10.7

Tailings Storage Facility (TSF) ........................................................................ 123 Evaporation Ponds (EPs) ................................................................................ 136 Mine Water Disposal Pond (MWDP) ............................................................... 141 Site and Olympic Village Sewage Ponds......................................................... 142 Waste Management Centre ............................................................................. 143 Miscellaneous Hazardous Wastes ................................................................... 144 Conclusions ..................................................................................................... 145

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REFERENCES .................................................................................... 146

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GLOSSARY OF TERMS ..................................................................... 149

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APPENDIX 1: SUMMARY OF EXTERNALLY REPORTABLE SPILLS ................................................................................................ 152

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APPENDIX 2: METEOROLOGICAL DATA ....................................... 153

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APPENDIX 4: CONSULTANTS UTILISED BETWEEN 1 July 2010 – 30 June 2011 ........................................................................... 156

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EXECUTIVE SUMMARY

1 JULY 2010 - 30 JUNE 2011


List of Figures Figure 2-1: Figure 2-2: Figure 2-3: Figure 2-4: Figure 2-5: Figure 2-6: Figure 2-7: Figure 2-8: Figure 2-9: Figure 2-10: Figure 2-11: Figure 2-12: Figure 2-13: Figure 3-1: Figure 3-2: Figure 3-3: Figure 3-4: Figure 3-5: Figure 3-6: Figure 3-7: Figure 3-8: Figure 3-9: Figure 3-10: Figure 3-11: Figure 3-12: Figure 3-13: Figure 5-1: Figure 5-2: Figure 5-3: Figure 5-4: Figure 5-5:

Rehabilitation of a road to the TSF5 soil stockpile ................................. 13 Contours are created in northern TSF5 soil stockpile to reduce erosion and to help promote native vegetation growth .......................... 14 BEFORE – regenerated Athel Pines along Eagle way .......................... 15 AFTER – regenerating stumps were uprooted and left in situ ............... 15 Example of signage at Myall Grove drain outlet .................................... 16 June 2011 dashboard ............................................................................ 17 Total notifiable emissions trend ............................................................. 19 Salt damage to surrounding vegetation ................................................. 20 Site immediately after initial remediation works ..................................... 21 Vegetation recovering approx 12mths after initial remediation work ....................................................................................................... 21 Number of radioactive process material spill events recorded in each area FY07 to FY11. ....................................................................... 24 Area of liquor stored on TSF Cells 1 – 4 during FY11 ........................... 27 Olympic Dam site layout ........................................................................ 29 Olympic Dam regional bore locations .................................................... 32 Olympic Dam site area bore locations ................................................... 33 Simplified Olympic Dam hydrogeological cross-section ........................ 35 Site groundwater abstraction ................................................................. 36 Mine water balance summary FY11 (ML/d) ........................................... 37 TSF area groundwater levels (mAHD) - Andamooka Limestone aquifer .................................................................................................... 39 Change in groundwater elevation along an east-west crosssection from LT19 to LT18, through the centre of the TSF .................... 40 Groundwater levels for Andamooka Limestone bores in the vicinity of the TSF .................................................................................. 40 Groundwater levels for Andamooka Limestone bores in the vicinity of Roxby Downs (LR) and the Mine Water Pond (LM) ............... 41 Groundwater levels for exploration drill holes in the vicinity of the underground mine .................................................................................. 42 Mine area groundwater levels (mAHD) - Arcoona Quartzite aquifer .................................................................................................... 43 Mine water sample 238U levels and upper limit, FY11 ............................ 47 Mine water sample 226Ra levels and upper limit, FY11 .......................... 48 Abundance of Crested Bellbirds (CBB) in each of the monitoring zones (± 1 standard error). .................................................................... 51 Abundance of insectivorous feeding flock (IFF) species in each of the monitoring zones (± 1 standard error).............................................. 51 Impact footprint of the bioindicator bird species during FY10 and FY11 periods.......................................................................................... 52 Impact footprint of reptiles and small mammals during FY10 and FY11 periods.......................................................................................... 53 Three sampling sessions moving average (per km2) for rabbit abundance at three transects in the Olympic Dam region ..................... 56

EXECUTIVE SUMMARY

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Figure 5-6: Figure 5-7: Figure 5-8: Figure 5-9:

Figure 5-10:

Figure 5-11:

Figure 5-12: Figure 6-1: Figure 6-2: Figure 6-3:

Figure 6-4: Figure 6-5:

Figure 6-6:

Figure 6-7: Figure 6-8: Figure 6-9: Figure 6-10: Figure 6-11: Figure 6-12: Figure 6-13: Figure 7-1: Figure 7-2: Figure 7-3: Figure 7-4:

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1 JULY 2009 – 30 JUNE 2010

Three sampling sessions moving average (per km2) for cat abundance at three transects in the Olympic Dam region ..................... 57 Three sampling sessions moving average (per km2) for fox abundance at three transects in the Olympic Dam region ..................... 57 Three sampling sessions moving average (per km2) for kangaroo abundance at three transects in the Olympic Dam region ..................... 58 Monthly summary of weekly monitoring results for FY11, showing total number of animals (birds, mammals and reptiles) recorded within the TRS ........................................................................................ 63 Quarterly summary of all weekly monitoring results, showing total number of animals (birds, mammals and reptiles) recorded within the TRS .................................................................................................. 64 Monthly summary of opportunistic observation results for FY11, showing total number of animals (birds, mammals and reptiles) recorded within the TRS......................................................................... 64 Monthly summary of number of water birds recorded at local nontoxic water bodies in comparison to TRS during FY11 .......................... 65 Location of radial sample sites and front sites monitored in FY11 ......... 70 Modelled distribution of symptoms in FY11 in and about the operation ................................................................................................ 71 Modelled surface of Simpson’s index. The contours represent the modelled level of dominance based on the values from the sample sites (red dots) ........................................................................... 74 Disturbance on the SML between June 2010 and July 2011 ................. 76 Athel Pine control efforts continued on the SML during FY11. Seven regenerating Athel Pine plants were controlled along Eagle Way. Photo taken 5 weeks after control efforts undertaken ........ 79 Control efforts of Innocent Weed within the Myall Grove reserve during summer FY11. Example of ‘Noxious Weed’ signage installed at earth drains in Roxby Downs, where Innocent Weed infestations are known to occur.............................................................. 79 Distribution of Extreme and High risk weed species on the SML in FY11....................................................................................................... 80 Distribution of weed species at Olympic Dam Village (within the Municipal Lease) in FY11 ....................................................................... 81 Distribution of weed species in the Roxby Downs urban area (in the Municipal Lease) in FY11................................................................. 82 Distribution of weed species in the Arid Recovery reserve in FY11 ....... 83 Distribution of weed species on Andamooka Station (including Andamooka township) in FY11 .............................................................. 84 Distribution of weed species on Roxby Downs Station and Purple Downs Station in FY11........................................................................... 85 Distribution of weed species on Stuarts Creek Station in FY11 ............. 86 Calciner particulate emissions sample run averages ............................. 96 Modelled maximum 1-hour average ground level SO2 concentration, FY11 ............................................................................... 98 Modelled maximum 24-hour average ground level SO2 concentration, FY11 ............................................................................... 99 Modelled average annual ground level SO2 concentration, FY11........ 100

EXECUTIVE SUMMARY

1 JULY 2010 - 30 JUNE 2011


Figure 7-5: Figure 7-6:

Passive dust monitoring site locations ................................................. 103 Annual passive dust deposition rates measured at monitoring sites, FY11 ........................................................................................... 104 Figure 7-7: Dust deposition rate by month at sites south of Olympic Dam ............ 105 Figure 7-8: Annual dust deposition rate for sites south of Olympic Dam ............... 105 Figure 7-9: Annual 238U deposition rates measured at monitoring sites, FY11 ...... 106 Figure 7-10: Annual 238U deposition rate by site ...................................................... 107 Figure 7-11: Modelled distribution of limestone dust deposition in FY11 ................. 108 Figure 7-12: Monthly average of daily salt deposition rate, at monitoring sites 100m from raise bore ........................................................................... 109 Figure 9-1: Environmental Radiation Monitoring Sites ........................................... 115 Figure 9-2: FY11 radon decay product monthly averages, including five-year trends ................................................................................................... 117 Figure 9-3: 238U concentration for the previous 5 years (in TSP and PM10) ........... 118 Figure 9-4: 230Th concentration for the previous 5 years (in TSP and PM10) .......... 119 Figure 9-5: 226Ra concentration for the previous 5 years (in TSP and PM10) ......... 119 Figure 9-6: 210Pb concentration for the previous 5 years (in TSP and PM10) ......... 120 Figure 9-7: 210Po concentration for the previous 5 years (in TSP and PM10) ......... 120 Figure 9-8: Total TSP and PM10 concentration for the previous 5 years ................ 121 Figure 9-9: Total effective dose .............................................................................. 122 Figure 10-1: TSF Supernatant Pond areas .............................................................. 124 Figure 10-2: TRS aerial photograph – July 2011 ..................................................... 126 Figure 10-3: Tailings Solids, Liquor and Tailings Density as % Solids ..................... 127 Figure 10-4: TSF Cell 4 Underdrainage Pumping Rate ........................................... 128 Figure 10-5: Elevation of tailings in TSF cells .......................................................... 129 Figure 10-6: TSF Cells 1 – 4 Liquor Balance – Inputs, FY11 ................................... 130 Figure 10-7: TSF Cells 1 – 4 Liquor Balance – Outputs, FY11 ................................ 130 Figure 10-8: Location of perimeter features monitored regularly ............................. 132 Figure 10-9: Photo of location 3 in August 2011 showing buttress .......................... 133 Figure 10-10: Schematic cross section through south side of TSF Cell 1 – June 2011 ..................................................................................................... 133 Figure 10-11: TSF Cell 1 South Wall Piezometer Hydrographs ................................. 134 Figure 10-12: TSF Cell 3 daily seepage liquor flow.................................................... 134 Figure 10-13: TSF Cell 3 liquor analyses ................................................................... 135 Figure 10-14: Photograph of Location 13B looking North in July 2011 ...................... 136 Figure 10-15: EP1 and EP2 Liquor Balance – cumulative apparent evaporation trends ................................................................................................... 138 Figure 10-16: EP3 Liquor Balance – cumulative apparent evaporation trend ............ 139 Figure 10-17: EP4 Liquor Balance – cumulative apparent evaporation trend ............ 139 Figure 10-18: EP5 Liquor Balance – cumulative apparent evaporation trend ............ 140 Figure 10-19: All EP Liquor Balance – cumulative apparent evaporation .................. 140 Figure 10-20: Evaporation pond capacity................................................................... 141 Figure 14-1: Annual rainfall FY11............................................................................. 153 Figure 14-2: Wind rose, FY11 .................................................................................. 154 Figure 14-3: Corrected Wind rose, FY10 ................................................................. 155

