Mindarie Mineral Sands Project Mindarie C and A(2)
Program for Environment Protection and Rehabilitation (PEPR)
7 December 2011
Murray Zircon Pty Ltd
Parsons Brinckerhoff Australia Pty Limited ABN 80 078 004 798 Level 16 1 King William Street Adelaide SA 5000 GPO Box 398 Adelaide SA 5001 Australia Telephone +61 8 8405 4300 Facsimile +61 8 8405 4301 Email [email protected]
Certified to ISO 9001, ISO 14001, AS/NZS 4801 11-0773-06-2162559A A+ GRI Rating: Sustainability Report 2010 Revision Details Date Amended By 00 Original 30 September 2011 A Joubert 01 Working Draft 12 October 2011 J Wolfersberger 02 Working Draft 21 October 2011 J Wolfersberger 03 Working Draft 23 November 2011 J Wolfersberger 03 Working Draft 24 November 2011 P Gibbons 04 Working Draft 25 November 2011 P Gibbons 05 Working Draft 2 December 2011 P Gibbons 06 Draft 6 December 2011 P Gibbons 07 Draft 7 December 2011 A Eadie
©Parsons Brinckerhoff Australia Pty Limited [2011]. Copyright in the drawings, information and data recorded in this document (the information) is the property of Parsons Brinckerhoff. This document and the information are solely for the use of the authorised recipient and this document may not be used, copied or reproduced in whole or part for any purpose other than that for which it was supplied by Parsons Brinckerhoff. Parsons Brinckerhoff makes no representation, undertakes no duty and accepts no responsibility to any third party who may use or rely upon this document or the information. Author: Jean Wolfersberger ......
Signed: ......
Reviewer: Alex Eadie ......
Signed: ......
Approved by: Paul Gibbons ......
Signed: ......
Date: 7 December 2011 ......
Distribution: MZ, Parsons Brinckerhoff ......
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11-0773-07-2162559A Mindarie Mineral Sands Project – Mindarie C and A(2) – Program for Environment Protection and Rehabilitation (PEPR)
Contents
Page number
Acronyms ix
1. Introduction 1 1.1 Project history 1 1.2 Program for Environment Protection and Rehabilitation 2 1.2.1 Objectives and context 2 1.2.2 Structure and content of PEPR 3
2. Proponent details 5 2.1 Project proponent 5 2.2 Project location and mining tenements 5 2.3 Local government 6
3. Legislative requirements 7 3.1 South Australian legislation 7 3.1.1 Mining Act 1971 7 3.1.2 Natural Resources Management Act 2004 8 3.1.3 Environment Protection Act 1993 9 3.1.4 Development Act 1993 11 3.1.5 Native Vegetation Act 1991 11 3.1.6 National Parks and Wildlife Act 1972 11 3.1.7 Other relevant State legislation 12 3.2 Australian government legislation 15 3.2.1 Environment Protection and Biodiversity Conservation Act 1999 15 3.2.2 Other relevant Commonwealth legislation 15 3.3 National policies and strategies 15
4. Existing environment 17 4.1 Land use and proximity to housing and infrastructure 17 4.2 Noise, dust and air quality 18 4.2.1 Air quality 18 4.2.2 Noise 18 4.3 Topography and landscape 20 4.4 Climate 20 4.4.1 Rainfall, humidity, evaporation and wind 20 4.4.2 Temperature 21 4.5 Geohazards 22
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Contents (Continued)
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4.6 Geology and soils 23 4.6.1 Regional geology 23 4.6.2 Local geology 24 4.6.3 Soil 24 4.7 Surface water 29 4.8 Groundwater 29 4.8.1 Regional 29 4.9 Fauna and flora 31 4.9.1 Flora 31 4.9.2 Mindarie A(2) 35 4.9.3 Fauna 36 4.9.4 Pest plants and animals 38 4.10 Heritage 39 4.10.1 Indigenous heritage 39 4.10.2 Non-Indigenous heritage 40 4.11 Proximity to conservation areas 41 4.12 Pre-existing site contamination and disturbance 41 4.13 Socio-economic 41 4.14 Transport and traffic 42
5. Project description 43 5.1 General description and summary 43 5.1.1 General 43 5.1.2 Project schedule 45 5.1.3 Project alternatives 45 5.2 Resources, products and markets 48 5.2.1 Geological environment 48 5.2.2 Total operations ore reserves 48 5.2.3 Production rate, products and market 51 5.2.4 Material movement 51 5.3 Mining operations 52 5.3.1 General mine sequence 52 5.3.2 Site clearance 53 5.3.3 Native vegetation, topsoil and subsoil removal and stockpiling 53 5.3.4 Overburden removal and stockpiling 54 5.3.5 Mine pit details 55 5.3.6 Ore recovery 56 5.3.7 Slurry unit 57
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Contents (Continued)
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5.4 Processing 58 5.4.1 Primary concentrator plant 58 5.4.2 Process description 58 5.4.3 PCP components 59 5.4.4 Hours of operation 63 5.5 Tailings 63 5.5.1 Tailings characterisation 63 5.5.2 Tailings discharge 63 5.5.3 Tailings management 64 5.5.4 Tailings associated components 64 5.6 Sequence of mining and rehabilitation operations 65 5.6.1 Mining direction 65 5.6.2 Mining sequence and scheduling 65 5.6.3 Production schedules and annual production 65 5.7 Supporting mine infrastructure 65 5.7.1 Electricity 65 5.7.2 Pipelines 66 5.7.3 Ancillary infrastructure 67 5.7.4 Fuel storage 67 5.8 Road access and transport 68 5.9 Water management 68 5.9.1 Water supply 68 5.9.2 Mine water and tailings decant 71 5.9.3 Process water and tailings decant 71 5.9.4 Site run off/silt control and drainage 72 5.10 Waste and hazardous material management 74 5.10.1 Tailings/processing waste 74 5.10.2 Commercial and industrial waste 74 5.11 Stockpiles management 75 5.11.1 Topsoil and subsoil 75 5.11.2 Overburden 76 5.11.3 Heavy mineral concentrate 76 5.12 Construction 77 5.12.1 PCP relocation works 77 5.12.2 Access 77 5.12.3 Accommodation 77 5.13 Modes and hours of operation 78 5.14 Visual screening and site security 78 5.15 Plant and machinery requirements 78
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Contents (Continued)
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5.16 Resource inputs 79 5.16.1 Workforce details 79 5.16.2 Energy sources 80 5.17 Water sources 80 5.18 Mine completion and rehabilitation 80 5.18.1 Management of overburden 81 5.18.3 Rehabilitation 81 5.19 Mindarie A(2) and former Mindarie C rehabilitation 82 5.19.1 Planned rehabilitation works 82
6. Stakeholder consultation 85 6.1 Identified stakeholders 85 6.2 Australian Zircon stakeholder consultation 86 6.2.1 Murray Mallee Community Consultative Committee (Mineral Sands) 87 6.2.2 Aboriginal liaison 88 6.2.3 Consultation on the Mindarie C project by AZ 88 6.3 Stakeholder consultation during administration 89 6.4 Murray Zircon stakeholder consultation 89 6.4.1 Approach 89 6.4.2 Consultation to date 89 6.4.3 Ongoing consultation 94
7. Environmental outcomes 97 7.1 Background 97 7.1.1 Control and management strategies 97 7.1.2 Outcomes measurement criteria 98 7.1.3 Monitoring 98 7.1.4 Environmental outcomes and measurement criteria 98 7.2 Mindarie C (ML 6226) and Mindarie A(2) (6220) 107 7.2.1 Native vegetation 107 7.2.2 Weeds and pests 113 7.2.3 Noise and vibration 116 7.2.4 Traffic 120 7.2.5 Indigenous and non-Indigenous heritage 125 7.2.6 Community consultation and landuse management 128 7.2.7 Visual amenity and landscaping 132 7.2.8 Air quality 136 7.2.9 Radiation and asbestiform materials 140 7.2.10 Surface water and stormwater 142 7.2.11 Groundwater 146 7.2.12 Topsoil and subsoil 152
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Contents (Continued)
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7.3 Consolidated summary of environmental outcomes and measurement criteria 156
8. Mine Closure and Rehabilitation Plan 167 8.1 General 167 8.1.1 Stakeholder involvement and issues 167 8.1.2 Scope and review 167 8.1.3 Potential environmental, economic and social impacts of mine closure 168 8.1.4 Rehabilitation Mine Closure and Criteria Plan 169 8.1.5 Closure outcomes 170 8.1.6 Other conditions 170 8.2 Mindarie C (ML 6226) 171 8.2.1 Environmental baseline 171 8.2.2 Description of closure Domains 171 8.2.3 Summary of environmental outcomes and completion criteria 171 8.2.4 Compliance with other environmental conditions 175 8.2.5 Closure strategies for each Domain 176 8.2.6 Closure management 178 8.2.7 Post closure monitoring and management 182 8.2.8 Closure cost estimate/bond 183 8.3 Mindarie A(2) (ML 6220) 185 8.3.1 Environmental baseline 185 8.3.2 Status of current rehabilitation 185 8.3.3 Summary of environmental outcomes and completion criteria 185 8.3.4 Compliance with other environmental conditions 188 8.3.5 Closure management 189 8.3.6 Post closure monitoring and management 190 8.3.7 Closure cost estimate/bond 191 8.3.8 Mine closure schedule 193
9. Management systems and capability 195 9.1 Commitment and leadership 195 9.2 Policies and objectives 195 9.2.1 Environmental policy 195 9.2.2 Procedures and practices 196 9.3 Organisation, resources and documentation 196 9.3.1 Organisation structure and resources 196 9.3.2 Documentation 197 9.4 Risk evaluation and management 198 9.4.1 Job safety analysis 198 9.4.2 Contractor management 198 9.4.3 Management review 198 9.5 Planning 198
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Contents (Continued)
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9.6 Implementation, recording and monitoring 199 9.7 Audit and review 199 9.7.1 PEPR review and amendments 199 9.7.2 Annual Compliance Report 199 9.8 Previous experience of operator 200 9.9 Lease conditions 201
10. References 203
List of tables Page number
Table 2.1 Summary of operator and contact details 5 Table 2.2 Mining tenement and land ownership summary – Mindarie C strandline (ML6226) 6 Table 2.3 Mining tenement and land ownership summary – Mindarie A(2) strandline (ML6220) 6 Table 3.1 Other relevant Acts and policies 12 Table 4.1 Background noise measurements 19 Table 4.2 Noise Modelling Results 19 Table 4.3 Rainfall data 20 Table 4.4 Annual minimum and maximum temperatures 21 Table 4.5 Landscape zones and land unit characteristics of the proposed mine area 25 Table 4.6 Observed soil profile for Mindarie C and Mindarie A(2) 26 Table 4.7 Soil analysis results for Mindarie C and MindarieA(2) 26 Table 4.8 Metals in soil samples for Mindarie C and A(2) 26 Table 4.9 Calculated maximum salinity (ECSE) 27 Table 4.10 Plant salt-tolerance data 27 Table 4.11 Non indigenous heritage items, District Council of Karoonda East Murray Area 40 Table 5.1 Key characteristics of the Mindarie C project 44 Table 5.2 Mindarie C – maximum project clearance footprints 44 Table 5.3 Mindarie C project schedule 45 Table 5.4 Mindarie Mineral Sands Project ore reserve estimate (2008 figures updated based on a 60m x 25m drilling grid for Mindarie C East) 50 Table 5.5 Expected management of the waste streams generated by Mindarie C project 74 Table 5.6 Site mobile equipment 78 Table 5.7 Mobile equipment output information 79 Table 5.8 Operations workforce 79 Table 5.9 Estimated annual power consumption 80 Table 5.10 Rehabilitation strategy and schedule from mid 2011 to early 2012 83 Table 6.1 Preliminary stakeholder list 85 Table 6.2 Australian Zircon (AZ) stakeholder consultation tools 86 Table 6.3 Written submissions stakeholder list 88 Table 6.4 Mindarie C project Stakeholder Submissions 88 Table 6.5 Stakeholder activities and tools 90
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List of tables (Continued)
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Table 6.6 Landholder meetings – issues raised 91 Table 6.7 Community meeting tools 92 Table 6.8 Community issues and feedback integration 93 Table 6.9 Ongoing consultation communications and engagement tools and activities 94 Table 7.1 Schedule 2 Mining Lease Conditions and outcomes 100 Table 7.2 Environmental outcomes, risk levels, control and management strategies and measurement criteria – native vegetation 111 Table 7.3 Environmental outcomes, risk levels, control and management strategies and measurement criteria – weeds and pests 115 Table 7.4 Noise modelling results 116 Table 7.5 Environmental outcomes, risk levels, control and management strategies and measurement criteria – noise and vibration 119 Table 7.6 Environmental outcomes, risk levels, control and management strategies and measurement criteria – traffic 123 Table 7.7 Other environmental conditions and compliance assessment – visual amenity and landscaping 124 Table 7.8 Environmental outcomes, risk levels, control and management strategies and measurement criteria – indigenous and non-Indigenous heritage 127 Table 7.9 Environmental outcomes, risk levels, control and management strategies and measurement criteria – community consultation and landuse management 130 Table 7.10 Other environmental conditions and compliance assessment – community consultation and landuse management 131 Table 7.11 Other environmental conditions and compliance assessment – visual amenity and landscaping 135 Table 7.12 Environmental outcomes, risk levels, control and management strategies and measurement criteria – air quality 139 Table 7.13 Environmental outcomes, risk levels, control and management strategies and measurement criteria – radiation and asbestiform materials 141 Table 7.14 Environmental outcomes, risk levels, control and management strategies and measurement criteria – surface water 144 Table 7.15 Environmental outcomes, risk levels, control and management strategies and measurement criteria – groundwater 150 Table 7.16 Environmental outcomes, risk levels, control and management strategies and measurement criteria – topsoil and subsoil 154 Table 7.17 Outcomes and criteria 156 Table 8.1 Potential impacts after mine closure 168 Table 8.2 Proposed land use for each Domain on closure 171 Table 8.3 Mine closure and rehabilitation – outcomes and completion criteria Mindarie C 173 Table 8.4 Other environmental conditions and compliance criteria – mine closure and rehabilitation Mindarie C 175 Table 8.5 Closure strategies for closure of Domain 1 (conceptual) 176 Table 8.6 Closure strategies for closure of Domain 2 (conceptual) 177 Table 8.7 Closure strategies for closure of Domain 3 (conceptual) 177 Table 8.8 Schedule for closure and rehabilitation 179 Table 8.9 Management actions – rehabilitation and mine closure 179 Table 8.10 Monitoring activities and requirements – rehabilitation and mine closure 182 Table 8.11 Closure cost estimate 184
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List of tables (Continued)
Page number
Table 8.12 Mine closure and rehabilitation – outcomes and completion criteria Mindarie A(2) 186 Table 8.13 Other environmental conditions and compliance assessment – mine closure and rehabilitation Mindarie A(2) 188 Table 8.14 Management strategies – rehabilitation and mine closure 189 Table 8.15 Monitoring activities and requirements – rehabilitation and mine closure 190 Table 8.16 Closure cost estimate 192
List of figures Page number
Figure 4.4 Mean monthly rainfall for Mindarie SA (BOM 2011a) 21 Figure 4.6 Mindarie C strandline cross section 24 Figure 5.3 Typical cross section of mining operations 56 Figure 5.5 Tailings deposition 63 Figure 5.9 Water balance estimate 70 Figure 5.10 HMC stockpile drainage 73
List of photographs Page number
Photo 4.1 Mining of Mindarie A(2) strandline during 2008 17
Appendices
Appendix A Certificates of Title Appendix B Dust Monitoring Reports (July 2008–2009) Appendix C Noise Assessments Appendix D EBS Biodiversity Survey Appendix E Management Plans Appendix F Mining Lease Number 6226 Appendix G Mindarie C Environmental Risk Assessment Appendix H Environmental Policy Appendix I Community Consultation Plan Appendix J Guide to information location in the PEPR Appendix K Lease Conditions Appendix L Figures
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Acronyms
AARD Aboriginal Affairs and Reconciliation Division ABS Australian Bureau of Statistics AHD Australian Height Datum AZ Australian Zircon BDBSA Biological Database of South Australia BOM Bureau of Meteorology CFS Country Fire Service DCPT Dynamic Cone Penetration Tests DENR Department of Environment and Natural Resources DFW Department for Water DPTI Department of Planning Transport and Infrastructure DMITRE Department of Manufacturing, Innovation, Trade, Energy and Resources DTEI Department of Transport, Energy and Infrastructure EBS Environmental and Biodiversity Services EM Electromagnetic
EP Act Environment Protection Act 1993 EPA South Australian Environment Protection Authority
EPBC Act Environment Protection and Biodiversity Conservation Act 1999 EML Extractive Minerals Licence FOS Factors of Safety HMC Heavy Mineral Concentrate MARP Mining and Rehabilitation Program MCRP Mine Closure Rehabilitation Plan ML Mega litres MMCCC Murray Mallee Community Consultative Committee MPL Miscellaneous Purposes Licence MPWA Mallee Prescribed Wells Act MSP Mineral Separating Plant MZ Murray Zircon NES National Environmental Significance NGER National Greenhouse and Energy Register
NRM Act Natural Resources Management Act 2004 NV Act Native Vegetation Act 1991 NVC Native Vegetation Council
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NVMMP Native Vegetation Management and Monitoring Plan PIRSA Primary Industries and Resources South Australia PCP Primary Concentrator Plant PLC Programmable Logic Control PEPR Program for Environment Protection and Rehabilitation RMP Radiation Management Plan RMCCP Rehabilitation Mine Closure and Criteria Plan SCADA Supervisory Control and Data Acquisition SEB Significant Environmental Benefit SEWPAC Sustainability, Environment, Water, Population and Communities SWL Standing Water Levels TDS Total Dissolved Solids THM Total Heavy Mineral UPS Uninterruptible Power Supplies VMC Valuable Heavy Mineral
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1. Introduction
Murray Zircon Pty Ltd (MZ) is proposing to initiate operations of the Mindarie Mineral Sands Project by re-commencing mining of the Mindarie C strandline. The Mindarie Mineral Sands Project is located approximately 150 km east of Adelaide in the Murray Mallee Region of South Australia and involves the mining of eight mineral sands strandlines located in nine separate Mineral Leases and two Exploration Licences (refer Figure 1.1, Appendix L).
MZ proposes to commence mining operations on a portion of the remainder of the Mindarie C strandline from Section 27 in the west to Section 22 in the east in the first half of 2012 (refer Figure 1.1, Appendix L)).
The project will use open pit mining techniques to produce approximately 120,000 tonnes of Heavy Mineral Concentrate (HMC) per annum (tpa) over an initial mine life of two years. The HMC will be sold at mine gate and transported initially via road transport to Port Adelaide for shipment overseas where it will be further processed and sold. There is potential for the HMC to be transported via the railway to Port Adelaide in the future.
In addition, MZ will continue to rehabilitate the Mindarie A(2) strandline and return the rehabilitated land to the relevant landholders.
The development and operation of the project is expected to result in:
economic benefits such as expenditure during operation, royalty payments and salaries social benefits such as employment opportunities, training and education environmental benefits such as improved rehabilitation of areas of disturbance from previous mining activities.
In accordance with the Mining Lease for the Mindarie C strandline (ML6226) and the Mindarie A(2) strandline (ML6220), MZ have developed this Program for Environment Protection and Rehabilitation (PEPR) for approval by the Department of Manufacturing, Innovation, Trade, Energy and Resources (DMITRE).
Details about the proponent, MZ, are provided in Section 2 – Proponent details.
1.1 Project history
In 2004 Australian Zircon NL (AZ) received approval pursuant to the requirements of the Mining Act, 1971 to develop the Mindarie Zircon Project.
The nine mineral strandlines in the first mining plan were to be developed sequentially. Site establishment and construction activities for the first of the strandlines – Mindarie A(2) commenced in 2006. Following construction and commissioning of plant and equipment, mining of mineral sands in the A(2) strandline commenced in April 2007 at an initial design rate of 3.5 to 4 million tonnes per annum (Mtpa) of ore which would result in the production of some 140,000–180,000 tpa of HMC.
As required by Primary Industries and Resources South Australia (PIRSA) and Condition 2.1(a) of the Mindarie A(2) lease conditions (ML6220), AZ developed and submitted a Mining and Rehabilitation Program (MARP) for the Mindarie A(2) strandline prior to commencement of activities on the strandline. The MARP was approved by PIRSA in
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24 August 2006. As required by PIRSA and Condition 2 of the Mindarie C lease conditions (ML6226), AZ previously developed and submitted a MARP for the Mindarie C strandline prior to commencement of activities on the strandline. The MARP was approved by PIRSA on 27 July 2009.
AZ began mining operations on the Mindarie C strandline (refer Figure 1.2, Appendix L)) in July 2009 with mining activities commencing in a section of the strandline immediately west of Loxton - Murray Bridge Road (approximately 0.05 ha in size). In October 2009 mining activities ceased when AZ voluntarily appointed an Administrator.
In June 2011, a Joint Venture between Guangdong Orient Zirconic Sci and Tech Ind and Australian Zircon, known as Murray Zircon Pty Ltd (MZ), was formally established.
MZ proposes to commence mining operations on the remainder of the Mindarie C strandline (refer Figure 1.2, Appendix L) in the first quarter of 2012 with mining activities starting northwest of the Loxton – Murray Bridge Road moving towards the east. Once the western side of the strandline has been mined, the operations will move to the eastern side of the Loxton – Murray Bridge Road. The proposed mining method consists of a dry ‘mobile hole’ concept thereby allowing for the removal of approximately 3 million tonnes of ore per annum (tpa) over an initial mine life of two years and eight months. The extracted mineral sands will be mixed with water to form slurry with the slurry unit located in the mine pit or adjacent to the mine pit. The slurry will then be pumped to the Primary Concentrator Plant (PCP) where it is processed to form HMC and transported initially via road transport (or rail in the future) to Port Adelaide for export.
In addition MZ will continue to rehabilitate the Mindarie A(2) strandline and return the rehabilitated land to the relevant landholders.
1.2 Program for Environment Protection and Rehabilitation
1.2.1 Objectives and context
This Program for Environment Protection and Rehabilitation (PEPR) has been prepared by MZ in accordance with the requirements of the Mining Act 1971 and Mining Regulations 2011 (as amended on 1 July 2011) and demonstrates that the outcomes specified in lease conditions for ML6226 and ML 6220 can be achieved.
The PEPR also reflects changes in project design, footprint and feedback from key stakeholders (including DMITRE, landowners, community) during the preparation of this document.
The PEPR content is consistent with the requirements of the Draft Determination by the Minister for Mineral Resources Development, dated November 2011 and PIRSA MG1: Guidelines for Miners” Mining Approvals Processes in South Australia (version 1 February 2009) and MG2: Preparation of Mining Rehabilitation Program (MARP) in South Australia (version 4.11 January 2011).
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1.2.2 Structure and content of PEPR
The structure and content of this PEPR is as follows:
Section Content Section 1 Introduction – provides details on background, project history and report structure Section 2 Project proponent – provides details on MZ Section 3 Legislative requirements – summary of legislation requirements associated with the project Section 4 Existing environment – description of existing environment including physical, socio-economic and heritage aspects Section 5 Project description – detailed description of project operations and associated infrastructure Section 6 Stakeholder consultation – details of stakeholder consultation to date and future strategy Section 7 Environmental outcomes – details of each environmental aspect, identification of potential risks, description of proposed mitigation and management strategies, details on environmental outcomes and measurement criteria and proposed monitoring to be undertaken to demonstrate the achievement of environmental outcomes. Section 8 Mine closure and rehabilitation plan – details conceptual mine closure and rehabilitation plans for Mindarie C and Mindarie A(2) Section 9 Management systems and capability – details of MZ’s corporate management systems and reporting requirements Section 10 References Appendices
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2. Proponent details
2.1 Project proponent
The proponent of the Mindarie Mineral Sands Project is Murray Zircon Pty Ltd (MZ), a joint venture between Guangdong Orient Zirconic Sci and Tech Ind (Orient Zirconic) and Australian Zircon NL (AZ). MZ is listed on the Australian Stock Exchange and commodities that are of particular interest to the company include zircon.
