Research on the effects of coal mining on the karst hydrogeological environment in Jiaozuo mining area, China

Fissure karst water system in Jiaozuo coal mining area is one of the typical karst groundwater systems in north China. Based on the research of hydrogeological conditions and tests and monitoring data of karst groundwater systems in Jiaozuo mining area, this paper has carried out a discussion of the evolutionary trend of karst underground water and the origin and distribution rules of environmental geological problems caused by the exploitation. It is found that the mine drainage is the major way of underground water drainage in the mining area, and the actual drainage discharge is equivalent to 50% of the total natural groundwater recharge in Jiaozuo mine. With the increase of exploitation and decrease of precipitation, the karst water level in Jiaozuo mining area decreases in a ladder form and the cones of depression of the groundwater covering the entire mining area are developed rapidly. In addition, mine drainage brings a large number of pulverized coal and rock dust into the soil, causing soil pollution, reduction of the soil quality, and pollution of pore water by different degrees. Meanwhile, the pore groundwater has been also contaminated by mine drainage through irrigation backflow and channel leakage. On the basis of analysis above, some recommendations of prevention and protection measures for the karst water hydrogeological environmental problems in coal mining areas are provided.