复杂地质条件下自燃煤层切顶留巷防灭火技术研究

Research on Roof Cutting and Retaining Roadway Fire Prevention and Extinguishing Technology in Spontaneous Combustion Coal Seams under Complex Geological Conditions

针对切顶开采条件下,工作面地质条件复杂,采空区遗煤多,采空区自然发火风险将急剧增加,存在采空区漏风量大、漏风范围广等问题,本文以360804综采工作面切顶开采为研究背景,采取以连续注氮为主,辅以每3 d预防性灌浆一次、每周预防性注液态CO_(2)一次的综合防灭火措施。结果表明:切顶留巷时,由于柔模墙漏风,采空区氧化带有所增加,通过采取连续注氮、预防性灌浆、灌注液态CO_(2)等措施,有效减少了采空区自然发火风险;庚19、庚20煤层自然发火标志性气体是以C_(2)H_(4)和CO为主,C_(2)H_(2)为辅,应用防漏风和注氮防灭火措施对采空区遗煤氧化有较强限制作用;应用采空区防漏风和间歇性注氮措施后,在留巷期间未检测到自然发火指标气体,实现自燃煤层切顶卸压沿空留巷安全开采。

In view of the problems that under the condition of roof cutting mining,the geological conditions of the working face are complex,and there is a lot of coal left in the goaf,the risk of spontaneous combustion in the goaf will sharply increase,large air leakage rate and wide air leakage range in the goaf and so on.This article takes the roof cutting mining of the 360804 fully mechanized working face as the research background,and adopts a comprehensive fire prevention and extinguishing measure mainly consisting of continuous nitrogen injection,supplemented by preventive grouting every 3 days,and preventive injection of liquid CO_(2) once a week.The results show that when cutting the roof and retaining the roadway,due to air leakage from the flexible formwork wall,the oxidation zone in the goaf increases.By adopting measures such as continuous nitrogen injection,preventive grouting,and liquid CO_(2) injection,the risk of spontaneous combustion in the goaf is effectively reduced;The iconic gases of spontaneous combustion in the Geng19 and Geng20 coal seams are mainly C_(2)H_(4) and CO,supplemented by C_(2)H_(2).The application of anti air leakage and nitrogen injection fire prevention and extinguishing measures has a strong limiting effect on the oxidation of left coal in the goaf;After applying measures to prevent air leakage and intermittent nitrogen injection in the goaf,no spontaneous combustion indicator gas is detected during the period of retaining the roadway,achieving safe mining of retaining the roadway along the goaf by roof cutting and pressure relief in the spontaneous combustion coal seam.