Alvaro Ossio, the mine's vice president of finances, said Las Bambas, Peru's largest copper minefield, had declared "partial" force majeure with contractors and was evaluating doing the same for copper sales.

"The plant is still operating with the stock we have, which is limited and will only give us a few more days of production," Ossio said. If the blockade continued then "probably in less than a week it would clearly paralyze all production," he added.

The potential freeze on operations comes amid wider protests that have hampered a number of mines in Peru's southern copper belt. The country is the world's second largest producer of the metal, which is also the main driver of its economy.

MMG said on Thursday that operations at Las Bambas would be affected by road disruption with supplies being blocked by anti-mining protests. The roadblocks have disrupted logistics at the site since Sept. 22.

The unrest has affected shipments from four mines that produce about half of Peru's copper - Freeport-McMoRan Inc's Cerro Verde, Las Bambas, Glencore PLC Antapaccay and Hudbay Mineral's Constancia.

Las Bambas, which accounts for 16% of Peru's entire copper output, had targeted between 385,000 tonnes and 405,000 tonnes of copper production this year, versus 385,000 tonnes in 2018.

(Reporting by Marco Aquino; Writing by Adam Jourdan; Editing by Richard Chang and Bill Berkrot)

By Marco Aquino