Abstract:Purpose: Aiming at the problem of low comprehensive utilization efficiency of coal waste in China, this paper aims to study the influence of reservoir coal pillar dam on the evolution of mine water quality. Method: In this paper, the long-flame coal and different mine water sources in the low-rank coal of Wulanmulun Coal Mine are taken as an example. The coal-water interaction process is simulated by the indoor static immersion experiment. From the perspective of water chemical composition, correlation analysis, factor analysis, and other statistical methods are used to explore the control factors of different mine water quality evolution under the influence of long-flame coal. Result: After analysis, it was found that the initial hydrochemical types of the four types of water samples were inconsistent, and evolved into HCO3-SO4-Na-Ca type and SO4-HCO3-Na-Ca type after reaction. The cumulative variance contribution rates of the main control factors of the four types of water samples were 82.52 %, 80.07 %, 80.68 %, and 80.02 %, respectively, which all met the principle that the cumulative variance contribution exceeded 80 %. Conclusion: Long flame coal has different effects on surface water and groundwater. The synergistic effect of coal-water mainly includes the dissolution of various minerals (carbonate rock, silicate rock, sulfate rock salt, etc.) and cation exchange. The main factors of surface water and groundwater quality evolution are the dissolution of carbonate minerals and cation exchange, respectively.