A rich massive sulphide deposit is quickly taking shape in the venerable Sudbury mining camp of northern Ontario.
Since discovering the zone last fall,
Mineralization occurs in the complex’s main contact layer and in the underlying footwall rocks of brecciated granodiorite and Sudbury breccia. So far, grades are much higher in the footwall units.
Scout-hole 100 originally alerted Falco to the area’s potential, as previous drill campaigns were carried out some 340-700 metres away. The hole returned 1.89% nickel and 0.71% copper over 0.1 metre, starting at a depth of 1,443 metres, and a chalcopyrite vein in the footwall, at a depth of 1,561 metres, that assayed 0.26% nickel and 20.3% copper over 0.3 metre.
Follow-up borehole geophysics detected off-hole anomalies to the north, south and east, so a hole (100A) was wedged off the original at a depth of 800 metres, resulting in the discovery of better mineralization to the east (T.N.M., Dec. 10/01). Similar results have beem obtained from four additional wedge holes (100B-E) and one of three new surface holes (101-3).
Hole 102 returned the thickest section of mineralization drilled so far in the contact layer — 68.8 metres grading 1.99% nickel, 1.41% copper, 0.73 gram platinum, 0.51 gram palladium and 0.3 gram gold. The intercept began 1,235 metres down-hole and is 204 metres east of the one cut in hole 100A, making it the most easterly stepout to date.
The wedge holes returned between 2 and 18.5 metres (true thickness) grading 1.56-2.1% nickel and 0.45-0.98% copper. Platinum, palladium and gold each averaged less than a gram over the reported intervals.
In the footwall rocks, holes 100B, 100D and 100E returned between 46.8 and 49.4 metres of sulphides. Nickel values ranged from 2.82% to 4.55%; copper, from 3.53% to 13.63%; platinum, from 3.05 to 9.22 grams; palladium, from 3.26 to 11.94 grams; and gold, from 1.25 to 8.86 grams.
In addition, hole 100E cut 20.7 metres (at 1,550 metres, which is 37 metres up-hole from the second interval) grading 0.58% nickel, 4.45% copper, 1.44 grams platinum, 1.83 grams palladium and 1.92 grams gold.
Hole 100C and hole 102 each intersected two separate intervals of footwall mineralization, though all four are less than half as thick as those intersected by the other holes. Hole 100C averaged 1.06% nickel, 4.22% copper, 1.39 grams platinum, 1.1 grams palladium and 0.3 gram gold over 14.7 metres (at 1,642 metres) and 0.71% nickel, 1.72% copper, 4.39 grams platinum, 2.68 grams palladium plus 0.57 gram gold over 20.9 metres (at 1,681 metres).
Hole 102 averaged 1.71% nickel plus 1.99% copper over 19.5 metres (at 1,334 metres) and 2.55% nickel plus 4.14% copper over 20.6 metres (at 1,370 metres). Both intervals averaged less than a gram each of the precious metals and are about 175 metres east of hole-100A mineralization, making them the most easterly extentions of the footwall zone.
Results are pending for hole 103, though Falco notes that it bored through two narrow intervals of contact mineralization and 13.6 metres (true width) of footwall mineralization. The intervals represent the most southerly stepouts to corresponding hole-100A mineralization, occuring 197 metres and 138 metres away, respectively.
Hole 101, which was the most northerly stepout, failed to return any significant results. The hole was expected to hit contact mineralization about 244 metres north of hole 100A and footwall mineralization about 140 metres north of that hole.
Mineralization in the contact and footwall layers remains open up-plunge to the northeast and down-plunge to the southwest. Footwall mineralization begins about 1,600 metres below surface.
Falconbridge is already considering the bulk-mining potential of the footwall mineralization, noting that true thicknesses were determined using a cutoff grade applicable to that type of mining method. For instance, hole 100B contains up to 18.9 metres (core length) grading 8.5% nickel, 12.98% copper, 16.3 grams platinum, 17.07 grams palladium and 8.04 grams gold.
Four drill rigs are turning at the Nickel Rim South zone to ensure the preliminary program is completed in June. A resource estimate will follow, to determine the next phase of work.
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