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Show 30A April Energy 2002 Underground mining accounts for 40 percent of coal: (Continued from page 10A) hundreds of feet long. The loosened coal falls onto a conveyor for removal from the mine. Longwall systems have hydraulic roof supports that levels off production, but also increases miner safety. Newer versions of the long-wa-ll employ sensors to detect how much coal remains in the seam being mined, as well as robotic controls to enhance effi- The continuous mining machine tears the coal from a seam in the mine and automatically removes the fossil fuel from the area by conveyor. d continuous miners allow an operator to direct the machine from a distance, increasing safety. that begins with cutting the bed so the coal will break easily when blasted with explosives. Once the coal is blasted, the pieces are removed from the working sites. Conventional mining can be a practical and economical method in situations where "geology is favor- now possible. tinuous mining machine and accompanying movable roof Remote-controlle- fuIn the ture, robotic versions of these machines now under development will allow fin: enhanced automatic operations and even greater efficiencies than are ciency. In general, longwalls can increase the average coal recoverability rate to as much as 80 percent, and they have had an important impact in helping to increase underground coal mine productivity. Continuous - The process still accounts for a significant amount or about 43 percent of coal removed from deep mines. But the continuous mining methods role is undergoing a mqjor transformation due to the rapid development of long-wa- ll technology. The production process utilizes a specialized cutting machine that mechanizes the extraction procedure: the continuous miner. Although still utilized in stand-alon- e production operations, continuous miners are increasingly employed for main mine entry and longwall panel development. Some underground coal facilities are hybrid operations, utilizing both longwall and continuous mining methods for coal production. Conventional - The conven- tional coal production process is one ofthe oldest methods of mining the fossil fuel, although the process is not as commonly used today as earlier in the 20th century. Conventional mining consists of a series of operations 7 K V ..A . j 'tttt&trzzi-rr- '., rrm?m,V?y ! able. Shortwall - Shortwall mining currently accounts for less than 1 percent of annual deep mine production. It involves the use of a consupports. Ihe continuous miner 0 feet shears coal panels e wide and more than long. Coal is removed from under150-20- half-a-mil- ground mines by two basic methods: shuttle cars, which take coal to a central loading area in the mine; and belt conveyors, which remove coal to thesurface. In recent years, both the mobility and capacity of conveyor system has increased, helping to improve the efficiency of coal removal. The introduction of diesel shuttle cars has also improved the coal removal process. cage protects the operators of continuous miners. The process accounts for a significant amount of coal removed from deep mines. But the continuous mining method's role is undergoing a major transformation due to the rapid development of longwall technology. A metal |