EXECUTIVE SUMMARY

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1 JULY 2009 – 30 JUNE 2010

List of Tables Table 2-1: Table 2-2: Table 3-1: Table 3-2: Table 3-3: Table 5-1: Table 5-2: Table 5-3: Table 6-1: Table 6-2: Table 6-3: Table 6-4: Table 6-5: Table 6-6: Table 6-7: Table 7-1: Table 7-2: Table 7-3 Table 7-4: Table 8-1: Table 8-2: Table 10-1:

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FY11 EMP Implementation Summary ...................................................... 6 Olympic Dam Progressive Rehabilitation conducted prior to FY11 ....... 12 Groundwater chemistry data for bores located in the vicinity of Olympic Dam.......................................................................................... 45 Upper limits for radionuclide content in dust suppression water ............ 46 Radionuclide analysis for dust suppression water ................................. 47 Summary of rabbit, cat, fox and kangaroo numbers (per square kilometre), showing historical abundance, FY10 and FY11 ................... 56 Cat stomach analysis results ................................................................. 58 Category 1b &2 species recorded in the Olympic Dam and wellfields region for FY11 ....................................................................... 61 Areas of modelled impact for symptoms since FY07 and change between FY10 and FY11 (areas modelled to the nearest 50ha) ........... 70 Changes in quadrat species counts FY10-11, for sites sampled in both years (n=44 sites) .......................................................................... 73 Changes in the total number of plants FY07-11, for sites sampled in over those years ................................................................................. 73 Areas of disturbance on the SML from June 2010 to July 2011 ............ 75 Pest plant species that pose an extreme or high risk ............................. 78 Changes in Eriocaulon carsonii abundance, FY10 – FY11 (n=131) ................................................................................................... 89 Changes in Eriocaulon carsonii abundance, baseline – FY11 (n=103) ................................................................................................... 90 Smelter 2 Stack Sampling Results June 2011 ....................................... 94 Measured particulate concentrations in Calciner Emissions (mg/Nm3) ................................................................................................ 95 Classification of limestone dust deposition on ground surfaces ........... 101 Modelled impact footprint for limestone dust deposition and change FY10-FY11 (areas modelled to the nearest 50 ha) ................. 107 Actual results of Energy Efficiency for June 2011 ................................ 111 Actual results of Carbon Equivalent Intensity for June 2011................ 113 List of perimeter features including their location, discovery date and status............................................................................................. 131

EXECUTIVE SUMMARY


1 JULY 2009 – 30 JUNE 2010

1 EXECUTIVE SUMMARY 1.1 Overview This report represents the first annual report under the approved three year FY11-FY13 Environmental Protection and Management Program (EPMP). Considerable progress against actions and improvement targets in the FY11 EMP was made during the reporting period, with 75 percent of actions completed. Actions not completed during the reporting period will be progressed as a priority during FY12.

1.2 Major Achievements Following is a list of major achievements for the reporting period:     

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Reducing flow of water from pastoral bores by 4ML/d from the FY08 baseline; Maintaining an industrial water efficiency of 1.12kL/t at an annual production rate of 10Mt; Updating the existing hydrogeological model to include additional spring groups and information from new monitoring bores; The establishment of Energy and Water reduction cost curves to evaluate abatement opportunities; The establishment of Energy and Water Steering committees, with representatives from all departments, to ensure a coordinated approach to energy and water management across site; Reviewing our Environment and Indigenous Heritage Clearance Permit procedure to include the Native Vegetation Management Plan and Significant Environmental Benefit requirements; Update and submission to Government of the 2011 Closure and Rehabilitation Plan; Rehabilitation of TSF5 construction support areas; and, Significant improvements in streamlining data collection of measurements of energy and greenhouse gas emission data.

1.3 Monitoring Summary During the reporting period, ongoing environmental monitoring activities were undertaken. The following are points of interest: 

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Peak groundwater level beneath the TSF for this reporting period was approximately 67mAHD. Levels are not expected to exceed the limit of 80mAHD (20m below the ground) within the next 12 months; Slightly elevated concentrations of uranium continue to be detected in the groundwater beneath the mine water disposal pond and old mine water disposal pond. Measured values do not pose a health hazard due to the low concentrations and the salinity of the water, which restrict its use for human or animal consumption; Radiation activity levels for dust suppression water were found to be consistent with those measured in FY10 and were all below the upper limit values; Avifauna indicators show that the operation appears to have measurable impacts in close proximity to the operation. The extent appears similar to the previous year; Gecko gravidity, reptile and small mammal indicators show that the operation appears to have observed impacts when in close proximity to the operation. High

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EXECUTIVE SUMMARY

1 JULY 2010 - 30 JUNE 2011

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numbers of the introduced House Mouse influenced scores from small mammal and reptile monitoring; Kangaroo, rabbit and fox numbers were lower than the long term mean on all transects; Several Category 2 listed species were recorded in the Olympic Dam SML area and the wellfields region. Three of the species recorded were within the TRS system and several other waterbird species have the potential to visit this area; There were 348 fauna mortalities recorded during weekly monitoring at the TRS in FY11, which compares to 148 for the previous reporting period. This increase was largely due to introduced house mice (over 100 recorded). The TRS Fauna project continued in FY11; The total area of detectable symptoms on vegetation for FY11 was 2,500ha. This is 100ha larger than that identified in FY10. Where areas were affected, there were likely to be slightly fewer plant symptoms than in FY10; The estimated total area of disturbance that occurred between June 2010 and July 2011 was 423.8ha; Above average rainfall in the year preceding and during FY11 resulted in a high number of pest plant infestations within the control area. Known infestation areas were monitored and controlled with a focus on Extreme risk species; Whilst there were some changes in Eriocaulon carsonii cover for individual spring units between FY10 and FY11, the changes were not significant at the spring group or impact zone level; Isokinetic sampling of the Main Smelter Stack and Acid Plant Tail Gas Stack indicated continued compliance with the requirements of EPA Licence 1301 and the Environment Protection (Air Quality) Policy 1994; The results of sampling indicate that emissions from Calciner A and B met the requirements of the Environment Protection (Air Quality) Policy 1994; No exceedance of the NEPM for ambient air quality for SO2 occurred over Olympic Dam Village or Roxby Downs Township during the reporting period; Dust and 238U deposition rates recorded during the reporting period were overall lower than those measured in previous periods due to above average rainfall throughout the year; Salt deposition rates for RB10, RB16 and RB19 are comparable to previous reporting periods. Deposition around RB21 increased during the first half of FY11, but as a result of improvement works emissions have been significantly reduced for the remainder of the year; The site wide performance for GHG emissions in FY11 was 0.60GJ/t material milled and 86kg CO2e/t material milled; The dose to members of the public due to operation-related radon progeny at both RDS and ODV were below the detection limit of 0.040mSv; The dose to members of the public due to operation-related radionuclides in dust at both RDS and ODV were below the detection limit of 0.008mSv; An effective dose to members of the public of less than the detection limit of 0.048mSv/year was calculated when background dose calculations were subtracted from measured doses. This value was less than 5% of the legislative limit of 1mSv/year; The region continued to experience above average rainfall during FY11 which has resulted in the recording of some of the lowest PM10 and radionuclide concentrations in recent history.

EXECUTIVE SUMMARY

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1 JULY 2009 – 30 JUNE 2010

Rainfall for the reporting period was 88% higher than the long term median annual rainfall. As a result of the high rainfall and significantly higher tailings deposition, the proportion of decant to evaporation ponds and liquor retained in tailings was significantly higher than the previous reporting period; The combined area of the supernatant ponds on TSF Cells 1–3 varied between 7.6ha and 25.0ha over the reporting period with an average of 15.6ha, an increase of 84% from the previous years average of 8.5ha; The supernatant pond area on TSF Cell 4 varied between 22.6ha and 42.5ha over the reporting period with an average of 30.5ha, an increase of 68% from the previous years average of 18.2ha; A number of dark areas with increased moisture were identified previously around the perimeter of the TSF and four additional areas have been identified in the current reporting period; A filter blanket was constructed over Location 3 on the South Wall of TSF Cell 1 to minimise the risk of piping; The results of the water balance indicate that the TSF has the capacity to dispose of excess liquor by evaporation although the unaccounted liquor may also include seepage from beach areas. Seepage from supernatant liquor ponds was estimated at 3% of liquor output; Evaporation Pond 2 was recommissioned in November 2010, following problems with the wave barriers in the previous reporting period; It is estimated that approximately 35,922m3 (loose fill) of general waste was transported to the Waste Management Centre in FY11; Approximately 787m3 of paper and cardboard waste was collected for recycling in FY11; and, It is estimated that approximately 7,917 tonnes of hazardous waste was disposed of within the SML in FY11.

