The North American Lithium (NAL) project in Québec, Canada, owned by Elevra (with Sayona Inc. as the issuer), is an operating spodumene concentrate producer pursuing a staged expansion. The expansion is designed to increase processing rates and improve lithium recovery through targeted upgrades to the existing concentrator.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Current authorized production | 4,500 | tpd | Average annual rate for processing plant |
| Stage 1 concentrate production increase | 15-20 | % | Within existing 4,500 tpd permit |
| Stage 2 milling throughput | 6,500 | tpd | Average annual rate post-expansion |
| Stage 3 crusher circuit | New | Not applicable | Milling capacity unchanged from Stage 2 |
| Plant feed Li₂O grade (design base case) | 1.01 | % | Source material does not specify if design or test result |
| Plant feed Li₂O grade (Stage 1 design) | 1.095 | % | |
| Plant feed Li₂O grade (Stages 2 and 3 design) | 1.080 | % | |
| Target concentrate Li₂O grade | 5.40 | % | All stages |
| Target concentrate production (Stage 1 design) | 213,670 | tpa | |
| Target concentrate production (Stage 2 design) | 338,000 | tpa | Note 1: financial model uses different rates |
| Target concentrate production (Stage 3 design) | 338,000 | tpa | Same as Stage 2 |
| Concentrate P80 (base case, Stages 2 and 3) | 0.200 | mm | |
| Concentrate P80 (Stage 1) | 0.232 | mm | |
| Processing plant availability | 90 | % | All stages |
| Crushing plant availability | 65 | % | All stages |
| Lithium recovery (design) | 71.20 | % | Anticipated; based on improvements to current 69.00% |
| Final concentrate moisture content | 6 | % | After dewatering |
| Desliming cyclone cut point (D50) | 10 | µm | Target |
Overview
The recovery methods for the NAL expansion were developed from the existing plant's operational history, historical metallurgical testwork, and lessons learned from other spodumene projects. The expansion process design draws on operational and metallurgical reviews of past plant operation and testwork data.
NAL's current operations are authorized at 4,500 tpd average annual production for the processing plant to produce spodumene concentrate. The existing facility includes primary, secondary and tertiary crushing, and ore sorting circuits on the run-of-mine material to produce upgraded plant feed. The spodumene processing plant includes grinding, desliming, magnetic separation, flotation and dewatering circuits. Process water and utilities circuits include tailings thickeners, reagents preparation, reverse osmosis treatment, and tailings management.
The processing plant also includes an area for converting spodumene concentrate into lithium carbonate, but that area is currently not in operation. Elevra has indicated there are no plans to produce lithium carbonate at the NAL facility.
The expansion follows a staged approach. Stage 1 targets a 15 to 20 percent increase in spodumene concentrate production within the existing 4,500 tpd permit. Stage 2 expands to a milling throughput limit of 6,500 tpd average annual rate. Stage 3 adds a new crusher circuit with milling capacity unchanged from Stage 2.
The targeted capacities will be achieved through specific modifications. Stage 1 includes adding lump breakers in the ore feed circuit, increasing stacksizer capacity to the existing ball mill circuit, optimizing desliming and magnetic separation, increasing flotation conditioning capacity, refurbishing the carbonate filtration unit for new spodumene dewatering and filtration, replacing the existing thickener with a larger process thickener, adding a flotation thickener circuit, and reconfiguring tailings pumping. Stage 2 includes contracting a temporary crusher, adding a second rod mill and ball mill line circuit with stacksizers, adding a trash screen to remove oversize material before magnetic separation, adding a third magnetic separation line, and adding a new rougher unit with conversion of the existing rougher to scavenger duty. Stage 3 includes constructing a new crusher, constructing a new fine covered ore stockpile, and converting the existing crusher circuit to an ore sorting facility.
Key Process Stages
Stage 1 Description
The existing crusher will continue regular operations during Stage 1. Crusher capacity is expected to increase to meet the 15 to 20 percent concentrate production increase without any expansion. Due to reported issues with ice lumps forming in the fine ore silo from cold weather conditions, lump breakers will be installed at the silo outlets ahead of the plant feed conveyor.
