Hierarchy classification:

1. top of the aat hierarchies
2. Materials Facet
3. Materials (hierarchy name)
4. materials (substances)
5. [materials by composition]
6. organic material
7. bituminous material
8. natural bituminous material
9. pyrobitumen
10. coal

Anotations

Scope note:

A relatively soft coal containing the tarlike substance asphaltic bitumen. Its carbon content is 60-80%, the rest composed of water, air, hydrogen, and sulfur. It is of higher quality than lignite coal but of poorer quality than anthracite. It was usually formed as a result of high pressure on lignite. It dark brown to black in color, commonly banded or layered. The major problem with burning of bituminous coal is air pollution. A relatively soft coal containing the tarlike substance asphaltic bitumen. Its carbon content is 60-80%, the rest composed of water, air, hydrogen, and sulfur. It is of higher quality than lignite coal but of poorer quality than anthracite. It was usually formed as a result of high pressure on lignite. It dark brown to black in color, commonly banded or layered. The major problem with burning of bituminous coal is air pollution.