AZ’s major business activities are mining and processing titanium minerals, mining and processing zircon and mineral exploration. Orient Zirconic is one of China’s largest zircon processing companies with its headquarters at Shantou in Guangdong Province. It is a large enterprise which specialises in the manufacture and research of zirconium products for ceramics, electronics, fibre connectors, aviation field, spaceflight and solid fuel batteries.
The contact details for this project are summarised in Table 2.1.
Table 2.1 Summary of operator and contact details
Name of operator Murray Zircon Pty Ltd ABN 75 147 048 744 Address of registered Level 6, West office 50 Grenfell Street Adelaide SA 5000 Address of office at PO Box 1657 project site Loxton SA 5333 Name of contact person Mr Eddy Wu CEO Telephone 08 8410 8884 Email [email protected]
2.2 Project location and mining tenements
The project is located approximately 150 km east of Adelaide in the Murray Mallee Region of South Australia and involves the mining of multiple mineral leases (refer Figure 1.1, Appendix L). The closest towns to the project are Mindarie located approximately 2.5 km south and Wanbi approximately 10 km north-east.
The Mindarie C strandline footprint and associated infrastructure are located on 1,938.35 ha which are covered by ML6226 and is defined in this report as the mineral lease area for Mindarie C. The Mindarie A(2) mining footprint is located on 639 ha which is covered by ML6220 and is defined in this report as the mineral lease area for Mindarie A(2). The operations on ML6226 entail the mining of the Mindarie C strandline (East, West and Far East) and are addressed by this PEPR. (refer Figure 1.2, Appendix L).
Details of the current tenure and land ownership of the Mindarie C strandline is included in Table 2.2. Copies of Certificate of Titles are contained in Appendix A.
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Table 2.2 Mining tenement and land ownership summary – Mindarie C strandline (ML6226)
Hundred Section Title number Land owner Chesson S23 CT5533/212 Zadow Farm Security Pty Ltd Chesson S45 CT5969/756 Zadow Farm Security Pty Ltd Chesson S44 CT5885/73 K. J. Heidrich and R. A. Heidrich Chesson S39 CT5369/401 A. T. Evans and A. G. Evans Chesson S41 CT5939/633 A. T. Evans , A. G. Evans and J. T. Evans Chesson S40 CT5878/80 G. U. Pfitzner Chesson S28/62/77 CT5995/537 A. T. Evans and A. G. Evans Chesson S29 CT5301/108 J. M. Curtis Chesson S30 CT5597/179 J. M. Curtis Chesson S27 CT5737/3 L. Curtis Chesson S26 CT5988/516 J. R. Tokin and R. J. Tonkin Chesson S37 CT5352/850 E. V. Francis Mindarie A1/S37 CT5945/521 E. V. Francis Mindarie S7 CT5945/523 I. R. Francis, E. V. Francis, and D. W. Francis Mindarie S32 CT5384/33 Wanbi Farm Holding Pty Ltd Mindarie S33/34 CT5893/315 P. J. Crouch and A. L. Crouch Mindarie S9/13/22/23 CT5937/218 S. T. Proud and B. C. Proud Mindarie S21/24 CT5964/977 P. J. Crouch and A. L. Crouch Mindarie A2 CT5945/522 Mallee Mineral Separations Pty Ltd NB: those landowners affected by operations on Mindarie C are highlighted.
Details of the current tenure and land ownership of the Mindarie A(2) strandline is included in Table 2.3. Copies of Certificate of Titles are contained in Appendix A.
Table 2.3 Mining tenement and land ownership summary – Mindarie A(2) strandline (ML6220)
Hundred Section Title Number Land owner Mindarie S7 CT5945/523 I. R. Francis, E. Victor, and D. Wayne Mindarie Pieces of 1 and 3 CT5945/521 E. V. Francis Deposited Plan 67236 Chesson S26 CT5988/516 J. R. Tokin and R. J. Tonkin Mindarie S34 CT5893/315 P. J. Crouch and A. L. Crouch
2.3 Local government
The project is located within the District Council of Karoonda East Murray in the central portion of the Murray Mallee Planning Region.
The area’s primary industries are broad-acre production of wheat and barley, breeding of sheep (predominantly Merino/Poll Merino) for their meat and wool. Secondary and tertiary industries include breeding of pigs, beef cattle, alpacas and the production of sorghum, oats, lupins, beans, olives, onions, potatoes, pumpkins, pomegranates and Paulownia trees (DCKEM 2011).
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3. Legislative requirements
3.1 South Australian legislation
In South Australia minerals are the property of the Crown and mining is governed by the following Acts and Regulations:
Mining Act 1971, and Mining Regulations 2011 Offshore Minerals Act 2000 Opal Mining Act 1995.
In addition to the above Acts and Regulations, there are a number of South Australian and Commonwealth Acts and regulatory processes that apply to the operational activities associated with mining projects. A description of the relevant Acts and the process by which MZ will meet necessary statutory requirements under these Acts is discussed in the following sections.
3.1.1 Mining Act 1971
Approval for the original AZ project was sought under the Mining Act 1971 which is administered by DMITRE.
3.1.1.1 Mineral lease
Construction and operation of a mine can only be undertaken with an approved Mineral Lease (ML) and all mineral leases require that the mining operation is carried out in an orderly and skilful manner in accordance with an approved PEPR and with an appropriate rehabilitation bond in place.
On 25 July 2006, AZ was granted ML6220 for the Mindarie A(2) deposit and commenced site establishment and construction activities in 2006. On 6 May 2009, AZ was granted ML6226 for the Mindarie C deposit and commenced mining operations on the strandline in July 2009 with mining commencing on a section of the strandline immediately west of the Loxton – Murray Bridge Road. In October 2009 mining activities ceased when AZ voluntarily appointed an Administrator. This PEPR covers the proposed MZ operations on the remainder of the Mindarie C strandline as detailed in Section 5 as well as the completion of rehabilitation works on the Mindarie A(2) strandline.
Following approval, this PEPR will become the key environmental management document for the Mindarie C operations and completion of rehabilitation of Mindarie A(2). A stamped, numbered copy of the PEPR will be kept on site at all times and as required by the provisions of the Mining Act 1971 and will be updated at intervals of no longer than every seven years.
Earlier review of the PEPR must be undertaken if directed by the Minister and may be required if:
any additional significant environmental risks are identified a lease renewal is required there is a change in the operation or operator the PEPR is not proving to be adequate in addressing environmental risks, and/or
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there is a change in community or stakeholder expectations regarding the operation that is considered significant enough for DMITRE to require an update.
3.1.1.2 Miscellaneous Purposes Licences (MPLs) and Extractive Mineral Leases (EMLs)
In August 2006, AZ applied for an Extractive Minerals Lease (EML) for a rubble pit (RP1) required as part of the mining project. PIRSA granted EML No. 6232 (over Mineral Claim) MC3649 on the 17 October 2006. The EML is for a term of seven years and commenced on 20 September 2006. A Native Vegetation Management Plan and Mining and Rehabilitation Program were developed to cover the activities associated with EML No. 6232.
Construction of infrastructure with a mining development (but not within the mineral lease area) requires a Miscellaneous Purposes Licence (MPL) (pursuant to the requirements of Part 8 of the Mining Act 1971). MPL 80 was granted by PIRSA on 25 of July 2006 to facilitate the construction and operation of the 66kV transmission line from the Material Separation Plant to the Pyap substation. The related Pyap to Mindarie Transmission Line Mining and Rehabilitation Program (MARP) detailing the project environmental requirements was submitted to PIRSA on 19 September 2006.
3.1.1.3 Exploration licences
The Mineral Leases and strandlines associated with the Mindarie Mineral Sands Project lie within three Exploration Licences (4016, 4017 and 4018). These licences expired on 1 January 2011 and are currently being renewed and transferred from AZ to MZ.
The Mindarie C and Mindarie A(2) MLs lies within the boundaries of Exploration Licences 4017 and 4018 (refer to Figure 1.1, Appendix L).
3.1.2 Natural Resources Management Act 2004
The Natural Resources Management Act 2004 (NRM Act) is administered by the Department for Water and promotes the sustainable and integrated management and protection of the State’s natural resources.
The abstraction and use of groundwater for the project will be governed by the NRM Act.
The NRM Act also provides for the creation of eight NRM regions within South Australia and the project lies within the South Australian Murray-Darling Basin NRM (SAMDB NRM) Board area.
3.1.2.1 Groundwater
The project area falls within the Mallee Prescribed Wells Area (MPWA) which is part of the Murray-Darling Basin. The Murray-Darling Basin is one of the State’s most productive agricultural regions. Groundwater is extracted from selected aquifers in the region and is particularly important in the Angas-Bremer plains and the Mallee regions for irrigation, stock and domestic uses.
Approval is required for abstraction and use of groundwater for the project and was previously granted by the Department for Water (previously known as Department for Water, Land, Biodiversity and Conservation) on 16 March 2007. The authorisation is for a period of ten years.
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The authorisation permits a maximum of 6,000 megalitres (ML) to be extracted from the Murray Group Limestone Aquifer per water use year and limits the total volume permitted to be extracted in the ten year period to 42,920 ML (providing an average of 4,292 ML per water year use).
The authorisation permits the use of the extracted water on the Mindarie C and A(2) strandlines (ML6226 and ML6220). The authorisation states that:
a maximum of 6,000 ML can be taken from the Murray Group Limestone Aquifer per water use year no more than 42,920 ML shall be taken from the Murray Group Limestone Aquifer over the 10 years of the authorisation the water use must not take water except through a meter, fitted to the satisfaction of the Minister for Environment and Conservation the water use must not cause, suffer or permit any interference with a meter used for the purposes of measuring the quantity of water used under the Notice or any interference with pipes or fittings that may affect the accuracy of a meter, without the Minister for Environment and Conservation’s authority the water user must not adjust or alter the meter without the Minister for Environment and Conservation’s authority the water user must not permit sand, soil or any other material to be deposited on or around a meter the water user must not permit deposits of sand, soil or any other material to build up around the meter the water user must keep vegetation cleared away from the meter the water user must not damage or destroy the meter the water use must comply with the terms and conditions, as authorised under the Mining Act 1971, of Mineral Leases 6137, 6219, 6220, 6221, 6222¸ 6223, 6225 and 6226.
3.1.2.2 Surface water
Surface water in the project area is not prescribed, however, permits under the NRM Act are required for ‘water affecting activities’ including activities that can have an impact on water resources and the ecosystems dependent on water. This includes activities such as excavation of rock, sand or soil from a watercourse, lake, floodplain or near the banks of a watercourse. It is not expected that any surface water affecting activities will be undertaken as part of the project.
3.1.3 Environment Protection Act 1993
The Environment Protection Act 1993 (EP Act) provides for the protection of the environment. This Act is administered by the South Australian Environment Protection Authority (EPA).
3.1.3.1 General environmental duty
In addition to the various lease conditions that have been applied to the project area, MZ also has a ‘general environmental duty’ under the EP Act.
This general duty (as detailed in Section 25, Part 4 of the EP Act) specifies that a person must not undertake an activity that pollutes, or might pollute, the environment unless the
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person takes all reasonable and practicable measures to prevent or minimise any resulting environmental harm.
In determining what measures are required to be taken, consideration must be given to:
the nature of the pollution or potential pollution, and the sensitivity of the receiving environment the financial implications of the various measures that might be taken as those implications relate to the class of persons undertaking activities of the same or a similar kind the current state of technical knowledge and likelihood of successful application of the various measures that might be taken.
3.1.3.2 Environmental authorisations
Approvals are required for any activity associated with the project which is classified as a prescribed activity of environmental significance under Schedule 1 of the EP Act. Approvals for prescribed activities under the EP Act are in the form of a works approval and/or licence from the EPA.
Operations to be undertaken by MZ that are considered to be an ‘activity of environmental significance’ are:
Concentration of ore on site: a prescribed activity as described in Schedule 1(2)(9) of the Act as ‘Mineral Works – the conduct of works for processing mineral ores, sands or earths to produce mineral concentrates’.
Storage of diesel fuel: a prescribed activity as described in Schedule 1 (1)(5)(a) of the EP Act as ‘Petroleum Production, Storage and Processing Works or Facilities’ at which petroleum products are stored in tanks with a total storage capacity exceeding 2,000 cubic metres.’
A Works Approval was previously granted for the Mindarie Mineral Sands Project by the EPA in July 2006 for the construction of the Primary Concentrator Plant (PCP) and the Mineral Separating Plant (MSP) which are respectively located on and adjacent to Mindarie A(2) (ML6220).
In March 2007 the EPA granted EPA Licence 16862 for the concentration of ore on site with the licence covering the operation of the PCP, MSP and the Concentrate Upgrade Plant (CUP).
At present MZ stores 5,000 litres of diesel fuel on site and has approval from the EPA to store 190,000 litres of diesel fuel on site. Should the project require more storage of diesel fuel on site, an application will be submitted to the EPA and storage areas will be developed which meet the requirements outlined in the EPA’s Bunding and Spill Management Guidelines 2007.
As part of preparing this PEPR, the EPA provided advice to MZ in September 2011 regarding the transportation of HMC to Port Adelaide. The EPA advice indicated that the total activity of the HMC will be low enough to be exempt from the requirements of the Australian Code of Practice for the Safe Transport of Radioactive Material 2008 which is the primary document brought into force by the Radiation Protection and Control (Transport of Radioactive Substances) Regulation 2003.
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3.1.4 Development Act 1993
The Development Act 1993 provides land use approval for the life of the operations of a development and until such time that another application is approved to change or amend the standing approvals.
Development must be approved under Section 23 of the Act with the definition of development provided under Section 4 (1) of the Act. The construction of the MSP, borrow pit and accommodation village previously obtained development approval under the Act.
The Development Application for the accommodation camp and for the Mindarie MSP was lodged with the District Council of Karoonda East Murray in 2005. Development Approval was granted by Council on the 11 October 2006 and provisional Building Rules consent was given on the 16 October 2006. The Development Approval and Building Rules Consent were granted with a number of provisions. The construction camp has since been dismantled and decommissioned.
A new workers accommodation camp may be required for the re-commencement of mining of the Mindarie C strandline. The proposed location of the accommodation camp will likely be within the Wanbi Township and development of the camp will be the Contractor’s responsibility. Additionally MZ may also require the redevelopment of some existing houses within private property located in close proximity to the Mindarie Mineral Sands Project area.
MZ are in discussions with the Council to determine what approvals are required for the workers accommodation camp and/or redevelopment of existing housing.
3.1.5 Native Vegetation Act 1991
The Native Vegetation Act 1991 (NV Act) regulates the clearance and management of native vegetation throughout South Australia. It also ensures that areas of high conservation value are protected and that minor vegetation clearance is subject to a thorough assessment process.
For mining projects, DMITRE currently has been delegated authority by the Native Vegetation Council for the administration of the NV Act. As part of the mining approvals, a PEPR must include a Native Vegetation Management Plan (NVMP) which is assessed against the requirements of the NV Act.
The NVMP and consideration of Significant Environmental Benefit (SEB) for the project is included in Appendix E.
3.1.6 National Parks and Wildlife Act 1972
The National Parks and Wildlife Act 1972 provides for the establishment and management of reserves for public benefit and enjoyment, the conservation of wildlife in a natural environment and for other purposes.
The Act was designed to allow for the establishment and maintenance of a system of reserves as well as the protection of threatened species of flora and fauna. It identifies and protects certain species located within parks and reserves, as well as any species listed under Schedules 7, 8 and 9 of the Act.
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Section 34 of the Act allows for the constitution of Regional Reserves which allow for the conservation of wildlife and natural features while at the same time permitting use of natural resources of the land. Mineral exploration and mining are allowed subject to controls consistent with the Act and, where developed, the Reserve Management Plan.
Seed collection permits are required to collect seeds for rehabilitation and completion purposes. Ethics approval and associated permits are required for any further fauna survey activities. These approvals are generally obtained by the sub-consultant undertaking the work.
3.1.7 Other relevant State legislation
There are a number of other South Australian Acts and policies that are, or may be, relevant to the project.
Details of these Acts and policies are provided in Table 3.1.
Table 3.1 Other relevant Acts and policies
Act/policy Objective/ Relevant section(s) How it applies to the purpose project Aboriginal Heritage To provide for the Authorisation under If an Aboriginal site is Act 1988 protection and Section 23 must be found or needs to be preservation of obtained before disturbing disturbed during the Aboriginal sites, a known Aboriginal site. project, MZ will be objects and human Section 12 provides a required to consult with remains (including process for determining if traditional owners. burials). a site or object is an An Access Clearance Aboriginal site or object. Survey was conducted in Section 20 controls the 2006. discovery and search for Aboriginal objects and remains. Native Title (South To outline the Section 39 – confirms Relates to the negotiation Australian) Act existence of native Crown ownership of all of native title rights over 1994 title, native title natural resources within vacant Crown land. rights, South Australia. Section Under the provisions of compensation for 43 also establishes the Act MZ is required to extinguishment or alternative right to negotiate (and have impairment of negotiate provisions for agreements in place) prior native title and mining activity through to commencement of acquisition of amendments to the SA mining operations. native title in land, Mining Act 1971. or entry to/ Native Title Agreements occupation of for the project are in place. native title land or any other matter related to native title. Heritage Places To provide for the Section 16 provides the If a non-Aboriginal Act 1993 identification, criteria of what is heritage site is found or recording and considered to be of needs to be disturbed conservation of heritage significance. The during the project, MZ will places and proposal to make entry be required to consult with objectives of non- into the South Australian the South Australian Aboriginal heritage heritage register is Heritage Council. significance. provided in Section 17.
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Act/policy Objective/ Relevant section(s) How it applies to the purpose project Mines and Works To improve the Schedule 5 – The Act allows for the Inspection Act regulation and Responsibilities and duties inspection of the Mindarie 1920 inspection of of owners and persons C mining project works (by mines and employed within mines DMITRE) throughout the associated works. and associated works life of the project. Country Fires Act Provides for the Various provisions Prohibits (subject to 1989 prevention, control including: subsection provisions) the and suppression of Section 36(1) lighting of fires in the open fires; to provide for air during fire danger the protection of Section 39(1) season. life and property in The Country Fire Service fire and other (CFS) can direct MZ to emergencies. extinguish or manage a fire or may undertake extinguishment/managem ent of a fire themselves. Occupational To secure the Part 3 – General MZ is required to comply Health Safety and health, safety and Provisions related to with all aspects of the Act Welfare Act 1986 welfare of persons occupational health, safety relating to occupational at work; to protect and welfare. health, safety and welfare. the public against risks to health or safety arising out of, or in connection with, the activities of persons at work or the use or operation of various types of machinery. Pastoral Land To make provision Section 22 – Lessee’s Under the provisions of Management and for the obligation to comply with the Act Pastoral Lessees Conservation Act management and SA Natural Resource are obliged not to hinder 1989 conservation of Management Act 2004 & or obstruct any person pastoral land; and SA Mining Act 1971 and who is exercising, or for other purposes. any regulations under attempting to exercise, a those Acts. right of access to the land pursuant to this Act or any other Act Climate Change Provides for N/A Various requirements and Greenhouse measures to assist relating to State targets to Emissions in the achievement address climate change. Reduction Act of ecologically MZ incorporated suitable 2007 sustainable planning to minimise fuel development in the use. State by addressing issues associated with climate change; to promote commitment to action within the State to address climate change.
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Act/policy Objective/ Relevant section(s) How it applies to the purpose project Radiation To provide for the Section 29 – Registration Certificates #19307 (CUP Protection and control of activities of premises in which and MSP) and #19308 Control Act 1982 related to unsealed radioactive (mining pit and PCP) were radioactivity substances are handled or issued to AZ on 24 May substances and kept. 2006. apparatus, to The EPA has previously protect the confirmed that the environment and registration of Mindarie C the health and mine pit can be safety of people incorporated in to the against the harmful current registration. effect of radiation Environment No specific N/A Ground level nitrogen Protection (Air objective is dioxide from the diesel Quality) Policy established for the motor exhaust (from all 1994 policy. generators) conforms to the limits as outlined in the policy. MZ will take reasonable measures to maintain fuel- burning equipment (generators) to: . be used in an efficient condition . operate in a proper and efficient manner . carry out maintenance; and . process, handle, move or store goods or materials in or on the premises in a proper and efficient manner. Environment Set procedures for Parts 4 – 7 MZ (as the occupier) of Protection (Noise) measuring noise to non-domestic premises Policy 2007 determine must not cause or permit compliance with excessive noise to be the Environment emitted from the Mindarie Protection Act C or A(2) project sites. 1993 and Noise Excessive noise is noise Policy. that exceeds the Set noise goals for background noise level at noise sources. a measurement site (off- Set out criteria for site sensitive receiver) and determining what exceeds the maximum requirements (if noise level for that time of any) regulators will day and the area (rural) in impose to deal which the project site is with noise sources located. not complying with Provides guidance on the policy. instrumentation Provided basis for requirements as well as a consistent time and place of noise approach relating measurements to noise in procedures and records. determination of project applications.
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3.2 Australian government legislation
3.2.1 Environment Protection and Biodiversity Conservation Act 1999
Under the provisions of the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) a referral of a proposal to the Commonwealth Environment Minister is required for actions that may have a significant impact on matters of national environmental significance (NES).
The EPBC Act identifies eight matters of NES:
World heritage properties National heritage places Wetlands of international importance (Ramsar wetlands) Listed threatened species and ecological communities Migratory species Commonwealth marine areas The Great Barrier Reef Marine Park Nuclear actions (including uranium mining).
The EPBC referral is necessary to determine whether a project requires assessment and approval under the Act. When a project is referred under the EPBC Act, the Commonwealth Department of Sustainability, Environment, Water, Population and Communities (SEWPAC) makes a determination regarding the status of the proposal as a Controlled Action (i.e. requiring approval) or Not a Controlled Action.
Based on the outcomes of the previous flora and fauna surveys undertaken for the project, a referral pursuant to the requirements of the EPBC Act has not been submitted.
3.2.2 Other relevant Commonwealth legislation
Other Commonwealth legislation relevant to the project includes the following acts (and associated amendments and regulations):
Aboriginal and Torres Strait Islander Heritage Protection Act 1984. Australian Heritage Council Act 2003. Australian Heritage Council (Consequential and Transitional Provisions) Act 2003. Dangerous Goods Amendment Act 2000. Environment and Heritage Legislation Amendment Act 2003. Heritage Act 1975.
3.3 National policies and strategies
The following national policies have been considered in the course of preparing this PEPR:
Intergovernmental Agreement on the Environment (1990). National Strategy for Ecologically Sustainable Development (1992). National Strategy for the Conservation of Australia’s Biological Diversity (1996). National Greenhouse Strategy (1998). National Environment Protection Measures. Ambient Air Quality (2003) Assessment of Site Contamination (1999)
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4. Existing environment
The area surrounding the Mindarie C strandline has undergone mine development activities commencing in 2006 by AZ. As part of the development of the Mindarie project, a mineral separation plant (MSP) and a Primary Concentration Plant (PCP) were constructed on land owned by AZ located between the Mindarie A(2) and C strandlines.
