The Kangerluarsuk Zinc-Lead-Silver ± Copper-Germanium Project, Central West Greenland
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Located approximately 60 km northeast of the settlement of Uummannaq, 225 km north of the city of Ilulissat and 800 km north of the capital, Nuuk, the Kangerluarsuk project covers an area of 692 square km in Central West Greenland. The project flanks the Kangerluarsuk fjord and comprises of two 100% owned exclusive mineral exploration licences, namely MEL 2011/31 (107 square km) and MEL 2020/06 (586 square km).
Central West Greenland is one of the most economically vibrant areas of Greenland, serviced by excellent modern infrastructure. Bluejay’s activities at Kangerluarsuk and Disko-Nuussuaq are supported by its in-country logistical hub, consisting of an office, warehousing and storage facilities, based in Illulissat (the municipal seat and largest city of the Avannaata municipality). Bluejay has been operating in the region for many years and has excellent relations with a wide range of suppliers and contractors. We are a well-known and trusted customer, partner and employer in the region.
As part of the largest infrastructure investment in Greenland’s history, the international airport at Ilulissat is being upgraded with construction beginning on a new terminal building and 2,200 m runway capable of accepting much larger aircraft. Ilulissat also benefits from a deep-water container port. Closer to the project area, there is a permanently staffed domestic airport at Qaarsut and a heliport at Uummannaq.
Both licences are held by Disko Exploration Ltd., a 100% owned subsidiary of Bluejay Mining plc. Licence MEL 2011/31 was formally held by Avannaa Resources (hereafter “Avannaa”). Bluejay acquired this licence in January 2017 when it purchased Avannaa and its exploration assets in an all-share transaction with its parent company, Cairn Energy plc.
Owing to the potential the Company recognises in the Karrat Group metasedimentary basin for large scale base metal deposits, Bluejay further increased its landholdings at Kangerluarsuk five-fold. In January 2020, Bluejay was awarded exploration licence MEL 2020/06 by the Greenlandic Mineral Licence and Safety Authority (refer to Bluejay RNS dated 27th January 2020).
The Paleoproterozoic Karrat Group
The Paleoproterozoic (ca. 1.9 – 2.0 Ga) Karrat Group is an approximately 8.5 km thick metasedimentary succession that unconformably overlies reworked Archean (2.7 – 3 Ga) orthogneisses of the Rae Craton. It extends from ~71° to ~75°N and is composed of the Qaarsukassak, Mârmorilik, Kangilleq, and Nûkavsak formations. It is exposed over a N-S distance of ca. 550 km and covers an area of >10,000 square km. The Karrat Group correlates with the Penrhyn and Piling Group supracrustal rocks of the Foxe Belt in NE Canada.
The lower part of the Karrat Group is represented by the Qaarsukassak and Mârmorilik formations. Both formations are overlain by the Nûkavsak fm. which is intercalated with metavolcanic rocks of the Kangilleq fm.The Qaarsukassak fm. is a recently defined formation comprising of siliciclastic and carbonate rocks, and hosts the Zn-Pb-Ag mineralisation at Bluejay’s Kangerluarsuk project The Mârmorilik fm., is dominated by calcite and dolomite marble; fine-grained locally graphite-bearing schist; quartzite; and metamorphosed evaporites in the form of anhydrite, and hosts the Zn-Pb-Ag mineralisation at the Black Angel Mine. The approximately 5 km thick Nûkavsak fm., contains metagreywacke and metapelite, which are interpreted as turbidite flysch sequence. Locally contains pyrrhotite-chert-graphite horizons. Based on new geochronology data the former Qeqertarssuaq fm. (in earlier mapping by Henderson and Pulvertaft, 1987), has been removed from the Karrat Group and included in the Neoarchean gneiss complexes.
The lower units (Qaarsukassak and Mârmorilik fms.) of the Karrat Group formed in an intracratonic sag basin as the Rae Craton subsided. The basin progressively evolved through an intracratonic rift stage, with associated volcanism (Kangilleq fm., alkaline member) and syn-rift siliciclastic sedimentation (Nûkavsak fm.) between 1950 and 1900 Ma, to a later stage back-arc geodynamic setting (Kangilleq fm., transitional member). Between 1870 – 1850 Ma, the Karrat basin was intruded by calc-alkaline felsic intrusions of the Prøven Igneous Complex (‘PIC’).
The Karrat Group was affected by metamorphism during the collisional phase of the Rinkian Orogen (Cordilleran-type tectonics) between 1830 and 1800 Ma, reaching upper greenschist facies in the south (at Black Angel and Kangerluarsuk), to granulite facies in the north, where the metamorphism is associated with migmatization and emplacement of the S-type leucogranites. The Rinkian orogen is interpreted as part of the Trans-Hudson Orogeny (St-Onge et al., 2009) and represents a back-arc fold and thrust system, resulting from the eastward collision between the magmatic arc PIC and the Karrat basin. The inversion of the Karrat Basin involved a first stage of thin-skinned tectonics, with allochthonous metagreywackes emplaced during east-verging thrusting, followed by thick-skinned tectonics (inversion) with progressive involvement of the Archaean gneisses with basement nappes and metasediments transported toward the north-east.
