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A coal breaker is a coal processing plant which breaks coal into various useful sizes. Coal breakers also remove impurities from the coal (typically slate) and deposit them into a culm dump. The coal breaker is a forerunner of the modern coal preparation plant.〔Carris, David M. "A Historic Perspective." In ''Designing the Coal Preparation Plant of the Future.'' Barbara J. Arnold, Mark S. Klima, and Peter J. Bethell, eds. Littleton, Colo.: Society for Mining, Metallurgy and Exploration, 2007. ISBN 0-87335-257-2〕 Generally speaking, a coal tipple was typically used at a bituminous coal mine, where removing impurities was important but sorting by size was only a secondary, minor concern.〔〔 Coal breakers were always used (with or without a tipple) at anthracite mines.〔 While tipples were used around the world, coal breakers were used primarily in the United States in the state of Pennsylvania (where, between 1800 and the mid-20th century, many of the world's known anthracite reserves were located).〔〔Rottenberg, Dan. ''In the Kingdom of Coal: An American Family and the Rock That Changed the World.'' Florence, Ky.: Routledge, 2003. ISBN 0-415-93522-9〕〔As of 2007, the vast majority of proven anthracite coal reserves were located primarily in Asia. The following anthracite coal producing nations held the following estimated reserves: Russia, 6,870 megatonnes (MT); China, 6,350 MT; Ukraine, 5,860 MT; Vietnam, 2,230 MT; North Korea, 1,425 MT; South Africa, 710 MT; South Korea, 240 MT; Spain, 195 MT; Canada, 100 MT; Poland, 62.5 MT; and the U.S., 50 MT. See: (Marston, Richard and Ewart, Jr., Don. "Upcoming Trends in World Anthracite Trade." ) ''2d World Anthracite Conference.'' Kiev, Ukraine. September 17–18, 2007.〕 At least one source claims that, in 1873, coal breaking plants were found only at anthracite mines in Pennsylvania.〔Macfarlane, James. ''The Coal-Regions of America: Their Topography, Geology, and Development.'' New York: D. Appleton and Company, 1873.〕 ==Function of a coal breaker== The first function of a coal breaker is to break coal into pieces and sort these pieces into categories of nearly uniform size, a process known as breaking.〔〔Ketchum, Milo Smith. ''The Design of Mine Structures.'' New York: McGraw-Hill, 1912.〕 The second function of a coal breaker is to remove impurities (such as slate or rock), and then grade the coal on the basis of the percent of impurities remaining.〔 The sorting by size is particularly important for anthracite coal. In order to burn efficiently, air must flow evenly around anthracite. Subsequently, most anthracite coal is sold in uniform sizes. In the 1910s, there were six commercial sizes of coal (with the smallest size having three subsets):〔〔International Textbook Company. ''International Library of Technology: A Series of Textbooks for Persons Engaged in the Engineering Professions and Trades.'' Vol. 38. Scranton, Pa.: International Textbook Co., 1903.〕〔〔 *Steam - 4.5 to 6 inches in size (primarily used as steamship fuel). *Broken - 3.25 to 4.5 inches in size. *Egg - 2.25 to 2.3 inches in size. *Stove - 1.5 to 1.625 inches in size (primarily used for use in home cooking stoves). *Chestnut - 0.875 to 0.9375 inches in size. *Pea - 0.5 to 0.625 inches in size. There were three subsets of "pea coal": * *No. 1 Buckwheat - 0.25 to 0.3125 inches in size. * *No. 2 Buckwheat - 0.1875 inches in size. * *No. 3 Buckwheat - 0.09375 to 0.125 inches in size. Coal pieces smaller than 0.09375 inches in size were considered "culm," and unable to be separated from the impurities (and thus useless).〔 The grade of coal ranged from a low of 5 percent impurities for steam or broken coal to a high of 15 percent for pea-size coal and its subsets.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「coal breaker」の詳細全文を読む スポンサード リンク
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