NEW YORK, Oct 12 (Reuters) - U.S. copper futures rose at the open on Monday, buoyed by further bouts of weakness in the dollar and surrounding strength in the broader metals complex, traders said. For detailed report on global copper markets, click on [MET/L] * Copper for December delivery HGZ9 firmed 2.50 cents to $2.8630 a lb by 10:32 a.m. EDT (1432 GMT) on the New York Mercantile Exchange's COMEX division. * Range from $2.8380 to $2.8770. * Last week, December contract rallied to a three-week high at $2.9010. * COMEX estimated futures volume at 4,299 lots by 9 a.m. * Conditions on the light side as industry insiders gather in London for annual LME week. For a TAKE A LOOK on LME Week, please see [ID:nL8107826] * Dollar-denominated copper up over 1 percent as further losses in the American currency make the metal more attractive to non-U.S. investors. [USD/] * Copper swept up in broader complex strength, with gold futures nearing a new all-time high above $1,060 an ounce - traders. * Copper's morning gains held in check by near-term demand concerns reflected in rising supply base - traders. * London Metal Exchange warehouse stocks climbed 775 tonnes on Monday to a five-month high at 347,375 tonnes. [LME/STX1] * COMEX copper warehouse stocks went up 634 short tons to 55,661 short tons as of Friday. * COMEX net noncommercial short positions trimmed to 4,771 lots in week ended Oct. 6, from 6,281 lots the previous week. Open interest up at 119,080 lots versus 113,874 lots in the week of Sept. 29. [ID:nN0985872] * Market looking ahead to China's preliminary September trade data on Wednesday, expected to show imports of unwrought copper and semi-finished copper products down for the third straight month. [ID:nHKG142718] * On the labor front, workers at Chile's Spence copper mine began a vote Sunday on a contract offer from owner BHP Billiton (BLT.L) (BHP.AX), which could result in a strike next week if rejected. [ID:nN11121207] * LME copper for three-month delivery MCU3 last traded at $6,279 a tonne from a close of $6,230 on Friday. (Reporting by Chris Kelly)

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