Research And Application Of Permeability Enhancement Technology For Deep-hole Presplitting Blasting In Dawan Coal Mine

In the working face of low permeability gas outburst coal seam,the number of gas predrilling holes is more,the borehole pre pumping time is long,the gas drainage concentration and pure quantity are low,the working face outburst prevention time is long,and the mining and mining connection is tight.Gas drainage is not up to standard makes working face advancing slowly,gas overrun,gas explosion and the danger of coal and gas outburst increased.The improvement of gas drainage efficiency and gas drainage concentration of the outburst coal seam is beneficial to improve the mine output and production efficiency,improve the working environment and safety conditions of the workers,and realize the safe and efficient mining with low permeability to the outburst coal seam.This paper takes Guizhou Shuicheng mining Limited by Share Ltd Dawan Coal Mine as engineering background,through theoretical analysis,laboratory research,numerical simulation and field test,analyzes the key technology of Permeability Enhancement for Deep-hole Presplitting Blasting in the coal seam.The research shows that under the combined action of explosion pressure wave,gas explosion,control hole and gas pressure,the deep-hole presplitting blasting in this coal seam can obviously increase the permeability of the coal seam.The control hole is free of charge and has the directional compensation function to the blasting.After the blasting,the joint and the "zigzag" fissure network are formed around the blasting hole,so that the permeability of the coal seam is improved.The local blasting equipment and forward uncoupling charge structure are adopted to seal the hole,the sealing depth is 8?15m,and the large series is detonated once,which is beneficial to the safety management and the antireflection construction.The results of the study in the West wells X10901-3 working face section driftway Dawan Coal Mine industrial test and application show that the deep-hole presplitting blasting control area,coal seam permeability coefficient increased 5.8?6.8 times,increasing permeability of effective influence radius of 6m presplitting blasting;After the Presplitting anti-reflection,the engineering amount of the drainage hole is reduced by half,and the pumping standard period is shortened to the original 1/3;After Presplitting anti-reflection single-hole gas concentration,average pure quantity increase is 3.72 times and 3.79 times than that before Presplitting,effective elimination of gas overrun,gas explosion and coal and gas outburst potential risks,technical and economic and social benefits are obvious.