LIMA -(Dow Jones)- Freeport-McMoRan Copper & Gold Inc. (FCX) said Wednesday that production of copper and molybdenum at majority owned Sociedad Minera Cerro Verde SA (CVERDEC1.VL) in southern Peru hasn't been materially impacted by the strike that started Wednesday.

The company said talks aimed at ending the strike continue.

"Production of copper and molybdenum concentrates have not been materially affected by the strike that began this morning," Freeport-McMoRan's Copper & Gold's Director of External Communications Eric Kinneberg said in an email.

"We will continue negotiating a new labor contract to replace the one that expired on Aug. 31, 2011," he said.

Unionized workers at Cerro Verde started an indefinite strike Wednesday to seek higher pay.

Workers at Cerro Verde held a 48-hour strike last week to demand higher wages. The company said that work stoppage did not affect production.

Cerro Verde is one of Peru's biggest copper miners. In the second quarter of this year, it turned out 170 million pounds of copper, compared to 166 million pounds in the same period last year.

Cerro Verde is majority-controlled by Freeport-McMoRan Copper & Gold. Compania de Minas Buenaventura SA (BVN, BUENAVC1.VL) and a subsidiary of Sumitomo Corp. (SSUMY, 8053.TO) also have stakes in the company.

Peru is the world's second biggest copper producer.