近距离煤层群底抽巷瓦斯抽采实验研究

针对山西焦煤集团屯兰矿近距离煤层群开采过程中,采煤工作面底板瓦斯超限的问题,通过对近距离煤层群采掘工作面底板煤岩增透机理分析及回采工作面邻近层瓦斯涌出量计算,得出18205工作面底板瓦斯涌出量增大原因:18205工作面底板受采动影响,煤岩体形成裂隙带和卸压带,煤岩透气性系数成百倍增加,渗透率增大,为下邻近层瓦斯涌出提供了通道;下邻近层9#煤层瓦斯涌出量占18205工作面瓦斯涌出量的比例高达11.4﹪。结合理论分析、计算及开采条件,进行了底抽巷瓦斯抽采实验研究。结果表明:底板瓦斯浓度由0.46%降至0.1%,瓦斯抽放率提高了17%,矿井通风能力得到了提升。

Study on gas drainage from coal floor of close distance seam group

Aimed at the serious gas overrunning of coal floor at No.18205 working face during mining in the close distance seam group of Tunlan mine,the reason for the increase of gas emission was obtained through the analysis on gas permeability mechanism of coal floor rocks and the calculation of gas emission quantity from the adjacent seams at the working face.Due to the effect of mining on the coal floor at No.18205 working face,the fissure zone and pressure released zone formed in the coal rocks,and the permeability coefficient of coal rock increased a hundredfold,providing pore passages for gas emission from the underlying adjacent seams.The gas emission from No.9 underlying coal seam accounts for 11.4 % of total gas emission at No.18205 working face.Combined with theoretical analysis,calculation and mining conditions,the experiment of gas drainage was carried out in the floor gas drainage roadway.The results indicated that this method could effectively control the gas emission from coal floor with a result that the gas concentration of floor descended from 0.46% to 0.1%,the ratio of gas drainage increased 17%,and the ventilation effect was improved in the draft.