The Wasamac deposit is a gold deposit of replacement type with close coexistence of gold and pyrite disseminated in the altered Wasa Shear Zone. Hydrothermal alteration is well developed, and alteration minerals have distinct zonation from the orebody outward: albite-pyrite to carbonate-hematite to muscovite-chlorite. Gold mineralization is closely associated with these alterations, especially albite-pyrite alteration.

The Wasa Shear Zone runs through the centre of the property in an east-west fashion. This shear zone trends at an azimuth of 265°, has a 50° to 60° dip to the north and a maximum thickness of 80 m. It is characterized by the development of a strong mylonitic fabric and an intense hydrothermal alteration that destroyed the primary structures and textures of the protolith. Mineral assemblages of rocks within the shear zone consist of chlorite, carbonate, hematite, albite and sericite in the middle of the zone. Gold is associated with a dissemination of fine pyrite in the altered portions of the shear zone.

The Main Zone can be described as a well laminated mineralized zone. It is located near the centre of the property, within the Wasa Shear Zone and high grade areas display true widths of 10 m to 15 m (up to 25 m locally) over a strike length of 400 m. Gold mineralization is associated with quartz, carbonate, sericite, albite, pyrite and chlorite inside the shear zone. Visible gold is rare, and strong gold assays are generally associated with high silica content and a lot of fine grained pyrite (Gill, 1947). If the entire mineralized zone is considered, including lower grade parts, the width of the mineralized zone can be up to 50 m. At depth, in the western part of the Main Zone, there is also gold mineralization in the footwall of the shear zone.

Located some 400 m east of the Main Zone, Zone 1 has a similar mineralogical assemblage. The high grade part displays true widths of 4.5 m to 7.5 m over a strike length of 150 m. The thickness of the mineralized envelop can be up to 20 m.

The higher grade part of Zone 2 has an average thickness of three to six metres over a strike length of 225 m. This zone was partially developed from underground, but no production was recorded. This mineralized zone is located in the upper part of the shear zone, near the hanging wall.

The mineralization of the Zone 3 is located in the lower part of the shear zone, near the footwall, below the MacWin Zone.

The MacWin Zone is also associated with the Wasa Shear Zone. The gold mineralization went out of the shear zone, as irregular mineralized zones are found in the rhyolite located just at the hanging wall of the shear.

Located approximately 300 m south of the Main Zone, the Wildcat Zone was the first gold showing to be discovered on the property (1936). This gold bearing zone consists of a carbonate altered zone at the margins of a gabbroic unit. Gold mineralization is associated with quartz carbonate veinlets containing fine grained pyrite. The pyrite mineralization is also present throughout the altered halo as disseminations.

The Wasamac underground mine consist of five zones: Main Zone (“MZ”), Zone 1 (“Z1”), Zone 2 (“Z2”), Zone 3 (“Z3”), Zone 4 (“Z4”). It is located approximately 15 km west of Rouyn Noranda, Quebec, Canada, within the heart of the Abitibi gold mining camp. The mine design strategy is based on high speed development and Rail-Veyor® technology to complete the pre production infrastructures from years 2021 to 2023 and to achieve an average ore production rate of 6,000 tpd from years 2024 to 2031 when the mine is running at full capacity. The strategy is to recover higher grade zones in the early years of the Project.

Access into the mine is via twin declines extending from the portal located at 1,500 m east of MZ with a length of 2,456 m and grade of -7.50% down to the garage at 4990L above MZ. By using the twin decline design and the Rail-Veyor®, the system for removal of material is independent from the access for workers and supplies; this reduces the possibility of equipment collisions and travel delays experienced with trucking.

The Rail-Veyor® Integrated Top Down Long Hole Stoping Method was selected for the Wasamac Project based on the geometry of the mineralized zones, vertical dip, as well as economic factors. There are two types of mining methods: one with 40 m interval Rail-Veyor® main levels and another with 20 m interval Rail-Veyor® main levels. The 40 m interval involves accessing two levels of stopes using three longitudinal rubber tire drifts. The drift above the top stope is used for drilling, loading, blasting of the top stope and backfilling of the two levels of stopes. The drift above the bottom stope drift is for down hole drilling, loading, blasting of the bottom stope. The drift below the bottom stope at the main level is for mucking material onto the reclaim feeder that loads the Rail-Veyor® situated 30 m to the south of the orebody in the hanging wall.

The 20 m interval method involves accessing one level of stopes using two longitudinal rubber tire drifts, one above the stope for down hole drilling, loading, blasting and backfilling, and one below the stope at the main level for mucking. The ore handling process for both types of mining methods is the same. The empty stopes are backfilled with paste backfill from the underground paste fill plant. Stopes will be mined following a retreating sequence towards the closest twin ramps. Many horizons can be mined at the same time to maintain productivity level.

