Research On Treatment Of Coal Seam Spontaneous Combustion Area Around Central Water Sump Of Jinbei Coal Mine

Coal spontaneous combustion is one of the main causes of mine fire,especially in the reorganized mine or the mine with small colliery around it.Due to the random excavation of the small coal mine and the improper maintenance in the later stage,the fire area of the small coal mine is complicated and the control of the fire area is more difficult.In order to efficiently solve the combustion problem in complex fire area of the central water sump in Jinbei coal mine,this paper adopts the comprehensive research method of theoretical analysis,experimental test and field practice,and puts forward a set of comprehensive treatment system for the small coal mine fire area.the main achievements and conclusions are as follows:In this paper,the characteristics of the fire area in the central water sump were comprehensively analyzed,and the interaction between the development of the fire area and the mining of 5103 working face was studied.According to the theoretical analysis and accident report investigation,the fire area of the central water sump in Jinbei coal mine has the characteristics of multiple fire sources,hidden fire source location,super-large three-dimensional fire area and spatial heterogeneity of the fire area.There was the risk of losing the original drainage capacity of the water sump and causing water damage accidents.Through the qualitative detection of the air leakage channel in the fire area by SF₆ tracer gas and the quantitative detection of the key air leakage area,the relationship between the fire area of the central water sump of the Jinbei coal mine and the 5103 working face is clarified,and the pressure energy between the fire area and the working face is drawn by point pressure measurement.It is found that the pressure energy of the return air roadway in the area is the lowest.The air flow flows to the return air roadway and does not converge to the working face.The normal mining of5103 working face can be ensured under the means of pressure equalization.In view of the fire characteristics of the central water sump fire area of the Jinbei coal mine,a comprehensive fire prevention and fire extinguishing system with the combination of surface and underground was constructed,a treatment scheme of shrinkage sealing and unsealing was formulated,and a comprehensive control system was formed.The ground fire prevention and fire extinguishing system mainly adopts surface pouring of large flow three-phase foam to extinguish the hidden fire source in the fire area.The underground grouting system constructs a total of 140 boreholes to the fire area through 8 drilling sites arranged in the return air inclined shaft,so that the injected colloid slurry and inert medium cover the fire area in all directions,and further control the fire area.Through the analysis of the gas sample data in the fire area,after treatment,the air temperature in the closed area was between 3-8?,which was similar to the daily temperature,the oxygen concentration was less than 5%,the carbon monoxide concentration was less than 10 ppm,and the water temperature was stable at 4-8?.The comprehensive verification index of unsealing in the fire area Tr and RT were less than 1,indicating that the fire area was stable and can be unsealed.It was proposed to unseal the 3^rd fire area first,and then unseal the whole fire area step by step according to the section A to F.The corresponding unsealing measures such as roadway dredging,roadway repair and grouting behind the wall have been formulated and taken.Finally,the fire zone was unsealed successfully,and the drainage capacity of the central sump was restored,thus ensuring the safe production of the coal mine.The treatment ideas and schemes of this paper can provide scientific guidance for the treatment of similar closed fire areas,and has important engineering practical significance.56 figures,10 tables and 75 references are contained in this thesis.