CARRAPATEENA PROJECT Environment Protection and Biodiversity Conservation Act 1999 – Referral of Proposed Action
March 2017
Carrapateena Project
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Carrapateena Project / March 2017 Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
ACKNOWLEDGEMENTS
Kokatha Aboriginal Corporation
The Kokatha People have a direct, unbroken and unique relationship with the land on which the Carrapateena Project is located.
OZ Minerals recognises that the sense of place and belonging of the Kokatha People is linked to their identity, creation stories, travel, trade, ceremonies, family and places held sacred. We recognise the deep and ongoing feelings of relationship and attachment they hold for their lands.
OZ Minerals acknowledges Kokatha connection to ‘country’, the contribution of Kokatha People to their region and the enduring importance to Kokatha People of values, cultural authority, cultural norms and customary laws.
OZ Minerals places great value on our relationship with the Kokatha People. OZ Minerals and Kokatha Aboriginal Corporation seek to work in partnership, as equals, to further develop the Partnering Agreement Nganampa palyanku kanyintjaku ‘Keeping the future good for all of us’. This collaborative agreement encapsulates, recognises and values the ongoing contribution of both partners, and will inform the relationship between Kokatha and OZ Minerals throughout and beyond the development of the Carrapateena Project.
Pernatty and Oakden Hills Station Owners
The Far North region of South Australia has a long and rich history of pastoralism. The proposed Carrapateena Project is located on Pernatty station and the proposed supporting infrastructure is located within Oakden Hills Station. OZ Minerals recognises the importance of the land to its owners and their operations and acknowledges their cooperation in developing the Project.
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DISCLAIMER a) The Environment Protection and Biodiversity Conservation (EPBC) Referral has been prepared for submission to the Australian Government Minister for the Environment and Energy under the Environment Protection and Biodiversity Conservation Act 1999, and no one other than the Minister should rely on the information contained in the EPBC Referral to make, or refrain from making, any decision. b) In preparing the EPBC Referral, OZ Minerals Carrapateena Pty Ltd and OZM Carrapateena Pty Ltd has relied on information provided by specialist consultants, government agencies and other third parties. OZ Minerals Carrapateena Pty Ltd and OZM Carrapateena Pty Ltd has not fully verified the accuracy or completeness of that information, except where expressly acknowledged in the EPBC Referral. c) The EPBC Referral has been prepared for information purposes only and, to the full extent permitted by law, OZ Minerals Carrapateena Pty Ltd and OZM Carrapateena Pty Ltd, in respect of all persons other than the Australian Government Minister for the Environment and Energy: o makes no representation and gives no warranty or undertaking, express or implied, in respect to the information contained in EPBC Referral; and o does not accept responsibility and is not liable for any loss or liability whatsoever arising as a result of any person acting, or refraining from acting, on any information contained in the EPBC Referral.
NOTE ON CURRENCY
Where possible, the contents of the EPBC Referral are up to date as at March 2017. This was not possible where parts of the EPBC Referral were prepared from information provided by third parties (as discussed in (b) above) prior to the EPBC Referral being finalised.
COPYRIGHT
Copyright © OZ Minerals Carrapateena Pty Ltd and OZM Carrapateena Pty Ltd, 2017 All rights reserved
This EPBC Referral and any related documentation is protected by copyright owned by OZ Minerals Carrapateena Pty Ltd and OZM Carrapateena Pty Ltd. Use or copying of this EPBC Referral or any related documentation, in whole or in part, without the written permission of OZ Minerals Carrapateena Pty Ltd and OZM Carrapateena Pty Ltd constitutes an infringement of its copyright.
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TABLE OF CONTENTS 1 Summary of Proposed Action ...... 1 1.1 Short Description ...... 1 1.2 Latitude and Longitude ...... 4 1.3 Locality and Property Description ...... 8 1.4 Size of the Development Footprint...... 8 1.5 Street Address of the Site ...... 8 1.6 Lot Description ...... 8 1.7 Local Government Area and Council Contact (if known)...... 12 1.8 Timeframe ...... 12 1.9 Alternatives to Proposed Action ...... 13 1.10 Alternative Timeframes ...... 13 1.11 State Assessment ...... 13 1.12 Component of Larger Action ...... 13 1.13 Related Actions/Proposals ...... 13 1.14 Australian Government Funding ...... 13 1.15 Great Barrier Reef Marine Park ...... 13 2 Detailed Description of Proposed Action ...... 15 2.1 Description of Proposed Action ...... 15 2.1.1 Proposed Project Overview ...... 15 2.1.2 Existing Activities as per Referral 2012/6494 ...... 18 2.1.3 On-Lease Resource Development ...... 19 2.1.4 Underground Mining Operations ...... 19 2.1.5 Processing Activities ...... 27 2.1.6 Tailings Storage Facility ...... 32 2.1.7 Materials Handling and Management ...... 43 2.1.8 Water Demand, Supply and Distribution ...... 48 2.1.9 Site Access and Logistics ...... 56 2.1.10 Electricity Demand, Supply and Distribution ...... 62 2.1.11 Non Process Infrastructure ...... 65 2.1.12 Closure and Rehabilitation ...... 66 2.1.13 Project Footprint Summary ...... 69 2.2 Alternatives to Taking the Proposed Action ...... 71 2.3 Alternative Locations, Time Frames or Activities That Form Part of the Referred Action ...... 71 2.4 Context, planning framework and state/local government requirements ...... 71 2.4.1 Development Plan Zoning ...... 71 2.4.2 Environmental Protection Act ...... 71 2.4.3 Radiation Protection and Control Act ...... 72 2.4.4 Native Vegetation Act ...... 72 2.4.5 Other Legislative Requirements ...... 72 2.5 Environmental Impact Assessments Under Commonwealth, State or Territory Legislation ...... 73 2.6 Public Consultation (including with Indigenous stakeholders) ...... 73 2.7 A Staged Development or Component of a Larger Project ...... 77
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3 Description of Environment and Likely Impacts ...... 79 3.1 Matters of National Environmental Significance ...... 79 3.1.1 World Heritage Properties ...... 79 3.1.2 National Heritage Places ...... 79 3.1.3 Wetlands of International Importance (Declared Ramsar Wetlands) ...... 80 3.1.4 Listed Threatened Species ...... 80 3.1.5 Listed Migratory Species ...... 89 3.1.6 Commonwealth Marine Area ...... 103 3.1.7 Commonwealth Land ...... 103 3.1.8 The Great Barrier Reef Marine Park ...... 103 3.1.9 A water resource, in relation to coal seam gas development and large coal mining development ...... 103 3.2 Nuclear actions, actions taken by the Commonwealth (or Commonwealth agency), actions taken in a Commonwealth marine area, actions taken on Commonwealth land, or actions taken in the Great Barrier Reef Marine Park ...... 104 3.2.1 Is the proposed action a nuclear action? ...... 104 3.2.2 Is the proposed action to be taken by the Commonwealth or a Commonwealth agency? .. 109 3.2.3 Is the proposed action to be taken in a Commonwealth marine area? ...... 109 3.2.4 Is the proposed action to be taken on Commonwealth land? ...... 109 3.2.5 Is the proposed action to be taken in the Great Barrier Reef Marine Park? ...... 109 3.3 Other Important Features of the Environment ...... 110 3.3.1 Flora and Fauna ...... 110 3.3.2 Hydrology and hydrogeology ...... 120 3.3.3 Air Quality...... 133 3.3.4 Soil and Vegetation Characteristics ...... 136 3.3.5 Outstanding Natural Features ...... 137 3.3.6 Remnant Native Vegetation ...... 138 3.3.7 Gradient (or depth range if action is to be taken in a marine area) ...... 138 3.3.8 Current State of the Environment ...... 138 3.3.9 Commonwealth Heritage Places or Other Places Recognised as Having Heritage Values .... 140 3.3.10 Indigenous Heritage Values ...... 140 3.3.11 Other Important or Unique Values of the Environment ...... 140 3.3.12 Tenure of the Action Area (e.g. freehold, leasehold) ...... 141 3.3.13 Existing Land/Marine Uses of Area ...... 141 3.3.14 Any Proposed Land/Marine Uses of Area ...... 141 4 Environmental Outcomes ...... 143 5 Measures to Avoid or Reduce Impacts...... 145 6 Conclusion on the Likelihood of Significant Impacts ...... 149 6.1 Do you THINK your proposed action is a controlled action? ...... 149 6.2 Proposed action IS NOT a controlled action ...... 149 7 Environmental Record of the Responsible Party ...... 151 8 Information Sources and Attachments ...... 153 8.1 References ...... 153 8.2 Reliability and Date of Information ...... 157
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8.3 Attachments ...... 157 9 Contacts, signatures and declarations ...... 159 10 Appendices ...... 161
List of Appendices
Appendix 1 EPBC Act Protected Matters Report
Appendix 2 Ecological Baseline Assessment
Appendix 3 Ecological Impact Assessment
Appendix 4 Environmental and Public Radiation Impact Assessment
Appendix 5 Occupational Radiation Assessment
List of Figures
Figure 1.1: Project Location ...... 2 Figure 1.2: Proposed Tenements and Key Project Elements ...... 3 Figure 1.3: Proposed Tenements Latitude and Longitude Coordinates ...... 7 Figure 1.4: Land Ownership and Pastoral Homesteads ...... 10 Figure 1.5: Proposed OZ Minerals Tenements and Underlying Exploration Licences ...... 11 Figure 2.1: Proposed Mining Lease and Key Project Elements ...... 17 Figure 2.2: Conceptual Sub-Level Caving Mining Method ...... 21 Figure 2.3: Estimated Sub-level Cave Zone of Influence ...... 22 Figure 2.4: Conceptual Underground Mining (Tjati) Decline and Ventilation Cross-section ...... 26 Figure 2.5: Conceptual Processing Plant Layout ...... 29 Figure 2.6: Indicative Ore Processing Schematic Flowsheet ...... 30 Figure 2.7: Cross-Section of Tailing Storage Facility ...... 35 Figure 2.8: TSF Decant Cross-section ...... 38 Figure 2.9: TSF Embankment Cross-section ...... 41 Figure 2.10: Material Movement Balance ...... 45 Figure 2.11: Subsidence Zone Quarry Conceptual Layout and Cross Section ...... 46 Figure 2.12: Western Infrastructure Corridor Borrow Pits Conceptual Layout and Cross Section ...... 47 Figure 2.13: Installed Groundwater Supply Network and Conceptual Project Wellfield ...... 50 Figure 2.14: Indicative Water Balance ...... 52 Figure 2.15: Conceptual Surface Water Management System ...... 55 Figure 2.16: Site Access and Logistics Layout ...... 57 Figure 2.17: Indicative Western Access Road and Electrical Infrastructure Alignments ...... 63 Figure 2.18: Pre and Post Carrapateena Project Cross Sections ...... 68 Figure 2.19: Mining Act Two-Stage Assessment Process ...... 75 Figure 3.1: Plains Mouse Habitat Mapping, Proposed Tenements and Key Project Elements ...... 87 Figure 3.2: Vegetation Association and Land Disturbance Comparison ...... 112 Figure 3.3: Surface Water Catchment and Primary Infrastructure Components ...... 126 Figure 3.4: Conceptual Hydrogeological Model, Pre-mining ...... 132 Figure 5.1: Hierarchy of Controls ...... 146
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List of Tables
Table 1.1: Proposed Tenements and Key Project Elements ...... 1 Table 1.2: Proposed Tenements Latitude and Longitude Coordinates ...... 4 Table 1.3: Proposed Tenements and Location of Land ...... 9 Table 1.4: Carrapateena Conceptual Project Schedule ...... 12 Table 2.1: Proposed Carrapateena Project Key Project Elements ...... 15 Table 2.2: Existing Retention Lease Key Project Elements...... 18 Table 2.3: Mining Infrastructure ...... 24 Table 2.4: Ore Processing ...... 27 Table 2.5: TSF Design Characteristics Summary ...... 32 Table 2.6: Summary of Tailings Production by TSF Development Stage ...... 34 Table 2.7: Indicative TSF Water Balance ...... 36 Table 2.8: TSF Water Management ...... 36 Table 2.9: TSF Starter (Stage 1) Embankment Properties ...... 39 Table 2.10: TSF Embankment Properties ...... 39 Table 2.11: Construction Material ...... 43 Table 2.12: Water Demand ...... 48 Table 2.13: Indicative Carrapateena Water Demand ...... 48 Table 2.14: Water Supply ...... 49 Table 2.15: Water Treatment and Distribution ...... 51 Table 2.16: Surface Water Holding Ponds ...... 54 Table 2.17: Site Access and Logistics ...... 56 Table 2.18: Waterway crossings ...... 60 Table 2.19: Key Design Criteria and Characteristics of the Transmission Line ...... 62 Table 2.20: Non Process Infrastructure Key Project Elements ...... 65 Table 2.21: Closure and Rehabilitation ...... 66 Table 2.22: Existing, Scheduled and Proposed Project Footprint ...... 69 Table 2.23: Project Stakeholders ...... 73 Table 2.24: Existing Tenements, Proposed Tenements and Potential Future Tenements ...... 77 Table 3.1: Results from MNES Search Proposed Tenements ...... 79 Table 3.2: Threatened Species Identified by EPBC Protected Matters Search Tool or in Ecological Surveys ...... 81 Table 3.3: Migratory Species Identified by the EPBC PMST or in Ecological Surveys ...... 89 Table 3.4: Marine Species Identified by the EPBC Protected Matters Search Tool or in Ecological Surveys ...... 97 Table 3.5: Estimated Radionuclide Composition of Process Streams ...... 104 Table 3.6: Public Total Dose Estimates ...... 107 Table 3.7: Summary of Radiation Impacts during the Proposed Project ...... 109 Table 3.8: Project Area Vegetation Associations ...... 111 Table 3.9: Flora Species Diversity, Abundance, Cover and Threatened Species ...... 113 Table 3.10: Carrapateena State Conservation Significant Flora Species ...... 114 Table 3.11: Species Diversity, Abundance, and Threatened and Pest Species ...... 116 Table 3.12: Carrapateena State Conservation Significant Fauna Species ...... 117 Table 3.13: Surface Water Catchment and Project Elements ...... 120 Table 3.14: Summary of Baseline Air Quality Monitoring ...... 133 Table 3.15: Summary of Baseline Environmental Radiation Monitoring ...... 133 Table 3.16: Bioregion, Sub-region, and Environmental Association Environmental Landscape Summary ...... 136 Table 3.17: Project Area Recorded Pest Plant and Weed Species ...... 138 Table 3.18: Project Area Recorded Pest and Feral Animal Species ...... 139
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Table 5.1: Summary of Design Controls...... 147 Table 5.2: Summary of Management Controls ...... 148 Table 7.1: Environmental Record and Management Capabilities ...... 151 Table 8.1: Attachments ...... 157 Table 9.1: Person Proposing to Take the Action ...... 159
List of Plates
Plate 2.1: Site Access and Logistics: Roads ...... 58 Plate 2.2: Site Access and Logistics: Rail ...... 59 Plate 2.3: Examples of Waterway Crossings ...... 61 Plate 2.4: Indicative Electricity Infrastructure ...... 64
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1 SUMMARY OF PROPOSED ACTION
1.1 Short Description
OZ Minerals Carrapateena Pty Ltd and OZM Carrapateena Pty Ltd (collectively referred to as OZ Minerals) are proposing to develop the Carrapateena Project (Project) located approximately 160 km north of Port Augusta (see Figure 1.1). The Project will produce a high quality copper-gold concentrate through underground sub-level cave (SLC) and sub-level open stope (SLOS) mining and ore processing. Ore from underground will be processed at a nominal rate of approximately 4 Mtpa (with environmental assessments undertaken on 4.8 Mtpa) via a conventional crushing, grinding and flotation circuit, followed by a pressure leach hydrometallurgical operation, referred to as the Concentrate Treatment Plant (CTP), designed to increase the grade of the concentrate. Concentrate will be produced at a rate of up to approximately 175,000 dry tpa and will be exported to customers both in Australia and overseas.
OZ Minerals intends to submit a Mining Lease Proposal and associated Miscellaneous Purposes Licence Management Plans (collectively referred to as the MLP) under the provisions of the South Australian Mining Act 1971 (SA) (Mining Act) to support applications for a Mining Lease and three Miscellaneous Purposes Licences (MPL). These are for the purposes of constructing and operating the key Project elements described in Table 1.1 and shown on Figure 1.2. The single approval submission is structured to enable an assessment of the Carrapateena Project for the granting of a mining tenement and multiple supporting infrastructure tenements as listed in Table 1.1. Current activities on the site include advanced exploration work being undertaken under a Retention Lease (RL) authorised under the Mining Act. The RL was granted for the purpose of undertaking further geotechnical investigations in order to inform the selection of an appropriate and cost-effective mining method for the resource (OZ Minerals, 2015). The Tjati Decline development commenced in September 2016, and the results of the Pre-Feasibility Study (PFS), including further geotechnical analysis, were announced on 7 November 2016. The Advanced Exploration Works were deemed not a controlled action under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) on 30 August 2012 (EPBC reference 2012/6494).
Table 1.1: Proposed Tenements and Key Project Elements
Proposed Tenement Key Project Elements
Mining Lease
Mining, processing, tailings storage facility, water supply Carrapateena Mining Lease and ancillary infrastructure
Miscellaneous Purposes Licences
Eastern Radial Wellfield MPL Water supply (east)
Southern Access Road and Radial Wellfield MPL Access road and water supply (south)
Western Infrastructure Corridor MPL Transmission line, access road and common services
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Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
1.2 Latitude and Longitude
The latitude and longitude coordinates for the proposed tenements are shown in Table 1.2 and Figure 1.3.
Table 1.2: Proposed Tenements Latitude and Longitude Coordinates Latitude Longitude Area Description Degrees Minutes Seconds Degrees Minutes Seconds 1 -31 10 57.0 137 32 19.0 2 -31 12 57.5 137 32 19.0 3 -31 12 57.5 137 31 44.4 4 -31 13 58.9 137 31 44.4 5 -31 14 7.0 137 33 39.6 6 -31 12 35.8 137 35 24.7 7 -31 12 35.8 137 35 31.6 8 -31 13 3.2 137 35 31.6 9 -31 14 38.9 137 34 26.1 10 -31 16 6.0 137 33 53.2 11 -31 17 5.0 137 33 16.1 12 -31 18 59.7 137 32 32.4 13 -31 18 59.7 137 31 44.4 14 -31 19 35.8 137 31 44.4 15 -31 19 35.8 137 31 19.7 16 -31 23 20.6 137 31 19.7 17 -31 23 20.6 137 30 26.4 18 -31 23 35.8 137 30 25.0 19 -31 23 44.5 137 30 31.8 20 -31 23 59.3 137 30 30.5 21 -31 24 8.0 137 30 21.9 22 -31 24 46.1 137 30 8.6 23 -31 25 9.4 137 30 4.7 24 -31 25 46.4 137 30 1.0 25 -31 26 53.8 137 29 54.5 26 -31 27 39.4 137 29 40.1 27 -31 29 2.3 137 30 2.2 28 -31 30 39.2 137 29 4.1 29 -31 30 22.3 137 29 4.9 30 -31 29 50.1 137 29 8.5 31 -31 29 22.4 137 29 0.2 32 -31 29 14.5 137 28 57.6 33 -31 29 3.0 137 28 50.4 34 -31 29 1.3 137 28 51.0 35 -31 28 53.5 137 28 54.4 36 -31 28 50.7 137 28 45.5
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Latitude Longitude Area Description Degrees Minutes Seconds Degrees Minutes Seconds 37 -31 28 58.5 137 28 42.2 38 -31 29 5.7 137 28 41.5 39 -31 29 16.8 137 28 48.4 40 -31 29 25.2 137 28 51.3 41 -31 29 52.0 137 28 59.2 42 -31 30 22.5 137 28 55.5 43 -31 30 36.5 137 28 55.1 44 -31 30 55.4 137 28 42.6 45 -31 30 33.8 137 28 35.9 46 -31 27 43.3 137 27 44.8 47 -31 26 53.1 137 29 44.9 48 -31 26 46.6 137 29 47.0 49 -31 25 12.0 137 29 55.5 50 -31 24 44.6 137 29 59.3 51 -31 24 4.0 137 30 13.4 52 -31 23 56.0 137 30 21.3 53 -31 23 46.7 137 30 22.1 54 -31 23 38.0 137 30 15.4 55 -31 23 25.3 137 30 16.5 56 -31 23 20.6 137 30 17.0 57 -31 23 20.6 137 29 41.3 58 -31 21 2.8 137 29 41.3 59 -31 21 2.7 137 28 58.5 60 -31 21 3.1 137 23 16.6 61 -31 22 53.5 137 21 21.0 62 -31 21 19.2 137 15 29.7 63 -31 21 14.8 137 14 21.8 64 -31 24 58.0 137 10 5.4 65 -31 24 57.9 137 9 55.4 66 -31 25 6.8 137 9 55.3 67 -31 26 16.2 137 8 35.5 68 -31 26 12.9 137 7 50.9 69 -31 26 57.3 137 7 47.5 70 -31 28 33.4 137 5 58.3 71 -31 28 34.2 137 5 57.3 72 -31 29 12.9 137 5 12.9 73 -31 28 59.8 137 5 2.1 74 -31 28 55.9 137 4 58.2 75 -31 28 52.4 137 4 53.3 76 -31 28 49.7 137 4 47.8 77 -31 28 42.7 137 4 29.9
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Latitude Longitude Area Description Degrees Minutes Seconds Degrees Minutes Seconds 78 -31 28 39.5 137 4 21.6 79 -31 28 8.0 137 3 1.5 80 -31 28 5.9 137 2 57.1 81 -31 27 25.0 137 4 37.3 82 -31 26 18.6 137 5 54.2 83 -31 26 34.5 137 6 18.6 84 -31 25 55.9 137 7 4.8 85 -31 25 22.5 137 6 58.1 86 -31 23 17.1 137 9 22.0 87 -31 18 49.1 137 11 14.5 88 -31 19 51.2 137 13 19.2 89 -31 20 22.5 137 15 36.7 90 -31 19 58.3 137 21 52.6 91 -31 19 33.1 137 22 29.0 92 -31 17 52.3 137 23 29.3 93 -31 15 31.7 137 27 11.3 94 -31 14 52.5 137 28 14.3 95 -31 12 8.9 137 28 14.3 96 -31 12 8.9 137 29 35.9 97 -31 10 57.0 137 29 35.9
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Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
1.3 Locality and Property Description
The Project is located approximately 500 km north of Adelaide, South Australia on the eastern margin of the Gawler Craton. It is located approximately 160 km north of Port Augusta. Nearby townships include Woomera (approximately 65 km west) and Roxby Downs (approximately 90 km north-west). Property descriptions are provided in Section 1.6 and the location of the Project is shown in Figure 1.1.
1.4 Size of the Development Footprint
The Project will require the clearing of land for the establishment of Project infrastructure, with a footprint of approximately 2,924 ha (including buffers), of which approximately 1,790 ha will be rehabilitated at closure.
1.5 Street Address of the Site
The location does not have an associated street address. For lot description details, see Section 1.6.
1.6 Lot Description
The proposed tenements lie within the Pernatty and Oakden Hills Pastoral Leases, which share boundaries with Bosworth, Arcoona and South Gap Pastoral Leases (see Table 1.3 and Figure 1.4).
The Western Infrastructure Corridor also intersects a freehold parcel of land owned by WMC (Olympic Dam Corp) Pty Ltd. The parcel contains a transmission line that connects the Olympic Dam mine to the Davenport substation, located near Port Augusta.
The area within which the tenements are proposed is subject to the Kokatha People (Part A) Native Title Determination (Tribunal Reference SCD2014/004) as shown in Figure 1.4. The Kokatha Aboriginal Corporation (KAC) is the Registered Native Title Body Corporate who acts as an agent for the Kokatha People in relation to their native title rights and interests.
In addition, OZ Minerals maintains a number of existing tenements, including the Carrapateena Retention Lease (RL 127) and Exploration Licences. The proposed tenements also overlap with other third-party land interests as illustrated in Figure 1.5.
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Table 1.3: Proposed Tenements and Location of Land
Proposed Tenement Purpose Location of land Mining Lease Mining, processing, tailings Pernatty Pastoral Lease. Crown Ref: storage facility (TSF), on-site PE002353 power generation, water supply, Plan/Parcel D47706Q Piece 2 ancillary infrastructure Hundred: OH (Torrens) Crown Lease Volume 1330 Folio 26 Eastern Radial Wellfield Water supply (east) Pernatty Pastoral Lease. Pastoral block: MPL PE2353 Section: H834600 Block 868 OH; D47706Q Piece 2 Hundred: OH (TORRENS) Crown Lease Volume 1330 Folio 26 Southern Access Road and Access road, Pernatty Pastoral Lease. Pastoral block: Radial Wellfield MPL water supply (south) PE2353 Section: H834600 Block 868 OH; D47706Q Piece 2 Hundred: OH (Torrens) Crown Lease Volume 1330 Folio 26 Western Infrastructure Transmission line, access road, Pernatty Pastoral Lease. Crown Ref: Corridor MPL common services PE002353 Plan/Parcel D47706Q Piece 2 Hundred: OH (Torrens) Crown Lease Volume 1330 Folio 26 Oakden Hills Pastoral Lease. Crown Ref: PE002377 Plan/Parcel D47746Q Piece 2 Hundred: OH (Torrens) Crown Lease Volume 6178 Folio 725 Certificate of Title 6135/25 – WMC (Olympic Dam Corp) Pty Ltd Plan/Parcel: D47746AL109 Hundred: OH (Torrens) Crown Lease Volume 1330 Folio 26
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ELA 2016/00026
Adelaide Lake Hanson
EL 5729
Lake Hart GEL 294 St uart Lake Torrens Hig EL 5919 hw Woomera ay PELA 601
Lake Windabout Proposed Mining Lease / Carrapateena ELA Retention Lease 2016/00162 EL 5768 GEL 295 Proposed OZ Minerals Tenements OZ Minerals Carrapateena Pty Ltd Geothermal Exploration Licence Island Lagoon EL 5636 Petroleum Exploration Licence Application ELA Mineral Exploration Licence Application 2016/00026 Copper Range (SA) Pty Ltd Pernatty OZM Carrapateena Pty Ltd; OZ Minerals Lagoon Carrapateena Pty Ltd Mineral Exploration Licence OZ Minerals Carrapateena Pty Ltd Exploration Licence GCS GDA 1994 Copper Range (SA) Pty Ltd 1:675,000GCS GDA@ 1994 A4 Monax Mining Limited Lake 015 020 Lake Finniss MacFarlane Terrace Mining Pty Ltd Kilometres
Figure 1.5: Proposed OZ Minerals Tenements and Underlying Exploration Licences
CARRAPATEENA PROJECT Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
1.7 Local Government Area and Council Contact (if known)
The area comprising the proposed tenements is zoned as Remote Area (Far North) in the Development Plan – Land Not within a Council Area Eyre, Far North, Riverland and Whyalla, which is under the jurisdiction of the Outback Communities Authority. OZ Mineral’s primary contact for the Outback Communities Authority is provided below:
Cecilia Woolford Chair Outback Communities Authority Phone: 08 8648 5970 In addition, activities undertaken for the Project are done so in consultation with the Mayor of Port Augusta where necessary. Details are below:
Sam Johnson Mayor of Port Augusta Phone: 08 8641 9100 Email: [email protected]
1.8 Timeframe
The Project has an operational life of approximately 20 (up to 27) years of ore production (2019 – 2039) plus decommissioning and closure. The high-level Project schedule for the proposed Carrapateena operation is summarised in Table 1.4. Due to the nature of the Project, the schedule and timing of activities may alter as it develops.
Table 1.4: Carrapateena Conceptual Project Schedule
Project Phases 2016 2017 2018 2019 2020 2039 2042 2049 Regulatory Approvals and
Land Access
Construction
Operations
Progressive
Rehabilitation Decommissioning, Closure and Rehabilitation Long-term Closure
Activities and Monitoring
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1.9 Alternatives to Proposed Action
Yes. OZ Minerals has undertaken detailed studies during the PFS that have explored alternative mining methods, processing activities and tailings disposal options. The alternatives considered during the PFS and the basis of design are discussed further in Section 2.3.
1.10 Alternative Timeframes
No alternative timeframes are proposed.
1.11 State Assessment
The State assessment process is outlined in Section 2.5.
1.12 Component of Larger Action
The larger action is described in Section 2.7.
1.13 Related Actions/Proposals
Current activities on the site include advanced exploration work being undertaken under a Retention Lease (RL 127). The RL was granted for the purpose of undertaking further geotechnical investigations in order to inform the selection of an appropriate and cost-effective mining method for the resource. The associated Carrapateena Advanced Exploration Works were referred in 2012 and determined not to be a controlled action (2012/6494). The scope of the EPBC referral for the Advanced Exploration Works included an Airstrip, Accommodation Village and Associated Infrastructure, and a Management Plan to support the application for a Miscellaneous Purposes Licence has been submitted to the State of South Australia for consideration.
1.14 Australian Government Funding
No Australian Government grant funding has been received for this project.
1.15 Great Barrier Reef Marine Park
The Great Barrier Reef Marine Park is over 2000 km away.
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2 DETAILED DESCRIPTION OF PROPOSED ACTION
2.1 Description of Proposed Action
2.1.1 Proposed Project Overview
The Carrapateena Project proposes to extract ore from an underground SLC mine and process the ore to produce a high quality copper/gold concentrate for export to customers both in Australia and overseas. The key Project elements described throughout this document are illustrated in Figure 1.2 and summarised in Table 2.1. Key elements within the proposed Mining Lease are shown in Figure 2.1. For the purposes of determining the potential impacts of the Project, the key Project elements (sources) and their inputs and outputs have been used to inform the studies undertaken where they interact with the environment.
Table 2.1: Proposed Carrapateena Project Key Project Elements
Proposed Tenement Key Project Elements
Mining Method Sub-level caving (SLC) with potential for future sub-level open stoping (SLOS) of satellite deposits. Primary Access Tjati Decline, consisting of two parallel access drives supported by independent boxcuts and portals (Approved under RL 127) Mining Rate 4.0 Mtpa (with environmental assessments undertaken on 4.8 Mtpa)
Mine Life 20 years of ore production (2019 – 2039) at a nominal 4.0 Mtpa (scalable to 27 years of ore production plus decommissioning and closure). Commodities Copper, gold, silver
Processing Conventional copper concentration processing plant, 500 tph, 1.78% Cu and 0.71 g/t Au average life of mine (LOM) feed grade, 2.50% Cu design feed grade, 91.4% Cu and 73.4% Au average LOM recovery. Tailings Storage Facility Cross-valley embankment, 145 Mt, 2.7 – 4.7 Mtpa supply rate, solids concentration of 65%, with capacity for up to 34 years of tailings deposition life at an average of 4.3 Mtpa, rate of rise initially up to 6.5 m/y, decreasing to approximately 1 m/y at Year 4 and 0.5 m/y at Year 20. Power Demand 410 GWh/y with a daily demand of up to 57.5 MW, supplied from a 132 kV electricity transmission line connection to the SA electricity grid, supplemented with on-site renewable and diesel generation. Water Demand Construction: up to 2.5 ML/d. Operations: 8 – 13 ML/d, mixed quality required to meet construction and operational constraints. Water Supply and Construction water supply will be provided by a radial wellfield, supplemented as Distribution operations commence by possible future Regional Project Wellfield, providing a staged approach to water supply. Blending of differing water qualities to meet construction and operational constraints. Additional water supply sourced from tailings decant water reclaim (up to 1.3 ML/d) and/or mine dewatering reclaim (up to 4 – 9 ML/d). Water-holding and distribution network including ponds/dam, piping, pumps and an independent power supply. Workforce Operational workforce of approximately 450 people.
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Proposed Tenement Key Project Elements
Construction Material A quartzite quarry in the planned subsidence zone to provide early access to Quarrying construction materials for use in the development of infrastructure. TSF construction borrow pits developed to support embankment construction. Borrow pits will be established under proposed future Extractive Minerals Leases (EMLs) along the Western Infrastructure Corridor to provide construction materials for the Site Access Road. Surface Infrastructure Centrally-located service facilities to support operations, including mine ventilation infrastructure, offices, workshops and administration facilities, refuelling infrastructure, stockpile and hardstand areas and explosives magazines. Transmission Line Transmission line to connect to South Australian electricity network at Mt Gunson. Route will be contained within the Western Infrastructure Corridor. The transmission line design is based on the use of steel poles of approximately 26 m height on a spacing of 250 m. Rail Siding A number of options are being examined for a potential rail siding. A potential future rail siding may be established in proximity to the existing Wirrappa Siding for the import and export of concentrate materials and reagents. This may include a dedicated private haul road of approximately 10 km linking the siding to the western end of the Site Access Road. Southern Access Road Existing southern access road, with access to the site via a gazetted road that connects the RL boundary to the Stuart Highway. Maintained and managed in accordance with a Deed signed by both OZ Minerals and the South Australian Department of Transport, Planning and Infrastructure. Western Access Road Future access to and from site via a dedicated Site Access Road in the Western Infrastructure Corridor, leaving the western boundary of the Mining Lease to intercept Stuart Highway at an upgraded intersection located close to Mt Gunson, approximately 52 km south-east of Pimba by road.
