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TRANSCRIPT
JULY 2010
WELD RANGE IRON ORE PROJECT
CONCEPTUAL CLOSURE PLAN
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Document Status
Approved for Issue Rev. Author Reviewer/s Date
Name Distributed To Date
1 T. Souster W. Ennor March 2009
2 T. Souster W. Ennor Dec 2009
3 R Gabbitus M Wood May 2010
4 R Gabbitus M Wood July 2010
ecologia Environment (2010). Reproduction of this report in whole or in part by electronic, mechanical or chemical means including photocopying, recording or by any information storage and retrieval system, in any language, is strictly prohibited without the express approval of Sinosteel Midwest Corporation Pty Ltd and/or ecologia Environment.
Restrictions on Use
This report has been prepared specifically for Sinosteel Midwest Corporation Pty Ltd. Neither the report nor its contents may be referred to or quoted in any statement, study, report, application, prospectus, loan, or other agreement document, without the express approval of Sinosteel Midwest Corporation Pty Ltd and/or ecologia Environment.
ecologia Environment
1025 Wellington Street
WEST PERTH WA 6005
Phone: 08 9322 1944
Fax: 08 9322 1599
Email: [email protected]
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TABLE OF CONTENTS
CHECKLIST .....................................................................................................................................VII 1 INTRODUCTION ................................................................................................................ 1 1.1 PURPOSE ...................................................................................................................................1 1.2 PROJECT DESCRIPTION..............................................................................................................1 1.3 TENEMENT INFORMATION .......................................................................................................7 1.4 CONTACT INFORMATION..........................................................................................................9 2 CLOSURE OBJECTIVES...................................................................................................... 11 2.1 END LAND USE ........................................................................................................................12 3 BASELINE ENVIRONMENTAL DATA.................................................................................. 13 3.1 CLIMATE ..................................................................................................................................13 3.2 CLIMATE AND METEOROLOGY................................................................................................14 3.3 GEOMORPHOLOGY .................................................................................................................15 3.4 LAND SYSTEMS AND SOILS......................................................................................................15 3.5 GEOLOGY.................................................................................................................................16 3.6 GROUNDWATER......................................................................................................................17 3.7 BIOLOGICAL.............................................................................................................................19 4 LEGAL OBLIGATIONS ....................................................................................................... 21 4.1 GUIDELINES AND CODES OF PRACTICE ...................................................................................22 5 POLICY............................................................................................................................ 25 6 STAKEHOLDER CONSULTATION....................................................................................... 27 7 PLANNING ...................................................................................................................... 29 7.1 RISK ASSESSMENT ...................................................................................................................29 7.2 PROJECT CONDITION REPORTS...............................................................................................30 7.3 COMPLETION CRITERIA AND PERFORMANCE INDICATORS....................................................30 7.4 TARGETED RESEARCH .............................................................................................................34 8 FINANCIAL PROVISION.................................................................................................... 35 8.1 COST ESTIMATE.......................................................................................................................35 8.2 CLOSURE SCHEDULE................................................................................................................37 8.3 ACCOUNTING STANDARDS .....................................................................................................37 8.4 ADEQUATE SECURITIES ...........................................................................................................37 8.5 REVIEW....................................................................................................................................39 9 GENERAL REHABILITATION AND CLOSURE STRATEGIES ................................................... 41 9.1 WASTE LANDFORM.................................................................................................................41
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9.2 CONTAMINATED SITES............................................................................................................43 9.3 SURFACE WATER.....................................................................................................................45 9.4 GROUNDWATER......................................................................................................................49 9.5 DECOMMISSIONING................................................................................................................50 9.6 VISUAL AMENITY AND HERITAGE ...........................................................................................52 9.7 REHABILITATION OF NATIVE VEGETATION AND TOPSOIL ......................................................53 10 SPECIFIC CLOSURE STRATEGIES ....................................................................................... 57 10.1 BEEBYN AND MADOONGA PIT CLOSURE ................................................................................57 10.2 WASTE ROCK DUMPS..............................................................................................................60 10.3 OVERBURDEN STOCKPILES......................................................................................................63 10.4 BORROW PITS AND HAUL ROADS ...........................................................................................66 10.5 DEWATERING BOREFIELDS AND PIPELINES ............................................................................67 10.6 POWER GENERATING AND SUPPLY INFRASTRUCTURE...........................................................67 10.7 ACCOMMODATION VILLAGE AND AMENITIES........................................................................68 11 MONITORING AND MAINTENANCE................................................................................. 69 11.1 MONITORING, REPORTING AND RECORD KEEPING................................................................69 11.2 MAINTENANCE........................................................................................................................70 12 CONTINGENCY PLANNING............................................................................................... 71 12.1 WALKAWAY.............................................................................................................................71 12.2 TEMPORARY CLOSURE ............................................................................................................73 12.3 RELINQUISHMENT...................................................................................................................73 13 REVIEW AND REVISION................................................................................................... 75 14 REFERENCES.................................................................................................................... 77
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TABLES
Table 1.1 – Key Aspects of the Weld Range Iron Ore Project ..................................................................3 Table 1.2– Weld Range Tenements held by or applied for by SMC .........................................................8 Table 1.3 – Prospecting Licenses Applied for in Substitution for TR 70/3902H.......................................9 Table 4.1 – Legislation Applicaple to the Project. ..................................................................................21 Table 4.2 – Guidelines and Codes of Practice. .......................................................................................22 Table 6.1 – Stakeholder Consultation. ...................................................................................................27 Table 7.1 – Closure Criteria ....................................................................................................................32 Table 8.1 – Closure Cost Estimate ..........................................................................................................36 Table 8.2 Mine Closure Schedule ...........................................................................................................37 Table 8.3 – Unconditional Performance Bonds for SMC Tenements .....................................................38 Table 10.1 – Monitoring for sailinty, pH and leaching of contaminates for pit lakes ............................58 Table 11.1 – Timing of Closure Monitoring ............................................................................................69
FIGURES
Figure 1.1 – Project location and infrastructure layout. ..........................................................................5
Figure 3.1 – Western Murchison Subregions and SurroundsL MUR1 – Eastern Murchison, MUR2 ‐ Western Murchison (Based on IBRA Version 6.1 Thackway and Cresswell 1995). ...........13
Figure 3.2 – Summary of Climatic Data for Meekatharra Airport (BOM, 2009).....................................14
Figure 9.1 – Madoonga Mine Pit and Waste Dump Drainage................................................................47
Figure 10.1 – Indicative Cross Section of Surfacewater Diversion Trench and Abandument Bund.......59
Figure 10.2 – Cross Section of the Proposed Waste Dump Design ........................................................62
Figure 10.3 – PAF Waste Rock Surrounded by NAF Waste Rock............................................................63
Figure 11.1 – Maintenance Actions........................................................................................................70
Figure 12.1 – Sudden Closure Strategy ..................................................................................................72
Figure 12.1 – Temporay Closure Strategy ..............................................................................................74
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CHECKLIST
Required Information Y/N NA
Page No Comments
1 Has the closure plan been endorsed with the mine manager signature and company seal and an endorsement certificate attached?
Y xi
2 Has a closure plan checklist been completed, signed, dated and attached to the closure plan?
Y Viii to x
3 Has an introduction been added, containing a brief summary of the operation?
Y xii to xiii
Mine Information
4 Have all relevant personnel and their up to date contact information been listed in the mine information section?
Y 9
5 Has the location of the mine site been described on a regional and local scale?
Y 1
6 Has appropriately scaled regional and local maps been attached? Y 5
7 Has an appropriately scaled map showing all tenement boundaries and the associated mine infrastructure and disturbed areas been attached?
Y 5
8 Are aerial maps attached to show terrain and landscape in relation to tenement boundaries and mine disturbance?
Y 5
9 Has information on any historic disturbance and/or environmental liabilities been included?
NA NA
Updated Information
10 If this is an annual closure plan update, is there an updated information section included?
Y ii
Conditions Compliance
11 Have all environmental conditions relating to closure objectives been listed?
NA
12 Has a description of required works been included alongside each condition listed?
NA
Environmental & Rehabilitation Commitments
13 Has a list of all environmental & rehabilitation mining approval commitments been included?
Y 41 to 57
14 Has the environmental & rehab mining approval commitments been referenced with the relevant approval document?
Y 41 to 57
15 Have all disturbance types (domains) been given their own headings within the closure plan?
Y 41 to 57
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16 Have multiple waste landforms (WD & TSF) been identified separately within the closure plan?
N
Closure Criteria & Standards
17 Has closure objectives, criteria, standards and commitments been discussed under each disturbance type (Domain)?
Y 30 and 32 to 33
Monitoring & Research Trials
20 Has information on monitoring & research programs been included? Y 34 and 69
Decommissioning Plan
21 If this is a final closure plan, has a detailed decommissioning plan been attached?
N
Stakeholders
22 Has a list of all identified stakeholders been included? Y 27
23 Have all stakeholder contact details been included? NA
24 Have all stakeholder interests in the closure process been discussed? Y 27
Risk Analysis
25 Has the operations risk analysis process been explained? Y 29 to 30
26 Has a list of all identified risks to closure objectives been added, in order of highest risk to lowest risk?
NA
27 Has risk mitigation plans/processes been detailed? NA
28 Has all risk mitigation options been detailed including rationale for implementing selected plans/processes
NA
Rehabilitation Resources
29 Has the quantity, quality and storage requirements for closure rehab resources been discussed?
Y 53
30 Have contingency plans been explained for potential deficiencies in the quantity and quality of rehab resources at closure?
NA
Waste Characterisation
31 Has a waste characterisation program been carried out across the operation?
Y
41 to 43 and 60 to 63
32 Has all potentially hazardous materials to rehabilitation been identified?
Y
41 to 43 and 60 to 63
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33 Have risk mitigation plans/processes been detailed for each hazardous material identified.
NA
Education Program
34 Has the operations mine closure education program been included? NA
Financial Provisioning
35 Has a calculations table been included to show projected costs of closure?
Y 36
36 Has a separate calculations table been included to show projected cost of closure within 12 months?
Y 37
Unexpected Closure
37 Has the operations commitments to rehabilitation upon unexpected closure been included?
Y 71 and 72
38 Has a contingency plan for environmental commitments upon unexpected closure been included?
Y 72
Post- Mining Land Use
39 Has the proposed post‐mining land use for the operation been discussed?
Y 12
40 Has approval for any proposed change to rehab commitments been included?
NA
Heritage
41 Has any heritage issue that may affect the closure objectives been identified?
Y 52
42 Has risk mitigation plans/processes for potential heritage issues been included?
Y 53
Care & Maintenance (temporary closure)
43 Has the operations commitments to rehabilitation in the case of temporary closure (care & maintenance) been included?
Y 71 and 73 to 74
44 Has the closure plan been addressed to the relevant Environmental Inspector and DMP office?
NA
Submissions
45 Have the correct amount of hard copies been included in the submission?
NA
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I hereby certify that to the above checklist accurately reflects the information contained within this mine closure plan.
Name:
Position:
Company:
Signed: Date:
ENDORSEMENT CERTIFICATE
I hereby certify that all closure objectives, standards and commitments made in this mine closure plan will be completed within the timeframes, and to the standards stated. I also certify that all information contained within this mine closure plan is correct and accurate at time of submission.
Name:
Position:
Company:
Sign: Date:
Company Seal:
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EXECUTIVE SUMMARY
Sinosteel Midwest Corporation Ltd (SMC) is an incorporated entity, set up to conduct mineral exploration, engineering, environmental and economic studies into the feasibility to mine at Weld Range. Weld Range is located 85 km southwest of Meekatharra and 60 km northwest of Cue in Western Australia.
The Weld Range Iron Ore Project (the Project) is a direct shipping iron ore project with high grade outcrops over a 60 km strike length. Two ore bodies (Beebyn and Madoonga) have been identified at Weld Range, both of which are narrow and long with strike lengths in the order of 3 km. SMC is targeting to export 15 million tonnes per annum of iron ore over a 15 year period. The Public Environmental Review (PER) document addresses the first 11 years of planned operations.
This Conceptual Closure Plan has been developed to provide more certainty to the long term elements of the mine planning cycle and to provide greater flexibility around the shorter term mine planning. This Conceptual Closure Plan forms part of the documentation that will be submitted for environmental approval with the Weld Range Iron Ore Project PER (Assessment number 1714).
Site closure, both at the end of the mine life or running concurrently with mining activities, is a critical component of mine management, and ensures there are no ongoing adverse environmental impacts. By developing a closure plan as part of the planning stages of the Project, SMC is demonstrating that areas impacted by the Project will be left in a condition acceptable to regulators, post‐mining land users and the community.
Planning for mine closure seeks to address the social, environmental, financial and safety aspects of mine closure. The aim is to prevent or minimise long‐term environmental impacts and to create a self‐sustaining natural ecosystem or alternate land use based on an agreed set of objectives (ANZMEC, 2000). In undertaking mine closure activities at areas impacted by the Project, SMC will fulfil the following objectives:
• Ensure, as far as practicable, that rehabilitation achieves a long term, safe, stable and functioning landform which is consistent with the surrounding landscape and pre‐existing environmental values.
• Conduct effective consultation to enable stakeholders, including regulatory agencies, non‐government organisations and other interested parties, to have their interests considered during the mine closure process.
• Ensure that commitments made to stakeholders and regulators are fulfilled.
• Ensure that public safety is protected.
• Minimise negative impacts to the surrounding environment.
• Ensure legislative requirements are met.
• Re‐establish landforms and vegetation communities to meet the agreed post‐mining land use requirements.
• Achieve closure completion criteria, as confirmed by monitoring, to allow for effective and complete relinquishment of tenements.
• Fulfil all commitments in this Conceptual Closure Plan.
• Release SMC from further liability.
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As this Project is currently in the approvals phase, a Final Closure Plan is not feasible. This Conceptual Closure Plan proposes closure principles that will guide the management of mine landforms, water resources, revegetation, infrastructure and support facilities.
The Conceptual Closure Plan will be regularly updated throughout the anticipated initial 11 year mine life in order to consider the needs of stakeholders and address environmental impacts. A Final Closure Plan will be drafted at least two years prior to mine closure.
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1 INTRODUCTION
1.1 PURPOSE
SMC is an emerging iron ore producer in the Midwest Region of Western Australia. SMC is an incorporated entity established to conduct mineral exploration, engineering, environmental and economic studies into the feasibility to mine at Weld Range and, upon successful completion of these studies, implementation of the Project.
The Project is a direct shipping iron ore project with high grade outcrops over a 60 km strike length. Two ore bodies (Beebyn and Madoonga) have been identified at Weld Range, both of which are narrow and long with strike lengths in the order of 3 km. SMC is targeting to export 15 million tonnes per annum of iron ore over a 15 year period. The Public Environmental Review (PER) document addresses the first 11 years of planned operations.
This Conceptual Closure Plan outlines closure issues related to the infrastructure and activities incorporated with the mining, processing, and disposal of waste ore for the Project.
