Summary

Deposit type

• Vein / narrow vein
• Replacement
• Intrusion related

Summary:

The Windfall deposit is classified as a pre-Temiskaming intrusion-associated gold deposit due to: 1) a temporal and spatial association of gold with felsic calc-alkaline QFP intrusions; and 2) the main gold event (i.e., vein- and replacement-type mineralization) being interpreted to pre-date known regional scale deformation.

Mineralization consists of a network of quartz-carbonate-pyrite-tourmaline veins and an associated silica-sericite-pyrite alteration assemblage. The mineralization and alteration have strike lengths of >2 km that show, as of yet, no recognized vertical zoning. Gold mineralization is only locally spatially associated with calc-alkaline QFP dikes but shows no genetic association with them. The QFP intrusions were emplaced mainly as a product of tectonism and deformation and act only as competent host rocks that concentrate deformation and gold-bearing hydrothermal fluids.

Mineralization
Gold mineralization in the Windfall deposit is observed in two main settings and include: 1) vein-type mineralization; and 2) replacement type mineralization.

Vein-type mineralization consists of grey to translucent coloured quartz veins that contain subordinate amounts of ankerite, tourmaline, pyrite and commonly visible gold. The veins have sharp contact margins that are straight or folded. Texturally these veins are massive, but locally can form laminated textures characteristic of fault-fill veins (Robert and Poulsen, 2001). The veins vary in thickness from 0.1 m to 1 m and are generally associated with the highest gold grades ranging on average from 20 g/t to >100 g/t. In the veins, sulphide content ranges from 1% to 80% and is dominated by pyrite with minor concentrations (<1% total sulphide) of chalcopyrite, sphalerite, arsenopyrite, galena, pyrrhotite, tennantite and other Bi-Te minerals, as identified by internal petrographic and microanalytical analyses. This mineralization style is commonly observed to occur in felsic volcanic dominated domains of the deposit (i.e., Caribou and Lynx).

Replacement-type mineralization occurs at the margins of vein-type mineralization or in high strain zones that lack the development of quartz veins. This mineralization style consists of pyrite replacement zones and stockworks associated with a strong pervasive silica-sericite ankerite ± tourmaline alteration of the host rock. The gangue and precious-metals are identical to those mentioned above in the vein-type mineralization. The gold is associated with disseminated pyrite, which varies from 1 to 80% over mineralized intervals. This mineralization style is commonly observed to occur in the mafic volcanic dominated domains of the deposit (i.e., Main zone).

Visible gold mineralization is commonly observed in the Windfall deposit. In drill core, the gold ranges from millimetre-sized nuggets to locally centimetre sized patches commonly associated with post-vein formation fractures containing cloudy white quartz-carbonate. The late overprint of visible gold suggests late-stage remobilization.

Other than the auriferous vein-type and replacement-type mineralization noted above, less significant vein-types include: 1) early gold barren carbonate-quartz veins with colloform textures (pre-ore); 2) gold-barren sheeted blue quartz veins (pre-ore); 3) laminated-quartz carbonate- tourmaline veins and tourmaline breccias (post-ore); 4) carbonate-quartz stockworks and breccias cross-cutting mineralized zones and remobilizing gold (post-ore); and 5) late white quartz veins with coarse pyrite and remobilized gold (post-ore).

At the Windfall deposit, the high-grade gold mineralization is contained within narrow deformation zones that cross-cut the synvolcanic rocks and syn-deformation QFP intrusions and are locally spatially associated with the contacts of the latter. Mineralization consists of vein-type quartz- carbonate-pyrite-tourmaline-gold veins, or replacement-type pyrite-rich corridors that are zoned from a high-grade inner gold-silica > silica-carbonate-tourmaline mineral assemblage to an outward low-grade gold-sericite > sericite-carbonate-tourmaline assemblage, which in turn transitions to a background of gold-barren chlorite-carbonate > sericite.

The mineralization is currently known for a lateral extent of 3,000 m and a confident vertical extent of approximately 1,600 m. It is separated into four sectors: the Lynx zone (Lynx Main, Lynx HW, Lynx SW, Triple Lynx and Lynx 4), the Main zone (Zone 27, Caribou 1, Caribou 2, Caribou Extension, Bobcat, Mallard, Windfall North, F-Zones), the Underdog zone, and the Triple 8 zone. Current drilling is testing the extensions of many of these zones, mainly in the Lynx zone. All zones generally trend east-northeast and plunge roughly 35° to 40°.

