Socio Economic Aspects of Mine Closure

Market prices are set out for sodium sulphate, sodium chloride, sodium nitrate, potassium nitrate and potassium chloride, in South Africa and abroad, as at early 2011, with Chinese supplier quotes alongside United States averages. The work was done to test whether salts recovered from mine water brine could be sold at a worthwhile price.

Run of mine and discard coal carried total rare earth contents of 260 and 265 ppm, above the 130 ppm cut off grade used for coal. Flotation with an emulsion binder did not raise those concentrations in either the product or the tailings streams. Calcination did, lifting totals to between 285 and 289 ppm, with most rare earths leaching within the first fifteen minutes.

Compaction on rehabilitated opencast land restricts effective rooting depth so severely that only a small proportion of arable and grazing areas reach their stated capability. The review sets out the causes and symptoms, argues that symptoms are usually treated without addressing the cause, and recommends site specific, resource based management, mechanisation choices weighed against compaction, and land capability standards aligned with international codes.