This document has been prepared to meet commitments made in the Weld Range Iron Ore Project Public Environmental Review, as follows:
Commitment 20:
A Conceptual Mine Closure Plan has been developed in alignment with AMEC Mine Closure Guidelines (2000) and ANZMECC Strategic Framework for Mine Closure (2000). During the life of mine, the plan will be reviewed and updated as required to ensure information remain current.
Commitment 21:
Twenty‐four months prior to mine closure, a Mine Closure Plan will be finalised in consultation with the DEC and DoIR. The plan will define appropriate closure criteria necessary for the establishment of safe landforms and self sustaining ecosystems, and set out procedures for monitoring in order to meet compliance with the closure criteria.
1.2 PROJECT DESCRIPTION
SMC proposes to develop the Project to initially mine and process approximately 15 million tonnes of direct shipping ore (DSO) per annum over 11 years. Mining will occur at two main deposits, namely Beebyn and Madoonga. The primary crushed ore from the pits will be transported via road train to the Central Processing Facility, located approximately midway between the pits and comprising road train unloading/tipping, screening, secondary crushing, stockyards and train load‐out. Other key items of infrastructure include an accommodation village, airport and interconnecting roads.
The extent of the land disturbance, including land cleared for associated infrastructure, will be approximately 4074 ha. Construction of the Project is expected to commence in 2012.
Fresh water produced from pit dewatering activities at Beebyn will be utilised in mine processing activities and saline water will be discharged via a pipeline to an evaporation pond in close proximity to the Madoonga Pit.
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The Project includes:
• two open pits;
• a central processing plant; (crushing and screening);
• ROM pads;
• dewatering infrastructure;
• evaporation pond;
• waste rock dumps;
• a tailings storage facility and washing plant;
• administration buildings;
• laboratory;
• workshops;
• airstrip and associated infrastructure;
• access roads, haul roads and tracks;
• storm water drainage;
• oily water treatment;
• RO plant;
• 18 dewatering bores;
• two power stations and a number of generators;
• Madoonga and Beebyn pit offices;
• hydrocarbon bulk storage facility;
• explosive storage facility;
• sewage plant; and
• an accommodation village.
Table 1.1 below highlights the key aspects of the Project. Figure 1.1 shows the site plan and the regional context of the Project.
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Table 1.1 – Key Aspects of the Weld Range Iron Ore Project
Key Aspect Description
Mining operations
Proposed operation commencement 2013
Project life span (this proposal) 11 years
Anticipated year of decommissioning for Beebyn and Madoonga
2024
Proposed mine locations Beebyn and Madoonga
Size of ore body 218.8 million tonnes (Mt) (dry, Beebyn and Madoonga)
Ore type Haematite / Goethite
Ore mining rate 15 Mtpa
Overburden mining rate 85 Mtpa (subject to final pit design) (wet)
Total product 137 Mt (Beebyn and Madoonga)
Stripping ratio (overburden: ore) 5.3:1
Total waste 723 Mt
Beebyn and Madoonga mining areas
Clearing for pits and overburden stockpiles 1811.5 ha
Madoonga pit details
Mining floor RL ~300 mRL
Water table RL ~480 mRL
Overburden stockpiles Overburden will be placed on the northern slopes of the range to minimise potential impacts to flora and fauna.
Beebyn pit details
Mining floor RL ~300 mRL
Water table RL ~480 mRL
Overburden stockpiles Overburden will be placed to minimise potential impacts to flora and fauna.
Processing equipment
Crushing, screening, stockpiling and rail car loading.
The ore will be crushed, screened and stockpiled as lump and fines iron ore prior to being re‐claimed and loaded onto railway wagons by an automatic rail car loader.
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Key Aspects Description
Processing requirements
Beneficiation (Future)
Lower grade fines ore will be stockpiled for future processing in a beneficiation plant to wash away the minus 63 micron material and any alumina above the marketable threshold for fines.
A tailings dam for rejected fines will be constructed.
The total area required for the tailings dam is estimated to be 46.5 ha.
Indicative dimensions: 280 m x 280 m x 5 m
Volume of tailings to dam 210,000 m3/a
Total solids deposited: 162,000 t/a
Assumed settled density: 2.0 – 2.5 t/m3
Volume of settled slimes: 64,800 – 81,000 m3/a
Dam capacity: 392,000 m3
Life: 11 years
Mine site infrastructure
Power source
On site diesel generator plant
The CPF will be powered by stand alone power station powered by 12 x 1 MW diesel generators.
Beebyn will be supplied by a 3 MW power station (installed capacity).
Madoonga will be supplied by a 3 MW power station (installed capacity).
The accommodation village will be supplied by a 2 MW power station (installed capacity).
The airstrip will be supplied with a 50 kW power station (installed capacity).
Water source From mine dewatering at Beebyn
Evaporation pond
3,000 m L x 1,100 m W x 1.3 m D;
area approximately 3.3 km2 and
0.3 m freeboard included.
Infiltration and evaporation
Anticipated annual water requirement
3.19 GLpa to 4.96 GLpa
Ancillary infrastructure
ROM pad (at Madoonga and Beebyn) for delivering ore from the mine
Mineral processing plant
Stacker and re‐claim equipment
Train load out facility
Administration and central facilities
Powerhouse
Magazines
Turkey nest dam
Airstrip and Accommodation village
Access roads
Borefield
Provision for future tailings dam (46.5 ha)
Estimated clearing area for infrastructure ancillary infrastructure
2188 ha
Total estimated clearing 4074 ha (40.7 km2)
Proposed Beebyn Pit
E51/907
E20/492
E20/625
E20/635
M20/403
M20/402
M20/311E20/625
E20/625
E20/641
E20/457
E20/625
E20/641
P51/2611
P20/2082
P51/2613P51/2612
P51/2610P51/2609
P51/2608P51/2607P51/2606
P51/2605
P20/2083P20/2084
P20/2085P20/2086
E20/633
E20/595
P51/2552
P20/2016
P20/2077
P51/2581
P20/2080
E20/633
E51/1354
M20/419
555000
555000
560000
560000
565000
565000
570000
570000
575000
575000
580000
580000
585000
585000
590000
590000
7015
000
7015
000
7020
000
7020
000
7025
000
7025
000
7030
000
7030
000
7035
000
7035
000
Map Reference: 852_WRPProjection Details: MGA 50, GDA 94Date: 18 Nov 2009
Proposed Alternative Infrastucture: Option 2³ 0 2 41
Kilometers
1:100,000@ A3
Legend
Access Road
Accommodation Village
Airstrip
Borrow Pit Area
Central Processing Facility
Haul Road
Primary Crushing & Screening Infrastructure
Beebyn Pit
Beebyn Waste Dump
Madoonga Pit
Madoonga Waste Dump
Midwest Live Tenements
Midwest Pending Tenements
Figure 1.1: WELD RANGE PROJECT
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1.3 TENEMENT INFORMATION
SMC is the applicant or registered holder of all of the Project tenements, except for Temporary Reserve 70/3902H (TR) which is discussed below. The Project tenements were applied for or granted pursuant to the Mining Act 1978 (WA). The Project tenements are detailed in Table 1.2 and comprise:
• three granted and two ungranted mining leases;
• nine granted and one ungranted exploration license;
• twenty granted prospecting licenses;
• one granted Temporary Reserve under a State Agreement (status further detailed below).
The TR 70/3902H was granted pursuant to the State Agreement scheduled to the Iron Ore (Murchison) Agreement Authorisation Act 1973 (WA) (State Agreement). Pursuant to the State Agreement, SMC was granted rights of occupancy in respect of the TR 70/3902H; these rights were periodically renewed by the relevant Minister until the 7th November 2008. These rights provided for the sole and exclusive purpose of searching and prospecting for iron ore. Following the Minister’s refusal to extend SMC’s rights of occupancy in respect of the TR 70/3902H, SMC applied for 14 prospecting licences over the land underlying the TR 70/3902H (Replacement Tenure). The Prospecting License Applications were lodged on 14th November 2008, and were granted by the WA Department of Mines & Petroleum on 5th March 2009 (see Table 1.3).
The land underlying the TR 70/3902H is currently exempt from Divisions 1–5 of the Mining Act. Accordingly, third parties cannot apply for an exploration license or any other type of tenement over the area underlying that land. As at the date of this report, SMC is only entitled to explore and prospect for iron ore and other minerals on the land underlying the Project tenements. SMC will not be able to mine iron ore or any other minerals unless one or more mining leases are granted over the land underlying the Project tenements.
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Table 1.2– Weld Range Tenements held by or applied for by SMC
Tenement Holder Area Date Granted
P51/2581 SMC 24 ha 11/03/2009
E20/595 SMC 1 block 04/05/2008
P51/2552 SMC 50.326 ha 26/10/2007
M20/419 Macdonald 507 ha Ungranted
E20/457 SMC 7 blocks 25/09/2006
E20/459 SMC 2 blocks 25/09/2006
E20/492 SMC 5 blocks 27/03/2007
E51/907 SMC 33 blocks 19/09/2006
M20/402 SMC 960 ha 27/08/1998
M20/403 SMC 991 ha 27/08/1998
TR70/3902 SMC 2,310 ha 06/10/1966
E20/635 SMC 4 blocks 06/02/2007
E20/633 SMC 2 blocks 05/03/2007
E20/641 SMC 3 blocks 10/08/2007
E51/1354 SMC 63 blocks Ungranted
E20/625 SMC 27 blocks 04/05/2008
P20/2077 SMC 23.8 ha 15/07/2009
P20/2078 SMC 23.8 ha 15/07/2009
P20/2016 SMC 48 ha 05/08/2009
P20/2080 SMC 23.5 ha 15/07/2009
M20/503 SMC 56.8 ha Ungranted
M20/311 SMC 834 ha 03/04/1996
Total
Sinosteel Midwest Corporation Limited (SMC) is listed as the tenement holder (or applicant) in all but one of the tenements in this table. SMC tenements are managed by Hetherington Exploration and Mining Titles Pty Ltd; whilst M20/419 is managed by the tenement holder Stanley Macdonald (SMC is the beneficial owner of this tenement).
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Table 1.3 – Prospecting Licenses Applied for in Substitution for TR 70/3902H
Tenement Holder Area
P51/2605 SMC 198.143 ha
P51/2606 SMC 198.148 ha
P51/2607 SMC 198.154 ha
P51/2608 SMC 198.160 ha
P51/2609 SMC 198.166 ha
P51/2610 SMC 198.171 ha
P51/2611 SMC 198.177 ha
P51/2612 SMC 198.183 ha
P51/2613 SMC 198.185 ha
P20/2082 SMC 195.214 ha
P20/2083 SMC 198.128 ha
P20/2084 SMC 198.041 ha
P20/2085 SMC 197.954 ha
P20/2086 SMC 197.868 ha
1.4 CONTACT INFORMATION
The following SMC personnel can be contacted regarding any queries with this Conceptual Closure Plan:
Head Office
Mr Wayne Ennor (Manager Project Approvals)
Sinosteel Midwest Corporation
PO Box 529
WEST PERTH WA 6872
Ph: (08) 9429 4888
Email: [email protected]
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2 CLOSURE OBJECTIVES
Planning for mine closure seeks to address the social, environmental, financial and safety aspects of mine closure. The purpose of mine closure is to prevent or minimise long‐term environmental impacts and to create a self‐sustaining natural ecosystem or alternate land use based on an agreed set of criteria (derived from the Australia and New Zealand Minerals and Energy Council (ANZMEC/MCA Strategic Framework for Mine Closure, 2000).
To meet this requirement SMC has adopted the ANZMEC/MCA objectives for mine closure, which are:
• To enable all stakeholders to have their interests considered during the mine closure process;
• To ensure the process of closure occurs in an orderly, cost effective and timely manner;
• To ensure the cost of closure is adequately represented in company accounts and that the community is not left with a liability;
• To ensure there is clear accountability and adequate resources for the implementation of the closure plan;
• To establish a set of indicators that will demonstrate the successful completion of the closure process; and
• To reach a point where the company has met agreed completion criteria to the satisfaction of the responsible authorities.
SMC are committed to fulfilling the above objectives, and in undertaking closure activities at the Weld Range project site, SMC will fulfil the following project specific objectives:
• Ensure, as far as practicable, that rehabilitation achieves a long term, safe, stable and functioning landform which is consistent with the surrounding landscape and pre‐existing environmental values.
• Conduct effective consultation to enable stakeholders, including regulatory agencies, non‐government organisations and other interested parties, to have their interests considered during the mine closure process.
• Ensure that commitments made to stakeholders and regulators are fulfilled.
• Ensure that public safety is protected.
• Minimise negative impacts to the surrounding environment.
• Ensure legislative requirements are met.
• Re‐establish landforms and vegetation communities to meet the agreed post‐mining land use requirements.
• Achieve closure completion criteria, as confirmed by monitoring, to allow for effective and complete relinquishment of tenements.
• Fulfil all commitments in this Closure Plan.
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The Project closure objectives will be achieved by:
• Establishing, through survey and investigation, a baseline of the environment prior to project disturbance.
• Allocating appropriate cost and resource provision requirements.
• Planning mining and associated activities to best fit with closure concepts.
• Consulting with stakeholders to determine post closure land use and completion criteria for the project areas.
• Undertaking environmental monitoring to ensure that rehabilitation techniques have been successful in achieving post closure land‐use criteria.
2.1 END LAND USE
Final land use is expected to comprise of pastoralism with some restricted zones to ensure the future safety of people and wildlife.
The landscape will comprise rehabilitated waste and fines rejects stockpiles, with final slopes ensuring long‐term stability, a mine pit that will form pit lakes. Surface drainage will be reinstated where possible or diverted to reduce the likelihood of ponding after heavy rains.
SMC will undertake further community consultation to develop and define the end land use options for its operations and also undertake environmental, social and economic assessments to ensure the selected options are sustainable.
An overview of the conceptual options for closure and rehabilitation of the major mining features is provided in the following sections.
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3 BASELINE ENVIRONMENTAL DATA
3.1 CLIMATE
3.1.1 Bioregions and Major Physiographic Units
The Interim Biogeographic Regionalisation for Australia (IBRA) categorises the Australian continent into regions of similar geology, landform, vegetation, fauna and climate (IBRA, 2000). The Weld Range lies in the Murchison Biogeographic Region, Western Murchison sub region which lies within the Eremaean botanical province or the arid zone of Western Australia, as illustrated below in Figure 3.1.
Figure 3.1 – Western Murchison Subregions and SurroundsL MUR1 – Eastern Murchison, MUR2 ‐ Western
Murchison (Based on IBRA Version 6.1 Thackway and Cresswell 1995).
The Western Murchison subregion comprises predominately Mulga (Acacia aneura) low woodlands, with an understorey often rich in ephemerals (usually with hummock grasses). The substrate consists primarily of outcrop and fine textured Quaternary alluvial and eluvial surfaces (extensive hardpan wash plains that dominate and characterise the subregion) mantling granitic and greenstone strata. Where occluded drainage features occur, vegetation is dominated by saltbush shrub lands on calcareous soils and Halosarcia low shrub lands on saline alluvia. The Western Murchison subregion contains the headwaters of the Murchison and Wooramel Rivers, which drain the subregion westwards to the coast.
