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Author Eger, P.; Melchert, G.; Wagner, J.
Title Using passive treatment systems for mine closure – A good approach or a risky alternative? Type Journal Article
Year 2000 Publication Min. Eng. Abbreviated Journal
Volume 52 Issue 9 Pages 78-83
Keywords Pollution and waste management non radioactive Groundwater problems and environmental effects geological abstracts: environmental geology (72 14 2) geomechanics abstracts: excavations (77 10 10) acid mine drainage decommissioning mine waste open pit mine pH remediation
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.
Address P. Eger, Minnesota Dept. of Natural Rsrces., St. Paul, MN, United States
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ISSN 0026-5187 ISBN Medium
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Notes Using passive treatment systems for mine closure – A good approach or a risky alternative?; 2285715; United-States 19; Geobase Approved no
Call Number (up) CBU @ c.wolke @ 17539 Serial 392
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Author Smith, I.J.H.
Title AMD treatment, it works but are we using the right equipment? Type Journal Article
Year 2000 Publication Tailings and mine waste ' Abbreviated Journal
Volume Issue Pages 419-427
Keywords Groundwater problems and environmental effects geomechanics abstracts: excavations (77 10 10) acid mine drainage conference proceedings methodology mine drainage remediation waste management
Abstract For the past 40 years various approaches have been developed to treat acid waters coming from abandoned as well as operating mining operations. System designs have evolved to meet increasingly stringent discharge permit limits for treated water, as well as to provide solid disposal within economic constraints. A treatment system for remediation of acid mine drainage (AMD) or acid groundwater (AG) requires two main steps: 1. The addition of chemicals to precipitate dissolved metals contained in the waters, and if necessary, to coagulate the precipitated solids ahead of physical separation. 2. Physical separation of the precipitated solids from the water so the water can be lawfully discharged from the site. Choosing the appropriate technology and equipment results in the most efficient plant design, the lowest capital outlay, and minimum operating cost. The goal of these plants is to discharge liquids and solids able to meet standards. The separation of solids from liquids can be achieved through various means, including gravity settling, flotation, mechanical dewatering, filtration and evaporation. As important as the liquid solids separation unit operations are, they are driven by the chemistry of the water to be treated. The content of the dissolved solids will influence the quality and quantity of the solids produced during precipitation. Thus the two aspects must be integrated, with chemistry first, then mechanical engineering. This presentation will provide an overview of a number of liquid solids separation tools currently being used to treat AMD-AG at several sites in the USA. It will also discuss how their operations are impacted by the chemistry of their particular acid water feeds. The tools used include clarifier-thickeners, solids contact clarifiers, dissolved air flotation, polishing filters, membrane filters, and mechanical dewatering devices (belt and filter presses, vacuum filters, and driers).
Address J.H. Smith III, SEPCO Incorporated, Fort Collins, CO, United States
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Notes Book; Conference-Paper; AMD treatment, it works but are we using the right equipment?; 2263351; Using Smart Source Parsing 00-Proceedings-of-the-7th-international-conference-Fort-Collins-January- 2000 Netherlands; Geobase Approved no
Call Number (up) CBU @ c.wolke @ 17541 Serial 237
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Author Dunn, J.; Russell, C.; Morrissey, A.
Title Remediating historic mine sites in Colorado Type Journal Article
Year 1999 Publication Min. Eng. Abbreviated Journal
Volume 51 Issue 8 Pages 32-35
Keywords Reclamation and conservation Groundwater problems and environmental effects geological abstracts: environmental geology (72 14 1) geomechanics abstracts: excavations (77 10 10) abandoned mine acid mine drainage environmental effect remediation United States Colorado
Abstract This article provides examples of reclamation and remediation in Colorado watersheds. The projects were undertaken by the US Environmental Protection Agency (EPA) Region 8, in cooperation with the Colorado Division of Minerals and Geology (CDMG), Colorado Department of Public Health and Environment (CDPHE), US Forest Service (USFS), the Bureau of Land Management (BLM), Bureau of Reclamation (BOR) and the US Geological Survey (USGS). These agencies collaborated on the environmental problems at abandoned mines. These samples involved the interaction of surface and ground waters with sulfide-bearing rocks, mine workings and surface mine spoils that produce acid solutions charged with heavy metals that are toxic to organisms. In these examples, acid mine drainage from historic mines in Colorado has been approached cooperatively with stakeholders. Each example emphasizes one aspect of the three-stage process. These stages include characterization and prioritization, hydrologic controls and the evaluation of long-term remediation activities.
