Coal is a fossil fuel that formed slowly in the bowels of the earth from the remnants of submerged forests. It can be found in many regions worldwide and is still relatively abundant. It is extracted in open pits or underground mines. Coal has been used for thousands of years and today is mainly used to produce electricity.Coal has been known to humankind since ancient times. The Chinese were already extracting it 3000 years ago and according to the Greek philosopher Theophrastus, blacksmiths were using it in the Middle East as far back as the fourth century B.C.

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