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Author Mitchell, P.; Wheaton, A.
Title From environmental burden to natural resource; new reagents for cost-effective treatment of, and metal recovery from, acid rock drainage Type Book Chapter
Year 1999 Publication Sudbury '99; Mining and the environment II; Conference proceedings Abbreviated Journal
Volume Issue Pages
Keywords (up) acid mine drainage Bunker Hill Mine cost decontamination Idaho metal ores mines mitigation natural resources pollution reagents recovery Shoshone County Idaho sludge United States zinc ores 22 Environmental geology 27A Economic geology, geology of ore deposits
Abstract Acid rock drainage remains the greatest environmental issue faced by the mining sector and as the new millennium approaches, low capital/operating cost treatments remain elusive. Therefore as part of an ongoing process to develop a leading edge, innovative and cost-effective approach, pilot trials were conducted by KEECO in collaboration with the New Bunker Hill Mining Company on a substantial and problematic metal-contaminated acid flow, emanating from underground workings at the Bunker Hill Mine, Idaho. The aims of the work were fourfold. First to assess the capacity of KEECO's unique Silica Micro Encapsulation (SME) reagents and associated dosing systems to cost-effectively decontaminate the acid flow to stringent standards set by the U.S. Environmental Protection Agency (USEPA), where alternative and standard technologies had failed. Second, to demonstrate that treatment using a compact system suitable for underground installation. Third, to demonstrate that the treatment sludge had enhanced chemical stability in absolute terms and relative to standard approaches. Fourth, to examine the potential for resource recovery via sequential precipitation. Although the focus to date has been the development of a cost-effective treatment technology, the latter aim was considered essential in light of the growing pressure on all industrial sectors to develop tools for environmentally sustainable economic growth and the growing demands of stakeholders for improved resource usage and recycling. Two phases of work were undertaken: a laboratory-based scoping exercise followed by installation within the mine workings of a compact reagent delivery/shear mixing unit capable of treating the full flow of 31 L s (super -1) . At a dose rate of 2.0 g L (super -1) (equivalent to a final treated water pH range of 7-9), the SME reagent KB-1 reduced metal concentrations to levels approaching the U.S. Drinking Water Standards, which no other treatment piloted at the site had achieved. Based on the USEPA's Toxicity Characteristic Leaching Procedure, the sludge arising from the treatment was classified as non-hazardous. Operating costs compared favourably with those of lime use, while estimated capital costs were considerably lower due to the compact nature of the reagent delivery system and the rapid settling characteristics of the treatment sediment. Resource recovery was attempted using a two-stage selective precipitation approach. The first stage involved pH adjustment to 5.5 (by addition of 1.5 g L (super -1) of KB-1) to produce a sludge enriched in aluminium, iron and manganese, with lesser amounts of arsenic, nickel, lead and zinc. Further KB-1 addition to a total of 2.1 g L (super -1) generated sludge enriched in zinc (33% by dry weight), demonstrating that resource recovery is theoretically feasible. Further work on downstream processing is required, although it is considered that the most likely route for zinc metal recovery will be high temperature/pressure due to the chemically inert nature of the zinc-rich sediment.
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Publisher Place of Publication Editor Goldsack, D.E.; Belzile, N.; Yearwood, P.; Hall, G.J.
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ISSN ISBN 0886670470 Medium
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Notes From environmental burden to natural resource; new reagents for cost-effective treatment of, and metal recovery from, acid rock drainage; GeoRef; English; 2000-048642; Sudbury '99; Mining and the environment II, Sudbury, ON, Canada, Sept. 13-17, 1999 References: 3; illus. incl. 5 tables Approved no
Call Number CBU @ c.wolke @ 16593 Serial 296
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Author Mitchell, P.; Rybock, J.; Wheaton, A.
