The environmental impact study was submitted to the government agency for approval in June 2002.

Gaby, a copper oxides deposit located just south of Codelco's Chuquicamata mine in northern Chile, would produce 170,000 tonnes of copper cathodes per year starting in 2005, according to Codelco in a text published last June on the environmental agency's Web site.

"The project would initiate its production at the beginning of 2005 after a 19-month period of construction," Codelco said. "The initial investment is estimated to be $600 million and the project would have a life of 13 years," it added.

However, Codelco Executive President Juan Villarzu told reporters recently the company has not yet made a decision on when to begin construction of Gaby. He said the board would decide in May or June of this year.

Even though Gaby is near the Codelco Norte district - comprised of Chuquicamata, Radomiro Tomic and several other undeveloped ore deposits in northern Chile - it will be classified as a separate business unit.

Gaby holds proven mineral reserves of 541 million tonnes, with an average copper grade of 0.44 percent.

The mine would be an open-pit operation using SX-EW technology to produce cathodes for export, Codelco said.