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Michaud, L. H. (1994). Recent technology related to the treatment of acid drainage. Earth and Mineral Sciences, 63(3), 53–55.
Abstract: The generation of acid mine drainage is a serious environmental problem associated with coal mining. The chemistry of acid mine drainage is outlined. The prevention and minimization of acid mine drainage formation is examined. The in situ inhibition and remediation of acid mine drainage is described. Methods for the passive treatment of acid mine drainage after formation are discussed. The design of treatment systems is considered. -P.M.Taylor
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Srivastave, A., & Chhonkar, P. K. (2000). Amelioration of coal mine spoils through fly ash application as liming material. J. Ind. Res., 59(4), 309–313.
Abstract: The feasibility of fly ash as compared to lime to ameliorate the low pH of acidic coal mine spoils under controlled pot culture conditions are reported using Sudan grass (Sorghum studanens) and Oats (Avena sativa) as indicator crops. It is observed that at all levels of applications, fly ash and lime significantly increase the pH of mine spoils, available phosphorus, exchangeable potassium, available sulphur and also uptake of phosphorus, potassium, sulphur and oven-dried biomass of both these test crops. The fly ash significantly decreases the bulk density of coal mine spoils, but, there is no effect on bulk density due to lime application. However, when the spoils are amended with either fly ash or lime, the root growth occurs throughout the material. Fly ash and lime do not cause elemental toxicities to the plants as evidenced from the dry matter production by the test crops. The results indicate that fly ash to be a potential alternative to lime for treating acidic coal mine spoils.
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Mustikkamaki, U. - P. (2000). Metallipitoisten vesien biologisesta kasittelysta Outokummun kaivoksilla. Metal content treated with biological methods at the Outokummun operation. Vuoriteollisuus = Bergshanteringen, 58(1), 44–47.
Abstract: Acid mine drainage (AMD) is one of the most serious environmental problems in the metal-mining industry. AMD is formed by the chemical and bacterial oxidation of sulphide minerals, and it is characterized by low pH values and high sulphate and metals content. The most common method to treat AMD is chemical neutralization. The chemical treatment requires high capital and operating costs and its use is problematic at the closed mines sites. Outokumpu has studied and used sulphate reducing bacteria (SRB) as an alternative method for the treatment of AMD. SRB existing in many natural anaerobic aqueous environments can reduce sulphate to sulphide which precipitates metals as extremely insoluble metal sulphides. Full scale experiments were begun in summer 1995 in the Ruostesuo open pit (depth 46 m) by adding liquid manure as a source of bacteria and press-juice as a growth substrate. The average Zn content of the whole column has decreased from 3,5 mg/l to 0,8 mg/l and below 25 m zinc is 0 mg/l. Similar results have been reached with nickel in the Kotalahti old nickel mine, where bacteria were brought in 1996. We have found that the same bacterial mechanism acts in peat-limestone filters, which Outokumpu has built at several mine sites since 1993.
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Foucher, S., Battaglia-Brunet, F., Ignatiadis, I., & Morin, D. (2001). Treatment by sulfate-reducing bacteria of Chessy acid-mine drainage and metals recovery. Chemical Engineering Science, 56(4), 1639–1645.
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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Sato, D., & Tazaki, K. (2000). Calcification treatment of mine drainage and depositional formula of heavy metals. Chikyu Kagaku = Earth Science, 54(5), 328–336.
Abstract: Depositional formula of heavy metals after disposal of the mine drainage from the Ogoya Mine in Ishikawa Prefecture, Japan, was mineralogically investigated. Strong acidic wastewater (pH 3.5) from pithead of the mine contains high concentration of heavy metals. In this mine, neutralizing coagulation treatment is going on by slaked lime (calcium hydroxides: Ca(OH) (sub 2) ). Core samples were collected at disposal pond to which the treated wastewater flows. The core samples were divided into 44 layers based on the color variation. The mineralogical and chemical compositions of each layer were analyzed by an X-ray powder diffractometer (XRD), an energy dispersive X-ray fluorescence analyzer (ED-XRF) and a NCS elemental analyzer. The upper parts are rich in brown colored layers, whereas discolored are the deeper parts. The color variation is relevant to Fe concentration. Brown colored core sections are composed of abundant hydrous ferric oxides with heavy metals, such as Cu, Zn, and Cd. On the other hand, S concentration gradually increases with depth. XRD data indicated that calcite decreases with increasing depth, and ettringite is produced at the deeper parts. Cd concentration shows similar vertical profile to those of calcite and ettringite. The results revealed that hydrous ferric oxides, calcite and ettringite are formed on deposition, whereby incorporating the heavy metals.
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