The project will study Coal Measures stable isotopic landscapes and stratification at two scales:
(a) National: via Coal Authority-managed mine water discharges, pumping stations and treatment sites. (The Coal Authority manages around 75 treatment schemes in the UK – https://www2.groundstability.com/services/treating-mine-water/).
(b) Local: via study of the Blast Beach, Dawdon, Co. Durham anthropogenic coastal landscape. The beach contains colliery spoil containing pyrite; secondary sulphate minerals (tentatively identified as jarosite, alunite and sulphur), acidic sulphate lagoons, marine sulphate aerosols, marine water. Adjacent to the beach is the deep saline Dawdon colliery minewater environment, currently pumped and under consideration for use as a geothermal heat source.
The PhD student will link with the Coal Authority (CA) and develop a plan to visit (under supervision, where necessary) as many of the CA’s large minewater discharge sites, which comprise shallow gravity drainages, pumped deep collieries and intermediate overflows from adits, as practically feasible (with a target of 30-40), throughout England, Scotland and Wales. At each site, field parameters such as pH, electrical conductivity, alkalinity, temperature and redox potential will be measured, and samples of mine water will be collected. These will be analysed for:
1. Dissolved sulphate δ34S and δ18O at the NERC-funded SUERC / University of Glasgow isotope laboratory.
2. Water δ18O and δ2H also at SUERC.
3. Where the CA do not already routinely sample and analyse for hydrochemistry, major ion chemistry and selected minor ions (tentatively to include Ba, Sr, Br, Li, Fe and Mn) will be analysed at the hydrochemical engineering laboratory at the University of Newcastle.
The PhD student will also request access to the CA’s database of hydrochemical analyses of mine water to extend the data set, and will request access to the CA’s cores in order to compile a set of Coal Measures pyrite samples, analysed at SUERC to improve the UK data set on δ34S in Coal Measures pyrite (which is, at present, surprisingly sparse).
Selected coal mine waters with elevated δ34S values will be additionally sampled for analysis using metatranscriptomic techniques (c/o J Moreau) to examine whether expression of microbial sulphate reduction genes is occurring and, if so, which genes (bacteria, archaea). If a candidate with an appropriate microbiological background can be identified, rates of sulphate reduction using radioactive δ 35S labelling techniques can be investigated, contingent upon additional sources of funding being successfully sought within the University of Glasgow.
The PhD student will also visit Blast Beach, Dawdon. The beach has already been preliminarily characterised as part of the University of Newcastle’s (UoN) research programme (NERC Legacy Wastes in the Coastal Zone – https://research.ncl.ac.uk/legacywastes/). The student will systematically collect samples from all “compartments” of the beach’s sulphur isotope landscape: i.e. sedimentary pyrite in colliery spoil; secondary sulphate minerals, sea water, dissolved sulphate from acid lagoons, Dawdon deep mine water. Mineralogy will be characterised by X-Ray Diffraction (XRD) and the mineral sulphur content’s δ34S (and sulphate δ18O) will be characterised at SUERC.