1.4 Future Challenges         

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Continuing implementation of water use conservation and recycling initiatives, including the substitution of saline water for high quality water use; Continuing implementation of energy efficiency projects; Continuing to develop the Smelter Environmental Improvement Plan with aims to reduce the total smelter emission events; Continuing investigations into management methods relating to interactions between the TRS and fauna species; Continuing to develop, update and implement a strategy towards minimising radioactive waste produced from the mining and processing of ore; Identifying further opportunities for improvement of general and industrial waste management practices on site; Integration of DEIS/SEIS approval conditions to the EPMP documents for next Ministerial and Commonwealth Submission; Preparation for a carbon price; and, Streamlining data capture and reporting processes through the implementation of a central environmental data management system (EDMS).

EXECUTIVE SUMMARY

1 JULY 2010 - 30 JUNE 2011


2 ENVIRONMENTAL MANAGEMENT PROGRAM (EMP) IMPLEMENTATION This section includes a summary of actions and improvement targets (Table 2-1) identified for the financial year 2011 (FY11), from 1 July 2010 to 30 June 2011 under the approved three years FY11-FY13 Environmental Management Program (EMP) for Olympic Dam. Details of progress against these actions and improvement targets are provided in Table 2-1. The following progress indicators have been used to assist the reader in being able to quickly assess progress that has occurred during the reporting period: =

Activity or target achieved

=

Significant progress towards achieving the activity or target

=

Activity or target not achieved.

The approved FY11 EMP contained 68 actions with improvement targets to be achieved during the year. The performance against these commitments was: = 75%

= 9%

= 16%

A plan showing the areas of the Olympic Dam site discussed in this report is provided in Figure 2-13.

ENVIRONMENTAL MANAGEMENT PROGRAM (EMP) IMPLEMENTATION

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Table 2-1:

1 JULY 2009 – 30 JUNE 2010

FY11 EMP Implementation Summary

ID 01 Use of Resources - Water ID 1.1 Great Artesian Basin (GAB) Pressure Reductions Targets FY11: 

Reduce Etadunna and Muloorina West pastoral flows by 4ML/day from the FY08 baseline

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Maintain an industrial water efficiency of 1.12kL/t at an annual production rate of 10Mt.

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Maintain a domestic water use target of 2.6ML/day.

Action Plan FY11: 

Remove Jackboot Bore as an assessment criteria monitoring point.

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Update the existing GAB hydrogeology model based on new information and review of existing technical information.

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Continue implementation of water use conservation and recycling initiatives.

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Continue substitution of saline water for high quality water use.

ID 01 Use of Resources – Land ID 1.2 Land Disturbance and Rehabilitation Targets FY11: 

Review EIHCP procedure to include requirements of the SEB NVMP.


Identify and prioritise projects to clarify high risk assumptions identified in Olympic Dam Rehabilitation and Closure Plan.

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Continue EIHCP awareness sessions with influencing personnel and contractors as required.

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Continue to implement the site rehabilitation strategy.

ID 1.3 Spread of Pest Plants Targets FY11: 

Eradicate Athel Pines along Eagle Way on the SML through mechanical removal where past control efforts are deemed unsuccessful.

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Install signage at drain culverts where declared pest species are found.


Continue to monitor and control all known Innocent Weed infestation. Address any new infestations of Innocent Weed as required.

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Continue to progress control of Buffel Grass within the SML and Municipal Lease.

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Continue to progress control of Athel Pines within the SML and at the Olympic Dam Aerodrome.

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Continue to improve community knowledge of local pest plant species.

ID 01 Use of Resources – Energy and Greenhouse Gas Emissions ID 1.4 Climate Change Targets FY11: 

To be developed by the Energy Excellence Program during FY10 and reported through the Olympic Dam Dashboard.


Continue implementation of the energy efficiency projects.

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Improve energy and greenhouse gas emission data collection and measurement.

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Continue to establish and embed sound energy excellence procedures and systems.

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1 JULY 2010 - 30 JUNE 2011


ID 02 Operation of Industrial Systems – Airborne Emissions ID 2.1 Sulphur Dioxide Emissions Targets FY11: 

Reduce unplanned Acid Plant bypass events by 5% of the FY10 target (to less than or equal to 14 events).

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Maintain Acid Plant Tails Gas Stack exceedances at the FY10 target (to less than or equal to 16 events).

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Reduce the total unplanned emission events by 5% of the FY10 target (less than or equal to 78 events).


Implement the Smelter/Refinery Environmental Improvement Plan.

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Identify reductions to SO2 emissions after the Smelter maintenance shutdown.

ID 2.2 Particulate Emissions Targets FY11: 

Maintain annual average operational contributed PM10 concentration at sensitive receptors at equal or below the assessment criteria (ID2.2 – 7).


Continue with the annual Processing Environmental Improvement Plan process.

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Continue with the annual Mining Environment Improvement Plan process.

ID 2.3 Saline Aerosol Emissions Targets FY11: 

Reduction in the deposition of salt (NaCl) from saline aerosol emissions at RB21 salt jars by 25% from the 2009 annual average (less than 1,066mg/m2/day).


Remediate areas of saline contamination around RB21

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Develop criteria for saline emission controls at raise bores and ensure future changes to controls meet the criteria

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Install and repair fencing barricades to high priority raise bores according to the action plan developed in Q3 FY10.

ID 2.4 Radioactive Emissions Targets FY11: 

Annual operational component of radiation doses to members of the public remain below 0.3 mSv.


Continue with Monitoring Program Airborne Emissions FY11-13 and Radiation Dose to Members of the Public FY11-13.

ID 02 Operation of Industrial Systems – Hazardous Materials Spillage ID 2.5 Chemicals/Hydrocarbon Spills Targets FY11: 

Concentrator – recordable spills of chemicals and hydrocarbons less than or equal to 4.

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Hydromet – recordable spills of chemicals and hydrocarbons less than or equal to 3.

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Smelter – recordable spills of chemicals and hydrocarbons less than or equal to 5.

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Refinery – No recordable spills of chemicals and hydrocarbons.

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Infrastructure – recordable spills of chemicals and hydrocarbons less than or equal to 3.

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Mine – recordable spills of chemicals and hydrocarbons less than or equal to 14.



Supply – recordable spills of chemicals and hydrocarbons less than or equal to 1.


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1 JULY 2009 – 30 JUNE 2010


Undertake annual site chemical/hydrocarbon audit and implement actions from this audit with regards to bunding criteria and implementation.

ID 2.6 Radioactive Process Material Spills Targets FY11: 

Concentrator – reduce recordable spills of radioactive process material by 10% of the FY10 target (to less than or equal to 14 spills).



Hydromet – maintain recordable spills of radioactive process material at the FY10 target (to less than or equal to 18 spills).



Smelter – reduce recordable spills of radioactive process material by 10% of the FY10 target (to less than or equal to 11 spills).



Refinery – maintain recordable spills of radioactive process material at the FY10 target (to less than or equal to 6 spills).



Infrastructure – maintain recordable spills of radioactive process material at the FY10 target (less than or equal to 4 spills).



Mine – maintain recordable spills of radioactive process material at the FY10 target (less than or equal to 5 spills).





Continue with the annual Smelter/Refinery Environmental Improvement Plan process.



Continue with the annual Mining Environmental Improvement Plan process.



Develop an annual Infrastructure Environmental Improvement Plan.

ID 03 Generation of Wastes – Tailing Storage System (TRS) ID 3.1 Embankment Stability Targets FY11: 

Review the slope stability around the perimeter of TSF Cells 1-4 using actual measured pore pressure distributions and confirm the factors of safety for embankment stability.



Install a buttress and filter at the toe of the western embankment of TSF Cell 3 and the adjacent eastern section of the northern embankment of TSF Cell.


Prepare a report on the embankment stability of TSF Cells 1 to 4 using actual pore pressure monitoring data.



Complete the detailed design and construction of a buttress and filter at the toe of the western embankment of TSF Cell 3 and adjacent eastern section of the northern embankment of TSF Cell 4.



Install de-watering bore in spine of cells 3/4 to try to intercept liquor.

ID 3.2 Seepage Targets FY11: 

The groundwater level in the Andamooka Limestone aquifer outside the perimeter of TSF Cells 1 to 4 shall not rise above 80 metres AHD.


Identify and install additional liquor interception systems if required.

ID 3.3 Fauna Interaction Targets FY11: 

Initiate assessment of the potential for Sound ID as an on demand deterrent system.



Initiate assessment of the durability of the HDPE balls and netting within the TRS.


Continue trials of Sound ID acoustic recognition systems.

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1 JULY 2010 - 30 JUNE 2011




Continue trials of HDPE netting and balls within the TRS.

ID 03 Generation of Wastes – General and Industrial Waste ID 3.4 Solid Waste (Non Hazardous and Hazardous) Action Plan FY11: 

Improve data availability and integrity for tracking of wastes from source to disposal.



Set targets for waste recycling based on collected data.

ID 3.5 Radioactive Waste Targets FY11: 

Maintain the area of liquor stored in the TRS below or equal to 22ha as a monthly average.


Continue to develop, update and implement a strategy towards minimising radioactive waste produced from the mining and processing of ore.


