LIMA, March 31 (Reuters) - Workers at Freeport McMoRan Inc's Cerro Verde mine in Peru, one of the country's biggest copper deposits, plan to go on a 48-hour strike starting April 8 for unspecified reasons, the union said in a statement on Thursday.

Freeport has a 53.56 percent stake in the mine, which produced about 32,000 tonnes of copper in January. Sumitomo Metal Mining Company Ltd controls 21 percent and Peruvian miner Buenaventura owns 19.58 percent.

(Reporting by Teresa Cespedes; Editing by Sandra Maler)