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2.1.2 Existing Activities as per Referral 2012/6494
This section summarises activities that are currently being undertaken under RL127 for Advanced Exploration Works. This activity was subject to an EPBC Act referral (EPBC 2012/6494) in which it was determined not to be a controlled action. The RL was granted for undertaking further geotechnical investigations in order to inform the selection of an appropriate and cost-effective mining methodology for the resource. The Tjati Decline development commenced in September 2016, and the results of PFS work, including further geotechnical analysis, were announced on 7 November 2016. Table 2.2 summarises the existing RL key Project elements.
Table 2.2: Existing Retention Lease Key Project Elements
Key Project Element Summary
Tjati Decline A decline consisting of two parallel access drives supported by independent boxcuts and portals and associated underground development to 750 mBGL. Ventilation Ventilation raises, fans and associated infrastructure.
Exploration Activities and Drilling programs using techniques such as diamond drilling, RC and PCD mud Resource Development rotary. Geophysical surveys including gravity, ground magnetics, induced polarity and seismic techniques to further define regional anomalies. Offices, Workshops and Administration buildings for contractors and OZ Minerals, common facilities Village including bath house, ablutions, muster room, cap lamp room, laundry, crib rooms, bus/car parking, outdoor lighting, decks, walkways and roads, workshops and stores. Bulk fuel storage facilities – a series of self-bunded tanks (50,000 L to 150,000 L) with a combined storage capacity between 50,000 L to 1 ML and associated concrete slabs, bowser/discharge hosing, lighting and pumps. Explosive Storage Current licensed magazine and storage impoundments incorporating fencing, lockable gates, specially designed and fabricated explosives magazines, dedicated access roads, appropriate signage and other incidentals. Waste Rock Landform Approximately 0.7 Mt of waste rock material stockpiled in a surface Waste Rock Landform (WRL), the capacity of the WRL is up to 1.4 Mt of NAF and PAF. Water Exploration, Production wells up to the installed capacity of 5 ML/day. Supply and Distribution Injection wells for disposal of reverse osmosis reject water. Underground dewatering infrastructure. Site Access and Road Access to the site is via a gazetted road that connects to the Stuart Highway. The Network maintenance and development of the road is managed in accordance with a Deed. Site roads are developed within the agreed disturbance footprint and some roads are subject to agreements with local pastoralists. Airstrip and Terminal Sealed 1,880 m long airstrip suitable for use by an ATR-600 (or similar) aircraft and Facilities capable of carrying up to 50 passengers. 30 m wide runway running surface. The runway running surface would be contained within a 90 m wide cleared and graded strip area. Accommodation Facilities A workforce of approximately 160 people is required to construct the decline and carry out the underground geotechnical and exploration programs. They are accommodated in a village that accommodates up to 176 people.
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2.1.3 On-Lease Resource Development
In early 2013, OZ Minerals announced an updated mineral resource for the Carrapateena deposit, totalling 760 Mt of indicated and inferred mineral resource. This was subsequently updated in November 2013 to 800 Mt at 0.8% copper and 0.3 g/t gold for 6.3 Mt copper and 8.4 Moz of gold. A high-grade mineral resource of 61 Mt within the broader 800 Mt was identified and announced to market in October 2015 based on using SLOS mining methods. On 7 November 2016, OZ Minerals restated the 2015 Mineral Resource (as at 17 October 2016) based on an SLC mining methodology at 133 Mt (see Section 2.1.4), and an updated Ore Reserve Estimate of 70 Mt. The Mineral Resource was subsequently revised to 134 Mt in December 2016 reflecting increased confidence in the Mineral Resource Estimate. Therefore, there remains significant mineral resources surrounding the proposed SLC operation, with the potential to extend the life of the mine and/or increase the rate of ore production.
Outside the greater mineral resource footprint, there are a number of satellite prospects that may be further drilled and delineated in future. The Fremantle Doctor anomaly is located approximately 2.5 km north-east of Carrapateena and is interpreted to be associated with the Carrapateena mineral resource. Drilling results to date have intercepted more than 1 km of mineralisation, including approximately 577 m of higher-grade material. Mineralisation has also been intercepted at the Saddle prospect, located between Fremantle Doctor and Carrapateena.
Due to the proximity of these satellite deposits to the Carrapateena mining operations, and the subsequent potential to access these from the proposed underground mining operations, the proposed ML boundary has been aligned to place these deposits within the ML.
It is expected that further drilling into the Carrapateena orebody and potential works to further define and delineate the Saddle and Fremantle Doctor deposits would be completed from either underground and/or at surface.
2.1.4 Underground Mining Operations
The Carrapateena mineralisation forms a relatively massive resource suitable to a bulk mining method. A number of studies preceding the current PFS evaluated the potential for an open pit mining operation together with the three commonly used underground bulk mining methods of block caving, SLOS and SLC. It is proposed to use SLC techniques for the high-grade mineral resource with SLOS utilised for the extraction of minerals from satellite deposits.
Sub-Level Caving In SLC mining, mining starts at the top of the orebody and develops downwards, with ore extracted from sub-levels spaced at nominally 25 m intervals throughout the deposit. A series of ring patterns are drilled and blasted from each sub-level and broken ore is extracted after each blast (see Figure 2.2). In some cases, additional assistance (called pre-conditioning) is required to initiate the caving process in areas above the orebody. The requirement for pre-conditioning and suitable methods are the subject of intensive study and geotechnical evaluation. Large-scale pre-conditioning is not expected to be required at
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Carrapateena. However, should it be required, a decision would be made early in the mine life to avoid potential long-term issues with cave propagation.
During the first two years of mining operations, while construction of the Tjati Decline conveyor and underground crushing systems are progressing, a load haul dump (LHD) loader would transfer the ore into haul trucks, where it would be transferred to a surface stockpile prior to surface crushing. After the installation of the Tjati Decline conveyor and crusher systems, ore would be collected in an LHD loader and delivered directly to an ore pass that would subsequently feed an underground crusher. Crushed ore would be conveyed to the surface coarse ore stockpile (COS) via the Tjati Decline conveyor system prior to processing.
Waste rock generated during mine development would preferentially be backfilled to underground voids where available (e.g. disused development drives etc.), or would otherwise be trucked or conveyed to the surface for use as a construction medium or stockpiled in a suitable manner on the Waste Rock Stockpile (WRS) (see Section 2.1.7).
The area above the cave would consist of a subsidence zone (approximately 800 m in diameter) surrounded by a zone of fracturing (approximately 200 m wide). Together, the crater/subsidence zone and the fracture zone are referred to as the zone of influence. Figure 2.3 presents the final extent of the predicted zone of influence. The fracture zone would grow progressively, with progression slowing to the final extent as the mine deepens. It is expected that by approximately 2030, the fracture zone would be 80–90% developed.
Water ingress to the mine would be via the fractures and crater. It is likely that the cave would breach the Tent Hill Aquifer (THA) in 2021–2022. The breach would have an initial diameter of about 150 m, extending to approximately 800 m including the fracture zone. The mine dewatering system is discussed in Table 2.3.
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Sub-Level Open Stoping SLOS remains a viable option for the extraction of ore on the peripheral of the sub-level cave and satellite parcels of higher-grade ore within the greater deposit footprint, such as Fremantle Doctor. For areas of the greater resource that are mined using SLOS, sub-levels would be developed and extend horizontally across the length of the orebody. Funnel-shaped drawpoints would be established at the base (footwall) of the stopes to allow for extraction of blasted ore, and an orepass would be developed which allows the LHD mobile fleet to collect ore from drawpoints and transfer it to trucks for haulage to the surface stockpiles via the Tjati Decline, or sent to the crushing and conveying system.
The level found above the drawpoints would be the first to be mined. A slot would be driven either along one side of the stope, or in the middle to allow the ore to swell when broken. The initial drilling would be right beside the slot and would retreat towards the level access or edge of the orebody. As the lowest level starts to retreat, the level above it can be drilled and blasted. This repeats for each successive level above.
The deposits may be divided into many stopes, all following the basic process outlined above. This allows for the simultaneous mining of different areas of deposit, thereby increasing production rates.
Satellite deposits mined using SLOS may be filled with paste or another type of cemented fill or uncemented waste rock from the mine. Alternatively the stopes may be left open if this presents no geotechnical or ore sterilisation risk.
Mining Infrastructure A number of key elements exist to enable effective and efficient mining, as described in Table 2.3.
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Table 2.3: Mining Infrastructure
Key Project Element Summary
Ground Control The north face of the boxcut containing the portal will be supported by cable bolts and fibrecrete. The boxcut may be fitted with an Armco tunnel structure. All underground development will be supported with fibrecrete and rock bolts. Some short life development may be supported with mesh and rock bolts. Cable bolts are installed where necessary. Fibrecrete would be manufactured using an on-site fibrecrete batch plant. Fresh Arcoona quartzite from the lower section of the boxcut and the decline will be separately stockpiled for this purpose. The material will be crushed by portable crushers to produce the required aggregate grading sizes. When the fresh Arcoona quartzite material is exhausted, selective mine development waste from the basement rocks would be used for the construction of fibrecrete. Mine Dewatering Mining activities extend below the water table. Groundwater inflows are expected to occur into the underground workings. A groundwater exploration well installed at the Tjati Decline intersect point of the most permeable hydrostratigraphic unit (i.e. THA) suggested low hydraulic conductivities within that particular location of the aquifer (i.e. at yields too low for advanced depressurisation, airlift drilling yield of <1 L/s). It is intended that water inflows at the THA intersect would be managed and removed via the Tjati Decline, rather than through well installation. A dewatering system within the underground operation would capture the remaining inflow water in sumps before pumping to the surface mine water settling ponds. This water is expected to be able to meet the entirety of the underground mine operational water demand. Groundwater modelling predictions (see Section 3.3.2) estimate inflows to be approximately 4 ML/d over the life of mine. It is expected that inflows would decrease during operations. An alternative method of managing inflows to the underground operations being assessed by OZ Minerals is to install depressurisation/dewatering wells within the vicinity of the SLC. Ventilation All underground workings require ventilation to ensure clean air is provided and contaminants (e.g. dust, diesel particulates and radon) are removed. The proposed SLC ventilation system is based on the specific requirements of the mine (see Figure 2.4). The mine may be ventilated by a positive pressure-type ventilation system for production areas and a negative pressure-type (exhausting) ventilation system for early access development and conveyor and crusher infrastructure. The primary intake raises are located in a cluster outside of the zone of influence, with the bottom of the raises at 4,585 mRL. The primary exhaust raises are located in a separate cluster with the bottom of the raises at 4,630 mRL, as shown in Figure 2.4. These shafts would be a combination of 3.0, 4.5 and 5.0 m in diameter. Exhaust raises would exhaust vertically at the surface. Ventilation is the most significant radiation protection measure for workers during underground mining. An adequate quantity of fresh air must be supplied to the commencement of the drives, and as such, the ventilation system has been designed to provide sufficient airflow in all drives, which will vary with drive size. Any recirculation of exhaust air would lead to a rapid increase in radon decay product (RnDP) concentrations in working areas, so the ventilation system would be a single pass, with no re-use of ventilation air. Should circumstances result in elevated RnDP concentrations (for example, a ventilation fan failure), then access would be restricted and respiratory protection would be used as a temporary expedient while the situation is being remedied (normal particulate filtration is effective for RnDPs). A hierarchy of controls will be in place for elevated radon, depending on the concentration.
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Key Project Element Summary
Refrigeration For the proposed Carrapateena underground operations, no refrigeration of the incoming air is required for depths less than approximately 900 m below ground level, and as such, no air refrigeration systems are initially proposed. Further development beyond the 900 m depth is likely to require the installation of a surface refrigeration plant. Transportable air refrigeration units may be used for spot cooling of specific underground development faces as necessary. Crushers Two nominal 1,000 tph underground gyratory crushers would be installed within the mine, one at mid-orebody height to be used during the initial underground ore production activities, and one near the base of the orebody to be used during later ore production activities. The crushers may be operated simultaneously, particularly during the transition from the upper reaches of the mine to the lower levels. On the crusher level, ore would be transferred from the bottom of the orepass to the crusher by load haul dump (LHD) loader. Ore sourced from mining levels below the crusher level would be trucked up to the crusher. The ore would be directly tipped into the gyratory crusher pocket. Mist sprays would be used to control dust at the tipping pocket, with contaminated air from crushing activities directed to the mine ventilation system. Crushed ore would be stored beneath the crusher in a crushed ore bin. A temporary underground crusher may be established prior to the development of the deeper permanent crusher system and following construction of the decline conveyor system (see the following section). This would permit both ore and waste rock (if unable to be placed underground) to be conveyed to the surface for management at an earlier stage of the operation, decreasing the required haul truck fleet and reducing restrictions associated with traffic management within the decline. Conveyors and The conveyor system comprises a series of conveyors that transfer ore from the Haulage underground crushers to the surface run-of-mine stockpile. Such a system may, subject to detailed design, consist of: A feeder at the base of the crusher ore bin feeding onto a tramp conveyor A sacrificial tramp conveyor containing tramp metal magnets feeding the trunk conveyor Trunk conveyor and discharge chute feeding onto the lower conveyor A roof-mounted 1.4 km lower conveyor and transfer station A roof-mounted 4.6 km upper conveyor, discharging into a surface stockpile. The upper conveyor leg would be contained in one of the parallel access drives that make up the Tjati Decline. The crushing and conveying infrastructure would likely operate in combination with limited waste rock haulage via trucks, and provides ore and waste rock handling alternatives in the event that the conveyor system is unavailable. The construction of a shaft and installation of associated infrastructure for ore hoisting is a future consideration for the operation. Explosives Under the existing RL, a combined surface explosive magazine has been constructed to store up to 40 t of ANFO and high explosives and up to 20,000 detonators. The facility is adequate to support the early Tjati Decline mine access development and additional underground development. To support the production phase, the surface explosive magazine facility will be expanded to incorporate a 270 t emulsion storage facility. The underground operation will use AN emulsion as well as pre-packaged products, such as stope primers and emulsion type explosives for priming and perimeter charging. Approximately 1,300 t of AN emulsion would be used per annum for combined operations of development and production.
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2.1.5 Processing Activities
The Processing Plant will be located to the south-west of the existing Retention Lease (RL) accommodation village and to the south south-west of the orebody on a relatively flat area adjacent to the Tjati Decline portal (see Figure 2.1). This section outlines the proposed processing activities. The conceptual processing plant layout is shown in Figure 2.5.
Ore Processing Ore processing at Carrapateena would be based on a temporary single-stage crushing circuit (Year 1 to Year 2, until the establishment of the underground crushing infrastructure), followed by grinding and classification, flotation and concentrate treatment processes. Table 2.4 provides a description of the key ore processing elements. The indicative ore processing schematic flowsheet is shown in Figure 2.6.
Table 2.4: Ore Processing
Key Aspect Process Description Crushing and Initially, uncrushed ore would be transferred to surface via truck haulage. This would be Storage required in the initial one to two years of operation, following this, all ore would be crushed underground and transported to surface via a decline conveyor. Primary crushed ore would be transferred from the primary crusher discharge conveyor to the stockpile feed conveyor which stacks the ore in a conical open-air stockpile. The stockpile would provide 15,000 t live capacity. Uncrushed ore stockpiled at surface in the development ore stockpile (approved under the RL) would be reclaimed, crushed and transferred via the stockpile feed conveyor. Ore would be reclaimed from under the coarse ore stockpile by two or three duty apron feeders (nominally 7 m long with 1,200 mm wide pans) that would discharge directly onto the SAG mill feed conveyor. The rate at which ore is reclaimed from the stockpile would be maintained to a set point nominated by the plant operators by speed control of the apron feeders, based upon feedback from the SAG mill feed conveyor weightometer. Dust minimisation in the crushing plant would be controlled by means of water sprays at conveyor transfer and discharge points. Grinding and The grinding circuit may consist of a SAG mill operating in open circuit, with crushing Classification and recycling of SAG mill pebbles, and a ball mill operating in closed circuit with hydrocyclones to produce a product with a size distribution of 80% passing 75 µm. An alternative grinding process may be employed consisting of a single AG mill operated in closed circuit with hydrocyclones to produce the nominated particle size distribution without the use of the ball mill. All spillage from the grinding circuit would be contained within a concrete bund beneath the mills and surrounds. The bund floor would be sloped to direct slurry into sump pumps that are located within the bund area. Reclaimed spillage would be returned to the grinding and classification circuit. Flotation The flotation circuit for the Processing Plant would include: Rougher flotation in six tank cells Regrinding of the rougher concentrate in an IsaMill (or alternative regrind technology such as a VertiMill) Jameson cell and cleaner flotation in three stages, with Cleaner 1 in open circuit and Cleaner 2 and Cleaner 3 in closed circuit.
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Key Aspect Process Description Concentrate Concentrate from the Jameson cell and Cleaner 3 flotation would be pumped to a 15 m Thickening and diameter, high-rate concentrate thickener via a de-aerator. From the de-aerator the Filtration slurry would gravitate to the thickener feedwell prior to addition to the concentrate thickener. An auto-dilution system and addition of flocculant would be provided to increase the settling rate of the concentrate. The target thickener underflow density would be 65% solids. A froth management system consisting of rakes and sprays would be employed to prevent concentrate bearing froth reporting to the thickener overflow. The concentrate thickener overflow would be recycled to the process water pond by gravity and reused as process water. Thickened concentrate can then report to the CTP (see the following section) for further processing prior to sale. Tailings Thickener Flotation tailings would be pumped to a high-rate tailings thickener. An auto-dilution system and flocculant addition would be provided to increase the settling rate of the tailings. The target thickener underflow density would be 65% solids to maximise recovery and internal recycle of water, without necessitating the addition of more expensive and maintenance intensive positive displacement pumping infrastructure, and the need to install higher specification tailings lines (to handle the greater pressures). Tailings thickener overflow would be utilised as process water throughout the plant. Thickened flotation tailings would be pumped from the thickener underflow to the tailings storage facility (TSF) feed hopper via a sampling station for metallurgical accounting. From the TSF feed hopper, the tailings would be pumped to the TSF for permanent storage (see Section 2.1.6).
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Concentrate Treatment OZ Minerals has identified an opportunity for value adding in alignment with the South Australian Copper Strategy (Government of South Australia 2016), by treating the concentrate in a hydrometallurgical process to allow the removal of further deleterious elements such as uranium and, as a result, open up a wider market for the final concentrate.
Concentrate produced in the Carrapateena processing plant can be treated prior to sale via a Concentrate Treatment Plant (CTP). The final location of the CTP is currently being determined. The option to locate the CTP at Carrapateena has been included within the scope of this document for the purposes of assessing impacts should the CTP be located onsite. An off-site location would be subject to a separate approval process.
The CTP uses pressure leaching to remove iron and other impurities from the concentrate, reducing overall concentrate volumes by approximately 40% and increasing copper grades from approximately 35% prior to treatment to approximately 55% post-treatment.
Slurry or repulped concentrate from the flotation circuit would be fed to an atmospheric leach circuit consisting of a number of tanks operating in series, to which sulphuric acid and air are added. The resultant slurry would be fed to a titanium-lined non-oxidative (Nonox) autoclave at a nominal dry solids feed rate of up to 200,000 tpa.
The Nonox leach circuit, under the prevailing redox, pH, pressure and temperature conditions, alters the copper sulphide and copper iron sulphide minerals in the feed concentrate to a blend of secondary sulphides via metathesis. The sulphate-chloride lixiviant enhances the dissolution of radionuclides from the incoming feed material, with these reporting to the barren liquor stream. The Nonox discharge slurry is filtered and washed to recover the ‘super’ concentrate product as a filter cake, which is subsequently stored pending transport offsite.
As an alternative to the use of an atmospheric leach circuit, a portion of the ‘super’ concentrate may be repulped and fed to a Copper Pressure Leach (CPL) autoclave circuit, subject to the results of metallurgical test work. The brick-lined CPL autoclave would be a pressure oxidation leaching process that uses oxygen to effect conversion of the sulphide species to sulphate at elevated temperature and pressure. A flash thickener recycle (FTR) circuit may be employed in the CPL leaching process to improve process efficiency.
Barren liquor (pH 0.5) from the CTP will be directed to the flotation tails thickener discharge (see Table 2.4). The thickener underflow slurry (60-65% solids) would be pumped and deposited to the TSF (refer Section 2.1.6). The overflow from the tails thickener would be recycled to the processing plant for reuse in the flotation circuit. Whilst the flotation tailings have some acid neutralising capacity, this recycled liquor circuit may require further treatment (in the form of additional neutralisation and/or solids separation) prior to use within the flotation circuit in order to ensure flotation recoveries are maintained. This would be determined during detailed design and following additional metallurgical test work.
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2.1.6 Tailings Storage Facility
The section outlines the key TSF elements associated with design, construction, siting, operational controls and closure.
Design Basis The proposed TSF would be located at the head of the Eliza Creek valley, which drains to the north and is approximately 15 km upstream of Lake Torrens (see Figure 1.2). The design characteristics of the TSF are summarised in Table 2.5. The TSF design has been subject to an independent peer review undertaken by an industry expert (ACT Williams Pty Ltd) to confirm it is capable of managing the placement and containment of tailings in the short and long term.
Table 2.5: TSF Design Characteristics Summary
Item Comment/Details
General Total Tailings Volume Up to 73 Mm3 (including Stage 6)
Tailings Supply Rate 2.7 Mt in the first year of operation. Beyond the first year, the production rate varies between 4.0 and 4.7 Mt. Solids Concentration 65% w/w Tailings Deposition Life Up to 34 years (to the end of Stage 6) Mined Resource/Reserve The total ore reserve estimate is 70 Mt within a high grade Mineral Resource of 134 Mt. Total TSF capacity to the end of Stage 6 is approximately 145 Mt (dry), sufficient for the storage of tailings associated with the processing of the entire (current) Mineral Resource. Design Summary Impoundment Type Cross valley embankment Rate of Rise Initially up to 6.5 m/y, decreasing to approximately 1 m/y at Year 4 and 0.5 m/y at Year 20. Beach Slope 0.7% Consequence Category “Significant” (ANCOLD 2012 Guideline) Final Beach Surface Area 510 ha (to the end of Stage 6) Catchment Area 1,500 ha (including the decant dam storage area)
Siting Location of the TSF 12 potential TSF locations were considered. For each site, engineering considerations focused on minimising the footprint of the facility. This considered the use of natural topography and elevations to reduce earthworks, specifically: The materials required for construction of a paddock TSF versus a valley-fill TSF The length and height of the TSF embankment within a suitable valley The need for upstream saddle embankments The need to manage surface water (i.e. the size of the surface water catchment at the point of the TSF).
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Item Comment/Details
Embankment Construction Stage 1 20 m high, 1.1 km long, primarily formed with weathered rock and clay soil. Mine waste rock would also be used for erosion protection of the downstream embankment slope, and for the production of crushed rock that would be used to form the wearing course on the embankment crest. Stage 2 8 m downstream lift, 1.4 km long, constructed of weathered rock and clay soil, with waste rock erosion protection on the downstream slope and a crushed rock wearing course on the crest. Stage 3–5 7, 4 and 3 m upstream lifts, 1.7, 1.9, 2.0 km long, respectively, utilising tailings as fill material (with waste rock armouring for erosion protection). Stage 6 4 m upstream lift, 2.2 km long, tailings as fill material (with waste rock armouring for erosion protection). Freeboard Criteria and Design Event
Emergency storm storage allowance 1-in-100 AEP, 72-hour event Contingency freeboard (wave) 1-in-10 AEP, 72-hour event
Contingency freeboard (additional) 0.5 m
Spillway capacity during operation 1-in-1,000 AEP, critical duration event
Spillway wave freeboard allowance 1-in-10 AEP wind event
Operational freeboard 0.5 m
The gradient of the valley floor varies between approximately 7% in the upper reaches and 1% in the lower reaches. The valley slopes vary between approximately 10% near the top of the valley, decreasing to approximately 2% in the lower areas.
The valley floor in the area of the TSF consists largely of gravel and cobble-sized rock fragments, with investigations indicating that this colluvium layer is up to approximately 5 m in thickness. Arcoona Quartzite underlies the colluvium in the area of the TSF, with some areas of outcropping, and is estimated to be approximately 90 m thick below the TSF. This is underlain by approximately 30 m of Corraberra Sandstone and 270 m of Woomera Shale. Groundwater is located in the Corraberra Sandstone unit, approximately 90 m below the valley floor. The hydraulic conductivity of the upper zones of the Arcoona Quartzite is estimated to be approximately 1 x 10-9 m/s, excluding the effect of geological structures (i.e. faults).
Production Over the mine life, up to 145 million dry tonnes of tailings would be transported by pipeline to the TSF. The production rate would ramp up after Project commissioning with approximately 2.7 Mt in the first year of operation. Beyond the first year, the production rate typically varies between 4.0 – 4.7 Mtpa. Tailings production data for the mine life is summarised by stage in Table 2.6. A cross-section of the TSF is shown in Figure 2.7.
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Table 2.6: Summary of Tailings Production by TSF Development Stage Maximum Annual Tailings Produced Accumulative Tailings Stage Years (inclusive) Production in Period (dry tonnes) (dry tonnes) (dry tonnes) 1 1 to 4 15,258,293 15,258,293 4,429,985 2 5 to 8 17,443,776 32,702,069 4,743,242 3 9 to 14 27,614,452 60,316,521 4,694,853 4 15 to 20 27,767,048 88,083,569 4,704,035 5 21 to 26 22,388,535 110,472,103 4,612,431 6 27 to 34 34,500,000 144,972,103 4,312,500
Atterberg limits indicate a plasticity index of 7% (2014) and 3% (2016), which are typical of milled rock, and the particle size distribution indicates that the tailings would be classified as Clayey Sandy Silt (ML) under the Unified Soil Classification System. The tailings coefficient of permeability was measured at between 5.7 x 10-9 m/s and 1.4 x 10-9 m/s, and the tailings has an undrained strength ratio of 0.26 with a minimum undrained strength of 20 kPa.
Kinetic testing of tailings was completed in 2016 and indicates that the tailings are likely to be not acid forming (NAF) and there is a low potential for metals to leach from the tailings.
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TSF Water Management A summary of inflows and outflows for selected stages of the TSF is presented in Table 2.7. The tailings water balance is further linked with the site water balance provided in Section 2.1.8.
Table 2.7: Indicative TSF Water Balance
Percentage of Total Inflow Component Year 1 Year 2 Year 4 Year 8 Year 20 Year 34 (Stage 1) (Stage 1) (Stage 1) (Stage 2) (Stage 4) (Stage 6) Inflows Process water 83 83 83 82 82 78
Rainfall 17 17 17 18 18 22
Outflows Evaporation 17 23 40 46 52 59
Seepage 0.1 0.1 0.1 0.4 2.3 2.3
Retained interstitial 31 31 31 38 38 36
Decant return 51 46 29 16 8 3
The adoption of a simplified monthly water balance, in lieu of a detailed daily water balance is considered appropriate for the TSF design based on the regional climate. The climate of the site is arid, with infrequent rainfall events and a very low mean annual rainfall (approximately 180 mm) and a high rate of evaporation (exceeding rainfall by approximately 17 to 1 on an annual basis). The net monthly water volumes predicted by the water balance are relatively low with respect to the predicted runoff volume (425,000 m3) from the design rainfall event, i.e., a 1-in-100 year, 72-hour event that would be contained within the TSF impoundment prior to its discharge to the decant dam storage area.
Table 2.8: TSF Water Management Key Aspect Description Flood Storage For Stage 1 of operation, flood storage capacity would primarily be provided by Capacity additional freeboard at the embankment and the associated depression formed by the tailings beach against the embankment. The estimated volume of flood storage at Stage 1, allowing for the additional freeboard (up to 5 m at the supernatant pond location), is approximately 0.7 Mm3, sufficient to meet the ANCOLD requirements. During Stage 2 of operation, flood storage capacity would initially be provided by the additional freeboard created by the embankment raise. As the supernatant pond is translocated to the southeast of the TSF impoundment, flood storage capacity would be provided by the depression created by the tailings beach against the southeast side of the TSF impoundment. For Stages 3 to 6, flood storage capacity would also be in the depression created by the tailings beach, at the southeast of the TSF. The estimated storage capacity on the tailings beach at the end of Stage 6 is approximately 5.2 Mm3. Decant and Water Supernatant water would be removed from the TSF via a gravity outfall pipe, equipped Recovery with several decant inlets. Tailings would be spigotted from the perimeter of the TSF so that supernatant water collects near at least one of the decant inlets. Initially the pond would be located adjacent to the initial TSF embankment, with progressive deposition during future years directing the pond away from the embankment. Temporary decants would be provided during the early stages of TSF formation until the pond is established at its final location. Development of the pond in this manner allows OZ Minerals to
Carrapateena Project / March 2017 Page 36 of 172 Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
Key Aspect Description reduce the size of the initial TSF embankment, correspondingly reducing the amount of construction material required. Each decant structure would consist of a rock filter surrounding a 1.8 m diameter slotted reinforced tower. Water would flow via gravity through the rock filter and tower into a decant riser pipe consisting of slotted or drilled 250 mm diameter PVC pipe that is connected to a buried HDPE decant pipeline. Captured water would flow via gravity through this decant pipeline, under the TSF embankment and to a decant dam storage area for recovery to the processing plant. As the supernatant pond moves away from the embankment during the initial years of operation, temporary decant structures would be plugged with concrete and capped to prevent tailings ingress. A schematic of the TSF decant system is presented in Figure 2.8. As water enters each decant structure, it would flow out under gravity through the outfall pipework under the foundation of the cross-valley embankment and be temporarily stored in the decant dam storage area. The decant dam storage area would have a storage capacity of approximately 500,000 m3, designed to store a 1-in-100 year, 72-hour rainfall event, in addition to operational decant inventory that may be present in the dam prior to the rainfall event. This was calculated for the worse case operational scenario, representing the initial operational phase when the TSF is relatively small and the tailings is being deposited at 60% solids. In later years, as the TSF surface area increases, water recovery is expected to significantly decrease as a result of increasing evaporative capacity, and may not result in any operational flows to the decant dam storage area. Freeboard, Spillway Flood management measures include storage capacity within the TSF and decant dam and Surface Water impoundments and emergency spillways for both the TSF, and decant dam storage area. Management The flood storage capacity at each stage is sufficient to manage the Extreme Storage Allowance, i.e. the runoff from a 1-in-100 AEP, 72-hour event under tailings dam guidelines published by ANCOLD in 2012. A spillway would be included for each stage of the TSF development, located at the eastern abutment of the embankment. The spillways at the TSF and decant dam storage area would provide capacity to discharge a 1-1,000 AEP, critical duration rainfall event, also required by ANCOLD (2012). Floodwater in the TSF would be discharged via an emergency spillway. The decant dam storage area would also have an emergency spillway. The spillways would be in the order of 30 m wide and 1.5 m deep. An access road would be constructed around the perimeter of the TSF for both construction purposes and operation of the tailings delivery pipeline. The starter embankment includes a nominal 3 m of freeboard above the ultimate level of the tailings beach, equating to approximately 10 Mm3 of rainfall storage. This is sufficient for the storage of a 72-hour probable maximum precipitation (PMP) event of 742 mm of rainfall, and assuming the diversion drains are not operational and the supernatant pond is against the TSF embankment. During normal operations, the size of the supernatant pond is limited by evaporation losses and the recovery of returned water. The expected water storage capacity of the TSF would progressively decrease as the tailings height increases and freeboard decreases until additional capacity is provided by the construction of the additional embankment raise. The Stage 6 TSF water storage capacity is sufficient to retain a 72 hour PMP event in a 95th percentile rainfall year with 0.7 m freeboard (additional 3.1 Mm3 storage) remaining.
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Tailings Storage Facility Embankment The TSF would be formed by a cross-valley embankment to be constructed in six stages. Figure 2.9 illustrates the embankment design to Stage 6. The initial TSF starter embankment is described in Table 2.9.
