A feasibility study describes the proposed design of a concentrator to produce a chemical grade lithium spodumene concentrate from the PAK and Spark ore deposits.
Report context
This feasibility study technical report is dated July 2025, with document number J7829-0000-PM-REP-013 – Rev. 0. The mineral processing operation will be located at the PAK mine site approximately 175 km north of Red Lake, Ontario. The ore mined from the Spark and PAK deposits will be processed in the concentrator according to the ore processing schedule to produce a chemical grade lithium spodumene concentrate.
Processing route
Crushing and preconcentration
The concentrator will have a three-stage crushing plant that will divert mill feed to the XRT ore sorting circuit in order to reject mafic iron species. The crushing circuit uses a 110 kW single toggle jaw crusher as the primary crusher, followed by a 185 kW cone crusher as the secondary crusher and a 260 kW cone crusher as the tertiary crusher. The secondary crusher operates in open circuit with a triple deck dry vibrating screen, and the tertiary crusher operates in closed circuit with a single deck dry vibrating screen. Crushing circuit feed top size is 600 mm and product size is 13 mm (P100) with a P80 of 9.5 mm for grinding feed.
The XRT ore sorting circuit uses two ore sorters: a coarse sorter treating the +25-55 mm size range and a middlings sorter treating the +13-25 mm size range. The sorter waste rejection rate is 15% of ore sorting feed. The combined sorter waste grades are reported as 0.62% Li₂O (nominal) and 10.9% Fe₂O₃.
Grinding and classification
The grinding circuit consists of rod and ball mills with fine screen classification. The rod mill is a 500 kW unit, 3.05 m diameter by 4.57 m EGL, with overflow discharge and VFD drive. The ball mill is a 750 kW unit, 3.2 m diameter by 5.18 m EGL, also with overflow discharge and VFD drive. Rod mill product size (T80) is 1,000 µm, and ball mill product size (P80) is 200 µm. The ball mill operates with a circulating load of 243% of new feed. Grinding classification uses 8-deck wet vibrating fine screens with 300 µm aperture.
Gravity and magnetic separation
The gravity circuit includes a continuous centrifugal gravity concentrator as a rougher, with a regrind circuit consisting of a 45 kW ball mill (1.2 m diameter by 2.4 m EGL) in closed circuit with a three-deck fine screen. The spiral circuit includes rougher, scavenger, cleaner, and re-cleaner spiral banks.
The magnetic separation circuit includes two low intensity magnetic separators (LIMS) operating at 950 Gauss in parallel, and one rougher and one scavenger wet high intensity magnetic separator (WHIMS) operating at 10,000 Gauss.
Desliming and flotation
Desliming is performed prior to gravity separation, mica flotation, and spodumene flotation using hydrocyclone clusters with a cut size of 15 µm. After desliming, dewatering screens remove excess water.
Mica flotation is conducted at pH 10.5. The mica rougher circuit consists of one bank of six tank cells, each 10 m³, with a concentrate mass pull of 7.3%. The mica cleaner circuit consists of one bank of three mechanical cells, each 2.3 m³, with a concentrate mass pull of 5.8%.
Spodumene flotation is conducted at pH 8.5. The spodumene rougher circuit consists of one bank of six tank cells, each 10 m³, with a concentrate mass pull of 26.2%. Two stages of cleaning follow: the first cleaner has one bank of five mechanical cells, each 2.3 m³, with a concentrate mass pull of 22.7%; the second cleaner has one bank of five mechanical cells, each 2.3 m³, with a concentrate mass pull ranging from 19.7% to 25.4%.
Concentrate and tailings handling
Concentrate thickening uses a high rate thickener, 12 m diameter. The concentrate filter is a vertical pressure filter (Larox type) with a filtration rate of 0.55 t/h/m² and filter cake solids of 93.0% w/w. Concentrate is stockpiled in a conical stockpile with 8,000 tonnes live capacity.
Final tailings thickening uses a high compression thickener, 16 m diameter. Final tailings are thickened and pumped to the Tailings Management Facility (TMF) for storage and water recovery. The design of the TMF was completed by SLR.
