The Górniczy Agregat Gaśniczy (GAG) is a jet engine inertisation unit developed for use in mines, controlling and suppressing coal seam fires and neutralising firedamp situations.
The unit was designed in Poland in the 1970s, its name roughly translates as "Mine Fire Suppression Apparatus".
[1][2] A GAG 3A unit was developed by the Queensland Mines Rescue Service, in association with the Commonwealth Scientific and Industrial Research Organisation (CSIRO).
[4] The gases lower the oxygen levels, suppressing fires, and forcing methane out of the mine.
GAG units have been used in Australia, most notably in 2000 at the Blair Athol Mine, Queensland, where one extinguished a 54-year-old coal fire.