Copper prices fell on Wednesday as investors remained cautious ahead of a key European Central Bank meeting that could provide more clues on its tapering decision, Mining News reported.
The dollar hovered near a one-week high against major currencies, boosted by rising US Treasury yields and a weaker euro, remaining cautious ahead of Thursday's European Central Bank debate on cutting stimulus.
A stronger dollar makes metals priced in dollars more expensive and thus less attractive to holders of other currencies.
Copper for December delivery fell 1.2% from Tuesday's settlement to $4.230 a pound ($9,306 a ton) on the Comex market in New York.
Copper prices have been losing momentum since last week as data showed factory activity in key parts of Europe and Asia slowed in August.
In China, manufacturing contracted for the first time in nearly a year and a half.
The State Reserve Administration also put 150,000 tonnes of copper, aluminium and zinc on the market, causing copper prices to cool.
Chile's export
Chile's copper exports surged 40.5% in August from a year earlier as global prices remained high, the country's central bank said Tuesday.
Total copper exports jumped to $4.383 billion last month, accounting for more than half of the country's total exports, from $7.822 billion in August.
Chile reported a trade surplus of $6m and imports also surged 73 per cent in August to $7.81bn, the bank said.
