Research On Gas Prevention And Control Technology In Fully Mechanized Caving Face

Casualties and equipment damage caused by gas disaster accounted for a large proportion in all coal mine disasters. Gas disaster can result in the stagnation of production, and bring huge economic losses. Preventing the occurrence of gas disasters has very important sense to normal and safety production of coal mine.This paper studies the gas exceeding problem of12220fully mechanized caving working faces in GenCun mine2-3coal. It is concluded that the gas in12220working face is derived from the following aspects: the coal wall, falling coal, and mined-out area. It is showed that gas emission in mined-out area accounts for69.9%of the total gas emission volume through calculation. So it is particularly important to solve the gas problem in the mined-out area. According to the characteristics of the gas seeping and diffusing in mined-out, gas overrun problems on the working face are governed in several different governance ways.FLUENT software is used for numerical simulation of this problem, then gas distribution in gob will be present in intuitive and simple way by comparing the figures of simulation results, it also provides basis for the governance of gas overrun problem in this working face for the staff. Numerical simulations are done to these three kinds of prevention and control of gas technology by ventilating of U shaped ventilation, outside fault gas tail roadway and toward high pumping alley. Comparing the results, the following results are obtained.When the wind speed of the working face entrance is3.5m/s for fixed value, the gas concentration in the return airway and the upper corner of u-shaped ventilation is about1.8%and4.15%respectively, more than the prescribed level. When governed with the help of outside fault gas tail roadway, the gas concentration on the upper corner of the working face is lower than before obviously according to the simulation results, and at about0.95%, but it’s too close to the safe upper limit of1%, and the gas concentration in tail is as high as8.2%, which is not in conformity with the relevant provisions. When using toward high pumping alley, the gas concentration is about0.89%in it, and the gas concentration in the return airway and the upper corner is about1.8%and4.15%respectively. So it can solve the gas overrun problem of12220working face in GengCun coal mine effectively, and provide a reliable guarantee for the safety, normal and orderly production of the mine.