Freeport McMoRan shuts sole U.S. copper smelter after fire

(New throughout, adds details and company comment)

Nov 13 (Reuters) - Freeport McMoRan Inc has temporarily shut its sole U.S. copper smelter after a fire broke out as molten copper breached a processing vessel in the Arizona facility and flowed onto the ground, a spokesman said on Thursday.

The company is investigating the cause of the accident, which occurred Wednesday night, and extent of the damage after the breaching of the electric arc furnace, which melts concentrate before copper is extracted, a spokesman said in an email.

Until that is complete, the duration of the shutdown and impact on the production from the smelter are uncertain, he said.

There were no injuries and the material was contained and is no longer flowing, the spokesman said in an earlier statement.

The copper flowed inside and around the west side of the smelter building, part of the mining operation some 90 miles east of Phoenix (LSE: PHNX.L - news) . The accident set some infrastructure on fire.

The smelter has capacity to produce 180,000 tonnes per year, about 14 percent of annual U.S. output. North American annual consumption of copper, used to make electrical wire and tubing, is about 2.3 million tonnes.

The closure did not have an immediate impact on premiums (CU-PREM), which are under pressure. U.S. demand remains relatively sluggish with the construction industry recovering slowly, and consumption is also slowing in China, the world's top end user.

For now, Freeport may be able to make up for any shortfall from a relatively short shutdown, traders said. Its other smelter, Atlantic Copper, is in Spain.

Still, the accident comes as traders report that Rio Tinto (Xetra: 855018 - news) 's Kennecott copper plant in Utah, the country's No. 2 smelter, is operating at below capacity due to lower ore grades from its nearby mine.

Freeport expects to sell about 1.8 million tonnes of copper this year, it said in a recent earnings report.

The concentrate processed at Miami is almost exclusively sourced from Freeport's copper mines in Arizona and New Mexico, the spokesman said. (Reporting by Susan Taylor in Toronto and Josephine Mason in New York; Editing by Leslie Adler and David Gregorio)