mine closure and rehabilitation plan wonarah ...mine closure and rehabilitation plan wonarah...

MINE CLOSURE AND REHABILITATION PLAN

WONARAH PHOSPHATE PROJECT

NOVEMBER 2009

Coffey Natural Systems Pty Ltd ABN 61 005 041 878

Unit 8, 21 Parap Road Parap NT 0820 Australia

T (+61) (8) 8901 1200 F (+61) (8) 8901 1299

coffey.com

MINE CLOSURE AND REHABILITATION PLAN

Wonarah Phosphate Project

November 2009

CR 9014_10_v3

© Coffey Natural Systems Pty Ltd November 2009

Project director Daniel Moriarty, Tara Halliday

Project manager Rebecca Powlett

Version: Details: Approved: Date:

CR 9014_10_v3 Final for exhibition DM 13/11/2009

Mine Closure and Rehabilitation Plan Wonarah Phosphate Project

CONTENTS

1. INTRODUCTION 1 1.1 Premise for Mine Closure and Rehabilitation 1 1.2 Planning for Mine Closure 4 1.3 Objectives of this Plan 5 1.4 Scope and Review of the Plan 5 1.5 Structure of the Plan 5

2. CLOSURE REQUIREMENTS 7 2.1 Legislative Requirements 7

2.1.1 Guidelines for Preparation of EIS 7 2.1.2 Mineral Lease Conditions 8

2.2 Policies, Codes and Framework 8 2.2.1 General 8 2.2.2 Northern Territory Specific 10

3. EXISTING SITE CONDITIONS AND BASELINE 11 3.1 Existing Infrastructure 11 3.2 Environmental Baseline 11

3.2.1 Climate 11 3.2.2 Air Quality 12 3.2.3 Noise and Vibration 12 3.2.4 Landform and Soils 12 3.2.5 Land Uses 12 3.2.6 Flora 12 3.2.7 Fauna 13 3.2.8 Groundwater 14 3.2.9 Surface Water 14 3.2.10 Socio-economic 14 3.2.11 Indigenous and Non-Indigenous Cultural Heritage 15

4. STAKEHOLDER CONSULTATION 17 4.1 Consultation During Project Planning 17 4.2 Consultation During Operations 18 4.3 Consultation During Closure 18

5. DESCRIPTION OF CLOSURE DOMAINS 19

6. POTENTIAL ENVIRONMENTAL, ECONOMIC AND SOCIAL IMPACTS AFTER MINE CLOSURE 25 6.1 General Site Closure 25 6.2 Site Infrastructure 26

6.2.1 Aerodrome 26 6.2.2 Borefields 26

6.3 Extractive Workings and Hard Rock Pits 26 6.4 Water Dams and Ponds 27

Coffey Natural Systems 9014_10_v3.doc

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6.5 Waste Rock Storages 27

7. CLOSURE OBJECTIVES, OUTCOMES AND COMPLETION CRITERIA 29 7.1 Closure Objectives 29 7.2 Outcomes and Completion Criteria 29

8. CLOSURE AND REHABILITATION PROCESS 33 8.1 Progressive Rehabilitation 33

8.1.1 Constraints 33 8.1.2 Backfilling of Pits 33 8.1.3 Revegetation During Operations 35 8.1.4 Monitoring and Maintenance 38

8.2 Final Decommissioning 38 8.2.1 Site Infrastructure 39 8.2.2 Extractive Workings 39 8.2.3 Hard Rock Pits 40 8.2.4 Water Dams and Ponds 40 8.2.5 Waste Rock Storages 42 8.2.6 Exploration 43 8.2.7 Access and Haul Roads 43

8.3 Provision for Care and Maintenance 43

9. RISK ANALYSIS 45 9.1 General 49 9.2 Site Infrastructure 50

9.2.1 Borefield 50 9.3 Backfilled Pits 50 9.4 Open Pits 51 9.5 Water Dams and Ponds 51 9.6 Waste Rock Storages 51 9.7 Exploration 52

9.7.1 Drillholes, Pads, Sumps and Costeans 52 9.7.2 Tracks and Gridlines 52

9.8 Access and Haul Roads 53

10. POST CLOSURE MONITORING AND MAINTENANCE 55 10.1 Post-closure Monitoring 55 10.2 Maintenance 55

11. FINANCIAL PROVISION FOR CLOSURE 59 11.1 Cost Estimate 59 11.2 Funding of Security Payment 59 11.3 Public Liability Insurance 60 11.4 Financial Provision 60

12. SCHEDULE 61

13. REFERENCES 63


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Figures

1.1 Project location 2 1.2 Project layout 3 5.1 Closure domains 20 5.2 Arruwurra closure domains 21 5.3 Main Zone closure domains 22 8.1 Strip mining process 34 8.2 Cross-section of proposed abandonment bund 41

Tables

5.1 Proposed land uses for each domain after closure 23 7.1 Closure outcomes and completion criteria 30 8.1 Pit backfilling details 35 8.2 Waste rock storage details 42 9.1 Descriptors used to classify likelihood and consequence 45 9.1 Descriptors used to classify likelihood and consequence (cont’d) 46 9.2 Qualitative risk analysis matrix 46 9.3 Residual risks for each domain 47 10.1 Summary of proposed environmental and social monitoring program 56 11.1 Summary of estimated closure costs 59 12.1 Schedule for rehabilitation of each domain 61

Appendices

A Community consultation summary

B Species selected as suitable for revegetation

C Security cost calculation spreadsheets


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1. INTRODUCTION

Minemakers Australia Pty Ltd (Minemakers) proposes to develop the Wonarah Phosphate Project, hereafter referred to as ‘the project’, in the Barkly Tableland of the Northern Territory (Figure 1.1). The project involves the mining of two phosphate deposits, known as ‘Arruwurra’ and ‘Main Zone’. The project has an Indicated Joint Ore Reserves Committee (JORC) compliant resource estimate of 399 Mt at 21% phosphorite (P2O5) (15% cut-off grade) and will be developed over two discrete stages.

Stage 1 of the Wonarah phosphate project involves the mining of direct shipping ore (DSO) from up to 23 open pits, 4 at Arruwurra and 19 at Main Zone, two mobile crushing and screening plants and associated mine infrastructure (Figure 1.2). Based on currently defined resources Stage 1 has a mine life of around ten years and will produce approximately 19.9 Mt of DSO. Exploration currently underway may extend the mine life in excess of the ten year predicted mine life.

Stage 2, if pursued, will involve an expansion of the mining and processing operations to develop the lower grade ore, i.e., the non-DSO material, and possibly extend operations beyond the current Mineral Lease.

This report presents a mine closure and rehabilitation plan for Stage 1 of the project and has been prepared to support the Environmental Impact Statement for Stage 1. The report assumes that Stage 2 of the project does not proceed. If, at a later date, environmental approval is sought to develop Stage 2, detailed mine closure and rehabilitation planning for the expanded project will be undertaken at that time.

1.1 Premise for Mine Closure and Rehabilitation

The intent of mine closure and rehabilitation is to return the land to as close as is reasonably possible to its pre-disturbance condition, suitable for use by Traditional Owners and as habitat for flora and fauna. Infrastructure not requested to remain in place by Traditional Owners will be removed for sale and use elsewhere or disposed of.

It is intended that as much rehabilitation as possible will be undertaken progressively during the life of the mine. This will allow rehabilitation methods to be tested and refined to determine the most suitable, and successful, method for final rehabilitation. Careful management of topsoil during the life of the project will provide for revegetation from the seed bank in the soil, minimising the need for direct revegetation effort.

While rehabilitation and mine closure will continue to be refined during the life of the mine, generally disturbed areas will be rehabilitated as follows:

• Open pits–where pit design is amenable, strip mining or a variation on the process will be used, allowing open pits to be progressively backfilled with waste rock during mining. These areas will be contoured, topsoil will be spread and direct seeded to encourage revegetation with native species of local provenance. In pits too small for strip mining backfilling will be undertaken where possible; however, in the majority of pits some final void will remain.


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It is not economically viable to backfill all open pits. It has been estimated that were all remaining voids backfilled, upon cessation of mining, the cost would be in excess of $250 M. Where final voids will remain, rehabilitation will focus on ensuring geotechnical and geochemical stability and bunds will be established to ensure public safety.

• Waste rock storages–waste rock storages will remain at the completion of mining and these will be contoured, and spread with topsoil and direct seeded to encourage revegetation with native species of local provenance. There will be no requirement for onerous engineering measures (e.g., covers, underdrainage or seepage collection) due to the benign geochemical nature of the waste rock. Where possible, the landform of these storages will mimic that of the regional landscape.

The waste rock storages are designed to a maximum height of 20 m above the natural ground level. Lower elevations for these waste rock storages were considered; however, reducing the elevation significantly increases the disturbance area. As such, a 20 m elevation was considered an appropriate compromise between disturbance area and visual/landscape impact.

• Infrastructure areas–mine infrastructure will be preferentially provided to Traditional Owners to improve the infrastructure in the Wunara community. Infrastructure not required by Traditional Owners will be removed from site. Once infrastructure has been removed, any areas of contamination will be remediated and the areas will then be revegetated with native species.

1.2 Planning for Mine Closure

Mine closure planning will be a continuous process throughout the life of the mine that commences in parallel with project development, i.e., now. The closure plan for the project will be progressively refined and adapted throughout the life of the mine to ensure that the planning adapts to further site information as it becomes available during construction and operations, and to changes in regulations, stakeholder expectations, technology, knowledge of rehabilitation methods, and mine planning.

This mine closure and rehabilitation plan considers the relevant aspects of the following codes and best practice guidelines:

• Leading Practice Sustainable Development Program for the Mining Industry booklet series (Department of Industry, Tourism and Resources, 2007).

• The 10 principles of ‘Enduring Value’, i.e., the Australian minerals industry framework for sustainable development (MCA, 2004).

• Strategic Framework for Mine Closure (ANZMEC and MCA, 2000).

It also considers the Northern Territory-specific closure planning outlined in:

• Team NT: Technologies for the Environmental Enhancement of Mining in the Northern Territory Toolkit (NTMC, 2004).

• The Northern Territory Mines and Energy Security Calculation Form (DRDPIFR, 2009).


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• The Northern Territory Department of Regional Development, Primary Industry, Fisheries and Mines Advisory Note AA7-013: Security Calculation Procedure (DRDPIFR, 2007A).

1.3 Objectives of this Plan

The objectives of this mine closure and rehabilitation plan are to demonstrate that it is technically and economically feasible to successfully close and rehabilitate the project, and to develop a closure and rehabilitation process that can be built on during the life of the project.

1.4 Scope and Review of the Plan

The scope of this mine closure and rehabilitation plan is for Stage 1 of the project, with a projected mine life of ten years. It assumes Stage 2 of the project does not proceed.

The mine closure and rehabilitation plan will be reviewed, and if necessary revised, each year in conjunction with the Mining Management Plan, it will eventually form the basis of the final mine closure and rehabilitation plan.

Regular review of the mine closure and rehabilitation plan as part of the annual Mining Management Plan will allow the Northern Territory Department of Regional Development, Primary Industry, Fisheries and Resources (DRDPIFR) to review Minemakers’ bond so that it can be recalculated to reflect the current level of disturbance and rehabilitation liabilities. Review of the bond will be undertaken every year or as otherwise determined by the Minister for Primary Industry, Fisheries and Resources.

1.5 Structure of the Plan

This structure of the mine closure and rehabilitation plan is:

Chapter 1 – Introduction.

Chapter 2 – Outlines Minemakers’ legislative closure requirements, commitments and obligations, as well as performance standards.

Chapter 3 – Describes the existing site conditions.

Chapter 4 – Describes the consultation process to provide for community and stakeholder participation in mine closure and rehabilitation planning.

Chapter 5 – Describes the division of the Mineral Lease into different areas (domains) for consideration of closure management.

Chapter 6 – Details the main environmental, economic and social impacts that may be associated with mine closure.

Chapter 7 – Describes the overall closure objectives and the outcomes and completion criteria for each domain.

Chapter 8 – Details the proposed closure and rehabilitation process.


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Chapter 9 – Provides an assessment of the risks associated with closure of the mine.

Chapter 10 – Details post closure monitoring and maintenance requirements.

Chapter 11 – Describes Minemakers’ financial provision for closure of the mine.

Chapter 12 – Provides a notional schedule for closure of the mine.

Chapter 13 – Describes Minemakers’ long term management of the site.

Chapter 14 – References.


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2. CLOSURE REQUIREMENTS

Closure requirements for the project follow legislative requirements, relevant policies, codes and frameworks, conditions of land use permits, and Minemakers’ company requirements and performance standards. Each has implications for the development of this plan and the final mine closure and rehabilitation plan.

2.1 Legislative Requirements

The Mining Management Act requires mine closure and rehabilitation activities to be planned and undertaken This act also requires a security to be held by the Minister for Primary Industry, Fisheries and Resources to ensure that, among other things, the Minister has sufficient financial resources to cover the costs and expenses associated with complete rehabilitation of the mining site should it be required. The security is calculated based on the costs associated with rehabilitating the disturbed area at that time and the predicted disturbance area over the following 12 months. Progressive rehabilitation has the potential to significantly influence these costs.

The act also requires a certificate of closure to be issued upon completion of rehabilitation of a mining site. This certificate of closure will not be issued unless mine closure criteria have been adequately met. The issuing of a mine closure certificate also allows the Minister to release the security.

2.1.1 Guidelines for Preparation of EIS

The Environmental Impact Statement (EIS) Guidelines issued for the project by the Department of Natural Resources, Environment, The Arts and Sport (DNRETAS) in July 2009 outline requirements for decommissioning and rehabilitation planning in the EIS.

The primary outcome detailed in these guidelines is that the proponent is required to (DNRETAS, 2009):

Outline a time scale for rehabilitation and decommissioning of the project and for

determination of compliance with, and release from requirements of the appropriate

authorities. Final rehabilitation is required to be as close as possible to existing landscape

features.

The EIS guidelines require as detailed information as possible describing:

• How decommissioning and rehabilitation are to be integrated into the progression of the mining operation, as opposed to a separate phase upon completion of mining.

• Potential impacts of not meeting closure criteria.

• Management and monitoring safeguards to ensure rehabilitation objectives are achieved.


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2.1.2 Mineral Lease Conditions

Mineral Lease conditions were not available during the preparation of this plan, because they will not be issued until assessment, under the Environmental Assessment Act, of the project is complete. When the Mineral Lease is granted and any subsequent conditions are known, they will be included in future iterations of this mine closure and rehabilitation plan.

2.2 Policies, Codes and Framework

2.2.1 General

Leading Practice Sustainable Development Program for the Mining Industry Booklet Series

This booklet series developed by the Australian Government Department of Industry, Tourism and Resources (now the Department of Resources, Energy and Tourism) integrates environmental, economic and social aspects through all phases of mineral production. As such, the publications are designed to assist the mining industry to reduce the negative impacts of mineral production on the community and the environment by following the principles of leading practice sustainable management. The booklets from the series that most informed this report are:

• Biodiversity Management (2007) – guidelines addressing the broad issue of biodiversity management for mining operations, including environment protection and conservation legislation, flora and fauna and environmental offsets.

• Mine Closure and Completion (2006) – guidelines for the closure and completion of mines.

• Mine Rehabilitation (2006) – guidelines and practices for mine rehabilitation.

• Managing Acid and Metalliferous Drainage (2007) – addresses management issues related to the environmental impacts and remediation of acid and metalliferous drainage in the mining industry.

• Stewardship (2006) – guidelines to encourage the application of stewardship.

• Community Engagement and Development (2006) – addresses the key issues related to how mining companies interact with people (including community engagement and community development) and offers insights and approaches on the challenges that companies may encounter as they engage with local communities and seek to contribute to their long-term development.

Enduring Value

Enduring Value is a sustainable development framework, developed by the Australian minerals industry to provide guidance to industry managers about sustainable development in the minerals sector.

Enduring Value sets out ten Sustainable Development principles that aim to ensure that investments in minerals projects are financially profitable, technically appropriate, environmentally sound and socially responsible (MCA, 2004). While all the principles in Enduring Value are relevant to planning and procedures for mine closure, it is principle


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six – to seek continual improvement of environmental performance – that provides specific guidance about this. Elements 6.3 and 6.5 are most relevant to this closure plan and are outlined below.

