Amex Exploration's 2026 feasibility study for the Perron mine in Québec builds no process plant: all reserves are to be toll milled by cyanide leaching in week-long campaigns at a nearby mill.
The NI 43-101 Technical Report Feasibility Study for the Perron Mine, Québec, Canada, was prepared for Amex Exploration Inc. with an effective date of March 31, 2026 and issued on May 28, 2026. The study covers five years of commercial ore extraction, and all ore from the mineral reserves will be processed by toll milling. As a result, no processing plant or tailings storage facility is included in the project infrastructure.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Report effective date | March 31, 2026 | Not applicable | Feasibility study for Amex Exploration Inc. |
| Processing approach | Toll milling | Not applicable | No on-site plant or TSF |
| Mine production | About 1,100 | t/d | Average, five years |
| Average feed grade | 12.0 | g/t Au | Recovery assumption |
| Process type | Cyanide leach | Not applicable | More than 75% of gold gravity-recoverable |
| Leach feed grind | P80 100 | µm | Described as conservative |
| Sulphur content | 0.7 | % | Main composite |
| Predicted gold dissolution | 98.5 | % | From the Section 13 recovery equation |
| Allowances | 0.5 liquid tails, 0.5 ore handling | % | Losses at the toll mill |
| Overall gold recovery | 97.5 | % | Considered conservative by the QP |
Overview
The metallurgical testwork shows that Perron ore can be processed at several mills within a reasonable distance of the mine without particular issues, and that the testwork gives a selected mill all the information it needs to predict metallurgical performance, milling rate, reagent consumption and cost. Amex has held advanced discussions with several facility owners, and the qualified person considers an agreement for the five years possible.
The testwork shows that cyanide leaching gives the best recovery, and more than 75% of the gold could be recovered by gravity. The report notes that gravity reduces gold accumulation in dead areas, which helps security, but it does not improve recovery or significantly change treatment cost.
Key Process Stages
Campaign milling. The mine will deliver an average of about 1,100 t/d, and the toll mill is likely to have more capacity. Perron ore will therefore be stockpiled at the toll mill and treated in campaigns of at least one week, with Perron ore as the mill's only feed. The report says mixing feed from two companies is not acceptable, given how hard it is to sample gold grade precisely and the economic impact of an incorrect grade.
Grinding. The grinding requirement is a P80 of 100 µm, which the report calls common in most plants. A grindability test allows the P80 to be predicted as a function of throughput at any given mill.
Cyanide leaching. Gold recovery is by cyanide leaching at the toll mill.
Metallurgical balance. Each campaign needs a metallurgical balance based on gold produced, the change in mill gold inventory and gold lost to tailings, with sampling and assays at an independent laboratory. Amex will have a representative at the mill to witness sampling and assaying, and it has included provisions and assay fees for verification.
Additional Interesting Data and Summary
Gold recovery is estimated from an equation linking gold dissolution to head grade, leach-feed P80 and sulphur content. At 12.0 g/t, 100 µm and 0.7% sulphur it predicts 98.5% dissolution. After 0.5% losses to liquid tails and 0.5% to handling at the toll mill, the overall recovery is 97.5%, which the qualified person considers conservative and well suited to a feasibility study.
In summary, the Perron study relies on its high-grade, free-leaching ore and on third-party capacity: no plant is built, and campaign toll milling by standard cyanidation is expected to recover 97.5% of the gold. The report recommends sharing the full metallurgical results with the chosen mill so it can price the work accordingly.
Key Processes
- Ore haulage to a third-party mill
- Campaign toll milling
- Grinding to P80 100 µm
- Gravity-recoverable gold (more than 75%)
- Cyanide leaching
- Independent metallurgical balance per campaign
Source: NI 43-101 Technical Report Feasibility Study for the Perron Mine, Québec, Canada, prepared for Amex Exploration Inc., effective date March 31, 2026.
Earlier report summaries
Earlier versions of this profile, based on older technical reports, are retained below for source traceability. Dates and figures reflect each report’s own effective date and are superseded by the current information above.
Perron Project — 2025 Technical Report
The Preliminary Economic Assessment for the Perron Project defines a two-phase processing approach, beginning with toll milling and transitioning to an on-site carbon-in-leach plant.
Report context
The NI 43-101 Technical Report and Preliminary Economic Assessment for the Perron Project, Quebec, Canada, is dated October 17, 2025. The report presents a processing strategy comprising Phase 1 toll milling at 1,000 tonnes per day and Phase 2 on-site CIL plant operation at 2,000 tonnes per day commencing in year 5. Metallurgical test work was conducted by SGS Canada Inc. in 2020 and 2024 for Amex Exploration; no new metallurgical testing was performed specifically for the Preliminary Economic Assessment.
