Papers by Keyword: Abandoned Mines

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Authors: A.V. Nazarkina, O.D. Arefieva, T. M. Kadyrova, L. G. Buyanova, E. M. Savenkova
Abstract: Abandonment of «Avangard» Coal Mine and its Flooding Caused the Decrease of Natural Waters Quality and Caused a Threat of that Area’s Pollution. Statistical Analysis Showed that due to Transfusion of Various Horizons Waters, close Dependencies between the Quality of Mine Waters, River/well Waters and Soil Solutions are Observed. Mine Waters are Transforming Not only the Composition of Natural Waters and Wells but have Great Impact on the Composition of Soil Solution. Growing Mineralization of Mine Waters Causes Active Flowing out of Chrome, Copper, Iron, Nitrates, Suspended Matters, Silicon Compounds, Sulfates, Phosphates and Sulfides. as Ph Grows, the Mobility of Chrome, Copper, Nitrates, Silicon Compounds, Sulfates and Phosphates is Decreasing. they are Consolidated in Soil.
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Authors: Lillian Rabelo Lopes, Mônica Cristina Teixeira
Abstract: Ouro Preto/MG/Brazil soils are rich in arsenic containing minerals that once solubilized may contaminate water or food. Arsenic (As) is toxic if ingested or inhaled. Microorganisms and organic matter plays an important role in the dynamics of As in soils and sediments affecting its mobilization. Aims: to study the mobility of arsenic in the presence of organic matter and sulfur reducing bacteria (SRB) and also to obtain some As resistant bacterial cultures. Materials: Soil samples were collected from abandoned gold mines named Old Mine, Chico Rei and Santa Rita. As content in solid samples were in a range of 465 to 1829 mg Kg-1. Soil samples (5 g) were mixed with 35 ml of 2.5 M, CaCl2, stirred (5 min) and allowed to rest at 21.0°C for 1, 30, 60, 90 and 120 days. Other set of experiments were prepared following the previous procedure with some modifications: (i) group 1, flasks with bacterial inoculum (4 ml) from an enrichment of 5 g of soil and 45 ml of liquid medium B Postgate, pH 7.0, incubated at 35°C under anaerobic conditions; (ii) group 2, flasks with (5 g) of organic matter with As (III) adsorptive capacity (powdered chicken feathers - PCF), and (iii) group 3, flasks containing bacterial inoculum and organic matter. Results: As solubility was inversely proportional to time and depends on Fe and Mn contents. The influence of microorganisms on As immobilization was more relevant than the presence of organic matter. Surprisingly, in some cases, As solubility enhanced in the presence of PCF besides its As adsorptive capacity. One microbial consortium adapted to the culturing at pH 5.0 was obtained and this is an interesting feature considering the acid pH of the studied arsenic soils. Indigenous bacteria phenotypically similar to SRB may contribute to As immobilization in natural or impacted environment.
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Authors: Seong Jin Joe, Masatoshi Sakoda, Tadashi Chida, Yoshiharu Kida, Hidekatsu Nakamura, Muneyuki Tamura
Abstract: Bioleaching studies have been conducted to obtain bacteria having a high ability to dissolve copper from chalcopyrite. For these studies, samples of mine drainage water which contain high concentrations of copper or iron ions in several abandoned mines in Japan were used to inoculate enrichment cultures on 0.16 M ferrous iron in the absence of chalcopyrite concentrate. Afterwards, these were accumulated and supplied to shaking-flask bioleaching tests on chalcopyrite concentrate. Copper dissolution rates were measured in chalcopyrite leaching experiments and compared with those using cell-free ferrous/ferric media. The copper dissolution rate in ferrous sulphate medium was higher than that in ferric sulphate medium. Moreover, tests in the presence of bacteria showed even an higher copper dissolution rate.
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