高突矿井大采高工作面瓦斯抽采技术及实践

为解决大采高厚煤层工作面回采期间瓦斯超限难题，应用顶板走向长钻孔中位钻孔和下临近层底板定向长钻孔等瓦斯抽采措施，对回采面瓦斯进行了多源头治理。通过对顶板走向长钻孔的抽采效果考察，确定其垂直层位为40±5 m范围、水平层位为50±10 m范围为最佳瓦斯抽采区域；中位钻孔合理的垂直层位为20 m左右，水平层位为45~50 m范围抽采效果最佳；下临近层底板定向长钻孔是拦截下部5#煤和7#煤向上部采掘空间涌出瓦斯的有效手段，其最佳的水平层位为距巷道轮廓线20 m范围，垂直层位为钻孔布置在下临近层煤层中。通过对3种不同瓦斯治理措施的综合评价考察，确定顶板走向长钻孔是治理回采面最为有效的措施，其抽采量占工作面回采期间总抽采量的79.6%，中位钻孔抽采和下临近层底板定向长钻孔抽采是回采面回采期间的辅助性措施。措施使用后，工作面上隅角瓦斯浓度保持在0.4%~0.6%之间，有效保证了工作面的安全高效回采。

Technology of gas extraction in working face with large mining height of high outburst mine and its practice

In order to solve the problem of gas over limit during the mining period in the working face with large mining height oin thick coal seam, the multi source gas control was carried out on the coal body in the mining face by using the gas extraction measures of long borehole along roof, median level borehole, directional long borehole in lower adjacent seam floor, etc. Through the investigation on the extraction effect of long borehole along roof, it was determined that the optimal gas extraction area of long borehole along roof was the vertical position of 40±5 m and the horizontal position of 50±10 m. For the median level borehole, the extraction effect was the best when the vertical position was about 20 m and the horizontal position was 45-50 m. The directional long borehole in lower adjacent seam floor was an effective mean to intercept the gas emission from the lower 5# coal and 7# coal to the upper mining space, its optimal horizontal position was 20 m away from the contour of roadway, and the vertical position was laying the borehole in the lower adjacent coal seam. Through the comprehensive evaluation of three different gas control measures, it was determined that the long borehole along roof was the most effective measure for controlling the mining face, and its extraction amount accounted for 79.6% of the total extraction amount during the mining period of working face. The median level borehole extraction and the directional long borehole extraction in lower adjacent seam floor were the auxiliary measures during the mining period of working face. After applying the measures, the gas concentration at upper corner of working face maintained between 0.4% and 0.6%, which effectively ensured the safe and efficient mining of the working face.