Study On Comprehensive Control Technology Of Gas Based On Gob-side Entry Retaining In Xin Yuan Coal Mine

Based on gob-side entry retaining with high water material for roadside packing in Xinyuan coal mine 3107 working face,using the method of theoretical analysis,numerical calculation and field test,this paper researched the development and evolution law of goaf fissure along with working face advancing.Three-dimensional numerical model is established.The distribution law of gas concentration in goaf is revealed,and the technical scheme of comprehensive gas control is put forward in the 3107 working face.Field practice has obtained the good economic benefit and safety effect.The results achieved are as follows:(1)This paper studies the maximum height of the caving zone and the fissure zone of the goaf by using the empirical formula method,the uphole water injection method and the numerical simulation method.It is determined that the range of the caving zone is 0-10 m,the fracture zone is 10-36 m and the porosity in each zone.(2)On the basis of the classical theory of rock pressure and the theory of O type circle,the failure characteristics of overlying strata of goaf are studied.Threedimensional numerical model is established.The distribution of gas concentration in goaf was obtained,which provided the basis for comprehensive gas control.(3)Through the method of theoretical analysis and numerical simulation,the gas control parameters of the horizontal boreholes,the ratio of Y type ventilation,the high level boreholes and the buried pipes of goaf are determined.Among them,the proportion of air distribution ratio of main and auxiliary air lane of Y type ventilation is 3.3:1.And main lane air volume is 2000m3/min,auxiliary lane air volume is 600m3/min.On the basis of the technical parameters of comprehensive gas control,the technical scheme of gas comprehensive treatment in 3107 working face is put forward,including the gas drainage scheme of pre-mining borehole,the gas drainage scheme of the high level borehole and the gas drainage scheme of the buried pipe in the goaf.The above research results have been applied in the 3107 working face of Xinyuan coal mine.Compared with the U+L ventilation system,the maximum gas concentration in the return airway is 0.4% after the Y type ventilation system is adopted.The maximum gas concentration is 0.56% in the gob-side entry retaining wall.The air distribution volume of working face is reduced from 3000m3/min to 2600m3/min.And achieved good economic benefit and safety production effect.It provided reference and basis for gas control technology under similar conditions.