The Lynx zone consists of five gold mineralized zones located in the east-northeast portion of the deposit. Most of the Lynx mineralization zones form an extensive anastomosed network of quartz-rich and pyrite-rich veins hosted within strongly silicified felsic volcanic rocks or gabbros. This system is located on the southern limb of an open fold plunging at 40º towards the east-northeast along the Bank fault-shear zone.

The Main zone consists of five gold mineralized zones located in the central portion of the deposit. The gold mineralization is constrained along east-northeast oriented contacts of narrow subvertical granodioritic dikes within tilted volcanic rocks. Most mineralized envelopes in the Main zone are associated with pyritic stringers occurring near contacts between volcanic rocks and younger intrusive rocks. Generally, the gold mineralization is hosted in a mafic dominant domain (i.e., basalt and andesite) with lesser syn-deformation QFP intrusions and mafic intrusions.

The Underdog zone is located in the southwestern portion of the deposit and is separated from the Main zone by the post-mineral Red Dog QFP intrusion. The gold mineralization is hosted in a syn-deformation QFP dominant domain (i.e., I2P, I1P QFP dikes) with minor mafic and felsic volcanic rock. The mineralization in the Underdog zone is composed of disseminated to semi-massive pyrite intervals associated with strong silica and sericite alteration, generally following main intrusive contacts and/or deformation zones. The top of this deeper mineral zone starts at around 600 m depth and continues to depths of roughly 1,600 m where it is still open at depth and down-plunge.

The F-Zones are located in the northern portion of the deposit. Gold mineralization in the F-17, F-11 and F-51 zones differs from that of the Main and Lynx zones. The F-Zones trend to the northeast, subparallel to the Main zone, but dip steeply to the north. F-17 and F-51 are aligned along the same trend but separated by approximately 800 m. The zones are interpreted to be associated to the Northern fault, and the mineralization is typical of shear-hosted replacement-type mineralization. Mineralization continuity between the two zones cannot be established from the current drilling data. F-11 lies in a similar structural context but is located 500 m to the northwest.

Mining Methods

• Longhole stoping
• Longitudinal stoping

Summary:

The Windfall Project mineralization varies in dip and thickness both along strike and at depth. All geometries are suitably extracted using the Longitudinal Longhole Stoping method with backfill.

The Windfall Project has three primary zones: Lynx (Lynx zone), Main and Underdog (Main zone). All zones trend roughly east-northeast and dip vertically between 45° to 90°. The Main zone is the western portion of the planned mining area and the Lynx zone is the eastern portion. The zones are accessed by three ramp systems, with two surface portals for transportation and material haulage.

Longitudinal longhole mining is suitable for the Windfall Project, where the dip of the mineralization is 45° or greater, and the materialized zones are of sufficient width and grade that the estimated dilution does not eliminate the profitable recovery of the material. Mining will consist of an undercut level and an overcut level, each accessed from the main ramp or an access drift. Each sill will be accessed perpendicularly from the ramp or access drift, and then developed along strike of the vein to the economic extents of the mineralization.

Once sill development is completed on each level, production holes are drilled between the sills and then blasted until the stoping panel is completed. Following cavity monitoring of the stope, the void is then prepared for backfill. Once a sufficient distance along strike (one to two stope lengths) has been extracted and backfilled, mining can progress either up-dip or down-dip and extraction can recommence opening another mining location.

Stope heights of 20 m were selected based on the expected vertical continuity of the mineralization. Stope heights are measured from the floor of the undercut to the floor of the overcut level. A maximum panel length of 30 m for stope heights of 20 m has been established before being backfilled.

The underground mine plan targets a production rate of 3,400 tpd. Stope dimensions are 20 metres in height, median of 25 metres in strike length, and have a median thickness of 4.4 m with a minimum thickness of 3.0 m. Ore will be extracted using a fleet of 14 and 18 tonne load-haul-dump machines (“LHDs”) and 54 tonne haul trucks using a ramp to surface.

The ramps and level accesses (up to the vent raise access) will be 5.2 m high by 5.5 m wide allowing the passage of 54 t haulage trucks as well as secondary ventilation ducting and service piping. Ore access drives towards the ore zone will be 4.5 m high by 4.3 m wide, while development in mineralized material will be 4.5 m high by 4.0 m wide.

