Practices on Comprehensive Outburst Elimination Technology of Coal Mining Face in Outburst Seam

In order to rapidly eliminate outburst dangers of the regional coal mass in the coal mining face and to reduce the gas content of the air retuning flow duri ng the gateway driving period, a comprehensive gas drainage technical measures combined with crossed boreholes and grid boreholes were provided.A trial was condu cted in No.16021 coal mining face of Jiulishan Mine.The results showed that after the comprehensive technical measures conducted, the gas over limit rate of the outbu rst danger predicted for No. 16021 coal mining face was zero and the gas volume fraction of the air retuning flow in the transportation gateway was reduced from 0.8% b efore the comprehensive technical measures conducted to 0.4%. In comparison with the seam gas in the pre-drainage section with boreholes along in the mining seam, the gas drainage and outburst eliminated time could be reduced over 1/3.Therefore, the comprehensive drainage technical measure combined with the crossed borehol es and grid boreholes were feasible.