Understanding how time-dependent changes in biogeochemistry, microbiology and mineralogy of mine waste can contribute to, or limit the impact of, environmental metal pollution – PhD (Funded)

The University of Exeter’s College of Engineering, Mathematics and Physical Sciences is inviting applications for a fully-funded PhD studentship to commence in September 2019 or as soon as possible thereafter. For eligible students the studentship will cover UK/EU tuition fees plus an annual tax-free stipend of at least £15,009 for 3.5 years full-time, or pro rata for part-time study. Students who pay international tuition fees are eligible to apply, but should note that the award will only provide payment for part of the international tuition fee and no stipend. The student will be based in Environment & Sustainability Institute and Camborne School of Mines, in the College of Engineering, Mathematics and Physical Sciences at the Penryn Campus in Cornwall.

Project Description:
Freshly processed metal mine waste is geochemically unstable and over time will react with the atmosphere, which can generate acidity and liberate metals in the form of acid mine drainage, or alternatively mineral surfaces can passivate or secondary minerals can form, preventing further metal mobilisation. These processes will vary on a case by case basis, with microbial activity playing a crucial role in catalysing these mineral reactions. Not only this, a functioning microbial community is essential for mine wastes to become revegetated, which prevents erosion and consequently limits the impact of metal pollution on the wider environment.

This project will characterise the biogeochemistry, microbiology and mineralogy of freshly processed and aged mine wastes from Wheal Jane, Cornwall. It will look for evidence for biogeochemical cycling of metals within the wastes, and for ageing of the amorphous waste into secondary, more crystalline forms, both over time and with depth. The microbial community will be characterised, and patterns in the time it takes for waste to be colonised by a functional, essential element cycling community will be sought. Laboratory experiments will simulate ageing processes to understand the mechanisms of metal incorporation into new minerals.

The Wheal Jane site offers an unparalleled opportunity to study the time dependence of mineral ageing and microbial community dynamics as there is a unique record of when the waste was deposited. The findings from this research could be used to design strategies to enhance beneficial microbial processes and encourage the formation of recalcitrant secondary mineral phases. This is not only applicable to the Wheal Jane site, it could also help to address the issues of how mine waste is disposed of globally.