Element 6.3 – Rehabilitate land disturbed or occupied by operations in accordance with appropriate post-mining land uses:

• Consult relevant stakeholders and develop a closure plan that clearly defines the post-closure land use.

• Where appropriate, rehabilitate progressively over the life of the operation:

– Monitor success criteria agreed with relevant stakeholders. – Report performance.

• Undertake and support research into land and water rehabilitation practices.

• Use appropriate technologies to reduce negative environmental impacts and improve site rehabilitation techniques.

• Manage and, where appropriate, rehabilitate historical disturbances to an appropriate standard.

Element 6.5 – Design and plan all operations so that adequate resources are available to meet the closure requirements of all operations:

• Plan operations to: minimise costs and risks; comply with relevant law, standards and guidelines; maximise sustainable development opportunities; and deliver post-closure landforms that are safe and stable from physical, geochemical and ecological perspectives.

• Provide adequate resources to achieve social objectives of closure, including any costs associated with community dislocation.

• Set aside funds externally held and not accessible for other purposes to implement the closure plan and to undertake post closure monitoring and maintenance.

• Periodically review closure plans in the light of changing regulatory requirements and community expectations.

Minemakers, while not a signatory to the Enduring Value framework, will be guided by the Enduring Value principles and implementation advice.

ANZMEC and MCA Strategic Framework for Mine Closure

The Australian and New Zealand Minerals and Energy Council (ANZMEC) and the Minerals Council of Australia (MCA) have jointly developed a Strategic Framework for Mine Closure (ANZMEC and MCA, 2000). The framework is designed to provide a broadly consistent approach to mine closure across the various Australian jurisdictions.

The framework is structured around a set of objective and principles grouped under six key areas:

• Stakeholder involvement. • Planning. • Financial provision.


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• Implementation. • Standards. • Relinquishment.

This mine closure and rehabilitation plan draws upon the principles outlined in the ANZMEC and MCA strategic framework, as appropriate.

Other Performance Standards

Other performance standards that, to a lesser extent, have informed the writing of this report are:

• Standards Australia’s Environmental risk management – Principles and process (HB 203:2006) (Standards Australia, 2006A) – presents an integrated framework of principles, practices and criteria for implementing best practice in environmental risk management.

• National Environment Protection Measure of Assessment of Site Contamination (NEPC, 1999) – aimed at establishing a nationally consistent approach to site contamination assessment and provides a recommended general process for assessment of site contamination.

2.2.2 Northern Territory Specific

This mine closure and rehabilitation plan has considered the Northern Territory closure and rehabilitation guidelines and processes identified in Section 1.3.


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3. EXISTING SITE CONDITIONS AND BASELINE

The following section describes the site conditions prior to the commencement of mining pertinent to mine closure and rehabilitation; for a full description of existing site conditions refer to the Wonarah Phosphate Project EIS (CNS, 2009).

3.1 Existing Infrastructure

Exploration has been undertaken on the site of the project for over 40 years, as such approximately 105 km of exploration tracks traverse the site. There is an exploration camp on site, with power supplied by generators and water from a groundwater bore.

The Barkly Highway provides access to the site, with the closest major centres being Tennant Creek to the west and Mt Isa to the east.

3.2 Environmental Baseline

3.2.1 Climate

Average wind speeds for the project area are between 11 km/h and 16 km/h. Winds are generally fresher in the morning than in the afternoon. Wind direction is predominately southeasterly in the morning and afternoon, throughout the year. The maximum peak gust recorded is 68 km/h.

The Davenport and Murchison Ranges Bioregion (encompassing Wonarah) is characterised by long, hot wet seasons (with mean maximum of 38°C and minimum of 25°C) and cool mild dry seasons (with mean maximum of 25°C and minimum of 12°C) (BOM, 2009). Hot weather generally persists from November through until March before becoming mild to cool between April and September.

The Davenport and Murchison Ranges Bioregion is characterised by semi-arid regions in the south and subtropical regions to the north, with 70 to 80% of rainfall occurring in the wet season. While the climatic conditions of the north are generally well-defined monsoonal wet and dry seasons, the rainfall patterns of the southern regions are generally more erratic and less defined.

Rainfall in the region tends to be seasonal and although the mean annual rainfall values are often minimal, in comparison high intensity rainfall events can be significant. Rainfall intensity data shows that short duration rainfall intensities in excess of 150 mm/h have been recorded.

The project area is located within a region that is occasionally subject to tropical cyclones and tropical depressions. Although infrequent, rain events associated with the cyclones could have an impact on the project area.


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3.2.2 Air Quality

The project area is remote from significant pollution sources. The existing air quality in the vicinity of the project area is relatively pollutant free and is typical of a remote, semi-arid rural environment. Dust generated by wind erosion of exposed surfaces is the main air pollutant present. Other pollutants sources are combustion emissions from bushfires and minor emissions from vehicles travelling along the Barkly Highway and carrying out exploration activities.

3.2.3 Noise and Vibration

No significant, permanent man-made noise sources are located at or near the project, other than passing vehicles travelling on the Barkly Highway and noise when exploration activities are underway. The only ongoing noise present is caused by wind blowing over vegetation and noises from insects and birds.

3.2.4 Landform and Soils

The landform of the project area has a general low relief, although small rocky outcrops are locally common. Across the Barkly Tableland there is generally only a very gentle relief, which varies less than 50 m in elevation from the highest to lowest point (Edgoose, 2003).

Soils within the project area have been identified into four major soil classifications: Kandosols, Vertosols, Calcarosols and Rudosols. Kandosols and Rudosols dominate the sand plains within the project area, while Vertosols and Calcarosols are restricted to areas subject to inundation (e.g., ephemeral lakes) and two localities in the southern end of the project area, respectively. Rudosols were the only soil type in the project area assessed as being particularly susceptible to erosion.

3.2.5 Land Uses

Traditional Owners use the Mineral Lease and surrounds for hunting and gathering and for accessing culturally significant sites. While the Mineral Lease area is suitable for grazing beef cattle, no pastoral activities currently occur on the land. The borefield area to the north of the Barkly Highway is used for grazing beef cattle.

3.2.6 Flora

The distribution and composition of vegetation within the project area is influenced by soil types. Field and desktop surveys identified eight vegetation communities within the project area:

1. Sand plains supporting Eucalyptus and Acacia open woodland over hummock grassland.

2. Black soil and clay pans supporting coolibah low open woodland over grassland.

3. Calcareous plains supporting supplejack low open woodland over open grassland.

4. Ephemeral lakes supporting coolibah low open woodland over grassland.

5. Rocky rises supporting Acacia and mallee shrubland over hummock grassland.


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6. Low open woodland supporting Corymbia opaca, (bloodwood) with Triodia pungens (soft spinifex) hummock grassland understorey.

7. Low open shrubland supporting Chenopod with Chenopodium auricomum (bluebush) with ephemeral grassland understorey.

8. Astrebla pectinata (mitchell grass) grassland.

The vegetation communities described above are widespread and common across the Davenport Murchinson Ranges bioregion.

One record of Sporobolus latzii is listed in the NT Parks and Wildlife Flora Atlas and this record is within a cultural exclusion zone. This is the only known collection site of this species in Australia. Although targeted searches were performed as part of the surveys no specimens were identified.

No weed species listed under the Northern Territory Weeds Management Act have been identified within the project area. However, two environmental weed species, Cenchrus ciliaris (buffel grass) and Aerva javanica (kapok bush) were recorded during the field surveys.

3.2.7 Fauna

The NT Parks and Wildlife Fauna Atlas identified 163 species within the project area and surrounds. Twelve of these species are listed under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and a further eight species are listed under the Territory Parks and Wildlife Conservation Act (TPWC). Two species (both listed as near threatened under the TPWC Act) have been recorded in the project area, Rattus villosissimus (long haired rat) and Aspidites ramsayi (woma). Two species of conservation significance were recorded during the field surveys, Ardeotis Australia (Australian bustard) (listed as vulnerable under the TPWC Act) and Onychogalea unguifera (northern nail-tailed wallaby) (listed as near threatened under the TPWC Act). The field surveys identified no habitats of listed ecological importance.

No species listed under the EPBC Act were recorded during the field surveys. However, ephemeral lakes are likely to be important to migratory species listed under the EPBC Act during the wet season. An ephemeral lake is located approximately 5 km to the northwest of the Arruwurra deposit and another approximately 10 km northeast of the northern borefield.

Traditional Owners identified local fauna of cultural significance for their utilitarian values. Larger fauna species such as kangaroo, Australian bustard, sand goanna and other large dragons are still hunted by the Traditional Owners. The ephemeral lakes within the cultural exclusion zones are considered an important hunting ground as they provide seasonal refuge to larger species. The Traditional Owners consulted during the field surveys identified no species of mythical significance.

Five introduced fauna were recorded within the project area during field surveys: camels, cows, donkeys, cats and foxes. Cats and foxes are likely to be in low abundance in the area.


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3.2.8 Groundwater

Groundwater offers the only source of reliable water within the region. Groundwater recharge is predominantly from rainfall infiltration; recharge from surface water will occur locally in the vicinity of the major rivers and, after rainfall events, from minor drainage lines and marshy areas.

Groundwater quality over the tableland is generally fresh to brackish and groundwater levels in the region are extremely variable, ranging from about 25 to over 100 m below ground level. The groundwater level to the north of Mineral Lease is reasonably consistent, lying between 49 and 65 m below ground level in the vicinity of the proposed borefield. Groundwater levels at the Mineral Lease are more variable, varying from 3 to 63 m below ground level.

There are two environmentally sensitive areas (Kerringnew Swamp and Oolgoolgarri Swamp) that have the potential to be impacted by the project’s groundwater use. The closest of these environmentally sensitive areas to the northern borefield is the Kerringnew Swamp, located 10 km to the northeast. However, results of a monitoring bore at this location suggest the swamp is an ephemeral surface water feature and is not related to groundwater. It would therefore not be expected to be influenced by changes in the underlying groundwater level; however, monitoring of the site will continue during operation of the project. The Oolgoolgarri Swamp is located 37 km east of the northern borefield and not likely to be affected.

3.2.9 Surface Water

No significant watercourses traverse the project area, with the closest watercourse being the ephemeral Ranken River approximately 60 km to the east and ephemeral Playford River 87 km to the north. All the on site creeks and drainage lines are relatively minor and ephemeral in nature and are likely to only carry runoff following significant rainfall events. The drainage in the project area flows to several large shallow lakes, very few of which are permanent; however, some lakes are known to retain water for extended periods after rain. Seasonally flooded swamps occur in the northwest and southwest of the project site, around Arruwurra.

The project is located in the Barkly Surface Water Management Area (SWMA). Under the SWMA management framework, there are no water quality objectives to meet environmental and other public benefit outcomes. There is no major water storage, diversion or supply infrastructure within the Barkly SWMA and the volume of surface water used is less than 0.1% of the mean annual runoff. There are no current surface water licences within the Barkly SWMA and any surface water use is for stock watering.

3.2.10 Socio-economic

The project area is on the Barkly Tableland, a remote region of the Northern Territory. The closest populated community is Wunara, a small Aboriginal settlement located approximately 10 km east from the Mineral Lease boundary, adjacent to the Barkly Highway. The population residing in the community fluctuates from 2 to 30 people according to the season. Members of the Wunara community are Traditional Owners of the land subject to the Mineral Lease and northern borefield. The project is also surrounded by a number of pastoral properties and unallocated Crown land.


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The Barkly Tableland covers a large area of the central eastern Northern Territory. The major service centre for the region is the town of Tennant Creek (approximately 240 km west of the project area). The region is sparsely populated with the major sources of income for the region generated from grazing, mining and tourism.

3.2.11 Indigenous and Non-Indigenous Cultural Heritage

The project area is located within the region associated with the Arruwurra people. The project area and surrounds is known to contain sites of mythological and archaeological significance. Through the Central Land Council (CLC), in consultation with Traditional Owners, six sacred sites were identified close to the Mineral Lease. These sites have consequently been incorporated into the cultural exclusion zones and are located outside of the Mineral Lease; no infrastructure or activities related to the project will occur in these areas. A search of the Aboriginal Areas Protection Authority (AAPA) Heritage Database identified two registered sites to the north of the Barkly Highway.

An archaeological survey identified six low density silcrete knapping areas within and adjoining the Mineral Lease. Of these, one is of moderate scientific significance (outside the Mineral Lease) and the remaining five are of low scientific significance.

A search of the Australian Heritage Database and the NT Heritage Register identified no sites of non-Indigenous cultural heritage within the project area.


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4. STAKEHOLDER CONSULTATION

Mine closure planning has been conducted in consultation with stakeholders to meet the following final rehabilitation and mine closure objectives:

1. Meet their perceptions of a suitable end land use for the project area.

2. Incorporate their requirements (e.g., retention of certain infrastructure for use by local land users).

3. Keep them informed of the achievement of mine closure criteria.

Details of the results of this consultation are provided in Section 4.1. The ongoing closure consultation process through the life of the project will aim to keep stakeholders informed by developing and agreeing on final closure objectives and criteria with them, and on a process for the handover and relinquishment of the Mineral Lease following closure.

The specific objectives of this consultation are to ensure that:

• Stakeholders are included in the closure process, have their interests considered and have the opportunity to participate meaningfully in the process.

• All outcomes agreed to are achievable and sustainable, and ensure that the long-term integrity of the site is maintained.

• Requirements of the government and community are met.

The closure consultation process will be part of Minemakers’ broader stakeholder consultation, involving both formal and informal processes. This is summarised below and also documented in the Wonarah Phosphate Project EIS (CNS, 2009).

4.1 Consultation During Project Planning

During the planning for the project, consultation has included a broad range of stakeholders and issues, including mine closure planning. A database is being, and will continue to be kept, to record all stakeholder contact.

The broad outcomes of these consultation activities include:

• Increased government and community awareness and understanding of the project. • Identification of areas of concern to Traditional Owners and other stakeholders. • Building relationships with local and peripheral communities. • Identification of potential employment opportunities for local Indigenous people. • Opportunities for members of the local community to voice opinions and concerns.

The main concerns about mine closure raised during this consultation have been:

• Whether or not open pits will be backfilled during, or at the completion of, mining. • The geochemical stability and general safety of post-mining landforms. • The likelihood of successful rehabilitation given the climatic extremes of the project

area.


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The main positive issues about mine closure raised during this consultation have been the potential:

• Use of infrastructure by Traditional Owners after mining. • For employment of Indigenous people during rehabilitation trials, and potential

business opportunities that may arise from this.

Further details of consultation undertaken during the preparation of the EIS and relating to closure or rehabilitation are provided in Appendix A.

4.2 Consultation During Operations

As part of the mine closure and rehabilitation process, consultation during operations will include the following stakeholder groups as a minimum:

• Traditional Owners (the Arruwurra Aboriginal Corporation), the CLC and NLC (for areas north of the Barkly Highway).

• Relevant Northern Territory government agencies, i.e., DRDPIFR and DNRETAS.

• Other users of the land, including nearby pastoralists and the Barkly Shire Council.

• Company representatives, including employees, contractors, management and shareholders.

Specifically, Minemakers will:

• Identify and engage these and other stakeholders in a consultation program, where their concerns and interests can be considered during mine closure planning.

• Prepare a consultation plan that outlines stakeholder issues in relation to the closure of the mine, describes the consultation strategies used to engage stakeholders and provides a schedule for regular stakeholder consultation.

The nominated timing for the preparation of the closure-specific consultation plan is within 24 months of the commencement of operations.

4.3 Consultation During Closure

While it is intended to undertake as much progressive closure and rehabilitation as possible during operations, by its nature closure rehabilitation will primarily happen once operations are complete. In addition, while every effort has been made to plan and hence describe operations accurately, it is foreseeable that some changes will occur to the current project description during the life of the mine.

In recognition of this, and to ensure the views and opinions of all stakeholders are sought when they have access to up-to-date information of the proposed timing and nature of closure, specific closure consultation will be undertaken no less than two years prior to cessation of operations. In addition, closure and rehabilitation activities (e.g., monitoring) will be ongoing for no less than two years after the cessation of operations. This will require continued consultation with a number of stakeholders, such as Traditional Owners and the Northern Territory Government.