Table 2.9: TSF Starter (Stage 1) Embankment Properties Parameter (units) Value Crest width (m) 6 Maximum embankment height (m) 20 (including 3 m freeboard) Downstream and upstream slopes 3H:1V Maximum crest elevation (m RL) 136.1
The starter embankment (Stage 1) would be constructed of NAF waste rock together with clayey gravel colluvium and weathered rock collected from the TSF impoundment area. The first TSF embankment raise (Stage 2) would be constructed in a downstream direction and of the same materials as the starter embankment.
The remaining four TSF embankment raises will be constructed in the upstream direction, with a final height of approximately 46 m at the highest point. The upstream raises will be constructed of compacted tailings with durable rock armouring on the external faces. The properties for the Stage 6 TSF embankment are presented in Table 2.10.
Table 2.10: TSF Embankment Properties Parameter (units) Value Crest width (m) 8 Maximum embankment height (m) 46 (including freeboard) Downstream slope 3H:1V Upstream slope 2H:1V Maximum crest elevation (m RL) 162.8
Seepage Management Seepage cut-off trenches would be excavated within the embankment footprint down to the quartzite bedrock, with the remaining embankment footprint scarified, moisture conditioned and compacted to achieve a competent foundation for the embankment.
Tailings deposition during Stage 1 would be by down-valley discharge and would result in approximately 12 m of tailings accumulating adjacent to the embankment during the first 3.5 years of TSF operation. Beyond Stage 1, the rate of rise would fall to below 2 m/year and by Stage 3, would fall to below 1 m/year. The lower rate of rise would allow additional time for drying and consolidation of the tailings, thus leaving the tailings in an unsaturated condition that may be more prone to seepage. Further, the
Carrapateena Project / March 2017 Page 39 of 172 Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
lower hydraulic conductivity of the extremely weathered bedrock sandwiched between the higher permeability colluvium clay soil and the fresh bedrock may promote the lateral transfer of seepage from the TSF.
To manage seepage, a number of mitigating measures are proposed. The development of the TSF would be undertaken in a manner that limits disturbance to the colluvium clay soils that form the TSF base, and act as a confining layer for seepage. A Geosynthetic liner would be installed in the upstream slope of the Stage 1 TSF embankment, anchored into the cut-off key trench at the upstream toe. This liner would have an effective permeability of less than 1 x 10-9 m/s and would be at least 1.5 mm thick. Coupled with this, an upstream sloping zone of compacted clay would be formed in the Stage 1 and Stage 2 TSF embankment for seepage control. For subsequent raises where the embankment extends onto natural ground, a central core of compacted clay would be formed. The compacted clay zones are protected against piping erosion by compacted weathered rock. At the decant dam, a central core of compacted clay, protected by compacted weathered rock, would be formed for seepage control. The cut-off key trenches would be excavated into the foundation of the embankments where contact would be made with the compacted clay zone. The depth would nominally be 0.5 m, to limit excavation into the underlying bedrock. The trenches would be backfilled with compacted clay as part of the main compacted clay zone in the embankment. Concrete grout would be applied to the base of the trench where the bedrock is exposed. The seepage collection drains would be formed by installation of: 160 mm diameter drainage coil pipes along the upstream toe of the TSF embankment, encapsulated in Drainage Aggregate wrapped in a geotextile. 300 mm diameter solid wall steel pipes through the foundation of the TSF embankment. One of the pipes (the primary seepage outlet) would be installed adjacent to one of the decant outfall pipes. Reinforced concrete would be formed to a trapezoidal shape around the pipes where they pass through the embankment. The reinforced concrete would limit the risk of piping erosion through potentially loose fill that would otherwise be placed around the pipe. A larger outlet pipe is proposed relative to the collector pipes, as the outlet pipes would also be used for water management, in conjunction with catch drains, during start-up works. Joiners would facilitate the transition between the drainage coil pipes and the larger steel outlet pipes. Puddle flanges would also be included at each joiner, to limit the potential for seepage between the pipe and reinforced concrete interface.
Where bedrock is exposed along the watercourses within the embankment foundation, grout would be placed over the cleaned bedrock surface to seal fractures with the objective to limit seepage flow at the interface with the embankment fill. With the inclusion of these seepage mitigation measures, seepage from the TSF has been estimated at less than 2.3% of the water balance, equating to a rate of approximately 13 mm/annum.
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Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
Evaporation Ponds There remains some uncertainty associated with the effect of CTP barren liquor on the efficiency of the flotation circuit should this liquor be recycled. An alternative management methodology is therefore being considered. This would consist of the treatment of barren liquor from the CTP with limestone, adjusting the pH from 0.5 to approximately 4.5. Precipitated solids would be separated from the neutralised liquor and directed to the TSF, with the remaining liquor either recycled to the CTP (where possible) and/or directed to dedicated evaporation ponds located upstream of the ultimate (Stage 6) footprint of the TSF. The subsequent environmental impact assessments have considered the construction and operation of evaporation ponds upstream of the TSF.
Under this alternative, two evaporation ponds of approximately 53 ha and 70 ha may be established in the upper-most reaches of the Eliza Creek catchment, upstream of the TSF (see Figure 1.2) for the purpose of CTP barren liquor management. These would consist of a number of (potentially terraced) low embankments for the containment of barren liquor and would be separated from the greater TSF via saddle dams.
Placement of the ponds in the upper-most extent of the Eliza Creek catchment reduces the volume of surface water run-off that would require management, limiting it to incident rainfall. The saddle dams would be fitted with engineered spillways that would allow captured surface water to be discharged to the TSF for recovery via the TSF decant infrastructure in the event of a large rainfall event (see Table 2.8). The barren liquor reporting to the evaporation ponds would be pH 4.5 and hypersaline, with elevated concentrations of some metals. A comparison of heavy metal concentrations against relevant toxicity criteria indicates that no significant impacts are likely. Post-closure, the evaporation ponds would be decommissioned and rehabilitated.
Carrapateena Project / March 2017 Page 42 of 172 Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
2.1.7 Materials Handling and Management
The construction and maintenance of various Project elements, including development of hardstand areas, building and stockpile foundations, underground shotcrete, road construction, fibrecrete manufacture and TSF wall raising activities, requires the use of rock and soil materials of various qualities.
The demand for soil and weathered and fresh rock construction materials would be met through a combination of: The re-use of material stockpiled within the RL WRL (see Section 2.1.2) Use of topsoils and subsoils generated during land clearance activities (see Section 2.1.13) Fresh and weathered rock generated during underground mine development (see Section 2.1.3) Where necessary, from surface quarrying activities and borrow pits (see Table 2.11).
A summary of the materials sources and demands is illustrated in Figure 2.10.
Table 2.11: Construction Material Key Aspect Description Subsidence Zone Quarry A quarry would be established within the footprint of the SLC subsidence zone for extracting soil and weathered rock for use in ML construction activities prior to the commencement of underground SLC mining operations. The quarry slopes have been designed at a conservative 45-degree angle through the Arcoona quartzite and 20 degrees through the top and sub soils (see Figure 2.11). The first bench would be approximately 4 m deep, excavating the top soil and subsoils. The following two production benches are 8 m deep. These are both in the competent Arcoona quartzite and would need to be drilled and blasted, and mined one at a time. A safety windrow would be added around the quarry to stop access by unauthorised personnel. There is to be a 10 m berm between the edge of the quarry and the inside toe of the windrow, and a single 11 m wide ramp would be provided to the quarry workings. Borrow Pits The construction of key Project elements within the Western Infrastructure Corridor MPL, including the western access road and transmission line, would require clay soil (for use as compacted clay) and weathered rock (for use as compacted weathered rock) for road construction. It is planned to excavate this material from approximately 17 borrow pits along the Western Infrastructure Corridor. The borrow pit locations remain conceptual and would be subject to further investigation. Conceptual borrow pit locations are shown in Figure 2.12. Tailings Construction Proposed borrow pit locations and other areas that may have potential for Borrow Pits/Quarries harvesting embankment fill material based on the outcomes of site geotechnical investigations are shown in Figure 2.1. Seven locations have been identified just outside the footprint of the TSF. The seven borrow pits would be operated intermittently to recover material for direct use in each embankment lift construction. Extraction of clay soil and weathered rock would occur in 1 m thick benches up to total depth of 3 m.
Carrapateena Project / March 2017 Page 43 of 172 Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
Waste Rock Stockpile A WRS is proposed for the temporary storage of waste rock material generated as a result of underground mine development operations. This would be established on the footprint of the existing RL-approved WRS and would be consistent in design and operation to that approved under the existing RL. The management of surface water is described in Section 2.1.8.
Upon approval and commencement of ML activities, the remaining RL-generated material within the WRS would, where suitable, be reclaimed and used for ML construction (e.g. TSF embankment construction, the Processing Plant and surface infrastructure foundations etc.).
After the initial ML construction activities are completed, waste rock would continue to be generated from the development of the underground workings. Material stockpiled in the WRS may be progressively used for TSF wall raising activities during operations, to supplement material obtained more locally to the TSF from borrow pits.
At the completion of operations, any waste rock material on the ML WRS may be reclaimed for use in closure activities, specifically for use in SLC subsidence zone abandonment bunding, as TSF stability and/or erosion control, backfilling of borrow pits and underground mine voids (i.e. ventilation shafts and/or the surface Tjati Decline portals and boxcuts).
Carrapateena Project / March 2017 Page 44 of 172 Subsequent Approved Retention Lease Activities noitcurtsnoC seitivitcA snoitarepO dna erusolC seitivitcA Approvals
Sub-level Cave Topsoils from Western Decline Engineering Tailings Storage (SLC) Infrastructure Infrastructure Development SLC Quarry Cut and Fill Facility (TSF) Extractive Underground Development RL-approved Material Borrow Pits Minerals Development (where available) Borrow Pits
SLC Quarry SLC Quarry TSF Borrow Pit TSF Borrow Pit Waste Rock Fresh Weathered Weathered Waste Rock Clay and Weathered Waste Rock Landform (WRL) Quartzite Quartzite Quartzite and Topsoil Colluvium Quartzite Stockpile (WRS) RL-approved Stockpile Stockpile Stockpile Stockpiles Stockpile Stockpile
Fibrecrete / Shotcrete Manufacture
Processing SLC Subsidence TSF and TSF and SLC Subsidence Western Underground Roads and Plant and Evaporation Land Zone Decant Dam Decant Dam Zone Infrastructure Ground Infrastructure Pond Disturbance Hardstand Abandonment Access Road Support Abandonment Foundations and Embankment Embankment Areas Embankments Bund Rockfill Rehabilitation Bund Fill Infill Fill Armour Construction
Intermediate Material Supply Material Option Treatment
Intermediate Material Material Fate Storage
Figure 2.10: Material Movement Balance
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Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
2.1.8 Water Demand, Supply and Distribution
The construction of Project infrastructure and operation of the various Project activities would require the supply of water of various qualities. This would nominally be achieved through the abstraction and treatment (as necessary) of groundwater from the local and the greater regional area. This section describes the water demand and supply for the construction and operation phases.
Construction and Operations Water Demand Water demand during construction and operation is described in Table 2.12. The indicative water demand for construction and operations is summarised in Table 2.13.
Table 2.12: Water Demand
Key Aspect Description Construction Water Water would be needed during the construction phase for road, hardstand, building and Demand stockpile foundation construction works, on-site concrete manufacture and for dust suppression during land clearing activities. It is estimated that an average of around 2.5 ML/d of groundwater would be required during the construction phase, with some additional higher-quality water needed for concrete manufacture, potable uses associated with the accommodation of the construction workforce and other minor construction uses. Operations Phase Operational water demands are largely associated with the grinding and flotation of Water Demand mined ore within the processing plant, together with less significant volumes associated with underground mining operations, concentrate treatment processes, accommodation village potable water requirements and on-going infrastructure (e.g. access road) and dust suppression requirements. This demand would be split between raw water, water suitable for reverse osmosis (RO) treatment and hypersaline brine.
Table 2.13: Indicative Carrapateena Water Demand Peak Water Demand Average Water Demand Scenario (ML/d) (ML/d) Construction 2.5 2.5
Operations (no TSF return) 9.2 8.6
Operations (20% TSF return) 7.7 7.2
Operations (On-site CTP, no TSF return) 12.75 12.15
Carrapateena Project / March 2017 Page 48 of 172 Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
Construction and Operations Water Supply The groundwater supply for the construction and operation is described in Table 2.14.
Table 2.14: Water Supply Key Aspect Description Construction Raw water demands associated with on-tenement construction activities would be sourced Water Supply from the existing RL-approved Radial Wellfield (see Figure 2.13), which would be expanded to provide the required quantity and quality of raw water. Water supply within the Radial Wellfield would be drawn from a number of production wells, predominantly from the Tent Hill Aquifer (THA), and would be blended as necessary to meet the required quality parameters. This may be supplemented by reclaimed mine dewatering water if this is able to be collected at usable volumes and quality. The Radial Wellfields are located across three proposed tenements: RL 127/proposed ML Eastern Radial Wellfield MPL (north-eastern arm) Southern Access Road and Radial Wellfield MPL (southern arm). Construction of the electricity transmission line, access road and optional water supply pipeline in the Western Infrastructure Corridor would use groundwater wells installed at approximately 10 km spacings along the alignment, with each site fitted out with submersible pumps that extract groundwater to a tank or lined turkey’s nest dam prior to loading into water carting trucks. Operations A groundwater water supply network is proposed to support the on-going Project operations. Phase Water This would be based on a continuation of the Radial Wellfield supply utilised during the Supply construction phase (see previous section). During operations, this water supply would be supplemented by groundwater production wells established outside the proposed tenements described within the MLP via a Regional Project Wellfield. This may be further supplemented by the use of reclaimed TSF decant water (refer Section 2.1.6) and/or water collected from the mine dewatering systems (described in Table 2.3). The water supply infrastructure has conservatively been sized assuming that TSF decant and mine dewatering water would not be used, reflecting the uncertainty regarding the typical seasonal trend return from any TSF operation, and the potential range and sustainability of mine dewatering inflows during operations. A number of the water supply scenarios contemplate the use of hypersaline waters. These hypersaline waters would be blended with waters from the THA and the Whyalla sandstone. Blending of waters presents operational risks due to potential for saline waters to enter the flotation circuit, high treatment costs, increased maintenance and potential precipitation of solids in blending. OZ Minerals will continue to investigate the Project water supply options to avoid unnecessary use of the hypersaline waters. An operational water balance is described in Figure 2.14.
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Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
Water Distribution and Infrastructure Produced groundwater would likely be of variable quality with respect to TDS. The quality of the groundwater is determined by the aquifer (e.g. THA regional water quality is approximately 35,000 mg/L TDS, while Whyalla Sandstone Aquifer (WSA) regional water quality is approximately 100,000 mg/L TDS), and the location (e.g. THA water quality within the vicinity of Lake Torrens is approximately 250,000 mg/L TDS). Abstracted water would likely be blended together and/or treated as necessary to ensure a consistent raw water quality for the Project whilst meeting the water quality requirements and volume demands outlined earlier in this section. An alternative is to separate abstraction lines based on operational use (e.g. saline for treatment and/or construction uses, and hypersaline for salt tolerant construction operations). Conceptually, the water supply infrastructure illustrated in Figure 2.13 would consist of: Production wells drilled to depths approximately between 120 m (THA installations) and in excess of 450 m (Whyalla Sandstone) are expected to deliver groundwater into a header pipe, which would terminate at a raw water break tank. Each raw water break tank would be equipped with a pair of transfer pumps (duty and standby). The pumps would deliver into a transfer pipeline. Wherever possible, the transfer pipelines would be installed parallel to existing pastoral tracks to minimise land disturbance. The wells would be powered by self-bunded diesel electricity-generating sets. All pumps would be controlled through a telemetry system from the processing plant. Water flow monitoring of each input to the groundwater pipeline would be incorporated to enable real-time monitoring of the water flows. All wells would be fitted with stainless steel submersible pumps, impellers and motors or an equivalent alternative pumping technology. Shrouds would be attached to submersible pumps to assist with cooling of the motor when required.
Water produced from mine operations, the Radial Wellfield and the Regional Project Wellfield would be distributed around site via a series of pipelines and transfer stations. Table 2.15 presents the treatment and distribution of water in terms of use and production location, with the major water holding ponds described in the following section.
Table 2.15: Water Treatment and Distribution Key Aspect Description Potable Water The reverse osmosis desalination (RO) plant is an approved activity under RL 127. This would be relocated to the new accommodation village to provide water for some aspects of the process, together with other potable uses including ablution, safety shower and drinking water facilities. The plant would have a feed capacity of approximately 0.7 ML/d and generate product water with a salinity concentration of 100 mg/L. The reject water stream from the RO plant would be re-used within the processing plant, transferred to the TSF or disposed of into permitted groundwater injection wells (IS1, IS2 and IS4). Waste Water Waste water generated within the operational areas and the accommodation village Treatment Plant would be pumped to a single waste water treatment plant (WWTP) to be located adjacent to the proposed accommodation village.
Carrapateena Project / March 2017 Page 51 of 172 Project Radial Mine Wellfield Dewatering Rainfall (Future) Wellfield
3.6–8.6 ML/d 7.3 ML/d Mine Settling Ponds
Accommodation Dust Suppression Waste Water 0.7 ML/d Reverse 1.55 ML/d Village and Process Water and Other Treatment Plant Osmosis Plant Raw Water Pond Amenities Pond Minor Uses
0.8 ML/d 0.05 ML/d 0.7 ML/day (brine) (RO water) (brine)
3.55 ML/d 2.7 d/LM 0.2 d/LM 0.7 ML/d Irrigation or Aquifer Concentrate 0.05 ML/d Processing (moisture in ore) Return to Reinjection SLC Mine Evaporation (as required) Treatment Plant (moisture in concentrate) Plant Process Water Pond 7.95 ML/d Tailings thickening
Super 0.3 ML/d 4.4 ML/d Tailings Concentrate (moisture in concentrate) Disposal
3.8 ML/d Entrained water 1.4 ML/d (in tailings) in tailings
Water Supply Option
0.3 ML/d Seepage Tailing S torages 0.3 ML/d Decant F yacilit Storage Pond Water Demand
1.9 ML/d Water Fate Evaporation Rainfall
Figure 2.14: Indicative Water Balance
CARRAPATEENA PROJECT Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
Surface Water Distribution and Infrastructure The management of surface waters would be based on the separation of overland and ephemeral surface water flows originating from undisturbed areas of the lease. The management would target surface water run-off that has interacted with disturbed land. The system is illustrated in Figure 2.15 and the basis of the system design is as follows: Water that contacts disturbed land (e.g. the run-off from the processing plant etc.) needs to be collected/contained and managed prior to release (if captured water stores are at capacity or the water is unable to be reused within the operation). Water that contacts undisturbed land should be diverted around areas of disturbance to limit the volumes of water requiring management and to minimise effects to pre-mine watercourses. Diversion would be designed to keep surface water flow within its originating catchment where possible. Diverting water around the SLC zone of influence (fracture and subsidence zone) to minimise water inflows to the underground workings and avoid post-closure degradation of the abandonment bund.
Captured run-off from the disturbed land around the WRS, stockpiles and processing plant would be directed to the site Event Pond. From the Event Pond, stormwater would be directed to a settling pond and subsequently to the process water dam for re-use in the metallurgical process.
A network of containment and diversion drains consisting of unlined excavations and bunding would be constructed around the processing plant area (including the mine portal and WRS) to re-direct surface water flows. Drains would nominally be 4.0 m wide by 0.5 m deep, with a wall angle of approximately 30 degrees for a total flow area of approximately 2.3 m2. The sizing for the bunding will be finalised at detailed design. The drains/bunds are designed to re-direct clean surface water flows around the processing plant area and mine surface infrastructure area into the existing surface water catchments and to capture run-off from the disturbed areas around the WRS, processing plant and mine portal.
Similar surface water diversion infrastructure and bunding would be established around the mine infrastructure associated with the SLC operations. In this instance, flows would be directed to detention ponds that would be sized to capture all waters for infiltration and evaporation up to approximately a 1-in-50-year rainfall event. Beyond a 1-in-50-year rainfall event, flows would be slowed to remove sediment prior to discharge of waters into existing watercourses. Any pond that reaches 60% of its operational capacity should be cleaned out. Based on sedimentation volumes and excavation sediments, ponds should not be allowed to fill to higher than 1.2 m below the spillway water level.
Water holding infrastructure to be established on site is described in Table 2.16.
Carrapateena Project / March 2017 Page 53 of 172 Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
Table 2.16: Surface Water Holding Ponds
Key Aspect Description Mine Settling Ponds A system of two settling ponds and one holding pond for management of water from the mine. The settling ponds each have a storage volume of 0.448 ML with the larger holding pond having a capacity of 0.896 ML. Each are HDPE-lined and a design freeboard of 1 m. Process Settling An HDPE-lined pond, with 1 m of freeboard and a capacity of around 1 ML, for the Pond settling of sediments associated with captured surface water run-off prior to direction to the Event Pond. Process Water Pond The primary staging pond for all water inputs additional to the raw water supply. It is a HDPE-lined facility with a capacity of 7.8 ML with 0.3 m freeboard. Raw Water Pond The raw water pond receives all the groundwater produced for operational needs. It is a HDPE-lined facility with a 2.5 ML capacity and overflow to the process water pond. Event Pond Site drainage and overflow from storage ponds would be collected in the event pond. The event pond (stormwater pond) has a capacity of 14.5 ML and is HDPE-lined.
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Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
2.1.9 Site Access and Logistics
The existing and proposed site access and infrastructure layout is illustrated in Figure 2.16, and described in further detail in Table 2.17.
Table 2.17: Site Access and Logistics
Key Aspect Description Transport Copper-gold concentrate would be transported via the Site Access Road and rail to either Logistics Port Adelaide or alternative ports. The concentrate would be transported in dedicated containers similar to those used at Prominent Hill. These containers feature a removable and locking lid that provides a weatherproof seal when fitted, and a design that minimises the potential for material to build up on the lip of the lid, thereby minimising the potential for spillage. The containers are unloaded via a “rotainer” arrangement that simultaneously removes the lid and tips the container for delivery to a ship hold. Each container carries up to a maximum of 29 t of concentrate with each truck moving approximately 87 t per trip, while trains would move approximately 3,000 t per load. Containers are weighed upon despatch. These containers have been utilised at the Prominent Hill operation since 2012 and photographs of the existing transport and shipping operations are shown in Plate 2.1 and Plate 2.2. Nominally eight concentrate truck movements (or equivalent via alternative transport options like rail) to Port Adelaide or alternative ports would occur daily should the CTP not be located on-site. This is partly due to the Iron Calcium Precipitate material generated from an off-site CTP returning to the Carrapateena TSF (discussed further below). Existing Site Existing site access is via a dedicated access road to the south of the current RL and the Access proposed ML, joining the gazetted road at Pernatty Station, and passing through South Gap Station prior to joining the Stuart Highway approximately 80 km (by road) north-west of Port Augusta. This road may be upgraded during the initial ML construction phase, although this would be done through an agreement with Department of Planning, Transport and Infrastructure (DPTI) South Australia. Any upgrades to the Southern Site Access would also consider public safety at the turn off to the Stuart Highway with appropriate measures agreed with DPTI. If the Project proceeds with the southern access option, a bypass around the Pernatty homestead would be constructed. Site Access Road An alternative primary site access is proposed to be established to the west of the proposed Mining Lease, intercepting the Stuart Highway at Mount Gunson, approximately 52 km south-east of Pimba by road. The road would be similar in principal and construction to the proposed upgrade of the Southern Access Road and would be constructed of formed, graded and compacted imported crushed material, with either a cross-fall or crown. The design would allow for fords or culverts in low sections and creek crossings to minimise disruption to natural surface water flows. Design would provide for sufficient drainage, and land clearance would be managed to avoid areas of particular habitat sensitivity. Access would be restricted only to the extent necessary for mine construction and operations, as well as for pastoral lease management. No public access would be permitted. Rail Siding and The existing railway siding at Wirrappa may be upgraded to be consistent with the existing Haul Road OZ Minerals-operated Wirrida rail siding, with the installation of a 1,000 – 1,500 m long hardstand area to facilitate forklift use and provide an area for temporary container storage for up to 800 containers. A truck turning area would be allocated, together with facility lighting. A transportable-type administration office may be provided, together with portable ablution facilities. If a rail siding was required it may be necessary to also develop an underpass under the Stuart Highway to safely access the rail siding from the proposed Western Access Road.
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Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
Waterway Crossings Concrete-lined fords and culverts will be installed as required for road crossovers and storm water drainage and described in Table 2.18 and shown in Plate 2.1. They would be located and orientated to minimise disruption to existing drainage paths. Scour protection would be designed to limit erosion under the design flow conditions. Creek crossings would be constructed to allow vehicles to cross creeks without causing creek bed erosion.
Table 2.18: Waterway crossings
Key Aspect Description Concrete-Lined Fords Fords would be located in a straight stretch of the stream or at the crossover point of a meander where flow is directed through the centre of the channel. The stream bed would be concrete lined so that the natural cross-sectional area and shape of the channel is preserved as much as possible. The fords would be kept as low as possible (less than 300 mm where practicable) to reduce the risk of head cut processes undermining the crossing. The concrete would extend across the stream to above the highest flood level to avoid the possibility of floods scouring a bypass around the crossing. Culverts Culvert inlet design would ensure that the potential for displacement of the culvert structure during large flood events is minimised. Drainage channel outfalls would have scour protection (stone pitching or lining) as required. Culvert materials for use for storm water drainage and road crossovers may include reinforced concrete pipes, corrugated steel culverts and PVC. The wall thickness of culverts would be designed to accommodate the embankment height above each culvert plus superimposed wheel loads, including construction vehicles as applicable in accordance with the relevant Australian Standards. Culverts would also be designed to accommodate fluid pressures if applicable as determined by the hydraulic computations to the relevant Australian Standards.
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2.1.10 Electricity Demand, Supply and Distribution
The Project is anticipated to have an average power load ranging between 40–57.5 MW. Electricity supply to the Project would occur in two distinct phases, with construction activities supplied via on-site (diesel) generation and operational electricity demands met through connection to the South Australian electricity network supplemented by an optional onsite generation capacity.
The operational power supply for the Project is proposed via a132 kV overhead transmission line to the South Australian electricity network at Mt Gunson, located approximately 55 km from the Project site (see Figure 2.17). This 132 kV overhead transmission line would then connect to site via a 132/22 kV substation where the 132 kV supply would step down to 22 kV and be further reticulated to other users such as mining, surface operations facilities and accommodation facilities via overhead transmission lines. Additional fit for purpose site electrical infrastructure, substations and reticulation will be installed across the site.
The proposed transmission line route would be contained within the proposed Western Infrastructure Corridor, which would also contain the site access road. The transmission line design is based on the use of monopoles ranging in height from 17 m to 30 m spaced approximately 250 m apart, depending on topography. The proposed alignment has been selected based on the following considerations: Refining the alignment with Kokatha Aboriginal Corporation through a series of heritage surveys Crossing of sand dunes is minimised by aligning the transmission line around the major sand dunes Using existing pastoral tracks where possible thereby reducing clearance requirements Minimising the number of stakeholders directly affected Maximising the use of existing infrastructure (connecting to the existing 132 kV transmission line between Davenport and Pimba) Reducing the length of new infrastructure.
Table 2.19: Key Design Criteria and Characteristics of the Transmission Line Item Description Single circuit transmission line between the new Mount Gunson South substation Transmission line and the site Transmission voltage 132 kV
Tenement type Miscellaneous Purposes Licence (MPL)
Transmission line length 55 km
Operating hours 24 hours
Tower type Monopoles and olive conductor (see Plate 2.4)
Number of towers 210 to 220
Height of tower 17 m – 30 m
Footings Bored pier in-situ concrete footings with holding down bolt assemblies
Power source Connection to the South Australian electricity network at Mt Gunson
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Example Monopole Example 11kV Switch Room – Prominent Hill
Example 132kV to 11kV Substation – Prominent Hill Example 11kV Switch Room – Prominent Hill
Example 132kV to 11kV Substation – Prominent Hill Mount Gunsun Substation
Plate 2.4: Indicative Electricity Infrastructure
CARRAPATEENA PROJECT Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
2.1.11 Non Process Infrastructure
A number of non-process infrastructure items are required to enable the site to function during its construction, operation and closure phases, described in Table 2.20.
Table 2.20: Non Process Infrastructure Key Project Elements Key Project Summary Element Communications Communications for voice and data for site would be connected to a National Network Carrier either at the Mt Gunson substation via a 48 fibre OPGW cable or direct bury fibre via Woomera. A mobile network tower, antennas and system (3G or better) connected into the main communication would be installed on the lease to provide mobile phone communication in the processing plant, accommodation village and surrounding areas. A radio communications system, including antennae tower, would be installed near the village and other areas requiring coverage across the lease. Security and Visual The proposed Project Area and Site Access Road would be fenced where necessary (e.g. Screening at vehicle access points and fence line intersections) to discourage stock access. Security gates/stock grids would be constructed to control access to and from the mining lease area. Offices and All office buildings, cribs and first aid facilities would be steel clad, steel framed modular Workshop Facilities transportable buildings. A processing plant workshop and warehouse would be contained within a single steel-framed building including two roller doors, front and rear, for vehicle access. A fenced compound would be installed at the rear of the warehouse to enable secure storage of large bulk items. The mobile equipment fleet required for mining works is supported by a workshop facility adjacent to the processing plant. The laboratory would provide support for mining and processing operations by routine analyses for mine grade control, processing plant metallurgical control and accounting and on-site metallurgical test work. Vehicle Wash- Both heavy vehicle and light vehicle wash down facilities would be established. The downs facility would consist of a high-pressure hose and self-bunded concrete platform. Waste Management A landfill may be constructed at Carrapateena for the disposal of non-hazardous wastes Landfill in accordance with relevant SA EPA Guidelines for a class SB - landfill. It is anticipated that approximately 1,000 t of waste material would be disposed of to the landfill each year. Alternatively, waste may be collected in a waste transfer station pending transport to an appropriately licensed off-site waste management facility. Waste Management The RRC and recycling yard would be a purpose-built work area under the management Resource Recovery and operation of the waste services contractor. The purpose of this yard would be to Centre provide a central location for contractors/site staff to segregate recyclable material such as steel, cardboard, timber, batteries, aerosols and lighting, and store recyclable material prior to transport offsite. Waste Management A bioremediation area (or BioPad) would be established, consisting of a contained area Bioremediation Pad purpose built for the bioremediation of contaminated soil and storage of waste hydrocarbons and other hazardous/listed wastes that require containment. The BioPad would be approximately 15 m wide and 15 m long and have a blind sump with a manual bilge pump to allow transfer of water to a storage tank on the Biopad.
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2.1.12 Closure and Rehabilitation
The overarching goal of the site closure and rehabilitation is to identify and evaluate and integrated asset closure solution that creates a safe, stable, resilient, and achievable closure outcome acceptable to key stakeholders. The strategy seeks to deliver post-closure conditions that will support the pre-mining land uses and landscape functions.
A summary of the Project approach to closure is presented in Table 2.21.
Table 2.21: Closure and Rehabilitation Key Project Summary Element Post-closure Land There are two identified categories of post-closure land use: Use Returned to pre-mining land use - productive pastoral use and/or ecosystem functions Permanent Post-Closure Structures (TSF and Subsidence Zone). Minimising post-closure landforms has been a key priority during the design phase of the Project. For example, reuse of waste rock in construction and preferentially disposing of PAF waste rock underground instead of bringing it to surface and encapsulating it in a landform. The vast majority of the site will be returned to pre- mining land use with the only permanent post closure landforms being the SLC subsidence zone and the TSF. Proposed Closure The closure strategy has been developed with a view to delivering the following closure Objectives objectives: Soil quality - Physical and chemical properties of surface soils are compatible with agreed post-closure land uses Water quality - No reduction in beneficial use of natural water drainage systems, streams and rivers or groundwater as a result of Project-related contamination Air quality - No human health impacts as a result of dust or/and radiation emissions and no nuisance impacts to local pastoralists or reduction in vegetation and habitat abundance and diversity as a result of post-closure dust emissions Groundwater - No adverse impacts to existing groundwater users (including groundwater dependent ecosystems) as a result of changes to groundwater levels or flow patterns Surface water - Post-closure flow systems reinstate, to the extent practicable, pre- mining flow patterns and post-closure flows do not give rise to instability of built landforms, release of contaminated sediment to natural drainage lines, waterlogging or flooding Vegetation - Diversity and structure of revegetated areas show satisfactory trend, approaching comparable values for species richness, species abundance and vegetation condition in appropriate analogue communities Safety - Mine voids, subsidence areas and engineered landforms are stable and/or made safe through effective access controls and no reactive or chemically toxic materials are left at the land surface or placed in locations where they could give rise to environmental pollution that leads to a negative environmental impact Landscape amenity - Permanent landforms are designed to be consistent with the surrounding landscape Social - Disruption/impact on the community caused by closure, for example, that caused by reduction in access to infrastructure, is minimised Economic - No residual liability or costs for mine rehabilitation or post-closure maintenance accrues to the South Australian community or future generations. Closure design make provision for reasonable access for future mining (or reprocessing) of remaining resource.
