Rehabilitation risk assessment model

Watercourses on post mined land near Kriel showed deterioration in manganese, calcium, magnesium, sodium, total dissolved salts and sulphate, while other parameters stayed within drinking water standards. Aquatic invertebrate communities had suffered significant losses and two sites were classified as eutrophic. The water is not fit for human consumption or recreation, and a minimum 32 m buffer from wetland boundaries is recommended after earthworks.

Dolerite intrusion mechanisms and their metamorphic effect on coal were examined across four collieries in the south eastern Witbank Coalfield. In decreasing order of importance, intrusions cut safety by raising the risk of roof, pillar and floor failure, raise mining costs, reduce saleable tonnage, and increase waste generation and environmental risk.