Oct. 8 (Bloomberg) -- Copper prices rose the most in six weeks as the sagging dollar and upbeat economic data boosted speculation that demand for the metal used in pipes and wires will climb.

The dollar fell to the lowest level in almost 14 months against a basket of six major currencies. The number of Americans filing first-time claims for unemployment benefits dropped last week to the lowest level since January, U.S. government data showed today. Copper prices have doubled in 2009 after demand in the first half of the year increased in China.

“Copper is taking off with the weaker dollar and some renewed economic optimism,” said Donald Selkin, the chief market strategist at National Securities Corp. in New York. “The jobs numbers gave the market a boost.”

Copper futures for December delivery climbed 11.9 cents, or 4.3 percent, to $2.8985 a pound on the Comex division of the New York Mercantile Exchange, the biggest gain for a most-active contract since Aug. 21.

Supply concerns also bolstered copper, said Daniel Major, an analyst at RBS Global Banking & Markets in London.

BHP Billiton Ltd., the world’s largest miner, may take two weeks to investigate an accident at its Olympic Dam mine in Australia that forced the closing of the main hauling shaft. The company is still producing ore at Olympic Dam.

Chilean Mine

BHP also faces a potential strike at its Spence copper mine in Chile, where workers agreed to delay a walkout and extend wage talks to give the company time to revise a contract offer, a union official said yesterday. Employees will walk out on Oct. 13 should BHP refuse to improve its latest proposal, said Francisco Aravena, a union spokesman.

The strike “is unlikely to have a significant impact on supply-demand dynamics in the near term,” Major of RBS said.

More than 20 percent of copper-mine output is “at risk” over the next three to six months because of labor contract talks, Barclays Capital said yesterday.

Copper for delivery in three months rose 3.9 percent to $6,330 a metric ton ($2.87 a pound) on the London Metal Exchange.

Aluminum, nickel, tin, lead and zinc prices also rose in London.

To contact the reporter on this story: Anna Stablum in London at astablum@bloomberg.net; Millie Munshi in New York at mmunshi@bloomberg.net.

Last Updated: October 8, 2009 15:26 EDT