AbstractThe deflagration behaviour of explosives, in particular of permissible explosives, was investigated under various experimental conditions. The initiation of a methane/air mixture was provoked by a deflagrating explosive in a gallery under conditions of low resistance stemming. The results indicate that the initiation probability of an explosive methane/air mixture depends on the chemical reactivity (ignition ability) of the explosive which is low for permissible explosives under the conditions given.