Study on the critical value of spontaneous combustion mark gas in 4-1 coal seam in Shuangma Coal Mine

The coal seam of main mining in Shuangma Coal Mine is characterized by short spontaneous ignition period and easy to be spontaneous. In order to determine the reasonable prediction index of coal spontaneous combustion, taking 4-1 coal seam of main mining as the research object, the experimental analysis, field test and statistical analysis were used to study the critical value of spontaneous combustion mark gas. According to the oxidation experiment and field observation of coal sample in 4-1 coal seam, the spontaneous combustion mark gas in 4-1 coal seam was optimized, at the same time, the safety management value of CO volume fraction and the critical value of spontaneous combustion in the upper corner of fully mechanized mining face were determined. On this basis, graded early warning response and fire prevention technology management system of coal seam spontaneous combustion were established. The results show that CO, C₂H₄, C₂H₂, C₃H₈ are the mark gas of spontaneous combustion in 4-1 coal seam of Shuangma Coal Mine; the safety management value of CO volume fraction in the upper corner of Ⅰ0104₁05 working face is 60×10^-6, and the critical value of spontaneous combustion is 430×10^-6; a 4-level warning and response system including blue (Ⅰ), yellow (Ⅱ), orange (Ⅲ), red (Ⅳ) of spontaneous combustion is established.