ASARCO LLC is a mining, smelting, and refining company based in Tucson, Arizona, USA, that mines and processes primarily copper. The company is a subsidiary of Grupo México.
Its three largest open-pit mines are the Mission, Silver Bell and the Ray mines in Arizona. Its mines produce 350 to 400 million pounds of copper a year. Asarco conducts solvent extraction and electrowinning at the Ray and Silver Bell mines in Pima County, Arizona and Pinal County, Arizona and a smelter in Hayden, Arizona. Before its smelting plant in El Paso, Texas was suspended in 1999 it was producing 1 billion pounds of anodes each year. Refining at the mines as well as at a copper refinery in Amarillo, Texas produce 375 million pounds of refined copper each year.
Asarco's hourly workers are primarily represented by the United Steelworkers.
Asarco has 20 superfund sites across the United States, and it is subject to considerable litigation over pollution.