Grazing of native pastures accounts for most land use, although unoccupied Crown land, conservation reserves and mining are also significant land uses (Thackway and Cresswell, 1995).
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3.2 CLIMATE AND METEOROLOGY
Meteorological data has been recorded at the Bureau of Meteorology (BOM) weather station at Meekatharra airport.
Climate
Weld Range is located in the Midwest region of WA, approximately 80 km west south‐west of Meekatharra. The region experiences hot, dry summers and mild winters. A high pressure band or subtropical ridge dominates the weather pattern throughout the year. During the warmer months, a low pressure trough is located to the south, resulting in southerly and south‐easterly winds. Occasional cold fronts bring little rain to the region whereas tropical cloud bands bring the most rains during the winter months.
Temperature
Mean maximum temperatures range from 38.2°C in January to 19°C in July. Mean minimum temperatures range from 24.3°C in January to 7.4°C in July. Very hot summers and mild winters are representative of the region (Figure 3.2).
Rainfall
The late summer and early winter months (February and June) provide the most rainfall over the year (Figure 3.2). The total annual rainfall in this region is very low (less than 250 mm per annum). September is the driest month of the year, receiving on average less than 5 mm of rainfall over the entire month. This dry environment has the potential to result in higher particulate emissions from mining activities.
Figure 3.2 – Summary of Climatic Data for Meekatharra Airport (BOM, 2009).
Relative Humidity
The morning (9 am) mean relative humidity is consistently higher than the afternoon (3 pm) mean. On average, humidity increases to between 41% and 63% in the winter months and decreases to between 16% and 28% in the summer months. This low humidity can increase the potential for higher particulate emissions from mining activities.
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Winds
The seasonal and annual wind roses for Meekatharra indicate the following:
• for January to March, eastern and south‐eastern winds are predominant;
• for April to June, the main winds are from the east;
• for July to September, the winds are primarily from the east or south; and
• for October to December, the wind pattern is similar to July to September but the wind speed is generally higher.
The overall wind speed rages between 2 m/s and 5 m/s. The frequency of wind speeds between 5 m/s and 10 m/s reduces gradually to the point that very few hours have an hourly average wind speed greater than 10 m/s.
3.3 GEOMORPHOLOGY
3.3.1 Topography
The topography of the area is dominated by the Weld Range – a long band of steep ridges that run southwest to northeast and extend over a distance of more than 60 km. The Project tenements are situated within these ridges. The elevation ranges from approximately 460 m to 730 m RL. The slope angles in the area of the Weld Range vary from less than 5 % to greater than 90 %. Away from the ridges the topography is very flat.
There are some clearly delineated drainage channels within the Weld Range itself, however the land to the north has only few well defined channels and is characterised by numerous mud flats and salt pans. There is a significant salt pan in a depression immediately north of the Madoonga tenement. The available topographic data indicates a minimum elevation of 482.7 mAHD in this salt pan.
3.3.2 Banded Ironstone Formation
The BIF ranges of the Midwest are of very significant biodiversity value because of their unique geology, soils and relative isolation. The values of the ranges are related to the presence of endemic plant species, rare and restricted plant species and highly restricted and distinct plant communities and ecological communities. The ranges are also very distinct features in their regional landscape and in many cases possess outstanding landscape values. They also have fauna conservation values although these are less well documented than for flora. There are, however, differences between the various BIF ranges in terms of their biodiversity conservation and mineral prospectively/resource values.
3.4 LAND SYSTEMS AND SOILS
Curry et al. (1994) undertook a regional survey of the Murchison River catchment and surrounds to document and prepare an inventory of the land systems present and the conditions of each. The area surveyed (88,360 km2) was situated between Meekatharra and Mount Magnet to the east, and the catchments of the Greenough and Wooramel Rivers in the west.
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Most of the surrounding area within the Project lies within the Yarrameedie, Violet and Jundee land systems, with smaller areas of the Sherwood, Mileura, Norie, Cunyu, Kalli, Gabanintha, Breberle, Koonmarra, Waguin, Wiluna, Yandil and Yanganoo land systems also present. These land systems
The Weld land system is described as rugged ranges and ridges of mainly Archaean metamorphosed sedimentary rock supporting acacia shrublands (Curry et al. 1994). It is 350 km2 in area and consists of two distinct and widely separated localities ‐ Weld Range and Jack Hills.
The Yarrameedie system is largely associated with the Weld system in the Project area. It is described as undulating stony interfluves, drainage floors and pediment (foothill) plains below major ranges of crystalline rocks (mainly Weld land system) supporting sparse Mulga shrublands (Curry et al. 1994). The two other major land systems in the project area, the Violet and Jundee land systems, both support scattered Mulga shrublands over plains. They both occur on the plains below the Weld Range.
The Mileura land system is unique in the Project area as it consists of seasonally inundated claypans supporting halophytic shrublands. These shrublands form unique habitats with species such as Slender‐billed Thornbill and White‐winged Fairy‐wren restricted to these habitat types.
The weathering of the Archaean and overlying Proterozoic rock has been occurring since the tertiary period, producing the sediments that form the soils of the surrounding plains. The soils therefore vary from shallow, stony soils and loams on the rocky slopes of the hills and ridges, to deeper, red earths on the lower slopes and outwashes. These outwashes are derived from the weathering of the parent rock and include the calcareous soils from the mafic rock. They are characteristically infertile and acidic (Markey & Dillon, 2006).
3.5 GEOLOGY
3.5.1 Regional Geology
The Weld Range is found on the northern extent of the Yilgarn Craton. The Yilgarn Craton is described by Curry et al. (1994) as a gently undulating landscape, composed of Archaean rocks, dominantly granite with north to northwest trending belts of greenstone rocks. These greenstone rocks form hill ranges which are separated widely by the very flat plains derived from colluvium and alluvium. Soils are mainly shallow, sandy and infertile, and across most of the lower areas are distinctively underlain by red‐brown siliceous hardpan.
The Weld Range is one of the several linear greenstone belt ridges representing the northern extent of the Yilgarn Craton. It is composed dominantly of Hematite (red), Magnetite (black) and Silica (white) BIF rock, embedded with Dolerite, Jaspilite and greenstone, a type of metamorphic rock that owes its colour to the presence of a green mineral such as chlorite. BIF is erosion resistant and forms the rocky outcrops and steep ridges that are characteristic of the Weld Range. The mineralization of BIF is resultant in the formation of iron ore and as a result, these ranges have developed significant deposits (Markey & Dillon, 2006).
3.5.2 Geology of Madoonga and Beebyn
Steeply dipping, east‐northeast‐striking BIFs are known to occur in three ridges at Weld Range: the North, Central and South Ranges. The BIFs are interleaved with metabasic rocks that show doleritic and lesser basaltic and gabbroic textures. The BIFs within the North, Central and South Ranges are referred to as the Madoonga, Lulworth and Wilgie Mia beds, respectively. Iron mineralisation within the three ranges is not continuous and occurs as 44 distinct iron ore lenses, named W1 to W44. Of
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these 44 lenses, the Madoonga (W14) and Beebyn (W7, W8, W9, W10 and W11) ore bodies form the focus of this PER.
The Madoonga deposit contains a steeply south‐southeast‐dipping rock sequence that comprises, from north to south, felsic sedimentary rocks, and a 60 to 250 m thick BIF and a 20 to 50 m thick zone of deeply weathered and altered rocks within which the iron mineralisation is hosted. Sediments and sedimentary rocks lie above an erosional unconformity on the iron mineralisation and deeply weathered rocks. The sedimentary rocks comprise ferruginous conglomerate and pisolitic gravels that have a thickness up to 20 m and locally have high Fe grades (>60% Fe).
The Beebyn deposit contains numerous steeply southeast dipping BIFs interlayed with dolerite, of which the most economically important is approximately 40 m thick. Least altered and unweathered BIFs contain millimetre to centimetre thick bands rich in iron, silica and Fe‐silicate and sone of the bands are carbonate rich. These mineralised zones are offset by up to 100 m by late sub vertical northwest striking faults (SRK, 2010).
3.6 GROUNDWATER
3.6.1 Regional Hydrogeology
The Weld Range area is located within the East Murchison Groundwater Management Unit. Groundwater occurs at relatively shallow depths (typically 5 – 50 m bgl) beneath the alluvial plain around Weld Range, and occurs within the bedrock sequence that forms Weld Range. Recharge to the system occurs from rainfall infiltration mainly through creek beds and to a lesser extent on floodplains. Some groundwater recharge can be expected through the creek beds between the ridges that form Weld Range.
Two main types of aquifers can be identified around the Weld Range:
1. Shallow aquifers located in the superficial sediments:
• Quaternary sediments that overly calcrete, palaeochannels, and fractured rock: these sediments are not known to be major aquifers, and are only utilised by wells and boreholes for stock watering. The groundwater is neutral to alkaline with a high salinity.
• Tertiary limestone and calcrete sediments: these sediments have the highest potential for shallow water supply. The groundwater is alkaline with pH greater than 8 and is hyposaline.
• Tertiary palaeochannels sediments: these sediments may have the potential to contain large volumes of alkaline and saline groundwater.
2. The fractured and weathered rock aquifers are located in the rocks of low primary permeability. They are currently the main source of water in the areas and the borehole yields vary from near zero to a possible several hundred cubic metres per day. The main groundwater yielding zones within this sequence are associated with vuggy and cavernous zones, and larger scale structures (along fault and shear zones). This groundwater is normally acidic to neutral, with a low salinity.
3.6.2 Project Hydrogeology
As part of the Prefeasibility Study for the Project, SRK conducted a comprehensive hydrogeological investigation in 2007 and 2008. SRK completed further fieldwork between March and November
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2009 to provide additional hydrological data to enhance the regional understanding of the hydrological setting around the Project.
A borehole and well survey was performed in a 30 – 40 km radius area around the Weld Range to collect baseline hydrogeological information that included water levels, pH and conductivity (SRK, 2010). A total of 58 boreholes and wells were included in this survey. Parameters were measured in selected locations approximately every four months to allow a comparison of data to be made and an assessment of any changes in aquifer conditions.
Extensive investigations were also performed in the proposed pit areas of Beebyn and Madoonga. Structural logging of 29 drill holes in Beebyn and 24 drill holes in Madoonga (totalling approximately 11,500 m) provided additional insight to rock conditions (SRK, 2010a).
The Prefeasibility Study conducted by SRK determined areas of insufficient knowledge. The bankable feasibility Study fieldwork investigations were developed to address the identified gaps and were conducted between March 2009 and November 2009 to provide the outstanding hydrogeological data.
Extensive investigations were performed in the proposed pit areas. Structural logging of eight geotechnical drill holes in Beebyn and 11 in Madoonga (totally approximately 4,500 m) provided additional insight to rock conditions.
All the information gathered during the field investigation was compiled to construct a preliminary conceptual hydrogeological model of the area. A total for seven hydrogeological units were determined and the spatial distribution of these unites were defined. Three units contain most of the groundwater generated in the Project area. On a regional scale, the unconsolidated sediments that cover all the flatlands north and south of the range provide water for agricultural activities in the area. A significant palaeochannel was identified in The Gap area. This palaeochannel itself is relatively impermeable. However, a fracture zone located below the palaeochannel is believed to be highly permeable and could contribute considerable inflow into the Madoonga pit. The third unit holding significant amounts of groundwater is the BIF. Drilling through this unit proved challenging as large amount of water were encountered because of the high hydraulic conductivity values and high storage capacity. Pumping tests performed in his unit confirmed these observations and geochemical observations confirmed that recharge is higher in the BIF aquifer than in the unconsolidated sediments.
The conceptual model was used as a basis for constructing a numerical groundwater model, which was then constructed using FEFLOW®. The entire Project area was modelled, all the identified hydrogeological units were incorporated into the model and properties derived from the hydrogeological investigations were assigned to the units (SRK 2010a).
3.6.2.1 Hydrogeological Characterisation
Water level and quality data (pH and Total Dissolved Solids (TDS)) were collected three times during the Prefeasibility Study (PFS) investigations. Groundwater samples from regional boreholes were taken and analysed in July/August 2007 and June 2008. This sampling programme was developed to provide initial data for a monitoring programme for the Project.
The regional borehole survey was repeated for the BFS in November 2009. The data collected during the survey in October/November 2009 was used for updating a conceptual model and calibration of the groundwater model. A total of 58 boreholes and wells were surveyed during the investigation. These boreholes were located in the catchment surrounding Weld Range on Beebyn, Glen and
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Madoonga pastoral stations. The depth of the wells and boreholes varied from 2.36 to 23.39 m bgl. They were all placed in the shallow aquifer.
Regional Groundwater Levels
The water level contour map of November 2009 indicates a movement of the groundwater from the north towards the southeast following the tertiary palaeochannels drainage direction. The regional water elevations range between 510.15 m RL (Outcamp Well) along the northern margin to 427.15 m RL (7 Mile Well) along the southern margin of the investigated areas, the wells are 45 km apart (SRK, 2010).
Water level contour maps in the Madoonga and Beebyn areas indicate slightly elevated groundwater levels. The elevation of the water level mound in the Weld Range ranges from 482.24 to 507.78 m RL. The dominant foliation and dolerite intrusions in the Weld Range strike across the general drainage direction of the groundwater. Because of the low permeability of the dolerite, a mounding of the water on the northern side of the range is expected, except where a preferential pathway has been formed by cross‐cutting structural features (e.g. The Gap at Madoonga).
Regional Groundwater Salinities
Contouring of the groundwater salinity data indicates that the regional groundwater is fresh (TDS< 500 mg/l) to marginal (500<TDS<1,500 mg/l), except in the boreholes or wells located in the palaeochannels. The areas of higher groundwater salinity correspond to lower topographic areas and surface drainage systems. The higher salinity in these surficial aquifers due to the shallow water table and the high evaporation rate of the area; the water evaporates as soon as it reaches the surface or even in the vadose zone just below the surface. This results in the deposition of numerous minerals and salts in and around the lower topography areas and subsequently increases the salinity of the immediate groundwater. When this occurs the water quality then becomes brackish (1,500<TDS<5,000 mg/l) varying from 2,643 mg/l (7 Mile Well) to 4,900 mg/l (Gap Bore) to saline with the highest salinity measured at MDWB01 (48,000 mg/l), M_WBG_01R (46,000 mg/l) and M‐LTM‐04 (35,000 mg/l). The boreholes that have the highest salinity reflect the proximity of these boreholes to the Tertiary palaeochannel (SRK 2010a).
3.7 BIOLOGICAL
3.7.1 Flora
To date, 27 priority taxa have been recorded in surveys carried out by ecologia and the DEC at Weld Range. These priority flora species are located across a range of vegetation communities and landforms and include six Priority 1, 18 Priority 3 and three Priority 4 species. Table 5‐3 summarises the distribution of these taxa.
The conservation significance of two land systems occurring within the Project area ‐ Weld and Yarrameedie – is rated as regionally significant as they are mapped over small areas of Western Australia and the Murchison.
