Chapter One COAL One of the most important natural fuels coal was formed from plant life buried in the Earth millions of years ago A hydrocarbon coal is classified in ranks or types according to the amount of heat it produces This depends upon the amount of fixed carbon it contains The ranks in increasing order are lignite or brown coal subbituminous coal or very soft coal bituminous coal or soft coal and anthracite or hard coal Bituminous coal is the most abundant type Coal is most commonly used to produce electricity in power plants It also is an important fuel for heating and powering industrial and manufacturing facilities and for making steel The many chemicals derived from coal are used in industrial processes and in the 8
COAL manufacture of nylon paints plastics synthetic rubber rubber aspirin and thousands of other useful products WHERE COAL IS FOUND China is estimated to have the largest recoverable coal reserves in the world about 45 percent of the world’s total The United States has about 23 percent of the total The United States recoverable reserves are estimated at 265 billion tons 240 billion metric tons enough to last about 250 years at present consumption consumption rates This map shows where deposits of various types of coal can be found around the world 9
FOSSIL FUELS There are about 2,500 coal mines in the United States The productivity of these mines measured in tons per miner per hour has nearly tripled over the past 30 years because of increased use of modern mining machinery The total value of the more than 900 million metric tons of coal produced annually in the United States averages over 20 billion The chief coal-producing states are Wyoming Kentucky West Virginia Pennsylvania Illinois and Texas Anthracite is mined only in Pennsylvania but other states have small deposits Electric utilities are the major consumers of coal in the United States The second largest US market is industrial and retail coal use followed by steel production US coal exports exceed 100 million tons annually with a value of about 4 billion HOW COAL FORMED The world’s coal beds have resulted mainly from the abundance of trees ferns and other plants that existed in the tropiclike forests of the Mississippian and Pennsylvanian Pennsylvanian geological periods These periods called Lower and Upper Carboniferous in Europe and commonly commonly known as the Coal Age lasted for approximately approximately 60 million years from about 358 million to 298 10
COAL million years ago The major high-quality coal deposits are found primarily in the strata or layers of the Pennsylvanian Pennsylvanian period After plant life died it fell into swamp water where it partially decomposed into a slimy colloidal colloidal mass and formed peat As the seas advanced and receded in cycles over the Earth they deposited heavy layers of sandstone shale and other rocks on top of the peat The increased pressures and heat that resulted from the overlying strata caused the buried peat to dry and harden into lignite a low-grade coal Under the OTHER SOLID FOSSIL FUELS Peat and coke are solid fossil fuels that are commonly used today Peat is used as a heating fuel in areas where other fuels are not available It is not an efficient efficient fuel because it burns slowly producing much smoke and little heat Coke is a residue that remains after gases and tar are extracted from some types of coal It is useful in industry because it produces intense heat without smoke Coke is widely used in blast furnaces to make iron and in other metallurgical processes 11
