Where Does Coal Come From?

For hundreds of millions of years the world had no coal reserves. So where does coal come from now? Coal is a fossil fuel made from the carbon atoms locked up in plants that lived millions of years ago.

345 to 280 million years ago, the world was mostly covered with luxuriant vegetation which grew in swamps. A large proportion of these plants were types of fern, and some were as big as trees. This vegetation died off and became submerged under water. It gradually decomposed and as it decomposed, the vegetable matter lost oxygen and hydrogen atoms. It left a deposit which contained a high percentage of carbon. Peat was formed first, but over the years layers of sand and mud settled over the peat, from the water. Pressure from the layers above, the movements of the earth’s crust, and at times volcanic heat, compressed and hardened the deposits. Through this process the rock-like material, coal was formed.

Coal is in wide use as a high energy-releasing fuel. Once mined the coal is burned in coal-fired power stations in order to produce electricity. The energy released during the exothermic reaction (combustion) is actually the solar energy from millions of years ago that has been stored in the plant’s roots, stems and leaves. The heat released boils water into steam. The steam then turns a turbine, generating electricity.

Coal, over the years, has been many things to many people. Some became very rich from its trade, others have given their lives mining it. Coal mining in Britain dates back to the Roman times and in China to 200 years before the birth of Jesus Christ. Up to the 18th century coal was only mined near the surface beside outcrops, “bell pits” or “adit mines”. A bell pit was little more than a well which was opened to reach the coal, it was shaped like a bell, hence the name. Many areas had numerous bell pits which were in close proximity to other bell pits, as one collapsed another was opened.

Currently coal is mined in over 100 countries in every continent except Antarctica. US, Russia, China and Australia hold more than half the world’s reserves.

Of the three fossil fuels – coal, oil and natural gas – coal reserves have the most favourable estimates for exhaust rates. Nevertheless without the deployment of carbon capture technology burning coal releases more carbon dioxide and other greenhouse gases than is healthy for the planet and the human population. -E. MESKHI

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