U.S. assistance to foreign copper producers and the effects on domestic industries and environmental standards [electronic resource] : hearing before the Subcommittee on Mining, Forest Management, and Bonneville Power Administration of the Committee on Interior and Insular Affairs, House of Representatives, Ninety-eighth Congress, first session, on U.S. assistance to foreign copper producers and the effects on domestic industries and environmental standards, hearing held in Tucson, Ariz, May 20, 1983.