|Coal ~ Bitumen
coal or black coal is a relatively soft coal containing a tarlike
substance called bitumen. It is of higher quality than lignite coal but
of poorer quality than anthracite. Formation is usually the result of
high pressure being exerted on lignite. Its coloration can be black or
sometimes dark brown; often there are well-defined bands of bright and
dull material within the seams. These distinctive sequences, which are
classified according to either "dull, bright-banded" or "bright,
dull-banded", is how bituminous coals are stratigraphically identified.
Bituminous coal is an organic sedimentary rock formed by diagenetic and
sub metamorphic compression of peat bog material. Its primary
constituents are macerals: vitrinite, and liptinite. The carbon content
of bituminous coal is around 60-80%; the rest is composed of water, air,
hydrogen, and sulphur, which have not been driven off from the
macerals. Bank density is approximately 1346 kg/m³ (84 lb/ft³). Bulk
density typically runs to 833 kg/m³ (52 lb/ft³). The heat content of
bituminous coal ranges from 24 to 35 MJ/kg (21 million to 30 million BTU
per short ton) on a moist, mineral-matter-free basis.
Within the coal mining industry, this type of coal is known for
releasing the largest amounts of firedamp, a dangerous mixture of gases
that can cause underground explosions. Extraction of bituminous coal
demands the highest safety procedures involving attentive gas
monitoring, good ventilation and vigilant site management.
COAL IN UTAH _ BLM