Fine ore feeds from the fine ore silo to the grinding circuit via the plant feed conveyor. The existing grinding circuit consists of a rod mill and ball mill circuit with six stacksizers. Three additional stacksizers are added to improve milling circuit performance. The combined rod mill and ball mill discharge reports to the stacksizers, with oversize returned to the ball mill.
Stacksizer undersize goes to a new primary desliming cyclone targeting a cut point of 10 µm. Overflow reports to the process thickener. Primary desliming cyclone underflow goes to a new magnetic separation circuit with two lines, each including a low-intensity magnetic separator and a primary wet high-intensity magnetic separator. The intermediate non-magnetic product from both lines combines and goes to parallel secondary WHIMS that are existing and repurposed. Magnetics from all stages combine and pump to the process thickener.
Non-magnetic slurry from the secondary WHIMS feeds a new secondary desliming cyclone to reach 65 percent solids in the underflow. Cyclone overflow returns to the primary desliming cyclone in Stage 1. Underflow reports to rougher conditioning. Converting the existing dilution tank into a new conditioning tank enables two-stage rougher conditioning when combined with the existing high-density rougher conditioning tank. The conditioned slurry is diluted and fed to the existing rougher flotation circuit.
Rougher tails are further deslimed in a cyclone and conditioned before scavenger flotation. The scavenger dilution tank is converted to conditioning duty for two-stage conditioning similar to the rougher circuit. Scavenger tails go to the flotation thickener. Concentrate from rougher and scavenger circuits combines and goes to cleaner 1 flotation. Cleaner flotation tails go to a new classifier cyclone with underflow returned to the grinding circuit and overflow to the flotation thickener.
Cleaner concentrate pumps to a new concentrate storage tank serving as buffer between upstream processing and downstream dewatering and filtration. The new dewatering unit consists of a concentrate dewatering cyclone and a concentrate scavenger cyclone. The scavenger cyclone recovers misreporting material from the dewatering cyclone and vacuum filters.
The new filtration unit consists of parallel vacuum belt filters operating as one duty and one standby. These are refurbished lithium carbonate filters existing in the plant. Spodumene concentrate dewaters to a final moisture content of 6 percent. The existing filter unit is bypassed but not dismantled.
Final 5.4 percent spodumene concentrate stores in a new enclosed stockpile located where the carbonate calciner will be dismantled. The stockpile has capacity for approximately 200 hours in Stage 1 and includes truck access for product loading.
The processing plant operates with new separate process water and flotation water circuits. This design isolates water contaminated with flotation reagents from sensitive equipment such as the LIMS and WHIMS. The existing thickener is bypassed but not dismantled. The process water circuit has a single thickener receiving slimes from primary desliming and magnetic material from magnetic separation. The flotation water circuit has a single thickener receiving cyclone overflow from cleaner classification, scavenger flotation tailings, and scavenger concentrate dewatering cyclone overflow. Thickener underflow from both thickeners combines in a tank and pumps to the tailings storage facility through two parallel pipelines.
Stage 2 Description
The existing crusher continues regular operations during Stage 2. A temporary contract crusher is added to balance the requirements of the processing plant after expansion to 6,500 tpd. The contract crusher feeds the emergency ore stockpile.
A new grinding circuit with rod mill and ball mill is added. The transfer conveyor from the emergency ore stockpile extends to feed a new line of conveyors. The second grinding circuit feeds uniquely from the emergency stockpile until a permanent solution is installed in Stage 3. Feed from the fine ore silo for the existing line remains unchanged. Total fine ore fed to the grinding circuit via conveyor reaches 6,500 tpd through a combination of the existing crusher and temporary contract crusher.
Fine ore feed to the existing and new grinding circuits follows a 50/50 ratio. The new grinding circuit includes a larger ball mill than the existing one to allow further capacity increases in the future. The new grinding circuit includes six stacksizers. A future expansion to reach 200 tph in the new ball mill would require additional stacksizers.