The Qaarsukassak Formation in detail:
The Qaarsukassak fm. was originally interpreted to represent a structurally displaced basal component of the Mârmorilik fm. (that hosts Black Angel mine). It is now recognised as a separate formation based on recent studies by Guarnieri et al., 2016. The Mârmorilik and Qaarsukassak formations were both deposited directly on Archaean crystalline basement rocks and likely have similar depositional timing; however, they are separated by a basement topographic high (on Alfred Wegener Halvø) and are not observed in stratigraphic contact.
Qaarsukassak fm. (ca. 2.0 Ga) at the “Discovery Zone” ranges from 30 to 66 m thickness. The lower contact with the Archean Umanak gneiss (ca. 2.9 – 3.0 Ga) is a planar to undulating erosional surface that preserves a depositional contact. Laminated to massive quartzite fines upward into fine-grained metamorphosed sandstones and sandy mudstones, including calcite-cemented and graphitic quartzites (“Unit 1”). Asymmetrical ripple marks in the basal metasandstone suggest a fluvial to marginal marine setting. These siliciclastic rocks are overlain in sharp contact by light grey to white calcitic metacarbonate rocks with pods of massive tremolite and in some horizons, minor graphite (“Unit 2”). This is succeeded by another quartzite unit (“Unit 3”), followed by dark grey, laminated calcitic metacarbonate rocks with possible slump folds and minor tremolite veining (“Unit 4”). The overlying, rusty weathering metasedimentary rocks including graphitic, metamorphosed mudstones and siliciclastic rocks (“Unit 5”) that represent the ore zone (e.g., Guarnieri et al., 2016; Partin et al. 2021). Recent regional mapping by GEUS demonstrates the potential for Qaarsukassak fm. hosted Zn-Pb mineralisation throughout the Karrat Basin.
The upper contact with the Nûkavsak fm. is not well exposed. Suggested that it locally preserves a sedimentary contact (Partin et al., 2021), though in many places the contact is now a structural (thrust contact) and the Nûkavsak fm. considered to be allochthonous. Also of note is a thin re-sedimented calcitic marble horizon within the basal part of the Nûkavsak fm., which might be derived from contemporaneous erosion of the Qaarsukassak fm. (Guarnieri et al., 2016). Variable thickness of the formation along strike suggests that deposition of the Qaarsukassak fm. was infilling post-unconformity basement paleo-topography (Guarnieri et al., 2016). Later thickening through structural repetition caused by thrusting and tectonic imbrication is also recognised.
Located in a proven Zn-Pb-Ag mining district:
Bluejay’s Kangerluarsuk Zn-Pb-Ag project located only 12 km north of the former Black Angel mine, widely acknowledged as the most profitable mine in Greenland to date. At Black Angel, the Zn-Pb-Ag mineralisation is hosted within the Paleoproterozoic Mârmorilik fm. of the Karrat Group (calcitic and dolomitic marbles with a basal quartzitic unit and intercalations of anhydrite-bearing marbles and semipelitic schists, deposited in a carbonate shelf on the margins of an intracratonic sag basin) which were deposited ca. 1.9 Ga. The Mârmorilik fm. represents a shallow-water, stromatolite-bearing marine carbonate platform.
The mine was operated by Cominco (now Teck) between 1973–1986 and later Boliden from 1986–1990. The deposit comprised of eight different orebodies and two satellite orebodies (the Nunngarut orebodies) with pre-mining reserves totalling 13.6 million tonnes @12.3% Zn, 4.0% Pb and 29 g/t Ag. The mine produced 11.2 million tonnes @ 12.6 % Zn, 4.1 % Pb and 29 g/t Ag during the 17-year mine life (Thomassen, 2003). Approximately 2.4 million tonnes of ore are known to remain in unmined pillars and other areas that were considered inaccessible to mining. Continued exploration following mine closure has identified several new satellite orebodies within the Mârmorilik Fm. (e.g., Glacier, Glacier North and ARK). Within the Black Angel district there are numerous (>200) mineralised showings with mineralisation occurring in different stratigraphic positions.
The stratabound orebodies at Black Angel are hosted in anhydrite-bearing marble and consist of massive to semi-massive sphalerite-galena-pyrite, with minor to trace amounts of chalcopyrite, arsenopyrite, tetrahedrite, freibergite, tennantite, stannite, briartite, enargite, loellingite, polybasite, magnetite, rutile, and graphite. