顺层定向长钻孔在厚煤层沿顶掘进工作面的应用

Application of bedding directional long borehole in thick coal-seam along top excavating face

厚煤层沿顶掘进工作面因煤层厚度大,采用普通钻孔不能有效抽采巷道底板煤体瓦斯,易造成工作面瓦斯超限,影响巷道掘进效率。以山西某煤矿主运大巷为试验巷道,通过分析掘进工作面瓦斯治理存在的问题,从抽采工艺参数设计、钻孔施工、抽采试验3个方面开展了顺层定向长钻孔在厚煤层沿顶掘进工作面的应用研究。现场试验结果表明:采用顺层定向长钻孔抽采工艺后,掘进期间主运大巷回风流及工作面瓦斯浓度整体较稳定,回风流平均瓦斯体积分数为0.34%,工作面平均瓦斯体积分数为0.16%,瓦斯涌出量明显下降,瓦斯治理效果显著;与采用普通钻孔抽采工艺相比,巷道掘进月进尺由150 m提高至240 m,工作面瓦斯体积分数由0.53%~0.79%降至0.25%~0.48%,回风流瓦斯体积分数由0.63%~0.96%降至0.28%~0.69%,掘进400 m巷道总用时由175 d减少至138 d,掘进效率得到有效提高。

Due to large thickness of coal seam along top excavating face,normal borehole cannot effectively extract coal gas from roadway floor,which is easy to cause gas exceeding limit on the excavating face and affect efficiency of roadway excavating.Taking main transport roadway of a coal mine in Shanxi Province as an tested roadway,application of bedding directional long borehole in thick coal-seam along top excavating face was researched from three aspects of parameters design of extraction technology,borehole construction and extraction test by analyzing problems existed in gas control on excavating face.The field test results show that after adopting extraction technology of bedding directional long borehole,gas concentration in return air flow and excavating face of the main transport roadway is stable on the whole during roadway excavating.The average gas volume fraction of the return air flow is 0.34%and the one of the excavating face is 0.16%.Gas emission decreases obviously,which shows definite gas control effect.Compared with extraction technology of normal borehole,roadway excavating is accelerated from 150 m per month to 240 m per month,gas volume fraction of the excavating face is decreased from 0.53%-0.79%to 0.25%-0.48%,gas volume fraction of the return air flow is decreased from 0.63%-0.96%to 0.28%-0.69%,and the total time consumption of excavating 400 m roadway is reduced from 175 d to 138 d,which show that excavating efficiency is improved effectively.