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Key Project Summary Element Progressive Progressive rehabilitation will be implemented to the extent practicable, with a view to: Rehabilitation Limiting dust emissions from disturbed land surfaces Limiting the generation and discharge of sediments during rain events from disturbed surfaces Testing the effectiveness of rehabilitation procedures Reducing the amount of rehabilitation required at Project completion Demonstrating OZ Minerals’ commitment to sound environmental practices. Key Project elements that will be targeted for progressive rehabilitation works include: Borrow pits Exploration disturbance Lower lifts of the TSF embankment Perimeter bund surrounding the subsidence area Areas of the accommodation facility (if surplus to requirements following the construction phase) Closed landfill cells. Unplanned Closure In the event of a temporary suspension of mining activities, a care and maintenance plan will be prepared. DSD will be notified of the nature of the suspension and measures in place to limit impact to the environment and ensure health and safety requirements are met. The care and maintenance plan will not consist of a full rehabilitation plan and closure strategy, but will incorporate interim measures. Planned Closure Landforms (being the TSF and the SLC subsidence zone) will remain post closure however; these are not anticipated to dominate the landscape, with the TSF being located in a valley and the ultimate height being lower than the surrounding ridgelines. The SLC subsidence zone will have rock armoured abandonment bund and mine voids will be plugged to restrict public access post closure. All other infrastructure will be decommissioned, removed and the land rehabilitated to a landscape function equivalent to the surrounding landscape and pre-mining land use. The post closure landscape has been shown in Figure 2.18. The general sequence of mine rehabilitation and closure activities is summarised below: Stakeholder engagement to discuss proposed closure outcomes and the strategies by which these may be achieved Periodic review and update of the mine closure plan and closure cost provision to include additional technical/cost information and reflect the outcomes of stakeholder consultation Progressive rehabilitation Progressive rehabilitation of land disturbance Remove any residual structures or pavements and other fixed or demountable structures no longer required for operations Conduct contamination survey and clean up contaminated areas as required Re-contour and rip former roads, laydown areas and other cleared areas Review Access requirements decommissioning roads no longer required Conduct a safety audit of safety bunds, mine access controls and the TSF Commence post-mining closure completion requirements.
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Figure 2.18: Pre and Post Carrapateena Project Cross-sections B'
CARRAPATEENA PROJECT Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
2.1.13 Project Footprint Summary
The Project will require the clearance or disturbance of the underlying land. OZ Minerals is required to provide a Significant Environmental Benefit (SEB) for any vegetation clearance under the Native Vegetation Act 1991 (Section 2.4.4). An SEB must provide an environmental gain over and above the impacts of an approved clearance (DEWNR, 2017).The SEB may be established via a number of different options, including monetary contribution to the Native Vegetation Fund (NVF), management of native vegetation for conservation purposes, direct revegetation and/or on-ground works. To enable recommendation of future SEB offset options and calculation of cumulative effect and impact to the land system, vegetation associations and habitat, OZ Minerals has contemplated both a buffer and potential future activities to ensure a conservative assessment can be undertaken. A summary of the Project footprint, including buffers representing approximately 20% additional disturbance, is presented in Table 2.22.
Table 2.22: Existing, Scheduled and Proposed Project Footprint Project Area Description Footprint (ha) Existing RL-related land disturbance (OZ Minerals 2016) 71.66 Scheduled Airport (MPL Management Plan currently under assessment) 92.02 Scheduled Village (MPL Management Plan currently under assessment) 34.75 Scheduled Access Road 7.42 Projected additional RL-related land disturbance 270.30 Total RL-related land disturbance (includes Airstrip and Accommodation Village MPL) 476.15 SLC zone of Combined SLC subsidence and fracture zones 166.6 influence Subsidence Material stockpiles outside of abandonment bund 7.7 Zone Quarry Accommodation Accommodation Village access road 3.4 Village (ML- Village common services trench 6.7 portion) On-lease wellfield infrastructure, including groundwater abstraction and Radial Wellfield injection wells, pumps and staging tanks supporting the North-eastern 24.5 (ML-portion) Arm and Southern Arm wellfields Project Wellfield Wellfield pipeline 43.4 (ML-portion) Explosives magazines, including storage tanks, detonator and high 3.3 explosives magazines and the magazine access roads Mine Surface Mine refrigeration plant 5.3 Infrastructure Mine ventilation fans and intakes/exhausts 8.4 Portal infrastructure 45.1 132 kV transmission line poles (ML-portion) 0.5 Electricity 132 kV transmission line access track (ML-portion) 5.5 Transmission Low voltage transmission line (on-site power generation) 4.7 Lines Low voltage transmission line (Village) 13.7 On-site Power On-site power generation and infrastructure 61.9 Generation
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Project Area Description Footprint (ha) Processing Plant infrastructure 25.4 Processing Plant Topsoil stockpiles 3.0 TSF including embankment and decant dam 967.4 Evaporation ponds 160.2 Tailings Storage Tailings disposal pipeline 14.6 Facility TSF construction borrow pits 81.9 TSF borrow material stockpiles 4.4 TSF decant return pipeline 11.5 Site western access road 19.3 Access Roads Wellfield road 32.2 (ML-portion) Mine road 25.2 Site southern access road 30.2 Total ML land disturbance (on-lease infrastructure) 1,776.4 Western access road 199.4 Electricity transmission line (including access track) 80.1 Total Western Infrastructure Corridor land disturbance 279.5 Radial Wellfield North-eastern Arm infrastructure including wellfield pipeline corridors, 66.4 pumping infrastructure and wellfields and access tracks (PI2, PI6, PI7, PI10, PI11, PI12) Total Eastern Radial Wellfield land disturbance 66.4 Radial Wellfield Southern Arm infrastructure including wellfield pipeline corridors, pumping 6.0 infrastructure and wellfields and access tracks (PS8, PS10, PS12, PI13) Southern Access Road 7.3 Total Southern Access and Radial Wellfield land disturbance 13.3 Wellfield infrastructure including Project Wellfield pipeline corridors, staging tanks and well 258.2 disturbance Approximately 17 borrow pits established along the length of the Western Infrastructure 22.5 Corridor for road construction and maintenance Rail siding and 10 km private haul road 31.5 Total 2,923.95
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2.2 Alternatives to Taking the Proposed Action
No alternatives proposed.
2.3 Alternative Locations, Time Frames or Activities That Form Part of the Referred Action
Where applicable, alternative activities (or options) that form part of the referred action are described within Section 2.1. Options associated with the location of the CTP are discussed in Section 2.1.5.
2.4 Context, planning framework and state/local government requirements
Approval under the Mining Act is the primary state statutory approval required for the proposed Mining Lease and associated Miscellaneous Purposes Licences. Further information regarding this assessment process is provided in Section 2.5.
2.4.1 Development Plan Zoning
The area comprising the proposed tenements is zoned as Remote Area (Far North) in the Development Plan - Land Not within a Council Area Eyre, Far North, Riverland and Whyalla. This zone encompasses a significant proportion of the remote areas of the State, and includes land rich in minerals, fossil fuels and groundwater. It contains extensive areas that are of cultural significance to Indigenous people and many areas of non-Indigenous heritage. Established pastoral and grazing activities take place within this zone and significant growth and development in the mining industry is anticipated.
The Remote Area zone envisages a range of development, including industry associated with mining, prescribed mining activities, pastoral, grazing and farming activities and mining settlements.
The zone and policy intent for the remote Far North seeks to guide sustainable growth and development of mining-related activities and the development of new mining-related settlements to facilitate growth.
There are no identified plans for significant changes in existing land use by other parties within the area surrounding the proposed tenements.
2.4.2 Environmental Protection Act
The Environment Protection Act 1993 (SA) (EP Act) has been established to promote ecologically sustainable development through the use, development and protection of the environment. Section 25 of the EP Act establishes a general environmental duty, requiring that activities that pollute or might pollute the environment must not be undertaken unless all reasonable and practicable measures to minimise harm are implemented.
Section 36 of the EP Act requires that works to construct a building or structure for use for an activity of environmental significance must not be undertaken without an environmental authorisation.
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2.4.3 Radiation Protection and Control Act
In South Australia, the primary legislation for radiation control is the Radiation Protection and Control Act 1982 (SA) (the Act) and associated legislation. The Act and regulations refer to permitting processes and the development of a radiation management plan and a radioactive waste management plan. The laws also enact various ARPANSA codes of practice. The operation will be assessed for potential licence or registration under the RPC Act. Conditions attached to the licence or registration require the licensee to ensure the operations are conducted in a manner that protects people and the environment from the harmful effects of ionizing radiation. Should the operation require an authorisation, the operation may be required to develop a Radiation Management Plan and Radioactive Waste Management Plan endorsed by the South Australian Environmental Protection Authority.
2.4.4 Native Vegetation Act
The Native Vegetation Act 1991 (SA) (NV Act) controls the clearance of native vegetation and requires OZ Minerals to provide a Significant Environmental Benefit (SEB) for any native vegetation clearance. The approach to native vegetation management and the provision of an SEB is further described in Section 2.1.13.
2.4.5 Other Legislative Requirements
To ensure that draft outcomes related to the proposed activities establish a foundation for operational efficiency, other legislation is taken into account through the assessment methodology for the Mining Lease Proposal. Incorporating the awareness of and demonstrated compliance with requirements from other relevant legislation into the assessment supports the development of the PEPR and allows an all- inclusive operational document. The other relevant legislation is: Aboriginal Heritage Act 1988 (SA) Dangerous Substances Act 1979 (SA) Explosives Act 1936 (SA) Natural Resources Management Act 2004 (SA) Fire and Emergency Services Act 2005 (SA) Road Traffic Act 1961 (SA) Public and Environmental Health Act 1987 (SA) Civil Aviation Act 1988 (Cth) Electricity Act 1996 (SA).
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2.5 Environmental Impact Assessments Under Commonwealth, State or Territory Legislation
As outlined in Section 1.11 of this referral, the proposed action requires approval under the Mining Act, including submission of a Mining Lease Proposal and Miscellaneous Purposes Licence Management Plans. The Mining Act regulates and controls mining operations in South Australia and is regulated by DSD on behalf of the Minister for Mineral Resources and Energy (Minister). The Mining Act provides a two-stage assessment and approval process to enable mining operations to commence as shown in Figure 2.19. The first is a detailed environmental impact assessment of the Project, which results in the granting or refusal of a tenement. Once a tenement is granted, the tenement holder must have an approved Program for Environment Protection and Rehabilitation (PEPR) in place to enable operations to commence.
The MLP assessment process is a recognised single assessment process agreed to under the bilateral agreement, which could be used to assess the Project if it is a controlled action.
The assessment framework undertaken within the MLP draws on the requirements of ISO 14001, State and Federal regulation and internationally recognised frameworks such as those established by the International Finance Corporation of the World Bank Group. The assessment methodology is compliant with Ministerial Determination 006 (DSD, 2015a) and Ministerial Guideline MG2a (DSD, 2015b), to ensure it meets the requirements of the Mining Act and associated regulations and also aligns with the Significant Impact Guidelines established under the EPBC Act.
2.6 Public Consultation
OZ Minerals has undertaken a robust stakeholder identification and analysis process to understand the differing levels of potential impact and affect (direct or indirect) and interest that may arise across different stakeholder groups, and has used this to inform how engagement has been undertaken with all stakeholders (see Table 2.23).
Table 2.23: Project Stakeholders Stakeholder Group Description Pastoral stations Pernatty Pastoral Lease surrounding the Project Arcoona Pastoral Lease lease area Bosworth Pastoral Lease Oakden Hills Pastoral Lease South Gap Pastoral Lease Kootaberra Pastoral Lease Project Site Traditional Kokatha People Owners Kokatha Aboriginal Corporation Local Community Port Augusta, Port Pirie, Whyalla, Woomera, Roxby Downs, Andamooka Members Local Councils and Port Augusta City Council Representative of Port Pirie Regional Council Unincorporated Areas Whyalla City Council
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Stakeholder Group Description Municipal Council of Roxby Downs Andamooka Progress and Miners Association Woomera Board Outback Communities Authority Regional Development Australia – Far North Regional Development Australia – Whyalla and Eyre Regional Development Australia – Yorke and Mid North South Australian Arid Lands Natural Resources Management Board Upper Spencer Gulf Common Purpose Group Whyalla Economic Development Board / Whyalla Advisory Taskforce Local Business Port Augusta, Port Pirie, Whyalla, Woomera, Roxby Downs, Andamooka Community and Industry Global Maintenance Upper Spencer Gulf Government of South Department of State Development Australia Department of Environment, Water and Natural Resources Environment Protection Authority Department of The Premier and Cabinet Aboriginal Affairs and Reconciliation (situated within DSD) Department for Planning, Transport and Infrastructure Resources and Energy Sector Infrastructure Council SafeWorkSA Local / Regional Service Royal Flying Doctor Service Providers Local community organisations, such as Roxby Downs Community Club Emergency services such as police, ambulance, fire service and SES Australian Government Department of Environment and Energy Department of Defence Department of Industry, Innovation and Science Department of Infrastructure and Regional Development OZ Minerals Limited Employees, contractors Investment Community Investors, financiers and insurers Non-Government Conservation Council of SA Organisations Service Providers Providers of services such as water, power and telecommunications South Australian South Australian based service provides Businesses Community South Australian Chamber of Mines and Energy Other Community Tourists Members Media Television, print, internet.
Carrapateena Project / March 2017 Page 74 of 172 Preparation of: Mining Lease application (mining proposal); Miscellaneous Purposes Licence application (management plan) MD006 and Mining Regulations 2011
Statutory public consultation Mining Act, sections 35A and 53(2)
STAGE 1 Lease/licence Application Applicant response to public submissions Mining Act, Parts 6 and 8
Department assessment, public submissions and applicant response to submissions
Lease/licence Lease/licence granted application refused
If granted
Community engagement
STAGE 2 Program for Environment Protection PEPR (includes native vegetation SEB) and bond and Rehabilitation Mining Act, Part 10A
Other government authorisations (e.g. EPA licensing)
Figure 2.19: Mining Act Two-Stage Assessment Process
CARRAPATEENA PROJECT Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
Meaningful stakeholder participation in the conceptualisation and ongoing design of the Carrapateena Project was central to the consultation sessions held across Government and the broader Upper Spencer Gulf and Outback Communities Regions in September, October and November of 2016. The approach to engagement combines lessons learned from local histories, local experience and operational experience in the region, and provides an opportunity for OZ Minerals to listen and align to what the community values.
OZ Minerals is committed to South Australia and the Project has and will continue to be developed with a focus on building trust and relationships with stakeholders. OZ Minerals will continue to work collaboratively with stakeholders to understand what is important to them.
Economic and employment certainty for the Upper Spencer Gulf and Outback Communities is seen as one of the most critical focus points for the community. OZ Minerals acknowledges this feedback and will continue working to bring opportunities to the local region. The Carrapateena Project is aligned with the strategic priorities of the Government of South Australia and the regional development priorities of local and regional governing agencies, including the Outback Communities Authority (OCA), Regional Development Australia Far North (RDAFN) and Local Councils within the Upper Spencer Gulf region. This alignment provides a platform from which to continue to create opportunities for local people and business through collaboration and partnership.
The area within which the tenements are proposed is subject to the Kokatha People (Part A) Native Title Determination (National Native Title Tribunal Number (NNTT) SCD2014/004) as shown in Figure 1.4. The Kokatha Aboriginal Corporation (KAC) is the Registered Native Title Body Corporate who acts as an agent for the Kokatha People in relation to their native title rights and interests.
OZ Minerals and KAC have a Native Title Mining Agreement (NTMA) in place for RL 127 (registered on 5 March 2013), and has established a Partnering Agreement (Nganampa palyanku kanyintjaku ‘Keeping the future good for all of us’) to inform the relationship between Kokatha and OZ Minerals throughout and beyond the development of the Carrapateena Project.
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2.7 A Staged Development or Component of a Larger Project
The proposed action forms part of a larger action that includes existing tenements, the proposed tenements and potential future tenements. All of the key Project elements across these tenements have been incorporated into the Project description for the purposes of assessing the potential cumulative and worst case environmental impacts that may occur. The larger action including the potential future tenements are summarised in the Table 2.24.
Table 2.24: Existing Tenements, Proposed Tenements and Potential Future Tenements
Proposed Tenement Key Project Elements
Mining Lease Carrapateena Mining Lease Mining, processing, tailings storage facility, water supply and ancillary infrastructure
Miscellaneous Purposes Licences Eastern Radial Wellfield MPL Water supply (east)
Southern Access Road and Radial Access road and water supply (south) Wellfield MPL Western Infrastructure Corridor Transmission line, access road and common services MPL Airstrip, Accommodation and Site access, logistics and accommodation Associated Infrastructure (Currently Under State Assessment)
Existing Tenement Key Project Elements Retention Lease Advanced exploration works
Potential Future Tenements Key Project Elements Future Regional Project Wellfield Wellfield infrastructure including Project Wellfield pipeline corridors, MPL staging tanks and well disturbance Future Infrastructure Corridor Approximately 17 borrow pits established along the length of the Borrow Pit EMLs Infrastructure Corridor for road construction and maintenance Future Rail Siding and Haul Road Rail siding and 10 km private haul road MPL
As mentioned in Section 2.1.3, future expansion opportunities exist (i.e. the Saddle Deposit and Fremantle Doctor). If these opportunities arise, their impacts would be re-assessed against the EPBC Act and this referral to determine whether a new referral would be required.
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3 DESCRIPTION OF ENVIRONMENT AND LIKELY IMPACTS
A search of the Protected Matters Search Tool (PMST) was undertaken in February 2017, encapsulating the area described in Section 1.2 with an additional conservative boundary including the potential future tenements. The Protected Matters Search Tool report generated is provided in Table 3.1, and Appendix 1 EPBC Act Protected Matters Report, and discussed in the following sections of this chapter.
Table 3.1: Results from MNES Search Proposed Tenements
Identified within Search area (5 km buffer) EPBC Act Protected Matters Report Search Area World Heritage Properties None National Heritage Properties None Wetlands of International Significance None Great Barrier Reef Marine Park None Commonwealth Marine Areas None Threatened Ecological Communities None Threatened Species 5 Migratory Species 6 Commonwealth Lands 1 Commonwealth Heritage Places None Listed Marine Species 10 Whales and other Cetaceans None Critical Habitats None Commonwealth Reserves None State and Territory Reserves 1 Regional Forest Agreements None Invasive Species 12 Nationally Important Wetlands 1
Key Ecological Features (Marine) None
3.1 Matters of National Environmental Significance
3.1.1 World Heritage Properties
There are no World Heritage places within 500 km of the Project. Consequently, the proposed action will not have a significant impact on World Heritage values.
3.1.2 National Heritage Places
The closest National Heritage place is the Ediacara Fossil Site situated at Nilpena, approximately 72 km west of the Project. Consequently, the proposed action will not have a significant impact on National Heritage values.
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3.1.3 Wetlands of International Importance (Declared Ramsar Wetlands)
There are no Wetlands of International Importance in proximity to the site, including downstream from the proposed action site. Consequently, the proposed action will not have a significant impact on the ecological character of a Ramsar wetland.
3.1.4 Listed Threatened Species
The PMST indicated that five listed threatened species might occur within the Project Area in all tenements, but no threatened ecological communities. Desktop assessments undertaken for this referral and for baseline ecological assessments provided in Appendix 2 Ecological Baseline Assessment provides a sound basis for determining the presence of species in the area of the proposed action. Further detail of site survey activities undertaken to date is provided within Appendix 2 Ecological Baseline Assessment.
An intensive baseline survey was first undertaken in the Carrapateena regional area in 2007. Land assessed extended east to west from the western boundaries of Lake Torrens and Andamooka Ranges to the Stuart Highway. North to south, the survey extent ranged from Arcoona Lake and Bosworth Creek, south to Horatio Lagoon.
Bi-annual autumn and spring ecological terrestrial flora and fauna field surveys have been undertaken within the Regional Study Area since 2012. These surveys focused on extending baseline knowledge of flora associations and species, terrestrial mammals, reptiles and avifauna that utilise the Project Area. These surveys occur every autumn and spring, allowing for seasonal variation in species composition.
The field surveys focussed on identification of key terrestrial habitats and sensitive areas, flora and fauna species, vegetation communities and national or State listed species. The ecological studies undertaken were based on the following: Background literature reviews to establish the regional context of the site Identification of key habitat sites and sensitive ecological areas Baseline flora and fauna surveys Implementation of monitoring sites conducted bi-annually Vegetation mapping Targeted threatened species surveys.
Surveys were undertaken with approval from the South Australian Department of Environment, Water and Natural Resources (DEWNR), under a Permit to Undertake Scientific Research and utilising the standard DEWNR biological survey methods (Owens, 2000; Heard and Channon, 1997). Information regarding threatened species was sourced from the Biological Data Base of South Australia (BDSA) and the Department of the Environment and Energy’s Species Profile and Threats Database (SPRAT) (DoEE, 2017).
Table 3.2 summarises the Threatened species identified in the Protected Matters Search Tool including a description of the species, preferred habitat types and the likelihood of occurrence within the Project Area based on the extensive survey efforts undertaken to date and as detailed in Appendix 2 Ecological Baseline Assessment.
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Table 3.2: Threatened Species Identified by EPBC Protected Matters Search Tool or in Ecological Surveys
Species Name Conser- Identified Likelihood of and Common vation Habitat Preference / Description in PMST Occurrence2 Name Status1 Fauna Amytornis VU Favours chenopod shrublands, especially those supporting Y Unlikely modestus Maireana spp. and Atriplex spp. Prefers areas along drainage (Thick-billed lines where shrubs are taller and thicker. Generally, only a small Grasswren) number of patches within the Project Area were identified as being potentially suitable habitat; mainly along the south- western end of Salt Creek. Calidris CE, Mi, Mainly occur on intertidal mudflats in sheltered coastal areas Y Unlikely ferruginea Ma such as estuaries, bays, inlets and lagoons, and around non- (Curlew tidal swamps, lakes and lagoons near the coast, and ponds in Sandpiper) saltworks and sewage farms. They have also been recorded inland, though less often, including around ephemeral and permanent lakes, dams, waterholes and bore drains, usually with bare edges of mud or sand. They occur in both fresh and brackish waters. Occasionally they are recorded around floodwaters. Pezoporus EN, Mi Long thought extinct, this species historically occupied much Y Unlikely occidentalis of semi-arid and arid Australia. Habitat appears to be mainly (Night Parrot) open grasslands consisting principally of Triodia in stony or sandy environments. Present distribution of the species is unknown, with the only confirmed location being in South- western Queensland. The species is believed to be highly nomadic, moving into areas with preferred habitat when resources are good. Pseudomys VU Primarily found in gibber (stone-covered) plains and mid Y Present australis slopes with boulders, small stones and gilgais. Primary habitat (Plains Mouse is considered the drainage channels and depressions with or Plains Rat) deep friable cracking clays. These habitats are considered best able to collect water from even minor falls of rain. Secondary habitats are associated with gilgais and minor drainage areas with low perennial chenopod shrublands and heavier cracking clays. In years of very good rainfall, this species occur on adjoining sandy plains. During poor conditions, core refuge areas may occur on low-lying gilgais and watercourses of gibber plains. While the Regional Study Area provides suitable habitat for Plains mouse, it is considered an area where they disperse to rather than critical refuge habitat. It is likely that in times of irruption events, the dominant habitats have mass dispersal in order to satisfy food requirements, and areas such as the Project Area then become home to individuals on short-term basis. Flora Frankenia EN The species is a low, mat-forming perennial shrub on lower Y Unlikely plicata slopes of hills and in small run-off channels. Most confirmed (Sea-heath) records of this species are from the Breakaways. 1 Conservation Codes: CE: Critically Endangered. EN: Endangered. VU: Vulnerable. R: Rare. Mi: Migratory, Ma: Marine 2 Likelihood Codes: Unlikely: Project Area does not contain habitat and/or is outside of the species’ current known distribution and the species has not been recorded within the Project Area to date. Possible: Project Area contains preferred habitat that may support a population of the species, however the species has not been recorded within the Project Area to date Present: Project Area contains preferred habitat that may support a population of the species, and the species has been observed within the Project Area during ecological surveys.
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Amytornis modestus (Thick-billed Grasswren) Habitat Summary
In South Australia, Thick-billed Grasswren (Amytornis modestus) are widespread from the Lake Frome basin, west to the eastern Lake Torrens basin, northwest to near Leigh Creek and Marree, along the southern and western fringes of the Lake Eyre Basin (including the Davenport Ranges and near William Creek), and west to the Coober Pedy region (Badman, 1989; Brandle, 1998; Higgins et al. 2001; DoE, 2016). The species has also been recorded at two sites northwest of Lake Eyre (Brandle, 1998).
The Thick-billed Grasswren occurs in chenopod shrublands in the arid and semi-arid zones, especially shrublands dominated by Maireana spp. (Bluebush) and Atriplex spp. (Saltbush), sometimes with widely scattered trees (Higgins et al., 2001; in DoE, 2016). The Grasswren seemingly favours areas on drainage lines where Saltbush and Bluebush shrubs are taller and thicker. Other studies have also indicated that the species persists in low chenopod shrublands, particularly where water courses are present (NPWS, 2002) and/or in areas dominated by Atriplex spp. and Maireana spp (Garnett and Crowley, 2000), which is prevalent in the Project Area.
A detailed habitat assessment was undertaken across the Project Area in autumn 2013 and only a small number of patches of Maireana aphylla of the preferred height and density were identified as being potentially suitable habitat; mainly along the southwestern end of Salt Creek. They were however very small, and isolated, with no other preferred vegetation patches within close proximity. This area is outside of the proposed Project Area and is not expected to be affected by the proposed Project. There were no Thick-billed Grasswren found during ecological surveys undertaken to date (2007 – 2016) and there are no BDBSA records for this species within the Project Area. The nearest observation of the species was approximately 65 km from the Project Area.
Therefore, it is considered unlikely that the Project Area supports an important population of the Thick- billed Grasswren. It is possible that the species will extend its range into the Project Area after exceptional periods of rain that would stimulate plant growth and increase breeding of the species. Under these conditions, habitat would be widely available across the region.
Nature and Extent of Likely Impact
Because of the lack of preferred habitat within the Project Area, there is expected to be no change in area, fragmentation, modification, removal or isolation of intact critical habitat of the species. The species has not historically been observed within the Project Area, and is considered unlikely to support populations and therefore there is unlikely to be any disruption to breeding cycles, health of populations or recovery of populations in the Project Area as a result of Project activities. Further, there is not expected to be a change in the abundance of invasive flora or fauna as a result of the Project that would have a region-wide impact on the species.
It is therefore, unlikely that there will be a significant impact on the population size or viability of the Thick-billed Grasswren as a result of the Project.
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Calidris ferruginea (Curlew Sandpiper) Habitat Summary
The Curlew Sandpiper (Calidris ferruginea) is a small wader that breeds on the tundra of Arctic Siberia. It is strongly migratory, wintering mainly in Africa, but also in south and southeast Asia and in Australasia. It is a vagrant to North America and a common summer migrant from northeastern Siberia and Alaska. It is found in many Australian coastal sites and may be seen inland in suitable habitats. It is most common in the far southeast and north-west of Australia, Africa, across southern Asia to Indonesia, New Guinea and in New Zealand.
The Curlew Sandpiper occurs around the coast of Australia however, may also be found inland in smaller numbers. Their breeding range is restricted to the Arctic or northern Siberia; the species does not breed in Australia (Higgins & Davies 1996). Substantial numbers of curlew sandpipers remain in northern Australia during the non-breading season while others stop over before migrating to southern Australia. Some pass through northeast South Australia during migration.
In South Australia, curlew sandpipers are widespread in the coastal and sub-coastal areas of Streaky Bay and occasionally occur in inland areas south of the Murray River. They occur in sheltered coastal areas, non-tidal swamps, lakes and lagoons near the coast and artificial ponds such as salt lakes and sewage farms. They can occur in fresh or brackish waters. Less often they are recorded inland around ephemeral and permanent lakes, dams, waterholes and bore drains where bares areas of much or sand are present (Higgins & Davies 1996).
Migratory species such as the Curlew Sandpiper are unlikely to be present in the proposed Project Area due to the absence of significant wetland areas favourable to this species. It has not been identified in ecological surveys within the Project Area.
Nature and Extent of Likely Impact
Because of the lack of preferred wetland habitat within the Project Area, there is expected to be no change in area, fragmentation, modification, removal or isolation of intact critical habitat of the species. The species has not historically been observed within the Project Area, and is considered unlikely to support populations and therefore there is unlikely to be any disruption to breeding cycles, health of populations or recovery of populations in the Project Area as a result of Project activities. Further, there is not expected to be a change in the abundance of invasive flora or fauna as a result of the Project that would have a region-wide impact on the species.
The creation of evaporation ponds, tailings dam and decant pond may make Carrapateena more attractive to the species. The impact of the creation of these liquid bodies is detailed in the ‘Nature and Extent of Likely Impact on Migratory Shorebird Species’.
It is unlikely that there will be a significant impact on the population size or viability of the Curlew Sandpiper as a result of the Project.
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Pezoporus occidentalis (Night Parrot) Habitat Summary
The Night Parrot is a medium-sized, nocturnal, ground-feeding parrot growing 22 - 25 cm long. The only recorded weight is a trapped female that weighed 104 g (Murphy 2015a). Adults are mostly bright- green with extensive black and yellow markings, including streaks, spots and bars and a yellow belly (Higgins, 1999). The night parrot characteristically makes a ‘ding-ding’ call similar to that of a bell miner (Manorina melanophrys), a short frog-like ‘grieet’, and other three and four-note calls (Murphy 2015, Murphy 2016).
The current distribution of the Night Parrot is not known. Historic records and observations are scanty and anecdotal with few substantiated records since 1935. There are accepted historical records from remote arid and semi-arid inland regions of Western Australia, Northern Territory, South Australia and Queensland (Higgins, 1999). It is possible that the Night Parrot will continue to occur throughout much of this range (Garnett et al., 1993; Blyth, 1996; Garnett & Crowley, 2000; Garnett et al. 2011). Despite numerous unverified sightings, several dedicated searches and public campaigns there have been only two areas (western Queensland and the Pilbara in Western Australia) where reliable records indicate that populations may persist. Sometime prior to 2013, a population was located in southwestern Queensland by naturalist John Young (Koch 2013). An unknown number (suspected to be small) of individuals were detected every month during a survey between August 2013 and January 2016 (Murphy 2016). The location of this area has not been identified in order to protect the species.
Most habitat records are of Triodia (Spinifex) grasslands and/or chenopod shrublands (Garnett et. al., 2011) in the arid and semi-arid zones, and Higgins (1999) listed Astrebla spp. (Mitchell grass), shrubby samphire and chenopod associations, scattered trees and shrubs, Acacia aneura (Mulga) woodland, treeless areas and bare gibber as associated with sightings of the species. Roosting and nesting sites are consistently reported as within clumps of dense vegetation, primarily old and large Spinifex clumps, but sometimes other vegetation types (Higgins 1999, Murphy 2015).
Eating spinifex seeds, Night Parrots usually feed on the ground at night and is believed to be highly nomadic, moving into areas with preferred habitat when resources are good. As such, the main potential threats to the Night Parrot include predation by feral cats (Felis catus) and foxes (Vulpes vulpes). Additional threats include changes in fire regimes; competition for food and degradation of habitat by livestock and feral herbivores; reduced availability of water due to consumption by camels (Camelus dromedarius) and livestock; habitat degradation by rabbits (Oryctolagus cuniculus) and goats (Capra hircus); and reduced maintenance of waterholes by Indigenous communities (Blyth, 1996; Garnett & Crowley, 2000).
