METALS-Potential supply disruptions fuel copper's rise to 3-week high

* Premium for cash tin over 3-month jumps

* LME/ShFE arb: (Adds closing prices)

LONDON, May 2 (Reuters) - Copper prices hit a three-week high on Tuesday due to concerns about supply disruptions in Indonesia, but caution over slowing demand in top consumer China capped gains.

Benchmark copper on the London Metal Exchange, untraded in the rings, ended up 1.2 percent at $5,735.50 a tonne from an earlier $5,820 a tonne, its highest since April 10.

“The news about the strike in Indonesia at Grasberg has lifted prices,” said Julius Baer analyst Carsten Menke, adding that slowing activity in China’s manufacturing sector, a major source of demand for industrial metals, was a negative.

GRASBERG: Thousands of workers from the Indonesian unit of Freeport McMoRan Inc staged a rally near the Grasberg copper mine on Monday, protesting against layoffs by the miner due to a contract dispute with the government.

CHINA: China’s factory sector lost momentum in April, with growth slowing to its weakest pace in seven months as domestic and export demand faltered and commodity prices fell, a private survey showed on Tuesday.

LEAD: The price of lead was slightly weaker at $2,248 a tonne, but supported by worries about supplies on the LME market.

LEAD STOCKS: Latest data shows lead stocks in LME approved warehouses up 4,150 to 169,425 tonnes MPBSTX-TOTAL, but that total is still 10 percent below the level at the end of March.

LEAD WARRANTS: Cancelled warrants -- material earmarked for delivery and so not available to the market -- account for nearly half of total inventories. Traders are also watching a large position holding between 30 and 39 percent of warrants.

LEAD SPREADS: The premium, or backwardation, for cash metal over the three-month contract rose to $34.50 a tonne on Friday, its highest since late January MPB0-3.

LEAD DEMAND: “On the demand side, offtake remains strong on both sides of the Atlantic, with only limited signs of seasonal weakness,” INTL FCStone analyst Edward Meir said. “European battery demand is particularly good on account of strong vehicle sales. However, the Chinese market does not look as inspiring.”

TIN SPREADS: The premium for cash tin over the three-month rose to $90 a tonne MSN0-3 on Friday, its highest since March 21 as traders fretted about shortages on the LME market. Three-month tin rose 0.3 percent to $19,960 compared with an earlier $20,085, its highest since April 12.

TIN STOCKS: Inventories of tin in LME warehouses at 2,865 tonnes are less than half the 5,995 recorded on Feb. 16 and account for less than one percent of global consumption estimated at around 350,000 tonnes this year.

PRICES: Aluminium was up 0.9 percent at $1,929.50 and zinc added 1.2 percent to $2,655. Nickel was ended 0.7 percent higher at $9,515 a tonne.


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