Base metals end lower

Industrial metals extended their session losses after the close on Tuesday and copper sank to a near two-week low as fears about the Chinese economic outlook and disappointing results from major aluminium producer Alcoa dampened sentiment. Zinc and nickel plunged to their lowest levels in about three weeks and lead sank to its lowest since December 30 in the late sell-off.
Benchmark copper for March delivery on the New York Mercantile Exchange's COMEX division shed 9.15 cents, or 2.66 percent, to close at $3.3495 per lb. In after-hours trade, the losses extended down to $3.3265, another low dating back to December 30. On the London Metal Exchange (LME), copper for three-month delivery closed down $112.50 at $7,455 a tonne. After the close, prices of the metal used extensively in construction and electronics fell to a near two-week low at $7,320.
Analysts said the catalyst behind the sell-off was news that China raised the proportion of deposits that banks must hold in reserve - another sign that the metal-consuming giant has started to tighten monetary policy. "The general concern in the market is of monetary tightening and the impact that could have on the speed of the global economic recovery, and therefore on the potential for metals consumption recovery," said Gayle Berry, an analyst at Barclays Capital.
Alcoa Inc, one of the world's largest aluminium producers, posted a narrower quarterly loss on Monday, but the results fell short of expectations. The company said although aluminium prices were climbing, demand from some customers, especially plane makers and the commercial construction sector, was not expected to improve soon. In the face of persistently weak demand, rising global stockpiles are a major concern among investors. Chile's mining minister warned on Monday that copper prices could fall as inventories climb.
Copper stocks rose 1,975 tonnes to 517,175 tonnes, their highest since March 2009, while nickel stocks are at 159,726 tonnes, just below Monday's record high of 159,792 tonnes. LME zinc stocks fell over 2,000 tonnes, but the market shrugged this off after last week's 30 percent rise in Shanghai stocks.
Zinc was at $2,476 a tonne versus $2,573 the day before, while aluminium, where inventories remain close to record highs, was at $2,281 a tonne versus $2,330. Traders said worries about power shortages in China and upbeat assessments on demand from UC Rusal could help ward off a larger decline.
Around 70 percent of the total 4.6 million tonnes of aluminium stocks in LME warehouses are said to be tied up in financing deals. Aluminium cancelled warrants - material earmarked for delivery - stood at 244,700 tonnes, equivalent to 18 percent of the remaining 30 percent.
"Although there does appear to be an improvement in physical demand, it also appears that the overall availability of material still remains tight, with metal tied up in warehousing deals continuing to cloud the wider demand picture," Standard Bank said of aluminium in a note.
Nickel was at $17,700 a tonne from $17,890 a tonne, while lead was at $2,432 a tonne from $2,532 a tonne. Tin ended the kerb last quoted at $17,895/17,900 a tonne, after hitting a 17-month high of $18,350 a tonne. In late electronic trade it fell as low as $17,640.