US copper futures fell more than 3 percent at the open on Tuesday, rattled by worries over inflation and slowing economic growth after comments from Federal Reserve Chairman Ben Bernanke left the door open for another US interest rate hike this month, sources said.
By 10:23 am EDT (1423 GMT), copper for July delivery slipped 11.10 cents, or 3.08 percent, at $3.49 a lb. on the New York Mercantile Exchange's COMEX division, near the bottom of its early $3.44-$3.589 trading band. Spot June was off 13.10 cents, or 3.5 percent, at $3.56, moving between $3.5450 and $3.6680.