Economic Geology and Mineral Geochemistry
The geochemical cycle of gold in earth’s crust
Gold remains a highly sought-after commodity and finds use as a stable financial investment, in jewellery, and increasingly, in electronics and medical fields. Broadly, the geochemical cycle of gold comprises hypogene ore-forming processes that operate within the earth’s crust (e.g., orogenic gold deposits that form at mid-crustal levels), and an active (bio-)geochemical cycle in the earth’s critical zone once these deposits have been uplifted to surface for subsequent weathering and erosion. This research thrust considers all aspects of the crustal gold cycle, with particular emphasis on orogenic gold systems and gold ore deposits that have formed on the African continent. The research focus further includes consideration of how gold and its associated host mineralogy behave in the surficial environment, with emphasis on understanding deportment and transformations occurring in mine tailings dumps.
Ore deposits on the African continent
In comparison to many other parts of the world, the African continent is relatively under-explored and its known ore deposits have generally received less scientific attention than deposits hosted in other more-developed parts of the world. As a result, there remains vast potential for new and exciting research to derive from these deposits. The Economic Geology research unit has addressed and continues to address a vast array of different commodities hosted in often far-flung regions of Africa. Commodities that have been studied include copper and cobalt mineralisation in the Democratic Republic of Congo (DRC); lead and zinc endowments hosted in Broken-hill type deposits of the Northern Cape (RSA); kimberlite and placer diamonds respectively hosted in Botswana and Namibia; Lithium-Caesium-Tantalum class pegmatites (Northern Cape, RSA); and a variety of gold occurrences in South Africa, Zimbabwe, Tanzania, Malawi and the DRC. Many of the hydrothermal classes of ore deposits have benefitted from studies that utilised the brand-new fluid inclusion micro-thermometry laboratory hosted at Stellenbosch University. Finally, several B.Sc. Honours level projects focussed on coal have also been completed successfully.
As far as possible, the Economic Geology unit would like to facilitate and encourage interactions with industry partners, particularly in instances where dedicated scholastic research will help to solve questions or daily issues experienced in a mining geology environment.
For more information, either from prospective students or from potential industry partners, please contact: Dr von der Heyden, bvon at sun.ac.za
Applied and theoretical geometallurgy
The SU Economic Geology research hub boasts an excellent working relationship with the SU Department of Process Engineering. Multi- and inter-disciplinary research holds many advantages of traditional ‘ivory tower’ type research endeavours and the match between geology (mineralogy) and minerals engineering is one which is particularly well suited for successful research. Geometallurgy type studies that have been completed or which have been successfully completed include micro-analytical studies of the effects of trace elements on mineral flotation response, and dedicated investigations into the deportment of gold in mine tailings facilities.
contact: Dr von der Heyden, send e-mail
Application of synchrotron radiation and other spectroscopic tools to the 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. In addition, other high-level spectroscopies (e.g., UV-Vis; Raman and Fourier Transform Infrared (FTIR) spectroscopies) are commonly utilised to help answer ore geology related questions. Studies will focus primarily on ore geology; yet other geological, geochemical and biogeochemical questions may also be investigated.
Contact: Dr von der Heyden, send e-mail