Summary:
The Nunavik Nickel inc. Project (NNiP) consists of a series of mineral deposits (Expo, Mesamax, Allammaq, Méquillon, Ivakkak and Puimajuq) which extend over 60 km.
All the magmatic Ni-Cu deposits at the Nunavik Nickel Project have essentially the same mineralogy. Petrographic work (Walker 2004a, 2004b) identified pyrrhotite (Fe1-XS) as the main sulphide mineral, followed by pentlandite ([Fe,Ni]S) and chalcopyrite (CuFeS2). Pentlandite occurs generally as a separate mineral and only rarely as exsolution lamellae in pyrrhotite. Pentlandite appears to be the main cobalt carrier. Niccolite (NiAs) and violarite (Ni, Fe)3S4 occur only rarely or are entirely absent. Intergrowth of both pentlandite and chalcopyrite with silicate minerals, particularly with serpentine, can be intricate. Magnetite (Fe3O4) is a minor constituent of the rock, the result of the breakdown of the original olivine into serpentine plus magnetite.
All of the NNiP Phase 2a projects are located in the geological province of the Ungava pit. The various deposits affected by the request for modification of the initial impact study are located in ground where the lithology is different from one deposit to another. Therefore, the Ivakkak deposit is composed mainly of volcanic rocks (basalt and volcanoclastic), the Méquillon deposit of volcanic and magmatic rocks (basalt, volcanoclastic and gabbro), the Nanaujaq deposit of sedimentary rocks (sandstone, quartzite, conglomerate and limestone) and the Expo deposit of igneous rocks (peridotite).
Surface deposits are mainly characterized by till from the last glaciation. This deposit type is made from a mixture of rock debris of various sizes ranging from fine particles (clay) to coarse (metric blocks). In the study areas of the Méquillon, Nanaujaq and Expo deposits, the till layer is generally continuous and has an average thickness of less than 1 m, whereas it is greater than 1 m at the Ivakkak deposit site.
According to Golder's report (2018), the Ivakkak pit deposit is believed to consist of a narrow peridotite-pyroxenitegabbro dyke within a sequence of mafic volcanic rocks and sedimentary rocks. The dyke mineralization includes massive sulphides (over 90% sulphides) and net-textured (between 25% and 75% sulphides). The disseminated mineralization would present trace amounts, approximately 25% sulphides. Pyrrhotite, chalcopyrite and pentlandite are the primary sulphide minerals. The deposit area includes the following major lithologies: mafic volcanic rock, metasediment, ultramafic rock and gabbro.
The Nanaujaq deposit presents lithology and mineralogical assemblages similar to the other deposits. The different lithologies include veins, stringers, sediment, basalt and gabbro. The different lithologies demonstrate disseminated sulphides including nickel, copper and platinum group elements.
The Expo South deposit presents lithology and mineralogical assemblages similar to the other NNiP deposits.
The different lithologies of the Expo South deposit's mineralized zone include a gabbroic intrusion, a peridotite and a metasedimentary unit. This formation type is seen in several other Nunavik Nickel mine deposits. The different lithologies demonstrate disseminated sulphides including nickel, copper and platinum group elements.
The Méquillon deposit is composed of a mafic-ultramafic intrusion. Like the Méquillon deposit, the Méquillon UG1 extension includes the following mineralizations: disseminated sulphides, net-textured sulphides, massive sulphides and sulphide veins. Pyrrhotite is the predominant sulphide and is found along varying amounts of chalcopyrite and pentlandite.
Geochemical characterization of waste rock, ore, tailings and borrow pits materials has been conducted during several sampling campaigns since 2006. Samples of waste rock from all the pits and mined lithologies, ore samples, tailings samples and surface soil samples distributed throughout the project were analyzed. These sampling campaigns enabled geochemical characterization of materials through chemical analyzes, acid generation potential analysis, metal leach analysis and metallurgical evaluations. Conclusions of these studies have determined that the majority of the lithologies present in the Méquillon deposit are classified as acidogenic (metasedimentary, ultramafic and gabbro rock which form around 90% of the waste rock). Ultramafic rock (approximately 85% of waste rock) is also classified leachable under the “Directive 019”. About 10% of the waste rock (mafic volcanic rock) is non-leachable and classified as low risk.