Prof Gawen Jenkin (email@example.com), Dr Dan Smith (firstname.lastname@example.org), Andy Abbott (email@example.com),
Helena Moosberg-Bustnes (Mandalay Resources), Prof Karen Hudson-Edwards (Camborne School of Mines, University of Exeter)
Ore deposits represent geochemical anomalies where certain metals are concentrated by geological processes to the extent that some become economically exploitable. The product metals that are targeted for extraction, such as gold, are often accompanied by an array of other metals that are increasingly of interest for environmental technologies, yet these are often discarded or only partially recovered. For a sustainable future it is important that, where it is necessary to exploit primary mineral resources, this is done in a resource efficient manner with the lowest environmental footprint. This involves maximising the recovery of a much wider range of metals through optimising ore beneficiation and applying novel processing technologies. This PhD will develop this approach at a Swedish gold mine.
Mandalay Resources Corp is a Canadian-based metals miner listed on the Toronto Stock Exchange, producing gold, silver, and antimony from operating mines in Sweden (Björkdal) and Australia (Costerfield). Mandalay’s Björkdal mine produces gold with minor silver. However, the mineralisation and the mineral concentrates produced, contain potential by-product technology metals, specifically tellurium, bismuth and tungsten. This project aims to develop environmentally-friendly and efficient processes for recovering these by-products to maximise use of the resource and decrease the overall environmental footprint.
Previous work with the University of Leicester recognised that the bismuth tellurides present in Bjorkdal concentrates would be amenable to processing with novel environmentally-benign Deep Eutectic Solvents (DES) along with the gold-silver product (Jenkin et al. 2016); tungsten could be left in a residue that may be a saleable tungsten concentrate. Developing this process will involve bench-scale tests to understand leaching of Björkdal materials for target elements and how these could be recovered from solution. Furthermore, because the mine receives no revenue for these potential by-products, the beneficiation circuits are not designed to optimise recovery of them. A key part of the PhD will therefore be to understand the flows of by-products through the processing plant and to provide a roadmap to optimise capture of these by-products into existing or new concentrates. Finally, in collaboration with researchers at University of Exeter Camborne School of Mines, the student will carry out an impact analysis of any proposed changes to apply circular economy principles to look at not only cost/benefit analysis but incorporate the environmental and socio-economic impact of proposed alternatives compared to the current processing model. By the end of the PhD Mandalay will have all the information required to decide whether commercial implementation of this new technology is possible.
Through this PhD you will receive training and develop skills in: Automated SEM analysis for mineralogical characterisation of ores, concentrates and tailings, leach testing using Deep Eutectic Solvents, impact analysis. This will equip you for a career in the minerals processing industry and allied areas, or academia.
This project forms part of the UKRI Technology Metals Circular Economy Centre (TechMet) a major initiative to bring together for the first time world-leading researchers to maximise opportunities around the provision of techmetals from primary and secondary sources, and lead materials stewardship, creating a National Techmetals Circular Economy Roadmap to accelerate the UK towards a circular economy. The consortium brings together the Universities of Exeter, Birmingham, Leicester, Manchester and the British Geological Survey who are already working on how to improve the raw materials cycle, manufacture goods to be re-used and recycled, recycle complex goods such as batteries and use and re-use equipment for as long as possible before it needs recycling. Through TechMet you will be networked with researchers across these institutions, including geologists, metallurgists, industrial chemists, social and economic scientists. You will work closely with a Post-doctoral Research Associate at Leicester who will be working in mineral processing in TechMet and a large team of researchers in allied areas in the Centre for Sustainable Resource Extraction.
Jenkin GRT, Al-Bassam AZM, Harris RC, Abbott AP, Smith DJ, Holwell DA, Chapman RJ, Stanley CJ (2015). The application of deep eutectic solvent ionic liquids for environmentally-friendly dissolution and recovery of precious metals. Minerals Engineering, 87, 18-24.
Jenkin GRT, Graham H, Smith DJ, Khan R, Abbott AP, Harris RC, Holwell DA, Graham SD, Stanley CJ (2019). Gold and critical element recovery with environmentally-benign Deep Eutectic Solvents. Proceedings of the 15th SGA Biennial Meeting, 27-30 August 2019, Glasgow, Scotland, pages 1512-1515.