Overview

Deposit type

• VMS

Summary:

The geology that underlies the LaRonde mine consists of three east-west-trending, steeply south-dipping and generally south-facing regional groups of rock formations. From north to south, they are: (i) 400 metres (approximate true thickness) of the Kewagama Group, which is made up of a thick band of interbedded wacke; (ii) 1,500 metres of the Blake River Group, a volcanic assemblage that hosts all the known economic mineralization on the property; and (iii) 500 metres of the Cadillac Group, made up of a thick band of wacke interbedded with pelitic schist and minor iron formation.

Zones of strong sericite and chlorite alteration that enclose massive to disseminated sulphide mineralization (including the ore that is mined for gold, silver, zinc and copper at the LaRonde mine) follow steeply dipping, eastwest-trending, anastomosing shear zone structures within the Blake River Group volcanic units across the property. These shear zones are part of the larger Doyon-Dumagami Structural Zone that hosts several important gold occurrences (including the Doyon gold mine, the Westwood mine and the former Bousquet mines) and has been traced for over ten kilometres within the Blake River Group, from the LaRonde mine westward to the Mouska gold mine.

Mineralization
The LaRonde deposit is a gold-rich volcanogenic massive sulphide deposit. LaRonde lenses were formed mainly by sulphide precipitation from hydrothermal fluids on the seafloor and by replacement below lenses. The stacking of the LaRonde lenses is the result of successive volcanic events, intercalated by cycles of hydrothermal activity associated with reactivation of synvolcanic faults.

The gold-bearing zones at the LaRonde mine are lenses of disseminated stringers through to massive aggregates of coarse pyrite with zinc, copper and silver content. Ten zones that vary in size from 50,000 to 40 million tonnes have been identified, of which four are (or are believed to be) economic. Gold content is not proportional to the total sulphide content but does increase with copper content. Gold values are also higher in areas where the pyrite lenses are crosscut by tightly spaced north-south fractures.

These historical relationships, which were noted at LaRonde Shaft #1’s Main Zone, are maintained at the Penna Shaft zones. The zinc-silver (i.e., Zone 20 North) mineralization with lower gold values, common in the upper mine, grades into gold-copper mineralization within the lower mine. The predominant base metal sulphides within the LaRonde mine are chalcopyrite (copper) and sphalerite (zinc).

The Company believes that Zone 20 North is one of the largest gold bearing massive sulphide mineralized zones in the world and one of the largest known mineralized zones in the Abitibi region of Ontario and Quebec. Zone 20 North contains the majority of the mineral reserves and mineral resources at the LaRonde mine, including 9.4 million tonnes of proven and probable mineral reserves grading 6.92 grams of gold per tonne, representing 86% of the total proven and probable mineral reserves tonnes at the LaRonde mine, 2.4 million tonnes of indicated mineral resources grading 4.52 grams of gold per tonne gold, representing 37% of the total measured and indicated mineral resources tonnes at the LaRonde mine, and 0.9 million tonnes of inferred mineral resources grading 8.11 g/t gold, representing 57%of the total inferred mineral resources tonnes at the LaRonde mine.

Zone 20 North extends from 700 metres below surface to at least 3,700 metres below surface, and remains open at depth. With increased access on the lower levels of the mine (i.e., below Level 245 and from the internal shaft on levels 257 and 278), the transformation from a zinc/silver orebody to a gold/copper deposit was effectively completed in 2017. The development of the West mine area, between Levels 278 and 314, provided access to a new zinc/silver rich sector beginning at the end of 2017.

Zone 20 North can be divided into an upper zinc/silver enriched gold poor zone and a lower gold/copper enriched zone. The zinc/silver zone has been traced over a vertical distance of 1,700 metres and a horizontal distance of 570 metres, with thicknesses approaching 40 metres. The gold/copper zone has been traced over a vertical distance of over 2,200 metres and a horizontal distance of 900 metres, with thicknesses varying from three to 40 metres. The zinc/silver zone consists of massive zinc/silver mineralization containing 50% to 90% massive pyrite and 10% to 50% massive light brown sphalerite. The gold/copper zone mineralization consists of 30% to 70% finely disseminated to massive pyrite containing 1% to 10% chalcopyrite veinlets, minor disseminated sphalerite and rare specks of visible gold. Gold grades are generally related to the chalcopyrite or copper content. At depth, the massive sulphide lens becomes richer in gold and copper.