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5. DESCRIPTION OF CLOSURE DOMAINS

The project has been broadly divided into categories, generally known as domains, for closure. For consistency, these domains match those suggested by the Northern Territory Government (DRDPIFR, 2007; DRDPIFR, 2009). The domains and their components are:

• Site infrastructure, including:

– Accommodation village. – Administration offices. – Aerodrome. – Borefields. – Crushing and screening plants. – Main workshop and stores area. – Power station. – Sewage and water treatment plants.

• Extractive workings, including sand, gravel or clay borrow pits.

• Hard rock pits.

• Water dams and ponds, there are no water dams or ponds on site; this domain refers to surface water management structures.

• Waste rock storages, including non-DSO ore stockpiles.

• Exploration, including:

– Drillholes, pads, sumps and costeans. – Tracks and gridlines.

• Access and haul roads.

These areas are shown in Figure 5.1 and 5.2 and 5.3 for Arruwurra and Main Zone, respectively. The proposed end land uses for each domain are outlined in Table 5.1. Some of the domains do not appear on the figure, this is due to the scale of the figure being too great to show small detailed domains such as sediment ponds, not that they do not exist or have been missed. Exploration is also not included on these figures.

Future consultation with the Traditional Owners may result in some infrastructure being left behind by Minemakers to be utilised by the Wunara community. However, this will be determined after significant consultation with the Traditional Owners and a definitive decision will be made closer to the time of closure. At this stage the base case is that Minemakers will remove all infrastructure from the Wonarah site.


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Table 5.1 Proposed land uses for each domain after closure

Domain Component Proposed land use

Site Infrastructure Accommodation village Traditional land use and resilient, self-sustaining native vegetation of local provenance providing suitable habitat for fauna.

Administration offices

Aerodrome Downgraded to airstrip and left for use by landowners.

Borefield Surrounding areas to be available for return to pastoral use.

Crushing and screening plant

Traditional land use and resilient, self-sustaining native vegetation of local provenance providing suitable habitat for fauna.

Main workshop and stores area

Power station

Sewerage, water treatment plant

Extractive workings

Borrow pits Stabilised modified landform providing traditional land use and resilient, self-sustaining native vegetation of local provenance.

Hard rock pits Backfilled pits Stabilised modified landform providing traditional land use and resilient, self-sustaining native vegetation of local provenance.

Open pits Pits: open voids.

Abandonment bund: resilient, self-sustaining native vegetation of local provenance.

Water dams and ponds

Surface water management structures

Ephemeral drainage.

Waste rock storages

Waste rock storages Stabilised modified landform with resilient, self-sustaining native vegetation of local provenance.


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Table 5.1 Proposed land uses for each domain after closure

Domain Component Proposed land use

Exploration Drillholes, pads, sumps and costeans

Traditional land use and resilient, self-sustaining native vegetation of local provenance.

Access tracks and gridlines

Access and haul roads

Access road Traditional land use and resilient, self-sustaining native vegetation of local provenance, some access tracks may be left to facilitate Traditional Owner’s access to sacred sites.

Haul roads Traditional land use and resilient, self-sustaining native vegetation of local provenance. May be left to facilitate Traditional Owner’s access to sacred sites.


6. POTENTIAL ENVIRONMENTAL, ECONOMIC AND SOCIAL IMPACTS AFTER MINE CLOSURE

The closure of an operation such as the Wonarah Phosphate Project will have a number of environmental, economic and social issues and risks associated with it. The potential environmental, socio-economic impacts considered in this chapter relate to issues for each domain that may remain after mine closure. However, it should be noted that the potential impacts do not take into consideration the proposed avoidance, mitigation and management measures that will be implemented by Minemakers.

6.1 General Site Closure

A number of potential impacts may occur across most or all of the closure domains; to avoid repetition they are not mentioned for each individual domain. These are:

• Air quality:

– Decrease in air quality due to dust emissions from disturbed and poorly rehabilitated land.

• Cultural heritage:

– Reduced amenity of sacred sites near the project area.

• Fauna:

– Increased abundance of introduced species. – Reduced species abundance and/or diversity compared to baseline.

• Flora:

– Reduced species abundance and/or diversity compared to baseline. – Introduction of new weed species and increased weed density and distribution. – Increased potential for fire, or changed fire characteristics.

• Groundwater:

– Contamination of groundwater resources due to seepage from land contaminated by mining operations.

• Landscape and visual amenity:

– Altered landscape and reduced visual amenity compared to baseline, particularly as a result of waste rock storages.

• Socio-economic – positive:

– Reduced project-related traffic on the Barkly Highway. – Provision of access tracks to sacred sites. – Lasting socio-economic benefits to Traditional Owners.


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• Socio-economic – negative:

– Reduced employment opportunities. – Reduced spending in the local community. – Increased human health (i.e., safety) risks. – Changed population in local communities. – Potential burden on government should Minemakers not be able to provide post-

closure monitoring and maintenance costs.

• Surface water:

– Adverse effects on aquatic fauna and habitats due to increased sediment loads in watercourses resulting from ineffective rehabilitation of disturbed land.

– Contamination of watercourses due to runoff from land contaminated by mining operations.

Impacts specifically related to domains are identified in the following sections; where individual domains are not addressed no additional significant impacts have been identified other than those described above.

6.2 Site Infrastructure

6.2.1 Aerodrome

A positive socio-economic impact after the closure of the mine is likely to be the provision of the airstrip to the landowners, once infrastructure has been removed and the aerodrome has been downgraded to an airstrip. This could be used as an emergency landing strip and evacuation point for the Royal Flying Doctor Service, as well as a regular point of access for the provision of supplies by air.

6.2.2 Borefields

Potential impacts specifically related to the borefields after closure are:

• Flora and fauna:

– Bores may not be appropriately capped, resulting in increased vegetation growth and attraction of grazing animals, with consequent changes to the flora and fauna of the area.

• Groundwater:

– Bores may not be appropriately capped, resulting in uncontrolled release and loss of groundwater.

6.3 Extractive Workings and Hard Rock Pits

Potential impacts that may remain after mine closure that are relevant to the final pit voids and extractive working borrow pits include:

• Fauna:

– Fauna deaths due to entrapment.


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• Flora:

– Failure to achieve self-sustaining vegetation on the backfilled pits and abandonment bunds, leading to reduced ecological function in these areas.

• Groundwater:

– Contaminants in pit water during the wet season affecting the quality of groundwater resources.

• Surface water:

– Altered flow regimes from baseline due to changes in landform and open voids, with consequent downstream impacts as a result of diversion and/or retention.

6.4 Water Dams and Ponds

Potential impacts, all of these will be ephemeral in nature and only during the wet season due to the nature of the climate, that may remain after mine closure related to the retention of surface water management structures include:

• Fauna:

– Attraction of grazing animals to water, with consequent changes to species composition and vegetation condition.

– Creation of mosquito breeding habitat.

• Surface water:

– Retention of surface water flow after rainfall, with consequent downstream impacts.

6.5 Waste Rock Storages

Potential impacts that may remain after mine closure related to waste rock storage areas include:

• Surface water:

– Adverse effects on aquatic fauna and habitats due to increased sediment loads in watercourses resulting from ineffective rehabilitation of waste rock storage areas.

– Altered flow regimes from baseline due to changes in landform.

• Landscape and visual amenity:

– Altered landscape and reduced visual amenity compared to baseline.


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7. CLOSURE OBJECTIVES, OUTCOMES AND COMPLETION CRITERIA

7.1 Closure Objectives

The objectives of the closure and rehabilitation process are to ensure the:

• Protection of human health and safety.

• Progressive rehabilitation of the site during operations.

• Vegetation is resilient, self-sustaining and comparable to the surrounding areas.

• Project does not compromise the quality and quantity of surface water or groundwater to existing users and water dependent ecosystems.

• Need for long term monitoring and maintenance is reduced through design and construction of mine waste landforms that are physically and chemically stable.

• Altered landforms (waste rock storages) are contoured and, recognising that the regional landscape is gently undulating and relatively flat with little to no significant elevation, as inconspicuous as possible.

• Residual risks and liabilities are identified and can be readily controlled.

• Mine closure process and lease relinquishment occurs in a cost-effective and efficient manner.

• Full cost of decommissioning and rehabilitation is understood and that a mechanism for funding exists.

• Development of an environmental monitoring and reporting program which is focused towards demonstrating the achievement of closure outcomes.

7.2 Outcomes and Completion Criteria

Closure outcomes and completion criteria have been developed for each domain (Table 7.1); these outcomes represent Minemakers’ current public commitments for the closure of the project. The outcomes and criteria:

• Have been written to be as clear and measurable as practical. • Will form the basis for conditions of lease relinquishment.

During the closure planning process throughout the life of the mine the outcomes and criteria will be reviewed and revised to take into consideration the results of trials and investigations, changes in mine planning, and feedback from stakeholders on final land uses.


Table 7.1 Closure outcomes and completion criteria Domain and Component Outcome Completion Criteria

General

All site components The community and future generations are left with no residual liability for site rehabilitation or maintenance.

Government acceptance of mine completion report which demonstrates achievement of all completion criteria.

Public health and safety is not endangered. Audit shows any remaining mining infrastructure is left in a safe and secure manner, and discourages public access.

Landscape function and vegetation is resilient, self-sustaining and comparable to the surrounding areas.

Landscape and vegetation assessment undertaken and reported to show function is resilient, self-sustaining and comparable to the surrounding areas.

No increase in contamination levels above baseline conditions.

Site contamination survey (conducted to Australian Standards) demonstrates no elevated levels of selected contaminants.

Full awareness in community regarding mine closure concept and timing.

Stakeholder engagement records show ongoing consultation and engagement in closure planning process.

Site Infrastructure

Accommodation village All infrastructure removed. Audit of domain against final closure plan to confirm the accommodation or related infrastructure does not remain on site.

Administration offices All infrastructure removed. Audit of domain against final closure plan to confirm the Administration offices or related infrastructure does not remain on site.

Aerodrome All infrastructure removed except that required for function as airstrip.

Audit of domain against final closure plan to confirm only required airstrip infrastructure remains on site.

Borefields No adverse change in ecological condition. Field surveys show no increase in numbers of grazing animals above baseline conditions and consequent impacts from this.

Borefields decommissioned. Audit of domain against final closure plan shows only borefields required remain in use, and those not required are capped in accordance Northern Territory Government guidelines (e.g., DRDPIFR, 2007B)

All infrastructure removed unless required for end land use or requested and agreed between Minemakers and Traditional Owners.

Audit of domain against final closure plan to confirm only required borefield infrastructure remains on site.


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Crushing and screening plants

All infrastructure removed. Audit of domain against final closure plan to confirm no crushing and screening plant infrastructure remains on site.


All infrastructure removed. Audit of domain against final closure plan to confirm no workshop or stores area infrastructure remains on site.

Power station All infrastructure removed. Audit of domain against final closure plan to confirm no power station infrastructure remains on site.

Sewage, water treatment plant

All infrastructure removed. Audit of domain against final closure plan to confirm no sewage and water treatment plant infrastructure remains on site.

Extractive workings Borrow pits Landscape function and vegetation is resilient and

self-sustaining and comparable to surrounding area. Left with no risk of becoming a trap for people or fauna.


Hard rock pits

Backfilled pits

Landscape function and vegetation is resilient, self-sustaining and comparable to surrounding area.


Open pits Water quality in open pit voids is suitable and does not lower surrounding water quality or impact fauna that may use them, e.g., birds and amphibians.

Monitoring post closure demonstrates that pit water is of suitable quality. No creation of long-term mosquito breeding habitat.

No impact on water quantity or quality available to existing groundwater users due to pit inflow.

Monitoring post closure of site bores demonstrates there is no change from baseline in terms of quality or quantity and audit shows that recharge is as per predictions.

No injuries or deaths resulting from pit stability or ease of access to pit.

Abandonment bund constructed around the pit perimeter to restrict inadvertent access to the pit void, with the location of the bund to be determined by a geotechnical specialist.

Pit ramps blocked to prevent inadvertent access.

Geotechnical assessment of pit at closure demonstrates stability is acceptable.


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Surface water storage areas rehabilitated to provide habitat for wetland bird species.

Vegetation and fauna assessment undertaken and report to show areas function as habitat for wetland bird species.

No creation of long-term mosquito breeding habitat.

Audit shows that where possible and necessary water structures are rehabilitated to provide polishing wetlands.

All surface water structures remaining in place are physically stable and safe to fauna and humans.

Audit of structures to confirm stability and safety acceptable.

Waste rock storages

Waste rock storages Waste rock storages are physically and chemically stable.

Geotechnical assessment shows that waste rock storages are physically stable.

Monitoring to demonstrate no adverse impact to the quality and quantity of surface or groundwater caused by waste rock storages to water-dependent ecosystems.

Exploration

Drillholes, pads, sumps and costeans

Ecosystem and landscape function is resilient and self-sustaining and comparable to surrounding area.

Audit shows all exploration drill holes capped and drill pads rehabilitated in accordance with Northern Territory Government guidelines (e.g., DRDPIFR, 2007B; DRDPIFR, 2007C; respectively).

Audit shows all costeans and sumps backfilled or battered and rehabilitated in accordance with Northern Territory Government guidelines (e.g., DRDPIFR, 2007D).

Access tracks and gridlines Ecosystem and landscape function is resilient and self-sustaining and comparable to surrounding area.

Audit shows all access tracks, grid lines and drill pads rehabilitated as per Northern Territory Government guidelines (e.g., DRDPIFR, 2007E).


Access road Access road rehabilitated unless required for end land use by Traditional Owners.

Audit shows all access road infrastructure no longer required is decommissioned.

Haul roads All haul roads and other site roads rehabilitated unless required for end land use by Traditional Owners.

Audit shows all haul road and other site road infrastructure rehabilitated.


8. CLOSURE AND REHABILITATION PROCESS

8.1 Progressive Rehabilitation

Progressive rehabilitation of the site during the operational life of the mine will be important to demonstrate the success of closure strategies prior to final closure and to enable adjustments to strategies as a result of the experience gained. Progressive rehabilitation will also reduce the long-term closure liability required of Minemakers after the mine closes.

8.1.1 Constraints

The ability to progressively complete large areas of rehabilitation during operations will be influenced by the mine schedule, availability of areas (e.g., some areas of permanent waste rock storages will not be available until closure), the availability of materials and site conditions, particularly rainfall that is essential in the establishing vegetation cover.

The success of revegetation activities will be heavily reliant on successful rainfall in the following wet season(s). Avoiding wild fire in the years following revegetation will also be critical to ensuring the long-term success of the revegetation activities.

8.1.2 Backfilling of Pits

For some pits a strip mining process or a variation on the process will be used. This process involves the progressive backfilling and rehabilitation of pits as mining advances (Figure 8.1). For these pits, rehabilitation and mine closure will therefore be completed within 12 months of cessation of operations, subject to requirements for monitoring of landforms and rehabilitation performance over future years.

Smaller pits will be mined using conventional open pit methods. For these pits, the extent to which they will be backfilled and progressively rehabilitated will be dependent upon the mining schedule and the economic viability of backfilling. Generally, voids associated with open pits will be larger than those that remain for pits mined via the strip mining process. The mining of multiple open pits will; however, provide opportunity for the initial pre-strip waste from one pit to be backfilled into the void created by a mined out pit. However, in many cases, the haulage distance between successive pits will be significant and backfilling may be less cost effective than constructing waste rock storages adjacent to the active pits.

Table 8.1 shows the details of the proposed backfilling of pits.


