Yuheng Coalfield is a typical Jurassic coal mine with a multi-layer groundwater system but it is exposed to an arid and semi-arid climate with scarce water resources. Thus, the ecological environment is extremely vulnerable, and the groundwater chemistry and quality may be influenced by multiple factors. In this study, the self-organizing map calculations in combination with traditional multivariate statistical methods were used to investigate groundwater chemistry and quality. Thirty-nine groundwater samples collected from different aquifers were divided into four clusters. Cluster I (shallow water consisting of surface water, Quaternary and Luohe group groundwater) was dominated by Ca-HCO₃ and Ca-Na + K-HCO₃ types, Cluster II (mainly Zhiluo group groundwater) consisted of Ca-Na + K-SO₄ and Na + K-Ca-SO₄ types, Cluster III (deep water consisting of Zhiluo and Yan'an group groundwater and mine water) was of the Na + K-Ca-SO₄ type, while Cluster IV (mine water) was the Na + K-SO₄ type. The dominant water-rock interactions controlling groundwater chemistry and quality were cation exchange and dissolution/precipitation of carbonate, gypsum and halite. Based on the pumping test results, the good hydrological properties and hydraulic connection between aquifers also affected groundwater chemistry and quality. The findings of this study will help inform the sustainable development and protection of groundwater resources in the study area and other coalfields.

于恒煤田是典型的侏罗纪煤矿，具有多层地下水系统，但暴露于干旱和半干旱气候，水资源稀缺。因此，生态环境极为脆弱，地下水的化学性质和质量可能受到多种因素的影响。在这项研究中，自组织图计算结合传统的多元统计方法被用于调查地下水的化学和质量。从不同含水层收集的三十九个地下水样本被分为四个簇。团簇I（由地表水，第四纪和he河组地下水组成的浅水）以Ca-HCO ₃和Ca-Na + K-HCO _3为主。类型II，聚类II（主要是直罗组地下水）由Ca-Na + K-SO ₄和Na + K-Ca-SO ₄类型组成，聚类III（深水由直洛和延安组地下水和矿山水组成）为Na + K-Ca-SO ₄类型，而簇IV（矿泉水）是Na + K-SO ₄类型。控制地下水化学和水质的主要水-岩石相互作用是阳离子交换以及碳酸盐，石膏和石盐的溶解/沉淀。根据抽水试验结果，良好的水文特性和含水层之间的水力联系也影响了地下水的化学性质和质量。这项研究的结果将有助于为研究区域和其他煤田的地下水资源的可持续开发和保护提供信息。