The proposed lateral development schedule for Windfall has been established using performances of 10 m per day per crew, with a maximum advance of 2 m per day for ore drives, 4 m per day for priority ramp headings and 3 m per day for all other headings. Additionally, a limit of 10 m per day has been applied to each level. Up to five crews will be needed during the life of the Project.

Vertical development over 30 m will be completed using a raise boring machine, owned and operated by a contractor. Vertical development of less than 30 m will be completed through longhole drop raise methods using production drills.

Early pre-production development focuses on the establishment of level accesses and their related infrastructure, garage infrastructure, diamond drill headings, and priority level ore drives within the existing Lynx central ramp and Lynx 4-HW down ramp.

A proposed diamond drill program to bring all material into the Measured resource category has been incorporated into the schedule, using a maximum of six diamond drills, operating at 60 m/d. Ore drive development within lenses being tested were prevented from starting until drilling for that setup is complete.

The selected mining method requires the use of backfill to minimize dilution and to maximize recovery. The construction of the paste backfill facility will not be complete until commercial production. During this initial period, cemented rockfill (“CRF”) will be used. Proposed to begin once construction is complete, paste will be pumped underground from surface through a borehole and routed to the stope level through 8-inch schedule 80 and HDPE piping. Downhole stopes will be paste-filled from their overcut level while uphole stopes will be filled through a pastehole drilled from the undercut level.

A mobile cemented rockfill mixing truck, with a 12-t capacity of dry material, will bring the cement from surface to the backfill site, where it will use an onboard grout mixer to create cement slurry batches for dispensing into the backfill LHD. A 5% cement content in the backfill was used for costestimates. The use of the Swatcrete Mobile CRF mixing truck eliminates the need for a complete cement mix/slurry distribution network and an underground storage silo.

Comminution

Crushers and Mills

Summary:

Crushing, Storage and Reclaim
Ore transported from the underground mine will have a F80 of 400 mm. Each rear dump truck from Windfall Mine ramps will carry a total of 50 tonnes per load. A run-of mine (“ROM”) stockpile close to the crushing plant will be primarily utilized for emergency storage. A static grizzly (400 mm), mounted above the ROM bin, and a rock breaker will be installed. Material is withdrawn from below to the vibrating grizzly where the oversize material is directed to an open circuit jaw crusher to further reduce the material to a P80 of 114 mm. A baghouse dust collection system will capture the dust created by the crushing operations. The jaw crusher product and vibrating grizzly undersized are collected on a conveyor belt that feeds the crushed ore silo. The live silo capacity is 4,010 t, or 26 hours of nominal capacity.

Two discharge points from the silo feed two feeders, respectively. The feeders discharge to the semi-autogenous grinding (“SAG”) mill feed conveyor that will convey the crushed rock to the SAG mill feed chute. Fine material from the feeders is captured on two dribble conveyors that also discharge onto the SAG mill feed conveyor. The SAG mill feed conveyor will be fitted with a weightometer.

Grinding Circuit
The grinding circuit will be a SABC circuit, comprised of a single variable speed SAG and a single variable speed ball mill. The SAG mill will operate in closed-circuit with a pebble crusher, followed by a ball mill, operated in closed-circuit with cyclones. The product particle size exiting the grinding circuit cyclone overflow will contain 80% passing 37 µm material. The SAG and ball mill area is serviced by overhead crane.

SAG Mill Circuit
The reclaimed crushed rock is conveyed to the SAG mill feed chute via the SAG mill feed conveyor. A SAG mill size of Ø7.32 m x 2.82 m (Ø24’ x 9.25’) effective grinding length (“EGL”) was selected with a total installed power of 2,800 kW to grind the rock to a P80 of 1 mm.

The mill is operated with a charge of Ø127 mm steel balls.

The SAG mill product discharges to a single deck vibrating screen. The oversize is conveyed to the pebble crusher and the undersize discharges into a pump box which then feeds the ball mill via a cyclone cluster.

Oversize from the SAG mill discharge screen will be conveyed to the pebble crusher via two belt conveyors. A self-cleaning tramp metal magnet will be mounted above both pebble recycle conveyors.

Undersize from the SAG mill discharge screen will be pumped to the cyclone cluster via a pump box.