Three of Beard’s vegetation units ‐ Acacia aneura and Acacia quadrimarginea scrub (a 1.14 Si), Acacia aneura and Acacia grasbyi low woodland (a 1.17 Li) and Acacia aneura, Acacia ramulosa and Acacia linophylla (now Acacia ramulosa var. linophylla) low woodland (a 1.9 Li) ‐ are considered to have high regional significance due to their limited distribution in Western Australia.
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One of the vegetation units recorded by the DEC at Weld Range is regionally significant – Community 6 ‐ Acacia sp. Weld Range, A. aneura and A. speckii shrubland over Eremophila spp. and Heliotropium ovalifolium on dolerite.
Three vegetation units mapped by ecologia during the current survey are considered to have high local conservation significance. Communities 1 and 2 and their associated sub‐communities are restricted to the BIF ridges and outcrops, which are the target of mining activities. Community 4 (and associated sub‐communities) appears to be the only known community in which the two undescribed species of interest, Acacia sp. nov. (aff. kochii) and Hemigenia sp. nov. (aff. exilis), occur. Community 7 (and associated sub‐communities) has a limited distribution in the Project area and is the only recorded habitat for the priority three species Tecticornia cymbiformis at Weld Range.
3.7.2 Vertebrate Fauna
Fives conservation significant fauna species have been recorded in the project area:
• Long‐tailed Dunnart (Sminthopsis longicaudata) (DEC Priority 3);
• Peregrine Falcon (Falco peregrinus) (WCA Schedule 4);
• Bush Stone‐curlew (Burhinus grallarius) (DEC Priority 4);
• Slender‐billed Thornbill (Acanthiza iredalei) (EPBC Act Vulnerable); and
• A fossorial skink (Lerista eupoda) (DEC Priority 1).
3.7.3 Invertebrate Fauna
Forty five invertebrate species of interest were collected from the Weld Range SRE survey. These included eight species of scorpions, six species of pseudoscorpions, 15 species of mygalomorph spiders, one species of millipede, 10 species of centipedes, four species of isopod and one species of land snail. The most important species identified as either being likely to represent SRE species or belonging to the category of protected fauna under the Wildlife Conservation Act (1950) were:
• the Shield‐back Spider; Idiosoma nigrum (Schedule 1 species; Mygalomorph spider);
• Aurococrypta lugubris (Mygalomorph spider);
• Cethegus ‘fugax complex’ (Mygalomorph spider);
• Pleuroxia sp. (land snail); and
• Antichiropus sp. ‘Weld Range’ (Millipede).
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4 LEGAL OBLIGATIONS
Mine closure is subject to both federal and state legislation and SMC is required to meet legal obligations during design, operation and closure phases of the Project.
The Weld Range Iron Ore Project is being assessed by the Department of Mines and Petroleum (DMP) under the Mining Act 1978 and by the Environmental Protection Authority under the Environmental Protection Act 1986 through a Public Environmental Review. This Conceptual Closure Plan is consistent with the environmental objectives outlined in the Weld Range Iron Ore Project PER document.
This plan aims to incorporate requirements under the Mining Act 1978 and fulfil the conditions placed on SMC’s tenements.
Additional legislation that may be applicable to mine closure is included in Table 4.1.
Table 4.1 – Legislation Applicaple to the Project.
Legislation Responsible Government Agency
Commonwealth Legislation
Environmental Protection and Biodiversity Conservation Act 1999
Department of Environment and Heritage
Native Title Act 1993 National Native Title Tribunal
Protection of Moveable Cultural Heritage Act 1986
Protection of Moveable Cultural Heritage Act 1986
National Greenhouse and Energy Reporting Act 2007
Department of Climate
Change
State Government Legislation
Aboriginal Heritage Act 1972 Department of Indigenous Affairs
Agricultural and Related Resources Protection Act 1976
Department of Agriculture, Western Australia
Bush Fires Act 1954 Bush Fires Board
Conservation and Land Management Act 1984 Department of Environment and Conservation
Contaminated Sites Act 2003 Department of Environment and Conservation
Country Areas Water Supply Act 1947 Department of Industry and Resources
Dangerous Goods Act 1961 Department of Industry and Resources
Dangerous Goods Regulations 1992 Department of Consumer and Employment Protection
Environmental Protection Act 1986 Department of Environment and Conservation
Explosives and Dangerous Goods Act 1961 Department of Industry and Resources
Explosives and Dangerous Goods (Dangerous Goods Handling and Storage) Regulations 1992
Department of Industry and Resources
Health Act 1911 Department of Health
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Legislation Responsible Government Agency
Heritage of Western Australia Act 1990 Heritage Council of Western Australia
Mining Act 1978 Department of Industry and Resources
Mines Safety and Inspection Act 1994 Department of Consumer and Employee Protection
Occupational Safety and Health Act 1984 Department of Consumer and Employment Protection
Public Works Act 1902 Department of Housing and Works
Rights in Water and Irrigation Act 1914 Department of Environment and Conservation
Soil and Land Conservation Act 1945 Department of Agriculture, Western Australia
Waterways Conservation Act 1976 Department of Environment and Conservation
Wildlife Conservation Act 1950 Department of Environment and Conservation
4.1 GUIDELINES AND CODES OF PRACTICE
The Guidelines and Codes of Practice outlined below were used in the preparation of this document, and contain material relevant to this Closure Plan are outlined in Table 4.2.
Table 4.2 – Guidelines and Codes of Practice.
Aspect Guidelines
General/ Closure
ANZMEC/MCA (2000), Strategic Framework for Mine Closure. Australian and New Zealand Minerals and Energy Council and Minerals Council of Australia. Canberra, ACT.
Chamber of Minerals and Energy of Western Australia Inc (1999) Mine Closure Guidelines for Minerals Operations in Western Australia.
Department of Industry and Resources, (2006). Guidelines for Mining in Arid Environments.
Department of Industry and Resources, (2006). Guidelines for Mining Proposals in Western Australia.
Minerals Council of Australia (2000) Code for Environmental Management.
Department of Tourism, Industry and Resources, (2006). Mine Closure and Completion: Leading Practice Sustainable Development Program for the Mining Industry.
Ministerial Council of Minerals and Petroleum Resources, Minerals Council of Australia (2003). Strategic Framework for Tailings Management.
EPA Guidance No. 33 (2008). Environmental Guidance for Planning and Development.
Department of Mines and Energy, (1997). Safety Bund Walls around Abandoned Open Pit Mines.
Department of Industry and Resources (2009) Environmental Notes on Mining – Care and Maintenance September 2009.
Water
Water and Rivers Commission, (2000). Mine Void Resource Issues in Western Australia.
Department of Water, (Draft, February 2009). Pilbara Water in Mining Guideline.
National Health and Medical Research Council (2004). Australian Drinking Water Guidelines.
ANZECC / ARMCANZ (2000). Australian New Zealand Guidelines for Fresh and Marine Water Quality.
Water and Rivers Commission (2000). State‐wide Policy No. 5 Environmental Water Provisions for Western Australia.
EPA Position Statement No. 4. Environmental Protection of Wetlands.
Tailings and Waste
Department of Industry and Resources (2001). Environmental Notes on Mining Waste Rock Dumps.
Department of Industry and Resources (1999) Guidelines on the Safe Design and Operating Standards for Tailings Storage.
Department of Tourism, Industry and Resources (2007). Tailings Management.
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Aspect Guidelines
Water and Rivers Commission (2000). Water Protection Guidelines No. 2‐ Mining and Mineral Processing‐ Tailings facilities.
Australian Standard 1940 – The Storage and Handling of Flammable and Combustible Liquids (AS 1940‐1993)
Rehabilitation
Australian Mining Industry Council (1989), Mine Rehabilitation Handbook.
Department of Tourism, Industry and Resources, (2006). Mine Rehabilitation: Leading Practice Sustainable Development Program for the Mining Industry.
Environment Australia (1998). Landform Design for Rehabilitation.
Flora and Fauna
National Strategy for Ecologically Sustainable Development (1992) Commonwealth of Australia.
EPA Position Statement No. 6: Towards Sustainability.
EPA Guidance Statement No. 55 Implementing Best Practice in proposals submitted to the EIA process.
EPA Position Statement No 3: Terrestrial Biological Surveys as an element of Biodiversity Protection.
EPA Position Statement No. 2 Environmental Protection of Native Vegetation in WA.
EPA Position Statement No. 9 Environmental Offsets.
EPA Guidance Statement No. 51. Terrestrial Flora and Vegetation Surveys Environmental Impact Assessment in WA.
EPA Guidance Statement No. 54. Consideration of Subterranean Fauna in Groundwater and Caves during EIA in WA.
EPA Guidance Statement No. 3. Separation Distances between Industrial and Sensitive Land Uses.
EPA Guidance Statement No. 56. Terrestrial Fauna Surveys for Environmental Impact Assessment in WA.
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5 POLICY
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6 STAKEHOLDER CONSULTATION
ANZMEC (2000) highlights the importance of enabling all stakeholders to have their interests considered during the closure process.
SMC has been in consultation with key government agencies, Non‐Government Organisations (NGOs) as well as the local communities since the commencement of the feasibility studies.
Further consultation with government agencies, the general public, private landowners, interested NGO’s and other stakeholders will continue throughout the operation of the mine and closure process. The closure process will not be viewed as complete until commitments made by SMC to stakeholders concerning site closure have been met.
Stakeholders identified as having an interest in the Weld Range Iron Ore Project are listed in Table 6.1.
Table 6.1 – Stakeholder Consultation.
Stakeholder Department Name
DPI ‐ Statutory Planning Div. Peter Zadien
DPI ‐ Land Titles Nick Schoeffer, Steve Burgess
DoIR ‐ Investment Facilitation Peter King
DoIR ‐ Minerals Karen Pye, Andrew Bartleet
DoH ‐ Environmental Health Dianne Katcherian
DoCEP ‐ Major Hazards Richard Craddock, Anil Atri
DIA Richard Riordan, Denis Callaghan
EPA Service Unit Andrew Napier, Sue Osborne
DEC ‐ Environment Division ‐ Geraldton Beth Mckernan
DEC ‐ Parks and Conservation Div. Nick Woolfrey, Norm Caporn
DEC ‐ Environment Division‐ Part V Peter Skitmore, Danielle Ayre, Emma Jones
DoW Susan Worley
Cue Shire Brian Seal
Wildflower Society of WA Bryan Moyle
Native Title Claimants Wajarri Yamatji
Landowners David Leach ‐ Beebyn Station, Zane and Carolyn Day – Madoonga Station, Morrie Sievwright – Glen Station.
Conservation Council of WA Tim Nicol
The Conceptual Closure Plan will be reviewed based on input from stakeholders to ensure all parties are agreed on final land use, decommissioning and rehabilitation procedures.
A copy of the Conceptual Closure Plan will be publicly available as part of the Project PER.
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7 PLANNING
A key objective of ANZMEC (2000) is to ensure that the process of closure occurs in an orderly, timely and cost‐effective manner.
Mine closure should be integral to the life‐of‐mine plan, should reflect a risk‐based approach and should be reviewed and updated as required. SMC have ensured that mine closure strategies have been incorporated into each stage of the planning process, from planning and design, to construction, operations and decommissioning.
SMC has undertaken extensive public consultation (Section 6) throughout the planning stage of the proposal concerning final landforms, and all Weld Range work areas and associated construction will be in compliance with the appropriate legislation.
Mine infrastructure including haul roads, plants, administration buildings, workshops, water supply, the TSFS and overburden stockpiles have been planned to consider the following, which may influence the success of mine closure:
• alignment with natural topographic landforms in the area;
• use of pre disturbed areas to minimise the impact of clearing on native vegetation;
• consideration of natural drainage lines and flooding zones;
• minimise impacts on groundwater levels and quality;
• avoidance of conservation significant flora;
• avoidance of Schedule 1 Idiosoma nigrum populations; and
• avoidance of indigenous heritage sites.
7.1 RISK ASSESSMENT
A comprehensive risk assessment was undertaken to inform all environmental impact assessment documentation. The risk assessment was completed in April 2009.
The assessment highlighted the following as having the potential to influence mine closure:
• waste landform (waste rock stockpiles, tailings storage facility) design and location;
• contamination from pit lakes;
• topsoil storage;
• impacts of mine infrastructure to surface water flows and water quality during flood events;
• impacts to surface water and surrounding environment from dewatering and surplus water disposal;
• vegetation disturbance and weed dispersal;
• progressive rehabilitation with appropriate species; and
• financial provisioning for mine closure.
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Consequently preliminary controls have been developed (and described in Section 9 and 10) to manage the extent to which these factors may impact on closure objectives and completion criteria.
SMC have developed, and will use, the following ‘hierarchy of control’ methodology in planning for project closure:
• elimination of risk;
• substitution with a lower risk;
• engineering to reduce the impact of the risk;
• administrative procedures and training; and
• remediation to mitigate impacts.
7.2 PROJECT CONDITION REPORTS
In order to appropriately determine closure objectives, surveys and investigations have been conducted including:
• flora and fauna surveys including stygofauna, troglofauna and short range endemics;
• hydrogeology assessments on the impact of groundwater extraction, surface water flows and water quality;
• geochemical and physical analysis of waste rock material; and
• heritage studies including archaeological and ethnographic heritage surveys.
The data gathered from these assessments has been used to develop this Conceptual Closure Plan.
7.3 COMPLETION CRITERIA AND PERFORMANCE INDICATORS
Completion criteria are an agreed set of environmental indicators, which upon being met, will demonstrate that agreed outcomes have been achieved and hence the site may be deemed closed. These criteria are inextricably linked to management and monitoring programmes.
SMC will consult with all stakeholders and interested parties throughout the life of the Project to ensure the agreed completion criteria are and / or will be met, or alternatives agreed to as necessary.
The Strategic Framework for Mine Closure published by ANZMEC/MCA (2000) states that completion criteria should:
• Reflect the specific environmental and socio‐economic circumstances of the site.
• Be flexible enough to adapt to changing circumstances without compromising the agreed end objective.
• Undergo periodic review and modification in light of improved knowledge or changed circumstances.
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The proposed completion criteria for the Project have been developed, taking into consideration the following factors:
• public health and safety;
• regulatory requirements;
• SMC’s Environmental Policy;
• expectations of stakeholders;
• geotechnical stability and the suitability of final landforms;
• sustainability of revegetated areas and surrounding ecosystems;
• no unapproved disturbance of heritage areas; and
• post‐closure land use objectives.
The closure criteria and interim rehabilitation targets are summarised in Table 7.1 below, and detailed aspects are contained in the remaining sections of this document.
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Table 7.1 – Closure Criteria
Aspect Objective Interim Rehabilitation Target
Final Landform
C1: Final landforms will be developed such that they will remain structurally and chemically stable, safe to humans and provide a sustainable habitat for flora and fauna without ongoing maintenance.
C2: Landforms will conform to the requirements of agreed post‐closure land use.
C3: Access to pit lakes will be prohibited to ensure pit lakes are safe to humans and to minimise the occurrence of fauna mortality.
