Development of a hydrodynamic method for degassing of gas-saturated flat-lying coal seams

Deterioration of geological and mining conditions for underground extraction of coal deposits with increasing depth leads to significant gas release into mine workings, reaching 45 m3 or more per 1 ton of coal mined at some mines. Existing standard methods for degassing of stressed coal seams often do not provide required degassing efficiency of 50 % and more for rhythmic operation of production faces. In some conditions, open-hole degassing efficiency of 30 % can be achieved, which allows to increase output per face up to 1,000 tpd with gas release from seam up to 5 m3/min. However, at depths of 1,000-1,300 m and high-performance operation of longwall sets of equipment, gas release can reach 170 m3/min that causes face stoppages due to gas hazard and slows down the pace of stope development and stoping. In addition, preliminary seam degassing requires rather long time. Modern achievements in the field of rock hydraulic fracturing are the basis for the development of low-energy safe and environmentally friendly technologies for degassing of stressed gas-saturated coal seams...