coal

[gerger]

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[tartanwiz]

Coal is a black carbon mineral made by the fossilization of trees from the Carboniferous period of the Earth, 400 million years ago. The trees would grow and die and the rotting wood would lie in layers. Eventually these became covered in rock as the earths crust shifted and changed, and the coal-forming trees were pressure-cooked under the ground at great weight and heat, forming a solid black flammable substance. Coal has been mined since ancient times, first from outcrops on the surface, then dug from small pits. The industrial Revolution turned mining into an industry, requiring mines with great shafts and tunnels miles long as the miners cut out the coal from the seams, sometimes even under the sea bed. Production and safety were improved in the 20th century with safer lamps, tungsten carbide drilling and conveyor belts. Coal has been replaced in recent years by other forms of fuel or energy and this will continue as coal smoke is harmful to the atmosphere. Hope I've helped.