Abstract: In China low permeability high gas coal are universal existence, In order to improve the permeability coefficient of the coal and achieve the purpose of increase gas pumping. The orifice blasting presplitting techniques were used in ShangShe 15103 coal face. By field test and contrast test, the effectiveness of the orifice blasting presplitting techniques to increase gas pumping has been verified. And by adding damping device to burst test, the shock wave generated by blasting has reduced, at the same time weakened the damaging effects of shock waves on the coal wall at edge of the hole, which not only optimized the blasting process, but also satisfied the practical needs of increase pumping gas. The results show that when loading dose of level 3 emulsion explosive filled in the hole were 0.8-1kg, by adding protective barrel at the orifices in bursting test, after the test, compared with the original value the gas drainage improved sharply. drainage negative pressure declined, both the volume and the pure gas drainage volume substantial increased, The gas density also boosted, drainage radius increased from 1.5m to 3m, the effect of gas drainage was evident. Provided support in using orifice blasting techniques to increase gas pumping in coal mine.

Key words: orifice blasting presplitting, increase gas pumping, level 3 emulsion explosive, bursting test, shock wave