"Volumes have been very slim again. The market is pretty much ranging, but copper deserves to be under pressure from the Asarco news and rising stocks in China," one trader said.
US copper producer Asarco and union representatives signed a tentative deal on Tuesday night and striking workers could return by the end of next week after walking out in early July.
It said it planned to boost copper production to take advantage of record metals prices after it recently cut its 2005 copper output estimate to 150,000 tonnes, down as much as 70,000 tonnes from pre-strike forecasts.
Also weighing on sentiment was confirmation that China will sell 20,000 tonnes of copper from its state reserves next week.
Despite the potential for increased metal availability, the cash to three months spread rose $18 to $188/190 backwardation.
"The market is stuck in ranges. There is no real direction, but there is a growing resignation to higher prices," another trader said.
Aluminium futures were slightly off a 10-year high of $2,040 hit late last week but were seen firmly supported by high energy costs and fund buying.
Three-months ended at $2,016, from $2,011.
Traders said resistance at aluminium was developing at $2,025.
Zinc was at $1,578, down $2 and off an earlier eight-year peak of $1,592.50. The market hit $1,675 in July 1997.
Lead was at $983, up $11, on fund buying after touching $992.50 in the pre-market, its highest level since April.
Nickel was at $11,850/900, down from $12,275, while tin was at $6,200, down $100.