Discussion on controlling factors of hydrogeochemistry and hydraulic connections of groundwater in different mining districts

To explore the controlling factors of the hydrochemistry and hydraulic connections of groundwater in three mining districts, 45 water samples from three mining districts (Nos. 31, 32 and 42) in the Peigou Coal Mine are analyzed. The hydrogeochemical compositions of the three mining districts are analyzed, and the water-rock interaction and controlling factors of the hydrogeochemistry of the groundwater are discussed by examining the ionic composition (ion ratio) and using a factor analysis. Then, the hydraulic connection is determined by conducting cluster and discriminant analyses. Finally, a model that identifies the source of the water inrush of the three mining districts is provided. The results show the controlling factors of the hydrogeochemistry in the three mining districts. And it is speculated that the hydraulic connection between the Nos. 31 and 42 mining districts is higher than that between the Nos. 31 and 32 mining districts. It is hypothesized that there may be an obscured tunnel between the Nos. 31 and 42 mining districts, which is connected through the Fushanzhai fault. Based on the water source identification model of mining districts, the groundwater recharge relationship of three mining districts is inverted by analyzing the causes of misjudgment and comparing with groundwater pulse in different years. The proposed method provides a new idea for correctly recognizing the groundwater circulation conditions under the influence of mining.