Frictional Ignitions Potentials Map for South African Coal Mines

Irrigation with calcium and sulphate rich mine water proved feasible and sustainable over eight years at a Mpumalanga colliery, with no significant impact on soil, surface water or groundwater. Sugarbeans, wheat, maize, potatoes and pastures were grown on a commercial scale. High calcium and magnesium suppressed potassium uptake, and waterlogging from poor site selection was the main problem.

Sub-seams within the No 2 Seam were characterised at a single test site using lithology, seam thickness, proximate analysis, petrography and geophysical logs, and a paleoenvironmental model was built from them. Wireline logs separated coal from interburden but could not resolve the individual zones, because the physical differences are too subtle. Better sedimentological models gave better reserve and resource estimates.