(Updates with closing prices)By Peter HobsonLONDON, July 30 (Reuters) - Copper prices fell on Monday asinvestors shrugged off a potential strike at the world's largestcopper mine and focused instead on economic data this weekexpected to show slowing growth in top metals consumer China.Benchmark copper on the London Metal Exchange (LME) closed down 0.8 percent at $6,250 a tonne while the most tradedcontract on the Shanghai Futures Exchange fell 1.4percent.
Concerns over the impact of trade tensions on metals demandwere still driving the market after helping to push copper downaround 15 percent on the LME since early June, said ING analystOliver Nugent.
"You had a couple of stable days last week and then themarket started (on Monday) with a wave of profit taking out ofChina, restoring the downward sentiment," he said.
CHILE STRIKE: Workers at Chile's Escondida copper minerejected a final contract offer and began a vote on strikeaction that will end in the middle of this week. Last year, a44-day strike at the mine pushed copper prices sharply higher. CHINA DEMAND: Fears of supply interruptions were matched byworries of weaker demand in China, where factory sector growthis expected to have slowed for a second month in July. Theofficial PMI survey is due on Tuesday and the private Caixinmanufacturing PMI on Aug. 1. POSITIONING: Investors are betting that copper prices willcontinue to fall, with the net short position on the Comexexchange the largest in nearly two years. ZINC: Benchmark LME zinc finished down 1.5 percentat $2,557 a tonne. It has fallen almost 30 percent sinceFebruary and is near a one-year low of $2,473.85 hit on July 20.TECHNICALS: Zinc was holding just above support at the 50percent retracement of its two year rally from 2016 to early2018 and its 2017 low of $2,427.50.
ZINC SPREAD: The premium of cash zinc over the three monthcontract has surged to $60.25, the highest sinceOctober, suggesting a shortage in nearby supply.
COPPER/ZINC STOCKS: While copper and zinc stocks inLME-registered warehouses were fairly stable in July, stockpilesin Shanghai Futures Exchange storehouses fell, with copper down25 percent at 197,068 tonnes and zinc down 50 percent at 48,135tonnes.WARRANTS: Underlining concerns of tight supply, one entityheld 50-79 percent of LME copper warrants and one entitycontrolled 50-79 percent of LME zinc warrants. OTHER METALS: Aluminium ended up 1.1 percent at$2,094 a tonne, lead closed 0.4 percent higher at$2,153, tin gained 0.5 percent to $20,025 and nickel finished unchanged at $13,860 a tonne.
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