* Codelco mulls seeking mediation to head off strike
* Altonorte smelter strike, coincides with maintenance
* Supply threats help boost copper above 15-month peak (Updates with fresh Codelco comment, details)
By Alonso Soto
CHUQUICAMATA MINE, Chile, Dec 29 (Reuters) - Workers voted on Tuesday to strike over pay at Chile's giant Chuquicamata copper mine, fanning supply fears that boosted global prices for the red metal, while tough-talking world No.1 producer Codelco said it was mulling mediation.
The strike vote at Chuquicamata, which produces around 4
percent of the world's copper concentrate and is one of the
world's biggest copper mines, came after union workers on
Monday began an indefinite strike at Chile's Altonorte smelter,
where owner Xstrata
The strike call also comes just weeks ahead of a Jan. 17 presidential election run-off, and analysts have warned Chile could face more mine union strife if center-right front-runner Sebastian Pinera, who wants to sell up to 20 percent of Codelco [CODEL.UL], is elected. [ID:nN07158519]
Union leaders, who had expected workers to accept Codelco's wage offer, said unionized workers who make up the bulk of the deposit's workforce had voted to reject the wage deal by a very slim margin.
If the strike goes ahead at the Chuquicamata complex, which had been on course to produce 565,000 tonnes of copper this year, it would be the most serious by Codelco's unionized workers since 1996.
A Codelco official in the northern city of Calama said the state copper giant was still analyzing whether to seek five days of government mediation in a bid to head off the planned strike, but said the company would use "all appropriate mechanisms".
"The issue is being evaluated," the official told reporters. "We have no alternative now but to prepare to face a bitter period in the history of Chuquicamata and Codelco," he said.
Copper rose nearly 3 percent on Tuesday on the London Metal
Exchange to its highest in more than 15 months on the back of
the looming strike. Copper for three-months delivery
Strikes and stoppage threats have buffeted Chile this year as workers sought a bigger slice of windfall profits after copper prices rebounded from the global financial crisis.
"The workers have voted to strike," said Victor Galleguillos, head of one of the three unions that negotiated jointly with Codelco. "If the company does not ask for mediation, the strike would begin on Dec. 31."
Some workers scuffled with union officials after the vote, spraying water and chanting "Together, Chuqui will never be conquered".
A strike at Chuquicamata, which marks the last major stoppage risk at Codelco for nearly a year, would inflict production losses just as the company is set to break years of dwindling output in 2009 thanks to an aggressive investment plan to upgrade older mines like Chuquicamata. [ID:nN23247277]
A top Codelco official said earlier on Tuesday the company was prepared to face any strike and had enough stocks to meet delivery commitments.
If the company opts for mediation, and fails to clinch a deal with workers, a strike would likely begin in early January.
CODELCO BRACED FOR STRIKE
Codelco is one of the Chilean state's main earners, and the government has used billions of dollars in windfall copper savings to battle Chile's first recession in a decade amid the global financial crisis.
Rising copper prices, which have more than doubled this year, have emboldened mine workers across the globe to demand more benefits from mining companies.
The workers' rejection of the wage offer underscores rank and file disenchantment with their union leaders. However, while a strike at Chuquicamata would be a major setback for Codelco, it doesn't face another round of major collective wage negotiations until late 2010.
"The market will sit up and watch. But price action will be blurred by moves in the dollar, the LME catch-up over the holidays and closing positions ahead of the year end," said Mark Pervan, senior commodities analyst at ANZ.
"Historically these strikes are not protracted events. I think we could see a resolution early next year," he added.
A prolonged strike at Altonorte could delay some anode shipments and force mining companies to sell concentrate to other smelters, though analysts expect any short-term market impact to be minimal.
For data on global smelter output please see: http://bond.views.session.rservices.com/Metals/
Altonorte's 274 union workers, representing about 90 percent of the labor force in charge of production, downed tools at the complex, which produced 232,000 tonnes of copper anodes last year, and blocked access roads.
Workers accuse Xstrata of deliberately timing the general maintenance, which is carried out every 2- years and is due to end on Jan. 20, to undermine their strike.
Workers blocked access roads to the plant for a second day on Tuesday in a bid to pressure the company after workers rejected the company's last wage offer.
"The only thing the company has told us is there's no money, that miners can strike for a month (if they like)," said Abdiel Sepulveda, head of Altonorte's union No. 1. "We are not letting anyone in. There's no way they can be producing anything."
Company officials were not immediately available for comment. (Additional reporting by Nick Trevethan in Singapore; Writing by Simon Gardner; Editing by Marguerita Choy)