A worker sprays down plates laden with pure copper from an electrolytic process at the Silver Bell mine west of Marana.

Arizona Daily Star 2006

Grupo Mexico, parent of Tucson-based copper producer Asarco LLC, is expected to complete a deal to take full control of the Silver Bell mine west of Marana by acquiring an additional 25 percent ownership stake from a business partner.

A company official told the Mexican news service Agencia Reforma that the estimated value of the acquisition from Tokyo-based Mitsui & Co. is between $115 million and $120 million.

Asarco partnered with Mitsui in 1996 to acquire the mine, which last year produced about 21,500 tons of copper cathode, or about 5 percent of Grupo’s total copper production, the newspaper said.

The Silver Bell Mine, which currently employs more than 175 people, is expected to continue producing until 2031.

Grupo Mexico operates 14 mines in Mexico, Peru and the southwestern United States.