Mining Methods

• Transverse open stoping
• Longitudinal retreat
• Longhole open stoping

Summary:

At the LaRonde Mine at the LaRonde Complex, based on the experience acquired by the Company since the beginning of the operation, longitudinal and transverse longhole open stoping are the main mining methods used for the extraction of the orebody. The longitudinal method is used for narrow ore widths above Level 215. The transverse mining method is the standard mining method for the operation below Level 215. This method is well adapted to address concerns regarding the high stress conditions encountered in the lower levels of the LaRonde Mine. Below Level 269, the distance between levels is maintained at 30 metres.

Different mining sequences are used to manage the stress front in the operation. The primarysecondary sequence is used with an overhand advance. An underhand mining method has been developed in the operation and it allows flexibility in accessing stopes without creating multiple sill pillars to achieve production. Combining overhand and underhand mining sequences creates a diamond-shaped mining front that helps push the stress away from the orebody to reduce the seismic risk. With the deepening of the mine, a pillarless sequence has been implemented in the abutments where the stress concentration nearby the stopes needed to be pushed back more progressively. The pillarless sequence consists of mining the stopes sequentially to remove the usage of temporary pillars, rather than a primary-secondary stope sequence. This mining sequence has been successfully used in overhand mining front since 2019. Starting in 2023, East Mine at depth is transitioning towards a pillarless mining sequence to reduce the seismic risk of the West underhand abutment. The pillarless sequence results in a longer cycle time when compared to the primary-secondary sequence, resulting in a reduced mining rate. However, this method reduces the seismic risk and promotes the sustainability of the operation in the long run.

Requirement for Development
LaRonde Mine
In LOM 2023, a total of 70.4 km of horizontal development will be required for the operation from 2023 to 2036, including 11.8 km planned in 2023. The annual amount of development until 2036 will be reduced progressively until the end of the operation. Vertical development is mainly to extend the intake and exhaust network by combining 16’ and 22’ diameter raises for the main network and 14’ diameter raises used for the escape way and delivery of fresh air to the level. In addition, smaller diameter raises ranging from 6’ to 8’ are used on specific occasions for secondary ventilation.

Backfill
All stopes at the LaRonde require backfill to maintain long term stability. Backfill is either an unconsolidated waste rock fill (“URF”) or consolidated paste backfill. URF is used in secondary transverse longhole stopes that will not be exposed to further mining. The consolidated pastefill is used in primary transverse longhole stopes and longitudinal longhole stopes which will be exposed to future mining.

The surface paste backfill plant has been designed to produce 200 tonnes of pastefill per hour. From the pastefill plant attached to the LaRonde mill, the backfill is delivered on a batch basis underground by a network of pipes and boreholes up to 6” in diameter to the selected empty stopes. Slag and cement are used as binder at a ratio of 80:20, respectively. The typical formulation has an average of 6% binder. For secondary stopes, waste rock is commonly used to fill the void (unconsolidated rock fill) and reduce the demand to hoist this material to surface.

Mining Fleet and Machinery
LaRonde Mine
The waste/ore material is mucked out with 8 yd3 or 11 yd3 scoops, dumped into 40-tonne or 50- tonne trucks and then transported up to the material handling system.

The system comprises two parts, with the first used for tonnage above Level 215. Trucks dump the waste/ore material in a silo above the crusher on Level 152. The crushed material, less than 4” in size, is linked at the Penna Shaft (Shaft #3) with a conveyor and then hoisted to surface.

In the second part below Level 215, the ore is brought to a network comprising two vertical silos close to the orebody with dump points at Level 284 and Level 290. These silos are linked and feed a coarse conveyor over 900 m to reach the crusher at Level 280 close to the Shaft #4 station. The crushed material (<4” in size) is then skipped via Shaft #4 and transferred to Shaft #3 via a conveyor. Finally, the material is skipped (vertically conveyed) to surface using Shaft #3.

The waste material is trucked to the silo near the station on Level 278 where it will be skipped by Shaft #4. The transfer of waste material from Shaft #4 to Shaft #3 is performed using trucks, and the waste material is then skipped to surface via Shaft #3.

Mine Ventilation LaRonde Mine
The LaRonde Mine is ventilated at 1,500,000 cubic feet per minute (“cfm”) with a network of 16’ and 22’ diameter raises (intake and exhaust) in a push-pull system. The system is located on surface with two fans at the intake (1,750 horsepower or “hp” each) and two fans at the exhaust (3,500 hp each). In addition, underground booster fans have been built during the operation extension on the exhaust side. A 6,000 hp booster fan is located on Level 194. Currently, two additional booster fans are being installed at Level 275 with capacities of 2,500 hp and 4,250 hp. They will be commissioned in 2023.

