2012 U.S. copper production at highest level in 3 years – U.S.G.S. 9 avril 2013 Mining Partager Copper cathode produced by Boss Mining in Katanga – DR Congo (MNM Pic) U.S. smelter copper output last year declined to its lowest level since before World War II, the U.S. Geological Survey reported. RENO (MINEWEB) –