Mine Water and the Environment

, Volume 32, Issue 4, pp 302–313 | Cite as

Mine Closure of Pit Lakes as Terminal Sinks: Best Available Practice When Options are Limited?

  • Clint D. McCullough
  • Geneviève Marchand
  • Jörg Unseld
Technical Article

Abstract

In an arid climate, pit lake evaporation rates can exceed influx rates, causing the lake to function as a hydraulic terminal sink, with water levels in the pit remaining below surrounding groundwater levels. We present case studies from Western Australia for two mines nearing closure. At the first site, modelling indicates that waste dump covers for the potentially acid forming (PAF) material would not be successful over the long term (1,000 years or more). The second site is a case study where PAF management is limited by the current waste rock dump location and suitable cover materials. Pit lake water balance modelling using Goldsim software indicated that both pit lakes would function as hydraulic terminal sinks if not backfilled above long-term equilibrium water levels. Poor water quality will likely develop as evapoconcentration increases contaminant concentrations, providing a potential threat to local wildlife. Even so, the best current opportunity to limit the risk of contaminant migration and protect regional groundwater environments may be to limit backfill and intentionally produce a terminal sink pit lake.

Keywords

AMD Backfill Closure Evaporative Groundwater sink Through-flow 

Tagebauseen als endgültige Senke für Bergbauwässer nach Bergbauschließung: Die bestmögliche Praxis unter begrenzten Alternativen?

Zusammenfassung

In aridem Klima ist die Evaporation von Tagebauseen oft höher als die Zuflüsse. In solchen Fällen wirkt der See als endgültige hydraulische Senke, indem der Wasserstand im Tagebau dauerhaft unter dem umgebenden Grundwasserspiegel bleibt. Wir beschreiben zwei Beispiele von Minen in Westaustralien, welche bald geschlossen werden. Im ersten Fall lassen Modelle vermuten, daß die Abdeckung von möglicherweise säurebildenden Halden keine ausreichende Langzeitstabilität (minimal 1000 Jahre) ergäbe. An der zweiten Lokalität ist die Sicherung der möglicherweise säurebildenden Berge durch eine ungünstige Lage der Halde und geeigneten Abdeckmaterials eingeschränkt. Die Modellierung des Wasserhaushaltes der Tagebauseen mit dem Goldsim Programm indiziert, daß beide Seen als endgültige hydraulische Senken fungieren können, wenn die Füllung mit Bergen unter dem Wasserstand langfristiger Gleichgewichtsbedingungen bleibt. Die Wasserqualität wird allerdings durch Evapokonzentration abnehmen, mit möglichen Gefahren für die lokale Tierwelt. Trotzdem ist zur Zeit die Begrenzung der Wiederverfüllung und die bewußte Herstellung eines terminalen Restsees die beste Möglichkeit, das Risiko eines Schadstoffaustrages zu begrenzen und das regionale Grundwasser zu schützen.

Cierre de minas con lagos de pozos como terminales hidráulicos: La práctica más adecuada cuando las opciones están limitadas?

Resumen

En un clima árido, las velocidades de evaporación del lago del pozo de la mina pueden superar las velocidades de entrada de agua, causando que el lago funcione como el sector terminal del flujo hidráulico con sus niveles de agua por debajo de los niveles del agua subterránea de los alrededores. Presentamos el estudio de casos en el oeste de Australia para dos minas cercanas al cierre. Para el primer caso, los modelos indican que la cobertura del material de las colas mineras para evitar la posible formación de ácido (PAF) no sería exitosa en el largo plazo (1000 años o más). En el segundo caso, el manejo del PAF está limitado por la actual localización de las colas y los materiales adecuados para su cobertura. El balance de agua modelado usando el software Goldsim indicó que ambos lagos de pozos de minas actuarían como terminales hidráulicos si no se rellena por encima de los niveles de equilibrio de largo plazo del agua. La evaporación incrementa las concentraciones de los contaminantes siendo la pobre calidad del agua una potencial amenaza para la vida silvestre local. Aún así, la mejor oportunidad que se posee actualmente para limitar el riesgo de migración de contaminantes y proteger el agua subterránea circundante puede ser limitar el relleno e intencionalmente producir un lago en el pozo que sea el terminal hídrico.

坑后的坑湖作水文循点: 无的最佳?