Title Treatment and prevention of ARID using silica micro encapsulation Type Book Chapter
Year 1999 Publication Proceedings of the 16th annual National meeting of the American Society for Surface Mining and Reclamation; Mining and reclamation for the next millennium Abbreviated Journal
Volume Issue Pages 657-661
Keywords (up) acid mine drainage Bunker Hill Mine Idaho mines pollution Shoshone County Idaho United States water treatment 22, Environmental geology
Abstract In response to the known drawbacks of liming and the ever-increasing regulatory demands on the mining industry, KEECO has developed a silica micro encapsulation (SME) process. SME is a cost-effective, high performance reagent that is utilized in conjunction with simple chemical delivery systems. By encapsulating metals in a silica matrix formation and rapidly precipitating them into a sand-like sludge, it offers all the advantages of liming without the negative drawbacks. Utilizing an injection technique via a high shear mixing device, a slurry from of the SME product called KB-1 (super TM) was applied to ARD at the Bunker Hill Mine in Idaho and to ARD pumped from collection ponds at a remote mine site in the Sierra Nevada Mountains. Flow rates at both sites ranged from 500 to 800 gallons per minute. Treated water from the Bunker Hill Mine operation achieved the site's NPDES criteria for all evaluated metals and U.S. Drinking Water quality for arsenic, cadmium, chromium, lead and zinc with a dosage rate of 1.34 grams KB-1 (super TM) per liter. Treated water from the Sierra Nevada project focused on the control of aluminum, arsenic, copper, iron and nickel. All water samples displayed a >99.5% reduction in these metals, as well as an 84%-87% reduction in the concentration of sulfate. Testing on sludge generated from both operations achieved TCLP Action Limits. The SME process is currently under evaluation as a means to coat the pyrite surfaces of newly generated mine tailings to prevent oxidation and future acid generation.
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Publisher Place of Publication 16 Editor Bengson, S.A.; Bland, D.M.
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Notes Treatment and prevention of ARID using silica micro encapsulation; GeoRef; English; 2001-047986; 16th annual National meeting of the American Society for Surface Mining and Reclamation, Scottsdale, AZ, United States, Aug. 13-19, 1999 2 tables Approved no
Call Number CBU @ c.wolke @ 16602 Serial 297
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Author Ketellapper, V.L.; Williams, L.O.; Bell, R.S.; Cramer, M.H.
Title The control of acid mine drainage at the Summitville Mine Superfund Site Type Book Chapter
Year 1996 Publication Proceedings of the Symposium on the Application of Geophysics to Environmental and Engineering Problems (SAGEEP), vol.1996 Abbreviated Journal
Volume Issue Pages 303-311
Keywords (up) acid mine drainage Colorado Del Norte Colorado gold ores metal ores mines mining mining geology open-pit mining pollutants pollution remediation Rio Grande County Colorado Summitville Mine Superfund sites surface mining United States water quality 22, Environmental geology
Abstract The Summitville Mine Superfund Site is located about 25 miles south of Del Norte, Colorado, in Rio Grande County. Occurring at an average elevation of 11,500 feet in the San Juan Mountain Range, the mine site is located two miles east of the Continental Divide. Mining at Summitville has occurred since 1870. The mine was most recently operated by Summitville Consolidated Mining Company, Inc. (SCMCI) as an open pit gold mine with extraction by means of a cyanide leaching process. In December of 1992, SCMCI declared bankruptcy and vacated the mine site. At that time, the US Environmental Protection Agency (EPA) took over operations of the water treatment facilities to prevent a catastrophic release of cyanide and metal-laden water from the mine site. Due to high operational costs of water treatment (approximately $50,000 per day), EPA established a goal to minimize active water treatment by reducing or eliminating acid mine drainage (AMD). All of the sources of AMD generation on the mine site were evaluated and prioritized. Of the twelve areas identified as sources of AMD, the Cropsy Waste Pile, the Summitville Dam Impoundment, the Beaver Mud Dump, the Reynolds and Chandler adits, and the Mine Pits were consider to be the most significant contributors to the generation of metal-laden acidic (low pH) water. A two part plan was developed to control AMD from the most significant sources. The first part was initiated immediately to control AMD being released from the Site. This part focused on improving the efficiency of the water treatment facilities and controlling the AMD discharges from the mine drainage adits. The discharges from the adits was accomplished by plugging the Reynolds and Chandler adits. The second part of the plan was aimed at reducing the AMD generated in groundwater and surface water runoff from the mine wastes. A lined and capped repository located in the mine pits for acid generating mining waste and water treatment plant sludge was found to be the most feasible alternative. Beginning in 1993, mining wastes which were the most significant sources of AMD were being excavated and placed in the Mine Pits. In November 1995, all of the waste from these sources had been excavated and placed in the the Mine Pits. This paper discusses EPA's overall approach to stabilize on-site sources sufficiently such that aquatic, agricultural, and drinking water uses in the Alamosa watershed are restored and/or maintained with minimal water treatment.