Ball Mill Circuit
A ball mill, Ø5.18 m x 9.5 m (Ø17’ x 31’) EGL, fitted with a trommel screen, was selected for secondary grinding. The total installed power is 4,200 kW. The ball mill will be operated in closed-circuit with a cluster of hydrocyclones producing an average cyclone overflow product P80 of 37 µm. This product will feed the pre-leach thickener.

The ball mill will be charged with Ø50.8 mm steel balls. The ball mill is fitted with a trommel screen and discharges into a pump box which then feeds the gravity concentrators via the gravity concentrator screens.

The cyclone overflow is sent to the vibrating trash screen ahead of the pre-leach thickener and the CIP circuit, while the oversize material in the underflow is returned to the ball mill.

Processing

• Smelting
• Gravity separation
• Carbon re-activation kiln
• Centrifugal concentrator
• Crush & Screen plant
• Electric furnace
• Intensive Cyanidation Reactor (ICR)
• Concentrate leach
• Agitated tank (VAT) leaching
• Carbon in pulp (CIP)
• Carbon adsorption-desorption-recovery (ADR)
• Elution
• Dewatering
• Filter press
• Solvent Extraction & Electrowinning
• Cyanide (reagent)

Summary:

The process plant consists of primary crushing, followed by a grinding circuit consisting of a semi- autogenous mill (“SAG”) in closed circuit with a pebble crusher and ball mill (in closed circuit with cyclones – (“SABC”) circuit). A gravity circuit, followed by intensive leaching, recovers free gold from the grinded cyclone underflow, while the cyclone overflow is treated in a leaching and carbon-in–pulp (“CIP”) circuit. Gold and silver are recovered in an adsorption-desorption-recovery (“ADR") circuit. Electrowinning (“EW”) cells and a gold room recover the gold and produce doré. The plant also includes a reagent preparation area and process and industrial water circuits to service the entire plant. A cyanide destruction circuit is also included to treat CIP tails before being sent to the tailings filtration plant.

The design criteria to determine the sizing of the equipment are based on a nominal process plant throughput capability of 3,400 tpd. With a 92% plant availability and design factor used, the maximal daily throughput is 4,080 tpd.

Gravity Circuit
The gravity circuit feed pump box at the ball mill trommel undersize will feed two gravity scalping screens via a split box. The coarse material from the scalping screen will return directly at the ball mill feed. The undersized material from the screens will feed two gravity concentrators, arranged in parallel. The gold concentrate from both gravity concentrators will feed an intensive leaching reactor (“ILR”) operating by batch, one batch per day. The gravity concentrator tails will return to the cyclone feed pump box. The pregnant leach solution from the ILR will be pumped to a dedicated electrowinning cell via a pregnant solution tank located in the gold room. A sampler will be installed on the pregnant leach solution line. The ILR tailings will be returned to the cyclone feed pump box via a pump.

Carbon-in-Pulp
Prior to leaching, the ground slurry received from the cyclone overflow will pass through a trash screen before feeding the pre-leach thickener feed box. The pre-leach thickener diameter is Ø24 m. Underflow from the pre-leach thickener at 50% (w/w) will be pumped to the leaching circuit. The thickener overflow water is sent to the process water tank.

The pre-leach thickener underflow slurry will be pumped to the leaching circuit, consisting of one pre-aeration tank and four leaching tanks. Each tank will be 14 m in diameter, mechanically agitated, and operating in series. Lead nitrate and sodium cyanide will also be added to leach gold along with oxygen sparged. The leached slurry will flow from the final leaching tank to the CIP feed launder.

The CIP circuit consists of nine CIP tanks operating in carousel mode. In this mode of operation, the activated carbon is kept within the CIP tanks, while the slurry is pumped between tanks through CIP pumping interstage screens. The slurry inlet and outlet are moved to achieve a countercurrent flow of pulp to the carbon in the tank by alternating the feed and discharge CIP tank.

Adsorption, Desorption and Recovery Circuit
The gold recovery circuits are based on the processing of 7 tpd of loaded carbon with a high pressure Zadra process.

Loaded carbon from the CIP circuits is transferred to a loaded carbon screen via loaded carbon pumps. The undersize from this screen is recycled to the CIP feed launder. The oversize is sent intermittently to the 47-t capacity acid wash vessel. Carbon transport water drains from the acid wash vessel and is sent to the fine carbon collection tank.

