Coal is a fossil fuel extracted from the ground by underground mining or open-pit mining (strip mining).
It is a readily combustible black or brownish-black sedimentary rock.
Often associated with the Industrial Revolution, coal remains an enormously important fuel and is the largest single source of electricity world-wide.
In the United States, for example, the burning of coal generates 50% of the electricity consumed.
For more information about the topic Coal, read the full article at Wikipedia.org, or see the following related articles:
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