Safety and abandonment structures are in place and final landforms have been shaped to design criteria.
Contamination
C4: There shall be no contamination of groundwater, surface water and surrounding environment from the inappropriate storage or handling of chemicals and hydrocarbons.
C5: Known contaminated sites are remediated to agreed levels as soon as possible.
Conduct an ongoing ground and surface water monitoring program that demonstrates pollutant levels at potentially contaminated sites are within regulatory requirements.
Surface Water C6: No change in the long term quantity or quality of surface water, so that existing and potential environmental values, including ecosystem maintenance are protected.
Monitoring program for surface water indicates no reduction in quality as compared to pre‐disturbed state.
Diversion drains, surrounding the mine pits, will be in tact following mine closure
Ground Water C7: The quality and quantity of ground water is maintained, so that existing and potential environmental values, including ecosystem maintenance are protected.
Monitoring program for ground water indicates no reduction in level and quality as compared to pre‐disturbed state.
Decommissioning C8: All project infrastructure that is not required for post closure land use will be removed or disposed of appropriately.
Infrastructure has been removed and rehabilitation commenced to simulate the pre‐disturbance state as closely as possible.
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Aspect Objective Interim Rehabilitation Target
Visual Amenity and Heritage
C9: Ensure that aesthetic values and public interaction with the landscape are considered, and measures are adopted to reduce the visual impacts on the landscape.
C10:Maintain and protect any significant landscape, indigenous heritage and geo‐heritage values.
Progressively integrate rehabilitated areas with the natural environment.
Rehabilitation of Native Vegetation and Topsoil
C11: Impacted areas are returned to self‐sustaining vegetation communities and fauna habitats that reflect pre‐disturbed state.
C12: Weed species cover is identified and contained to minimise spread into weed free areas.
C13: Topsoil remains viable and has the capacity to support a safe, stable and functioning ecosystem that meets the requirements of the post‐mining land use, where it exists.
Deep ripping has been conducted in rehabilitation areas.
Flora species have been identified for use in rehabilitation and seed collection where possible, and reflect principles of vegetation succession.
Permanent photographic record points and monitoring/analog transect locations have been defined.
Fencing has been erected around rehabilitation target areas to quarantine them from grazing
Adequate topsoil and subsoil material has been provided for progressive rehabilitation where possible..
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7.4 TARGETED RESEARCH
Research, where feasible and required, will be conducted to investigate the following:
• geotechnical and erosion control monitoring;
• groundwater monitoring;
• surface water monitoring;
• rehabilitation monitoring; and
• physical and chemical soil testing.
Research into the Idiosoma nigrum Population Genetic Study will be carried out prior to construction commencing and during the life of the Project. The study will assist in the management of each population as a separate entity, ensuring maximum genetic diversity and that rehabilitation associated with the Project takes into account mechanisms of recolonisation.
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8 FINANCIAL PROVISION
Provision of adequate financial resources for closure is critical in order to ensure that all closure requirements are reached, as agreed via consultation, and to finalise the Project without leaving residual company or community liability.
The ANZMECC Strategic Framework for Mine Closure (2000) objective for closure costing is to ensure the cost of closure is adequately represented in company accounts and that the community is not left with a liability. ANZMEC (2000) also states that clear accountability and adequate resources must be provided for the implementation of the closure plan.
Planning for closure commenced in the feasibility stage and will continue throughout the life of the mine.
8.1 COST ESTIMATE
Table 8.1 details a conceptual cost estimates for closure for the Project, which are based on bond calculations. Cost estimates will be developed in detail during the Operational Closure Plan to include progressive rehabilitation, final closure activities, monitoring and long‐term site management. These estimates do not include return on sale of assets or costs recovered from salvage of materials.
Development of a final closure cost model will incorporate the following actions:
• Conduct technical review and analysis of risk and cost benefit.
• Quantify subjective factors and analyse aspects with uncertainty.
• Manage closure of the Project as a self‐funded operation and ensure the Project Business Plan includes costs, revenues, profit / loss and cash flows.
• Assess closure costs in terms of economic, technical, and social feasibility.
• Determine that closure does not incur long‐term liabilities to SMC or to the community.
• Comprehensively review costs on a regular pre‐determined basis and taking inflation into account.
• Determine that closure financial provisioning remains flexible to cope with unexpected events, new technologies, operational change or change in community or regulator expectations.
• Determine that cost estimates include management of the project related social and environmental issues.
• Include associated monitoring and long‐term site management costs.
• Determine that closure cost estimates don’t rely on return from sale of assets and salvage value.
• Provision for adequate form and amount of surety and upon closure, determine that requirements for release of surety are met.
• Periodically review assurance levels as closure needs, environmental risks or economic factors dictate.
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Table 8.1 – Closure Cost Estimate
Weld Range Project Approximate Area (ha) Cost per ha ($) Total Cost ($)
Beebyn Pit and Waste Dumps 1098 12000 13,176,000
Madoonga Pit and Waste Dumps 715.5 12000 8,586,000
Madoonga Pit Infrastructure 72.6 5000 363,000
Central Processing Facility – Plant and Infrastructure
450 10000 4,500,000
Evaporation Pond 674 12000 8,088,000
Accommodation Village 161.3 5000 806,500
Airstrip 55 5000 275,000
Access Tracks and Haul Roads 549 5000 2,745,000
ANFO 40.3 10000 403,000
Borrow 258.4 10000 2,584,000
TOTAL 4074 (40.7 km2)
TOTAL COST 41,526,500
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8.2 CLOSURE SCHEDULE
SMC closure schedule is detailed below in Table 8.2.
Table 8.2 Mine Closure Schedule
Project Stage Activity Cost Estimate Basis Reliability
Pre‐Feasibility
Discussions with stakeholders on project impacts.
Conceptual closure planning.
Costing broad and determined through experience.
Variable
Prior to construction
Conceptual closure planning.
Discussions with stakeholders on end land use.
Environmental bonds.
Variable
Construction Progressive rehabilitation. Preliminary. +/‐ 25%
Operations Progressive rehabilitation. Budgetary. +/‐ 25%
2 years prior to decommissioning
Detailed engineering planning of closure.
Quoted costing of major elements of closure.
Progressive rehabilitation.
Controlled. +/‐ 15%
Annually prior to decommissioning.
Progressive decommissioning of project components no longer required.
Progressive rehabilitation.
Reviewed and updated.
+/‐ 15%
8.3 ACCOUNTING STANDARDS
SMC will establish a closure provision in accordance with the requirements of Australian Accounting Standards Board 137 ‐ Provisions, Contingent Liabilities and Contingent Assets.
This accounting provision is a full liability provision and an amount of money has been set aside to cover all final rehabilitation costs. This amount shall be reviewed regularly to ensure that enough resources are available for closure.
8.4 ADEQUATE SECURITIES
Unconditional Performance Bonds are lodged with the Department of Industry and Resources in accordance with the Mining Act 1978. The bond is a contract between the Minister for State Development and a bank or third party of financial standing acceptable to the Minister. The bank or third party providing the bond remains liable to the Minister even when the tenement owner is in bankruptcy or liquidation.
The bond may be reduced throughout the life of the Project where rehabilitation has been carried out and has clearly demonstrated stability under at least average seasonal conditions. The bond will be retired when the rehabilitation has met all completion criteria and standards set out in approval documents, annual environmental reports and decommissioning plans, and when the Department of Industry and Resources is satisfied
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that the rehabilitated area is safe, stable, erosion is comparable to the surrounding areas and the biological system is sustainable under a range of seasonal conditions representative of that climate (Department of Industry and Resources, 2009)
Details of SMCs Unconditional Performance Bonds held for tenements held by SMC are detailed in Table 8.3.
Table 8.3 – Unconditional Performance Bonds for SMC Tenements
Tenement Number
Bond Amount Date Last Increase was
Requested Brief description of infrastructure covered
by bond
P51/2581 NA
E20/595 NA
P51/2552 NA
M20/419 NA
E20/457 NA
E20/459 NA
E20/492 $10,000 03/05/2010 Drilling pads and tracks
E51/907 $117,000 26/06/2009 Drilling pads and tracks
M20/402 $28,000 28/05/2009 Exploration camp, firebreak, camp ext.
M20/403 NA
TR70/3902 NA
E20/635 NA
E20/633 NA
E20/641 $19,000 03/05/2010 Drilling pads and tracks
E51/1354 NA
E20/625 $20,000 06/2006 Drilling pads and tracks
P20/2077 NA
P20/2078 NA
P20/2016 NA
P20/2084 $40,000 11/2009 Drilling pads and tracks
P20/2085 $10,000 11/2009 Drilling pads and tracks
M20/503 NA
M20/311 NA
Total $ 244,000
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8.5 REVIEW
This cost estimate will be reviewed annually during operations to adjust for inflation and re‐assessment to account for changing standards and expectations.
The financial provisioning will be reviewed following any alteration to the cost‐estimate to ensure it is appropriate to adequately cover the costs of rehabilitation and decommissioning.
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9 GENERAL REHABILITATION AND CLOSURE STRATEGIES
9.1 WASTE LANDFORM
SMC will undertake appropriate consultation throughout the planning stage of the Project concerning final landforms and all Project work areas.
With the size and scale of operations, the Project will have a significant impact on the surrounding areas. Changing the existing landform with the mining of the pit void and construction of the mine waste dumps will be the most significant visual impact of the mining operation.
The potential impacts of the Project on the geology and landform resources would be associated with the following:
• Permanent landform modification as a result of mine pits.
• Permanent new landforms as a result of the TSF and waste dump areas.
• Short to medium term changes to the landscape as a result of construction of infrastructure.
The Project area is surrounded by flat plains and will cover an area approximately 4074 ha. The proposed pit areas and external waste dumps (at Beebyn and Madoonga) will have a footprint of 1098 ha and 715.5 ha, a height of 600 m RL and 560 m RL and 20° slopes respectively.
On completion of mining, approximately 100 m3 of the mine deposit will be left open. It is anticipated this void will fill up with water to form pit lakes.
9.1.1 Closure Objectives
The objectives for management of final landforms are to:
• Maintain and protect any significant landscape, indigenous heritage and geo‐heritage values and maintain the integrity, ecological functions and environment values of the soil, drainage lines and landforms.
• Meet post‐mining land use requirements.
9.1.2 Completion Criteria
The following are the desired outcomes concerning the development of landforms:
• Project landforms have been shaped and rehabilitated as per stakeholder consultation and condition requirements.
• All Project infrastructure has been removed and rehabilitation of the site to final land use requirements has been completed.
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C1: Final landforms will be developed such that they will remain structurally and chemically stable, safe to humans and provide a sustainable habitat for flora and fauna without ongoing maintenance.
C2: Landforms will conform to the requirements of agreed post‐closure land use.
C3: Access to pit lakes will be prohibited to ensure pit lakes are safe to humans and to minimise the occurrence of fauna mortality.
9.1.3 Management Actions
SMC will undertake public consultation throughout the planning stage of the Project concerning final landforms and all Project work areas.
To ensure the development of safe and environmentally appropriate landforms and to minimise long term visual impacts resulting from the Project, SMC will:
• Establish completion criteria, including landform design, for each landform.
• SMC will conduct research in order to determine what angle of slope would be suitable, based on the type of material in the waste dump. The most stable, lowest erosion potential and natural looking landform will be created. Berms will be removed or made less steep and will slope outwards to prevent water pooling on the face of the dump which could lead to erosion including tunnel erosion and gully formation.
• A crestal bund shall be installed around the top of the dump and incorporated into the slope. This bund has the purpose of retaining water from rainfall on top of the dump to prevent further runoff down the face of the dump and therefore reducing the potential for erosion.
• Topsoil will be spread and then ripped to bring up some rock from the layer immediately under the topsoil. This will help to prevent erosion by “rock armouring” the face of the dump. Lose dead vegetation, tree branches etc, will then be spread over this surface to further enhance erosion control by preventing rainfall runoff from concentrating in one area, slowing the flow of runoff down the face of the dump and promoting the dispersion of runoff across the whole face.
• Implement rehabilitation methods, as described in Section 9.7.3, to achieve the required landform.
• Revegetate the site to the required land‐use objective.
• The end land use for the area will be determined in consultation with stakeholders and agreed with the administering authority. during the life of the mine;
• Sloped landforms will be covered with topsoil and then deep ripped to a minimum of 1 m on contour;
• Ensure rip lines are horizontal for the entire length.
• Monitor the site to determine that agreed outcomes are being achieved.
• Undertake remedial actions as necessary to remedy any deviations from the required objective.
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• Record all actions at the site.
• Leave residual pit voids as run‐of‐mine (ROM) where geotechnically stable, and profile as necessary to achieve long term closure objectives.
• Restrict access to the TSF once mining and processing ceases. Access restrictions will remain until the tailings have consolidated and dried sufficiently to support machinery and allow rehabilitation to be completed. Rehabilitation will be undertaken to ensure that the TSF is safe and stable and potential erosion is minimised.
• Ensure revegetation efforts will be aimed at establishing local native vegetation suitable to domain characteristics.
A major cause of erosion on newly created landforms is the lack of adequate drainage control. Therefore design and construction of drainage control measures will take into account the predicted 1 in 100 ARI flood events.
Reshaping of landforms aims to produce slopes with angles, lengths and shapes compatible with the surrounding landscape, suitable for the proposed land use and not prone to an unacceptable rate of erosion. On finalisation of the Project, the following landforms will require earth works reshaping:
• waste rock dumps;
• ROM pads, borrow pits; and
• haul roads.
Specific closure strategies for key infrastructure are described in Section 10.
9.2 CONTAMINATED SITES
Acid forming waste rock and hazardous materials such as fuels, process reagents, lubricants, detergents, explosives, solvents and paints can be detrimental to plant growth and may result in contamination of both surface and groundwater.
If these materials are not properly managed, they may have the potential to cause atmospheric, soil or water contamination and could potentially pose ongoing risks to human health and the environment.
Under the Contaminated Sites Act 2003 a site is considered to be contaminated if it has a substance present at above background concentrations that presents, or has the potential to present, a risk of harm to human health, the environment or any environmental value.
There are no recognised contaminated sites within the project footprint.
Waste rock has been assessed as predominately non acid forming (NAF) with approximately 11% of the Madoonga and 1% of Beebyn waste material expected to be potentially acid forming (PAF).
The potential exists for contamination to occur during the life of the Project due to the handling and storage of hydrocarbons and chemicals. This potential will be minimised by ensuring hazardous materials are stored in appropriately bunded areas and any spills are cleaned up promptly and appropriately.
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Potential contamination sources may include workshops and plant and fuel storage facilities. Potential impacts relevant to closure include:
• Contamination of soil, groundwater and surface water sources within the Weld Range are as a result of inappropriate storage or handling of chemicals and hydrocarbon.
• Contamination of soil, groundwater and surface water within the Weld Range area as a result of inappropriate management of PAF materials and potential leachate.
• Contamination of groundwater from leachate from pit lakes.
9.2.1 Objectives
There are no existing contaminated sites within the Project footprint. Closure objectives include:
• Ensure no contaminated sites occur through Project operations.