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1 JULY 2009 – 30 JUNE 2010

2.1 ID 01 Use of Resources – Water 2.1.1 ID 1.1 Great Artesian Basin (GAB) Pressure Reductions Targets FY11: 

Reduce Etadunna and Muloorina West pastoral flows by 4ML/day from the FY08 baseline.

Following the purchase of Etadunna and Muloorina West in 2009, pastoral flow rates have been reduced in an effort to conserve water. Flow rates from pastoral bores on these leases equalled 5.42ML/day in FY08. Flow rates measured during FY11 equalled 1.30ML/day – a reduction of 4.12ML/day over the period. 

Maintain an industrial water efficiency of 1.12kL/t at an annual production rate of 10Mt.

The GAB Industrial Water Efficiency of the operation in FY11 was 1.07kL/t. Production for the year (total material milled) was 10.5Mt. The achievement of 1.07kL/t equalled FY09 as the most water efficient year on record for the operation. 

Maintain a domestic water use target of 2.6ML/day.

Domestic water consumption for FY11 averaged 2.11ML/day, which achieved the target. Action Plan FY11: 

Remove Jackboot Bore as an assessment criteria monitoring point.

Jackboot bore was removed as an assessment criteria monitoring point for Wellfield A for the FY12 reporting period, however it still applies to Wellfield B. Discussions are continuing regarding a proposal for the Ongoing Sustainable Management for the GAB and part of this includes identifying alternative monitoring points. 

Update the existing GAB hydrogeology model based on new information and review of existing technical information.

Numerical models have been used for more than 15 years to simulate groundwater flow in the south-west Great Artesian Basin (GAB) and the influence of the wellfields supplying water to Olympic Dam and Roxby Township. Several groundwater models have been created, from the initial GAB95 model, through successive improvements and more and better data to the ODEX model families. The following improvements were completed during the reporting period: 

ODEX6 was created to distinguish the new model from the previous version (ODEX5).



The ODEX6 model domain was extended to include the western springs, from Anna to Strangways; and to place new information from the new monitoring bores MB5 and MB6 into better hydrogeological context.

•

The ODEX6 model was reviewed and enhanced between Jackboot Bore and the western springs to improve drawdown predictions. New bore data and the results of recent hydrostratigraphic and geophysical work were included to the west of Jackboot Bore.

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1 JULY 2010 - 30 JUNE 2011




•

Monitoring (drawdown data) and abstractions, including pastorals and Moomba, were updated to June 2011.

•

The time periods ODEX6 uses were improved to better reflect the changes in wellfield abstractions related to the Clark Shaft outage.

Continue implementation of water use conservation and recycling initiatives

Implementation of the following water conservation and recycling initiatives began in FY11 and are expected to reduce water use in FY12:   

Increasing the equipment capacity for recycling of tailings liquor to the metallurgical plant Covering an open water storage at the desalination plant to reduce evaporative losses

Continue substitution of saline water for high quality water use.

Saline water continues to be used in lieu of high quality water where feasible, including use in CAF, road watering and construction. Saline water is not being used to augment the process water stream as this results in an unacceptable increase in chloride in the system, which effects plant performance. Research is continuing into overcoming the technical barriers of high chloride in the system and its negative impact. Implementation began on a project which will use saline water as a substitute for high quality water at the Mine vehicle wheelwash.

2.2 ID 01 Use of Resources - Land 2.2.1 ID 1.2 Land Disturbance and Rehabilitation Targets FY11: 

Review EIHCP procedure to include requirements of the SEB NVMP

The Environmental and Indigenous Heritage Clearance Permit (EIHCP) procedure was reviewed to improve the efficiency of the process and to include requirements of the Significant Environmental Benefit (SEB) Native Vegetation Management Plan (NVMP) in FY11. Key outcomes from the review have resulted in:    

Identification of areas subject to a SEB offset; The addition of a SEB ratio attribute to the EIHCP spatial database; Identification of process improvements to automate SEB offset accounting; and, Identification of the requirement for a robust process and field guide for assessing SEB ratios. Continuous improvement will continue in FY12 to further improve the SEB accounting process by developing an assessment field guide and by further integrating SEB accounting requirements into the EIHCP and reporting procedure. Action Plan FY11: 

Identify and prioritise projects to clarify high risk assumptions identified in Olympic Dam Rehabilitation and Closure Plan.

As part of updating Olympic Dam’s Closure and Rehabilitation Plan, the Life of Asset (LOA) Plan has been used to derive key assumptions in calculating the provision for


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1 JULY 2009 – 30 JUNE 2010

closure costs. Some of the assumptions applied in the Closure Plan were derived from the LOA Plan, namely:   

 

The estimated life of the mine; The useful life of the site plant and equipment as suggested in the LOA Plan; Closure measures area referenced in the FY11 LOA Plan and defined in the Olympic Dam Closure Plan 2007. The FY12 Life of Asset Plan will reference closure measures as defined in the Olympic Dam Closure and Rehabilitation Plan 2011 – Submitted to Government (PIRSA) in August 2011; Rehabilitation activities conducted in FY11 will be reported in the FY12 Life of Asset Plan; and, Table 2-2 was provided by the Environment and Radiation Section for the Progressive Rehabilitation Plan document in May 2011.

Table 2-2:

Olympic Dam Progressive Rehabilitation conducted prior to FY11

Facility

Description

Area Rehabilitated

Borefield Facilities

Disturbance from the construction of the GAB water pipeline

365.6ha

Exploration

Borrow pits, Drill pads, turkey nest

14.0ha

Metallurgical Facilities

Unsealed road and mullock pile

6.4ha

Tailings Facilities

Unsealed road

0.5ha

Miscellaneous Facilities

Borrow pits, unsealed roads and other disturbances

28.0ha

Town Facilities

Unsealed roads, Olympic Dam Camp 1 and Camp E

26.1ha

TOTAL 

440.6ha

Note: Additional rehabilitation was undertaken of TSF5 stockpile areas and other areas no longer required. Rehabilitation of these areas took place following the submission of the Closure and Rehabilitation Plan and are not included in the table above.

The FY11 Annual Closure and Rehabilitation Plan review included a Closure Planning Workshop in March 2011 and Risk Assessment Workshop in June 2011. These workshops were held with the relevant internal stakeholders. The following changes were considered to update the Closure Economic Evaluation and associated Closure Risk Register: 

The mine closure date was decreased from 2084 to 2082;



No changes to Life of Asset tailings cells were required; and,



The FY12 Life of Asset Plan will update any changes.

The Annual Closure Summary Report was completed by the Olympic Dam Resources Planning and Development and Finance Departments and sent to BHP Billiton Corporate. 

Continue EIHCP awareness sessions with influencing personnel and contractors as required.

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EIHCP awareness sessions, with current information, were undertaken with key personnel and contractors. This included presentations to influencing personnel from the TSF5 construction crew, mine projects, services, exploration and drilling, and backfill. Sessions will continue throughout FY12. 

Continue to implement the site rehabilitation strategy.

With the underground nature of the operation and awareness of a possible future expansion, large scale rehabilitation works were not undertaken during FY11. EIHCP conditions require temporary disturbances to be rehabilitated where possible. This is the case for excavation works to lay cable or fix burst pipes where topsoil is respread and the earth lightly ripped to promote natural revegetation. All areas cleared for the construction of TSF5 that are no longer required for ongoing operation have been rehabilitated. This includes adding bunds into long term stockpiles to prevent erosion and ripping up compacted laydown areas (Figure 2-1 to Figure 2-2).

Figure 2-1:

Rehabilitation of a road to the TSF5 soil stockpile


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Figure 2-2:

1 JULY 2009 – 30 JUNE 2010

Contours are created in northern TSF5 soil stockpile to reduce erosion and to help promote native vegetation growth

2.2.2 ID 1.3 Spread of Pest Plants Targets FY11: 

Eradicate Athel Pines along Eagle Way on the SML through mechanical removal where past control efforts are deemed unsuccessful.

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Seven regenerating Athel Pine trees were up-rooted along Eagle Way during FY11. Past cut and swab control efforts were unsuccessful, so mechanical removal was instigated and no regeneration has been noted since. Trees ranged from 1m to 3m in height and were removed from the ground using a small excavator. Figure 2-3 and Figure 2-4 show before and after photos of Athel Pine removal efforts.

Figure 2-3:

BEFORE – regenerated Athel Pines along Eagle way

Figure 2-4:

AFTER – regenerating stumps were uprooted and left in situ



Install signage at drain culverts where declared pest species are found.

Signage displaying information regarding the presence of noxious weeds were installed at four earth drain heads within Roxby Downs, in consultation with the Roxby Downs Municipal Council. Signs were installed where infestations of Innocent Weed were known to occur and there was a risk of contaminated soil being removed for maintenance requirements (Figure 2-5).


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Figure 2-5:

1 JULY 2009 – 30 JUNE 2010

Example of signage at Myall Grove drain outlet


Continue to monitor and control all known Innocent Weed infestations. Address any new infestation of Innocent Weed as required.

Innocent weed was present at known infestation locations during the summer of FY11. Extensive physical and chemical control was undertaken on numerous occasions. Despite flooding of several drainage areas where Innocent Weed occurs during FY10 and the substantial rainfall throughout FY11, the Myall Grove infestation area appeared to be smaller and less dense than in previous years. Infestations found in earth drains that run into the larger Myall Grove reserve area continue to be actively controlled as a priority. 

Continue to progress control of Buffel Grass within the SML and Municipal Lease.

