Best Practice Guidelines for Prevention and Control of Spontaneous Combustion

Dolerites in the study area differ in mineral content, geometry, thickness, grain size and degree of alteration. Plagioclase textures indicate fractionation at different depths in the crust for the Witbank and Sasolburg intrusions, and the olivine content points to separate magma sources for two of the sills. Fine crystalline dolerite, including chilled margins and bifurcations, alters most readily.

Ion exchange converted reverse osmosis brine from a power station treating colliery water and cooling tower blowdown into fertiliser and explosives salts, with no liquid effluent left to dispose of. Part of the water rejected by the reverse osmosis stage was also recovered as potable water. Brine is currently used for dust suppression and stored underground.

Hydrogen for biological sulphate removal can be generated on site by electrolysis more cheaply than it can be bought. Stainless steel electrodes in acid mine drainage gave hydrogen at about a third of the bought in price while oxidising ferrous iron to ferric, which helps downstream treatment. Iron and zinc electrodes dissolved too quickly to be viable.