Verfahren und Vorrichtung zur UEberwachung von Brandstellen in untertaegigen Grubenanlagen

Underground fires are monitored by inserting an expendible sniffler tube 3 through a firewall 2 isolating a section where the fire has broken out, drawing gas samples through the tube for analysis at an observation station, and determining the length of tube undamaged by the fire to find the extent of the fire. The determination of length is preferably effected electrically, the sniffler tube containing at least two mutually insulated electrical conductors extending along its length with ability to make contact locally in the vicinity of the fire by the effect of the heat.