极近距离煤层重复采动影响下卸压瓦斯综合治理技术研究

Research on the comprehensive control technology of pressure relief gas under the influence of repeated mining in extremely close coal seams

针对极近距离煤层重复采动条件下工作面瓦斯涌出量大、回风隅角瓦斯易超限等问题,以彬长矿区大佛寺煤矿为工程背景,提出了“分区段”卸压瓦斯综合治理方法,并在40201综放工作面开展了工程实践。结果表明:40201综放工作面瓦斯涌出量大、回风隅角瓦斯易超限是由4号煤层顶板与4上号煤层采空区底板隔厚h不均、瓦斯抽采措施不合理等因素耦合造成的。应采取与h相对应的卸压瓦斯治理措施:h<8 m时,采取“上隅角迈步式埋管+风排瓦斯”的方式;8≤h<15 m时,采取“高位卸压钻孔+上隅角迈步式埋管+风排瓦斯”的方式;h≥15 m时,采取“高位定向钻孔+上隅角迈步式埋管+风排瓦斯”的方式。通过合理选择并实施卸压瓦斯抽采措施,有效降低了工作面瓦斯涌出量,回风隅角瓦斯未超限,确保了工作面的安全回采。

In response to the problems of large gas emission from the working face and disallowed gas concentration at the air return corner under the conditions of repeated mining in extremely close coal seams,taking Dafosi Coal Mine in Binchang mining area as the engineering background,a zonal-section comprehensive control method for pressure relief gas was proposed and successfully implemented in 40201 fully mechanized caving face.The results showed that the problems were caused by the the coupling influences of uneven thickness(h)between the roof of No.4 coal seam and the floor of No.4-upper coal seam goaf,the unreasonable gas drainage measures and other factors.On the basis of analysis,the control measures for pressure relief gas should be adopted corresponding to the thickness h:stepping pipe-burying at upper corner and gas drainage with wind when h<8 m;high-level pressure-relief drilling,stepping pipe-burying at upper corner,and gas drainage with wind when 8 m≤h<15 m;high-level directional drilling,stepping pipe-burying at upper corner,and gas drainage with wind when h≥15 m.The reasonable selection and implementation of pressure-relief gas drainage measures effectively reduced the gas emission from the working face,and controlled the disallowed gas concentration at the air return corner,ensured the safe recovery of the working face.