Bolt-net-cable-beam Support Technology of Mining Gateway Under Goaf in Close Distance Coal Seams

According to the engineering project of lower coal seam roadway support of close distance coal seams in a mine, FLAC^3D is used to analyzed reasonable roadway position in the lower coal seam. Based on the poor integrity of the proof strata by effect of upper and lower coal seam mining, the combination of high strength prestressed anchor, metal net and W steel and steel pallet or short cage type cable, the cable girder anchor steel beam were tested in field. The results of mine pressure observation showed that the supporting scheme can effectively control the development of vertical fracture, and form the optimal combination beam state of roof rock, which achieved good supporting effect.