Study on Optimum Technology of Gas Control in Contiguous Outburst Coal Seams

During mining of contiguous outburst coal seams, a large amount of pressure relief gas near the seam was poured into the working face through roof and floor fractures. Consequently, substantial gas is emitted to the working face, leading to frequent alarm of methane sensors in the return air corner and in the return airway, Which seriously restricts the safe production of mines. In this study, through analysis and demonstration of several gas control schemes, the scheme took the whole coal seam group as a control unit and regarded the weak outburst coal seam with relatively small thickness and low gas content as the key protective seam. Meanwhile, in the scheme, three-dimensional borehole drainage was carried out to realize progressive protection. The field practice results showed that the gas drainage rate of the working face of protective seam reached over 90%; the gas concentration in the return air corner fell to below 0.6%; the maximum gas concentration in the return air flow was 0.15%; Meanwhile, the scheme fundamentally solved the gas-induced safety threats during the recovery of working face of protected seam.