Utah State Rock
Coal is a brittle, combustible, black or dark brown sedimentary rock formed from decomposed plant matter. It is composed primarily of carbon, with traces of sulfur, hydrogen, and nitrogen. Coal is grouped into four ranks according to its carbon content. Anthracite, the highest rank, is over 95 percent carbon and has been partially metamorphosed. In descending rank, the other coals are bituminous (at least 90 percent carbon), sub-bituminous (at least 85 percent), and lignite, which grades into peat.
A STATE SYMBOL
Utah designated coal as its official state rock in 1991, commemorating the importance of this resource throughout the state’s development. Utah was a sparsely settled territory in 1854, when a respected Ute named Tabiuna gave a piece of coal to Brigham Young. Young, the leader of the Mormon colony and the territorial governor, learning that two Welsh immigrants among his followers had been coal miners, sent them with Tabiuna to the source of the coal. Utah’s first mine was soon established in what became the town of Wales.
Larger coal deposits were found in 1858 near the town of Chalk Creek (now Coalville). Again, Brigham Young sent settlers to start a mine there, the first of seven in the area. The coal was hauled to Salt Lake City by ox teams until 1873, when a narrow gauge railroad, the Utah Eastern Narrow Gauge, was built to transport the coal. From this point on, yearly coal production in the state would rise to five million tons by 1920 and over 15 million by 1990. The amount today is about 24 million tons annually.
Coal formation began 350 million years ago in the Carboniferous Period, a time of mild climate and prevalent swamplands. Throughout millions of years, swamp plants that died built up in layers of peat, which was initially about 90 percent water. Aerobic decay in the upper layers of the swamp began the decomposition process, reducing the volume of the organic matter.
Beneath these upper layers, where oxygen did not penetrate, anaerobic bacteria further broke down the plant remains. These bacteria gave off acids, which, at still deeper levels, became too concentrated for bacteria to live. The acidic, anaerobic plant matter had by this time been transformed into a black gel known as gytta, and it no longer underwent decomposition.
The next step in the development of coal was bituminization, which occurred over millions of years as a sedimentary blanket thousands of feet thick buried the ancient swamps, trapping heat rising from deep in the earth. The high temperatures caused the water content to be cooked out of the peat until it formed lignite. If the process continued long enough, the water and organic matter in the peat continued to be forced out, creating purer coal.
Seventeen of Utah's 29 counties contain reserves of coal. Active mines operate in Carbon, Emery, and Sevier counties. Worldwide, recoverable coal exists in about 70 countries. The U.S, Russia, China, and India have by far the largest proven reserves of coal.
Coal has been burned in stoves for centuries as a direct source of heat. In modern times, the greatest demand for coal is industrial. Electricity generation from "steam coal" is the most significant of these uses; worldwide, 41.5 percent of electricity is produced in coal-fired power plants.
Coal has other uses besides generating energy. The manufacture of steel requires carbon, most often obtained from metallurgical (hard) coal. Thirteen percent of the world’s hard coal is used to make steel. A surprising array of products is made using coal or its by-products: paper, creosote, benzene, ammonia, pharmaceuticals, fibers (rayon, nylon), dyes, and solvents.
In 2008, Utah mined 24.3 million tons of coal valued at $674 million. Utah coal was shipped to 16 states. In the same year, total U.S. production was 1.2 billion tons, while the world total was 6.8 billion tons.
Chemical Formula: C
|Author: World Trade Press|