Numerical Simulation and Division of Spontaneous Combustion "Three-Zone" in Low Gas Mine

The minimum monthly advancing degree which is beneficial to prevention and control on spontaneous combustion is identified by dividing spontaneous combustion "three-zone" of gob.At present,the division standard of gob spontaneous combustion "three-zone" has not been formed.According to practical situation of 0912 working face in Qipanjing coal mine,four measurement points are arranged along the gob.The new method of dividing spontaneous combustion "three-zone" of gob in low gas mine is determined by measuring the changing laws of gas components of gob.Fluent software is applied to simulate the spontaneous combustion "three-zone" of gob.The result shows that the cooling zone is less than 24 m,the spontaneous fire zone is from 24 m to 113 m,and the suffocation zone is more than 113 m.In order to take the residual coal of gob to the suffocation zone in the shortest spontaneous combustion period,the minimum monthly advancing degree should exceed 68 m.