During FY11 Buffel Grass was monitored and controlled, using a combination of spot spraying and hand-pulling. The distribution of this weed has in the past been largely limited to the northern sections of Roxby Downs, particularly around the town water supply and light industrial area. During FY11, infestations of significant size were controlled along B97 Highway (Woomera to Olympic Dam). Individual infestations continue to be controlled on the Special Mining Lease and appear to be decreasing in density. Opportunistic monitoring, especially following rain, will continue in FY12. 

Continue to progress control of Athel Pines within the SML and at the Olympic Dam Aerodrome.

Progress of Athel Pine control is detailed in the ‘Targets FY11’ section of ID 1.3, above. 

Continue to improve community knowledge of local pest plant species.

During FY11, articles on ‘Pest Plants’ and the use of ‘native species’ for landscaping were submitted and published in local newspapers. Internal BHP Billiton notifications were also sent in relation to common weed species following the substantial rainfall events throughout FY11. Two Weed Management Group meetings were held during FY11, attended by regional stakeholders and government representatives.

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2.2.3 ID 01 Use of Resources – Energy & Greenhouse Gas Emissions 2.2.4 ID 1.4 Climate Change Targets FY11: 

To be developed by the Energy Excellence Program during FY10 and reported through the Olympic Dam Dashboard.

Targets for energy efficiency and greenhouse gas emissions (carbon equivalent intensity) were set for each month and reported through the Olympic Dam dashboard. Figure 2-6 shows the June 2011 results as an example. It gives the June actuals and targets and the year to date (YTD – i.e. overall result for 2011) actuals and targets. Figure 2-6 shows that overall site was close to target for energy efficiency and carbon equivalent intensity. Some of the individual plant areas achieved target and some were over target.

Figure 2-6:

June 2011 dashboard

The reason targets were not met was more related to the quality of targets, rather than a reflection of performance. FY11 was the first year targets were set in this way, since then the understanding of the drivers of energy use and greenhouse gas emissions has improved. These learnings will be applied when setting future targets. Action Plan FY11: 

Continue implementation of the energy efficiency projects.

Progress was made on projects that had an energy benefit in FY11. This was documented as part of the requirements of the federal government’s Energy Efficiency Opportunities (EEO) legislation. 

Improve energy and greenhouse gas emission data collection and measurement.

Significant improvements in streamlining data collection and measurements were made in FY11. This has reduced the time for the collation of routine monthly reports from a full day to several hours. Changes have also resulted in improved accuracy of departmental energy use and greenhouse gas emissions and for site as a whole. This in turn has facilitated a better understanding of the drivers of variation in energy use and greenhouse gas emissions. 

Continue to establish and embed sound energy excellence procedures and systems.


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1 JULY 2009 – 30 JUNE 2010

Existing procedures covering the monitoring of energy use and greenhouse gas emissions, and the energy and greenhouse gas management plan were reviewed and updated. An Energy Steering Committee was formed and imbedded in FY11, which brings together key personnel from across site to coordinate improvement actions and drive accountability for energy performance. The committee is chaired by the Manager – Environment and Radiation.

2.3 ID 02 Operation of Industrial Systems – Airborne Emissions 2.3.1 ID 2.1 Sulphur Dioxide Emissions Targets FY11: 

Reduce unplanned Acid Plant bypass events by 5% of the FY10 target (to less than or equal to 14 events).

In FY11 a change was made to the way emission events were tracked and reported. This change was made in order to shift the focus on reducing overall notifiable emission events. This was done by reviewing the internal definition around planned and unplanned events and tracking our total notifiable events rather than unplanned events. As a result of this change a target for total notifiable Acid Plant bypass events was determined. The FY11 target for Acid Plant bypass events was 23. This represents both unplanned and planned events. Actual number of Acid Plant bypass events in FY11 was 46. This represents a 100% increase in the target number. 

Maintain Acid Plant Tails Stack exceedances at the FY10 target (to less than or equal to 16 events).

Acid Plant Tails Stack exceedances were 119% above target, with 35 events recorded. 

Reduce the total unplanned emission events by 5% of the FY10 target (less than or equal to 78 events).

In FY11 a change was made to the way emission events were tracked and reported. This change was made in order to shift the focus on reducing overall notifiable emission events. This was done by reviewing the internal definition around planned and unplanned events and tracking our total notifiable events rather than unplanned events. As a result of this change a target for total notifiable emission events was determined based on a 5% reduction of the FY04-09 average. The FY11 target for total notifiable emission events was 196. The actual result for FY11 was 194 total notifiable emission events, which is under target. (Figure 2-7). When compared with the total emissions from FY09, this is a 25% reduction in the total number of emissions notifiable to Government. Because FY10 does not represent a full production year, the data has been compared with the FY09 period.

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1 JULY 2010 - 30 JUNE 2011


Number of emission events

300 250 200 150 100 50 0 FY06

FY07

Total Notifiable Emission Events

Figure 2-7:

FY08

FY09

Acid Plant Tails Stack Exceedances

FY10

FY11

Acid Plant Bypass Events

Total notifiable emissions trend


Implement the Smelter/Refinery Environmental Improvement Plan.

An action plan was developed and implemented throughout FY11. This was reviewed periodically and most actions deemed relevant were completed during FY11. The few outstanding actions will be considered in the FY12 EIP process. A significant focus was put in by the operations area in the EIP to reduce bypass events associated with the anode furnace off gas area. As a result a large reduction in emissions was observed during FY11 from this area. 

Identify reductions to SO2 emissions after the Smelter maintenance shutdown.

As a result of the Smelter maintenance shutdown that occurred in FY10 a decrease in emissions was not observed. Due to equipment being offline for an extended period of time, emission events increased due to a failure with the variable speed drive on the anode furnace four off-gas fan.

2.3.2 ID 2.2 Particulate Emissions Targets FY11: 

Maintain annual average operational contributed PM10 concentration at sensitive receptors at equal or below the assessment criteria (ID2.2 – 7).

Annual average PM10 concentrations at Olympic Dam Village (ODV) and Roxby Downs (RDS) for FY11 were below 30µg/m3. PM10 concentrations peaked in September 2010 at ODV and RDS, at 18µg/m3 and 25µg/m3, respectively. Annual average concentrations for ODV and RDS were 10.5µg/m3 and 11.1µg/m3, respectively. Action Plan FY11: 



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1 JULY 2009 – 30 JUNE 2010

An action plan was developed and implemented throughout FY11. This was reviewed periodically and most actions deemed relevant were completed during FY11. The few outstanding actions will be considered in the FY12 EIP process. 

Continue with the annual Mining Environment Improvement Plan process.

An EIP for the mine has been initiated, focusing on saline aerosol emissions from raise bores and improving controls as well as hydrocarbon management. Outstanding actions will be considered in the FY12 EIP process.

2.3.3 ID 2.3 Saline Aerosol Emissions Targets FY11: 

Reduction in the deposition of salt (NaCl) from saline aerosol emissions at RB21 salt jars by 25% from the 2009 annual average (less than 1,066mg/m2/day).

The RB21 mist eliminators were repaired in January 2010, which substantially reduced salt emissions. The FY11 annual average RB21 salt deposition result was 358mg/m2/day. RB21 salt deposition peaked in February 2011 at 1,220mg/m2/day. Action Plan FY11: 

Remediate areas of saline contamination around RB21.

During FY11 contaminated soil was removed from the eastern area surrounding RB21. Following substantial rainfall throughout the reporting period, annual and some perennial vegetation has re-established in areas previously impacted from salt deposition, see Figure 2-8, Figure 2-9 and Figure 2-10 below.

Figure 2-8:

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Salt damage to surrounding vegetation


1 JULY 2010 - 30 JUNE 2011

Figure 2-9:


Site immediately after initial remediation works

Figure 2-10: Vegetation recovering approx 12mths after initial remediation work 

Develop criteria for saline emission controls at raise bores and ensure future changes to controls meet the criteria.

Saline emission controls at raise bores have been identified and are currently being tested. Suggested controls are the installation of mist eliminators and cement wall fencing around barricades. An investigation is currently underway with a contract company to upgrade the mist eliminators and increase the raisebore fan performance, therefore reducing the need for strenuous maintenance caused by the current maintenance regime. Further investigation will also focus on the possibility of using shade cloth as an extra emission prevention device by extending it from the top of the concrete barriers to the top of the fan outlet. 

Install and repair fencing barricades to high priority raise bores according to action plan developed in Q3 FY10.


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1 JULY 2009 – 30 JUNE 2010

The installation of cement barricades to high priority raise bores are tracking well within the set timeframes, with no major problems.

2.3.4 ID 2.4 Radioactive Emissions Targets FY11: 

Annual operational component of radiation doses to members of the public remain below 0.3mSv.

Operational component of radiation doses to members of the public at Olympic Dam and Roxby Downs remained below the detection limit of 0.048mSv/year. Action Plan FY11: 

Continue with Monitoring Program Airborne Emissions FY11-13 2788 and Radiation Dose to Members of the Public FY11-13 2790.

Monitoring programs continue to be executed without any changes.

2.4 ID 02 Operation of Industrial Systems – Hazardous Materials Spillage 2.4.1 ID 2.5 Chemicals/Hydrocarbon Spills Targets FY11: 

Concentrator – recordable spills of chemicals and hydrocarbons less than or equal to 4.

Recordable spills of chemicals and hydrocarbons in the Concentrator were 25% above target with 5 events recorded in FY11. 

Hydromet – recordable spills of chemicals and hydrocarbons less than or equal to 3. Recordable spills of chemicals and hydrocarbons in the Hydromet were 100% below target with no events recorded in FY11. 

Smelter – recordable spills of chemicals and hydrocarbons less than or equal to 5.

Recordable spills of chemicals and hydrocarbons in the Smelter were 20% below target with 4 events recorded in FY11. 