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Nature and Extent of Likely Impact
The species has not historically been observed within the Project Area, and is considered unlikely to support a population. Therefore, there is unlikely to be any disruption to breeding cycles, health of populations or recovery of populations in the Project Area as a result of Project activities. Further, there is not expected to be a change in the abundance of invasive flora or fauna because of the Project that would have a region-wide impact on the species.
There will be removal of chenopod shrubland, which has been cited as supporting Night Parrots, however, given the species has not historically been observed within the Project Area, it is not expected that there will be a change in area, fragmentation, modification, removal or isolation of intact critical habitat for the species.
It is considered unlikely that there will be a significant impact on the population size or viability of the Night Parrot as a result of the Project.
Pseudomys australis (Plains Rat or Plains Mouse) Habitat Summary
The Plains Mouse (Pseudomys australis) is restricted to the gibber plains of the Lake Eyre Basin in northern South Australia. The present distribution of the Plains Rat appears to be restricted to a north- south band of stony plain habitat west of Lake Eyre, which extends for approximately 700 km (Brandle et al 1999). Moseby (2012) identifies the Arcoona Tableland including Pernatty Station as an ’area of occupancy’ within this distribution band and the southern-most extent of the suitable habitat. The ‘Draft Plains Mouse Recovery Plan’ by Moseby (2012) provides the following summary of the current Plains Mouse distribution:
The species tends to be recorded in cracking clay areas associated with minor drainage features and depressions in gibber stony plains (Brandle 1998). It is generally accepted that the presence of cracking clays is more critical habitat than the type or structure of vegetation. The species has been recorded in several vegetation communities, including Old-man Saltbush (Atriplex nummularia) / Plains Lantern- bush (Abutilon halophilum) low very open shrubland, Tangled Bindyi (Sclerolaena divaricata) / Cane- grass (Eragrostis australasica) / Bladder Saltbush (Atriplex vesicaria) low open shrubland, Cotton-bush (Maireana aphylla) / Bristly Love-grass (Eragrostis setifolia) / Barley Mitchell-grass (Astrebla pectinata) / Bladder Saltbush (Atriplex vesicaria) low very open shrubland and Coolibah (Eucalyptus coolabah) low woodland (Brandle, 1998).
The Plains Mouse proliferates in large numbers during optimal seasonal conditions, due to its ‘boom and bust’ population dynamics (Moseby, 2012). During times of low resources, this species contracts to refuge sites such as Cane-grass gilgais and cracking clay areas. Then during natural irruptions after significant rainfall events, the Plains Rat temporarily inhabits a variety of habitat types (Moseby, 2012).
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Existing threats to the Plains Mouse include predation from exotic species and intensive stock grazing. Habitat degradation from stock is a particular threat to the species in gilgai habitats because they may remove vegetative cover, compact ‘puffy’ cracking soils and trample burrows (Moseby, 2012).
Plains Mice have been captured within the Project Area during the bi-annual ecology surveys. Numbers have fluctuated based on the environmental conditions, which is expected. During the autumn 2013 survey of the Carrapateena Project Area, a detailed Plains Rat habitat assessment was undertaken across the Project Area. The habitat analysis included small-scale ground-truthing of gilgais, a known preferred habitat type, within the Project Area. Based on the habitat analysis undertaken, approximately 25% of the area is suitable ‘refuge’ habitat for the Plains Mouse (clay gilgais). The clay gilgais are spread over the entire Project Area, however appear to be more common on flat areas and are absent from creeklines and steep hills sides.
Nature and Extent of Likely Impact
Part of the disturbance footprint associated with the Project is suitable habitat for the Plain Mouse (see Figure 3.1). Extensive areas of Plains Mouse habitat have been mapped outside the proposed tenements, and also within the tenements but outside of the disturbance area. Similar habitat mapping beyond the Project Area has not been undertaken within the broader region however, as the land system extends well outside the Project Area, it can be expected that the Plains Mice occur abundantly throughout the region.
Impacts to cracking clay habitat from changes to surface water flow across the site will be localised. Experience at other sites indicates the species appears to exist amongst disturbance including mine camps and disturbance associated with vehicle usage. The Plains Mouse may be impacted by an increase in predators, such as feral cats and foxes; however, no increase in abundance of these invasive species is expected. Due to the extent of the mapped habitat available in the regional area as well as the expectation that this far exceeds the known or mapped distribution, the proposed action will not significantly reduce or fragment the available habitat.
It is likely that the impact of the clearance of potential habitat will have a local effect only. In periods of abundant resources, Plains Mice breed very quickly, are highly mobile when in large numbers and can occupy a range of habitat types. The overall impact to the Plains Mouse from the Project is likely to be local. Based on the current understanding of the species to date, it is considered that removing some potential habitat for this species associated with the mine infrastructure footprint is unlikely to have a significant regional impact to the population. When climatic conditions are favourable, the population of Plains Mouse has been shown to boom and disperse across the landscape. Experience at other sites, such as Prominent Hill, indicates the species appears to exist within the vicinity of mining operations, which indicates that an impact is unlikely beyond the immediate infrastructure and/or operations.
Consequently, the proposed action is not considered to have a significant impact on the species.
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Frankenia plicata (Sea-heath) Habitat Summary
Sea-heath, listed as endangered under the EPBC Act, was identified within the BDBSA search records 45 km north of the Project Area. The species is a low, mat-forming perennial shrub on lower slopes of hills and in small run-off channels. Most confirmed records of this species are from the Breakaways. Additionally, the majority of state listed species for Frankenia genus are ephemeral species. This species has not been identified within the Project Area during the surveys undertaken to date.
Nature and Extent of Likely Impact
Sea-heath has not been recorded within 45 km of the Project Area and would therefore not restrict the available habitat for this species or adversely impact any known populations.
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3.1.5 Listed Migratory Species
The PMST indicated six listed migratory species may occur within the Project Area, including the Night Parrot and Curlew Sandpiper (previously described in Section 3.1.4 and not repeated here). A further three migratory species beyond those identified in the PMST have been recorded in ecological surveys within the Project Area. This section groups the species by aerial foragers, wagtails, migratory waders (shorebirds and shoreline and terrestrial habitats) as described in Table 3.3.
Table 3.3: Migratory Species Identified by the EPBC PMST or in Ecological Surveys
Conser- Likelihood In Species vation Description of PMST Status1 Occurrence2
Aerial foragers
Apus pacificus Mi, Ma Asian origin - species is aerial during its stay in Australia. Y Possible (Fork-tailed Swift) Wagtails
Motacilla flava Mi, Ma Breeds in Europe and Alaska before south. Regular summer Y Unlikely (Yellow Wagtail) visitor to northern Australia. Has been recorded in all states. Prefers grasslands and swamps as well as Saltmarshes. Motacilla cinera Mi, Ma A migratory species found within Europe, Asia and North Y Unlikely (Grey Wagtail America, has been recorded in Australia infrequently. Most of these records are from northern Australia. Migratory waders (shoreline)
Actitis hypoleuco Mi, Ma Found in coastal or inland wetlands, both saline and fresh. It is N Present (Common found mainly on muddy edges or rocky shores. During the Sandpiper) breeding season in the northern hemisphere, it prefers freshwater lakes and shallow rivers. Calidris acuminata Mi, Ma Prefers the grassy edges of shallow inland freshwater wetlands. N Present (Sharp-tailed It is also found around swage farms, flooded fields, mudflats, Sandpiper) mangroves, rocky shores and beaches. Breeds in Siberia.
Calidris ferruginea CE, Mi, Described in Table 3.2. Y Unlikely (Curlew Sandpiper) Ma Calidris melanotos Mi, Ma Pectoral Sandpiper prefers shallow fresh to saline wetlands. N Present (Pectoral Sandpiper) The species is found at coastal lagoons, estuaries, bays, swamps, lakes, inundated grasslands, saltmarshes, river pools, creeks, floodplains and artificial wetlands. Tringa nebularia Mi, Ma Wide variety of inland wetlands and sheltered coastal habitats Y Present (Common of varying salinity such as sheltered coastal habitats, typically Greenshank, with large mudflats and saltmarsh, mangroves or seagrass. It Greenshank) will also use artificial wetlands, including sewage farms and saltworks dams, inundated rice crops and bores. Migratory waders (shoreline and terrestrial habitats)
Charadrius veredus Mi, Ma In non-breeding grounds, they prefer coastal habitats such as Y Unlikely (Oriental Plover, estuarine mudflats and sandbanks, on sandy or rocky ocean Oriental Dotterel) beaches or nearby reefs, or in near-coastal grasslands. 1 Conservation Codes: CE: Critically Endangered. EN: Endangered. VU: Vulnerable. R: Rare. Mi: Migratory, Ma: Marine 2 Likelihood Codes: Unlikely: Project Area does not contain habitat and/or is outside of the species’ current known distribution and the species has not been recorded within the Project Area to date. Possible: Project Area contains preferred habitat that may support a population of the species, however the species has not been recorded within the Project Area to date Present: Project Area contains preferred habitat that may support a population of the species, and the species has been observed within the Project Area during ecological surveys.
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Aerial Forgers
Apus pacificus (Fork-Tailed Swift) Habitat Summary
The Fork-tailed Swift is widespread from the Victorian border west to the Spencer Gulf. It is also common in coastal parts of Eyre Peninsula as far west as Franklin Island, off Streaky Bay and north to 32° south lattitude. There have been a few recently published records beyond these bounds, such as in Flinders Ranges and the Lake Eyre Drainage Basin from Billa Kallina Station, Lake Eyre South and Marree. Sightings have also been recorded north to Moorayepe and east to Innamincka and Moomba (Higgins, 1999).
This swift species breeds in Asia and occurs in southeastern Australia over summer. The species is aerial during its stay in Australia, inhabiting low to very high airspace over varied habitat, including rainforests through to semi-desert. Large flocks, which can sometimes reach thousands of birds, may occur occasionally as fly-overs within the Project Area. Due to their highly nomadic nature during their non- breeding period stay in Australia, they would rarely pass through the Western Infrastructure Corridor any more than a few times each year.
Nature and Extent of Likely Impact
As the species is aerial during its stay in Australia, the proposed action is not considered likely to have a significant impact on this species.
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Wagtails
Motacilla flava (Yellow Wagtail) / Motacilla cinera (Grey Wagtail) Habitat Summary
The Motacilla Wagtail is a migratory species that regularly reach the island of New Guinea but has been recorded with increasing frequency in northern Australia. Recordings occur during November to February, with few occurrences outside of these months.
Habitat requirements for the Yellow Wagtail are highly variable, but typically include open grassy flats near water. Habitats include open areas with low vegetation such as grasslands, airstrips, pastures, sports fields; damp open areas such as muddy or grassy edges of wetlands, rivers, irrigated farmland, dams, waterholes; sewage farms, sometimes utilise tidal mudflats and edges of mangroves. There is a low probability of this species occurring within the Project Area.
In their normal breeding range, Grey Wagtails are found across a variety of wetlands, especially watercourses, but also on the banks of lakes and marshes, as well as artificial wetlands such as sewage farms, reservoirs and fishponds. This association with water extends into non-breeding habitats with all confirmed Australian records being associated with water, especially creeks, rivers and waterfalls. On migration, they may forage on rocky tidal flats. The diet of the Grey Wagtail reflects its habitat with it feeding on a variety of insects as well as other small prey items such as molluscs, crustaceans and occasionally small fish and tadpoles. This species has a low likelihood of using the Project Area for habitat.
Throughout South Australia, there have only been seven recorded wagtail sightings (encompassing three species, Yellow, Grey and Citrine (M. citreola)) since 1982 (Berggy, 2003). There have been a number of sightings of Wagtails throughout Australia but the infrequency of these occurrences suggests there is no habitat of significance for these birds in the Project Area.
Nature and Extent of Likely Impact
It is considered unlikely that this species will occur on site. There is seemingly no significant habitat for these species on site and due to the infrequency of occurrences in South Australia, the proposed action is considered unlikely to have a significant impact on these species.
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Migratory Waders (Shoreline Habitat)
Actitis hypoleuco (Common Sandpiper) Habitat Summary
The Common Sandpiper is a species of migratory shorebird, which breeds from eastern Siberia to northern Japan, and migrates southward during the non-breeding season (Pizzey and Knight 2007). The majority of the non-breeding population is present within Southeast Asia and Australia. In Australia, the species is more common in the north and along the east coast (Pizzey and Knight 2007), with the species listed as rare in South Australia under the National Parks and Wildlife Act 1972.
The Common Sandpiper is often solitary or present as just a few individuals within Australia, where it is present in both coastal and inland wetlands, either saline or fresh (Bamford et al. 2008). The species will inhabit inland dams, where it will forage along the waterline, probing the mud for invertebrates. This species has been recorded within the Project Area.
Nature and Extent of Likely Impact
See page 96 Summary of Nature and Extent of Likely Impact on Listed Migratory Shorebird Species, discussed later in this section.
Calidris acuminata (Sharp-tailed Sandpiper) Habitat Summary
This is a migratory species, breeding in northern Siberia and moving in flocks of less than a thousand, to non-breeding areas south of the Equator. They begin moving south after breeding, and depart breeding areas by early September. They are mostly seen in Australia between August and April, with a small numbers of birds remaining in Australia over winter.
The Sharp-tailed Sandpiper spends the non-breeding season in Australia with the majority of the population migrating to Australia; mostly to the southeast however it is widespread in both inland and coastal locations and in both freshwater and saline habitats. Within South Australia, they range from locations in the eastern half of the state, generally east of a line from Streaky Bay. They may also extend into the north, to regions around Lake Eyre and west to areas such as Mintabie (Higgins and Davies, 1996). The species has been recorded within the Project Area.
The Sharp-tailed Sandpiper forages on seeds, worms, molluscs, crustaceans and insects.
Nature and Extent of Likely Impact
See page 96 Summary of Nature and Extent of Likely Impact on Listed Migratory Shorebird Species, discussed later in this section.
Calidris ferruginea (Curlew Sandpiper) Described in Section 3.1.4.
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Calidris melanotos (Pectoral Sandpiper) Habitat Summary
The Pectoral Sandpiper prefers shallow fresh to saline wetlands. The species is found at coastal lagoons, estuaries, bays, swamps, lakes, inundated grasslands, saltmarshes, river pools, creeks, floodplains and artificial wetlands. The Pectoral Sandpiper is omnivorous, consuming algae, seeds, crustaceans, arachnids and insects. While feeding, they move slowly, probing with rapid strokes. They walk slowly on grass fringing water (Higgins and Davies, 1996).
This is a migratory species, moving south after breeding and departs breeding areas by early September. It is mostly seen in Australia between August and April, however small numbers of birds remain in Australia over winter. In South Australia, the Pectoral Sandpiper is found mostly in the south-east, from north to the Murray River and west to Yorke Peninsula. The Pectoral Sandpiper has been observed within the Project Area.
Nature and Extent of Likely Impact
See page 96 Summary of Nature and Extent of Likely Impact on Listed Migratory Shorebird Species, discussed later in this section.
Tringa nebularia (Common Greenshank, Greenshank) Habitat Summary
The Common Greenshank is a heavily built, elegant wader with a long and slightly upturned bill and with legs which are long and yellowish-green. It is a migratory species, breeding in the Palaearctic and flying south, in a broad front, overland and along coasts to non-breeding areas for the boreal winter (Cramp & Simmons 1983). The species can be seen singly or in small to large flocks with some of these being into the hundreds across a wide variety of coastal and inland wetlands of varying salinity such as sheltered coastal habitats, typically with large mudflats and saltmarsh, mangroves or seagrass. It will also use artificial wetlands, including sewage farms and salt works dams, inundated rice crops and bores (Higgins & Davies 1996).
The species is common in South Australia, found throughout the area east of longitude 145° E, however very few records exist from the Flinders Ranges. The species prefers coastal habitats however, they also utilise a wide variety of inland wetlands of varying salinity, typically with large mudflats and Saltmarsh. They have also been observed using artificial wetlands, including sewage farms and saltworks dams, inundated rice crops and bores.
This species has been recorded within the Project Area, associated with an existing pastoral dam at the lower regions of Eliza Creek. However, few individuals would be present annually. There is a low likelihood of this species utilising the Project Area for critical habitat requirements.
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Nature and Extent of Likely Impact
See page 96 Summary of Nature and Extent of Likely Impact on Listed Migratory Shorebird Species, discussed later in this section.
Migratory Waders (Shoreline and Terrestrial Habitat)
Charadrius veredus (Oriental Plover, Oriental Dotterel) Habitat Summary
The Oriental Plover is a non-breeding visitor to Australia. The species occurs in both coastal and inland areas being found primarily in northern Australia. Most records are along the northwestern coast, between Exmouth Gulf and Derby in Western Australia, and there are records at a few scattered sites elsewhere, mainly along the northern coast, such as in the Top End, the Gulf of Carpentaria and on Cape York Peninsula. It is seldom recorded in southern Australia (Marchant & Higgins, 1993). There is no estimate of the extent of occurrence of the Oriental Plover in Australia.
Immediately after arriving in non-breeding grounds in northern Australia, Oriental Plovers spend a few weeks in coastal habitats such as estuarine mudflats and sandbanks, on sandy or rocky ocean beaches or nearby reefs, or in near-coastal grasslands, before dispersing further inland (Department of the Environment, 2013). Outside of this period, they generally inhabit flat, open, semi-arid or arid grasslands that are interspersed with hard, bare ground, such as claypans (Pedler, 1982).
Migratory species such as the Oriental Plover may use habitat such as the Pernatty Lagoon as infrequent visitors along the migration route however there are seldom records within South Australian itself and the likelihood of this species being observed within the Project Area are exceptionally low, having not been observed across 13 ecological surveys over 10 years.
Nature and Extent of Likely Impact
Habitat suitable for the Oriental Plover is likely to be cleared in the Project Area. However, areas where vegetation will be cleared, but without infrastructure covering the ground, such as roads and the airstrip, may still provide habitat for this species.
The impact of the creation of evaporation ponds, the TSF and associated Decant Dam, and other artificial surface waters are described on page 96 Summary of Nature and Extent of Likely Impact on Listed Migratory Shorebird Species, discussed later in this section.
Stilta Isabella (Australian Pratincole) Habitat Summary
The Australian Pranticole is long-legged wader with a slim build. Unlike other migratory wader species, the Australian Pranticole almost exclusively breeds in Australia (Bamford et al. 2008). Breeding occurs in the south of its range, where the species will nest in loose colonies. The breeding season typically ranges from September to December, however, may occur any time following good rains (Pizzey and Knight
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2007). The Australian Pranticole migrates northward during the non-breeding season (autumn to winter), with part of the population reaching Papua New Guinea and Indonesia (Bamford et al. 2008). It is unknown what proportion of the population migrates internationally during the non-breeding season.
The species is often located within areas of limited vegetation in close vicinity of water. In arid and semi- arid Australia, the species is present within open inland plains, including gibber, where there is sparse, low vegetation. The species has taken advantage of anthropogenic alteration of the landscape, with sightings often at dams, airfields, roadsides and stock routes (Maclean 1976; Pizzey and Knight 2007). The Australian Pranticole has occurred within the Project Area, with all but one record located at dams. The remaining record was an individual observed on a gibber plain with low chenopods, located within 1.5 km of a dam (EBS unpublished data). The use of dams within an arid landscape was also observed in northwestern New South Wales, where the species would forage along the water line, and bred within 1 km (Maclean 1976).
Nature and Extent of Likely Impact
See page 96 Summary of Nature and Extent of Likely Impact on Listed Migratory Shorebird Species, discussed later in this section.
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Summary of Nature and Extent of Likely Impact on Listed Migratory Shorebird Species The creation of significant areas of dewatered slurries of a mud-type consistency and open water as a result of the development of raw water and stormwater storage ponds, evaporation ponds and the TSF (and associated Decant Dam) may provide some attraction for migratory shorebird species.
Raw Water and Stormwater Storage Ponds Raw water from the Radial and Project Wellfields, and stormwater collected from site run-off and diversions will be directed to a series of storage ponds. This water will be saline-to-hypersaline with a neutral pH and levels of metals consistent with background surface water. These water bodies would be relatively small in area and would be located within the Processing Plant area, making them unattractive to migratory species. Further, it is considered that these water bodies will be generally unpalatable to avian fauna. In the unlikely event that migratory species are attracted to these storages their interaction is not considered likely to have a significant impact.
Evaporation Ponds Two evaporation ponds may be constructed, totalling 123 ha. Given the proposed size of the evaporation ponds and the shallow liquid depth, migratory waders may interact with these ponds. However, the proposed evaporation ponds would contain hypersaline water with a TDS concentration of approximately 180,000 mg/L, which would mean that the liquid is unpalatable for terrestrial and waterbirds. Foraging by migratory shorebirds within the evaporation ponds is likely to be limited to the presence of terrestrial insects on the shoreline as evaporation ponds are typically abiotic, meaning no invertebrates will be on offer within the sediment for consumption (Bamford et al. 2014). In the unlikely event that migratory species ingest water during operations, a comparison of heavy metal concentrations against relevant toxicity criteria indicates that no significant impacts are likely. Post- closure, the evaporation ponds would be decommissioned and rehabilitated.
Tailings Storage Facility and Decant Dam The TSF will create up to 510 ha of beach area containing consolidated and dewatered slurries of a mud- type consistency during operations. A supernatant pond on the TSF will drain to a Decant Dam with approximately 0.5 ha of open water nominally, and up to 20 ha following large rainfall events. Of the migratory species only shorebirds are likely to be attracted to the TSF beach during operations. The decant dam storage area, dependent on depth, may provide habitat for waterfowl during operations.
During operations, the TSF supernatant water and associated Decant Dam water will contain lower concentrations of heavy metals than the evaporation ponds at levels that will not significantly impact migratory species. The pH is expected to be relatively neutral (pH 6-7) with a TDS concentration predicted to be 51,000 mg/L. Post closure there will be no supernatant water or decant dam and as such there are not expected to be any long term impacts to migratory species.
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Marine Species Fourteen marine species were highlighted in the EPBC Protected Matters Search report; however six of those species are also included in the Threatened and/or Migratory Species categories hence only eight are discussed in this section. The habitat preferences of each species present are provided in Table 3.4.
Table 3.4: Marine Species Identified by the EPBC Protected Matters Search Tool or in Ecological Surveys
Species Name Conservation Identified Likelihood of and Common Habitat Preference / Description Status1 in PMST Occurrence2 Name Marine
Apus pacificus Mi, Ma Asian origin - species is aerial during its stay in Y Possible (Fork-tailed Australia. Swift) Ardea alba Ma Floodwaters, rivers, wetlands, mudflats. Y Possible (Great Egret, White Egret) Ardea ibis Ma Grasslands, woodlands and wetlands with a preference Y Possible (Cattle Egret) for moist areas with tall grass, or shallow open wetlands, and wetland margins. Calidris CE, Mi, Ma Mainly occur on intertidal mudflats in sheltered coastal Y Unlikely ferruginea areas such as estuaries, bays, inlets and lagoons, and (Curlew around non-tidal swamps, lakes and lagoons near the Sandpiper) coast, and ponds in saltworks and sewage farms. They have also been recorded inland, though less often, including around ephemeral and permanent lakes, dams, waterholes and bore drains, usually with bare edges of mud or sand. They occur in both fresh and brackish waters. Occasionally they are recorded around floodwaters. Charadrius Mi, Ma In non-breeding grounds, they prefer coastal habitats Y Unlikely veredus such as estuarine mudflats and sandbanks, on sandy or (Oriental Plover, rocky ocean beaches or nearby reefs, or in near-coastal Oriental grasslands. Dotterel)
Larus Ma Found at both coastal and inland locations in a variety Y Possible novaehollandiae of habitats including artificial habitats. Breeds on small (Silver Gull) islands and points, mainly offshore, but also on freshwater and brackish lakes, and on causeways in saltpans. Merops ornatus Ma Open forests, woodlands, shrublands, and in various Y Present (Rainbow Bee- cleared or semi-cleared habitats, including farmland. eater) Often, but not always, located in close proximity to permanent water. Motacilla Mi, Ma Wide variety of wetlands, especially watercourses, but Y Unlikely cinerea also on the banks of lakes and marshes, as well as (Grey Wagtail) artificial wetlands such as sewage farms, reservoirs and fishponds. Motacilla flava Mi, Ma Highly variable habitat requirements, but typically Y Unlikely (Yellow Wagtail) include open grassy flats near water. Tringa nebularia Mi, Ma Wide variety of inland wetlands and sheltered coastal Y Present (Common habitats of varying salinity such as sheltered coastal Greenshank) habitats, typically with large mudflats and saltmarsh, mangroves or seagrass. t will also use artificial
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Species Name Conservation Identified Likelihood of and Common Habitat Preference / Description Status1 in PMST Occurrence2 Name wetlands, including sewage farms and saltworks dams, inundated rice crops and bores. Charadrius Ma Found in wetlands, especially in arid areas, and prefers N Present ruficapillus (Red- saline and brackish waters. capped Plover)
Cacomantis Ma The Pallid Cuckoo is the most widely distributed of the N Present pallidus (Pallid cuckoos and is found throughout Australia, and is Cuckoo) common in most open forests and woodlands, as well as cleared and cultivated open country. Chalcites basalis Ma The Horsfield's Bronze-Cuckoo is found in all regions, N Present (Horsfield’s found throughout much of South Australia, but not on Bronze-Cuckoo) the Nullarbor Plain. They w inhabit wooded habitats such as open and dry woodland and forest with a range of understoreys from grasses to shrubs or heath. Sometimes found near clearings and in recently logged or burnt forests. Found in farmland with some trees, orchards, vineyards and urban parks and gardens. Chlidonias Ma Prefers shallow terrestrial freshwater wetlands, N Present hybrid freshwater swamps, brackish and saline lakes, (Whiskered floodwaters, sewage farms, irrigated croplands and Tern) large dams. 1 Conservation Codes: CE: Critically Endangered. EN: Endangered. VU: Vulnerable. R: Rare. Mi: Migratory, Ma: Marine 2 Likelihood Codes: Unlikely: Project Area does not contain habitat and/or is outside of the species’ current known distribution and the species has not been recorded within the Project Area to date. Possible: Project Area contains preferred habitat that may support a population of the species, however the species has not been recorded within the Project Area to date Present: Project Area contains preferred habitat that may support a population of the species, and the species has been observed within the Project Area during ecological surveys
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Ardea alba and Ardea ibis (Great and Cattle Egrets) Habitat Summary
The Great Egret is partially migratory, with northern hemisphere birds moving south from areas with cold winters. The overall population trends of the Great Egret is not well understood (Maddock, 2000). This may be attributed in part to the difficulty associated with assessing trends for a species that occupies individual sites erratically, and often in highly variable numbers across a wide geographic area (Wetlands International, 2006). Populations across Australia fluctuate in size due to the highly variable availability of suitable wetland habitat.
Great Egrets prefer shallow water, particularly when flowing, but have been seen on a range of watered areas, including damp grasslands. The Great Egret has been reported in a wide range of wetland habitats (e.g. inland and coastal, freshwater and saline, permanent and ephemeral, open and vegetated, large and small, natural and artificial) (Kushlan and Hancock, 2005). Great Egrets can be seen alone or in small flocks, often with other egret species at night that roost in groups.
The Great Egret may retreat to permanent wetlands or coastal areas when other wetlands are dry (for example, during drought). This may occur annually in some regions with regular wet and dry seasons, or erratically where the availability of wetland habitat is also erratic i.e. the filling of Lake Torrens which is east of the corridor.
In north-eastern South Australia, it has been suggested that at least 12 breeding colonies exist. Non- breeding birds have been recorded across much of Australia, but avoid the driest regions of the western and central deserts (Marchant & Higgins, 1990; McKilligan, 2005).
Like many other egrets, the Cattle Egret nests in trees in colonies with other water birds. This species will typically remain within low-lying areas feeding on insects disturbed by grazing stock. They are common in northern Australia but are uncommon in most of their range in southern Australia. The Cattle Egret is found in grasslands, woodlands and wetlands, and prefers moist areas with tall grass, shallow open wetlands and the margins of wetlands. It also uses pastures and croplands, especially where drainage is poor. They are partially migratory, moving during winter. Whilst neither species has been recorded, it is possible that they occur at pastoral dams and inland wetlands within the Project Area, flying over or using areas within the corridor as stopovers on the way to other wetland areas within the region.
Nature and Extent of Likely Impact
The potential impacts associated with this species are considered similar to those of Listed Migratory Shorebirds and Waders (see previous sections).
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Merops ornatus (Rainbow Bee-eater) Habitat Summary
The Rainbow Bee-eater is distributed across much of mainland Australia. It is a marine-listed species under the EPBC Act, and has previously been recorded in the Project Area.
The number of locations that the Rainbow Bee-eater occurs in is unknown, and has not been estimated. It is assumed that the species is widespread given its ability to undertake long-distance movements (Barrett et al, 2003) however it is difficult to predict localised populations. The Rainbow Bee-eater occurs in open woodlands and shrublands, including Mallee, and in open forests that are usually dominated by Eucalypts. It also occurs in grasslands (Gibson, 1986) and, especially in arid or semi-arid areas, in riparian, floodplain or wetland vegetation assemblages (Badman, 1989). Its ability to undertake long-distance movements makes this species highly mobile.
Nature and Extent of Likely Impact
The potential impacts associated with this species are considered not significant due to the wide distribution and transient nature of the species distribution, and the lack of predicted impact to the preferred Mulga creekline habitat associated with the Project.
Larus novaehollandiae (Silver Gull) Habitat Summary
As reported in Birdlife Australia (http://birdlife.org.au/bird-profile/Silver-Gull, visited 2013), the Silver Gull has a white head, tail and underparts Silver Gull has a white head, tail and underparts, with a light grey back and black-tipped wings. In adult birds the bill, legs and eye-ring are bright orange-red. The Silver Gull is common throughout Australia and is also found in New Zealand and New Caledonia. The Silver Gull is found at virtually any watered habitat and is rarely seen far from land. Silver Gulls nest in large colonies on offshore islands, and will often raise two broods in a year, with both adults share nest- building, incubation and feeding duties. Eggs are laid in a shallow nest scrape, lined with vegetation. As with many other gull species, the Silver Gull has become a successful scavenger, readily pestering humans for handouts of scraps, pilfering from unattended food containers or searching for human refuse at tips. Other food includes worms, fish, insects and crustaceans. With this increased availability of food in the form of refuse, the population of Silver Gulls has exploded, and offshore islands which once supported small breeding colonies are now over-run. With so many gulls dominating these breeding islands, it is becoming increasingly difficult for terns and other seabirds to breed there.
Nature and Extent of Likely Impact
The potential impacts associated with this species are considered not significant due to the wide distribution and significant populations of the species, noting that Silver Gulls have not been recorded within the Project Area to date.
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Charadrius ruficapillus (Red-capped Plover) Habitat Summary
The Red-capped Plover is a small shorebird with a white front, rufous neck and light brown wings. Unlike other shorebird species in this referral, the Red-capped Plover does not migrate internationally. The species inhabits the entire Australian coastline where suitable habitat is present, and can be found inland, especially at salt lakes (Simpson 1993; Pizzey and Knight 2007). The species inhabits sandy beaches, mudflats, saltmarsh, fresh and saline wetlands, and dams. In each of these habitats, they forage above and along the water line for invertebrates located on and within the substrate (Abensperg-Traun and Dickman 1989).
Within the Project Area, the Red-capped Plover were observed on five occasions at dams distributed over the Project Area.
Extent and Nature of Likely Impact
The Red-capped Plover has a very similar ecology to migratory shorebirds, and therefore refer to the extent and nature of likely impact for migratory shorebirds discussed earlier in this section.
Cacomantis pallidus (Pallid Cuckoo) Habitat Summary
The Pallid Cuckoo is a medium sized passerine (28 – 33 cm). They are distributed over the entire Australian continent and occur in a suite of habitats, which include: woodlands, scrublands, mangroves, farm and pastoral land (Pizzey and Knight, 2007). The Pallid Cuckoo will utilise low perches as a vantage point to spot prey on the ground below, as well as forage within the canopy of trees. The Pallid Cuckoo is a nest parasite, laying its egg within the nests of a variety of small passerine species, including honeyeaters, woodswallows and Willie Wagtails (Rhipidura leucophrys) (Landstrom et al. 2010). The Pallid Cuckoo is migratory across the southern extent of its range, where it will spend the spring and summer months, and will spend the cooler winter months inland (Pizzey and Knight 2007).
Extent and Nature of Likely Impact
The Australian wide distributed of the Pallid Cuckoo, matched with its ability to inhabit a wide variety of habitats means that the proposed vegetation clearance in the Project Area will have no impact on the species population size or viability.
