COMEX copper for September delivery fell 3.90 cents to settle at $3.3535 per lb, after dealing between $3.3420 and $3.4020 on Monday. COMEX volume stood near 55,000 lots in late New York trade, more than 20 percent above the 30-day norm, according to preliminary Thomson Reuters data.
"There seems to be a general tone of weakness across a number of markets due to some weaker economic data, in particular the disappointing Chinese data," said Gayle Berry, an analyst at Barclays Capital. "There is an underlying expectation that we will see some sort of policy response. Until the market sees this is going to happen or until we get something better on the news front, this kind of weaker tone looks like it's going to stay with the metals in the short term," Berry said.