Westmin Myra Falls drilling hits massive sulphides

Recent drilling by Westmin Resources (TSE) at its Myra Falls operation near Campbell River, B.C., returned a massive sulphide intersection in a gap area between the Ridge and H-W zones.

The Myra Falls operation comprises the H-W and Lynx underground mines which produce copper and zinc concentrates with significant gold and silver content. The operation is in its 25th year of production.

Westmin said the discovery falls on the heels of last year’s positive exploration results near existing mine workings which provided for a boost in the project’s overall preliminary reserves.

The discovery hole was drilled in an area that was previously unexplored from surface because of difficult topography. The total intersection was a 39.3-metre (128.9-ft.) core length with the bottom 6.2 metres (20.3 ft.) mostly barren pyrite. Based on visual estimates, the company said the remaining 33.1 metres (108.5 ft.) encountered more than 12% zinc and more than 2% copper. These grade estimates are well above the average grade of reserves currently being mined.

Widespread bornite mineralization was also noted throughout, as were frequent occurrences of visible gold over about 23 metres (75.4 ft.) which the company said indicated “good precious metals content.”

True width of the ore-grade interval is estimated to be at least 23 metres (75.4 ft.), Westmin said, and more likely 28 metres (91.8 ft.). The intersection is also considered significant because it is at an elevation accessible from mine workings, and because the geology is indicative of a bedded deposit within the H-W mine stratigraphy.

Westmin said assays will be available May 9 at its annual meeting of shareholders in Vancouver.

Westmin said in its 1990 annual report that mine exploration and interpretative work last year led to the discovery of additional massive sulphide mineralization at both mines.

At the Lynx mine, this work led to the discovery of additional massive sulphide mineralization east of the West G zone orebodies. Westmin said this new zone of “typical Lynx grade ore” was largely responsible for an approximate 20% increase in Lynx mine reserves in 1990 over 1989 figures.

At the H-W mine, 1990 drilling east of known orebodies resulted in the discovery of a significant new zone of H-W ore-grade massive sulphide mineralization.

Exploration drifting is planned in both mines to provide access for continued drilling to define the extent of these discoveries.

The Lynx and H-W deposits are reported to contain total preliminary reserves of 11.1 million tonnes grading 2.3 grams (0.06 oz.) gold, 33.8 grams (0.9 oz.) silver, 2% copper, 0.3% lead and 4% zinc as of Jan. 1. This represents a net gain for the year of 616,400 tonnes after milling 1.17 million diluted tonnes in 1990.

Minable reserves in early 1991 were reported as 9.97 million tonnes grading 2.1 grams (0.06 oz.) gold, 32 grams (0.9 oz.) silver, 1.8% copper, 0.3% lead and 3.7% zinc.

Westmin said the operating performance at Myra Falls in 1990 was not as good as previous years and a number of changes were made in order to improve productivity and ore grades and reduce operating costs.

As an example, bulk mining methods are replacing mechanized cut-and-fill techniques in the H-W mine. Mill operations were also assessed in order to improve zinc and copper recoveries and concentrate grades.