METHANE DRAINAGE EXPERIMENTAL RESEARCH FOR THE STRESS-RELIEF ROOF STRATUM OF WORKING FACE OF HIGH GAS COAL SEAM

A solution to the low gas drainageefficiency for lower-permeability gas-filled coal in China is suggestedbased on the theoretical analysis and model investigation of thestress-relief moving rules for the roof stratum during working. Withthis method, the gas is drained from the roof stratum with a strikelong-distance drill according to the developing characteristics of thecracks resulting from the stress relief of the mining roof stratum. Thecontribution of the roof stratum structure and the horizon of the key seamto the displacing rules of the roof stratum is analyzed, and the properzone for the strike long-distance drainage is provided. Judged from thepractical experience, the strike long-distance drainage in the roofstratum, with a drainage percentage of 20\% for working face, is anideal method for the coal seam with lower permeability.