[Characteristics of Surface Water and Groundwater Chemistry and Controlling Factors in the Centralized Coal Mining Area of the Yellow River at Several Bends in the River].

Water resources in the mining area are an important foundation for maintaining the normal operation of mining activities and supporting the production and life of the surrounding residents， and the rational utilization and protection of water resources are of great significance to the ecological safety and sustainable development of the mining area. Surface water and groundwater in the centralized coal mining area of the Yellow River's Jizi Bend were selected as the research objects. Based on the results of hydrochemical testing of 37 sets of water samples collected in September 2023 （24 sets for groundwater and 13 sets for surface water）， mathematical statistics， Piper's trilinear diagram， Gibbs' diagram， ion ratio， mixing simulation， and PCA-APCS-MLR source analysis were utilized to investigate the chemical characteristics and controlling factors of groundwater and surface water in the centralized coal mining area of the Yellow River at several bends and to quantitatively analyze the sources of the hydrochemical components. The results showed that： the overall water environment in the study area was weakly alkaline， groundwater was dominated by freshwater， and surface water was dominated by brackish water and freshwater. Groundwater in the study area was dominated by HCO3-Ca type and HCO3-Na type， while surface water was dominated by Cl·SO4-Na and HCO3·Cl-Na type. The hydrochemical formation process of surface water and groundwater was dominated by water-rock action and cation-exchange action， in which the weathering and dissolution of silicate rocks dominated. The water chemistry of groundwater in the mixing simulation was lower than that of surface water， and the mixing had a diluting effect on the water chemistry of surface water. PCA-APCS-MLR source analysis identified three main controlling factors， namely， the dissolution-filtration-enrichment factor， primary geologic factor， and human activity factor， among which， the dissolution-filtration-enrichment factor was the first controlling factor for the formation of water chemistry. The results of the analysis can provide a scientific basis for the rational development and utilization of water resources in the mining area.