Stacksizer undersize from both grinding circuits collects and screens through a new trash screen to remove product over 1 mm. Screen undersize goes to the primary desliming cyclone as in Stage 1. The cyclone is installed in Stage 1 but sized for Stage 2 capacity.
Primary deslime cyclone underflow goes to the magnetic separation circuit as in Stage 1. A new third line of LIMS and primary WHIMS is added for increased capacity. The intermediate non-magnetic product from all three lines combines and goes to two parallel secondary WHIMS as in Stage 1. Final non-magnetic slurry collects and goes to the new rougher flotation circuit. Magnetics from all stages combine and pump to the process thickener.
Non-magnetic slurry feeds a new secondary desliming cyclone to reach 65 percent solids in the underflow. Cyclone overflow returns to the trash screen. Secondary deslime cyclone underflow goes to new two-stage rougher conditioning tanks followed by a new rougher flotation circuit. The first step of rougher flotation uses two cells in parallel with individual cell level control. Tails from the first stage go to the second step of rougher flotation. Concentrate from both stages goes to cleaner 1 flotation. The design allows the first step of rougher flotation to bypass directly to cleaner 2 or cleaner 3. Tails from the new rougher flotation go to the scavenger unit.
With the new rougher flotation circuit added in Stage 2, the Stage 1 rougher circuit including the secondary deslime cyclone converts to scavenger flotation duty to increase scavenger capacity. Each scavenger flotation circuit is preceded by a scavenger cyclone and two-stage conditioning. This new scavenger unit configures with the converted scavenger circuit in series with the existing scavenger circuit. It is possible to bypass the first scavenger circuit or run the scavenger circuits in parallel. Scavenger cyclone overflows and scavenger cell tails go to the flotation thickener. Scavenger concentrate returns to cleaner flotation.
The remaining steps for cleaner flotation, dewatering, and filtration remain unchanged from Stage 1. Equipment added in Stage 1 is sized for Stage 2 capacity. The storage area for final 5.4 percent Li₂O spodumene concentrate is unchanged from Stage 1. The process thickener circuit and flotation thickener circuit are sized for Stage 2 capacity and unchanged from Stage 1.
Stage 3 Description
In Stage 3, the existing crusher is repurposed as a dedicated ore sorting facility once the new crusher is operational. This ore sorting unit increases operational flexibility and simplifies the design while reducing capital cost for the new crusher facility. The existing secondary ore sorters are replaced with XRT ore sorters, which use particle density rather than surface properties. The primary ore sorter is not modified and is maintained for processing coarse ore. Sorted ore conveys to a new sorted ore silo or transports to the ROM. Sorted ore then feeds to the Stage 3 crusher ahead of the crusher screen.
Fresh ore from the ROM discharges to the new Stage 3 crusher through a 90 mm aperture vibrating grizzly, with oversize feeding a jaw crusher. Primary crusher product conveys to a double deck banana screen. The top deck oversize conveys to the secondary cone crusher. Bottom deck oversize material conveys to the tertiary cone crusher. Crushed product conveys back to the double deck screen for resizing. Crushed product underflowing the double deck screen has a nominal size of less than 10.2 mm F80 and conveys to a new fine ore stockpile. Fine ore reclaims from the ore stockpile and conveys to the plant feed conveyors.
The processing plant is unchanged from Stage 2 because the modifications required to reach 6,500 tpd capacity are completed in Stage 2.
Additional Interesting Data and Summary
The NAL expansion project is scheduled to process an annual average rate of 6,500 tpd of blended ore. Based on a plant feed Li₂O grade of 1.17 percent, the spodumene concentrate average annual production rate post-expansion is estimated at 373,000 tpa. The financial model considers this 1.17 percent feed grade, which differs from the process design criteria grades.
The existing crusher, ore sorting, new crusher and ore storage areas are designed for 65 percent availability. The processing plant, including milling, classification, desliming, magnetic separation, flotation and dewatering, is designed for 90 percent availability. The processing plant operates 24 hours per day, 7 days per week.
