Sub-bituminous coal is a
coal whose properties range from those of
lignite to those of
bituminous coal and are used primarily as fuel for
steam-electric power generation. It may be dull, dark brown to black, soft and crumbly at the lower end of the range, to bright,
jet-black, hard, and relatively strong at the upper end. Subbituminous coal contains 20 to 30 percent inherent moisture by weight. The heat content of sub-bituminous coal ranges from 17 to 24 million
British thermal units per
short ton (20 to 28
Megajoules per
Kilogram) on a moist, mineral-matter-free basis. The heat content of sub-bituminous coal consumed in the
United States averages 17 to 18 million Btu/ton (20 to 21 MJ/kg), on the as-received basis (i.e., containing both inherent moisture and mineral matter). A major source of sub-bituminous coal in the United States is the
Powder River Basin in
Wyoming.
See more at Wikipedia.org...