Detection and location of places of spontaneous combustion of coal in mines due to gas anomalies on the earth’s surfaceVyacheslav Portola, Alyona Bobrovnikova, Georgii Shirokolobov and Dmitiy PaleevE3S Web Conf., 174 (2020) 01061DOI: https://doi.org/10.1051/e3sconf/202017401061