Summary:
The property is underlain by the Auclair Formation, consisting mainly of paragneisses, of probable sedimentary origin, which surround the pegmatite dikes to the northwest and southeast. Volcanic rocks of the Komo Formation occur to the north and east of the pegmatite dikes. The greenstone rocks are surrounded by Mesozonal to Catazonal migmatite and gneiss (Franconi, 1978; Moukhsil et al., 2007).
The outcropping pegmatites at the Project are surrounded by a thick sequence of intensely folded paragneiss with minor concordant felsic porphyry sills. The paragneiss can be subdivided into two distinct groups observed in outcrop:
• Strongly bedded paragneiss with associated garnets, staurolite, andalusite, and occasional cordierite observed in drill core.
• Massive, quartz-dominant paragneiss with no bedding textures.
In the eastern portion of the deposit, a feldspar porphyry sill sub crops measuring 5 m to 10 m wide and oriented towards 100° azimuth. It is difficult to ascertain the dip, but this unit has been intersected in drilling and can be traced at depth with a dip of 60° to the south. The unit is strongly porphyritic, with feldspars measuring from 2 mm to 8 mm. The groundmass is predominantly biotite, with a weak foliation. Tourmaline is observed in close proximity to contacts with surrounding pegmatites.
To the north of the outcropping pegmatites, a lithology rich in biotite and amphibole has been identified both in outcrop and drill core. Biotite porphyroblasts are common and make up 20% to 30% of the total composition of the rock. The groundmass is a mix of plagioclase, biotite, and amphiboles. The quantity of amphibole is highly variable, with some areas described as gabbro due to the high concentration of coarse-grained amphiboles and biotite. This unit also exhibits a slightly elevated concentration of sulphides, which supports its mafic origin. This biotite-rich mafic intrusive is generally 2 m to 10 m thick, can be traced the length of the orebody, and dips 60° to 65° to the south.
As of June 2023, a total of 67 individual pegmatite dikes have been identified within the deposit (some grouped into swarms), with the potential of additional dikes to be delineated on the property along strike to the east of the Billy Diamond Highway and to the north-west. A Paleoproterozoic diabase dike cuts north-south through the deposit, possibly truncating the pegmatite dikes and altering the spodumene to sericite in proximity to the contacts of the diabase. The diabase may have been emplaced in proximity to a sinistral strike-slip fault that displaces the pegmatite at the centre of the deposit.
The geometry of the pegmatite dikes in the vicinity of outcrop is well understand and supported by drilling, which has confirmed continuity of both Li2O grades and thickness of mineralization at depth. The pegmatites have been grouped into clusters based on their spatial location and outcrop positions. In 2023, step-out scout drilling to the northwest of the outcropping 1700 pegmatite cluster continued to discover mineralized pegmatites under thin glacial overburden. Based on correlated intersections of pegmatites in wide-spaced drilling, the orientation of the pegmatites appears to rotate from 067° azimuth to 010° azimuth. This suggests that the deposit is either offset and rotated by a strike-slip fault to the north of the 1700 cluster, or there is a sigmoidal inflection of the structural “corridor” hosting the deposit. The deposit remains open to the north-west of pegmatite cluster 1900.
Spodumene is a relatively rare pyroxene that is composed of lithia (8.03% Li2O), aluminum oxide (27.40% Al2O3), and silica (64.58% SiO2). It is found in lithium-rich granitic pegmatites, commonly associated with quartz, k-feldspar, albite, muscovite with minor lepidolite, tourmaline, and beryl. Spodumene is the principal source of lithium found at the property.
The spodumene found on the property tends to have a pale-green colouration, with grain size varying from sub-millimetric to one metre lengths. Grain size tends to be very fine within a chilled margin on the dikes, usually 3 cm to 5 cm wide, and then increases towards the centre of the pegmatite dikes. Crystal orientation is generally perpendicular to the contacts on the dike within the first one to two metres of the dike contact, and then becomes random and chaotic towards the centre of the dike with a megacrystic texture.
Concentrations of spodumene within the pegmatite dikes range from 2% to 40%, with the majority of crystals between 1 cm and 8 cm in length. Towards the extremities of the dikes, and occasionally at depth, spodumene is sometimes replaced by either muscovite or sericite. Work is ongoing to better understand the alteration assemblages in 3D for the deposit.
Although spodumene is the dominant lithium-bearing mineral found within the pegmatites, some minor occurrences of lepidolite have been visually noted in drill core. These observations are rare, and accumulations of lepidolite have not been identified in laboratory testwork. Holmquistite has been observed within discrete veins in the encasing paragneiss in proximity (< one metre) to pegmatite contacts. The holmquistite presents as a purple, fibrous mineral within centimetric veins exclusively within the paragneiss. Other minerals identified in drill core include columbite, apatite, and beryl. Geochemical analyses for tantalum, cesium, and rare-earth elements have returned non-economic concentrations.