A Study on the Technology of Inverted Bench Step Explosion and Smooth Blasting Roof Controlling
The industrial experiments are carried out to study the technology of inverted bench mine explosion by stage and smooth blasting roof controlling in broken rock wall.The explosion parameters and the inclined cut-step bench explosion method are determined based on the mine and rock mechanical parameters.The result shows that the maximum casting distance is 5.5～6.9 m,the loose coefficient is 1.55～1.62,bore hole utilization ratio is 89%~93%,the unit volume consumption of dynamite is 1.49~1.55 kg/m3.The roof and wall rock is mainly smooth,and the protuberance is less than 0.1 m,the bore trace is less than 30% and is distributed asymmetrically and discontinuously.The recommend reasonable smooth explosion parameters is that the bore spacing is 0.45~0.50 m,the minimum resistance distance is 0.5~0.6 m,linear charging density is 0.2 kg/m.Compared with the original program,the technique in this paper makes the amount of bore reducing 12%,the consumption of dynamite decreasing 18.4%～32.3%,and the bore hole utilization ratio up to 89%~93%.After the smooth explosion,the workload of risk-elimination and support is greatly reduced.The new technology is more advantageous in technology,economy and safety.