抽象

在干旱地区,当坑湖水蒸量超水量,坑湖水位将低于周地下水水位,而成地下水排泄的点。本文研究了西澳大利两个即将的井。第一个井的模果表明,防止潜在酸(PAF)的排土盖材料将在1000年或更的之后失效。第二个井的潜在酸能力(PAF)受目前排土位置和盖材料的影响。坑湖的Goldsim水均衡算果表明,如果两个坑不被回填至期水均衡水位之上,它将最展成地下水排泄点。蒸作用会提高染物度、化水,当地野生物生存构成潜在威。即便如此,目前限制染物迁移、保区域地下水境的最佳却是限制回填和有意形成一定的坑湖

References

  1. Anderson BR, Gemmell JB, Berry RF (2001) The geology of the Nifty copper deposit, Throssell Group, Western Australia: implications for ore genesis. Econ Geol 96:1535–1565Google Scholar
  2. ANZECC/ARMCANZ, Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand (2000) Australian and New Zealand guidelines for fresh and marine water quality. National Water Quality Management Strategy Paper 4, Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand, Canberra, AustraliaGoogle Scholar
  3. ANZMEC/MCA, Minerals Council of Australia (2000) Strategic framework for mine closure. ANZMEC/Minerals Council of Australia, CanberraGoogle Scholar
  4. BOM, Bureau of Meteorology (2012) Telfer climate averages. http://www.bom.gov.au/climate/averages/tables/cw_009592.shtml. Accessed 18 Oct 2012
  5. Botha PR (2012) The business case for mine closure planning and an overview of anglo American’s mine closure toolbox approach. In: Proceedings of life-of-mine conference, Australasian institute of mining and metallurgy, Melbourne, Australia, pp 7–9Google Scholar
  6. Bredehoft J (2005) The conceptualization problem—surprise. Hydrogeol J 13:37–46CrossRefGoogle Scholar
  7. Carver RN (2004) Nifty copper deposit, Great Sandy Desert, Western Australia. CRC LEME. http://crcleme.org.au/RegExpOre/Nifty.pdf
  8. Castendyk D (2009) Conceptual models of pit lakes. In: Castendyk D, Eary T (eds) Mine pit lakes: characteristics, predictive modeling, and sustainability. Society for Mining Engineering (SME), LittletonGoogle Scholar
  9. Commander DP, Mills CH, Waterhouse JD (1994) Salinisation of mined out pits in Western Australia. In: Proceedings of XXIV congress of the International Association of Hydrogeologists, Adelaide, SA, Australia, pp 527–532Google Scholar
  10. Cooper HH, Jacob CE (1946) A generalized graphical method for evaluating formation constants and summarizing well field history. Am Geophys Union Trans 27:526–534CrossRefGoogle Scholar
  11. DMP, Dept of Mines and Petroleum (2010) DMP bond policy. Departmeny of Mines and Petroleum (DMP), PerthGoogle Scholar
  12. DMP/EPA (2011) Guidelines for preparing mine closure plans. Western Australian DMP, Environmental Protection Authority of Western Australia (EPA), PerthGoogle Scholar
  13. Eary LE (1998) Predicting the effects of evapoconcentration of water quality in pit lakes. Geochem Explor 64:223–236CrossRefGoogle Scholar
  14. Eary LE (1999) Geochemical and equilibrium trends in mine pit lakes. Appl Geochem 14:963–987CrossRefGoogle Scholar
  15. Fetter CW (1994) Applied hydrogeology, 3rd edn. University of Wisconsin, OshkoshGoogle Scholar
  16. Gammons CH, Harris LN, Castro JM, Cott PA, Hanna BW (2009) Creating lakes from open pit mines: processes and considerations, with emphasis on northern environments. Canadian Technical Report of Fisheries and Aquatic Sciences 2826, Ottawa, CanadaGoogle Scholar
  17. Goldsim (2011) GoldSim. GoldSim Technology Group, Washington DC, USAGoogle Scholar
  18. Gvirtzman H (2006) Groundwater hydrology and paleohydrology at the Dead Sea rift valley. In: Enzel Y, Agnon A, Stein M (eds) New frontiers in Dead Sea paleoenvironmental research. GSA Book, Washington, DC, pp 95–111CrossRefGoogle Scholar
  19. Hilson G, Haselip J (2004) The environmental and socioeconomic performance of multinational mining companies in the developing world economy. Min Energ 19:25–47CrossRefGoogle Scholar
  20. Hinwood A, Heyworth J, Tanner H, McCullough CD (2012) Recreational use of acidic pit lakes—human health considerations for post closure planning. J Water Resour Protect 4:1061–1070CrossRefGoogle Scholar
  21. Hoy RD (1977) Pan and lake evaporation in northern Australia. In: Proceedings of hydrology symposium. Institute of Engineers, Brisbane, Australia, pp 57–61Google Scholar
  22. Hoy RD, Stephens SK (1979) Field study of lake evaporation–analysis of data from phase 2 storages and a summary of phase 1 and phase 2. Technical Paper 41, Australian Water Resources Council, Canberra, AustraliaGoogle Scholar
