US copper futures settled up over 12 percent on Tuesday in a session that featured two trading halts by the New York Mercantile Exchange (Nymex) when prices spiked to maximum daily limits as speculators bought heavily after a one-week shake-out, sources said.
Copper for July delivery settled up 42.40 cents, or 12.2 percent, at $3.8855 a lb, near the upper end of its $3.39-$3.8950 trading band.
At 9:46 am EDT (1346 GMT), Nymex halted Comex copper futures trade for 15 minutes after prices soared to their 20-cent maximum daily limit. A new 40-cent maximum limit was then imposed and reached by 12:06 pm, causing another 15-minute halt.
One Comex floor dealer cited on Monday's technical rebound from a consolidation zone at around $3.25 a lb fuelled a short-covering reversal that carried over into today's trade.
"Yesterday was a very critical settlement in the whole complex. All of the metals were sharply lower, especially on ACCESS, and they turned around and came all the way back up, so that key reversal probably fuelled the buying at the open today," he said.
Spot May copper shot up 43.55 cents, or 12 percent, to close at $4.0755, and had the scope to test the all-time Comex record at $4.16 a lb, set on May 11.
Comex final copper volume was estimated at 16,000 lots compared with 12,159 lots on Monday.