Post-mining rehabilitation, land use and pollution at collieries in South Africa

Coal mining in South Africa is a mature industry and there are large numbers of closed collieries in the country’s major coal fields. The state in which these collieries have been left varies greatly from best practice closure to abandonment, with most collieries in the latter category having closed some time ago. Today, the large multinational mining companies that dominate South Africa’s coal sector apply scientific methods in surface rehabilitation and take steps to mitigate future pollution from closed mine sites. The socio-economic impacts of closing collieries are also recognised and companies participate in local economic development initiatives and integrated planning frameworks to reduce the dependency of local communities on mines before closure. The challenges faced in closing coal mines should not be underestimated. The reactive nature of coal and its associated strata and the high level of surface disturbance result in potentially significant pollution problems which may persist for many years after mining has ceased. Methods exist to rehabilitate the surface and to ameliorate pollution, but the long-term success of these interventions depends on the nature of post mining land uses. There are instances where coal seams have been illegally re-accessed by artisanal miners after a mine has closed or where rehabilitated land has been inappropriately utilised by farmers. This may create water pollution, spontaneous combustion and severe safety and health hazards. In other cases, mines awaiting closure certification effectively sterilise surrounding coal measures as these cannot be accessed if such mining will potentially disturb the rehabilitated mine. This state may persist for years before a final closure certificate is issued. Successful closure must consider medium to long-term post-mining land use and, critically, land capability. This paper reports on experience at selected South African collieries and draws conclusions regarding future optimisation of post-closure land use.