Geotechnical Factors Affecting High- and Low-wall Stability in Opencast Coal Mine

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.

The fine coal dense medium pilot plant was rebuilt at South Witbank Coal Mine and run on fine coal, with tests covering single, double and three stage processing, the effect of recirculating load, magnetite size and losses, separation efficiency and continuous operation. The fast screen could not deliver the required capacity and was replaced by dewatering cyclones to deslime the feed.