Refinery – no recordable spills of chemicals and hydrocarbons.

Recordable spills of chemicals and hydrocarbons in the Refinery were above target with 2 events recorded in FY11. 

Infrastructure – recordable spills of chemicals and hydrocarbons less than or equal to 3.

Recordable spills of chemicals and hydrocarbons in Services were above target with 4 events recorded in FY11. 

Mine – recordable spills of chemicals and hydrocarbons less than or equal to 14.

Recordable spills of chemicals and hydrocarbons at the Mine were below target with 5 events recorded.

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1 JULY 2010 - 30 JUNE 2011




Supply – recordable spills of chemicals and hydrocarbons less than or equal to 1.

Recordable spills of chemicals and hydrocarbons in Supply were above target with 2 events recorded in FY11. Action Plan FY11: 

Undertake annual site chemical/hydrocarbon audit and implement actions from this audit with regards to bunding criteria and implementation.

The annual site Hydrocarbon Audit was conducted and an action plan developed for each area. The main recommendations related to specific hydrocarbon management in some areas within the surface Mine workshops and the underground mine fuel bay, including provision of spills kits and improving storage areas and bunds to avoid and capture any spillages. The main recommendation for Processing and Smelter was to improve bunds in storage areas through correct use and provision of appropriate/additional facilities. The standard of housekeeping could also be improved within each area with emphasis on increasing ownership and education.

2.4.2 ID 2.6 Radioactive Process Material Spills Targets FY11: All spills of radioactive process material during the reporting period occurred within the plant and TRS areas and did not result in harm to the environment or radiation risk to personnel. 

Concentrator – reduce recordable spills of radioactive process material by 10% of the FY10 target (to less than or equal to 14 spills).

Recordable spills of radioactive process materials in the Concentrator were 21% above target with 17 events recorded in FY11. Figure 2-11 shows the number of recordable spills of radioactive process material in FY11. 

Hydromet – maintain recordable spills of radioactive process material at the FY10 target (to less than or equal to 18 spills).

Recordable spills of radioactive process materials in the Hydromet were 22% above target with 22 events recorded. Figure 2-11 shows the number of recordable spills of radioactive process material in FY11. 

Smelter – reduce recordable spills of radioactive process material by 10% of the FY10 target (to less than or equal to 11 spills).

Recordable spills of radioactive process materials in the Smelter were 18% below target with 9 events recorded. Figure 2-11 shows the number of recordable spills of radioactive process material in FY11. 

Refinery – maintain recordable spills of radioactive process material at the FY10 target (to less than or equal to 6 spills).

Recordable spills of radioactive process materials in the Refinery were 67% below target with 2 events recorded. Figure 2-11 shows the number of recordable spills of radioactive process material in FY11.


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

1 JULY 2009 – 30 JUNE 2010

Infrastructure – maintain recordable spills of radioactive process material at the FY10 target (less than or equal to 4 spills).

Recordable spills of radioactive process materials within Infrastructure were above target with 5 events recorded. Figure 2-11 shows the number of recordable spills of radioactive process material in FY11. 45

40

Number of spill events

35

30

25 20

15

10

5

0 Concentrator

Hydromet

Smelter FY07

FY08

Refinery FY09

FY10

Mine

Infrastructure

FY11

Figure 2-11: Number of radioactive process material spill events recorded in each area FY07 to FY11. 

Mine – maintain recordable spills of radioactive process material at the FY10 target (less than or equal to 5 spills).

Recordable spills of radioactive process materials at the Mine were below target with 3 events recorded. Figure 2-11 shows the number of recordable spills of radioactive process material in FY11. Action Plan FY11: 



Continue with the annual Improvement Plan process.

Smelter

/

Refinery

Environmental


Continue with the annual Mining Environmental Improvement Plan process.

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1 JULY 2010 - 30 JUNE 2011


An EIP for the mine was developed and implemented throughout FY11. Outstanding actions will be considered in the FY12 EIP process. 

Develop an annual Infrastructure Environmental Improvement Plan.

The FY11 Infrastructure EIP was developed during the reporting period with actions entered and tracked within First Priority (FPe), an internal system for HSE management.

2.5 ID 03 Generation of Wastes – Tailings Storage System (TRS) 2.5.1 ID 3.1 Embankment Stability Targets FY11: 

Review the slope stability around the perimeter of TSF Cells 1-4 using actual measured pore pressure distributions and confirm the factors of safety for embankment stability.

Geotechnical drilling and testing was undertaken around the perimeter of TSF Cells 1-3 during FY11. A review of the stability of TSF Cells 1-3 was undertaken using this information, as well as actual pore pressure measurements. 

Install a buttress and filter at the toe of the western embankment of TSF Cell 3 and the adjacent eastern section of the northern embankment of TSF Cell 4.

The buttress was installed during FY10 as planned. Refer to Section 10 – Waste for more detail. Action Plan FY11: 

Prepare a report on the embankment stability of TSF Cells 1 to 4 using actual pore pressure monitoring data.

A report was prepared on the stability of TSF Cells 1-3 during FY11 based on results from geotechnical investigations. 

Complete the detailed design and construction of a buttress and filter at the toe of the western embankment of TSF Cell 3 and adjacent eastern section of the northern embankment of TSF Cell 4.

The buttress was installed during FY10 as planned. 

Install de-watering bore in spine of cells 3/4 to try to intercept liquor.

A de-watering bore was installed during the reporting period into the mullock spine separating TSF Cell 3 and TSF Cell 4. This was successfully commissioned and has reduced seepage reporting to the Cell 3/4 Buttress by over 95%. Refer to Section 10 – Waste for more detail.

2.5.2 ID 3.2 Seepage Targets FY11: 

The groundwater level in the Andamooka Limestone aquifer outside the perimeter of TSF Cells 1 to 4 shall not rise above 80 metres AHD.

The groundwater level in the Andamooka Limestone aquifer outside the perimeter of TSF Cells 1-4 did not rise above 80m AHD during the reporting period. The maximum level during FY11 was 67.26m AHD.


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1 JULY 2009 – 30 JUNE 2010


Identify and install additional liquor interception systems if required.

A liquor interception system is planned to be installed at Location 13A/B during FY12 as a precautionary measure. No other locations requiring liquor interception systems were identified during FY11.

2.5.3 ID 3.3 Fauna Interaction Targets FY11: 

Initiate assessment of the potential for Sound ID as an on demand deterrent system.

Completed, refer to comments under action plan FY11. 

Initiate assessment of the durability of the HDPE balls and netting within the TRS.

Completed, refer to comments under action plan FY11. Action Plan FY11: 

Continue trials of Sound ID acoustic recognition systems

Trials of sound identification software continued, to determine its efficacy at identifying waterbird species and its potential use as part of an on demand deterrent system. At this stage the SoundID system will be investigated, plans for the Marine Radar have been put on hold pending the outcomes of the SoundID trial. Assessments suggest that SoundID has the potential to be equally or more effective than a marine radar system. 

Continue trials of HDPE netting and balls within the TRS

HDPE netting and balls remained in place and were monitored throughout the reporting period. Trials are planned to continue to determine longer term durability of the materials.

2.6 ID 03 Generation of Wastes – General and Industrial Waste 2.6.1 ID 3.4 Solid Waste (Non Hazardous and Hazardous) Action Plan FY11: 

Improve data availability and integrity for tracking of wastes from source to disposal.

Several aspects of data availability and integrity were improved during FY11. The main improvement was in the recording of waste disposed to landfill. Historically recyclable material diverted from landfill wasn’t recorded, leading to an overestimation in waste disposed to landfill. Data management has been improved so that these values can be recorded and a more accurate figure calculated. Volumes of material reused around site are also captured, leading to improved data availability and integrity. Data availability has also been improved by the addition of a monthly summary for major inputs and outputs from the Resource Recovery Centre. Percentages of material to landfill, material recovered from landfill and material delivered to recycling point are reported on monthly. 

Set targets for waste recycling based on collected data.

Based on the improved data availability and integrity, targets have been set for FY12. Page 26


1 JULY 2010 - 30 JUNE 2011


2.6.2 ID 3.5 Radioactive Waste Targets FY11: 

Maintain the area of liquor stored in the TRS below or equal to 22ha as a monthly average.

The area of liquor stored in the TRS averaged 45.1ha over the reporting period with a June 2011 value of 53.5ha (Figure 2-12). Liquor area remained over target during the year due to ongoing issues with above average rainfall of 278mm, low tailings densities and reduced evaporation pond capacity. 60 50 Hectares

40 30 20 10

Target

Jun-11

May-11

Apr-11

Mar-11

Feb-11

Jan-11

Dec-10

Nov-10

Oct-10

Sep-10

Aug-10

Jul-10

0

Actual

Figure 2-12: Area of liquor stored on TSF Cells 1 – 4 during FY11 Action Plan FY11: 

Continue to develop, update and implement a strategy towards minimising radioactive waste produced from the mining and processing of ore.

Whilst no strategy document has been produced, current work on reducing radioactive waste is around disposal of redundant contaminated plant items. Minimisation of ore tailings material is generally limited to improvements in processing recoveries and efficiencies (i.e. reducing water and reagent input to limit overall volume of tails produced) and use of tailings sands as mine backfill material. A project is underway to replace the defective uranium solvent extraction crud centrifuge. Without the centrifuge operating waste volume is greater as process liquids are entrained in the crud. The centrifuge separates the crud into solids, aqueous liquor and organic solvent. This allows for the aqueous and organic to be recycled reducing water and solvent input and minimising the volume of material sent to the TSF. There are a number of demolition projects scheduled for the upcoming financial year to remove redundant plant. The Environment and Radiation section are assisting project planners assess the radioactive contamination levels in order to minimise the volume of material that will be classified as radioactive waste. Projects currently scheduled include the pilot plant and the pregnant leach solution sand filters. Scoping projects may also commence for demolition of smelter 1 and the old extraction plant. Investigation has also commenced on alternative storage options for redundant contaminated plant classified as low level radioactive waste (LLRW). LLRW is currently


Page 27


1 JULY 2009 – 30 JUNE 2010

disposed into the TSF and there is a quantity stored at the Resource Recovery Centre. The investigation will look at the feasibility of alternative sites which may be able to be made into compliant storage facilities, e.g. the old mine water disposal pond and the quarry.

