http://resource.geosciml.org/classifier/cgi/commodity-code/black-coal
alt label |
|
||||||
---|---|---|---|---|---|---|---|
broader |
|
||||||
definition | Bituminous coal or black coal is a moderately hard coal containing higher carbon and fewer impurities than lignite coal but of poorer quality than anthracite. 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. | ||||||
notation |
|
||||||
source | http://en.wikipedia.org/wiki/Black_coal | ||||||
type |
|
||||||
in scheme | commodity-code original |