The United States foreign trade in copper: 1790-1932

During the first sixty years of its existence the United States imported most of the copper it conusmed. In 1845 Lake Superior mines began to supply the domestic market, but imports did not decline until the Civil War and subsequent tariffs. Exports were relatively large just before the war, then declined and did not expand again until the Montana copper boom of the eighties. There was a fairly close inverse correlation between domestic copper consumption and export, although extraneous incidents frequently obscured the connection. Exports failed to increase after the World War when competition from new foreign producers kept price down. Copper tariffs had been removed before 1895, when imports for smelting and refining began. These imports rose rapidly and were responsabile for an increasing fraction of our export business. In 1929 they exceeded exports for the first time. Tge import balance of 1929-1932 was partly responsabile for excise on imported cooper which, in 1932, ended a 38-years period of free entry for unmanufactured copper.