Southern Copper Corporation is an integrated copper producer. It produces copper and, in the production process, obtains several by-products, including molybdenum, silver, zinc, sulfuric acid and other metals. Its segments include the Peruvian operations, the Mexican open-pit copper mines and the Mexican underground mining operations segment identified as the IMMSA unit. The Peruvian operations segment includes the Toquepala and Cuajone mine complexes, and the smelting and refining plants, including a metals plant industrial railroad and port facilities that service both mines. The Mexican open-pit operations segment includes the La Caridad and Buenavista mine complexes, and the smelting and refining plants, including a metals plant and a copper rod plant, and support facilities that service both mines. The Mexican underground mining operations segment includes five underground mines that produce zinc, copper, silver and gold, and a zinc refinery.