On the issue of determining the main factors of gas hazard in coal mines of UkraineMykhailo Filatiev, Elvira Filatieva, Aleksandr Oleinichenko, Mihaela Toderas and Olga KuderinovaE3S Web Conf., 280 (2021) 08011DOI: https://doi.org/10.1051/e3sconf/202128008011