Numerical Simulation on Distribution of "Three zones" in Gob of Full-mechanized Caving Face before and after Being Injected Nitrogen

Distribution and variation of three zones in gob is the basis of predicting spontaneous in mined-out area.In this paper,we firstly established the porous medium mode of goaf using the fluid software combining the practical case of north of 703 fully mechanized caving face of Daxing mine,Obtained changes in the scope of three zones in gob by numerical simulation of oxygen concentration before and after injecting nitrogen,referring the spontaneous combustion of Daxing Coal Mine,identified the minimum advancing,which ensured that it didn't occur spontaneous combustion in the face.Accordingly,we can predict the spontaneous combustion danger in gob of mined-out area.