Mining of the Mindarie A(2) strandline commenced in April 2007 and in July 2009 mining moved to the Mindarie C strandline. Mining at Mindarie C ceased in October 2009 when AZ entered voluntary administration. Rehabilitation of the Mindarie A(2) and previously mined portion of Mindarie C strandlines has commenced. At the date of this submission of this PEPR approximately 95% of the previously mined sites have been successfully rehabilitated to a state similar to the surrounding agricultural land (refer to Section 4.12).
The aerial photo shown in Photo 4.1 was taken during the Mindarie A(2) mining activities and provides an illustration of the mineral sands mining operation.
Photo 4.1 Mining of Mindarie A(2) strandline during 2008
4.1 Land use and proximity to housing and infrastructure
The dominant land use of the project area is dryland agriculture, mostly as cropping and grazing. Wheat and barley are the main crops with lesser areas of rye, oats, triticale (a wheat/rye hybrid) and lupins.
The land has mostly been cleared of native mallee vegetation. Occasional areas of remnant, degraded, or regrowth vegetation and low density scattered trees exist within paddocks androadside vegetation. Remnant vegetation remaining in the relevant Hundreds range from 6% (Chesson) to 22% (McPherson). The hundred of Mindarie has approximately 11% remnant vegetation (Foulkes and Gillen 2000).
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The combined population of the townships of Mindarie and Halidon, located approximately 2.5 km and 8 km south of the MZ project site offices (respectively) is 28.
There are five residential properties in the vicinity of the Mindarie C strandline, however only three of these are within vicinity of planned activities. These are located between 150 m to 1,800 m from the mining activities on Mindarie C (refer to Figure 4.1, Appendix L).
The mining path also crosses Knights Well Road, a secondary road maintained by the District Council of Karoonda East Murray. The East Murray Area School is located 1.1 km to the north of the Mindarie C strandline. The school has approximately 40 students from Reception to Year 12.
4.2 Noise, dust and air quality
4.2.1 Air quality
Existing emissions to air are primarily related to dust generated from farming operations (harvesting and cultivation) vehicle movements along the unsealed road network and vehicle exhaust emissions. Periods of high wind are likely to exacerbate dust generation and lead to an increase in the concentration of airborne dust.
Environmental dust monitoring has been undertaken at the project area since December 2006. The annual radiation report prepared by On Site Technology Pty Ltd provides the results of the dust monitoring over the operational period between July 2008 and February 2011 (refer to Appendix B). Figure 4.2 (Appendix L) shows the locations of the upwind and downwind monitoring locations along the Mindarie A(2) strandline located adjacent to the Mindarie C strandline. Results are presented for the following:
positional monitoring of in plant inhalable dust Microvol dust sampling of up wind and downwind environmental samples high volume dust samples collected adjacent to the gas storage cylinder.
Dust deposition results showed elevated levels at some locations east of the Loxton – Murray Bridge Road since mining and overburden removal commenced in early November 2008 (Australian Zircon 2010). However, these higher yielding samples were restricted to those locations close to mining operations with limited impact at remote sites to the south and west of mining operations. Some elevated dust levels occurred to the west of the mining activities which could be attributed to earthworks associated with rehabilitation and grading of the mined areas (Australian Zircon 2010).
During the previous operational period of the mine only one air quality complaint was made by the public in regard to the presence of dust along McCabe Road. This issue was addressed by AZ reducing the speed limit for AZ employees and contractors along this road to reduce dust emissions.
4.2.2 Noise
The ambient noise in the vicinity of the mining operation is controlled by natural sounds such as wind and birds. At times when there is no wind at night, very low background noise levels have been recorded.
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A preliminary investigation of the background noise levels in the project area was conducted in February 2001 and during excavation of the trial pit.
A summary of the recorded background noise levels is presented in Table 4.1. Measurements of noise levels during the excavation of the trial open pit indicated average noise levels (when measured 15 m from the operations) of 76 dB(A) when the largest D10 dozer was in the excavation (8 to 10 m below surface) to 93 dB(A) near the surface.
The acoustic survey indicates that the background noise levels are in the order of 23 (early morning) and 25 dB(A) during the day at the residences.
Table 4.1 Background noise measurements
Measurement point Background Ambient (LA50) Ambient (LAeq) (LA90) (dB(A)) (dB(A)) (dB(A)) Residence 100 m from mining, 22.7 28.2 35.0 6 am-6:15 am As above 24.7 28.9 37.6 10 am to 10:15 am
Noise impacts from mining activities will depend on the distance from the houses to the mine. The mobile nature of the mine (moves about 20 m/day at the initial mining rate) will ensure that any adverse impacts, even for houses near the mine, will be short-lived.
Rehabilitation works are currently being undertaken within the Mindarie A(2) and Mindarie C strandlines where mining activities were completed by AZ. Noise associated with these rehabilitation activities include the use of four bulldozers including two D10, one D8 and one D7 bulldozers. Rehabilitation works occur six days a week and during the day only.
A noise assessment related to the Mindarie C deposit was conducted by Sonus in October 2011. A copy of this report is provided in Appendix C. The assessment focused on the noise levels expected from the mining operation at the closest dwellings and the school (refer to Figure 4.3, Appendix L). The noise assessment modelled the potential noise emissions associated with mining operations in comparison with the noise emission limits outlined in the South Australian EPA’s Environmental Protection (Noise) Policy 2007 and included a 5dB(A) penalty. The results of the noise assessment are outlined in Table 4.2 below.
Table 4.2 Noise Modelling Results
Site Modelled Noise Output dB(A) Noise Emission Limit (night time) dB(A) A 50 45 B 45 45 C 44 45
Whilst mining is not currently occurring within the project area it is expected that upon re- commencement of mining of the Mindarie C strandline the noise emissions would be as predicted in the Sonus 2011 noise report. Residence (A) is located in an area of the strandline that will not be mined due to the grade and resources of mineral sand. If in the future a decision is made to mine in this area MZ would implement the noise attenuation
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measures recommended by Sonus (establishment of a mound with a minimum height of 6m) to ensure that the night time noise limit will be met.
It should be noted that the noise assessment undertaken by Sonus assumed that noise generating activities would be located at the closest point to the dwellings with worst case (highest noise levels) weather conditions. At other times the noise levels would be significantly lower. The 10pm to 7am criterion of 45 dB(A) was exceeded (50 dB(A)) at dwelling “A”, a residence that is currently not occupied.
4.3 Topography and landscape
The project area is situated in the Murray Basin, which is bounded to the west by the Mount Lofty Ranges and southern Flinders Ranges and to the north by the Darling Basin. To the south-east, the Lachlan Fold Belt and the Victorian Highlands form the boundaries for the region.
The views within the Karoonda region are mainly middle ground panoramas, in which loose dune crests and mallee remnants form local features. Locally, the mallee region verges create perspective views along roads (Government of South Australia 2007).
The regional land surface consists of gently undulating plains with broad flats. This relief reflects the old strand-plain surface, which forms an accurate pattern of ridges and swales. The height of the land surface varying from approximately 50 m Australian Height Datum (AHD) to a maximum of approximately 80 mAHD with most of the ground surface lying below 65 mAHD.
4.4 Climate
The project is located in the Murray Mallee Region. The closest Bureau of Meteorology (BOM) site for which information is available for the project area is located at Mindarie, approximately 2.5 km south of the MZ project site offices.
4.4.1 Rainfall, humidity, evaporation and wind
The regional rainfall average is 300 mm, hence the site is considered a dry rural environment. The majority of rain falls in the winter growing season (April to October) which on average is 204 mm, with the lowest rainfalls over the summer months (December to March) averaging 53 mm. The mean annual rainfall for towns within the project area is indicated below Table 4.3). According to data from the BOM (2011a) July and August are the wettest months with average monthly rainfall of 31.1 mm and 33.4 mm. The driest months are January and February with 17.2 mm and 19.1 mm respectively.
Table 4.3 Rainfall data
Location Mean annual rainfall (mm) Alawoona 290 Sandalwood 327 Karoonda 339 Source: BOM 2011a
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Figure 4.4 below indicates the mean monthly rainfall for the project area.
Mean Monthly Rainfall for Mindarie SA 40
35
30
Rainfall… 25
20
15
10
5
0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Figure 4.4 Mean monthly rainfall for Mindarie SA (BOM 2011a)
Relative humidity is highest in June and July (approximately 85%) and decreasing in the summer months. Average annual pan evaporation for the area is estimated to be between 1,600 and 1,700 mm/annum (BOM 2006). At the nearest BOM recording location to Mindarie (Wanbi) the predominant wind direction is from the southwest at an average wind speed of 14 km/hour.
4.4.2 Temperature
The project area experiences temperatures ranging from 14.4°C (June) to 33.2°C in February, with an annual average temperature of 23.5°C. Mean daily minimum and maximum temperatures are tabled below (Table 4.4).
Table 4.4 Annual minimum and maximum temperatures
Month Mean maximum Mean minimum temperature (°C) temperature (°C) January 33.0 27.3 February 33.2 27.9 March 31.4 25.7 April 26.6 20.4 May 20.6 16.9 June 17.0 14.4
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Month Mean maximum Mean minimum temperature (°C) temperature (°C) July 17.1 14.9 August 19.1 15.0 September 22.2 16.4 October 25.6 20.0 November 31.5 25.5 December 30.6 26.4 Annual 24.3 20.9 Souce of Data: BOM, Karoonda Station (BOM 2011b)
4.5 Geohazards
The Mindarie area is of low seismic activity. Due to the nature of the proposed mining no specific earthquake allowance has been made (Brown and Stephenson, 1991).
The orebody contains low levels of naturally occurring radionuclides of the thorium and uranium decay chains. Although the ore is not considered radioactive under the current Australian definitions, in common with all mineral sands mining a Radiation Management Plan was prepared for the previous operations and submitted to the Radiation Protection Branch of the Environment Protection Authority for approval.
Occupational radiation monitoring was conducted at the Mindarie Mineral Sands Project site in 2009. Results of this monitoring event include (Waters 2009):
Dust inhalation was potentially the main source of occupational exposure in all areas of the site.
Occupational exposure to ionizing radiation was less than the regulatory limit of 20 mSv/year for all workers at the site. The maximum estimated dose (measured external plus calculated internal) was 10 mSv/year.
Average occupational exposure was approximately 3.6 mSv/year in the dry plant, 1.3 mSv/year in other plant areas and 0.26 mSv/year in non-plant areas of the site.
Environmental radiation monitoring was also conducted at the Mindarie Mineral Sands Project site in 2009. Results of this monitoring event include (Waters 2009):
There were no measurable radiological impacts on groundwater during the period July 2008 to June 2009.
Pre operational soil surveys indicated that background levels of uranium and thorium are low and that background gamma radiation dose rates are low.
Environmental dust and airborne radioactivity (as measured by alpha activity) were low and appeared to be primarily influenced by regional conditions rather than mining or processing operations.
Environmental radon and radon daughter levels were low and considered consistent with typical outdoor levels in rural inland Australia.
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4.6 Geology and soils
4.6.1 Regional geology
The Murray Basin succession is divided into three Tertiary age depositional sequences, overlain by a thin cover of Quaternary sediments. The Murray Basin covers an area of approximately 300,000 km2 and comprises Cainozoic marine and terrestrial sediments that were deposited in a low relief, saucer-shaped intracratonic basin (Brown and Stephenson 1991).
Sedimentation began in the Murray Basin in the Palaeocene with the deposition of a non- marine dominated succession, the Renmark Group. A minor marine incursion occurred in western and south-western areas, with deposition of the terrestrial component continuing into the middle Miocene. The second phase consisted mainly of marine sedimentary deposition, comprising clays and limestones of the Murray Group. The third episode of deposition consisted of a marine transgression which began with the laying down of a succession of plastic green, grey and brown calcareous clays and silts, with minor sand, named the Bookpurnong Beds. The Bookpurnong Beds are conformably overlain by a succession of marginal marine sands, known as the Loxton-Parilla Sands.
A large number of strandlines have been preserved within the Loxton-Parilla Sands throughout the Murray Basin, many of which, including the Mindarie heavy mineral sands deposits, contain significant concentrations of heavy minerals.
The Murray Basin is bounded to the southwest by basement rocks of the Mount Lofty and southern Flinders Ranges and to the north by late Palaeozoic rocks of the Darling Basin. Sedimentary and metamorphic rocks of the Lachlan Fold Belt and the Victorian Highlands form the eastern and south-eastern boundaries.
The Loxton-Parilla Sands is comprised of the following lithotypes:
micaceous clays silts silty sands cross-bedded micaceous sands with minor sandy conglomerate and pebble conglomerate, and fine to coarse grained sands
The Loxton-Parilla Sand unit is disconformably overlain by a sequence of non-marine late Pliocene to Recent sediments. This disconformity between these units is commonly marked by a ferruginous, locally siliceous, weathering profile known as the Karoonda Land Surface.
In the central sector of the basin, the overlying sediments are the fluvio-lacustrine green and red brown clays of the Blanchetown Clay, which range in age from 2.4 to 0.7 million years. In the Karoonda district, the Blanchetown Clay is generally absent or at best poorly developed.
Where the Blanchetown Clay is absent, the Loxton Sand is disconformably overlain by a thin succession of unconsolidated red-brown siliceous silty sand, sandy clay and clay-pellet aggregates, which forms extensive east-west oriented dunes of the Woorinen Formation. This unit varies in thickness from zero to approximately 30 m in locally developed dune fields.
The disconformity is also locally marked by the pedological development of calcrete (refer Figure 4.5, Appendix L). The calcrete, which locally forms massive sheets, is known as the
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Bakara Formation or the Ripon Calcrete. Where present it sits disconformably above the Loxton-Parilla Sand and the Blanchetown Clays and underlies, or is intercalated with, the Woorinen Formation.
The final unit is the development of late stage cresent shaped dunes known as the Lowan Sands. These sands are white to light brown and form high dune systems which generally preclude the exploration for mineral sands because of the increased overburden thickness and also because the Lowan Sand is nutrient deficient and has therefore never been cleared for agriculture resulting in it containing the majority of the high value vegetation conservation areas.
4.6.2 Local geology
The Mindarie heavy mineral sands deposits are located in the lower south western corner of the Murray Basin. In this area, the heavily mineralised Loxton-Parilla sands are often exposed at surface or thinly covered by low dunes interpreted to be of Woorinen Formation or isolated Lowan Sand dunes. From the surface, the general stratigraphic variation is unconsolidated fine to medium sands with occasional layers of sandy clay, clayey sand or clay in the top 0 to 5 m. Calcrete is also seen in the upper 0 to 5 m, usually with the clay units immediately underlying. Within the ore zone, sands are usually fine to medium, with a basal layer of very coarse to granular and occasionally pebbly sands usually up to 5 m thick.
Within the Mindarie Mineral Sands Project area, drilling has identified a series of shorelines containing strandline mineralisation of variable grade and mineral content, of which the Mindarie C deposit is a part. Figure 4.6 below depicts a typical geological cross section of the Mindarie C strandline.
Figure 4.6 Mindarie C strandline cross section
4.6.3 Soil
The soils of the area are generally well-draining sands to loamy sands with a low water- holding capacity, and are typically alkaline exhibiting increasing pH with depth. The soils are further characterised by low organic matter contents, low fertility and low cation exchange
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capacity. In general, these soils may be deficient in phosphorous, nitrogen, copper and zinc. The light sandy surface soils of the area are susceptible to wind erosion, particularly after tillage.
Figure 4.7 (Appendix L) shows the locations of the soil groups surrounding the Mindarie C and Mindarie A(2) strandlines as well as sampling locations. There are five soil groups which are listed below:
calcareous loam shallow calcareous loam on calcrete gradational sandy loam with highly calcareous lower subsoil deep carbonate sand deep bleached siliceous sand.
In addition, descriptions of the landscape zones and land unit characteristics relevant to the Mindarie Minerals Sands project are summarised below (refer Table 4.5)
Table 4.5 Landscape zones and land unit characteristics of the proposed mine area
Land units Comments Murbko, Kekwick, Note: This zone covers areas in both the southern and northern Mallee. As the Quirke, Billiatt, Mt proposed mining area falls within the northern part of this zone, only the Rescue, Peake, northern characteristics are reported here. Ngarkat . 65% low to moderate rounded and irregularly shaped sandhills up to 3 to Land Zone 4 9 m high. Soils consist of up to 0.10 m of lime-free sand of pH 9.0. . 25% large, steep sandhills, either jumbled or crescent shaped, of between 6 and 30 m high. Soils consist of up to 1.5 m coarse, reddish sand which is lime free in the top 0.4 m with a pH of 7.5 at the surface . 10% flat, small dish shaped areas between dunes. Soils usually consist of less than 0.3 m of loamy sand to sandy loan with a surface pH of 9, overlying lime rubble and calcrete. Wanbi, Halidon, . 35% low, rounded, parallel sandhills up to 9 m high. Usually at least 1.0 m Mindarie of lime-free sand, with a surface pH of 8.5 overlying subsoils with a slight Land Zone 5 accumulation of lime and clay . 5% jumbled sandhills of up to 9 to 15 m high. Sandy surface soils of pH 7.0 overlying a layer with an accumulation of lime and clay which may be exposed in eroded areas . 25% loamy flats with 0 to 0.3 m of lime loamy sand to sandy loam overlying sandy clay loam subsoil. The pH is typically 8.5 to 9 at the surface. . 30% sandy flats with variable depth to clay or calcrete. Generally 0.25 to 0.6 m of lime-free sand to loamy sand with a surface pH of 7.0 over sandy clay and fractured calcrete. . 5% stony rises with 0.05 to 0.3 m of lime free loamy sand to sandy loam with a surface pH of 8.5 to 9 over calcrete and lime rubble. The main variable is the depth to calcrete. Note: Soil background information was sourced from the Murray Mallee District Plan (1992) compiled by the Murray Mallee District Soil Board and in McCord (1995).
The initial assessment of the soil landscapes for the project area was based on the description of topography and soils of the agricultural districts of South Australia compiled by the PIRSA Land Resources Unit. Mapping of soil landscape units has been undertaken at a scale of 1:100,000 across the project area based on existing aerial photography, geology and soil maps and limited traverses. Soil landscape units describe distinct topographic
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features formed on particular geological materials and include a defined range of soil classes.
A preliminary soil survey was undertaken in 2002 and included the collection of soil samples from five locations across the Mindarie Mineral Sands Project mining area including two locations within the Mindarie C ML and 3 within Mindarie A(2) ML (refer Figure 4.7, Appendix L).
The soil profiles observed during the survey are described in Table 4.6 and results presented in Tables 4.7 and 4.8.
Table 4.6 Observed soil profile for Mindarie C and Mindarie A(2)
Site Sample Sample Soil landscape Comments ID depth (m) unit Min C 1A 0-0.33 Dune/swale systems Light orange, unconsolidated sand with with mainly neutral small amount of particulate organic matter to alkaline, 1B 0.33-0.45 Pale orange unconsolidated sand with unbleached siliceous particulate carbonate sand with calcareous subsoil on dunes Min A(2) 3A 0-0.20 Rises and plains Orange-brown unconsolidated sand with with mainly loamy particulate organic matter texture contrast or 3B 0.20-0.35 Generally as above for 3A gradational soil 3C 0.35-0.50 Orange-red fine textured loamy sand
Table 4.7 Soil analysis results for Mindarie C and MindarieA(2)
Sample pH EC (mS/cm) Sodicity Carbonate Sulfide Moisture Carbon (%) number (%) (%) (%) content (%) 1A (Min C) 6.1 21 0.15 0.55 <0.05 1 0.22 1B (Min C) 8.3 240 3.7 8.9 <0.05 7 1.88 3A (A(2)) 6.5 68 2.15 1.15 <0.05 2 0.34 3C (A(2)) 6.8 200 0.3 2.85 <0.05 3 0.94
Table 4.8 Metals in soil samples for Mindarie C and A(2)
Sample As B Be Cd Cr Cu Mo Ni Pb Sb Se Sn Zn number ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm 1A (Min C) blr blr blr blr blr blr blr blr blr blr blr blr blr 1B (Min C) blr blr blr blr 12 blr blr 4 blr blr blr blr blr 3A (A(2)) blr blr blr blr 6 blr blr blr blr blr blr blr blr 3C (A(2)) blr blr blr blr 7 blr blr blr blr blr blr blr bl Note: blr (below laboratory level of reporting)
The analytical results indicated no severe limiting chemical characteristics for the soils sampled. Plant growth is generally best within a pH range of 6 to 7.5. Soils sampled in the mining area exhibited pHs between 6.1 and 8.3 with higher pH values generally found lower in the profile (within soils with a higher calcareous content).
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Soil EC, a measure of soil salinity, was found to be at a low level, suitable for growing a wide range of plant species. Similarly, soil sodicity, a measure of exchangeable sodium and soil dispersion potential, was also very low in the surface soils. Low sodicity levels suggest that it is unlikely that significant problems with soil surface crusting, which may impede seedling emergence during revegetation, would occur. However, high sodicity clays are know to occur at the base of the root zone in many areas.
Organic matter (carbon) levels of the soil samples are typical of uncultivated Australian topsoils in dry inland areas ranging from 0.22 to 1.88%. Organic contents are likely to be lower in soils under cultivation and are dependent on cropping history, tillage practices, and the amount and nature of organic material removed from, or returned to, the soil.
Most trace element concentrations in soil samples were either below the laboratory limits of reporting (B, Be, Cd, Cu, Mo, Pb, Sb, Se, Sn) or at levels that are unlikely to have any phytotoxic effects during minesite revegetation (As, Cr, Ni, Zn). Boron levels, however, may be found within the B-horizons of many soil profiles within the area. Boron concentrations exceeding 15 mg/kg may damage cereal crops, but phytotoxic effects may be seen in some horticultural crops at much lower levels (van Rees and Pedley, 1999).
Significant amounts of salt are stored in the deep unsaturated profile between the soil surface and the water table (about 50-60 m) in the lease areas near Mindarie.Calculated
maximum salinities, measured by electrical conductivity (ECSE) for the site are shown in Table 4.9 below. These values can be compared to salinity threshold values for relevant
crops that are likely to be grown in the area. The threshold value is the ECSE value in deciSiemens/metre (dS/m) that results in a measurable decrease in yield (Department of Natural Resources Queensland, 1997). Table 4.10 below shows the threshold values for a number of crops as well as the soil salinities that produce decreases in yield to 90%, 75%, or 50%, respectively.
Table 4.9 Calculated maximum salinity (ECSE)
Site Depth (m below surface) ECSE (dS/m) Mindarie C 10.5 3.7
Table 4.10 Plant salt-tolerance data
Crop Salinity Soil salinity ECSE dS/m threshold 90% yield 75% yield 50 %yield dS/m Barley, grain 8.0 10.0 13.0 18.0 Wheat 6.0 7.4 9.5 13.0 Oats 5.0 5.5 6.3 7.5 Lucerne 2.0 3.7 6.2 10.3 Potato 1.7 2.5 3.8 5.9 Carrot 1.0 1.7 2.8 4.5 From Department of Natural Resources Queensland, 1997.
The above data demonstrates that care must be taken to avoid bringing materials into the plant root-zone that could reduce productivity due to boron toxicity or increased salinity. This
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has lead to the commitment from MZ to sample profiles ahead of mining and to remove and replace topsoil and subsoil separately (refer to Section 8).