Chalcites basalis (Horsfield’s Bronze-Cuckoo) Habitat Summary
The Horsfield’s Bronze Cuckoo is a small passerine (15-17 cm). They are distributed over the entire Australian continent, and are therefore present within a wide range of habitats, which include: woodlands, Mallee, mulga, saltbush, saltmarsh and mangroves (Pizzey and Knight 2007). The species is a nest parasite, and therefore uses fairywrens, thornbills, robins, and other small passerines to incubate their eggs and brood their young (Brooker and Brooker 1989). The Horsfield’s Bronze Cuckoo is
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migratory across the southern extent of its range, where it will breed during the summer months. Inland, such as within the Project Area, it may spend the cooler months and breed (Pizzey and Knight 2007).
Extent and Nature of Likely Impact
The Australian wide distributed of the Horsfield’s Bronze Cuckoo, matched with its ability to inhabit a wide variety of habitats means that the proposed vegetation clearance in the Project Area will have no impact on the species population size or viability.
Chalcites osculans (Black-eared Cuckoo) Habitat Summary
The Black-eared Cuckoo is a species of small passerine (19 – 20 cm) (Simpson 1993). The Black-eared Cuckoo is distributed over the Australian continent, and is only vacant from the wet east coast, Tasmania and Nullabor IBRA region (Pizzey and Knight 2007). The species inhabits drier woodlands, scrublands, mallee, mulga, lignum, saltbush, and riverside thickets. (Pizzey and Knight 2007). Like other species of cuckoo, the Black-eared Cuckoo is a nest parasite and part migratory, with part of the population migrating to the south coast to breed in spring (Pizzey and Knight 2007).
Extent and Nature of Likely Impact
The near Australian wide distributed of the Black-eared Cuckoo, matched with its ability to inhabit a wide variety of habitats means that the proposed vegetation clearance in the Project Area will have no impact on the species population size or viability.
Chlidonias hybrid (Whiskered Tern) Habitat Summary
The Whiskered Tern is a small species of tern that migrates between northern Australia; where it spends the non-breeding seasons, and southern Australia; where it breeds from September to March (Pizzey and Knight 2007). They are able to inhabit both coastal and inland environments, where irrigated land, wetlands; both brackish and saline, salt works and sewage ponds are present (Pizzey and Knight 2007). The species feeds on both terrestrial and aquatic invertebrates as well as fish (Dostine and Morton 1989).
Nature and Extent of Likely Impact
The Whiskered Tern will not be impacted by vegetation clearance, however may be impacted by the development of the evaporation ponds, the TSF and the Decant Dam. The impacts will be as described for the migratory shorebird species (see previous section).
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3.1.6 Commonwealth Marine Area
There are no Commonwealth Marine Areas identified in the MNES Search area.
3.1.7 Commonwealth Land
One area of Commonwealth Land was identified in the MNES search area associated with the Australian National Railways Commission. The area of Commonwealth Land is overlapped by the buffer of the Protected Matters Search Area, and is not within the Project Area.
3.1.8 The Great Barrier Reef Marine Park
The proposed action is located in South Australia. Significant impacts will not occur on the Great Barrier Reef Marine Park.
3.1.9 A water resource, in relation to coal seam gas development and large coal mining development
The proposed action does not involve coal seam gas development or coal mining.
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3.2 Nuclear actions, actions taken by the Commonwealth (or Commonwealth agency), actions taken in a Commonwealth marine area, actions taken on Commonwealth land, or actions taken in the Great Barrier Reef Marine Park
3.2.1 Is the proposed action a nuclear action?
All nuclear actions, as detailed in Section 22 of the Act, should be referred to the Department of the Environment and Energy for a decision on whether assessment is required.
The definition of a nuclear action under the EPBC Act includes “establishing a large scale disposal facility for radioactive waste”. For non-uranium mines with elevated concentrations of naturally occurring radioactive materials, it is possible that this criteria is triggered for higher volume waste systems such as tailings storages facilities (TSFs).
While a TSF for a copper mining and processing operation would not normally be considered a “nuclear action”, the TSF for the operation will receive tailings that contain elevated concentrations of naturally- occurring radioactive material. Note that OZ Minerals will not be producing a uranium product.
It should be noted that TSFs for mines in Australia are subject to strict design controls to ensure long- term stability and containment of the tailings. See Section 5 of this document for further details on the design and operational controls applied to the Project’s TSF.
Under Regulation 2.02 of the EPBC Regulations, a proposed action meets the definition of a nuclear installation if the unsealed source activity value is greater than 106 Bq and the unsealed source activity concentration value is greater than 1 Bq/g.
As shown in Table 3.5, the activity concentration for the tailings is approximately 3.4 Bq/g. The average annual tailings production rate is approximately 5 Mtpa (5 x 1012 g). This equates to an activity value of approximately 1.5 x 1013 Bq for annual production – with an expected mine life of 27 years. Consequently, both the activity value and the activity concentration value in the EPBC Regulations will be exceeded and the proposed action therefore meets the EPBC Act definition of a nuclear action.
Table 3.5: Estimated Radionuclide Composition of Process Streams Material Uranium Series Radionuclide Unsealed source activity Concentration1 concentration value Mineralised ore2 Approx. 3 Bq/g 1 Bq/g
Copper Concentrate Approx. 1.3 Bq/g 1 Bq/g
Iron Calcium Precipitate3 Approx. 1 Bq/mL -
Tailings Approx. 3.4 Bq/g 1 Bq/g
Concentrate Treatment Plant Copper Approx. 0.15Bq/g 1 Bq/g Concentrate (export grade copper concentrate) Note 1: Concentration for U238 and all decay products assumed to be in secular equilibrium Note 2: Assumes an average uranium concentration of 239 ppm Note 3: Assumes 5% mass flow to concentrate and all radionuclides reporting to liquor which has a mass ratio of 2 parts liquor to 1 part solids.
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In recognising that the Project will exceed the threshold that defines ‘nuclear action’, OZ Minerals has undertaken a robust and detailed assessment to determine the potential radiological impacts to people and the environment from the TSF (as summarised in subsequent sections). The assessment shows that radiological impacts from the Project will be negligible.
While the proposed action triggers the “nuclear action” criteria, based on the assessment, it presents no radiological risks and the assessed radiological impacts of the TSF are negligible. As such, the level of assessment and control for the proposed action should be commensurate and therefore considered to be not a “controlled action”.
Nature and Extent of Likely Impact on the Whole Environment Radioactive materials occur naturally in soils, water and the air and are responsible for much of the naturally occurring radiation known as ‘background radiation’. Including cosmic radiation, naturally occurring background radiation is variable and causes radiation exposure to people everywhere.
When discussing impacts of radiation on people, it is usual to say that people are ‘exposed’ to radiation resulting in a ‘dose’. The term ‘dose’ is a standardised measure of radiation impact, reported as ‘Sieverts’ (Sv), which takes into account the different types of radiation and the way that the particular exposure occurs.
The effects of radiation depend upon the size of the dose received. At doses above 1,000 mSv, a range of radiation effects are immediately observable in individuals. At doses between 100 and 1,000 mSv, effects are observable in populations or groups of people, and there is a probability that the dose may result in an impact to an individual. Below a dose of 100 mSv, it is difficult to observe any effects in populations, however, it is assumed that the probability of an effect still exists.
Naturally occurring background radiation produces doses ranging from 1 to 10 mSv/y in different parts of the world. In Australia, the average dose from background radiation is 2.3 mSv/y (ARPANSA, 2012).
For the management of radiation, the IAEA notes that controls should be commensurate with the risk and suggests that this be reflected in the level of regulation. Recent international guidance from the IAEA (GSR3) formally develops and encourages this approach for naturally occurring radioactive materials, noting that if doses are less than 1 mSv/y from a practice where naturally occurring radioactive materials are involved, the practice could be considered as being exempt from regulation (see Schedule 1 of GSR3).
Radionuclide Composition of Project Materials The mineralised orebody commences at a depth of approximately 400 m below ground level, extending a further 700 m to 1,000 m deeper. Above the orebody, there is a non-mineralised cover sequence material (containing less than 5 ppm uranium). The mineralisation itself lies within a basement rock that is also non-mineralised, but with a higher natural uranium content of approximately 20 ppm. On average, the orebody contains approximately 239 ppm uranium. This is equivalent to approximately 3 Bq/g of U238 as head of the U238 decay chain. Since the mineralisation is relatively undisturbed, it is highly likely that the concentrations of the decay product radionuclides are identical.
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For reference, the world average uranium content of soils is 3 ppm, and the uranium grade at Olympic Dam is approximately 600 ppm. At uranium concentrations below 600 ppm, extraction is not generally considered economic. The radionuclide concentration for the process streams is shown in Table 3.5
Radiological Aspects OZ Minerals has conducted a radiological assessment of the Project and reports are as follows: Appendix 4 Environmental and Public Radiation Impact Assessment: Addressing impacts to the environment and members of the public. Appendix 5 Occupational Radiation Assessment: Addressing impacts to workers at the proposed action.
Public Exposure
Based on a number of conservative assumptions (detailed in Appendix 4), radiation exposure to members of the public will be a fraction of the regulatory limit of 1 mSv/y.
In this assessment, the locations of interest have been selected conservatively and are: Closest Project eastern boundary of the proposed Mining Lease (approximately 5 km to the east of the main processing plant area) Closest Project western boundary of the proposed Mining Lease (approximately 10 km to the west of the main processing plant area) South Eliza Dam (approximately 10 km south of the main processing plant area and approximately 2 km south of the southern-most edge of the proposed TSF) Accommodation camp (approximately 5 km to the south-south-west of the main processing plant area).
Choosing these locations represents a worst-case exposure scenario, as the nearest homestead is over 15 km south of the TSF. For the accommodation camp, the dose assessment treats camp workers, such as cleaners and chefs, as members of the public and applies a dose limit of 1 mSv/y.
The assessment is based on the scenario where a member of the public resides at the locations of interest for 24 hours per day, 365 days per year for the three boundary locations. For workers at the accommodation village, it applies a residence time of 4,000 hours per year in line with expected working hours.
The potential exposure pathways for members of the public are: Irradiation by gamma radiation Inhalation of the decay products of radon Inhalation of radionuclides in dust Ingestion of animals or plants that have been exposed to emissions.
Gamma radiation exposure to members of the public from sources within the Project Area is considered negligible due to the distance between the sources and the public. The sources of gamma radiation (for example, ore stockpiles) are well within the Project boundary and inaccessible by the public.
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Doses to members of the public from the inhalation of radon decay products and radionuclides in dust have been calculated as shown in Table 3.6. Note that the ICRP has recently recommended an increase in the dose conversion factor for radon decay products (ICRP 2015), although this has yet to be adopted in Australia. The increase is a factor of 2.4 and the doses using the new dose conversion are shown here.
These doses are well below the regulatory limit for members of the public of 1 mSv/y.
The ingestion doses have been calculated for people living at each of the locations based on the conservative assumption that all food consumed is sourced from the location. In practice, the Carrapateena region is sparsely populated with plants and animals due to the lack of surface water. Therefore, consuming food solely generated in the region is highly unlikely.
The assessment method assumes that dust emissions from the operation deposit in the surrounding environment are taken up by plants and animals. Exposure to people occurs when the plants and animals are consumed. The assessment only considers the Project-originated radionuclides.
The total dose estimates at the sensitive receptors can be seen in Table 3.6.
Note that the doses are based on 100% occupancy (that is 8,760 hours per year) at these locations (apart from the accommodation village). The worst-case dose is estimated to be 0.041 mSv/y, which is more than an order of magnitude less than the regulatory limit for members of the public of 1 mSv/y.
Table 3.6: Public Total Dose Estimates
Exposure Pathway Dose (mSv/y) Location Dust RnDP Total Regulatory Limit Gamma Ingestion Inhalation Inhalation Dose Closest eastern 0.000 0.004 0.022 0.015 0.041 boundary of ML 1 mSv/y Closest western 0.000 0.004 0.006 0.001 0.011 boundary of ML (All locations below regulatory limit) South Eliza Dam 0.000 0.004 0.022 0.009 0.033
Accommodation 0.000 0.002 0.013 0.009 0.024 camp * Note that the ICRP has recently recommended an increase in the dose conversion factor for radon decay products (ICRP 2015), although this has yet to be adopted in Australia. The increase is a factor of 2.4 and the doses using the new dose conversion factor has been shown here.
Based on a number of conservative assumptions, radiation exposure to members of the public will be a fraction of the regulatory limit of 1 mSv/y. Consequently, the radiological aspects of the proposed action will not significantly impact members of the public.
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Flora and Fauna Exposure Appendix 4 outlines the potential radiological effects of the operation on non-human biota (NHB). The assessment has been conducted based on the potential airborne emissions that lead to the deposition of radioactive dusts on surrounding soils. It can be concluded from the ERICA (Environmental Risk from Ionising Contaminants: Assessment and Management) assessment that there is no radiological risk to reference plants and animals, including kangaroos, from emissions from the proposed Project.
Post-Closure OZ Minerals intends to ensure that the Project is closed and rehabilitated to an approved standard with a focus on safety and structural stability. The standards would be sufficient to ensure that radiological impacts are negligible.
To emphasise this, OZ Minerals has indicated that the radiological closure goals for the Project are to ensure that radiation levels are such that they are consistent with pre-operational levels. Therefore, it is expected that there will be no long-term radiological impacts of the Project following closure.
During rehabilitation, surface infrastructure would be removed and recycled or disposed of in accordance with the appropriate requirements. The mine openings would be sealed to prevent emissions and the SLC subsidence zone would be made safe and secure. The TSF structure would remain in perpetuity.
Post-closure air quality modelling has shown that concentrations of radon and dusts (containing radionuclides) are minor in level and limited in extent. At the edge of the TSF surface footprint, the radon emissions are estimated to conservatively add approximately 10% to the average naturally occurring radon concentrations because of the relatively low radon emissions rate from the tailings material, and the natural atmospheric dispersion that occurs. At greater distances from the closed TSF, the radon concentrations reduce substantially and would be difficult to differentiate from background variability within a few hundred metres.
Dust emissions post-closure are expected to be slightly elevated near the TSF, but would become indistinguishable from background variation within one or two kilometres, with dust deposition decreasing to background within a few hundred metres.
In addition to considering post-closure radiation concentrations, a radiological risk assessment was conducted as part of the preliminary design work on the TSF. This was used to identify potential future radiological exposure situations and make a qualitative assessment on the potential doses from those scenarios. No scenarios were identified where doses were of concern.
Occupational Exposure Occupational exposure is addressed in Appendix 5 Occupational Radiation Assessment. This concludes that the impacts would be manageable, with potential doses well below the recognised limits. A summary of the radiological impacts of the proposed Project is outlined in Table 3.7.
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Table 3.7: Summary of Radiation Impacts during the Proposed Project
Expected Dose/Impact Dose Limit/Standard Dose Groups (mSv/y) (mSv/y) Workers <6 20
3.2.2 Is the proposed action to be taken by the Commonwealth or a Commonwealth agency?
The proposed action is not to be taken by the Commonwealth or a Commonwealth agency.
3.2.3 Is the proposed action to be taken in a Commonwealth marine area?
The proposed action is not in a Commonwealth marine area.
3.2.4 Is the proposed action to be taken on Commonwealth land?
The proposed action is not on Commonwealth land.
3.2.5 Is the proposed action to be taken in the Great Barrier Reef Marine Park?
The proposed action is not in the Great Barrier Reef Marine Park.
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3.3 Other Important Features of the Environment
3.3.1 Flora and Fauna
Vegetation Structure and Associations The Study Area is located on stony hills and plains-dominated formations that cover over 90% of the area. This is accentuated by ephemeral drainage lines that fall away to saline creeks and depressions (see Appendix 2 Ecological Baseline Assessment).
Tableland soils are typically heavy self-mulching clays that are highly sodic and dispersive. Without the flat stones that act as the mulch in place, the soil may be subject to high levels of erosion. Vegetation cover on these areas is typically below 1 m in height and highly homogenous. Species commonly recorded in this area come from genera such as Frankenia (Sea Heath), Atriplex (Saltbush) and Tecticornia (Samphire). These are the dominant structure present in the wider area and the general landscape is devoid of substantial tree or shrub cover.
The ephemeral drainage lines are typically dominated by small shrubs and trees that persist through higher water flows and flushing of the soil profile. These often have a higher diversity of flora species than the surrounding stony hills. Major drainage lines support a wider range of species and larger trees, particularly Eucalyptus camaldulensis (River Red Gum). These are believed to persist through sourcing water from the soil profile, recharged by rainfall and surface water runoff, as well as from the accumulation of infiltrated surface water at the base of the alluvium sediments on low permeability residual clay / rocks. This results in zones of high habitat potential in an otherwise sparse environment. These trees provide hollows and other habitat resources for fauna species. The lowest lying creeks with highly saline branches and flood out zones are dominated by Tecticornia and other halophytes (salt tolerant plants) commonly recorded in arid regions.
Soil and vegetation characteristics are further described in Section 3.3.4.
A field survey of the proposed Western Infrastructure Corridor was undertaken in 2016, identifying a further two dominant vegetation associations and two sub-dominant vegetation associations to those observed within the Study Area.
Vegetation associations present within the Study Area and disturbance calculations are summarised in Table 3.8 and illustrated in Figure 3.2. Estimated land disturbance area for all Project development is 2,924 ha as summarised in Table 2.22 and shown in Figure 3.2.
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Table 3.8: Project Area Vegetation Associations
Percent Representation Area Vegetation Reduction Description in the Project Cleared Association in Ecology Area (ha) (ha) Study Area Chenopod shrubland Atriplex vesicaria (Bladder Salt Bush) +/- Tecticornia medullosa (Samphire) 1 3,4526 1716 4.97% Low Open Shrubland found on the open hills and plains landforms. Western Myall Woodland Acacia papyrocarpa Very Low Woodland over Atriplex vesicaria (Bladder Salt Bush) +/- Ptilotus obovatus (Silver 2 Mulla Mulla), Dodonaea lobulata (Lobe Leafed 812 0 0 Hop Bush), Acacia tetragonophylla (Dead Finish) and Eremophila spp. (Emu Bush), primarily recorded in ephemeral drainage. River Red Gum Eucalyptus camaldulensis var. Open Woodland over Sida petrophila (Rock Sida), Dodonaea lobulata (Lobe-leafed Hop-bush), 3 Maireana spp. (Bluebush), Rhagodia spinescens 4,272 226 5.29% (Spiny Saltbush) and emergent shrub species recorded in major drainage channels with boulder, stone and gravel bases. Samphire (Tecticornia medullosa) Low Open Shrubland on saline mudflats and marshes where 4 they may be temporarily inundated following 0 0 0 run-off events but do not flush, with the existing water evaporating off, increasing salinity. Boree (Melaleuca xerophila) Shrubland recorded 5 in saline major creek lines in proximity to Lake 0 0 0 Torrens. Swamp Cane-grass (Eragrostis australasica) Tussock/Hummock Grassland +/- emergent Melaleuca zerophylla (Boree) Shrubland, very 6 0 0 0 isolated occurrences on perched water retention areas on hills and is very sparsely present although widely distributed. Northern Cyprus Pine (Callitris glaucaphylla) +/- Mulga (Acacia aneura) Low Woodland with Sandhill Wattle Acacia ligulata (Umbrella Bush) 7 Shrubland / Dodonaea viscosa var. angustissima 12,355 133 1.08% (Narrow-leaf Hop Bush) Open Shrubland +/- Zygochloa paradoxa (Sandhill cane-grass) association recorded on sandy dunes and rises. Acacia aneura (Mulga) / Acacia papyrocarpa (Western Myall) open Woodland over Maireana 8 2,767 32 1.16% sedifolia / Maireana pyramidata / Maireana astrotricha / Atriplex vesicaria Shrubland. Tecticornia pergranulata (Black Seed Samphire) / 9 668 0 0 Nitraria billardierei (Nitre Bush) Low Shrubland.
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Flora Review of the Biological Database of South Australia (BDBSA) records from all surveys conducted in the Project Area indicate that a total of 462 flora species (consisting of 419 native species and 43 exotic species) have been recorded on or around the Study Area (including a 30 km buffer). Over the combined survey periods (2012 – 2016), 215 flora species represented by 37 families were observed in vegetation monitoring plots. Of these, 14 were exotic species. Species were largely represented by individuals from the Chenopodiaceae family with other dominant representation provided by Gramineae (Grass) species, Compositae (Daisies), Leguminosae (Peas, Wattles) and Malvaceae (Abutilon, Sida etc.).
Species diversity, species abundance, species cover and threatened species are summarised in Table 3.9 and discussed in detail in Appendix 2 Ecological Baseline Assessment.
Table 3.9: Flora Species Diversity, Abundance, Cover and Threatened Species
Subject Summary Species Species diversity was recorded at 16 100 m x 100 m quadrats from 2012 – 2016 in the Richness Carrapateena region. Flora species richness from 2012 – 2016 shows significant changes between survey periods. This is largely driven by the fluctuation in short term seasonal conditions. Annual species vary considerably with presence and absence of some species changing from one survey period to the next. Species Species abundance was recorded across 16 transects from 2012 to 2016 in the Carrapateena Abundance region. Mean long lived perennial species abundance over the survey period show very consistent values with a mean abundance of around 300 individuals per plot. This equates to a mean individual shrub value of 7,500 per hectare. There has been no significant survey-to-survey change in this value since the start of the survey period. Species Species cover was recorded across ten 1 m2 quadrats from 2012 to spring 2015 in the Cover Carrapateena region. The average total coverage over time closely follow the trends in richness which suggests that, as expected, higher cover values are driven by the presence of annual species. Over time, a consistent cover of perennial species would be expected, although many arid region flora species have adapted to defoliate during dry periods as a means of persisting. Threatened There are ten vegetation species of state or national conservation significance that could Species potentially occur within the Study Area. Nationally-listed flora species were discussed in Section 3.1.4, with state conservation significant species described in Table 3.10. More detail regarding the identified threatened species is presented in Appendix 2 Ecological Baseline Assessment. Plants and In general, the semi-arid zone supports few pest flora species. Dispersal mechanisms for these Pest species include rainfall events and fauna transportation (native, introduced and stock), however, Weeds these species are also easily distributed by vehicle movements along access tracks and by earthwork construction. Arid area weed species are also typically annual species that respond to heavy rainfall events and are widespread throughout the arid region. Since 2012, 23 exotic flora species have been recorded during monitoring surveys (including opportunistic sightings outside of transect areas). A number of species such as Common Sow thistle (Sonchus oleraceus), Bathurst burr (Xanthium spinosum), Saffron Thistle (Carthamus lanatus) and Smooth Mustard (Sisymbrium erysimoides) are considered naturalised across their range, are well established in the rangelands of South Australia. None of these species are listed as declared species under the Natural Resources Management Act 2004 (SA), with the exception of Bathurst Burr (Xanthium spinosum). Pernatty Station falls within the Gawler Ranges sub- region, however it is worth noting that the Kingoonya sub-region is exposed to same risks as those encountered at Pernatty. No exotic species are listed on the South Australian Arid Lands
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Subject Summary Natural Resources Management (SAALNRM) Kingoonya or Gawler ranges sub-region species target list. An additional two exotic pest plant species were observed during field surveys of the proposed IC, being Wards Weed (Carrichtera annua) and the state-declared species Patterson’s Curse (Echium plantagineum). Under the Natural Resources Management Act 2004 (SA), landowners have the legal responsibility to control declared plants. The Government of South Australia has established a Declared Plant Policy for Bathurst Burr and Patterson’s Curse that detail the feasibility of containment and control costs associated with its management. Bathurst Burr and Patterson’s Curse are highly visible when growing, and control in pasture is readily achieved by commonly used selective herbicides, or spot spraying of small infestations with non-selective herbicides.
Table 3.10: Carrapateena State Conservation Significant Flora Species
Species Name Conservation Status Likelihood and Common National State within Leases Habitat Name (EPBC) (NPW) from Surveys Frankenia EN V Possible The species is a low, mat-forming perennial pilcata shrub on lower slopes of hills and in small (Sea-heath) run-off channels. Most confirmed records of this species are from the Breakaways, approximately 30 km north of Coober Pedy in South Australia. Sclerolaena R Present At present, this is an undescribed species. The ‘Pernatty known distribution is restricted to an area of Station’ approximately 25 hectares and consists of approximately 1,000 individuals that appear to be a true perennial lifeform, living for more than three years. It is currently persisting in a stony tableland habitat type that makes up the large majority of the available habitat. Gilesia R Present Typically found on saline clay habitat and its biniflora distribution is the central regions of Australia, (Western Tar- in the interiors of New South Wales, Western vine) Australia, South Australia and Northern Territory. Santalum V Present Sandalwood grows in loam soils and amongst spicatum rocks in woodland and scrubland areas, and is (Sandalwood) primarily found in the southern half of Western Australian and South Australia. Often occurs sporadically as individuals in a variety of habitats throughout the semi-arid rangelands of SA. Ranunculus V1 Present Known to occur in semi-arid rangelands in the sessiliflorus Flinders Ranges. var. pilulifer (Annual Buttercup)
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Species Name Conservation Status Likelihood and Common National State within Leases Habitat Name (EPBC) (NPW) from Surveys Atriplex V Possible Occurs on gibber slopes with other chenopod kochiana shrubs. It is known to occur in northern (Koch’s regions of South Australia, around Saltbush) Andamooka and north of Olympic Dam. Citrus glauca V Possible Known to occur within the semi-arid lands of (Desert Lime) South Australia usually on heavy clay soils. Gratwickia R Possible Little information is available on the habitat of monochaeta this species; however it has been located within the Gawler IBRA bioregion and is known to occur within Acacia woodlands and inland salt lakes and lagoons. Ophioglossum R Possible The species is known to inhabit moist places polyphyllum on sand hills and sandplains and can often (Large form large colonies on open clay loams. It is Adder’s- frequently encountered in ranges where it tongue) occurs in shallow soil pockets subject to flooding or amongst rocks or along stream banks. Orobanche R Unlikely The species is most abundant on sandy soils cernua var. and especially along drainage lines. Australiana (Australian Broomrape) 1 Also listed as threatened within the Arid Lands NRM region (DEH 2007). Conservation Status: National: Australia (Environment Protection and Biodiversity Conservation Act 1999), State: South Australia (National Parks and Wildlife Act 1972), EN: Endangered, V: Vulnerable, R: Rare Likelihood Codes: Unlikely: Project Area does not contain associations and/or is outside of the species’ current known distribution and the species has not been recorded within the Project Area to date. Possible: Project Area contains preferred habitat that may support a population of the species, however the species has not been recorded within the Project Area to date Present: Project Area contains associations that may support a population of the species, and the species has been observed within the Project Area during ecological surveys
Fauna The arid lands, such as the Arcoona tableland system predominantly support Chenopod shrublands, a vegetation community that are typically known to support relatively low mammal and reptile species diversity and richness when compared with other habitats due to the simplicity and uniformity of the habitat structure (i.e. generally no mid-storey or overstorey vegetation layer).
An intensive baseline survey was first undertaken in the Carrapateena region in 2007, over a large extent defined as the Regional Study Area. Bi-annual terrestrial flora and fauna field surveys have been undertaken within this Regional Study Area since 2012 to extend this baseline knowledge, and occur every autumn and spring to capture seasonal variation. Techniques used were based on guidelines for vertebrate surveys as defined by Owens (2000), which included a sequence of Pitfall, Elliott and Funnel traps installed at each trapping location.
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Results of surveys undertaken within the Study Area to date (2012 – 2016) show that up to 16 ground- dwelling mammalian species are commonly encountered, including five exotic species, with 33 species of reptile and five species of bat also being identified across the survey periods.
Bird species richness is also quite high for this type of landscape, with 112 species being encountered across the Project Area since 2012. Many of these are long-term residents, with 26 species being considered sedentary and resident species that occupy well-defined home ranges throughout the Project Area. The site is also frequented by migratory and transient species, with many of these species frequenting the site during periods that would be classified as preferential, generally after rainfall events.
A desktop survey and site visit of the Western Infrastructure Corridor linking the proposed mining and associated tenements to the Stuart Highway (the WIC) was undertaken in 2016, followed by a brief field survey. The conservation-significant species identified as potentially occurring within the IC were largely the same as those associated with the proposed Mining Lease, with the exception of the addition of the state rare Elegant Parrot (Neophema elegans) and the Commonwealth critically endangered Curlew Sandpiper (Calidris ferruginea).
Species diversity, species richness and threatened species are summarised in Table 3.11 and discussed in detail in Appendix 2 Ecological Baseline Assessment.
Table 3.11: Species Diversity, Abundance, and Threatened and Pest Species
Subject Summary Species Species diversity was recorded via trapping and opportunistic observations from 2012 to Diversity 2016 in the Carrapateena region for each of mammals, reptiles and birds. Species Species richness was recorded via trapping and opportunistic observations from 2012 to Richness 2016 in the Carrapateena region for each of mammals, reptiles and birds. Threatened Nationally-listed threatened and migratory species were described in Section 3.1.4. A further and Migratory nine State-listed threatened species have also been recorded as potentially occurring within Species the Project Area as described in Table 3.12. Conservation On rare occasions when Lake Torrens is inundated, it becomes a productive ecological Areas system, supporting breeding terrestrial species and migratory birds. Lake Torrens is listed in the Directory of Important Wetlands in Australia (DOEE, 2016). The ecological role stated in the directory is “When in flood, the lakes provide suitable habitat for large wader populations. Lake Torrens is one of the few arid zone areas where large colonies of Banded Stilts Cladorhynchus leucocephalus breed”. Birdlife International has identified Lake Torrens as an Important Bird Area (IBA) on the basis of it being a breeding ground for the vulnerable Banded Stilts species when the lake is inundated. Management considerations under the IBA (BirdLife Australia 2016) include the control of Silver Gull predation of nesting Banded Stilts The evaluation of the potential impacts of minerals and/or geothermal energy extraction or exploration. Pest and Feral A number of exotic species have been observed across the Project Area during the surveys. Animals Goats (Capra hircus), sheep (Ovis aries), Europpean Rabbits (Oryctolagus cuniculus), House Mouse (Mus musculus), Cats (Felis catus) and Red Foxes (Vulpes vulpes) are all recorded within the Project Area. All of these species are widespread throughout Australia and are commonly observed throughout much of the arid lands of South Australia. Areas of permanent water, availability of alternative food resources such as around human centres and unauthorized feeding may indirectly facilitate the increase in abundance of pest species.
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Subject Summary Pest animals potentially arrive through transport vectors and pests already present such as cats and foxes are aided by the presence of exotic birds and mice. Pest and feral fauna recorded in the Project Area in the period 2012 – 2016 are detailed in Appendix 2 Ecological Baseline Assessment. Abundance and diversity of pest species has remained relatively constant since the commencement of monitoring, with fluctuations correlated to meteorological conditions, and in particular rainfall. Sightings of rabbits, cats and foxes have been sporadic and low in numbers. Cats and foxes have been observed around the existing Advanced Exploration Works Accommodation Village, indicating that this may be providing a reliable food source for exotic carnivores. Prolific numbers have not been observed during the surveys. House mice were first recorded at both control and monitoring sites in 2014, albeit in small numbers. This species has been observed prior to any site disturbances indicating that the records may not be a result of mining-related activities. Goats have been noted on a number of surveys in creek lines or using rocky drainage lines in the north-west of the proposed Lease. These were generally small populations, with only a few goats noted. There have been periods, however, where a number of large herds have been observed. These were noted in almost all rocky gullies, but were also noted moving across flat open ground, most likely in search of water at nearby dams and areas with high food availability. During other surveys, goats still may be present in other parts of the proposed Lease that were not opportunistically visited. Similarly, rabbits have shown a large variation in population over the course of the monitoring period. This species, as with the other feral species mentioned above, are common within the arid rangelands, and are probably reacting to climatic stimulus.
Table 3.12: Carrapateena State Conservation Significant Fauna Species
Species Conservation Status Likelihood within Name and State Leases from Habitat Common National Surveys Name (EPBC) (NPW) Known (ML - Pseudomys identified within the australis Project Area during (Plains V V As described in Section 3.1.4 2007 and 2012 Mouse surveys) (Plains Rat)) Possible (IC) Possible (ML and IC Pezoporus – has not been occidentalis observed within the V, Mi V As described in Section 3.1.4 (Night Project Area and Parrot) considered unlikely to occur) The elegant parrot is found in two disjunct regions, Neophema one across southwestern Australia from Moora in elegans the north to Merredin and Esperance in the east, R Possible (IC) (Elegant and in southeastern South Australia (including Parrot) Kangaroo Island) north to Marree, and east into western Victoria.
