Study on the Methods of Eliminating Blank Zone of Mine Gas Drainage

In order to solve the effective influence range of the gas drainage borehole varied with the time, the inspection index of the coal and gas outburst effect f requently over the limit and other problems occurred during the mine gas drainage process, the paper had a study on the relationship between the gas drainage time, th e borehole space and the effective influence radius of gas drainage. The study showed that prolonged the gas drainage time and reduced the space of gas drainage bor ehole layout could effectively eliminate the outburst danger of the gas drainage region, but prolonged the gas drainage time would cause a balance lost in the mining, e xcavation and gas drainage of the mine.Therefore, according to the seam deposit conditions in Jiulishan Mine, the gas drainage borehole layout was enhanced in the 0 utburst seam and the space between the gas drainage boreholes was reduced from the traditional two times of the effective influence radius of gas drainage to 2 times. The results showed that reduce space of the gas drainage borehole layout could effectively eliminate the blank zone of the gas drainage, could reduce the over index ra te of the inspection index, could prevent and eliminate the danger of the coal and gas outburst during the mine gateway driving and could improve the driving speed of t he mine gateway.