Processing route
Phase 1 , Toll milling
Bumigeme has identified four toll treatment plants within a 200 km radius capable of processing at least 1,000 tpd of head feed. The plants are designated by letters A, B, C, and D; Bumigeme has not contacted the companies holding these plants. Expected gold recoveries for each plant are as follows: Plant A (SAG Mill, Ball Mill, Gravity and CIL) 95%; Plant B (Rod Mill, Ball Mill, Gravity and CIP) 94%; Plant C (Rod Mill, Ball Mill, Gravity and CIL) 95%; Plant D (SAG Mill, Ball Mill, Gravity and CIL/CIP) 95%. Based on test work on Perron mineralization and the treatment processes studied, Bumigeme projects an average recovery rate of 95.0% for the toll treatment operation. During Phase 1, mineralized material will be transported from the mine site to the toll milling facility by a contractor using on-highway trucks. Amex Exploration assumes sole responsibility for negotiations with the management of the toll treatment plants.
Phase 2 , On-site CIL plant
The proposed process plant design for Phase 2 is based on a standard metallurgical flowsheet to treat gold bearing material at a rate of 2,000 tpd to produce doré. The flowsheet is based on metallurgical test work, industry standards, and conventional unit operations. Mineralized material will be sourced from underground mining (88%) and open pits (12%).
Primary crushing
Mineralized material from underground will be transported by 42-tonne haul trucks and from open pit by 37-tonne trucks. Run-of-mine mineralized material can be dumped into a 60-tonne feed hopper or placed on a stockpile when the crusher is idle or for blending purposes. A static grizzly screen is installed atop the hopper to remove oversized material, and a fixed rock breaker is used to break down oversized rocks. A 36-inch by 48-inch jaw crusher is fed by a vibrating grizzly feeder with a capacity of over 300 tons per hour. The primary crushing circuit is designed to reduce material size from minus 457 mm to minus 150 mm. The crusher operates for 12 hours per day, five days per week, 52 weeks per year, with 70% availability. A dust collector, self-cleaning magnet, and metal detector on the conveyor system prevent metal objects from reaching the storage dome.
Crushed mineralized material storage
Crushed mineralized material is conveyed to a dome stockpile providing 4,000 tonnes of live storage, sufficient for 48 hours of uninterrupted milling capacity. Material is withdrawn via three belt feeders, each 600 mm wide by 2 m long, with a capacity of 50–150 metric tonnes per hour, discharging onto a conveyor belt that feeds the SAG Mill.
Grinding circuit
The grinding circuit consists of a SAG Mill operating in open circuit followed by a ball mill in closed circuit with a cluster of hydro-cyclones. The SAG Mill is fed with material sized to 100% passing 150 mm. The SAG Mill may be powered by a variable speed drive to adjust for variations in material hardness. The ball mill grinds the material to 80% passing 74 µm. No tests are available to support the installation of a pebble crusher. Key elements include an 800 kW SAG Mill (5.5 m diameter by 1.8 m length, Asiatic Supplier), a 2,200 kW ball mill (4.5 m diameter by 6.1 m length, Asiatic Supplier), a cyclone cluster, and a 15 m diameter high-rate pre-leach thickener. Slurry from the SAG Mill discharges through a trommel screen; oversized material is collected in a trash bin and undersized material flows to the ball mill pump box. The ball mill discharges through a trommel screen with oversized material again collected. Water is added to the ball mill pump box to adjust slurry density for the cyclones. Cyclone overflow at 45% solids flows by gravity to a trash screen to remove wood and plastic chips, then proceeds by gravity to the pre-leach thickener. Thickener overflow is recycled as process water; underflow at 50% solids is pumped to the oxygenation and cyanidation tanks.
Gravity circuit
A QS30 Knelson concentrator, installed in the grinding circuit, recovers free gold from the cyclone underflow stream. A portion of the cyclone feed is diverted to the gravity circuit. Prior to entering the concentrator, the stream passes over a vibrating screen removing material coarser than 2 mm, which is returned to the grinding circuit. Undersized material feeds the centrifugal concentrator. Concentrates are discharged into a storage hopper and processed through a 1-tonne capacity Acacia intensive leach reactor. Tailings from the concentrator are routed back to the cyclone feed pump box. Acacia tailings are subsequently pumped to the ball mill pump box. A dedicated electrowinning cell is designated for treatment of the gold-rich pregnant solution from the intensive cyanidation unit.
