Abstract： In order to determine whether the mining of No.9 coal seam in Cilinshan Mine would make the water accumulated in goaf of No.3 coal seam above inrush into working face, the empirical formula and numerical simulation method were used. It was predicted that the development height of the rock water conduction fracture zone caused by the original mining of No.9 coal seam was 65.96 ~ 69.6 m. The failure depth of No.3 coal seam floor was not less than 21 m, the average thickness of the rock layer between No.3 coal seam and No.5 coal seam was 88.02 m, and the thickness of the interlayer rock layer was slightly less than the sum of the depth of the water conduction fracture zone of No. 9 coal seam and the failure zone of No. 3 coal seam floor, which was measured by underground downward hole water pressure test method. The mining of No. 9 coal seam might make the water accumulated in goaf of No.3 coal seam above inrush into working face. It was necessary to drain the water damage in the overlying goaf before the mining of No.9101 first mining face.
