Evaluation of New and Emerging Mine Water Treatment Technologies

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.

Aircraft and ground based measurements at Kleinkopje Colliery showed spontaneous combustion to be a significant source of fine particles, with PM2.5 concentrations 91 per cent higher inside a combustion plume than outside it. Sulphur dioxide, nitrogen dioxide and carbon dioxide were also raised in plume, and benzene and toluene were detected. Average particle size was below one micron.

A compound dry cleaning machine de-stoned low grade raw coal without using water, but separation efficiency was low, with high relative density cut points and EPM values in the order of 0.3. Misplaced material was heavy and coal below 6 mm reported to product almost indiscriminately. The unit is cheap to buy and run, needs only crushing to 50 mm, and gives high throughput.