Water Inrush in Roof Bed Separation Due to Extra-Thick Seam Mining and Its Control

This paper takes a fully caving face in a coal mine in western China as an example and analyzes several water-inrush cases in the roof-bed separation of the first mining face. Various causes and characteristics of water inrush in bed separation are also analyzed. The bed separation closure distance in the working face mining was calculated using the thin-slab theory. The results show that the roof-bed separation first closure distance was about 250–300 m, and the cycle closure distance was about 150–175 m. Moreover, a water-in-bed separation-disaster prevention method was proposed by conducting a ground straight-through diversion borehole, which is used for dewatering in bed separation. Furthermore, the groundwater level supplying the roof-bed separation was observed. The results show that the ground straight-through diversion borehole was good for dewatering the bed separation before the closure of the bed separation. This measure eliminated the danger of water inrush in roof-bed separation, which ensures the safe mining of the working face. This study, through the integration of theoretical analysis and engineering practice, proposes and validates a prevention and control technology for water hazards in roof-bed separation based on ground straight-through diversion boreholes, providing a reliable technical approach for safe mining under similar geological conditions.