[Fire fighting with nitrogen in the German coal mining industry]

Fire-fighting methods using inert gases have been known for decades. In December 1974, for the first time in the German coalmining industry, liquid nitrogen was gasified at the surface and fed to a mine fire underground. This developed into a standard fire-fighting procedure in mines and has been used in numerous cases. The great advantage of this method for the mine rescue operations is the elimination of explosion hazards and the possibility to create better working conditions. The example of a large scale fire in 1982 illustrates how fire zones can be stopped and reopened in immediate succession, if some requirements are fulfilled. The neutralization method sets new technical and safety tasks for the mine rescue services. Instruction on working in a low oxygen environment now represents a particularly important part of their training.