The 2019 technical report describes the proposed processing facilities for the Whabouchi spodumene concentrator and the Shawinigan electrochemical plant, with design criteria based on testwork.
Report context
The February 2018 NI 43-101 technical report on the feasibility study for the Whabouchi Lithium Mine and Shawinigan Electrochemical Plant, issued by Nemaska Lithium Inc., presents the recovery methods and process design for the two integrated facilities. The Whabouchi concentrator is located 675 m north east of the open pit mine. The Shawinigan Electrochemical Plant is located in the City of Shawinigan, Quebec. The report documents proposed design parameters, historical testwork results, and the basis for process flow sheets and mass balances.
Processing route
Whabouchi Concentrator
Crushing and ore sorting
The concentrator is designed to produce a nominal 215,022 tonnes of spodumene concentrate per year at 6.25% Li₂O from an ore feed averaging 1.53% Li₂O. The run-of-mine mineralized material, containing 19.1% spodumene with 2% moisture, is dumped into a hopper and fed via apron feeder into a jaw crusher. The primary crusher discharge, with P80 of 95 mm, is screened on a double deck coarse ore screen. Top deck oversize is returned to a second jaw crusher in closed circuit. Bottom deck oversize (−80 mm +10 mm) is conveyed to ore sorters operating by X-Ray Transmission identification. The ore sorting area screens the feed at 35 mm; coarse ore sorter feed is −80 mm +35 mm and fine ore sorter feed is −35 mm +10 mm. Rejected waste is stockpiled for removal, while accepted material is transported to the fine crushing facility.
Fine crushing comprises a double deck vibrating screen and a two-stage cone crusher circuit. Secondary cone crushers (standard) crush top deck oversize to P80 of 21 mm; a tertiary short head cone crusher crushes bottom deck oversize to P80 of 12.7 mm. The final crushed product, with P80 of 5.8 mm and 100% passing 9 mm, is conveyed to a fine ore stockpile in a dome.
Dense media separation
The fine ore is screened on a double deck vibrating screen with 2.0 mm top deck and 0.85 mm bottom deck openings. Screen undersize (−0.85 mm) bypasses the DMS system to the fine muscovite removal circuit. Oversize (−9.0 mm +0.85 mm) goes to coarse muscovite removal via a hydraulic separator. The hydraulic separator overflow is screened; oversize reports to final tailings, while underflow and screen undersize are pumped via a dewatering screen to the DMS feed bin.
The DMS circuit uses a two-stage dense media separator unit. The rougher stage consists of two 510 mm diameter cyclones operating at a cut point specific gravity of 2.70, producing rougher floats (DMS tailings) and rougher sinks. The cleaner stage uses one 510 mm diameter cyclone at a cut point specific gravity of 2.96, producing cleaner floats (DMS middlings) and cleaner sinks (DMS concentrate). The DMS concentrate is dried in a rotary dryer to less than 1% moisture, then treated by dry magnetic separation (low intensity followed by rare earth high intensity) to produce the first portion of final spodumene concentrate at above 6.6% Li₂O.
Grinding and flotation
The DMS middlings are ground in a 2.4 m diameter by 2.7 m EGL grate discharge ball mill (250 kW) to a P80 of 640 µm, then combined with fine ore screen undersize for fine muscovite removal. The ground product feeds cyclones for densification, then a hydraulic separator for fine muscovite removal. Desliming is performed in a cyclone cluster, followed by wet magnetic separation (low intensity at 950 Gauss and wet high intensity at 13,000 Gauss) to remove paramagnetic material.
The spodumene flotation circuit consists of de-sliming, attrition scrubbing, and two stages of flotation. Attrition scrubbing uses four cells of 2.5 m³ each with dispersant and caustic soda at pH 12. Coarse flotation (−850 µm +200 µm) is performed in a 1.8 m diameter by 3.7 m high HydroFloat separator after conditioning with sulfuric acid (pH 8) and spodumene collector. The HydroFloat concentrate is screened at 250 µm; oversize at 5.52% Li₂O goes to the concentrate dewatering circuit.
Fine flotation (−200 µm +20 µm) uses two 2.5 m diameter by 8.0 m high flotation columns (rougher and cleaner) after conditioning with sulfuric acid (pH 8) and spodumene collector. The rougher column tailings go to the tailings thickener; rougher concentrate feeds the cleaner column. Cleaner column concentrate grades 6.37% Li₂O. Cleaner tailings are recycled to the de-sliming cyclones.
