Study On Spontaneous Combustion Characteristic And Preventive Technology In Deep Mining Of Coal Seam In Shaanxi And Inner Mongolia Area

Coal spontaneous combustion seriously threatens the safety of mine personnel and property.Once it happens,it will cause great waste of coal resources and serious environmental pollution.Shaanxi and Inner Mongolia have large reserves of coal resources,a large number of coal seams and a wide range of coal seam burial depth.The spontaneous combustion characteristics and regularity of coal seam change with different mining depth This article takes 106 fully mechanized caving face of A Coal Mine and 2201 fully mechanized mining face of B Coal Mine in Dongshcng Coalfield of Shaanxi-Mongolia area as the research object,the factors affecting spontaneous combustion in deep mining,the characteristics of spontaneous combustion in 2-2 coal seam and the dangerous zone of spontaneous combustion in coal seam are studied.A targeted technical system for preventing spontaneous combustion of coal seams is establishedThrough field investigation and theoretical analysis,it is found that the deep mining of coal seams in Shaanxi and Inner Mongolia area is mainly affected by the increase of in-situ stress,formation temperature and hydrogeological conditions,which shortens the spontaneous combustion period of coal,increases the spontaneous combustion point and fiurther increases the risk of spontaneous combustion of coal.Through coal spontaneous combustion experiment and temperature programmed experiment,the spontaneous combustion period of 2-2 coal is detemmined to be 30 days;the critical temperature of coal spontaneous combustion is 67.2 ?the dry cracking temperature is 116.5 ? and the fission temperature is 151?;the index gas production rate of coal sample is negatively correlated with coal particle size,and the oxygen consumption rate is negatively conrelated with coal particle size under the same reaction conditions;C2H4 can be used as the predictive index gas of coal spontaneous combustion in 2-2 coal seam.C2H6 can reflect the intensity of oxidation reaction of 2-2 coal at high temperature.The oxygen concentration field and air leakage in goaf of 106 fully mechanized caving face and 2201 fully mechanized mining face were obtained by field observation and Fluent numerical simulation.It is judged that the oxidation heating zone of 106 goaf is 30-180 m on the intake side,10?109 m on the return side and 6.8 m on the width.The oxidation heating zone of 2201 goaf is 47?180 m on the intake side,23?93 m on the return side and 6.2 m on the width.Under similar mining environment,106 fully mechanized caving face has larger spontaneous combustion danger area and closer to the working face than 2201 fully mechanized mining face.The dangerous areas of spontaneous combustion in 2-2 coal seam face include open-cut hole,stopping mining line,tail drainage lane,two-way position of goaf,roof along trough and two sides of coal wall.A technical system for preventing spontaneous combustion of coal in the whole process of mining is established by means of blocking air leakage,injecting colloid and injecting inert gas.Field application shows that the measures of plugging leakage and injecting inert gas can effectively prevent spontaneous combustion in coal seam.The research results have certain reference significance for the prevention of spontaneous combustion of coal seam in deep mining mines in Shaanxi and Inner Mongolia areas.