中国矿山工程

In order to reduce the gas emission in mined-out areas during 12408 working face stoping of Tunlan Mine, the surface L-shaped drilling is applied to gas extraction. Numerical simulation and theoretical calculation methods are used to determine the layout of the drills, the structure parameters of the drill holes are selected according to the site geological conditions, and the L-shaped drill hole gas extraction effect is analyzed in details. After site application, the gas concentration in upper corner and return air shaft of 12408 working face is reduced to less than 0.32% and 0.25% respectively, and the purpose of reducing gas emission in the mined-out area is achieved.