Study on development height of water-conducting fracture zone in Banji Coal Mine

The 110504 working face in Banji Coal Mine with an average coal seam thickness of 6.1 m is a thick coal seam, above which has two water horizons at 1.6 m and 75 m. The overlying water horizons seriously affects the safety of mine production, and it is urgent to carry out the research on the development height of water conducting fissure zone. In this paper, UDEC 7.0 software is used to establish the mining model of 110504 working face and to simulate the evolution of water conducting fissure zone in the process of mining. The simulation results show that the immediate roof began to collapse when the working face advances to 50 m, and completely collapsed at 70 m. When it advances to 140 m, obvious caving zone and fracture zone are formed. When it advances to 190 m, the height of water conducting fissure zone reaches the maximum of 66 m, caving zone is 23 m, and fracture zone is 43 m. In addition, the network parallel electrical method is used in the head gate of 110504 working face. The field monitoring data show that the maximum influence distance of the abutment pressure is 58 m, the crack angle is 69.62°, the maximum height of the water conducting fissure zone is 73 m, the height of the caving zone is 27 m, and the height of the fracture zone is 46 m. The numerical simulation results are basically consistent with the electrical test results. The research results are of great significance to the study of the height of water conducting fracture zone under similar geological conditions.