Copper slipped on Wednesday, as rising inventories underlined a weak demand picture, but a force majeure at BHP Billiton reinforced some concerns about supply.
Three-month copper on the London Metal Exchange was at $6 393.5 (R47 312) a tonne by 11:53 SA time compared to Tuesday's close of $6 416. The metal ended down $49 in the previous session.
Latest data showed copper stocks, which have been rising since mid-July, climbed 5 275 tonnes to 362 550 tonnes, their highest in more than five months.
But analysts said supply concerns were capping losses after BHP Billiton declared force majeure at its Olympic Dam mine in Australia, the world's number 4 copper mine.
"There have been a host of production losses over the past few months. They are starting to rack up now," said Gayle Berry, an analyst at Barclays Capital.
"Even though we've got LME inventories that are still rising, the concerns on the production side are going to help to provide support to prices, if not push them higher," she said.
Copper, used in power and construction, was lifted on Tuesday by a strike at Chile's Spence copper mine.
The Olympic Dam incident is expected to result in the loss of 70,000 tonnes of copper and 1,500 tonnes of uranium, said analyst Kieran Daly at Investec Securities in South Africa.
Investors were unimpressed by BHP's first 2009/10 forecast for a 5 to 10 percent rise in production at its Escondida copper mine in Chile, which they saw as modest, and by the fall in its quarterly copper output.
CHINA DISHES DATA
The market awaited a big serving of Chinese data on Thursday, including gross domestic product, industrial output, consumer prices and urban investment figures for more clues on the economic strength of the major base metals consumer.
