Prediction of the Mine Water Inflow of Coal-Bearing Rock Series Based on Well Group Pumping

Abstract

Previous scholarly investigations have mainly concentrated on examining water intake, particularly within the specific domain of coal mines. Nevertheless, the scholarly discourse lacks significant research on predicting water inflow in environments with complex multi-layer mineral distributions. The Yanlong mining area is a complex mine containing coal and bauxite. Forecasting the water inflow of bauxite deposits is crucial for designing mining drainage and formulating a mining plan in a coal-bearing rock series mining area. The water inflow on the roof and floor of bauxite was studied with various numerical simulation and analytical methods (such as the big well method). The hydrogeological conceptual and numerical model of the mining area was established by the MODFLOW module in Groundwater Modeling System (GMS (7.1)) software, and the measured groundwater level was identified and verified in the model. The results show that the model average values of R2, Ens, and PBIAS are 0.86, 0.81 and 2.71, respectively, indicating that the established numerical simulation model can accurately forecast water inflow into the aquifer. Taking No. XII orebody in the eastern Songshan Mining area as an example, a virtual well group consisting of 12 wells was set up, and the numerical model forecast a water inflow of 71,500 m3/d from the Taiyuan Formation aquifer in the bauxite ore roof, which was lower than the value predicted by the large well method (72,786.66 m3/d). The numerical method predicted an average water inflow of 59,000 m3/d and a maximum water inflow of 82,600 m3/d from the Majiagou Formation in the bauxite ore floor. A dependence has been established that the numerical method estimates water inflow with accuracy. Additionally, the model predicts future mining water inflow, and also provides a standard framework for estimating inflow in similar mining conditions.