Protests against copper mines in Peru have stalled about US$400 million in copper exports since July 18, Reuters reported Aug. 9, citing Gabriel Monge, manager of port operator Terminal Internacional del Sur.

Freeport-McMoRan Inc.'s Cerro Verde, MMG Ltd.'s Las Bambas, Glencore PLC's Antapaccay and Hudbay Minerals Inc.'s Constancia have been unable to ship copper concentrates from Matarani to Asia and Europe, the report said.

The four operations combined for about 1.2 million tonnes, representing about half of Peru's total copper output.

Strikes launched by residents in the southern region of Arequipa were sparked by Peru's construction permit grant for Southern Copper Corp.'s US$1.4 billion Tia Maria copper project. The protests have resulted in blockades affecting roads and a minerals railroad.

According to Pablo de la Flor, manager of the National Society of Mining, Petroleum and Energy, production at the four mines have continued and are stockpiling concentrates on site for later shipment.

However, the mines — said to be in "critical" condition — may be forced to halt operations should they fail to secure supplies shipped through Matarani in the near term.

MMG's Vice President for Corporate Affairs, Domingo Drago, said in the Reuters report that the Las Bambas operation is exhausting its fuel supply and may halt output in about a week. However, Drago expects the situation to normalize "very soon," noting that the mine can stockpile concentrates for about two months before running out of space.