长平矿为高瓦斯矿井，经测定煤层瓦斯含量最高达到15 m3/t，百米钻孔瓦斯流量衰减系数0.1101 d-1～0.1137 d-1，透气性系数0.0116 m2·（MPa-2·d-1）～0.0520 m2·（MPa-2·d-1），属于难抽放煤层，顺层钻孔预抽存在衰减快、抽放量小、钻孔成空率低等问题。针对以上问题，采用底抽巷穿层钻孔预抽煤巷条带瓦斯，从地底条件、岩层赋存规律、钻孔施工效率、防治水等因素考虑，对3号煤底抽巷的层位进行合理选择，确保底抽巷安全掘进、钻孔高效施工。%Changping mine is a high-gas mine. It is determined as a difficult-drainage coal seam with 15m3/t of maximum gas content, 0.1101 d-1~0.1137 d-1 of attenuation coefficient of gas flow 100-meter drilling, and 0.011 6 m2/(MPa2·d)~0.052 0 m2/(MPa2·d)of permeability coefficient. There are problems like fast attenuation, small quantity of drainage, and low forming rate of boreholes when pre-draining with bedding boreholes. To solve the problems, the pre-drainage of stripe gas by layer-through borehole in end-located drainage roadway was used. According to underground condition, occurrence patter of strata, construction efficiency of boreholes, and water control, the position of No.3 drainage roadway was selected to ensure the safe driving of the roadway and the efficient construction of the boreholes.
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