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Overview. Mining Act 1978 requirementsDepartmental basic closure criteriaRelinquishment processMost common errorsDMP expectationsExamples (good
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1. Regulator Expectations for Site Relinquishment Eugene Bouwhuis (Senior Environmental Inspector)
20 May 2009
2. Mining Regulations 1981
Each site varies dependent upon issues/ social/ community/ environmental/ safety
Mining Regulations 1981
Each site varies dependent upon issues/ social/ community/ environmental/ safety
3. Mining Act 1978 requirements All mining tenements granted in Western Australia have a number of environmental requirements under the Mining Act 1978 and Regulations 1981
The Minister may impose conditions at any time including environmental bondsThe Minister may impose conditions at any time including environmental bonds
4. Mining Act 1978 requirements Environmental Conditions
Mining Proposals (Section 70O)
Environmental Bonds
Regulation / Enforcement
Community Consultation (MP guidelines)
Mine Closure / Rehabilitation (“ “ “)
Mining Act Amendment Act 2004 proclaimed 10 Feb 2006
Mining Proposal are prescribed document 70O
UPB guaranteed by a bank or approved financial institution
120H Direction To Modify
120M Stop Work Order
Inspectors appointed under section 11
Section 4.6 of MP Guideline Consultation land owners Land vestees
Section 4.7 requires preliminary mine closure planMining Act Amendment Act 2004 proclaimed 10 Feb 2006
Mining Proposal are prescribed document 70O
UPB guaranteed by a bank or approved financial institution
120H Direction To Modify
120M Stop Work Order
Inspectors appointed under section 11
Section 4.6 of MP Guideline Consultation land owners Land vestees
Section 4.7 requires preliminary mine closure plan
5. DMP basic closure criteria Safe
Stable
Non-polluting
Self sustaining native ecosystem/or agreed alternative end land-use Safe for humans and animals. Native fauna / stock.
Stable landforms essential.
No dusting, no leachates (salt and AMD), no elevated metals or elements above background.
Land owner or vestee must accept in writing liability and responsibility for the site post mining.Safe for humans and animals. Native fauna / stock.
Stable landforms essential.
No dusting, no leachates (salt and AMD), no elevated metals or elements above background.
Land owner or vestee must accept in writing liability and responsibility for the site post mining.
6. Relinquishment process Rehabilitate & monitor site
Allow time
Provide documentation to support request for relinquishment
DMP Senior EO conducts inspection & makes recommendations to Director
Bonds retired, conditions deleted
Tenements surrendered
Collection of baseline and supportive relevant data.
May take many years hence progressive rehabilitation important.
Need to be exposed to representative climatic conditions. Eg drought.
Monitoring results summary and interpretation by appropriate expertise.Collection of baseline and supportive relevant data.
May take many years hence progressive rehabilitation important.
Need to be exposed to representative climatic conditions. Eg drought.
Monitoring results summary and interpretation by appropriate expertise.
7. Most common errors Poor knowledge of materials
Inadequate stakeholder consultation
Variance from commitments
Poor environmental management/ supervision
Fail to seek appropriate technical input
Inadequate financial provisioning
No/inadequate rehab. trials
Inadequate monitoring
Dispersive / hostile waste materials.
Various stakeholders govt/community/private land.
Consult with all stakeholders early.
Meet other approval requirements eg. Ministerial conditions EP Act 1986.
The approved documents and contents are legally binding.
Landforms to cope with 1 in 100 year, 72h storm event.
Poor supervision can result in very costly reworks.
Difficult issues may require input from various technical experts.
Closure and relinquishment is very expensive. Appropriate resourcing is required.
No historic data presented, no trends over time.Dispersive / hostile waste materials.
Various stakeholders govt/community/private land.
Consult with all stakeholders early.
Meet other approval requirements eg. Ministerial conditions EP Act 1986.
The approved documents and contents are legally binding.
Landforms to cope with 1 in 100 year, 72h storm event.
Poor supervision can result in very costly reworks.
Difficult issues may require input from various technical experts.
Closure and relinquishment is very expensive. Appropriate resourcing is required.
No historic data presented, no trends over time.
