Idea Transcript
30
Elimatta Project Environmental Management Plan
Prepared for:
Taroom Coal Pty Ltd April 2014
Document History and Status Issue
Rev.
Issued To
Qty
Date
1
0
Taroom Coal Pty Ltd
1
3/3/12
2
0
Taroom Coal Pty Ltd
1
20/11/12
3 4
0 0
Taroom Coal Pty Ltd Taroom Coal Pty Ltd
1 1
16/04/14 24/04/14
Project Manager: Name of Client : Name of Project: Title of Document: Document Version:
Reviewed Gareth Bramston Gareth Bramston AGP AGP
Approved Andrew Pearce Andrew Pearce DM DM
Gareth Bramston Taroom Coal Pty Ltd Elimatta Project Environmental Management Plan Final
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TABLE OF CONTENTS 1.0
INTRODUCTION .......................................................................................... 5-1
1.1
THE ELIMATTA PROJECT ................................................................................................ 5-5
1.2
PROJECT LOCATION ....................................................................................................... 5-6
1.3
DESCRIPTION OF MINING TENURES ............................................................................. 5-9
1.4
RELEVANT STAKEHOLDER CONSULTATION............................................................. 5-10
1.5
REAL PROPERTY DESCRIPTIONS ............................................................................... 5-11
1.6
RELEVANT CODES OF ENVIRONMENTAL COMPLIANCE ......................................... 5-12
1.7
WILD RIVERS LEGISLATION ......................................................................................... 5-12
1.8
STATE DEVELOPMENT & PUBLIC WORKS ORGANISATION ACT 1971 .................. 5-13
2.0
PROJECT DESCRIPTION ......................................................................... 5-15
2.1
GENERAL OVERVIEW .................................................................................................... 5-15
2.2
PROJECT LIFE AND MINE SEQUENCE ........................................................................ 5-17
2.3
EXPLORATION ................................................................................................................ 5-19
2.4
MINING ............................................................................................................................. 5-19
2.5
SPOIL DUMPING ............................................................................................................. 5-30
2.6
PROCESSING ACTIVITIES ............................................................................................. 5-30
2.7
PRODUCT HANDLING .................................................................................................... 5-33
2.8
CHPP REJECTS ............................................................................................................... 5-33
2.8.1
Coarse Rejects ............................................................................................................. 5-33
2.8.2
Tailings (Fine Rejects) .................................................................................................. 5-33
2.8.3
Tailings Characterisation .............................................................................................. 5-34
2.8.3.1
Physical properties of Tailings ........................................................................................... 5-34
2.8.3.2
Chemical Properties of Tailings ......................................................................................... 5-34
2.8.4
Tailings Storage Facility Design ................................................................................... 5-35
2.8.4.1
Surface TSFs (TDN and TDNA) ........................................................................................ 5-36
2.8.4.2
In-Pit TSF (TDP) ............................................................................................................... 5-36
2.9
SURFACE WATER DIVERSION ...................................................................................... 5-37
2.9.1
Horse Creek Diversion .................................................................................................. 5-37
2.9.1.1
2.9.2 2.10
Diversion Stages ............................................................................................................... 5-38
Revegetation ................................................................................................................. 5-41 WATER REQUIREMENTS AND SUPPLY ....................................................................... 5-41
2.10.1 Water Usage ................................................................................................................. 5-41 2.10.1.1
Construction Water Usage ................................................................................................ 5-41
2.10.1.2
Operational Water Usage .................................................................................................. 5-41
2.10.1.3
Dust Suppression Water Usage ........................................................................................ 5-43
2.10.1.4
Overall Water Usage ......................................................................................................... 5-44
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2.10.2 Water Supply ................................................................................................................ 5-46 2.11
WATER STORAGE .......................................................................................................... 5-46
2.12
WATER DISCHARGE ...................................................................................................... 5-63
2.12.1 No / Low Flow Release Trigger .................................................................................... 5-63 2.12.2 Medium Flow Release Trigger ...................................................................................... 5-63 2.12.3 High Flow Release Trigger ........................................................................................... 5-64 2.13
SITE WATER MANAGEMENT ......................................................................................... 5-64
2.13.1 Water Management Strategy ........................................................................................ 5-64 2.13.1.1
Water Management Strategies over the Southern MLA 50254 ......................................... 5-65
2.13.1.2
Water Management Strategy over the Northern MLAs 50270 and 50271 ......................... 5-66
2.13.1.3
Expected Approval Requirements ..................................................................................... 5-66
2.13.2 Stormwater drainage .................................................................................................... 5-67 2.13.2.1
2.14
Operational Stormwater Infrastructure .............................................................................. 5-67
RAIL & SERVICES CORRIDOR WATER MANAGEMENT ............................................. 5-73
2.14.1 Major Crossings ............................................................................................................ 5-73 2.14.2 Minor Crossings ............................................................................................................ 5-74 2.15
ROAD DIVERSION AND CONSTRUCTION .................................................................... 5-75
2.15.1 Mine Roads ................................................................................................................... 5-76 2.15.2 Public Roads ................................................................................................................. 5-76
2.16
2.15.2.1
Mining Lease Areas .......................................................................................................... 5-76
2.15.2.2
Rail and Services Corridor ................................................................................................ 5-77
POWER SUPPLY ............................................................................................................. 5-79
2.16.1 Construction Power Demand ........................................................................................ 5-79 2.16.2 Operations Power Demand .......................................................................................... 5-79 2.16.3 Grid Connection Infrastructure...................................................................................... 5-80 2.17
FUEL AND HYDROCARBON STORAGE ....................................................................... 5-82
2.18
ACCOMMODATION VILLAGE ........................................................................................ 5-83
2.19
WORKSHOPS AND OFFICES ......................................................................................... 5-83
2.20
SEWERAGE TREATMENT .............................................................................................. 5-84
2.21
RUBBISH DISPOSAL ...................................................................................................... 5-85
2.21.1 Construction Material .................................................................................................... 5-85 2.22
ENVIRONMENTALLY RELEVANT ACTIVITIES ............................................................. 5-86
2.23
REHABILITATION AND DECOMISSIONING .................................................................. 5-87
2.23.1 Rehabilitation Hierarchy................................................................................................ 5-87 2.23.2 Rehabilitation Goals ...................................................................................................... 5-88 2.23.3 Mine Domain Objectives ............................................................................................... 5-89 2.23.4 Rehabilitation Indicators ............................................................................................... 5-89 2.23.5 Completion Criteria ....................................................................................................... 5-89 2.23.6 Progressive Rehabilitation Strategy.............................................................................. 5-98
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2.23.7 Post Mining Land Use ................................................................................................... 5-99 2.23.8 Soil Management .......................................................................................................... 5-99 2.23.9 Final Rehabilitated Landform of the Elimatta Project ................................................. 5-100 2.23.10 Rehabilitation Methodology ........................................................................................ 5-103 2.23.10.1
Contouring .................................................................................................................. 5-103
2.23.10.2
Ripping ....................................................................................................................... 5-103
2.23.10.3
Topsoil Spreading ...................................................................................................... 5-103
2.23.10.4
Revegetation .............................................................................................................. 5-103
2.23.11 Domain Specific Rehabilitation Techniques ............................................................... 5-104 2.23.11.1
Final Voids.................................................................................................................. 5-104
2.23.11.2
Exploration Areas ....................................................................................................... 5-106
2.23.11.3
Infrastructure Areas .................................................................................................... 5-106
2.23.11.4
Waste Disposal .......................................................................................................... 5-107
2.23.11.5
Water Dams ............................................................................................................... 5-110
2.23.11.6
Diversions................................................................................................................... 5-110
2.23.12 Rehabilitation Monitoring ............................................................................................ 5-112 2.23.13 Rehabilitation Maintenance ........................................................................................ 5-113
3.0 ENVIRONMENTAL VALUES, IMPACTS, CONTROL STRATEGIES AND PROPOSED EA CONDITIONS ........................................................................... 5-114 3.1
GENERAL ENVRONMENTAL DUTY OF CARE ........................................................... 5-115
3.1.1 3.2
General EA Conditions ............................................................................................... 5-115 AIR .................................................................................................................................. 5-117
3.2.1
Description of Environment ......................................................................................... 5-117
3.2.1.1
Sensitive Receptors ........................................................................................................ 5-117
3.2.1.2
Dust Concentrations ........................................................................................................ 5-118
3.2.1.3
Dust Deposition ............................................................................................................... 5-119
3.2.1.4
Gaseous Pollutants ......................................................................................................... 5-119
3.2.1.5
Meteorology Simulation ................................................................................................... 5-120
3.2.2
Environmental Value ................................................................................................... 5-120
3.2.3
Assessment of Impacts on the Environmental Values ............................................... 5-121
3.2.3.1
Potential Impacts ............................................................................................................. 5-121
3.2.3.2
Assessment Methodology ............................................................................................... 5-122
3.2.3.3
Air Quality Criteria ........................................................................................................... 5-122
3.2.3.4
Modelled Air Quality Impacts........................................................................................... 5-123
3.2.3.5
Air Quality Assessment Conclusions ............................................................................... 5-125
3.2.3.6
GHG Assessment ........................................................................................................... 5-126
3.2.4
Proposed Environmental Protection Objective ........................................................... 5-127
3.2.5
Control Strategies ....................................................................................................... 5-128
3.2.5.1
Air Quality........................................................................................................................ 5-128
3.2.5.2
Greenhouse Gas ............................................................................................................. 5-129
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Proposed EA Conditions using Measurable Indicators and Standards ...................... 5-130
3.2.6 3.3
WATER ........................................................................................................................... 5-130
3.3.1
Description of Environment ......................................................................................... 5-130
3.3.1.1
Surface Water Courses ................................................................................................... 5-130
3.3.1.2
Surface Water Quality ..................................................................................................... 5-136
3.3.1.3
Flooding .......................................................................................................................... 5-143
3.3.1.4
Groundwater Aquifers ..................................................................................................... 5-147
3.3.1.5
Groundwater Quality ....................................................................................................... 5-148
3.3.1.6
Aquatic and Groundwater Dependent Ecosystems ......................................................... 5-149
3.3.2
Environmental Values ................................................................................................. 5-149
3.3.3
Assessment of Impacts on the Environmental Values ............................................... 5-151
3.3.3.1
Potential Impacts on Surface Water ................................................................................ 5-151
3.3.3.2
Surface Water Quality Modelling ..................................................................................... 5-153
3.3.3.3
Surface Water Quantity Modelling ................................................................................... 5-153
3.3.3.4
Surface Water Flood Impact Modelling ........................................................................... 5-154
3.3.3.5
Potential Impacts on Groundwater .................................................................................. 5-160
3.3.3.6
Mine Dewatering Impacts ................................................................................................ 5-160
3.3.3.7
Groundwater Quality Impacts .......................................................................................... 5-161
3.3.3.8
West Surat Link Groundwater Impacts ............................................................................ 5-161
3.3.4
Proposed Environmental Protection Objective ........................................................... 5-162
3.3.5
Control Strategies ....................................................................................................... 5-162
3.3.5.1
Surface Water Mitigation Measures ................................................................................ 5-162
3.3.5.2
Release from Regulated Dams ....................................................................................... 5-164
3.3.5.3
Receiving Water Monitoring Program ............................................................................. 5-166
3.3.5.4
Groundwater Mitigation Measures .................................................................................. 5-167
3.3.5.5
Groundwater Monitoring .................................................................................................. 5-167
3.3.6 3.4
Proposed EA Conditions using Measurable Indicators and Standards ...................... 5-169 NOISE AND VIBRATION ............................................................................................... 5-183
3.4.1
Description of Environment ......................................................................................... 5-183
3.4.1.1
Sensitive Receivers ......................................................................................................... 5-183
3.4.1.2
Baseline Noise Monitoring............................................................................................... 5-183
3.4.2
Environmental Value ................................................................................................... 5-183
3.4.3
Assessment of Impacts on the Environmental Values ............................................... 5-184
3.4.3.1
Potential Impacts ............................................................................................................. 5-184
3.4.3.2
Assessment Methodology ............................................................................................... 5-184
3.4.3.3
Noise Criteria .................................................................................................................. 5-185
3.4.3.4
Modelled Noise Impacts .................................................................................................. 5-187
3.4.4
Proposed Environmental Protection Objective ........................................................... 5-189
3.4.5
Control Strategies ....................................................................................................... 5-189
3.4.6
Proposed EA Conditions using Measurable Indicators and Standards ...................... 5-190
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3.5
WASTE ........................................................................................................................... 5-191
3.5.1
Description of Environment ......................................................................................... 5-191
3.5.2
Environmental Values ................................................................................................. 5-192
3.5.3
Assessment of Impacts on the Environmental Values ............................................... 5-192
3.5.3.1
Potential Impacts ............................................................................................................. 5-192
3.5.4
Proposed Environmental Protection Objective ........................................................... 5-193
3.5.5
Control Strategies ....................................................................................................... 5-193
3.5.5.1
3.5.6 3.6
Waste Management Plan Overview ................................................................................ 5-194
Proposed EA Conditions using Measurable Indicators and Standards ...................... 5-196 LAND .............................................................................................................................. 5-196
3.6.1
Description of Environment ......................................................................................... 5-196
3.6.1.1
Soil and Land Suitability Assessment ............................................................................. 5-197
3.6.2
Environmental Value ................................................................................................... 5-204
3.6.3
Assessment of Impacts on the Environmental Values ............................................... 5-204
3.6.3.1
Potential Impacts on Land ............................................................................................... 5-204
3.6.4
Proposed Environmental Protection Objective ........................................................... 5-205
3.6.5
Control Strategies ....................................................................................................... 5-206
3.6.6
Proposed EA Conditions using Measurable Indicators and Standards ...................... 5-213
3.7
NATURE CONSERVATION ........................................................................................... 5-221
3.7.1
Description of Environment ......................................................................................... 5-221
3.7.1.1
Assessment Methodology ............................................................................................... 5-221
3.7.1.2
Terrestrial Flora Values ................................................................................................... 5-222
3.7.1.3
Terrestrial Fauna Values ................................................................................................. 5-227
3.7.1.4
Aquatic Ecology Values................................................................................................... 5-228
3.7.1.5
Stygofauna ...................................................................................................................... 5-230
3.7.2
Environmental Value ................................................................................................... 5-230
3.7.3
Assessment of Impacts on the Environmental Values ............................................... 5-230
3.7.3.1
Potential Impacts on Flora Values................................................................................... 5-230
3.7.3.2
Potential Impacts on Communities on Conservation Significance ................................... 5-231
3.7.3.3
Potential Impacts on Fauna Values ................................................................................. 5-232
3.7.3.4
Cumulative Impacts on Flora and Fauna......................................................................... 5-233
3.7.3.5
Potential Impacts on Aquatic Ecology ............................................................................. 5-234
3.7.3.6
Potential Impacts on Stygofauna ..................................................................................... 5-236
3.7.4
Proposed Environmental Protection Objective ........................................................... 5-238
3.7.5
Control Strategies ....................................................................................................... 5-238
3.7.5.1
Mitigation of Potential Terrestrial Flora and Fauna Impacts ............................................ 5-238
3.7.5.2
Mitigation of Potential Aquatic Impacts ........................................................................... 5-240
3.7.5.3
Downstream Wetland Protection ..................................................................................... 5-242
3.7.5.4
Pest and Weed Management Plan .................................................................................. 5-243
3.7.5.5
Mitigation of Potential Stygofauna Impacts ..................................................................... 5-243
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3.8
COMMUNITY .................................................................................................................. 5-244
3.8.1
Description of Environment ......................................................................................... 5-244
3.8.2
Environmental Value ................................................................................................... 5-244
3.8.3
Assessment of Impacts on the Environmental Values ............................................... 5-244
3.8.4
Proposed Environmental Protection Objective ........................................................... 5-245
3.8.5
Control Strategies ....................................................................................................... 5-245
3.8.6
Proposed EA Conditions using Measurable Indicators and Standards ...................... 5-247
3.9
ENVIRONMENTAL REPORTING .................................................................................. 5-248
3.9.1
Proposed EA Conditions using Measurable Indicators and Standards ...................... 5-248
3.10
CONTINUOUS IMPROVEMENT .................................................................................... 5-249
3.11
STAFF TRAINING .......................................................................................................... 5-249
3.12
ENVIRONMENTAL AUDITING ...................................................................................... 5-249
3.13
ENVIRONMENTAL MANAGEMENT PLAN MILESTONES .......................................... 5-250
4.0
REFERENCES ......................................................................................... 5-251
LIST OF FIGURES Figure 5.1
Project Location .......................................................................................................... 5-7
Figure 5.2
Local Context Map ...................................................................................................... 5-8
Figure 5.3
Cadastre Underlying and Adjacent to the Project ..................................................... 5-14
Figure 5.4
Site and Infrastructure Layout ................................................................................... 5-16
Figure 5.5
Mine Sequencing – Progress by year in Operation (MLA50254) ............................. 5-18
Figure 5.6
Mine Stage Plan – Year 01 ....................................................................................... 5-20
Figure 5.7
Mine Stage Plan – Year 02 ....................................................................................... 5-21
Figure 5.8
Mine Stage Plan – Year 03 ....................................................................................... 5-22
Figure 5.9
Mine Stage Plan – Year 04 ....................................................................................... 5-23
Figure 5.10
Mine Stage Plan – Year 05 ....................................................................................... 5-24
Figure 5.11
Mine Stage Plan – Year 08 ....................................................................................... 5-25
Figure 5.12
Mine Stage Plan – Year 10 ....................................................................................... 5-26
Figure 5.13
Mine Stage Plan – Year 15 ....................................................................................... 5-27
Figure 5.14
Mine Stage Plan – Year 20 ....................................................................................... 5-28
Figure 5.15
Mine Stage Plan – End of Mining ............................................................................. 5-29
Figure 5.16
Process Flow Diagram .............................................................................................. 5-32
Figure 5.17
TDP Dimensions ....................................................................................................... 5-37