Cyanidation and carbon adsorption
The milled product is thickened in the pre-leach thickener before entering the CIL circuit. The hybrid CIL circuit consists of one pre-aeration tank, one leach tank, and six adsorption tanks, each 10 m in diameter by 12 m high. The thickener underflow is pumped to the pre-aeration tank where process air is sparged for sulfide oxidation and lime is added for pH adjustment. Slurry then moves to the leach tank and through six agitated CIL tanks in series. Leaching is conducted using sodium cyanide with pH maintained at 10.5–11 via lime addition. All CIL tanks are sparged with process air. Slurry flows through the circuit via inter-stage pump screens; gold-loaded carbon is transferred counter-current to the slurry flow. Total residence time is 40 hours at a pulp density of 50% solids.
Gold recovery circuit
Loaded carbon from the CIL circuit is transferred to the elution circuit utilizing a standard pressure Zadra process. Loaded carbon undergoes acid washing and elution. Stripped carbon is reactivated in the carbon regeneration circuit before being returned to the CIL circuit. The pregnant strip solution is directed to electrowinning where gold sludge is collected and sent to a furnace for recovery as doré bullion.
Cyanide destruction
CIL tailings at approximately 45% solids flow by gravity to a carbon safety screen. Oversize material (recovered carbon) is collected for potential return to the CIL circuit; undersize material is pumped to two cyanide destruction tanks, each 8 m in diameter and 10 m high, providing total residence time of 4.6 hours. Cyanide destruction uses the SO₂/air process. Tanks are equipped with oxygen injection points and agitators.
Tailings thickening and disposal
Detoxified tailings are pumped to a 15 m diameter high-rate thickener to increase slurry density to 62–64% solids before being discharged into four empty pits. It is estimated that 50–60% of the water sent to the pits could be recovered and pumped back to the process water tank.
Reagent preparation and control systems
The plant is equipped with a reagent preparation and distribution system. Consumables include grinding balls (forged steel), pebble quicklime, hydrated lime, sodium cyanide, and flocculants. Processes are controlled by a SCADA automation system implemented through a redundant fiber optic PLC-based ring structure connecting all PLCs and E-Houses. Motor control centers feature Ethernet interfaces. The process plant building includes a laboratory, mill offices, a dry, and an electrical and mechanical shop.
Key reported parameters
| Parameter | Value | Unit | Basis |
|---|---|---|---|
| Phase 1 | |||
| Toll milling rate | 1,000 | tpd | Design |
| Expected gold recovery | 95.0 | % | Projected from testwork and plant flowsheets |
| Phase 2 | |||
| On-site CIL plant rate | 2,000 | tpd | Design |
| Average head feed grade | 4.27 | g/t | Design |
| Gold recovery (CIL) | 95 | % | Design estimate |
| Gold recovery by gravity | 35 | % | Design |
| Mill availability | 92 | % | Design |
| Milling rate | 90.6 | t/h | Design |
| Crushing rate | 334 | t/h | Design |
| Crushing size F80 | -457 | mm | Design |
| Crushing size P80 | -150 | mm | Design |
| SAG Mill power | 800 | kW | Design |
| Ball Mill power | 2,200 | kW | Design |
| Ball Mill grind size P80 | 74 | µm | Design |
| CIL retention time | 40 | h | Design |
| CIL pulp density | 50 | % | Design |
| Number of CIL tanks | 6 | Design | |
| Detoxification residence time | 4.6 | h | Design |
| Total electrical connected load | 5.1 | MW | Design |
| Operating demand load | 4.5 | MW | Design |
| Electricity consumption | 39.12 | kWh/t | Design |
| Total water requirement | 152.8 | m³/hr | Design |
| Fresh water requirement | 40.5 | m³/hr | Design |
| Recycled process water | 137.7 | m³/hr | Design |
| Testwork results | |||
| Gold recovery by gravity/cyanidation | Exceeding 95 | % | 2020 and 2024 SGS testwork |
Project website: https://www.amexexploration.com/properties/quebec-exploration-perron-property
Technical qualifications
Historical metallurgical test work was conducted by SGS Canada Inc. in 2020 and 2024 for Amex Exploration. No new metallurgical testing was performed specifically for the Preliminary Economic Assessment; all data relies on previous results detailed in Chapter 13. No tests are available to support the installation of a pebble crusher. Bumigeme has not contacted the companies holding the plants identified for toll treatment. Expected gold recoveries for toll treatment are based on review of each plant flowsheet and historical testwork, not on direct plant testing with Perron material.
Source: NI 43-101 Technical Report, Preliminary Economic Assessment, Perron Project, Quebec, Canada, October 17, 2025, Sections 1.17, 17.1–17.13.
