Project Title:Sulfur and oxygen isotope implications for the sulfur-related geochemical processes at a South African colliery
Research Theme: Licence to Operate
PI/Supervisor(s): Megan Becker, Jennifer L. Broadhurst, Sue Harrison Juarez Amaral Filho and Jochen Petersen
Coal mining produces large quantities of waste that have the potential to release contaminants into the environment. This case study is focused on a coal mine in Mpumalanga Province, South Africa. The colliery produces coal for export and domestic markets using the continuous mining method followed by coal crushing and washing. The coal discard dump acts as an integrated residue facility, where both discard and slurry are stored. Only one of the pollution control dams is plastic-lined which raises the risk of the contamination of groundwater resources. Surface and groundwater qualities in the operation area highlight the impact of coal mining activities as acidic and neutral pH, along with high sulfate, iron and magnesium concentrations are detected. The supposed source of magnesium is the saline pore water of the underlining sediments. Based on this assumption, the first aim of the project is to assess the source of sulfur (gypsum versus pyrite), secondly to track sulfur conversions across the mine by sampling water at different stages of its surface cycle. The expected findings of the project can ultimately be used to inform the improvement of geotechnical designs of storage facilities, water management plan or water quality monitoring program.