Figure 5.18
Horse Creek Diversion Proposal (PB 2014) ............................................................. 5-40
Figure 5.19
Water Balance Schematic of the CHPP ................................................................... 5-43
Figure 5.20
Schematic of the Site Water Management System .................................................. 5-48
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Figure 5.21
Conceptual Design of Clean Water Diversion Drain ................................................. 5-67
Figure 5.22
MIA Water Management Infrastructure..................................................................... 5-69
Figure 5.23
Northern TSF (TDN) Water Management Infrastructure .......................................... 5-70
Figure 5.24
Northern Alternative TSF (TDNA) Water Management Infrastructure ...................... 5-71
Figure 5.25
Infrastructure MLA Drainage Catchments ................................................................ 5-72
Figure 5.26
Typical culvert outlet cross-section ........................................................................... 5-75
Figure 5.27
Proposed Public Roads Closures and Upgrades ..................................................... 5-77
Figure 5.28
Elimatta Project Final Landform (MLA 50270, MLA 50271) ................................... 5-101
Figure 5.29
Elimatta Project Final Landform (MLA 50254) ........................................................ 5-102
Figure 5.30
TDP Final Landform Design ................................................................................... 5-105
Figure 5.31
Typical Waste Dump Final Landform Profile .......................................................... 5-108
Figure 5.32
Surface TSF Final Landform Design ...................................................................... 5-110
Figure 5.33
Land Disturbance .................................................................................................... 5-116
Figure 5.34
Water Courses in the Project Area ......................................................................... 5-132
Figure 5.35
Referable wetlands in the vicinity of the MLA areas ............................................... 5-134
Figure 5.36
Referable wetlands in the vicinity of the Rail and Services Corridor ...................... 5-135
Figure 5.37
Base Case MLA 50254 1:100 Year Flood Depth (Parsons Brinckerhoff 2014) ..... 5-145
Figure 5.38
Base Case MLA 50270 1:100 Year Flood Depth (Parsons Brinckerhoff 2014) ..... 5-146
Figure 5.39
Probable Maximum Flood Extent Diversion Stage 3 (MLA 50254) (PB 2014) ....... 5-159
Figure 5.40
Groundwater Monitoring Locations ......................................................................... 5-182
Figure 5.41
Distribution of Soil Management Units within the Elimatta Project MLA Areas ...... 5-200
Figure 5.42
Distribution of Soil Management Units within the Elimatta Project Rail and Services Corridor ................................................................................................................... 5-201
Figure 5.43
Vegetation Communities of the Northern MLA Area .............................................. 5-224
Figure 5.44
Vegetation Communities of the Southern MLA Area .............................................. 5-225
LIST OF TABLES
Table 5.1
EM Plan Content Requirements Summary ................................................................. 5-1
Table 5.2
Supporting Studies...................................................................................................... 5-4
Table 5.3
Proposed Mining Leases ............................................................................................ 5-9
Table 5.4
Underlying and Adjacent Mining Tenures – MLA Areas ............................................. 5-9
Table 5.5
Mining Tenures Underlying the Rail and Services Corridor...................................... 5-10
Table 5.6
Real Property Descriptions Underlying the Project .................................................. 5-11
Table 5.7
Real Property Descriptions Adjacent to the Project .................................................. 5-12
Table 5.8
TSF Design Parameters ........................................................................................... 5-35
Table 5.9
Calculated Overall Water Usage Demands for the Project ...................................... 5-45
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Table 5.10
Summary of Water Management System Changes Over the Mine Life ................... 5-47
Table 5.11
Void Characteristics of Mine Pit E1 .......................................................................... 5-49
Table 5.12
Void Characteristics Mine Pit E2 .............................................................................. 5-50
Table 5.13
Void Characteristics Mine Pit N ................................................................................ 5-50
Table 5.14
Void Characteristics Mine Pit W ............................................................................... 5-51
Table 5.15
Dam Characteristics EV1 .......................................................................................... 5-52
Table 5.16
Dam Characteristics EV2 .......................................................................................... 5-52
Table 5.17
Dam Characteristics EV3 .......................................................................................... 5-53
Table 5.18
Dam Characteristics EV4 .......................................................................................... 5-54
Table 5.19
Dam Characteristics TDN ......................................................................................... 5-55
Table 5.20
Dam Characteristics TDNA ....................................................................................... 5-56
Table 5.21
Dam Characteristics TDP ......................................................................................... 5-57
Table 5.22
Dam Characteristics RW1 ........................................................................................ 5-58
Table 5.23
Dam Characteristics SD1 ......................................................................................... 5-58
Table 5.24
Dam Characteristics SD2 ......................................................................................... 5-59
Table 5.25
Dam Characteristics SD3 ......................................................................................... 5-59
Table 5.26
Dam Characteristics RW2 ........................................................................................ 5-60
Table 5.27
Dam Characteristics RW3 ........................................................................................ 5-61
Table 5.28
Dam Characteristics RW4 ........................................................................................ 5-62
Table 5.29
Culvert sizes at each location ................................................................................... 5-74
Table 5.30
Public Road Crossings ............................................................................................. 5-78
Table 5.31
Stock Route Crossings ............................................................................................. 5-78
Table 5.32
Load Sources and Operating Hours ......................................................................... 5-80
Table 5.33
Activities associated with the Project that would otherwise be considered ERAs .... 5-86
Table 5.34
Mining Activities and Annual Fees Associated with the Project ............................... 5-87
Table 5.35
Elimatta Mine Domains ............................................................................................. 5-89
Table 5.36
Completion Criteria, Indicators, Objectives and Rehabilitation Goals ...................... 5-91
Table 5.37
Design of Ripping Operations for Post-disturbance Surface Preparation .............. 5-103
Table 5.38
Proposed Rehabilitation Monitoring Locations ....................................................... 5-112
Table 5.39
Sensitive Receptors ................................................................................................ 5-117
Table 5.40
Air Quality Assessment Criteria .............................................................................. 5-123
Table 5.41
Annual Greenhouse Emissions for the Mine Operation ......................................... 5-127
Table 5.42
Annual Greenhouse Gas Emissions for the West Surat Link ................................. 5-127
Table 5.43
Horse Creek Water Quality Results ........................................................................ 5-137
Table 5.44
Rail and Services Corridor Surface Water Quality Results .................................... 5-140
Table 5.45
Existing Water Levels under Flood Conditions (Rail and Services Corridor) ......... 5-144
Table 5.46
Groundwater Exceedance Summary ...................................................................... 5-148
Table 5.47
Peak water levels for simulated design flood events .............................................. 5-154
Table 5.48
Target and Modelled Containment AEP of Dams on the Project Site .................... 5-157
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Table 5.49
Adopted Flow Release Triggers for Horse Creek Receiving Waters ..................... 5-166
Table 5.50
Mine Affected Water Release Points, Sources and Receiving Waters .................. 5-169
Table 5.51
Mine Affected Water Release Limits....................................................................... 5-169
Table 5.52
Release Contaminant Trigger Investigation Levels ................................................ 5-170
Table 5.53
Mine Affected Water Release During Flow Events ................................................. 5-173
Table 5.54
Receiving Waters Interim Contaminant Trigger Levels .......................................... 5-175
Table 5.55
Receiving Water Monitoring Points ......................................................................... 5-175
Table 5.56
Contaminant Release Limits to Land ...................................................................... 5-177
Table 5.57
Groundwater Monitoring Locations and Frequency ................................................ 5-178
Table 5.58
Groundwater Contaminant Trigger Levels .............................................................. 5-179
Table 5.59
Groundwater Contaminant Limits ........................................................................... 5-180
Table 5.60
Measured Background Noise Levels ...................................................................... 5-183
Table 5.61
Proposed Noise Limits ............................................................................................ 5-186
Table 5.62
Construction Noise Level Objectives ...................................................................... 5-186
Table 5.63
Proposed Airblast and Vibration Limits ................................................................... 5-187
Table 5.64
Noise Limits ............................................................................................................ 5-190
Table 5.65
Blasting Noise Limits............................................................................................... 5-191
Table 5.66
Agricultural Appraisal and Key Limitations of each Soil Management Unit ............ 5-202
Table 5.67
Final Land Use and Rehabilitation Approval Schedule .......................................... 5-214
Table 5.68
Landform Design..................................................................................................... 5-216
Table 5.69
Void Monitoring Locations and Frequency ............................................................. 5-216
Table 5.70
Void Water Quality Limits ....................................................................................... 5-216
Table 5.71
Size and Purpose of Regulated Dams.................................................................... 5-217
Table 5.72
Location of Regulated Dams .................................................................................. 5-218
Table 5.73
Storage Design for Regulated Dams ...................................................................... 5-219
Table 5.74
Regulated Dam Monitoring Locations and Frequency ........................................... 5-219
Table 5.75
Regulated Dam Water Quality Limits...................................................................... 5-219
Table 5.76
Summary of Milestones .......................................................................................... 5-250
LIST OF APPENDICES
Appendix A
Elimatta Project
Identified Interested and Affected Stakeholders (9 March 2012) ............................... 5-A
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LIST OF ABBREVIATIONS
AARC
-
AustralAsian Resource Consultants Pty Ltd
ACA
-
Aquatic Conservation Assessment
AHD
-
Australian Height Datum
ANC
-
Acid Neutralising Capacity
ANZECC
-
Australia New Zealand Environment and Conservation Council
ARD
-
Acid Rock Drainage
ARI
-
Average Recurrence Interval
BPA
-
Biodiversity Planning Assessment
CHPP
-
Coal Handling and Processing Plant
CHMP
-
Cultural Heritage Management Plan
CO
-
Carbon Monoxide
DAFF
-
Department of Agriculture, Fisheries and Forestry
dB
-
decibel
DSITIA
-
Department of Science, Information Technology, Innovation and the Arts
DERM
-
Department of Environment and Resource Management
DME
-
Department of Mines and Energy
EA
-
Environmental Authority
EC
-
Electrical Conductivity
EHP
-
Department of Environment and Heritage Protection
EIS
-
Environmental Impact Statement
EMM
-
Environmental Monitoring Manual
EMS
-
Environmental Management System
EM Plan
-
Environmental Management Plan
EP Act
-
Environmental Protection Act 1994
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EPBC Act
-
Environment Protection and Biodiversity Conservation Act 1999
EPC
-
Exploration Permit Coal
EPP
-
Environmental Protection Policy
ERA
-
Environmentally Relevant Activities
ESA
-
Environmental Sensitive Area
EV
-
Environmental Dam
FIFO
-
Fly-in fly-out
GAB
-
Great Artesian Basin
GBR
-
Great Barrier Reef
GDE
-
Groundwater Dependent Ecosystem
GGMP
-
Greenhouse Gas Management Plan
ha
-
Hectare
HME
-
Heavy Mechanical Equipment
kt
-
Kilotonnes
km
-
Kilometre
kVA
-
Kilo Watts
L
-
Litre
LIG
-
Low Intensity Grazing
QEPA
-
Queensland Environmental Protection Agency
m
-
Metre
m
2
-
Square metre
m
3
-
Cubic metre
mm
-
Millimetre
MDL
-
Mineral Development License
mg
-
Milligram
MIA
-
Mining Infrastructure Area
ML
-
Mining Lease
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MLA
-
Mining Lease Application
MMP
-
Mosquito Management Plan
mRL
-
Metre Reduced Level
MVA
-
Mega Volt Ampere
Mt
-
Million tonne
Mtpa
-
Million tonne per annum
MWh
-
Megawatt hour
NAG
-
Net Acid Generation
NAPP
-
Net Acid Producing Potential
NATA
-
National Association of Testing Authorities
NEC
-
Northern Energy Corporation Limited
NCWR
-
Nature Conservation Wildlife Regulation 2006
NO2
-
Nitrogen Dioxide
PB
-
Parsons Brinckerhoff
PM
-
Particulate Matter
PMF
-
Probable Maximum Flood
PPP
-
Parcel Prospecting Permit
PWMP
-
Pest and Weed Management Plan
QR
-
Queensland Rail
RE
-
Regional Ecosystem
REMP
-
Receiving Environment Monitoring Program
RPD
-
Real Property Descriptions
RO
-
Reverse Osmosis
ROM
-
Run of Mine
RW
-
Raw Water
SD
-
Sediment Dam
SHMS
-
Safety and Health Management System
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SIMP
-
Social Impact Management Plan
SMU
-
Soil Management Unit
SO2
-
Sulfur Dioxide
STP
-
Sewerage Treatment Plant
SWMS
-
Site Water Management Strategy
t
-
tonne/s
TAPM
-
The Air Pollution Model
TDS
-
Total Dissolved Solids
TN
-
Total Nitrogen
TOR
-
Terms of Reference
Tpa
-
Tonnes per annum
TSF
-
Tailings Storage Facility
TSP
-
Total Suspended Particulate
µg
-
Microgram
µm
-
Micrometre
µS
-
Micro Siemen
WBSM
-
Water and Salt Balance Model
WDRC
-
Western Downs Regional Council
WHO
-
World Health Organisation
WICET
-
Wiggins Island Coal Export Terminal
WMP
-
Waste Management Plan
WoNS
-
Weeds of National Significance
WSL
-
West Surat Link
VOC
-
Volatile Organic Compounds
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1.0
INTRODUCTION
Taroom Coal Pty Ltd (Taroom Coal) is the proponent for the Elimatta Project and applicant for the project mining leases and environmental authority. Taroom Coal is a wholly owned subsidiary of Northern Energy Corporation Limited (NEC), which is in turn a wholly owned subsidiary of New Hope Corporation Limited (New Hope). New Hope is an Australian publicly listed company with a long history dating to the early 1950s of coal mine development and operation in Queensland and overseas. The Elimatta Project is to develop and operate an open pit thermal coal mine and associated infrastructure, based on a 250 Million tonne (Mt) resource in the Surat basin, Southern Queensland, Australia. Taroom Cool has prepared an Environmental Impact Statement (EIS) for the Project and has submitted it to the Department of Environment and Heritage Protection (EHP) in April 2012. The EIS was re-submitted with revisions to the proposed Rail and Services Corridor assessment in November 2012. The EM Plan has been prepared in accordance with former Section 203 of the Environmental Protection Act 1994 (EP Act). This EM Plan will provide a description of the following:
Mining tenure(s);
Mining activities;
Environmental values and potential impacts from the Project on those values;
Commitments to impact prevention and mitigation measures; and,
Proposed EA condition(s) using measurable indicators and standards.
For each environmental value identified, an assessment of the beneficial and adverse impacts from the Project will be described. Environmental objectives and control strategies will be proposed for the protection of each environmental value and proposed EA conditions containing measurable standards and indicators developed. Table 5.1 below provides cross references to relevant sections of this document and describes how the requirements of former Section 203 of the EP Act have been met. Table 5.1
EM Plan Content Requirements Summary EM Plan Cross Reference
EP Act Section 203 Requirement 1 (a) The EM Plan must be in the approved form
-
1 (b) The EM Plan must describe the following— • each relevant mining lease; • all relevant mining activities; • the land on which the mining activities are to be carried out; • the environmental values likely to be
Section 1.3 Section 2.0 Section 1.5 Section 3.0
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Compliance Summary This table describes how the requirements of the EP Act have been met. The EM Plan is considered to be in the approved form. Section 1.3 describes relevant mining leases Section 2.0 describes all relevant mining activities Section 1.5 describes the land on which the mining activities are to be
2014
EM Plan Cross Reference
EP Act Section 203 Requirement
•
affected by the mining activities; the potential adverse and beneficial impacts of the mining activities on the environmental values
1 (c) The EM Plan must state any code of environmental compliance and standard environmental conditions that are to apply to the relevant mining activities 1 (d) The EM Plan must state, to the extent a code of environmental compliance does not apply to the relevant mining activities, the environmental protection commitments the applicant proposes for the mining activities to protect or enhance the environmental values under best practice environmental management. 1 (da) The EM Plan must state, to the extent the plan relates to mining activities in a wild river area—state the way in which the applicant proposes to minimise any adverse effect of the mining activities on the wild river area, having regard to the wild river declaration for the area. 1 (e) The EM Plan must state if a relevant mining lease is, or is included in, a significant project—state whether an EIS under the State Development Act, part 4, has been prepared for the project. 1 (f) The EM Plan must contain enough other information to allow the administering authority to decide the application and conditions to be imposed on the environmental authority.
1 (g) The EM Plan must contain another matter prescribed under an environmental protection policy or a regulation.
Elimatta Project
Section 1.6
Compliance Summary carried out Section 3.0 describes environmental values likely to be affected Section 3.0 describes potential adverse and beneficial impacts of the project The relevant code of environmental compliance is discussed in these sections
Section 3.0
Section 3.0 provides environmental protection commitments for environmental aspects of the Project.
Section 1.7
Section 1.7 states the application of Wild Rivers legislation to the Elimatta Project.
Section 1.8
Section 1.8 states the application of the State Development and Public Works Organisation Act 1971 to the Project.
-
This EM Plan has been developed in accordance with current best practices and standards. The EM Plan provides details of: • Project description; • Environmental Values • Potential Impacts • Environmental Protection Objectives; • Control Strategies; and • Proposed EA conditions.
Section 3.2.2 Section 3.4.2 Section 2.22 Section 3.5.5.1
5-2
Information is presented in this plan in order to environmental authority conditions to be imposed. Section 3.2.2 contains matters relevant to the environmental protection policy for Air Section 3.4.2 contains matters relevant to the environmental protection policy for Noise Section 2.22 contains matters relevant to the Environmental Protection Regulation 2008 Section 3.5.5.1 contains matters
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EP Act Section 203 Requirement
EM Plan Cross Reference
Compliance Summary relevant to the Environmental Protection (Waste Management) Regulation 2000
2 (a) The environmental protection commitments must be stated in a way that allows them to be measured and to be audited under part 11;
Section 3.0
2 (b) The environmental protection commitments must state the environmental protection objectives and the standards and measurable indicators, including, for example, objectives for progressive and final rehabilitation and management of contaminated land.
Section 3.0
2 (c) The environmental protection commitments must include control strategies to ensure the objectives are achieved, including for example, strategies for the following in relation to the mining activities— • Continuous improvement • Environmental auditing • Monitoring • Reporting • Staff training
Section 3.0 Section 3.9 Section 3.10 Section 3.9 Section 3.11 Section 3.12
3 (a) The environmental protection objectives mentioned in subsection (2)(b) must include specific rehabilitation objectives.
Section 2.23 Section 3.6
3 (b) The environmental protection objectives mentioned in subsection (2)(b) must identify the indicators that will be measured to establish when rehabilitation is, by reference to specific completion criteria, complete.
Section 2.23.4 Section 2.23.5 Section 2.23.12
(4) The indicators mentioned in subsection (3)(b) may be different for different parts of the land that have different types of disturbance.
Section 2.23.11 Table 5.36
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Section 3.0 provides environmental protection commitments and environmental authority conditions in a way that they can be easily understood, implemented, measured and audited. For each environmental aspect, Section 3.0 provides • Environmental Values • Potential Impacts • Environmental Protection Objectives; • Control Strategies / Commitments; and • Proposed EA conditions. Commitments and conditions are stated in a way that they can be easily understood, implemented, measured and audited. Control strategies are provided for each environmental protection objective in Section 3.0. Section 3.9 provides commitments for reporting to the EHP Section 3.10 provides commitments and opportunities for continuous improvement through the mine life. Section 3.11 provides commitments for staff training and development. Section 3.12 describes proposal for annual auditing Commitments to specific rehabilitation objectives are included within Section 2.23 and 3.6. Subsections of Section 2.23 include specific rehabilitation indicators which can be measured and compared to completion criteria to provide an indication of rehabilitation success. Specific rehabilitation goals, indicators, criteria are provided for each Domain (land disturbance type).
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Supporting environmental baseline assessment has been undertaken as part of the EIS in order to comprehensively describe the environmental values of the Project areas presented in this EM Plan. Once an EA has been issued for the Project, a Plan of Operations and Financial Assurance will be submitted to the Administrating Authority (Milestone 1). Table 5.2 details the baseline studies that have been undertaken for the project to date as part of the EIS. Table 5.2
Supporting Studies
Report Title
Year
Author
Elimatta Project - Soil and Land Suitability Assessment
Dec- 13
AARC
Elimatta Project - Visual Amenity Assessment
Nov-12
AARC
Elimatta Project - Contaminated Land Assessment: Preliminary Site Investigation
Oct-12
AARC
Elimatta Project - Transport Impact Study
Nov-12
AARC
Geochemical Assessment of the Elimatta Coal Project
Mar-12
Environmental Geochemistry International Pty Ltd
Water Management Strategy
Mar-14
JBT Consulting Pty Ltd
Elimatta Project Groundwater Assessment
Oct-12
Australasian Groundwater & Environmental Consultants Pty Ltd
Horse Creek Diversion Functional Design Report
Mar-14
Parsons Brinckerhoff Australia Pty Ltd
Horse Creek Northern MLA Hydraulic Study
Mar-14
Parsons Brinckerhoff Australia Pty Ltd
Horse Creek Base Case (Natural Conditions) and Diversion Flood Study for Elimatta Mine
Mar-14
Parsons Brinckerhoff Australia Pty Ltd
Elimatta Coal Mine - Air Quality and Greenhouse Gas Assessment
Mar-14
ASK Consulting Engineers Pty Ltd
Elimatta Project - Greenhouse Gas Management Plan
Mar-14
AARC
Elimatta Coal Mine - Noise Impact Assessment
Mar-14
ASK Consulting Engineers Pty Ltd
Elimatta Project - Waterway Morphology and Aquatic Ecology Assessment Report
Mar-14
AARC
Elimatta Project - Terrestrial Flora and Fauna Assessment
Mar-14
AARC
Rail and Services Corridor - Terrestrial Ecology Assessment
Mar-14
AARC
Stygofauna Survey - Phase 1 and 2
Apr-12
Subterranean Ecology Pty Ltd
Non-Indigenous Cultural Heritage Assessment, Elimatta Project
Nov-11
Converge Heritage + Community
Elimatta Coal Project - Social Impact Assessment
Sep-12
AARC
Elimatta Coal Project - Social Impact Management Plan
Sep-12
AARC
Economic Impact Assessment
Mar-12
Synergies Economic Consulting
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Report Title
Year
Author
Environmental Risk Assessment
Nov-12
AARC
Elimatta Rail and Services Corridor Soil and Land Suitability Assessment
Aug-12
Land Resource Assessment and Management Pty Ltd
Non-Indigenous Cultural Heritage Assessment, Elimatta Project, Rail and Services Corridor
Oct-12
Converge Heritage + Community
Rail and Services Corridor - Aquatic Ecology Assessment
Mar-14
AARC
West Surat Rail Link Air Quality Assessment
Mar-14
ASK Consulting Engineers Pty Ltd
West Surat Rail Link Noise Impact Assessment
Mar-14
ASK Consulting Engineers Pty Ltd
West Surat Rail Link Hydraulic Study
Sep-12
Parsons Brinckerhoff Australia Pty Ltd
Stygofauna Survey and Assessment - Phase 3 and 4
Nov-12
Subterranean Ecology Pty Ltd
Transport Impact Assessment Addendum
Sep-13
AARC
Elimatta Mine Road Impact Assessment
Mar-14
Parsons Brinckerhoff Australia Pty Ltd
Road Use Management Plan (Draft)
Feb-14
Parsons Brinckerhoff Australia Pty Ltd
Groundwater Assessment Supplementary Report
Jan-14
Australasian Groundwater & Environmental Consultants Pty Ltd
Elimatta Stygofauna Habitat Assessment
Jan-14
Ecological Australia
Road Corridor Desktop Ecology Assessment
Mar-14
AARC
Pest and Weed Management Plan
Jan-14
AARC
Non-Indigenous Cultural Heritage Management Plan
Jan-14
AARC
Elimatta Project Environmental Offset strategy
Apr-14
AARC
1.1
THE ELIMATTA PROJECT
The Project is based on the development of an estimated 259 million-tonne (Mt) thermal coal resource of the Juandah formation in the Surat Basin, Queensland. The Project will involve open-cut mining using truck and excavator methods. Overburden and interburden will be disposed of both in-pit and in out-of-pit spoils dumps located on site and contiguous with the pit excavation. Processing will involve crushing, screening and washing to separate coal from waste materials. Fine waste rejects (tailings) will be partially dewatered, with water recycled to the processing plant, and pumped thickener underflow to dedicated Tailing Storage Facilities (TSFs). Coarse wastes will be dried and disposed of within spoil dumps. The Project is planned to mine up to 8.2 Million tonnes per annum (Mtpa) run of mine (ROM) coal to produce an average 5.0 Mtpa of product coal for export. The Project proposes a Rail and Services Corridor to accommodate 36 km of new rail, known as the Western Surat Link (WSL). The WSL will connect the Elimatta Project site to the proposed Surat Basin Rail (SBR) north of Wandoan, facilitating transport of product coal to port facilities at Gladstone. The proposed Rail and Services Corridor has been designed to service multiple users surrounding the
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Elimatta Project. The Corridor will also accommodate power and water supply infrastructure to the mine and other potential users.
