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Southern Copper says Peru plant to be partially suspended 3-5 days

(Recasts with comment from Southern Copper on Monday)

LIMA, Feb 11 (Reuters) - Southern Copper Corp said on Monday that a key plant it uses to produce copper in Peru would not fully restart for another three to five days while work is done on its tailings and railway infrastructure following heavy rains.

Peru's environmental regulator OEFA has been investigating a potential tailings spill at Southern Copper's Cuajone mine, after being alerted by local residents of a "greenish solution" that started streaming into a nearby river.

Southern Copper, one of the world's largest copper producers, said there was no tailings spill.

The company said its operations, though, were being "seriously affected" by a recent bout of intense rains in Peru's southern copper belt. There has been flooding at some of its installations, and a search effort is underway to find a worker swept away by a massive mudslide while helping clear debris from a ravine, Southern Copper said.

The company, controlled by Grupo Mexico, said it suspended operations at its copper ore concentrator as a precaution during a downpour at its Cuajone mine on Friday.

The concentrator would not be fully restarted until the company finishes repairs and upgrades on a railway and the tunnel used to dispose of tailings, work that is estimated to take three to five days to complete, it said late on Monday.

"The concentrator ... will start operations following repairs," Souther Copper said in a statement.

A spokesman for the company said the concentrator at its Toquepala mine had also been suspended due to rains, and that both concentrators were already starting to process some ore and that tailings were being stockpiled to be disposed of later.

The company said in its statement that its Toquepala and Cuajone mines were operating at about 60-70 percent of capacity and that its Ilo smelter was at 70 percent.

Southern Copper's troubles in Peru, the world's No.2 copper miner, come as mine operations around the world are facing increased scrutiny following the deadly collapse of Vale SA's tailings dam in Brazil last month.

Southern Copper said in a statement late on Sunday that its tailings dam at Cuajone was stable.

The company has been trying to improve relations with local residents in southern Peru for years in hopes of reviving its $1.4 billion Tia Maria mine, which has been delayed for nearly a decade due to protests by farmers and activists concerned with its potential environmental impact.

Heavy rains and mudslides in Peru have killed at least five people and left hundreds without homes in the past week, according to authorities. (Reporting By Marco Aquino and Mitra Taj; Editing by Nick Zieminski and Tom Hogue)