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Species Conservation Status Likelihood within Name and State Leases from Habitat Common National Surveys Name (EPBC) (NPW) Found in a variety of landscapes and vegetation types in many parts of the world. Wide spread in Australia but tends to be rare and not commonly found in any region around Falco Known (ML - the continent. Cities have become an peregrinus identified within the important habitat for these birds, with R (Peregrine Project Area) skyscrapers and transmission masts mimicking Falcon) Possible (IC) the cliff faces on which they often roost and nest. Old quarries and mines have artificial cliffs that Falcons have been observed using for roosting, hunting vantage points and as breeding platforms. Known (ML - Chooses habitat such as grasslands and grassy Neophema identified within the woodlands in coastal areas through to semi- chrysostoma V Project Area in 2013 arid zone. This also includes a variety of dense (Blue-winged and 2014 surveys) Mallee or chenopod shrublands, heathlands, Parrot) Possible (IC) thickets and dunes. Actitis Known (ML - hypoleucos Mi, Ma R identified within the As described in Section 0 (Common Project Area) Sandpiper) Amytornis Possible (ML and IC modestus - not observed V EN As described in Section 3.1.4 (Thick-billed within the Project Grasswren) Area) Possible (ML and IC Ardea ibis – not observed Ma R As described in Section 0 (Cattle Egret) within the Project Area) Nephrurus Utilises a range of sand dune habitats Known (ML and IC - deleani including red dunes, adjacent swales and rises identified within the (Pernatty R as well as the whitish dunes and flats which are Project Area during Knob-tailed often associated with salt lakes in that region. 2013 survey) Gecko) Occurs in arid and semi-arid regions of southern Western Australia, and southwestern South Australia. The species generally inhabits Acanthiza chenopod shrublands with no overstorey, iredalei Possible (ML and IC dominated by Samphires or Maireana spp. iredalei - not observed (Bluebush) and Atriplex spp. (Saltbush) R (Slender- within the Project associations. It occasionally occurs in Acacia billed Area) shrublands and mangroves adjacent to more Thornbill) preferred habitat. In inland areas, the chenopod shrublands occupied by the Slender-billed Thornbill (western) are often located in close proximity to salt lakes.
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Species Conservation Status Likelihood within Name and State Leases from Habitat Common National Surveys Name (EPBC) (NPW) Cladorhynch Possible (ML - not This wader species disperses of large distances us observed within the and is most likely to inhabit ocean beaches leucocephalu V Project Area but has after breeding. The species also inhabits salt s (Banded been observed lakes and can occur in large flocks in Stilt) overflying) temporarily flooded saltpans and lakes. Climacteris The species inhabits the semi-arid interior of affinis Possible (ML - not Australia in habitats consisting of Mulga, (White- R observed within the Mallee, Desert oak, Callitris (Native Pine) and browed Project Area) Spinifex with scattered trees, and tree-lined Treecreeper) watercourses. Freckled ducks prefer permanent freshwater Stictonetta swamps and creeks with heavy vegetated Known (ML - naevosa growth. During drier times, they move from V observed within the (Freckled ephemeral breeding swamps to more Project Area) Duck) permanent waters including lakes, reservoirs, farm dams and sewage ponds. Northiella This species is known to inhabit open country Possible (ML – not haematogast in lightly timbered grassland, mulga, mallee, R observed in the er she-oak, watercourses or paddock trees. Project Area) (Bluebonnet) The Australian Bustard is a species that is generally found in open dry plains, grasslands Ardeotis Known (ML - and in open woodland. This species is highly australis V observed within the nomadic. In southern Australia, bustards are (Australian Project Area) perceived as short-term, irregular visitors Bustard) whereas populations that are more permanent persist in northern and north-eastern regions. 1 Also listed as threatened within the Arid Lands NRM region (DEH 2007). Conservation Status: National: Australia (Environment Protection and Biodiversity Conservation Act 1999), State: South Australia (National Parks and Wildlife Act 1972), Mi: Migratory, Ma: Marine, EN: Endangered, V: Vulnerable, R: Rare Likelihood Codes: Unlikely: Project Area does not contain habitat and/or is outside of the species’ current known distribution and the species has not been recorded within the Project Area to date. Possible: Project Area contains preferred habitat that may support a population of the species, however the species has not been recorded within the Project Area to date Present: Project Area contains habitat that may support a population of the species, and the species has been observed within the Project Area during ecological surveys.
Nature and Extent of Likely Impact The Project will require the clearing of land for the establishment of Project infrastructure, with a footprint of approximately 3,000 ha, the majority of which will be rehabilitated at closure. Vegetation communities within the disturbance footprint and habitats are well represented within the wider region, and little area of the less common vegetation associations are proposed to be disturbed. Impacts on flora and fauna are not predicted to be significant as a result of the clearing of native vegetation and fauna habitat. As discussed in Sections 3.1 and 3.3.3, there are also no predicted significant impacts to flora and fauna as result of the proposed action and interaction with the existing groundwater, surface water and air quality environment.
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3.3.2 Hydrology and hydrogeology
The Project Area lies within the surface water catchment of Lake Torrens and Pernatty Lagoon. The drainage basin is estimated to be approximately 26,100 km2 in area. The Arcoona Plateau, on which the Project Area lies, has a dendritic drainage pattern of short channels radiating from the main tablelands, with wide, shallow drainage channels and in the upper parts of the tablelands, and incised creeks in the lower parts. The normal condition for watercourses that drain the Plateau is dry, with flow occurring for short periods only following significant rainfall events. Mean annual rainfall in the area is approximately 200 mm. This low average rainfall, with occasional intense rainfall events, and high evaporation rates results in the ephemeral nature and high salinities recorded for surface waters in the Project Area.
Surface Water Six different surface water catchments interact with Project activities. These have been summarised in Table 3.13 and shown in Figure 3.3, and include the following catchments: Salt Creek Catchment Yeltacowie Creek Catchment Elizabeth and Gum Creek Catchment Pernatty Lagoon Catchment, cumulative of Yeltacowie Creek and Elizabeth and Gum Creek Catchments Eliza Creek Catchment Lake Torrens Catchment, cumulative of Salt Creek, Eliza Creek and Tadpole Creek Catchments, and Unnamed Catchment 3.
Table 3.13: Surface Water Catchment and Project Elements
Catchment Disturbance Catchment Catchment Description Project Elements (ha) (ha) Reduced (%) Yeltacowie Yeltacowie Creek is the third creek 69,015 Electricity 117 0.17 Creek catchment within the Project Area. transmission line Yeltacowie Creek is an ephemeral Access road stream that begins in the hills located Common to the south of Eliza Creek and Salt services Creek and flows west before turning alignment south and meeting Pernatty Creek amongst sand dunes. Pernatty Creek Groundwater continues to flow south west through wells the Western Infrastructure Corridor MPL and terminates at Pernatty Lagoon. Upstream of the junction with Pernatty Creek, Yeltacowie Creek has a catchment area of 600 km2, 30% of the Pernatty Lagoon catchment. Elizabeth Elizabeth creek crosses the Western 57,735 Electricity 21 0.04 and Gum Infrastructure Corridor MPL within transmission line Creek the Elizabeth and Gum Creek Access road catchment area, and terminates at Common services the northern end of Pernatty alignment Lagoon (see Figure 3.3). Groundwater wells
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Catchment Disturbance Catchment Catchment Description Project Elements (ha) (ha) Reduced (%) Pernatty Pernatty Lagoon is an ephemeral 68,310 Electricity 73 0.11 Lagoon salt lake, fringed by sand dunes, transmission line located to the west of Lake Torrens. Access road The salt lake has a surface area of Common 209 km2 and a catchment of 1,730 services km2. The largest creeks terminating alignment at Pernatty Lagoon are Elizabeth Creek, which terminates at the Groundwater northern end of the lagoon, and wells Pernatty Creek and Yeltacowie Creek that terminate at the southern end of the lagoon. Unnamed Catchment contains unnamed 4,321 Electricity 12 0.27 Catchment ephemeral flow paths that terminate transmission line 6 within the catchment (i.e. no Site Access Road outflows from the catchment). Salt Creek Salt Creek is an ephemeral stream 19,834 Electricity 267 1.34 located to the west of Eliza Creek, transmission line and is the second of three creek Access road catchments within the proposed Common Mining Lease. Salt Creek also flows services in a northerly direction and alignment terminates at Lake Torrens. It has a catchment of 223 km2, constituting Groundwater 1.1% of the Lake Torrens catchment. wells Eliza Creek The largest ephemeral stream near 11,486 Mining Surface 1,268 11.04 the deposit is Eliza Creek, and one Infrastructure of three creek catchments within the Processing Plant proposed Mining Lease. Eliza Creek and Infrastructure flows in a northerly direction and Tailings Storage terminates at Lake Torrens, with a Facility 2 catchment of 115 km , constituting On-site power 0.56% of the Lake Torrens generation catchment. Water Supply Infrastructure Electricity transmission line Access road Common services alignment Groundwater wells Ancillary infrastructure Unnamed Catchment contains an unnamed 2,505 Mining Surface 1 0.04 Catchment north-east flowing creek line, Infrastructure 3 terminating in Lake Torrens. Tadpole Tadpole Creek is located in the 5,740 Water Supply 5 0.08 Creek eastern portion of the Project Area Infrastructure and flows in a northerly direction Access track and terminates in Lake Torrens.
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Catchment Disturbance Catchment Catchment Description Project Elements (ha) (ha) Reduced (%) Lake Lake Torrens, which lies to the north 2,690,000 As above 1,541 0.06 Torrens and east of the Project Area, is a Basin 240 km long dry salt flat, and has been recorded to fill with water once in the past 150 years (1989). The catchment predominantly drains from the norther Flinders Ranges, located to the east of Lake Torrens. Only a small percentage of rainfall runs off the catchment, and the surface water balance is dominated by rain landing directly on the lake surface.
Surface Water Modelling Overview Surface water modelling was undertaken to support the Mining Lease Proposal and to determine the magnitude of effects to the existing surface water environment as a result of surface water effecting activities. As shown in Table 3.13, each catchment is effected as a total by varying percentages. The percentage of the catchment that was effected determined the overall need to undertake a detailed Modelling and Assessment of Effects Study.
The majority of effect as shown in Figure 3.3 occurs to the Eliza Creek Catchment. This was identified as a key focus area, and as a result has been independently assessed. Due to the low percentage of disturbance across the other catchments, it was not necessary to model the quantities of water that may no longer enter the catchment, as the effects are considered negligible.
Reduction in surface water flows
Modelled predictions demonstrate that as a result of the proposed operations, surface water flows are estimated to be effected as follows: TSF will capture approximately 11% of Eliza Creek surface water flows. SLC subsidence crater will capture approximately 4% of the Eliza Creek catchment run-off. Total catchment size reduction estimated at 15% of the Eliza Creek run-off. Taking the ‘cease to flow’ threshold as 0.1 L/s, the average number of days with creek flow is expected to reduce from 6.7 days per year to 6.6 days per year. Prior to development, 39% of flow events are likely to be 1-day duration. Post development, 41% of flow events are likely to be 1-day duration. Total number of flow events per year will not change. Flood water depth would be reduced by approximately 10-20 cm, with greater reductions immediately downstream of the TSF dam wall embankment during storm events. A 15% reduction in the Eliza Creek catchment is equivalent to a reduction in the Lake Torrens catchment of 0.085%.
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The overall changes to surface water quantity within the Eliza Creek and Lake Torrens catchment described above are considered negligible.
Nature and Extent of Likely Impacts Reduction Surface Water Flows to Lake Torrens
The inflow to Lake Torrens is largely only effected by any alteration in volumes to Eliza Creek. A 15% reduction in the Eliza Creek catchment is equivalent to a reduction in the Lake Torrens catchment of 0.085%. These effects will emerge during construction and operation and will remain into perpetuity due to the TSF and subsidence zone remaining as final landforms. Reduced surface water flows representing 0.085% is considered to represent a negligible change to the overall Lake Torrens water budget and will not result in any significant impacts.
Changes to Surface Water Quality in Eliza Creek and Lake Torrens from Tailing Storage Facility Discharge
Tailings generated during processing operations would report to the Tailings Storage Facility (TSF) for permanent disposal that is located within the Eliza Creek and Lake Torrens surface water catchment. The TSF embankment and associated infrastructure has been identified as a Fundamental Design Control that prevents the discharge of tailings to surface water. No change to the baseline surface water quality as a result of tailings solids or liquor release to Eliza Creek or Lake Torrens is predicted to occur during operations and post closure and therefore no impacts are predicted.
Two main mechanisms prevent the release of tailings material to the downstream environment. These include the freeboard capacity and the embankment wall as outlined in Table 2.8.
The TSF design has been independently peer reviewed to confirm it is capable of managing the placement and containment of tailings in the short and long term.
The TSF surface has been demonstrated to have the capacity to collect sediments generated from the upstream Eliza Creek catchment, including from surface borrow pits established during TSF construction, over the long term without compromising the ability of the TSF surface to store a Probable Maximum Precipitation (PMP) storm event.
The TSF will prevent the release of tailings to the surface water environment and has been designed in accordance with ANCOLD Guidelines, with an independent peer review undertaken by an industry expert. There are no predicted significant impacts as a result of operation and closure of the TSF.
Change in Surface Water Quantity at Watercourse Springs within the Salt Creek Catchment
A number of groundwater-dependant watercourse springs have been identified as occurring in the Salt Creek Catchment. Due to the negligible reduction in the Salt Creek Catchment illustrated in Figure 3.3, modelling has not been undertaken and the watercourse springs of Salt Creek are considered to be unaffected by reduced surface water flows and therefore will not result in any significant impacts.
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Change in Surface Water Quantity at Water Holes within the Eliza Creek Catchment
The North Eliza Soak has been identified as occurring in the Eliza Creek Catchment. The Project footprint located in the Eliza Creek Catchment relates largely to the Processing Plant, TSF, and Subsidence Zone Crater and associated infrastructure and represents a 15% reduction in Eliza Creek Catchment. The number of creek flow events would remain unchanged The waterholes within the catchments are considered to have low baseline aquatic flora values due to the infrequent nature of run-off events within this system and will not lead to any significant impacts.
Change in Height of Flood Events along Eliza Creek reducing Surface Water Available for Terrestrial Ecology
Eliza Creek flows in a northerly direction from the Project Area, and terminates at Lake Torrens. Eliza Creek has a catchment of 115 km2, constituting 0.56% of the Lake Torrens catchment. Modelling indicates that 93.5% of rain events are expected to generate little to no runoff, with runoff from larger rain events reaching up to 13% of the daily rainfall. Estimated stream flow hydrographs for Eliza Creek at the outfall to Lake Torrens indicate that the creek tends to flow only several times a year for short durations (1-2 days).
The TSF catchment will be approximately 13 km2, which is 11% of Eliza Creek catchment. The Processing Plant area within the surface water management infrastructure represents approximately 0.25 km2 (approximately 0.2% of the Eliza Creek catchment) and the SLC subsidence zone and upstream catchment will be approximately 4.35 km2 (4% of Eliza Creek catchment). Of this catchment, runoff from approximately 1.6 km2 would be diverted around the SLC zone via cut drains, leaving 2.7 km2 catchment draining to the centre of the depression. There is an expected reduction of run-off events given the reduction in size of the total catchment. This will not be significant considering that run-off events occur so infrequently (run-off events of greater than 10 mm occur on average 20 times in every one hundred years). The relatively small reduction in catchment size would therefore not significantly impact the overall health of existing flora communities.
Change in Surface Water Quality due to the Generation of Suspended Solids
There is the potential for an increase in total suspended solids associated with water run-off from stockpiles and disturbed areas during construction, operations and closure. The stone cover that stabilises the soil profile in the study area, once removed, leaves the highly sodic unstable soils at risk of transportation across the landscape. Areas where construction occurs in close proximity to the minor creeklines and runoff lacks time to settle out prior to entering the creek system has the potential to smother vegetation, particularly small herbaceous species that are of lower prevalence in the makeup of vegetation communities. This may lead to a reduction in overall local diversity. The management of surface water runoff from disturbed areas, including the interception of sediment-laden waters at the source through surface water management infrastructure and sediment and erosion controls, ensures that the impacts to surrounding vegetation will not be significant during operations. Post-closure there should be little loss of topsoil following any closure works through providing contour ripping, soil crusts and re-establishment of landscape function through soil cover such as rocks and annual and perennial
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herbaceous growth. Infrequent run-off events are expected to result in no significant impacts to surrounding vegetation communities.
Changes Surface Water Quality from Chemical and Hydrocarbon Storage
Project activities will require the storage and handling of chemical and hydrocarbons during all phases of the development. Chemicals and hydrocarbons will be stored within appropriate containers relevant to the material being stored and bunding in accordance with EPA Guidelines that will prevent the release to surface water and will not result in any significant impacts.
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Groundwater
Summary The principal known aquifers are the Tent Hill Aquifer (THA), Whyalla Sandstone Aquifer (WSA), Pandurra Formation, and, to a lesser extent, the Woolacalla Dolomite and the Nuccaleena Formation. Aquitards include the Arcoona Quartzite, Woomera Shale, Whyalla Sandstone and the Tapley Hill Formation.
Figure 3.4 presents the baseline conceptual hydrogeological model for the Project based on data collected in the region. The conceptual model shows: Regional groundwater flow is predominantly from west to east toward Lake Torrens, where evaporative discharge occurs. Regional groundwater flow through aquifers such as the THA and WSA primarily occurs through fractures, and to a lesser extent, the aquifer matrix. Transfer of water between hydrostratigraphic units occurs by leakage and preferred (transmissive) pathways associated with secondary porosity (such as faults). Watercourse springs located near to the margin of Lake Torrens are supported by structurally controlled groundwater discharge. Playa lakes in the region are also likely to act as groundwater sinks for surface drainages.
Groundwater recharge over much of the Stuart Shelf area is very low due to low rainfall and high evaporation rates, and is likely to vary considerably across the region with some areas capable of accumulating rainfall runoff experiencing higher infiltration rates (such as sand dunes and where aquifers outcrop/subcrop). It is expected most of the groundwater recharge occurs following significant rainfall events. Groundwater modelling undertaken for the Ming Lease Proposal indicate that recharge rates are likely to be in the order of 0.1 mm/yr.
Groundwater discharge likely occurs to some of the salt (playa) lakes located within the Project Area. Lake Torrens is a large episodic saline playa lake (~6,000 km2) that acts as the dominant regional evaporative sink for both surface water and groundwater. Groundwater residence times within the Project Area likely range between 10,000 and 20,000 years.
Groundwater sampled during baseline studies indicate the general water quality is hypersaline water (i.e. brine) created through evaporative processes from Lake Torrens. As part of the groundwater sampling program, samples were analysed for radionuclides and gross alpha and beta activity, the results of which indicate that naturally occurring groundwater radionuclide concentrations are generally consistent across the region.
Groundwater Modelling Overview The numerical groundwater flow model developed for the MLP was constructed in 2012. It has subsequently undergone a number of revisions and refinement with input from additional groundwater investigations undertaken in the time since 2012.
The hydrogeological data and information that supports development of the conceptual and numerical models is significant. This includes data drawn from groundwater related observations made during
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drilling, testing and sampling of almost 50 groundwater investigation wells within the broader Carrapateena Study Area, in addition to comprehensive studies completed for BHP Billiton’s Olympic Dam Expansion Project and other publically available reference materials including geological map sheets and South Australian Government water-related databases. The baseline (steady state) model was calibrated using a statistical analysis of observed versus simulated values of hydraulic head.
The predictive simulations consisted of two phases, and included the following: The Life-of-Mine (LOM) phase, run for 30 years from the commencement of operations Recovery phase, run for 5,000 years after the cessation of operations.
The modelling has been undertaken to determine the effects of the following groundwater-effecting activities and for the purposes of presenting a worst case/cumulative effect assessment on Lake Torrens: Underground mining operations, including ventilation shafts, the access decline and the SLC subsidence zone crater and rubblised zone Seepage from the TSF Radial Wellfield Future Project Wellfield Reverse Osmosis Brine injection wells.
The worst case predicted changes to the groundwater environment are summarised as: Depressurisation occurs due to dewatering of the underground development (decline, vent raises and the SLC mine) and extraction of groundwater from the existing production wells of the Radial Wellfield and the conceptual Project Wellfield. Limited pressurisation occurs due to injection of RO reject water into the THA and seepage from the TSF. Depressurisation within the upper profile of the crystalline basement rocks occurs in association with depressurisation of the overlying WSA. Below this shallow influence on the basement, depressurisation of the basement rocks by more than 5 m is generally restricted to within a radial distance of approximately 400 to 600 m from the SLC. Depressurisation of the Tent Hill Aquifer results in a desaturated zone within a radial distance up to 600 m from the SLC. Depressurised by 20 m of hydraulic head or greater within a distance of 6 km from the SLC. Depressurisation of the Whyalla Sandstone Aquifer results in a desaturated zone within a radial distance up to 400 m from the SLC. Depressurised by 20 m of hydraulic head or greater within a distance of 20 km from the SLC. At completion of mining, the dewatered underground workings are deactivated, allowing groundwater pressure near the mining area to begin to recover. All production wells are also switched off at the end of mining. Leakage of water from the TSF to groundwater is assumed to continue perpetually after mining at a rate of 0.4 mm/y. After three years post-mining, the SLC workings are 20 to 30 percent refilled. At approximately 9 to 10 years post-mining (2054 to 2055) the water table within the rubblised zone reaches the base of the subsidence crater and a lake commences to form within the crater.
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Nature and Extent of Likely Impact Change in Groundwater Quantity Lake Torrens
The worst-case cumulative scenario modelled predicts a decrease in the rate of discharge of groundwater from the bed of Lake Torrens by approximately 24% over LOM within the modelled extent of Lake Torrens (limited to a portion of the western edge likely to be affected by the Project). This is equivalent to the discharge within this extent decreasing from approximately 2.1 GL/y pre-mining to approximately 1.6 GL/y at year 30 LOM. As a proportion of the entire Lake Torrens water budget, this represents a 0.7% reduction and a 0.01 m reduction in the water table depth beneath the lake. Lake Torrens is, therefore, considered to be relatively unaffected by the proposed operations and no significant impacts are predicted.
Change in Groundwater Quality at Lake Torrens
Prior to the commencement of mining at Carrapateena, the Lake Torrens salt budget is estimated to grow by 2.8 Mt/y on average. If the evaporative loss of water from the subsidence-crater lake were assumed to be captured entirely from flow to the Carrapateena Arm of Lake Torrens, then 0.036 Mt/y would be removed from the Lake Torrens salt budget suggesting approximately 1% less salt loading to the lake groundwater system in the long-term. Lake Torrens is therefore considered to be relatively unaffected by the proposed operations and no significant impacts are predicted.
Change in Groundwater Quantity at Waterholes
A number of groundwater-dependant waterholes (springs) have been identified as occurring in the greater Carrapateena and Lake Torrens region. Groundwater drawdown during the Life-of-Mine is predicted to occur at only two of these, namely Euro Spring and Gorge Spring, both located on Salt Creek, which are likely to be fed, in part, from the Whyalla Sandstone Aquifer (WSA). This can be emphasised by the lack of aquatic flora and fauna at these groundwater springs during most surveys, before reappearing when water conditions improve; which coincides with high rainfall events. This indicates that these watercourse springs are temporary refuges rather than long term key population sources. The Project Area is home to a variety of saline water and freshwater invertebrates that survive long periods of drought before rainfall stimulates their life cycle. Yabbies (Cherax destructor) have also been observed. Freshwater vertebrates such as the Lake Eyre Hardyhead (Craterocephalus eyresii) and the Painted Burrowing Frog (Neobatrachus sudelli) have been observed in the Project Area. None of the identifiable species has any state or national listing for conservation value. The impacts associated with a reduction in pooling in Gorge and Euro Springs or a change in water quality because of the removal of the groundwater component of these systems is assessed as not significant. This is because Euro and Gorge springs display extremely high salinity and pose no threat to the health of terrestrial fauna species. The infrequent nature of runoff and pooling results in these water bodies suggests that they are not essential to persistence of aquatic ecology in the study area, and thus no significant impacts are predicted.
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Change in Groundwater Quantity and Quality at GAB Springs
The nearest GAB Springs as discussed, which are deemed ecologically significant, are located more than 160 km to the north of the Olympic Dam mine. These springs are supported by groundwater discharge from artesian GAB aquifers that are not hydraulically connected to Stuart Shelf aquifers found within the Project Area. There are no impacts on the GAB Springs.
Seepage of Tailings
The potential for seepage from the TSF to the regional groundwater flow system and for transport of solutes has been assessed by advective particle tracking from the water table underneath the base of the TSF. After 5,000 years (year 7045), seepage pathlines emanating at the base of the TSF travel lateral distances of up to approximately 10 km; this represents average travel distances of 2 m/y.
The predicted pathlines from the THA beneath the TSF are captured by the subsidence zone lake. Seepage from the TSF within the THA does not reach Lake Torrens within 5,000 years of the completion of mining (year 7045) under modelled predictions.
Geochemical modelling was undertaken to assess mixing and migration of the TSF tailings liquor and groundwater to predict what chemical reactions may be occurring between the TSF liquor and the host aquifer. Results of the modelling are summarised below: Major ion concentrations within groundwater are of a much greater magnitude than the TSF liquor, to the extent that introduction of TSF liquor into native groundwater over a 100-year input is predicted to not significantly alter the major ion composition of the groundwater over the flow pathway. The native groundwater is naturally elevated with respect to metals, with concentrations in excess of that found in TSF liquor. The exception to this is the naturally occurring uranium (U) concentrations. Leach test trials of tailings material indicate some uranium is expected to leach from the tailings, with a maximum U concentration of 0.57 mg/L being reported during the stable period of the assessment. For context, the average U concentration (dissolved) as reported in baseline groundwater monitoring in the area is 0.001 mg/L, with a maximum concentration of 0.016 mg/L being reported. Uranium (as uranyl) will be present in solution predominantly as uranyl carbonate, with a maximum concentration of uranium (as uranyl) in solution of 0.063 mg/L over the flow path distance assessed (500 m at 60 years). The concentration of uranium (as uranyl) in solution is predicted to be 0.02 mg/L at approximately 7.5 km away from the TSF (linear flow) after 3,700 years. Majority of the uranium (approximately 80%, as uranyl) will be sorbed to the mineral surfaces within the THA, noting the predominantly quartz based structure of the aquifer. Several uranium mineral phases are predicted to be over-saturated, meaning that they are likely to form within the system.
The predominant mineral phases are uranophane (Ca(UO2)2(SiO3OH)2.5(H2O)), a mineral of the uranyl silicates group, and the major uranium ore, uraninite along with coffinite. A guideline criterion for uranium in water is available within the ANZECC (2000) water quality guidelines with respect to use of water for livestock purposes (0.2 mg/L). This criterion is above both the maximum natural background uranium concentration of 0.016 mg/L and the predicted
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concentration of uranyl in solution at 500 m from the TSF (0.063 mg/L). It is important to note that the salinity of the groundwater is significantly high and is not suitable for stock watering.
The major ion content in groundwater is of a much greater magnitude than the TSF liquor, to the extent that significant changes in major ion composition in groundwater because of a 100 year input of TSF liquor directly to groundwater is not predicted to significantly alter the major ion composition of the groundwater. Geochemical modelling indicates that compositional changes to groundwater assuming TSF seepages mixes with the THA are not expected beyond 500 m from the TSF, and thus water quality at Lake Torrens, third-party users and watercourse springs will not be impacted.
Third-Party Users
Discussions with pastoralists suggest wells have limited capacity to supply water, particularly during summer months. Investigations within the Study Area indicate there is no third-party demand on regional groundwater resources, most likely due to high salinity concentrations. On a regional scale, groundwater salinity concentrations greatly exceed what would be tolerated by stock. Stock water supplies from surface water supplies are supplemented by groundwater abstracted from perched aquifers within shallow sediments, there being a large difference in water quality between the stock sources and the water quality from the shallowest regional THA.
Groundwater drawdown will be restricted to the THA and WSA and depressurisation will not reduce groundwater quantity in the shallow groundwater lens found within quaternary sediments that rely on recharge from creek flows and/or rainfall vents. Therefore, there are no predicted effects at third-party wells used to supplement stock water supplies based on the shallow perched groundwater lens conceptualisation.
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3.3.3 Air Quality
The proposed Project is situated in a rural, remote area, with the air environment characterised by clean air. Baseline ambient air quality is summarised in Table 3.14 and the data collected is typical of an arid area dust environment. The primary baseline air pollutant that occurs within the Project Area is airborne particulate matter, with particle types ranging from smaller particles transported from large distances well outside the regional area, to particles with a larger crustal dust particle component emitted from local sources. The local emissions are generally associated with erosion of unpaved roads and exposed surfaces, mineral exploration and agricultural/pastoral activities.
Baseline radiation surveys were undertaken to characterise the naturally occurring radiation in the region. Fifteen Environmental Radiation Monitoring Locations (ERMLs) were established in the Project Area during 2012 and 2013, and were located in consideration of: The most likely areas of future mining activities The sensitive receptors located closest to the proposed mining activities To minimise interference from road traffic.
The monitoring comprised measurement and analysis of gamma radiation, radon gas concentrations and deposited dust, with results shown in Table 3.15.
Table 3.14: Summary of Baseline Air Quality Monitoring
Carrapateena Size Fraction Averaging Period Value 3 PM2.5 Annual 1.0 – 7.7 μg/m
24-hour 3.9 μg/m3
3 PM10 Annual 13.0 μg/m
24-hour 3.0 – 23.0 μg/m3
Total Suspended Particulate (TSP) Annual 26 μg/m3
Dust Deposition Annual 1.6 g/m2/month
Table 3.15: Summary of Baseline Environmental Radiation Monitoring
Location Gamma Radon Passive Dust (Bq/m2/month) (μSv/h) (Bq/m3) U238 Th230 Ra226 Po210 Pb210 Carrapateena 0.02–0.17 <10-23 0.01–0.46 0.02–0.57 0.01–0.28 0.47–3.85 0.30–4.26 ERMLs
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Modelling Overview Air quality modelling undertaken to support the Mining lease Proposal was undertaken to determine the change in the baseline air quality as a result of the proposed Project activities. The air quality modelling for the proposed development had two main components: The development of representative source emission rates The modelling of the emissions sources with consideration to local meteorology and topography.
The meteorological and air dispersion modelling methodology was undertaken in accordance with South Australia’s Environmental Protection (Air Quality) Policy 2016 and the associated assessment guideline. The modelling methodology comprised three main elements: Generation of 3-dimensional, hourly-varying meteorological data using the CSIRO ‘TAPM’ model. Using the TAPM-generated meteorological data as an input to the ‘Calmet’ meteorological model, generating a second meteorological dataset. Using Calmet-generated meteorological data as an input to the ‘Calpuff’ air dispersion model.
A post-processing programme (‘Calpost’) was used to extract statistical results from the Calpuff- generated pollutant dispersion data. The results were provided as plots of concentration isopleths (contours), representing ground-level air pollutant concentrations and deposition rates.
For quantifying the potential health impacts to human receptors, the results were also compared against relevant air quality criteria.
Nature and Extent of Likely Impact Air Quality
Analysis of Project-related pollutant concentrations against relevant human health-related criteria indicates that compliance will be achieved within 1-7 km of Project-related activities. Thus modelling demonstrates that human receptors (i.e. Pernatty Homestead, located 25 km to the south of the main Project activities) are located outside of the predicted area of Project-related air quality changes and thus human health values will not be impacted.
Gaseous Emissions
Air Quality modelling of gaseous pollutants indicate that increases in concentrations would be limited to the immediate vicinity of the operation, extending up to approximately 16 km from the operations at their peak. The relevant air quality criteria for gaseous pollutants is not predicted to be exceeded at any point within or outside of the proposed tenements. The dominant vegetation cover has leaf structure that is highly resilient to gaseous pollutants, having a mealy surface coating or dense hair, and therefore no significant impacts are predicted.
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Dust Deposition
Existing dust deposition (including the deposition of regionally generated saline aerosols) averages approximately 1.6 g/m2/month across the Project Area. Significant additional Project-related dust deposition will be confined to the immediate 500 m surrounding the dust-generating operations, the area affected reducing to approximately 200 m following closure. Dust totals of approximately 7 g/m2 are deemed the level at which changes in plant health become evident and the actual impact is likely to be variable based on the period between rainfall events and high wind speed events, which remove dust deposition from the leaf surface. It would therefore require several months without rainfall before some species may begin to demonstrate impacts, and the significance of these impacts are expected to be only slightly greater near the operations versus across the baseline environment. The transport of concentrate will be undertaken in dedicated containers that will prevent dust emissions during transport. There are no significant impacts predicted to identified receptors as a result of dust deposition.
