DEGASSING METHOD OF SET OF CONTIGUOUS COAL BEDS FOR BARRIER METHOD Russian patent published in 2008 - IPC E21F7/00 

FIELD: mining engineering.

SUBSTANCE: invention falls within the realms of mining industry, particularly degassing of a set of contiguous coal beds for a barrier method. The method involves determination of a zone with the highest level of gas accumulation. Discharge bags are formed in this zone during stopped excavation of the mined bed, drilling of a diverted well from the surface. The working part of the hole is directed parallel to the surface of the beds and located in the discharge bags under screening rocks. The well mouth is sealed and the coal-bearing mass is discharged with a subsequent gas suction from the well by means of vacuum pumps. Location of a diverted well on the surface is selected between two extraction pillars of the mined bed intended for mining. The diverted well is made multilateral, namely, after drilling of a given working part of the diverted well positioned along one of the extraction pillars, its other working part is additionally made and directed in the opposite direction in reference to the latter and along the other extraction pillar. Afterwards, each of the working parts of the diverted well is branched for two bores minimum. Each of these bores is directed parallel to the working part of the well in the plane of the discharge bags. When preparing extraction pillars for a stopped excavation in the mined bed, a step-by-step discharging of the coal-bearing mass is taking place. For this purpose, at first a mechanical impact is directed toward the coal-bearing mass through the working parts of the multilateral well, for instance, by means of infusing compressed water in a hydroimpulsive mode. Then, vacuum pumps are engaged for the well and gas issuing from the cracks of the discharged coal-bearing layer in the area of location of the diverted well working parts is sucked off. Afterwards, the development drifts lining the extraction pillars are used for drilling of relief wells directed to the diverted well working parts and the mechanical impact is implemented through them on the coal-bearing mass, for example by means of camouflet blasting. This blasting provides development of an additional system of cracks-collectors in the coal-bearing mass that channel the gas toward the diverted well, which is then sucked off as it enters the well. Then, during the coal-face work in the mined bed, discharging of the coal-bearing mass continues due to rocks shift, and the gas from the destructed coal-bearing mass issues into the discharge bags formed during the coal-face work above the undermined bed. After completing the coal-face work in the extraction pillars of the mined bed the gas continues being sucked off from the undermined coal-bearing mass with a simultaneous extraction of the undermined bed and gas suction from the empty space of the bed. Moreover, gas continues being sucked off from the diverted well even after extraction of coal beds in a set. Besides, before mining of the next extraction pillars of the mined bed, another multilateral well is drilled and the work cycle for discharging and degassing of a coal-bearing mass is repeated.

EFFECT: increase in coal extraction from mining faces providing operations safety in terms of presence of the natural gas.

3 cl, 10 dwg