Scheme Design And Application Of Deep Hole Blasting Technology In Hard Rock Roof

China is a big country of energy consumption.In the energy structure of our country,the demand of coal accounts for about 65%of the total energy structure.Due to the large-scale exploitation of coal,the gas drainage problem has been plagued by the majority of coal mines in china.With the depth of coal mining increased gradually,under the influence of high ground stress in the deep coal seam permeability,coal seam gas volume,drainage process gas drainage effect of traditional gas,in fully mechanized mining face together,to bring great security risk in coal mine production.To solve the problem of deep coal gas and prone to aggregation,difficult to discharge,introduced a set of comprehensive management of exhaust,goaf buried pipe and high drainage roadway gas process.Antireflection of coal seam gas drainage technology for soft coal seam roof fracturing effect,introducing high layer gas drainage technology,and optimization of deep hole presplitting blasting blasting scheme,the gas permeability after the extraction efficiency is greatly improved,the effect of extraction has obvious change.The blasting cracked roof can improve the permeability of coal seam,weaken the roof,release the energy inside the roof,improve the roof caving,and make the hard and hard roof change into the roof.In this paper,based on the 1321(1)working face of Dingji coal mine,the gas concentration in the working face has been kept stable and no gas overrun phenomenon has been found through the combination of the three methods.The scheme design of three blasting,blasting with spacing of 25m,compares the wind gas after blasting,goaf gas drainage pipe,high drainage roadway gas drainage effect,high drainage roadway gas drainage effect is most obvious,during a period of forty-eighth working days to Seventy-eighth working days,high pumping roadway concentration increased sharply,the average concentration is about 37.6%,after blasting than before blasting increased by nearly 40%,the average recovery of pure smoke after blasting quantity is 35.6m3/min,extraction of pure quantity after blasting than before blasting increased by about 20%;and goaf gas drainage pipe buried in blasting before and after the change is not obvious,only in three working days drainage concentration is greatly improved,the gas concentration in the exhaust gas after blasting in the return air lane also decreased,blasting induced permeability after crack has greatly improved.