Chile has the world’s largest copper reserves, and is the largest producer and exporter of the metal.Notable copper mines include Chuquicamata and Escondida. Chile accounts for five percent of the Western Hemisphere’s gold production, of which 41 percent is a by-product of copper extraction. The country holds the largest world reserves of rhenium and potassium nitrate, and its reserves of molybdenum are estimated to be the third-largest in the world. Most of Chile’s mineral resources are in the north; gas, coal and oil reserves, in the southern Magallanes Region, are sufficient for local needs. Guarello Island, in the Magallanes Region, has the world’s southernmost limestone mine.