Hydrogeochemical characteristics and evolution mechanism of groundwater in the Guqiao Coal Mine, Huainan Coalfield, China

To study the influence of coal mining on the hydrogeochemical process of groundwater, taking Guqiao Coal Mine, Huainan coalfield as an example, 32 groundwater and 4 surface water samples, 4 mine drainage samples and atmospheric precipitation were collected in the mine, and the hydrochemical type, TDS, and TH were analyzed using Piper diagram, principal component analysis, and chemical analysis of water samples. The relationship between Cenozoic and Permian aquifers was discussed and the potential mineral phases in groundwater were determined by Phreeqc software. The results show that hydrogeochemical processes of aquifers in the study area are mainly the dissolution of halite and cation exchange and desulfurization of in the Permian sandstone fracture. Inverse modeling was used to verify hydrogeochemical responses in diverse paths. Consequently, shallow groundwater and surface water are connected, and the two main kinds of water have relatively independent hydrogeochemistry. This suggests that the sealing properties of the hydrogeological in the coal field are good. These data analysis methods and results could be useful for the interpretation of groundwater evolution and the management of groundwater disaster in areas of long-term mining.