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Table 8.1 Pit backfilling details

Pit Total Extraction

Volume

(m3)

Total Disturbance

Area

(ha)

Percentage Backfilled

(%)

Remaining Volume

(m3)

Remaining Disturbance

Area

(ha)

Year Complete

Arruwurra

AP 1 13,424,932 74 40 8,069,323 51.8 2013

AP 2 821,589 6 0 821,589 6.0 2013

AP 3 3,110,480 26 78 684,041 8.3 2013

AP 4 727,568 7 100 0 0.0 2011

Main Zone

MZP 1 12,398,912 39 35 8,098,393 49.2 2018

MZP 2 2,507,912 11 0 2,507,912 11 2017

MZP 3 3,314,222 14 80 649,866 5.8 2014

MZP 4 3,744,335 14 0 3,744,335 14 2019

MZP 5 16,128,146 49 44 9,007,220 36.8 2015

MZP 6 25,392,041 80 62 9,750,265 18.6 2016

MZP 7 4,124,352 14 0 4,124,352 14 2018

MZP 8 5,078,658 16 0 5,078,658 16 2017

MZP 9 5,207,406 18 0 5,207,406 18 2018

MZP 10 2,158,076 9 0 2,158,076 9 2015

MZP 11 9,323,137 27 83 1,623,106 4.8 2017

MZP 12 3,901,878 14 100 0 0.0 2018

MZP 13 6,797,239 20 66 2,339,697 15.3 2018

MZP 14 2,024,905 9 0 2,024,905 9 2019

MZP 15 4,200,356 14 57 1,823,891 23.2 2019

MZP 16 7,116,354 24 0 7,116,354 24 2017

MZP 17 4,550,130 21 0 4,550,130 21 2015

MZP 18 4,413,889 20 0 4,413,889 20 2012

MZP 19 20,554,265 70 25 15,512,893 64.5 2014

Note: Any apparent errors are a consequence of rounding.

8.1.3 Revegetation During Operations

Where practicable disturbed areas and/or areas no longer required for mining will be rehabilitated concurrently with continuing activities on other sections of the site. Many of the rehabilitation measures have been designed to indirectly assist and enhance the final post-closure rehabilitation of the mine site. For example, by reducing erosion, establishing native vegetation and controlling surface water runoff (all of which are aspects of progressive rehabilitation) during the day to day operation of the mine, potential future problems are likely to be minimised.

The general proposed process of revegetation during operations is described below.

Site Preparation

Sites available for progressive rehabilitation will be prepared by:


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• Deep ripping areas of compacted soil. • Reprofiling ripped or stockpiled soil. • Respreading topsoil. • Contour furrowing or ripping respread areas.

Revegetation

Following site preparation, the revegetation of sites will occur by one of two methods:

• Revegetation from seed stock in respread topsoil. • Revegetation from direct seeding or planting.

In cases where seed collection and direct seeding are used, threatened species will be targeted for revegetation.

Revegetation from Seed Stock in Respread Topsoil

The successful removal, storage and subsequent re-spreading of topsoil removed during construction and mining will assist revegetation from seed stock in soil. This revegetation will depend on the natural storage of seed in the topsoil; revegetation will be best when favourable climatic conditions persist before, during and after the stripping process.

Procedures to maximise the potential for revegetation from seed stock in topsoil are (LES, 2009):

• Stripping:

– Topsoil will be stripped to a depth of about 100 mm and include ground cover plants. This is a general guide only and topsoil removal will be maximised where possible, 100 mm is, however, the average depth of topsoil.

– Subsoil will be stripped to a depth of about 300 mm, as above, this is an average depth.

– Soil will be stripped during periods where it is not raining where possible to minimise the likelihood of erosion by surface runoff and destruction of soil structure.

• Storage:

– Topsoil and subsoil will be stored separately.

– Soil stockpiles will be stored away from drainage areas.

– Soil stockpiles will be low mounds less than 2 m high to allow the seed bank to germinate.

– Soil stockpiles will be allowed to revegetate to protect against erosion and maintain soil quality.

– Erosion controls will be placed around topsoil and subsoil storage areas.


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• Respreading:

– The period of exposure of topsoil will be minimised, as soil components such as microorganisms, seeds and organic matter will deteriorate with time; where possible, stripped soil will be respread within three to six months of its removal.

– Topsoil and subsoil will be replaced in the reverse order to its removal.

– Topsoil will be respread in a depth of 50 to 100 mm, followed by contour furrowing or ripping to allow for infiltration of rainfall, some mixing of subsoil and topsoil and to loosen the soil surface for sowing or planting tube stock if required.

– Ripping will be carried out prior to the wet season (i.e., October-November) to prepare the soil for wet season rains, should they happen.

Revegetation from Physical Preparation and Planting

Revegetation from physical preparation will include the selection of seed and plant species mix, planting methods, timing, weed control, and monitoring and maintenance. This is discussed in more detail below.

Species Selection–the species seed mix and planting densities for revegetation (along with fertiliser requirements) in disturbed areas will be determined in consultation with relevant experts, the Traditional Owners and DNRETAS. Species will be of local provenance (i.e., seed collected from species on site) such as Chrysopogon fallax (Golden Beard Grass) and Acacia hilliana (Flying-saucer Bush); other potential shrub and tree species for revegetation are detailed in Appendix B.

Planting Methods – consideration will be given to the appropriate use of the following planting methods:

• Seed broadcasting. • Direct seeding. • Spreading of seed-bearing slash (especially for eucalypt and acacia species). • Nursery-grown tube stock.

The planting of tube stock will be considered where the rapid establishment of native vegetation is required, such as along drainage lines. However, this may not be practical or feasible if climatic conditions do not favour the successful growth of these plants.

Timing–revegetation will be undertaken in October and November where possible, prior to wet season rains to stimulate the growth of seed shed during the dry season. Revegetation undertaken at this time will also ensure that wet season rains in the following year, should they occur, provide adequate moisture for maximum seedling survival and growth.

Weed Control–areas progressively rehabilitated will be carefully monitored for evidence of the introduction and establishment of weeds, with the objective of identifying and treating them before they become persistent. No weed species declared under the Weeds Management Act are known to occur within the Mineral Lease. Environmental weeds known to be present in the project area are buffel grass (Cenchrus ciliaris) and kapok bush (Aerva javanica). Weeds known to be in the region include:

• Bellyache bush (Jatropha gossypifolia).


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• Mesquite (Prosopis limensis). • Noogoora burr (Xanthium strumarium). • Paddy’s lucerne (Sida rhombifolia). • Parkinsonia (Parkinsonia aculeata).

Where weeds have become established in progressively rehabilitated areas, appropriate weed control measures will be undertaken. These will include:

• Hand-pulling. • Spraying of weeds with an appropriate herbicide.

8.1.4 Monitoring and Maintenance

Methods to monitor and maintain progressively rehabilitated and revegetated areas will include:

• Establishing 360°-photo-monitoring points throughout the project area.

• Conducting surveys to monitor the success rate of seedling emergence and survival, weed invasion, browsing levels (i.e., animal attack of regenerating vegetation) and erosion, using the photo monitoring points to track progress.

Where monitoring has identified erosion, weed invasion, failure of revegetation (to any material degree) or excessive browser damage to regenerating vegetation, maintenance activities will be implemented. These may include:

• Repairing eroded areas. • Weed control using chemical, mechanical and/or manual methods. • Pest control (e.g., baiting). • Infill planting. • Spot sowing. • Reseeding.

A database that summarises disturbed areas and their rehabilitation will be established.

8.2 Final Decommissioning

Final decommissioning and rehabilitation activities will be associated with the:

• Removal of all infrastructure no longer required at the site. • Final site tidy up. • Assessment, and if needed, remediation, of contaminated sites. • Ongoing monitoring and assessment of post-closure rehabilitation.

A final decommissioning plan will be developed in consultation with regulatory authorities during operations and as part of the closure process. This plan will further detail completion criteria and refine the timeline for decommissioning and determination of compliance with regulatory authority requirements.

The proposed process for the final decommissioning for each of the domains is discussed below. This is a conceptual process at this stage; it will be refined during closure planning during the life of the mine.


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8.2.1 Site Infrastructure

In general the process for final decommissioning of site infrastructure will be as follows:

• Infrastructure will be removed from site, provided to Traditional Owners and/or sold.

• Contaminated material will be remediated, and if necessary, removed and disposed of at an appropriate registered facility.

• Concrete pads will be broken up and either disposed of on site, used as clean landfill in areas of existing disturbance where the landform is amenable to filing, or transported off site for disposal in an appropriate clean fill facility.

• Large concrete footings and foundations will be made safe and buried in situ.

• Topsoil will be spread.

• The area will be ripped and seeded.

Further description of final decommissioning for infrastructure is given below where it differs from that described above.

Aerodrome

On completion of the project the airstrip will be left on site for use by the landowners. However, any ancillary infrastructure, such as lighting and refuelling equipment, will be removed and may be sold.

Borefields

Some bores, such as those in the Arruwurra and northern borefield area, may be left in place to provide an additional reliable source of water to the Wunara community and Dalmore Downs. However, most bores will be decommissioned in accordance with Northern Territory Government guidelines (e.g., DRDPIFR, 2007B).

Main Workshop and Stores Area

Contaminated concrete, e.g., concrete contaminated with hydrocarbons, will be cleaned on site and disposed at an appropriate registered facility or, if appropriate, used as backfill.

8.2.2 Extractive Workings

Borrow pits will be contoured to provide safe batters for fauna and public, while also minimising the potential for being long-term mosquito breeding grounds. They will then be revegetated with native plant species of local provenance.


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8.2.3 Hard Rock Pits

Twenty three open pits will be developed as part of the project; 4 in the Arruwurra deposit and 19 in the Main Zone deposit (Figure 5.2 and Figure 5.3, respectively). In both the deposits some pits will be progressively backfilled and rehabilitated after the year of completion (see Section 8.1.2).

The end land use for the completely backfilled pit areas (two pits) will be a modified landform with landscape function and vegetation that is resilient, self-sustaining and comparable to surrounding area. For those not completely backfilled (21 pits) a void will remain, it is unlikely that over time these will fill and become permanent water bodies. Due to the fact that annual evaporation is far greater than rainfall in the region, in addition the pit catchments will in effect be only the area of their voids and as such very little rainfall will collect in the pits. Around the voids a permanent abandonment bund will be constructed to prevent public access. This bund will prevent public vehicle access to the pits and will be constructed of suitable material to do so. The distance from the void will be determined in accordance with Western Australian guidelines for unweathered rock (DIR, 1997). Therefore, the abandonment bund will have a minimum height of 2 m and a minimum base width of 5 m, and will be located a distance from the void where an angle of 25° projected from the toe of the pit wall intercepts the surface plus an additional 10 m buffer zone (see Figure 8.4). Where possible, the abandonment bund will be located on already disturbed land (e.g., haul roads).

8.2.4 Water Dams and Ponds

Major surface water management structures will primarily comprise sedimentation ponds and drains.

Following closure, residue material in the ponds will be analysed to determine contaminant concentrations. All pipework and infrastructure will be removed.

Immediately following closure it is likely that these surface water management structures will continue to be required to capture any sediment from the recently rehabilitated areas and demonstrate that water quality objectives have been achieved.

Surface water management structures such as sediment ponds and drains established during operations will be retained post-closure. The reasons for this are:

• Surface drainage established during operations will be complete and stable.

• Clean water will remain separated from water draining areas of disturbance.

• Although vegetation will establish, sediment ponds will continue to provide a final filter for runoff from the rehabilitated site.

• These areas may have been colonised by fauna, thereby creating new habitat areas.


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8.2.5 Waste Rock Storages

The foremost rehabilitation outcome for the waste rock storages will be to ensure that the final landform will be stable (physically and chemically). Other desired outcomes for the waste rock storage areas will be that their landscape function and vegetation is resilient, self-sustaining and comparable to the surrounding areas.

There will be a total of 17 waste rock storages; 3 for the Arruwurra deposit and 14 for the Main Zone deposit (Figures 5.2 and 5.3, respectively). The waste rock storages will be 20 m high; their footprints and years of completion are detailed in Table 8.2. Following their year of completion it is anticipated that the waste rock storages will be rehabilitated, thereby allowing progressive rehabilitation of nine waste rock storages.

Table 8.2 Waste rock storage details

Storage Footprint (ha) Year Completed

Arruwurra

AS 1 168 2013

AS 2 41 2013

AS 3 21 2011

Main Zone

MZS 1 250 2019

MZS 2 31 2019

MZS 3 61 2019

MZS 4 59 2019

MZS 5 61 2019

MZS 6 78 2018

MZS 7 45 2018

MZS 8 41 2015

MZS 9 90 2017

MZS 10 160 2018

MZS 11 35 2017

MZS 12 40 2015

MZS 13 42 2015

MZS 14 153 2015

The waste rock storages are designed to a maximum height of 20 m above the natural ground level. Lower elevations for these waste rock storages were considered; however, reducing the elevation significantly increases the disturbance area. As such, a 20 m elevation was considered an appropriate compromise between disturbance area and visual/landscape impact.

Geochemical assessment of the waste rock has indicated that the potential for acid forming material is negligible. The lack of potentially acid forming (PAF) material means the waste rock storages will not require a detailed engineered cover system. Therefore, closure of the waste rock storage areas will be accomplished by carrying out a geotechnical investigation to ensure that the storage areas are stable. They will then be


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contoured and revegetated to establish self-sustaining natural vegetation of local provenance. Progressive revegetation undertaken during mine life will guide the revegetation technique to be used to cover the final waste rock storage areas.

8.2.6 Exploration

Drillholes, Pads, Sumps and Costeans

All exploration areas will be rehabilitated and revegetated to establish landscape function and vegetation that is resilient, self-sustaining and comparable to surrounding areas. To accomplish this, drill holes, costeans or bulk sample pits and drill pads will be rehabilitated according to Northern Territory Government guidelines (e.g., DRDPIFR 2007B, 2007C, 2007D).

Tracks and Gridlines

All exploration tracks and gridlines will be rehabilitated in accordance with Northern Territory Government guidelines (e.g., DRDPIFR, 2007E). The objective will be to provide landscape function and vegetation that is resilient, self-sustaining and comparable to surrounding area.

8.2.7 Access and Haul Roads

Access Roads

The main site access road will be left in place, albeit in a reduced capacity, following rehabilitation to a single track. This will ensure access to the site for ongoing monitoring while discouraging public access. Other access and haul roads will be rehabilitated and revegetated to provide landscape function and vegetation that is resilient, self-sustaining and comparable to surrounding area.

Haul Roads

Where not left to provide access for Traditional Owners, haul roads will be rehabilitated and revegetated to provide landscape function and vegetation that is resilient, self-sustaining and comparable to surrounding area.

8.3 Provision for Care and Maintenance

In the unlikely event that Minemakers is required to place the project into care and maintenance, Minemakers will ensure the following:

• All pits, waste rock storages and ore stockpiles are stabilised.

• All surface water management structures are complete and functioning to control surface water run-off.

• All infrastructure is left in a safe and stable manner.

• Provision is made to continue environmental monitoring during the care and maintenance period.


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9. RISK ANALYSIS

This chapter contains a residual risk assessment for the proposed closure outcomes detailed in Table 7.1. The residual risk assessment considers what the remaining risk is once the proposed closure processes have been effectively implemented.

The risk assessment was conducted by examining the potential consequences (i.e., a measure of severity of impact) and the likelihood that those impacts will occur. The assessment of ‘likelihood’ applied specifically to the resulting impact. Often a final environmental impact results from a chain of events, each with an associated likelihood. These ‘conditional likelihoods’ were considered when determining the final likelihood of the environmental impact occurring.

As part of the risk assessment process, a number of risk management assessment processes were considered. These included the Australian/New Zealand Standard Risk Management (AS/NZS 4360:2004) (Standards Australia, 2004)) and the associated guidelines (HB 436:2004 (Standards Australia, 2004)) and HB 158-2006 (Standards Australia, 2006B)), Standards Australia’s Environmental risk management – Principles and process (HB 203:2006) (Standards Australia, 2006A)) and the United States Environmental Protection Agency’s Guidelines for Ecological Risk Assessment (US Environmental Protection Agency, 1998)).

The descriptors used in this assessment are based on those used in the Standards Australia’s HB 203:2006 (Standards Australia, 2006A) and the South Australian Guidelines for miners: ‘Preparation of a mining lease proposal or mining and rehabilitation program (MARP) in South Australia’ (PIRSA, 2009). These descriptors were chosen as they were considered to be most appropriate for the mining project (Table 9.1).

Table 9.1 Descriptors used to classify likelihood and consequence

Descriptor Definition

Likelihood

Almost certain Is expected to occur in most circumstances, or is of a continuous nature, or likelihood is unknown.

