The Windfall Lake Gold project is located in the province of Quebec,
approximately 200 kilometres northeast of Val-d’Or and 115 kilometres
east of the town of Lebel-sur-Quévillon and is accessible year-round
through a network of well-maintained logging roads (Figure 1). The
property is located north of the 49th parallel and is subject to the
provisions of the James Bay and Northern Quebec Agreement executed in
1975. The Windfall Lake Gold project falls within the traditional
territory of the Waswanipi Cree First Nation.
The Windfall Lake property is 100 percent owned by Oban Mining Corp.
and comprises 285 individual claims covering an aggregate area of
approximately 12,400 hectares.
Eagle Hill Exploration Corporation, recently acquired by Oban Mining
Corp., has established an Advance Exploration Agreement with the Cree
First Nation of Waswanipi, the Grand Council of the Crees (Eeyou
Istchee), and the Cree Regional Authority regarding exploration and
development of the Windfall Lake Gold Project.
The Windfall Lake property occurs within the Urban-Barry Greenstone
Belt located in the eastern part of the Abitibi Subprovince. The
Urban-Barry Greenstone Belt has an east-west extent of 135 kilometres
and is 4 to 20 kilometres wide. Oban Mining is currently the largest
stakeholder in the Urban Barry Greenstone Belt with over 40% of the land
staked.
At the Windfall Lake deposit, the volcanic stratigraphy trends to the
northeast and dips moderately towards the southeast. The tholeiitic
volcanic rocks are intruded by a series of NE- to E-trending
calc-alkalic porphyry dikes that are intimately associated in space and
in time with the important gold mineralization. Alteration is
principally silica-sericite-tourmaline with a peripheral
chlorite-carbonate halo.
Figure 2. Geology map of the Abitibi Greenstone Belt with location of the Windfall Property in the Urban-Barry belt
Gold mineralization
The most significant gold mineralization defined to date on the
Windfall Lake Property occurs in the Main Zone, located in central-south
portion of the property. Additional gold mineralization is also present
in the peripheral F-11, F-17, and F-51 zones (Figure 3).
The gold mineralization in the Main Zone occurs in several
sub-vertical, northeast-trending lenses measuring between 2 and 35
meters in horizontal thickness. To date, better lateral and vertical
continuity has been identified as a series of sub parallel lenses along
the corridors of Zone 27, Caribou, and Mallard that all have the same
style of gold mineralization associated with sulphide replacement,
generally pyrite, occurring as disseminations, stockworks and breccias.
Within the lenses, there are a number of sub-horizontal to shallow
easterly plunging, higher grade, and more continuous shoots extending
for over 700 meters along strike.
The gold-bearing pyrite stockwork mainly consists of pyrite stringers
with minor tourmaline needles; the stringers are typically less than 1
centimeter in thickness and are oriented in several directions (Figure
4). Trace amounts of chalcopyrite, sphalerite, pyrrhotite, arsenopyrite,
tetrahedrite, and bismuth sulfosalts are also present around pyrite
grains but also as inclusions in pyrite of the pyrite stockwork. Specks
of gold are sometimes visible in the pyrite stringers and also in
semi-massive sulphide bands, tourmaline veins or in the altered part of
the rock around these features.
The stockwork mineralization is hosted within volcanic rocks and
various generations of porphyry dikes except for the Red Dog dikes,
which postdate the emplacement of the pyrite stockwork. Some of the
fragments in porphyry dikes were altered and mineralized prior to being
brecciated and porphyry dikes locally crosscut the pyrite stockwork
mineralization, suggesting that emplacement of the gold mineralization
was broadly coeval with the intrusion of the porphyry dikes. The
distribution of the pyrite stockwork is greatly influenced by the
geometry of the dikes, specifically for Zone 27 and the Caribou
corridor, which are spatially associated with 2- to 30-metre thick
northeast-trending porphyry dikes (Figure 5)
Gold mineralization (several ounces per tonne) is locally associated
with brecciated quartz veins with colloform and crustiform banding
(Figure 6). The veins are moderately dipping and trend
northeast-southwest. The largest zone is vein 466 in the Zone 27
corridor with a strike extent of 300 metres and a dip extent of 200
metres. At a minimum width of 0.5 metres and an average width of
approximately 1.5 metres, the colloform-crustiform veins can reach a
thickness nearly 6 metres, locally.
The auriferous zones are cross-cut at depth by the quartz monzonite
Red Dog sill, which is up to 100 meters thick and dips approximately 30
degrees to the southeast. Drilling by Eagle Hill indicates that the gold
mineralization continues below the Red Dog sill to a depth of at least
870 meters below surface and remains open along strike and at depth.
The characteristics of the gold mineralization in the Main Zone are
similar to intrusion-related gold mineralization described as atypical
greenstone-hosted deposits by Robert (2007). Although these atypical
deposits display similar regional-scale controls and commonly occur in
the same camps as orogenic deposits, they differ in styles of
mineralization, metal association, interpreted crustal levels of
emplacement, and relative age. Those atypical greenstone-hosted gold
deposits show a close spatial association with high level porphyry
stocks and dykes. The Kanowna Belle gold deposit in Western Australia
would be a good analogy to Windfall Lake gold deposit.
Figure 3. Surface projection of gold zones of the Windfall Lake Gold Deposit with location of the existing underground decline.
Figure 4.Typical gold-bearing
pyrite mineralization at Windfall Lake Gold Deposit. a) Outcrop of
pyrite stockwork; b) Fresh sample with pyrite stockwork and
silica-sericite alteration; c) pyrite stockwork in core. Red numbers are
gold values in grams per tonnes; d) pyrite stockwork and disseminated
pyrite with tourmaline needles (small black dots).
High-grade gold resource
A mineral resource update completed by SRK (Canada) in November 2014
estimated 748,000 ounces of gold at 8.42 g/t gold in the indicated
category, and 860,000 ounces of gold at 7.62 g/t gold in the inferred
category. The bulk of mineralization averages ~10 g/t over 5 metres,
with very high-grade pockets up to 248 g/t over 12.4 metres in some
areas. Drill holes in the gold zones demonstrate good grade distribution
along the entire mineralized interval. Preliminary metallurgical tests
indicate a gold recovery of 95.7% using a standard gravity and flotation
circuit, followed by cyanidation.
Table 1. Mineral Resource Statement (From SRK Consulting, November 13, 2014).
Reported at a cut-off grade of 3.0 g/t gold, assuming an underground
extraction scenario with an assumed gold price of US$1,200/oz and
metallurgical recovery of 96%. Inferred resources have a great amount of
uncertainty as to their existence and as to whether they can be mined
legally or economically. It cannot be assumed that all or any part of
the inferred resources will ever be upgraded to a higher category.
Mineral resources are not mineral reserves and do not have demonstrated
economic viability.
Resources : Oban Mining
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