The Whabouchi Mine is operated through Nemaska Lithium Inc. (NLI). Arcadium Lithium, through its subsidiary Québec Lithium Partners Limited, holds a 50% stake in NLI.
The remaining 50% economic interest in NLI is owned indirectly by the government of the province of Quebec, Canada, through Investissement Québec (IQ).
On March 06, 2025, Rio Tinto completed its acquisition of Arcadium Lithium plc. Rio Tinto is now the ultimate parent company of Arcadium Lithium, which will become Rio Tinto Lithium.
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Summary:
The Whabouchi Property is located in the Lac des Montagnes volcano-sedimentary formation and sits between the Champion Lake granitoids and orthogneiss and the Opatica Northeast, which comprises orthogneiss and undifferentiated granitoids. From the northwest to the southeast, the Property is underlain by the Champion Lake granitoids, a grey oligoclase gneiss and then by the Lac des Montagnes formation.
The Lac des Montagnes belt is approximately 7 km wide in the area, oriented northeast, and is principally composed of metasediments (quartz-rich paragneiss, biotite-sillimanite-staurolite schist and garnet-bearing schist) and amphibolites (mafic and ultramafic metavolcanics). These rocks are strongly deformed and cut by late granitoids (leucogranites and biotite-bearing white pegmatites) (Valiquette, 1975).
At the property level, the geology consists of a volcano-sedimentary assemblage metamorphosed to the amphibolite level. The volcanic rocks mostly comprise basalt-andesite rocks and gabbro formation. The primary textures are not identifiable, and no geochemistry data enables to correctly identify the rock types. The sedimentary units range from meta-conglomerates with elongated clasts to fine grained sedimentary units.
The volcano-sedimentary sequence is intruded by different bodies of granites and pegmatites with varying composition and probably age (no age constraints are available on the local intrusive bodies). The granites vary in texture and composition, from white and pink granite fine-grained granites to grey hornblende-oligoclase granite with phenocryst of pink microcline.
The pegmatite bodies form a swarm of interconnecting dykes and plug shaped intrusions. The Whabouchi dyke swarm comprises the Main dyke and a series of subsidiary dykes, like the Doris zone. The dykes vary in orientation from N055° to N070° and are steeply dipping towards the southeast (Main zone) and northeast (Doris). In cross sections, some of the dykes have different dip orientation and potentially connect to other dykes at depth. The corridor occupied by this dyke swarms as been recognized on a strike length of 1,340 m with a width ranging from 60 m to 330 m.
Mineralization
The regional prospecting done in the region over the years highlighted a potential for precious and base metal deposits. Cu, Zn, and Au lithogeochemical anomalies are found in the region, which is consistent with the volcano-sedimentary setting of this region.
The mineralization of economic interest at the Whabouchi site is found in spodumene-bearing rare metal bearing pegmatite dyke complexes. Spodumene is a lithium-bearing mineral, which contains 8% Li2O when pure. Spodumene also contains minor amounts of niobium and tantalum. Assays for spodumene normally range between 7.6% and 8.0% Li2O depending on the degree of replacement by Na2O. Typically, the Whabouchi pegmatite sampled from drill core averages 1.42% Li2O with values up to 5.19% Li2O. Recent mineralogical assessment shows minor amount of other Li-bearing minerals, such as petalite, muscovite, ferrisicklerite, cookeite, and holmquistite.
Two distinct phases are observed in the Whabouchi pegmatites: a spodumene-bearing phase comprising most of the pegmatite material and a lesser, white to pink barren quartz-feldspar pegmatite. The lithium mineralization occurs mainly in medium to large spodumene crystals (up to 30 cm in size) but petalite also occurs, averaging approximately 2.3% in the deposit (petalite contains approximately 4.5% Li2O). Muscovite also contains minor lithium and averages less than 2% in the deposit. Petalite and muscovite are not recoverable by the mineral processing method discussed in the present Report.