Optimization Study Of The Second Step Mining Deep-hole Blasting Parameters In The Filling Mining Method

In the second step mining process of open subsequent filling mining method, the backfill is easy to be destroied due to the blasting effect. It often causes the backfill pieced and collapsed which affect the stability of the stope and backfill. The reasonable blasting parameters can average the ore crushed,decrease the block rate, maintain the stability of the backfill, reduce the risk of the filling and control the blasting damage which is an important issue of the filling mining method.Based on the Wu Zhuang filling mining engineering project, the numerical simulation, field test and monitor were performed to optimized the deep hole blasting parameters.Based on the theoretical analysis of the explosion stress waves propagating characteristics and attenuation law, the explosive blast load of non-coupling charging and coupling charging in rock and backfill were investigated.Geological conditions of blasting engineering were surveyed and analyzed to optimized the deep hole blasting parameters. The degree of ore blasting was classified as difficult to moderate. According to the experiments, theoretical analysis and field observation, the optimum sand filling ratio was 1:6when the strength, independence, transportation and dewatering were taken into account. The sand filling was in good globality and high stability.Based on the rock mechanical properties and blasting parameters, numerical simulation was performed to established the model of the different hole-bottom burden fan-patterned hole and different side hole burden parallel hole blasting which explored the influence of the blasting on the damage of the backfill. The simulation results indicated that the vibration velocity and stress decreased with the increase of the hole-bottom burden fan-patterned hole and the side hole burden parallel hole that decreased the damage of the filling body.Based on the numerical simulation results, the 0.5m hole-bottom burden of field fan hole blasting and 0.7m edge hole distance of field parallel hole blasting experiments were performed. Moreover, the field experiments were observed using VS150 three-dimensional scanning detection system. The experiment results indicated that the surface of the filling body is smooth and no collapse which concluded the optimized parallel holes and the fan-patterned holes blasting parameters that could guide the underground blasting construction in future.