Experimental Study And Field Application Of A New High-water Inorganic Fire-extinguishing Material To Inhibit Spontaneous Combustion Of Coal

Mine fire is an important form that threatens the safe production of coal mines.Small coal pillars are typical fractured coal-bearing rock masses.During the mining process of working face,the strength of coal rock mass is greatly reduced when it is repeatedly subjected to mining stress and concentrated stress.The permeability of the coal and rock mass is geometrically increased,which leads to a multiplication of the spontaneous combustion of the residual coal in the adjacent goaf,which seriously threatens the safe production of the working face.Due to the limitations of the current single fire protection technology,it is impossible to meet the fire prevention requirements in the underground mining process to the greatest extent.Therefore,on the basis of coal spontaneous combustion mechanism and traditional fire-fighting technology,it is of great significance to study a kind of fire-extinguishing materials with both blocking and resisting properties for coal spontaneous combustion prevention.In this paper,the prevention and control effects of new high-water inorganic fireextinguishing materials in the process of coal oxidation and spontaneous combustion were studied by the combination of experimental research and field application.Firstly,using MgCl2 as a comparison,the influence of new high-water inorganic fire-extinguishing materials on the main reactive functional groups in coal oxidation process was investigated by means of Fourier transform infrared spectrometer.The results show that the new high-water inorganic fire-extinguishing material can better inhibit aliphatic hydrocarbons(methyl-CH3,methylene-CH2),aromatic hydrocarbonCH,hydroxyl-OH and carboxyl-COOH than MgCl2 in the whole oxidation temperature rising process.The reactive group participates in the oxidation reaction,reduces the reaction consumption,and accordingly reduces the formation of secondary functional groups such as carbonyl C=O,thereby slowing the rate of spontaneous combustion of coal.Secondly,the 81303 working face of Yangmei No.1 Mine is used as the research object of the field application.Firstly,a set of small coal pillars suitable for the 81303 working face of Yangmei No.1 Mine and the monitoring system of the adjacent goaf are established,so that the adjacent goaf can be obtained at any time.Data on gas and temperature in the zone.Then according to the obtained data and analysis,the hidden dangers and danger distribution of spontaneous combustion in adjacent goafs are obtained,and a new high-water inorganic fire-extinguishing material grouting system suitable for this working face can be established.Finally,the effect of the new high-water inorganic fire-extinguishing material on the small coal pillar and the spontaneous combustion hazard in the adjacent goaf is analyzed.The results show that the new high-water inorganic fire-extinguishing material has less added amount and simple process,which better solves the small coal pillar.The problem of air leakage and the hidden danger of spontaneous combustion of coal in the adjacent goaf is a good sealing and fire-extinguishing material,which has great promotion and application value.