US MIDDAY: copper firmer on covered short positions

COMEX copper prices firmed at the open on Thursday then slipped, as some players saw higher London prices and covered short positions after Wednesday's late rally and others grabbed small profits when continued buying failed to materialise, brokers said.
"There's really no buying right now. Just some locals and a few speculators tossing it around. The open interest is very low. The funds are staying out for the most part. They came in as a buyer on Monday, but that was it," said one floor broker.
Active July copper fell 0.70 cent to $1.2350 a lb. The range was $1.2340 to $1.2540 per lb.
Spot May advanced 0.35 to $1.2500, in a $1.2500 to $1.2550 per lb. range. The rest were either untraded after the first hour or up 0.30 to 1.20 cent.