Study On Goaf Gas Flow Field Division In Mined-out Area

Gas accident of the sudden and uncertainty have serious influence on the coal minesafety production. After a survey, the goaf is the only area which can store largeamounts of free gas and gas hazard. It can be important theoretical and practicalsignificance by mastering the regional distribution of goaf. In this paper, we did a studyon goaf flow field and its distribution rule by using the theory of gas explosion theory,mine pressure theory, mine ventilation theory, gas flow diffusion theory in the basis ofHebei province science and technology support project named Prediction research ofcoal mine goaf gas explosion site and FenXi mining bureau major technical researchprojects named Coal spontaneous combustion gas iconic experimental study,Comprehensive control of coal working face gas combustion technology development.Using the gas as the tracer to simulated the laws of gas movements, concentrationgradient distributions and gas velocity in goaf on the self-made plat form. Trough thestudy and local control, goaf gas flow field can be divided into three areas named strongflow area, seepage area, non-seepage area. During the process of production, the Gasflow in the goaf can be affected by the caving and the subsidence of rock and otherforms of rock movement. This makes it possible to have a gas explosion. According tothe view of gas explosion was caused by the Spontaneous combustion of coal and thetheory of “U” shaped combustion zone, it can be sure that the gas explosion area in goafmainly existed in the caving zone of the two lanes which are located in the seepage areaof the goaf.Based on the experimental research and theoretical analysis, a measurement of thegas concentration in the goaf of the0401working face in the Masaaki ruentex FenxiCoal Limited had been carried out. The gas was gathered by deploying the gatheringpipe and tested by Gas Chromatograph, by this method, the gas composition and theirpercentage could be known exactly. The goaf was divided into three regions based theconcentration of CH4。According to the data of Hydrocarbon gas, the gas explosion areain the goaf had been located, and the gas flow model has also been revised. Thescientific and rationality of the research on the division of gas in goal has been proved, it provide a theoretical support to the prevention and control of the gas disasters andmake the gas extraction more efficiently.