ABSTRACT
Coal type is determined from the examination of polished sections of a coal sample using a reflected-light microscope. Coal rank is the most important property of coal because rank initiates the classification of coal for use. The composition of a coal is typically reported in terms of its proximate analysis and its ultimate analysis. Coal is found throughout the US and the world. It is the most abundant fossil energy resource in the US and the world, comprising 95" of US fossil energy resources and 70" of world fossil energy resources on an energy content basis. Petroleum is refined into petroleum products that are used to meet individual product demands. The cost of transporting coal decreased between 1988 and 1997, due to the increased competition from the low-sulfur western coals following passage of the Clean Air Act Amendments in 1990. The US Geological Survey (USGS) regularly assesses the long-term production potential of worldwide petroleum resources.