Soil Assessment (2009) – eastern portion of Mindarie A(2)
A soil assessment of the previously mined areas of the eastern portion of the Mindarie A(2) strandline was conducted in 2009. This soil assessment study was conducted to assess the soil quality in order to determine the most appropriate rehabilitaiton management measures for replacement of dryland cropping. Results of the soil assessment indicated varying capacity of the post mined Mindarie A(2) strandline to accommodate dryland cropping in its current statedue to (Rural Solutions 2009a):
low fertility and water holding capacity exhibited by the deep sand hills heavier textured soils to a depth of 900 mm in some locations with no severe levels of salinity or sodicity some sites exhibiting severe chemical constraints to cereal root growth within the top 900 mm.
The soil test results show in almost all heavier soil types a spike in the Exchangeable Sodium Percentage or Cation % Na in the 100 to 200 cm soil layer, often at levels that would cause some soil structural problems and impede root function. These soils are expected to respond to the application of gypsum in the surface (Rural Solutions 2009a).
4.6.3.1 Soil density
Issues have arisen with access of farm vehicles in areas which have been rehabilitated after ceasing of mining on the Mindarie A(2) and Mindarie C strandlines. The key issue was bogging of machinery during the 2010 harvesting period. A study was undertaken in May 2011 to determine the likely causes of the bogging issue found the the likely causes to include:
an unusually wet December causing a wet layer to develop on top of the clayey soil the presence of loose sandy soil which has not had time to compact post mining operations imperfect soil drainage.
A soil density study comparing areas which have been rehabilitated as cropping land with adjacent land has also been carried out. The soil density study was conducted by completing 62 dynamic cone penetration tests (DCPT) to a maximum depth of 1.7 m at regular intervals along the five nominated traverses of the Mindarie Mineral Sands Project site. The DCPT method records the number of blows per distance (blows per 100 mm) of rod penetration by dropping a 9 kg hammer a set distance each time. In general, the higher the number of blows to penetrate a 100 mm distance the stronger (higher strength/density) the soil profile and generally direct comparisons can be made between soil profiles using this method.
Results of the study indicate:
that some variability in soil density exists in both natural and rehabilitated areas there is an increased variability in soil density in rehabilitated areas there is a reduced soil density in the rehabilitated areas tested, particularly at depths greater than 0.3 m significantly more locations were encountered with blow counts <2 per 100 mm in the rehabilitated areas – approximately 30% of results in assumed rehabilitated areas
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tested, compared to only 12% of results from the DCPTs conducted in the assumed natural material
In interpretation of these results, it should be noted that:
The boundary between natural and rehabilitated areas was only approximate. It is possible that some of the readings stated as natural could in fact be from rehabilitated areas, and vice versa.
The previous presence of a stockpile area on the northern side of the mine site may have led to consolidation over these areas which could increase the density and hence affect the Blow Count of the natural soils.
The top 300 mm depth of all locations had been tilled as part of cropping and therefore could be expected to have reduced densities.
The potential presence of cobbles within the rehabilitated area. Fill cobbles may cause DCPT results to produce very high blow counts or meet refusal, which is not representative of the true ground conditions.
The variability between the natural and rehabilitated areas is unlikely to be the controlling influence on trafficability of farming equipment. Other factors, such as the high rainfall that was experienced in the area and the topography (such as the presence of low lying areas) could impact the density of the near surface soils.
4.7 Surface water
In common with other parts of the Murray Mallee in South Australia, there are no significant natural surface water resources away from the Murray River in the area containing MZ’s known mineral sand resources.
Surface water drainage is practically non-existent in the Murray Mallee, due to the generally low relief, low rainfall and highly permeable soils. The only significant natural surface water is the Murray River located around 45 km west of the project site.
4.8 Groundwater
4.8.1 Regional
The project area is located in the Mallee Region of the Murray Basin, where there are five main hydrogeological units (Barnett and Yan, 2000). The units in order of increasing depth below the surface are:
Pliocene Sands: A generally unconfined aquifer that is not saturated in the study project and is not considered further, although all wells in the study projectwould pass through this layer before reaching water.
Bookpurnong Beds (confining layer): This low-permeability unit is absent in most of the project area, notably the western part. However, it becomes hydrogeologically relevant approximately 25 km east of Mindarie, where it causes the underlying Murray Group Limestone Aquifer to be confined.
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Murray Group Limestone Aquifer: This occurs as an unconfined aquifer over the majority of the project area with the exception of an area east of Mindarie as noted above. It comprises a consolidated, fossil-rich limestone typically 100 m thick, of which about 80 m is saturated over most of the project area. Where the aquifer is confined, it is saturated to the full thickness. The salinity of the groundwater ranges from 1,000 to 3,000 mg/L total dissolved solids (TDS) in the project area (1,200 to 1,500 mg/L TDS under the Mindarie A(2) deposit).
Ettrick Formation (confining layer): This is low-permeability, glauconitic and fossiliferous marl about 15 m thick.
Renmark Group Aquifer: A confined aquifer comprising unconsolidated carbonaceous sands, silt and clay around 150 m thick. Water from this aquifer is expected to have a salinity of between 1,000 and 3,000 mg/L in the project area.
The hydrogeology of the project area is indicated on the Pinnaroo 1:250,000 Murray Basin Hydrogeological Maps (Barnett/SADME 1993).
Regional groundwater levels, direction of flow and salinity is towards the River Murray and varies from north to west in the general area. In the area of MZ’s deposits typical groundwater movement is between 0.1 and 0.2 m/yr (S. Barnett pers. comm. in Parsons Brinckerhoff 2006)
The climate of the project area is semi-arid. Current and recent recharge of the aquifer is small, in the order of 0.1 to 1 mm/yr or less in areas with native vegetation (Allison and Hughes 1983 in Parsons Brinckerhoff 2003), although this may be up to 100 mm/yr where soils are sandy and the land has been cleared for agriculture (Kennett-Smith et al. 1994 in Parsons Brinckerhoff 2003). In the project area, it is considered that the increased recharge has not yet reached the aquifer due to the deep unsaturated layer of 40–60 m (Barnett and Yan 2000, Leaney and Herczeg 1999 in Parsons Brinckerhoff 2003). When this occurs, an increase in water levels and groundwater salinity (at least of the upper part of the unsaturated aquifer) is expected to occur, probably in a time frame of 100–150 years. Water level rises due to increased post-clearing recharge have not been observed in the project area to date (S. Barnett pers. comm. in Parsons Brinckerhoff 2003).
A review of water well records from the Mindarie Mineral Sands Project area indicates that the depth to groundwater ranges from 40 to 60 m below surface, with 50 m considered typical. Recorded yields vary from 5 to 50 L/s. Most wells in the area are shallow stock and domestic wells and do not penetrate very far into the Murray Group aquifer (Figure 4.8, Appendix L). The aquifer is considered capable of sustained yields in the upper part in the range 5 to 50 L/s if wells intercept the entire saturated thickness of the Murray Group limestones.
Rainwater collection is common in houses, but town, irrigation and industrial water supplies are obtained from groundwater.
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4.9 Fauna and flora
4.9.1 Flora
4.9.1.1 Mindarie C
Environmental and Biodiversity Services (EBS) conducted an ecological assessment of the Mindarie C strandline in February 2008. A copy of this report is available in Appendix D. Native vegetation within the strandline was assessed to determine the vegetation associations present and the condition of the overall biological significance of the native vegetation in accordance with the ‘Guide to Roadside Vegetation Survey Methodology for South Australia’ (Stokes et al 1998).
A literature review and database searches were undertaken to determine the likely presence of flora species within or near the strandline. Database searches for flora species included the Department for Environment and Natural Resources’ Biological Databases of South Australia (BDBSA) and the EPBC Online Database (Protected Matters Search Tool). The literature review included the Biodiversity Plan for the South Australian Murray-Darling Basin and relevant management plans for the nearby Conservation Parks.
Regional flora
The Mindarie C strandline occurs in an area where native vegetation has been extensively cleared for agricultural purposes.
The project area falls within the Kunlara Environmental Association (2.4.1) and the Holder Environmental Association (2.4.9) and is described as an undulating calcrete plain with extensive sand sheets, low dunes and shallow depressions (Government of South Australia 2007). Vegetation varies from disturbed mallee scrub to open parkland and grassland. The dunes have been cleared to open parkland but elsewhere the vegetative cover is cultural grassland used for cereal cultivation and grazing (Government of South Australia 2007).
The Kunlara Environmental Association contains approximately 9% of remnant vegetation (DEH 2002) and the Holder Environmental Association contains approximately 18% of remnant vegetation. Additionally, the site is located within the Hundred of Mindarie, which contains approximately 11% of its original vegetation (DEH 2002), and the Hundred of Chesson, which contains approximately 6% of its original vegetation (DEH 2002). These percentages are considered to be low and reveal limited native vegetation remains within the area.
Site vegetation communities
Eleven vegetation associations were observed by EBS and are summarised below. The location of these associations is detailed on Figure 4.9 (Appendix L).
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Vegetation Association 1 Eucalyptus calycogona ssp calycogona (Square-fruit Mallee)/Maireana brevifolia (Short-leaf Bluebush) Open Mallee
Overstorey species Eucalyptus calycogona ssp calycogona (Square-fruit Mallee) Emergent species Eucalyptus socialis (Red Mallee) Common understory Maireana brevifolia (Short-leaf Bluebush), Salsola kali (Buckbush), species Enchylaena tomentosa var. tomentosa (Ruby Saltbush) Landform Loamy flat Condition Moderate Common weed species Avena barbata (Wild Oats), Echium plantagineum (Salvation Jane), Emex australis (Three Cornered-jack), Salvia verbenaca (Wild Sage)
Vegetation Association 2 Maireana brevifolia (Short-leaf Bluebush)/Exotic grassland Open Shrubland
Overstorey species Non recorded Emergent species None recorded Common understory Maireana brevifolia (Short-leaf Bluebush), Salsola kali (Buckbush), species Enchylaena tomentosa var. tomentosa (Ruby Saltbush), Austrostipa nodosa (Tall Spear-grass) Landform Loamy flat Condition Very poor/poor Common weed species Avena barbata (Wild Oats), Chondrilla juncea (Skeleton Weed), Cirsium vulgare (Spear Thistle), Echium plantagineum (Salvation Jane), Emex australis (Three Cornered-jack), Salvia verbenaca (Wild Sage), Heliotropium europaeum (Common Heliotrope), Marrubium vulgare (Horehound), Asphodelus fistulosus (Onion Weed)
Vegetation Association 3 Atriplex nummularia ssp. (Old–man Saltbush) Plantation
Overstorey species None recorded Emergent species None recorded Common understory None recorded species Landform Loamy flat/sandy plains and rises Condition Not applicable Common weed species None recorded
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Vegetation Association 4 Eucalyptus socialis (Red Mallee)/Eucalyptus calycogona ssp calycogona (Square-fruit Mallee)/Maireana brevifolia (Short–leaf Bluebush) Open Mallee
Overstorey species Eucalyptus socialis (Red Mallee), Eucalyptus calycogona ssp calycogona (Square-fruit Mallee) Emergent species None recorded Common understory Dodonaea viscosa ssp. angustissima (Narrow-leaf Hop-bush), species Maireana brevifolia (Short-leaf Bluebush), Maireana erioclada (Rosy Bluebush) Salsola kali (Buckbush), Enchylaena tomentosa var. tomentosa (Ruby Saltbush), Austrostipa nodosa (Tall Spear-grass), Austrodanthonia caespitosa (Common Wallaby-grass), Austrodanthonia setacea (Small-flower Wallaby-grass) Landform Loamy flat Condition Moderate Common weed species Avena barbata (Wild Oats), Chondrilla juncea (Skeleton Weed), Echium plantagineum (Salvation Jane), Emex australis (Three Cornered-jack), Salvia verbenaca (Wild Sage), Heliotropium europaeum (Common Heliotrope), Marrubium vulgare (Horehound), Asphodelus fistulosus (Onion Weed)
Vegetation Association 5 Eucalyptus oleosa (Red Mallee) Open Mallee
Overstorey species Eucalyptus oleosa (Red Mallee), Eucalyptus oleosa ssp. oleosa (Red Mallee), Eucalyptus calycogona ssp calycogona (Square-fruit Mallee), Eucalyptus gracilis (Yorrell) Emergent species Melaleuca lanceolata (Dryland Tea-tree) Common understory Maireana brevifolia (Short-leaf Bluebush), Salsola kali (Buckbush), species Enchylaena tomentosa var. tomentosa (Ruby Saltbush), Austrostipa nodosa (Tall Spear-grass) Landform Loamy flat/sandy rise Condition Moderate Common weed species Citrullus lanatus (Bitter Melon), Emex australis (Three Cornered-jack), Ehrharta calycina (Perennial Veldt-grass), Mesembryanthemum crystallinum (Common Iceplant)
Vegetation Association 6 Eucalyptus incrassata var. incrassata (Ridge fruited Mallee) Open Mallee
Overstorey species Eucalyptus incrassata var. incrassata (Ridge fruited Mallee) Emergent species Melaleuca lanceolata (Dryland Tea-tree), Melaleuca uncinata (Broombush) Common understory Maireana brevifolia (Short-leaf Bluebush), Maireana erioclada (Rosy species Bluebush) Salsola kali (Buckbush), Enchylaena tomentosa var. tomentosa (Ruby Saltbush), Austrostipa nodosa (Tall Spear-grass), Austrodanthonia caespitosa (Common Wallaby-grass), Austrodanthonia setacea (Small-flower Wallaby-grass), Enneapogon nigricans (Black- head Grass) Landform Sandy rise/low dune Condition Moderate Common weed species Avena barbata (Wild Oats), Chondrilla juncea (Skeleton Weed), Echium plantagineum (Salvation Jane), Emex australis (Three Cornered-jack), Salvia verbenaca (Wild Sage), Asphodelus fistulosus (Onion Weed)
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Vegetation Association 7 Eucalyptus oleosa (Red Mallee)/Eucalyptus incrassata var. incrassata (Ridge fruited Mallee) Open Mallee
Overstorey species Eucalyptus oleosa (Red Mallee), Eucalyptus incrassata var. incrassata (Ridge fruited Mallee) Emergent species Melaleuca lanceolata (Dryland Tea-tree), Leptospermum coriaceum (Dune Tea-tree) Common understory Carpobrotus modestus (Inland Pigface), Enchylaena tomentosa var. species tomentosa (Ruby Saltbush), Acacia rigens (Nealie), Acacia nyssophylla (Spine Bush) Triodia scariosa (Spinifex), Austrodanthonia caespitosa (Common Wallaby-grass), Enneapogon nigricans (Black-head Grass) Landform Loamy flat Condition Poor/Moderate Common weed species Ehrharta calycina (Perennial Veldt-grass), Salvia verbenaca (Wild Sage), Asphodelus fistulosus (Onion Weed)
Vegetation Association 8 Revegetation area
Revegetation species Eucalyptus calycogona ssp calycogona (Square-fruit Mallee), Acacia brachybotrya (Grey Mulga-bush), Acacia notabilis (Notable Wattle), Acacia nyssophylla (Spine Bush), Acacia rigens (Nealie), Callitris gracilis (Southern Cypress Pine), Dodonaea viscosa ssp. angustissima (Narrow-leaf Hop-bush) Landform Loamy flat Common weed species Ehrharta calycina (Perennial Veldt-grass), Salvia verbenaca (Wild Sage), Asphodelus fistulosus (Onion Weed)
Vegetation Association 9 Eucalyptus calycogona ssp calycogona (Square-fruit Mallee)/Eucalyptus incrassata var. incrassata (Ridge fruited Mallee) Open Mallee
Overstorey species Eucalyptus calycogona ssp calycogona (Square-fruit Mallee), Eucalyptus. incrassata var. incrassata (Ridge fruited Mallee) Emergent species Melaleuca lanceolata (Dryland Tea-tree) Common understory Carpobrotus modestus (Inland Pigface), Enchylaena tomentosa var. species tomentosa (Ruby Saltbush), Maireana brevifolia (Short-leaf Bluebush), Maireana erioclada (Rosy Bluebush) Salsola kali (Buckbush), Triodia scariosa (Spinifex), Austrodanthonia caespitosa (Common Wallaby- grass), Enneapogon nigricans (Black-head Grass), Acacia rigens (Nealie), Eremophila crassifolia (Thick-leaf Emubush) Landform Loamy flat/sandy rise Condition Moderate Common weed species Ehrharta calycina (Perennial Veldt-grass), Salvia verbenaca (Wild Sage), Asphodelus fistulosus (Onion Weed), Avena barbata (Wild oats)
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Vegetation Association 10 Paddock/grazing land
Overstorey species None recorded Emergent species None recorded Scattered native Carpobrotus modestus (Inland Pigface), Enchylaena tomentosa var. species (other than tomentosa (Ruby Saltbush), Eremophila crassifolia (Thick-leaf scattered trees) Emubush), Austrodanthonia caespitosa (Common Wallaby-grass), Enneapogon nigricans (Black-head Grass) Salsola kali (Buckbush), Austrostipa nodosa (Tall Spear-grass), Dampiera lanceolata var. lanceolata (Grooved Dampiera), Lomandra leucocephala ssp. robusta (Woolly Mat-rush) Landform Loamy flat/sandy plains and rises Condition Very poor/poor Common weed species Ehrharta calycina (Perennial Veldt-grass), Salvia verbenaca (Wild Sage), Asphodelus fistulosus (Onion Weed), Avena barbata (Wild Oats), Chondrilla juncea (Skeleton Weed), Cirsium vulgare (Spear Thistle), Echium plantagineum (Salvation Jane), Citrullus lanatus (Bitter Melon), Marrubium vulgare (Horehound), Oenothera stricta ssp. stricta (Common Evening Primrose)
Vegetation Association 11 Grevillea pterosperma (Dune Grevillea)/Acacia brachybotrya (Grey Mulga-bush) Open Shrubland
Overstorey species Grevillea pterosperma (Dune Grevillea), Acacia brachybotrya (Grey Mulga-bush) Emergent species None recorded Common understory Acacia pravifolia (Coil-pod Wattle) species Landform Low dune Condition Moderate Common weed species Salvia verbenaca (Wild Sage), Asphodelus fistulosus (Onion Weed)
Flora species of conservation significance
Flora species of conservation significance are discussed below (DENR 2010):
Acacia notabilis (Notable Wattle) is listed as regionally rare. It was found within Vegetation Association 8. Aristida holathera var. holathera (Tall Kerosene Grass) is listed as regionally rare. It was found within Vegetation Association 10.
Both species were found in the project area during the 2008 EBS survey, however no species of a State or National conservation significance were recorded during the survey.
4.9.2 Mindarie A(2)
The Mindarie A(2) strandline has undergone mining activities which have significantly altered the pre-mining vegetation within the mining affected areas. As with the Mindarie C strandline
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the majority of the Mindarie A(2) strandline was comprised of dryland cropping with only small areas of native vegetation present (as shown in Figure 4.9, Appendix L).
Four native Vegetation Associations and two non-native Vegetation Associations occurred along the Mindarie A(2) ML and included (EBS 2005)as follows:
Aristida contorta – Native Grassland Eucalyptus Dumosa – Open Mallee Maireana brevifolia Open Shrubland Eucalyptus cyanophylla +/- E. socialis – Open Mallee exotic grassland cropping.
A total area of 9.86 ha of native vegetation was cleared for the mining of Mindarie A(2), comprising:
Eucalyptus dumosa Open Mallee association native/exotic grassland as a sparse occurrence on a sandhill native grassland Aristida contorta.
Upon completion of mining activities the replanting of approximately 1.5 ha of Native Vegetation along Knights Well Road occurred in 2008. Due to losses during the summer months 387 new native tube stock were planted in July 2009 to replace trees that had died in the original planting.
The remainder of the vegetation that was affected within the Mindarie A(2) mining lease was dryland cropping. These areas have either been rehabilitated or are currently being rehabilitated.
4.9.3 Fauna
4.9.3.1 Mindarie C
Environmental and Biodiversity Services (EBS) conducted an ecological assessment of the Mindarie C strandline in February 2008. A copy of this report is available in Appendix D. An assessment of the habitat quality for fauna species was undertaken as well as recording any fauna species which were observed within the strandline.
A literature review and database searches were undertaken to determine the likely presence of fauna species within or near the strandline. Database searches for flora species included the Department for Environment and Natural Resources’ BDBSA and the EPBC Online Database (Protected Matters Search Tool). The literature review included the Biodiversity Plan for the South Australian Murray-Darling Basin and relevant management plans for the nearby Conservation Parks.
Habitat
The habitat value of the scattered trees is considered valuable for birds due to the scarcity of vegetation within the area however none of these trees contained hollows (EBS 2008).
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Site fauna
A total of ten fauna species were observed within the project area, with no species of national or state conservation significance being observed.
A possible reason that the data bases indicate low numbers of fauna species in the general project area is probably related to the number of biological surveys and the number of opportunistic recordings of fauna for the area. Their absence within databases is not necessarily justification for their absence on site.
Fauna species of conservation significance
The BDBSA includes records of three fauna species which have been previously recorded in the vicinity of the Mindarie C strandline (DEH 2008). One of the recorded species Leipoa ocellata (Malleefowl) has a national rating of Vulnerable under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).
A total of six fauna species of national significance, listed under the EPBC Act, have been listed as possibly occurring within close vicinity to the project area from a search of the EPBC Act Protected Matters Database. These six animal species are discussed below:
Leipoa ocellata (Malleefowl) is listed as Vulnerable. It is unlikely to occur because the project site contains no suitable habitat.
Pachycephala rufogularis (Red-lored Whistler) is listed as Vulnerable. It is possible that it may occur within the Roadside Mallee vegetation of the project site however, generally it relies on larger tracts of mallee to persist in an area.
Polytelis anthopeplus monarchoides (Regent Parrot) is listed as Vulnerable. It is unlikely to occur because the project site contains no suitable habitat.
Rostratula australis (Australian Painted Snipe) is listed as Vulnerable. It is unlikely to occur because the project site contains no suitable habitat.
Stipiturus mallee (Mallee Emu-wren) is listed as Endangered. It is unlikely to occur because the project site contains no suitable habitat.
Nyctophilus corbeni, South-eastern form (Eastern Long-eared Bat) is listed as Vulnerable. It is possible that it may occur infrequently (feeding) within the Roadside Mallee vegetation of the project site. However, it has not previously been recorded in the region and limited habitat is available for the species within the project area.
4.9.3.2 Mindarie A(2)
The majority of the Mindarie A(2) strandline has been returned to agricultural land which has little value for native fauna species. Areas containing the Exotic Grassland, Maireana brevifolia (short-leafed bluebush) Open Shrubland and scattered native grass areas surveyed prior to mining operations were considered to provide low habitat value for wildlife. These areas may however, provide suitable habitat for pest speices such as mice (Mus musculus), hence would provide suitable foraging areas for birds of prey and reptiles (e.g. brown snake). The areas may also provide suitable habitat for large native mammals (e.g. kangaroos).
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4.9.4 Pest plants and animals
4.9.4.1 Mindarie C
Pest plants
Seven weed species identified during the ecological survey are listed as declared under the Natural Resources Management Act, 2004 and an additional five weed species are considered to be serious environmental weed species. These weed species are discussed below:
Asphodelus fistulosus (Onion Weed) is classed as a declared weed. It was found within Groups 2, 4, 6, 7, 8, 9, 10 and 11. Common particularly within Vegetation Association 10.
Chondrilla juncea (Skeleton Weed) is classed as a declared weed. It was found within Groups 2, 4 and 10. Common particularly within Vegetation Association 10.
Cirsium vulgare (Spear Thistle) is classed as a declared weed. It was commonly found within Vegetation Associations 2 and 10.
Echium plantagineum (Salvation Jane) is classed as a declared weed. It was found within Groups 1, 2, 4, 6, and 10. Common particularly within Vegetation Association 10.