Metallurgical recovery improves at the onset of stage implementation and achieves an estimated 71.2 percent average over the life of mine. This recovery is supported by previous testwork. The recovery benefits from improved flotation feed sizing from increased classification capacity and mill power, improved magnetic separation circuit performance, improved flotation conditioning, improved rougher flotation control and flexibility, and improved cleaner tails handling. Recovery increases gradually through the staged approach with full benefits achieved by Stage 2.
Several work programs are underway or recommended. Plant trials on operating the existing WHIMS in parallel will help validate recovery increases assumed in the design. Flotation conditioning tests and lip surveys will increase understanding of potential improvements and identify circuit limitations and bottlenecks. Repeat surveys and simulations will assess new flotation feed particle size distribution and expected slimes generation. Additional optimization testwork on the WHIMS is recommended to understand limitations and set targets for plant operations.
Key Processes
- Primary, secondary, and tertiary crushing with ore sorting on run-of-mine material
- Grinding through rod mill and ball mill circuits with stacksizer classification
- Primary desliming cyclones targeting 10 µm cut point
- Magnetic separation using LIMS and WHIMS in multiple stages
- Two-stage conditioning for rougher and scavenger flotation circuits
- Rougher and scavenger flotation with individual cell level control
- Cleaner flotation with classifier cyclone for tailings handling
- Concentrate dewatering using cyclones and vacuum belt filters to 6% moisture
- Separate process water and flotation water circuits with dedicated thickeners
- Combined tailings management through agitated tank and dual pipeline system to TSF
Source: NAL Expansion FS Mineral Reserves Pre-Feasibility Study, August 14, 2026. Project website: North American Lithium
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.
Definitive Feasibility Study for the North American Lithium Project
This report details the processing design for the North American Lithium Project, based on the existing plant, historical operations, and current testwork.
Report context
This April 2023 report defines the recovery methods for the North American Lithium Project, which is based on the existing plant that was placed on care and maintenance in early 2019 and restarted concentrator operations in Q1 2023. The design incorporates historical operational data, metallurgical testwork, and equipment information from suppliers.
Processing route
Crushing and sorting
The primary crushing system includes an apron feeder sized at 6,100 mm × 1,219 mm for a daily throughput of 4,588 tpd, feeding a jaw crusher equipped with a 149 kW motor. The crusher is designed for a feed size of 309 mm and a product P80 of 94 mm, with an expected utilization of 65%.
A two-deck vibrating screen receives the jaw crusher product with a nominal feed size F80 of 94 mm. The top deck opening is 75 mm and the bottom deck opening is 20 mm. Top deck oversize reports to the primary ore sorter while bottom deck oversize reports to two secondary ore sorters. Screen undersize with P80 of 13 mm is directed to the tertiary crusher.
The primary and secondary ore sorters receive feed with a Li2O grade of 1.04%, with waste rejection estimated at 50% and feed upgraded to approximately 1.10% Li2O. The reject grade is estimated at 0.43% Li2O. The crushing circuit lithium recovery, including sorting, is 95.6%.
Grinding
The grinding circuit consists of an open-circuit rod mill followed by a ball mill in closed circuit with stack sizer screens. The rod mill has an installed power of 970 kW and reduces feed from a P80 of 13,000 µm to 1,050 µm at a nominal feed rate of 4,200 tpd. Six stack sizer screens divide the stream into oversize with P80 of 970 µm reporting to the ball mill, and undersize with P80 of 200 µm reporting to desliming. The ball mill reduces screen oversize and returns product to the screens for classification.
Desliming, magnetic separation, and flotation
The grinding circuit undersize reports to a desliming stage consisting of 17 operating cyclones plus two on stand-by, with an overflow cut size (D50) of 10 µm. Cyclone underflow passes through six attrition scrubbers, each with a volume of 13 m³ and retention time of approximately 16 minutes at a nominal flowrate of 206 m³/h.
