Hydrochemistry characteristics and connection of aquifers in deep karst mine

In recent years, mine water inrush accidents occurred several times in North China type coalfield during the mining process of the upper group of coal, and possessed great threat. Taking Dongtan Coal Mine as an example, statistical analysis, Piper trilinear diagram, Gibbs diagram, Chlorine-alkali index were used to analyze the hydrochemistry of the surface water and aquifers. The results show that the surface and groundwater in the research area is generally alkaline, rock weathering process is the main factor influencing the water quality, secondly is evaporation and precipitation, the atmospheric precipitation has little impact. The ion sources of aquifers are mainly silicate, evaporite and carbonate weathering and cation exchange. It is inferred that the hydraulic connection among Ordovician aquifer, surface water, Quaternary and the 14th limestone aquifers is close, Jurassic sandstone aquifer and No.3 coal roof sandstone aquifer have certain hydraulic connection. It is predicted that in the future, the fi