Abstract: To explore the dynamic variation rule of the width of spontaneous combustion oxidation zone in goaf and the spontaneous combustion period in the process of mining,the 014N^-1₁,fully mechanized caving face in Ruian was taken as an object of study,a COMSOL Multiphysics dynamic numerical simulation model was built,based on deformation geometry and other physical-chemical fields theories.According to the model,the numerical simulation research on the spontaneous combustion in goaf was carried out.The results show that the greater the quantity of wind and the lower the mining velocity,the longer the time,the oxidation zone takes to appear for the first time,will be,and the shorter the spontaneous combustion period will be,that there is a S-shaped relationship between the maximum width of oxidation zone and time,that at the initial stage of mining,the oxidation zone width decreases with the increase of the quantity of wind.At the stable mining phase,the greater the quantity of wind,the wider the oxidation zone width will be,and that the faster the mining velocity,the lower the ratio of the maximum width of oxidation zone to the mining velocity will be,and the smaller the risk of spontaneous combustion will be.

Key words: goaf, spontaneous combustion, oxidation zone, spontaneous combustion period, dynamic instability