Canadian junior company NGEx Resources reported the results of a positive preliminary economic assessment (PEA) of its 60% owned Los Helados copper project in the Atacama Region of northern Chile. Pan Pacific Copper, operator of the nearby Caserones copper mine holds a 40% contributing interest in the project.

The proposed project would utilize block caving mining methods. The PEA considers both a 65,000-mt/d scenario and a 130,000-mt/d scenario. In both cases, the cave has a single lift and the main mine access is through a 4.3-km decline. Both options have 1,000-m-long main intake and exhaust ventilation shafts (total of four shafts). A 13-km-long conveyor belt tunnel connects the mine to the surface process plant main stockpile.

Production at the 130,000 mt/y mining rate would average 115,000 mt/y of copper, 133,000 oz/y of gold, and 675,000 oz/y of silver in concentrate over a 26-year mine life.

The flowsheet selected for Los Helados includes primary crushing, secondary cone crushing, SAG milling and conventional sulphide flotation. Metallurgical test work indicates production of a high-grade copper concentrate, with high copper and gold recoveries.

Initial capital expenditures are estimated at $3.1 billion for the 65,000-mt/d option and $4.3 billion for the 130,000-mt/d option.