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Native copper nugget from glacial drift, Ontonagon County, Michigan. An example of the raw material worked by the people of the Old Copper Complex. The Old Copper complex or Old Copper culture is an archaeological culture from the Archaic period of North America's Great Lakes region. Artifacts from some of these sites have been dated from 6500 ...
The United States is a net exporter of copper ore and copper concentrate. In 2015, out of 1.25 million metric tons of recoverable copper metal extracted from mines, 320,000 tons of copper were exported in the form of ore and concentrate, to be smelted and refined elsewhere.
The metal would have been found in nature without the need for smelting, and shaped into the desired form using hot and cold hammering without chemical alteration or alloying. As of 1999, "no one has found evidence that points to the use of melting, smelting and casting in prehistoric eastern North America." [3] (p 136)
Copper bells, axe heads and ornaments from various parts of Chiapas (1200–1500) on display at the Regional Museum in Tuxtla Gutierrez, Chiapas.. The emergence of metallurgy in pre-Columbian Mesoamerica occurred relatively late in the region's history, with distinctive works of metal apparent in West Mexico by roughly 800 CE, and perhaps as early as 600 CE. [1]
A number of copper mines also contained a notable amount of silver, both in native form and naturally alloyed with the copper. Halfbreed is the term for an ore sample that contains the pure copper and pure silver in the same piece of rock; it is only found in the native copper deposits of the Upper Peninsula of Michigan. [2]
Copper(II) ions migrate through the electrolyte to the cathode. At the cathode (reduction reaction), Cu 2+ ions are reduced in copper metal and Cu (s) plates out, but less noble constituents such as arsenic and zinc remain in solution unless a higher voltage is used. [53] The reactions involving metallic copper and Cu 2+ ions at the electrodes ...
44% of mining facilities in the United States are located in forests. Large-scale mining in areas of Latin America, like Brazil, release pollutants detrimental to neighboring rainforests. [38] Copper mining efforts in the Carajas Mineral Province in Brazil result in 6,100 km of deforestation every year. [38]
Native copper is an uncombined form of copper that occurs as a natural mineral. Copper is one of the few metallic elements to occur in native form, although it most commonly occurs in oxidized states and mixed with other elements. Native copper was an important ore of copper in historic times and was used by pre-historic peoples.