Acid Mist Emissions
Acid mists generated during the concentrate treatment process would be scrubbed prior to emission to atmosphere. This is considered a Fundamental Design Control and thus there is considered no linkage between the source, pathway and receptor and therefore no impact to receptors.
Radon Emissions
Radon concentrations are expected to be virtually indistinguishable from natural background variation and thus no impacts are expected because of exposure to radon to flora, fauna or the public.
Radionuclides
Exposure to radionuclides in dust was assessed and the results indicating that expected radiation exposures did not meet the investigation threshold concentration. As a result, no impacts are expected to flora, fauna or the public.
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3.3.4 Soil and Vegetation Characteristics
The proposed Project is situated in the Gawler Interim Biogeographic Regionalisation for Australia (IBRA) Bioregion, the Arcoona Plateau Sub-region and the Andamooka IBRA Environmental Association. Additionally, the Western Infrastructure Corridor linking the proposed Mining Lease to the Stuart Highway passes through the Gawler Lakes IBRA Sub-region. The Gawler Bioregion is located between Woomera and the edge of Lake Torrens, and comprises one quarter of South Australia’s Pastoral Rangelands, encompassing an area of 123,070 km2. The Project Area is immediately west and south of the Carrapateena arm of Lake Torrens, which is an inland salt lake and National Park proclaimed under the National Parks and Wildlife Act 1972 (SA). A summary of the soil and vegetation characteristics in the Project is provided in Table 3.16. Vegetation associations within the Project Area are described in Section 3.3.1.
Table 3.16: Bioregion, Sub-region, and Environmental Association Environmental Landscape Summary
Gawler IBRA bioregion Characterised by semi-arid to arid, flat topped to broadly rounded hills of the Gawler Range Volcanics and Proterozoic sediments, low plateaux on sandstone and quartzite with an undulating surface of aeolian sand or gibbers and rocky quartzite hills with colluvial footslopes, erosional and depositional plains and salt encrusted lake beds, with black oak (belah) and myall low open woodlands, open mallee scrub, bluebush/saltbush open chenopod shrublands and tall mulga shrublands on shallow loams, calcareous earths and hard red duplex soils. Arcoona Plateau IBRA sub-region A series of low plateaux on sandstone and quartzite with an undulating surface of aeolian sand or gibbers over red duplex soils, and rocky quartzite hills with colluvial footslopes. There is a cover of low chenopod shrubland, Acacia victoriae tall shrubland with a chenopod shrub understorey and fringing Acacia papyrocarpa woodland. Approximately 97% (1,153,042 ha) of the sub-region is mapped as remnant vegetation, of which 0.1% (1,143 ha) is formally conserved. Sub-region consists of a dissected sandstone plateau with a bold eastern escarpment. Surface is undulating to hilly and often gibber-covered, particularly in the east, and consists of crusty red duplex soils and red calcareous loams. Vegetation is generally Chenopod shrublands. Gawler Lakes IBRA sub-region An undulating upland plain underlain by quartzite and sandstone, with shallow loamy soils. Encompasses the Woomera plateau, which is characterised by the absence of trees and tall shrubs, except on floodplains, where mulga (Acacia aneura), bullock bush (Alectryon oleifolius ssp. canescens), occasional red gums (Eucalyptus camaldulensis) and other species may be found. The gibber-covered areas are either bare or carry a scattered growth of samphire (Halosarcia sp.) and bindyi (Sclerolaena sp.). The depositional plains to the south and southwest of the plateau are covered with deep calcareous earths characteristically carrying an open myall (Acacia papyrocarpa) woodland with a bluebush (Maireana sedifolia) understorey, or red aeolian sand sheets and dunes with open mulga shrubland or a low woodland of Casuarina pauper or Callitris glaucophylla. Approximately 62% (1,271,089 ha) of the subregion is mapped as remnant native vegetation, of which 2% (30,615 ha) is formally conserved. Undulating plains overlain with sand sheets and dunes, with occasional silcrete capped rises with brown calcareous earths, crusty loamy soils with red clayey subsoils, Sand soils, brown and red, shallow dense loams.
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Torrens IBRA sub-region Plain adjacent to Lake Torrens, covered by dune formations with relatively small plains between. Numerous partly connected lakes and pans. Sandy alluvial plain beneath dunes. Dominated by dune sand and sand mantles; alluvial sand, silt and clay; evaporites (gypsum and halite); some kopi dunes and low rises; gilgai and stony plains; clay and silt deposits in dune corridors. Brown calcareous earths, crusty loamy soils with red clayey subsoils, loamy soils with weak pedologic development. Andamooka IBRA association Remnant vegetation Approximately 98 % (490,526 ha) of the subregion is mapped as remnant native vegetation, of which 0.2 % (1,072 ha) is formally conserved. Landform Gibber covered plateau with irregular surface and steep bounding slopes. Geology Quartzite, colluvium, sand and alluvium. Soil Powdery red calcareous loams, crusty red duplex soils and reddish sands. Vegetation Chenopod shrubland of saltbush and plover daisy, tall shrubland of mulga and turpentine mulga, woodland of river red gum and chenopod shrubland of samphire.
3.3.5 Outstanding Natural Features
The Project Area consists of an extensive tableland that forms the Arcoona Plateau. The Arcoona Plateau has a dendritic drainage pattern of short channels radiating from the tablelands onto lower lying areas, with wide shallow drainage channels in the upper parts and incised creeks in the lower parts. Lake Torrens and Pernatty lagoon have been identified as two outstanding features of the environment. These two features are clearly identifiable on Figure 1.1. As discussed in Section 3.3.2 there are no significant impacts predicted on Pernatty Lagoon or Lake Torrens and a result of changes in surface water or groundwater quantity or quality.
Lake Torrens Lake Torrens is situated between the Flinders Ranges to the east, where the maximum topographic elevation is approximately 1,150 mAHD, and the Arcoona Plateau to the west, where the elevation is approximately 150 mAHD. The surface elevation of the bed of Lake Torrens is approximately 30 mAHD. The feature is an ephemeral playa lake within an endorheic basin, i.e. there is no outflow of water. The Lake is usually dry, having filled with water only once in the past 100 years (in 1989).
The largest creek catchment to terminate at Lake Torrens is Willochra Creek, which flows north-west from Mount Remarkable in the southern Flinders Ranges and across the Willochra Plain before reaching the southern end of Lake Torrens. Only a small percentage of rainfall runs off the catchment, and the surface water balance is dominated by rain landing directly on the lake surface.
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Pernatty Lagoon Pernatty Lagoon is an ephemeral salt lake, fringed by sand dunes, located to the west of Lake Torrens, and is located to the south of the Western Infrastructure Corridor. The salt lake has a surface area of 209 km2 and a catchment of 1,730 km2. The largest creeks terminating at Pernatty Lagoon are Elizabeth Creek, which terminates at the northern end of the lagoon, and Pernatty and Yeltacowie Creeks that terminate at the southern end of the lagoon.
3.3.6 Remnant Native Vegetation
The Project Area contains remnant vegetation in good condition with evidence of minor grazing pressures and very low weed cover. Refer to Section 3.3.1 for descriptions of the vegetation associations found in the Project Area.
3.3.7 Gradient (or depth range if action is to be taken in a marine area)
The Project Area lies on the Arcoona Plateau (see Section 3.3.4), which forms an extensive tableland and no activities are proposed in a marine area.
3.3.8 Current State of the Environment
The environment of the Project Area is generally in good condition, within the context of a working pastoral station. There is good native vegetation cover and flora and fauna diversity typical of a semi- arid system. In general, the semi-arid zone supports few pest plants and very few weeds were recorded during the series of ecological surveys of the Project Area as described in Appendix 2 – Ecological Baseline Assessment. Weed species recorded across the whole Project Area are listed in Table 3.17.
Table 3.17: Project Area Recorded Pest Plant and Weed Species
Significance Species Name Common Name National State NRM Acetosa vesicara Rosy Dock N N N Bidens pilosa Cobbler’s Pegs N N N Carthamus lanatus Malta Thistle N N N Citrullus lanatus Bitter Lemon N N N Flaveria trinervia Clustered Yellowtops N N N Tribulus terrestris Caltrop N N N Mesembryanthemum nodiflorum Slenderleaf Iceplant N N N Centaurium erythraea Common Centaury N N N Centaurium melitenis Cockspur thistle N N N Nicotania glauca Tree tobacco N N N Schismus barbatus Arabian Grass N N N Brassica tournefortii Wild Turnip N N N Carrichtera annua Wards Weed N N N
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Significance Species Name Common Name National State NRM Sonchus oleraceus Common Sowthistle N N N Physalis. sp Nightshade N N N Rostraria pumila Tiny Bristle Grass N N N Echium plantagineum Patterson’s Curse N Yes N Solanum linnaeanum Apple of Sodom N N N Centaurea calcitrapa Golden Starthistle N N N Xanthium spinosum Bathurst Burr N Yes N Heliotropium sp. Blue Heliotrope N N N Lepidium africanum Common Pepper-cress N N N Sisymbrium erysimoides Smooth Mustard N N N Citrullus colocynthis Camel Melon N N N Malva parvifolium Mallow N N N National: Australia (Weeds of National Significance) State: South Australia (Declared pest plants Natural Resources Management Act 2004) NRM region: South Australian Arid Lands (Priority Weeds of the SAAL Region) A number of exotic species have been observed across the Project Area during the surveys. Goats (Capra hircus), sheep (Ovis aries), European Rabbits (Oryctolagus cuniculus), House Mouse (Mus musculus), Cats (Felis catus) and Red Foxes (Vulpes vulpes) are all recorded within the Project Area (see Table 3.18). All of these species are widespread throughout Australia and are commonly observed throughout much of the arid lands of South Australia. Areas of permanent water, availability of alternative food resources such as around human centres and unauthorized feeding may indirectly facilitate the increase in abundance of pest species. Pest animals potentially arrive through transport vectors. Pests already present such as cats, and foxes are aided by the presence of exotic birds and mice.
Table 3.18: Project Area Recorded Pest and Feral Animal Species
Significance Species Name Common Name National State NRM Mus musculus House Mouse D Felis catus Feral Cat KTP, TAP D K Vulpes Vulpes Red Fox KTP, TAP D K Oryctolagus cuniculus European Rabbit KTP, TAP D K Passer domesticus House Sparrow D Canis lupus familiaris Feral Dog D
National: Australia (EPBC Act 1999 and Australian Pest Animal Strategy 2007); State: South Australia (declared animal pests Natural Resources Management Act 2004); NRM region: South Australian Arid Lands (key pest species of the SAAL Region) KTP: Key Threatening Process, TAP: Threat Abatement Plan, D: Declared K: Key Pest Species
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3.3.9 Commonwealth Heritage Places or Other Places Recognised as Having Heritage Values
The Protected Matters Search indicates there are no National Heritage Places located within the Project Area.
3.3.10 Indigenous Heritage Values
The Protected Matters Search indicates there are two indigenous heritage sites on the Register of the National Estate within the vicinity of the Project Area, the Yeltacowie Engraving Sites and the Yeltacowie Stone Arrangement. The Project footprint will not disturb sites on the Register of the National Estate.
A large focus of efforts during the design phase of the Project has been to ensure infrastructure locations have been selected in consultation with the Kokatha People. Consultation is undertaken through a series of surveys with the Kokatha People with assistance from a mutually agreed anthropologist. Surveys are undertaken in accordance with the heritage management procedures agreed under OZ Minerals’ current Native Title Mining Agreement.
OZ Minerals respects the rights of the Traditional Owners and their cultural values and Heritage. For this reason, the names, locations and maps of archaeological and anthropological sites have been removed from this document. Any reference to mythology and storylines that OZ Minerals has learnt through its partnering agreement with the Kokatha People has not been included. The importance of the area to the Traditional Owners has been considered in the Project design work, and the subsequent studies undertaken occur with ongoing and meaningful consultation.
3.3.11 Other Important or Unique Values of the Environment
The Protected Matters Report identified one State and Territory Reserve, and one Nationally Important Wetland, being the Lake Torrens National Park. Lake Torrens is not within the Project Area, however it falls within the buffer used for the Protected Matters Search. The assessment for the Project has incorporated extensive studies of the potential impact to Lake Torrens, and is described throughout this Referral where relevant. Lake Torrens is considered a component of the Inland Saline Lakes complex within the Directory of Important Wetlands in Australia.
In addition, a number local and regional environmental values were highlighted throughout the course of stakeholder engagement for the Project. The key value raised was the importance of Lake Torrens for its environmental value and cultural significance. Surface water, and particularly flows around Eliza Creek valley associated with the TSF location, was queried by stakeholders, as was groundwater quality and quantity associated with flows to Lake Torrens, watercourse springs and pastoral uses.
Further feedback was provided around specific environmental values through a Stakeholder Feedback Survey. In terms of environmental values, stakeholders referred to the importance of environment and sustainability, including the need to preserve native species and protect the environment; and the importance of managing potential environmental impacts of projects for values such as groundwater, surface water and air quality.
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3.3.12 Tenure of the Action Area (e.g. freehold, leasehold)
Existing disturbance within the Project Area is limited to exploration and Retention Lease (RL) related works, and disturbance associated with pastoral activities including grazing impacts and grazing related infrastructure such as tracks and fences. The underlying tenure of the action area for each proposed tenement is summarised in Section 1.3.
3.3.13 Existing Land/Marine Uses of Area
The proposed tenements lie within the Pernatty and Oakden Hills Pastoral Leases, which share boundaries with Bosworth, Arcoona and South Gap Pastoral Leases. The Pastoral Leases are predominantly used for sheep grazing, however limited water resources in the area necessitate low stocking rates and some areas are only grazed when surface water is present in dams, creeks and waterholes.
The Arcoona Plateau has had a long history of grazing by native, domestic and feral herbivores, as well as being subject to the operations and infrastructure of sheep and cattle stations.
The Western Infrastructure Corridor also intersects a freehold parcel of land owned by WMC (Olympic Dam Corp) Pty Ltd. The parcel contains a transmission line that connects Olympic Dam to the Davenport substation.
The proposed tenements also overlap with other third-party land exploration licences as shown in Figure 1.5. Under the Mining Act. Exploration Licences authorise the licensee to explore for all minerals and/or opal other than extractive minerals. Dual Tenement Agreements are required between OZ Minerals and the EL holders. The Dual Tenement Agreements will ensure that exploration activities can continue and will consider any potential future resource identification. If any potential future resource was identified under the proposed infrastructure, OZ Minerals would relocate infrastructure to enable mining of any identified and approved resource.
3.3.14 Any Proposed Land/Marine Uses of Area
There are no known plans for future changes in land use by other parties for the local area surrounding the proposed tenements.
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4 ENVIRONMENTAL OUTCOMES
As outlined in Section 1.11 and Section 2.5 of this referral, the proposed action requires approval under the Mining Act, including submission of a Mining Lease Proposal and Miscellaneous Purposes Licence Management Plans.
The State of South Australia requires that the MLP provide a statement of proposed draft outcomes based on the assessment undertaken in the MLP. Following submission and approval of the MLP (and associated MPL Management Plans) by the Government of South Australia, and the subsequent granting of the ML and MPL tenements, OZ Minerals has a regulatory requirement to submit a Program for Environment Protection and Rehabilitation (PEPR). The PEPR describes the criteria required to measure the environmental and community outcomes committed to including matters of National Environmental Significance, where relevant, and provides the regulators with the structure of OZ Minerals’ capability to manage the mining operation adequately to meet the environmental criteria. The PEPR meets the statutory requirements for environmental management under the Mining Act.
In alignment with the proposed draft outcomes, OZ Minerals will have recommended, where required, Leading indicators and Outcome Measurement Criteria for different scenarios.
An Outcome Measurement Criterion summarises the measurement method, frequency, location and outcome achievement that is used to measure performance against a stated outcome description.
A Leading Indicator is required when there is a high reliance on a control strategy to achieve the outcome. A leading indicator is used to give an early warning that a control strategy may fail or be failing, to enable OZ Minerals to undertake actions to prevent the control strategy from failing to achieving the outcome.
Throughout this assessment, it has been demonstrated that the proposed action is not likely to significantly impact on Matters of National Significance or present any significant impacts to the broader environment as discussed in Section 3. Therefore, no proposed draft outcomes relating to Matters of National Significance are proposed.
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5 MEASURES TO AVOID OR REDUCE IMPACTS
OZ Minerals has considered the role of design and management controls in the assessment process. The hierarchy of controls (see Figure 5.1) outlines how controls are applied during the phases of a project and the assessment process.
The hierarchy of controls has been used as a tool to drive continual improvement and minimise impacts in line with the principle of ‘so far as is reasonably practicable’ (SFAIRP). When assessing controls, the hierarchy of controls and the corresponding increasing effectiveness must be considered for the project. Elimination, Substitution and Engineering are all considered Design Controls. OZ Minerals utilises the early stage of project planning and engineering studies to work through the Elimination and Substitution levels of the hierarchy. Elimination has been utilised significantly across the Carrapateena Project, with examples such as avoiding areas of high cultural significance and habitat retreats for threatened species.
Engineering controls can be either active or passive, where passive controls are those that do not need operators to be present to ensure their ongoing effectiveness. Efforts are made to ensure those controls required at closure are passive.
Management measures implemented during construction and operation are generally administrative controls, behaviour controls and the use of protective equipment, and are traditionally related to risk reduction. These form a large part of the on-site operating systems and management capability of OZ Minerals.
During the planning and design phase, there has been a strong focus on risk and impact elimination within the hierarchy of controls to ensure site selection has been carefully considered against the baseline environment. This has included avoidance of critical habitats and sites of cultural heritage significance, and avoidance of Matters of National Environmental Significance. The goal of reducing impacts to SFAIRP has driven the decision making process for the Project. Examples of design and management controls aimed at preventing or reducing impacts are summarised in Table 5.1 and Table 5.2.
Carrapateena Project / March 2017 Page 145 of 172 PROJECT PHASE CONTROL TYPE ASSESSSMENT PROCESS EFFECTIVENESS PERSONNEL RELIANCE
Most effective Least reliance ELIMINATION Design it out Avoid potential impact Iterative Engineering Design Processes DESIGN CONTROLS SUBSTITUTION Scoping Study and Use something else Pre-feasibility Study
ENGINEERING DESIGN CONTROLS Layers of Protection Isolation and guarding Analysis (LOPA) Active or passive
ADMINISTRATIVE CONTROLS Procedures and work scheduling
So Far As Is MANAGEMENT CONTROLS BEHAVIOUR Reasonably Practicable Construction and Operation Training and management (SFAIRP) and Risk
PERSONAL PROTECTIVE EQUIPMENT Last resort Least effective Most reliance
Figure 5.1: Hierarchy of Controls
CARRAPATEENA PROJECT Carrapateena Project EPBC Referral of Proposed Mining Lease and Associated Tenements
Table 5.1: Summary of Design Controls
Design Controls Air Quality Enclosed copper concentrate transport containers Acid mist scrubbers on Concentrate Treatment Plant Rock armouring of final TSF embankment landform Surface Water Separation of overland surface water flows originating from undisturbed areas within the Project Area from the surface water run-off that has interacted with disturbed land. Hydrocarbon and chemical storage facilities will be designed in accordance with Australian Standards and EPA guidelines. Fuel and lubricant storage and dispensing facilities will be designed and installed in accordance with Australian Standards and EPA guidelines. Vehicle wash downs installed, and will be bunded and the wash water recycled within the wash-down area. Roads within the mine site will be constructed with fords where possible to allow for natural movement of surface water runoff. Road culverts, diversion drains, bunding and sedimentation/event basins designed and installed in accordance with a Best Practice Operating Procedures endorsed by the SA Arid Lands Natural Resources Management Board or a Water Affecting Activity Permit under the Natural Resources Management Act 2004 (SA). TSF embankment and decant collection dam and ponds designed and operated in accordance with ANCOLD standards and other relevant guidelines. TSF placement in upper catchment reducing effects on pre-mine surface water flows and reducing the volume of captured run-off requiring management. Land Avoidance of critical habitat during site selections. Avoidance of sites of cultural heritage significance in consultation with the Kokatha People. Hydrocarbon and chemical storage facilities will be designed in accordance with Australian Standards and EPA Guidelines.
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Table 5.2: Summary of Management Controls
Management Controls Air Quality Dust suppression on disturbed land Dust suppression on unsealed roads Dust suppression systems on crushing operations Dust suppression water sprays on Course Ore Stockpile Dust suppression at conveyor transfer points Surface Water Culvert maintenance program Surface water diversion drains maintenance program Decant ponds and other key water infrastructure ponds freeboard maintenance program Regular inspection programs where bunding either temporary or permanent is installed to ensure appropriate use, placement of spill kits, clean up procedures and handling procedures Incident response and spill management procedures Operational control of the evaporation pond areas (e.g. through terracing) to allow for increasing or reducing the evaporation pond area to suit prevailing climatic conditions (e.g. smaller evaporation pond areas in summer when evaporation rates are higher) Temporary sediment and erosion controls (e.g.: mobile sediment booms, sediment fencing) Land Land disturbance approval process including cultural heritage approval GIS system to record / identify clearance areas and status Progressive rehabilitation of disturbed land Identification and fencing of sites of cultural heritage significance Vehicle Wash-down Procedures Weed eradication programmes Weed red Alert List for quick identification Chemicals and hydrocarbons managed in accordance with relevant Australian Standards Storages bunded in accordance with EPA Bunding Guidelines and/or relevant Australian Standards Spill and emergency response procedures Access area gatehouse and appropriately signposted, stock fencing of TSF and processing area and early establishment of the SLC subsidence zone abandonment bund Feral animal control program Wherever possible, open excavations and drill holes will be covered as soon as practicable or managed to ensure no entrapment can occur through the use of ramps Vehicle movements will be limited to existing tracks Groundwater Reclaimed TSF supernatant water Reclaimed mine dewatering water Reclaimed treated effluent Abstraction and Injection Management Procedures Telemetric controls and flow meters to monitor abstraction rates Progressive update of numerical groundwater model Wellfield construction procedures
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6 CONCLUSION ON THE LIKELIHOOD OF SIGNIFICANT IMPACTS
6.1 Do you THINK your proposed action is a controlled action?
OZ Minerals does not think the proposed action is a controlled action.
6.2 Proposed action IS NOT a controlled action
A detailed review of the types and extents of the likely impacts concludes that the Project is NOT likely to have a significant impact based on: No observations during extensive site surveys carried out every autumn and spring since 2012 of listed threatened species including Amytornis modestus (Thick-billed Grasswren), Calidris ferruginea (Curlew Sandpiper), Pezoporus occidentalis and (Night Parrot) and Frankenia plicata (Sea-heath). No preferred habitat for these species exists within the Project disturbance footprint. The abundance of habitat available for the listed Plains Mouse in the region and the avoidance of key ecological areas and core habitat (cracking clay, gilgais habitat and swamp cane grass) means that the Project will not significantly reduce or fragment available habitat and is therefore unlikely to have a significant impact. For those migratory species that may interact with surface water storages, no significant impacts are likely as the water will generally be unpalatable. In the unlikely event that migratory species interact or ingest water, the pH is above 4.5 and a comparison of water quality against relevant criteria indicates that no significant impacts are likely. The Environmental Risk from Ionising Contaminants: Assessment and Management (ERICA) assessment demonstrates that there is no radiological risk to reference plants and animals from emissions from the proposed Project, therefore there will be no radiological impacts from the Project on non-human biota. Radiological assessments demonstrate that radiation exposures to members of the public will be a fraction of the regulatory limit of 1 mSv/y and result in negligible radiological impacts to the public.
The SA Government will also undertake a rigorous review of the OZ Minerals environmental impact assessment in accordance with the SA Mining Act. The Mining Act regulates and controls mining operations in South Australia and is regulated by DSD on behalf of the Minister for Mineral Resources and Energy (Minister). The process requires the assessment of environmental impacts and the development of environmental outcomes to minimise potential environmental impacts.
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7 ENVIRONMENTAL RECORD OF THE RESPONSIBLE PARTY
Table 7.1 summarises the management capability and environmental record of OZ Minerals.
Table 7.1: Environmental Record and Management Capabilities EPBC Referral Question Yes No Does the party taking the action have a satisfactory record of responsible environmental management? Provide details Yes. OZ Minerals currently operates an open pit copper/gold mine and processing plant at Prominent Hill. Transparent and accountable reporting of environmental performance is provided through the OZ Minerals annual Sustainability Report. The Prominent Hill operation has reported no significant environmental incidents. The OZ Minerals - Prominent Hill Environmental Management System (EMS) provides a framework to manage environmental risks and respond to environmental incidents. The Carrapateena Project will have an established Environmental Management System modelled on the Prominent Hill EMS. The OZ Minerals Corporate Sustainability Policy for 2016 is located on the Internet at www.OZMinerals.com. Has either (a) the party proposing to take the action, or (b) if a permit has been applied for in relation to the action, the person making the application - ever been subject to any proceedings under a Commonwealth, State or Territory law for the protection of the environment or the conservation and sustainable use of natural resources? If yes, provide details OZ Minerals received a Pollution Abatement Notice (PAN) in 2010 from the Northern Territory Department of Natural Resources, Environment, The Arts and Sport (NRETAS) in relation to the loading of its copper concentrate on ships at the Darwin Harbour. To improve environmental standards and mitigate risks, OZ Minerals has implemented a new system of handling copper concentrate onto ships using specifically designed containers and rotainer infrastructure. Following this significant investment to mitigate environmental risks, the PAN was lifted. Outside the operational control of OZ Minerals, a single moderate incident occurred on the 27 December 2011 when a mixed freight rail train operated by Genesee & Wyoming was derailed in a flood event at Edith River, approximately 50 km north of Katherine in the Northern Territory. The incident resulted in approximately 1,200 tonnes of OZ Minerals’ copper concentrate entering the flooded Edith River. OZ Minerals recovered a significant amount of concentrate, which was returned to Prominent Hill. The prompt activation of its Emergency Response Plan enabled OZ Minerals to respond to the derailment in a timely and appropriate manner. The site has now been rehabilitated to the satisfaction of all stakeholders. To improve environmental standards and mitigate potential risks, OZ Minerals has implemented a new system of handling and transporting copper concentrate. The system involves the use of specially designed containers to transport copper concentrate from Prominent Hill to ports in Adelaide and Darwin. The initial response and measures implemented to mitigate risks demonstrates OZ Minerals’ commitment to responsible environmental management.
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EPBC Referral Question Yes No If the party taking the action is a corporation, will the action be taken in accordance with the corporation’s environmental policy and planning framework? If yes, provide details of environmental policy and planning framework The OZ Minerals Environment and Community Policy is a statement by the organisation of its overall intentions and direction in relation to delivering sound environmental outcomes whilst supporting the creation of shared value for the communities in which we operate. The policy is signed off by OZ Minerals Managing Director and CEO and is reviewed annually to ensure its ongoing suitability, adequacy and effectiveness to support OZ Minerals’ core values of Respect, Integrity, Action and Results. The OZ Minerals Corporate Policies are located online at www.OZMinerals.com. The planning framework for the Carrapateena Project will be aligned to ISO14001, requiring the implementation and maintenance of processes for: Identifying the environmental aspects of OZ Minerals’ activities, products and services to determine those aspects that have, or can have, significant impact(s) on the environment; Identifying and assessing applicable legal and other requirements to which OZ Minerals subscribes and determining how these requirements relate to environmental aspects; Establishing, implementing and maintaining environmental objectives and targets at OZ Minerals; and Establishing, implementing and maintaining environmental management programmes for achieving OZ Minerals’ environmental objectives and targets. OZ Minerals currently operates an open pit copper/gold mine and processing plant at Prominent Hill. Prominent Hill has an established Environmental Management System. The Carrapateena RL activities are carried out in accordance with an Environment and Community Management Plan. Has the party taking the action previously referred an action under the EPBC Act, or been responsible for undertaking an action referred under the EPBC Act? Provide name of proposal and EPBC reference number (if known) OZ Minerals has previously referred the Prominent Hill project. 2005/2040: OXIANA LIMITED/Mining/Prominent Hill/South Australia/Prominent Hill Copper-Gold Project. 17/03/2005. Controlled Action 2006/2962: Oxiana Limited/Mining/Prominent Hill/SA/Prominent Hill construction well-field development. 28/07/2006. Not a Controlled Action 2006/3110: OXIANA LIMITED/Energy Generation and Supply (non-renewable)/Prominent Hill/South Australia/132kV Electricity Transmission Line for the Prominent Hill Copper-Gold Project. 24/10/2006. Not a Controlled Action 2007/3323: OXIANA LIMITED/Mining/Parkside/South Australia/Concentrate Export Road for Prominent Hill Copper-Gold Project. 5/03/2007. Not a Controlled Action 2007/3490: OXIANA LIMITED/Mining/Prominent Hill/South Australia/Operations Wellfield Infrastructure Corridor. 5/06/2007. Not a Controlled Action 2007/3683: Oxiana Limited/Mining/Prominent Hill /SA/Prominent Hill Copper-Gold Project Operations Wellfield. 3/09/2007. Not a Controlled Action
OZ Minerals has previously referred the Advanced Exploration Works for the Carrapateena Deposit Reference No. EPBC 2012/6494. Not a Controlled Action.
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8 INFORMATION SOURCES AND ATTACHMENTS
8.1 References
Absensperg-Traun, M. and Dickman. C.R. 1989. ‘Distributional ecology of Red-capped Plover, Charadrius ruficapillus (Temminck, 1822), on Western Australian salt lakes’. Journal of Biogeography 16 (2), pp 151-157.
Australian and New Zealand Environment and Conservation Council. 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Volume 3. Primary Industries – Rationale and Background Information (Chapter 9). October 2000.
Australian National Committee on Large Dams. 1999. Guideline on Tailings Dam Design, Construction and Operation, ANCOLD Publications, Tatura, Victoria.
Australian National Committee on Large Dams. 2012. Guidelines on Tailings Dams: Planning, Design, Construction, Operation and Closure. May 2012.
Australian Radiation Protection and Nuclear Safety Agency. 2010. Environmental Protection: Development of an Australian approach for assessing effects of ionising radiation on non-human species. Technical Report Series No. 154. Australian Radiation Safety and Nuclear Safety Agency.
Badman, F.J. 1989. The Birds of Middle and Lower Cooper Creek in South Australia. Nature Conservation Society of South Australia, Adelaide.
Bamford, M., Chuk, K., and Everard, C. 2014. Review of impact of pit void lakes upon fauna: Kintyre Uranium Project. Western Australia, Australia.
Bamford, M., Watkin, D., Bancroft, W., Tischler, G., and Wahl, J. 2008. Migratory Shorebirds of the East Asian - Australasian Flyway; Population Estimates and Internationally Important Sites. Wetlands International - Oceania. Canberra, Australia.
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8.2 Reliability and Date of Information
This referral has been prepared based on recent studies undertaken for the Carrapateena Mining Lease Proposal. The relevant studies are included as attachments to this referral. Further information on data sources, reliability and uncertainties can be found in each Appendix.
8.3 Attachments
The documents attached to this referral are described in Table 8.1.
Table 8.1: Attachments
Attachment Requirements Attached Title of Attachment Figures, maps or aerial photographs showing the Project locality (section 1) GIS file delineating the boundary of the referral area You must (section 1) attach Figures, maps or aerial photographs showing the location of the Project in respect to any matters of national environmental significance or important features of the environments (section 3) Copies of any state or local government approvals Not and consent conditions (section 2.5) applicable
Copies of any completed assessments to meet state Not or local government approvals and outcomes of applicable public consultations, if available (section 2.6) Copies of any flora and fauna investigations and Appendix 2 Ecological surveys (section 3) Baseline Assessment If relevant Technical reports relevant to the assessment of Appendix 3 Ecological attach impacts on protected matters that support the Impact Assessment arguments and conclusions in the referral (section 3 Appendix 4 Environmental and 4) and Public Radiation Impact Assessment Appendix 5 Occupational Radiation Assessment Report(s) on any public consultations undertaken, Not including with Indigenous stakeholders (section 3) applicable
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10 APPENDICES
Appendix 1 EPBC Act Protected Matters Report
Appendix 2 Ecological Baseline Assessment
Appendix 3 Ecological Impact Assessment
Appendix 4 Environmental and Public Radiation Impact Assessment
Appendix 5 Occupational Radiation Assessment
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