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Bituminous coal is a particular rank of coal, as determined by the amount and type of carbon present in the coal and the amount of energy it can produce when burned. [2] It is higher in rank than sub-bituminous coal but lower in rank than anthracite. [3] Bituminous coal is the most abundant rank of coal. [3] [2]
The rank of coal is correlated with its geologic history, as described in Hilt's law. In the ASTM system, any coal with more than 69% fixed carbon is classified by its content of carbon and volatiles. Coal with less than 69% fixed carbon is classified by its heating value. Volatiles and carbon are on a dry mineral free base; heating value is ...
Mohs hardness kit, containing one specimen of each mineral on the ten-point hardness scale The Mohs scale ( / m oʊ z / MOHZ ) of mineral hardness is a qualitative ordinal scale , from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material.
The Mohs scale of mineral hardness; The Vickers hardness test; The Brinell scale; The Janka hardness test; The Rockwell scale; The Durometer scale; The Barcol scale;
Sub-bituminous coal, whose properties range between those of lignite and those of bituminous coal, is used primarily as fuel for steam-electric power generation. Bituminous coal , a dense sedimentary rock, usually black, but sometimes dark brown, often with well-defined bands of bright and dull material.
[1] [2] The most common types include coal, lignite, oil shale, or black shale. [2] The organic material may be disseminated throughout the rock giving it a uniform dark color, and/or it may be present as discrete occurrences of tar , bitumen , asphalt, petroleum , coal or carbonaceous material.
Anthracite, also known as hard coal and black coal, is a hard, compact variety of coal that has a submetallic lustre. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the highest ranking of coals.
Cannel coal from the Pennsylvanian of NE Ohio. Cannel coal or candle coal is a type of bituminous coal, [1] also classified as terrestrial type oil shale. [2] [3] [4] Due to its physical morphology and low mineral content cannel coal is considered to be coal but by its texture and composition of the organic matter it is considered to be oil shale. [5]