1.2
PROJECT LOCATION
The Project is located approximately 45 km southwest of the township of Taroom in southern Queensland and approximately 380 km northwest of Brisbane as shown in Figure 5.1. The Project is located entirely within the Western Downs Regional Council area. Its local context is illustrated in Figure 5.2. Access to the Project site is from the Yuleba – Taroom Road which is aligned roughly parallel to, and approximately 25 km west of, the Leichhardt Highway. Along its alignment, this road is known by a number of alternative names. In the vicinity of the Project, north of its intersection with Bundi Road, the Yuleba – Taroom Road is most commonly referred to as Perretts Road.
Elimatta Project
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Figure 5.1
Elimatta Project
Project Location
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Figure 5.2
Elimatta Project
Local Context Map
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1.3
DESCRIPTION OF MINING TENURES
The Project currently consists of a proposed Rail and Services Corridor and three Mining Lease Applications (MLAs) including:
MLA 50254 (Lodged 2 June 2009) – containing the proposed open-cut pit areas;
MLA 50270 (Lodged 10 December 2009) – consists of the Coal Handling and Processing Plant (CHPP), rail load-out facility and other associated mine infrastructure including tailings storages and an accommodation village; and
MLA 50271 (Lodged 10 December 2009) – serves as a transport corridor, linking the two MLAs and providing a route between the CHPP and the mined pit.
The status and area of each MLA is provided in Table 5.3. Table 5.3
Proposed Mining Leases
Tenement
Name
Holder
Status
Area (Ha)
MLA50254
Elimatta
Taroom Coal
Application
2,779
MLA50270
Elimatta Transport
Taroom Coal
Application
1,075
MLA50271
Elimatta Infrastructure
Taroom Coal
Application
128.2
Total Area
3,982.2
Underlying and adjacent mining tenures associated with the Project MLA area are described in Table 5.4. Table 5.4
Underlying and Adjacent Mining Tenures – MLA Areas
Tenement
Holder
Status
Granted/Lodged
EPC 650
Taroom Coal
Granted
5 March 1998
4 March 2016
EPC 1171
Taroom Coal
Granted
13 December 2007
th
12 December 2014
EPC 1615
Glencore Coal Queensland Pty Ltd
Granted
6 August 2009
EPC 1603
Matilda Coal Pty Ltd
Granted
20 August 2012
MDL 449
Glencore Coal Queensland Pty Ltd
Granted
22 January 2014
MDL 411
Glencore Coal Queensland Pty Ltd
Granted
1 August 2012
Elimatta Project
5-9
th
Expiry th
th
th
th
th
5 August 2014 th
19 August 2015
nd
31 January 2019
st
st
31 August 2017
st
2014
Tenement
Holder
Status
Granted/Lodged
MLA 50279
Glencore Coal Queensland Pty Ltd
Application
3 September 2010
MLA 50277
Glencore Coal Queensland Pty Ltd
Application
29 July 2010
Expiry
rd
-
th
-
The Rail and Services Corridor is proposed to service the Elimatta Coal Project as well as other (potential) resource developments to the east, west and south. The Rail and Services Corridor is not proposed on a mining tenure. There are a number of alternate options available to “acquire” the land necessary for the Rail and Services Corridor. The various options are outlined below. a) Compulsorily acquire the land pursuant to the State Development and Public Works Organisation Act 1971, including obtaining a declaration of “infrastructure facility of significance”; b) Acquire the land under the Transport Infrastructure Act 1994; and c) Obtain registered easements over the land. Mining Tenures underlying the Rail and Services Corridor are described in Table 5.5. Table 5.5
Mining Tenures Underlying the Rail and Services Corridor
Tenement
Holder
Status
Granted/Lodged
MDL 449
Glencore Coal Pty Ltd
Granted
22 January 2014
EPC 787
Glencore Coal Pty Ltd
Granted
25 February 2003
MLA 55010
Comet Coal & Coke Pty Ltd
Application
31 January 2012
1.4
nd
th
st
Expiry st
31 January 2019 th
24 February 2016 -
RELEVANT STAKEHOLDER CONSULTATION
The Project area is surrounded by a number of individual landowners with access to both Perretts Road and Horse Creek. Real Property Descriptions are detailed in Section 1.5. Perretts Road provides access to a number of these local properties that will be affected by the Project. A list of affected and interested persons was provided to EHP on 29 October 2009 with the Draft TOR in compliance with Section 41 of the EP Act. A list of the Identified Interested and Affected Stakeholders (current to 9 March 2012) is provided in Appendix A. Taroom Coal has ongoing consultation with various Advisory Bodies and other stakeholders. Advisory Body and stakeholder consultation included one-on-one meetings with key stakeholders and affected persons and meetings of interested groups. This process included: Traditional Owners, those parties identified as Affected Persons under Section 38 of the EP Act, and other relevant government bodies.
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Consultation with Traditional Owners over the Project site has occurred in order to put in place a Cultural Heritage Management Plan (CHMP) with the Iman #2 people. Consultation remains ongoing with this party in order to conduct Indigenous cultural heritage assessments of the Project site and infrastructure areas. A Cultural Heritage Management Plan (CHMP) has been submitted and approved by the Department of Aboriginal and Torres Strait Islander and Multicultural Affairs.
1.5
REAL PROPERTY DESCRIPTIONS
The Real Property Descriptions (RPD) of properties underlying the Project MLAs and the proposed Rail and Services Corridor are presented in Table 5.6. Real Property Descriptions adjacent to the Project are detailed in Table 5.7. The development of the Project and associated infrastructure corridors potentially affects 33 Lots, six Regional Council Roads, one Stock Route, and one State Road. The majority of properties underlying the Project site are freehold status. Cadastral boundaries underlying and adjacent to the Project MLAs and Rail and Services Corridor are illustrated in Figure 5.3. It is noted that the land dedicated as a reserve for camping and water purposes (Lot 43 on Plan AB222) is proposed to be affected by the Project. Table 5.6 Tenement Number
Real Property Descriptions Underlying the Project
Tenement Purpose
MLA50254
Elimatta Project
MLA50271
Elimatta Transport
MLA50270
Elimatta Infrastructure
-
Rail and Services Corridor
Elimatta Project
Real Property Description
Tenure
1SP103977 2SP103977 33AB128 38AB188 37AB180 1AB241 43AB222 42AB241 41AB241* 131SP121742* 41AB241* 131SP121742* 132SP121742* 60FT900* 131SP121742* 132SP121742* 72FT590 39FT503 40FT503 41CP857459 42FT505 43FT506 52FT830 44FT507 45FT507 47FT508 49FT453 2SP177963
Freehold Freehold Freehold Freehold Freehold Freehold Reserve held by Trustees Freehold Freehold Freehold Freehold Freehold Freehold Freehold Freehold Freehold Freehold Freehold Leasehold Freehold Freehold Freehold Freehold Freehold Freehold Freehold Freehold Freehold
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Tenement Number
Tenement Purpose
Real Property Description
1RP204781 60FT900* 66FT521 58FT520 69SP137906 58FT556 59FT820 43FT65 1CP857459 51FT507 AAP14857 Note - * denotes a property underlies more than one tenement Table 5.7
1.6
Tenure Freehold Freehold Freehold Freehold Freehold Leasehold Freehold Freehold Leasehold Freehold Stock Route
Real Property Descriptions Adjacent to the Project Tenement
Lot on Plan
Proximity to MLA50254 (Elimatta), MLA50270 (Elimatta Transport) and MLA50271 (Elimatta Infrastructure)
46FT64 24SP174422
Proximity to MLA – (Rail and Services Corridor)
50FT508 1CP857459 51FT507 67FT873 40FT329
RELEVANT CODES OF ENVIRONMENTAL COMPLIANCE
The Minister may approve standard environmental conditions for environmentally relevant activities (ERAs) under section 549 of the Environmental Protection Act 1994. These conditions are contained in codes of environmental compliance (codes). Codes usually replace an environmental authority or development approval that is issued with conditions that have been drafted specifically for the particular operation. The Elimatta Project constitutes a Level 1 Mining Project in Queensland. This EM Plan proposes site specific environmental authority conditions to ensure the protection of environmental values. As such, no specific Code of Environmental Compliance is required for the Project.
1.7
WILD RIVERS LEGISLATION
The Queensland Parliament passed the Wild Rivers Act 2005 in October 2005. The purpose of the Act is to preserve the natural values of Wild Rivers. It does this by regulating most future development activities within a declared Wild River and its catchment area. A Wild River is a river system that has all, or almost all, of its natural values intact. For example, its flow regime, sediment regime and water quality will be in a near natural condition and it will have healthy riparian vegetation and connected wildlife corridors. These natural values provide the basis for sustaining healthy ecological processes in rivers and support the habitat needed for diverse native plant and animal communities. They also provide scenic and recreational appeal.
Elimatta Project
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The Project Site is located within the Upper Fitzroy River Catchment. This catchment is not currently declared or nominated for declaration under the Wild Rivers Act 2005. Therefore the Project has no impact on areas nominated or declared as wild rivers.
1.8
STATE DEVELOPMENT & PUBLIC WORKS ORGANISATION ACT 1971
Part 4 of the State Development and Public Works Organisation Act 1971 provides for coordination of environmental approval process for Significant Projects under the direction of the Coordinator General. The Elimatta Project has not made application for Significant Project status and is not seeking coordination of approvals under the State Development and Public Works Organisation Act 1971.
Elimatta Project
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Figure 5.3
Elimatta Project
Cadastre Underlying and Adjacent to the Project
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2.0
PROJECT DESCRIPTION
2.1
GENERAL OVERVIEW
The target commencement date for production is early 2019 with timing dependent on the availability of services and infrastructure required for power supply, water supply and product coal transportation and shipping. In summary, the major elements of the Project are:
Open cut mining over approximately 2,287 hectares (ha) (MLA 50254);
Out-of-pit stockpiling of spoil over approximately 183 ha (MLA 50254);
Relocation of Horse Creek and Perretts Road from within the mining area (MLA 50254);
Construction and operation of a CHPP and associated mine infrastructure, including tailings storages and an accommodation village over approximately 340 ha (MLA 50270);
Transportation of ROM coal from the pit to the CHPP via a dedicated haul road (MLA 50271);
Construction and operation of a multi user Rail and Services Corridor;
Rail loading at the Project site and transportation of product coal to the Wiggins Island Coal Export Terminal (WICET) in Gladstone via the WSL; and
Progressive rehabilitation, as well as ultimate rehabilitation, of the Project area once the site has been decommissioned.
The Project is estimated to employ an average of approximately 300 full time staff at full production with the potential for additional employees to be required during major operations and special tasks throughout the life of the mine. The Project area for the Elimatta EIS comprises the three identified MLAs, on which the mining and processing infrastructure are proposed for development. A Rail and Services Corridor to accommodate 36 km of new rail, known as the Western Surat Link (WSL), is also part of the Project. The proposed Rail and Services Corridor has been designed to service multiple users surrounding the Elimatta Project. The Corridor will also accommodate power and water supply infrastructure to the mine and other potential users. At the western end of the Rail and Services Corridor, two possible alignments are provided for connection to the Elimatta mine site. Only one of these options is intended for development. The final connection alignment will be dependent on agreements with other rail users. Both options have been considered in this EIS. The Proposed site and infrastructure layouts are presented in Figure 5.4.
Elimatta Project
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Figure 5.4
Elimatta Project
Site and Infrastructure Layout
5-16
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2.2
PROJECT LIFE AND MINE SEQUENCE
The proposed mine sequencing of the Project has been estimated for an operational period in excess of 32 years. Processing of stockpiles will potentially continue beyond the estimated mine life (32 years). The mine plan is designed to mine all of the economically viable resource to the limits of the MLA 50254 tenure boundary. The Project will be an open-cut operation. The spoil extraction and coal mining methodology to be employed utilises excavators and trucks mining designated blocks within the pit areas. Early construction works will address the realignment of Perretts Road outside of the mining area during the initial construction period. The mine plan has then been specifically devised to address the temporary and permanent relocation of Horse Creek, with much of the permanent relocation work being done early in the mine life. The diversions, temporary and final, have been designed to be robust such that adjustments can be made as experience accrues with the final diversion being in place for at least 20 years ahead of planned mine closure. The plan allows for the recovery of coal under the current creek alignment and for the diversion works to have time to stabilise and develop grass cover prior to use. The construction period is anticipated to take approximately 22 – 24 months with operations employees on site after 13 months. Once established, the initial operation will take approximately 36 months to ramp up to the full annual mine production rate up to 8.2 Mtpa ROM, with an average of 7.2 Mtpa. Including construction through to decommissioning and shutdown, the whole of Project “life” is expected be to 40 years. During the life of the Project, land disturbed as part of the development and operation of the Project will be progressively rehabilitated. Upon relinquishment of the ML areas, the rehabilitation land must meet the agreed post mining land use and value in accordance with the standards set in the Environmental Authority (EA) for the Project. The mine sequence is driven by a desire to mine the coal with the lowest strip ratio first, which will keep the operating costs to a minimum throughout the mine life. The central part of the mining area contains the lowest strip ratios. The current mine plan allows for mining of coal to the MLAs south and east boundaries, subject to profitability and market conditions later in the mine life. The mine sequence plot for the Project is shown in Figure 5.5.
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Figure 5.5
Elimatta Project
Mine Sequencing – Progress by year in Operation (MLA50254)
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2.3
EXPLORATION
The limits of the targeted ore body have been defined. Consequently, while resource definition drilling will proceed in advance of open pit development for mine production scheduling processes, no further exploration is proposed in association with the identified resource area. However, should any exploration be required, all activities will be conducted in accordance with the Project’s EA.
2.4
MINING
The Elimatta Project will be an open-cut operation. The spoil extraction and coal mining methodology to be employed for the Project utilises excavators and trucks mining designated blocks within the pit areas. The placement of the initial boxcut was determined by the need to:
Work around the constraints imposed by Horse Creek;
Be closest to the out-of-pit dump location;
Be close to the ROM processing area; and
Be in a low strip ratio coal area.
Because of the relatively shallow depth of the first coal in the mine schedule, which has around 20 m of overburden, minimal time is needed to establish a working face and working room to mine coal. The initial box cut and stage plan upon commencement of the mine is shown in Figure 5.6. The initial haul ramp and box cut excavation will be made through weathered overburden, then through fresh overburden along the top of coal to form the initial pit endwall and highwall. Free dig depths of approximately 8 – 13 m are expected dependent on type and size of machinery used. All fresh overburden and interburden rock types will require blasting for efficient excavation. Blasting will also be used to aid in the excavation of coal seams. Stage plans showing the face positions and the sequence of operations for Years 1, 2, 3, 4, 5, 8, 10, 15, 20, and End of Mining are shown from Figure 5.6 to Figure 5.15 respectively. These figures show the physical extent of excavations, location of stockpiles of topsoil and overburden, proposed progressive backfilling of excavations, water management infrastructure and the area disturbed at each major stage of the Project.
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Figure 5.6
Elimatta Project
Mine Stage Plan – Year 01
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Figure 5.7
Elimatta Project
Mine Stage Plan – Year 02
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Figure 5.8
Elimatta Project
Mine Stage Plan – Year 03
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Figure 5.9
Elimatta Project
Mine Stage Plan – Year 04
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Figure 5.10
Elimatta Project
Mine Stage Plan – Year 05
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Figure 5.11
Elimatta Project
Mine Stage Plan – Year 08
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Figure 5.12
Elimatta Project
Mine Stage Plan – Year 10
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Figure 5.13
Elimatta Project
Mine Stage Plan – Year 15
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Figure 5.14
Elimatta Project
Mine Stage Plan – Year 20
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Figure 5.15
Elimatta Project
Mine Stage Plan – End of Mining
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2.5
SPOIL DUMPING
A total of 1,152,535,104 bcm of waste (overburden and interburden) is planned for extraction over the mine life. Excavated waste is to be disposed of in out-of-pit dumps initially and then backfilled behind the mining void. Waste is expected to swell by a factor of 1.05 – 1.3 following excavation. Waste characterisation indicates the Project overburden/interburden, floor, washery waste and coal materials are not likely to be acid producing or release significant salinity or metals/metalloids, and will not require special handling for acid rock drainage (ARD) or neutral drainage control (EGI 2012). Initial sodicity testing indicates that some overburden/interburden materials are likely to be sodic and dispersive, and may be subject to surface crusting and high erosion rates if placed in the surface of dumps and exposed directly to rainfall (EGI 2012). Placement of spoil with known sodic/dispersion potential will preferentially avoid dump surface areas. Dump surface materials may be treated (with gypsum or lime) if erosion cannot otherwise be controlled. Two out-of-pit dumps are required for the Project, located in the south western corner and in the northern section of the southern mining lease area. Spoil dump locations are provided on mine stage plans, Figure 5.6 to Figure 5.15. Dump construction will be in 15 m lifts to a maximum height of 50-70 m above the natural ground level. A maximum final slope of 1V:6H is proposed for dump slopes to ensure long term stability. Rock lined drains and or sized rock mulch will be utilised to prevent erosion of dumps where required. This outer slope geometry and surface treatment will ensure adequate geotechnical stability and safe assessability, while minimising the catchment and erosion potential of the slope. In-pit dumping of excavated waste will occur after the initial box cut becomes available for dumping. As waste is excavated from the active strip, it is transported to and dumped into the previously mined void for disposal. Due to the swelling effect of excavated waste, in-pit dumps will be elevated above the natural surface level to a maximum height of 40 – 50 m.
2.6
PROCESSING ACTIVITIES
The CHPP is required to process up to 8.2 Mtpa of ROM coal and to achieve 7,000 run hours per annum. The CHPP has a nameplate capacity of 1,100– 1,200 tph to achieve a targeted 5.0 Mtpa of product coal. Processing will involve crushing, screening and washing to separate coal from waste materials. Fine waste rejects will be partially dewatered, with water recycled to the processing plant, and pumped thickener underflow to dedicated TSFs. Coarse wastes will be dried and disposed of within spoil dumps. The proposed location of the process plant is shown in Figure 5.4. Processes to be used in the CHPP include:
Hopper with feeder breaker;
Secondary sizer station;
Magnetic separation as a means of tramp detection;
Vibratory feeder bin;
Two stage crushing with hammer mill and double roll crusher;
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Fine fraction discarded as tailings (without flotation); and
Provision for a wet pre-treatment system if needed.
The process plant is designed for 24 hour per day operation treating a feed comprising on average 7.2 Mtpa of ROM coal. The tailings are pumped to the TSFs – purpose constructed storage dams – for the first ten years; thereafter, to the in-pit void. Figure 5.16 shows the conceptual plant flowchart.
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Figure 5.16
Elimatta Project
Process Flow Diagram
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2.7
PRODUCT HANDLING
Product coal discharged from the processing plant reports to the product stockpiles. The product handling system transports the product coal to two separate 50,000 t product coal stockpiles. When full, each free fall stock pile has 11,000 t of live capacity – approximately one train load. A coal valve system delivers the product coal onto the train load out conveyor and load out bin. The flood (or volumetric) loading system consists of a 250 t train load out bin, discharge gate and associated telescopic loading chute. This is the simplest form of a train loading system and includes an overload removal facility and local control room. The Proponent is proposing to transport product coal by rail, from the mine to Wiggins Island Coal Terminal in Gladstone for export. The proposed route will involve the following rail connections (in order from mine to port):
36 km – the West Surat Link (WSL)
210 km – Surat Basin Rail (SBR)
110 km - Aurizon Moura System
70 km – Aurizon Aldoga Connection
Development of the WSL has been incorporated as a component of the Elimatta Project’s Rail and Services Corridor. Product coal is to be transported via the WSL to join the Surat Basin Rail (SBR) approximately 10 km northeast of the Wandoan township. The Rail and Services Corridor will extend approximately 36 km, with a corridor width of 100 m, covering a total area of approximately 360 ha. The WSL and other supporting infrastructure (power and water supply lines) will occupy a smaller footprint within the Rail and Services Corridor. The transport and services infrastructure proposed within the Rail and Services Corridor will be multi-user infrastructure, supplying the Elimatta Project as well as other surrounding users.
