Culm coal
Culm coal is a term with several regional meanings, but it generally refers to **fine**, **waste** or low-grade coal material associated with mining and processing. This article reviews the nature…
G-grade coal
This article examines the properties, distribution, economic role and industrial significance of a category frequently referred to as G-grade coal. The term can have several meanings depending on national standards…
Semi-anthracite
Semi-anthracite is a distinct rank of coal that occupies a middle ground between high-grade anthracite and the more common bituminous coals. It combines many of the advantageous physical and chemical…
