Research And Application Of Natural Fire Prevention Technology In Xinwei Coal Mine

Mine fire accident is one of the factors that threaten the safety production of coal mine enterprises.Statistics show that more than half of coal mines in China are threatened by fire accidents.Every year,a large number of coal will be burned in mine fire accidents,which will cause resource damage and property damage.In addition,the toxic gas produced by coal spontaneous combustion will threaten the safety of underground workers.When mining close seam group,there will be more air leakage channels in the upper and lower goaf disturbed by mining.At the same time,a large number of coal remains in the goaf,which increases the risk of coal spontaneous combustion.In this paper,the coal seam of Xinwei coal mine in South Sichuan is studied.The methods of theoretical analysis,experimental research,numerical simulation and field application are used.The main achievements are as follows:Based on the field data,the risk of spontaneous combustion in the close coal seam of Xinwei coal mine is evaluated.Through the identification test of spontaneous combustion tendency of coal,it is determined that 7 and 8 coal seams are class II spontaneous combustion coal seams with high sulfur content.The process of spontaneous combustion and oxidation of coal was simulated by temperature programmed test platform,and the index gases of CO and C₂H₆ were selected to predict the spontaneous combustion of coal.The parameters of the minimum thickness,the lower limit oxygen concentration and the upper limit air leakage intensity are obtained.The physical model of goaf is established by FLUENT software,and the numerical simulation is done.The air leakage parameters and gas components migration rule in goaf of close seam are simulated,and the distribution of three spontaneous combustion zones is determined.The oxidation zone is located in the area of 40m-105m away from the working face.The measurement scheme of the three zones of spontaneous combustion in goaf is designed,and the distribution area of the three zones is measured.The numerical simulation results are consistent with the measured data to further determine the goaf areas prone to spontaneous combustion.According to the mining situation of Xinwei coal mine and the existing technical conditions,a comprehensive fire prevention and extinguishing technical scheme of coal seam grouting and goaf carbon dioxide injection is designed,and the fire source is successfully eliminated.