Research and engineering practice of precise gas drainage technology with borehole to replace roadway in Mabao Coal Industry mining area of Jinneng Group

In order to solve the problem of gas control in the upper corner of the mining stope where the gas emission amount is more than 20 m³/min, based on the dynamic migration law of the overburden rock layer on the roof during the mining process and field investigation, it is determined that the enrichment area of pressure relief is from 15 m to 38 m away from the roof and from 8 m to 40 m away from the return air roadway, and the directional drilling machine is used to accurately drill boreholes for stable and efficient extraction. The experiment was carried out on 5 directional long holes in 15203 fully mechanized mining face of Mabao Coal Industry. Within 70 days of extraction, the maximum pure flow rate of single-hole gas drainage is 10.41 m³/min, the pure flow rate of gas drainage in the drilling field is up to 15.00 m³/min, the gas extraction effect is about 3 times to 4 times as good as ordinary drilling, the construction time is about 2/3 shorter than that of the high drainage roadway, and the engineering cost is saved by about 3/4, which not only effectively relieves the joint tension of coal drainage, excavation and mining, but also realizes the purpose of reducing cost and increasing efficiency of mine gas control.