(Adds comments from representatives of MMG and local mining association)
LIMA, Aug 8 (Reuters) - Anti-mining protests in Peru have held up about $400 million in copper exports from some of the country's top mines and blocked supplies from reaching their operations for nearly three weeks, the manager of port operator Tisur said on Thursday.
Four copper mines - Freeport-McMoRan Inc's Cerro Verde deposit, MMG Ltd's Las Bambas, Glencore PLC's Antapaccay and Hudbay Mineral's Constancia - have been unable to ship copper concentrates from Matarani to destinations in Asia and Europe since July 18, said Gabriel Monge, manager of port operator Terminal Internacional del Sur (Tisur).
Last year, the four mines - led by the country's top producer, Cerro Verde - churned out about 1.2 million tonnes, or about half of total copper output from Peru, the world's No. 2 supplier.
Residents of Peru's southern copper belt have occupied roads and a minerals railroad to protest a construction license the government gave to Southern Copper Corp for its $1.4 billion Tia Maria project, which has been delayed for nearly a decade due to local opposition from farmers. nL2N24Q12I
So far, Cerro Verde, Las Bambas, Antapaccay and Constancia have continued producing and are stockpiling concentrates on site for shipment later, said Pablo de la Flor, manager of the National Society of Mining, Petroleum and Energy.
But the four are in "critical" condition and could be forced to suspend operations if they cannot get supplies from Matarani soon, de la Flor added.
Las Bambas is running out of fuel and could stop producing in about a week if the situation continues, MMG's vice president for corporate affairs, Domingo Drago, said by phone.
But Drago said he expects the situation to normalize "very soon." Las Bambas can stockpile copper concentrates for about two months before it runs out of space, he added.
Freeport-McMoRan and Hudbay did not immediately respond to requests for comment.
Glencore declined to comment.
(Reporting By Marco Aquino and Mitra Taj; Editing by Dan Grebler)