• Ensure any contamination that occurs is investigated and remediated as soon as possible.
• Any significant spills will be reported to the DEC and recorded through SMC’s incident reporting system.
9.2.2 Completion Criteria
The following completion criteria for contaminated locations will be observed before or during closure:
• All known contaminated sites have been investigated and remediated to acceptable levels.
• Specific criteria will be determined for each specific contamination situation.
C4: Contamination of groundwater, surface water and surrounding environment from the inappropriate storage or handling of chemicals and hydrocarbons will be prevented.
C5: Known contaminated sites are remediated to agreed levels as soon as possible.
9.2.3 Management Actions
To reduce the risk of soil or water contamination and to ensure that the site is remediated to agreed standards, SMC will:
• Regularly inspect areas where contamination is likely to occur.
• Develop criteria to be met by remediation and a timeframe for remediation activities.
• Determine appropriate remediation methods and implemented remediation actions.
• Undertake monitoring and/or testing using appropriate, recognised methods, to demonstrate reduction of any contamination to acceptable levels using an independent auditor.
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• Keep appropriate records of all actions and results.
9.3 SURFACE WATER
Surface water drainage lines flowing off the Weld Range will be affected by the development of infrastructure and waste dumps, which may in turn impact the nearby Beebyn and Madoonga creeks. Some vegetation units occur on these drainage lines and are likely to be influenced by changes in surface water flow.
Permanent changes to the pattern of flows due to post closure landforms are likely to result in geomorphic changes to drainage lines around and downstream of the mine site. The degree of change will depend on how post closure flows are distributed compared to the natural distribution of flows. SMC’s aim is to ensure post closure flows are as close as possible to natural conditions.
Potential impacts relevant to closure include:
• Drainage stability and erosion of mine closure landforms.
• Permanent changes to the pattern of overland and sheet flow and the subsequent changes to vegetation distribution.
9.3.1 Objectives
The closure objectives for surface waters are:
• To restore baseline flow regimes, where possible, in areas affected by mining and closure works.
• To maintain baseline surface water quality.
• To ensure stability of permanent diversions, creek reconstructions and other constructed water management works left after mine closure.
• To ensure stability of drainage from landforms created by mining.
• The integrity, ecological functions and environmental values of wetlands and drainage systems interacting with the proposal are maintained.
• Contaminated waters have been controlled and contained on site to prevent entry into groundwater, natural drainage systems and surrounding vegetation and remediation has been undertaken as necessary.
9.3.2 Completion Criteria
The following are the desired outcomes concerning surface water:
• Water use related infrastructure has been effectively decommissioned, as per agreed post land use intentions, and natural drainage patterns are reinstated as far as possible dependent on site layout and water management scenarios.
• Where practicable, surface water drainage has been reinstated to mimic pre‐mining drainage.
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C6: No change in the long term quantity or quality of surface water, so that existing and potential environmental values, including ecosystem maintenance are protected.
9.3.3 Management Actions
The Beebyn and Madoonga mine site infrastructure will be located outside the estimated 100‐year ARI design flood extents of the main creeks. Flood protection measures will be required to protect the site infrastructure, waste dumps and mine pits from inundation caused by sheet flow and localised flooding of minor waterways.
To ensure the appropriate management of surface water during and post mine closure, SMC will:
• Design diversion drains to divert runoff from undisturbed areas around or through the mining operations where possible, with an allowance for 0.5 m freeboard. Diversion drains around the mine site infrastructure and waste dump drainage will be designed to capture and divert the 10 year ARI design flood event, while mine pit diversions will capture and divert the 100‐year ARI design flood event. Portions of the Madoonga waste dump drainage are located within the 100‐year ARI flood risk area (Figure 9.1). This drainage will require safety bunds constructed down gradient of the drains and at a level appropriate to maintain a minimum 0.5 m freeboard above floodwaters.
• Design diversion channels with sufficient capacity for a nominated rainfall event, while minimising earthworks and the channel footprint.
• Ensure channels are the appropriate width and depth and have bed gradient and side batters to minimise channel velocities and ensure a stable channel profile.
• Ensure all waste rock stockpiles are bunded appropriately to contain internal surface water runoff for treatment and to divert external surface water. A crestal bund shall be installed around the top of the dump and incorporated into the slope. This bund has the purpose of retaining water from rainfall on top of the dump to prevent further runoff down the face of the dump and therefore reduces the potential for erosion.
• Develop and implement a monitoring program for surface water level and quality.
• Implement systems and practices to avoid pollution events during the operational life of the mine.
• Manage all pollution events immediately to reduce impact on surface and ground water.
• Rehabilitate all disturbed areas relevant to the project to reduce erosion and facilitate integration into the natural drainage system.
• Record all actions and results.
560
550
540530
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600 610
620 630640
500
620580
620
510
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530510
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490
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500
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510
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MSP01
MSP02
MDD06
MDD07
MD
D05
MDD03
MDD04
MD
D08
MDD02 MDD01M
DD
10
MD
D11
557000
557000
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560000
560000 561000
561000
7017000
7017000
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7019000
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7020000
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DRG NO
TITLE
CHKDRN
CLIENT
DATE
WELD RANGE IRON ORE PROJECTMADOONGA MINE PIT ANDWASTE DUMP DRAINAGE
DG 28-11-20080
REV
13292 FIGURE 9.1SA
REV REVISION DESCRIPTION
LOCALITY
A FOR INFORMATION ONLY
±
0 400 800 1,200 1,600
Meters
Legend
Diversions
Flood Plain
Sump Pump Sediment Ponds (Not to Scale)
Waste Dump Sediment Ponds (Not to Scale)
Mine Pit Stage 1
Mine Pit Stage 2
Mine Pit Stage 3
Waste Dump
INFORMATION ONLYNOT TO BE USED
FOR CONSTRUCTION
Pro
duce
d by
Dar
ryl G
illgr
en G
eom
atic
s W
orle
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sons
WA
NOTES
WORLEYPARSONS PROJECT
DATUM
SCALE @ A31:12,000GCS GDA 1994 MGA z50S
Project Location: G:\150-13923_Weld_Range\GIS
B FOR CUSTOMER REVIEW
FOR USE0
DG
DG
SA
SA
3-12-2008
5-12-2008
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9.4 GROUNDWATER
The Project will have minimal impact on groundwater quality through spillages of liquid chemicals and hydrocarbons and the disposal of various forms of solid and liquid wastes.
Drilling at Weld Range has suggested that:
• Groundwater moves from the north towards the south‐east following the tertiary palaeochannels drainage direction.
• The regional water elevations range between 510.15 m RL (Outcamp Well) along the northern margin to about 427.15 m RL (7 Mile Well) along the southern margin of the investigated area, these wells are 45 km apart.
• The elevation of the water level mound ranges from 482.24 to 507.78 m RL.
• The groundwater is fresh (TDS < 500 mg/l) to marginal (500 < TDS < 1,500 mg/l), except in the boreholes or wells located on the palaeochannels. The areas of higher groundwater salinity correspond to lower topographic areas and surface drainage systems. Owing to the high evaporation rate; the water evaporates as soon as it reaches the surface or even in the vadose zone just below the surface. This results in the deposition of numerous minerals and salts in and around the lower topography areas and subsequently increases the salinity of the immediate groundwater. The water quality then becomes brackish (1,500<TDS<5,000 mg/l) varying from 2,643 mg/l (7 Mile Well) to 4,900 mg/l (Gap Bore) to saline with the highest salinity measured at MDWB01 (48,000 mg/l), M_WBG_01R (46,000 mg/l) and M‐LTM‐04 (35,000 mg/l). The boreholes that have the highest salinity reflect the proximity of these boreholes to the tertiary palaeochannel (SRK 2010a).
• The average regional groundwater is mildly acidic (pH of 5.4) to mildly alkaline (pH of 8.5), indicated from the contouring of the groundwater pH data.
Potential impacts to groundwater arising from the Project and relevant to closure include:
• Lasting disruption to the natural groundwater flow processes as a result of mining operations.
• Pollution from chemical and hydrocarbon materials and waste water streams from the operation.
• Degradation and contamination of groundwater sources from inappropriately constructed and managed TSF and waste rock stockpiles.
• Lasting ecological impacts from the drawdown resulting from pit dewatering.
Following cessation of dewatering, natural recharge and inflow processes will result in water levels recovering to pre‐mining levels. Consequently, there are unlikely to be any significant long‐term impacts on water quality or groundwater flow as a result of this Project. Numerical groundwater modelling will be undertaken to simulate the closure strategy and confirm the viability of the preferred closure option.
Modelling completed in the PER predicts that in the first year post‐mining pit lakes will develop in both Beebyn and Madoonga, as inflow enters into the pits. The water level in the pit lakes of Beebyn will rise up to 480 m RL while in Madoonga the pit water level will reach 430 m RL after 25 years post mining.
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The concentration of solutes within the pit lakes will increase over time due to high evaporation and low precipitation in the area. However these lakes will act as sinks as they will be below the water table level. Therefore no impact to surrounding groundwater will be expected.
9.4.1 Objectives
The closure objectives for groundwater are:
• The quality and quantity of groundwater is maintained, so that existing and potential environmental values, including ecosystem maintenance are protected.
• Hydraulic continuity along the aquifer system will be reinstated post closure.
9.4.2 Completion Criteria
The following are the desired outcomes concerning groundwater:
• Contaminated waters have been controlled and contained on site to prevent entry into groundwater and remediation has occurred.
• Groundwater levels, quality and flow processes return to pre‐mining conditions.
C7: The quality and quantity of ground water is maintained, so that existing and potential environmental values, including ecosystem maintenance are protected.
9.4.3 Management Actions
To ensure the appropriate management of groundwater during and post mine closure, SMC will:
• Prevent groundwater pollution and contamination through appropriate waste management practices, as outlined in the Project Environmental Management Plan.
• Develop and implement a monitoring program for groundwater level and quality.
9.5 DECOMMISSIONING
During the decommissioning phase of the Project, all infrastructure that cannot be used by another party will be removed or buried and the disturbed areas rehabilitated.
Decommissioning will comprise the safe dismantling and removal of infrastructure, the appropriate disposal of waste materials and the return of impacted areas to a variety of vegetation types and fauna habitats that simulate the pre‐disturbance state as closely as possible (or in accordance with agreed post‐mining land use).
This may include the removal of:
• crushing and screening plant and processing buildings;
• fuel and bulk storage facilities;
• workshops;
• dewatering equipment and surplus water disposal equipment;
• offices and accommodation village; and
• support infrastructure including road train and train loading facilities.
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Where the removal of non‐visible infrastructure, or features that have been incorporated into the natural landscape may cause more environmental damage than if left in situ, their retention will be discussed with the relevant authorities at the time.
9.5.1 Objectives
The objectives of decommissioning are to:
• Remove or appropriately dispose of project infrastructure that is not required for post closure land uses.
• Modify, as required, any infrastructure that will remain to ensure its long term safety and viability.
• Dispose of all waste material appropriately and in accordance to agreed outcomes.
9.5.2 Completion Criteria
The following are the desired outcomes concerning Project decommissioning:
• Appropriate removal and/or modification of all required infrastructure.
• Stable long term structural integrity is achieved.
• Public and environmental health and safety is protect.;
• Local ground and surface water characteristics are preserved.
• Successful rehabilitation occurs to support sustainable habitat for native fauna and flora.
• Consideration of post closure land uses is undertaken.
C8: All project infrastructure that is not required for post closure land use will be removed or disposed of appropriately.
9.5.3 Management Actions
To ensure appropriate decommissioning of Project infrastructure, SMC will:
• Identify what infrastructure will remain and what will be removed in consultation with stakeholders.
• Ensure that any Project infrastructure that will not be used by a post closure land user is removed.
• Rehabilitate disturbed areas to suit post closure land uses and to reflect the pre‐disturbance condition.
Following the removal of infrastructure and re‐profiling of the land surface, additional surface treatment works will be implemented including:
• Rehabilitation management actions as outlined in Section 9.7.3.
• Maintenance of sediment traps where required (e.g. recently rehabilitated areas) to reduce the potential for the migration of sediments.
• Undertake contamination remediation and rehabilitate all sites to the agreed completion criteria.
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• At the completion of mining, haul roads that have not been rehabilitated as part of the progressive rehabilitation programme will be re‐profiled (including removal of portions of haul road embankment where necessary) to blend in with surrounding topography. Where necessary, road surfaces will be re‐profiled to allow free drainage and minimise interference with surface flows.
9.6 VISUAL AMENITY AND HERITAGE
Due to the isolated nature of the project location it is not anticipated that the Project will have a significant impact on visual amenity of locals or tourists.
However the mine will result in highly visible, permanent changes to the landscape and SMC are committed to reducing these visual impacts and maintaining post closure the amenity and original uses of the area.
9.6.1 Objectives
• Ensure that aesthetic values and public experience of the landscape are considered, and measures are adopted to reduce the visual impacts on the landscape.
• Protect, as far as possible, the heritage values of the area.
9.6.2 Completion Criteria
The following are the desired outcomes concerning aesthetics and indigenous heritage:
• Aboriginal heritage sites have not been disturbed without approval from the Department of Indigenous Affairs (DIA) and the areas traditional custodians.
• All sites have been signed off by stakeholders and responsible authorities.
C9: Ensure that aesthetic values and public interaction with the landscape are considered, and measures are adopted to reduce the visual impacts on the landscape.
C10: Maintain and protect any significant landscape, indigenous heritage and geo‐heritage values.
9.6.3 Management Actions
To ensure that amenity values of the area are maintained, SMC will:
• Consult with relevant stakeholders throughout the life of the project to determine appropriate end land use.
• Mining landforms will be rehabilitated consistent with landscape values of the area and sympathetic to natural mesa.
• Use of concave slopes to assist the engineered structures to appear more natural and offer more resistance to erosion than linear slopes.
• Use of endemic plant species to ensure that rehabilitation is sustainable and comparable to the surrounding environment.
• Placement of additional waste rock material on the top surface of the structures to break up the uniformity of the flat surface and contouring of the top surface to prevent water
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overtopping the embankments and causing excessive erosion. A store and release cover system will be employed to provide suitable habitat for reseeding with endemic species.
• Progressive rehabilitation of all areas, removal of stream diversion drains and ponds, re‐contouring of the landscape and revegetation with endemic species.
• The surrounding landscape will be considered when deciding on the location, design and colour of mine infrastructure.
• Following completion of mining operations and processing, remaining infrastructure that does not have any post‐mine benefit will be demolished, removed and the area rehabilitated.
9.7 REHABILITATION OF NATIVE VEGETATION AND TOPSOIL
Minimising or controlling the disturbance footprint of the Project is the most effective method for ensuring that closure objectives with respect to a functioning ecosystem are met. Vegetation disturbance refers to the direct impact of clearing as well as indirect disturbance through the spread of weeds, fire, altered hydrology, soil or water contamination and dust.
