Coal refers to a combustible black or brownish-black sedimentary rock composed mostly of carbon and hydrocarbons. It is the most abundant fossil fuel produced in the United States.

Coal is a nonrenewable energy source because it takes millions of years to create. The energy in coal comes from the energy stored by plants that lived hundreds of millions of years ago, when the earth was partly covered with swampy forests. For millions of years, a layer of dead plants at the bottom of the swamps was covered by layers of water and dirt, trapping the energy of the dead plants. The heat and pressure from the top layers helped the plant remains turn into what we today call coal.

-see also:
"Coal" is in the NAICS Code "2121"
  (Coal MiningCoal Mining)


"Coal" is in the CPC Code "11"
  Coal and lignite ; peat

"Coal" is in the HS Code "2705"
  Coal Gas, Water Gas, Producer Gas And Similar Gases, Other Than Petroleum Gases And Other Gaseous Hy

"Coal" is in the UNSPSC Code "15101601"
  Coal
Ref: 86444/2006-09-14

Other Database Pages Exist for this Phrase:
Coal preparation (Coal preparation is the process of sizing and ...)
Subbituminous coal (Subbituminous coal - A coal whose properties ...)
Bituminous coal (A Bituminous coal is a dense, black, soft coal, ...)
Bituminous coal (Bituminous coal is characterized as a dense coal ...)
Coal coke (A Coal coke is a hard, porous product made from ...)


List of books: Coal

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