近距离煤层群采空区自然发火指标及防控技术

    Prevention and control technology and goaf spontaneous combustion index in distance coal seams

    • 摘要: 为研究近距离煤层群自然发火规律,以神东矿区补连塔煤矿22煤三盘区工作面为例,采集补连塔煤矿22煤层煤样,筛选3种粒径煤样进行程序升温试验,分析试验中煤自燃生成的各气体体积分数、φ(C2H6)/φ(CH4)、φ(C2H4)/φ(CH4)及格雷哈姆系数R1(第一火灾系数)、R2(第二火灾系数)、R3(第三火灾系数)值与煤样温度变化关系,根据标志气体优选原则,选定CO气体体积分数和R2值为补连塔煤矿自燃预测预报的主要指标,C2H4、C2H6和R1值为辅助指标,补连塔煤矿煤样自燃临界温度60~75 ℃,干裂温度100~120 ℃;结合矿井煤层埋藏浅、层间距小、煤层易自燃的赋存特性,并考虑矿井工作面通风系统、工作面采掘部署情况,综合分析近距离采空区自然发火影响因素。结果表明:22煤层采空区运输巷、回风巷、开切眼、终采线及上覆采空区遗留煤柱为近距离采空区易自燃区域,采取地面钻孔对12煤层煤柱区域注浆、固定注浆站对22煤层采空区注浆,上下煤层采空区注氮惰化及超前布置工作面均压应急系统的综合防控措施,保障工作面安全回采,进一步完善矿井火灾预警及综合防控体系。

       

      Abstract: In order to study the spontaneous combustion law of close distance easy spontaneous combustion coal seams, taking the mining face of Bulianta Mine No.22 coal seam 3# panel as an example, collected No.22 coal seam samples of Bulianta Mine, three particle size coal samples were selected for programmed temperature rise experiment, the paper analyzed the relationship between the gas concentration generated by coal spontaneous combustion, φ(C2H6)/φ(CH4), φ(C2H4)/φ(CH4), numerical values of R1, R2, R3 and the temperature changes of the coal samples in the experiment. According to the principle of index gases optimization, the gas concentration of CO and numerical value of R2 were selected as the main indexes for predicting and forecasting spontaneous combustion of Bulianta Mine, the gas concentration of C2H4, C2H6 and numerical value of R1 were selected as auxiliary index, the spontaneous combustion critical temperature and dry cracking temperature of Bulianta Mine samples were 60 ℃ to 75 ℃ and 100 ℃ to 120 ℃. Combining with the occurrence features of shallow depth, close distance and easy spontaneous combustion of coal seam, considering the ventilation system in mining face and the condition of mining deployment, by the use of the programmed temperature rise experiment results and theoretical research, the paper comprehensive analyzed the influence factors of spontaneous combustion of close distance goaf. The results showed that the haulage gate, air return way, starting cut and stopping line of the No.22 coal seam goaf, and the remaining coal pillar of overlying goaf were areas prone to spontaneous combustion; comprehensive prevention and control measures such as ground drilling for grouting in coal pillar area of the No.12 coal seam, fixed grouting station for grouting in goaf of the No.22 coal seam, nitrogen injection in goaf of upper and lower coal seams and nitrogen inerting and advance arrangement of working face pressure equalization emergency system are adopted to ensure safe mining of working face and further improve the mine fire warning and comprehensive prevention and control system.

       

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