Research On The Prevention And Control Technology Of Coal Spontaneous Combustion In The Mining Area Of High Ground Temperature Comprehensive Release Working Face

As a major coal consuming country,the development of deep coal resources has become urgent along with the increasing depletion of shallow coal resources in China.However,due to the deepening of mining depth,the ground temperature of the mined coal seam is gradually increasing,which increases the possibility of natural fire in the mining area and poses a threat to the safety of mining.The mining depth of Xinhu coal mine in Bozhou,Anhui Province is-927m,and the ground temperature reaches 42.0°C.The high ground temperature environment has affected the safe mining of 8 coal seams,so it is necessary to carry out research on the characteristics of coal spontaneous combustion and coal spontaneous combustion prevention technology for the high ground temperature environment.The low-temperature oxidation process of coal in the 8-seam at different starting temperatures was simulated by programmed warming to reveal the influence of different ground temperature environments on the low-temperature oxidation of coal.The release of CO and C₂H₄ concentration increases with the increase of the starting oxidation temperature at the same coal temperature（starting temperature is 50℃>40℃>30℃）;the parameters of coal spontaneous combustion such as oxygen consumption rate,CO,CO₂ production rate,exothermic intensity,activation energy,etc.also show a gradual increase with the increase of the starting oxidation temperature at the same coal temperature（starting temperature is 50℃>40℃>30℃）.It is clarified that the ground temperature has a certain influence on the low temperature oxidation characteristics of coal.When the absolute CO generation and R₂are used as the prediction index of coal spontaneous combustion in high ground temperature coal seam,the critical alarm value should be increased when the ground temperature increases;the critical value should be set according to the ground temperature of the coal sample as the starting temperature for the experiment.Combining with the actual situation of 818 working face in Xinhu coal mine,the key factors of natural fire in the mining area of high ground temperature general release working face are analyzed.That is,the high ground temperature environment,the increase of coal left in the mining area due to the release of top coal mining,and the complex air leakage conditions in the mining area due to gas extraction.Through the actual measurement of the temperature and gas concentration changes in the air mining area,combined with the index of spontaneous combustion hazard zone division in the air mining area,the range of spontaneous combustion hazard zone in the 818 working face was determined:32-96m in the inlet side and 24-94m in the return side,and the minimum safe advance speed was also calculated.Numerical simulation of the impact of surface well gas extraction on the range of spontaneous combustion danger zone in the mining area of 818 working face,the impact of surface well extraction on the range of spontaneous combustion danger zone in the return wind side of the mining area is especially obvious,increasing the possibility of natural fire in the mining area.The actual situation of the mining area of the 818 working face proposed a method of preventing and controlling the spontaneous combustion of coal in the mining area by integrating"online monitoring,air leakage control,inerting and oxygen reduction,heat absorption and temperature reduction",and established a system of preventing and controlling the spontaneous combustion of coal in the mining area of the high ground temperature general release working face.The actual application effect of Xinhu coal mine 818 comprehensive release working face shows that the coal spontaneous combustion prevention and control system has effectively suppressed the spontaneous combustion of coal left in the high ground temperature mining area.Figure 48 Table 13 Reference 94...