Spontaneous Combustion Regularity And Prevention Technology Of Fully Mechanized Caving Mining On The Lower Slice In Wangwa No.2 Mine

Coal spontaneous combustion is an important disaster in China's coal mines,not only caused a lot of resource losses,but also a serious threat to the safety of coal production.The coal mining method is one of the main factors that affect the spontaneous combustion of coal.The lower layer will re-expose the influence of the air leakage on the coal seam,which will lead to the re-oxidation of the upper layer coal and increase the risk of spontaneous combustion of coal on the lower slice.When fully mechanized caving mining is adopted,the discharge rate of top coal is low in two lanes,and there is a large amount of residual coal remaining in the two goaf,which is the most spontaneous combustion area of coal.The 5#thick coal seam 03 section is slicing mining in Wangwa No.2 Mine.The upper layer adopts fully mechanized coal mining.The lower slice adopts fully mechanized caving mining.Under full mechanized caving mining on the lower slice,goaf and layered goaf are connected,the roadway roof fracture zone and multiple layered goaf through layered floating coal resulting in pre-oxidation oxidation occurred again,increasing the probability of spontaneous combustion of coal.Under full mechanized caving mining,two meters within the scope of the top coal recovery rate is low,leaving a lot of residual coal,prone to spontaneous combustion of coal.Therefore,it is very important to study the coal spontaneous combustion characteristics and control technology in the lower stratified mining of Wangwa No.2 Mine.In this paper,the 115032 fully mechanized caving face as the research object in Wangwa No.2 Mine.Firstly,combined with the theory,the characteristics of spontaneous combustion of coal in fully mechanized top coal caving mining are analyzed.Secondly,application of industry analysis,surface structure analysis,temperature programmed experiments and large-scale coal spontaneous combustion experiment on 115032 fully mechanized caving face in the upper corner of mixed coal experiment,analysis of mixed coal volatile,large specific surface area and the proportion of micropores and mesopores,the critical temperature is 50?60?,the drying temperature is 110?120?,the coal temperature of C2H4 appears to be 70-90?,the coal temperature of C2H6 appears to be 80?90 ?,and the spontaneous combustion period is 22 days.Thirdly,the distribution of floating coal thickness,oxygen concentration and air leakage intensity in the goaf of 115032 fully mechanized caving face and the 215021 fully mechanized caving face are carried out.Combined with the limit parameters of coal spontaneous combustion obtained from the experiment,it is concluded that the oxidation zone of the 115032 fully mechanized top coal caving face on the lower slice is more than 215021,closer to the working face,and the depth of the suffocation zone is not very different.Finally,combined with the experiment and the coal spontaneous combustion danger zone in goaf of 115032 fully mechanized caving coal on the lower slice,the application of nitrogen injection,grouting and polymer colloid comprehensive fire prevention to control the hidden danger of coal spontaneous combustion in the broken roof and open-off cuts,and prevent the spontaneous combustion of coal during stoping,temporary stopping mining and recovery,It has been proved that the comprehensive fire prevention technology has a good effect on the prevention and control of coal spontaneous combustion in 115032 fully mechanized caving coal on the lower slice.The results of this paper provide theoretical,experimental and technical reference for the prevention and control of coal spontaneous combustion in the similar working face.