Numerical simulation study on spontaneous combustion hazard zone in upper goaf of shallow-buried short distance coal seams
When mining the lower coal seam in shallow and close distance coal seams,the surface fractures connect the old upper goaf through secondary development,resulting in an increase in air leakage in the goaf and a corresponding increase in the risk of spontane-ous combustion.Taking the space from 5-1 coal seam to the surface in Sujiagou Coal Mine as the research object,with the help of Flu-ent(a numerical simulation software),the impact of surface air leakage on spontaneous combustion dangerous zones of composite goaf,especially the upper 4-2 coal seam goaf,was studied.The research results show that the oxygen concentration in the goaf gradually de-creases as working face advances.The fractures connecting the upper goaf and surface have an impact on the distribution of oxidation zones in the goaf.According to the classification criteria for spontaneous combustion danger zones,combined with the distribution cloud map of the wind flow field and oxidation zone,the location and scope of spontaneous combustion danger zones are further determined.
shallow-buried and close distance coal seamsupper goafair leakagenumerical simulationdangerous zones of sponta-neous combustion
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