Application of hydrochemistry for inrush water source identification in coal mine: approach based on statistical analysis

The source of chemical constituents in the groundwater and the source of inrush water are two important issues related to the hydrochemical evolution and safety of coal mining in coalfield of China, respectively. In this study, major ion concentrations of thirty-four groundwater samples from three representative aquifers in northern Anhui province, China have been analyzed by a series of statistical methods for tracing the sources of major ions and inrush water. The differences of major ion concentrations in groundwater from different aquifers indicate that they have undergone different types and degrees of water rock interactions, and provide the possibility for water source identification based on major ions. Factor analysis has identified two potential sources responsible for the major ion concentrations of the groundwater, including dissolution of carbonates and evaporates and the weathering of silicate minerals, which was further confirmed by the Unmix model analysis. Discriminant analysis can classify the sources of groundwater with high efficiency, similar to the results obtained based on the source contributions of the Unmix model analysis. In summary, different with those of factor and discriminant analysis, the Unmix model analysis can provide information about source of major ions and water simultaneously.