Vermicomposting of Industrial Organic Wastes and its Application in Mine Rehabilitation Strategies – An Overview from a South African Perspective

Large areas of land are needed to dispose of wastes produced by mining activities worldwide which poses a myriad of environmental hazards with regards to soil, water and air contamination. This is a problem, especially for a mining country like South Africa, where more than 1500 mines are registered which affects 0.2 million ha of land. Legislation in this country do, however, stipulate that disturbed land should be rehabilitated/revegetated but this is both difficult and expensive because of the unavailability of potential topsoil as well as deficiencies in organic matter, elemental imbalances, and absence of essential nutrients. The use of waste and residual organic matter in soil amendment strategies has been well documented with vermicomposting as a prime example of this. Waste woodchips produced by the platinum mining industry in South Africa have been identified as an organic ameliorant during the rehabilitation of platinum tailings. Based on this, several mines in South Africa, including diamond, iron and platinum, were identified where remediation had to be done on tailings dams. This paper gives an overview of the vermicomposting study undertaken and how successful the use of this product was in real world conditions on different rehabilitation strategies from a South African perspective. The presented studies aim to ascertain the feasibility of utilising vermicomposting of industrial organic wastes and its application in mine rehabilitation strategies under South African conditions. Specific objectives included the evaluating the efficiency of utilising vermicompost on platinum, diamond and iron ore tailings dams by determining rehabilitation success. The results presented in this review are based on these studies; some of which have been published already. _____________________________________________________________________________________________________________