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Notes The control of acid mine drainage at the Summitville Mine Superfund Site; GeoRef; English; 2002-027195; Symposium on the Application of geophysics to engineering and environmental problems, Keystone, CO, United States, April 28-May 2, 1996 References: 11; illus. incl. geol. sketch map Approved no
Call Number CBU @ c.wolke @ 16654 Serial 334
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Author Norton, P.J.
Title The Control of Acid Mine Drainage with Wetlands Type Journal Article
Year 1992 Publication Mine Water Env. Abbreviated Journal
Volume 11 Issue 3 Pages 27-34
Keywords (up) acid mine drainage construction chemistry artificial wetlands pollution control performance evaluation coal mines pollution control and prevention
Abstract The recent increases in environmental legislation, especially in the USA'have meant that there is a need on behalf of the mining companies for more judicious operational planning and more thorough restoration techniques in order to reduce costs and prevent violation of the smctly enforced regulations. Water pollution is probably the greatest problem and many less enlightened operators, especially for example, in surface coal milling in Pennsylvania, have been forced into liquidation after having been unable to meet the severe restrictions on Acid Mine Drainage (AMD). The problems of AMD are also inherent in most forms of metalliferous and coal mining and also in some types of aggregate quarrying. As excavations go deeper in search of ever diminishing reserves then they are more likely to encounter groundwater which can become polluted if insufficient care is not taken. It is to be expected that the laws will also become more severe than they are at present in Europe and methods of treatment of AMD will need to be developed that are more efficient than the costly chemical methods currently used. Research by the author and others into the source of AMD pollution and its treatment with engineered wetlands and other operational methods are discussed in the paper. The methods have- the distinct benefit that they are cheap to install, are cost effective over a long period with the minimum of supervision and are environmentally acceptable to the planning and regulatory authorities.
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Notes The Control of Acid Mine Drainage with Wetlands; 1; 1 Abb.; AMD ISI | Wolkersdorfer Approved no
Call Number CBU @ c.wolke @ 17401 Serial 284
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Author Taylor, J.; Waters, J.
Title Treating ARD; how, when, where and why Type Journal Article
Year 2003 Publication Mining Environmental Management Abbreviated Journal
Volume 11 Issue 3 Pages 6-9
Keywords (up) acid mine drainage; acid rock drainage; acidification; alkalinity; carbonate rocks; chemical properties; chemical reactions; coal; disposal barriers; economics; flocculation; ground water; heavy metals; human activity; ion exchange; limestone; mines; oxidation; oxides; permeability; pollution; porosity; pyrolusite; remediation; sedimentary rocks; surface water; waste disposal; waste management; water pollution; water treatment; wetlands 22, Environmental geology
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ISSN 0969-4218 ISBN Medium
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Notes Treating ARD; how, when, where and why; 2004-045038; References: 8; illus. incl. 2 tables United Kingdom (GBR); GeoRef; English Approved no
Call Number CBU @ c.wolke @ 5528 Serial 225
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