| Records |
| Author |
Sheoran, A.S.; Sheoran, V. |
| Title |
Heavy metal removal mechanism of acid mine drainage in wetlands: A critical review |
Type |
Journal Article |
| Year |
2006 |
Publication |
Minerals Engineering |
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Volume  |
19 |
Issue |
2 |
Pages |
105-116 |
| Keywords |
Acid mine drainage Metal removal mechanism Wetlands |
| Abstract |
Acid mine drainage (AMD) is one of the most significant environmental challenges facing the mining industry worldwide. Water infiltrating through the metal sulphide minerals, effluents of mineral processing plants and seepage from tailing dams becomes acidic and this acidic nature of the solution allows the metals to be transported in their most soluble form. The conventional treatment technologies used in the treatment of acid mine drainage are expensive both in terms of operating and capital costs. One of the methods of achieving compliance using passive treatment systems at low cost, producing treated water pollution free, and fostering a community responsibility for acid mine water treatment involves the use of wetland treatment system. These wetlands absorb and bind heavy metals and make them slowly concentrated in the sedimentary deposits to become part of the geological cycle. In this paper a critical review of the heavy metal removal mechanism involving various physical, chemical and biological processes, which govern wetland performance, have been made. This information is important for the siting and use of wetlands for remediation of heavy metals. |
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Heavy metal removal mechanism of acid mine drainage in wetlands: A critical review; Science Direct |
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CBU @ c.wolke @ 17252 |
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41 |
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| Author |
Adam, K. |
| Title |
Solid wastes management in sulphide mines: From waste characterisation to safe closure of disposal sites |
Type |
Journal Article |
| Year |
2003 |
Publication |
Minerals and Energy Raw Materials Report |
Abbreviated Journal |
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| Volume |
18 |
Issue |
4 |
Pages |
25-35 |
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Waste Management and Pollution Policy Pollution and waste management non radioactive geographical abstracts: human geography environmental planning (70 11 5) geological abstracts: environmental geology (72 14 2) waste disposal waste management solid waste mining industry acid mine drainage Europe Eurasia |
| Abstract |
Environmentally compatible Waste Management schemes employed by the European extractive industry for the development of new projects, and applied in operating sulphide mines, are presented in this study. Standard methodologies used to assess the geotechnical and geochemical properties of the solid wastes stemming from mining and processing of sulphidic metal ores are firstly given. Based on waste properties, the measures applied to ensure the environmentally safe recycling and disposal of sulphidic wastes are summarised. Emphasis is given on the novel techniques developed to effectively prevent and mitigate the acid drainage phenomenon from sulphidic mine wastes and tailings. Remediation measures taken to minimise the impact from waste disposal sites in the post-closure period are described. |
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K. Adam, ECHMES Ltd, Mikras Asias 40-42, Athens 11527, Greece echmes@otenet.gr |
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1404-1049 |
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Solid wastes management in sulphide mines: From waste characterisation to safe closure of disposal sites; 2582509; Norway 25; Geobase |
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CBU @ c.wolke @ 17510 |
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492 |
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'Green' company offers desalination technology |
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Journal Article |
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1998 |
Publication |
Water Sewage and Effluent |
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18 |
Issue |
4 |
Pages |
9-11 |
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Groundwater problems and environmental effects geomechanics abstracts: excavations (77 10 10) acid mine drainage environmental effect mine drainage |
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Water and wastewater treatment activities, projects and capabilities of South African environmental engineering specialist Envig are detailed. The company, as part of the Weir Wesgarth Consortium, has pre-qualified for the major Namibian Water Supply Project, one of the largest of its kind to date in southern Africa. This project involves the desalination of seawater to meet increasing water demand and shortfalls. Envig, if awarded the contract, would be involved in construction of three or four reverse osmosis or mechanical vapour compression sea water desalination plants and associated infrastructure. The company is also involved in a mine water desalination project at the Eskom Tutuka Power Station. A reverse osmosis plant using low fouling maintenance is being installed to deal with acid mine drainage water. Details of the design and operation of this plant are given. |
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0257-8700 |
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'Green' company offers desalination technology; 0432290; South-Africa; Geobase |
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CBU @ c.wolke @ 17548 |
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496 |
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| Author |
Evangelou, V.P. |
| Title |
Pyrite microencapsulation technologies: Principles and potential field application |
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Journal Article |
| Year |
2001 |
Publication |
Ecological Engineering |
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| Volume |
17 |
Issue |
2-3 |
Pages |
165-178 |
| Keywords |
mine water treatment Acid mine drainage Acidity Alkalinity Amelioration Coating Oxidation Surface reactions |
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In nature, pyrite is initially oxidized by atmospheric O2, releasing acidity and Fe2+. At pH below 3.5, Fe2+ is rapidly oxidized by T. ferrooxidans to Fe3+, which oxidizes pyrite at a much faster rate than O2. Commonly, limestone is used to prevent pyrite oxidation. This approach, however, has a short span of effectiveness because after treatment the surfaces of pyrite particles remain exposed to atmospheric O2 and oxidation continuous abiotically. Currently, a proposed mechanism for explaining non-microbial pyrite oxidation in high pH environments is the involvement of OH- in an inner-sphere electron-OH exchange between pyrite/surface-exposed disulfide and pyrite/surface-Fe(III)(OH)n3-n complex and/or formation of a weak electrostatic pyrite/surface-CO3 complex which enhances the chemical oxidation of Fe2+. The above infer that limestone application to pyritic geologic material treats only the symptoms of pyrite oxidation through acid mine drainage neutralization but accelerates non-microbial pyrite oxidation. Therefore, only a pyrite/surface coating capable of inhibiting O2 diffusion is expected to control long-term oxidation and acid drainage production. The objective of this study was to examine the feasibility in controlling pyrite oxidation by creating, on pyrite surfaces, an impermeable phosphate or silica coating that would prevent either O2 or Fe3+ from further oxidizing pyrite. The mechanism underlying this coating approach involves leaching mine waste with a coating solution composed of H2O2 or hypochlorite, KH2PO4 or H4SiO4, and sodium acetate (NaAC) or limestone. During the leaching process, H2O2 or hypochlorite oxidizes pyrite and produces Fe3+ so that iron phosphate or iron silicate precipitates as a coating on pyrite surfaces. The purpose of NaAC or limestone is to eliminate the inhibitory effect of the protons (produced during pyrite oxidation) on the precipitation of iron phosphate or silicate and to generate iron-oxide pyrite coating, which is also expected to inhibit pyrite oxidation. The results showed that iron phosphate or silicate coating could be established on pyrite by leaching it with a solution composed of: (1) H2O2 0.018-0.16 M; (2) phosphate or silicate 10-3 to 10-2 M; (3) coating-solution pH [approximate]5-6; and (4) NaAC as low as 0.01 M. Leachates from column experiments also showed that silicate coatings produced the least amount of sulfate relative to the control, limestone and phosphate treatments. On the other hand, limestone maintained the leachate near neutral pH but produced more sulfate than the control. |
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0925-8574 |
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July 01; Pyrite microencapsulation technologies: Principles and potential field application; file:///C:/Dokumente%20und%20Einstellungen/Stefan/Eigene%20Dateien/Artikel/10063.pdf; Science Direct |
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no |
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CBU @ c.wolke @ 10063 |
Serial |
37 |
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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 |
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| 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 |
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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. |
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Dr. S.G. Benner, Earth Sciences Department, University of Waterloo, Waterloo, Ont. N2L 3G1, Canada |
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1069-3629 |
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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 |
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CBU @ c.wolke @ 17555 |
Serial |
67 |
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