Bituminous Coal
Medium-rank coal (carbonaceous, ~45-86% carbon)
A dense, black, mid-rank coal with high energy content, widely used for power generation and to make coke for steelmaking.
- Mohs hardness
- 2-2.5
- Color
- Black to dark brownish-black
- Type
- sedimentary
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Overview
Bituminous coal is a medium-rank coal, harder and richer in carbon than lignite but softer than anthracite. It is dense, black, and usually banded with alternating dull and bright layers, and it has a relatively high heat content that makes it a major energy resource.
It contains a moderate amount of volatile matter and a characteristic bitumen-like binder, giving it its name. When heated in the absence of air it softens and can be converted into coke.
Bituminous coal is the most abundant and widely mined type of coal, central to electricity production and heavy industry worldwide.
Formation & geology
Bituminous coal forms through the deeper burial and heating of lower-rank coals (peat then lignite then sub-bituminous coal). Increasing temperature and pressure over millions of years drive off moisture and volatile compounds and progressively concentrate carbon in the coalification process.
Most bituminous coal originated in vast Carboniferous and Permian swamp forests, with major deposits in the Appalachian and Illinois basins of the United States, as well as China, India, Australia, Russia and Europe. The rank reflects the maximum depth and temperature the original peat experienced during burial.
How to identify it
Bituminous coal is identified by its black color, banded layering, and resinous to dull luster, with bright vitreous bands (vitrain) alternating with duller layers. It is harder and denser than lignite but still soft enough to scratch, and it leaves a black streak that dirties the hands.
It breaks into blocky fragments and burns with a smoky yellow flame. Compared to anthracite it is duller, softer, and less dense, and unlike lignite it shows no brown color or woody texture. Its banding, black streak and moderate hardness are the key field indicators.
Uses & significance
Bituminous coal is a workhorse fuel, burned in power stations to generate electricity (thermal or steam coal) and heated to produce coke, the essential reductant in blast-furnace steelmaking (coking or metallurgical coal).
It is also a feedstock for coal gas, coal tar, and a range of chemical products, and historically powered locomotives and industry. Byproducts of coal processing yield dyes, solvents and pharmaceuticals. Environmental concerns over carbon dioxide, sulfur and particulate emissions are driving a transition away from coal in many regions.
Frequently asked questions
What is bituminous coal used for?
Mainly electricity generation and producing coke for steelmaking, plus a feedstock for coal tar and chemical products.
Is bituminous coal better than lignite?
It has a higher carbon content and energy value than lignite, making it a more efficient fuel, though anthracite ranks higher still.
What is coking coal?
It is a grade of bituminous coal suitable for converting into coke, the carbon material used to smelt iron in blast furnaces.
How can I tell bituminous coal from anthracite?
Bituminous coal is duller, softer and often banded, and it dirties the hands; anthracite is harder, denser, shinier and cleaner to handle.
Bituminous Coal guides
In-depth guides for identifying, valuing, and understanding Bituminous Coal.
