The Raleigh Lake Project is a lithium-rubidium mine located in the northwestern region of Ontario, Canada. International Lithium, a Canadian lithium exploration company, owns the project.
The company acquired the project in early 2016 and subsequently worked to determine pegmatite field’s lithium potential. It completed around 10,000m of drilling at the site in 2022.
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International Lithium published the maiden mineral resource estimate for the project in March 2023. It was followed by an initial Preliminary Economic Assessment (PEA) in December 2023.
The PEA outlines a lithium mining operation at Raleigh Lake to produce spodumene concentrate. It estimates pre-production capital cost of C$111.9m and sustaining capital of C$17.5m.
Total life of mine (LoM) operating costs were estimated to be C$381m ($272.3m) including concentrate transport.
The mine will produce 57 million tonnes (Mt) of material over LoM, comprising 4Mt of mill feed and 53Mt of waste.
Raleigh Lake will have an estimated life of nine years with an 11-year project duration.
Raleigh Lake Project Location
Raleigh Lake is located approximately 235km to the west of Thunder Bay city in the northwestern part of Ontario within the Kenora Mining district.
The project area comprises 2,305 Single Cell Mining Claims (SCMCs) covering 48,500 hectares (ha). The SCMCs are divided into two non-contiguous blocks- Raleigh Lake or White Otter and White Owl Lake.
The project site is accessible via paved Ontario Highway 17. The highway will lead to Doreen South Road leading to a 10km travel on a gravel forest road.
Raleigh Lake Geology and Mineralisation
The project is located in the Wabigoon sub-province of the Archean Superior Province of the Canadian Shield. The province hosts a greenstone belt comprising mafic metavolcanic rocks.
The geology of the project consists of Archean supracrustal rocks, mafic metavolcanic, and their metasedimentary counterparts.
Various granitic plutons and batholiths intrude these rocks.
The project is classified under rare metal pegmatites. The pegmatites are categorised as albite-spodumene sub-type.
Pegmatites plutonic rock comprises crystals with skeletal, graphic, or strongly directional growth-habits, or anisotropic layered mineral fabrics. They also contain giant or megacrystic crystals.
It is said to contain lithium-caesium-tantalum (LCT) pegmatites.
Lithium Mineral Resource Estimate
Total (open pit and underground) measured and indicated lithium mineral resources estimate is 2,293kt at a grading of 0.64% Li2O containing 6,824 tonnes of lithium.
Inferred lithium mineral resources of the mine is 3,902kt at a grading of 0.58% Li2O containing 10,499 tonnes of lithium.
Rubidium Mineral Resource Estimate
Total (open pit and underground) measured and indicated rubidium mineral resource estimate is 133kt at a grading of 0.67% Rb2O containing 822 tonnes of rubidium.
Inferred rubidium mineral resource estimate of Raleigh Lake is 123kt at a grading of 0.46% with 521 tonnes contained metal.
Mining and Recovery
The lithium rubidium project will use traditional open pit method which will include drilling, blasting, loading, and overhauling the material.
The mining equipment will include hydraulic excavators, front shovels, and/or wheel loaders with ancillary equipment such as vehicles, bulldozers, and graders.
The mine plan as per the PEA is based on a proposed production rate of 540,000 tonnes per year (tpy).
According to the PEA, the open pit will be 800m in length and 450m in width at the surface. The entrance to the pit will be at 475m above sea level with the lowest point will be at a depth of 330m above sea level.
It will feature two entrance ramps to access northern and southern sections of the pit.
The project plans to recover spodumene to 6% Li2O concentrate grade and develop a flowsheet to extract rubidium from the microcline.
The process plant will crush 1,500 tonnes per day (tpd) and process 1,500tpd in a dense media separation (DMS) plant to produce a nominal 56,000tpy of 6% Li2O at 81% recovery.
A viable flowsheet will involve crushing material to minus 12.7mm and screen at 1mm, followed by screening again at 6.3mm to make two streams- a coarse fraction (-12.7 mm / +6.3 mm) for the primary coarse DMS; and a fines fraction (-6.3 mm / +1.0 mm) which reports to the primary fines DMS.
The coarse and fine DMS circuits will be equipped with primary DMS cyclones (SG 2.65 to 2.7) and secondary DMS cyclones (SG 2.85) to separate spodumene from the gangue material to produce a 6.0% Li2O or a higher concentrate.
Project Infrastructure
The process plant buildings will include crusher building; multi-stage DMS plant building; solid-liquid separation building with tailings screw classifier area; assay laboratory; along with main control room and Motor Control Center (MCC) building among others.
Other infrastructure of the project will include waste rock and tailings storage facilities, a water treatment plant, a plant control system, port facilities, natural gas and diesel storage facilities.
The associated facilities will include communications, a camp, a concentrate haulage facility, heat recovery for High Voltage Alternating Current (HVAC), and fuel supply.
Raleigh Lake will be powered by the existing Hydro One 235kV main power transmission line near Highway 17.
The estimated power demand for the mining project is 4,660KVA.
Contractors Involved
A global sustainable consultancy firm Environmental Resource Management (ERM) prepared the PEA for the Raleigh Lake Project.
MRE Technical Report prepared by Nordmin Engineering, a Canadian engineering consultant.
