Cannel coal, also known as
candle
coal, is a type of
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. 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 gas-making. This, although of very small value as fuel,
commands a specially high price for gas-making. Cannel is more
compact and duller than ordinary coal, and can be wrought 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.
In 1540,
an antiquary named John Leland reported that Sir Roger
Bradshaigh had discovered a plentiful
shallow seam of smooth, hard, Cannel Coal on his estate, near
Haigh, Greater
Manchester
. The deposit came to be known as the
Great Haigh fault. The shallow depth of the Cannel meant
that 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. Widely used for domestic
lighting in the early 19th Century, before the incandescent
gas mantle was available, it gradually
lost favour; as the use of
coal gas made it
obsolete.
On
October 17, 1850,
James Young, of
Glasgow
, Scotland, patented a method for the extraction of
paraffin ("kerosene" in North America) from cannel
coal.
See also
Sources
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