Abstract: In order to effectively prevent and control coal spontaneous combustion in goafs, studies were carried out with 014N1^-1fully mechanized mining face of Ruian Mine as an object to acquire the data of oxygen concentration and air leakage speed under the condition where the actual air supply volume of the working face was 1 150 m³/min. According to the "three zones" division standard of coal spontaneous combustion in goafs and numerical simulation method, the dynamic change of spontaneous combustion zones under different supply volumes of air was studied by using Comsol software, then the scope of spontaneous combustion zone was determined, and the fitting curve of the mining face's air supply volumes and width of the zone was obtained. Finally, the fire prevention and extinguishing technology, which combined air flow separation wall with nitrogen injection, was put forward. The results show that as the air supply volume raises, the boundary of the spontaneous combustion zone expands to the deep section of goafs and its width also increases gradually, and the air supply of working faces should be lower than 1 500 m³/min in view of the current mining conditions and heading speed. It is also found that the technology which features a combination of air flow separation wall and nitrogen injection can shrink the spontaneous combustion zone to a width of 24.6 m, and it proves to have better effect in fire prevention and extinguishment.

Key words: goaf, coal spontaneous combustion, air supply volume, dynamic simulation, fire prevention and extinguishing technology