Address J. Dunn, US Environmental Protection Agency, Region 8, 999 18(th) St., Suite 500, Denver, CO 80202-2466, United States
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Notes Remediating historic mine sites in Colorado; 0434641; United-States; Geobase Approved no
Call Number (up) CBU @ c.wolke @ 17547 Serial 398
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Author Sanders, F.; Rahe, J.; Pastor, D.; Anderson, R.
Title Wetlands treat mine runoff Type Journal Article
Year 1999 Publication Civil Engineering Abbreviated Journal
Volume 69 Issue 1 Pages 53-55
Keywords Reclamation and conservation Groundwater problems and environmental effects geological abstracts: environmental geology (72 14 1) geomechanics abstracts: excavations (77 10 10) abandoned mine acid mine drainage constructed wetland heavy metal remediation United States Montana Blackfoot River
Abstract In the late 1890s, silver, lead and zinc deposits were discovered along the headwaters of the Blackfoot River, northeast of Missoula, Mont. Settlers began mining the metals in earnest, and eventually the mines became known as the Upper Blackfoot Mining Complex (UBMC). Many of the mines were operated long enough to supply metals for World War II weaponry, but after the war the mines were abandoned, and by the 1960s, their orange-tainted runoff began to concern both passersby and state officials. In 1991, the state contacted the current owners of several of those mines-including the Mike Horse and the Anaconda-to negotiate a voluntary cleanup. The American Smelting and Refining Co. (ASARCO) and the Atlantic Richfield Co. (ARCO) agreed to remediate the sites' metal-enriched, moderately to severely acidic drainage, which was discharging into the upper Blackfoot River. As part of effort to reclaim the Mike Horse and Anaconda mines, engineers with McCulley, Frick and Gilman Inc. (MFG), Boulder, Colo., developed an integrated, passive wetland treatment system that will take several years to reach full treatment capacity in the high-elevation environment, but will last for decades. (Constructed and restored wetlands have also been part of the remediation of other UBMC mines, such as the Carbonate and Paymaster mines.) The Mike Horse and Anaconda system, designed to meet National Pollutant Discharge Elimination Systems (NPDES) restrictions, concentrates primarily on zinc and iron and, to a lesser extent, on copper, lead and other metals.
Address F. Sanders, McCulley, Frick and Gilman Inc., Boulder, CO, United States
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ISSN 0885-7024 ISBN Medium
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Notes Wetlands treat mine runoff; 0411276; United-States; Geobase Approved no
Call Number (up) CBU @ c.wolke @ 17551 Serial 256
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Author Benner, S.G.; Blowes, D.W.; Ptacek, C.J.
Title A full-scale porous reactive wall for prevention of acid mine drainage Type Journal Article
Year 1997 Publication Ground Water Monitoring and Remediation Abbreviated Journal
Volume 17 Issue 4 Pages 99-107
Keywords acid mine drainage alkalinity bacteria Canada case studies concentration dissolved materials drainage Eastern Canada ground water mines observation wells Ontario permeability pH pollution porous materials recharge reduction remediation site exploration Sudbury District Ontario sulfate ion surface water waste disposal water pollution Groundwater quality Groundwater problems and environmental effects Pollution and waste management non radioactive geographical abstracts: physical geography hydrology (71 6 11) geomechanics abstracts: excavations (77 10 10) geological abstracts: environmental geology (72 14 2) groundwater protection permeable barrier acid mine drainage aquifer groundwater acid min drainage contamination permeable barrier groundwater protection permeable barrier acid mine drainage aquifer Canada, Ontario, Sudbury, Nickel Rim
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.
Address Dr. S.G. Benner, Earth Sciences Department, University of Waterloo, Waterloo, Ont. N2L 3G1, Canada
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ISSN 1069-3629 ISBN Medium
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Notes Review; A full-scale porous reactive wall for prevention of acid mine drainage; 0337197; United-States 46; file:///C:/Dokumente%20und%20Einstellungen/Stefan/Eigene%20Dateien/Artikel/10621.pdf; Geobase Approved no
Call Number (up) CBU @ c.wolke @ 17555 Serial 67
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