A batch of 3% (w/w) hydrochloric acid cold solution is prepared in the dilute acid wash tank by transferring concentrated acid 28% and industrial water. The acid wash sequence will involve the injection of the dilute acid solution into the column, by the dilute acid circulation pump, via the feed manifold located beneath the column.

Carbon elution, or stripping, is initiated when a barren strip solution of 1% NaOH and 0.5% NaCN circulates through the elution column at a flow rate of two bed volumes per hour for 10.5 hours at an elevated temperature and pressure. The solution exits the elution column as pregnant solution (e.g. loaded strip solution). The recirculated strip solution flows from the barren tank through a heat exchanger before entering the stripping vessel.

After a carbon strip is complete, transport water flows to the elution column and a pump transfers the carbon to a dewatering screen. The undersize fraction from the carbon dewatering screen reports to the fine carbon collection tank and the oversize reports to the carbon regeneration kiln feed bin.

Carbon Regeneration and Fines Handling
A carbon regeneration kiln reactivates the stripped carbon. The regeneration kiln operates at a nominal temperature of 700-800°C to reactivate the carbon activity close to its original level.

The kiln discharge reports to the carbon quench tank.

Settled carbon from the fine carbon collection tank will be transferred to a plate-and-frame filter press for dewatering. The filter press cake is bagged in tote bags and transported off-site once sufficient inventory has built up. The carbon fines filter press filtrate returns to the fine carbon collection tank.

Electrowinning and Gold Casting
Three EW cells recover gold and silver from the pregnant strip solution. The solution exiting the cells reports to the EW cell discharge pump box and is pumped to the barren stripping solution tank. A separate dedicated EW cell treats the intensive cyanidation pregnant solution.

A fourth EW cell will be dedicated to the ILR pregnant solution. Pregnant eluate from the intensive cyanidation reactor will be stored within a dedicated ILR pregnant eluate tank. Once sufficient pregnant eluate is available, within the ILR pregnant eluate tank, the EW sequence will be initiated by starting the ILR EW Feed Pump.

A filter press removes excess moisture from the separated gold sludge. Following filtration, the precious metal sludge is dried in an oven.

The dry EW sludge is cooled and mixed with fluxes before being fed to the induction smelting furnace. The gold and silver doré is poured from the furnace into a cascade of moulds. The refining area and gold room are secure areas.

Water Supply

Summary:

Water requirements for the plant are divided into two main areas, industrial water and process water.

The total industrial water requirement for the process plant (including process water tank makeup) was estimated at approximately 194 m3/d.

Potable Water
The raw water for the Windfall site will be supplied by an underground water well P5, which is located approximately 1.1 km away from the potable water production unit. The pumped raw water is considered of good quality but requires treatment for the removal of iron and manganese (green sand filters), as well as chlorination before its distribution through the aqueduct network.

For the potable treatment process, a pre-assembled unit is considered. The drinking water production system will be located at the entrance of the site, in four prefabricated units. Two underground tanks will be used to store treated water before its distribution.

The preliminary design of the system is based on the various uses planned for the camp and other infrastructure. It offers a capacity adjusted to an occupancy which will also support the construction phase. The estimated average daily flow is 135 m³/d, with an hourly peak at 50 m³/h and a daily peak estimated at 270 m³.

Water Management
The following water management infrastructure is considered as existing:
- The collection pond;
- Perimeter ditches around the existing waste rock stockpile (“WRS”);
- Ponds A, D and P and ditches around the WRS;
- Water Treatment Plant;
- Bulk phase ammonia water treatment plant (“WTP”).

Pond SP1 will no longer be used.

Water management infrastructure for the mine will include:
- Non-contact water diversion ditches;
- Contact water collection ditches;
- TMF ponds and other collection ponds;
- Pumping systems including sumps, pumps and pipeline;
- Polishing pond;
- Existing water management structures that will be integrated with the new system of ditches and ponds.

Commodity Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Consultant - Costs	Colin Hardie		Nov 25, 2022
Consultant - Infrastructure	Eric Poirier		Nov 25, 2022
Consultant - Recovery Methods & Costs	Mathieu Belisle		Nov 25, 2022
Engineering Manager	Hughes Perigny		May 28, 2025
Planning Manager	Patrick Langlais		May 15, 2025
Supply Chain Director	Jean-Francois Thibault		May 15, 2025
Vice President of Mining	Jason Sander		May 15, 2025
VP, Environmental, Social, and Governance	Andreanne Boisvert		May 28, 2025