Porous coal
Porous coal is a variant of coal characterized by a pronounced internal network of voids and channels that significantly influence its physical, chemical and economic behavior. Unlike dense, massive coal,…
Dense coal
Dense coal occupies a special place among the variety of coal types because of its high material compactness, elevated fixed carbon and calorific value, and specific industrial applications. In this…
Shatter-prone coal
The phenomenon of coal that readily breaks into smaller pieces during extraction and handling — commonly referred to as shatter-prone coal — presents a set of geological, operational and economic…
Cleated coal
Cleated coal is not a separate type of fuel but a descriptive term used by geologists and mining engineers to refer to coal seams that contain a well-developed system of…
Fractured coal
The term fractured coal refers to coal seams that contain pervasive natural cracks, joints and cleats which greatly influence their mechanical behavior, permeability and economic value. Fracturing may be the…
Raw anthracite
Raw anthracite is one of the highest-ranking coals in terms of carbon content and energy density. It has been valued for centuries for its distinctive physical and chemical properties, and…
Raw sub-bituminous coal
This article examines raw sub-bituminous coal: its nature, where it occurs, how and where it is mined, its economic and industrial roles, and environmental and policy considerations. Sub-bituminous coal occupies…
Raw bituminous coal
Raw bituminous coal is one of the most important fossil fuels in the modern economy. It occupies an intermediate rank in the coalification process between subbituminous coal and anthracite, offering…
Raw lignite
This article explores raw lignite — a low-rank form of coal commonly called brown coal — examining its geological origins, where it is found and mined, its role in modern…
Slack coal
This article examines slack coal — a term used in coal-producing regions to describe the small pieces, fragments and fines that remain after mining and initial processing. Although often treated…