Likely Will probably occur during mine lifetime.

Possible Could occur in most mines.

Unlikely Could occur in some mines, but not expected to occur.

Rare Occurs only in exceptional circumstances.

Consequence

Catastrophic Health – death or widespread health effects, or toxic release off-site with detrimental effect. Environmental – extreme permanent changes to the natural environment (not able to be practically or significantly rehabilitated or alleviated). Social – major public outrage. Financial – huge financial loss (greater than A$500 million). Or the consequences are unknown.


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Table 9.1 Descriptors used to classify likelihood and consequence (cont’d)

Descriptor Definition

Consequence (cont’d)

Major Health – extensive injuries. Environmental – substantial and significant changes to the natural environment or only partially able to be rehabilitated or alleviated. Social – will attract public concern in wider community. Financial – major financial loss (A$100 to 500 million). Or changes will be substantial if cumulative effects are considered.

Moderate Health – medical treatment required. Environmental – significant local changes, but can be rehabilitated or alleviated with difficulty at significant cost and with outside assistance. Social – will attract concern of adjoining community. Financial – high financial loss (A$10 to 100 million).

Minor Health – first aid treatment required. Environmental – on-site release immediately contained very local consequence with no significant long-term changes or may be simply rehabilitated. Social – not of significant concern to wider community. Financial – medium financial loss (A$1 to 10 million).

Insignificant Health – no injuries. Environmental – negligible environmental impact. Social – unlikely to be noticed by public. Financial – low financial loss (less than A$1 million).

The level of risk for each potential impact is then determined by combining consequences and likelihood using the risk matrix shown in Table 9.2.

Table 9.2 Qualitative risk analysis matrix

Severity of Consequence

Catastrophic Major Moderate Minor Insignificant

Almost Certain

Extreme Extreme Extreme High High

Likely Extreme Extreme High High Moderate Possible Extreme Extreme High Moderate Low Unlikely Extreme High Moderate Low Low

Likelihood of Consequence

Rare High High Moderate Low Low

The evaluation of residual risks is based on the findings from specific investigations carried out in support of the EIS, knowledge of the existing environment likely to be affected, experience at similar operations elsewhere and professional judgement. It is expected that Minemakers will manage all residual risks to ‘as low as reasonably practicable’ (ALARP).

Table 9.3 summarises the residual risks associated with not meeting the stated closure outcomes for each domain. The likelihood and consequence of the residual impacts have been considered after the implementation of the proposed closure processes.

A brief discussion of each of the risk assessments and outcomes is provided in the corresponding section below.


Table 9.3 Residual risks for each domain

Domain Impact Likelihood Consequence Residual Risk

General

All site components

The community and future generations are left with residual liability for site rehabilitation or maintenance.

Unlikely Moderate Moderate

Public health and safety is not ensured Rare Major High

Landscape function and vegetation is not resilient, self sustaining and comparable to the surrounding areas.


Long term contamination of land. Unlikely Minor Low

The community is unaware of mine closure concept and timing. Rare Major High

Infrastructure is not removed. Rare Minor Low

Site infrastructure

Borefield Uncontrolled release of groundwater and adverse change in ecological conditions as a result of bores not being appropriately decommissioned.

Rare Insignificant Low

Extractive Workings and Hard rock pits (Arruwurra and Main Zone)

Backfilled pits Landscape function and vegetation is not resilient, self sustaining and not comparable to the surrounding areas.

Unlikely Major High

Open pits Injuries or deaths resulting from pit stability or ease of access to pit. Rare Catastrophic High


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Table 9.3 Residual risks for each domain (cont’d)

Domain Impact Likelihood Consequence Residual Risk



Surface water management structures remaining in place are not physically stable and safe to fauna and humans.


Storages and waste rock storages

Waste rock storages Waste rock storages not physically or chemically stable. Unlikely Major High

Self-sustaining vegetation is not established over waste rock storage areas. Unlikely Major High

Decrease in visual amenity of landform compared to baseline. Likely Insignificant Moderate

Exploration


Injury due to inadequate rehabilitation. Rare Moderate Moderate

Landscape function and vegetation is not resilient, self sustaining and comparable to the surrounding areas.

Rare Minor Low

Tracks and gridlines Landscape function and vegetation is not resilient, self sustaining and comparable to the surrounding areas.

Rare Minor Low


Access roads Landscape function and vegetation is not resilient, self sustaining and comparable to the surrounding areas.

Rare Minor Low

Haul roads


9.1 General

This section discussed residual risks considered to be generic to the project.

The Community and Future Generations are Left with Residual Liability for Site Rehabilitation and Maintenance

Should Minemakers not complete the mine closure and rehabilitation process the liability for this may pass to the Northern Territory Government to provide rehabilitation or take steps to mitigate closure problems. The large financial liability for the Northern Territory Government is considered a moderate consequence. However, as per the standard condition of operation for all mine operators in the Northern Territory, Minemakers will lodge a bond with the Northern Territory Government on an annual basis that will cover the full cost of rehabilitation of the site by a third party, taking into account any progressive rehabilitation completed. Therefore, it is considered unlikely that this impact will result. The residual risk is moderate.

Public Health and Safety is not Ensured

There is the potential for members of the public to enter the site and be exposed to situations that could result in injury, e.g., falling into the pit voids. Therefore, it is considered of major consequence if this were to occur. However, Minemakers will remove potential dangerous infrastructure from the site (e.g., the mobile crushing and screening plants) and stabilise potentially dangerous structures (e.g., waste rock storages). Also, Minemakers will endeavour to restrict public access to site by obstructing or concealing the access road and constructing bunds around the pits, hence it is considered very unlikely (rare) that public safety will be endangered. The residual risk is high.

Ecosystem and Landscape Function is not Resilient, Self-sustaining or Comparable to the Surrounding Areas

The project area is relatively undisturbed. Minemakers will be undertaking progressive rehabilitation and active revegetation of the site and will have opportunity to refine revegetation techniques during its operations. It is considered unlikely that the desired landscape function and vegetation will not be achieved. The consequence of not achieving this outcome is moderate as it will require significant cost and assistance to return to the site and rehabilitate it so the ecosystem and landscape function is achieved. The residual risk is moderate.

Long Term Contamination of Land

Contamination of land will be minimised during operations through measures such as design of facility, operating practices and spill response and remediation procedures. It is therefore unlikely that contamination of the site will occur that is not remediated during operations. At the cessation of mining and processing activities a contamination assessment and any consequently required remedial actions will be undertaken as part of the decommissioning activities. At mine closure it is unlikely that any residual contamination as a result of mining activities will exist. If this was to occur the consequence could be minor as there would be some financial loss as a consequence of the costs of remediation. The residual risk is low.


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The Community is Unaware of Mine Closure Concept and Timing

It is important that the community be aware of the mine closure concept and the timing of closure, so it can plan and prepare for this time. If this does not occur the consequences may be major with significant socio-economic impacts, such as unexpected loss of community support or unexpected population decline. Minemakers has already demonstrated its commitment to community engagement through the planning and assessment phase of the project and will maintain this throughout operations. It is therefore considered rare that the community will not be fully aware of the mine closure concept and timing. The residual risk is high.

Infrastructure is not Removed.

Removal of all mine site infrastructure is planned and budgeted for as part of the decommissioning activities. It is a straightforward task that is likely to involve the company getting a return on some assets. It is considered very unlikely (rare) that the infrastructure will remain on site. If the administration offices were not removed the consequence would be minor as it could be easily rectified. The residual risk is low.

9.2 Site Infrastructure

9.2.1 Borefield

Uncontrolled Release of Groundwater and Adverse Change in Ecological Conditions as a Result of Bores not Being Appropriately Decommissioned

Decommissioning and capping of the borefield will be undertaken in accordance with all relevant Australian and Northern Territory standards. In addition, upon mine closure, an audit of the domain will ensure this is the case. It is considered very unlikely (rare) that uncontrolled release of groundwater and the subsequent ecological changes will occur. However, if it does the consequences will be insignificant because the uncontrolled release of groundwater may be rectified with limited financial loss and the ecological changes will largely cease with the water supply being stopped and appropriate management measures (e.g., weed and pest control) being implemented. The residual risk is low.

9.3 Backfilled Pits

Landscape Function and Vegetation is not Resilient, Self Sustaining and Comparable to the Surrounding Areas

It is unlikely that a self-sustaining vegetation cover will not be achieved since revegetation techniques will be revised during the progressive rehabilitation and the final revegetation activities will be based on the most successful of these.

If a self-sustaining vegetation cover was not established over the backfilled pits the consequence will be major as it may cause instability and large scale erosion during the wet season, thereby limiting landscape function and reducing visual amenity. The residual risk is high.


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9.4 Open Pits

Injuries or Deaths Resulting from Pit Stability or Ease of Access to Pit

A pit bund will be constructed around each pit at closure to prevent vehicle access and discourage the general public access to the pit. The bund will be constructed at least 25 m beyond the open pit void. Due to these measures it is considered rare that there would be any injuries or deaths due to pit stability or ease of access to the pit. The consequence of this impact occurring will be catastrophic if it resulted in a death or serious injury. The residual risk is high.

9.5 Water Dams and Ponds

Surface Water Structures Remaining in Place are not Physically Stable and Safe to Fauna and Humans

The surface water structures that are planned to remain in place after closure are most likely to be surface water retention ponds. These structures will be shaped to allow the safe ingress and egress of fauna and people. The stability of the structures will be surveyed during site decommissioning to confirm that the structures are still sound. Due to these measures it is considered unlikely that there will be any stability or safety issues associated with the surface water structures. The consequence of this impact occurring will be moderate and will require remedial action. The residual risk is therefore moderate.

9.6 Waste Rock Storages

Waste Rock Storages are not Physically or Chemically Stable

The waste rock storage areas will be the most significant closure feature within the landscape. If these are physically unstable it may present a safety risk and also cause environmental impacts (e.g., sedimentation of downstream waterways). If the waste rock storage areas are chemically unstable, land and water contamination may occur.

Instability of the areas will be of public concern and rehabilitation of the landform post-closure may be difficult and expensive. Therefore, the consequences of the landform being physically or chemically unstable are considered to be major; however, it is unlikely this will occur as Minemakers has a sound understanding of the geotechnical and geochemical composition of the materials and this is not expected to be problematic. The residual risk, however, remains high.

Self-sustaining Vegetation is not Established over Waste Rock Storages

It is unlikely that a self-sustaining vegetation cover will not be achieved since revegetation techniques will be refined during the progressive rehabilitation to determine the most suitable method for use during final rehabilitation. If a self-sustaining vegetation cover is not established over the waste rock storages the consequence will be major as it may cause instability and large scale erosion during the wet season; it may also reduce the visual amenity and habitat function of these areas. The residual risk is high.


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Decrease in Visual Amenity of Landform Compared to Baseline

Topography in the project is currently flat to gently undulating, the waste rock dumps for the project will rise above the current landform to a height around 20 m, and as such will represent a significant and noticeable change. However, the area is sparsely populated and the closest local population, the Wunara community, will be made well aware of the changes prior to the project commencing. In addition, the users of the Barkly Highway will also be able to clearly see the waste rock storages at the Main Zone due to their proximity to the road. Therefore, it is likely that some impact to visual amenity will occur as a result of constructing the waste rock storage areas; they will represent large mounds in an otherwise unremarkable landscape. Despite this, the consequence of this impact is considered insignificant because the waste rock storage areas will be contoured to blend in with the surrounding landscape as much as possible, as well as revegetated. The residual risk is moderate.

9.7 Exploration

9.7.1 Drillholes, Pads, Sumps and Costeans

Injuries due to Inadequate Rehabilitation

All drillholes, pads, costeans and sumps will be backfilled; due to these measures it is considered rare that there will be any injuries or deaths due to the drillholes, pads, costeans and sumps. The consequence of this impact occurring will be moderate if it resulted in a serious injury; death is unlikely. The residual risk is therefore moderate.

Landscape Function and Vegetation is not Resilient, Self Sustaining and Comparable to the Surrounding Areas

Rehabilitation of drillholes, pads, sumps and costeans is planned and budgeted for as part of the decommissioning activities, in addition progressive rehabilitation over mine life will have identified the most successful revegetation and rehabilitation techniques. It is considered very unlikely (rare) that landscape function and vegetation will not be resilient, self sustaining and comparable to the surrounding areas. If this did not occur the consequence would be minor. The residual risk is low.

9.7.2 Tracks and Gridlines

Landscape Function and Vegetation is not Resilient, Self Sustaining and Comparable to the Surrounding Areas.

Rehabilitation of tracks and gridlines is planned and budgeted for as part of the decommissioning activities, in addition progressive rehabilitation over mine life will have identified the most successful revegetation and rehabilitation techniques. It is considered very unlikely (rare) that landscape function and vegetation will not be resilient, self sustaining and comparable to the surrounding areas. If this did not occur the consequence would be minor. The residual risk is low.


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9.8 Access and Haul Roads

Landscape Function and Vegetation is not Resilient, Self Sustaining and Comparable to the Surrounding Areas.

Rehabilitation of access roads and haul roads is planned and budgeted for as part of the decommissioning activities, in addition progressive rehabilitation over mine life will have identified the most successful revegetation and rehabilitation techniques. It is considered very unlikely (rare) that landscape function and vegetation will not be resilient, self sustaining and comparable to the surrounding areas. If this did not occur the consequence would be minor. The residual risk is low.


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10. POST CLOSURE MONITORING AND MAINTENANCE

10.1 Post-closure Monitoring

The high-level environmental and social monitoring program proposed to be implemented after the closure of the project is summarised in Table 10.1. It is recommended this program be periodically reviewed in accordance with the Mining Management Plan (MMP) reporting schedule and to incorporate any monitoring requirements determined as conditions of approval for the project.

10.2 Maintenance

Following rehabilitation of the site there will be a requirement for maintenance, particularly during the initial one to two years following closure. These activities are likely to involve repair to surface water drainage structures, repair of any erosion areas or the reseeding of areas due to poor vegetation establishment. More specifically, where monitoring has identified erosion, weed invasion, failure of revegetation (to any material degree) or excessive browser damage to regenerating vegetation, maintenance activities will be implemented to ensure regeneration progresses successfully and rapidly. These may include:

• Repairing eroded areas. • Weed control (chemical, mechanical and manual methods). • Pest control (baiting, fencing, etc.). • Infill planting. • Spot sowing. • Reseeding.

Maintenance of the site will continue until all lease conditions and completion criteria have been met.


Table 10.1 Summary of proposed environmental and social monitoring program

Location Frequency Parameters Compliance Criteria

Land Uses

Project area soil monitoring locations1 and any spill locations

At end of decommissioning. • Metals.

• Nutrients.

• Hydrocarbons.

• No increase in soil contamination levels as a result of mining activities.

See also surface water and groundwater monitoring below

Surface Water – Water Quality

Mineral Lease area and downstream

At the start and end of the wet season for two years post closure if compliance criteria are being met. If criteria are not being met monitoring should continue to occur until two consecutive sampling events show criteria being met.

• pH, conductivity, turbidity, TSS.

• Metals, major ions and nutrients (selected samples).

• Alkalinity and dissolved oxygen (selected samples).

• Concentrations of contaminants in specified surface waters are consistent with baseline concentrations (as determined by rainfall event driven surface water quality monitoring).

Mineral Lease area drainage lines

Quarterly for one year post closure if compliance criteria are being met. If criteria not being met monitoring should continue until two consecutive inspections show criteria being met.

• Visual evidence of erosion.

• Visual evidence of condition.

• Structures operating effectively and not damaged.

• No erosion issues.

Surface Water – Stream Sediment Quality

Mineral Lease area and downstream

Six monthly for two years post closure if compliance criteria are being met. If criteria are not being met monitoring should continue to occur six monthly until two consecutive sampling events show criteria being met.

• Total and dilute acid extractable metals (<2000 µm).

• Particle size distribution.

• Contaminants in bed sediments are within 10% of the background concentrations in specified stream bed channels (as determined by the monitoring).