Mine Infrastructure
The LaRonde Mine was originally developed utilizing a 1,207-metre shaft (Shaft #1) and an underground ramp access system. The ramp access system is available down to Level 25 of Shaft #1 and continues down to Level 320 at the Penna Shaft (Shaft #3). The mineral reserves accessible from Shaft #1 were depleted in September 2000 and Shaft #1 is no longer in use. A second production shaft (Shaft #2), located approximately 1.2 km to the east of Shaft #1, was completed in 1994 to a depth of 525 m and was used to mine zones 6 and 7. Both ore zones were depleted in March 2000 and the workings were allowed to be flooded up to Level 6 (approximately 280 m depth). The Penna Shaft, located approximately 800 m to the east of Shaft #1, was completed down to a depth of 2,250 m in March 2000. The Penna Shaft is used to mine zones 20 North, 20 South, 21, 6 and 7.

In 2006, the Company initiated construction to extend the infrastructure at the LaRonde Mine to access the ore below Level 245. Hoisting from this deeper part of the LaRonde Mine began in the fourth quarter of 2011 and commercial production was achieved in November 2011. Access to the deeper part of the LaRonde Mine is provided through an 823-metre internal shaft (Shaft #4, completed in November 2009) starting from Level 203, for a total depth of 2,858 m from surface. A ramp is used to access the lower part of the orebody down to 3,200 m in depth. The internal winze system is used to hoist ore from depth to facilities on Level 215, approximately 2,150 m below surface, where it is transferred to the Penna Shaft hoist.

A cooling plant on Level 262 began operating in December 2013. This cooling system is necessary to reduce the frequency of heat-related delays experienced in prior years. In 2021, a new cooling plant on Level 308 (East mine) was put into operation. This cooling system was essential in order to reach Level 332 (East mine) and provide it with adequate temperatures for mining operations. To reach Level 335 (West mine), a new cooling system is planned on Level 308W which is expected to be operational in 2024.

The installation of a coarse ore conveyor system from Level 293 to the crusher on Level 280 was completed in September 2015. Starting in 2023, a dedicated haulage ramp will be operational starting from Level 317, going through 314W to end at the hammer 290 station to access the ore in Zone 20 North. The Company’s longer-term plan is to use automated trucks in this haulage ramp.

Comminution

Crushers and Mills

Summary:

Crushing
The ore is crushed underground with a jaw crusher. The opening is set at 4.5 inches. There is a standard installation for the grizzly with a hammermill feeding the jaw crusher.

Grinding
The grinding circuit begins with a truck dump linked by a conveyor gallery to a 5,000-tonne coarse ore bin. The coarse ore bin feeds a semi-autogenous grinding (“SAG”) mill in closed loops with hydrocyclones followed by a ball-mill circuit. The grind is determined by the secondary battery of hydrocyclones, and the target is fixed at P80 of 75 µm. The grinding circuit product is then sent to the copper flotation circuit. An expert system is operating the circuit.

Processing

• Column flotation
• Electric furnace
• Crush & Screen plant
• Carbon re-activation kiln
• INCO sulfur dioxide/air process
• Flotation
• Agitated tank (VAT) leaching
• Carbon in pulp (CIP)
• Elution
• Carbon adsorption-desorption-recovery (ADR)
• Dewatering
• Solvent Extraction & Electrowinning
• Filter press
• Cyanide (reagent)

Summary:

The LaRonde mill has a capacity of 7,200 tpd on a yearly basis, and processes ore containing precious metals (gold and silver) recovered by a carbon in pulp (“CIP”) process and ore containing base metals (copper, zinc and lead sulphides) recovered by a flotation process.

Copper flotation
For copper flotation, the first step is the rougher flotation and its product is sent to copper cleaning flotation with its reject sent to the next step at the zinc flotation. The rougher is composed of a flotation column to produce a part of the final copper concentrate followed by contact cell and mechanical cell that produces the primary concentrate to feed the cleaner stage with a maximum copper recovery. The copper cleaning flotation is necessary to obtain a salable copper concentrate by upgrading the copper content to 19.5%. It is composed of a first cleaner stage of tank cell and a second cleaner stage of contact cell. An expert system is operating the circuit by using data from camera and Courier6 (X-ray online).

Zinc flotation
The first step of zinc flotation is a rougher stage, and its product is sent to zinc cleaning flotation with its reject sent to the next step at the precious metal circuit. The rougher is composed by tanks cells to produce the primary concentrate to feed the cleaner stage with a maximum zinc recovery. The zinc cleaning flotation is necessary to obtain a salable zinc concentrate by upgrading the zinc content to 54%. It is composed of a first cleaner stage of mechanical cell, a second cleaner stage of flotation column and a third cleaner stage of flotation column. Circuit optimization is done using data coming from Courier6.