In areas with wide ore thicknesses, there will be addition of sill drifts that are in between two rubber tire drifts but shifted 4 m below. This will allow the recovery of stope apexes.

The development sequence focuses on prioritizing the high grade mineralized zones, specifically MZ. The mining sequence requires the excavation of an opening a V-30 slot raise from Machines Rogers International. Once the development is completed, the mineralized zone is surveyed with precision for the preparation of the drilling and blasting pattern. Waste material generated from the drift development will be transported by Rail-Veyor® and used to create the paste backfill of the stopes.

The mining method requires the use of paste backfill to provide better ground stability and lower dilution while mining. As recommended by Outotec, the maximum slurry feed to batch will be 6,000 tpd, and 100% unclassified tails feed from the mill will be pumped to the backfill plant or tailings facilities. This approach would avoid the need of double systems and management of complex tailings. Classification has been omitted because it would add both complexity and risk to the pressure filtration for disposal, which likely outweigh the likely benefits from classification. Double panel topes will be backfilled in one shot from the top panel to the bottom panel, once the bottom panel is mined out. All stopes will be filled with paste backfill with an estimated 7% binder content, and when and where appropriate, with a blend of rock fill and paste backfill, to reduce the amount of waste development rock to be hauled to surface.

The Primary Crusher will be operating underground. The crushed material will be transported to surface from the underground mining area using conventional conveyors and stored on surface in a covered stockpile to control dust.

SAG Mill Circuit
The reclaimed coarse ore will be conveyed to the SAG mill. Water will be added to the mill feed chute to achieve the desired slurry density within the mill. Given the grindability results, a SAG mill size of Ø7.92 m x 4.72 m (Ø26’ x 15.5’) was selected. The mill will be installed with a single 5,500 kW motor. The mill drive train will include a single-pinion arrangement powered by a lowspeed synchronous motor of 5,500 kW (7,376 hp). This selection allows for the ore to be ground from an F80 of 140 mm to a P80 of 0.9 mm.

The mill will be operated with a charge of Ø125 mm steel balls. New media will be intermittently added to the mill feed chute via a ball bin fitted with a discharge gate to maintain the power draw and throughput capability.

The coarse fraction obtained from the 3.05 m x 6.71 m (10’ x 22’) screen with apertures of approximately 4-6 mm installed below the SAG mill discharge trunnion will be conveyed to a pebble crusher before being returned to the SAG mill feed conveyor. The screen undersize will drop into a pumpbox receiving this stream as well as the ball mill discharge.

The SAG mill area will be serviced by an overhead crane for maintenance duties and ball addition with a bucket loaded from a ball bin located within the process plant building. Two sump pumps will be installed to collect spillage directed towards the sumps with a sloping floor.

Ball Mill Circuit
A ball mill, Ø5.49 m x 9.75 m (Ø18’ x 32’), fitted with a trommel screen was selected based on the design metallurgical energy requirement of 15.0 kWh/t. The maximum required power is equal to 5,500 kW (7,376 hp).

The ball mill will be operated in closed-circuit with a cluster of Ø400 mm cyclones producing an average product P80 of 60 µm as trash screen feed, with a pulp density of 30% solids (weight basis). A sufficient number of cyclones will be provided to cover a circulating load of up to 350%, whereas the nominal flow is based on 250%. The ball mill may be charged to 35% of its volume with Ø38 mm steel balls added intermittently via a ball bin located at the ball mill feed chute. Water will be added to the cyclone feed pumpbox to control the cyclone feed slurry density.

The cyclone overflow will be sent to the linear motion trash screen ahead of the pre-leach thickener while the oversize material in the underflow will return to the ball mill for further grinding.

The ball mill area will be serviced by an overhead crane used for maintenance duties and for grinding media addition to the mill, from a ball bin located within the process plant building. One sump pumps, will be installed to collect spillage directed towards the sump with sloping basement floor.

The process plant will consist of crushing, stockpiling, primary and secondary grinding, leaching prior to a carbon-in–pulp (“CIP”) circuit, followed by cyanide destruction. Based on the mine backfill scheduling, material will be pumped underground to a paste backfill plant. When the paste backfill plant will not be operating, tailings will be pumped to a filtration plant where the filter cake will be sent to a dry-stack tailings pile. An adsorption-desorption-recovery (“ADR") circuit and a gold room will recover gold from activated carbon and will produce doré. The plant will also include a reagent preparation area, two process water circuits (cyanide bearing and cyanidefree), a fresh water circuit, as well as low-pressure and compressed air distribution systems.

Prior to leaching, the ground slurry will pass through a trash screen before being thickened to 60% solids (weight basis) in a Ø22 m pre leach thickener. The thickener was sized using dynamic settling test results. ........