TEST AND STUDY ON INCREASING THE BLASTING EFFICIENCY OF UNDERHAND CUTTING AND FILLING METHOD IN HEXAGON STOPE IN LONGSHOU MINE

The blasting operation of underhand cutting and filling method in hexagon stope in Longshou Mine has been inefficient over many years resulted by the operation schema of "lower footage,multi-circular driving".Based on the classification of drillability and blastability on rock masses in Longshou mine,the model of parallel cut blasting with large diameter empty hole and the approach of full-face blasting were designed in this paper,otherwise,the blasting parameters about cut holes and post-blasting holes were derived out using fracture mechanics.The result of full-scale tests in Longshou mine showed that the hole utilization ratio reached over 90 percent and the blasting efficiency was increased over 20 percent than its previous performance,Meanwhile,the average ore amount of once blasting was 120 tons on the same of explosive consumption.