2.8
CHPP REJECTS
2.8.1
Coarse Rejects
The coarse rejects handling systems consists of an initial rejects conveyor to transport rejects from the CHPP to the rejects stacking conveyor. The rejects stacking conveyor then transports the reject material to a rejects bunker located on the ROM pad. Rejects discharged to the bunker are reclaimed to trucks using a FEL. The coarse rejects will be trucked to the spoil dumps for disposal.
2.8.2
Tailings (Fine Rejects)
The Elimatta Project proposes sub-aerial deposition of tailings initially in two surface TSFs and subsequently within an in-pit TSF. The disposition of tailings within the two surface TSFs (Tailings Dam North (TDN) and Tailings Dam North Alternative (TDNA)) will be cycled intermittently in lifts of approximately 1 m to facilitate full depth consolidation of tailings material, improve shear strength of deposited tailings and lower the overall rate of fill of the TSFs. Once mining is completed within the northern void, the residual void will be utilised as a tailings dam (Tailings Dam Pit (TDP)). Flocculants will be used within the rejects thickener to assist with the separation of the underflow and overflow streams. The rate of rise of the tailings will be minimised to allow tailings to stabilise as
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quickly as possible and ensure efficient coagulation (settling out of the suspended fines to produce clean water). Supernatant water will be recycled back to the CHPP. Consolidation and desiccation will be facilitated where possible. A tailings characterisation and TSF design study was undertaken for the Project’s EIS and are summarised in this section.
2.8.3
Tailings Characterisation
2.8.3.1
Physical properties of Tailings
According to A&B Mylec (2010), it is anticipated that the tailings will comprise the -0.125 mm fraction, making up an estimated 50% of the CHPP rejects averaging 1.2 Mtpa, although consideration has also been given to a -0.063 mm fraction tailings (up to about 1 Mtpa). FL Smith reported (in A&B Mylec 2010) the anticipated specific gravity of the tailings to be 2.18 (compared with about 2.65 for normal mineral matter, implying a carbonaceous content of about 35%). This value may be higher than reality. It is envisaged that the tailings will be deposited at 25% initial solids, which is the percent solids conventionally employed throughout Queensland’s Bowen and Surat Basins, in the latter case handling similar ROM coal from the same or similar coal seams to those encountered at the Project. It is anticipated that the Elimatta tailings will settle and consolidate to about 48% solids or a dry 3 density in the order of 0.58 t/m in both the surface TSFs and the TDP. Allowing for the amount of 2 water lost to entrainment within the tailings voids, evaporation losses of the order of 0.9 m/m /year from ponded water, evaporation from wet and dry exposed tailings on the upper beach, and seepage 2 losses of the order of 0.07 m/m /year, the potential recoverable water is anticipated to be in the order of approximately 36% of the total water discharged with the tailings. The tailings would consolidate further on desiccation, with most of the additional water released being lost to evaporation. 2.8.3.2
Chemical Properties of Tailings
EGi conducted a Geochemical Assessment of the Project (2012) as part of the EIS. The investigation found:
pH and EC values indicate a lack of significant existing acidity and salinity in tailings and coarse rejects.
Total sulphur is low for both tailings and coarse rejects, reaching a maximum of 0.29%.
Acid base plots described in EGi (2012) show all rejects samples to have a negative Net Acid Production Potential (NAPP).
Most of the single addition Net Acid Generation (NAG) results are less than 4.5 but are affected by organic acids, and are likely to overestimate the acid potential of these samples.
The calculated NAG values for all samples are negative, indicating that the acid generated in the standard NAG test for these samples is organic, and that materials represented by these samples are not likely to be acid producing under field conditions.
Overall, ABCC results suggest that the acid buffering minerals within the rejects tested are generally reactive, and that the ANC would be mainly effective.
Generally no significant enrichment of metals or metalloids is indicated.
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Results indicate that Project tailings, and rejects, represented by the samples tested by EGi (2012), are likely to be non-acid forming (NAF), with the rejects also likely to have significant excess buffering capacity. Tailings and rejects were also not significantly enriched in elements of environmental concern and water extracts indicate metals and metalloids are not likely to be mobilised to any significant extent from circum-neutral to slightly alkaline leachates.
2.8.4
Tailings Storage Facility Design
Over the life of the Elimatta Project, tailings will be deposited into three TSFs, locations are provided in Figure 5.4. Key design parameters for the TSFs are contained in Table 5.8. It is proposed that, to the extent practicable, the tailings discharge outlet will be moved around the perimeter of the TSFs to control the location of the decant pond and maximise the potential for cycling tailings deposition over the full storage area to maximise settling; consolidation and desiccation between layers; and, the clarification of supernatant water for recycling to the CHPP. Rehabilitation of the TSFs is detailed in Section 2.23.11 of the EM Plan. Table 5.8
TSF Design Parameters Design Standard
Storm Event 1 in 2 year 1 in 1000 year, 24 hr Greater of: 1 in 100 year 24 hr storm event plus maximum operating volumes for average climatic conditions or 1 in 100 year wet season annual rainfall sequence Surface TSF Storage Capacity TDN TDNA Tailings Characteristics
In-Pit TSF Storage Capacity TDP Tailings Characteristics
TSF Embankments General
Construction
Elimatta Project
Design Application Temporary diversion structures during construction TSF emergency spillway erosion protection TSF Storage Capacity
3
11.6 million m 3 9.9 million m Initial solids at discharge = 25%, Consolidated solids by weight = 48% Specific Gravity = 2.18 Recoverable tailings water = 36% (of discharge) 3 Dry settled density = 0.58 t/m Tailings beach slope =>10% 3
38.3 million m (available Year 10 onwards) Initial solids at discharge = 25%, Consolidated solids by weight =48% Recoverable tailings water =36% (of discharge) 3 Dry settled density = 0.58 t/m
TDN and TDNA freeboard of 2 m. Containment Walls 3H:1V. TDP fill to 11 m below ground level Zoned starter embankment constructed of run of mine
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Design Standard Storm Event
2.8.4.1
Design Application waste, consisting of low permeability zone and structural fill zone. Containment walls built in a series of stages of variable height to a maximum of 16 m. Excess rainfall runoff to be directed to purpose-built channel structures. Walls constructed from clayey spoil compacted in nominal loose layer thicknesses of 300 mm, using vibrating sheepsfoot and flat drum rollers.
Surface TSFs (TDN and TDNA) 3
The proposed TDN has a capacity of 11.6 million m , allowing a final freeboard of 2 m for temporary stormwater storage and future rehabilitation purposes, and will accommodate the equivalent of 9.0 years of projected tailings production under the proposed cycling strategy. The rate of rise of tailings into Dam TDN will be less than 2.0m/year under the proposed cycling strategy (the rate of rise reducing due to the increasing area of the storage as it fills). 3
The proposed TDNA has a capacity of 9.9 million m , allowing a final freeboard of 2 m for temporary stormwater storage and future rehabilitation purposes. Dams TDN and TDNA together will accommodate 16.7 years of projected tailings production under the proposed cycling strategy. The rate of rise of tailings in Dam TDNA will be approximately 3.6 m/year under the proposed cycling strategy. It is anticipated that the tailings stored in the surface TSFs will undergo consolidation and desiccation for many years before final rehabilitation is required, which is expected to achieve sufficient shear strength to allow cover placement using trucks and dozers. To ensure this, surface water will be drained from the surface to facilitate consolidation and desiccation. Prior to cover placement being attempted, the (peak and remoulded) shear strength profile with depth of the consolidated and desiccated tailings will be assessed by vane shear strength testing. 2.8.4.2
In-Pit TSF (TDP)
Beyond Year 10, the Northern Void becomes available for tailings deposition, at which point it will be 3 re-designated as TDP (Figure 5.17). The proposed TDP has a capacity of 38.3 million m to about 11 m below ground level, accommodating tailings production to the end of mining in Year 32. This will take the tailings above the depth of weathering, estimated to be at about 25 m below ground. However, the clay-rich nature of the undisturbed pit walls will ensure that seepage through the pit walls will be minimised. The rate of rise of tailings in the TDP reduces from an initially very rapid rate to a final, still high rate of about 2.3 m/year.
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Figure 5.17
2.9
TDP Dimensions
SURFACE WATER DIVERSION
Horse Creek, an ephemeral tributary of the Dawson River, passes centrally through MLA 50254 and to the east of MLAs 50271 and 50270. Horse Creek has been identified as a significant surface constraint for mining activities in MLA 50254. The Project Stage Plan has been specifically devised to address a short term, temporary, then permanent relocation of Horse Creek. The plan allows for the recovery of coal from underneath the existing Horse Creek, and for the excavated creek diversion to have time to stabilise and develop vegetation prior to being commissioned in order to minimise erosion and sediment runoff. The diversion of Horse Creek will occur in four distinct stages all of which are completed in the first six years of mine operations. The diversion, temporary and final, will be in operation in excess of 25 years prior to mine closure. As a result, ample opportunity is available to monitor the performance of the channel and to make improvements during life of mine, if required. At mine closure the diversion will not require post mining lease maintenance.
2.9.1
Horse Creek Diversion
The diversion of Horse Creek was designed in consideration of the DNRM Draft Manual – Works that interfere with water in a watercourse: Watercourse diversions. A comprehensive diversion proposal is documented in Horse Creek Diversion Functional Design Report (Parsons Brinckerhoff 2014) (Appendix L).
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The timeframe and diversion sequence of Horse Creek has been driven by the need to;
Allow sufficient timing between development and commissioning;
Ensure the lowest strip ratio coal is still able to be mined early in the mine life; and,
Ensure future mining and dumping operations are not constricted by the location.
The key objectives of diverting the Project reach of Horse Creek are as follows:
To provide access to the coal resource in a staged manner to suit mine planning timeframe requirements;
To provide flood-control to prevent inundation of pits and coal processing or storage areas during flood events;
To construct the diversion such that it is self-sustaining and includes existing natural geomorphic, hydraulic, and ecological functions of the creek and surrounding landscape as far as is practically possible given the project constraints. It is important to note that it is unlikely to be feasible to return the system to its pre-disturbance condition;
To enhance channel stability using natural methods and reduce long term channel maintenance requirements; and
To ensure no liability is imposed on the State, the proponent or the community to maintain the diversion and its associated components.
Parsons Brinckerhoff Australia Pty Ltd (PB) was commissioned by Taroom Coal to undertake the detailed design and impact assessment of the Horse Creek diversion. All proposed temporary and permanent diversions are shown in Figure 5.18. 2.9.1.1
Diversion Stages
Stage One involves an initial permanent diversion of the middle segment of Horse Creek with a temporary upstream and downstream link to the existing stream. The initial diversion in natural ground occurs in Year 0, prior to commencement of mining operations, and will be put into use in Year 1. This diversion is outside the pit and dump footprint but within the mining lease. Stage Two involves a temporary diversion across a large meander loop upstream of Stage One to facilitate mining under the final upstream diversion footprint. The Stage Two diversion alignment follows a gently meandering planform through the existing alluvial floodplain, cutting off a significant meander bend in the existing Horse Creek thalweg. The diversion will entail the construction of a low flow channel only, with levees to the west to protect the active pits from flood inundation. Stage Two will be constructed in operational Year 2 of the Project. The Stage Three diversion will be constructed to be operational in Year 4. The diversion will be excavated partially through natural ground, and partially through mine spoil. Stage Three forms part of the final diversion landform, and consists of an engineered floodplain through mine spoil, approximately 200 m wide, containing a meandering low flow channel, as well as a low flow channel constructed through the natural floodplain prior to re-connecting to Horse Creek at the downstream extent of the diversion. Stage Four consists of a final permanent diversion on fill in the south, termed the permanent upstream diversion. It will be constructed in Year 5 of mining operation. It will be put into use in Year 10, thus having this period to stabilise before being opened to full flows. The
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complete diversion will have in excess of 15 years until the mine closes to refine the diversion structure to ensure it will be stable post-mining. Stage Four will be constructed to be operational in year 5 of mining operations and will be constructed entirely through mine spoil. This section completes the final landform of the permanent diversion, which by this time incorporates Stage Four, part of Stages One and Three. The Stage Four diversion will comprise an engineered floodplain, approximately 200 m wide, containing a meandering low flow channel, and will incorporate a 100 m wide fill bund between the engineered floodplain and final void location.
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Figure 5.18
Elimatta Project
Horse Creek Diversion Proposal (PB 2014)
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2.9.2
Revegetation
Growth of grasses, trees and shrubs on banks will be promoted following completion of construction in order to improve stability of the landform and achieve rehabilitation objectives. It is noted that the naturally treed banks of Horse Creek are significantly steeper than the proposed diversion landform with the trees and clayey soils providing natural stability. It is envisaged as part of the natural adjustment process the banks will steepen somewhat and the bed widen. Further details of revegetation of the diversion are provided in Section 2.23.11.6.
2.10
WATER REQUIREMENTS AND SUPPLY
A detailed Site Water Management Strategy (SWMS), developed by JBT Consulting Pty Ltd, will be implemented for the Project pertaining to water usage, supply, storage and management.
2.10.1
Water Usage
2.10.1.1
Construction Water Usage
Water will be required during the construction period of the Project to satisfy the demands associated with the following:
Moisture content adjustment for all earthworks associated with the construction of water storage dams, earthworks pads, flood levees, creek diversions etc.;
Dust suppression on all cleared construction areas;
Potable water for construction staff; and
Concrete mixing.
Approximately 800 Ml/a will be required during the construction phase of the Project, based on 200 Ml/a for dust suppression, 500 Ml/a for earthworks moisture adjustment, 80 Ml/a for potable water (excluding any allowance for vehicle washing) and nominally 20 Ml/a for concrete mixing. The primary requirement for providing a reliable water supply to the Project, both during the construction and operations periods, is the securing of a reliable external water supply source. Taroom Coal has advised that water will be sourced via an external water supply from a third party commercial water supplier. This will be delivered on a take or pay basis. The external water supply is intended to be pumped into Raw Water Dam 1 (RW1). If the stored water levels in the raw water dam become high enough to risk overtopping, the external water supply can be halted until such time that the dam has sufficient freeboard to prevent overtopping. During the construction period, the external water supply and RW1 will be established as priority infrastructure to provide a reliable water supply. 2.10.1.2
Operational Water Usage
Potable Water The predicted potable water usage for the Project has been calculated by determining the anticipated water usage associated with the following items:
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Consumption by mine staff (including all staff associated with administration, operations, CHPP, trades, capital works, shut down and visitors);
Consumption by accommodation village staff;
Bath house usage by mine staff;
Wash down of heavy and light vehicles; and
Wash down of the MIA.
The water usage is calculated to vary depending on the mine staging year; although the variation is minor and only affects mine years 1 to 3. The maximum calculated potable water usage in 90 ML/a. CHPP Water Usage The CHPP water usage calculations have been based on a simple water balance through the CHPP to support an average throughput of 7.75 Mtpa ROM, taking into consideration the water contributions from the following component sources:
Water input to the CHPP via the ROM coal feed moisture content;
Water input to the CHPP via fine tailings return water;
Water input the CHPP as “make up” water to address water deficits;
Water output from the CHPP via the product coal moisture content;
Water output from the CHPP via the coarse rejects moisture content;
Water output from the CHPP via the fine tailings rejects moisture content; and
Water losses from the CHPP, arising due to the plant’s washing efficiency.
Figure 5.19 presents a schematic diagram of the annual water balance calculated for the proposed CHPP.
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Figure 5.19
2.10.1.3
Water Balance Schematic of the CHPP
Dust Suppression Water Usage
Predicted dust suppression water usage for the operations phase of the Project has been calculated by determining the anticipated water usage associated with the following items:
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Dust suppression on the central haul road linking the southern MLA 50254 with the northern MLA 50270;
Dust suppression on the MIA road leading off the central haul road;
Dust suppression on all the pit ramps leading off the central haul road;
Dust suppression on all the operational pit floors; and,
Dust suppression on the ROM stockpile.
The expected variation in water usage is reasonably steady for the Northern MLA 50270, ranging between a minimum of 245 Ml/a in mine year 1 to a maximum of 293 Ml/a between mine years 10 to 30. The expected water usage for the southern MLA 50254 is much more variable, ranging between a minimum of 399 Ml/a in mine year 1 to a maximum of 886 Ml/a in mine year 20. This variation is expected, as the mine staging affects the southern MLA 50254 more so than it does the northern MLA 50270, due to the movement of pits, pit ramps, spoil dumps and mining equipment as the mine progresses. The SWMS has been prepared assuming that water will be provided to satisfy the dust suppression demands at two locations. A northern water fill point will satisfy the demands from the northern MLA 50270 while a southern water fill point will satisfy the demands from the southern MLA 50254. 2.10.1.4
Overall Water Usage
The overall water usage includes the water demands for the potable supply usage, the CHPP make up water usage and the dust suppression usage. As previously noted, the overall water usage is calculated to vary depending on the mine staging year. This variation in water usage is primarily driven by the expected changes to the extent of surface areas requiring dust suppression. Table 5.9 presents the calculated overall water usage requirements for the operational life of the Project. The maximum water usage volume is calculated to be 3,566 Ml/a.
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Table 5.9
Elimatta Project
Calculated Overall Water Usage Demands for the Project
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2.10.2
Water Supply
The Project’s external water supply will be secured by a connection to the water distribution pipeline network owned by SunWater Limited (SunWater). Supply to the project site will be via a dedicated pipeline alignment adjacent to the WSL railway within the Rail and Services Corridor. Initially, the external water supply will be treated groundwater by-product resulting from dewatering operations associated with CSG extraction. Once construction of the proposed Nathan Dam is complete, the external supply will instead be sourced from Nathan Dam. Details of sourcing the external water supply will be the responsibility of the third party commercial water suppliers engaged by Taroom Coal. Water requirements will be entirely supplied by an external provider and delivered to dam RW1 located in MLA 50270 within the MIA. Based on continuing discussions with the water supplier, the external water supply is expected to have a Total Dissolved Solids in the order of 200 mg/L (EC of 300 µS/cm), which corresponds to the background Total Dissolved Solids in a number of surrounding water courses and water storages throughout the Fitzroy Basin area. The external supply water initially sourced from CSG dewatering will be treated by the supplier to a level which provides a maximum Total Dissolved Solids of 200 mg/L. This water quality will be suitable for use in the CHPP and for dust suppression on the mine site. To meet the potable demands, on-site treatment of the supply water will be required to achieve standards for human consumption. Potable water will be treated and monitored to ensure the Australian Drinking Water Guidelines (2011), endorsed by the National Health and Medical Research Council (NHMRC), are satisfied. However, these requirements are likely to be met by smaller filtration systems rather than larger Reverse Osmosis (RO) plants with dedicated waste streams. Detailed design of filter units will be determined as the Project nears development (when water quality details are better understood).
2.11
WATER STORAGE
The Project’s SWMS is a sequenced development consistent with the proposed mine staging. The staged development of the SWMS in MLA 50254 can be seen in the Mine Stage Plans presented in Section 2.2. The development of the SMWS is summarised in Table 5.10. An overview of the SWMS for the Project is provided in Figure 5.20. Details of the controlled release rates and triggers, as per the dam characteristics tables provided in the following sections, are only permitted if they satisfy the Final Model Water Conditions for Coal Mines in the Fitzroy Basin (EHP 2013).
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Table 5.10
Mine Year
Summary of Water Management System Changes Over the Mine Life
SWMS Requirements
1
Raw Water Dam RW1 to be constructed External water supply to be constructed North pit and east pit commence operations Environmental Dams EV1, EV2 and EV4 to be constructed Tailings dams TDN and TDNA to be constructed Sediment Dams SD1, SD2 and SD3 to be constructed
3
West pit commences operations Environmental Dam EV3 to be constructed Raw Water Dams RW2 and RW4 to be constructed
5
Raw Water Dam RW3 to be constructed
6
Tailings dam TDN reaches capacity and is decommissioned Fine tailings to be pumped to Tailings Dam TDNA
10
Tailings dam TDNA reaches capacity and is decommissioned North pit ceases mining operations Fine tailings to be pumped to TDP Environmental Dam EV1 is decommissioned
20
Raw Water Dam RW3 is decommissioned
30
Raw Water Dam RW2 is decommissioned Raw Water Dam RW4 is decommissioned
NB. The SWMS assumes the TSFs will be used in sequence (opposed to cycled, as proposed) so as to account for the lowest rate of water return from supernatant water back to the CHPP. This is considered the worst case scenario.
