(Reuters) - Copper edged down to a 2-week low and aluminum fell to its lowest in more than a month on Wednesday, as concerns about continued demand weakness offset fresh hopes for pro-growth policies from top metals consumer China. Aluminum fell more than other metals under the weight of comments late on Tuesday by producer Alcoa Inc (AA.N) which reported a third-quarter net loss and slashed its aluminum demand forecast. Base metals prices have suffered this year due to lower-than-expected demand from top consumer China, which has seen a significant slow down in economic growth. Benchmark copper was trading at $8,115 a metric tonne by 1003 GMT, 0.4 percent down from a close of $8,145 on Tuesday. Earlier, the metal used in power and construction hit $8,111, its lowest since Sep. 26. "Copper demand is surprisingly low this year and I expect copper to move sideways in the short term but there will likely be a jump in China's copper imports at the beginning of the next year, before new projects and stimulus measures are approved by the new government," said Eugen Weinberg, a commodity analyst at Commerzbank in Frankfurt. "I believe that China will come back next year and many will be surprised to see how much it will drive demand for all metals due to new economic measures and infrastructure plans." Hopes for new stimulus policies which would boost demand for industrial metals in China, grew in recent weeks, and found some support in Chinese media reports this week. Chinese state-backed media said major insurance firms had boosted their combined stock holdings by more than 10 billion yuan ($1.6 billion) over the last three trading days and would continue to support blue chip stocks and stock markets. Another paper said China was likely to offer incentives to spur vehicle sales in rural. SLASH THE FORECAST Copper prices gained about 10 percent in September, spurred by a third round of quantitative easing in the United States and looser monetary policies in the EU and Japan. The rally however was short-lived. "The investor-driven rally last month could not be sustained without improved demand and some speculators were already seeking to lock in profits at the end of last week," VTB Capital said in a research note. "The actual physical demand side is still slack, with no significant gains in copper spot premiums on the LME or the Shanghai Futures Exchange (SHFE) and inventories nudging higher in the past few weeks. The same can be said of Europe premiums in Rotterdam and Shanghai's physical market." Investors were now waiting for data from China, including September trade figures, third-quarter gross domestic product and industrial output over the coming week. In other metals, aluminum was trading at $2,014 a tonne, down almost 2 percent from a $2,055 close on Tuesday. Earlier it hit a session low of $2,006.25 a tonne, its lowest since Sept 7. Analysts said the fall was fuelled by Alcoa's announcement it had slashed its 2012 aluminum demand growth estimate by 1 percentage point to 6 percent. "Alcoa seems to blame weak Chinese demand for the current development but I see it differently. I think it's not the demand in China which is depressing prices but the developments on the production side," Weinberg said. "Chinese aluminum production increased by about 10 percent in the first 8 months of the year and elsewhere demand only fell by about 2 percent. This is not enough, there is a huge oversupply at the moment." In other metals, tin was at $21,625 from $21,825 while zinc, used to galvanize steel, was at $1,986.50 from $2,007 Tuesday's close. Battery material lead was at $2,211 from $2,251.50 and nickel was at $17,710 from $17,930.

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