Sinkholes in karst mining areas in China and some methods of prevention

Mining of coal, lead and zinc, gold, and iron ore deposits in karst areas h as been closely associated with sinkholes in China. Surface collapse causes an increase in mine water drainage and the possibility of major water infl ow from karst aquifers, which threatens the environment in mining areas and endangers the mine safety. A combination of factors including soil weight, buoyancy, suffusion process and vacuum suction can contribute to the sinkh ole formation. The key measures to prevent sinkholes in mining areas are to control the amount of mine drainage, reduce water level fluctuation, seal- off karst conduits and subsurface cavities in the overlying soil, prevent w ater inflow, and/or to increase gas pressure in the karst conduits. (C) 199 9 Elsevier Science B.V. All rights reserved.