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Figure 5.20
Elimatta Project
Schematic of the Site Water Management System
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Mine Pit - E1 Mine Pit E1 is located in the north eastern portion of MLA 50254. The capacity of the pit floor sump in Pit E1 is 40 Ml and the pump dewatering rate for this sump is 200 Litres per second (L/s) for all mine staging years. At mine year 30, Pit E1 and Pit E2 join to become a final void located in the south east corner of MLA 50254. This transition is represented in the SWMS by retaining Pit E1, whereas Pit E2 becomes nonfunctional at mine year 30. The void characteristics of Mine Pit E1 are summarised in Table 5.11. Review of the model simulations undertaken as part of the development of the SWMS indicate that this pit did not overflow in any of the modelled climate simulations. Dewatering flows will report to the Environmental Dam EV2. Table 5.11 Void Characteristics of Mine Pit E1 Mine Staging Year
Pit Capacity (Ml)
Floor Sump Capacity (Ml)
Dewatering Rate (L/s)
Dewatering Destination
1
10518
40
200
Env. Dam EV2
3
10493
40
200
Env. Dam EV2
5
14578
40
200
Env. Dam EV2
8
29398
40
200
Env. Dam EV2
10
25496
40
200
Env. Dam EV2
15
20686
40
200
Env. Dam EV2
20
30524
40
200
Env. Dam EV2
25
66765
40
200
Env. Dam EV2
30
71810
40
200
Env. Dam EV2
Mine Pit - E2 Mine Pit E2 is located in the south eastern portion of MLA 50254. The capacity of the pit floor sump in Pit E2 is 50 Ml and the pump dewatering rate for this sump is 200 L/s for all mine staging years prior to year 30. At year 30, Pit E1 and Pit E2 join to become a final void located in the south east corner of MLA 50254. As previously detailed, this transition is represented in the SWMS by retaining Pit E1, whereas Pit E2 becomes non-functional at mine year 30. The void characteristics of Mine Pit E2 are summarised in Table 5.12. Review of the model simulations undertaken as part of the development of the SWMS indicate that this pit did not overflow in any of the modelled climate simulations. Dewatering flows will report to the Environmental Dam EV2.
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Table 5.12 Void Characteristics Mine Pit E2 Mine Staging Year
Pit Capacity (Ml)
Floor Sump Capacity (Ml)
Dewatering Rate (L/s)
Dewatering Destination
1
2961
50
200
Env. Dam EV2
3
13603
50
200
Env. Dam EV2
5
19233
50
200
Env. Dam EV2
8
22776
50
200
Env. Dam EV2
10
40480
50
200
Env. Dam EV2
15
59920
50
200
Env. Dam EV2
20
70950
50
200
Env. Dam EV2
25
77217
50
200
Env. Dam EV2
30
0
0
0
Env. Dam EV2
Mine Pit - N Mine Pit N is located in the northern portion of MLA 50254. The capacity of the pit floor sump in Pit N is 20 Ml and the pump dewatering rate for this sump is 200 L/s for all mine staging years up to year 10. After mine year 10, Pit N ceases to be an operational pit and it transitions to an in-pit TSF named Tailings Dam Pit (TDP). This transition is represented in the SWMS by TDP, which becomes functional after mine year 10, while Pit N becomes non-functional after mine year 10. The void characteristics of Mine Pit N are summarised in Table 5.13. Review of the model simulations undertaken as part of the development of the SWMS indicate that this pit did not overflow in any of the modelled climate simulations. Dewatering flows will report to the Environmental Dam EV1. Table 5.13 Void Characteristics Mine Pit N Mine Staging Year
Pit Capacity (Ml)
Floor Sump Capacity (Ml)
Dewatering Rate (L/s)
Dewatering Destination
1
737
20
200
Env. Dam EV1
3
737
20
200
Env. Dam EV1
5
6033
20
200
Env. Dam EV1
8
33873
20
200
Env. Dam EV1
10
517020
20
200
Env. Dam EV1
15
0
0
0
n/a
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Mine Staging Year
Pit Capacity (Ml)
Floor Sump Capacity (Ml)
Dewatering Rate (L/s)
Dewatering Destination
20
0
0
0
n/a
25
0
0
0
n/a
30
0
0
0
n/a
Mine Pit - W Mine Pit W is located in the south western portion of MLA 50254. The capacity of the pit floor sump in Pit W is 30 Ml and the pump dewatering rate for this sump is 200 L/s for all mine staging years after mine year 1, as this pit does not exist at mine year 1. The void characteristics of Mine Pit W are summarised in Table 5.14. Review of the model simulations undertaken as part of the development of the SWMS indicate that this pit did not overflow in any of the modelled climate simulations. Dewatering flows will report to the Environmental Dam EV3. Table 5.14 Void Characteristics Mine Pit W Mine Staging Year
Pit Capacity (Ml)
Floor Sump Capacity (Ml)
Dewatering Rate (L/s)
Dewatering Destination
1
0
0
0
n/a
3
11965
30
200
Env. Dam EV3
5
25377
30
200
Env. Dam EV3
8
21027
30
200
Env. Dam EV3
10
21008
30
200
Env. Dam EV3
15
28905
30
200
Env. Dam EV3
20
23295
30
200
Env. Dam EV3
25
23425
30
200
Env. Dam EV3
30
22963
30
200
Env. Dam EV3
Environmental Dam - EV1 Environmental Dam EV1 is located in the northern portion of MLA 50254 near to Pit N. Due to the predicted high salinity (median Total Dissolved Solids 3,700 mg/L) of the water stored in the dam, this dam will be classified with a significant hazard category in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). The capacity of Environmental Dam EV1 is 50 Ml for the initial mine staging. After mine year 10, Pit N will cease to be an operational pit and it will transition to become the TDP. Environmental Dam EV1
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will be decommissioned at that time. Controlled flow releases and uncontrolled overflows from this dam will be directed to the Horse Creek receiving waters. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: South water fill point demand
Priority 2 Destination: Controlled release to Horse Creek
The characteristics of Environmental Dam EV1 are summarised in Table 5.15. Table 5.15 Dam Characteristics EV1 Mine Staging Year
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
1-8
50
100
South Water Fill Point WFPS1
600
20
10 - 30
0
0
n/a
0
0
Environmental Dam – EV2 Environmental Dam EV2 is located in the north eastern portion of MLA 50254 near to Pit E1. Due to the predicted high salinity (median Total Dissolved Solids 5,605 mg/L) of the water stored in the dam, this dam will be classified with a significant hazard category in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). The capacity of Environmental Dam EV2 is 400 Ml for all mine staging years. Controlled flow releases and uncontrolled overflows from this dam will be directed to the Horse Creek receiving waters. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: South water fill point demand
Priority 2 Destination: Controlled release to Horse Creek
The characteristics of Environmental Dam EV2 are summarised in Table 5.16. Table 5.16 Dam Characteristics EV2 Mine Staging Year
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
1 - 30
600
100
South Water Fill Point (WFPS1)
600
0
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Environmental Dam - EV3 Environmental Dam EV3 is located in the south western portion of MLA 50254 near to Pit W1. Due to the predicted high salinity (median Total Dissolved Solids 4,767 mg/L) of the water stored in the dam, this dam will be classified with a significant hazard category in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). The capacity of Environmental Dam EV3 is 100 Ml for all mine staging years at mine year 3. Controlled flow releases and uncontrolled overflows from this dam will be directed to the Horse Creek receiving waters. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: South water fill point demand
Priority 2 Destination: Controlled release to Horse Creek
The characteristic of Environmental Dam EV3 are summarised in Table 5.17. Table 5.17 Dam Characteristics EV3 Mine Staging Year
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
1
0
0
n/a
0
0
3 - 30
200
100
South Water Fill Point (WFPS1)
600
0
Environmental Dam - EV4 Environmental Dam EV4 in the SWMS actually represents 5 smaller, linked dams located in the vicinity of the MIA in the southern portion of MLA 50270. These smaller dams include the stockpile west dam, the stockpile east dam, the MIA dam, the TLO dam and the CHPP dam. These environmental dams will receive contaminated runoff from the MIA catchments. Due to the predicted high salinity (median Total Dissolved Solids 3,964 mg/L) of the water stored, these dams will be classified with a significant hazard category in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). The combined capacities of the dams which form Environmental Dam EV4 are 380 Ml for all mine staging years. These dams have been represented as a single storage dam in the SWMS. Controlled flow releases and uncontrolled overflows from this dam will be directed to the Horse Creek receiving waters. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: CHPP water demand
Priority 2 Destination: North water fill point demand
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Priority 3 Destination: Controlled release to Horse Creek
The combined characteristics of the dams which form Environmental Dam EV4 are summarised in Table 5.18. Table 5.18 Dam Characteristics EV4 Mine Staging Year
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
1 - 30
380
100
North Water Fill Point (WFPN1)
600
20
Tailings Dam TDN Tailings Dam North (Dam TDN) is located in the mid portion of MLA 50270, west of the MIA. Due to the predicted high salinity (median Total Dissolved Solids 2,504 mg/L) of the water stored in the dam, this dam will be classified with a significant hazard category in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). The capacity of the Dam TDN starts at 13,060 Ml in mine year 1, but then progressively reduces due to filling with fine tailings. At mine year 5, the capacity of the dam is reduced to 3340 Ml and from that time on, fine tailings are no longer directed to this storage. The fine tailings are instead directed to the Dam TDNA. The gradual reduction in the capacity of Dam TDN has been accounted for in the SWMS. Emergency releases from this dam will be directed to the Horse Creek receiving waters. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: CHPP water demand
Priority 2 Destination: North water fill point demand
Priority 3 Destination: South water fill point demand
Priority 4 Destination: Controlled release to Horse Creek
Dam TDN is planned to receive fine tailings between mine years 1 and 6, at which stage this tailings dam will have reached its capacity. A depth of at least 3 m will be left between the final tailings surface and the dam’s crest level, to facilitate the capping and stabilisation of the captured tailings, prior to the end of mining. In the meantime, this 3 m depth will still be available for the capture of local catchment runoff in the dam. Cycling tailings disposal between TDN and TDNA is considered a viable alternative to improve fine rejects consolidation and extend the life of the surface TSFs. The scenario modelled in the SWMS is the worst case disposal method to model storage behaviour. Under a cycling disposal strategy, Dam TDN would reach capacity after nine years. The characteristics of Dam TDN are summarised in Table 5.19.
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Table 5.19 Dam Characteristics TDN Mine Staging Year
Dam Capacity (Ml)
1-5
8 - 30
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
100
CHPP
100
North Water Fill Point (WFPN1)
13060 100
South Water Fill Point (WFPS1)
100
CHPP
100
North Water Fill Point (WFPN1)
1650
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
0
0
0
0
South Water Fill Point (WFPS1)
100
Tailings Dam TDNA Tailings Dam North Alternative (Dam TDNA) is located in the northern portion of MLA 50270. Due to the predicted high salinity (median Total Dissolved Solids 2,504 mg/L) of the water stored in the dam, this dam will be classified with a significant hazard category in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). The capacity of the Dam TDNA starts at 11,770 Ml in mine year 1. Dam TDNA is planned to receive fine tailings between years 6 and 10, after Dam TDN has reached capacity. At mine year 10, the capacity of the dam is reduced to 2,450 Ml and from that time on, fine tailings are no longer directed to this storage. The fine tailings are instead directed to TDP. The gradual reduction in the capacity of Dam TDN has been accounted for in the SWMS. Emergency releases from this dam will be directed to the Horse Creek receiving waters. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: CHPP water demand
Priority 2 Destination: North water fill point demand
Priority 3 Destination: South water fill point demand
Priority 4 Destination: Controlled release to Horse Creek
A depth of at least 3 m will be left between the final tailings surface and the dam’s crest level, to facilitate the capping and stabilisation of the captured tailings, prior to the end of mining. In the meantime, this 3 m depth will still be available for the capture of local catchment runoff in the dam.
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Cycling tailings disposal between TDN and TDNA is considered a viable alternative to improve fine rejects consolidation and extend the life of the surface TSFs. The scenario modelled in the SWMS is the worst case disposal method to model storage behaviour. Under a cycling disposal strategy, Dam TDNA would reach capacity after 16.7 years. The characteristics of Dam TDNA are summarised in Table 5.20 Table 5.20 Dam Characteristics TDNA Mine Staging Year
1-8
10 - 30
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
100
CHPP
100
North Water Fill Point (WFPN1)
11,770 100
South Water Fill Point (WFPS1)
100
CHPP
100
North Water Fill Point (WFPN1)
2,450
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
0
0
0
0
South Water Fill Point (WFPS1)
100
Tailings Dam Pit (TDP) (In-pit TSF) As previously described Pit N transitions to an In-pit TSF after year 10, referred to as Tailings Dam Pit (TDP). TDP is located in the northern portion of MLA 50254. When Dam TDNA reaches capacity, fine tailings will then be pumped to the TDP. The TDP will then be able to accept fine tailings for the remainder of the mine’s life, up to mine year 30. This transition is represented in the SWMS by TDP, which becomes functional after mine year 10. The capacity of TDP is therefore zero for all mine years up to year 10. At mine year 10, the dam’s capacity is 51,700 Ml, which is then gradually reduced over time due to filling with fine tailings. At the end of mining in mine year 30, the capacity of the dam is reduced to 10,250 Ml. The gradual reduction in the capacity of this tailings dam is accounted for in the SWMS. Due to the predicted high salinity (median Total Dissolved Solids 3,010 mg/L) of the water stored in the dam, this dam will be classified with a significant hazard category in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). Emergency releases from this dam will be directed to the Horse Creek receiving waters. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: CHPP water demand
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Priority 2 Destination: North water fill point demand
Priority 3 Destination: South water fill point demand
Priority 4 Destination: Controlled release to Horse Creek
The characteristics of TDP are summarised in Table 5.21. Table 5.21 Dam Characteristics TDP Mine Staging Year
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
1-8
0
0
n/a
0
0
100
CHPP
100
North Water Fill Point (WFPN1)
0
0
10 - 30
51,700 – 10,250
South Water Fill Point (WFPS1)
100
Raw Water Dam - RW1 Raw Water Dam RW1 is located in the northern portion of MLA 50270, north of the MIA and east of the tailings dams. The capacity of Raw Water Dam RW1 is 200 Ml for all mine staging years. Controlled flow releases and uncontrolled overflows from this dam will be directed to the Horse Creek receiving waters. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: Potable demand
Priority 2 Destination: CHPP demand
Priority 3 Destination: North water fill point demand
Priority 4 Destination: South water fill point demand
Priority 5 Destination: Controlled release to Horse Creek
The characteristic of Raw Water Dam RW1 are summarised in Table 5.22.
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Table 5.22 Dam Characteristics RW1 Mine Staging Year
Dam Capacity (Ml)
1- 30
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
30
Potable Demand
100
CHPP Demand
100
North Water Fill Point (WFPN1)
100
South Water Fill Point (WFPS1)
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
0
0
200
Sediment Dam - SD1 Sediment Dam SD1 is located in the northern portion of MLA 50254, near Pit N. Based on the predicted low salinity (median Total Dissolved Solids 1,194 mg/L) of the water stored in the dam, this dam will be not be classified as a hazardous dam in accordance the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). The capacity of Sediment Dam SD1 is 100 Ml for all mine staging years. Controlled flow releases and uncontrolled overflows from this dam will be directed to the Horse Creek receiving waters. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: South water fill point demand
Priority 2 Destination: Controlled release to Horse Creek
The characteristic of Sediment Dam SD1 are summarised in Table 5.23. Table 5.23 Dam Characteristics SD1 Mine Staging Year
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
1- 30
100
100
South Water Fill Point (WFPS1)
0
0
Sediment Dam - SD2 Sediment Dam SD2 is located in the north eastern portion of MLA 50254, near Pit E1. Due to the
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predicted low salinity (median Total Dissolved Solids 1,566 mg/L) of the water stored in the dam, this dam will not be classified with a significant hazard category in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). The capacity of Sediment Dam SD2 is 250Ml for all mine staging years. Controlled flow releases and uncontrolled overflows from this dam will be directed to the Horse Creek receiving waters. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: South water fill point demand
Priority 2 Destination: Controlled release to Horse Creek
The characteristic of Sediment Dam SD2 are summarised in Table 5.24. Table 5.24 Dam Characteristics SD2 Mine Staging Year
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
1- 30
400
100
South Water Fill Point (WFPS1)
0
0
Sediment Dam - SD3 Sediment Dam SD3 is located in the south western portion of MLA 50254, near Pit W. Due to the predicted low salinity (median Total Dissolved Solids 1,220 mg/L) of the water stored in the dam, this dam will not be classified with a significant hazard category in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). The capacity of Sediment Dam SD3 is 125 Ml for all mine staging years. Controlled flow releases and uncontrolled overflows from this dam will be directed to the Horse Creek receiving waters. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: South water fill point demand
Priority 2 Destination: Controlled release to Horse Creek
The characteristic of Sediment Dam SD3 are summarised in Table 5.25. Table 5.25 Dam Characteristics SD3 Mine Staging Year
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
1- 30
200
100
South Water Fill Point (WFPS1)
0
0
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Raw Water Dam - RW2 Raw Water Dam RW2 is located in the south eastern portion of MLA 50254, east of Pit E2. This dam will be located upstream of the advancing high wall for mine Pit E2. The dam will only be required during mine years 3 to 25. Up to mine year 3, this natural catchment will freely drain to Horse Creek without any interference from the mine pits. However, at mine year 3, mine Pit E2 will effectively trap this catchment upstream of the pit’s high wall. Based on a review of the site’s natural topography, it is not practical to divert this catchment around the advancing mine Pit E2, due to the extensive earthworks required for such diversions. It is therefore proposed to construct a dam embankment across the gully upstream of the pit’s high wall and capture the runoff from the local catchment at this location. The boundary of this local catchment is largely contained within the boundary of Elimatta MLA 50254. Due to the eastern advance of the high wall for mine Pit E2, the size of this local catchment will gradually reduce with time, until it will completely disappear after mine year 25. In the final mine landform at mine year 30, the dam will not be required, as the local catchment will be largely comprised of rehabilitated worked spoil and the final surface levels will freely grade west towards the Horse Creek watercourse. The capacity of raw water dam RW2 varies from zero to 9620 Ml depending on the mine staging year. This dam is only required during mine years 5 to 25. Based on the predicted low salinity (median Total Dissolved Solids 629 mg/L) of the water stored in the dam, this dam will be not be classified as a hazardous dam in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). Controlled flow releases from this dam will be directed to Horse Creek receiving waters. Uncontrolled overflows from this dam will be directed to mine pit E2. However, the prioritised pumping order for this dam will be as follows:
Priority 1 Destination: South water fill point demand
Priority 2 Destination; Controlled release to Horse Creek
The characteristics of Raw Water Dam RW2 are summarised in Table 5.26. Table 5.26 Dam Characteristics RW2 Mine Staging Year
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
01
0
0
n/a
0
0
03 - 25
50
100
South Water Fill Point WFPS1
0
0
30
0
0
n/a
0
0
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Raw Water Dam - RW3 Raw Water Dam RW3 is located in the north eastern portion of MLA 50254, east of pit E1. This dam will be located upstream of the advancing high wall for mine Pit E1. The dam will only be required during mine years 5 to 15. Up to mine year 5, this natural catchment will freely drain to Horse Creek without any interference from the mine pits. However, at mine year 5, mine Pit E1 will effectively trap this catchment upstream of the pit’s high wall. Based on a review of the site’s natural topography, it is not practical to divert this catchment around the advancing mine Pit E1, due to the extensive earthworks required for such diversions. It is therefore proposed to construct a dam embankment across the gully upstream of the pit’s high wall and capture the runoff from the local catchment at this location. The boundary of this local catchment is largely contained within the boundary of Elimatta MLA 50254. Due to the eastern advance of the high wall for mine Pit E1, the size of this local catchment will gradually reduce with time, until it will completely disappear after mine year 15. After mine year 15 the dam will not be required, as the local catchment will be largely comprised of rehabilitated worked spoil and the final surface levels will freely grade west towards the Horse Creek watercourse. The capacity of raw water dam RW3 varies from zero to 140 Ml depending on the mine staging year. This dam is only required during mine years 5 to 15. Based on the predicted low salinity (median Total Dissolved Solids 326 mg/L) of the water stored in the dam, this dam will be not be classified as a hazardous dam in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). Controlled flow releases from this dam will not be permitted. Uncontrolled overflows from this dam will be directed to mine Pit E1. The characteristic of Raw Water Dam RW3 are summarised in Table 5.27. Table 5.27 Dam Characteristics RW3 Mine Staging Year
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
1-3
0
0
n/a
0
0
5 - 15
50
100
Raw Water Dam RW2
0
0
20 - 30
0
0
n/a
0
0
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Raw Water Dam (RW4) Raw water dam RW4 is located in the south western portion of MLA 50254, west of Pit W. This dam will be located upstream of the advancing high wall for mine Pit W. The dam will only be required during mine years 3 to 20. Up to mine year 3, this natural catchment will freely drain to Horse Creek without any interference from the mine pits. However, at mine year 3, mine Pit W will effectively trap this catchment upstream of the pit’s high wall. Based on a review of the site’s natural topography, it is not practical to divert this catchment around the advancing mine Pit W, due to the extensive earthworks required for such diversions. It is therefore proposed to construct a dam embankment across the gully upstream of the pit’s high wall and capture the runoff from the local catchment at this location. The boundary of this local catchment is largely contained within the boundary of Elimatta MLA 50254. Due to the western advance of the high wall for mine Pit W, the size of this local catchment will gradually reduce with time, until it will completely disappear after mine year 20. In the final mine landform at mine year 30, the dam will not be required, as the local catchment will be largely comprised of rehabilitated worked spoil and the final surface levels will freely grade east towards the Horse Creek watercourse. The capacity of raw water dam RW4 varies from zero to 140 Ml depending on the mine staging year. This dam is only required during mine years 3 to 20. Based on the predicted low salinity (median Total Dissolved Solids 321 mg/L) of the water stored in the dam, this dam will be not be classified as a hazardous dam, in accordance with the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). Controlled flow releases from this dam will not be permitted. Uncontrolled overflows from this dam will be directed to mine pit W. The characteristic of Raw Water Dam RW4 are summarised in Table 5.28. Table 5.28 Dam Characteristics RW4 Mine Staging Year
Dam Capacity (Ml)
Transfer Pumping Rate (L/s)
Transfer Pumping Destination
Controlled Release Rate (L/s)
Controlled Release Trigger Volume (%)
01
0
0
n/a
0
0
03 - 15
50
100
Raw Water Dam RW2
0
0
20 - 30
0
0
n/a
0
0
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2.12
WATER DISCHARGE
It is intended that controlled releases from water storage dams will be allowed to discharge into the Horse Creek receiving waters. Controlled releases would only be allowed provided that they satisfy EHP’s flow release criteria, stipulated in the Model Water Conditions for Coal Mines in the Fitzroy Basin (EHP 2013). The flow release criteria are based on a combination of minimum passing flow rate and water quality criteria. Based on the intent of the Fitzroy Flow Release Manual, the following flow triggers have been determined for the Horse Creek receiving waters.