Concentrate dewatering and tailings
The flotation concentrate is thickened to 62% solids in a 6.0 m diameter high rate thickener, then filtered to less than 8% moisture using a 350 m² vertical plate pressure filter. The filtered concentrate combines with dried DMS concentrate on a conveyor; the blended concentrate has expected moisture less than 5%. The combined product is stored in a 4-day concentrate stockpile dome, then transported by road truck to Chibougamau for rail transport to Shawinigan.
Tailings from DMS, dry magnetic separation, mica hydroseparation, de-sliming, wet magnetic separation, HydroFloat, and column flotation are dewatered by a combination of screen dewatering, thickening in a 10.6 m diameter inclined plate settler to 61% solids, and pan filtration to 15% moisture. Filtered tailings are stored in a 1-day tailings storage dome and transported by haul truck to the co-disposal area with mine waste.
Concentrator mass balance and water
The concentrator processes 2,824 dry tonnes of ore per day requiring 279 m³/d of makeup water. Tailings are dewatered to about 12% moisture for dry stacking. The concentrator operates at 92% availability; the DMS section at 80%; the crusher at 66.7%. The DMS circuit recovers 36.7% of total feed spodumene; the flotation circuit recovers 48.6%; total spodumene recovery is 85.3%. DMS concentrate production is 86,641 dry tonnes per year; flotation concentrate production is 128,432 dry tonnes per year.
Shawinigan Electrochemical Plant
Plant design and feed
The electrochemical plant is designed for a feed rate of 215,022 dry tonnes per year of spodumene concentrate (42% DMS concentrate, 58% flotation concentrate) to produce 33,000 tonnes per year of lithium carbonate equivalent (LCE). The plant can vary lithium hydroxide monohydrate production from 50% to 100% of total Li units and lithium carbonate powder from 0% to 50% of total Li units. The plant operates 24 hours per day, 7 days per week, with 85% availability.
Thermal conversion and acid bake
Concentrate arrives by 92-tonne railcars, is discharged into a receiving hopper, and conveyed to a stockpile. A front-end loader reclaims concentrate through a crushing system reducing top size from 9.5 mm to less than 2 mm, then to a concentrate silo with 18 hours live capacity. The concentrate is preheated in three pre-heating cyclones, then calcined at 1,000 to 1,100°C in a natural gas fired flash calciner to convert alpha-spodumene to beta-spodumene. The roasted concentrate is cooled in cooling cyclones and a water-cooled indirect cooler, then stored in a roasted concentrate silo. Hot flue gases are sent to a baghouse for dust removal.
Beta-spodumene is mixed with sulfuric acid in a pug mixer and sent to an acid-bake kiln. The heat allows reaction of oxides with sulfuric acid to produce sulfates, primarily lithium sulfates and minor amounts of select impurity sulfates.
Leaching, purification, and electrolysis
The acid bake product is mixed with water in the concentrate leach step, then separated on a belt filter to remove gangue (aluminum-silicate). The pregnant leach solution undergoes three purification and filtration steps: primary impurity removal, secondary impurity removal, and tertiary impurity removal, followed by ion exchange polishing to remove trace calcium. These steps remove excess acid, calcium, silicon, iron, aluminum, manganese, and magnesium.
The polished solution feeds electrolyzers where lithium sulfate is converted to lithium hydroxide (catholyte solution) and sulfuric acid (anolyte solution). The anolyte is sent to sulfuric acid concentration and recycled to the pug mixer with fresh make-up acid.
Crystallization and final products
The catholyte is sent to lithium hydroxide monohydrate (LHM) crystallization. A double crystallization process produces pure LHM crystals and condensate that is fully re-used. A small bleed stream from LHM crystallization is sent to treatment where lithium is recovered and sodium and potassium are purged. LHM crystals are dried for sale. Up to 50% of LHM crystals can be converted to lithium carbonate in a dedicated circuit for sale as final product. Overall lithium recovery is reported as 95.9%.