Rehabilitation is the process used to repair the impacts of mining on the environment. The long‐term objectives of rehabilitation can vary from simply converting an area to a safe and stable condition, to restoring the pre‐mining conditions as closely as possible to support the future sustainability of the site (DoIR, 2006b).
Rehabilitation normally comprises the following:
• Developing designs for appropriate landforms for the mine site.
• Creating landforms that will behave and evolve in a predictable manner, according to the design principles established.
• Establishing appropriate sustainable ecosystems.
9.7.1 Objectives
The closure objectives for rehabilitation are:
• Minimise the loss of native vegetation and plant communities.
• Protect Priority flora within the Project area.
• Protection of Idiosoma and Cethegus.
• Ensure that rehabilitation achieves a safe, stable and functioning ecosystem that meets the requirements of the post‐mining land use.
• Undertake progressive rehabilitation to minimize open areas as far as possible and reduce the likelihood of weed infestation.
• Weed outbreaks as a result of project activities have been assessed and controlled in a manner agreed with stakeholders and responsible authorities.
• Rehabilitation measures and methods utilised comply with agreed and approved rehabilitation management guidelines.
• Practices fulfil commitments made to stakeholders and regulators regarding closure outcomes.
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9.7.2 Completion Criteria
The following are the desired outcomes concerning the rehabilitation of native vegetation:
• SMC will comply with and ANZMEC‐MCA Strategic Framework for Mine Closure (2000), to return the mine site, where practicable, to a viable self‐sustaining ecosystem that is adequately financed, implemented and monitored within all jurisdictions.
• Overburden stockpiles and disturbed sites have been constructed according to the approved design criteria.
• Rehabilitation has occurred progressively where possible and areas have been revegetated to meet the agreed post‐mining land uses.
C11: Impacted areas are returned to self‐sustaining vegetation communities and fauna habitats that reflect pre‐disturbed state.
C12: Weed species cover is identified and contained to minimise spread into weed free areas.
C13: Topsoil remains viable and has the capacity to support a safe, stable and functioning ecosystem that meets the requirements of the post‐mining land use, where it exists
9.7.3 Management Actions
To ensure the Project site is adequately rehabilitated during mine operation and post mine closure, SMC will:
• Control clearing in accordance with the Project EMP.
• Management of Idiosoma nigrum as outlined in the Conservation Management Plan.
• Management of Cethegus sp. as outlined in the Conservation Management Plan.
• Management of feral animals as outlined in the Project EMP.
• Rehabilitation will be carried out progressively over the life of the Project.
• Rip on contours to relieve compaction, reduce erosion and improve water infiltration. Deep ripping will be undertaken where the soil or waste material is of low permeability. In areas where the soil or waste material is of high permeability scarifying on contours will be undertaken. On steep slopes this may require terracing or benching. All ripping, terracing or benching will be surveyed to ensure that they are on contours.
• Re‐establish stable landforms with erosion control measures for long term stability will be undertaken.
• Where available, utilise topsoil to provide a foundation into which native vegetation will be planted and/or seeded. Topsoil or other suitable material will be applied at an appropriate depth, in the order of 100 mm where practicable, to achieve revegetation.
• Ensure direct seeding and/or planting is undertaken to encourage vegetation growth to stabilise surfaces and aid the integration of landforms into the surrounding landscape and ecosystems. Seeding and/or planting will be undertaken prior to the wet season (as soon as possible after earthworks) using seed and plants native to the Project area.
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• Topsoil will be spread and then ripped to bring up some rock from the layer immediately under the topsoil. This will help to prevent erosion by “rock armouring” the face of the dump. Loose dead vegetation, tree branches etc, will then be spread over this surface to further enhance erosion control by preventing rainfall runoff from concentrating in one area, slowing the flow of runoff down the face of the dump and promoting the dispersion of runoff across the whole face.
• Local provenance seeds will be collected from the impacted project area prior to disturbance. Local provenance seeds will be stored separately and used in their respective local areas during rehabilitation.
• Reporting procedures will be established to ensure that results of all trials and actions are properly recorded, referenced, and available for other personnel and for long‐term reference.
• Rehabilitation monitoring will be carried out until revegetation meets the designated completion criteria and is signed off by the DMP. In response to monitoring results, infill planting and weed control will be implemented as necessary.
• Visual inspection of rehabilitated areas will be carried out following rain to ensure that any potential erosion issues are identified early and can be repaired before they become severe.
• Photographic monitoring will be undertaken. This will consist of establishing fixed photographic points (adequately marked with a long lasting item such as metal star picket) and taking photographs from each of these points.
• Quantitative assessment of the progress of revegetation will be undertaken. Replicate monitoring quadrats (20 m x 20 m) will be established and total plant species richness and plant cover index will be recorded.
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10 SPECIFIC CLOSURE STRATEGIES
Where specific closure strategies are required, closure objectives, strategies and completion criteria have been developed to deal with these aspects. These project components are listed in the following section and they will be decommissioned and rehabilitated in accordance with Section 9 of this document.
10.1 BEEBYN AND MADOONGA PIT CLOSURE
Beebyn and Madoonga will be developed as conventional open cut mines. The proposed operations at Weld Range are expected to have a disturbance footprint of about 4074 ha (40.7 km²), or 18% of the total area occupied by the Weld Range (approximately 22,500 ha (225 km2).
The proposed pits and waste dumps will have a total footprint of 1811.5 ha and a strike length of 6 km. The pits will have an anticipated combined production rate of 15 Mtpa, over an initial 11 years. The two deposits are some 22 km apart, with ore from Madoonga and Beebyn planned to be primary crushed and hauled via road train to the CPF. Both deposits will be mined in parallel to enable blending the higher Beebyn iron (Fe) grades with the lower Madoonga Fe grades as well as allowing more control of contaminant grades.
The Beebyn and Madoonga deposits differ in several respects. Madoonga, the western ore body, is the larger of the two deposits but has the lower Fe grade. The deposit contains a broadly continuous BIF horizon, which strikes ENE and dips steeply (>70°). The iron mineralisation is complex and contains semi‐continuous ore lenses separated by thin units of ‘waste’ material. In some cases the ore lenses contain units of internal ‘waste’ material.
The Beebyn deposit is the lower tonnage and higher Fe grade of the two deposits. This deposit contains three definable BIF units that are disrupted by N‐S striking sub‐vertical faults. The BIF units are ENE‐striking and dip steeply (>70°) to the SSE.
Both ore bodies are long (≥3 km) and relatively narrow (5 ‐30 m). The deposits are steeply dipping (almost vertical) and, as a result of the presence of contaminants, do not lend themselves easily to bulk mining.
At year 11, on completion of mining, approximately 100 Mm3 of the mine deposit will be left open. It is anticipated this void will fill up with water to form pit lakes.
The water level in the pit lakes of Beebyn will rise up to 480 m RL while in Madoonga the pit water level will reach 430 m RL after 25 years post mining. The simulation indicates a rapid recovery of the water table in the first five years, followed by a slow down of the recovery with time.
The concentration of solutes within the pit lakes will increase over time due to high evaporation and low precipitation in the area.
SMC will commit to management of open pits, and pit lakes, in accordance with the Department of Industry and Resources Environmental Notes on Mining (Sept 2009) ‐ Care of Maintenance. In which open pits will be managed with appropriate bunding and surface water drainage structures.
In order to minimise inadvertent public and fauna access to the pit lakes SMC will construct a surface water drainage trench and abandonment bund surrounding the pits (Figure10.1). The diversion trench will be no deeper than 2 m with a gentle slope away from the pit and a steeper slope on the
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pit slide. This design will ensure animals leave the trench area away from the pit. The abandonment bund will be approximately 2 m high.
Pit Lakes
SMC will commit to the following management strategies in relation to pit lakes:
• Consideration of the backfilling of mined out areas.
• Management of the water quality within the pit lakes.
• Management of potential leaching from the pit shell, including monitoring bores.
SMC will commit to the management of open pits and pit lakes, in accordance with the Department of Industry and Resources Environmental Notes on Mining (Sept 2009) ‐ Care of Maintenance. In which open pits will be managed with appropriate bunding and surface water drainage structures, Figure 10.1.
The consideration of backfilling pits has been considered; while the results from modelling demonstrate that backfilling concurrently with mining is feasible, however only limited quantities of waste are able to be stowed in‐pit, with the major proportion of the waste being stored in external waste dumps.
Monitoring of the groundwater aquifer surrounding the pit will be monitored under the following periods as detailed in Table 10.1. Parameters measured will include salinity, pH and leachate of contaminates. Monitoring will cease when two consecutive results indicate a stable and acceptable environment similar to that identified prior to the commencement of mining operations as defined in the Ground Water Operating Strategy.
Table 10.1 – Monitoring for sailinty, pH and leaching of contaminates for pit lakes
Monitoring Timescale Period post closure
Yearly Closure (0 years) to 4 years
Every 5 years Year 5 to 25 years
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Figure 10.1 – Indicative Cross Section of Surfacewater Diversion Trench and Abandument Bund
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10.2 WASTE ROCK DUMPS
There are no pre‐existing overburden stockpiles at the Project. Five waste rock dumps will be developed (Figure 10.2), three at the Beebyn pit and two at the Madoonga pit.
The Project is expected to produce at least 273 Mt of waste rock from Madoonga pit and at least 450 Mt from the Beebyn pit. A small proportion of this waste rock will be PAF, with estimated tonnages of PAF material of 30 Mt at Madoonga (11%) and 4.5 Mt at Beebyn (1%).
The parameters used for the waste dump design for both the Beebyn and Madoonga areas are listed below and illustrated in Figure 10.2:
Berm width 10 m Bench height 10 m
Overall slope 20 ° Batter slope 30 °
Swell 0 % Tolerance 10 %
Road width (dual‐lane) 30 m
The size of the waste dumps has been estimated from assumed swell factors applied to the in situ volume mined. Haulage distances from the open pit designs and the dump designs will be minimised by locating the pit ramps of the pit designs appropriately.
Beebyn currently has three planned waste dumps. These include a large dump servicing the Beebyn pit which has been configured so that the dump ramps are aligned with the south wall pit ramps to provide short waste haulage. Smaller waste dumps are planned to service the Beebyn pit. The Beebyn pit waste dumping area is to the south of the pit area to minimise interaction with infrastructure such as the crushing and screening processes and the rail loop located to the north of the Beebyn pit. The Beebyn West waste dump is located to the north of the pit. This has been designed large enough to accommodate the waste from the eastern pod. A separate ramp which aligns with the pod’s exit is also allocated to minimise the haul distance. As the dump location is away from the main Beebyn infrastructure, the location of the waste dump is less critical.
Madoonga’s waste dump area is planned at the north side of the pit to avoid environmental issues related to protected fauna located in the valley to the south of the pit. The Madoonga waste dump is designed to provide a large storage capacity in the vicinity of the Stage 1 pit area as this cut‐back produces the largest amount of waste.
Placement Criteria
The following environmental criteria were considered in the planning of overburden stockpile locations:
• Alignment with natural topographic landforms in the area.
• Use of existing previously disturbed agricultural areas.
• Limiting of interference with natural drainage lines.
• Avoidance of sensitive flora and/or fauna habitat.
• Avoidance of indigenous heritage sites.
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10.2.1 Closure Objectives
The closure objectives are to ensure:
• Rehabilitation achieves a safe, stable, non‐polluting landform consistent with the surrounding landscape.
• Revegetation is consistent with the surrounding flora and land use, or other land use as agreed.
• There is a sufficient cover of vegetation established to minimise erosion and to fulfil agreed rehabilitation commitments.
• The final landform conforms to design criteria and is resistant to erosive events.
• To limit contact between PAF and percolating water.
• To minimise the likelihood that dump effluents will exert a detrimental effect on local water quality, for example, by capturing and managing dump drainage appropriately, and if practicable, locating the PAF material away from existing water courses ands flood areas.
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Figure 10.2 – Cross Section of the Proposed Waste Dump Design
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10.3 OVERBURDEN STOCKPILES
Overburden stockpiles will require earthworks and subsequent revegetation through seeding or planting to ensure they are stable and blend into the surrounding landscape.
Design
The final form of new overburden stockpiles will conform to the design criteria outlined in the DMP Guideline for Mining in Arid Environment (2007).
Construction will utilise a bottom up methodology incorporating progressive rehabilitation. Outside faces of stockpiles are to be constructed initially and rehabilitated upon completion of each level. The methodologies outlined in Guidelines for Mining in Arid Environments (DoIR, 2007) will be applied to the construction of stockpiles.
PAF
To meet the waste rock objectives the following management strategy has been proposed:
The base layer of the dump (A) will be constructed of NAF material (Figure 10.3). The purpose of this layer will be to raise the PAF material above the original ground and prevent direct contact of PAF material with any water flowing at the interface of the original ground and the dump.
Figure 10.3 – PAF Waste Rock Surrounded by NAF Waste Rock
The minimum thickness of the base layer will be determined based on information such as the saturated and unsaturated hydraulic properties of the base layer, estimates of rates of infiltration into the waste from rainfall, natural seeps and flood levels.
During construction there is the potential for areas of PAF rock to be uncovered and exposed to rain. These exposure times will be minimised as far as possible through scheduling mining or dumping and planning the location of the PAF material in the dump. In order to reduce the load of oxidation products that could be released from PAF material during construction, a layer of low permeability NAF material (B) will be placed over the NAF base layer and under the PAF rock (C). The purpose of layer B will be to limit the rate of downward movement of water and therefore reduce the rate of
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release of any AMD produced. It is likely that a portion of water moving downward through the dump will exit the dump at the base and continue to move downward towards the groundwater table.
PAF material will be covered on both of the side slopes (batters) and top surface with NAF material. A cover (D) designed to limit the infiltration of rain will be constructed on the top surface of the dump. It will extend laterally beyond the PAF material. The final design of the cover will be determined based on the annual rainfall, rainfall intensity distribution and potential evapotranspiration. The design would likely include features to promote runoff from the surface and/or promote retention of infiltrating water near the surface for subsequent evapotranspiration.
Engineering design of the waste dump will incorporate the following:
• appropriate slope angles;
• berms and drains;
• batters resistant to erosion to maintain the NAF layer; and
• cut off drains to prevent runoff from undisturbed lands contacting the dumps and to separate dump run‐off from water running off undisturbed land. Dump run‐off will be channelled to settling ponds to store sediment.
Topsoil
Topsoil will be stripped in advance of the overburden stockpile face and stored. If possible, topsoil will be re‐spread directly on overburden stockpiles. Stripped topsoil and subsoil that cannot be directly re‐spread will be stockpiled separately according to the methodologies outlined in Guidelines for Mining in Arid Environments (DoIR, 2007).
Topsoil stockpiles will be located within the marked overburden stockpile disturbance areas.
The existing environment within the project areas naturally consists of shallow depths of topsoil and subsoil. Overburden stockpiles will be re‐spread with topsoil and subsoil to equivalent depths as those occurring in undisturbed areas. To ensure sufficient volumes of subsoil are available for re‐spread on overburden stockpiles, the following measures will be undertaken:
• Topsoil will be stripped and stored separately at designated topsoil stockpile locations.
