According to the geological conditions of Baijiao Mine and coal seam occurrence situation,the mechanism of hydraulic fracturing is analyzed and also the parameters are calculated.The industrial experiment was carried out in the 238 bottom drainage lane and the effect of fracturing was investigated.The results show that the effective radius of hydraulic fracturing is 80 m and the hydraulic fracturing makes the average single hole gas drainage quantity increased by 6.7 times,the drilling work reduced 1/3 and ...