1 Soil monitoring locations to be determined, locations will include two sites in each of the closure domains.


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Table 10.1 Summary of proposed environmental and social monitoring program (cont’d)

Location Frequency Parameters Compliance Criteria Groundwater – Regional

Six monthly for two years post closure if compliance criteria are being met. If criteria are not being met monitoring should continue to occur six monthly until two consecutive sampling events show criteria being met.

• Water levels. • pH, conductivity. • Usage (volume pumped).

Selected local wells on neighbouring properties

Annually for two years post closure if compliance criteria are being met.

• Metals, major ions and nutrients.

• Water quantity available not impacted by mine drawdown.

• No reduction in water quality compared to baseline.

Air Quality1 Four to six locations within (or close to) the project area

Quarterly for two years post closure if compliance criteria are being met. If criteria are not being met monitoring should continue to occur until two consecutive sampling events show criteria being met.

• Total dust deposition.

• Average background levels.

Flora Project area, selected sites

At closure and annually after wet season for two years post closure if compliance criteria are being met (success likely to be influenced by rainfall). If criteria not being met monitoring should continue until inspections show criteria being met.

• Health of vegetation community in terms of structure, disturbance, weeds and litter.

• Rehabilitation progressing as planned and demonstrates signs of meeting the final closure criteria.

• Photographic monitoring of vegetation. • No significant impact compared to baseline. Flora – Pest Plants Project area At closure and twice a year after wet

season for two years post closure if compliance criteria are being met (success likely to be influenced by rainfall). If criteria not being met monitoring should continue until inspections show criteria being met.

• Weed outbreaks (including size and number of infestations) and weed control treatment.

• No increase in weed density or distribution and no introduction of new declared weeds (when compared to control sites or baseline data).

1 Air quality monitoring sites to be established in consultation with DNRETAS.


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Table 10.1 Summary of environmental and social monitoring program (cont’d)

Location Frequency Parameters Compliance Criteria

Fauna

At closure and annually after wet season for two years post closure if compliance criteria are being met. If criteria not being met monitoring should continue until inspections show criteria being met.

• Fauna species in each of the key habitat types.

• No significant adverse impact when compared to baseline.

Project area

At closure and quarterly for two years post closure if compliance criteria are being met. If criteria not being met monitoring should continue until inspections show criteria being met.

• Pest animals and pest animal control success.

• No increase in abundance of pest (feral) species when compared to control sites or baseline data.

Indigenous Cultural Heritage

Identified Indigenous sites within Mineral Lease area, if found

At closure to confirm compliance with criteria.

• Preservation and integrity of identified cultural heritage material.

• No unauthorised disturbance to sites.

Identified Indigenous sites outside Mineral Lease area, if identified

At closure to confirm compliance with criteria.

• Preservation and integrity of sacred sites. • No unauthorised disturbance to sites.


11. FINANCIAL PROVISION FOR CLOSURE

11.1 Cost Estimate

The cost estimate for rehabilitation of the site has been prepared using the draft Mines and Energy Security Calculation Form (DRDPIFR, 2009). The cost estimate is based on the assumption that a third party undertakes the rehabilitation and decommissioning works at the end of mine life and that there is no revenue from resaleable items. It assumes a worst case scenario, i.e., that the total final disturbance area of the project undergoes no progressive rehabilitation during the life of the project. In reality, the actual closure liability at any stage of the project is likely to be significantly lower than this estimate.

The estimated cost (Table 11.1) is $43.5 million; the full spreadsheet used to calculate the costs is provided in Appendix C.

Table 11.1 Summary of estimated closure costs

Domain Estimated Cost ($AUD)

Site Infrastructure $2,436,231.00 Extractive Workings $368,890.00 Hard Rock Pits $28,303,722.00 Water Dams and Ponds $12,540.00 Waste Rock Storages $2,367,500.00 Exploration $2,183,800.00 Access and haul road $1,851,120.00 Sub total (domains and other sundry items) $37,523,803

Post closure monitoring $187,495.21 Contingency (5%) $5,656,694.73 Total (nearest $500,000) $43,500,000

11.2 Funding of Security Payment

Minemakers will lodge the security payment to such an amount of the surety as determined annually by the Minister, to cover the full cost of rehabilitation liability assessed by an independent third party at any time. Minemakers will meet all charges and costs in obtaining and maintaining the security payment.

Minemakers will provide an independent audit of the achievement of the completion criteria, to be carried out by an independent auditor approved by the Minister.


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11.3 Public Liability Insurance

Minemakers will, prior to commencing operations and for the duration of the lease, maintain public liability insurance to cover all operations under the Mineral Lease (including sudden and accidental pollution) for a sum not less than $20 million or such greater sum as specified by the Chief Inspector of Mines, and make such amendments to the terms and conditions of the insurance as the Chief Inspector of Mines may require.

11.4 Financial Provision

Financial provision for mine rehabilitation and closure activities will be lodged with DRDPIFR. These provisions will be made in accordance with the Australian equivalents of the International Accounting Standards. The real cost of closure relating to the actual area disturbed will be regularly reviewed and provided for in the projects operating costs.


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12. SCHEDULE

The progress of closure planning (including progressive rehabilitation) will be reported on an annual basis as part of the operation’s annual Mining Management Plan. A conceptual closure timeline for the project is shown in Table 12.1, where Year 1 corresponds to the commencement of mining.

Table 12.1 Schedule for rehabilitation of each domain

Year Domain

1 2 3 4 5 6 7 8 9 10 11 12

Site infrastructure

Accommodation camp

Administration offices

Airstrip

Borefields

Crushing and screening plant


Power station

Extractive workings

Borrow pits

Hard rock pits


Surface water retention ponds

Waste rock stockpiles

Exploration


Access tracks and gridlines


Access road

Haul roads

Monitoring


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13. REFERENCES

AKD. 2005. Wonarah phosphate deposit Northern Territory. February. Report prepared by AKD Ltd, West Perth, Western Australia.

ANZMEC and MCA, 2000. Strategic Framework for Mine Closure. Australian and New Zealand Minerals and Energy Council and Minerals Council of Australia.

BOM. 2009. Bureau of Meteorology: weatherstation data. A www publication accessed on 9 April 2009 at http://www.bom.gov.au/climate/data/weather-data.shtml.

CNS.2009. Wonarah Phosphate Project EIS. Report prepared by Coffey Natural Systems for Minemakers Pty Ltd. Coffey Natural Systems, Darwin, Northern Territory.

DEH. 1998. Landform Design and Rehabilitation. Best Practice Environmental Management in Mining. Department of the Environment and Heritage. May 1998.

DIR, 1997. Safety Bund Walls Around Open Pit Mines: Guideline. Document Number: ZMA048HA. Western Australian Department of Industry and Resources. December 1997.

DITR. 2006. The Leading Practice Sustainable Development Program for the Mining Industry - Mine Closure and Completion guidelines. October. Department of Industry, Tourism and Resources.

DITR. 2007. The Leading Practice Sustainable Development Program for the Mining Industry – Biodiversity Management guidelines. February. Department of Industry, Tourism and Resources.

DITR. 2007. The Leading Practice Sustainable Development Program for the Mining Industry – Mine Rehabilitation guidelines. October. Department of Industry, Tourism and Resources.

DITR. 2007. The Leading Practice Sustainable Development Program for the Mining Industry - Managing Acid and Metalliferous Drainage guidelines. October. Department of Industry, Tourism and Resources.

DITR. 2007. The Leading Practice Sustainable Development Program for the Mining Industry - Stewardship guidelines. October. Department of Industry, Tourism and Resources.

DITR. 2007. The Leading Practice Sustainable Development Program for the Mining Industry – Community engagement and development guidelines. October. Department of Industry, Tourism and Resources.

DRDPIFR. 2007A. Advisory Note AA7-013. Security Calculation Procedure. November. Northern Territory Department of Regional Development, Primary Industry, Fisheries and Resources.

DRDPFR. 2007B. Advisory Note AA7-008. Capping and Plugging of Exploration Drillholes and Abandonment of Bores. August. Northern Territory Department of Regional Development, Primary Industry, Fisheries and Resources.

DRDPIFR. 2007C. Advisory Note AA7-007. Construction and Rehabilitation of Drill Pads and Benches. August. Northern Territory Department of Regional Development, Primary Industry, Fisheries and Resources.

DRDPIFR. 2007D. Advisory Note AA7-006. Construction and Restoration of Costeans and Bulk Sample Pits. August. Northern Territory Department of Regional Development, Primary Industry, Fisheries and Resources.


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DRDPIFR.2007E. Advisory Note AA7-005. Clearing and Rehabilitation of Grid Lines and Tracks, August. Northern Territory Department of Regional Development, Primary Industry, Fisheries and Resources.

DRDPIFR. 2009. Mines and Energy Security Calculation Form. Northern Territory Department of Regional Development, Primary Industry, Fisheries and Mines.

Edgoose, C. J. 2003. Barkly Tableland region, Northern Territory. Department of Lands, Planning and Environment, Alice Springs, Northern Territory.

Hackman, D., Teh, M., Chouzadjan, K., and Watkins, R. 2000. Wonarah phosphate project prefeasibility study. January. Internal report prepared by Rio Tinto Technical Services, South Melbourne, Victoria.

LES. 2009. Low Ecological Services. Minemakers Wonarah Phosphate Project. Baseline Flora and Fauna Report. Report prepared for Coffey Natural Systems, Alice Springs, Northern Territory. May.

MCA. 2004, Enduring Value. The Australian Minerals Industry Framework for Sustainable Development. Minerals Council of Australia.

NEPC. 1999. National Environment Protection on Assessment of Site Contamination. National Environment Protection Council.

NTMC. 2004. Team NT: Technologies for the Environmental Enhancement of Mining in the Northern Territory Toolkit. Northern Territory Minerals Council (Inc.) and the Mines and Petroleum Management Division of the Northern Territory Government. Darwin.

PIRSA. 2009. Guidelines for miners: preparation of a mining lease proposal or mining and rehabilitation program (MARP) in South Australia. Version 4.9. Prepared by the Mineral Resources Group, Primary Industries and Resources South Australia.

Standards Australia. 2004. Risk Management AS/NZS 4360:2004. Report prepared by Standards Australia and Standards New Zealand, Sydney, New South Wales.

Standards Australia. 2004. Handbook Risk Management Guidelines Companion to AS/NZS 4360:2004. Report prepared by Standards Australia and Standards New Zealand, Sydney, New South Wales.

Standards Australia. 2006A. HB 203:2006 Environmental risk management – Principles and process. Report prepared by Standards Australia, Sydney, New South Wales.

Standards Australia. 2006B. Handbook Delivering assurance based on AS/NZS 4360:2004 Risk Management. Report prepared by Standards Australia, Sydney, New South Wales.

US Environmental Protection Agency. 1998. Guidelines for Ecological Risk Assessment. US Environmental Protection Agency, Washington, DC, United States of America. A WWW publication accessed online on 10 August 2009 at http://cfpub.epa.gov/ncea/CFM/recordisplay.cfm?deid=12460#Download

Appendix A Community Consultation Summary

Meeting Type Minemakers Reps Organisation Representatives Issues Discussed Commitments Given

Face to face AD, NB, AH Julalikari Remote Employment Services

Trevor Munkton, Colin Nielson, Ken Peats, Tony Miles

Training capacity, rehabilitation services, possible partnership with Group Training NT

To consider JRES as a potential service provider

Face to face NB, PR, Tara Halliday CNS DRDPIFR Gillian Jan, Alan Holland, others Process for grant of Mineral Lease, water search north of highway, MMP requirements and format, security assessment tool, infrastructure required by Traditional Owners to remain at mine closure

Submit MMP in preferred format. Calculate security using departments tool

Telephone call NB DRDPIFR Gillian Jan Annual re‐calculation of bond for forthcoming 12 months work

None

Telephone call NB CLC Julie‐Ann Stoll Arrangements for meeting on 25 September, need for better infrastructureat Wunara Community

Attend meeting on 25 September

Face to face NB, BH, Dan Moriarty CNS Environment Centre NT Dr Stuart Blanch, Melaine Bradley

Project outline, principle environmental investigations and findings, Traditional Owner engagement

Consider ECNT key areas of interest in the EIS

Appendix B Species Selected as Suitable for Revegetation

Land Unit Species Name Common NameAlluvial Low Lying Sand Plain Carissa lanceolata Conkerberry, Conkle Berry, Kungsberry Bush

Chrysopogon fallax Golden Beard Grass, Ribbon Grass, Weeping Grass, Spear GrassCrotalaria medicaginea var. neglecta Clover‐leaf Rattlepod, Trefoil RattlepodCyperus bulbosus Yalka, NutgrassDigitaria brownii Cotton Panic GrassDodonaea coriacea HopbushEhretia saligna

Eragrostis eriopoda Woollybutt Grass, Naked Woollybutt, Wire Wanderrie Grass, Never FailEremophila latrobei Native Fuchsia, Latrobes Desert Fuchsia, Georgina Poison BushEriachne aristidea

Eriachne mucronata Mountain WanderrieEucalyptus chlorophylla Green‐leaf BoxEucalyptus leucophloia Snappy Gum, MigumEucalyptus microtheca CoolibahEucalyptus odontocarpa Sturt Creek MalleeEucalyptus victrix Smooth‐barked Coolibah, Ghost Gum Coolibah, Gum‐barked CoolibahEulalia aurea Silky Browntop, Sugar GrassFimbristylis ammobia

Fimbristylis oxystachya LukarraraGomphrena lanata

Goodenia armitiana Narrow‐leaved GoodeniaGoodenia heterochila Serrated GoodeniaGossypium australe Native Cotton, Tall Desert RoseGrevillea refracta Silver‐leaf GrevilleaGrevillea refracta subsp. refracta Silver‐leaf GrevilleaGrevillea wickhamii Holly‐leaf GrevilleaHakea macrocarpa Flat‐leaved HakeaHibiscus leptocladus Variable‐leaf HibiscusKeraudrenia integrifolia

Keraudrenia nephrosperma

Melaleuca lasiandra Sandhill Tea‐treeMelaleuca viridiflora Green Paperbark, Broad‐leaved Paperbark, Large‐leaved PaperbarkMelhania oblongifolia Velvet HibiscusMirabilia viminalis

Paraneurachne muelleri Spinifex Couch, Northern Mulga GrassPetalostylis cassioides Butterfly Bush, PetalostylisPortulaca filifolia Slender PigweedPsydrax attenuata var. myrmecophila forma myrmecophila

Ptilotus fusiformis Skeleton plantPtilotus polystachyus Long Pussy‐tailsRhynchosia minima Native Pea, RhynchosiaRulingia loxophylla Desert Fire WeedScaevola parvifolia FanflowerSchizachyrium fragile Firegrass, Red Spathe Grass, Small Red‐leafSclerolaena costata

Senna notabilis

Setaria surgens Brown Pigeon GrassSpermacoce dolichosperma

Tephrosia stuartii

Trianthema pilosa

Trianthema triquetra Red SpinachTribulopis angustifolia

Tribulus eichlerianus BindieyeTriodia pungens Soft Spinifex, Gummy SpinifexTriodia schinzii Feathertop SpinifexVentilago viminalis Supplejack, Vine TreeWaltheria indica

Whiteochloa airoides

Yakirra australiensis Desert Flinders GrassZornia albiflora

Calcareous Plain Acacia lysiphloia Turpentine, Turpentine Bush, Turpentine WattleAcacia sericophylla Dogwood, Wirewood

Deep Sand Plain Acacia stipuligera Scrub Wattle, KurapukaAmphipogon caricinus Grey‐beard Grass, Long Grey‐beard GrassAristida contorta Bunched Kerosene Grass, Mulga GrassAristida holathera Erect Kerosene Grass, White Grass, Arrow GrassAtalaya hemiglauca WhitewoodBulbostylis barbata Short‐leaved RushCorchorus sidoides Flannel WeedEragrostis eriopoda Woollybutt Grass, Naked Woollybutt, Wire Wanderrie Grass, Never FailEriachne aristidea Three‐awn WanderrieEucalyptus leucophloia Snappy Gum, MigumEucalyptus odontocarpa Sturt Creek MalleeEucalyptus pachyphylla Red‐bud MalleeEucalyptus victrix Smooth‐barked Coolibah, Ghost Gum Coolibah, Gum‐barked CoolibahFimbristylis ammobia

