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一、美国煤炭工业技术进步的概况 美国煤炭工业于十七世纪已普遍发展,十八世纪初具规模。当时大多为井工开采,人力和畜力挖煤、搬运。露天开采始于十九世纪初期,1877年出现地面用的挖煤铲斗。1905年开始使用轨道式挖掘机。二十世纪中叶基本放下镐和铁锹。60年代机械化装煤水平已达到90％。1950年出现连续采煤机,1974年露天产量开始超过井工产量。二十世纪井工开采技术进步如下表。
First, the United States overview of the technological progress of the coal industry The United States coal industry in the seventeenth century has been the general development of the early eighteenth Century scale. At that time, most of the workmanship was mined, manpower and animal power were dug and transported. Open-pit mining began in the early nineteenth century with a digging bucket for the ground in 1877. 1905 began using track excavators. The middle of the twentieth century basically put a pickaxe and shovel. 60s mechanized coal loading level has reached 90%. Continuous shearer appeared in 1950, open-air production in 1974 began to exceed well production. Twentieth century pit technology improvements in the table below.