When the figure is not level people cannot know what is meant by width, depth, or height without being told (or without labels), although length is generally still assumed to mean the direction in which the figure is longest..
The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure. Coal is composed primarily of carbon along with variable quantities of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.oal is primarily used as a solid fuel to produce electricity and heat through combustion. World coal consumption was about 7.25 billion tonnes in 2010 (7.99 billion short tons) and is expected to increase 48% to 9.05 billion tonnes (9.98 billion short tons) by 2030.
The coal tars used are products of the destructive distillation of chosen grades of coal having low ash and good coking quality which produces a selective low carbon tar.Coal tar is the primary condensation product resulting from the carbonization of coal for making coke or gas; the tar is produced as a by-product.one Star coal tar coatings are products of carefully chosen coal tars having low carbon values, carefully blended with mineral fillers, carbon plasticizers and selected grades of heavy oils and solvents distilled from coal tar.