Adds analyst comment and London dateline, updates prices

By Eric Onstad

LONDON, Aug 6 (Reuters) -Copper prices extended losses on Tuesday as speculators remained pessimistic about global growth and weak demand in China, while zinc slumped after a jump in inventories highlighted oversupply.

Three-month copper on the London Metal Exchange (LME) CMCU3 eased 1% to $8,798 per metric ton by 1000 GMT after dropping 1.8% on Monday and touching a 4-1/2-month low.

LME copper has slumped 21% from a record high of more than $11,100 scaled in May.

Global equity markets rallied on Tuesday after plunging a day earlier, but investors in metals markets were wary. MKTS/GLOB

"There seems to be a bit of steadiness overnight, but I think the market is still pretty fearful of a big slowdown, no growth, and we haven't really seen demand in China," said Robert Montefusco at Sucden Financial.

"There's been a lot of abandonment of long positions, a lot of CTA selling, funds and specs selling," he added, referring to Commodity Trade Advisor (CTA) investment funds that are largely driven by computer programs.

The most-traded September copper contract on the Shanghai Futures Exchange SCFcv1 tumbled to its lowest since March 13, closing down 3% at 70,850 yuan.

Although weak U.S. data last week fuelled worries about a potential recession, expected interest rate cuts could provide support.

Another bright spot is that thepremium to import copper into China SMM-CUYP-CN rose to $48 a ton on Monday, the highest since March 18.

Zinc CMZN3 was the biggest decliner on the LME, easing 2.1% to $2,579.50 after LME data on Tuesday showed that inventories surged by 8% to 247,825 tons, having more than tripled over the past nine months MZNSTX-TOTAL.

LME zinc is also the worst performer on the LME over the past month, shedding 14%.

Analysts expect a market surplus of zinc this year of 19,000 tons, jumping to 229,800 tons in 2025, according to a consensus forecast in a Reuters poll. MET/POLL

Among other metals, LME aluminium CMAL3 edged up 0.2% to $2,255 a ton, lead CMPB3 climbed 1.2% to $1,953.50 after tumbling 4.6% in the previous session, while nickel CMNI3 lost 0.4% to $16,210 and tin CMSN3 dipped 0.1% to $29,450.

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($1 = 7.1478 yuan)

Reporting by Eric Onstad; Additional reporting by Mai Nguyen in Hanoi; Editing by David Holmes

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