Abstract:
To meet the need of “zero” gas overrun in low permeability coal seam of high outburst coal mine, the influence radius of deep hole pre-splitting blasting is studied by theoretical calculation and field test. Through the field gas extraction flow and concentration monitoring, we analyze permeability improvement effect by deep hole pre-splitting blasting. The results show that the theory radius of crushing zone by deep hole pre-splitting blasting is up to 4.0 to 6.3 m, and the radius of crack area is up to 7.8 to 12.1 m, and the field test shows that deep hole pre-splitting blasting influence scope is more than 9 m; the drainage effect of blasting and permeability improvement is inversely proportional with the distance of blast hole distance; deep hole pre-splitting blasting technology can biggest increase the gas drainage pure flow of 9.27 times and the average increase of gas drainage pure flow 4.96 times; the application shows that deep hole pre-splitting blasting can improve the gas drainage efficiency.