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Author (down) Gatzweiler, R. url  openurl
  Title Cover design for radioactive and AMD-producing mine waste in the Ronneburg area, Eastern Thuringia Type Journal Article
  Year 2001 Publication Waste Management Abbreviated Journal  
  Volume 21 Issue 2 Pages 175-184  
  Keywords mine water treatment  
  Abstract At the former uranium mining site of Ronneburg, large scale underground and open pit mining for nearly 40 years resulted in a production of about 113 000 tonnes of uranium and about 200 million cubic metres of mine waste. In their present state, these materials cause risks to human health and strong environmental impacts and therefore demand remedial action. The remediation options available are relocation of mine spoil into the open pit and on site remediation by landscaping/contouring, placement of a cover and revegetation. A suitable vegetated cover system combined with a surface water drainage system provides long-term stability against erosion and reduces acid generation thereby meeting the main remediation objectives which are long-term reduction of radiological exposure and contaminant emissions and recultivation. The design of the cover system includes the evaluation of geotechnical, radiological, hydrological, geochemical and ecological criteria and models. The optimized overall model for the cover system has to comply with general conditions as, e.g. economic efficiency, public acceptance and sustainability. Most critical elements for the long-term performance of the cover system designed for the Beerwalde dump are the barrier system and its long-term integrity and a largely self-sustainable vegetation. (C) 2001 Elsevier Science Ltd. All rights reserved.  
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  Notes Cover design for radioactive and AMD-producing mine waste in the Ronneburg area, Eastern Thuringia; Wos:000166676900008; Times Cited: 0; ISI Web of Science Approved no  
  Call Number CBU @ c.wolke @ 17047 Serial 127  
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Author (down) Foucher, S.; Battaglia-Brunet, F.; Ignatiadis, I.; Morin, D. url  openurl
  Title Treatment by sulfate-reducing bacteria of Chessy acid-mine drainage and metals recovery Type Journal Article
  Year 2001 Publication Chemical Engineering Science Abbreviated Journal  
  Volume 56 Issue 4 Pages 1639-1645  
  Keywords Acid mine drainage Sulfate-reducing bacteria Sulfide precipitation Hydrogen transfer Fixed bed column reactor  
  Abstract Acid-mine drainage can contain high concentrations of heavy metals and release of these contaminants into the environment is generally avoided by lime neutralization. However, this classical treatment is expensive and generates large amounts of residual sludge. The selective precipitation of metals using H2S produced biologically by sulfate-reducing bacteria has been proposed as an alternative process. Here, we report on experiments using real effluent from the disused Chessy-les-Mines mine-site at the laboratory pilot scale. A fixed-bed bioreactor, fed with an H2/CO2 mixture, was used in conjunction with a gas stripping column. The maximum rate of hydrogen transfer in the bioreactor was determined before inoculation. kLa was deduced from measurements of O2 using Higbie and Danckwert's models which predict a dependence on diffusivity. The dynamic method of physical absorption and desorption was used. The maximum rate of H2 transfer suggests that this step should not be a limiting factor. However, an increase in H2 flow rate was observed to induce an increase in sulfate reduction rate. For the precipitation step, the gas mixture from the bioreactor was bubbled into a stirred reactor fed with the real effluent. Cu and Zn could be selectively recovered at pH=2.8 and pH=3.5, respectively. Other impurities such as Ni and Fe could also be removed at pH=6 by sulfide precipitation. Part of the outlet stream from the bioreactor was used to regulate and maintain the pH during sulfide precipitation by feeding the outlet stream back into the bioreactor. The replacement of synthetic medium with real effluent had a positive effect on sulfate reduction rate which increased by 30-40%. This improvement in bacterial efficiency may be related to the large range of oligo-elements provided by the mine-water. The maximum sulfate reduction rate observed with the real effluent was 200 mgl-1 h-1, corresponding to a residence time of 0.9 day. A preliminary cost estimation based on a treatment rate of 5 m3 h-1 of a mine effluent containing 5 gl-1 SO42- is presented.  
