Quadra sizes up Sierra Gorda

Vancouver — Development at Quadra Mining‘s (QUA-T) Sierra Gorda copper project in northern Chile is at an advanced stage.

The program began in April 2004, since which time Quadra has spent $2.6 million on exploration, including 50 reverse-circulation drill holes (10,712 metres), geophysical surveys, mapping, and geological modelling.

Including drilling by previous operators, the project has now been tested by 129 core holes (47,664 metres) and 160 RC holes (29,015 metres).

A newly released independent resource estimate, compliant with National Instrument 43-101, was calculated using both the company’s work and that of previous operators. Sierra Gorda now hosts an indicated sulphide resource of about 215 million tonnes grading 0.38% copper and 0.066% molybdenum, as well as an inferred sulphide resource of 182 million tonnes grading 0.34% copper and 0.024% moly. The project also hosts an indicated oxide resource of 181 million tonnes grading 0.37% copper, based on a 0.2% copper cutoff grade (moly is not recoverable from oxide material), and an inferred oxide resource of 36 million tonnes averaging 0.29% copper, using the same cutoff grade. The oxide resource includes supergene copper, which could be processed with oxide or hypogene sulphide resources.

The copper oxide mineralization continues from near the surface to depths ranging from 150 to 200 metres below the surface. As a result, future development will likely involve initial leaching of copper oxides followed by conventional flotation to treat the underlying sulphides.

Moly mineralization is strongest at the oxide-sulphide interface, which suggests potential for extraction of copper-moly sulphide mineralization early in a sulphide mine plan.

The project is within 2 km of a main highway and rail line connecting Antofagasta and Calama.

Quadra will carry out a US$3.8-million work program this year. A 15,000-metre RC drill program is under way in an attempt to expand oxide resources in defined areas and delineate more copper-oxide targets in five prospective areas.

Meanwhile, Quadra’s Robinson mine in Nevada is expected to produce 146.7 million lbs. copper and 62,000 oz. gold this year at an estimated cash operating cost of US$1.09 per lb. copper. The company intends to install a US$7.7-million molybdenum circuit, which should produce 1.6 million lbs. moly in 2006.