8. DMP expectations 1) Pits
Abandonment bund (zone of instability)
Backfilled (allow for settlement)
Acceptable pit water quality (eg.not at significant variance to background levels)
Other potential uses (pit lake, reformed into the surrounding topography Surface infrastructure – public roads, rail, town sites, private land, neighbouring tenements, reserve land.
Aquiculture, recreational, water source, in-pit TSF.Surface infrastructure – public roads, rail, town sites, private land, neighbouring tenements, reserve land.
Aquiculture, recreational, water source, in-pit TSF.
9. DMP expectations 2) Tailings Storage Facilities (TSFs)
Stability analysis/ geotechnical evaluation
Capped appropriately
Ground water quality acceptable
Vegetation (rehab. & surrounding)
Surface water management (1:100 rainfall/ 72 hour) Guidelines for safe design and operating standards for TSFs.
Categories 1 to 3
Hazard ratings
Concave, convex for final surfaces.Guidelines for safe design and operating standards for TSFs.
Categories 1 to 3
Hazard ratings
Concave, convex for final surfaces.
10. DMP expectations 3) Waste dumps
Long term safe, stable, non-polluting landform
Final design well trialled
Hostile material well encapsulated
Good surface drainage control
Functioning native ecosystem Monitoring results.
Dispersive materials, materials prone to piping.
Monitoring results against an analogue.Monitoring results.
Dispersive materials, materials prone to piping.
Monitoring results against an analogue.
11. DMP expectations 4) Plant, workshops, offices & camps
Totally deconstructed
Hazardous substances removed
Contaminated areas treated
Concrete foundations removed/buried
Drainage control implemented
All rubbish removed (foreign debris)
Revegetated Buildings, poer cables, pipelines (gas, water, tailings, chemical).
Hydrocarbons, process liquors, chemicals, bioremediation.
Surface drainage re-instated.
Buildings, poer cables, pipelines (gas, water, tailings, chemical).
Hydrocarbons, process liquors, chemicals, bioremediation.
Surface drainage re-instated.
12. DMP expectations 5) Infrastructure (eg. haul rds, airstrips, pipelines, powerlines, borefields, borrow pits)
Ripped up & structures removed
Bores sealed (or accepted by 3rd party)
Dams – liners removed, backfilled
Spill areas remediated
Spread with topsoil & revegetated Legally able to eg. Pastoralists retaining bore or road or airstrip. Must be ratified by Pastoral Lands Board as a legitimate pastoral improvement.Legally able to eg. Pastoralists retaining bore or road or airstrip. Must be ratified by Pastoral Lands Board as a legitimate pastoral improvement.
13. Poor examples Poor design (batters too long)
Topsoil excessive
Lack of armouring
Poor surface water management Water Induced Erosion due to poor material selection and construction.Water Induced Erosion due to poor material selection and construction.
14. Poor examples Poor placement of waste dump
Poor knowledge of site drainage Interference with drainage resulting in ponding of surface water against mine infrastructure and AMD.Interference with drainage resulting in ponding of surface water against mine infrastructure and AMD.
15. Poor examples Poor environmental management (salts leaching from mine waste landform)
16. Poor examples Acid mine drainage
No topsoil recovery
17. Good examples Progressive rehabilitation
Fresh topsoil & not excessively thick
Good design
18. Good examples Contoured to integrate with surrounding landforms
Fauna habitat provided
19. Good examples Private land post mining with improvements Re-contoured land, water source, pasture improvements, fencing, solar pumps, buildings, roads.Re-contoured land, water source, pasture improvements, fencing, solar pumps, buildings, roads.
20. Have realistic expectations Don’t expect bond reductions the day after machinery leaves the waste dump
Don’t seek relinquishment with no/ inadequate monitoring data
Consider position of regulator (responsible for interests of the WA community)
21. Take home messages Positive steps towards relinquishment:
Engage stakeholders, establish end land-use
Know your waste materials
Strip topsoil progressively
Develop/Fine tune completion criteria
Progressively rehabilitate
Trial (test, monitor, evaluate)
22. Thankyou - any questions?
Eugene Bouwhuis
Mineral House
100 Plain Street, East Perth
eugene.bouwhuis@dmp.wa.gov.au
Ph. (08) 9222 3097 The end