* Premium for cash over 3-month copper reverses to adiscount
* Eyes on surveys of China's manufacturing sector (Updates prices, adds dollar impact)By Pratima DesaiLONDON, Sept 28 (Reuters) - Copper prices firmed on Mondayas expectations of robust demand from top consumer Chinasupported sentiment, but doubts about longer-term prospects anda jump in London Metal Exchange stocks capped gains.Benchmark copper on the LME was up 0.5% at $6,578 atonne at 1603 GMT. Prices of the metal, used widely in the powerand construction industries, are down more than 4% since hittinga 27-month high at $6,877.50 last week.The rally was based on the massive Chinese fiscal stimulusin recent months, which boosted economic activity and industrialmetals demand after the novel coronavirus lockdowns."Chinese demand is still rising, but not at the pace it was,there will be resistance to higher prices," said Julius Baeranalyst Carsten Menke."Stimulus in China pulled demand forward, it did notgenerate additional demand. It is difficult for China to startlarge infrastructure projects which have a big impact on theeconomy because most of them have been done."
DATA: September surveys of purchasing managers in China'smanufacturing sector, particularly the new and export ordercomponents, due on Wednesday will be scrutinised for clues todemand growth for industrial metals. DOLLAR: Support for metals came from a lower U.S. currency,which makes dollar-priced commodities cheaper for holders ofother currencies, and that could boost demand. UNITED STATES: Democrats in the U.S. House ofRepresentatives are working on a $2.2 trillion stimulus packagethat could be voted on this week. Talks on the package hadstalled for nearly two months. INVENTORIES: Stocks of copper in LMEregistered warehouses jumped 29,500 tonnes to 103,125 tonnes andcancelled warrants -- metal already earmarked for delivery --slipped to 41% from near 60% last week.This has eased concerns about a tight LME market and thepremium for the cash over the three-month contract hasreversed into a discount.OTHER METALS: Aluminium was up 1.6% at $1,777 atonne, zinc gained 2.6% to $2,431, lead added0.5% to $1,844, tin rose 1% to $17,355 and nickel climbed 1.7% to $14,510. (Reporting by Pratima Desai; editing by EmeliaSithole-Matarise/David Evans/Ken Ferris)