Experimental Study of Pre-splitting Blasting Enhancing Pre- drainage Rate of Low Permeability Heading Face

Abstract

Taking the heading face of a coal mine as an example, the test of deep-hole pre-splitting blasting was processed. The amount of gas draining after pre-splitting was compared to the amount of direct drainage, and the effective radius of drainage was surveyed. The test results showed that the drainage rate of K1 coal seam reached 37.13%, which reduced the drainage time by 60%, 10 days after pre-splitting, and the gas desorption index exceed the standards until the fifth blasting. The drainage rate of K4 needed 12 days to reach 34.28%, which reduced the drainage time by 60%, and the gas desorption index exceed the standards when the third blasting processed. Obviously, the effect of gas drainage was improved by pre-splitting blasting. The effective drainage radius of K1 and K4 were 4.5 m and 5.2 m respectively after pre-splitting blasting.