Refco Inc analyst Dan Horn said that copper needed some new fundamental development to help sentiment as market-moving news was scarce. "The market just kind of dipped," he said.

The July contract expired at 81.75 cents a lb, down 0.55 cent and traded from 81.60 to 83.20 cents. "Longer-term fundamentals are very positive and they point to an oversold market, but shorter-term, we need something to push traders to buy," said Horn.

He pegged near-term support at 81 cents a lb and upside resistance at 83 cents.