Key reported parameters
| Parameter | Unit | Value | Basis |
|---|---|---|---|
| Total ore processing rate (Whabouchi) | dry t/y | 1,030,831 | Design |
| Average ore processing rate | dry t/d | 2,824 | Design |
| Spodumene ore grade | % Li₂O | 1.53 | Design |
| Final spodumene concentrate grade | % Li₂O | 6.25 | Design |
| Total spodumene recovery (concentrator) | % | 85.3 | Testwork |
| DMS weight recovery | % | 8.4 | Design |
| Flotation weight recovery | % | 12.5 | Design |
| Total weight recovery | % | 20.9 | Testwork |
| DMS concentrate production | dry t/y | 86,641 | Design |
| Flotation concentrate production | dry t/y | 128,432 | Design |
| Total spodumene concentrate production | dry t/y | 215,022 | Design |
| Concentrator operating availability | % | 92.0 | Design |
| DMS circuit availability | % | 80.0 | Design |
| Concentrate composition (DMS/flotation) | % | 42 / 58 | Design |
| Electrochemical plant feed rate | dry t/y | 215,022 | Design |
| Overall plant availability (electrochemical) | % | 85 | Benchmark |
| LHM average production | t/y | 24,500 | Design |
| LHM product grade | % LiOH | ≥57.5 (<20 ppm Na) | Design |
| Lithium carbonate average production | t/y | 11,500 | Design |
| Lithium carbonate product grade | % Li₂CO₃ | ≥99.5 | Design |
| Overall lithium recovery (electrochemical) | % | 95.9 | Laboratory results/modeling |
| Spodumene concentrate F100 | microns | 9,500 | Design |
Project website: https://www.mccarthy.ca/en/experience/nemaska-lithium-seeks-additional-funding-for-lithium-mine-and-transformation-plant
Technical qualifications
The process design and criteria are based on a feasibility study prepared for Nemaska Lithium Inc. The overall lithium recovery for the electrochemical plant is based on laboratory results and extensive mass balance modeling. The concentrator weight recovery of 20.9% and spodumene recovery of 85.3% are average figures based on testwork on representative samples. Plant availability of 85% for the electrochemical plant is estimated based on benchmarks with comparable industries and high-level availability analysis. The report states that as of the date of the technical report, no commercial off-take agreements for concentrate sales were in place; two commercial off-take agreements for LCE products totalling about 14,000 LCE were in place, valid between 42 and 60 months from start of commercial production.
Source: Nemaska Lithium Inc., NI 43-101 Technical Report – Feasibility Study on the Whabouchi Lithium Mine and Shawinigan Electrochemical Plant, February 2018.
Consolidated report summaries
The following former standalone pages about this operation were consolidated here on October 25, 2026. They are retained for source traceability; dates and figures reflect each report’s own effective date and may be superseded by the current information above.
Whabouchi Mine Project — 2023 Technical Report
The Whabouchi concentrator, located 675 m northeast of the open pit, applies crushing, ore sorting, dense media separation, grinding, and flotation to produce a 5.5% Li₂O spodumene concentrate, with the processing design updated in phases since 2014.
Report context
The Whabouchi Mine Project technical report dated 2023, NI 43-101 Technical Report – Nemaska Whabouchi Mine Project – Nemaska, Quebec, describes the processing facilities for the spodumene operation. The process design is split between the concentrator near the open pit and a planned conversion plant in Bécancour. This article covers the concentrator flowsheet, equipment selection, and the reported process design basis, drawing on Section 17 of the report.
Processing route
Crushing and ore sorting
Run-of-mine (ROM) material is dumped into a ROM stockpile, rehandled by front-end loader, and transferred to a ROM feed hopper equipped with a static grizzly and rock breaker. An apron feeder withdraws material to a primary jaw crusher (1,000 mm × 1,300 mm, 160 kW) with a P80 of 95 mm. A triple-deck vibrating screen classifies the crushed ore. The top deck oversize (+80 mm) is sent to a secondary jaw crusher (800 mm × 1,150 mm, 132 kW). Screen middle deck oversize (80+35 mm) reports to a coarse ore sorter, while bottom deck oversize (35+10 mm) reports to a fine ore sorter. The screen undersize (-10 mm) bypasses sorting to fine crushing.
Ore sorting uses X-Ray Transmission (XRT) sensors. The coarse ore sorter feed is -80+35 mm; the fine ore sorter feed is -35+10 mm. Sorting rejects an estimated 10-15% of feed, with design capacity for instantaneous rejection rates near 30%. A future scavenger ore sorter is planned to be operational in year 5. The fine crushing circuit comprises a double-deck vibrating screen (top deck 20 mm, bottom deck 9 mm), two secondary cone crushers (P80 21 mm), and one tertiary short head cone crusher (P80 12.7 mm), all in closed circuit to produce a final crushed product with P80 5.8 mm.
