Determination of the Zone with a Particularly High Risk of Endogenous Fires in the Goaves of a Longwall with Caving

During ventilation of longwalls, part of the air stream migrates into goaves with caving. In the case where these goaves contain coal susceptible to spontaneous combustion, such air flow through the goaves may lead to the formation of favourable conditions for coal oxidation and, subsequently, for its self-heating and spontaneous combustion. The ensuing endogenous fire may constitute a serious hazard to the mining crew and underground operations. The article presents the results of a numerical analysis of air stream flowing through the goaves of a longwall with caving ventilated with the U-type system from the exploitation field borders. The purpose of the analysis was to demarcate the zone with a particularly high risk of endogenous fires within the goaves. The hazardous values of air flow speed and oxygen concentration in the goaves, responsible for the commencement of low-temperature coal oxidation, were determined for specific mining and geological conditions