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Harper's Encyclopedia of United States History (ed. Benson Lossing) 2 0 Browse Search
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Harper's Encyclopedia of United States History (ed. Benson Lossing), Copper. (search)
ences that copper-mines were worked in the United States by the Mound-builders (q. v.). The first mines worked systematically were chiefly in New Jersey and Connecticut. From 1709 until the middle of the eighteenth century, a mine at Simsbury, Conn., yielded much ore, when, for about sixty years, the mine was a State prison. The Lake Superior copper-mines (the most considerable in the world) were first worked, in modern times, in 1845, when traces of ancient mining were found near the Ontonagon River. The Jesuit missionaries had noticed copper ore in that region as early as the middle of the seventeenth century. In making excavations in 1848, a mass of copper, supported upon blocks of wood, with charred wood under it, was found 20 feet below the surface. When taken out it weighed 8 tons. The output of copper in the United States during the calendar year 1899 amounted to 585,342,124 pounds, valued at $104,190,898. In that and the following year the output at the famous Calumet an