* Aluminium cancelled warrants jump by 25,000 T in Detroit * Labour talks continue at Vale's Canadian nickel ops * Coming up: US ADP jobs at 1215 GMT, Chicago PMI, US factory orders By Melanie Burton LONDON, Aug 31 (Reuters) - Copper rose on Wednesday, underpinned by a weaker dollar and supply concerns, but was on track to post its worst month in more than a year given lingering uncertainty shrouding the global economic outlook for demand. Three-month copper on the London Metal Exchange traded at $9,225 a tonne in official rings, up 0.70 percent from a close of $9,160. It earlier hit $9,245, a peak since early August when the metal succumbed to heavy liquidation on fears a global slowdown would eat into demand. It is on track to close down 6 percent for August, its worst month since May 2010. A weaker dollar was helping support the complex, analyst David Wilson of Societe Generale said, but gains were not backed by strong fundamentals. "People are nervous at restocking because of the macro outlook which is not improving -- if anything it's getting worse," analyst David Wilson at Societe Generale said. "Production issues are becoming a side show -- This is a last hurrah before this heads to the downside." The euro rose to a session high against the dollar on Wednesday after a German government spokesman said the cabinet had approved a framework for draft law to expand the euro zone rescue mechanism. A weaker dollar makes commodities less expensive for holders of other currencies. Since the price differential between Shanghai and London copper became unfavourable for imports last week, purchases from top consumer China have tailed off. Premiums for bonded copper in Shanghai have fallen more than 10 percent from last week due to poor arbitrage and reduced demand for spot metal in the domestic market, marking the first fall in premium since July, traders said on Wednesday. Still, supply concerns were providing a major plank of support, according to Macquarie Securities. "The current high price reflects very low inventory cover and the expectation that the market will remain in deficit between supply and demand for some time yet," Macquarie securities said in a note. "Data from the world's largest copper producer, Chile, highlights the supply issues." Copper output in the world's No. 1 producer totalled 373,498 tonnes in July, down 18 percent from the same month last year, according to a government report this week. Elsewhere, a string of U.S. economic data today includes the ADP and Challenger jobs reports, which will be closely watched ahead of August non-farm payrolls on Friday, as well as Chicago Purchasing Manufacturers Index and July Factory orders. "This week's global PMIs are...important as the metals sector is very much in need of positive impetus from the economy," Credit Suisse said in a note. NICKEL TALKS In nickel, labour talks appear to be going smoothly at Vale's Thompson mining, smelting and refining complex in Manitoba, Canada where the current contract expires in mid-September. "Talks continue in Thompson and we remain committed to reaching a deal," a Vale spokesman told Reuters. Thompson has the capacity to produce around 60,000 tonnes a year of refined nickel, according to Reuters Metal Production Database. Nickel traded at $22,075 a tonne, up from a close of 21,950 on Tuesday.

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