Economic and Safe Extraction of Pillars and Associated Reserves Using Underground Mining Methods

Grazing trials on tall fescue pasture irrigated with gypsiferous mine water on rehabilitated mined land, run over several seasons. The work covers steer stocking rates, dry matter intake by cattle, and the factors that control pasture quality and intake, among them nitrogen fertilisation, stage of growth, sward structure and grazing intensity. Findings are reported study by study.

Sustainability in mining is still framed in neoclassical economic terms, measured by profit, shareholder value and growth, with social and environmental dimensions added in response to regulation. Six air quality and waste minimisation projects run over seven years were assessed against seven dimensions of the biosphere and fell well short. A collaborative model is proposed for a sector built on mining waste residues.

Four centrifugal concentrators all cut ash in fine coal, with desliming the decisive step. The best unit took ash from 35.2% to 18.47% and sulphur from 0.68% to 0.36% in a single stage, raising calorific value from 23.78 to 26.16 MJ/kg. Pilot work reached 19% ash on thickener underflow and reconstituted spiral feed.

Sets out good practice for planning, implementing, monitoring and adaptively managing land rehabilitation at surface coal mines, with generic rehabilitation objectives, implementation actions and suggested relinquishment criteria for each component. It updates guidance first issued in 1981 and revised in 2007, reflecting later changes to South African rehabilitation legislation.