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Kuyucak, N. (2002). Acid mine drainage prevention and control options. CIM Bull., 95(1060), 96–102.
Abstract: Acid mine drainage (AMD) is one of the most significant environmental challenges facing the mining industry worldwide. It occurs as a result of natural oxidation of sulphide minerals contained in mining wastes at operating and closed/decommissioned mine sites. AMD may adversely impact the surface water and groundwater quality and land use due to its typical low pH, high acidity and elevated concentrations of metals and sulphate content. Once it develops at a mine, its control can be difficult and expensive. If generation of AMD cannot be prevented, it must be collected and treated. Treatment of AMD usually costs more than control of AMD and may be required for many years after mining activities have ceased. Therefore, application of appropriate control methods to the site at the early stage of the mining would be beneficial. Although prevention of AMD is the most desirable option, a cost-effective prevention method is not yet available. The most effective method of control is to minimize penetration of air and water through the waste pile using a cover, either wet (water) or dry (soil), which is placed over the waste pile. Despite their high cost, these covers cannot always completely stop the oxidation process and generation of AMD. Application of more than one option might be required. Early diagnosis of the problem, identification of appropriate prevention/control measures and implementation of these methods to the site would reduce the potential risk of AMD generation. AMD prevention/control measures broadly include use of covers, control of the source, migration of AMD, and treatment. This paper provides an overview of AMD prevention and control options applicable for developing, operating and decommissioned mines.
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Benner, S. G., Blowes, D. W., & Ptacek, C. J. (1997). A full-scale porous reactive wall for prevention of acid mine drainage. Ground Water Monitoring and Remediation, 17(4), 99–107.
Abstract: The generation and release of acidic drainage containing high concentrations of dissolved metals from decommissioned mine wastes is an environmental problem of international scale. A potential solution to many acid drainage problem is the installation of permeable reactive walls into aquifers affected by drainage water derived from mine waste materials. A permeable reactive wall installed into an aquifer impacted by low-quality mine drainage waters was installed in August 1995 at the Nickel Rim mine site near Sudbury, Ontario. The reactive mixture, containing organic matter, was designed to promote bacterially mediated sulfate reduction and subsequent metal sulfide precipitation. The reactive wall is installed to an average depth of 12 feet (3.6 m) and is 49 feet (15 m) long perpendicular to ground water flow. The wall thickness (flow path length) is 13 feet (4 m). Initial results, collected nine months after installation, indicate that sulfate reduction and metal sulfide precipitation is occurring. Comparing water entering the wall to treated water existing the wall, sulfate concentrations decrease from 2400 to 4600 mg/L to 200 to 3600 mg/L; Fe concentration decrease from 250 to 1300 mg/L to 1.0 to 40 mg/L, pH increases from 5.8 to 7.0; and alkalinity (as CaCO<inf>3</inf>) increases from 0 to 50 mg/L to 600 to 2000 mg/L. The reactive wall has effectively removed the capacity of the ground water to generate acidity on discharge to the surface. Calculations based on comparison to previously run laboratory column experiments indicate that the reactive wall has potential to remain effective for at least 15 years.
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Wingenfelder, U., Hansen, C., Furrer, G., & Schulin, R. (2005). Removal of heavy metals from mine waters by natural zeolites. Environ Sci Technol, ES & T, 39(12), 4606–4613.
Keywords: Groundwater problems and environmental effects Pollution and waste management non radioactive remediation heavy metal mine drainage acid mine drainage; acidification; Central Europe; chemical composition; chemical fractionation; dissolved materials; Europe; framework silicates; geochemistry; grain size; heavy metals; hydrochemistry; ion exchange; lead; metals; mines; mining; mobilization; models; pH; pollutants; pollution; precipitation; remediation; samples; silicates; spectra; Switzerland; toxic materials; X-ray diffraction data; X-ray fluorescence spectra; zeolite group
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Fisher, T. S. R., & Lawrence, G. A. (2006). Treatment of acid rock drainage in a meromictic mine pit lake. Journal of environmental engineering, 132(4), 515–526.
Abstract: The Island Copper Mine pit near Port Hardy, Vancouver Island, B.C., Canada, was flooded in 1996 with seawater and capped with fresh water to form a meromictic (permanently stratified) pit lake of maximum depth 350 m and surface area 1.72 km2. The pit lake is being developed as a treatment system for acid rock drainage. The physical structure and water quality has developed into three distinct layers: a brackish and well-mixed upper layer; a plume stirred intermediate layer; and a thermally convecting lower layer. Concentrations of dissolved metals have been maintained well below permit limits by fertilization of the surface waters. The initial mine closure plan proposed removal of heavy metals by metal-sulfide precipitation via anaerobic sulfate-reducing bacteria, once anoxic conditions were established in the intermediate and lower layers. Anoxia has been achieved in the lower layer, but oxygen consumption rates have been less than initially predicted, and anoxia has yet to be achieved in the intermediate layer. If anoxia can be permanently established in the intermediate layer then biogeochemical removal rates may be high enough that fertilization may no longer be necessary. < copyright > 2006 ASCE.
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Ye, Z. H., Whiting, S. N., Qian, J. H., Lytle, C. M., Lin, Z. Q., & Terry, N. (2001). Trace element removal from coal ash leachate by a 10-year-old constructed wetland. J. Environ. Qual., 30(5), 1710–1719.
Abstract: This study investigated the ability of a 10-yr-old constructed wetland to treat metal-contaminated leachate emanating from a coal ash pile at the Widows Creek electric utility, Alabama (USA). The two vegetated cells, which were dominated by cattail (Typha latifolia L.) and soft rush (Juncus effusus L.), were very effective at removing Fe and Cd from the wastewater, but less efficient for Zn, S, B, and Mn. The concentrations were decreased by up to 99% for Fe, 91% for Cd, 63% for Zn, 61% for S, 58% for Mn, and 50% for B. Higher pH levels (>6) in standing water substantially improved the removing efficiency of the wetland for Mn only. The belowground tissues of both cattail and soft rush had high concentrations of all elements; only for Mn, however, did the concentration in the shoots exceed those in the belowground tissues. The concentrations of trace elements in fallen litter were higher than in the living shoots, but lower than in the belowground tissues. ne trace element accumulation in the plants accounted for less than 2.5% of the annual loading of each trace element into the wetland. The sediments were the primary sinks for the elements removed from the wastewater. Except for Mn, the concentrations of trace elements in the upper layer (0-5 cm) of the sediment profile tended to be higher than the lower layers (5-10 and 10-15 cm). We conclude that constructed wetlands are still able to efficiently remove metals in the long term (i.e., >10 yr after construction).
Keywords: acid mine drainage; Alabama; ash; bioaccumulation; boron; cadmium; constructed wetlands; environmental analysis; environmental effects; iron; Jackson County Alabama; Juncus effusus; leachate; manganese; metals; pH; pollutants; pollution; remediation; soils; sulfur; trace elements; Typha latifolia; United States; vegetation; waste water; wetlands; Widows Creek; Widows Creek Steam Plant; zinc; Typha; Juncus 22, Environmental geology
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