2.12.1
No / Low Flow Release Trigger
The no/low flow trigger (good quality mine affected water) for Horse Creek has been determined as follows:
Release is only permitted when flows in the Horse Creek receiving waters are on the tail end of a flow event. That is, release is permitted only following a flow in the creek which has risen to a level above a specified event flow trigger and has then fallen below the flow trigger again. This scenario will then commence a release window of 28 days during which the release of good quality mine water can occur.
From the assessment of EC versus flow interaction, the adopted flow event trigger for Horse 3 Creek corresponds to the 50 percentile daily flow rate, which is 0.05 m /s (5 ML/day) immediately upstream of the mine site.
An event flow trigger value of 0.05 m /s will be impossible to measure with a stream flow gauge constructed on the mobile creek bed of Horse Creek. A more realistic event flow trigger 3 of 1.0 m /s has therefore been adopted as being appropriate for the Horse Creek watercourse.
The end of pipe water quality of the mine water must be less than or equal to the long term th th background reference 75 /80 percentile EC in the receiving waters. The 80 percentile EC for the Dawson River was calculated as 380 µs/cm (TDS 250 mg/L). This value was considered appropriate for the Horse Creek watercourse.
The duration of the release is to be limited. In a dry ephemeral watercourse, the duration of the release must not exceed 28 days after the flow in the receiving waters falls below the event flow trigger.
No volume/rate limits have been specified for the no/low flow release trigger.
2.12.2
3
Medium Flow Release Trigger
The medium flow trigger (medium quality mine affected water) for Horse Creek has been determined as follows:
Release is only permitted when flow in the Horse Creek receiving waters is above a specified flow trigger, which must be representative of event flow and be above the base/low flow.
From the assessment of EC versus flow interaction, the adopted flow event trigger for Horse 3 Creek corresponds to the 50 percentile daily flow rate, which is 0.05 m /s (5 ML/day)
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immediately upstream of the mine site.
An event flow trigger value of 0.05 m /s will be impossible to measure with a stream flow gauge constructed on the mobile creek bed of Horse Creek. A more realistic event flow trigger 3 of 1.0 m /s has therefore been adopted as being appropriate for the Horse Creek watercourse.
Two medium flow release triggers have been specified. The first release trigger (Med1) 3 corresponds to a minimum event flow trigger of 1.0 m /s, plus a maximum end of pipe water quality (EC) of 1,500 µs/cm (1,000 mg/L) for the mine affected water to be released. The 3 corresponding maximum release rate for the Med1 release trigger is 0.6 m /s. This is based on: Q trigger x (EC instream – EC trigger) / (EC EOP – EC instream.
The second release trigger (Med2) corresponds to a minimum event flow trigger of 2.0 m /s, plus a maximum end of pipe water quality (EC) of 3,500 µs/cm (2,345 mg/L) for the mine affected water to be released. The corresponding maximum release rate for the Med2 release 3 trigger is 0.4 m /s. This is based on Q trigger x (EC instream – EC trigger) / (EC EOP – EC instream).
The design dilution/maximum release rate should be based on a site-specific risk assessment. The maximum release rate should be designed to achieve an in-stream EC based on mid catchment (Zone 2) of EC instream = 700 µs/cm.
2.12.3
3
3
High Flow Release Trigger
The high flow trigger (poorer quality mine affected water) for Horse Creek has been determined as follows:
Release is only permitted when flow in the Horse Creek receiving waters is above a specified high flow trigger, which must be representative of high event flow and must be above the medium flow.
The 90 percentile flow rate in Horse Creek has been adopted for the high flow trigger. The 90 3 percentile flow rate for Horse Creek was calculated as 4.0 m /s (346 ML/d).
The high flow release trigger corresponds to a minimum event flow trigger of 4.0 m /s, plus a maximum end of pipe water quality (EC) of 10,000 µs/cm (6700 mg/L) for the mine affected water to be released. The corresponding maximum release rate for the high flow release 3 trigger is 0.2 m /s, based on Q trigger x (EC instream – EC trigger) / (EC EOP – EC instream).
The design dilution/maximum release rate should be based on a site-specific risk assessment. The maximum release rate should be designed to achieve an in-stream EC based on mid catchment (Zone 2) of EC in stream = 700 µs/cm
3
2.13
SITE WATER MANAGEMENT
2.13.1
Water Management Strategy
The overarching philosophy of the water management strategy prepared for the Project is to minimise any adverse impacts to the surrounding environment throughout the entire life of the mine. This goal is to be achieved by the adoption of a comprehensive best practice approach to the management of all water over the Elimatta Project site, comprising MLA 50254, MLA 50270 and MLA 50271.
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2.13.1.1
Water Management Strategies over the Southern MLA 50254
Over the southern MLA 50254, where all of the mining will actually occur, the following best practice management approaches have been incorporated into the water management strategy: 1.
Minimise the impact on downstream watercourses by limiting the area to be disturbed at any one time. This will be achieved by careful mine stage planning, which minimises the footprint of the overall disturbed landform and in particular the footprint of the operating pits.
2.
Capture all saline groundwater intercepted by the mine pits and prevent the unauthorised discharge of saline water into the Horse Creek receiving waters. In particular, 3 large environmental dams will be located throughout the southern Elimatta MLA 50254, to receive saline groundwater pumped from the operating mine pits.
3.
Provision of separate clean water and contaminated water drainage systems to minimise the overall volume of contaminated water on the Project site. Provision of diversion drains and bunds to prevent clean water from draining into hazardous dams and sediment dams, thereby reducing the size of dams required on site.
4.
Progressive and timing reinstatement of the disturbed landform. As the front of the mined pit advances, waste spoil overburden material and coarse rejects will be progressively placed back into the already worked pit void. The landforms of the spoil material placed back into the pit void will be shaped and reinstated in a timely manner and the batter slopes of all disturbed surfaces will be worked along the contour to minimise the likelihood of scour down the batter face.
5.
The finished surface slopes of the re-shaped landforms will be graded to ultimately allow for natural runoff to freely drain into the Horse Creek receiving waters.
6.
Prior to the establishment of a stable vegetative cover, runoff from the re-graded, but disturbed spoil landforms will be intercepted by localised diversion drains and runoff will be directed into sediment basins, to prevent the discharge of sediment laden turbid waters into the Horse Creek receiving waters. In particular, several sediment dams will be located throughout the southern Elimatta MLA 50254, to capture sediment laden runoff from proposed spoil dumps adjacent to the north pit, the west pit and the east pit.
7.
Rehabilitation and revegetation of disturbed landforms will be undertaken as soon as is practical. Once landforms have developed a stable vegetative cover, the localised diversion channels can be decommissioned and runoff from the rehabilitated catchment slopes will be able to freely drain into the Horse Creek watercourse.
8.
Minimise the risk of discharge of highly saline waters to the Horse Creek receiving waters by only permitting the release of water stored in the environmental dams, the sediment dams and the raw water dams throughout the Elimatta MLAs, in accordance with EHP (2013) model conditions for the discharge of mine affected water from coal mines in the Fitzroy Basin.
9.
Minimise the risk of discharge of highly saline waters to the Horse Creek receiving waters by appropriately sizing the environmental dams, sediment dams and raw water dams throughout the Elimatta MLAs, to strictly limit the frequency and magnitude of uncontrolled overflows from the dams into the receiving waters.
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10.
On site re-use and re-cycling of water shall be occur as standard operating procedure. The water captured in the Elimatta water management system shall be used to satisfy on site water demands arising due to potable needs, coal washing needs in the CHPP and for dust suppression needs. Use of the captured on site water shall be prioritised such that the higher salinity water is used in the first instance. This will reduce the likelihood of uncontrolled overflows of highly saline water to the Horse Creek receiving waters, by lowering stored water levels in the various storage dams.
11.
Interference of natural catchments shall be avoided at all times. However, in some cases where natural catchments shall be unavoidably affected by the proposed mining activities and where the catchment boundaries are largely contained within the extent of the MLAs, interception of those natural catchments will be permitted. In such instances, the duration of the interference shall be minimised to reduce to enable the timely restoration of the natural drainage behaviour.
2.13.1.2
Water Management Strategy over the Northern MLAs 50270 and 50271
Over the northern MLA 50270, where all of the mine infrastructure will be located, the following best practice management approaches have been incorporated into the water management strategy: 1.
Capture all contaminated runoff associated with the MIA and prevent the unauthorised discharge of saline water into the Horse Creek receiving waters. In particular, several environmental dams will be located in MLA 50270, to capture saline runoff from the MIA catchments.
2.
Ensure that the tailings dams are appropriately sized to accommodate the expected volume of fine tailings output from the CHPP and to also minimise the frequency and magnitude of uncontrolled overflows into the Horse Creek receiving waters, at all times throughout the life of the tailings dams.
3.
Ensure that sediment dams are provided along the route of the haul road linking the southern MLA with northern MLA, to prevent the discharge of sediment laden runoff from disturbed areas into the Horse Creek receiving waters. Road runoff may also pick up spilled coal product along the route of the transport corridor.
2.13.1.3
Expected Approval Requirements
Several of the water storages will be considered hazardous under the Manual for Assessing Hazard Categories and Hydraulic Performance of Dams (DERM 2012). Dams which are assessed as having a hazard category of significant or high are regulated under the EP Act, which is administered by EHP. In addition, dams that are considered referable dams are regulated under the Water Supply (Safety and Reliability) Act 2008 which is administered by Department of Energy and Water Supply (DEWS). The Water Resource (Fitzroy Basin) Plan 2011 is also relevant to the development of the SWMS; however, Taroom Coal is not seeking a water allocation from the Fitzroy Basin under the Water Resource (Fitzroy Basin) Plan 2011. Taroom Coal will not require a water allocation when obtaining an external supply through an agreement with SunWater. The ownership of the water entitlement and the associated rights to supply remain with SunWater. However, a Water Licence under the Water Act 2000 will be required to take or interfere with groundwater for pit dewatering purposes which are integral to the safe operation of the Project. The development of the SWMS will impact upon overland flow in the Project area in an effort to separate clean and dirty water catchments and contain dirty water. Overland flow is covered in the
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Water Resource (Fitzroy Basin) Plan 2011, as follows:
Overland flow water other than water in a spring connected to – o
Artesian water; or
o
Subartesian water connected to artesian water.
For the Elimatta SWMS, the taking of overland flow water is limited to Raw Water Dams RW2, RW3 and RW4. The catchments draining to these dams are generally limited in size to the boundaries of the MLAs. These dams are required to prevent external catchment runoff from upstream of the pit high walls from overflowing into the operating pits. Individually, these dams have been designed to contain no more than 50 ML and as such do not trigger the taking of overland flow criteria in in the Water Resource (Fitzroy Basin) Plan 2011. These dams will ultimately be decommissioned when the mining progresses upstream in the catchments and eventually eliminates the catchments altogether.
2.13.2
Stormwater drainage
2.13.2.1
Operational Stormwater Infrastructure
Clean water diversion drains will be required surrounding disturbance areas to divert clean stormwater around sources of potential contamination. Figure 5.21 shows the standard design dimensions for the clean water diversion banks and channels to be constructed on the Project. Diversion channels will be sized in accordance with dimensions of the up slope catchment. Following significant rainfall events, all diversion works should be checked to ensure the structures have been able to sustain flow velocities without causing significant scour.
Figure 5.21
Conceptual Design of Clean Water Diversion Drain
Contaminated water will be pumped and diverted into the various water storages as outlined in Section 2.11. In summary:
Pit sumps will collect contaminated pit water and groundwater inflows, these sumps are then dewatered to local Environmental Dams EV1, EV2 and EV3 adjacent to the pit areas for the duration of pit operations;
Potentially contaminated catchment areas within the MIA report to the five environmental dams within the MIA and TLO footprint which form Environmental Dam EV4 for the
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duration of the mine life;
Sediment and runoff from the out-of-pit spoil dump in the north of MLA 50254 is captured in Sediment Dam SD1 for the duration of the mine life;
Sediment and runoff from the initial box cut area and subsequent in-pit spoil dump in the northeast of MLA 50254 is captured in Sediment Dam SD2 for the duration of the mine life;
Sediment and runoff from the out-of-pit spoil dump in the southwest of MLA 50254 is captured in Sediment Dam SD3 for the duration of the mine life;
Raw Water Dam RW2 consists of an embankment dam in the south of MLA 50254 to capture clean water in advance of the pit highwall for years 5 to 25 of the mine life;
Raw Water Dam RW3 consists of an embankment dam in the northeast of MLA 50254 to capture clean water in advance of the pit highwall for years 5 to 15 of the mine life; and
Raw Water Dam RW4 consists of an embankment dam in the south western portion of MLA 50254 to capture clean water in advance of the pit highwall for years 5 to 25 of the mine life.
In essence, the sediment dams (SD1, SD2 and SD3) may comprise a series of linked sediment ponds sized and operated as per the specifications detailed in Section 2.11. These ponds are shown in the Mine Stage Plans provided in Section 2.4. This approach will ensure the capture of all potentially contaminated water in a system which is suited to the evolving landform topography throughout the life of the mine. Stormwater diversion and containment infrastructure for MLA 50254 as described above is shown in Figure 5.6 – Figure 5.15. Stormwater diversion and containment infrastructure for MLA 50270 is shown in the following figures. Figure 5.22 provides an overview of the MIA environmental dam network, known collectively as Environmental Dam EV4. This arrangement details the separation of clean and dirty water catchments and shows the likely path of diverted water flows. Figure 5.23 demonstrates the layout of the clean water diversion drain proposed to channel stormwater flows around Dam TDN. Figure 5.24 shows similar design details of Dam TDNA. Figure 5.25 shows the catchment areas which drain through the Infrastructure MLA 50270. Ultimately, these catchment areas drain under the train load out facility conveyor alignment and into Horse Creek. Allowances will be made during the construction of infrastructure alignments to provide for sufficient drainage capacity through culverts so as to maintain infrastructure integrity and minimise potential environmental impacts.
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N.B. Figure shows historic alignment of proposed Haul Road prior to the amendment of MLA 50270 boundary.
Figure 5.22 MIA Water Management Infrastructure
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Figure 5.23 Northern TSF (TDN) Water Management Infrastructure
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Figure 5.24 Northern Alternative TSF (TDNA) Water Management Infrastructure
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N.B. Figure shows historic alignment of proposed Haul Road prior to the amendment of MLA 50270 boundary
Figure 5.25 Infrastructure MLA Drainage Catchments
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2.14
RAIL & SERVICES CORRIDOR WATER MANAGEMENT
The following water management infrastructure is proposed in order for the development of the WSL. As these activities will be undertaken outside of the MLA area, and will be carried out within a watercourse, lake or spring they will likely require authorisation via a Riverine Protection Permit under the Water Act 2000.
2.14.1
Major Crossings
Four major waterways impact the alignment of the proposed Rail and Services Corridor: Juandah Creek, Mud Creek, Spring Creek and either Horse Creek (south) or Horse Creek (north). Hydraulic modelling was undertaken to determine the flood extents and levels to inform bridge designs at waterway crossings. A number of potential bridge design options were collated and the afflux of the bridging structure on the flood levels was determined. Detailed bridge designs have not been completed, but the bridge design parameters adopted for the purpose of the hydraulic assessment are as follows:
Bridge spans of 25 m;
Singular piers with diameters of 1.2 m;
Bridge width of 4 m;
Abutment slopes of 1.5:1; and
Bridge soffit to be a minimum of 600 mm above the 1,000 year ARI flood level.
To determine requirements of bridge design, one-dimensional modelling was used for Spring Creek, while two-dimensional modelling was used for all other creeks. Based on the results of the modelled scenarios, the following recommendations were made for each crossing:
A single 200 m wide opening (225 m long bridge) will be used for Juandah Creek, based on downstream afflux and velocities. This option has an afflux of 40 mm approximately 1 km upstream of the rail alignment in a 100 year event;
A 150 m wide opening (175 m long bridge) with a culvert (1950 mm diameter of equivalent) on the tributary will be used for Mud Creek. A 100 year ARI has no afflux 1 km upstream of the rail alignment for this option, indicating that further reductions to the bridge span could be considered;
Multiple openings are required for Horse Creek (south) due to the large proportion of conveyance outside of the main channel. Two 150 m wide openings (175 m long bridges) and one 100 m opening over the road (125 m long bridge) will be used for the southern alignment. For a 100 year event, this option has an afflux of 20 mm approximately 1 km upstream of the rail alignment;
For Horse Creek (north), a 150 m wide opening (175 m long bridge) and one 75 m opening over the road (100 m long bridge) will be used. A 100 year ARI has an afflux of 69 mm approximately 1 km upstream of the rail alignment; and
A 50 m wide opening (75 m bridge) will be used for Spring Creek. In a 100 year ARI, this
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option has an afflux of 50 mm approximately 150 m upstream of the rail alignment.
2.14.2
Minor Crossings
To assess minor crossings not subject to hydraulic modelling, a culvert design spreadsheet based on the methodology provided in Waterway Design (AUSTROADS 1994) was used to determine peak design flows by probabilistic rational method. Pipe culverts have been designed, where possible, with a minimum 1.0 m cover for improved constructability, and a water level freeboard of 600 mm to the top of the rail. Culvert design also includes a minimum slope of 0.5% to ensure adequate drainage and self-cleansing velocity, and a minimum diameter of 900 mm. A summary of culvert sizes at each location is provided in Table 5.29 and a typical cross-section is shown in Figure 5.26. Table 5.29 Culvert sizes at each location Culvert ID
Culvert Size (mm)
Number of Culverts
Culvert Length
CD0007
900
5
15
CD0041
1650
4
29
CD0103
1800
5
30
CD0129
1950
1
31
CD0167
900
6
18
CD0219
1950
2
52
CD0264
1800
2
55
CD0317
900
6
24
CD0360
1200
4
22
CD0505
900
11
12
CD0556
1950
1
31
CD0656
900
12
16
CD0807
1050
4
34
CD0823
900
7
18
CD0950
1800
1
41
CD1012
900
5
14
CD1050
900
2
27
CD1230
1200
5
26
CD1348
1050
6
24
CD1378
1950
1
38
CD1446
1800
2
55
CD2024
1500
2
32
CD2051
900
3
15
CD2080
1500
1
40
CD2137
2100
1
56
CD2225
1650
1
51
CD2410
1650
2
50
CD2450
1500
1
48
CD2573
2100
1
57
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Culvert ID
Culvert Size (mm)
Number of Culverts
Culvert Length
CD2795
1950
1
47
CD2826
2100
2
59
CD2968
1950
2
58
CD2983N
2100
3
101
CD3050N
1350
5
31
CD3223N
1350
2
30
CD3299N
1200
1
43
CD3317N
900
1
45
CD3709N
1350
2
30
CD3952N
1200
1
61
CD4048N
1200
1
22
CD2983S
1350
3
101
CD3050S
1350
5
31
CD3364S
1350
3
73
CD3609S
900
1
48
CD6868S
900
1
53
Figure 5.26 Typical culvert outlet cross-section
2.15
ROAD DIVERSION AND CONSTRUCTION
Mine roads will be specific to the operation of the project and closed to public access. These roads will occur entirely within the boundaries of the MLAs and are described in Section 2.15.1. Public roads, including those within the boundaries of the Project, will be temporarily closed, diverted or upgraded as detailed in Section 2.15.2.
