Tuesday, November 21, 2023
Room 303AB - Société du Plan Nord
The market for critical and strategic minerals is evolving rapidly. Lithium, for example, has gone from being a niche product to what is virtually a basic raw material. With an increased demand, metal prices are rising, raising the prospect of exploiting new types of deposits at lower grades and higher tonnages. This session will present these future exploration targets, their geology and their challenges.
This session will be offered in French and in English.
The industrial revolutions have come in waves since the end of the 18th century. Each one mobilized a different energy regime, technologies, social organizations and metals. To meet growing demand, new types of deposits were brought into production, characterized by different tonnage-grade pairs. As tonnages rise, grades fall, with breaks in gradient between each type of deposit (Lasky's law). We thus move from high-grade deposits during the initial innovations to disseminated deposits with lower grades: copper moves from clusters to porphyries, aluminum from karst to sedimentary bauxites and uranium from pitchblende veins to sandstones. This migration varies according to metallogenic, economic and geopolitical parameters. The technological metals of the sixth wave are experiencing or will experience this migration, in the case of rare earths, cobalt and lithium.
Nickel and cobalt are critical strategic elements that, together with several other elements on the Canadian list of Critical and Strategic “Minerals” (e.g., Cr, Cu, PGE, Mg, Sc, Te, Ti, V), are extracted from mafic to ultramafic ore systems. Canada is a major world producer of Ni and Co, with most of the past and present production coming from high-grade, sulfide-rich nickel deposits such as those in the Thompson and Lynn Lake districts of Manitoba, Sudbury in Ontario, Cape Smith in Quebec, and Voisey's Bay in Labrador. Nevertheless, low-grade, sulfide-poor deposits account for a growing share of Canada's overall nickel resources. The Dumont deposit in Quebec, the Crawford deposit in Ontario, and the Baptiste deposit in British Columbia are examples of this type of mineralization. There are several challenges associated with such low-grade deposits, the most important of which is recognizing the minerals that act as principal hosts of nickel. These may be sulfides (e.g., pentlandite, heazlewoodite) or nickel alloys (e.g., awaruite), which are metallurgically recoverable, and/or in the silicate matrix (e.g., olivine), which is metallurgically unrecoverable (or very difficult to recover).
The tenor of the mineralization (metal in 100% sulfides ± alloys) is determined by the composition of the magma (higher in high-temperature komatiitic systems, lower in low-temperature basaltic systems), the presence or absence of primary sulfides, and the degree of alteration (e.g., serpentinization) of the olivine-rich protolith, allowing redistribution of some of the nickel associated with silicates to form secondary nickel-rich sulfides and/or nickel alloys).
Despite the many challenges associated with exploration and mining of disseminated low-grade Ni-Co deposits, deposits of this type have the potential to change the outlook for nickel in Canada, both in terms of future production and in terms of the exploration strategies for discovery of new resources to support the transition to a greener economy.
2:10 p.m.
Over the past decade, lithium has become a metal of crucial importance for certain industrial sectors worldwide, due to its widespread use in electromobility and the development of technologies essential to the energy transition. This trend, amplified by the disruption and uncertainty caused by recent global crises, has led to a significant and steady increase in global demand for lithium. This increase is accompanied by a collective awareness of the vulnerabilities of industrial supply chains for strategic and critical mineral resources.
From a geological point of view, lithium is not rare on the planet, but its distribution, degree of enrichment (grade/tonnage) and availability raise major political concerns. Various deposit typologies, such as salars, pegmatites, granitic domes and geothermal brines, contribute to the complexity of exploration. In addition, the diversity of lithiniferous minerals represents a significant challenge for optimal extraction from a technical and environmental point of view.
In Europe, numerous inventories and systematic metallogenic studies of lithium deposits have been carried out on hard rock and geothermal brine deposits, in order to secure supplies for the lithium industry. This approach has also paved the way for mining projects such as EMILI on the Beauvoir granite dome in the Massif Central, and active exploration of geothermal brines in the Rhine Graben (shared by France and Germany).
This conference will set out the challenges facing the lithium market today and in the future. It will present the various opportunities and challenges facing Europe and France in addressing lithium supply issues.
Lithium remains a critical link in the global energy and electric mobility supply chain. Understanding the geological, geopolitical, societal and environmental complexities is essential to ensure a sustainable and responsible energy future. It is also essential for managing the ethical and sovereignty issues associated with the relocation of production within Europe.
2:45 p.m.
3:10 p.m.
Troilus Gold
Authors: Pierre-Arthur Groulier, Nicolas Guest, Kyle Frank, Remy Klick and Tyler Beattie (Troilus Gold)
The Troilus Archean Au-Cu deposit is located in the eastern part of the Frotet-Evans greenstone belt (Eeyou Istchee-James Bay region, Quebec). It was discovered during prospecting in 1987, and over 2 million ounces of gold and 70,000 tonnes of copper were produced between 1996 and 2010. The deposit currently holds 6.2 Moz of indicated Au and 2.2 Moz of inferred Au, and a new resource estimate is planned for the near future. Due to its unusual characteristics (low-grade, high-tonnage Au-Cu deposit with propylitic, potassic and phyllic alteration), the classification of the Troilus deposit has been and remains controversial (porphyry vs. orogenic type). A lithogeochemical study shows the complexity of the deposit's geological sequence with a bimodal volcanic sequence containing tholeiitic to transitional mafic rocks with boninites as well as intermediate to felsic calc-alkaline volcanic rocks with an adakitic signature. The volcanic pile is intruded by a complex suite of syn-volcanic intrusions, including the dioritic to tonalitic hypabyssal Troilus intrusion, with syn-/tardi-tectonics. The stratigraphy of the syn-volcanic rocks and their geochemical signatures suggest a complex tectonic environment with similarities to a forearc environment. This syn-volcanic phase is associated with early magmato-hydrothermal and VMS/exhalative alteration and mineralization. The sequence was subsequently folded and metamorphosed into upper greenschist and amphibolite facies during the D1 ductile deformation phase. The rocks are marked by a strong S1 penetrative foliation parallel to the primary bedding, indicating strong transposition, and a medium to steeply NE-dipping L1 stretching lineation. NE-SW F1 faults at a small angle to S1 cut the entire zone, and are intersected by E-W F2 faults. The factors controlling mineralization are mainly lithological and structural in nature. 3D modeling of the Au-Cu and Mo analyses shows significant metal zonation, probably inherited from the syn-volcanic mineralization episode, but it is clear that the deposit is strongly controlled by structure, notably by the D1 NE-SW faults, and ore shoots controlled by the stretching lineation and the intersection of faults F1 and F2. This rich and complex history makes classification difficult, and many questions remain unanswered (metal contribution of the various events?).
