Copper mining in the United States the northwest part of the state in the early 1850s, and mining began in 1855. The ore is massive sulfide and disseminated ore in mica schist and gneiss, and amphibole schist and gneiss. The principal ore mineral is chalcopyrite, which occurs with pyrrhotite and pyrite, The mine operated until 1883, then worked sporadically until large-scale mining began in 1957. The mine closed for good in 1962. Total production was 31,000 tonnes of copper, 9,400 ounces of gold, and 145,000 ounces of silver. Copper was mined at Creta from 1965 to about 1975. The ore 2% to 4.5% copper as chalcocite
Ore condition with "u", "v" not zero divisors. In this case, Ore's theorem guarantees the existence of an over-ring called the (right or left) classical ring of quotients. Commutative domains are automatically Ore domains, since for nonzero "a" and "b", "ab" is nonzero in . Right Noetherian domains, such as right principal ideal domains, are also known to be right Ore domains. Even more generally, Alfred Goldie proved that a domain "R" is right Ore if and only if "R" has finite uniform dimension. It is also true that right Bézout domains are right Ore. A subdomain of a division ring which