Underground delineation drilling by
Reserves in the High Grade zone now stand at 1.5 million tonnes grading 46.97 grams gold per tonne, according to Watts Griffis & McOuat. The recalculation is based on a gold price of US$300 per oz., 22% external dilution and the cutting of higher grades to 10, 5 or 2 oz. (a historical practice in this section of the Red Lake camp). Also, unlike the estimate of December 1998, the new one contains material in the proven category — 21% of the total contained ounces; the remainder is classified as probable.
In 1948, Red Lake became the tenth of 19 mines to pop up in this renowned camp, and subsequently operated nonstop until labour unrest forced its closure in 1996. Since then, Goldcorp has been proving up the High Grade zone, which lies below old workings, and attempting to resolve the strike (T.N.M., Jan. 13/2000), while constructing new surface facilities and revamping the underground workings.
Goldcorp recently raised US$20.5 million by selling its Havelock Lime division, increasing to US$40.5 million the combined value of its cash and short-term assets. The new funds are earmarked for the mine.
Unlike historically exploited material, the High Grade zone is relatively sulphide-free. Forty percent of the gold is expected to fall out in a gravity circuit, with another 43% recovered by conventional carbon-in-pulp methods. The leftover refractory tailings will be floated and stockpiled on surface.
Preproduction ore development will begin in April and should provide 40,000 tons by the end of the summer. By year-end, Goldcorp expects to have produced 64,000 oz. Full production thereafter is pegged at 240,000 oz., with average cash costs expected to ring in at US$88 per oz.
The latest drill campaign was highlighted by holes 794 and 795, which confirmed the down-plunge extension of the HW5 lens. The former pierced 5 metres of 598.56 grams (uncut), and the latter, 4.6 metres of 286.15 grams. Farther downhole, hole 94 intersected 6.28 metres of the HWA lens, which graded 37.82 grams gold.
The remaining 22 holes were drilled to help determine the zone’s overall geometry, grade and nature of mineralization. Selected results include the following:
– hole 095 — 1.4 metres of 656.3 grams (uncut) and 4.39 metres of 8.61 grams;
– hole 778 — 1.3 metres of 183.4 grams, among others;
– hole 717 — 10.5 metres of 55.37 grams, among others;
– hole 718 — 3 metres of 162.14 grams gold, among others.
Half the holes returned two or more intervals, with the shortest overall being 0.3 metre of 14.85 grams, and the longest, 10.5 metres of 55.37 grams. Grades varied widely as well, from 4.01 to 954.38 grams, with several in the multi-ounce range. Such variation is typical of this part of the camp, and, accordingly, the average uncut grade for the new reserve is 7% higher than the previous estimate.
In addition to High Grade, the Red Lake mine still hosts 1.4 million tonnes of sulphide-bearing reserves that average 12.34 grams gold. Pending further studies, that material, along with stockpiled High Grade sulphide concentrates, could be processed at a later date.
Goldcorp notes that both zones already host a combined inferred resource of 855,471 tonnes grading 22.63 grams gold. The resource is split nearly evenly between the two.
Meanwhile, reserves at the Wharf open-pit mine in South Dakota now stand at 26 million tonnes grading 1.10 grams. The mine — currently Goldcorp’s sole producer — cranked out 83,135 oz. in the nine months ended Sept. 30, 1999. Total operating costs during that period were US$221 per oz.
The mine also hosts an inferred resource of 2 million tonnes grading 0.99 grams gold.
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