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Big Muskie was a coal mining Bucyrus-Erie dragline owned by the Central Ohio Coal Company (formerly a division of American Electric Power), weighing nearly and standing nearly 22 stories tall. It operated in the U.S. state of Ohio from 1969 to 1991. ==Design specifications and service== The Big Muskie was a model 4250-W Bucyrus-Erie dragline (the only one ever built). With a bucket, it was the largest single-bucket digging machine ever created and one of the world's largest mobile earth-moving machines alongside the Illinois-based Marion 6360 stripping shovel called The Captain and the German bucket wheel excavators of the Bagger 288 and Bagger 293 family.〔For details see the table on the (German Wiki ).〕 It cost $25 million in 1969, the equivalent of $ today adjusted for inflation. Its bucket could hold two Greyhound buses side by side. It took over 200,000 man hours to construct over a period of about two years. Big Muskie was powered by electricity supplied at 13,800 volts via a trailing cable, which had its own transporter/coiling units to move it. The electricity powered the main drives, eighteen and ten DC electric motors. Some systems in Big Muskie were electro-hydraulic, but the main drives were all electric.〔Extreme Mining Machines, by Keith Haddock, pub by MBI, ISBN 0-7603-0918-3〕 While working, Big Muskie used the equivalent of the power for 27,500 homes, costing tens of thousands of dollars an hour just in power costs and necessitating special agreements with local Ohio power companies to accommodate the extra load. The machine had a crew of 5, and worked around the clock, with special emphasis on night work since the per kilowatt-hour rate was much cheaper. Once it had stripped all the overburden in one area of the pit, it could move itself short distances (usually less than a mile) to another pre-prepared digging position using massive hydraulic walker feet, although due to its 13,500 ton weight it traveled very slowly (, roughly 0.1 mph) and required a carefully graded travelway with a roadbed of heavy wooden beams to avoid sinking into the soil and tipping over or getting stuck. During its 22 years of service, Big Muskie removed more than of overburden, twice the amount of earth moved during the construction of the Panama Canal, uncovering over of Ohio brown coal. 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「Big Muskie」の詳細全文を読む スポンサード リンク
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