The attrition scrubber discharge is processed in a low-intensity magnetic separator (LIMS) to remove ball mill chips. Slurry is diluted to approximately 29% solids by weight. One double-drum counter-rotation wet LIMS, providing a magnetic field strength of 950 gauss, handles this duty. The non-magnetic stream reports to two 13,000 gauss wet high-intensity magnetic separators (WHIMS) in series, with magnetic waste sent directly to the tailings thickener. The lithium recovery from desliming and WHIMS is 88.5%.
The deslimed stream is conditioned in a high-density conditioning tank with reagents at a retention time of 16.4 minutes and nominal slurry flowrate of 176 m³/h. Rougher flotation consists of three 30 m³ tank cells, followed by scavenger flotation in three additional 30 m³ tanks. The cleaning circuit comprises three stages: 18 conventional cells of 8.5 m³ each in the first stage, 13 conventional cells of 5.1 m³ each in the second stage, and 19 conventional cells of 2.8 m³ each in the third stage. First cleaner tailings report to the tailings cyclone; second and third cleaner tailings are recirculated internally.
Third cleaner concentrate reports to a concentrate storage tank with agitator, then to a belt filter producing concentrate at approximately 8% moisture by weight.
Tailings management
Tailings from the concentrator are collected in a final tailings tank. Scavenger and first cleaner tailings are pumped to a dewatering cyclone, with underflow at 48.9% solids by weight and a flow rate of 167 m³/h reporting directly to the final tailings tank. Cyclone overflow combines with first desliming cyclone residue, LIMS rejects, and WHIMS rejects and is pumped to an 18.3 m diameter steel-constructed thickener. Thickener underflow at 50% solids by weight and 34.8 tph solids is pumped to the final tailings tank at 47.7 m³/h.
A future tailings filter plant is scheduled for start-up in 2025, with two recessed plate filter presses (one operating, one on standby) designed to bring filter cake moisture below 15%. Filtrate and wash water are collected and pumped to a clarifier, with overflow partially treated through a multi-media filter for reuse as filter wash water and gland seal water.
Reagents and consumables
Primary reagents include collector (Custofloat 7080) at 1,118 tpy for rougher and scavenger flotation, dispersant (F220) at 354 tpy for attrition scrubbing and cleaners, soda ash at 181 tpy for pH control in the high-density conditioning tank, and flocculant (Flomin 920) at 61 tpy for thickening. Grinding media consumption is 949 tpy of 75 mm rods and 849 tpy of 50 mm balls.
Electrical distribution
The plant receives 4.16 kV power through one 5/6.7 MVA transformer/switchgear unit. Grinding mill motors are fed at 4.16 kV. Most 600 V power is generated through double-ended switchgear arrangements using 3/4 MVA transformers. The future tailings filtration plant will be fed through a 13.8 kV overhead power line with step-down transformers and switchgear.
Key reported parameters
| Criterion | Unit | Value |
|---|---|---|
| Crushing Plant Availability | % | 65 |
| Concentrator Availability | % | 93 |
| Total ROM Mine Feed | tpy | 1,557,000 |
| Concentrator Ore Feed | tph | 175 |
| Concentrator Ore Feed Per Year | tpy | 1,425,690 |
| Rod Mill Feed Grade | % Li2O | 1.10 |
| Concentrate Production | tph | 22.65 |
| Concentrate Production | tpy | 184,511 |
| Concentrate Grade (design) | % Li2O | 5.82 |
| Concentrate Grade (first four years) | % Li2O | 5.40 |
| Concentrate Iron Content (target) | % Fe | < 1.00 |
| Concentrate Humidity | % H2O | 8.0 |
| Concentrator Lithium Recovery | % | 66.3 |
| Crushing and Sorting Lithium Recovery | % | 96.5 |
| Desliming and WHIMS Lithium Recovery | % | 88.5 |
| Flotation Lithium Recovery | % | 78.4 |
| Concentrator Personnel | employees | 86 |
| Concentrator Salaried Staff | employees | 28 |
| Concentrator Hourly Workers | employees | 58 |
| Natural Gas Assured Supply | sm³/h | 3,400 |
| Natural Gas Consumption (crusher building heating) | sm³/month | 52,470 |
Technical qualifications
The report notes that other process modifications are still being developed, including the addition of a crushed ore storage dome to increase ore retention capacity and a tailings filter plant scheduled for start-up in 2025. Peak winter natural gas loads are expected to exceed the assured supply of 3,400 sm³/h; Énergir is investigating network expansion, and alternatives including LNG make-up or partial propane supply may be required if expansion does not materialize. The report relies on reagent consumption rates based on flotation testwork. The concentrator currently has permits for 3,800 tpd throughput, with procedures underway to increase authorization to a maximum of 4,500 tpd; the current mass balance is based on nominal rod mill feed of 175 tph or 4,200 tpd.
