Meikuang Anquan (Sep 2022)
Early warning and control methods of coal spontaneous combustion in close distance coal seams in outburst mines
Abstract
The coal seam group in the outburst mine has the characteristics of mutual influence in the mining process, the goaf is connected, there are many air leakage places, and the fire prevention work is difficult. In order to accurately predict the coal spontaneous combustion process of the coal seam group near outburst mines, taking Guizhou Fa’er Coal Mine as an example, the variation law of each gas during the coal oxidation process was analyzed through the coal spontaneous combustion temperature programmed experiment, the comprehensive prediction indicators of the coal self -combustion single index gas and the marked gas ratio were determined, and the coal spontaneous combustion monitoring and early warning system and the field layout were proposed. The results show that the critical temperature range of each coal seam in Fa’er Coal Mine is 70-80 ℃, and the dry cracking temperature range is 130-140 ℃. Combined with the oxygen consumption, the occurrence temperature and change law of CO and C2H4, the priority order of spontaneous combustion oxidation of different coal seams in Fa’er Coal Mine is: 1# coal>3# coal>5-2# coal>5-3# coal>10# coal>7# coal. According to the experimental results and field data, six gas indexes(CO, O2, C2H4, ?渍(CO)/?渍(CO2), ?渍(CO2)/?渍(O2), ?渍(CO)/?渍(O2)) of coal spontaneous combustion temperature and the temperature range and gas index critical value of graded early warning were determined, realizing the four grades early warning of coal spontaneous combustion. Finally, a grading prevention and control method for coal spontaneous combustion is proposed for outburst coal seam groups, such as “strengthening coal spontaneous combustion prediction and forecasting, nitrogen injection to prevent and extinguish fires, dynamic advancing, air leakage plugging, or gel/polymer colloid injection”, which effectively solves the problem of early warning and control of coal spontaneous combustion in coal seam groups in outburst mines.
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