Cravotta, C. A., III, & Trahan, M. K. (1999). Limestone drains to increase pH and remove dissolved metals from acidic mine drainage. Appl. Geochem., 14(5), 581–606.
Abstract: Despite encrustation by Fe and Al hydroxides, limestone can be effective for remediation of acidic mine drainage (AMD). Samples of water and limestone (CaCO3) were collected periodically for 1 a at 3 identical limestone-filled drains in Pennsylvania to evaluate the attenuation of dissolved metals and the effects of pH and Fe- and Al-hydrolysis products on the rate of CaCO3 dissolution. The influent was acidic and relatively dilute (pH < 4; acidity < 90 mg) but contained 1-4 mg . L-1 of O-2, Fe3+, Al3+ and Mn2+. The total retention time in the oxic limestone drains (OLDs) ranged from 1.0 to 3.1 hr. Effluent remained oxic (O-2 > 1 mg . L-1) but was near neutral (pH = 6.2-7.0); Fe and Al decreased to less than 5% of influent concentrations. As pH increased near the inflow, hydrous Fe and Al oxides precipitated in the OLDs, The hydrous oxides, nominally Fe(OH)(3) and Al(OH)(3), were visible as loosely bound, orange-yellow coatings on limestone near the inflow. As time elapsed, Fe(OH)(3) and Al(OH)(3) particles were transported downflow. The accumulation of hydrous oxides and elevated pH (> 5) in the downflow part of the OLDs promoted sorption and coprecipitation of dissolved Mn, Cu, Co, Ni and Zn as indicated by decreased concentrations of the metals in effluent and their enrichment relative to Fe in hydrous-oxide particles and coatings on limestone. Despite thick (similar to 1 mm) hydrous-oxide coatings on limestone near the inflow, CaCO3 dissolution was more rapid near the inflow than at downflow points within and the OLD where the limestone was not coated. The high rates of CaCO3 dissolution and Fe(OH3) precipitation were associated with the relatively low pH and high Fe3+ concentration near the inflow. The rate of CaCO3 dissolution decreased with increased pH and concentrations of Ca2+ and HCO3- and decreased Pco(2). Because overall efficiency is increased by combining neutralization and hydrolysis reactions, an OLD followed by a settling pond requires less land area than needed for a two-stagetreatment system consisting of an anoxic limestone drain and oxidation-settling pond or wetland. To facilitate removal of hydrous-oxide sludge, a perforated-pipe subdrain can be installed within an OLD. (C) 1999 Elsevier Science Ltd.
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Coulton, R., Bullen, C., & Hallett, C. (2003). The design and optimisation of active mine water treatment plants. Land Contam. Reclam., 11(2), 273–280.
Abstract: This paper provides a 'state of the art' overview of active mine water treatment. The paper discusses the process and reagent selection options commonly available to the designer of an active mine water treatment plant. Comparisons are made between each of these options, based on technical and financial criteria. The various different treatment technologies available are reviewed and comparisons made between conventional precipitation (using hydroxides, sulphides and carbonates), high density sludge processes and super-saturation precipitation. The selection of reagents (quick lime, slaked lime, sodium hydroxide, sodium carbonate, magnesium hydroxide, and proprietary chemicals) is considered and a comparison made on the basis of reagent cost, ease of use, final effluent quality and sludge settling criteria. The choice of oxidising agent (air, pure oxygen, peroxide, etc.) for conversion of ferrous to ferric iron is also considered. Whole life costs comparisons (capital, operational and decommissioning) are made between conventional hydroxide precipitation and the high density sludge process, based on the actual treatment requirements for four different mine waters.
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Brooks, R. P., Unz, R. F., Davis, L. K., Tarutis, W. J., & Yanchunas, J. (1990). Long-term removal and retention of iron and manganese from acidic mine drainage by wetlands.147.
Abstract: A promising low-technology solution for treating acidic mine drainage (AMD) emanating from coal mined lands involves the use of constructed wetlands.^The research was directed at addressing questions about retention mechanisms for the long-term storage of iron and manganese in constructed wetlands dominated by broad-leaved cattails (Typha latifolia).^Three sites in central Pennsylvania spanning the range of water chemistry parameters found in AMD were investigated.^When the AMD was circumneutral, and metal loadings were low, 79% of the iron, and 48% of the manganese were retained on average.^In the highly acidic site (pH approx.^= 3), < 10% of the metal loadings were retained.^The primary retention mechanism appears to be the formation of metal oxides in the aerobic zones of the sediments.^Although most microbial isolates extracted from sediment cores originated in the aerobic portions of the sediments, there was no evidence that they were transforming metals.^When AMD is circumneutral and metal loadings are low, constructed wetlands can be an effective approach to treating mine drainage.^At sites with highly acidic waters and high metal loadings, the use of constructed wetlands to treat AMD may be ineffectual, and should be implemented with caution.
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Boonstra, J., van Lier, R., Janssen, G., Dijkman, H., & Buisman, C. J. N. (1999). Biological treatment of acid mine drainage. In R. Amils, & A. Ballester (Eds.), Process Metallurgy, vol.9, Part B (pp. 559–567). Biohydrometallurgy and the environment toward the mining of the 21st century; proceedings of the International biohydrometallurgy symposium IBS'99, Part B, Molecular biology, biosorption, bioremediation.
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Bernoth, L., Firth, I., McAllister, P., & Rhodes, S. (2000). Biotechnologies for Remediation and Pollution Control in the Mining Industry. Miner. Metall. Process., 17(2), 105–111.
Abstract: As biotechnologies emerge from laboratories into main-stream application, the benefits they, offer are judged against competing technologies and business criteria. Bioremediation technologies have passed this test and are now widely used for the remediation of contaminated soils and ground waters. Bioremediation includes several distinct techniques that are used for the treatment of excavated soil and includes other techniques that are used for in situ applications. They play an important and growingrole in the mining industry for cost-effective waste management and site remediation. Most applications have been for petroleum contaminants, but advances continue to be made in the treatment of more difficult organ ic and inorganic species. This paper discusses the role of biotechnologies in remediation and pollution control from a mining-industry perspective. Several case studies are presented, including the land application of oily wastewater from maintenance workshops, the composting of hydrocarbon-contaminated soils and sludges, the bioventing of hydrocarbon solvents, the intrinsic bioremediation of diesel hydrocarbons, the biotreatment of cyanide in water front a gold mine, and the removal of manganese from acidic mine drainage.
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