Fimbristylis oxystachya LukarraraFimbristylis simulans

Gossypium australe Native Cotton, Tall Desert RoseGossypium sturtianum Sturts Desert RoseGrevillea refracta Silver‐leaf GrevilleaGrevillia wickhamii Northern Corkwood, Bootlace Tree, Bull Hakea, Whistling TreeIpomoea costata Bush Potato, Potato Vine, Desert YamMelaleuca lasiandra Sandhill Tea‐treeMelaleuca viridiflora Green Paperbark, Broad‐leaved Paperbark, Large‐leaved PaperbarkPandorea doratoxylon Spearwood, Wonga Vine, SpearbushParaneurachne muelleri Spinifex Couch, Northern Mulga GrassPtilotus fusiformis Skeleton plantPtilotus polystachyus Long Pussy‐tailsSantalum lanceolatum Plumbush, Wild Plum

Land Unit Species Name Common NameScaevola parvifolia FanflowerSchizachyrium fragile Firegrass, Red Spathe Grass, Small Red‐leafSenna notablis Cockroach BushSetaria surgens Brown Pigeon GrassSida filiformis Fire Sida, Fine SidaTriodia pungens Soft Spinifex, Gummy SpinifexTriodia schinzii Feathertop SpinifexVentilago viminalis Supplejack, Vine TreeYakirra australiensis Desert Flinders Grass

Ephemeral Lakes Acacia hilliana

Ironstone Rocky Rise Acacia lysiphloia Turpentine, Turpentine Bush, Turpentine WattleAcacia stipuligera Scrub Wattle, KurapukaAristida holathera Erect Kerosene Grass, White Grass, Arrow GrassBulbostylis barbata Short‐leaved RushCorchorus sidoides Flannel WeedDicrastylis gilesii

Eragrostis cumingii Fairy Grass, Cumings LovegrassEragrostis eriopoda Woollybutt Grass, Naked Woollybutt, Wire Wanderrie Grass, Never FailEucalyptus leucophloia Snappy Gum, MigumEucalyptus odontocarpa Sturt Creek MalleeGoodenia ramelii

Gossypium australe Native Cotton, Tall Desert RoseGrevillea refracta Silver‐leaf GrevilleaGrevillea refracta subsp. refracta Silver‐leaf GrevilleaGrevillea wickhamii Holly‐leaf GrevilleaHakea macrocarpa Flat‐leaved HakeaHaloragis

Ipomoea costata Bush Potato, Potato Vine, Desert YamKeraudrenia integrifolia

Melaleuca viridiflora Green Paperbark, Broad‐leaved Paperbark, Large‐leaved PaperbarkMirbelia viminalis Yellow BroomPortulaca filifolia Slender PigweedPortulaca oleracea Pigweed, Common Purslane, MunyerooPtilotus calostachyus var. calostachyus Weeping Mulla MullaPtilotus fusiformis Skeleton PlantRulingia loxophylla Desert Fire WeedSchizachyrium fragile Firegrass, Red Spathe Grass, Small Red‐leafSenna notablis Cockroach BushSetaria surgens Brown Pigeon GrassSida arenicola

Sida fibulifera Silver Sida, Pin SidaSida filiformis Fire Sida, Fine SidaThemeda triandra Kangaroo GrassTriodia pungens Soft Spinifex,Yakirra australiensis Desert Flinders Grass

Shallow Sand Plain Aristida holathera Erect Kerosene Grass, White Grass, Arrow GrassAtalaya hemiglauca WhitewoodAtriplex elachophylla

Boerhavia coccinea Tar VineCapparis umbonata Northern Wild Orange, Wild Orange, Bush Orange, Native PomegranateCarissa lanceolata Conkerberry, Conkle Berry, Kungsberry BushCrotalaria medicaginea

Dactyloctenium radulans Button Grass, Finger Grass, Toothbrush GrassDigitaria brownii

Enneapogon polyphyllus Woolly Oat‐grass, Oat‐grass, Leafy Nine‐awnEragrostis eriopoda Woollybutt Grass, Naked Woollybutt, Wire Wanderrie Grass, Never FailEremophila latrobei Native Fuchsia, Latrobes Desert Fuchsia, Georgina Poison BushEremophila longifolia Emu Bush, Weeping Emu Bush, Long‐leaved Desert FuchsiaEucalyptus gamophylla Blue Mallee, Twin‐leaved Mallee, Blue‐leaved MalleeEucalyptus microtheca CoolibahEulalia aurea Silky Browntop, Sugar GrassGossypium australe Native Cotton, Tall Desert RoseHeliotropium ovalifolium

Portulaca oleracea Pigweed, Common Purslane, MunyerooPsydrax latifolia Native Currant, Orange BushPtilotus polystachyus Long Pussy‐tailsScaevola amblyanthera

Scaevola ovalifolia Bushy FanflowerSenna artesmisioides ssp. oligophylla

Trianthema pilosa

Triodia intermedia Winged SpinifexAcacia lysiphloia Turpentine, Turpentine Bush, Turpentine WattleAmphipogon caricinus Grey‐beard Grass, Long Grey‐beard GrassAristida holathera Erect Kerosene Grass, White Grass, Arrow GrassBulbostylis barbata Short‐leaved RushCorchorus sidoides Flannel WeedCorymbia opaca BloodwoodEragrostis cumingii Fairy Grass, Cumings LovegrassEragrostis eriopoda Woollybutt Grass, Naked Woollybutt, Wire Wanderrie Grass, Never Fail

Silcrete Rocky Rise Eucalyptus odontocarpa Sturt Creek MalleeEucalyptus pachyphylla Red‐bud MalleeFimbristylis simulans

Goodenia armitiana Narrow‐leaved GoodeniaGoodenia ramelii

Goodenia strangfordii

Gossypium australe Native Cotton, Tall Desert RoseGrevillea dryandri subsp. dryandri Dryanders GrevilleaGrevillea refracta Silver‐leaf GrevilleaHakea lorea Long‐leaf Corkwood, Corkbark TreeHakea macrocarpa Flat‐leaved Hakea

Land Unit Species Name Common NameMelaleuca viridiflora Green Paperbark, Broad‐leaved Paperbark, Large‐leaved PaperbarkParaneurachne muelleri Spinifex Couch, Northern Mulga GrassPetalostylis cassioides Butterfly Bush, PetalostylisPtilotus polystachyus Long Pussy‐tailsSchizachyrium fragile Firegrass, Red Spathe Grass, Small Red‐leafSenna notabilis Cockroach BushSenna venusa Graceful CassiaSetaria surgens Brown Pigeon GrassSida filiformis Fire Sida, Fine SidaSolanum chippendalei Bush Tomato, NgaruTriodia pungens Soft Spinifex, Gummy SpinifexTriodia schinzii Feathertop SpinifexYakirra australiensis Desert Flinders Grass

Appendix C Security Cost Calculation Spreadsheets

The Department of Regional Development, Primary Industry, Fisheries and Resources - Minerals and Energy, are undertaking a review of the cost estimates which are applied by the department to assess security for all Authorised sites within the Northern Territory.

Comment is sought from industry on the draft estimates presented in this document.Comments can be emailed to [email protected] with attention to Christine Fawcett.

The Department will be conducting an information workshop on 13 February 2009 which will include discussion on the cost estimate review.

Pursuant to section 40 of the Mining Management Act, a costing of closure activities must be included in a Mining Management Plan submitted to the Department in support of an application for Authorisation of a site, or submitted in response to changes to operational activities.A security is required under section 43 of the Northern Territory (NT) Mining Management Act to enable the Minister to prevent, minimise or rectify environmental harm resulting from mining activities.

In establishing the security the Department must assume that the operator is unable to complete the works required to close the site and so the site must be managed by the Department using a 'third party'. Hence the cost will be higher for the Department than an operators costs, as the Department would not have access to onsite personnel and equipment. Additional legal and administrative cost would also be incurred by the Department for making a claim on the security held and managing rhe site.

This review considered costs from other states and from industry and also productivity and costs of machinery.

DEPARTMENT OF REGIONAL DEVELOPMENT, PRIMARY INDUSTRY, FISHERIES AND RESOURCES - SECURITY COST ESTIMATE REVIEW

DRAFT DOCUMENT

January 2009

0 10,000

10,000 100,000

100,000 1,000,0001,000,000 10,000,000

10,000,000 +

DEPARTMENT OF REGIONAL DEVELOPMENT,

PRIMARY INDUSTRY, FISHERIES AND RESOURCES www.nt.gov.au

Assessment Date

Details

Security Calculation Summary

Sub-Total - All Domains

CONTINGENCY @15%

$37,711,298.21

500,000

$5,656,694.73

$43,367,992.94TOTAL COST

$43,000,000.00Operator Assessment

Total Cost Range Round to Nearest

100

1,000

10,000

Departmental Assessment

100,000

Calculation Trigger

Client RequestAudit FindingNew AuthorisationMMP

Renewal/amendment

Post Closure Management $187,495.21

$2,183,800.00

$12,540.00

8: Access and Haul Roads

9: River Diversions $0.00

$1,851,120.00

$368,890.00

5: Tailings Storage Facilities and Dams

7: Exploration

6: Stockpiles & Waste Rock Dumps $2,367,500.00

$0.00

3: Hard Rock Pits

2: Extractive Workings - Sand, Clay & Gravel

4: Underground Workings

$28,303,722.00

Calculated Cost

$2,436,231.001: Site Infrastructure

Domains

MMP reference

Operator

Mining Officer

LeasesProject

Operator Contact

ADF3-003

M & E Security Calculation Form

Management AreaUnit of

Measure (UOM)

Range per UOM ($)

Cost per UOM ($)

Estimated Quantity

Sub Total ($) Technique Notes

@ 5000-27500 20000.00 1 20000.00This item includes disconnecting all services such as power, water and sewer. This is a 'one off' cost for the area.

m2 70-75 75.00 0 0.00enter the total area of small buildings and offices in the area, including demountables. It does not include workshops.

m2 160-176 176.00 100 17600.00 enter the total area of workshop facilities in the area.

m 100-250 250.00 0 0.00 Enter the total length of conveyors

m2 160-176 176.00 0 0.00enter the total surface are of process plant and mills etc. If multi-story the area should be the sum of the surface area of all floors.

m2 10-30 30.00 500 200.00enter the total area of buildings, workshops etc. Cost dependent on thickness. Assume$10/m2 for <300mm thick, $30/m2 for >300mm thick. (default $12 if unknown)

hr 140-200 200.00 200 40000.00 consider distance to remove all mobile plant to the nearest centre or to Darwin.

m3 2.20-3.50 3.50 1000 3500.00 enter volume of spillage and other contamination for removal to pit or WRD.

@ 35000-165000 0.00 0 0.00 enter the number of tanks

@ 10000-30000 30000.00 1 30000.00 enter the number of tanks

111300.00

@ 5000-5500 5500.00 1 5500.00This item includes disconnecting all services such as power, water and sewer. This is a 'one off' cost for the area.


m2 160-176 176.00 500 88000.00enter the total area of workshop facilities in the area. Are there any remote or field based workshops to include

m2 10-30 30.00 1000 30000.00enter the total area of workshops and buildings. Include any areas of carpark and washdown pads, bulk fuel bunding and refuelling areas.

m3 2.20-6.50 6.50 500 3250.00 enter volume of spillage and other contamination for removal to pit or WRD.

@ 48000-82500 82500.00 1 82500.00 removal of underground tank and all pipework, bunds and any contamination

@ 20000-21000 21000.00 1 21000.00 removal of underground tank and all pipework, bunds and any contamination

@ 200.00 200.00 1 200.00 enter number of tanks

m3 2.20-3.5 3.50 3000 10500.00enter the volume to be removed to pit void for appropriate rehabilitation. If the volume is not known assume a volume of 3000m3 per fuel storage facility.

m3 30-55 55.00 3000 165000.00enter the volume of material requiring onsite remediation. If the volume is not known assume a volume of 3000m3 per fuel storage facility.

413450.00

item 5000-5500 5500.00 1 5500.00This item includes disconnecting all services such as power, water and sewer. This is a 'one off' cost for the area.


m2 160-176 176.00 0 0.00 enter the total area of workshop facilities in the area.

m2 12 12.00 100 1200.00 enter total area of carparks. Includes removal offsite to appropriate facility

m2 10-30 30.00 500 15000.00enter the total area of workshops and buildings.(concrete <300mm @ $10/m2, concrete >300mm @ $30/m2)

@ 650 650.00 1 650.00 assumes removal offsite to a waste disposal facility. Adjust if disposing at onsite facility

59850.00

item 2500-5000 5000.00 1 5000.00This item includes disconnecting all services such as power, water and sewer. This is a 'one off' cost for the area.

m2 70-75 75.00 50 3750.00 enter the total area of small buildings and tanks.

m3 2.20-3.50 3.50 200 700.00 removal to pit void for appropriate rehabilitation

9450.00

Accommodation Campitem 5000-5500 5500.00 1 5500.00

This item includes disconnecting all services such as power, water and sewer. This is a 'one off' cost for the area.

m2 70-75 75.00 500 37500.00 enter the total area of small buildings and tanks.

43000.00

Airstrip, borefields, otherm2 10-30 30.00 500 15000.00 enter total area (concrete <300mm @ $10/m2, concrete >300mm @ $30/m2)

m2 70-75 75.00 200 15000.00 enter area of sheds and tanks

@ 2000-3300 3300.00 12 39600.00 sealing and rehabilitation

@ 500 500.00 5 2500.00 includes sealing and rehabilitation to make safe.

72100.00

ha 440-900 900.00 65 58500.00Enter all areas disturbed by infrasturcture from above, including laydown areasAssume highly disturbed and compacted areas - see assumptions.

m3 1.32-3.40 3.40 65 221.00 assume minimum of 10cm depth

ha6000/ha (or

5/ea)6000.00 65 390000.00

enter total area for revegetation by tubestock. (or enter quantity of tubestock required (<15cm), and density/ha)

deconstruct and remove large tanks - eg leach

deconstruct and remove small tanks

Main Workshop and Stores area

demolish and remove small buildings

demolish and remove industrial workshops and sheds

disconnect and terminate services

remove contaminated material

remove concrete pads and footings

underground tank removal - large hydrocarbon (>5000L)

Domain 1: Infrastructure

Technique



Process Plant, Mill, Crusher area

demolish remove conveyor system

demolish/remove crusher, process plant and mills

remove concrete pads and footings

remove mobile plant

remove contaminated material

Administration

remove concrete pads, footings

waste disposal offsite

underground tank removal - small hydrocarbon (up to 5000L)

above ground tank removal - hydrocarbon

remove hydrocarbon contamination

remove bitumen from sealed carparks etc

Revegetation Activities - all infrastructure areas



remove concrete pads footings and bitumen

demolish and remove sheds and storage tanks

production/dewatering bore closure

observation bore closure


remediation on site of hydrocarbon contamination

remove contaminated soil

disconnect and terminate servicesSewerage/Water treatment plant





Deep rip

source cart and spread topsoil

revegetation by tubestock


Measure (UOM)

Range per UOM ($)

Cost per UOM ($)

Estimated Quantity


Domain 1: Infrastructure

Technique

ha 1200-2000 2000.00 65 130000.00this rate includes acquiring a mix of native tree and shrub species appropriate for the area, mixing and treating the seed and applying by hand at a rate of 4-10kg/ha

ha 140-744 744.00 65 48360.00includes a single application of fertiliser during the initial seeding program - see assumptions

627081.00

Otherkm 9800-11000 11000.00 100 1100000.00 include dismantling and removal of lines and poles from the site

0.00

1100000.00

$2,436,231.00

feriliser application

revegetation by direct seeding

DOMAIN 1 TOTAL

remove powerlines


Measure (UOM)

Range per UOM ($)

Cost per UOM ($)

Estimated Quantity

Sub Total ($)

Technique Notes

Pits m2 1.21-3.00 3.00 1000 3000.00this includes the area requiring reshaping for stabilisation and preparation for revegetation

m3 2.00-4.00 4.00 1000 4000.00 enter volume of material to be backfilled into pit

m 19.00-63.25 63.25 5000 316250.00required where final pit includes steep faces. Includes bund around pit and closure of ramp. Bund assumed to be 2m high and 5m wide at base

ha 700 700.00 10 7000.00 earthworks for banks and drains to manage surface water .

m3 1.32-3.40 3.40 1000 3400.00required if it has not been demonstrated that pit material is suitable as a growth medium

ha 240-500 500.00 10.00 5000.00to enhance vegetation program as required, dependent on material to be ripped eg sand, gravel, clay. Assume low to medium level disturbance - see assumtpions

ha6000/ha (or

5/ea)600.00 2 1200.00 includes acquisition of tubestock, fertiliser and guarding as necessary

ha 1200-2000 2000.00 8 16000.00includes acquiring and spreading a range of native seed by direct broadcast at a rate of 4-10kg/ha.


