Optimization of Mine Drainage Capacity Using FEFLOW for the No. 14 Coal Seam of China’s Linnancang Coal Mine

Abstract

The hydrogeology of China’s Linnancang coal mine is very complicated. The aquifuge that lies between the no. 14 coal seam and the underlying K3 limestone aquifer is less than 20 m thick and the mine contains 10 known faults. The largest water inrush event exceeded 9.25 m3/min. Comprehensive modeling of the seepage field was undertaken to determine the appropriate water level in neighboring aquifers to reduce the likelihood of water inrush events. A 3-D hydrogeological model of the coal seam and associated aquifers was established to determine the characteristics of aquifers in the seepage field. The results, along with analysis of the existing mining conditions, showed that water levels will rise, but that if four dewatering wells were to be added in the mine area, the water levels would markedly decline. The water inflow forecast also showed that it is necessary to pump water and simulate water levels under different pumping pressure conditions. Based on this work, it appears that increasing the present drainage capacity by 30 % is economical and feasible.