Economic Geology and Mineral Geochemistry​

  • Energy commodities

The status of Southern African electricity supply remains critical and there is thus strategic incentive to more fully understand the geology, geochemistry and geometallurgy of the raw materials associated with the energy sector.

Coal

Historically, coal has been the dominant contributor to the Southern African power grid, and will continue to dominate in at least the next decade. However, the depletion of the high quality reserves and a global paradigm shift towards cleaner energy production, emphasise the need for geometallurgical understanding and treatment of lower grade coal. Examples include the spatial distribution and density separation of highly abrasive coal; depositional basin characteristics as a control on maceral distribution and coal quality; application of novel techniques to evaluate coal characteristics (X-ray computed tomography and computer modelling).

Uranium

The increased public awareness that coal fired power generation has a detrimental impact on global climate, coupled with the increased demand for electrical power has resulted in a renewed interest in nuclear energy generation. The Damara Belt in central Namibia hosts leucogranitic sheets and stockworks that are mineralised with uranium; however, the controls of the U mineralization, U precipitation and, in particular, the formation of higher grade ore lenses have not been fully constrained. Similarly, the actual U mineral phases are complex and only poorly known, complicating the beneficiation and metallurgical processes. Research in this area will focus on characterising ore textures and assemblages to discern between primary and secondary (remobilized) mineralization; investigate wall-rock alteration to determine the importance of wall-rock interactions as a chemical trap for U mineralization; and utilise high level geochemistry principals to understand the nature of the mineralising fluid.

 contact: Dr von der Heyden, bvon at sun.ac.za


  • Southern African ore deposits

Southern Africa hosts a diverse array of mineral deposits and the prospects for academic investigation is limitless. Bulk commodities, in particularly, have historically been under-studied and planned research interests will focus on banded iron formations (e.g., Sishen deposit) with particular emphasis on their mineralisation and the implications for the evolution of the earth's atmosphere and early biogeochemical systematics.

Furthermore, the supervision (in the capacity of an Economic Geology lecturer) of geology Honours students and their year-long Honours project renders exciting opportunities to investigate scientific aspects of various local ore deposits. This can be particularly beneficial when incumbent honours students conduct holiday work on local mines, or are affiliated to the industry through bursary obligations. Some arguments for this model, which will be tested in 2016, include:

  1. The students have the opportunity to prove their work ethic and standard of work to whichever company is able to offer them a project. The students are also impressing upon the respective companies their drive and initiative. These factors will stand the students in a better position to apply for jobs in the industry and, given the paucity of mining-related jobs in the current economic climate, every little advantage will help.

  2. Honour's projects typically cost between R15 000.00 – R30 000.00 depending on the nature of the work involved. This represents a relatively cheap investment for a year's worth of work, and, if the projects are designed correctly, can render valuable answers to the research/academic questions faced by the industry.

  3. These projects would enable that strong relationships can be developed between the industry and the academic institution. Such working relationships could foreseeably lead to exciting findings that are beneficial to the industry's needs whilst simultaneously making a significant contribution to broader scientific understanding.

 contact: Dr von der Heyden, bvon at sun.ac.za


  • Application of synchrotron radiation to geosciences

Synchrotron light sources are specialised particle accelerators that produce tuneable high intensity and high brightness X-ray radiation. The development of this technology has revolutionised scientific investigation, yet its application to the geosciences remains relatively under-developed. Examples of how synchrotron radiation has previously been applied to the field of Economic Geology include: non-destructive speciation studies of fluid inclusions in ore systems, trace-metal concentration and coordination in ore minerals, and the mechanisms involved in biological processing of ore minerals (e.g., gold beneficiation). The focus of this research thrust will be to apply existing synchrotron-based techniques, and to pioneer novel application of X-ray radiation. Studies will focus primarily on ore geology; yet other geological, geochemical and biogeochemical questions can also be investigated.

contact: Dr von der Heyden, bvon at sun.ac.za

 

  • Using X-Ray computed tomography for the 3D textural and mineralogical analysis of drill core in geometallurgy

As high grade ores become exhausted, mining activites are focussed increasingly on development of lower grade ores. However, this comes with additional processing challenges that require a detailed knowledge of the mineralogy, texture and variability thereof of these lower grade ores in real time. X-Ray computed tomography (XCT) provides the potential to deliver rapid mineralogical and textural information on ore characterisation to processing plants. With such possibilities, it is imperative that due diligence is taken to ensure that the inherent geometallurgical information embedded within the scanned XCT volumes can be extracted and manipulated to provide meaningful information that can be applied into designing and operating minerals beneficiation circuits. My work focusses on understanding the mineralogical and textural information from a geological perspective and integrating this with the requirements of the processing system. The work is conducted in collaboration with Dr Megan Becker from the Centre for Minerals Processing at the University of Cape Town. We are currently working on Ni-S, PGM and Iron ores.

contact: Dr Jodie Miller, jmiller at sun.ac.za