Copper futures slumped on worries about economic growth following disappointing economic data in China and Japan.
Most-active copper for September delivery recently was down 14.05 cents, or 4.5%, weaker at $2.9490 per pound on the Comex division of the New York Mercantile Exchange. The nearby July contract slid 13.45 cents, or 4.4%, to $2.9370.
Concerns about China, the world's largest consumer of copper, were fanned after the Conference Board revised its leading economic indicator for China to a gain of 0.3% for April, compared to the previously reported 1.7% rise.
Adding to worries about the health of the global economy, Japan reported that industrial production slipped 0.1% in May, while household spending fell 0.7%.
"There are still a lot of doubts about how strong the economy will get," said Stephen Platt, an analyst with Archer Financial Services in Chicago.
Still, there are some supportive factors that are keeping copper from declining further, he said. Inventories stored in London Metal Exchange warehouses keep declining, falling another 1,225 metric tons Tuesday to 451,950. Also, canceled warrants, which are earmarked for delivery, continue to rise.