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2.15.1
Mine Roads
As part of the construction phase, road developments within the MLA will occur to support the proposed operations. The construction of mine roads will involve the formation of the haul road, through MLA 50271, for ROM transport from the pit area to the CHPP. The haul road will be approximately 4.04 km long and built in accordance with industry standards at a width of 27 m with earth side bunds appropriate for the proposed haul truck specifications. Developments during the construction phase will also involve the establishment of mine service roads. These roads will be segregated, so as to separate vehicle types, and built according to the specifications required for individual vehicles (light vs. heavy). Mine service roads will serve primarily for the movement of light vehicles between mine infrastructure areas and will be designed in accordance with Austroads’ Guide to Road Design (Austroads 2010). The mine service road network will also include the access road from Perretts Road to the MIA area. Typically, mine roads are usually for mine use only and only available for general use under defined circumstances. All of the internal mine roads will be constructed during Year -1 for commissioning prior to the commencement of the operational phase.
2.15.2
Public Roads
2.15.2.1
Mining Lease Areas
There are a number of formed roads across and around the proposed mine under the control of Western Downs Regional Council (WDRC) that provide a service to local traffic. The development of the proposed mine will result in a number of temporary road closures, new sections of road and road relocations within and adjacent to the MLA areas. The purpose of the public road openings and closures is to allow mine operations to occur and provide safe alternative public traffic movement for road registrable vehicles with minimum disruption to existing patterns of movement. Roads which are directly affected by the project are highlighted in Figure 5.27 and listed below:
The existing Perretts Road alignment, between Bundi Road and Ryals Road, runs through the middle of the proposed pit area in MLA 50254. This section of Perretts Road is to be temporarily relocated to the east, outside of the MLA area;
Part of Ryals Road across Horse Creek to Perretts Road is to be upgraded;
Part of the existing alignment of Perretts Road between Ryals Road and Cattle Camp Road, in the vicinity of MLA 50270, is to be upgraded;
Cattle Camp Road is to be upgraded to provide access to the Accommodation Village and service public access from Perretts Road to the western side of the MLA areas;
Goldens Road, along the southern boundary of MLA 50270, will be closed to facilitate development of the mine haul road; and
A section of new road, linking Goldens Road to Cattle Camp Road, will be developed to maintain access between the western side of the MLA areas and Perretts Road.
The timing of the public road relocations and closures is dependent upon design and construction
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approval from the WDRC. It is envisaged that all public road works will be constructed during Year -1 for commissioning prior to the commencement of the operational phase of the Project.
Figure 5.27 2.15.2.2
Proposed Public Roads Closures and Upgrades
Rail and Services Corridor
Construction of the WSL and associated infrastructure, including access roads, will involve alterations to road infrastructure, including one State-controlled road crossing (Leichhardt Highway) and five local road crossings under WDRC jurisdiction. Road crossings required for the preferred rail alignment are
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detailed in Table 5.30. Detailed crossing locations however are subject to further rail alignment development and approvals from the DTMR and WDRC. Table 5.30 Public Road Crossings Approximate Chainage (m)
Location
Treatment
Comments
750
Nathan Road
Road over rail
Leichhardt Highway and Booral Road / No.1 Lane
7200
Road over rail
20000
Grosmont Road
29000
Kabunga Road
35200
Perretts Road
Road over rail Public level crossing
Road over rail
Alignment is in cut of 5.0 m; Road realignment is required to achieve clearances and improve skew angles; Sealed pavement. Alignment is in cut of 2.0 m; Leichhardt Hwy bridge approach works are required to achieve clearances; Sealed pavement. Alignment is in cut of approximately 5.7 m; Sealed pavement. Crossing location to be confirmed in future design stages; Un-sealed pavement. Alternative crossing location to be confirmed in future design stages; Sealed pavement.
Further alterations include stock route crossings and occupational (private) crossings. The number of stock and occupational crossings is subject to ongoing consultation with landowners and relevant stakeholders. Stock routes ordinarily used for travelling stock or declared to be a stock route under regulation are shown in Table 5.31, along with the suggested treatment. Table 5.31 Stock Route Crossings
Approximate Chainage (m)
Treatment
Comments/Use
10215
Level crossing
Vehicle and machinery movements
10500
Stock crossing*
Stock movements, including a stock route diversion
Note – * denotes grade separated Access for land owners will be maintained during construction and operation phases of the Project and will be negotiated on a case by case basis. Where allowable, crossings will be constructed in the same location as the existing access, however, where it is not safe to do so, an alternative location will be considered. Where landscape conditions allow, occupational or private stock crossings will also be provided at rail level. The timing of public road rail crossing construction will vary but it is likely that construction will take approximately 6-9 months from commencement to completion during the initial stages of the construction period. Due to the interaction with rail alignment and crossings, it is expected work on
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individual crossings will be staged as required.
2.16
POWER SUPPLY
The local Ergon power network around the Project area is typically a rural Single Wire Earth return network which does not have capacity to deal with the power loads required for construction or operation. Consequently, onsite power generation, through the use of diesel mobile generators, will be utilised during the early construction phase of the Project. This will be replaced with a permanent grid connection to either the Wandoan or Wandoan South substations as soon as possible within the construction stage.
2.16.1
Construction Power Demand
Power will be required at the administration/construction offices, accommodation village and sewage treatment plants. The maximum energy demands required during the construction phase are calculated based on the following assumptions:
Administration/construction offices located at the MLA areas and on the Rail and Services 2 Corridor 75 volt-ampere (VA) per square metre (m );
Accommodation village, 2.5 kiloVolt-Amperes (kVA) per head (560 x 2.5 – 1400 kVA); and,
Sewage treatment plant 48 kVA.
Based on this, it is envisaged that the energy consumption per month will be approximately 759 MegaWatt hours (MWh) during construction. Initially diesel generators will be utilised during the early construction period as the major power source. Some of these generators will remain on site after mains power supply has been connected and will provide a backup power supply in the event of a failure of the grid supply. These back up units will power emergency service requirements only and will not have sufficient capacity to maintain production operations.
2.16.2
Operations Power Demand
The peak permanent power demand during operational periods is approximately 13,550 kiloWatt (kW) with an average of 11,590 kW. Based on these figures the annual energy usage has been calculated to be 75,000 MWh. Determination of overall site maximum demand is calculated by looking at the accommodation village, CHPP, MIA, and environmental dam loads to appropriately size the substation transformers. Load sources and operating hours are detailed in Table 5.32.
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Table 5.32 Load Sources and Operating Hours
Load Source
Peak Load (kW)
Avg. Load (kW)
2500
Estimated Annual Usage (hours) Year 1
Year 2
Year 3
Year 4
Year 5
Year 6
Year 7EOM
2500
6570
8760
8760
8760
8760
8760
8760
50
50
6570
8760
8760
8760
8760
8760
8760
CHPP
9800
7840
0
0
4100
6400
6300
6600
6100
Train Load Out
1200
1200
0
0
1155
1803
1775
1859
1718
Total
13550
11590
-
-
-
-
-
-
-
Accomm. Village Water Management
2.16.3
Grid Connection Infrastructure
Taroom Coal has made an application with Ergon Energy Limited (Ergon) for a connection to infrastructure in the Wandoan area to provide the Project’s energy requirements. Powerlink Queensland and Ergon are developing major power infrastructure in the Wandoan South area to service CSG and coal resource development. Elimatta has grid connection options to Ergon substations located at Wandoan (via the Rail and Services Corridor) and Wandoan South (via proposed corridors under consideration by Ergon). The connection routes from either sub-station location are still being investigated by Ergon. The corridor and infrastructure will be developed and operated by Ergon to a connection point on the mine site. Approvals associated with the development of this infrastructure will be the responsibility of the service provider. The permanent power supply to the Project will be via a 66 kV high voltage connection. The proposed electrical system in the operational phase will include a 66/11 kV mine substation which will supply:
11 kV CHPP switch-room (prefabricated offsite);
1 MVA (11/0.433 kV) MIA kiosk substation;
100 kVA (11/0.433 kV) pole top transformer for the Environmental Dam; and
3 x 500 kVA (11/0.433 kV) Accommodation Village kiosk substations.
Two 20 MVA transformers will be installed in the mine substation to allow for n-1 redundancy and maintenance of transformers while the mine is still operational. In order to supply the Project with a permanent power connection there is considerable infrastructure required as described below:
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Mine Substation Infrastructure:
Earthworks and gravel access roads;
Earth grid, electrodes, and equipotential bonding;
Lightning protection system;
Plinths, bunding and foundations;
Compound fencing;
Area lighting;
2 off 15 MVA 66/11 kV transformers (operating in standby/duty configuration) including neutral earthing resistors (NERS);
66 kV air-insulated switch (AIS) gear;
11 kV AIS gear;
11 kV outdoor bus work; and
Single control room housing feeder protection, transformer protection and local station backup supplies.
CHPP Switch Room Infrastructure:
Earthworks and gravel access roads;
Earth grid, electrodes, and equipotential bonding;
Lightning protection system;
Plinths, bunding and foundations;
Area lighting; and
11 kV ground-insulated switchroom and switchgear, housing feeder protection, transfer protection and local station back-up supplies.
MIA infrastructure:
1 off kiosk substations (11/0.433 kV, 1000 kV, 11 kV ring main unit (RMU) included);
Plinths, bunding and foundations;
Earth grid and electrodes;
Switchboard plinths;
Switch boards (From 3B, 50 kA, IP 66); and
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Cabling (switchboard - kiosk).
Environment Dam Infrastructure:
1 off pole top transformer (11/0.433 kV, 100 kVA);
Foundations;
Earth grid and electrodes;
Switchboards/Motor Control Centre (MCC); and
Cabling.
Accommodation Village Infrastructure:
3 off kiosk substations (11/0.433 kV, 500 kVA, 11 kV RMU included);
Plinths, bunding and foundations;
Earth grid and electrodes;
Switchboard plinths;
Switch boards (Form 3B, 50 kA, IP 66); and
Cabling (switchboard-kiosk).
11kV reticulation infrastructure:
11kV overhead/underground reticulation connecting mine substation to: o
MIA kiosk;
o
Accommodation village;
o
CHPP switch-room; and
o
Train Load Out.
WSL Corridor:
Power supply for all signalling, telecommunications and train control will be sourced from the nearest power utility.
Way side detectors for dragging equipment hotboxes etc. will be solar/battery operated.
2.17
FUEL AND HYDROCARBON STORAGE
Fuel and oil will be stored on site within bulk storages and will be used to operate various fixed plant and mobile equipment. The types and amounts of fuel to be stored onsite will include;
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Fuel:
7 x 150,000 L horizontal diesel tanks
1 x 35,000 L hydraulic oil
1 x 35,000 L engine oil
1 x 35,000 L waste oil
1 x 20,000 L transmission oil
1 x 15,000 L gear oil
1 x 15,000 L final drive oil
1 x 15,000 L premixed coolant
1 x 10,000 L waste coolant
Oil:
Additional fuel and oil storage will be developed onsite to allow for two 150,000 L vertical fuel storage tanks and two 25,000 L oil storage tanks. The storage area will be fenced and bunded. The bund and its associated pipe work, valves, and drainage will be designed to AS1940. The MIA area will also house several Drum Store Facilities.
2.18
ACCOMMODATION VILLAGE
The accommodation village both during construction and operation of the Project will be located on site approximately 1.7 km north of the CHPP. The construction village, servicing the mine and Rail and Services Corridor construction workforce, will be in commission for 24 months and will be then converted to accommodate the requirements of the operational village. The village will essentially be developed from the relocatable buildings. The mess and recreational facilities from the construction village will have been designed to ensure minimal modifications are required when village is converted from construction facilities to that of the operations village. The village will initially consist of approximately 300 beds, increasing during the Project life to accommodate workforce increases. An extra 60 beds will be available for occasions such as CHPP shut downs and other major operations throughout the mine life. The accommodation strategy allows for no room sharing and will reflect prevailing industry standards at the time off commissioning.
2.19
WORKSHOPS AND OFFICES
The Heavy Mining Equipment (HME) workshop building will be centrally located within the MIA, servicing heavy mining vehicles and equipment, and other general mine associated infrastructure that will be developed as part of the MIA. The HME will have four main sections; maintenance bays designed with a nominal size of 12 m x 20 m, tyre bays, local store areas, and office space with five open plan work stations. Office facilities and crib rooms will be located in the MIA area and along the Rail and Services Corridor
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during construction.
2.20
SEWERAGE TREATMENT
There are no existing facilities for the treatment of sewage in the vicinity of the Project. All sewage generated on site will be treated on site at a packaged STP located proximate to the accommodation village, where the bulk of the sewage will be generated. Sewage generated at the MIA and CHPP will be pumped to the STP by way of underground packaged sewage pump stations and buried rising mains. Treated waste water from the STP will be monitored monthly for contaminants in accordance with the Project’s EA, prior to being disposed of via low height sprays in a proposed irrigation area situated east of the accommodation village access road. The proposed area has been assessed against Environmental Guideline: Use of Effluent by Irrigation (Department of Environment and Conservation (NSW) 2003) in terms of soil suitability, groundwater vulnerability, surface water and flood potential. Soils in the proposed area of irrigation have been classified as the Cheshire Soil Management Unit and are consistent with descriptions provided in the Land Management Field Manual – Wandoan District (Gray and Macnish 1985) comprises of brown to black non-cracking clay with depths exceeding 600 mm. Soil chemistry indicates a soil which is mildly to moderately alkaline in pH. At the surface the soil has mostly low levels of major soil nutrients and organic carbon but has a high to very high cation exchange capacity (CEC) and is well structured and stable. Surface soils are non-saline and non-sodic before becoming sodic at 300 mm. The depth of useable soil resources extends to approximately 300 mm before sodicity and salinity potentially constrains usability. Landscapes of the Cheshire SMU consist of the upper to mid slopes of gently undulating plains which have been extensively cleared for agriculture. Flood modelling has confirmed that the area selected for effluent irrigation is unaffected by a 100 annual reoccurrence interval (ARI) event. The characteristics of this area comply with the recommendations of the Environmental Guideline: Use of Effluent by Irrigation (Department of Environment and Conservation (NSW) 2003). An effluent disposal system will be implemented to ensure that spray drift does not occur to any sensitive or commercial place. This will be achieved by the use of low pressure sprays with a greater number of spray nozzles for the required disposal area. In addition, the design of the system will take into account the need to ensure no runoff from the disposal area takes place. Environmental Guideline: Use of Effluent by Irrigation (Department of Environment and Conservation (NSW) 2003) was used to calculate the approximate area (ha) required for the allocation of treated effluent from the STP. The minimum irrigation area required based on organic loading was estimated using the following formula: A = CQ / (1,000 x Lc) Where: A = irrigation area (ha) C = concentration of BOD5 (mg/L) Q = average effluent flow rate (kL/month) Lc = critical loading rate of constituent (kg/ha/month)
Based on the assumption that the average loading rate of most soils is 1,500 kg/ha/month, the 2 minimum irrigation area calculated was to be 133 m .
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The STP has been designed to produce Class A effluent and will be developed in accordance with the Planning Guidelines for Water Supply and Sewerage (DEWS 2010) and the Queensland Water Recycling Guidelines (EPA 2005). The STP will be designed to encompass the following:
100% of the potable water (240 L per capita per day) will become waste water and returned to the STP for treatment;
Treatment plant capacity sufficient to allow for treatment of all flows over a 20 hour period;
Pump stations will be designed for peak wet weather inflows; and
Pumps and rising mains are to have capacity to deliver twice the peak incoming flow rates.
Two treatment plants will be required; a permanent base load plant and a temporary plant to accommodate the peak loads. Temporary facilities, such as portaloos, will be installed at major construction sites and replaced every 2 – 3 days for disposal at an authorised treatment plant.
2.21
RUBBISH DISPOSAL
General mine waste (other waste rock and washery waste), that cannot be recycled or reused, will be removed from site by contractors or disposed of in an on-site landfill. If required, the rubbish disposal site (landfill) will be located on MLA 50271. It is assumed that each person will create 1.5 t of general waste for disposal at the rubbish disposal site per annum. With an estimated maximum of 150 personnel on site at any one time during peak operation the amount of general waste created will be approximately 225 tpa. This equates to 3 approximately 1,125 m of landfill volume per year with an equivalent surface area of 24 m x 24 m (assuming 2 m depth). The rubbish disposal site will be selected in accordance with the EHP EcoAccess Guideline Landfill Siting, Design, Operation and Rehabilitation. Odour at the rubbish disposal site will be managed by regularly covering the waste with soil (at least fortnightly during peak operations). The disposal site will be progressively developed in compartmentalised cells to minimise the active face and reduce potential for windblown rubbish. The disposal site will be managed such that stormwater runoff is directed away from disposal cells and any direct rainfall is captured and evaporated, rather than being released to the environment. The rubbish disposal site will be monitored through regular visual assessments to ensure long term environmental performance.
2.21.1
Construction Material
During the construction period, approximately 200 truckloads per week of plant and bulk material will be imported to the Project site from within the local area and the major centres of Toowoomba, Brisbane and Gladstone. A large majority of these loads (98%) will be raw materials including clays, gravel, sand, coarse rock and aggregate that will be required during construction.
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Both Boral Limited (Boral) and Ostwald Bros. are exploring development opportunities for quarries within the region to meet the construction demands of the Elimatta Project and other projects in the area. Taroom Coal intends to source raw construction material from Boral – Warrians Quarry located approximately 100 km southwest of Project site, off the Roma-Taroom Road at Euthulla and Ostwald Bros – Knob Hill Quarry located approximately 120 km northeast of Project site, off Knudsens Road at Bungaban.
2.22
ENVIRONMENTALLY RELEVANT ACTIVITIES
Table 5.33 describes the activities proposed to be conducted on the Project which would otherwise be ERAs as per Schedule 2 of the EP Regulation if the Project were not considered as a resource activity requiring an environmental authority. However, mining projects are covered separately under Schedule 2A of the EP Regulation and the Aggregate Environmental Score for the Project is shown in Table 5.33. As the proposed Project is a Level 1 Mining Activity, the relevant Annual Fee payable for the Project is $29,248.00 reflected by Table 5.34. Table 5.33
Activities associated with the Project that would otherwise be considered ERAs
Environmentally Relevant Activity
Threshold
3
Chemical Storage
Storing 200m or more of chemicals that are liquids, other than chemicals mentioned in items 1 to 3 under Schedule 2, section 8, subsection (1)(d)
Fuel burning
Fuel burning operation using equipment capable of burning at least 500 kg/hr
Extractive and Screening Activities
Extracting more than 1,000,000 tpa of material; Screening more than 1,000,000 tpa of material
Crushing, milling, grinding or screening
More than 5,000t of materials in a year
Mineral Processing
Processing, in a year, the following quantities of mineral products, other than coke - more than 100,000t
Bulk material handling
Loading or unloading 100t or more of minerals in a day or stockpiling 50,000t or more of minerals
Regulated Waste Storage
Receiving and storing regulated waste
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Environmentally Relevant Activity
Threshold
Waste Disposal
Waste disposal facility (regulated and general waste) 100-1500 Equivalent Persons with effluent discharged from works to an infiltration trench or through an irrigation scheme
Table 5.34
2.23
Mining Activities and Annual Fees Associated with the Project Activity
Aggregate Environmental Score
13. Mining Black Coal
128
REHABILITATION AND DECOMISSIONING
Rehabilitation strategies and methods for the Elimatta Project were designed to meet the requirements of Section 203 of the EP Act and have been structured in accordance with the Guideline 18: Rehabilitation Requirements for Mining Projects (DERM 2011) and the Technical Guidelines for the Environmental Management of Exploration and Mining in Queensland (1995). In order to ensure best practice in all facets of rehabilitation, the Leading Practice Sustainable Development for the Mining Industry series of booklets has been used in the development of site specific rehabilitation methods, in particular:
Leading Practice Sustainable Development Program for the Mining Industry – Mine Closure and Completion (Commonwealth of Australia 2006a);
Leading Practice Sustainable Development Program for the Mining Industry – Mine Rehabilitation (Commonwealth of Australia 2006b); and
Leading Practice Sustainable Development Program for the Mining Industry – Tailings Management (Commonwealth of Australia 2007).
