Pio Lake Zone
Located in the southern part of the Hawk Ridge Project, the Pio Lake Zone was discovered in the early 1960s. Pio lake and mine development work was carried out by Falconbridge and its partners until 1974. An adit and drifts were extended for a length of 117 m. Four raises were extended, three of which reached surface where they can be seen as pits on the surface.
The area was drilled extensively in the 1960s and early 1970s but little of the information and none of the core is available. Troymin carried out a short drill program on the zone in 1995 where four drill holes totalled 198.3 m (Figure 12).
In 1973-74 a total of 6437 tonnes of mineralization were mined from underground and open pits from both veins. In the East Vein the remaining resources was estimated at 7260 tonnes grading an average of 6.9% Cu and 0.3% Ni. In the West Vein the remaining resource was estimated at 9662 tonnes grading an average of 6.6% Cu and 3.2% Ni (Lone Star Mining, 1974). No data was included in Lone Star’s report to determine the method used to calculate the resource, and none of the parameters used to calculate the resource were described in the report. This historical resource estimate is on the Hawk Ridge Property but the calculation does not conform to the categories used in NI-43- 101 regulations. There are no more recent resource calculations available on the Pio Lake Zone and since the core is no longer available additional drilling would be required to confirm or update the historical resource calculations. A qualified person has not done sufficient work on to the data to classify this historical estimate of mineral resources, this resource should not be treated as a current mineral resource and should not be relied upon. The historical resource estimate is not being treated as current mineral resources or reserves.
The area is underlain by basalt that has been structurally deformed and overturned into a synclinal fold about 1.5 km wide and 4 km long that plunges gently to the south-southeast. The axis of the fold is located about 275 m to the west and the Pio Lake Zone is on the east limb of the fold. A fault extends for at least 2000 m to the south but appears to be truncated by a later northeast- trending structure about 100 m north of the Pio Lake Zone.
The copper and nickel mineralization is present in two lenses that contain veins of massive, semi-massive and disseminated sulphides in folded and faulted basalt, gabbro and pyroxenite that contain occasional bands of schist. The East Lens is about 2 m wide and has a strike length of 46 m on surface. The West Lens is 3 m wide and extends for 60 m. Both zones strike north-northwest ad dip 60- 85°E. Although the zone was drilled a depth of 100 m the 1995 drilling only tested the zone to a depth of 35 m (Figure 13).
There is a distinct difference in the nature of the mineralization of each lens. The mineralization in the West Lens consists of massive, semi-massive and disseminated pyrrhotite, chalcopyrite and pentlandite in a fault-bounded section. In the East Lens the sulphides are represented by disseminated and laminated chalcopyrite-pyrrhotite mineralization in sheared basalt and sulphide-rich iron formation.
The West Lens contains more massive and banded units and contains distinctly more nickel. The West Lens reported an average of 6.08% Cu, 1.43% Ni, 0.05% Co, 15.0 g/t Ag, 0.4 g/t Pt and 1.1 g/t Pd over 2.82 m from a composite sample in drill hole HR 95-03.
The mineralized zone is a fault-bounded lens of pyrrhotite, chalcopyrite and pentlandite in chloritized basalt flows of the Hellancourt Formation. The basalt is cut by several early thrust faults. The West Lens may be part of a larger magmatic copper-nickel zone, possibly related to a sill of ferropicritic composition (Wares and Mungall, 1997). The West Lens may have been tectonically detached by fault movement from a larger zone of magmatic mineralization.
The East Lens appears to have a different origin and may represent an epigenetic hydrothermal copper-nickel mineralization. The mineralization is laminated and parallel to the penetrative schistosity of the basalt but is often folded. The sulphides are rich in copper but contain lower quantities of nickel than in the West Lens. The mineralization contains 530-1800 ppb Pd but low values of platinum (Beauchamp, 2001). The current thought is that the East Lens formed as a result of the emplacement of epigenetic sulphides along the schistosity in the host basalt. The sulphides may have precipitated from hydrothermal fluids that could have been altered as a result of an interaction with the host basaltic igneous rocks (Clark and Wares, 2005).
The East Lens reported 2.4% Cu and 0.07% Ni over 4.7 m, not true thickness from a fault zone of sericitized basalt that contains disseminated sulfides in drill hole HR 95-2. The section of mineralization including disseminated and massive mineralization averages 1.28% Cu and 0.04% Ni over 14.6 m, not true thickness.
Drilling 300 m north of the Pio Lake Zone in 1996 confirmed the presence of massive sulphide mineralization in altered basalt. Drilling in HR 96-73 reported an average grade of 2.72% Cu and 0.32% Ni over 2.28 m, and in HR 96-90 an average of 2.0% Cu and 0.34% Ni over 4.6 m in altered basalts north of the northeast- trending fault.
Additional zones of mineralization in the region are at the Gabbro Zone, about 600 m to the south of the Pio Lake Zone where a composite 0.66% Cu and 0.23% Ni were intersected over 28.6 m in glomeroporphyritic gabbro in HR 96-77 at the contact between peridotite above, and basalt below. The hole east of the fold axis of an overturned syncline drilled into peridotite. The nearby drill hole HR 96-78 was collared into the lower part of the porphyritic gabbro but was not sampled. This mineralization is identical in lithology and style to that described at the Hopes Advance Main Zone and at Schindler disseminated.