Source: Sayona Mining Limited, NI 43-101 Technical Report, Definitive Feasibility Study for the North American Lithium Project, April 2023, Sections 17.1, 17.2, 17.3.3, and 17.3.7.
Preliminary Economic Assessment for the North American Lithium Expansion Project
This Preliminary Economic Assessment outlines the proposed expansion of the North American Lithium operation in Québec, Canada, from a current design capacity of 4,200 tpd to a new design rate of 6,500 tpd of concentrator feed.
Report context
This Preliminary Economic Assessment (PEA) for the North American Lithium Expansion Project, located in Québec, Canada, was prepared to evaluate the proposed expansion of the existing lithium processing facility. The expansion design is based on the existing plant configuration, historical operational data, metallurgical testwork as described in Chapter 13 of the report, and equipment information from suppliers. The study establishes the design basis for the plant, capital costs, and operating costs developed in this PEA. The report is dated as part of the technical documentation for the project, with the full document referencing the project location as Québec, Canada.
Processing route
Existing Plant Configuration
The North American Lithium operation is currently authorized at 4,500 tpd for the concentrator, with a plant design at 4,200 tpd and an authorized mining mineral feed rate of 4,700 tpd to produce spodumene concentrate. The existing operation consists of three distinct processing areas: crushing and ore sorting on the ROM ore to produce an upgraded plant feed for downstream processing; a spodumene concentrator producing a saleable spodumene concentrate using grinding, desliming, magnetic separation and flotation; and dewatering of the final spodumene concentrate and the concentrator tailing material.
Proposed Expansion Design
The NAL process plant expansion is designed to increase the overall plant capacity to a design rate of 6,500 tpd. This will be achieved through several key modifications:
1. Replacement of the crushing and ore sorting area with a new circuit capable of processing 6,800 tpd of ROM ore. Crushed ore is conveyed from the crushing and ore sorting area to a covered crushed ore stockpile with 15,000 tonnes live storage. The stockpile is equipped with 2 reclaim tunnels, each with 2 feeders and conveyors, providing feed to Concentrator 1 (existing) and Concentrator 2 (new).
2. The addition of a second concentrator (Concentrator 2) to be operated in parallel to the existing concentrator, enabling a combined concentrator process rate of 6,500 tpd of feed using grinding, desliming, magnetic separation and spodumene flotation.
3. Additional concentrate filters, and replacement of the existing tails dewatering area with a new tailings thickener receiving tail streams from both the existing Concentrator 1 and new Concentrator 2.
4. Redundancy in the existing WHIMS circuit is fulfilled by adding a third WHIMS.
5. A concentrate storage facility integrated into the existing plant building combining flows of Concentrator 1 and new Concentrator 2, improving on current plant concentrate rehandling.
Primary Crushing, Secondary Crushing and Ore Sorting
A ROM blend feeds the coarse ore to the Primary Crusher at a top size of 900 mm, and the crushed ore at a nominal Closed Size Setting (CSS) of 130 mm is transferred to the Oversize Grizzly via the Primary Conveyor which screens the ore at 90 mm. The +90 mm oversize from the Grizzly is fed to the Secondary Crusher and the resultant re-crushed ore at a nominal CSS of 90 mm is discharged onto the Primary Conveyor to join the material from the Primary Crusher and thus transferred to the Oversize Grizzly for rescreening.
