decade of the 1950s began with the opening of electrolytic refining
at the Garfield refinery. This process produced copper cathodes, gold
bars, silver bars, and commercial-grade selenium (used in electronic
devices). By 1958 construction began on a third mine rail haulage tunnel.
For decades the Utah Copper railroad held the record for the highest
traffic density and greatest tonnage hauled of any industrial railroad
in the world. Kennecott purchased ASARCO's Garfield smelter in 1959.
expanded its power plant in 1960 to a 175,000-kilowatt capacity. By
1961 Kennecott's copper mines included four large open pits in the western
United States and one underground mine in Chile. In addition to those
in Utah, operations existed in New Mexico, Arizona, and Nevada. In 1963
the company began a four-year, $100,000,000 expansion of operations.
Parts of this program led to the 1965 opening of a cone precipitate
plant at Bingham, and the Bonneville concentrator and a molybdenum oxide
production plant at the Garfield smelter in 1966.
expansion led to the demise of the town of Bingham, which ceased to
exist in 1971. Later in that decade, the town of Lark also succumbed
to mine expansion. In 1977 construction began at the Garfield smelter
to comply with the Clean Air Act. By 1978 the 1,215-foot smokestack
at the smelter was completed. The smelter ultimately captured 94 percent
of the sulfur contained in the copper concentrates.