@ 50 50 100 5000.00 enter number of warning signs as approriate

368290.00

Sediment Management m3 2.5 2.50 200 500.00 enter volume of dam required for sediment traps

m3 1.00 1.00 100 100.00 condsider distance to cart material

Other 0.00

600.00

$368,890.00

signage

Domain 2: Extractive Workings - Sand, Clay & Gravel


sediment traps/dams

Rocks or coarse material lined sediment trap

structural works for drainage

Technique

backfilling of pits

fertiliser application

Scaling, battering for stabilisation

source cart and spread topsoil or growth medium

final trim, deep rip

abandonment bund and pit accessclosed

revegetation by tube stock

DOMAIN 2 TOTAL


Measure (UOM)

Range per UOM ($)

Cost per UOM ($)

Estimated Quantity


Stabilisation of Pits m3 0.7-1.20 0.00Volume is worked out be multiplying length of bench by width and height to reduce angle to make it safe.

m3 1.21-3.00 3.00 1000000 3000000.00 volume requiring reshaping

m 19.00-63.25 63.26 31200 1973712.00required where final pit includes steep faces (>18o). Includes bund (2m high , 5m basearound pit and closure of ramp

ha 440-900 900.00 2240 2016000.00 to enhance vegetation program around pit and pit floors as required

ha 700-1540 1540.00 4 6160.00 earthworks for banks and drains to manage surface water .

m3 1.32-3.40 3.4 1000000.00 3400000.00includes min of 10cm of topsoil to assist revegetation program.

ha6000/ha (or



ha 140 140.00 2240 313600.00 includes a single application of fertiliser during the initial seeding program

m 8.50-30.0 30.00 31200 936000.00 construct a standard stock fence around the site

@ 50 50 1000 50000.00 enter number of warning signs as appropriate

19155472.00

Infill of pits m3 2.00-4.00 4.00 400000 1600000.00 haul and dump of waste rock or tailings. Distance needs to be considered.

m2 550-1100 1100.00 5000 5500000.00 area requiring minor reshaping prior to deep ripping

m3 2.00-5.00 0.00required if it has not been demonstrated that infill material is suitable as a growth medium and only if does not require egineered capping design for ARD/metals mitigation. Assume min thickness of 0.5m

m3 1.32-3.40 0.00includes min of 10cm of topsoil to assist revegetation program.

ha 440-900 900.00 2240 2016000.00 to enhance vegetation program over infilled pit as required

ha 700-1540 0.00earthworks for banks and drains to manage surface water on top of capped pit area if required.

ha6000/ha (or

5/ea)0.00 includes acquisition of tubestock, fertiliser and guarding as necessary

ha 1200-2000 0.00includes acquiring and spreading a range of native seed by direct broadcast at a rate of 4-10kg/ha.

ha 140-744 0.00includes a single application of fertiliser during the initial seeding program - see assumptions

9116000.00

Sediment Management m3 2.50 2.50 10000 25000.00 enter volume of dam required for sediment traps


Other 0.00

32250.00

$28,303,722.00

source cart and spread topsoil if appropriate


shaping or levelling

abandonment bund and pit access closed



infill with tailings or waste rock

source cart and spread suitable material for growth medium

signage

DOMAIN 3 TOTAL


sediment traps/dams



fertiliser applicataion


fencing

Domain 3: Hard Rock Pits and Quarry's

Technique

Drill and blast faces to make safe OR





scaling, battering, pushing walls


Measure (UOM)

Range per UOM ($)

Cost per UOM ($)

Estimated Quantity


@ 1500-2500 0.00barricading of portal with steel grill to make safe and ensure access cnnot be gained buwill allow movement of bats

@ 15000-25000 0.00OR sealing portal with concrete and backfill to make safe and ensure access cannot be gained

@ 10000-25000 0.00 cap shafts using reinforced concrete slab. Dependent on size

m3 8.00-20 0.00 filling of shafts using onsite material

@ 27500 0.00 seal and rehab ventilation fans to make safe.

ha 440-900 0.00 to enhance vegetation program in area as required

ha6000/ha (or




0.00

$0.00

Domain 4: Underground Workings

Technique

barricading portal/declines/adits

sealing portal/decline



Portals, Declines and Shafts

capping/sealing shafts

shaft infilling

seal ventilation fans

DOMAIN 4 TOTAL




Measure (UOM)

Range per UOM ($)

Cost per UOM ($)

Estimated Quantity


Water Dams, Ponds @ 2000-2200 2200.00 5 11000.00 minor earthworks

m3 2.00-4.00 0.00backfilled with onsite material. Haul distance sliding scale from $2/m3 for up to 1km, up to $4/m3 for up to 5km or greater.

m3 2.00-3.52 0.00includes draining the dam to the pit or other appropriate place, removing 500mm of potentially contaminated sediments to be buried in the pit or other disposal area. Must consider the distance from dam to disposal area.

m2 550-1100 0.00 area requiring minor reshaping prior to deep ripping

m3 2.00-5.00 0.00required if it has not been demonstrated that infill material is suitable as a growth medium Assume min thickness of 0.5m


ha 240-440 0.00 to enhance vegetation program over infilled pit as required

ha 700-1540 1540.00 1 1540.00earthworks for banks and drains to manage surface water on top of capped dam area if required.

0.00

ha6000/ha (or



ha 140 0.00 includes a single application of fertiliser during the initial seeding program

12540.00

m3 2.00-5.00 0.00volume of suitable material for capping the TSF. Must have appropriate chemical and physical properites. Required whether for engineered design or growth medium.

ha 25000-49500 0.00required to manage AMD or metals leachate from TSF. Capping layer assumed to be no less than 2m thick.


ha 1400-5500 0.00 area requiring stabilisation and reshaping works around the walls of the emplacement


ha 700-1540 0.00earthworks for banks and drains to manage surface water on top of capped dam area if required.

ha6000/ha (or




@ 20000-200000 0.00where seepage is at unacceptable levels and no wetland filter is in place and company has committed to recovery and treatment of seepage. Depends on size.

ha 5500 0.00 assumes wetland filter is in place and functioning

Other0.00

0.00

$12,540.00

shaping or levelling

DOMAIN 5 TOTAL



spillways


revegetation be direct seeding

apply capping design treatment as required eg 'store and release'


reshape walls and surrounds

Tailings Dams

Domain 5: Tailings Storage Facilities and Dams


fianl trim, deep rip

source cart and spread suitable material for capping/growth medium

Technique

clean water dams - stabilise and make safe

or backfill to natural surface

dirty water dams - drain and remove sediment

seepage management - recovery and treatment

seepage management - wetland filter

revegetation be direct seeding


source cart and spread suitable material for capping





Measure (UOM)

Range per UOM ($)

Cost per UOM ($)

Estimated Quantity

Sub Total ($)

Technique Notes

m2 2.00-3.00this includes the area requiring reshaping for stabilisation and preparation for revegetation (same as below??)

ha 550-1100 1100.00 200 220000.00enter the area requiring minor reshaping to 12-18 o slopes and deep ripping to enhance revegetation

m3 1.21-4.00 4.00 200000 800000.00include volume of material requiring major reshaping to achieve approriate

grades (<18o? Or as specified in MMP) and deep ripping

ha 700-1540 1540.00 5 7700.00 earthworks for banks and drains to manage surface water on top of WRD.

m3 1.32-3.40 3.40 100000 340000.00required if it has not been demonstrated that WRD material is suitable as a growth medium

m3/bcm 3.00-4.00 0.00 carting of stockpiles offsite or WRD to pit. Consider carting distance

ha 440-900 900.00 200.00 180000.00ripping stockpiles or surrounds if required.Assume ripping of waste rock dumps undertaken during reshaping.

ha6000/ha (or




2364500.00

m3 1.21-4.00 0.00include volume of material requiring major reshaping to achieve approriate

grades (<18o or as specified in MMP) and deep ripping

ha 550-1100 0.00enter the are requiring minor reshaping and deep ripping to enhance revegetation

m3 2.00-5.00 0.00volume of suitable material for capping the WRD. Must have appropriate chemical and physical properites.

ha 25000-49500 0.00required to manage AMD or metals leachate from WRD. Capping layer assumed to be no less than 2m thick.

m3/bcm 3.00-4.00 0.00 removal to pit. Haulage distance needs to be considered at an additonal $1/km

m3 1.32-3.40 0.00required if it has not been demonstrated that capping material is suitable as a growth medium


ha 700-1540 0.00earthworks for banks and drains to manage surface water on top of WRD area if required.

ha6000/ha (or




0.00

item 20000-200000 0.00where seepage is at unacceptable levels and no wetland filter is in place and company has committed to recovery and treatment of seepage. Depends on size.

ha 5500 0.00 assumes wetland filter is in place and functioning

m3 2.50 2.50 1000 2500.00 enter volume of dam required for sediment traps


Other 0.00

3000.00

$2,367,500.00

unshaped requiring minor earthworks, trim and deep rip


or removal of stockpiles

dams for sediment control



DOMAIN 6 TOTAL


Leachate and sediment management

Active recovery treatment of problem leachate

Wetland filter



Technique

Recontouring/battering for stabilisation

source cart and spread topsoil or growth medium

unshaped requiring major earthworks, trim and deep rip



unshaped requiring major earthworks, trim and deep rip

trim, deep rip if required

Domain 6: Stockpiles & Waste Rock Dumps

Oxide waste rock dumps and extractive product stockpiles


Waste rock dumps with AMD or metals



source cart and spread suitable material for capping

or removal of stockpiles

unshaped requiring minor earthworks, trim and deep rip

apply capping design treatment eg 'store and release'


Measure (UOM)

Range per UOM ($)

Cost per UOM ($)

Estimated Quantity


@ 50-275 275.00 1000 275000.00Cut collar, insert plug and backfill. Assume using, concrete or plastic cone plugs or bridge (no 'occy' plugs) Depends on number of holes

@ 1250 1250.00 1000 1250000.00 Assume total grouting of drillhole

hole 25-235 235.00 1000 235000.00return cuttings to hole and remove plastic bags to a waste disposal facility. Bags cannobe disposed of on site.

ha 240-440 440.00 3 1100.00Minor ripping/scarifying of pads to depth of 0.3m to assist vegetation in areas of flat/gentle terrain, includes sump infilling. Sumps should not remain open for extended periods of time.

@ 320 320.00 1000 320000.00Required in steep terrain where earthworks required with excavator/dozer to return pad to slope and establish erosion control, includes sump infillingPC650 excavator @320/hr

m3 2.00-3.00 3.00 8000 24000.00 Backfilling of all costeans/trenches. Assumes material does not have to be carted.

m3 2.00-8.00 8.00 1000 8000.00 dependent on depth of pit and if battering of walls required to form to 18o slope

ha 700-1540 1540.00 5 7700.00minor pushing to construct water management structures such as contour banks and diversion drains as required.

m3 1.32-3.40 3.40 1000 3400.00includes min of 10cm of topsoil to assist revegetation program.**this may be carried out when reshaping pads

ha6000/ha (or


ha 1200-2000 2000.00 4 8000.00includes acquiring and spreading a range of native seed by direct broadcast at a rate of 4-10kg/ha if required. Required where area of disturbance is significant.

ha 140 140.00 5 700.00 includes a single application of fertiliser during the initial seeding program

2138900.00

km 120-200 200.00 200 40000.00assume using grader or equivalent to rip to 0.3m and no windrows, establishing erosion control measures (eg bunds) as required

km 440-560 0.00pushing in windrows and ripping track and establishing erosion control measures (ie bunds) across tracks as required

item 1500 1500.00 1 1500.00 includes removal offsite of all grid pegs in exploration area

m3 1.32-3.40 3.40 1000 3400.00includes min of 10cm of topsoil to assist revegetation program.**this could be covered by grading windrows

ha6000/ha (or




44900.00

$2,183,800.00

bulk sample pits



DOMAIN 7 TOTAL

Tracks and Gridlinesripping/scarifying minor tracks and gridlines

ripping major tracks and roads

removal of gridpegs

topsoil replacement if applicable


topsoil replacement if applicable




reshape drill pads

Domain 7: Exploration

Technique

Drillholes, Pads, sumps, costeans

capping drillholes 30cm below ground

grout with concrete

ripping/scarifying pads

infilling costeans

contouring for erosion control

empty and remove plastic sample bags


Measure (UOM)

Range per UOM ($)

Cost per UOM ($)

Estimated Quantity


Haul Roadsm3/bcm 2.50-4.00 0.00

where haul road has been constructed with waste rock material that is leaching ARD removal and disposal in pit or similar will be required

ha 2000-2500 2500.00 140 350000.00 windrows are pulled back and edges battered, area is deep ripped (road 12mwide)

ha 700-1540 1540.00 140 215600.00pushing to construct water management structures such as contour banks and diversion drains as required.

565600.00

Access Roadsm3 12.00 12.00 59500.00 714000.00

Includes area of bitument in roads car parks etc which needs to be removed and disposed of appropriately

ha 2000-2500 2500.00 40 100000.00 windrows are pulled back and edges battered, area is deep ripped (or per km??)

ha 700-1540 1540.00 40 61600.00pushing to construct water management structures such as contour banks and diversion drains as required.

875600.00

m3 1.32-3.40 0.00 assume minimum of 10cm depth

ha6000/ha (or

5/ea)600.00 60 36000.00


ha 1200-2000 2000.00 120 240000.00this rate includes acquiring a mix of native tree and shrub species appropriate for the area, mixing and treating the seed and applying by hand at a rate of 4-10kg/ha


409920.00

$1,851,120.00DOMAIN 8 TOTAL

source cart and spread topsoil


Revegetation activities - all roads


feriliser application

Technique

remove ARD material from road

Domain 8: Access and Haul Roads


reshape and deep rip


reshape and deep rip

breaking and removal of bitumen


Measure (UOM)

Range per UOM ($)

Cost per UOM ($)

Estimated Quantity


Creek/Riverm 165.00 0.00 Includes earthwork repairs and stabilisation following flow events.

ha6000/ha (or

5/ea)0.00


ha 1200-2000 0.00this rate includes acquiring a mix of native tree and shrub species appropriate for the area, mixing and treating the seed and applying by hand at a rate of 4-10kg/ha


0.00

$0.00DOMAIN 9 TOTAL

vegetation by direct seeding

vegetation maintenance

Domain 9: River Diversions

Technique

channel maintenance

vegetation by tubestock


Measure (UOM)

Range per UOM ($)

Cost per UOM ($)

Estimated Quantity


km 10.00-15.00 15.00 260 3900.00 determined based on distance to the mine and machinery used ($/km)

@ 3500 3500.00 1 3500.00 has a contaminated site assessment been undertaken? If not this should be included

1% 37523.80 % of subtotal of all Domains

1% 37523.80 % of subtotal of all Domains (?)(x2-10yrs?)

25,000 25000.00

5000 5000.00

5% 37523.80% of subtotal of all Domains (x2-10yrs?) Monitoring and measurement requirements that may be needed following the closure of the project

10% 37523.80 % of subtotal of all Domains

187495.21

$187,495.21POST CLOSURE TOTAL

other

other

RDPIFR tender preparation and assessment

post closure environmental monitoring

project management and surveying

pest and weed management

Earthwork maintenance

Post Closure Management

Technique

mobilisation/demobilisation

development of unplanned closure report

Contaminated site assessment

mine closure and rehabilitation plan wonarah ...mine closure and rehabilitation plan wonarah...

Documents