New technology of carbon dioxide fracturer applied to deep borehole pre-cracking blasting for seam permeability improvement

According to high gas drainage difficulty and low drainage rate problems of the low permeability seam,a new technology of carbon dioxide fracturer applied to the deep borehole pre-cracking blasting for seam permeability improvement was developed.With the theoretical analysis,site test and numerical simulation conducted,th e study results showed that the carbon dioxide fracturer applied to the deep borehole pre-cracking blasting in seam could promote the pore systematic development in the seam,could improve the permeability of the seam and could reach the enhanced gas drainage target. The underground test results of Beile Mine showed that After the fract uring operation conducted,borehole gas flow volume was increased by 3.8 ~ 6.7 times,the flow attenuation cofficient was reduced from 0.691 1 d-1to0.052 8 d-1,the seam permeability coefficient was increased by 26 times,the pre-cracking influence radius was reached to 4.5~ 5.7 m,the mine gas control effect was highly improved and the e conomic cost of gas control was reduced.Thus the mine mining and excavation replacement and safety production were ensured.