Solute Geochemistry and Multivariate Analysis of Water Quality in the Guohua Phosphorite Mine, Guizhou Province, China

Water plays a critical role in securing the mine production and domestic consumption in mining areas. This research was carried out to assess the water quality status and to identify the hydrochemical processes contributing to the dissolved constituents of the water in the Guohua phosphorite mine, Guizhou Province, China. Multivariate statistical techniques and correlation analysis were employed to gain a better understanding of the hydrogeochemical processes, and water quality for domestic and irrigation purposes was also assessed. The results indicate that groundwater and surface water quality in the phosphorite mine area is currently excellent with low concentrations of major ions, salinity, and trace metals. Whereas, E. coli is excessive in groundwater and surface water, and treatment is required before the water is used for drinking purpose. Groundwater and surface water are, however, suitable for agricultural purposes. The major ions are Ca2+, Mg2+, and HCO3-, and all water samples are predominantly of the HCO3-CaMg type. Hierarchical cluster analysis (HCA) indicates that the water chemistry in the mining area is regulated by natural processes that are controlled by the different geological formations and different hydrogeological settings. Carbonate dissolution/precipitation is the key factor controlling the concentrations of Ca2+, Mg2+, and HCO3-. Pyrite oxidation is an important factor influencing the concentration of SO42-, whereas evaporation is a minor factor regulating the water chemistry in the mining area. The study results are beneficial for sustainable water quality management in the mining area, and they will also interest mine hydrogeologists and practitioners of the world as a reference for relevant studies in other regions.