The USGS assessed undiscovered copper in two deposit types that account for about 80 percent of the world's copper supply. Porphyry copper deposits account for about 60 percent of the world's copper. In porphyry copper deposits, copper ore minerals are disseminated in igneous intrusions. Sediment-hostedstratabound copper deposits, in which copper is concentrated in layers in sedimentary rocks, account for about 20 percent of the world's identified copper resources. Globally, mines in these two deposit types produce about 12 million tons of copper per year.
Copper plays two key roles in energy production. First, it helps with incorporation of iron into red blood cells, preventing anemia. Second, it is involved with generation of energy from carbohydrates inside of cells.