Ehrharta calycina (Perennial Veldt Grass) is classed as an environmental weed. It was commonly found within Vegetation Association 10. Scattered individuals were found within Vegetation Associations 5, 7, 8 and 9.
Ehrharta villosa var. maxima (Pyp Grass) is classed as an environmental weed. Scattered small groups were found within Vegetation Associations 5 and 10.
Emex australis (Three-corner Jack) is classed as a declared weed. Scattered individuals were found within Vegetation Associations 1, 2, 4, 5 and 6.
Euphorbia terracina (False Caper) is classed as a declared weed. It was commonly found within Vegetation Association 10. Scattered individuals within Vegetation Associations 7, 8 and 9.
Marrubium vulgare (Horehound) is classed as a declared weed. It was commonly found within Vegetation Association 10. Scattered small groups within Vegetation Associations 2 and 4.
Mesembryanthemum crystallinum (Common Iceplant) is classed as an environmental weed. It was commonly found within Vegetation Association 10. Scattered small groups within Vegetation Associations 1, 2, 4, 5 and 6.
Oenothera stricta ssp. stricta (Common Evening Primrose) is classed as an environmental weed. It was commonly found within Vegetation Association 10. Scattered small groups within Vegetation Associations 2 and 4.
Sorghum halepense (Johnson Grass) is classed as an environmental weed. It was found in a small patch (roadside) within Vegetation Association 2.
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Pest animals
Oryctolagus cuniculus (European Rabbit) and Vulpes vulpes (European Red Fox) were the only pest animal species observed during the project survey.
Pathogens
The project site is not located in a high risk Phytophthora or Mundulla Yellows area within the state.
4.9.4.2 Mindarie A(2)
A weed and pest survey conducted in 2009 on the eastern portion of the Mindarie A(2) strandline identified the following species (Rural Solutions 2009b):
Amsinckia spp. (Yellow Burr-weed) Asphodelus fistulosus (Onion Weed) – classed as a declared weed. Cenchrus incertus and Cenchrus longispinus (Innocent Weed) Chondrilla juncea (Skeleton Weed) – classed as a declared weed Cirsium vulgare (Spear Thistle) – classed as a declared weed Echium plantagineum (Salvation Jane) – classed as a declared weed Emex australis (Three Corner Jack) – classed as an environmental weed Euphorbia terracina (False Creeper) – classed as an environmental weed Marrubium vulgare (Horehound) – classed as an environmental weed Tribulus terrestris (Caltrop) Xanthium spinosum (Bathurst Burr) Oryctolagus cuniculus (European Rabbit) Vulpes vulpes (Red Fox)
In the broader South Australian Murray Darling Basin area problem feral animals include: rabbits, Capra hircus (goats), foxes and Felis catus (cats). In addition, several native species threaten biodiversity and rehabilitation projects when in large numbers such as Macropus fuliginosus (Western Grey Kangaroo), Eolophus roseicapilla (Galah) and Cacatua sanguinea (Corella).
4.10 Heritage
4.10.1 Indigenous heritage
Prior to European settlement, the Murray Mallee was populated by Aboriginal peoples who belonged to two cultural groups, the Ngarkat and Ngintait. These groups were reliant on water from soaks scattered throughout the region, and had access to River Murray waters during times of drought. Their numbers appear to have been limited by the poor water supply and there are signs that they ranged widely through this region (Parsons Brinckerhoff, 2006).
Although the land to be mined is mostly used for farming with extensive modification of landscape by vegetation clearance and its history of agricultural use, Australian Zircon (as Southern Titanium) carried out an Access Clearance Survey in 2006. There are no previously recorded sites on the Register of Aboriginal Site and Objects, maintained by the Department of Aboriginal Affairs and Reconciliation within the project study region. During the 2006 one area adjacent to the Mindarie C strandline was considered to be of significance by representatives of the Mannum Aboriginal Community Association Incorporated (refer to Figure 4.10, Appendix L) (Wood 2006).
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4.10.2 Non-Indigenous heritage
There are a number of non-Indigenous heritage items located within the District Council of Karoonda East Murray. Details of these items and their distance from the Mindarie C and Mindarie A(2) strandlines are summarised in Table 4.11.
Table 4.11 Non indigenous heritage items, District Council of Karoonda East Murray Area
Item Location Distance from Listing the operations (km) Billiatt Conservation Park Halidon 10 Register of the National Estate Elizabeth Well Mercunda North 9 Register of the National Estate Lowan Conservation Park Perponda 48 Register of the National Estate Nildottie Well Bakara 27 Register of the National Estate State Heritage Register Elizabeth Well including Mercunda North 9 State Heritage Register Water Tank, Drinking Troughs and Cottage (ruin) All Hallows Anglican Karoonda 44 Murray Mallee Heritage Survey Church Area School Karoonda 44 Murray Mallee Heritage Survey Cemetery Galga 9.5 Murray Mallee Heritage Survey Community Hall Mantung 15 Murray Mallee Heritage Survey Community Hall Sandalwood 18 Murray Mallee Heritage Survey Community Hall Wanbi 4 Murray Mallee Heritage Survey Community Hall Wynarka 57 Murray Mallee Heritage Survey Former Community Hall Mercunda North 9 Murray Mallee Heritage Survey Former East Murray Halidon 8.5 Murray Mallee Heritage Survey Council Chambers Former Institute Borrika 28.5 Murray Mallee Heritage Survey Former School House Mindarie 0.5 Murray Mallee Heritage Survey Former Schoolhouse Wanbi 4 Murray Mallee Heritage Survey Former Shop/Residence Sandalwood 18 Murray Mallee Heritage Survey Lutheran Cemetery Via Bakara 27 Murray Mallee Heritage Survey Lutheran Church Via Bakara 27 Murray Mallee Heritage Survey Masonic Lodge Karoonda 44 Murray Mallee Heritage Survey Our Redeemer Lutheran Perponda 35.5 Murray Mallee Heritage Survey Church Post Office Karoonda 44 Murray Mallee Heritage Survey Railway Station Karoonda 44 Murray Mallee Heritage Survey Simpson’s Hotel Wanbi 4 Murray Mallee Heritage Survey St Finian’s Catholic church Karoonda 44 Murray Mallee Heritage Survey St John’s Lutheran Church Karoonda 44 Murray Mallee Heritage Survey Turner Well Via Kalyan 30 Murray Mallee Heritage Survey Uniting Church Karoonda 44 Murray Mallee Heritage Survey Water Tank Mindarie 0.5 Murray Mallee Heritage Survey
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4.11 Proximity to conservation areas
The closet conservation area to the Mindarie C strandline is the Billiatt Conservation Park and Wilderness Area located approximately 10 km southeast of the Mindarie C Strandline. Other conservation areas within the region include
Bakara Conservation Park (approximately 36 km northwest) Karte Conservation Park (approximately 50 km southeast) Lowan Conservation Park (approximately 56 km southwest) Peebinga Conservation Park (approximately 56 km southeast)
Figure 4.11 (Appendix L) indicates the location of conservation areas in relation to the Mindarie C strandline.
4.12 Pre-existing site contamination and disturbance
Disturbance and contaminating activities within the project area primarily include the previous mining activities associated with AZ (including the MSP and PCP) and the current and future planned rehabilitation works. In 2006 AZ was given approval to commence construction activities in order to mine the Mindarie strandlines. Site establishment and construction activities for Mindarie A(2) commenced in 2006. Following construction and commissioning of plant and equipment, mining of mineral sands in the A(2) strandline commenced in April 2007.
AZ commenced mining operations on the Mindarie C strand (refer Figure 1.2, Appendix L) in July 2009 with mining activities commencing in a section of the strand immediately west of the Loxton – Murray Bridge Road (approximately 20.42 ha in size). In October 2009 mining activities ceased when AZ went into Voluntary Administration.
MZ has made significant progress on the rehabilitation of the Mindarie A(2) and Mindarie C strandlines where mining had been undertaken. Current activities within the project area are focused on rehabilitating Mindarie C and Mindarie A(2) strandlines that have an approximate combined area of 255 ha.
Figure 4.12 (Appendix L) shows the Mindarie A(2) and Mindarie C strandlines and outlines the areas which are currently undergoing rehabilitation or planned to be rehabilitated over the next 12 months. This is discussed in further detail in Section 5.19.
4.13 Socio-economic
The Mindarie project area lies in the Karoonda East Murray District Council area, with Karoonda being the largest populated centre in the vicinity of the mineral sands site.
Karoonda is home to 317 families; with 44.8% with children and 42.2% of individuals between the ages of 25–54. The median household income in the area is $634 per week, which is significantly lower than the Australian median household income of $1,027 per week (ABS Census Data, 2006). The main income for 46% of the labour workforce is derived from the sheep, beef cattle and grain farming industries. The next most populated industry is school education, employing 6% of the Karoonda East Murray District Council workforce (ABS Census Data, 2006).
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4.14 Transport and traffic
The current regional road and rail network is shown in Figure 4.13 (Appendix L) and comprises of the following main elements:
The Tailem Bend-Loxton railway line. The land and infrastructure are ‘owned’ by the Department of Planning, Transport and Infrastructure (DTPI) and leased to Genesee Wyoming Australia.
The main Murray Bridge-Loxton arterial road. This is a sealed road, maintained by DPTI, providing an inter-regional function. It links Mindarie and Loxton with Murray Bridge to the southwest, and less directly with Tailem Bend. This road is approved by DPTI for B-Double truck use access.
Local primary roads. These link towns and farming properties, providing a reasonable level of accessibility throughout the region. These are generally Council maintained roads with gravel pavements (principally crushed limestone), in the order of 8–9 m wide. Alignment is generally adequate for local access and truck traffic, although some localised sections are of restricted alignment. Some sections of some roads have been bituminised, e.g. parts of the Mindarie-Mantung road including a section past the East Murray Area School.
Local secondary roads. These provide connectivity between the primary roads, and are typically up to 7 m in width, with narrower sections, and with some sections of poor alignment. Road surfaces are graded, and generally in reasonable condition for local traffic.
Property access roads. Typically single-track roads, their primary function is to provide access to farming properties. Their alignment does generally not support heavy truck traffic without selected upgrading to improve standards (width, alignment).
Current traffic levels on the local road network are variable, depending on road function. Primarily the road network provides for local property access with some minor inter-regional movements. The road linking Mindarie with Mantung in the north (via the East Murray Area School) is understood to attract the highest traffic flows. There is also some seasonality of flows, with increases in truck movements during harvesting periods.
There are four school buses that service the East Murray Area School with only one utilising Knights Well Road.
Currently the Mindarie Mineral Sands project experiences traffic flow as a result of ongoing rehabilitation and operational works.
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5. Project description
5.1 General description and summary
The Mindarie Mineral Sands project is an open-pit mineral sand mining operation and involves the mining of an estimated 58.1 Mt of heavy mineral reserves to a vertical depth of approximately 26 m. Mining activities will commence northwest of the Loxton – Murray Bridge Road at Section 27 moving towards Section 22 in the east. Once the western side of the strandline has been mined, the operations will move towards the eastern side of Loxton – Murray Bridge Road (refer Figure 1.2, Appendix L) with mining determined by grade control.
Mining operations on the Mindarie C strandline will occur at a production rate of 120,000 tonnes per annum (tpa) of heavy mineral concentrate (HMC) at 90% heavy minerals for approximately two years and eight months.
MZ are currently undertaking rehabilitation activities along the Mindarie A(2) strandline and will continue to do this until rehabilitation has been completed and all applicable land returned to the landowners (refer to Section 5.19 for details on the rehabilitation process).
Sections 5.1 to 5.18 below relate to the mining process proposed for Mindarie C.
5.1.1 General
In general, operations on the Mindarie C strandline will include the following and is illustrated in Figure 5.1 (Appendix L):
an open pit containing mining equipment a slurry unit – located in the open pit or on the edge of the pit a Primary Concentration Plant (PCP).
The mining method will involve the use of landplanes (tractor-scoops) or similar to strip topsoil and subsoil.
Overburden will be moved by the mining fleet (scrapers) to the back of the pit in a staged operation (refer Section 5.3.4) such that a section of the base of the pit is available for mining of ore and the remainder is used for rehabilitation purposes.
Ore will be separately excavated by the mining fleet and pushed/stockpiled at the slurry unit where it is fed into a slurry unit by a front end loader. The section of mined ore is then backfilled with tailings and/or overburden material by bulldozer, scraper or loader and/or dump trucks. The average length of the pit operations to be worked (i.e. open) at any one point in time will be approximately 2 km.
The slurry unit which is located in the mine pit screens the ore at 45 mm and mixes the extracted sand with water to form slurry which is pumped to the PCP.
The slurry pumped from the pit is again screened at 3 mm and processed through a two stage de-sliming cyclone circuit and a six stage spiral to produce HMC which is then stockpiled on site for transport initially via truck ( or rail in the future) to Port Adelaide for export (refer to Section 5.8).
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Sand ‘tails’ and clay ‘slimes’ – natural clay fraction of ore) produced from the PCP will be returned to the rear of the pit via slurry pipes. The sand tails and slimes will be combined prior to being returned to the pit void with a rheology modifier to aid clear water production and rapid rehabilitation.
Key characteristics of the project are summarised in Table 5.1.
Table 5.1 Key characteristics of the Mindarie C project
Item Description Project location Approximately 150 km east of Adelaide, South Australia Mineral lease ML6226 Project area 63 ha Mindarie C West 100 ha Mindarie C East 53 ha Mindarie C Far East Mining method Conventional open pit dry mobile hole Available minerals in HMC 90% heavy mineral grade containing zircon at 23%, rutile at 10%, ilmenite at 65% Waste to ore ratio 3:1 Mining operation 120,000 tpa HMC Treatment rate 500 tonne per hour pumped to PCP Open pit dimensions (at any given 1-2 km long, 120 m wide, 26 m deep time) Mine life Two years and eight months Hours of operations Continuous – 24 hours per day, 7 days per week Power source 66 kV overhead powerline from Pyap/Loxton substation Total power requirement 1,500 MW/month Raw water source 6 GL/yr with a maximum of 42.6GL over 10 years Transport route Trucked to Port Adelaide (possibility to transport via rail to Port Adelaide in the future) Accommodation Potential for an Accommodation Camp in Wanbi (50-80 people) Employees Operations: approximately 30–40 employees plus contractors ٭Project capital expenditure $15 million This value does not include the cost to acquire the Mindarie asset ٭
The major components of the project and their proposed footprints are identified in Table 5.2 and described in detail in the following sections. An indicative proposed project layout and location of related infrastructure is shown on Figure 5.1 (Appendix L).
Table 5.2 Mindarie C – maximum project clearance footprints
Component Mindarie C West Mindarie C East (average 270 m wide) (average 200m wide) Length and area of land that has been Length 1,950 m Length 2,650 m either stripped of topsoil or is awaiting 2 2 Area 526,550 m Area 530,000m reinstatement of topsoil
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Component Mindarie C West Mindarie C East (average 270 m wide) (average 200m wide) Length and area of land that has been Length 1,800 m Length 2,450 m either stripped of subsoil or is awaiting 2 2 Area 486,000 m Area 490,000 m reinstatement of subsoil Length and area of land that has either Length 1,500 m Length 2,050 m had overburden removed or is awaiting 2 2 Area 405,000 m Area 410,000 m reinstatement of overburden Note: Due to the varying width of the orebody the dimensions above represent the average width over the length of the proposed mined area
5.1.2 Project schedule
Table 5.3 describes the proposed project schedule for the Mindarie C project.
Table 5.3 Mindarie C project schedule
Item Target date PEPR submission December 2011 Final PEPR approval January 2012 Award mining contract January 2012 Award transport contract January 2012 Commence site works including pre-strip – Mindarie C West March 2012 Commence site works including pre-strip – Mindarie C East October 2012 Commence mining of ore April 2012 Cease production April 2014
5.1.3 Project alternatives
5.1.3.1 Mining and processing methods
The Mindarie Mineral Sands Project mining operations (which included Mindarie A(2) strandline and approximately 20.42 ha of the western portion of the Mindarie C strandline) operated from August 2007 to October 2009. During these processing operations multiple products were produced including zircon, rutile and ilmenite concentrates.
As part of the feasibility study for Mindarie C, the processing methods were reviewed for areas of improvement. The following processing issues were identified as contributing to previous poor recoveries and low success rates for the reconstitution of mining voids:
unsuitable thickener performance increase in slime in spiral feed due to recirculation and build up pumping slurry for long distances lack of instrumentation and control on all plants including PCP poor operation of settling agent (rheology modifier resulting in ‘dirty’ water and long consolidation times poor water management due to increased slimes and ineffective use of rheology modifier.
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The revised mining and processing method will address the above issues and is outlined below.
Thickener performance/rheology modifier
When the mining of Mindarie C re-commences, the rheology modifier addition will be controlled by implementing the following:
the rheology modifier make up system will be located at the PCP for better control. In the past it was located up to 4 km from the PCP which meant travelling for inspection of the unit additional instrumentation will be added to ensure that any breakdowns will be quickly identified the rheology modifier pipeline will be run with the main slurry pipeline so that it is visible and not damaged through use of heavy earthmoving equipment interlocks on the rheology unit to shut down the PCP when the rheology modifier make up system fails appointment of a dedicated supervisor in charge of the rheology modifier make up system (and flocculent for the thickener) using more recent technology developed by rheology modifier suppliers.
Additionally, to ensure thickener performance is maintained the flocculent system is required to utilise clean water (i.e. water without solids), the flocculent will be added at the correct dose and the ratio of tonnage to thickener will be limited when the thickener encounters problems. If it is not possible to produce clear water as a result of the flocculent system then the PCP will be stopped immediately and alteration to the process implemented to ensure clear water is being produced.
Poor stockpile drainage
The drainage of the HMC stockpile will be managed through development of a trench on the low side of the stockpile. This trench will slope to a sump at one end, a spindle slurry pump will be placed in the sump and the run-off water directed back to the PCP.
Additionally, there will only be HMC wet stockpiles now that the MSP is no longer required.
Increase in slime/poor water management
Slime (as measured by material passing a 45 µm screen) naturally occurs in the ore within the strandlines around the Mindarie Mineral Sands Project area. This is first removed before the spiral separation circuit in a two stage cyclone circuit. The overflows from the second cyclone cluster gravitate to the thickener, where the slime is thickened and pumped with sand tails back to the mining void. The cyclone underflows are pumped to the spiral separators and the HMC removed and the sand tails are returned with the slime.
Rheology modifier is added to the sand and slime tails when discharged into the tailings dam in the mining void. This agglomerates the sand and slime fraction and releases most of the water. If added correctly as discussed above the water release will contain little or no solids and this can be used to slurry fresh ore.
It is critical that the thickener and rheology modifier addition is undertaken in a managed process. If there are issues with either then the PCP will be stopped immediately to prevent any slime building up in the water circuit.
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Pumping slurry for long distances
Booster stations will be located adjacent to the pit to assist with slurry pumping when the PCP is greater than 2 km from the mining area. These booster pumps will be controlled via telemetry which will allow operators to control the pump speed from the control room.
In addition the pumping system will be designed by experts and the correctly matching pipes and pumps will be used.
Instrumentation and control on all plants including the PCP
During previous mining activities it had been identified that the control of levels in the sumps in the PCP caused overflows which resulted in frequent spillages. MZ will be including level sensors and control valves to overcome these issues and also develop a new operating and control philosophy to ensure easier and more efficient operation with minimal spillage.
All process modules will be provided with a local Programmable Logic Control (PLC) and a radio telemetry module. Once the individual process module is plugged into the power module, local and remote monitoring and control will be made available on that individual process module.
The PCP, process modules and mine modules can all be monitored from the Supervisory Control and Data Acquisition (SCADA) computer in the PCP control room.
Mining of ore body
The mining operation will consist of an earthmoving fleet of scrapers, bulldozers, excavators, front end loaders and dump trucks. These are standard items of equipment used in the mineral sands industry.
The method to be employed will require less stockpiling of overburden and double handling than previously required when mining Mindarie A(2) and portions of Mindarie C. A haul road will be constructed along one side of the pit to move overburden directly to the mining void behind the tailings cell. This will reduce the amount of rehandle of stockpiles from the sides of the pit and reduce the overall mining cost. In addition there is a reduction of the overall land disturbance which reduces the rehabilitation timeframe and costs.
To improve the economic viability of the mine more ore will be mined (as opposed to overburden) and this will reduce the strip ratio. Previously the average strip ratio was 7:1 meaning for each cubic metre of ore another seven cubic metres of overburden needed to be moved to expose the ore. MZ has selectively chosen areas where the overburden is less and in addition there is a lower grade layer (dune material) above the ore (strand material) which reduces the strip ratio further to around 3.2:1.
5.1.3.2 Transport routes
Transport within the Mindarie Mineral Sands Project area will utilise existing local roads and haulage routes. Additionally haulage routes will be developed adjacent to the mining area for use during mining operations (e.g. haul roads developed along the length of the strandline).
HMC will be transported to Port Adelaide using the existing local (Council) and main (DPTI) roads. A trucking Contractor will be responsible for transporting the HMC.
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MZ are currently investigating the opportunity to utilise the rail network to transport HMC to Port Adelaide and should this option be deemed economically viable MZ will commence consultation with DPTI and Genesee and Wyoming Australia in the future.
5.1.3.3 Mineral separation
Previous mining activities included the HMC transportation to the MSP for further treatment to produce marketable end products including zircon, rutile and ilmenite. These products were then railed to Port Adelaide for transport to customers.
Mineral separation is not proposed for this project.
5.1.3.4 PCP location
Currently the PCP is located adjacent to Mindarie A(2) strandline and the existing MSP within the project administration site (refer to Figure 5.6, Appendix L). This means that for mining of the western portion of Mindarie C slurry will be pumped 4 km to the current location of the PCP. When mining of the eastern portion of Mindarie C slurry will be pumped over a distance of approximately 6 km. Pumping experts have been commissioned to design a suitable pumping system to pump the 6 km.
5.2 Resources, products and markets
5.2.1 Geological environment
The Mindarie Mineral Sands Project deposits are located in the lower south-western corner of the Murray Basin. In this area, the heavily mineralised Loxton-Parilla sands are often exposed at the surface, or thinly covered by low dunes interpreted to be of Woorinen Formation (or isolated Lowan Sands dunes). From the surface, the general stratigraphic variation is unconsolidated fine to medium sands with occasional layers of sandy clay, clayey sand or clay in the top 0 to 5 m. Calcrete is also seen in the upper 0 to 5 m, usually with the clay units immediately underlying. Within the ore zone, sands are usually fine to medium, with a basal layer of very coarse to granular and occasionally pebbly sands usually up to 5 m thick.
Within the Mindarie Mineral Sands Project area, drilling has identified a series of shorelines containing strandline mineralisation of variable tenor, of which the Mindarie C deposit is a part.
The geology of the Mindarie C strandline including a cross section of the strandline is included in Section 4.6 and Figure 4.6 (Appendix L).
5.2.2 Total operations ore reserves
The mineable reserves for the Mindarie Project comprise eight individual and parallel northwest-southeast oriented strandlines up to 30 km long, several kilometres from each other. The eight separate mineral sand strandlines include the following:
Mindarie A(1) Mindarie A(2) – mining of this strandline has been completed. Mindarie C Amiens
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Mercunda Long Tan Lone Pine Halidon.
Mining of the ore reserves from the seven un-mined strandlines (excluding Mindarie A(2) and a small portion of Mindarie C, which have already been mined) will produce 58.1 million tonnes of ore containing 4.3% heavy mineral. The total heavy mineral contained from this ore reserve is estimated to be 2.5 million tonnes. These figures are considered the most up- to-date ore reserve estimates and have taken into account the mining undertaken along the Mindarie A(2) and Mindarie C strandlines.
