Stope Structural Parameters Optimization for Open Stoping with Subsequent Backfilling on the Basis of FLAC~(2D)

To investigate stope stabilities under conditions of different structural parameters and mining steps in open stope mining with sequent backfilling for flat- lying medium- thick deposit,FLAC2Dsoftware was introduced to simulate the stress,settlement and plastic zone distribution. The two- dimensional simulations involved three mining steps where stope width was set as 32m,36m and 40m,respectively. Results showed that the ideal elastic- plastic model for filling materials and strain softening model for ore and rocks were applicable to skarn deposits. Stope stabilities displayed differently under conditions of different mining disturbances and back spans. The maximum principle stress,minimum principle stress,plastic zones and roof settlements met the safety requirements when stope width was less than 36m along the strike. Additionally,the optimized stope structural parameters were proved safe and economically by in situ operations. The optimized alternative involved 36m stope width,wherein room width was 31m and pillar width was 5m.