Experimental study on coal mine excavation based on bundle-holes underholing blasting tecnology

Traditional drilling and blasting method with low efficiency was widely used in the domestic coal mine excavation,which is difficult to adapt to the needs of strengthening coal mining,so the research of improving the efficiency of drilling and blasting method is of great significance to the coal mine production.Here from the angle of increasing hole length and improving underholing effect,the bundle medium-length hole blasting method is selected and designed,with playing advantage of medium-length hole underholing,and realizing the full use of the blasting hole though using bundle holes optimal buried deep under the condition of equivalent spherical funnel,which improve the underholing effect,and thus rise the cycle speed and efficiency of excavation.Experiments show that with traditional shallow hole wedge underholing compared,bundle medium-length hole blasting excavation of every footage cycle increased by 45%,the effect is remarkable.