Study On Air Leakage Characteristics Along The Side Of Yingpanhao Fully Mechanized Caving Face And Pre-control Method Of Coal Spontaneous Combustion

The layout of coal seam mining,especially the way of leaving narrow coal pillars,is likely to cause air leakage along the side,increasing the risk of spontaneous combustion of coal.To study the air leakage characteristics along the side of the fully mechanized mining in Yingpanhao and the spontaneous combustion characteristics of coal adjacent to the gob along the side,the air leakage characteristics along the side when the roadway driving along next gob and the mining period of 2202 working face were studied.Based on the research of spontaneous combustion characteristics and index gas of Yingpanhao coal,the field observation of along gob side,and the numerical simulation research,the air leakage characteristics of the 2202 fully mechanized mining face of Yingpanhao are grasped and the coal spontaneous combustion prevention and control system are established.Temperature-programmed experiment and the secondary oxidation experiment were conducted by using different particle sizes coal of 2201 working face in Yingpanhao coal mine,and the critical temperature and cracking temperature of coal sample were determined.In addition,CO gas was used as main index gas to predicted coal spontaneous combustion and C2H4 gas was used as auxiliary coal spontaneous combustion predictive index gas.Comparing the oxygen consumption rate in the two oxidation process of coal sample,the following laws are obtained:before 90 ?,the oxidizing ability of secondary oxidation of coal sample is higher than that of primary oxidation of coal sample;after 90 ?,the oxidizing ability of secondary oxidation of coal sample is lower than that of primary oxidation of coal sample.The method of monitoring the gas in the gob along the side by construction drilling is used to determine the law of air leakage and coal spontaneous combustion in the adjacent gob.The results indicate that during the tunneling process along the gob,due to the ventilation method using local ventilation,the oxygen concentration in the coal pillar hole at the heading is higher than other holes.The oxygen volume fraction in the adjacent gob by coal pillar side is approximately 14.6%.Numerical simulation was used to study the oxygen concentration distribution law and air leakage law of the gob area of the 2202 working face of Yingpanhao.The adjacent gob of 2201 working face and the remaining coal pillars during the roadway driving along gob and the mining period were mastered.At the same time,the air leakage prevention and control and coal spontaneous combustion pre-control key areas in each mining stage were determined.At the same time,through the superposition of the velocity seepage field and the oxygen concentration field,it is determined the dangerous zones in the adjacent gob which are prone to spontaneous combustion during the 2202 fully mechanized mining face at the stages of the roadway driving along gob,the normal mining,and the working face advance to the stop line.The fire prevention technology system for adjacent gobs during the 2202 fully mechanized mining face along the gob,normal mining,temporary stop mining and support removing were established.The semi-section roadway shotcreting,long-term injection of nitrogen into adjacent gobs,and application of gel/polymer colloid in hazardous areas are used to pre-control the spontaneous combustion of coal in adjacent roadway and adjacent gob.A monitoring and early warning system for hazardous areas was established.Monitoring and early warning of air leakage in the gob along the side was realized.The paper has certain reference significance for the study of coal spontaneous combustion along the side of mine.