Room Type Void Zone Overlying Coal Seam Longwall Mining Feasibility Study

8 coal seam of Hu long gou coal mine area use adopting 9m leaving 6m which is room and pillar type method is Stoping finished. So the upside of 5 coal seam is in pedal empty mining status 5 coal seam longwall is will use fully-mechanized sublevel caving mining scheme.At first, this article show a detailed site investigation and analysis of roof and floor lithology, structure and stability of 8 and 5 coal seam, and use a variety of theoretical methods, typing room and the roof rock after mining of coal deformation of 5, and analyze the stability of coal pillar Secondly, based on the specific conditions of the mine, a three-dimensional FLAC 3D model is established.5 coal seam floor of the sink, tilt, curvature variation is predicted at 8 different coal mining width to stay wide, without caving and caving ladder and other 8 cases. Then simulate 5 coal caving long wall mining face and analyze 5 coal seam floor,8 coal pillar cavity pressure and deformation when pushed from the different progress to predict affect of 5 coal mining to 8 empty area of coal pillar stability. Finally, propose five coal-face tunneling process to the depth of floor damage and failure detection program.The research of project has important application value for the safety of empty area of the tread above mining coal.