Open bidding for the Las Bambas copper project in Peru is set to begin July 2, one week later than originally planned.

More than a dozen companies, including Anglo American Plc., Cambior Inc., Cia. Vale do Rio Doce SA, Phelps Dodge Corp., Rio Tinto Ltd., Southern Peru Copper Corp. and Teck Cominco Ltd., have pre-qualified to participate in the auction.

The Agencia de Promocion de la Inversion Privada Paseo de la Republica (ProInversion) is overseeing the privatization process.

News reports attributed the change in dates to negotiations with officials from the Apurimac region, where the mine is located, but information on ProInversion's Web site, as well as a source involved in the process, indicated that agreements with local officials had already been established.

Estimated proven reserves at Las Bambas are 40.5 million tons with grades exceeding 2-percent copper. Additional exploration could delineate a deposit of more than 500 million tons containing both copper and gold. Initial investment is estimated at $700 million to $1.4 billion.