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  'Working together to promote premier, multi-disciplinary research and development in the
                                                           area of minerals beneficiation'

Doctor of philosophy

Alex Opitz

 

 

PhD (commenced 2015)

Project Title: The Development of an Integrated Approach for the Prediction of Acid Rock Drainage from Waste Rock

Supervisors: Prof Sue Harrison; Assoc. Prof Jenny Broadhurst; Dr Megan Becker

Contact: optale001@myuct.ac.za

 

 

 

The formation of acid rock drainage (ARD) poses a serious environmental risk associated with the mining of sulphidic hard-rock ores and coal. Acidity generated from sulphide oxidation leads to an increase in heavy metals concentrations and salinity in the surrounding environment. ARD generation occurs naturally in the presence of water and oxygen and is catalysed by iron- and sulphur-oxidising microorganisms. Currently, the potential for ARD generation is characterised using a sequential process. Initially, chemical laboratory screening tests assess the overall potential for ARD generation. For samples which may produce ARD, kinetic tests are conducted to quantify the rate of acid generation using water and oxygen. The current methods, however, fail to account for the action of micro-organisms and to integrate the mineralogical composition of the waste with the ARD potential. This project aims to integrate the current ARD characterisation methods with detailed mineralogical analysis and test work developed to assess the role of micro-organisms on ARD generation. Furthermore, integration between laboratory-scale tests and those conducted in the field will be performed through the use of geochemical mass transport models.