Cannel coal, also known as candle coal, is a type of bituminous coal, also classified as terrestrial type oil shale, with a large amount of hydrogen, which burns easily with a bright light and leaves little ash. Cannel coal consists of micrinites, macerals of the exinite group, and certain inorganic materials. Cannel coal usually occurs at the top or bottom of other coals.
A member of the Bradshaigh family discovered a plentiful shallow seam of smooth, hard, cannel coal on his estate, near Haigh, Greater Manchester. The shallow depth at which it was found meant it was suitable for the simple surface mining methods available at that time. It could be worked and carved, and was an excellent light fuel which burned with a bright flame, it was easily lit and left virtually no ash.
The excess of hydrogen in a coal, above the amount necessary to combine with its oxygen to form water, is known as disposable hydrogen, and is a measure of the fitness of the coal for use in the manufacture of coal gas. Such coal, although of very small value as fuel, commands a specially high price for gas-making. Cannel coal was used as a major feedstock for the historical manufactured gas industry, as the gas produced from it was valuable for lighting due to the luminosity of the flame it produced. Cannel gas was widely used for domestic lighting throughout the 19th century before the invention of the incandescent gas mantle by Carl Auer von Welsbach in the 1880s. Following the introduction of the gas mantle, cannel coal gradually lost favour as a manufactured gas feedstock as the gas mantle could produce large quantities of light without regard for the flame luminosity of the gas burnt.
Cannel is more compact and duller than ordinary coal, and can be worked in the lathe and polished. In the Durham coal-field (and possibly elsewhere) carving cannel coal into ornaments was a popular pastime amongst the miners.
- "Haigh Hall - England". Clanlindsay.com. Retrieved 2013-03-30.
- Coal, 1911 Encyclopædia Britannica
- Haigh, Greater Manchester