Deposits, composition and uses of coal

Hard coal, representing over 50% of the fossil raw materials, is the carbonaceous material with by far the greatest availability. Confirmed world resources of hard coal are around 6,900 billion t of these, some 550 billion t can be recovered by current mining techniques. Brown coal deposits total some 6,500 billion t, of which 430 billion t are recoverable. In comparison with coal reserves, economically recoverable oil reserves are only 95 billion t, and natural gas deposits 90,000 billion m (around 72 billion t). 

In brown coal, the proportion of aromatic structures is considerably lower than in hard coal. Anthracite exhibits a particularly high degree of aromatization, because of its great geological age. 

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