The Northern Limb of the Bushveld Complex, South Africa is host to the world’s largest resource of platinum-group elements (PGE), along with significant nickel, copper and cobalt in a complex magmatic sulfide ore deposit. All of these resources are linked with environmentally-friendly technologies and energy usages in the automotive industry, with the PGE being essential components in catalytic converters, and Ni, Co and Cu critical metals in Electric Vehicle batteries. As such, the northern limb of the Bushveld is likely going to play a large part in the switch to cleaner automotive technology.
The major deposit in the Critical Zone of the northern Bushveld (commonly known as the ‘Platreef’) rests directly on variable basement of Archaean and Paleoproterozoic units at surface. Down dip, it overlies Bushveld Complex Lower Zone rocks; themselves prospective for base metal sulfide mineralisation. The stratigraphy, structure, mineralization styles and metal budgets of the Northern Limb of the Bushveld Complex show important differences to the other limbs of the complex. The underlying causes behind these differences are poorly understood and no geological model exists to investigate them on anything more than a local scale.
This PhD project aims to tackle questions surrounding the controls on the metal distribution through the Critical Zone; processes that occur after emplacement during cooling and crystallisation but are fundamental in determining the metallurgical characteristics of the ores. The project is in partnership with Anglo American, who have been mining the Platreef via surface methods since the 1990s, and now operate the world’s largest PGE surface mining operation at the Mogalakwena Mine. Whilst the near-surface resources are reasonably well characterised, the down dip potential and extension of resources is known, but has had no research work completed on it thus far. Therefore, this PhD provides the opportunity to work on one of the world’s greatest ore deposits, with resources critical for a greener future, and at a time when exploration and mining activities in the area are expanding.
1. Can Critical Zone mineralisation (in terms of metal tenors, ratios and host lithologies) be correlated from the shallow, Platreef resources into the deeper Platreef, and does it extend into predictable stratigraphic units of the Critical Zone?
2. Why are some zones more PGE-rich and others more base metal-rich?
3. How does fluid interaction affect metal ratios and sulphide tenors? How does alteration affect the metallurgical characteristics of the ores?
4. How do the metallurgical characteristics affect the amenability to processing using conventional and novel approaches?
In order to tackle the research questions, a multi-disciplinary approach will be used whereby the PhD researcher will undertake fieldwork in South Africa and make use of an unrivalled collective resource of laboratory facilities at Leicester, Cardiff and CSM (Exeter).
A. Fieldwork in South Africa to sample extensive drill core of the shallow and deeper stratigraphy of the northern Bushveld Complex. This will include basement, Lower Zone, Lower and Upper Critical Zone, and the base of the Main Zone units. Sampling from drillcore will form the basis of lab work to tackle questions 1-4 (see B-E).
B. Detailed and careful stratigraphic correlations in terms of mineralogy (including the use of hyperspectral data) and chalcophile metal geochemistry between boreholes to address questions 1 and 2.
C. Textural and quantitative mineralogy; platinum-group mineral studies; bulk chalcophile geochemical characteristics; to address question 3. Automated mineralogy will also determine metal deportment and grain association – thus giving early insight on processing amenability relevant to question 4.
D. In situ leaching experiments of PGE-bearing minerals and base metal sulfides using novel deep eutectic solvent processing to address question 4.
Applicants are required to hold/or expect to obtain a UK Bachelor Degree 2:1 or better in a relevant subject or overseas equivalent.
Experience of economic geology, igneous petrology and/or structural geology would be a benefit.
The University of Leicester English language requirements apply where applicable. https://le.ac.uk/study/research-degrees/entry-reqs/eng-lang-reqs/ielts-60
Project / Funding Enquiries: [email protected]
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Application enquiries to [email protected]
How to apply
Please refer to https://le.ac.uk/study/research-degrees/funded-opportunities/geol-sgge-holwell-2
Grobler, DF, Brits, JAN, Maier, WD and Crossingham, A., 2018, Litho- and chemostratigraphy of the Flatreef PGE deposit, northern Bushveld Complex. Mineralium Deposita 54, 3-28.
Holwell DA, Adeyemi Z. Ward LA, Smith DJ, Graham SD, McDonald I, Smith JW. 2017. Low temperature alteration of magmatic Ni-Cu-PGE sulfides as a source for hydrothermal Ni and PGE ores: a quantitative approach using automated mineralogy. Ore Geology Reviews, 91, 718-740