The current identified ore reserves are estimated to provide a project life of approximately 13 years at a nominal processing rate of 3.6 million tonnes of ore per year.
The ore reserve estimate is based on a variable cut-off applied to the deposit based on the mineral assemblage for each resource block. The revenue generated from the mineral assemblage for each block and costs associated with the mining and processing have been taken into account in determining the cut-off parameters. After the application of the revenue and costs, a block was considered if the ore generates a positive cashflow. A 2.5% ore loss has been provided for in the reserve. This methodology is consistent with that of the previous 2006 Ore Reserve Statement (as provided for Mindarie A(2)).
A number of changes to the economic inputs of the previous ore reserve estimates listed below have resulted in a conservative outcome for the economic assessment of those estimates:
On the basis of experience during mining of Mindarie A(2) and Mindarie C, and mining experience in other parts of the Murray Basin indicates that an overall 60o batter angle could be applied.
The recognition of mineralised dunal material above the strandline will increase the HM inventory by increasing the overall tonnage, but reduce the average grade and the stripping ratio.
The production of an HMC will include the available monazite in some portions of the strandline which is an additional economic contributor and was not considered in the previous economic models.
Additional value will be gained through sending ilmenite overseas within the HMC.
The 63 and 45 micron limitations to the resources and reserves do not take into account the actual recovery characteristics of the PCP being 30 micron.
As part of the planned development detailed grade control drilling on a 60 m x 25 m grid is being completed in order to provide the required information for the final mine plan and scheduling of mining operations. To date this drilling has been completed over:
Mindarie A(2) – mining of this strandline has been completed and rehabilitation is underway Mindarie C West – This has resulted in a mineral resource for the unmined section of Mindarie C West of 2,875,000 t at 2.7% HM Mindarie C East – This has resulted in a mineral resource for the unmined section of Mindarie C West of 4,268,000 t at 2.5% HM Mindarie C Far East – Assaying and Resource update is on-going.
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The valuable heavy mineral content (VMC) of the total heavy mineral content (THM) and the estimated content of the material for the zircon, rutile, leucoxene and ilmenite products were determined in 2008 these figures have been updated based on conducting additional drilling utilising a grid of 60m x 25m (Snowden 2008 and Mason 2011). Table 5.4 indicates the total Mindarie Mineral Sands Project reserves, the newly estimated ore reserves for Mindarie C East and the previously estimated ore reserves for Mindarie C West.
Table 5.4 Mindarie Mineral Sands Project ore reserve estimate (2008 figures updated based on a 60m x 25m drilling grid for Mindarie C East)
millions % total % slimes Proportion of source material within heavy of heavy mineral component tonnes minerals Zircon Leucoxene Rutile Ilmenite minerals % % % % Project 58.1 4.3 11.0 21.2 6.4 4.8 64.8 Mindarie C 2.9 2.7 11.9 21.5 6.0 4.8 63.3 West Mindarie C 4.3 2.5 11.9 21.5 6.0 4.8 63.3 East Note: Does not include Mindarie Far East
5.2.2.1 Exploration
Mining within the Mindarie C strandline would commence in the south-western half of ML 6226. However, exploration drilling has shown the presence of the Mindarie C strand to extend for the full length of the mining lease and also to extend outside the lease to the southeast.
As part of the future development of the Mindarie Mineral Sands Project the remaining part of ML 6226 will require resource definition and potentially grade control drilling in order to define any additional economic areas of the strandline. This work has not been completed to date because these existing reserves are too far from the current development areas that any future mining would have to be done in conjunction with the Mercunda/Mindarie A1 operations.
The exploration drilling will be similar in nature to that already completed on Mindarie C West and Mindarie C East and consist of shallow aircore drilling, assaying, gamma logging, mineralogical and processing studies. This work is likely to be conducted over the next 5 to 8 years.
Exploration drill holes will be drilled using a Reverse Circulation Air Core method and will include:
being drilled at a nominal 75 mm diameter, 'NQ' size being drilled to less than 50 m depth samples are returned to the surface inside the rods using air water injection is sometimes also used in assisting drilling 'difficult' ground. Drilling water will be fresh water carried on the support truck, no saline water will be used drilling equipment will be mounted on 4x4 light trucks drilling support equipment is mounted on 4x4 light truck.
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Drilling will only be conducted during daylight hours. The water table is not expected to be intersected at the proposed depths of drilling. Drilling at any particular site is expected to take less than two hours
Potential impacts to vegetation will be minimised by careful siting of the drill holes to avoid damage to shrubs and trees. The exploration drill holes will be located within areas which will be mined during future operations, thus any impacts to native vegetation will be considered in the Significant Environmental Benefit offsets calculated for the project.
Rehabilitation of each drill site will occur at the completion of the hole, prior to moving to the next site and include:
backfilling of the hole with drill cuttings plugging of the hole with an Octaplug or similar at a depth of 2 m spreading remaining cuttings over the surface to minimise visual impacts checking for and removal of any rubbish or drilling materials no sumps or other excavations are required for this drilling technique.
5.2.3 Production rate, products and market
The life of mine schedule is based on the following assumptions:
only proven and probable ore reserves are included in the schedule a mining rate of 3.6 million tonnes of ore per year (one operating mine) Mindarie A(2) has been mined and was removed from the ore reserves mining of the eastern and western portions of Mindarie C and eastern section of Amiens to supply the first five years of mining, other strands could supply seven years of operation for a total mine life of 13 years.
The Mindarie C deposit is the second strandline to be developed as part of the larger Mindarie Mineral Sands Project.
The strandline has an estimated project life of approximately two years and eight months of mining and will produce approximately 10 million tonnes of ore and an estimated 0.35 million tonnes of heavy mineral.
The current mining proposal for Mindarie C West, East and Far East is associated with the south-eastern half of ML 6226. Exploration drilling has shown the presence of the Mindarie C strandline to extend for the full length of the mining lease and also to extend outside the lease to the south-east (refer Section 5.2.2.1). Mining of Mindarie C will not cut across Mc Cabe Road and Mindarie C Far East will terminate on the western side of Charleson Road. The average indicative tonnes per annumto be produced from the Mindarie Mineral Sands project is 120,000 tonnes of HMC.
5.2.4 Material movement
The HMC material will be stockpiled within the Mindarie Mineral Sands Project area adjacent to the plant site area (refer to Figure 5.14, Appendix L). Initially the HMC will be transported either via B-Double or standard trucks to Port Adelaide for shipment overseas where it will be processed. In the future HMC may be sent to Port Adelaide via the railway network (as described in Section 5.8).
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5.3 Mining operations
The following is a summary of the mining operations activities to be undertaken on the Mindarie C strandline.
5.3.1 General mine sequence
Figure 5.2 (Appendix L) indicates the mine sequence schedule for the Mindarie C strandline.
The Mindarie C West strandline will be developed as a 2.6 km long strip mine. The nominal width is for the western portion of the Mindarie C strandline is approximately 200 m. The mine process will advance at an approximate rate of 300 m/month (10 m/day).
The western portion of the Mindarie C strandline will be mined in a sequential and scheduled manner to allow for the following:
1. PCP ore requirement 2. Minimal surface disturbance where only out-of-pit overburden stockpiles are created during the initial Box-Cut stages. 3. The mine process has been designed to contain all tailings within the pit.
In this mining sequence, the intended open void consists of 1.8km at any one point in time. However with the addition of land disturbed for the haul road, stockpiles and pipelines a maximum of between 40 to 53 ha of land will be disturbed at any point in for Mindarie C West and Mindarie C East respectively.
The material movement can be described as follows:
Strip topsoil and subsoil one month prior to starting removal of overburden.
Overburden must be mined to expose ore one month prior to mining of the exposed ore. Where possible overburden will be directly returned to the back of the mining sequence, this is to avoid and minimise all double handling.
Ore from a 100 m ore block is fed into the slurry unit utilising the dozer push method to blend and homogenise ore feed to the slurry unit. This is then followed by a Front End Loader (FEL), excavator or a combination of these pending ore characteristics. The slurry unit will remains stationary for approximately 10 days. Each month, there will be three slurry unit moves.
Directly behind the ore that was pushed into the slurry unit, preparation of the material which has been depleted of ore, (under-burden), will commence for the construction of the in-pit tailings cells. Each cell will be approximately 100 m in length and the width of these cells will be proportional to the overall pit width with the exception of the requirement for the in-pit haul road. Each tailings cell will be able to contain 120% of the ore extracted from each mining block.
The in-pit haul road is required to facilitate as much direct return of overburden material ahead of the mining sequence as possible. This will reduce the overall material being double-handled.
Each tailing cell is designed to contain all returned tailings. Once a tailing cell reaches its full capacity, it will overflow into the next cell. Once this begins the tailings discharge
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outlet will be relocated to the next cell. Tailing discharge and settling will be controlled by the rheology modifiers and sump pumps. The sump pumps will pump decanted water back to the slurry unit for re-use.
The tailing cell will dry for a period of one month in order to become trafficable for overburden backfilling purposes.
Direct returned overburden material will cover the dried tailing cell to the required final contour.
As soon as the overburden is contoured and crowned, it will be ready to be rehabilitated with subsoil material followed by topsoil material.
5.3.2 Site clearance
Prior to the commencement of operations, a topographical survey will be undertaken to record the topographical profile of the area (to ensure the profile can be replaced as part of the rehabilitation program).
Site-specific soil profiles will be obtained to allow selective stripping of the topsoil and subsoil material to the necessary depths depending on salinity, pH, boron and soil texture profiles. Soil profiles will be assessed ahead of mining by augering or other drilling methods and soil samples analysed for environmental parameters (including pH, salinity, etc.) at the surface, as well as at each distinguishable soil and subsoil layer and a selection of depths to the base of each hole in the orebody.
Additional shallow holes or test pits to examine topsoil, subsoil and shallow overburden will be used based on the expected variability of soil at some locations.
5.3.3 Native vegetation, topsoil and subsoil removal and stockpiling
Prior to the commencement of mining operations, native vegetation, topsoil and subsoil will be removed and stockpiled for later use in site rehabilitation activities.
Vegetation clearance techniques will be dependent upon the types and area of native vegetation to be removed. Clearance techniques will include:
lopping of limbs removal and stockpiled for later reuse (in rehabilitation activities) chipping/mulching and separately stockpiled or left on the ground and stripped with topsoil. Chipped/mulched material will be reused in native vegetation rehabilitation activities.
Some areas will only require lopping of limbs, while other areas will require some vegetation to be removed and stockpiled for later respreading. Bulldozers, backhoes, loaders or similar will be used for areas where large amounts of native vegetation require removal. Where only low bushes are present a grader or landplane may be used.
Topsoil and subsoil will be systematically removed, and stockpiled (refer to Figure 5.1, Appendix L) to assist in the accurate rehabilitation of the land at the completion of mining.
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Landplanes (tractor-scoops) will be used to strip the soil, and soil will be stockpiled onsite for management and later used during rehabilitation activities.
The depths and corresponding volumes of topsoil and subsoil to be removed will vary along the strandline. The final removal depths will be based on the outcomes of specialist soil assessments (including Electromagnetic (EM) survey) that shall be undertaken prior to disturbance.
Topsoil and subsoil stockpile management is discussed in Section 5.11.
5.3.4 Overburden removal and stockpiling
Overburden would be mined using scrapers rather than the dozer-push or truck-excavator method as done previously.
The initial box-cut overburden will be stockpiled at an out of pit stockpile. This is required for the mining sequence to take place. Overburden stockpiles are recommended to be made as high as possible providing it is stable enough for scrapers to work on and with batters close to the natural angle of repose. Additionally, stockpile heights of 6 m or greater will reduce any noise impacts associated with mining activities on residents (Sonus 2011). It is envisaged that the average height of all out of pit overburden stockpiles be around 15 m.
Geotechnical investigations in 2001 indicated that the overburden material comprised a mixture of fine sand with some clay fines. The anticipated working overburden slope produced during operations will be 24-25° in order to maximise overburden efficiency removal and minimise the overburden pushing distances. A conservative assessment has been undertaken of the stability of the overburden stockpile which assumes that the material has no cohesion. Higher factors of safety (FOS) would be obtained if some cohesion was adopted for the analysis. Given the free draining nature of the sandy overburden soil it is expected that a water table would not develop in the overburden stockpile. Contouring of each stockpile during and after construction will be undertaken to ensure the effective drainage of rainwater.
For the stability analysis it was assumed that the stockpile could be approximated by an infinite slope. For a dry sand the FOS is independent of slope height and depends on the internal friction angle of the soil and the slope angle and can be determined by the following equation:
FOS = (tan ¢) ÷ (tan ß), where ¢ is the internal friction angle (30 degrees) and ß is the slope angle (25 degrees)
= tan 30 ÷ tan 25 = 0.577 / 0.466 = 1.24
Given the nature and timing of the mining operations and rehabilitation the factor of safety determined above is considered acceptable when compared to the industry standard FOS of 1.2.
Apart from the initial box-cut overburden stripping, other stockpiles would be created on an in-pit basis (refer to Figure 5.1, Appendix L). This equates to less out of pit surface disturbances especially when high topographical areas are mined.
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Mining of overburden will consist of three main categories: overburden to stockpile (in or out of pit), direct return overburden and rehandle (return) stockpile. Scrapers will be more economical than dozers to replace overburden directly.
An applied expansion (swell) factor would vary from 1.15 to 1.20 if truck and excavators are used and/or 1.04 to 1.10 if scrapers are used. This has been assumed (based on Mindarie A(2) operations) when considering overburden removal and management requirements.
5.3.5 Mine pit details
5.3.5.1 Start-Up pit
For each of the project stages (as outlined on Figure 5.1), an initial excavation (“start-up pit” or box-cut ) will be required to locate mining equipment on top of the ore-body prior to the commencement of ore excavation. Starter pit operations will employ the specified equipment used for the normal mining operations. This will then be relocated as volumetric void becomes available in the mining sequence.
5.3.5.2 Operational pit
At any one point in time the operational pits associated with each of the stages will be approximately 1,800 to 2,100 m long x 200 m wide (not including the stockpile areas). The width of the workings has been determined based on resource definition drilling.
The operational pit will be developed to a maximum depth of 26 m but typically 5 m to 11 m deep. During previous mining operations the mine pit depth reached a maximum of 32 m. On the basis of experience gained through mining of the Mindarie A(2)and C strandlines, and mining in other parts of the Murray Basin, an overall 60o batter angle could be applied.
At commencement of the starter pit a full Pit Slope Stability Assessment will be performed by reconciling the initial design with the overall stability. The implications (if any) of overburden stockpiles adjacent to the open pit will also be analysed.
5.3.5.3 Operational footprint
The total width of the operational footprint (based on the profile as detailed in Figure 5.3 below) is estimated at approximately 400 m. This area is made up of the following:
open pit (140 m) overburden storage areas (two areas of 50 m width) subsoil storage areas (two areas of 25 m width) topsoil storage areas (two areas of 12 m width) access/haul road and pipelines (one road, 25 m wide and pipeline corridor 10 m wide).
The above is typical but all care and attention will be applied to ensure the above is reduced where possible thus reducing the area and volumes of stripping where applicable.
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Figure 5.3 Typical cross section of mining operations
5.3.6 Ore recovery
The proposed mining method is a dry ‘strip mining’ concept whereby landplanes strip the topsoil and subsoil separately ahead of the excavation works. Overburden is then moved by scraper fleet to the back of the pit in a staged operation such that half of the base of the pit is available for mining of ore and the other half used for the pushing of overburden from the front to the rear of the pit. Mining and process plant equipment move progressively along the strand (refer Figure 5.1, Appendix L). The base of the open cut would extend the full width of the ore body (approximately 140 m) with sloped sides as required for geotechnical stability (based on an overall slope of around 60°). Ore is separately excavated using a bulldozer to push it to the in-pit ore stockpile (for blending and grade control purposes) where it will be fed into the slurry unit with a front end loader (refer Figure 5.1, Appendix L).
The mining concept proposed for the Mindarie C project involves the following:
Removal of topsoil to a depth of 100–300 mm and subsoil to a depth of 200–300 mm from the total area of operations by landplanes (tractor scoops) and stockpiled on both sides of the pit to a height limit of 4 m and 10 m respectively (refer Figures 5.1–5.3, Appendix L).
When sufficient topsoil and subsoil has been removed to allow heavy earthmoving machinery to safely work in the adjacent areas, removal and storage of overburden by scrapers (truck/excavator) will commence. Overburden will be removed using scrapers.
A bulldozer will push the bulk of the ore onto an ore stockpile adjacent to the slurry unit. A front-end loader (excavator) located on top of the ore body loads the ore into a mobile slurry unit which screens the ore at 45/75 mm and mixes the extracted sand with water to form slurry which is pumped to the PCP (located adjacent to the Mindarie A(2) strandline) (refer Figure 5.1, Appendix L).
The oversize from the slurry unit will be returned to the void by front end loader.
Once the ore has been removed, the construction of the start-up tailings cell will commence (refer Figure 5.2, Appendix L). The start-up tailings cell (for storage of combined slimes and sand tails). This will allow the mining face to advance the required distance along the mine pit to allow the formation of the first tailings cell within the pit as shown in Figure 5.2 (Appendix L).
The slurry will be pumped to the PCP and screened again at 3 mm and then processed through a 2 stage de-sliming cyclone circuit and a six stage spiral to produce HMC.
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The de-sliming cyclones will send the fine slime to the thickener to thicken the slime to release water for re-use in the PCP and to slurry fresh ore.
Following processing and de-sliming the depleted sand and thickened slime (mostly clay) from the PCP is returned to the start-up tailings dam via slurry pipes until the mining face advances far enough to allow a wall to be built and the tailings from the PCP being re-directed into the tails cell in the pit (refer Figure 5.1, Appendix L).
After the mine face advances sufficiently where the second tailings cell wall is constructed, tailings from the PCP will be re-directed into that cell. Once the tailings in the start-up cell will start to be buried with overburden either from the advancing overburden face or from the overburden stockpiled material. This will continue with a series of cells following any void that the ore has been extracted.
5.3.7 Slurry unit
The slurry unit will be located at the floor of the open pit and is designed to receive, screen and slurry the ore to the PCP at an initial rate of 500 tonnes per hour at 50% solids (weight to water ratio; w/w). The slurry unit will be located in the open pit and travel along the mine pit as the mine advances. The nature of the proposed mining technique dictates that the unit will advance in 100–150 m increments along the top of the ore body with about three moves expected each month depending on the width and depth of the ore body at the time.
The unit will consist of a hopper which is loaded with ore by either a front end loader or an excavator. The discharge from the hopper will either go directly into the screening section of the slurry unit (to remove +45 mm oversize material) or onto a conveyor that feeds into the screening unit. The oversize material will be discharged from the end of the screening unit and returned to the pit void by front end loader. The unit will be diesel powered and used to power all the motors on the slurry unit.
Water for the slurry unit will be supplied from the PCP which will be pumped to the mining pit in a pipeline corridor on the side of the mining pit (refer to Figure 5.1, Appendix L).
The undersize material from the screen section will gravitate into a hopper, where additional water is added and pumped via a 315 mm OD diameter pipeline to the PCP. The PCP slurry supply pipeline will exit the pit via the same path as the incoming water in the pipeline corridor. The slurry and water pipelines will be bound together with quick release pipe connections in such a way that they can be readily disconnected and moved as a single skid type unit.
Booster stations will be located adjacent to the pit to assist with slurry pumping when the PCP is greater than 2 km from the mining area. These booster pumps will be controlled via telemetry which allows operators to control the pump speed from the control room.
During mining operations, it may be necessary to bring the slurry unit to the surface to enable the mining sequence to be re-established. The slurry unit will be mounted on skids and towed by a bulldozer as mining progresses through the pit. The slurry unit will be relocated every two weeks and will halt production for the duration of the move (approximately 2–4 hours). Pipe changeovers will be required for this process, the pipes will be inspected prior to recommencement of the slurry unit to reduce the likelihood of leakages occurring. Both slurry and water pipelines will be fitted with a flow meter and density meter to record and control the flow of material to the PCP.
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5.3.7.1 Tailings cells
Tailing cells will consist of a discharge point (where rheology modifiers will be injected into the discharge line – this may change and be injected at the PCP pending new developments with rheology modifiers. Slimes and sand tails are co-disposed into the tailings cell, supernatant water is then pumped via sump pump back to the PCP and or slurry unit. Both discharge and recovery water pipelines will run alongside the slurry unit pipelines (refer to Figure 5.1, Appendix L).
5.4 Processing
5.4.1 Primary concentrator plant
The PCP has been designed to initially treat a nominal 500 tonnes per hour (t/h) of ore or 3.7 Mt annually (85% run time, 7,446 hr/annum) at a heavy mineral feed grade of 2.59% heavy mineral and initially produce 120,000 t/annum HMC from initial rates of 3.5 to 4 Mt of mined ore per year.
The PCP is currently located on ML6220 (Mindarie A(2) strandline) within the project administration site (refer to Figure 5.6, Appendix L) and consists of a number of integrated modules that together process ore to produce HMC . The plant is semi-permanent but re- locatable and may be relocated to the eastern portion of Mindarie C (ML6226) if necessary.
The PCP complex comprises of the following units:
primary screening module primary and secondary cyclone module spiral separation module tailings pump module concentrate upgrading module electrical transformer/distributor module make-up water and return water module pond pump module thickener module flocculant make-up and storage module.
The slurry and process water pipelines will be located on ML 6226 as it is mined and cross into ML 6220 over a track between ML 6226 and ML 6220 (refer to Figure 1.2, Appendix L). It will then connect to the PCP located at the administration site. Negotiations with the landholder are currently being undertaken in order to continue utilising this track.
5.4.2 Process description
Water for the PCP and slurry unit is supplied from the process water tank which is supplemented by groundwater from production wells located on ML6220. The slurry arriving at the PCP will be screened at 3 mm. In the course of being pumped some agglomerated – 45 mm material will be broken down and only competent rock and stones will be removed at +3 mm. The oversize from the secondary PCP trommel will fall to the ground in a bunded area and be collected by a front end loader and then transported back into the open pit void.
The undersize material from the secondary PCP trommel will gravitate into a hopper and be pumped to a two stage cyclone circuit where the -45 µm material will be separated from
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the -3 mm + 45 µm. This fine (‘slime’) material is largely clay and some fine silt and is detrimental to the separation of heavy minerals and these flows into the thickener where it is thickened with the aid of flocculants. Flocculants are long chain polyacrylamide molecules which have free ions which bind the fine particles together.
The coarse fraction is then pumped to a number of spiral separation stages. The heavy mineral fraction is separated on the spiral concentrators using gravity as the means of separation. In most mineral sands operations one pass over a spiral is not sufficient to recover the heavy minerals and in some cases only two stages are required, but in this case six stages are required to recover 90% of the heavy minerals that contain an HM grade of 90%.
This HMC is pumped to a cyclone and the underflow is deposited onto the ground into a stockpile. The cyclone increases the solids content to 70% to allow the HMC to stack.
Over a number of days the HMC dries out to between 5 to 10% solids and then it is loaded into trucks and transported to Port Adelaide. Water from this draining process is collected via the drainage system and then pumped into the surge bin as it may contain some valuable heavy minerals.
The coarse sand and the thickener underflow are combined in a hopper in the PCP and pumped back to the open pit.
The most crucial part of the tailings pumping is the addition of flocculants to the tailing discharge to agglomerate the sand and slime to create a stable solid. This mixture then releases water which is pumped back into the circuit and then enables earthmoving equipment to place overburden on top of the dried tailings and quickly rehabilitate the mined areas. Tailings management is further discussed in Section 5.5 below.
