Repair of a deep-mine permanent access tunnel using bolt, mesh and shotcrete

Some of the supports in the permanent access tunnel of the Jiulongkou Coal Mine had failed and large deformations were observed. This had a serious impact on the safety and production of the mine. Damaged tunnels were usually repaired using steel sets or timbers in the past. Based on analysis, a new support measure was adopted using bolt, mesh and shotcrete. Repair work carried out in a 70-m-long tunnel showed that the supporting approach and techniques were satisfactory and successful.