The under-size material from the grizzly is transferred to Ore Sorting. Crushed material from Primary and Secondary Crushing is fed to the Sorter Screen where it is separated by size into four products:
1. Material from the top deck (-90 mm +75 mm) is transferred to the Primary Sorter Screen and wet screened. Washed oversize material is fed to the Primary Sorter, while wet screen undersize nominally -4 mm in size is transferred as a slurry to the existing Concentrator 1 rod mill.
2. Material from the second deck (-75 mm + 50 mm) is transferred to the Secondary Ore Sorter.
3. Material from the bottom deck (-50 mm + 25 mm) is transferred to the Tertiary Ore Sorter.
4. The screen undersize (-25 mm) reports to the Fine Ore Conveyor for transfer to the Covered Stockpile.
5. Rejects from all sorters are conveyed to the rejects stockpile to be loaded by front end loader onto trucks for disposal with the mine waste.
Tertiary Crushing and Fine Ore Storage
The sorter products are fed to the tertiary crushing circuit which consists of the Tertiary Crusher (nominal CSS of 18 mm) in closed circuit with the Tertiary Crusher Screen (cut size = 20 mm). The sorter stream is introduced to the circuit at the feed to the Tertiary Crusher Screen. Screen oversize is transferred to the Tertiary Crusher and the crushed material from the Tertiary Crusher returned to the screen.
The screen undersize at a nominal P80 of 8 mm reports to the Fine Ore Conveyor for transfer to the Covered Stockpile. The Covered Stockpile is a new weatherproof storage shed which stores the fine ore. Reclaim of the stockpile fine ore is by means of two sets of parallel reclaimers (4 in total), located in the reclaim tunnels under the Covered Stockpile, one set feeding the Existing Concentrator (Concentrator 1) and the second the Expansion Concentrator (Concentrator 2). Full plant feed can be supplied by a single feeder for each circuit, while the second feeder provides redundancy, reduces size segregation in the stockpile and maximises stockpile storage. This undercover storage eliminates environmental effects on the ore fed to the plant to provide a consistent feed moisture and all-weather availability.
Existing Concentrator (Concentrator 1)
Grinding and Desliming
The grinding circuit consists of primary open circuit rod mill followed by a ball mill working in a closed circuit with 6 x Stack Sizer Screens. The rod mill is fed at an average rate of 4,200 dtpd by the dedicated reclaimers on the Covered Stockpile and also receives the screen undersize slurry from the Primary Sorter Screen.
The Rod Mill product is pumped to the Ball Mill and the Ball Mill product is pumped to the Stack Sizer Screens. The oversize with a nominal P80 of 970 microns is returned to the ball mill. The undersize at a nominal P80 of 225 microns is deslimed by 17 x Primary Deslime Cyclones to remove slime material (nominal overflow cut size D50 = 10 µm). The slime material reports to the Tailings Thickener.
Magnetic Separation
The deslimed underflow from the above is diluted with process water and then pumped to a low-intensity magnetic separator (LIMS) followed by 2 x wet high-intensity magnetic separator (WHIMS) in series with a new parallel first stage standby WHIMS magnetic separator (2 Duty/1 Standby (new)). The magnetics extracted by both stages are combined and pumped to the Tailings Thickener.
The non-magnetic slurry from the above then reports to second stage deslime cyclones that returns the slime to the LIMS feed box. Second deslime stage cyclone underflow then undergoes high-intensity conditioning at 55% w/w solids with a fatty acid collector in the Rougher Conditioning Tanks, 2 x tanks in series. The conditioned slurry is fed to the feed box of the rougher flotation circuit via gravity.
Spodumene Flotation
The non-magnetic slurry from the above undergoes high-intensity conditioning with a fatty acid collector (FA-2) at 55% solids in the Rougher Conditioning Tanks, 2 x 26 m³ tanks in series. The conditioned slurry is diluted to 40% solids and overflows to the Rougher circuit, a bank of 3 x 30 m³ rougher flotation cells. The rougher tailing from the final cell is pumped to the Scavenger Deslime Cyclone. The cyclone overflow reports to the secondary deslime cyclone feed pumpbox and the underflow reports to the Scavenger Conditioning Tanks (2 tanks in series) which feed the Scavenger circuit, a bank of 3 x 30 m³ scavenger flotation cells. The Scavenger circuit provides additional flotation time to recover any remaining spodumene and the scavenger tailings are pumped to the Tailing Thickener for dewatering.
