Effect of low density explosives on key indicators in surface coal seam blasting

In order to improve the blasting effect of coal-rock, on the base of rock blasting theory, blasting mechanism of coal-rock and the way to reduce the crushing zone of blasting are analyzed, and low-density explosive is proposed for coal-rock blasting in surface coal mine.The effects of low-density explosives on the bulk rate, extraction efficiency, lump coal rate and foamed coal rate are studied by testing the coal-rock blasting of different charge structures and explosive charge of low-density explosives.The results show that the density of low-density explosive charge is low, the continuous charge can be achieved in the blast hole, which is beneficial to reduce the explosive consumption, energy transmission is more uniform than other explosives.In a certain extent, explosive unit consumption is proportional to the mining efficiency, bulk rate, lump coal rate and foam coal ratio, and the relationship among them is comprehensively optimized.The optimum range is 0.171-0.190 kg/m³, which provides the basis for engineering blasting design.