2.7 Conclusion FY11 saw 75% of our targets and actions achieved; an increase of 6% from the previous reporting period. Significant progress was made on 9% of our actions and targets whilst 16% were not met. Targets met include:  

Reducing flow of water from pastoral bores by 4ML/d from the FY08 baseline; Maintaining and industrial water efficiency of 1.12kL/t at an annual production rate of 10Mt;  Updating the existing hydrogeological model to include additional spring groups and information from new monitoring bores;  Reviewing our Environment and Indigenous Heritage Clearance Permit procedure to include the Native Vegetation Management Plan and Significant Environmental Benefit requirements;  Updating the Closure and Rehabilitation Plan;  Rehabilitation of TSF5 construction support areas;  The groundwater level in the Andamooka Limestone aquifer outside the perimeter of TSF Cells 1-4 did not rise above 80m AHD during the reporting period. The maximum level during FY11 was 67.26m AHD;  Significant improvements in streamlining data collection of measurements of energy and greenhouse gas emission data;  Remediation of saline contamination areas around RB21; and,  Installation of a buttress and filter on the northwest corner of TSF Cell 3. Targets not met included:    



Three targets relating to the reduction of SO2 emissions; Four targets relating to the number of spills of chemicals and hydrocarbons; Three targets relating to the number of spills of radioactive process material; and, One target relating to area of liquor stored on the TSF due to above average rainfall and reduced capacity of evaporation ponds contributing to increased area of liquor on TSF; Continuation of trials of the SoundID acoustic recognition system for potential use as an on-demand deterrent at the TRS

Page 28


1 JULY 2010 - 30 JUNE 2011


Figure 2-13: Olympic Dam site layout


Page 29

1 JULY 2010 - 30 JUNE 2011


3 GROUNDWATER MONITORING PROGRAM 3.1 Groundwater Abstraction and Mine Water Balance 3.1.1 Background Olympic Dam abstracts groundwater from both aquifer systems within the Special Mining Lease. The shallow Andamooka Limestone is completely dewatered in the mine area with inflows into the mine only from the deeper quartzite aquifer. In the TSF area and around the process plant there is considerable saturated thickness in the limestone due to seepage induced mounding. Local groundwater is used primarily for dust suppression, construction work, underground mining operations and in the Backfill Plant. Water supply facilities include: 

Saline Wellfield, comprising several bores which intersect the Arcoona Quartzite aquifer (Figure 3-2);



Production bore LP02, located on the north side of the TSF producing from the TSF seepage mound in the Andamooka Limestone aquifer (Figure 3-2).

3.1.2 Purpose   

Monitor abstraction rates from the TSF mound and saltwater wellfield and analyse patterns of saltwater use. Maintain an understanding of the mine water balance through measurement, derivation or estimation of key parameters. Estimate groundwater discharge to the mine workings.

3.1.3 Deliverable(s)   

Review abstraction rates and trends and assess with respect to groundwater levels. Define and map the mine water balance. Estimate the degree of groundwater discharge to the mine.

3.1.4 Method Average daily production from production bore LP02 and the saltwater wellfield is monitored and recorded as the monthly average abstraction in ML/d. The mine water balance is calculated annually from a combination of measured, derived and estimated data.

GROUNDWATER MONITORING PROGRAM

Page 31


Figure 3-1:

Page 32

1 JULY 2010 - 30 JUNE 2011

Olympic Dam regional bore locations


1 JULY 2010 - 30 JUNE 2011

Figure 3-2:


Olympic Dam site area bore locations


Page 33

1 JULY 2010 - 30 JUNE 2011

Figure 3-3:


Simplified Olympic Dam hydrogeological cross-section

3.1.5 Results/Discussion LP02 – TSF Mound Abstraction from the Andamooka Limestone aquifer using production bore LP02 averaged 0.14ML/d (Figure 3-4) from July 2010 to June 2011, compared to 0.17ML/d over the previous reporting period. In previous reporting periods, water from LP02 has not been included in the mine water balance. However, this water source has been integrated with the surface and mine saline water network, and can no longer be considered a separate water source.

Saline Wellfield Saline water was abstracted from the Arcoona Quartzite throughout FY11 from the Saline Wellfield, located south of the Whenen Shaft. Some of this water from the Saline Wellfield was used in construction projects throughout the operations, whilst the remainder was discharged to the mine water disposal pond for evaporation. An average of 2.59ML/d was abstracted over the period, compared to 1.33ML/d during the previous reporting period.


Page 35


4.0

3.5

Water abstraction (ML/d)

3.0

2.5

2.0

1.5

1.0

0.5

TSF (LP02) Supply

Figure 3-4:

Jun-11

May-11

Apr-11

Mar-11

Feb-11

Jan-11

Dec-10

Nov-10

Oct-10

Sep-10

Aug-10

Jul-10

0.0

Saline Wellfield

Site groundwater abstraction

Groundwater Discharge to the Mine Groundwater inflow to the mine occurs at several intersections with the underground operations. Total natural inflow is estimated to be approximately 3.00ML/d, the majority entering via upcast raise bores. Additional natural inflow comes into the mine via other entry points, including downcast raise bores, exploration drill holes and shafts (Figure 3-5). The majority of the total inflow to the mine is exhausted to the surface as saline aerosols or moisture-laden air via upcast raise bores, estimated at around 2.50ML/d.

Mine Water Balance The mine water balance is a summary of the volume of water going into and out of the underground mine. It includes saline water abstracted from local bores that is added to surface storages and used around site. The balance presented in Figure 3-5 is generated from a combination of measured, derived and estimated data.

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1 JULY 2010 - 30 JUNE 2011


FY11 Yr Mine Water Balance Summary (ML/d) 0.8 1.1

Disposal/Losses Evaporation/Misc Losses Mine Water Disposal Pond

Supply Sources 0.0 Misc Supply 0.0 Surface Recycled Potable 2.6 Saline Borefield 0.1 Andamooka Limestone Aquifer

Surface

1.9

2.7 .

1.6 Construction Use

Total Use Underground 4.3 Saline Droppers 0.8 CAF Bleed

5.1

5.9

Natural Inflow 3.0 Underground Recycled Potable 0.3

Dewatering Risers

1.6 0.9

Underground

Raisebore Aerosols Ore Moisture 2.5

Estimated Calculated or derived with some assumptions applied Measured value



Note: sum of individual items may not exactly match totals due to rounding.

Figure 3-5:

Mine water balance summary FY11 (ML/d)

3.2 Groundwater Levels 3.2.1 Background Mine dewatering and seepage from surface facilities has resulted in altered groundwater levels in both the Andamooka Limestone and Arcoona Quartzite aquifers. Standing water levels differ between the aquifers from between 1m and 15m, with the potentiometric surface being approximately 50m below the surface when unaffected by Olympic Dam’s activities. In the centre of the mine area, groundwater is constantly being depleted in both aquifers creating a cone of depression which extends for a distance of approximately 5km in the Arcoona Quartzite aquifer and approximately the same distance to the north, south and east in the Andamooka Limestone aquifer. To the west, seepage from the TSF and old mine water pond area have created a groundwater mound which has risen to a maximum height of approximately 30m below the ground surface. The low transmissivity in the limestone aquifer, limited hydrogeological interconnection to the Arcoona Quartzite aquifer and the limited number of man-made interconnections (exploration drill holes, ventilation shafts etc.) result in the mound changing very little over extended periods of time, i.e. years. Abstraction from production bore LP02 from January 2000 has reduced the groundwater mound. Commissioning approval for TSF Cell 4 requires BHP Billiton Olympic Dam to ensure that ground water levels do not rise above 80mAHD. A contingency plan nominates remedial action that can be undertaken. The groundwater has no natural surface expression in the vicinity of the Olympic Dam Mine, and is at sufficient depth as to not adversely affect the native vegetation.

3.2.2 Purpose  

Define the extent of groundwater level changes that have resulted from Olympic Dam’s activities. Maintain groundwater levels in the tailings retention area to below a level at which native vegetation could be affected.


Page 37


3.2.3 Action Trigger A trending increase in the groundwater level that indicates that 80mAHD may be exceeded within 12 months.

3.2.4 Method Groundwater levels are monitored utilising a network of exploration and groundwater monitoring bores in both the Andamooka Limestone and Arcoona Quartzite aquifers. If for some reason a groundwater level cannot be obtained (e.g. blocked bore), the nearest suitable bore will be located and monitored if appropriate. Olympic Dam will maintain sufficient monitoring bores to satisfy the requirements of the ground water model and approval MPNR98/0034 Reg 98/2639 98/2885, 6/1/99, Condition 3.

