This report describes the operation and maintenance of a mobile inert gas generator for use in a remote sealing system for fighting underground coal mine fires. Seals are emplaced in mine passageways between the fire zone and the rest of the mine isolating the fire zone. The seals consist of fly ash that has been pneumatically conveyed by inert gas through a borehole connecting the surface and the passageway. Inert gas is used as the fly ash transport medium (instead of fresh air) since the introduction of large volumes of fresh air in the vicinity of the fire zone would be undesirable. The inert gas generatory has been performance tested and operated in the field for approximately 200 hours. The system is currently available for fighting any future underground coal mine fire.