Coal is a black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements; chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal are found in many parts of the world.
It is estimated that there are more than 10 billion tonnes (gigatonnes) of recoverable reserves worldwide – this means that there is enough coal to last us around 150 years at current rates of consumption. However, it should be noted that global production has been increasing steadily over the past few decades and now stands at almost 8 billion tonnes per year
Coal
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