Louisiana State Rock
Lignite Coal STATUS Unofficial DESCRIPTION Lignite is a soft, low-carbon variety of coal. Coal, a brittle, combustible, black or dark brown sedimentary rock, forms from decomposed plant matter that has been subjected to high temperatures. Coal is composed primarily of carbon, with traces of sulfur, hydrogen, and nitrogen. It is grouped into four ranks according to its carbon content. Lignite, the "youngest" form of coal, has less than 85 percent carbon. In ascending order, the other ranks are sub-bituminous (at least 85 percent carbon), bituminous (at least 90 percent), and anthracite (95 percent carbon). Lignite is divided into two classes, lignite "A" and lignite "B," according to energy density. Louisiana’s lignite, with a heat content of about 7,000 Btu/lb., is class "A." Its sulfur content averages 0.64 percent by weight, qualifying it as a "low-sulfur" coal (a low-sulfur coal contains less than one percent sulfur).  A STATE SYMBOL While Louisiana has never designated an official state rock, lignite coal is an obvious choice because of its importance in the state and to the nation. Coal was known to exist in Louisiana as early as 1812, a handful of years after the Louisiana Purchase. It has since been found to underlie 1,360 square miles in the state, part of the geologic complex known as the Wilcox Group. During the Civil War, lignite was used at the federal arsenal near Shreveport, and during the next few decades it powered steamboats, railroads, and forges. However, this lignite came from outcrops and required no substantial effort to obtain. Major production of lignite did not become economically viable until the energy crisis of the 1970s, when the U.S. was looking for greater domestic sources of fuel to generate electricity. Large-scale surface mining of lignite began in 1986, and a 640-megawatt power plant was constructed nearby. This electrical operation, which provides 25 percent of the state’s energy, uses both local lignite and coal from other states.  FORMATION Coal formation began about 350 million years ago, early 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. Louisiana’s lignite is a component of the Wilcox Group, an Eocene (34 to 56 million years ago) geological complex that provides several resources to the state. In addition to the six-foot-thick seam of lignite in De Soto Parish, the Wilcox houses stores of freshwater, natural gas, and petroleum.   USES Coal has been used for centuries as a direct source of heat by burning it in coal stoves. In modern times, the most familiar use of coal is charcoal briquettes, some of which are in fact made of Louisiana lignite. However, the greatest demand for coal today 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 applications 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, including paper, creosote, benzene, ammonia, pharmaceuticals, fibers (rayon, nylon), dyes, and solvents. GEOGRAPHIC DISTRIBUTION AND PRODUCTION Louisiana’s harvestable lignite is limited to De Soto Parish. In 2008, three million tons of lignite were produced from the two De Soto Parish mines. Total U.S. production of lignite in 2008 was 76 million tons, while the total of all ranks of coal was 1.2 billion tons. World production of all ranks of coal in 2008 was 6.8 billion tons. Recoverable coal exists in about 70 countries. The U.S, Russia, China, and India have by far the largest proven reserves of coal.	Cliffs Showing Band of Lignite Lignite Deposits Mining Lignite Lignite (Jet) Sample COAL FACTS Name: Coal Chemical Formula: FeS2 Color: Black to dark brown
	Author: World Trade Press