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Damp is the collective name given to all gases (other than air) found in coal mines in Great Britain and North America. [1]As well as firedamp, other damps include blackdamp (nonbreathable mixture of carbon dioxide, water vapour and other gases); whitedamp (carbon monoxide and other gases produced by combustion); poisonous, explosive stinkdamp (hydrogen sulfide), with its characteristic rotten ...
Mining accidents can occur from a variety of causes, including leaks of poisonous gases such as hydrogen sulfide [2] or explosive natural gases, especially firedamp or methane, [3] dust explosions, collapsing of mine stopes, mining-induced seismicity, flooding, or general mechanical errors from improperly used or malfunctioning mining equipment (such as safety lamps or electrical equipment).
The explosion was caused by firedamp ignited by a 'flash' from a damaged cable. [8] On 4 December 1981, Reginald Canham was killed in an accident aged 57 leaving a wife and two children, one of the last fatalities before its closure. [citation needed] The colliery was closed on 16 June 1989. [3]
The firedamp leaking from the void above the goaf was ignited. When firedamp explodes in a tunnel it generates a blast of gas which raises any coal dust lying around. The coal dust, being finely divided, in turn explodes and the resulting explosion propagates along the tunnel as a flame front.
Mine rescue teams are trained in first aid, the use of a variety of tools, and the operation of self-contained breathing apparatus (SCBA) to work in passages filled with mine gases such as firedamp, afterdamp, chokedamp, and sometimes shallow submersion. From 1989 to 2004, the SEFA backpack SCBA was made.
The term is etymologically and practically related to other terms for underground mine gases—such as firedamp, white damp, and black damp, with afterdamp being composed, rather, primarily by carbon dioxide, carbon monoxide and nitrogen, with highly toxic stinkdamp-constituent hydrogen sulfide possibly also present.
Air enters from the side and spent gases exit from the top. In the presence of firedamp the flame intensifies. The flame must be kept fairly high in normal use, a small flame permits the enclosed space to fill with firedamp/air mixture and the subsequent detonation may pass through the gauze. [49]
On 13 June 1989, the Beijing Public Security Bureau released an order for the arrest of 21 students they identified as the protest leaders. These 21 most-wanted student leaders were part of the Beijing Students Autonomous Federation , [ 249 ] which had been instrumental in the Tiananmen Square protests.