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see dampdamp,
in mining, any mixture of gases in an underground mine, especially oxygen-deficient or noxious gases. The term damp probably is derived from the German dampf, meaning fog or vapor. Several distinct types of damp are recognized.
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a combustible gas released usually in coal mines, less often in salt, metal-ore, and sulfur mines. Firedamp is colorless, lighter than air (since it consists mainly of methane), and contains nitrogen, neon, argon, hydrogen, and carbon dioxide and traces of ethane, propane, ethylene, and other hydrocarbons. In mineral deposits it results from the decomposition of organic substances caused by microorganisms, heat, pressure, and sometimes radiation. When the content of firedamp in the air is from 5 to 16 percent (as measured by methane content), the mixture produced can be ignited by a flame or sparks and cause explosions and fires.

Permissible firedamp concentrations range from 0.5 to 2 percent. The explosive accumulation of the gas is lowered by mine ventilation. Special safety lighting and electrical equipment is used to prevent firedamp from igniting. Firedamp in a mine atmosphere reduces the concentration of oxygen, which may lead to suffocation.


(mining engineering)
A gas formed in mines by decomposition of coal or other carbonaceous matter; consists chiefly of methane and is combustible.
An airtight stopping to isolate an underground fire and to prevent the inflow of fresh air and the outflow of foul air. Also known as fire wall.
References in periodicals archive ?
Stephenson's was based on the fact that an explosion could be prevented if the "burnt" air was contained above the flame, with the firedamp coming in from below and burning on the way up.
Firedamp explosion in Dursunbey revealed that those who added value to the country in hard works were not valued.
The smell of firedamp, a mix of explosive gases found underground, was a sign that they may have `holed', breaking through to disused waterlogged workings of the Brockwell seam.
The mesh enables sufficient air to pass through to support combustion (thus keeping the lamp lit) but the holes are too fine to allow a flame to propagate out and ignite any firedamp outside the mesh.
Another firedamp explosion occurred in a coal mine in northwestern province of Balikesir, where 17 people had died four years ago.
Methane gas - the deadly firedamp of the - impeded rescue operations.
These children worked long shifts in darkness for pennies but their role was vital, preventing the build-up of combustible gas known as firedamp.
Methane gas - the deadly firedamp of the mines - impeded rescue operations.
The disaster was blamed on the ignition of coal dust following an explosion of firedamp.
20am, a cutter struck pyrites, igniting firedamp and causing the massive explosion which brought down 120 yards of roof.
By 1960 the colliery employed 650 men producing 30,757 tonnes of coal with the constant danger of outbursts of coal and firedamp from the deep anthracite seams, one ouburst claimed the lives of six miners in 1971.