The water released from the tailings is recycled and it is expected that between 50 and 70% of the water going to the tailings void will be recovered and re-used.
5.4.3 PCP components
5.4.3.1 Power supply
The total power requirement for the PCP facility is in the order of 1.5 MW per month.
A power module will supply all process modules located in the near vicinity of the PCP. The power module will house an 11 kV switchboard and a 415 V switchboard.
The power module will be supplied with power from the 11 kv line via overhead mains conductors. At both ends of the overhead mains conductors the last span will connect to a short section of trailing cable (<50 m) at termination poles. The trailing cable will then be terminated at the source end and Power Module 11 kV switchboards.
The 415 V switchboard is supplied from a 2,000 kVA transformer mounted on the module. The 415 V switchboard supplies only feeder loads.
The 11 kV and 415 V switchboards will be housed in containerised, independent, air- conditioned switch rooms.
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Both 11 kV and 415 V circuits supplying process modules will be connected via trailing cable and plugs to sockets on the power module.
Immediately after locating the switch room, but before applying power, the power module will need to be connected to electrical earth. This means that electrodes and/or a buried earth mat will need to be connected to power module main earth. Although it is likely to be uneconomic to recover the electrodes and/or a buried earth mat when relocating the power module, they will be removed to avoid future hazard to ongoing land use.
5.4.3.2 Instrumentation and control
All process modules will be provided with a local Programmable Logic Control (PLC) and a radio telemetry module. Once the individual process module is plugged into the power module, local and remote monitoring and control will be made available on that individual process module.
The PCP, process modules and mine modules can all be monitored from the SCADA computer in the PCP control room. Automatic start-up and shutdown sequences will be provided.
Equipment protection will be provided on the module relating to the equipment. As such, the integrity of the radio link will not be necessary to provide reliable equipment protection. Electric drive status monitoring, starting and stopping will be made available both locally and to a remote operator located at either SCADA terminals within the PCP control room. Pumps will incorporate pressure switch protection on the discharge line. Equipment that is not directly driven will be provided with under speed protection.
All sumps will have level control and modulating valves to control the sump levels automatically to prevent undue spillage.
A trench will be designed to recover any spillage and return it via a sump pump to the surge bin to prevent any escape of slurry to the surrounding area.The PCP control room located within the PCP will provide localized control over PCP, mine site and production well equipment.
5.4.3.3 PCP screening module
The PCP screening module will comprise of a tromel with 3 mm apertures mounted on a skid to enable relocation as required. The main components are the trommel, a surge bin and a primary cyclone pump unit. The total weight of this unit in non-operating condition will be approximately 50 tonnes.
Feed will be pumped from the mine at nominally 50% w/w solids density and the +3 mm fraction removed as oversize by the trommel screen.
The screen underflow bin will function principally to dilute the feed to the primary de-sliming cyclones to a density of around 30% w/w solids.
5.4.3.4 Primary and secondary cyclone module
The main components of the primary and secondary cyclone module will comprise a 7.0 m diameter surge bin, primary cyclone units, secondary cylclone units, primary cylone overflow bin, surge bin and a pump for each bin. The module will weigh approximately 70 tonnes and
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will be skid mounted to enable relocation as required. This module is provided with a 415 V electrical supply and requires approximately 180 kW.
A flow meter and density meter on the line from the surge bin to the spiral separators will measure these two parameters to enable flow rate, density and tonnes per hour to be dtermined. A mass flow and totalized mass flow will be calculated by the control system. In addition, a PID control loop will monitor the slurry line density and adjust a fine density control valve on the bin to achieve a stable feed density to the PCP and maintain a minimum flow to prevent bogging of the line.
5.4.3.5 Spiral separation module
There are 4 spiral seperation modules which include 6 sprial circuts comprising the following:
1. Roughers 96 starts of CPG MT HCI spirals 2. Tails scavenger 120 starts of GPG MT HCI spirals 3. Mids scavenger 296 starts of CPG MT MG4 Spirals 4. Cleaner 72 starts of CPG MT MG6.3 spirals 5. Re-cleaner 24 starts of CPG MTHG10 spirals 6. Recleaner scav 18 starts of CPG MT HG10 spirals.
The modules are mounted on skids so they can be relocated. The total non-operating weight of all the modules will be in the order of 220 tonnes.
5.4.3.6 Tailings pumping module
The tailings pumping module incorporates a 5 m mass flow bin and three transfer pump units. The pumps are KSB 150-500 which are driven by 220 kW 4 pole electric motors (or equivalent).The tailings bin is fitted with density control instrumentation similar to that described for the primary spiral surge bin.
The module weighs 48 tonnes and mounted on two separate skid bases.One of the pump drives are fitted with a variable frequency controller. This is arranged such that it can be switched over to control any one of the stage pumps. This provides optimum control over the tailings pump line whether the module is operating in single, double or three stage mode.
An 11 kVAC socket mounted on the power module will provide power to this module. A 2,000 kVA transformer and 415 V motor control centre is located on this module. The 415 V motor control centre will house drive switchgear and control. The power requirement for this module is nominally 600 kW.
A flow transmitter will report the real time volumetric flow of material being delivered from the tails bin. A nucleonic density transmitter will monitor the specific gravity of the slurry line from the tails bin. A mass flow and totalized mass flow will be calculated by the control system.
5.4.3.7 PCP process water
The existing process water dam will be regarded as a collection pit for run off rain water from around the site as it is the lowest point on the site. Also possible overflow from the thickener overflow tank will go into the process water dam. A pump will be located in this dam to pump water back into the system when the water is clear enough to do so.
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A process water tank will be provided adjacent to the existing process water dam (now only a stormwater collection pond) for storage of PCP process water. This will be constructed as required in order to minimise the potential for leaks to the surrounding environment.
5.4.3.8 Process water leak protection and monitoring
Monitoring surrounding the process tank and the stormwater collection pond will continue to occur. Prior to operation and in compliance with operating conditions background water monitoring was conducted in wells surrounding the site and subsequently 21 registered wells within a 10 km radius of the MZ project area (refer to Figure 5.4, Appendix L) were selected for routine ongoing monitoring. During 2010, 19 of these wells have been routinely monitored.
MZ is in compliance with groundwater monitoring requirements as listed in ML 6220 (Mindarie A(2) strandline) and ML 6226 (Mindarie C strandline) for wells within 10 km of the MZ project area as well as for the MZ production wells. During the 2010 reporting period the site was in care and maintenance, less than 15 megalitres of water was used.
5.4.3.9 Flocculant preparation
Magnafloc or a similar flocculant will be stored on site for use in the PCP. The flocculant will be an organic flocculating reagent that is used to agglomerate particles in the thickening stages of the concentration process. Flocculant will be transported to the PCP on formed roads with compacted road base. The material is non-toxic and biodegradable, such that the risk to the environment should spill occur is small.
The flocculant preparation for the rheology modifier proposed is based on a design flocculant powder dosage rate of 200 grams/tonne of total tailings. For a tailings feed rate of 430 t/h, the flocculant usage rate will be approximately 86 kg/h active powder and 17,200 L/hr of 0.5% dilute flocculant solution.
Flocculant batching plant
A suitable batching and storage plant is located in the PCP to enable convenient operator monitoring. The plant will be supplied complete with instrumentation and controls to enable automatic continuous batching and flocculant transfer to storage with the powder storage hopper requiring re-filling approximately once per week.
The flocculant batching and storage plant will include a bulk silo designed to receive powder grade flocculants, the flocculant is transferred pneumatically from the bulk unloading system into the silo and discharged through an outlet valve which is mounted directly above a powder metering unit.
Solid grade flocculant is fed from the powder silo via the constant rate, volumetric screw feeder into an air stream from a blower. Air conveys the flocculant via the "Jet Wet" dispersion head into the agitated mix tank. After complete dissolution the flocculant solution is pumped into a storage tank.
The bulk hopper is supplied complete with load cells, vibrator, dust filter, discharge valve and powder metering unit to suit the attached Auto Jet Wet Unit. The Powder Silo together with its dust filter ensures that the product is kept dry and free flowing to maintain a flooded head to the powder metering unit situated directly beneath its outlet.
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5.4.4 Hours of operation
The PCP will operate 24 hours per day, seven days per week.
5.5 Tailings
5.5.1 Tailings characterisation
The tailings will consist of coarse sand and slime that are combined in the hopper in the PCP and pumped back to the open pit. The slimes are defined as material less than 45µm in size and are fine silt and clay.
5.5.2 Tailings discharge
Rheology modifier a flocculant is added to the tailings stream as it enters the tailings void. It has to be injected in the correct ratios, at the correct dosing point and in the correct manner to ensure that the tailings are able to be rehabilitated in less than one month. The rheology modifier make up system will be located at the PCP for better control and dosing and additional instrumentation will be added in order to ensure that any breakdowns of the system are quickly identified. The tailings pipeline from the PCP and the rheology modifier pipeline will run with the main slurry pipeline in order to prevent any damage to the pipelines. The tailings pipeline route to the tailings cell needs to be well designed and maintained to allow pipeline extensions and retractions to be carried out by the day crew staff in an efficient and safe manner. The requirements will be determined by MZ staff and maintained by the earthmoving contractor.
The tailings pipelines will be bifurcated at the rear of the tailings cell and further bifurcated to provide at least four individual tailings placement pipes which will be regularly alternated to deposit the tailings across the tailings cell in the required manner as shown in Figure 5.5 below. The rheology modifier (flocculant) will be added to the tailings at the end of the pipeline to allow the slimes and sand tailings to form a homogenous material that dewaters rapidly.
Figure 5.5 Tailings deposition
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The tailings cell will be operated in a manner that allows the water draining from the tailings deposited naturally to drain to the sump at a low point in the tailings cell. The tailings pipelines require advancing in a sequence so that the front face of the tailings is always forming a batter towards sump as shown in Figure 5.5.
The full width of the tailings cell will be utilised at all times so that the maximum surface area for drainage and evaporation is presented.
An overflow pipe will be inserted in the wall during construction at a height that would come into operation when the tailings cell is almost full and the freed water allowed to overflow into the next tailings cell. The overall aim of this process is to promote and accelerate the separation of the water from the tailings and remove it from the area containing the tails. This will allow the overburden to be placed over the tailings in a timely manner to complete the rehabilitation as early as possible.
The uncontrolled filling of the tailings cell to the upper levels without dewatering will not be allowed to occur. There will be an interlock on the plant PLC that will start the shutdown sequence if the rheology modifier unit stops. In addition there will be an operational standing order that if the rheology modifier is not performing correctly, the mining process and separation in the PCP will be shut down until all systems are operating correctly.
5.5.3 Tailings management
Operational procedures for the tailings discharge include:
operating the water draining system to remove water from the top and base of the tailings cell when the water is clear of solids moving the active discharge locations daily to ensure even development of the tailings beaches discharging tailings at a velocity that is from an open unrestricted pipe(s) frequent monitoring and inspections (minimum one per production shift) of tailings discharge points, rheology modifier dosage unit, water level in the tailings cell and water return pipelines flow inspection of tailings at discharge to allow rapid detection of any potential tailings line breach pressure monitoring in tailings line additional instrumentation added to the rheology modifier make up system to ensure breakdowns are identified quickly appointment of a dedicated supervisor in charge of the rheology modifier make up system and flocculant for the thickener annual review of operational procedures.
5.5.4 Tailings associated components
The movement of tailings pipes will be with the assistance of smaller front end loaders with fork adapter.
The power supply for the tailings instrumentation and control will be by diesel engine or electricity powered mobile (skid) pump.
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5.6 Sequence of mining and rehabilitation operations
5.6.1 Mining direction
Mining of the Mindarie C strandline will commence approximately 2.8 km west of the previously mined (now rehabilitated) section of the strandline and progress southeast for approximately 2.6 km approaching the previously mined area. Mining will then restart immediately east of Loxton – Murray Bridge Road and progress southeast for approximately 5.5 km (refer Figure 1.2, Appendix L). Mining is planned to commence in the first half of 2012.
5.6.2 Mining sequence and scheduling
The expected sequence of operation for Mindarie C is shown diagrammatically in Figure 5.2 (Appendix L). For the overall Mindarie Mineral Sands Project the Mining Schedule is subject to change, as a result of the overall operational requirements and advancement rates, Normally this is adjusted on a quarterly basis. The mining schedule for the remaining strandlines will be determined based on the results of ore reserve studies, community consultation and other inputs.
5.6.3 Production schedules and annual production
The mining plan for the Mindarie Mineral Sands Project has a life of approximately 13 years. Mining of the Mindarie C strandline is expected to be completed within 25 months of commencement.
In practice the tonnage and grade will reflect operating performance and prevailing economic conditions being experienced at the time.
The PCP has been designed to initially treat a nominal 500 t/h of ore or 3.7 Mt annually (83% run time, 7,446 hr/yr) at a heavy mineral feed grade of 2.59% heavy mineral and initially produce 120,000 t/yr heavy mineral concentrate (HMC) from initial rates of 3,500,000 to 4,000,000 tonnes of mined ore per year. This will be upgraded to 90% HM grade.
5.7 Supporting mine infrastructure
5.7.1 Electricity
The Mindarie C site will be fed by the existing power infrastructure located on the Mindarie A(2) site. Power for the Mindarie A(2) operations is sourced via the Company’s overhead 66 kV transmission line from the Pyap/Loxton substation (which is owned and operated by ETSA Utilities).
During the Mindarie A(2) mining operations, a 66 kV overhead power line was installed from the Pyap/Loxton substation to the strandline. The power line generally follows secondary road verges along roads between Pyap and Mindarie.
The switch yard at Mindarie is located on the northern side of the MSP on the Mindarie A(2) site (refer Figure 5.6, Appendix L) and comprise a 66/11 kV transformer, circuit breakers,
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surge arrestors and overcurrent protection. Switching provides for an 11 kV feeder line to the existing PCP and 11 kV feed to the decommissioned MSP.
The PCP currently draws power from the 11 kV distribution line whilst all services between the PCP and mining area together with all slurrying and pumping services within the open pit will be diesel powered. PCP power requirements are estimated at 1.2 MW.
An underground 11 kV cable supplied the decommissioned MSP 11 kV switchboard. The switchboard supplies an 11,000/415 V, 2000 kVA transformer. In addition, a second 11 kV circuit connects to an overhead conductor and supplies the PCP, mine site and production wells.
The 11 kV and 415 V switchboards are housed in containerised, independent, air- conditioned switch rooms.
Emergency supply is provided for localized emergency building lighting and SCADA PC Uninterruptible Power Supplies (UPS). These emergency supplies will be designed to yield 15 minutes of backup power.
Power for operations on the Mindarie C strandline will be installed beneath the existing railway and highway in accordance with the safety standards of the owners. Installation of power and other utilities beneath this infrastructure has successfully been undertaken as part of the Mindarie A(2) operations.
5.7.2 Pipelines
5.7.2.1 Raw water supply
Raw water will be required on the Mindarie C operations to mix the dry excavated material (within the slurry unit) into slurry for pumping to the PCP.
Water for the operation of the slurry unit will be sourced from recycled water from the mining process and the current water wells located on the Mindarie A(2) strandline for which MZ has an authorisation to extract (refer to Section 5.9 and Figure 5.4, Appendix L).
The current authorisation permits the extraction of (on average) 4,292 ML per annum (and a maximum of 6,000 ML) and permits the use of the extracted water on the Mindarie C mining lease.
No additional water (above the current allocation) is required for the Mindarie C operations. As a result, it is not currently proposed to install any additional groundwater supply or monitoring wells as part of the initial operations on the Mindarie C strandline.
As with supply of power to the Mindarie C strandline, installation of water supply pipelines will occur under the railway and highway as required.
5.7.2.2 Slurry
Ore slurry from Mindarie C strandline will be pumped to the PCP which will (initially) remain in its current location on the Mindarie A(2) strandline.
The slurry pipeline from the PCP will be installed beneath the existing railway and highway in accordance with the safety standards of the owners once mining moves the eastern portion of the strandline.
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5.7.3 Ancillary infrastructure
5.7.3.1 Accommodation camp
An accommodation camp is likely to be constructed to support mine personnel during the course of mining of the Mindarie C strandline. Options for the accommodation village are currently being investigated.
The location of the accommodation camp is still under consideration, however MZ have identified two preferred options:
A site located within the Wanbi Country Township adjacent to Karoonda – Murray Bridge Road. This site is currently owned by the District Council of Karoonda East Murray. Services are not currently provided to the site, MZ will consult with the relevant Authorities and infrastructure service providers if this is determined to be the preferred site.
A homestead site located northeast of Wanbi within Wanbi Flats. This site is privately owned and was previously utilised as a research facility. Seven houses exist within this site and electricity, sewerage and water services are provided. Consultation with the landowner, relevant authorities and infrastructure service providers will be required in order to determine whether the services are appropriate.
The accommodation camp will house around 50 to 80 mining personnel and will be constructed to meet the requirements of the International Workers Accommodation Process and Standards. Figure 5.7 (Appendix L) outlines the indicative location of the two preferred accommodation camp options.
The appointed mining contractor will be responsible for the design and construction of the accommodation camp as well as the day to day management of the camp and site personnel.
Appropriate Development Approvals and Council consultation will be completed in order to gain development approval for the construction and operation of the accommodation camp in accordance with the requirements of the Development Act 1993.
5.7.3.2 Crib room
An elevated crib room for general purpose use, including meal breaks and sanitary requirements will be located adjacent to the main working areas on the Mindarie C strandline. As mining along the strand progresses, the elevated crib room will be relocated as required.
5.7.4 Fuel storage
Minimal fuel and chemical storage will be required on the Mindarie C strand line. Currently two 50,000 L diesel storage units exist within the MZ plant site (refer to Figure 5.6, Appendix L). Additional diesel storage will be located within self-bunded mobile tanks which will move along the Mindarie C strandline in accordance with the mining sequence.
Storage design and bunding requirements for an expected maximum of 190,000 L of diesel will be stored on the Mindarie C strandline in accordance with the SA EPA requirements (Bunding and Spill Management Guidelines 2007). Fuel will be delivered to the site in bulk as required.
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5.8 Road access and transport
Access to the western portion of the Mindarie C strandline will be gained from Knights Well Road. As operations along the strandline progress (as outlined on Figure 1.2 (Appendix L) and discussed in Section 5.3) access requirements will be reviewed and revised as necessary.
Following production of the HMC at the site of the former MSP Murray Zircon propose to transport the HMC to Port Adelaide using either B-Double trucks with side tipping capability or standard trucks. Each trailer is expected to have a capacity of 24 tonnes (48 tonnes total). This will be confirmed following the appointment of the Transport Logistics contractor. If B-Double trucks are used it is expected that 7-8 trucks per day would be needed and about 12 trucks per day for standard trucks.
As the HMC will be produced from slurry that will be pumped from the mine site to the PCP the HMC transport trucks will only need to access a small portion of Knights Well Road, then cross the railway line and join the approved B-Double route from Loxton to Murray Bridge and on to Port Adelaide. The proposed route is indicated in Figure 5.4 (Appendix L).
The section of Knights Well Road that will be used by trucks to enter and leave the former MSP site is not approved for B-Double truck use. MZ is making an application to the Department for Planning Transport and Infrastructure (DPTI) for approval to use this section of Knights Well Road. DPTI will determine the requirements for any upgrade of the road and safety provisions that MZ will need to adhere to.
In addition as Knights Well Road is under the control of the Council. MZ will need to develop and implement a traffic management and maintenance agreement with the Council. Discussions are being had with Council to finalise an agreement.
MZ are currently in consultation with a transport Contractor to confirm the trucking route, however it is expected that the transport of HMC will follow the following route (refer to Figure 5.8, Appendix L):
Loxton – Murray Bridge Road south to Tailem Bend Princess Highway Portrush Road Hampstead Road Grand Junction Road South Road Port River Expressway Victoria Road Coghlan Road (wharf entrance).
5.9 Water management
5.9.1 Water supply
Project water supply requirements during operations comprise:
Ore mining water – to slurry the ore in the pit which is pumped to the PCP for processing.
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Processing water – within the PCP water will be used as make up water when diluting certain streams, for making up flocculant slurry tailings and for general wash-down and housekeeping purposes. Tailings slurry – the tailings will be pumped from the PCP to the mine pit and subsequent tailings cell at solids concentration of approximately 50% by weight. Dust suppression and vehicle wash down water – water carts will operate along the mine pit void and stockpiles. Potable water for site amenities.
Water supply for the Mindarie C operations will be sourced from recycled water from the mining process and the current production wells located on site.
It is not currently proposed to install new water supply wells on the Mindarie C strandline. In the event that water supply bores are required on the Mindarie C strandline, an amendment to this PEPR will be submitted to DMITRE and the Department for Water outlining the location of the bores and associated groundwater monitoring (depth and quality).
Whilst the process water meets potable water guidelines it has a high salinity making it distasteful for people, thus in some crib rooms the water will first be put through a reverse osmosis unit to improve the taste. In addition bottled water is brought in for drinking.
The initial amount of water required for mining of the Mindarie C strandline is 1,816 ML/annum on average (where slimes are 12% in ore and a 500 tonne/hour processing rate), this includes the following breakdown:
1,727 ML/annum for the PCP (running approximately 7446 hours per year) 36 ML/annum treatment of dust on roads (equivalent to 2 l/second for 500 hours) 13 ML/annum for rehabilitation activities (e.g. watering) 40 ML/annum for topsoil dust suppression.
Figure 5.9 below indicates the water balance model for the use and reticulation of water and waste water on site.
This model is based on the following assumptions:
50% of the water entering the tails dam is recovered to be used to slurry fresh ore. The other 50% of water is contained in the dam, lost to evaporation and seepage into the surrounding ground. Only 50% of water is recovered (this is considered a conservative estimate and is likely to increase in practice). The water allowance is 6,000 ML/annum to a maximum of 42,920 ML over the 10 year allocation period.
The existing production wells will provide this water and consists of five wells; four operating and one spare with each well capable of delivering 90 m³/hr from a depth of 120 m. The well pumps are Grundfos SP95-13 with 55 kW motors fitted (or equivalent). Wells were installed nominally at 1,000 m intervals along the mining lease. Locations are given in Figure 5.4 (Appendix L).
Power is reticulated to each well location via an overhead power line with pole mounted transformers at each location.
The production delivery line is constructed from polyethylene (PE or “black poly”) pipe appropriately sized.
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Figure 5.9 Water balance estimate
Each production well has been test pumped to determine its safe yield and pump depth setting. One or two production wells at the strandline (depending on its length) will be test pumped to examine aquifer hydraulic characteristics. Individual wells in the area have yielded up to 50 L/s or more, but for design purposes a yield of 25 L/s has been assumed.
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All production wells in use are fitted with an integrating water meter to measure instantaneously and record cumulative water flow. Meters are read at weekly intervals from active wells and records kept to demonstrate that the authorised quantity of water has not been exceeded.
Charting during 2009 shows that when the production wells are in operation the drawdown on the water level is between 15–30 m and drawdown on the adjacent observation wells is 3–5 m. The two observations bores are located approximately 100 m from production wells MA (2)-2 and MSP-1 respectively. When the production wells are not in operation, standing water levels (SWL) recharges to its original levels (Australian Zircon 2009).
Two monitoring wells are installed with the central production well at the Mindarie A(2) strandline to allow pumping tests to determine aquifer characteristics. In general these are arranged perpendicular and parallel to the mining direction respectively. One of these monitoring wells is installed adjacent to the PCP and acts as an ongoing monitoring bore (Figure 5.4, Appendix L). At Mindarie A(2) well MSP-1 is test pumped to examine aquifer hydraulic characteristics.
