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Fossil Fuels: Coal

Coal is a combustible dark rock formed underground by geologic processes. Coal is a finite, carbon-based energy resource that is burned to produce steam, which in turn produces electricity. The exact composition of coal can vary based on where it was mined.

All Coal is Not Created Equal
Types of coal are ranked by energy, carbon content, and usage.

Anthracite Coal
Characteristics of anthracite coal, the highest ranked coal for heat content.

Bituminous Coal
Characteristics of bituminous coal.

Sub-Bituminous Coal
Characteristics of Sub-Bituminous Coal.

Lignite
Characteristics of lignite, also known as brown coal.

Hazardous Emissions from Coal Combustion
Burning coal releases a variety of pollutants.

Comparative Ranking of Coal
Types of coal are ranked by energy, carbon content, and usage.

Hidden Cost of Coal
Harvard study says coal price does not reveal true costs.

Coal Calculator Converts Energy, Mass, and Properties - Coalportal.com
This interactive calculator allows you to convert energy, mass, and compositional properties of coal into different units of measure.

Coal in a Nutshell
This page from About.com's geology guide explains the basics of coal.

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