  23. Huston DL, Maas R, Czarnota K (2005) The age and genesis of the Nifty copper deposit: back to the future. Geoscience Australia, CanberraGoogle Scholar
  24. ICMM, International Council on Mining and Metals (2008) Planning for integrated mine closure: toolkit. International Council on Mining and Metals, London, UKGoogle Scholar
  25. Johnson SL, Wright AH (2003) Mine void water resource issues in Western Australia. Hydrogeological record series. Report HG 9, Water and Rivers Commission, Perth, AustraliaGoogle Scholar
  26. Jones H, McCullough CD (2011) Regulator guidance and legislation relevant to pit lakes. In: McCullough CD (ed) Mine pit lakes: closure and management. Australian Centre for Geomechanics, Perth, pp 137–152Google Scholar
  27. Kuipers JR (2002) Water treatment as a mitigation. Southwest Hydrol 1:18–19Google Scholar
  28. Kumar NR, McCullough CD, Lund MA, Newport M (2011) Sourcing organic materials for pit lake remediation in remote mining regions. Mine Water Environ 30:296–301CrossRefGoogle Scholar
  29. Kumar RN, McCullough CD, Lund MA (2012) Pit lakes in Australia. In: Geller W, Schultze M, Kleinmann RLP, Wolkersdorfer C (eds) Acidic pit lakes—legacies of surface mining on coal and metal ores. Springer, Berlin, pp 342–361Google Scholar
  30. MCA (1997) Minesite water management handbook. Minerals Council of Australia, CanberraGoogle Scholar
  31. McCullough CD (2008) Approaches to remediation of acid mine drainage water in pit lakes. Int J Min Reclam Environ 22:105–119CrossRefGoogle Scholar
  32. McCullough CD, Lund MA (2006) Opportunities for sustainable mining pit lakes in Australia. Mine Water Environ 25:220–226CrossRefGoogle Scholar
  33. McCullough CD, Van Etten EJB (2011) Ecological restoration of novel lake districts: new approaches for new landscapes. Mine Water Environ 30:312–319CrossRefGoogle Scholar
  34. McCullough CD, Hunt D, Evans LH (2009) Sustainable development of open pit mines: creating beneficial end uses for pit lakes. In: Castendyk D, Eary T (eds) Mine pit lakes: characteristics, predictive modeling, and sustainability. SME, Littleton, pp 249–268Google Scholar
  35. Miller GE, Lyons WB, Davis A (1996) Understanding the water quality of pit lakes. Environ Sci Technol 30:118A–123ACrossRefGoogle Scholar
  36. Niccoli WL (2009) Hydrologic characteristics and classifications of pit lakes. In: Castendyk D, Eary T (eds) Mine pit lakes: characteristics, predictive modeling, and sustainability. SME, Littleton, pp 33–43Google Scholar
  37. Puhalovich AA, Coghill M (2011) Management of mine wastes using pit/underground void backfilling methods: current issues and approaches. In: McCullough CD (ed) Mine pit lakes: closure and management. Australian Centre for Geomechanics, Perth, pp 3–14Google Scholar
  38. Schultze M, Boehrer B, Friese K, Koschorreck M, Stasik S, Wendt-Potthoff K (2011) Disposal of waste materials at the bottom of pit lakes. In: Fourie AB, Tibbett M, Beersing A (eds) In: Proceedings of 6th international conference on mine closure, Lake Louise, Canada, Australian Centre for Geomechanics, Perth, pp 555–564Google Scholar
  39. Srikanthan R, McMahon TA (1985) Stochastic generation of rainfall and evaporation data. Technical Paper 84 Australian Water Resources Council, Canberra, AustraliaGoogle Scholar
  40. Vandenberg J (2011) Use of water quality models for design and evaluation of pit lakes. In: McCullough CD (ed) Mine pit lakes: closure and management. Australian Centre for Geomechanics, Perth, pp 63–80Google Scholar
  41. Williams DJ (2012) Some mining applications of unsaturated soil mechanics. Geotech Eng J SEAGS AGSSEA 43:83–98Google Scholar
  42. Younger PL (2002) Mine waste or mine voids: which is the most important long-term source of polluted mine drainage? United Nations Environment Programme, Mineral Resources Forum: current feature paperGoogle Scholar
  43. Younger PL, Wolkersdorfer C (2004) Mining impacts on the fresh water environment: technical and managerial guidelines for catchment scale management. Mine Water Environ 23:S2–S80CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Clint D. McCullough
    • 1
    • 2
  • Geneviève Marchand
    • 1
  • Jörg Unseld
    • 1
    • 3
  1. 1.Golder Associates Pty LtdWest PerthAustralia
  2. 2.Mine Water and Environment Research Centre (MiWER)Edith Cowan UniversityJoondalupAustralia
  3. 3.FMGPerthAustralia

Personalised recommendations