Rougher Concentrate and Scavenger Concentrates are combined and sent to Cleaner 1 Circuit, which also receives the Cleaner 2 tailings. The combined feed is processed through a bank of 18 x 8.5 m³ cleaner cells in two lines. Cleaner 1 tailing reports to the Tailings Thickener and Cleaner 1 concentrate is pumped to the Cleaner 2 Circuit.
Cleaner 2 circuit receives Cleaner 1 concentrate and Cleaner 3 tailings and processes it through a bank of 13 x 5.1 m³ cleaner cells in a single row. Cleaner 2 concentrate is recirculated back to the feed to Cleaner 1 Circuit and Cleaner 2 concentrate is sent to Cleaner 3 for final cleaning.
Cleaner 3 circuit receives Cleaner 2 concentrate and undertakes the final polishing of the spodumene concentrate to produce a saleable product using 19 x 2.8 m³ cleaner cells in a single row. Cleaner 3 tailings is recirculated back to the feed to Cleaner 2 circuit. Cleaner 3 concentrate is sent to the Concentrate Tank to commence dewatering.
Expansion Concentrator (Concentrator 2)
Grinding and Desliming
The circuit is fed via conveyor from the dedicated reclaim feeders drawing material from underneath the Covered Crushed Ore Stockpile at a design rate of 2,300 tpd. The grinding circuit consists of a single stage ball mill working in a closed circuit with 4 x Mill Cyclones targeting a grind size of P80 of 200 microns. Mill Cyclone underflow returns to the ball mill. Mill Cyclone overflow is deslimed by 12 x Primary Deslime Cyclones to remove slime material. The slime material reports to the Tailings Thickener.
Magnetic Separation
The deslimed Primary Deslime Cyclone Underflow from the above is diluted with process water and pumped to a low-intensity magnetic separator (LIMS) followed by 2 x wet high-intensity magnetic separator (WHIMS) in parallel (1 Duty/1 Standby). The magnetics extracted by both stages are combined and pumped to the Tailings Thickener.
Key reported parameters
| Criterion | Unit | Base | Expansion |
|---|---|---|---|
| Crushing Plant Availability | % | 65 | 65 |
| Ore Sorting Plant Availability | % | 65 | 65 |
| Concentrator Availability | % | 89 | 92 |
| Total ROM Crusher Feed | tpd | 4,385 | 6,800 |
| Concentrator 1 Capacity (Existing) | tpd | 4,200 | 4,200 |
| Concentrator 2 Capacity (New) | tpd | – | 2,300 |
| Total Concentrator Capacity | tpd | 4,200 | 6,500 |
| Total Concentrator Capacity (nominal) | Mt/y | 1.4 | 2.2 |
| Concentrator Feed Grade | % Li2O | 1.11 | 1.11 |
| Target Spodumene Concentrate Grade | % Li2O | 5.4 | 5.4 |
| Overall Lithium Recovery | % Li2O | 69.2 | 71.2 |
Project website: https://www.elevra.com/projects/north-american-lithium/
*Note: all parameters are design rating unless noted otherwise.*
Technical qualifications
The upgraded design will be based on the existing facility, and as such the lithium recovery anticipated following this expansion is 71.2% (at SC5.4 grade) and is based on current plant performance and improvements of ore sorting and WHIMS. Future testwork and increased lithium recovery initiatives are planned for the next stage of the project. The recovery methods for the Project were established based on the existing plant, historical operational data, metallurgical testwork as described in Chapter 13 of the report, and equipment information from suppliers. Expansion process design is based on the operational and metallurgical reviews of the past process plant operation and testwork data.
Source: Preliminary Economic Assessment for the North American Lithium Expansion Project, Québec, Canada, Section 17: Recovery Methods, Pages 185-189.
