Research On The Law Of Air Leakage In Goaf Of Gob-side Entry Retaining With Y-type Ventilation System On Feng Huangshan Coal

Mine fire and gas explosition is prominent disasters of coal mine in Chine, which seriously affects the normal underground exploitation and the lives safety of workers. Work-oriented goaf leakage, on the one hand, which creats a necessary condition for spontaneous combustion of coal in gobs because of large quantities of oxygen; on the other hand, the return air to the face in the goaf, which causes the goaf gas emission, resulting in the exploitation working face corner gas accumulationcreate the conditions for the gas explosion.It improves the recovery rate of coal resources, alleviates the problem of convergence of face extraction on No.154307workface firstly using Y-type ventilation and retained roadway along goaf in Fenghuangshan Coal. Long-term monitoring, combined with mines154307mechanized mining goaf gas instantaneous release of SF6technology for the determination of the goaf flow field and leakage conditions, the study of Gob law.Main contents and conclusions are as follows:1. Analysis of the advantages and disadvantages of the relatively face ventilation systems; Y-shaped ventilation air leakage along the goaf with technical features and the goaf influencing factors.2. From the long-trem monitoring to the Fenghuangshan Mine154307face along the roadway retaining wall goal and working gas emission obtained:(1) throughout the recovery period, only1#and5#measuring points in the face, respectively, advancing about450m and650m, the oxygen concentration to attain significant downward trend, but still high, the rest of the oxygen concentration in about20%, it can see in the recovery period the goaf there has been a serious air leakage, air leakage distance of up to more than500~600m;(2) with the face to promote the increase of the distance, gob methane concentration gradually increased; away from the face600m range, the concentration of0.3%, and finally maintained at about1.4%;(3) the process of mining face, gas which is on the corner is basically in between0.2%to0.4%.3. Through the instantaneous release of SF6technology, determination of the Fenghuangshan Mine154307goaf leakage, romantic flow state of the field test goaf. Analysis of all sampling points collected to the distance of the peak concentration of SF6gas and the face and the goaf air leakage change the relationship between wind speed and the sampling distance of dot pitch face drawn each sampling point of collection to the peak concentration of SF6gas and face expression from the curvetype:first:y1=53.171e-0089x,second: y2=43.48e-00635x;Of Gob wind speed and distance curve sampling dot pitch face expression:the first:y1=0.0644-01753xsecond:y2=0.0996e-0.1729x。4. Fluent software simulation of goaf flow and goaf oxygen distribution, the simulation results and on-site monitoring and testing resulting in higher consistency. Provide the basis for future research goaf "zone" and the development of the release of fire-fighting measures.