US copper futures extended the previous session's retreat from 4-1/2 week highs at the open on Tuesday after sluggish housing data for the month of May reinforced concerns of a US economic slowdown, brokers said.
"I think the housing numbers and the lack of performance put in yesterday, where we were up 8.00 or 9.00 cents before giving it all back by the close, is keeping things a bit on edge," said one New York-based metals broker. "I think you had a lot of people that were caught in there and at this point are probably being very cautious," he said.
By 10:34 am EDT (1434 GMT), most-active September copper was off 2.75 cents at $3.3925 a lb on the New York Mercantile Exchange's COMEX division, moving in a relatively quiet band between $3.3620 and $3.4190.
Soon-to-be spot July copper fell 3.25 cents to $3.3855, near the bottom of its early $3.36-$3.4185 trading range. Copper futures trading volumes were estimated at 7,460 lots by 10:00 am. On Monday, a rally in copper, which is used in construction and electrical wiring, was undermined after the index of the National Association of Homebuilders (NAHB) fell to its lowest level in more than 16 years.
Subcontract workers at Chile's Codelco plan to meet in general assembly on Thursday to give the final go-ahead to a strike across the five divisions of the world's largest copper producer, a spokesman said Tuesday. Stalled contract talks at Chile's Collahuasi, one of the world's largest copper mines, and threatening strike action at Southern Copper Corp's two copper mines and a smelter in Peru offered additional support.