底板贯穿型裂隙现场实测及其对瓦斯抽采的影响

高瓦斯煤层群利用保护层开采治理瓦斯效果显著,为煤矿安全生产提供了极大的保障,但是对于近距离和超近距离高瓦斯煤层群,在应用保护层开采技术时又产生保护层工作面瓦斯超限严重、采空区下方卸压区域瓦斯抽采浓度急剧下降等新的问题。以沙曲煤矿北翼二采区为实验背景,利用示踪气体实测层间贯穿型裂隙的发育时间、位置以及程度,验证了底板破坏深度定量计算的结果,定性分析了贯穿型裂隙对近距离煤层群瓦斯运移和瓦斯抽采的影响以此为依据调整并优化卸压瓦斯抽采技术参数,并通过现场应用验证,提高了瓦斯抽采率。

In-situ observation on the floor-connected crack field and its effects on methane extraction

The utilization of protective coal seam mining method，which provides a great guarantee for the safety producing in coal mine industry，has remarkable effect in high methane coal seam group.However，when it comes to the close and ultra-close high-methane coal seam group，the usage of protective coal seam mining method will face some new problems，such as the seriously high methane concentration in the protecting coal seam working face，significant decrease in the methane extraction concentration in the stress-released area under the gob，et al.Based on the geology and mining conditions of the second mining district in the north of Shaqu Coal Mine，via the tracer gas，authors detected the occurrence time，location and height of the connected crack field，and verified the results of the quantitative calculation of the damage depth of the floor.Authors also qualitatively analyzed the effects of the through cracks on both methane transport and methane extraction in close coal seam group.The above results were used to adjust and optimize the technical parameters for stress-released methane extraction，to improve the methane-extraction efficiency，and to provide safety environment for mine safety and highly efficient production.