Monday, May 26, 2014
 |
| Source : moneylife.in |
Coal (from
the Old English term col, which has meant "mineral of fossilized
carbon" since the 13th century) is a combustible black
or brownish-black sedimentary rock usually occurring in rock strata in
layers or veins called coal beds or coal seams. The harder
forms, such as anthracite coal, can be regarded as metamorphic
rock because of later exposure to elevated temperature and pressure.
Coal is composed primarily of carbon along with variable quantities of other elements,chiefly hydrogen, sulfur, oxygen, and nitrogen.
Throughout
history, coal has been used as an energy resource, primarily burned for the
production of electricity and/or heat, and is also used for industrial
purposes, such as refining metals. A fossil fuel,
coal forms when dead plant matter is converted into peat, which in turn is
converted into lignite, then sub-bituminous coal, after that bituminous coal,
and lastly anthracite. This involves biological and geological processes
that take place over a long period. The Energy Information Administration estimates
coal reserves at 948×109 short tons (860 Gt).
One estimate for resources is 18 000
Gt (Wikipedia).
According to the author's view : "coal is an organic substance of ferns are sedimented in a basin, where coal is formed at high temperatures and pressures, coal is a sedimentary rock that can be burned and used as fuel energy,formed over thousands and even millions years."
Source : Wikipedia
