For the purpose of investigating the hydrochemical signatures and formation processes of mine water at the Feicheng Coal Mine, a total of 61 samples—including fresh mine water (FLW), old goaf water (OGW), and old lode water (OLW)—were collected and examined via statistical and hydrochemical approaches for the assessment of mine water suitability for irrigation employed sodium content (Na%), sodium adsorption ratio (SAR), permeability index (PI), and magnesium hazard ratio (MHR). The mine water proves slightly alkaline, featuring Na+ as the leading cation and SO42−/HCO3− as the leading anions. By average concentration, cations decrease in the order Na+ > Ca2+ > Mg2+, and anions decrease as SO42− > HCO3− > Cl−. The hydrochemical types of OLW and FLW samples were primarily Ca-HCO3 and Ca-Mg-Cl, whereas the OGW samples were predominantly of the Na-Cl-SO4 and Na-HCO3 types. Rock weathering serves as the main control on water chemistry, with hydrochemical components sourced largely from evaporite and carbonate dissolution. The sodium present in the water is likely attributable to silicate mineral dissolution or cation exchange processes. Cation exchange, with forward exchange dominant, is also a key hydrogeochemical process in the study area. SI results reveal that calcite and dolomite have reached saturation, while gypsum and halite remain undersaturated and tend to dissolve further. Irrigation suitability assessments indicate that most of the water quality in the Feicheng Coal Mine is excellent or good. A limited number of samples exhibited relatively high salinity, and most of them can be directly irrigated. To this end, this study proposes targeted treatment solutions, thus facilitating mine water development and utilization.
Lian et al. (Sat,) studied this question.