Coal dust explosion
A coal dust explosion is the explosive reaction of coal dust ( dust explosion ) with atmospheric oxygen , which is particularly feared in coal mining .
Coal dust explosions are the cause of numerous mine accidents in hard coal , and more rarely in lignite mining . They occur preferentially in the wake of mine gas explosions , since firedamp explosions stir up existing coal dust and can subsequently ignite. They can, however, also occur without a preceding storm if finely distributed coal that has been blown up in some other way reacts with atmospheric oxygen through sparks, heated device parts or the like. Coal dust explosions can also occur while grinding and drying coal and filling coal dust silos.
Coal dust explosions can significantly increase the destructive effect of hitting weather. Their prophylaxis is therefore an essential part of (coal) mine safety. The main protective measures are good weather management (fresh air supply and air exchange) within the mine in order to prevent ignitable mine gas concentrations as the main cause, avoiding the whirling up of pulverized coal for example by sprinkling with water during mining and transport, avoiding the spontaneous combustion of coal on the mining front and using firedamp-proof explosives. Furthermore, the risk of extracting coal dust that has already arisen and protecting machines (e.g. by encapsulating electrical components; automatic shutdowns when mine gases are detected) is reduced.
Preventive measures such as rock dust barriers (rock dust accumulated on tiltable surfaces, which, after being swirled by a possible mine gas explosion, is intended to break the chain reactions of the coal dust by internal reaction blockade) were often used in the 19th century, but were not sufficiently satisfactory and have therefore also become more effective in more recent times replaced by turbulence, water barriers.
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Individual evidence
- ↑ VDI 2263: 1992-05 Dust fires and dust explosions; Dangers, assessments, protective measures (Dust fires and dust explosions; hazards, assessment, protective measures). Beuth Verlag, Berlin, p. 6.
- ^ Fritz Heise, Friedrich Herbst: Textbook of mining studies. With special consideration of hard coal mining. Volume 2. Springer, Berlin 1910.