Theory analysis on spontaneous combustion zone width in the middle of goaf

It is very important for the defeating and extinguishing fire in mine to the spontaneous combustion zone. Firstly, distributing condition of abutment pressure and air flowing state in goaf is analyzed by author; Then, theory formula of airflow velocity in the middle of goaf is deduced; Finally, the width of spontaneous combustion zone under several conditions is obtained by making use of numerical computation. The result of theory analysis indicates that: the air pressure difference is small, and the distance from spontaneous combustion zone to working face is closer, and its width reduces slightly; the length of working face is longer, and the distance from spontaneous combustion zone to working face is closer, and its width doesn’t change basically; the change velocity of abutment pressure in goaf is more slow, and the distance from spontaneous combustion zone to working face is more far away with its width increase.