* Cash/threes zinc spread jumps to $97/T backwardation
* Global aluminium output rises to 5.4 mln T in Oct-IAI
* Nickel hits lowest in more than 11 months
(Updates with closing prices)By Eric OnstadLONDON, Nov 20 (Reuters) - Copper prices slipped on Tuesdayafter five days of gains, unnerved by a sell-off on sharemarkets and sapped by uncertainty before a meeting of U.S. andChinese leaders.Both copper and zinc were in the red despite signs ofshortages developing of physical metal, said analyst NicholasSnowdon at Deutsche Bank in London."It's difficult to see past the major macro events. Thosewill continue to be the key drivers, such as the build-up to theG20 and waiting for signals in terms of where U.S.-China tradenegotiations will head," he said.U.S. President Donald Trump is expected to meet ChinesePresident Xi Jinping on the sidelines of the two-day G20 summitin Argentina, which begins on Nov. 30."But when you look at trends in the refined copper market,particularly ex-China, and the on-shore Chinese refined marketfor zinc, there are some clear signs of tightness, which islimiting the arguments for being short of either of thosemetals," Snowdon added.
Also weighing on base metals was risk-off sentiment as worldstock markets fell in a tech-led sell-off, while the dollarindex rallied from a two-week low, making commoditiespriced in the greenback more expensive for buyers using othercurrencies.Three-month copper on the London Metal Exchange shed1.2 percent to $6,184 a tonne in closing open outcry activityafter rising about 4 percent over the previous five sessions.
* ZINC SPREADS: The premium of LME cash zinc over the
three-month contract soared to $97 a tonne by Monday'sclose, the highest since at least June 2009, the earliest datefor which data is available. It was quoted at $85 on Tuesday.This is due to shortages of metal for immediate delivery asinvestors with short positions seek to close out or roll overtheir contracts ahead of the November expiry on Wednesday. LME three-month zinc fell 1.9 percent to end at$2,551 a tonne.
* ALUMINIUM STOCKS: LME on-warrant aluminium inventories,those not earmarked for delivery, rose by 14,800 tonnes to785,875 , daily LME data showed, and have surgedby 30 percent since early October.LME aluminium added 0.3 percent to finish at $1,940a tonne.ALUMINIUM OUTPUT: Global primary aluminium output rose to5.414 million tonnes in October from 5.301 million tonnes inSeptember, data showed. NICKEL TECHNICALS: Nickel fell 0.8 percent to end at $11,095 a tonne, the lowest since Dec. 14 last year.
"The correction looks poised to persist towards themulti-month down channels supports at $11,040," St?(C)phanie Aymes,head of technical analysis at Societe Generale, said in a note.PRICES: Lead gave up 2.1 percent to close at $1,961a tonne and tin lost 1 percent to $19,400.<^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^Top Base and Precious Metals Analysis - GFMS ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^> (Reporting by Eric Onstad; Editing by John Stonestreet andEmelia Sithole-Matarise)
Reuters Messaging: eric.onstad.thomsonreuters.com@reuters.net))