For wells within 10 km of the project area, monitoring results indicate that there is no impact on aquifer levels.
The location of all monitoring wells within 10 km of the Mindarie A(2) project area are shown in Figure 5.4 (Appendix L).
The following parameters are measured for the production, observation and monitoring wells:
standing water levels pH total dissolved solids (TDS) electrical conductivity (mS/cm) uranium (U) thorium (Th).
5.9.2 Mine water and tailings decant
Mine water comprises pit-dewatering from groundwater inflows and incidental rainfall over the mine pit area. Mine water will drain to a sump at the base of the mine pit and be pumped to the slurry unit. Water collected from the tailings dams is pumped to either the slurry unit or to the process water tank.
5.9.3 Process water and tailings decant
The bulk of the water used at the PCP will be recovered using thickeners and recycled via the process water tank and be available for immediate re-use.
Any waste water arising from the mining service areas including vehicle washdown areas will be collected, passed through an oil-water separator and allowed to be collected and used as process water.
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5.9.4 Site run off/silt control and drainage
Given the generally low relief, low rainfall and high permeability of the soils in the area, excess surface water flows are virtually non-existent on site. However, due to clearing and other activities associated with the mining operations (e.g. stock piling of materials etc.) there remains a small risk of erosion and sedimentation occurring on site. Appropriate siting and implementation of temporary and permanent sediment control devices based on ‘catchment’ areas and topography will be installed. Sediment control used on site where necessary will include (but not be limited to):
sediment traps (straw bales, sand bags, logs and vegetation etc) sediment retention basins sediment control perimeter banks (earthen windrows, stacked logs and vegetation, stacked rock and geotextile and straw bales).
Erosion and sediment control measures will be applied/installed progressively or as needed as each stage of the Mindarie C strandline is opened up. The most important control structures measures will be installed first including diversion banks constructed as part of clearing and pit excavation operations. Sediment traps below areas to be disturbed will also be installed prior to clearing and grubbing if the slope and nature (e.g. sandy or clayey) warrants. Due to the generally flat nature of the landscape and highly absorbent sandy soils, sediment traps are not expected to be required for many situations.
Sediment control devices will be established around all areas prone to erosion, including stockpiles and any drainage lines. The length and steepness of slopes associated with mining operations will be minimised.
Strategically placed sumps will be excavated to collect all run-off from the access/haul road. Run-off from the PCP and HMC stockpile areas will be collected in drainage sumps constructed for this purpose and pumped back to the surge bin (refer to Figure 5.10 below).
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Figure 5.10 HMC stockpile drainage
Drainage of the overburden, topsoil and sub-soil stockpiles located along the length of the open pit during mining activities will be managed through contouring of the piles to divert all run-off away from the pit. Run-off will be drained toward a collection pond which will act as a sediment trap to reduce erosion of the surrounding land. Further information on stockpile management is included in Section 5.11.
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5.10 Waste and hazardous material management
Table 5.6 outlines the expected waste streams from the site operations.
Table 5.5 Expected management of the waste streams generated by Mindarie C project
Waste *Annual initial Characteristics Treatment/disposal quantity Overburden 19.9 million tonnes Predominantly fine to Replaced as backfill of medium sand mined area Slimes and sand 3.15 million tonnes Fine to medium sand and Replaced as backfill of tailings clay slimes mined areas Waste oils 75,000L Transported to off-site waste oil recycler Solid waste 62 tonnes Recycling or transported (packaging, food offsite to approved landfill scraps) Sewage Minor quantities High nutrient Collected for off-site concentrations and BOD treatment and disposal Construction Minor quantities Recycling or landfill materials *quantities are an estimate only.
5.10.1 Tailings/processing waste
Approximately 96% of the originally mined material will be returned to the pit as waste from the PCP once the heavy mineral component is removed from the ore. This material (sand tails and clay slimes) will be deposited into the mine pit and allowed to partly dry out prior to being covered by overburden, followed by subsoil and topsoil. This will occur as a staged process, where the waste will be returned as backfill from previously mined areas, still allowing access to in-situ materials.
Further details about the tailings are outlined in Section 5.5 above while post mining landform is discussed in Section 5.17 below.
5.10.2 Commercial and industrial waste
Solid waste generation on the Mindarie C strandline will be limited to:
solid waste (packaging, food scraps) associated with the operation of the crib room hazardous materials associated with mining activities construction materials associated with site establishment and relocation of the PCP.
Permanent waste storage facilities are located within the plant site providing separation for waste paper, plastics, hydrocarbons and glass (refer to Figure 5.6, Appendix L). Management of solid waste on site will be based on the waste hierarchy of control (i.e. avoid, reduce, reuse, recycle, recover then dispose).Following collection and storage for reuse and/or recycling, inert waste will be disposed off-site.
As mentioned in Section 5.7.2.2 reverse osmosis units are provided in crib rooms in order to desalinize water for potable use. The reverse osmosis units are small domestic units fitted to
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a tap in the sink of the crib rooms. When the membrane becomes clogged this is removed and hand washed. The amount released is minimal.
Hazardous materials require specific transport, storage, handling and disposal procedures that comply with legislative requirements and specific material safety data sheets (MSDS). Fuel and other hazardous wastes will be stored in drums and tanks with impervious bunds to contain spillages and will be disposed of periodically by a registered contractor.
The existing sewer system for the site will continue to be used. All sewage gravitates to an underground tank which is decomposed by anaerobic means and this main tank is located east of the laboratory (refer to Figure 5.6, Appendix L). The cleaned water is then pumped into the fields located adjacent to the plant site. Anaerobic decomposition is also used for the mobile crib rooms. The tanks are located on the skids adjacent to the crib rooms.
5.11 Stockpiles management
5.11.1 Topsoil and subsoil
As part of the operations undertaken on the Mindarie A(2) strandline, the project has developed a Surface Soil Dig Procedure and Surface Soil Dig Permit. This procedure and associated permit provides instructions on the excavation and placement of topsoil and subsoil. The procedure requires personnel who supervise an excavation or operate excavation machinery to complete and implement an approved Surface Soil Dig Permit.
Both the procedure and permit requirements will be implemented during operations on the Mindarie C strandline. The implementation of the procedure and permit will assist with rehabilitation and closure activities post mining.
The procedure includes the determination of the depth and characteristics of topsoil and subsoil by sampling soil profiles and/or undertaking an ElectroMagnetic (EM) Survey prior to removal of the topsoil and subsoil along the strandline (including the recommendations made in Maschmedt and Hignett 2003). Sediment and erosion control structures will be constructed prior to commencement of soil stripping and excavation activities, if required.
Stockpile locations will avoid working areas, areas of natural drainage and on site traffic routes and where possible the stockpiles will be placed as close to its re-use site as possible.
Soil from agricultural areas will be kept separately from soil from native vegetation areas and erosion control measures will be implemented to protect stockpiles and minimise erosion and sediment loss.
Indicative locations of stockpiles during mining operations on Mindarie C are shown on Figure 5.11 (Appendix L).
Stockpile locations have been designed to facilitate the shortest practicable haul distance when removal is taking place and minimise vegetation clearance.
5.11.1.1 Topsoil
Topsoil will be stripped using landplanes (tractor scoops) and placed on a stockpile on the side of the pit based on characteristics such as sand, sandy clay and clay and appropriately mapped and documented for management and rehabilitation purposes.
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Topsoil stockpiles would not be capped with clay to prevent wind erosion as done previously but rather have 1:4 (V:H) batters allowing a cover crop seeding to take place. Immediately after seeding a water cart will be used to provide a crust and moisture to seedlings.
Restriction on topsoil stockpile height would be applied making these stockpiles no higher than 3-4 m (refer to Figure 5.3 in Section 5.3.5).
5.11.1.2 Subsoil
Subsoil will be stripped as per the same methodology as the top-soil. As subsoils are more structurally sound, sub-soil stockpiles with batters resembling the natural angle of repose (23-28 degrees) will be developed.
In order to minimise land disturbances sub-soil stockpiles will be built up to a maximum height of 10 m as this occupies a smaller footprint (refer to Figure 5.3 in Section 5.3.5).
No surface treatment of subsoil stockpiles will be implemented other than ensuring a V-drain is placed in the centre of the stockpile allowing drainage lengthwise rather than cross-ways. Windrows would also be placed on the edges at completion.
5.11.2 Overburden
As required by the Mining Lease conditions, permanent overburden stockpiles created by the operations will be shaped to conform to the local Mallee landscape.
Overburden placement and reuse options are also considered, while minimising distances between the “start” and “end” points is preferred (in order to increase potential use of overburden to minimise depressions) it is not considered economically viable to move overburden excessive distances (e.g. over 100 m) in order to facilitate this. Soil horizons will be replaced in the same order that they were removed, i.e. fill the mining pit with overburden and cover with stockpiled subsoil horizon(s) where separately stripped, then cover with stockpiled topsoil. Soil will be reused as close as practicable to its point of origin.
Sediment and erosion control structures will be placed prior to commencement of overburden stripping and excavation activities, if required.
Overburden stockpiles will not exceed a height of 15 m (refer to Figures 5.1 in Appendix L and Figure 5.3 in Section 5.3.5). Further information regarding overburden stockpiles is included in Section 5.3.3.
5.11.3 Heavy mineral concentrate
The HMC stockpile area consists of a stacking pad which is sloped towards a trench down one side of the pad and the trench drains into a sump at the lowest point of the pad. The hardstand for the HMC stockpile area will be made from compacted earthfill and aggregate.
Three stockpiles will be produced to a height of approximately 5 m. Each of the three stockpiles will be approximately 314 m2 containing a volume of 524 m3 of material, for an overall capacity of 1,153 tonnes.
Each of the three stockpiles within the HMC stockpile pad will have a three sided bund wall made of 0.5m high X 0.5m deep by 1m long aerated concrete block in three or four layers to
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prevent excess wind erosion. In addition fine mist water sprayers will be distributed over the stockpiles to prevent the HMC being blown onto adjoining land.
A permanent spindle type centrifugal pump is placed in the sump and pumps this drainage water to the PCP. The sump will have a level control device that starts the pump when the sump becomes full and then switches off when the sump becomes empty. In addition there will be agitation water to the suction of the pump to clear out solids before pumping is started.
The HMC stockpile area will be approximately 80 m long and 30 m wide and provides for the storage of 30 days of product which will have an estimated total capacity of 10,000 tonnes. The layout allows time for the HMC to dry by gravity and drainage to 4–5% moisture. Three individual cyclone stackers will be also be constructed in the stockpile area.
The HMC stockpile will be located in the area utilised during previous mining operations, opposite the PCP (refer to Figure 5.6, Appendix L). This area will be designed to allow for loading of HMC into trucks to be transported to Port Adelaide.
Figure 5.10 shows the general layout of the HMC stockpile area.
5.12 Construction
5.12.1 PCP relocation works
As mentioned in Section 5.4, the PCP has been designed as a number of integrated demountable modules each arranged to be readily disconnected from each other when it will require relocation for future mining operations. The PCP may be relocated to the eastern portion of the Mindarie C strandline for mining operations to be undertaken along Mindarie C East as well as other adjacent strandlines. However, the requirement for moving the PCP for mining of Mindarie C East has not been determined, additionally, the PCP may be relocated onto a different Mining Lease if considered more suitable for future operations.
If it is deemed necessary to move the PCP for mining of the eastern portion of the Mindarie C strandline, MZ will consider environmental impacts associated with the proposed movement procedure and seek an amendment to this PEPR from DMITRE.
5.12.2 Access
As operations along the strandline progress (as outlined on Figure 1.2 (Appendix L) and discussed in Section 5.3.6) access requirements will be reviewed and revised as necessary. An access road will be constructed along the length of the strandline for access.
5.12.3 Accommodation
As outlined in Section 5.7.3 during construction workers accommodation will likely be required in Wanbi. Negotiations with landowners and infrastructure providers are currently underway.
Alternatively construction workers may be housed in commercial accommodation within neighbouring towns and transported to and from the site.
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5.13 Modes and hours of operation
Mining on the Mindarie C strandline will be undertaken 24 hours a day/7 days per week (on a rotational roster). The PCP will be operated 85% of this time equating to approximately 310 days per year.
5.14 Visual screening and site security
The overburden stockpiles will provide screening of the operational pit from the adjacent landholders. Mining operations are transient and rehabilitation of the open pit mine will occur progressively. The presence of vegetation along major roadways will provide visual screening from some of the mining operations for road users.
Since the mine site is mobile, traditional security measures are not feasible. However, there are existing perimeter fences around all areas proposed for mining i.e. farm fences. The site will be occupied 24 hours per day and all visitors to the mine site will have to be accompanied by a company employee or authorised contractor at all times.
5.15 Plant and machinery requirements
During operations, a variety of equipment will be used. Equipment required for operations generally comprise mining equipment, site mobile equipment (refer Table 5.6) and the PCP and slurry unit components such as screens, hydrocyclones, screens, floculant tank and filters.
Table 5.6 Site mobile equipment
Description Number Bulldozers 3–4 Front end loaders 1-2 Scrapers 6 Graders 1–2 Excavators 2 Dump trucks (100 tonne) 10 Service vehicles 2 Fuel truck 1 Water trucks 1 Delivery vehicles 3 4WD vehicles 12
Table 5.7 below outlines noise, vibration and exhaust outputs as well as the ignition sources for each of the site mobile equipment to be used during mining operations.
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Table 5.7 Mobile equipment output information
Type Size Capacity No. of Noise Engine Fuel Exhaust Ignition Units (litres) Output Source (litres/hr) Scrapers 657G/F 24.5 LCM 6 115dBA at ACERT C18 1597 79.85 Exhaust 25 m Dozers D10 N/A 4 115dBA at C32 ACERT 1987 99.35 Exhaust 25 m Dozers D8 N/A 2 115dBA at 3406CTA 625 31.25 Exhaust 25 m Dozers D7 N/A 1 115dBA at 3176SCAC 481 24.05 Exhaust 25 m FEL 980G 5.7 LCM 2 N/A C15ATACC 479 23.95 Exhaust C Grader 16G N/A 2 N/A C13 ACERT 511 25.55 Exhaust VHP B-Double N/A 48 tonnes 7 <69dBA - 310 - Exhaust *All CAT exhausts have a spark dissipation chamber in the exhaust system.
5.16 Resource inputs
5.16.1 Workforce details
The operations workforce will vary during the project mine life depending on the level of mining activity. Where possible, employees will be recruited from South Australia but additional recruitment from the rest of Australia may be necessary.
Personnel requirements during operations will be approximately 100 people including 40–70 personnel anticipated to be engaged by the mining contractor. These are summarised in Table 5.8.
Table 5.8 Operations workforce
Position Number Administration General Manager 1 Environment, Health & Safety Manager 1 Environmental Officer 1 Safety Officer 1 Administration Manager 1 Administration Assistant 1 Mining Mine Manager 1 Pit Supervisor/Technician 2 Surveyor 1 Geology Senior Geologist 1 Processing Plant Production Manager 1
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Position Number Operator 3 (per shift) Maintenance Maintenance Manager 1 Electrician 2 Fitters 2 Boilermaker 1 Mining Contractor’s Workforce Project Manager 1 Site Engineer 1 Safety/Training Officer 1 Production Supervisor 3 (1 per shift) Mobile Plant Operators 20-30 (per shift)
5.16.2 Energy sources
The project will operate 24 hours per day, 7 days per week. The average electrical power load during operations is estimated to be 18,000 MWh annually (refer Table 5.9).
Table 5.9 Estimated annual power consumption
Component Installed power Utilisation (%) Average MWh (MWh) consumed annually PCP (comprising the slurry unit, HMC 1,400 85 handling, tailings pumping and water pumping) Buildings and mining services 100 100 Total 1,685
It is estimated that the mining and processing of the Mindarie C strandline will produce
approximately 29,872 tonnes of CO2-e greenhouse gas emissions annually.
MZ does not currently plan on providing carbon offsets for energy usage, however, the applicability of green diesel fuel use is being investigated. MZ has committed to reporting greenhouse gas emission to the National Greenhouse and Energy Register (NGER).
5.17 Water sources
Water sources for the project are discussed in Section 5.9.
5.18 Mine completion and rehabilitation
Below is a summary of mine closure and rehabilitation activities. Further details are provided in the Mine Closure and Rehabilitation Plan (Section 8).
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5.18.1 Management of overburden
Figures 5.1 and 5.2 (Appendix L) indicate that overburden mounds will be created adjacent to the open pit and that backfilling will be progressive as the mining continues to ensure that overburden material does not have to be transported significant distances during rehabilitation.
5.18.2 Areas along the strandline
With the post mining landforms along the mined strandline it is possible that (following overburden, subsoil and topsoil replacement) the central elevation may be up to 2 m high along the centreline of the deposit which will provide a slope of approximately 1:19 (based on the design of the pit to be on average 200 m wide. A slope of this degree is considered compatible with the surrounding landform and will allow for crop cultivation.
5.18.3 Rehabilitation
Rehabilitation of the post mining areas will be undertaken to ensure that the land is rehabilitated to that of the pre-mining land use. Current land use along the Mindarie C strandline is broad acre farming (cropping). Remnant native vegetation also occurs in isolated pockets and transport corridors.
Rehabilitation activities will be progressively undertaken during operations at a rate similar to that of the mining process and following the completion of mining activities and removal of infrastructure/services.
5.18.3.1 Cropping land
Revegetation activities on cropping land will be undertaken in accordance with the landowner/leaseholder agreements established as part of the project.
A summary of the rehabilitation process for cropping land is provided below:
reshape land to a similar pre-mining landscape (including appropriate overburden, subsoil and topsoil replacement) reshaped landform to be stable, adequately drained and suitable for cropping replanting with appropriate cover crop monitoring of regrowth.
5.18.3.2 Native vegetation/mallee ecosystem
The rehabilitation of native vegetation/mallee ecosystem will be as follows:
identification of species in the area (this occurs prior to vegetation clearance) collection of seeds, other propagules and surface vegetative matter reshape land to a similar pre-mining landscape (including appropriate overburden, subsoil and soil replacement) reshaped landform to be stable, adequately drained and suitable for cropping respreading of stockpiles vegetative matter reseeding/tubestock planting exclusion of grazing monitoring of regrowth
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follow up actions as required (based on outcomes/recommendations from regrowth monitoring).
5.19 Mindarie A(2) and former Mindarie C rehabilitation
Rehabilitation activities associated with the previous mining of Mindarie A(2) and C strandlines are currently being undertaken.
Within the Mindarie A(2) strandline four locations are still to be rehabilitated (refer to Figure 4.10, Appendix L). The total area of the Mindarie A(2) lease is approximately 639 ha. As of November 2011, 80% of all overburden in this area (approximately 511 ha) had been reinstated. MZ anticipates that 95% (approximately 608 ha) of all overburden in the Mindarie A(2) strandline will be reinstated by December 2011. The remaining 5% include wet voids (areas which are too wet to place overburden upon) which are anticipated to be rehabilitated in early 2012 subject to climatic conditions (Murray Zircon 2011). Subsoil replacement has commenced and is expected to be completed by late January, 2012. This will allow all top-soils to be placed in time for the 2012 cropping season (i.e. late March to early April for cereal crops and late March to August for cover crops).
Rehabilitation work on the disturbed areas of Mindarie C strandline commenced in February 2010 and involved replacement of overburden, subsoil and topsoil. Further rehabilitation work was undertaken in August 2011, the work involving contouring and drainage design was completed in two days. The placement of subsoil was completed in October 2011 and topsoil will be replaced in early 2012. Seeding will occur in May 2012 and monitoring will occur on an ongoing basis after completion of rehabilitation (Murray Zircon 2011).
5.19.1 Planned rehabilitation works
Table 5.10 outlines the rehabilitation measures undertaken to date, measures proposed to be undertaken, and the timing for remaining work. Current rehabilitation areas are shown in Figure 4.12 (Appendix L).
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Table 5.10 Rehabilitation strategy and schedule from mid 2011 to early 2012
Area Task Detail Timing Strand 1 The overburden rehabilitation has been completed in Mid January 2012 A(2) West the western and eastern ends surrounding the wet void. (Area 1) The void has been reduced in size by roughly 50%. These areas have been grader-boarded and are ready for subsoil replacement. The use of a dump truck and excavator were used to attempt to reduce the volume of the slimes in the void. The wet slimes were transported to the eastern area of Area 1 for drying. This method was not efficient as the slimes were too wet and would have required considerable amount of resources to reduce the void. However, the method of solar drying successfully dried the slimes. Earthworks in Area 1 will resume when all other areas have been complete. 1b Subsoil replacement End January 2012 1c Topsoil replacement March 2012 1d Seeding April 2012 1e Monitoring Ongoing post- reaping Strand 2 The overburden rehabilitation is completed in the areas Late A(2) West surrounding the wet void. The void has been reduced in December 2011 (Area 2- size by roughly 75%. The subsoil and topsoil stockpiles backfill were relocated using landplanes so as to have access dam) to overburden underneath. This overburden was stockpiled and is ready to be pushed into the void to close it off. 2a Subsoil and topsoil replacement Early February 2012 2b Seeding April/May 2012 2c Monitoring Ongoing post- reaping Mindarie C 3 Contouring of land and drainage using D7. Completed on (Area 3) 03/08/11 3a Subsoil replacement. This item has been completed Completed on 15/11/11 3b Topsoil replacement March 2012 3c Seeding April/May 2012 3d Monitoring Ongoing post- reaping Strand 4 The deep wet void has been completely buried Mid October 2011 A(2) East displacing wet material into five (5) solar drying cells Final cover (Area 4) contained by windrows. The D7 has traversed through (January 2012) some of the cells to break to dried crust on top of the wet slimes to allow for further drying. Contouring of the surrounding area is completed. It is anticipated that drying process will take effect in January-2012 when final covering will take place. 4a Subsoil replacement January 2012 4b Topsoil replacement Early February 2012 4c Seeding April/May 2012
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Area Task Detail Timing 4d Monitoring Ongoing post- reaping Strand 5 The four dozers on-site have been working in this area Mid A(2) East since late October starting at the far eastern end. The December 2011 (Area 5) wet void was bridged in the middle to make the task of closing the voids more manageable. Overburden stockpiles surround the voids ready to be pushed in. The remainder of Area 5 has been contoured and some voids in the middle have been filled with the excess overburden. Subsoil replacement within the eastern end commenced on 15/11/11, with five stockpiles identified for the task. 5a Subsoil replacement. This item commenced on Mid 15/11/11 December 2011 5b Topsoil replacement February 2012 5c Seeding April/May 2012 5d Monitoring Ongoing post- reaping PCP dam 6a This area is complete. Dozers covered the PCP dam Completed on (Area 6) and hole left by ilmenite. Two metres cover has been 1/11/11 allowed. Contouring and drainage works have been complete. A(2) 6b Most of the ilmenite has been removed and placed in October 2012 Tailings the void of Area 3, which has since been closed over. and MSP To complete the rehabilitation and remove the rejects radioactive minerals a new void is required and this will dam become available when Mindarie C West is mined. (Area 6) Seek approval to ensure MSP dam is complete before Mindarie C East is mined Wet voids 7 Murray Zircon is trialling a variety of methods to Early 2012 (and determine the most effective rehabilitation process. ongoing) One of the processes to be tested is to replace wet void material with dry overburden material and allow wet void to dry and place it back with additional dry material. Recent works has indicated that solar drying and mechanical methods (use of dozers) are the better options in dealing with the wet voids. 7a Rehabilitation of wet areas. 2012 NOTE: The above schedule is based on 4 dozers (D7, D8, D9 & D10) currently present on site and including the five landplanes on-site. The schedule is also strongly dependent on weather conditions (solar drying) principally excess rainfall.
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