Westmin expects another reserve boost at Fortuna

Ongoing drilling by Westmin Resources (WMI-T) is expected to boost reserves at the company’s wholly owned Fortuna de Cobre copper project in Chile.

Westmin says the latest results indicate that the Fortuna deposit is larger than originally thought. A recent hole returned 462 metres grading 0.34% copper in an area previously thought to be of lower grade and partially outside the proposed pit boundary. The hole bottomed in 32 metres grading 0.896% copper. Another hole in the current program returned 78 metres of 1.09% copper at a depth of 424 metres and extended the enrichment blanket an additional 100 metres to the east. Westmin also noted that several other holes returned mineralization outside of the pit boundary.

Fortuna is an advanced oxide-sulphide copper project undergoing extensive drilling and metallurgical testwork, in preparation for a feasibility study that is scheduled for completion in early 1999.

At last report, Fortuna contained proven, probable and possible reserves totalling 592 million tonnes grading 0.27% copper. This calculation is based on 83 drill holes, including 23 from the current program.

Westmin notes that these reserves exhibit a fair degree of grade variability, including a high-grade, mixed sulphide-oxide copper enrichment blanket beneath the core-area oxides at a depth of 370 to 500 metres. Deep drilling is continuing to define the extent of the enrichment blanket and the upper part of the underlying primary sulphide mineralization.

Westmin says the predominant copper oxide mineral at Fortuna is chalcanthite, which dissolves in water without the addition of acid. As a result, portions of the deposit have excellent leach characteristics and low acid consumption, compared with most other oxide copper projects.

Fortuna is near Westmin’s Lomas Bayas copper mine project, now being developed as an solvent-extraction electrowinning (SX-EW) operation. Startup at Lomas Bayas is scheduled for June of this year.