A feasibility study for the Moblan Lithium Project outlines a proposed open pit mining operation and concentrator design based on metallurgical testwork and mineral reserve estimates in the Eeyou Istchee James Bay territory of Quebec, Canada.
Report context
InnovExplo Inc. was commissioned by Sayona Inc. to prepare a mineral reserves estimate for the Moblan Lithium Project using InnovExplo’s 2023 geological resource model and mineral resources estimate as its basis. The feasibility study report, prepared in accordance with National Instrument 43-101 Standards of Disclosure for Mineral Projects and its related Form 43-101F1, presents the results of the mineral reserves estimate and the supporting feasibility study. The effective date of the mineral reserves estimate is January 24, 2024.
Processing route
Sample representation and compositing
Metallurgical recovery assumptions are based on historical metallurgical tests and ongoing metallurgical testing conducted under the supervision of independent qualified persons and Sayona representatives. Composite samples were generated from drill holes in two phases. Phase 1 composites from the 2022 program and Phase 2 composites from 2022 and 2023 programs range in grade from 0.70 to 1.73% Li₂O and 0.74 to 1.41% Fe₂O₃. The majority of testing was on near-mine grade material for Li₂O but below-mine grade for Fe₂O₃. Near-surface material was used for bulk sampling and testing the ore sorting technology.
Comminution and ore sorting
Comminution test data from 2011 to 2023 were compiled. Ore sorting testwork was conducted using TOMRA and Steinert equipment in 2022. Coarse ore sorting results show iron rejection capabilities with associated lithium loss, and fine ore sorting results present lithium loss versus iron rejection curves.
Proposed concentrator flowsheet
The design of the spodumene concentrator process plant is based on commercially proven dense media separation and flotation circuit technology and includes the following:
- A three-stage conventional crushing and screening circuit
- Ore sorting circuit on primary crushed material (to control the high iron in the run-of-mine)
- Dense media separation screening and mica removal via up-flow classification
- Two-stage dense media separation circuit for coarse fraction with magnetic separation of concentrate
- Two-stage dense media separation circuit for fines fraction with magnetic separation of concentrate
- Grinding and flotation circuit for the middlings and ultrafines fraction
- Thickening, filtration and dry stacking of hypofine fractions with the waste rock
- Magnetic separation on the flotation feed in conjunction with the previously noted step in dense media separation
- Tailings from the dense media separation plant trucked for co‑disposal pile with the waste rock
The primary crushed product is diverted to the ore sorter circuit when required. The crushing circuit will produce a nominal 6.35 mm product screened into coarse (-6.3 +4.0 mm) and fine (-4.0 +1.0 mm) streams to be fed to the respective dense media separation circuits. The fines will be fed through a reflux classifier to remove mica before being fed to the fines dense media separation circuit.
Heavy liquid separation and dense media separation testwork
Heavy liquid separation test results from 2012 to 2018 and 2022 to 2023 were evaluated for SC6 versus crush size relationships and the impact of Fe₂O₃ on sinks Li₂O grade. Dense media separation testwork conducted in 2022 at SGS compared data with heavy liquid separation trends for lithia grade and recovery relationships. Magnetic separation testwork was performed on dense media separation concentrate in 2022.
Flotation and variability testwork
Mica and spodumene flotation testwork was conducted from 2011 to 2022. Bench-scale testing was performed on MG samples in 2022 for mica flotation data and mica flotation Fe:Li ratio, and for spodumene flotation Li upgrade. Infill samples in 2023 were tested for spodumene flotation Li₂O data. Variability composite results and locked cycle results for spodumene flotation composites were generated.
Thickening and filtration
Thickening and filtration test summaries were completed for the proposed dewatering circuits.
Recovery calculation and assumptions
A global recovery was calculated using bulk testwork and pilot data and then compared to the bench-scale test program results and trended across the feed grades straddling the proposed mine Li₂O grade. The recoveries over the life of mine range from 72.3 to 77.9% with varying Li₂O and Fe₂O₃ grades. The main metallurgical assumption is that production generates a 6% Li₂O concentrate with an average metallurgical recovery of 74.9% Li₂O. The concentrate grades and Li₂O recovery across the range of feed grades vary from 5.6 to 6.2% Li₂O and 72.3 to 77.9%, respectively. Note that pilot-scale testwork has been undertaken for dense media separation and flotation processes, though runs used a material that is above mine grade, with flotation results showing that there is potential for lower recoveries if flotation conditions vary from design or feeds do not show similar mineralogy to those tested.
Proposed plant design basis
The processing facility will be located near the proposed open pit operations. The spodumene concentrate will be produced via processing through dense media separation and flotation circuits. The plant is designed to produce a minimum 6.0% Li₂O spodumene concentrate from an ore grade of 1.36% Li₂O (diluted), with an average iron (Fe₂O₃) content of 1.47%. The concentrator is designed to nominally process 1,752,000 tpy.
Process design criteria
Key concentrator design criteria were established including process plant water balance and a simplified concentrator flowsheet. Major reagents used in the circuit were identified.
Key reported parameters
| Parameter | Value | Unit | Basis |
|---|---|---|---|
| Mine ore grade (diluted) | 1.36 | % Li₂O | Proposed design |
| Average LOM recovery | 74.7 | % | Testwork and calculation |
| Concentrate grade | 6.0 | % Li₂O | Design target |
| Average iron grade | 1.03 | % Fe | Proposed design (LOM average) |
| Average Fe₂O₃ grade | 1.47 | % Fe₂O₃ | Proposed design (LOM average) |
| Composite Li₂O range | 0.70 – 1.73 | % | Testwork composites |
| Composite Fe₂O₃ range | 0.74 – 1.41 | % | Testwork composites |
| Recovery range (LOM) | 72.3 – 77.9 | % | Based on feed grade variability |
| Concentrate grade range | 5.6 – 6.2 | % Li₂O | Based on feed grade variability |
| Crushing product size | 6.35 | mm | Design |
| DMS coarse fraction | -6.3 +4.0 | mm | Design |
| DMS fine fraction | -4.0 +1.0 | mm | Design |
| Maximum Fe exclusion | 2.80 | % Fe | Reserve exclusion threshold |
| Milling capacity | 4,800 | tpd | Proposed design |
| Operating days per year | 365 | days | Proposed design |
| LOM concentrate production | 5,848,179 | t @ 6% Li₂O | Proposed design |
Project website: https://norda.com/en/projets/moblan-project/
Technical qualifications
The following limitations and qualifications apply to the metallurgical and processing data in this report:
- The iron content can impact metallurgical recovery and spodumene concentrate quality. Ore shapes containing more than 2.80% Fe have been excluded from the Mineral Reserves Estimate.
- Some interpretation has been required to compare near-surface bulk sampling with below-surface composites.
- Pilot-scale testwork has been undertaken for dense media separation and flotation processes, though runs used a material that is above mine grade, with flotation results showing that there is potential for lower recoveries if flotation conditions vary from design or feeds do not show similar mineralogy to those tested.
- The current proposed flowsheet with 5% ROM dilution should produce a final concentrate with a lithia grade of 6.0% and Fe₂O₃ less than 1.4%.
- An analysis of the financial model on the main economic assumptions and operating costs indicates that the Project is profitable.
Source: NI 43-101 Feasibility Study Report for the Moblan Lithium Project, Eeyou Istchee James Bay Territory, Quebec, Canada, February 2024, sections 1.8, 13, 14.14, 15, 17.
