Results from a second phase of drilling by
Situated near Thunder Bay, Ont., Lac des les consists of a 2,400-tonne-per-day flotation mill fed by adjacent pits. Concentrates are trucked to Sudbury for custom-smelting and then to Norway for refining.
Mining began in late 1993. However, profitability was hampered by dilution and the negative effect of forward sales programs at lower-than-spot prices. Despite having overcome these problems in 1998, Lac des les pushed the company $5.4 million into the red in the first half of this year (T.N.M., Sept. 6/99).
A reversal now appears to be on the horizon, following the initiation of an independent feasibility study aimed at expanding production. The study follows 49,900 metres of drilling completed over the past six months. Results of the final phase of this program are now available.
Twenty-eight of the 33 holes drilled returned potentially economic grades and widths of mineralization. All were aimed at three targets:
- a brecciated gabbro on the western and southern flanks of the producing Roby zone;
- a high-grade pyroxenite below the current pit, at between 224 and 519 metres; and
- a gabbronorite extending downdip from the North Roby zone.
The best results came from the high-grade pyroxenite, particularly in hole 151, which averaged 5.69 grams palladium per tonne over 121.49 metres (from 576 to 697.5 metres, or 165 metres of true width). The highest value, however, came from hole 155, which graded 13.47 grams over a 16.9-metre section of a 93-metre interval that averaged 5.1 grams.
High-grade mineralization has now been intersected to 518 metres below surface, where it remains open. Mineralization dips to the east.
Southwest of the Roby pit, hole 150 intersected 310.83 metres of mineralized breccia grading 1.41 grams palladium. The breccia unit is known to measure 366 metres at its widest.
Results from holes aimed at the gabbronorite unit include 4.08 grams palladium over 11.9 metres true-width (107-122 metres down-hole) in hole 13 and 1.78 grams over 57.9 metres true-width (164-228 metres) in hole 106.
Collared east of the South Roby pit, hole 171 extended mineralization in that direction. The hole hit 96.19 metres (53.8-149 metres) grading 2.33 grams palladium.
Minor platinum, gold, copper and nickel are present in all the holes reported.
In August, measured and indicated resources were upped to 38.8 million tonnes grading 2.4 grams palladium per tonne, plus 0.21 gram platinum, 0.21 gram gold, 0.075% copper and 0.092% nickel. This includes material already blocked out for mining, representing a nearly 200% increase over the estimate reported in early 1998, but excludes the current holes plus the final 34 holes of the first phase.
H.A. Simons is expected to finish the feasibility study by year-end. A scoping study earlier this year evaluated the potential for a 9,000-tonne-per-day operation. However, any increase in production would depend on the amount of reserves estimated, plus available financing and governmental approval.
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