Abstract: Treatment of coal spontaneous combustion is the key point to mine production. On the basis of analysis of distribution of support pressure and air flow state of coal mine goaf, distribution law of air flow rate in middle of goaf is derived. Finally width of the combustion zone under special condition was confirmed using numerical method. Analysis shows that combustion width changes little with the distance to mining face when combustion area closes to mining area. The longer the mining face, combustion area closer mining face, combustion width basically unchanged. The smaller the change rate of support pressure in goaf, distance of combustion area to mining area increases with the increase of width.

Key words: Goaf, Combustion area, Air velocity