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LaPointe, F., Fytas, K., & McConchie, D. (2005). Using permeable reactive barriers for the treatment of acid rock drainage. International journal of surface mining, reclamation and environment, 19(1), 57–65.
Abstract: Acid mine drainage (AMD) is the most serious environmental problem facing the Canadian mineral industry today. It results from oxidation of sulphide minerals (e.g. pyrite or pyrrhotite) contained in mine waste or mine tailings and is characterized by acid effluents rich in heavy metals that are released into the environment. A new acid remediation technology is presented, by which metallurgical residues from the aluminium extraction industry are used to construct permeable reactive barriers (PRBs) to treat acid mine effluents. This technology is very promising for treating acid mine effluents in order to decrease their harmful environmental effects
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Eger, P., Melchert, G., & Wagner, J. (2000). Using passive treatment systems for mine closure – A good approach or a risky alternative? Min. Eng., 52(9), 78–83.
Abstract: In 1991, LTV Steel Mining decided to close an open-pit taconite mine in northeastern Minnesota using a passive-treatment approach consisting of limiting infiltration into the stockpiles and wetland treatment to remove metals. More than 50 Mt (55 million st) of sulfide-containing waste had been stockpiled adjacent to the mine during its 30 years of operation. Drainage from the stockpiles contained elevated levels of copper, nickel, cobalt and zinc. Nickel is the major trace metal in the drainages. Before the closure, the annual median concentrations ranged from 1.5 to 50 mg/L. Copper, cobalt and zinc are also present but they are generally less than 5% of the nickel values. Median pH levels range from 5 to 7.5, but most of the stockpile drainages have pH levels greater than 6.5. Based on the chemical composition of each stockpile, a cover material was selected. The higher the potential that a stockpile had to produce acid drainage, the lower the permeability of the capping material required. Covers ranged from overburden soil removed at the mine to a flexible plastic liner. Predictions of the reduction in infiltration ranged from 40% for the native soil to more than 90% for the plastic liner. Five constructed wetlands have been installed since 1992. They have removed 60% to 90% of the nickel in the drainages. Total capital costs for all the infiltration reduction and wetlands exceeded $6.5 million, but maintenance costs are less than 1% of those for an active treatment plant. Because mine-drainage problems can continue for more than 100 years, the lower annual operating costs should pay for the construction of the wetland-treatment systems within seven years.
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Simmons, J., Ziemkiewicz, P., & Black, D. C. (2002). Use of Steel Slag Leach Beds for the Treatment of Acid Mine Drainage. Mine Water Env., 21(2), 91–99.
Abstract: Steel slag from the Waylite steel-making plant in Bethlehem, Pennsylvania was leached with acidic mine drainage (AMD) of a known quality using an established laboratory procedure. Leaching continued for 60 cycles and leachates were collected after each cycle. Results indicated that the slag was very effective at neutralizing acidity. The AMD/slag leachates contained higher average concentrations of Ba, V, Mn, Cr, As, Ag, and Se and lower average concentrations of Sb, Fe, Zn, Be, Cd, Tl, Ni, Al, Cu, and Pb than the untreated AMD. Based on these tests, slag leach beds were constructed at the abandoned McCarty mine site in Preston County, West Virginia. The leach beds were constructed as slag check dams below limestone-lined settling basins. Acid water was captured in limestone channels and directed into basins to leach through the slag dams and discharge into a tributary of Beaver Creek. Since installation in October 2000, the system has been consistently producing net alkaline, pH 9 water. The treated water is still net alkaline and has a neutral pH after it encounters several other acidic seeps downstream.
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Carland, R. M. (1995). Use of natural sedimentary zeolites for metal ion recovery from hydrometallurgical solutions and for the environmental remediation of acid mine drainage. Proceedings of the Xix International Mineral Processing Congress, Vol 4, , 95–100.
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Diamond, J. M., Bower, W., & Gruber, D. (1993). Use of man-made impoundment in mitigating acid mine drainage in the North Branch Potomac River. Environ. Manage., 17, 14.
Abstract: The US Department of the Army, Baltimore District Corps of Engineers, oversees a long-term monitoring study to assess and evaluate effects of the Jennings-Randolph reservoir on biota in the North Branch Potomac River. The reservoir was intended, in part, to mitigate effects of acid mine drainage originating in upstream and headwater areas. The present study assessed recovery of benthos and fish in this system, six years after completion of the reservoir. Higher pH and lower iron and sulfate concentrations were observed upstream of the reservoir compared to preimpoundment conditions, suggesting better overall water quality in the upper North Branch. Water quality improved slightly directly downstream of the reservoir. However, the reservoir itself was poorly colonized by macrophytes and benthic organisms, and plankton composition suggested either metal toxicity and/or nutrient limitation. One large tributary to the North Branch and the reservoir (Stony River) was shown to have high (and possibly toxic) levels of manganese, iron, zinc, and aluminum due to subsurface coal mine drainage. Macroinvertebrate diversity and number of taxa were higher in sites downstream of the reservoir in the present study. Compared with previous years, the present study suggested relatively rapid recovery in the lower North Branch due to colonization from two major unimpacted tributaries in this system: Savage River and South Branch Potomac. Abundance of certain mayfly species across sites provided the most clear evidence of longitudinal gradients in water quality parameters and geomorphology. Fish data were consistent with macroinvertebrate results, but site-to-site variation in species composition was greater. Data collected between 1982 and 1987 suggested that certain fish species have unsuccessfully attempted to colonize sites directly downstream of the reservoir despite the more neutral pH water there. Our results show that recovery of biota in the North Branch Potomac was attributed to decreased acid inputs from mining operations and dilution from the Savage River, which contributed better water quality. Continued improvement of North Branch Potomac biota may not be expected unless additional mitigation attempts, either within the reservoir or upstream, are undertaken.
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