Water and power
Fresh water is taken from an external water source for process water circuit makeup, gland seal duties, fire protection, and potable water treatment. Reclaim water is sourced from final tailings thickener overflow, mine collection water from PAK and Spark water ponds, and water recovered from the tailings pond. Process water is also recovered as overflow from the concentrate thickener. Electrical power will be provided by the projected Watay Power Line via overland power line. Diesel generators will be used for emergency power generation, with expected emergency demand for the process plant of 1,079 kVA.
Key reported parameters
| Description | Unit | Nominal | Design |
|---|---|---|---|
| Processing Operations Setup | |||
| Crushing Runtime | % | 70.0 | 70.0 |
| XRT Ore Sorting Runtime | % | 70.0 | 70.0 |
| Concentrator Runtime | % | 90.0 | 90.0 |
| Filtration Runtime | % | 85.7 | 85.7 |
| Plant Throughput – LOM Average | |||
| Daily Ore Processing Rate | t/d dry | 2,849 | 3,277 |
| Head Grades (LOM Average) | |||
| Spark Lithium | % Li₂O | 1.44 | 1.60 |
| Spark Iron | % Fe₂O₃ | 1.66 | 2.28 |
| PAK Lithium | % Li₂O | 1.96 | 2.42 |
| PAK Iron | % Fe₂O₃ | 0.68 | 1.00 |
| Concentrate Quality – LOM | |||
| Li₂O Recovery – Spark and blends | % | 77.6 | 77.6 |
| Li₂O Recovery – PAK | % | 78.0 | 78.0 |
| Li₂O Grade | % Li₂O | 6.00 | 6.00 |
| Fe₂O₃ Grade | % Fe₂O₃ | 1.00 | 1.00 |
| Concentrate Mass Pull | % of ROM | 19.7 | 25.4 |
| Ore Comminution Properties – Spark | |||
| Bond Ball Mill Work Index (BWi) | kWh/t | 11.1 | 12.3 |
| Bond Rod Mill Work Index (RWi) | kWh/t | 11.4 | 12.3 |
| Crushing Work Index (CWi) | kWh/t | 9.2 | 9.2 |
| Abrasion Index (Ai) | g | 0.543 | 0.543 |
| Ore Comminution Properties – PAK | |||
| Bond Ball Mill Work Index (BWi) | kWh/t | 12.4 | 13.6 |
| Bond Rod Mill Work Index (RWi) | kWh/t | 12.7 | 13.8 |
| Crushing Work Index (CWi) | kWh/t | 10.9 | 10.9 |
| Abrasion Index (Ai) | g | 0.573 | 0.573 |
Project website: https://www.paklithiumproject.com/
Technical qualifications
The process plant design is derived from data and design criteria provided by Frontier, developed design data by DRA, vendor data, test work results summarized in Section 13 of the Report, and regulatory permitting requirements. The design of the concentrator is based upon the test work results of the 2021-2022 SGS test work program as well as historical test work program results from 2016-2021, as applicable. The rod and ball mill sizing is based on achieving the grind size required to obtain the required spodumene concentrate tonnage and quality as well as the outcomes of the metallurgical test work and mill simulations. The basis for the development of the concentrate recoveries and grades were the results of the bench scale at pilot plant testing completed by SGS in 2021-2022 under Frontier’s supervision. All throughput and mass balance calculations used as the basis of design were based on an average mill feed of 1.04 Mtpa to produce an LOM average 201 ktpa of 6.0% Li₂O chemical grade concentrate. For equipment influenced by volumetric flow, their sizing is based on the requirement for 115% of the instantaneous flow. For other equipment items, the peak production rates were used for sizing.
The concentrator starts processing Spark ore in August 2030 and by February 2031 throughput ramp up is completed. Spark ore is only being processed up until the end of 2046. PAK ore processing commences in Year 2047 in a blend with the Spark ore. 2060 is the last year of concentrator operation.
*Source: NI 43-101 Technical Report, Feasibility Study, PAK Lithium Project – Mine and Mill, July 2025, DRA Ref.: J7829-0000-PM-REP-013 – Rev. 0, Section 17.*
