Optimized Design of Seam Gas Pre-drainage Plan

In order to solve the gas content over limit and the coal and gas outburst problems of the excavation and mining faces during the seam gas drainage and to improve the gas drainage effect of the coal mining face,taking the No.14221 coal mining face of Xin'an Mine as the study object,a gas pre-drainage experiment with different borehole space in and along the seam was conducted.The variation law of the borehole gas drainage value with the time and the relationship between the pre-drainage rate and the time under the different borehole space were investigated.The results showed when the space of the deep drainage boreholes was 1.5 m,the gas drainage effect would be 1.24 times higher than the 2.5 m space of the drainage borehole.Meanwhile,when the parallel boreholes in and along the seam in Xin'an Mine changed to the layout of the inclined boreholes,the borehole drainage concentration was improved by 0.32 times and the good gas drainage effect was obtained.