copper processing | Definition, History, & Facts,
Ores. Principal forms in which copper ores are found include native copper, porphyry copper, massive deposits, and mixed ores. Native copper is simply the metal found unadulterated in nature. Occasionally copper is still found in its native form, but more frequently it is mixed with other minerals, some of which may have value themselves.12.3 Primary Copper Smelting,12.3 Primary Copper Smelting 12.3.1 General1 Copper ore is produced in 13 states. In 1989, Arizona produced 60 percent of the total U. S. ore. Fourteen domestic mines accounted for more than 95 percent of the 1.45 megagrams (Mg)The Mineral Copper - DesertUSA,Ores containing as little as .15% copper can be mined profitably in open-pit mining, but underground mining is profitable only if an ore contains 6% to 7% copper. For many years, Chile has been the world's largest producer of copper, with the United States a close second.