Statistical analysis of hydrochemistry of groundwater and its implications for water source identification: a case study

Hydrochemistry of groundwater is important for inrush water source identification in coal mines. For determining the source of inrush water from the 8101 working face in the Wolonghu coal mine, Northern Anhui Province, China, a total of 22 groundwater samples from three aquifer systems (loose layer—LA, coal bearing sandstone—CA, and the underlying limestone—TA), and eight samples from the 8101 working face were collected for analyzing major ion concentrations. The results suggest that major ion concentrations of the aquifer systems were different from each other, and they can be subdivided into Na–HCO₃, Na–SO₄, and Ca–SO₄ types. Factor analysis indicates that their chemical compositions are mainly originated from two kinds of contributions: dissolution of soluble minerals (e.g., calcite, dolomite, and gypsum) and weathering of silicate minerals (e.g., plagioclase). Plots of factor scores and cluster analysis imply that LA was connected with CA, whereas TA was an isolated aquifer system. Moreover, the source of 8101 working face water was finally determined to be LA by using discriminant analysis.