Analysis on Mining-induced Crack Development Features of Seam with Medium Thick Magmatic Rock Roof

With the study on the overburden strata features above No. 4414 coal mining face in Zhuzhuang Mine, the FLAC simulation software was applied to the simulation of the deformation failure law of the medium thick magmatic rock roof under the mining activities. The simulation results showed that the roof falling height in the goaf of No.亚4414 coal mining face was about 6 m, the max height of the cracks was developed to the top of the igneous rock, which was 2528 m in distance to the seam floor.In comparison with the neighbour coal mining faces, the gas drainage rate with the high level boreholes drilled at the top corner would be increased by 2 tim es and could improve the safety production status of the coal mining face.