Characteristics and the origins of the main chemical components in mine water in the Xishan mining area, North China

摘要

Analyzing the characteristics of the chemical composition of coal mine water and discussing its formation process can provide baseline information for the prevention and control of water hazards. In this study, 152 mine water samples from 8 coal mines in the Xishan mining area (XSMA) were sampled, and their chemical characteristics and formation mechanism were analyzed comprehensively using standard hydrochemical and statistical methods. The results show that the main cations in the mine water are Na+ and Ca2+, and the dominant anions are SO42- and HCO3-. The mine water of Xiqu coal mine showed the highest concentrations of Ca2+, Mg2+, and SO42- ions, and the Guandi coal mine showed the highest Na+ content, but both mines showed relatively low Cl- concentration. Ca2+ and Mg2+ were significantly positively correlated with SO42-, while pH was significantly negatively correlated with Ca2+ and SO42-. The 152 samples were divided into 6 categories (G1-G6) through cluster analysis. Specifically, the hydrochemical type of G1 is HCO3-Na, G2 and G3 are mainly SO4 center dot Cl-Na, G4 is mainly HCO3-Ca center dot Mg, G5 is mainly SO4 center dot Cl-Ca center dot Mg type, and G6 is mainly SO4 center dot Cl-Ca center dot Mg and SO4 center dot Cl-Na. Through principal component analysis, three principal components were obtained, representing the oxidation of pyrite and the dissolution of carbonate and sulfate minerals, the weathering and alternating cation adsorption of silicate rocks, and the effects of rock salt dissolution and evaporative concentration. The ion proportion coefficient and principal component analysis showed that the mine water from the XSMA is mainly affected by rock (silicate and carbonate rock) weathering, mineral (gypsum) dissolution, cation exchange, and pyrite oxidation. The results are of great significance to the identification of mine water-inrush sources and the prevention and control of water disasters in the XSMA.