LIMA, Peru, Oct 20, 2011 (Dow Jones) -- Peruvian copper producer Sociedad Minera Cerro Verde SA's (CVERDEC1.VL) production of copper and molybdenum concentrates remains mainly unaffected by the strike that began Sept. 29, a company official said.

"Cerro Verde is focusing its operations on essential functions to supply ore to the leach pad and concentrator," Freeport-McMoRan Copper & Gold Inc. (FCX) Director of External Communications Eric E. Kinneberg said in an email message. Freeport-McMoRan has a majority stake in Cerro Verde.

"As a result, production of copper and molybdenum concentrates has not been materially affected by the strike that began on September 29," he added.

The company said, "Mining rates are averaging approximately 200,000 metric tons per day (which is approximately two thirds of normal production rates), essentially all dedicated to the production of ore to feed the concentrator and the leach pad which are both operating at near capacity levels."

The company says that it is operating the facility with about 600 supervisory and other personnel who volunteered to work under strike conditions.

The company said that downtime at the concentrator is associated with routine maintenance and unrelated to the strike activities.

The workers put down tools in September to back demand for higher wages and other benefits.

Cerro Verde produced 170 million pounds of copper in the second quarter of this year, up from 166 million pounds in the same period in 2010. Compania de Minas Buenaventura SAA (BVN, BUENAVC1.VL) and a subsidiary of Sumitomo Corp. (SSUMY, 8053.TO) also have an interest in the company.