Dense media separation
The DMS circuit is a two-stage system: a rougher stage with one DMS cyclone and a cleaner stage with one DMS cyclone. Feed is prepared by screening on the fine ore screen (top deck 2.7 mm, bottom deck 0.85 mm). Screen oversize reports to a coarse muscovite removal hydraulic separator, with screen undersize sent to fine muscovite removal. Ferrosilicon is used as the dense medium, with circulating and dilute media circuits; low intensity magnetic separators and densifying cyclones recover ferrosilicon for reuse.
The rougher floats become DMS tailings. The rougher sinks are cleaned, with cleaner floats (middlings) sent to the ball mill and cleaner sinks as DMS concentrate. The DMS concentrate is dried in a rotary dryer to below 1% moisture for dry magnetic separation. Magnetic separation includes a low intensity stage followed by a rare earth high intensity stage. Final DMS concentrate grade is approximately 6.0% Li₂O.
Grinding and classification
DMS middlings are ground in a ball mill in closed circuit with a screen with 850 μm apertures. The screen undersize, at P80 640 μm, combines with fine ore screen undersize for fine muscovite removal. A cyclone cluster densifies the slurry; overflow is screened at 212 μm, with screen oversize (mostly muscovite) sent to tailings.
Fine muscovite removal and desliming
The fine ore screen undersize and ball mill product are pumped to a cyclone. Cyclone underflow is introduced into the fine muscovite removal hydraulic separator. Overflow containing muscovite and particles finer than 200 μm is screened at 212 μm, with screen oversize sent to tailings. The underflow is mixed with screen undersize and pumped to a cyclone cluster for de-sliming; overflow is rejected to tailings.
Wet magnetic separation and attrition scrubbing
Magnetic separation is performed in two stages: first, a Low Intensity Magnetic Separator (LIMS) removes residual dense media and steel from the ball mill; second, a Wet High Intensity Magnetic Separator (WHIMS) removes paramagnetic material from flotation feed. Non-magnetic products feed a densifying cyclone cluster that removes additional slimes and densifies the attrition scrubber feed.
Attrition scrubbing is performed at high pulp density with high shear mixing. A dispersant is added to loosen tenacious fine particles, and caustic soda raises pH to 12. The attrition scrubber discharges to a hydraulic separator with a cut size of 200 μm. Underflow feeds the coarse particle flotation circuit; overflow goes to a third desliming stage.
Spodumene flotation
The hydraulic separator underflow is sent to the hydroflotation split-feed vibrating screen. Screen oversize (+500 μm) goes to ultracoarse conditioning tanks, while undersize is densified in a cyclone before coarse conditioning. Both circuits use four stages of high-density conditioning with spodumene collector and sulfuric acid to achieve pH 8.
Hydroflotation uses Eriez HydroFloat separators. The ultracoarse and coarse hydroflotation concentrates are combined and screened at 210 μm. Screen undersize is recycled to column flotation; screen oversize, grading approximately 4.1% Li₂O, reports to the concentrate holding tank. Coarse hydroflotation underflow goes to tailings; ultracoarse underflow is screened at 600 μm, with oversize recycled to the ball mill and undersize sent to tailings.
The column flotation circuit has three flotation columns: rougher, scavenger, and cleaner. Rougher concentrate is pumped to the cleaner column; rougher tailings go to the scavenger column. Scavenger concentrate is recirculated to the 3rd desliming cyclone cluster; scavenger tailings go to tailings. Cleaner concentrate is final concentrate at approximately 5.1% Li₂O, with cleaner tail recycled to the 3rd desliming cyclone pump box.
Concentrate dewatering and handling
Hydroflotation concentrate screen oversize is sent directly to the concentrate holding tank. Column flotation concentrate is thickened to 62% solids in a high-capacity thickener. Combined flotation concentrate is filtered to approximately 8% moisture on a vacuum belt filter. The filtered concentrate is combined with dried DMS concentrate and conveyed to a covered concentrate stockpile with approximately 41 hours capacity. The combined concentrate is expected to have 4% moisture, is rehandled by front-end loader into containers on trucks for shipment to Matagami, then by rail to the conversion plant.
