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Showing 1 to 20 of 26 for “"acid rock drainage"”.
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Quantifying texture for acid rock drainage characterisation and prediction
… host of environmental problems. One of these is acid rock drainage (ARD), which forms through a complex series of acid formation (mainly via sulfide oxidation), neutralisation (primarily by carbonates) and gangue mineral dissolution reactions in waste rock and tailings storage piles. The …
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Predicting the time related generation of acid rock drainage from mine waste: a copper case study
The mining and beneficiation of coal and hard rock ores generates large volumes of sulphidic waste that may oxidise in the presence of oxygen and result in the generation of acid rock drainage (ARD). In order to effectively manage the long term effects of ARD, there is a need to reliably quantify …
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An integrated approach for the mitigation of acid rock drainage (ARD) associated with pyrrhotite in nickel deposits
… (DETA and TETA) has only been explored on waste rock and pristine pyrrhotite. Furthermore, studies of the mechanism of oxidation of pyrrhotite have observed the formation of a hydrophilic ferric oxyhydroxide layer which enables depression of pyrrhotite during flotation. This layer has been …
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Using froth flotation to mitigate acid rock drainage risks while recovering valuable coal from ultrafine colliery wastes
This dissertation presents the results of an investigation to develop a two-stage flotation process to produce: (i) a low-volume sulfide-rich concentrate that can be treated chemically or biologically or disposed of in a contained manner; (ii) a high-volume (low sulfur) benign tailings, with low …
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Developing quantitative approaches to determine microbial colonisation and activity in mineral bioleaching and characterisation of acid rock drainage
Colonisation of mineral surfaces by acidophilic microorganisms during bioleaching is important for accelerating the extraction of valuable metals from mineral sulfide ores of varying grades through biohydrometallurgy. It also influences acid formation and mineral deportment from sulfidic waste rock …
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Application of mineralogy in the interpretation of laboratory scale acid rock drainage (ARD) prediction tests : a gold case study
… that when exposed to air and water react to form acid, which results in acid rock drainage (ARD). ARD is usually associated with low pH, high sulfate content and elevated concentrations of toxic elements. The mobility of ARD affects our scarce water resources, land and aquatic species. Methods …
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An economic analysis of coal desulpharisation by froth flotation to prevent acid rock drainage (ARD) and an economic review of capping covers and ARD treatment processes
Acidic drainage as a result of mining and mineral processing activities is a growing concern. The effects of Acid Rock Drainage (ARD) include environmental pollution in the affected areas and beyond. As South Africa has water challenges, the potential threat of continual depletion of useable water …
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HYDROLOGICAL CHARACTERIZATION OF A SULPHIDE WASTE ROCK DUMP
Acid rock drainage (ARD) from sulphide bearing waste rock dumps poses a serious threat to the environment and has become problematic to the mining industry. Water that is discharged from sulphide waste rock dumps has the potential to be low in pH, thus having the ability to transport heavy metals. …
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Effects of intermittent irrigation on the extraction of copper from heap bioleaching systems.
… microorganisms contribute to the formation of acid rock drainage (ARD) through the oxidation of base metal sulfides, particularly pyrite. In this research, the effect of intermittent irrigation on the extraction of copper and iron from a low grade chalcopyrite ore in the heap bioleaching system …
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An investigation towards passive treatment solutions for the oxidation of sulphide and subsequent removal of sulphur from acid mine water
… utilised to treat the voluminous quantities of acid rock drainage that are being generated within South Africa, largely as a result of groundwater rebound through abandoned workings. However these technologies are not economically viable for the treatment of smaller discharges from diffuse …
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Integrating Microbial Fuel Cells (MFCs) into the treatment of sulphate-rich wastewater
… of sulphate-rich wastewater, and in particular Acid Rock Drainage (ARD), has become of increasing importance in water sparse countries like South Africa where mining is currently and has taken place. A semi-passive method of continuous ARD waste treatment is currently being investigated within …
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An investigation into accelerated leaching for the purpose of ARD mitigation
World-wide, acid rock drainage (ARD) is one of the biggest environmental challenges facing environments with current or previously active mining activities. Formed from the exposure of sulphide mineral to both water and air, and catalyzed by naturally occurring iron- and sulphur-oxidizing …
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Combining froth flotation and reflux classification to mitigate ARD generating potential of the Waterberg and Witbank coal ultrafines via sulfide removal
… to adverse environmental effects such as acid rock drainage (ARD). The University of Cape Town (UCT) has developed a two-stage flotation process, which involves coal flotation in the first stage and pyrite flotation of the tailings in the second stage, for mitigating the ARD potential of …
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Evaluation of Sulfidic Materials in Virginia Highway Corridors
… materials in Virginia has resulted in localized acid rock drainage (ARD) that threatens water quality, fill stability, integrity of building materials, and vegetation management. The objectives of this study were: i) to develop a state-wide sulfide hazard rating map based on characterization of …
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Life cycle assessment of the production of xanthate salts and of their application for ARD mitigation
… and coal waste, with a view to mitigating acid rock drainage (ARD) risks through the pre-disposal removal of sulphide minerals. In South Africa, xanthate salts are produced by Senmin® International (Pty Ltd) via the conversion of carbon disulphide at its facility in Sasolburg. In 2010, …
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Acid biodesulphurisation of coal discards using a heap leaching approach
… amount of wastes, which include waste rock, coal discards, and coal fines, posing significant environmental risks. The presence of sulphidic minerals, particularly pyrite, in these wastes can lead to the formation of acidic runoffs, known as acid rock drainage (ARD), when exposed to …
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Desulphurisation of fine coal waste tailings using algal lipids
… in the waste have resulted in the generation of acid rock drainage (ARD). A lot of techniques have been developed to prevent and mitigate ARD, however most of these techniques have fallen short in terms of meeting their desired objectives due to the long-term nature of ARD generation which can …
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Desulphurisation flotation for the selective removal of pyrite from coal discards using microorganisms
… and coal mining produce large amounts of waste rock and coal discards that contain significant quantities of sulphide minerals with Acid Rock Drainage (ARD) generating potential. ARD is caused by the exposure of sulphide minerals, primarily pyrite (FeS2), to both water and oxygen, and …
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Towards the development of an integrated modelling framework underpinned by mineralogy
… potential of the final tailings to generate acid rock drainage (ARD). The ARD method used is based on the relative abundance of acid generating sulfide minerals (chalcopyrite, galena, sphalerite and pyrrhotite) and other minerals with the theoretical potential to neutralise the acid …
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Characterizing the potential environmental risks of South African coal processing wastes
… pollution and soil quality degradation due to acid rock drainage (ARD) and its associated elevated levels of elements and salts. Several studies have shown the environmental performance of the wastes to be dependent on the geochemical properties of the wastes. Owing to the complex nature of …
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