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  ISSN 0009-2509 ISBN Medium  
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  Notes Feb.; Treatment by sulfate-reducing bacteria of Chessy acid-mine drainage and metals recovery; file:///C:/Dokumente%20und%20Einstellungen/Stefan/Eigene%20Dateien/Artikel/10064.pdf; Science Direct Approved no  
  Call Number CBU @ c.wolke @ 10064 Serial 54  
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Author (down) Fernandez Rubio, R. openurl 
  Title Un recurso valioso las aguas de mina. A valuable resource, mine waters Type Journal Article
  Year 2001 Publication Industria y Mineria Abbreviated Journal  
  Volume 345 Issue Pages 14-22  
  Keywords acid mine drainage; Africa; aquifers; case studies; East Africa; Europe; ground water; hydrogeochemical exploration; hydrogeological survey; Iberian Peninsula; injection; mining; mining geology; open-pit mining; pollution; Portugal; Southern Europe; surface mining; surface water; underground mining; water supply; water treatment; Zambia 21, Hydrogeology  
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  ISSN 1137-8042 ISBN Medium  
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  Notes Un recurso valioso las aguas de mina. A valuable resource, mine waters; 374358-2; illus. Spain (ESP); GeoRef In Process; Spanish Approved no  
  Call Number CBU @ c.wolke @ 5784 Serial 381  
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Author (down) Evangelou, V.P. url  openurl
  Title Pyrite microencapsulation technologies: Principles and potential field application Type Journal Article
  Year 2001 Publication Ecological Engineering Abbreviated Journal  
  Volume 17 Issue 2-3 Pages 165-178  
  Keywords mine water treatment Acid mine drainage Acidity Alkalinity Amelioration Coating Oxidation Surface reactions  
  Abstract 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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  ISSN 0925-8574 ISBN Medium  
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  Notes July 01; Pyrite microencapsulation technologies: Principles and potential field application; file:///C:/Dokumente%20und%20Einstellungen/Stefan/Eigene%20Dateien/Artikel/10063.pdf; Science Direct Approved no  
  Call Number CBU @ c.wolke @ 10063 Serial 37  
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Author (down) Dempsey, B.A.; Jeon, B.-H. url  openurl
  Title Characteristics of sludge produced from passive treatment of mine drainage Type Journal Article
  Year 2001 Publication Geochem.-Explor. Environ. Anal. Abbreviated Journal  
  Volume 1 Issue 1 Pages 89-94  
  Keywords acid mine drainage; aerobic environment; anaerobic environment; Appalachian Plateau; Appalachians; carbonate rocks; coagulation; compressibility; decontamination; density; drainage; filtration; geochemistry; Howe Bridge; Jefferson County Pennsylvania; limestone; mining geology; North America; passive systems; Pennsylvania; pH; pollution; ponds; rates; reclamation; sedimentary rocks; settling; sludge; slurries; suspended materials; United States; viscosity; wet packing density; wetlands; zeta-potential 22, Environmental geology  
  Abstract In the 1994 paper by Brown, Skousen & Renton it was argued that settleability and wet-packing density were the most important physical characteristics of sludge from treatment of mine drainage. These characteristics plus zeta-potential, intrinsic viscosity, specific resistance to filtration, and coefficient of compressibility were determined for several sludge samples from passive treatment sites and for several sludge samples that were prepared in the laboratory. Sludge from passive systems had high packing density, low intrinsic viscosity, low specific resistance to filtration and low coefficient of compressibility compared to sludge that was produced after addition of NaOH.  
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  ISSN 1467-7873 ISBN Medium  
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  Notes Feb.; Characteristics of sludge produced from passive treatment of mine drainage; 2002-008382; References: 29; illus. incl. 5 tables United Kingdom (GBR); GeoRef; English Approved no  
  Call Number CBU @ c.wolke @ 5734 Serial 57  
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