Tailings dewatering and storage
Coarse tailings are screened and discharged onto the final tailings conveyor. Fine tailings are thickened in an inclined plate settler to 61% solids, then filtered to 15% moisture using a vacuum belt filter. Combined tailings at 12% moisture are conveyed to a loadout bin with emergency stockpile, then transported by mine trucks to the on-site filtered tailings storage facility (CSF).
Expansion allowances
A Phase 1 expansion to increase production by 11.5% has not been defined in detail. A debottlenecking evaluation will be performed during operation, expected to require additional capacity in DMS, grinding, and dewatering. An allowance is included in sustaining capital for Phase 1 and a potential Phase 2 expansion in year 24 as the mine transitions from open-pit to underground.
Key reported parameters
The table below summarizes the process design basis, distinguishing the 2019 design (6.25% Li₂O) from the updated design (5.5% Li₂O) for three production periods.
| Parameter | Units | 2019 Design | Average Years 1-6 | Average Years 7-24 | Average Years 25-34 |
|---|---|---|---|---|---|
| Annual ore processing rate | dry t/y | 1,030,831 | 963,230 | 1,152,518 | 1,243,024 |
| Average ore processing rate | dry t/d | 2,824 | 2,639 | 3,158 | 3,406 |
| Spodumene ore grade (Li₂O) | % | 1.53 | 1.31 | 1.33 | 1.29 |
| Overall lithium recovery (sorting + concentrator) | % | 85.2 | 83.0 | 84.3 | 81.9 |
| Spodumene concentrate grade | % Li₂O | 6.25 | 5.50 | 5.50 | 5.50 |
| Annual spodumene concentrate production | dry t/y | 205,000 | 190,252 | 234,473 | 238,841 |
| Daily spodumene concentrate production | dry t/d | 562 | 521 | 642 | 654 |
| DMS circuit operating time | % | 80.0 | 80.0 | 80.0 | 80.0 |
| Concentrator effective availability | % | 92.0 | 85 | 85 | 85 |
Project website: https://nemaskalithium.com/en/the-whabouchi-mine/
The design daily ore throughput is 2,639 tonnes requiring 221 m³/d of makeup water. Most water is lost in tailings at about 12% moisture for dry stacking in a CSF with waste rock. The average ore processing rate for years 1-7 is 963,230 dry tonnes per year at a feed grade of 1.32% Li₂O, producing 190,252 dry tonnes per year of 5.5% Li₂O concentrate.
For years 1-7, DMS recovers 8-11% by weight while flotation recovers 12-14% by weight, for a total of 21-24% weight recovery depending on year. Annual production figures are based on an effective concentrator availability of 85%. The mass balance table in the report shows 2,638.1 dry t/d of spodumene ore entering the concentrator with total mass 2,917.1 t/d, and 549.9 t/d of final concentrate exiting (including 22.2 m³/d water).
The current design targets a 5.5% Li₂O spodumene concentrate from ore averaging 1.32% Li₂O, equivalent to 68.5% spodumene (LiAlSi₂O₆). The concentrator design factors are 30% for crushing equipment, 15% for most concentrator equipment, and 5% for slurry pumps.
Technical qualifications
The report identifies several limitations on the process design. The target availability of 91.5% is considered optimistic by the qualified person, with an upper limit potentially as low as 75-85%, or recovery may decrease to maintain concentrate production. An effective availability of 85% was used for design production profiles. The 2019 design assumed 91.5% effective availability, producing at lower throughput for the same annual production.
The report notes the flowsheet is complex and constrained by existing procured equipment, the erected building, and half-constructed plant. Following 2021 modifications, design factors across the process plant are no longer systematic, with an increased risk of bottlenecking on equipment with low design factors. Ramping up to target production values may take longer than anticipated and may require additional sustaining capital projects.
Concentrate production and recovery estimates are based on individual stage recoveries from bench and pilot scale work compiled into a metallurgical model; this estimate has not been confirmed through full pilot plant testing, which is not required at a Pre-Feasibility Study level. The Phase 1 expansion has not been defined, and the Phase 2 expansion is an allowance only.
Source: NI 43-101 Technical Report – Nemaska Whabouchi Mine Project – Nemaska, Quebec, Sections 13, 17 and Table 17-1 through 17-3.
