Permeability Improved Technology and Practices with Deep Borehole Energy Accumulation Blasting in Low Permeability Seam

According to the low gas drainage rate of the low permeability seam in Songshuzhen Mine,based on the study on the mine gas geology,the paper analyzed the seam fracturing mechanism with the energy accumulation blasting and blasting fracture was divided into crush zone,crack developed zone and crack propagating zone.Blast hole,charging and sealing technology were designed,and energy accumulation blasting and permeability improving technology of deep borehole was applied.The site application results showed that,after the energy accumulation blasting conducted,the average gas drainage density of the borehole was increased by 1.70-3.21 times higher than before the blasting conducted.In the blasting influence zone,the average gas drainage density value was 11.26%,which was 2.21 times higher than the no blasting influence zone.With the explosive loading length increased,the blasting and permeability improving effect would be more obvious.