Hydrogeochemical genesis and irrigation suitability evaluation of mine water in Yiqiao Coal Mine

In order to understand the hydrogeochemical characteristics, formation mechanism and water quality suitability of mine water in Wenshang Yiqiao Coal Mine Co., Ltd. (hereinafter referred to as "Yiqiao Coal Mine"), a total of 138 water samples of sandstone mine water (SMW), limestone mine water (LMW) and mixed mine water (MMW) were selected, and statistical analysis, hydrogeochemical methods, sodium adsorption ratio (SAR) and sodium content percentage (ω(Na)/%) were comprehensively used for related research. The results show that the mine water in Yiqiao Coal Mine is weakly alkaline as a whole. The main cations and anions in mine water are Na⁺ and HCO₃⁻, respectively. The average concentration of cations in SMW, LMW and MMW has the relationship of Na⁺＞Ca²⁺＞Mg²⁺＞K⁺, and the average concentration of anions follows the order of HCO₃⁻＞SO₄²⁻＞Cl⁻＞NO₃⁻. The hydrochemical types of mine water are mainly divided into HCO₃-Na type and SO₄•Cl-Na type. The hydrogeochemical characteristics of mine water are mainly controlled by rock weathering and evaporation crystallization, but cation exchange is also an important hydrogeological chemical process that affects the chemical characteristics of mine water, and is dominated by positive exchange.