Other guidelines that were consulted in the development of the rehabilitation strategies included:
Guideline 16: Final and Progressive Rehabilitation and Audit Statements for Level 1 Mining Lease (DERM 2011); and
Technical Guidelines for Open Pit Rehabilitation (DERM 1995).
2.23.1
Rehabilitation Hierarchy
The rehabilitation hierarchy for the Elimatta Project was developed in accordance with Guideline 18: Rehabilitation Requirements for Mining Projects (DERM 2011). The hierarchy, in order of decreasing capacity to prevent or minimise environmental harm is as follows:
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1. Avoid disturbance that will require rehabilitation 2. Reinstate a “natural” ecosystem as similar as possible to the original 3. Develop an alternative outcome with a higher economic value than the previous land use 4. Reinstate previous land use 5. Develop a lower value land use 6. Leave the site in an unusable condition or with a potential to generate future pollution or adversely affect environmental values The hierarchy allows for lower values to be acceptable when they will be appropriate to the stakeholders or when higher values are impractical. However, leaving the site in an unusable condition or with the potential to cause further environmental harm is not considered acceptable and has not been proposed for the Elimatta Project. Where disturbance cannot be practically avoided (hierarchy item 1), the overarching rehabilitation principal of the Elimatta Project is to remediate the disturbed area to a land use consistent with low intensity cattle grazing and reinstate riparian and temperate habitats. This reflects the natural ecosystems and land use of the site pre-mining, as per hierarchy item 2 and 4. It is expected that some disturbance areas, such as final voids, may achieve a reduced land value upon rehabilitation in accordance with hierarchy item 5. During the operational life of the mine consultation with stakeholders including local communities and government authorities may indicate a preference for an alternative post mining land use of higher economic value. If such a situation arises then NEC will investigate the options in consultation with these stakeholders. It is assumed that the Rail and Services Corridor infrastructure will be retained post decommissioning of the Elimatta Project as it will continue offer a significant benefit to resource developers, other land users and the general public. As result, Rail and Services Corridor infrastructure is not specifically addressed in this rehabilitation section.
2.23.2
Rehabilitation Goals
The rehabilitation goals have been developed in accordance with Guideline 18: Rehabilitation Requirements for Mining Projects (DERM 2011). The goals of the rehabilitation are to return the Elimatta Project site to a state that is:
Safe to humans and wildlife;
Non-polluting;
Stable; and
Able to sustain the agreed post mining land use.
Adoption of the rehabilitation goals aims to achieve long term maintenance of essential ecological processes for the Elimatta site, post mining.
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2.23.3
Mine Domain Objectives
In order to achieve the described rehabilitation goals for the site, specific rehabilitation objectives have been developed for each individual mine domain. A mine domain is made up of land management units within a mine site that have similar characteristics. Six domains have been determined for the Project. The domain name and the mine areas included are detailed in Table 5.35. Table 5.35 Elimatta Mine Domains Domain:
Mine areas included:
Final Voids
Final Voids; and, In-Pit TSF (TDP)
Exploration Areas
Exploration Areas
Dams
Environmental Dams Raw Water Dams Sediment Dams
Diversions
Horse Creek Diversion
Infrastructure
Buildings, including foundations; Roads; Chemical/fuel storages; and CHPP.
Waste Disposal
In-pit dump; Out-of-pit dump; and, Surface TSFs (TDN and TDNA)
Development of rehabilitation objectives, specific for the land disturbance type, is a requirement of Section 203 of the EP Act. Table 5.36 below describes the Elimatta Project rehabilitation objectives for each mine domain.
2.23.4
Rehabilitation Indicators
Rehabilitation indicators have been developed for the Elimatta Project to provide measures of progress towards the mine domain rehabilitation objectives. In the case of the Project, some indicators have been deemed relevant to a number of domains whilst other indicators have only a local significance to one mine domain. Rehabilitation indicators for the Elimatta project are provided in Table 5.36.
2.23.5
Completion Criteria
Completion criteria have been proposed for the Elimatta Project to provide standards for determining successful rehabilitation for each domain. Completion criteria take the form of a set of measurable benchmarks against which the rehabilitation can be compared to determine if the chosen objectives are being met. Evidence of the completion criteria having been addressed will be collected as part of the
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rehabilitation monitoring program (see Section 2.23.12) to assist in determining rehabilitation success. The domains within the Project site are deemed to be successfully rehabilitated when completion criteria for each rehabilitation goal and objective have been met over a long term period. Table 5.36 outlines the completion criteria, indicators, objectives and rehabilitation goals proposed for the Elimatta Project.
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Table 5.36 Completion Criteria, Indicators, Objectives and Rehabilitation Goals Rehabilitation Goal
Rehabilitation Objective
Rehabilitation Indicator
Completion Criteria
Domain – Final Void
All remaining voids are safe for humans and animals
Safety barriers and signage assessed against requirements of the Coal Mining Safety and Health Act 1999
Evidence in rehabilitation report that all safety precautions have been taken in accordance with the relevant legislation
Safety assessment of final landform by an appropriately qualified person
Evidence in rehabilitation report that safety precautions have been implemented in accordance with relevant legislation
Domain – Exploration Areas
Safe Site
Exploration sites are safe for humans and animals
Safety assessment of rehabilitated site by an appropriately qualified person
Evidence in rehabilitation report that ground is structurally safe
Domain – Infrastructure
All infrastructure sites are safe for humans
Safety assessments of final landform by an appropriately qualified person
Certification in rehabilitation report that final landform is structurally sound and safe
Domain – Dams
Dam sites are safe for humans and animals
Elimatta Project
Safety assessment of final landform by an appropriately qualified person
Certification in rehabilitation report that ground is structurally sound and safe to people and animals
Safety barriers and signage assessed against requirements of the Coal Mining Safety and Health Act 1999
Evidence in rehabilitation report that all safety precautions have been implemented in accordance with the relevant legislation
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Rehabilitation Goal
Rehabilitation Objective
Rehabilitation Indicator
Completion Criteria
Domain – Diversions Safety barriers and signage assessed against requirements of the Coal Mining Safety and Health Act 1999
Evidence in rehabilitation report that all safety precautions have been taken in accordance with the relevant legislation
Safety assessment of final landform by an appropriately qualified person
Evidence in rehabilitation report that safety precautions have been implemented in accordance with relevant legislation
Diversions are safe for humans and animals
Domain – Waste Disposal
Waste disposal sites safe for humans and animals
Safety assessment of final landform by an appropriately qualified person
Certification in rehabilitation report that landform is structurally sound and safe
Exposure to and availability of heavy metals or any other toxic materials in the environment
Evidence in the rehabilitation report that post closure monitoring (air, soil, water, stream sediments) shows the final landform is compliant with limits in the relevant Environmental Protection Policies or other agreed limits.
Domain – Final Void
Non - polluting
Elimatta Project
Hazardous and contaminated material adequately managed
Safety assessment of final landform by an appropriately qualified person
Certification in rehabilitation report that final landform is structurally sound and safe
Rehabilitation monitoring plan in place to monitor void water quality, downstream surface water, groundwater and stream sediments
Evidence in the rehabilitation report that post closure monitoring (void water, surface water, groundwater, stream sediments) shows the final landform is compliant with limits in the relevant Environmental Protection Policies or other agreed limits
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Rehabilitation Goal
Rehabilitation Objective
Rehabilitation Indicator
Completion Criteria
Domain – Exploration Areas
Hazardous material adequately managed
Site inspection by an appropriately qualified person
Evidence in rehabilitation report that all exploration sites have been cleaned up and rehabilitated to an acceptable standard
Domain – Infrastructure Hazardous and contaminated material adequately managed Runoff and seepage will be of good quality water that is unlikely to affect known environmental values
Contaminated Land Assessment undertaken
Evidence of remediated landform in a contaminated land assessment report.
Rehabilitation monitoring plan in place to monitor downstream surface/ground water
Evidence in rehabilitation report that monitoring data is meeting specified contaminant and trigger levels that ensure environmental values are not being compromised
Domain – Dams
Dams to remain on closure will not contribute contaminants to the environment
Rehabilitation monitoring plan in place to monitor water in the dam and downstream surface/ground water
Evidence in the rehabilitation report that post closure monitoring (water quality) is compliant with limits in the relevant Environmental Protection Policies or other agreed limits.
Rehabilitated dams will not contribute contaminants to the environment
Rehabilitation monitoring plan in place to monitor downstream surface/ground water
Evidence in the rehabilitation report that monitoring data meets specified contaminant and trigger levels
Hazardous and contaminated material adequately managed
Contaminated Land Assessment undertaken
Evidence of remediated landform in a contaminated land assessment report.
Domain – Diversions
Discharge will be of good quality water that is unlikely to affect known environmental values
Rehabilitation monitoring plan in place to monitor downstream surface water
Evidence in rehabilitation report that monitoring data is meeting specified contaminant and trigger levels that ensure environmental values are not being compromised
Domain – Waste Disposal
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Rehabilitation Goal
Rehabilitation Objective
Rehabilitation Indicator
Completion Criteria
Engineers assessment of cover or final landform design
Engineers certification in rehabilitation report that the waste disposal site has been securely covered to prevent any release or seepage of hazardous or contaminated material
Rehabilitation monitoring plan in place to monitor downstream surface/ground water
Evidence in the rehabilitation report that monitoring data demonstrates the cover is functioning in preventing any release or seepage of hazardous or contaminated material
Hazardous and contaminated material adequately managed
Domain –Final Voids
Minimal probability of wall failure or rock falls that will cause significant environmental harm
Geotechnical studies of final voids
Evidence in rehabilitation report of geotechnical studies to determine whether final landform is stable
Risk assessment of final landform
Evidence in rehabilitation report that appropriate risk assessment and control measures have been undertaken
Domain –Exploration Areas Stable Landform
Landform achieves appropriate erosion rates
Vegetation cover to minimise erosion
Engineers assessment of design and construction of structures to control water and sediment flow
Evidence in rehabilitation report that required sediment control structures are in place and functioning correctly
Vegetation assessment
Evidence in the rehabilitation report that the revegetation meets the limits set by the analogue sites
Domain – Infrastructure
Landform achieves appropriate erosion rates
Elimatta Project
Engineers assessment of design and construction of structures to control water flow
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Engineer certification in rehabilitation report that infrastructure sites (both remaining and decommissioned) have the required structures to control water flow and runoff
2014
Rehabilitation Goal
Rehabilitation Objective
Vegetation cover to minimise erosion
Rehabilitation Indicator
Completion Criteria
Vegetation assessment
Evidence in the rehabilitation report that the revegetation meets the limits set by the analogue sites
Domain – Dams
Minimal probability of subsidence that will cause significant environmental harm
Vegetation cover to minimise erosion
Geotechnical studies of final landforms
Evidence in rehabilitation report of geotechnical studies to determine whether final landform is stable
Risk assessment of final landform
Evidence in rehabilitation report that appropriate risk assessment and control measures have been undertaken
Vegetation assessment
Evidence in the rehabilitation report that the revegetation meets the limits set by the analogue sites
Domain – Diversions
Minimal probability of subsidence that will cause significant environmental harm
Vegetation cover to minimise erosion
Geotechnical studies of final landforms
Evidence in rehabilitation report of geotechnical studies to determine whether final landform is stable
Risk assessment of final landform
Evidence in rehabilitation report that appropriate risk assessment and control measures have been undertaken
Vegetation assessment
Evidence in the rehabilitation report that the revegetation meets the limits set by the analogue sites
Domain – Waste Disposal Minimal probability of subsidence or rock falls that will cause significant environmental harm
Elimatta Project
Geotechnical studies of final landforms
5-95
Evidence in rehabilitation report of geotechnical studies to determine whether final landform is stable
2014
Rehabilitation Goal
Rehabilitation Objective
Vegetation cover to minimise erosion
Rehabilitation Indicator
Completion Criteria
Risk assessment of final landform
Evidence in rehabilitation report that appropriate risk assessment and control measures have been undertaken
Vegetation assessment
Evidence in the rehabilitation report that the vegetation type and density are of species suited to the slope, aspect, climate and other factors, and that the measured erosion rates meets the limits set by analogue sites
Domain –Final Voids
Establish safe and stable waterbody with low risk of environmental harm
Rehabilitation monitoring plan in place to monitor void water quality
Evidence in rehabilitation report that monitoring data is meeting livestock contaminant limits and that no risk to wildlife exists
Domain –Exploration Areas
Soil properties that support desired land use
Soil monitoring program in place to ensure remaining soil is able to support post-mining land use
Sustains agreed land use
Self-sustaining natural vegetation and habitat established
Vegetation assessment
Evidence in rehabilitation report that all soil chemical, physical, and biological properties of are within acceptable limits that ensure soil is able to support postmining land use Certification within the rehabilitation report that key species are present, suitable diversity has been achieved and cover/density is adequate Certification within the rehabilitation report that the Pest and Weed Management Plan has been successful
Domain – Infrastructure Soil properties that support desired land use
Elimatta Project
Soil monitoring program in place to ensure remaining soil is able to support
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Evidence in rehabilitation report that all soil chemical, physical, and
2014
Rehabilitation Goal
Rehabilitation Objective
Self-sustaining natural vegetation and habitat established
Rehabilitation Indicator
Completion Criteria
post-mining land use
biological properties of are within acceptable limits that ensure soil is able to support postmining land use
Vegetation assessment
Certification within the rehabilitation report that key species are present, suitable diversity has been achieved and cover/density is adequate Certification within the rehabilitation report that the Pest and Weed Management Plan has been successful
Domain – Dams For dams which are to remain on decommissioning, establish safe and stable water body with a low risk of environmental harm
For dams to be rehabilitated, soil properties that support desired land use
For dams to be rehabilitated, selfsustaining natural vegetation and habitat established
Water quality established by monitoring or modelling validated by monitoring
Evidence in the rehabilitation report that the dams meets water quality guidelines
Structural report on integrity of structure
Engineers certificate of structure
Soil monitoring program in place to ensure remaining soil is able to support post-mining land use
Evidence in rehabilitation report that all soil chemical, physical, and biological properties of are within acceptable limits that ensure soil is able to support postmining land use
Vegetation assessment
Certification within the rehabilitation report that key species are present Certification within the rehabilitation report that species diversity has been achieved Certification within the rehabilitation report that the Pest and Weed Management Plan has been successful
Domain – Diversions Establish safe and stable waterway with a low risk
Elimatta Project
Water quality established by monitoring or modelling validated by
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Evidence in the rehabilitation report that the dams meets water
2014
Rehabilitation Goal
Rehabilitation Objective
Rehabilitation Indicator
Completion Criteria
of environmental harm
monitoring
quality guidelines
Structural report on integrity of structure
Engineers certificate of structure
Self-sustaining natural vegetation and habitat established
Vegetation assessment
Certification within the rehabilitation report that key species are present, suitable diversity has been achieved and cover/density is adequate Certification within the rehabilitation report that the Pest and Weed Management Plan has been successful
Domain – Waste Disposal
Soil properties that support desired land use
Self-sustaining natural vegetation and habitat established
2.23.6
Soil monitoring program in place to ensure remaining soil is able to support post-mining land use
Evidence in rehabilitation report that all soil chemical, physical, and biological properties of are within acceptable limits that ensure soil is able to support postmining land use
Vegetation assessment
Certification within the rehabilitation report that key species are present, suitable diversity has been achieved and cover/density is adequate Certification within the rehabilitation report that the Pest and Weed Management Plan has been successful
Progressive Rehabilitation Strategy
The Elimatta Project is committed to undertaking progressive rehabilitation throughout the life of mine. The progressive rehabilitation strategy will target areas as soon as they become available for rehabilitation. This approach aims to minimise the total disturbance existing at any point in time during the life of the mine. Benefits of this approach include:
Minimising erosion on the site;
Minimising dust emission from the site;
Reducing the time for which topsoil remains stockpiled leading to an increased regeneration
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from the seed bank;
Minimising the ecological impacts of clearing, such as reduced habitat for fauna; and
Minimising the social / visual impacts of the Project.
2.23.7
Post Mining Land Use
In accordance the rehabilitation hierarchy, rehabilitation of disturbed areas will primarily aim to reinstate a land condition as similar as possible to the pre-mining landscape. For a majority of the Project area, the proposed post-mining land use and condition will be consistent with the current primary land use of low intensity cattle grazing. Riparian habitats will be established along the length of the Horse Creek Diversion consistent with the rehabilitation outcomes proposed for the diversion. Confirmation of the success of rehabilitated area will be accomplished through the establishment of analogue and rehabilitation monitoring sites whereby measurable indicators will be assessed periodically to determine appropriate targets representative of the pre-mining land use. In accordance with the rehabilitation hierarchy and goals for the Elimatta Project, described in Table 5.36, the majority of the mine domains will be rehabilitated with the aim of recreating a land use consistent with low intensity cattle grazing. The diversion of Horse Creek will be rehabilitated to reinstate riparian and temperate habitats consistent with the pre-mining land use of this area.
2.23.8
Soil Management
The Soil and Land Suitability Assessments for the Elimatta Project Mining Areas describe six Soil Management Units within the Elimatta Project area. These were classified as the Downfall, Kinnoul, Cheshire, Rolleston, Juandah and Horse Creek Alluvium Soil Management Units. Additional soil management units have been described over the Rail and Services Corridor. As described in Section 2.23.1, the multi-user infrastructure proposed for development within the Rail and Services Corridor is expected to remain as a functioning asset to local and regional users. As such, these additional soil units have not been included in this section. The Downfall, Kinnoul, Cheshire, Rolleston and Juandah units possess sodic subsoils with increasing levels of exchangeable sodium within the upper 900 mm of the profile. Salinity also increases with depth within these profiles, to levels considered moderate to highly saline by 900-1000 mm. An exception to this is the Horse Creek Alluvium SMU, with no signs of sodicity or salinity present within the profile. With the exception of the Horse Creek Alluvium SMU, the soils of the project site are all considered to have restrictions for stripping, stockpiling and rehabilitation. All soils present on the Project site are considered moderately deficient of major soil nutrients. As such, long term (in excess of 6 months) topsoil stockpiles will be ripped and seeded to maintain soil biota and a viable seed bank. Useable soil resources are mainly confined to the surficial horizons and locally in the upper part of the subsurface horizons which contain seed-stock, micro-organisms and nutrients necessary for plant growth. The following list presents the soil management units in terms of the quality of their topsoil resource (from most to least suitable) and outlines their recommended stripping depths:
Horse Creek Alluvium Soil Management Unit – 1000 millimetres;
Cheshire Soil Management Unit – 300 millimetres;
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Rolleston Soil Management Unit – 200 millimetres;
Downfall Soil Management Unit – 200 millimetres;
Kinnoul Soil Management Unit – 100 millimetres; and
Juandah Soil Management Unit – 0 millimetres.
The topsoil stripping and stockpiling strategy for the Elimatta Project will target the above soil depths for each Soil Management Unit on the site. In addition, the strategy will aim to:
Minimise the time soil is stockpiled prior to it being used in rehabilitation;
Minimise the transport distance between topsoil stripping and stockpiling;
Stockpile topsoil up to a maximum of 2 m in height away from drainage areas, roads, machinery, transport corridors, and stock grazing areas; and
Rip and seed with a quick establishment pasture, to limit erosion, and maintain a viable seed bank if the period of stockpiling is greater than one growing season or six months.
2.23.9
Final Rehabilitated Landform of the Elimatta Project
Figure 5.28 and Figure 5.29 below provides a layout of the Elimatta Project final landform. Details of rehabilitation strategies for each mine domain are discussed in the following sections.
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Figure 5.28
Elimatta Project
Elimatta Project Final Landform (MLA 50270, MLA 50271)
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Figure 5.29
Elimatta Project
Elimatta Project Final Landform (MLA 50254)
5-102
2014
2.23.10 Rehabilitation Methodology The rehabilitation methodologies described below have been designed to meet the rehabilitation goals, indicators and objectives described in Table 5.36. The methodologies will be subject to change during mine life with:
New information learnt from trials and experience; and
New technology and research becoming available.
2.23.10.1 Contouring The preparation of disturbed areas prior to the establishment of vegetation will involve surface contouring to minimise erosion and maximise water retention. Recreated landforms will be contoured to resemble the original local topography with spoil dumps shaped to resembles low hills. 2.23.10.2 Ripping Following contouring, ripping of the surface will be carried out. The design criteria for ripping operations are detailed in Table 5.37. The spacing between rip lines is determined by the slope of the land, which acts to reduce soil erosion and increase plant establishment rates. Where soils are particularly compacted, a more suitable ripping depth of 300 mm or more would be employed. Table 5.37 Design of Ripping Operations for Post-disturbance Surface Preparation
Slope
Minimum Ripping Depth
Tyne Spacing
>10%
200 mm