Leaching and CIP
The precious metals circuit processing the tails from the base metal flotation circuit consists of a leaching circuit, a CIP circuit and a refinery to pour gold doré. The leaching circuit consists of providing contact time between precious metals, oxygen and cyanide to lixiviate the gold and silver. A cyanide control system (“CCS”) ensures an optimum cyanide dosage along the leaching circuit. The CIP circuit provides time for the carbon to adsorb the gold onto the carbon. The configuration is a typical countercurrent system using Kemix screen and carbon transfer pump. The carbon concentration in tank is followed by probe (C2 meter) to optimize carbon transfer.

Stripping and electrowinning
The stripping and electrowinning process consists of chemically desorbing gold from carbon and onto plates for recovery. The carbon is sent to an acid wash column for removal of contaminants. After the acid wash, the carbon is moved to an elution column. A barren solution containing cyanide and caustic soda at a determined temperature and pressure will desorb gold from carbon and become the pregnant solution. The pregnant solution goes to the electrowinning circuit to plate the gold onto anodes. That solution is then returned to the barren solution and circulated to obtain the optimum stripping efficiency. The process was designed by Como Engineering at 8 Mt of carbon. The gold plating obtained from the electrowinning circuit is poured to produce doré.

Paste fill and cyanide destruction
The paste fill plant is in operation depending on the mining plan. The precious metal reject is sent to the cyanide destruction tank to undergo the INCO SO2/O2 process, and then thickened to obtain paste mixed with cement and slag based on a specific recipe. The Mine Engineering Department will create the recipe based on production database/mechanical resistance tests. The paste is then sent underground to the mined-out stopes for curing.

Residue filtration plant and preparation for dry stack
Construction of the dry stack mill was completed in 2022 with start-up in October 2022. The mill is situated after the tailing pump of the LaRonde and LZ5 mills, where they will feed a thickener of 36 metres. The overflow will go into the C5 cell and the pulp into two retention tanks (for 8 hours retention time). A vibrating screen will be installed to prevent large particles (>5 mm) from entering the filter press. The materials are pumped to the filter press to be dried by three filter presses (Outotec FFP3512) at a capacity of up to 10,000 tpd. The dry stack mill is designed to be adaptive to tonnage, which can vary depending on any mill shutdowns and on the pulp sent to the paste fill plant. After drying, material flows through a conveyor to a stockpile at the corner of the A4 tailing pond.

Pipelines and Water Supply

Summary:

Fresh water is sourced from Lac Chassignolle and is principally used in chemical preparation and in preparing paste fill to avoid the presence of sulphate in cement paste.

Water used in the LaRonde Mine’s operations is sourced from Lac Preissac/Chassignolle and is transported by pipeline over a distance of approximately 4 km.

Process water originates from the thickener prior to leaching and this process water is recirculated to the grinding circuit.

Reclaim water originates from basin #2 and is added throughout the circuit where additional water is required.

Tailings management area and water treatment plants
The water treatment infrastructure for the LaRonde Complex is located near the main tailings pond, and it includes the peroxy-silicate plant and the biological plant (final water treatment plant). The water pump station that recirculates water to the mill is located in the same area.

Water Management
The LaRonde Complex is recognized as a mining-industry leader in water treatment. After being pumped to the tailings pond, water is directed to Polishing Pond #1 before being sent to a water treatment plant for destruction of cyanide complexes and for metal precipitation with peroxide, silicate, lime and ferrous sulphate (WTP).

After lime precipitation in Polishing Pond #2, a water treatment plant using a biological process (FWTP) eliminates toxicity via the degradation of residual ammonia and thiocyanate. Commissioned in 2004, this plant can process more than 2 million m³ of water per year. All current provincial and federal limits are never exceeded. Some water originating from Polishing Pond #2 is sent to Polishing Pond #3B prior to mill usage.

The precipitation water in the area of the mills infrastructure and old waste rock pile #1 is sent to Pit #4 prior to the acid water treatment plant (AWTP).

The dewatering from the LaRonde Mine is sent to the main tailings pond prior to being sent to the water treatment plant (WTP, FWTP). The dewatering from the LZ5 Mine is sent to Pit #4 prior to being sent to the AWTP.

Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Buyer	Karly Szabadkai		Apr 2, 2024
Director of Operations	Christian Goulet		Apr 2, 2024
General Manager	Pascal Larouche		Apr 2, 2024
Metallurgical Superintendent	Jean-Sebastien L.		Apr 8, 2024
Mine General Superintendent	Yan Cabot		Apr 2, 2024