Project Title: Quantifying texture for acid rock drainage (ARD) characterisation
Supervisors: Megan Becker (primary supervisor); Jennifer Broadhurst (co-supervisor); Susan Harrison (co-supervisor)
Minerals, metals and mining are essential for the support of modern-day life and technological development. Mining, however, is not a waste-free process and results in a host of environmental problems, including acid rock drainage (ARD). ARD forms through a complex series of acid formation, neutralisation and mineral dissolution reactions, with resulting drainage waters often being acidic, highly saline and having elevated levels of deleterious elements. Effective ARD mitigation strategies require knowledge of the ARD formation potential of the waste material. Currently, ARD assessment predominantly comprises a suite of geochemical static (characterisation) and kinetic (prediction) tests, with the former providing a quick estimate of the “worst case” scenario for ARD formation and the latter aiming to predict the long-term weathering potential of the waste material. Although effective in some cases, this ARD assessment strategy does require adjustments, as it does not consider the roles of mineralogy and texture in ARD formation, which have been identified as additional factors governing ARD formation.
Mineral texture describes the interrelationship of mineral grains with one another, their shapes and sizes. Some commonly studied textural parameters include mineral liberation, association, grain size distribution and particle size. These have been shown to influence metal recovery in (bio)leach heaps, which have similar reaction mechanisms to those of waste rock dumps. A poor understanding of the role of texture in ARD formation can ultimately lead to significant techno-economic, environmental and social consequences.
The overarching objective of this project is to determine the dominating textural parameters (specifically mineral association and liberation) influencing characterisation and prediction test results. This study aims to build knowledge on the role of texture in the ARD assessment “toolbox” as an additional parameter for laboratory ARD test result interpretation by reconciling the results of quantitative textural and mineralogical analyses with results of characterisation and prediction tests.
Guseva, O., Opitz, A.K.B.., Broadhurst, J.L.., Harrison, S.T.L.., Bradshaw, D.J.. & Becker, M. 2018. Fe-Sulfide Liberation and Association as a Proxy for the Interpretation of Acid Rock Drainage (ARD) Test Results. In 11th International MineWater Association/International Conference for Acid Rock Drainage (11th ICARD | IMWA |MWD2018). Mine Water – Risk to Opportunity (Vol I). C. Wolkersdorfer, L. Sartz, A. Weber, J. Burgess, & G. Tremblay, Eds. Pretoria. 345–351.