中国矿山工程

During underground mining, a safety pillar with a certain thickness is often left at certain interval to work together with the surrounding rock for supporting the overlying strata to maintain the structure of the stope and enabling a safe extraction of the ore body. The southeast ore body of Chambishi Copper Mine adopts the strip mining approach of pre-cut headspace open stoping with subsequent backfilling, where extraction is carried out in two steps with 25m-thick safety pillars left in place between the panels. To analyze the stability of the safety pillars left between the panels and provide a reference for later optimization of mining, this paper uses the FLAC^3D numerical simulation software to analyze the stress, displacement and plastic zones of the 25m, 23m, 21m, 19m, 17m and 15m thick pillars respectively after the excavation of the two-step stope is completed. The research results show that pillars with a thickness of 19m and more can meet the stability requirements. Meanwhile on-site observation shows that after the extraction of the two-step stope is completed, the 25m-thick pillars left between the panels have a perfect structure, and no phenomenon such as wall caving has ever occurred, indicating that their stability is excellent.