Study On The Characteristics Of Spontaneous Combustion In Goaf Of Coal And Its Prevention And Control Measures In Gas Abnormal Area Of Baodian Mine

Mine gas and spontaneous combustion of coal is the two major disasters in coal mine safety production.In recent years,China's coal mine mining depth increasing,abnormal gas emission phenomena of coal mining process.This results gas overrun and local gas accumulation in working face upper corner and return air lane.Reducing the working face advancing speed.Increase the risk of spontaneous combustion of residual coal in Goaf.In this paper,we take the 7309 upper working face of seventh mining area in Baodian coal mine as the research object.This paper has carried on the analysis and research of coal spontaneous combustion gas anomaly zone control technology through the theoretical analysis,experimental study,numerical simulation and field practice.The existing temperature programmed experimental device has some disadvantages,such as low speed of heating,temperature is difficult to control,uneven heating of coal,and gas tightness.So we build an integrated coal spontaneous combustion test device with integrated design,simple operation,small amount of oil.The amount of coal loading is 250 g,and the air supply is 7.4³9.9ml/min.Debugging the experimental device until high speed of heating,temperature is easy to control,and strong tightness when device can meet the requirement of experiment that the influence of gas on coal spontaneous combustion characteristics.According to the temperature programmed experimental results about coal samples of 7309 working face in Baodian coal mine under different particle size,coal critical temperature are 75?⁹0?,and dry temperature are 110?¹20?.And preferably CO gas and C₂H₄ gas as the main gas of coal spontaneous combustion prediction index.Take mixed sample as the sample on experiment that the influence of gas on coal spontaneous combustion characteristics.According to the experimental results,the gas take inhibitory action in coal spontaneous combustion process.So we should reduce the concentration index while using the CO and C₂H₄ gas as the prediction index of gas on coal spontaneous combustion.At the same time,the coal spontaneous combustion limit parameters were obtained according to the experimental results,which provided the theoretical basis for the "three zones" of spontaneous combustion in goaf.Through numerical simulation research on the 7309 working face goaf,we can get oxygen concentration field distribution,and the influence on goaf oxygen concentration field distribution under different surface wind speed and corner gas control measures.When the wind speed of the working face is increased or the corner gas control measures are increased,the oxidation of the goaf increases to the deep part of the goaf and the width increases,which increases the risk of coal spontaneous combustion in goaf.Were measured on 73 on the 09 working face of Baodian coal mine spontaneous combustion parameters were obtained,and the three zones of mined out area,determine the focus of prevention and control of spontaneous combustion in goaf area,the air inlet side of the oxidation temperature rise 50¹20m,return side oxidation temperature rise calculation of 20⁴0m working face advance rate for average daily limit 2.69m/d.According to the experimental results and numerical simulation results,combining with the actual situation of the mine,using fly ash grouting fire prevention technology,inorganic curing expansion filling technology,and colloid fire prevention technology in goaf to prevent spontaneous combustion.According to the monitoring data,during the whole exploitation,the corner gas is not overrun,and the spontaneous combustion of coal in goaf is not realized.