Mine closure and sustainable water management by prof carolyn oldham

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Mine closure and sustainable water management by prof carolyn oldham

  1. 1. Mine closure and sustainable water management Prof. Carolyn Oldham School of Environmental Systems Engineering
  2. 2. Mine Lake 116 Central German coal district
  3. 3. Photo: T. Fischer Island Copper Lake British Columbia, Canada
  4. 4. Lake Stockton Collie coal district
  5. 5. Lake Stockton Collie coal district
  6. 6. Gravel pit Central German coal district
  7. 7. Chicken Creek Pit, Collie Coal Basin
  8. 8. Sustainable water management • Optimisation: – Impact on downstream water resources – Impact on environment – Beneficial end uses – Social impact – Ongoing management costs – Mine operations • Unlikely to be a “walk-away” solution
  9. 9. Outline • Mine life stages • Conceptual model • Water balances • Water quality modelling • Validation • AMCER Protocol
  10. 10. Phases of mine life Island Copper Lake British Columbia, Canada Photo: T. Fischer
  11. 11. Exploration No solution: reassess? data, decision: Mine feasible 1. Collate any General existing site data 1. Mine plan, conceptual history model 2. Site-specific conceptual model WQ modelling 3. Quantify/predict likely tools WQ evolution Flow chart of mine 4. Assess potential environmental 4. Scenario testing: impact and end uses - prevention possible? WQ - remediation possible? water assessment “poor” - backfilling feasible? WQ good/ - downstream mitigation? impact acceptable 5. Design and begin data collection program 6. Document all data, calculations (+assumptions), sampling plan 7. As input data collected, update predictions Goal: pit lake with 8. As external and internal validation data beneficial end uses or collected, test prediction; acceptable impact for if necessary, improve minimum cost
  12. 12. Development of a hydrological conceptual model
  13. 13. Development of a lake conceptual model
  14. 14. Bathymetry Island Copper Lake British Columbia, Canada
  15. 15. Bathymetry - landscaping WO5B Collie, Australia
  16. 16. Meteorological data Photo: T. Fischer Island Copper Lake British Columbia, Canada
  17. 17. Mass balances - groundwater inflow Chicken Creek Collie, Australia
  18. 18. Mass balances - inputs from surface runoff
  19. 19. Exploration No solution: reassess? data, decision: Mine feasible 1. Collate any General existing site data 1. Mine plan, conceptual history model 2. Site-specific conceptual model WQ modelling 3. Quantify/predict likely tools WQ evolution Flow chart of mine 4. Assess potential environmental 4. Scenario testing: impact and end uses - prevention possible? WQ - remediation possible? water assessment “poor” - backfilling feasible? WQ good/ - downstream mitigation? impact acceptable 5. Design and begin data collection program 6. Document all data, calculations (+assumptions), sampling plan 7. As input data collected, update predictions Goal: pit lake with 8. As external and internal validation data beneficial end uses or collected, test prediction; acceptable impact for if necessary, improve minimum cost
  20. 20. Water balances - inputs
  21. 21. Water balance - outputs
  22. 22. Water balance
  23. 23. Meteorological data Huber et al. 2008
  24. 24. Impact of wind speeds on water balance
  25. 25. Impact of wind sheltering on water levels 100% surface wind speed 10% surface wind speed
  26. 26. Effect of wind on stratification Huber et al. 2008
  27. 27. Effect of wind sheltering on stratification DYRESM - 100% surface wind speed DYRESM - 10% surface wind speed
  28. 28. Exploration No solution: reassess? data, decision: Mine feasible 1. Collate any General existing site data 1. Mine plan, conceptual history model 2. Site-specific conceptual model WQ modelling 3. Quantify/predict likely tools WQ evolution Flow chart of mine 4. Assess potential environmental 4. Scenario testing: impact and end uses - prevention possible? WQ - remediation possible? water assessment “poor” - backfilling feasible? WQ good/ - downstream mitigation? impact acceptable 5. Design and begin data collection program 6. Document all data, calculations (+assumptions), sampling plan 7. As input data collected, update predictions Goal: pit lake with 8. As external and internal validation data beneficial end uses or collected, test prediction; acceptable impact for if necessary, improve minimum cost
  29. 29. Mass balances - AMD from walls Chicken Creek Collie, Australia
  30. 30. Mass balances - AMD from overburden runoff Chicken Creek Collie, Australia
  31. 31. Surface inflow assumptions CAEDYM - Fe(III) and Fe(II) – CAEDYM - Fe(III) and Fe(II) – assuming 100% seepage through assuming 10% seepage through black shale black shale
  32. 32. During Filling Monitoring • Geochemical characterisation of mine void and surrounds, to determine changes in contaminant release • Changing pit bathymetry • On-site meteorological forcing • Establish current and predicted mass balances • On-site water column sensor chains • Water quality sampling
  33. 33. Mass balances - inflows Island Copper Lake British Columbia, Canada Photo: T. Fischer
  34. 34. On-site water column sensor chains Photo: T. Fischer
  35. 35. On-site water column sensor chains WO5B Collie, Australia
  36. 36. Lake Kepwari Collie, Australia river diversion LDS data, Oct 2003-May 2005 2003-
  37. 37. Post-filling Monitoring • Geochemical characterisation of local mineralogy • Geochemical characterisation of source waters • On-site meteorological forcing • Establish current and predicted mass balances • On-site water column sensor chains • Water quality sampling
  38. 38. Water quality sampling temperature, salinity, dissolved oxygen pH turbidity
  39. 39. T salinity DO% sat
  40. 40. Water quality sampling LakeKepwari Collie coal istrict
  41. 41. Water quality sampling LakeKepwari Colliecoal district
  42. 42. Water quality sampling river diversion LDS data, Oct 2003-May 2005
  43. 43. Water Quality Modelling • Range of models – Lake stratification models – Geochemical models – Ecological models All require input data
  44. 44. Model validation Field DYRESM
  45. 45. Forward prediction - 10 year
  46. 46. Where to start Oldham et al., ACMER Protocol
  47. 47. Where to start Oldham et al., ACMER Protocol
  48. 48. Exploration No solution: reassess? data, decision: Mine feasible 1. Collate any General existing site data 1. Mine plan, conceptual history model 2. Site-specific conceptual model WQ modelling 3. Quantify/predict likely tools WQ evolution Flow chart of mine 4. Assess potential environmental 4. Scenario testing: impact and end uses - prevention possible? WQ - remediation possible? water assessment “poor” - backfilling feasible? WQ good/ - downstream mitigation? impact acceptable 5. Design and begin data collection program 6. Document all data, calculations (+assumptions), sampling plan 7. As input data collected, update predictions Goal: pit lake with 8. As external and internal validation data beneficial end uses or collected, test prediction; acceptable impact for if necessary, improve minimum cost
  49. 49. The team The funding Team leaders Carolyn Oldham Australian Research Greg Ivey Council Jason Plumb, CSIRO ACMER Research Assoc.BibhashNath Centre for Sustainable Ursula Salmon Mine Lakes Matt Hipsey, CWR State Government of Geoff Wake Western Australia PhD students Deborah Read Wesfarmers Premier Coal Huynh Pham Griffin Coal Masters students Anita Huber Sons of Gwalia Alisa Krasnostein Collie Shire Council Honours students Emma Craven University of Western Peter Chapman Australia Tung Nguyen ManuellaSusanto Alice Turnbull Tom Zdun Aaron Brunt
  50. 50. Thank you

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