US copper futures ended at a one-week low on Tuesday with softer global equity markets and concerns about a prolonged US housing slump stalling the industrial metal's upward momentum, dealers said.
Copper for December delivery closed down 4.50 cents at $3.6410 per lb on the New York Mercantile Exchange's COMEX division, its lowest settlement since October 9, after dealing in a $3.6020-$3.7085 session range. Traders expected the market to remain rangebound, with a breakout seen above $3.74 or below $3.59.
Just before the close, futures volumes were estimated at 14,078 lots, compared with Monday's final count of 13,030 lots. Open interest in COMEX copper futures increased by 989 lots to 91,033 contracts by October 15.
Comments made by Federal Reserve Chairman Ben Bernanke on Monday night saying the housing slump will likely be a significant drag on US growth into next year weighed on global equity markets, with copper following suit, analysts said.
"For the time being, modest declines in US equity markets should not unhinge the advance in commodities, but if the selling is to pick up steam in a big way, commodities will most likely get swept up in the downdraft," Edward Meir, metals analysts with MF Global said in a daily market comment.
US economic numbers provided no fresh direction for the copper market as the data was largely in line with market expectations. Production by US manufacturing, mining and utilities companies rose 0.1 percent in September as expected, with a brief strike at General Motors pulling production down slightly.
"The data was basically flat. It's certainly not in the copper market. We have had a lot of activity in some of these markets overnight, but in the copper, there is nothing that has been done in the last three weeks that really gives us any idea," said one New York-based futures commission merchant.
On the fundamental front, workers at the second-biggest division of Chilean state copper miner Codelco have accepted a new contract offer from the company, 5-1/2 months ahead of time, the company said Tuesday.
Codelco said some 4,500 workers at the El Teniente division, which operates the world's largest underground copper mine, agreed to the 39-month contract. In industry news, Chilean copper exports rose to $3.109 billion in September from $2.706 billion the previous month, central bank figures showed on Tuesday.
Copper exports in September 2006 were $3.010 billion. London Metal Exchange (LME) copper for delivery in three months settled down 1.4 percent or $115 to $8,035 a tonne from Monday's kerb close.
LME stocks rose by 875 tonnes to 140,525 tonnes on Tuesday - their highest level since May. COMEX copper stock levels were flat at 19,557 short tons on Monday.