METALS-Lead tumbles after stocks surge; copper flat ahead of Fed
* Lead stocks jump by 49,475 T ahead of contract expiry
* Copper pressured by concern over Fed stimulus tapering
* LME copper down 1.3 pct on week, Shanghai off 1.1 pct
* Coming up: U.S. retail sales; 1230 GMT
(Adds details, quotes; previous SINGAPORE)
LONDON, Sept 13 (Reuters) - Lead prices slid to a six-week low on Friday after inventories jumped by nearly 30 percent and copper was steady following recent losses, as investors waited for a decision by U.S. authorities on trimming its monetary stimulus.
The price of lead, mainly used in batteries, fell 1.8 percent on the London Metal Exchange (LME) to a session low of $2,085 per tonne, the weakest since Aug. 1, shortly after LME data showed a massive rise in stocks.
Prices pared losses to $2,095 a tonne, a 1.4 percent decline, by 1030 GMT.
Inventories <0#MPBSTX-LOC> shot up by 49,475 tonnes or 27 percent due to huge arrivals at warehouses in the Dutch port of Vlissingen. It's the biggest ever daily rise in lead stocks, according to LME data stretching back to 1970.
Analysts said the stock arrivals may have been engineered by the holder of a large short futures position in the September contract, which matures next week.
LME data <0#LME-FBR> showed that one party holds a short position comprising more than 40 percent of the total.
A short position holder must either deliver metal when the contract matures or close it out with an opposite purchase.
Copper prices were less active, hovering in a tight range and heading for their third weekly fall out of four.
Investors were wary ahead of next Wednesday's meeting of the U.S. Federal Reserve, expected to mark the start of paring back on its $85 billion per month economic stimulus, which has boosted liquidity and helped support commodity prices.
Many analysts and investors expect the Fed to announce an initial curb of $10-20 billion in bond buying.
"We think it's more likely to be $10 billion, with a shift in focus towards buying back more mortgage-backed securities to give further support to the housing market, which would clearly be quite positive for both equities and commodities," said Wiktor Bielski, head of commodity research at VTB Capital.
LME copper was unchanged at $7,060 a tonne after hitting a session low of $7,046.50. The contract slid to a low of $7,025 on Thursday, its weakest since Aug. 8.
The metal is down 1.3 percent for the week so far.
But the industrial metal held above $7,000 a tonne, a level it has only briefly broken below this year, on expectations demand from top consumer China and elsewhere in the world would pick up as the global economy regains footing.
Matt Fusarelli, an analyst at consultancy AME Group in Sydney, sees copper at around $7,190 per tonne in the fourth quarter, supported by a global economy on the mend.
"Better economic conditions in the second half of the year for China should support demand. But also we're expecting a lot more demand coming out of markets like North America and even Europe but that's a bit further down the track, probably first quarter next year," he said.
The most-traded December copper contract on the Shanghai Futures Exchange fell 0.7 percent to close at 51,290 yuan ($8,400) a tonne. It dropped 1.1 percent for the week, its fourth decline in a row.
Investors are also keeping an eye on the global supply situation.
A strike that began last week at the small Salvador copper mine in Chile and owned by Codelco shows no signs of ending as the union has threatened more radical action after what it said was a lack of engagement from the company.
There is however unlikely to be any adverse impact on global flows. Salvador produced 62,700 tonnes of copper in 2012 - less than 4 percent of the total production of Chile's state-owned Codelco, the world's biggest copper producer.
Three month LME copper
Most active ShFE copper
Three month LME aluminium
Most active ShFE aluminium
Three month LME zinc
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Three month LME lead
Most active ShFE lead
Three month LME nickel
Three month LME tin
($1 = 6.1180 Chinese yuan)
(Additional reporting by Manolo Serapio Jr; editing by James Jukwey)