Abstract:
Taking Tunbao Coal Mine as an example, the reasons for spontaneous combustion signs during working face layout of spontaneous coal seams such as M9-10, M14, M15 were analyzed: after the mining of each coal face, the complex goaf is formed with the overlying goaf and the complex air leakage passage is formed between it and the surface; in addition, the working face is equipped with equipment and the tonnage of the bracket is large, and it is limited by the withdrawal process, and the bracket disassembly is difficult, resulting in a greatly extended withdrawal period of the working face; therefore, the heat storage condition of broken coal body in goaf is sufficient, and it exceeds the shortest firing period of coal seam, thus spontaneous combustion signs appear. In order to allow the working face to be withdrawn smoothly, according to the spontaneous combustion characteristics of the loose coal in the goaf during the removal, the fire extinguishing ideas of “full monitoring, pipe wind oxygen reduction, coal temperature control, and optimized process” were proposed. Comprehensive fire-fighting technical measures, such as pressure maintaining and oxygen control in goaf, nitrogen injection grouting combined with oxygen reducing and cooling, and targeted treatment of heating strips by high and low position drilling grouting, are adopted to ensure the safety of the working face when it is removed from the pedestal for a long time.