Change of regional water chemistry driven by group coal mining in Changzhi basin, Shanxi, China

Abstract

Coal mining can deplete groundwater resources and discharge polluted water into the surrounding water bodies, decreasing the quality of ground and surface water. Group coal mining can drastically deteriorate regional water quality due to the overlying effects of multiple mines. As a country, China produces the most coal per year in the world. Group coal mining in China has caused a decline in the quality of many watersheds. This study introduced the regional water quality in Changchi basin, Shanxi province, which contains coal seams covering over 60% of its area and has over 10 active collieries. Coal mine discharge caused the increase of TDS, especially NO₃^-, in the river receiving the mining discharge. Quality of groundwater was also affected by the contaminated surface water when it was recharged by surface water. Reuse and treatment of mining discharged should be promoted in the area with high intensity of group coal mining.