Geology of Mauritania ore. A Neoproterozoic carbonate unit, part of a synformal nappe overturned in the Paleozoic, now forms a major copper deposit 250 kilometers northeast of Nouakchott in the Mauritanides Belt. The one kilometer, 250 meter wide deposit spans the West and East Moghrein Guelb hills. Forty meters below the deposit is a secondary deposit of cuprite, azurite, malachite and tenorite, with an additional 2.25% copper, some gold and sulfide mineralization including cubanite, chalcopyrite, pyrrohitite and aresnopyrite. In the 2000s, mining at the site had mostly ceased except for gold mining in the tailings pile. Gypsum is extracted from the N'Drahamcha quarry,
Ore condition condition ensures "R" is an essential submodule of "D". Lastly, there is even an example of a domain in a division ring which satisfies "neither" Ore condition (see examples below). Another natural question is: "When is a subring of a division ring right Ore?" One characterization is that a subring "R" of a division ring "D" is a right Ore domain if and only if "D" is a flat left "R"-module . A different, stronger version of the Ore conditions is usually given for the case where "R" is not a domain, namely that there should be a common multiple