However, gains were rolled back in after-hours trading following a speech by Federal Reserve Chairman Ben Bernanke, who failed to detail any possible steps from the central bank to boost the sputtering economy. At the Economic Club of Minnesota Bernanke said the central bank would spare no effort to boost disappointingly weak growth and lower unemployment but offered no details of steps monetary policymakers might take.
"Copper prices are feeling a bit cramped here, not getting any further ideas of stimulus coming from the Fed. With Bernanke staying on message, it does not give copper much impetus to go up," said Sterling Smith, an analyst for Country Hedging Inc. in St. Paul, Minnesota.
London Metal Exchange (LME) benchmark copper closed at $9,115 from a last bid $9,092 per tonne on Wednesday. After Bernanke's comments, it dipped back down toward the $9,100 level in after-hours trade.
In New York, the key December COMEX contract rose 1.15 cents to settle at $4.1435 per lb, after dealing between $4.0865 and $4.1595. After the close, prices dipped into negative territory before holding near the $4.13 level.
The day began with softer-than-expected US data showing new jobless claims unexpectedly rose last week, which pulled industrial metals and equities lower. President Barack Obama later on Thursday is due to lay out a major jobs package.
"It's following the stock market ... there has been a very close correlation between the two for weeks now," said Donald Selkin, chief market strategist with National Securities Corp. in New York.
Prices managed to overcome initial losses after another report showed a much narrower trade deficit for July. The trade data lessened the blow of the weekly jobless claims figure by offering some hope for growth in the third quarter.
"The narrowing of the trade deficit should revise GDP a little bit," National Securities Corp's Selkin said.
A two-day pay strike by workers at Peru's third-biggest copper mine Cerro Verde increased worries about supply constraints.
Adding to supply-side worries, Freeport's Indonesia mine workers are set to strike from Sept. 15 to Oct. 15 unless the company meets pay demands.
NICKEL SUPPLY
Indonesia's industry ministry said the country may impose a tax or quota on mineral ore exports ahead of a planned regulation to ban all exports of raw minerals by 2014. This will squeeze supplies of metals, including nickel, and support prices., said Credit Suisse analyst Stefan Graber.
"Nickel demand has actually surprised on the upside and (stainless) steel production has been more resilient than expected. We are now at a price level where nickel pig iron producers are less competitive," he said.
Also pointing to improved demand for the metal, inventories of nickel in LME-approved warehouses fell to their lowest since February 2009 at 99,180 tonnes, compared with a record high at more than 166,000 tonnes hit in Feb 2010.
Nickel rose $275 to close at $21,050 a tonne.
Copyright Reuters, 2011