* IMF/EU loan talks for Ireland likely concluded early Dec. * Market cautious ahead of U.S. holiday * Chile's Collahuasi says 220 workers abandon strike (Recasts, updates dateline/prices, pvs SINGAPORE) By Rebekah Curtis LONDON, Nov 25 (Reuters) - Copper rose in volatile trade on Thursday, supported by persistent supply concerns and a bout of upbeat U.S data, but gains were capped by worries about the potential of sovereign debt problems spreading in the euro zone. Copper for three-months delivery on the London Metal Exchange traded at $8,275 a tonne at 1116 GMT from Wednesday's last bid of $8,250 a tonne. Supportive for base metals was upbeat data from the United States on Wednesday, showing a two-year low in new jobless claims and improving consumer spending, which hinted that the world's largest economy was nearing a self-sustaining recovery. But industrial metal markets were cautious as traders were reluctant to make big bets ahead of the U.S. Thanksgiving holiday. "I expect choppy trade and I expect that to occur up until Christmas," said Carl Firman, analyst at Virtual Metals, citing sovereign debt problems in the euro zone. "On the supply side the copper market appears very tight," he added. "That is very bullish for copper." The premium for cash copper over the three-month contract hit $41, its highest since October 2008, with a trader saying short positions for the December contract scrambled to find material. Investors were edgy, with the euro near a two-month low as the euro zone debt crisis showed little signs of abating, with fears of contagion still high after Ireland unveiled an ambitious austerity plan. "Ireland hasn't quite panned out the way people were anticipating that it would," said Charles Kernot, an analyst at Evolution Securities. "People are still worried." Talks on an IMF/EU loan for Ireland will likely be concluded by the start of next month, an EU spokesman said, after the debt-stricken country on Sunday agreed to an international rescue. "The debt reduction plan and promised spending cuts are encouraging, but political tensions are still running high and there is no guarantee that the public will be happy with these measures," said Andrey Kryuchenkov, an analyst at VTB Capital. "There is a good chance Lisbon will have to walk the same path as Ireland and Greece, seeking financial aid as its borrowing costs soar," he added. CHINA EYED Meanwhile, investors are worried that that demand from top metals consumer China, may soften, as it battles to stem inflation. China on Friday raised cash reserve requirement for banks, the second such move in a fortnight, stepping up its battle to tame inflation by locking up cash. China might have to raise inflation targets for next year, even as it is campaigning to reassure people that price pressures will remain in check. Despite this, many analysts are confident that Chinese demand for copper will remain robust into next year. On the supply side, the world's No. 3 copper mine, Chile's Collahuasi, said on Thursday 220 workers have abandoned a 21-day strike so far to take its latest wage offer, still short of the 777 it needs to end the walkout. "The ongoing dispute at the Collahuasi mine in Chile is starting to raise supply concerns," investment bank Fairfax said in a note. Among other base metals, aluminium traded at $2,273 from a close of $2,259 a tonne on Wednesday. Zinc was at $2,136 a tonne from $2,122 a tonne and battery material lead was at $2,245 a tonne from $2,222 a tonne. Tin traded at $24,225 a tonne from $24,300 a tonne and nickel was at $22,780 a tonne from $22,500 a tonne. The metal hit a session high of $22,789 a tonne, its highest since Nov.15.

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