Study On The Risk Assessment And Prevention Measures Of Compound Disaster In Goaf Of Yangmei No.1 Coal Mine

With the continuous increase of mining depth,a large number of coal is lost in the goaf during the mining process,which makes the goaf become the main place of coal spontaneous combustion disaster.It is of great significance for the prevention and control of complex disasters to accurately distinguish and divide the risk areas of complex disasters in goaf and to establish the corresponding risk assessment system of complex disasters in goaf.Based on the research background of 81303 fully mechanized top coal caving face in Yangmei No.1 coal mine,a risk assessment system of composite disaster in the goaf of the fully mechanized top coal caving face is established by means of laboratory experiment,field observation and numerical simulation,and the risk of composite disaster in the goaf of 81303 fully mechanized top coal caving face is analyzed and evaluated.The main conclusions are as follows:1)The gas products and their active groups in the process of spontaneous combustion and oxidation of coal in dry air were obtained by means of temperature programmed furnace and ESR spectrometer.2)Through the pipe sampling in the goaf,the gas concentration of each component in the gas sample is analyzed by the gas chromatograph,and the gas concentration distribution law of each measuring point in the goaf is obtained by the regression analysis.The "three zones" of spontaneous combustion,the gas explosion area and the composite disaster area of gas and coal spontaneous combustion in the goaf of 81303 fully mechanized caving face are scientifically divided.3)Because the small coal pillar is only 8 meters between the goaf of 81303 fully mechanized caving face and the adjacent old goaf,the old goaf poses a double threat of gas and spontaneous combustion to the mining of 81303 fully mechanized caving face,therefore,an observation system is established on the small coal pillar,and the change rule of gas concentration and temperature in the old goaf during the mining process of 81303 fully mechanized caving face is analyzed.4)Through numerical simulation,the evolution rule of gas and spontaneous combustion risk of the old goaf to the goaf of 81303 fully mechanized top coal caving face is obtained under the condition that the change of air supply volume and permeability of small coal pillar are affected by mining.5)In this paper,the quantitative theory III is introduced into the evaluation of gas and spontaneous combustion risk in goaf.Taking the thickness of the remaining coal in the goaf and the thickness of the coal pillars in the adjacent goaf as the qualitative evaluation indexes,taking the oxygen concentration in the complex disaster area,the gas concentration in the complex disaster area,the air leakage,the daily average advance distance of the working face,the oxygen concentration in the adjacent old goaf and the temperature in the adjacent old goaf as the quantitative indexes,the risk evaluation model of the complex disaster area in the goaf is established In this paper,the risk of goaf and its isolated small pillar composite disaster area in 81303 fully mechanized caving face of Yangmei No.6)The comprehensive prevention and control technology system of gas and coal spontaneous combustion in 81303 working face is established,including the natural prevention and control system and gas control measures.The prevention and control system of coal spontaneous combustion is divided into the optimization scheme of pressure equalizing system,the establishment of dynamic real-time detection system and safety guarantee measures for small coal pillar and adjacent old goaf,the acceleration of working face advancement speed and the reasonable air distribution of working face The control measures mainly include air exhaust gas and inorganic firefighting materials plugging and reinforcing coal pillars.Through the test of the effect of injecting inorganic fire-fighting materials into the adjacent small coal pillars,the original and new cracks in the small coal pillars caused by the mining activities and the impact of ground pressure are effectively blocked,and the spontaneous combustion of the remaining coal in the adjacent old goaf is restrained,and the effect is good.The paper has 44 pictures,20 tables and 80 references.