The factors that have the greatest influence on the probability of endogenous fires during the mining of thick steep formations of the Prokopyevsk-Kiselevskoye field in Kuzbass have been determined. The study of stress-strain state of sublevel coal pillars with the use of continuum mechanics approaches was carried out. It is concluded that the sublevel coal pillar left nowadays at the mines of OOO MC Prokopyevskugol is destroyed and does not fulfill isolating functions, being in the end the main or indirect source of fire hazard. The method of mining of thick steep seams prone to spontaneous combustion is proposed, which excludes sublevel coal seals and provides reliable isolation of the mined area.
