Copper ended down by less than half a percent on Monday, limited in its range by concerns over stalled US debt deal talks and escalating supply troubles at the world's largest copper mine. Copper's weakness spread across the broader base metal complex, as the prospects of a failed budget deal and potential ratings downgrade in the United States drove money into safer havens such as the Swiss franc and gold.
The lone exception was aluminium, which fed on bouts of technical buying to hit its highest since June 15, at $2,624 a tonne. In New York, the key September COMEX contract eased 0.35 cent to settle at $4.4065 per lb. Trading volumes stagnated on Monday as markets awaited the results of a deadline for US lawmakers to sort out a debt ceiling plan. A little more than 30,500 lots traded in New York, down about 36 percent from the 30-day norm, according to preliminary data from Thomson Reuters.