The smelter at Superior, completed in 1924, and the surrounding roaster, furnaces and converter operated for nearly half a century before the Magma Copper Co. closed them in 1971.

Local business owners in Superior, Arizona say a major copper mining project could revitalize the area's economy.

Asarco upgraded the Hayden smelter to meet U.S. air-pollution rules as part of a 2015 settlement with the ... Eight of Arizona’s top 10 ranked releases in 2018 came from copper mines and smelters.