• Weathered material retrieved from pit excavations will be stored separately at designated subsoil stockpile locations.
• Topsoil will be stripped in advance of overburden stockpile toes over the anticipated stockpile footprints and stored separately at designated topsoil stockpile locations.
• Subsoil will be stripped in advance of overburden stockpile toes over the anticipated stockpile footprints and stored separately at designated subsoil stockpile locations.
Where the availability of topsoil and subsoil is less than the quantity indicated for specific sections of the Project, SMC will develop other options for sourcing this material, from approved borrow pits, other disturbed areas or from suitable pit overburden material.
An assumption with regard to the estimate of subsoil requirement for areas to be rehabilitated is that the surface area needed will be 115% of that of the original area disturbed, due to the convex shape of the final waste dump design.
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Topsoil will be spread over a layer of subsoil. Topsoil will be spread preferentially over the overburden stockpile top level and benches where vegetation establishment is more likely.
Erosion Control
The overburden stockpiles will be designed to encourage infiltration and drainage of surface water, minimising surface flow. The final slope profile of the stockpiles will conform to the following design criteria:
• Overburden stockpile toe does not extend into the area surrounding the pit where collapse is possible.
• Bank slopes are restricted to a maximum angle of 20°.
• Berms are placed every 10 m of vertical height.
• Berms are sloped into the stockpile at 5° angle.
• Berms have cross bunds every 30 m of length to reduce water flow along the berm.
• Peak of overburden stockpiles does not exceed the height of surrounding natural land forms.
• A crestal bund shall be installed around the top of the dump and incorporated into the slope. This bund has the purpose of retaining water from rainfall on top of the dump to prevent further runoff down the face of the dump and therefore reduces the potential for erosion.
Revegetation
Seeding programs will be conducted prior to the wet season (May – August) on overburden stockpile surfaces that have been respread with top/subsoil. Provenance seed collection is to occur during the flowering season (generally after spring) one year prior to planned rehabilitation.
Where possible any cleared vegetation and litter will be stockpiled for respreading on areas to be rehabilitated.
Flora species will be chosen for rehabilitation based on vegetation communities identified in botanical surveys conducted over the project area. Principles of succession will be incorporated into species selection, and rehabilitation will also include efforts to re‐establish Priority Flora taxa. Discussions with the DEC will be carried out to ensure that appropriate seed mixes are used over the areas to be rehabilitated. Those taxa that can be propagated easily would also be suitable to be replanted as tube stock and could be propagated in advance.
Revegetation targets will be set at a density, complexity and diversity of baseline data to replicate surrounding vegetation, in consultation with DEC. Completion criteria will be developed in consultation with DEC to determine when the rehabilitation can be considered self sustaining.
10.3.1 Completion Criteria
• Overburden stockpiles conform to design criteria.
• Stockpiles meet stability, soil and vegetation criteria as determined through consultation with DEC.
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10.4 BORROW PITS AND HAUL ROADS
At the completion of mining at Weld Range, access roads that have not been rehabilitated as part of the progressive rehabilitation programmes will be rehabilitated (including removal of portions of road embankment where necessary) to blend in with surrounding topography. Where necessary road surfaces will be reshaped and ripped to allow free drainage and minimise interference with natural surface flows.
Borrow pits will be progressively rehabilitated during the operational life of the mine, or following closure of the pit. Sides of the borrow pits will be battered to a slope equal to or less than 20°. Where required, culvert diversion drains and upslope windrows will be used to divert surface flow from entering pits and contributing to waterlogging or erosion.
Borrow pits will then be ripped and spread with topsoil as per section 9.7.
10.4.1 Borrow Pits
The closure objectives are to ensure:
• The profile of final borrow pits are safe, stable, blend into the surrounding landscape and are not prone to erosion.
• Borrow pits are contour ripped and spread with topsoil.
• Pits are free draining.
• Vegetation is comparable to immediate surrounds in species composition and cover.
10.4.1.1 Completion Criteria
• Borrow pit slopes are no greater than 20°.
• Contour ripping or scarifying has been conducted.
• Vegetation is comparable to immediate surrounds in species composition and cover.
10.4.2 Haul Roads
It is anticipated that haul roads will be utilised for post‐closure land use. There are several possible outcomes for closure of the haul roads:
• Haul roads remain as a permanent access road for post‐closure land use.
• Haul roads are decommissioned – the rehabilitation procedures outlined in this conceptual closure plan will be followed.
• Haul roads remain with a reduced width; roads will be narrowed with rehabilitation on cleared shoulders conducted in accordance with this conceptual closure plan.
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10.5 DEWATERING BOREFIELDS AND PIPELINES
Following mine closure, all infrastructure associated with the pit dewatering bores (including powerlines, bores and pipeline) will be removed unless otherwise agreed.
The location of water supply infrastructure is yet to be confirmed, but is likely to include:
• pumps & gen‐sets;
• delivery pipelines;
• turkeys‐nest(s);
• storage tanks;
• distribution pipelines; and
• water treatment plant.
The Madoonga and Beebyn pits are to be serviced by individual bore fields with associated storage and distribution infrastructure.
Water for construction purposes will be provided via construction bores supplying a turkeys‐nest and distributed by road tankers.
Water for operational and fire protection purposes will be provided via production bore fields feeding into storage tanks, where it will be distributed via pipelines to the appropriate plant areas.
Rehabilitation works to be undertaken include:
• Collapse or filling of boreholes.
• Concrete footings and slabs associated with pumping equipment will be broken up and placed within areas of general backfill or buried in‐situ to a minimum depth of 1.5 m below the rehabilitated surface.
General surface treatment and rehabilitation works will then be implemented as described in Section 9.7.
10.6 POWER GENERATING AND SUPPLY INFRASTRUCTURE
The power supply to Weld Range is via diesel powered generators with separate power stations proposed at each site (central processing facility, Beebyn mine, Madoonga mine, accommodation village and the airstrip).
The following generation and transmission related structures on the Project will require decommissioning:
• diesel generators and associated plant;
• substations; and
• overhead transmission lines.
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At the conclusion of mining at Weld Range, all power generating and supply infrastructure will be decommissioned and removed from site unless otherwise agreed. This will include the breaking up of concrete footings and slabs for placement within areas of general backfill or burial in‐situ below the rehabilitated surface (to a minimum depth of 1.5 m)
General surface treatment and rehabilitation works will then be implemented as described in Section 9.7
10.7 ACCOMMODATION VILLAGE AND AMENITIES
The Weld Range accommodation village and associated amenities will be decommissioned and removed from site at the completion of mining unless otherwise agreed.
Decommissioning works to be undertaken include:
• Removal of accommodation units. • Removal (i.e. break up) of concrete footings and slabs and placement within the areas of
general backfill or in‐situ burial to a minimum depth of 1.5 m below the rehabilitated surface.
General surface treatment and rehabilitation works will then be implemented as described in Section 9.7.
10.7.1 Sewerage
Sewerage plants will be designed as modular, portable units which will be removed on decommissioning. Liquid output from the sewage plants will be Class A water, while solid output from the plant will be removed by suitably qualified waste contractors.
10.7.2 Access Roads and Aerodrome
At the completion of mining at Weld Range, access roads that have not been rehabilitated as part of the progressive rehabilitation programmes will be re‐profiled (including removal of portions of road embankment where necessary) to blend in with surrounding topography. Where necessary road surfaces will be profiles to allow free drainage and minimise interference with surface flows.
The future of the Weld Range aerodrome following closure of the Weld Range Mine will be determined in consultation with the administering authority and other relevant stakeholders.
General surface treatment and rehabilitation works will then be implemented as described in Section 9.7.
10.7.3 Fuel and Explosives Facilities
Fuel and explosives storage facilities will require decommissioning, these include:
• bulk hydrocarbon storage areas: total of 3 x 1 ML diesel fuel tank(s) stored adjacent to the servicing workshops and managed in accordance with Australian Standard 1940 – The Storage and Handling of Flammable and Combustible Liquids (AS 1940‐1993);
• explosives storage facility;
• minor storage areas: servicing work shops, may contain oil drums and other materials may need to be removed and disposed appropriately; and
• explosives magazines may need to be demobilised.
General surface treatment and rehabilitation works will then be implemented as described in Sections 9.7.
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11 MONITORING AND MAINTENANCE
11.1 MONITORING, REPORTING AND RECORD KEEPING
The implementation of a monitoring programme is crucial in recording the success or otherwise of the mine closure, as well as validating agreed criteria for relinquishment. Monitoring will address the following areas:
• biological (flora, fauna and SRE);
• kinetic testing;
• surface and groundwater;
• remediation of contaminated sites and acid rock drainage issues;
• public safety;
• landform stability; and
• revegetation status.
Post‐closure monitoring programs will be developed in consultation with appropriate regulatory agencies, and will aim to inform the development of agreed actions if it is determined through monitoring that closure completion criteria are not being met. Monitoring will be undertaken by SMC until the completion criteria have been finalised.
Table 11.1 describes the proposed timing of closure monitoring for the Weld Range project.
Table 11.1 – Timing of Closure Monitoring
Aspect Monitoring Criteria Timing
Public Safety
Engineering assessment of stability of final landforms.
Abandonment bunds in place and adequate signage.
Agreed closure plan criteria.
Safety Bund Walls around Abandoned Open Pit Mines (DME, 1997)
On closure
Overburden Stockpiles
Engineering assessment of stability of final landforms and erosion.
Agreed closure plan design criteria.
On closure then every 6 months.
Contamination Contaminated sites assessment. Contaminated Sites Act 2003.
On closure then every 6 months after remediation if required.
Acid Drainage and Mineral Leaching
Assessment of waste rock dumps for acidity and mineral leaching.
National Handbook “Managing acid and metalliferous drainage”
On closure then every yea or until completion criteria met.
Water Ground and surface water assessment
Groundwater – TDS, SWL, component analysis meet
On closure then annually for 3 years or until
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Aspect Monitoring Criteria Timing
requirements.
Surface – TSS, pH, EC meet requirements.
Drainage – diversion drains will remain in tact after closure.
completion criteria is satisfied.
Rehabilitation Earthworks
Confirmation that earth works have been completed at all sites in accordance with specifications
Agreed closure plan design criteria.
12 months
Vegetation
Visual (photographic) assessment of rehabilitated areas. Includes assessment of weed species, vegetation establishment and cover, and erosion.
Agreed closure plan criteria.
18 months (6 months after seeding).
Fauna / SRE Feral Animal monitoring. Agreed closure plan criteria.
Maintenance Implement maintenance procedures if required.
Agreed closure plan maintenance strategies.
12 months.
Annually as required until completion criteria is satisfied.
11.2 MAINTENANCE
Based on monitoring assessments, periodic maintenance may be required to ensure rehabilitation success. Where closure criteria have not been met, remedial action may be required. Table 11.2 identifies project aspects and actions that will be implemented in the event of incomplete or unsuccessful rehabilitation. Regular maintenance and identification of rehabilitation problems at an early stage will contribute to successful environmental outcomes and mine closure.
Figure 11.1 – Maintenance Actions
Aspect Possible Maintenance Action
Contamination and ADML
- Bioremediation.
- Transportation for treatment of contaminated soils.
- Implementation of ADML control measures.
Vegetation - Reseeding of rehabilitation areas.
- Removal/spraying of weeds.
Topsoil viability - Additional ripping/aeration.
- Application of fertilizers.
Introduced Fauna - Repairs to stock fencing.
- Erection of new fencing.
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12 CONTINGENCY PLANNING
In the event of a temporary suspension of mine operations the Mines Safety and Inspection Regulations 1995 will be utilised to guide development of a suspension plan. The Department of Mines and Petroleum (DMP) will be notified of the nature of the suspension and measures in place that will limit impact to the environment and ensure health and safety requirements are met.
The suspension plan will not consist of a full rehabilitation and closure strategy but will incorporate interim measures. In the event that a decision to decommission operations is made during a suspension period, closure strategies outlined in this Conceptual Closure Plan will be implemented in full in consultation with the relevant authorities.
As a minimum the suspension plan will include:
• Maintenance of drainage structures to limit erosion events and sedimentation of surface water.
• Removal of chemicals, hydrocarbons and other hazardous substances. This includes assessment of containment facilities and bunds to ensure contamination is not possible.
• Provision of maintenance staff / caretakers to monitor mine conditions.
• Ensure adequate on‐site facilities for any staff remaining at the operations.
• Revision of reporting procedures and consultation with regulators regarding mine suspension.
• Removal of domestic and industrial waste products, and waste facilities.
• Provision of adequate signage, safety measures and security to ensure no un‐authorized access to the mine site.
12.1 WALKAWAY
In the situation of sudden (unplanned) closure, a decommissioning plan will be immediately prepared and implemented with input from the Conceptual Closure Plan, taking into account the site’s non‐operational status. Where provision accounts are inadequate to fund the full closure requirements, funds will be provided from other company sources. Figure 12.1 illustrates the sudden closure strategy.
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Figure 12.1 – Sudden Closure Strategy
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12.2 TEMPORARY CLOSURE
Mining activity may cease and shut down on a temporary basis, with the assumption that the operation will recommence in the near future. A decommissioning plan will be immediately prepared and implemented with input from the Conceptual Closure Plan, taking into account the potential for future operations. The Conceptual Closure Plan will be reviewed, as it may be required to be implemented if circumstances remain adverse to reopening the operation.
Rehabilitation will be undertaken on all disturbed areas, where possible and economically practicable, and site remediation works will be undertaken to prevent potential off‐site contamination. The site will be placed under care and maintenance until such time as the operation recommences or it is closed indefinitely. Figure 12.2 illustrates a temporary closure strategy.
12.3 RELINQUISHMENT
The unconditional performance bond(s) lodged with the DMP will be retired when the rehabilitation has met all completion criteria and standards set out in approval documents, annual environmental reports and decommissioning plans. Once the rehabilitated area is safe, stable, erosion is comparable to the surrounding areas and the biological system is sustainable under a range of seasonal conditions representative of that climate (DMP, 2008), the management and maintenance of the site will rest with the subsequent owners or the State.
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Figure 12.2 – Temporay Closure Strategy
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13 REVIEW AND REVISION
The Conceptual Closure Plan will be reviewed throughout the life of the project and revised into a full Closure Plan at least two years prior to the planned closure of the Weld Range Project.
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14 REFERENCES
ANZMEC/MCA (2000), Strategic Framework for Mine Closure. Australian and New Zealand Minerals and Energy Council and Minerals Council of Australia. Canberra, ACT
Department of Industry and Resources (2006) Mine Closure and Completion: Leading Practice Sustainable Development Program for the Mining Industry. Commonwealth Government.
Department of Industry and Resources (1997) Safety Bund Walls Around Abandoned Open Pit Mines. Western Australian Government.
Department of Industry and Resources (2006) Mine Rehabilitation: Leading Practice Sustainable Development Program for the Mining Industry. Western Australian Government.
Thorne, A. M., and Tyler, I. M. (1997) Roy Hill (2nd Edition): 1:250,000 Geological Series Explanatory Notes, 22p.
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