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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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Corporate Author Thesis
Publisher Place of Publication Editor Goldsack, D.E.; Belzile, N.; Yearwood, P.; Hall, G.J.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 0886670470 Medium
Area Expedition Conference
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 Herbert, R.B., Jr.; Benner, S.G.; Blowes, D.W.
Title Reactive barrier treatment of groundwater contaminated by acid mine drainage; sulphur accumulation and sulphide formation Type Book Chapter
Year 1998 Publication Groundwater Quality: Remediation and Protection Abbreviated Journal
Volume Issue Pages 451-457
Keywords (up) acid mine drainage Canada chemical analysis contaminant plumes Eastern Canada ground water hydraulic conductivity hydrolysis Nickel Rim Mine Ontario pH pollution porosity pyrrhotite remediation sample preparation Sudbury Basin sulfides sulfur tailings water pollution 22, Environmental geology
Abstract A permeable reactive barrier was installed in August 1995 at the Nickel Rim Mine near Sudbury, Ontario, Canada, for the passive remediation of groundwater contaminated with acid mine drainage. The reactive component of the barrier consists of a mixture of municipal and leaf compost and wood chips: the organic material promotes bacterially-mediated sulphate reduction. Hydrogen sulphide, a product of sulphate reduction, may then complex with aqueous ferrous iron and precipitate as iron sulphide. This study presents the solid phase sulphur chemistry of the reactive wall after two years of operation, and discusses the formation and accumulation of iron sulphide minerals in the reactive material. The results from the solid-phase chemical analysis of core samples indicate that there is an accumulation of reduced inorganic sulphur in the reactive wall, with levels reaching 190 mu mol g (super -1) (dry weight) by July 1997.
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Publisher IAHS-AISH Publication, vol.250 Place of Publication Editor Herbert, M.; Kovar, K.
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Series Editor Series Title Abbreviated Series Title
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ISSN ISBN 1901502554 Medium
Area Expedition Conference
Notes Reactive barrier treatment of groundwater contaminated by acid mine drainage; sulphur accumulation and sulphide formation; GeoRef; English; 1999-065115; GQ 98 conference, Tubingen, Federal Republic of Germany, Sept. 21-24, 1998 References: 15; illus. Approved no
Call Number CBU @ c.wolke @ 16621 Serial 65
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Author Benzaazoua, M.; Bussiere, B.
Title Desulphurization of tailings with low neutralizing potential; kinetic study and flotation modeling 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 chemical properties chemical reactions environmental analysis environmental effects experimental studies flotation geochemistry kinetics laboratory studies mathematical models neutralization pH pollution sulfur tailings 22 Environmental geology 02A General geochemistry
Abstract Environmental desulphurization is an attractive alternative for acid generating tailings management as demonstrated during the last few years. In fact, such process placed at the end of the primary treatment circuit allows to reduce greatly the amount of problematic tailings by concentrating the sulphidic fraction. Moreover, the desulphurized tailings (non-acid generating) have the geotechnical and environmental properties for being used as fine material in a cover with capillary barrier effects. To produce desulphurized tailings, non selective froth flotation is the most adapted method as shown in many previous works. Desulphurization level is fixed by tailings sulphur content (or sulphide content) and neutralization potential NP. The final residue should have enough NP to compensate for his acid generating potential AP. In this paper, the authors present the results of laboratory tests conducted in Denver cells for studying the sulphide flotation kinetics of four mine tailings which are characterized by a weak neutralization potential (under 37 kg CaCO (sub 3) /t). Tailings 1, 2, 3 and 4 contain respectively 5.27, 10, 4.25 and 16.9 sulphur Wt. %. Tailings 1 and 2 are cyanide free and are well floated at pH around 11 by using amyl xanthate as collector. Collector dosage was optimized for these tailings and the results show that Tailing 2 need more collector. However, Tailings 3 and 4, which come from a gold cyanidation process, could not provide good sulphide recovery with xanthate collector because of the pyrite depression. To overcome this problem, amine acetate was used successfully but induces important entrainment. The consumption of this collector was also optimized. The results of kinetic tests and collector dosage were combined and modeled to establish relationships which allow to estimate the desulphurization performances.
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Corporate Author Thesis
Publisher Place of Publication Editor Goldsack, D.; Belzile, N.; Yearwood, P.; Hall, G.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 0886670470 Medium
Area Expedition Conference
Notes Desulphurization of tailings with low neutralizing potential; kinetic study and flotation modeling; GeoRef; English; 2002-060841; Sudbury '99; Mining and the environment II--Sudbury '99; L'exploitation miniere et l'environnement, Sudbury, ON, Canada, Sept. 13-17, 1999 References: 26; illus. incl. 5 tables Approved no
Call Number CBU @ c.wolke @ 16572 Serial 452
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Author Evangelou, V.P.
Title Potential microencapsulation of pyrite by artificial inducement of FePO (sub 4) coatings Type Book Chapter
Year 1994 Publication Special Publication – United States. Bureau of Mines, Report: BUMINES-SP-06B-94 Abbreviated Journal
Volume Issue Pages 96-103
Keywords (up) acid mine drainage chemical reactions leaching oxidation pollutants pollution pyrite remediation sulfides tailings theoretical studies waste disposal weathering rinds 22, Environmental geology
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Series Editor Series Title Proceedings of the International land reclamation and mine drainage conference and Third international conference on The abatement of acidic drainage; Volume 2 of 4; Mine drainage Abbreviated Series Title
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ISSN ISBN Medium
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Notes Potential microencapsulation of pyrite by artificial inducement of FePO (sub 4) coatings; GeoRef; English; 2007-045209; International land reclamation and mine drainage conference; International conference on The abatement of acidic drainage, Pittsburgh, PA, United States, April 24-29, 1994 References: 11; illus. Approved no
Call Number CBU @ c.wolke @ 16711 Serial 386
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