3.2.5 Results/Discussion Andamooka Limestone Aquifer Groundwater Levels Water levels in the limestone aquifer beneath the TSF (Figure 3-6) remain stable. The extent of the area with a groundwater level above 65mAHD reduced slightly from previous years. The drawdown cone on the north side of the TSF corresponding to LP02 has reduced further as a result of reduced pumping volumes from this bore (see Section 3.1.5). Groundwater levels beneath the TSF between June 2010 and June 2011 confirm these changes (Figure 3-7 and Figure 3-8). Water levels have decreased around the Quarry, where inflow into the A North Decline has resulted in localised drawdown. The maximum groundwater level recorded below the TSF for the current reporting period was 67.26mAHD at LT50 in March 2011, 0.52m higher than the maximum during the FY10 reporting period. However this measurement is uncharacteristic of the general trend of falling water levels at LT50. Trends indicate that water levels are not expected to exceed the agreed limit (TSF Cell 4) of 20m below the ground (80mAHD) within the next 12 months. Monitoring of bore LM25, located near the Olympic Dam Desalination Plant, commenced in June 2005 and following a gradual decline has remained stable over recent years. Monitoring bore LR07, located in the Roxby Downs Township, continues to report stable groundwater levels. A slight level increase is evident at LR03, near the town water storage dams. Trends at this bore will be monitored. Water levels at LM46 (Figure 3-9), located near the mine water disposal pond to the northeast of the mine area, finished the reporting period at 61.77mAHD. This is an increase from 60.64mAHD last year. Water levels increased rapidly from September 2008, due to the increase in water volume discharged into the pond from the trial mine dewatering project. Water level has been relatively stable since but recent increases in discharge appear to be resulting in a gradual water level rise. Nearby LM43 has shown near identical water level changes.

Page 38


1 JULY 2010 - 30 JUNE 2011


June 2006

June 2010

Groundwater level (mAHD)

June 2011

70

65

60

55

50

35

Datum: GDA94 Projection: MGA94 Zone: 53 Figure 3-6:

TSF area groundwater levels (mAHD) - Andamooka Limestone aquifer


Page 39


75

Groundwater level (m AHD)

70

65

60

55

45 -4000 West

-3000

-2000

-1000

0

1000

LT18

LT17

LT16

LT09

LT51

LT50

LT45

LT52

LT35

LT19

50

2000 East

Distance from centre of tailings (m from LT05) Jun-06

Jun-10

Jun-11

Note 

Monitoring bore locations shown in Figure 3-2

Figure 3-7:

Change in groundwater elevation along an east-west cross-section from LT19 to LT18, through the centre of the TSF

75 LT06 replaced by LT45 LT05 replaced by LT50


70

65

60 LT36 replaced by LT52 LT07 replaced by LT51 55

50

LT05

LT06

LT07

LT16

LT18

LT19

LT36

LT45

LT50

LT51

Jun-11

Dec-10

Jun-10

Dec-09

Jun-09

Dec-08

Jun-08

Dec-07

Jun-07

Dec-06

Jun-06

Dec-05

Jun-05

Dec-04

Jun-04

Dec-03

Jun-03

Dec-02

Jun-02

Dec-01

Jun-01

45

LT52

Note 


Figure 3-8:

Page 40

Groundwater levels for Andamooka Limestone bores in the vicinity of the TSF


1 JULY 2010 - 30 JUNE 2011


75

70


Town storage liner replaced

65

60

55

50

LR03

LR07

LM25

LM43

Jun-11

Dec-10

Jun-10

Dec-09

Jun-09

Dec-08

Jun-08

Dec-07

Jun-07

Dec-06

Jun-06

Dec-05

Jun-05

Dec-04

Jun-04

Dec-03

Jun-03

Dec-02

Jun-02

Dec-01

Jun-01

45

LM46

Note 

Monitoring bore locations shown in Figure 3-1 and Figure 3-2

Figure 3-9:

Groundwater levels for Andamooka Limestone bores in the vicinity of Roxby Downs (LR) and the Mine Water Pond (LM)

Arcoona Quartzite Aquifer Groundwater Levels An aquifer drawdown pattern is apparent in the Arcoona Quartzite due to the dewatering around the mine workings. Over previous years the gradual drawdown trend that has remained more or less constant (Figure 3-10 and Figure 3-11). During the reporting period levels have continued to drop although bores closer to the current mine workings (RD115) remain stable. RD364 was destroyed as a result of mining activities during FY06 and removed from the monitoring program. RD169, located west of RD364, exhibits a similar drawdown curve and has been shown in Figure 3-10 as a replacement, with RD364 left for comparison. RD479 was destroyed in FY09 as a result of mining activities. During the reporting period a reading was not able to be determined for RD194 due to bore integrity. RD66, located west of RD194, has been shown here as a replacement. Water level at RD115 remains stable due to its proximity to the mine and consistent drawdown patterns in that area.


Page 41

BHP BILLITON OLYMPIC DAM ENVIRONMENTAL MANAGEMENT AND MONITORING REPORT 60

40


20

0

-20

-40

-60

RD66

RD115

RD169

RD172

RD194

RD364

Jun-11

Jun-10

Jun-09

Jun-08

Jun-07

Jun-06

Jun-05

Jun-04

Jun-03

Jun-02

Jun-01

Jun-00

Jun-99

Jun-98

Jun-97

Jun-96

Jun-95

Jun-94

Jun-93

Jun-92

Jun-91

Jun-90

-80

RD479

Note 


Figure 3-10: Groundwater levels for exploration drill holes in the vicinity of the underground mine

Page 42


1 JULY 2010 - 30 JUNE 2011


June 2006

June 2010

Groundwater level (mAHD)

June 2011

60

40

20

0

-20

-40

-60

-80

Datum: GDA94 Projection: MGA94 Zone: 53 Figure 3-11: Mine area groundwater levels (mAHD) - Arcoona Quartzite aquifer


Page 43


3.3 Groundwater Quality 3.3.1 Background Groundwater in the vicinity of the operation contains water of poor quality and, as defined by ANZECC (2000), is not suitable for supporting the environmental value categories (aquatic ecosystems; recreation and aesthetics; drinking supply; primary industry). Local groundwater is also unsuitable for ore processing at Olympic Dam.

3.3.2 Purpose 

Monitor groundwater quality in the vicinity of the operations.



Quantify any possible impacts of seepage.

3.3.3 Deliverable(s) Review trends and make comparisons to ANZECC criteria.

3.3.4 Method Aquifer specific monitoring bores are pumped or bailed in order to obtain a representative groundwater sample for quality analysis. The samples are analysed for the following analytes: 

TDS, pH, calcium, chloride, copper, iron, manganese, sulphate and uranium.



In addition, samples will be analysed for the following radionuclides:



238

U, 226Ra, 230Th, 210Pb and 210Po

If for some reason a groundwater sample cannot be obtained (e.g. blocked bore), the nearest suitable bore will be located and sampled if appropriate.

3.3.5 Results/Discussion Groundwater samples were collected and subsequent analytical chemistry data was obtained for 17 groundwater monitoring bore locations in May 2011. Groundwater summary data is shown in Table 3-1. Monitoring bores sampled in May 2011 varied slightly from those detailed in BHP Billiton Olympic Dam (2010c) due to access restrictions or loss/abandonment of bores. These variations are summarised below: 

Bore LR6 was sampled instead of LR7 due to issues with high silt levels;



Bore LT21 was sampled instead of LT29 to provide a more even spacing in sampling locations;



Bore LT25 was included in the 2011 sampling event and is located in close proximity to the southwest corner of Evaporation Pond 2;



Bore LT26 was abandoned and backfilled during the Evaporation Pond 1 wall raise;



Bore LT51 was not sampled as the PVC casing in the bore has been damaged likely by construction activities in the area; and,



Bore LT61 was sampled instead of LT60 due to assess restrictions.

In the majority of bores, the salinity has remained relatively stable and within the range that could be expected for natural variation within the aquifer. The exceptions were bore LT17, which has risen from 34,000mg/L in the previous reporting period to 54,000mg/L; and, bore LM46 which has fallen from 65,000mg/L to 49,000mg/L in the current reporting period. In the majority of bores, uranium concentrations have remained relatively stable since the previous reporting period. The highest uranium concentration in the 2011 monitoring event was from bore LM46, located adjacent to the mine water pond, Page 44


1 JULY 2010 - 30 JUNE 2011


northeast of the mine (0.53mg/L), and is slightly higher than when sampled in 2010 (0.37mg/L). The uranium concentration recorded in 2011 remains less than that recorded in 2009 (0.71mg/L). Uranium concentrations of 0.48mg/L were recorded from bore LT25 in 2011. This bore is located at the southwest corner of Evaporation Pond 2. Bore LT25 was sampled for the first time in 2011 and will be included in future monitoring to confirm the elevated uranium concentration. The reported uranium concentrations in 2011 are lower than the adopted ANZECC (2000) guidelines for livestock consumption of 0.2 mg/L except at LM46 (0.53mg/L), LT25 (0.48mg/L and LT15 (0.48mg/L). The depth (approximately 40m – 50m below ground level) and the high salinity (>19,000mg/L TDS) of the local groundwater will restrict the likelihood that it would be consumed in any significant quantities, thus not posing a health hazard to people or fauna. The groundwater monitoring program continues to define the impacts of seepage in a clear and repeatable manner. The soil cover and underlying limestone rock mass continues to effectively attenuate elements present in seepage from the TSF. All analytical results are shown in Table 3-1 below. Table 3-1:

Groundwater chemistry data for bores located in the vicinity of Olympic Dam pH

Cu

U

Mn

Chloride

SO4

Ca

Fe

(mg/L)

(mg/L)

(mg/L)

(mg/L)

(mg/L)

(mg/L)

(mg/L)

2.00

0.02

0.50

N/A

500

N/A

N/A

N/A

N/A

0.50

0.20

N/A

N/A

1000

N/A

N/A

N/A

5000

LM43

May 2011