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boghead coal[′bäg‚hed ‚kōl]
a variety of saprolitic coals, formed from water plants. Boghead coal is black-brown, occasionally olive, with a solid, fine-grained structure and shellshaped fracture planes. It is characterized by a high hydrogen content (8 to 12 percent), volatile substances (75 to 90 percent), and a large yield of primary resin (to 50 percent). The calorific value of a burning mass is 33.5–37.7 megajoules per kg (8,000–9,000 kilocalories per kg). The formation of boghead coal takes place under the conditions present in a stagnant reservoir of a lake or lagoon. Boghead coal lies in lenticular layers of comparatively limited distribution (the Podmoskovnii basin). Boghead coal is a valuable raw material for producing artificial liquid fuel, lubricating substances, and valuable resin free of phenols and asphaltenes. Easily hydrolyzed, it forms oil rich in cyclic hydrocarbons.