Study on High efficiency pre-cracking Technology of Coal seam

More than 90% of coal seams in our country are low permeability coal seams, which seriously affects the safety of mine production. Therefore, a kind of solid pre-splitting agent is studied in this project, and the effect of coal seam pre-splitting test is studied in Nantun coal mine. This paper introduces the action principle of the solid pre-splitting agent, and then tests and studies the fracture pore characteristics of the coal in Nantun coal mine, selects the reasonable pre-crack drilling arrangement scheme, carries on the coal seam pre-cracking experiment and collects the results. Through the comparison of the pre-splitting effect of coal seam, it is concluded that the pre-cracking radius of this technology can reach 25 meters, which makes the primary and secondary fractures in the coal body expand, the coal body joints, and the fracture penetration network, thus increasing the permeability of the coal seam. At the same time, a large number of uniform cracks were produced because of the pre-splitting, which improved the lump coal rate. The pre-splitting reduces the coal dust concentration and the strength of the coal body, and reduces the energy consumption of cutting ratio, thus realizing the energy-saving and clean mining of coal mine. (paper)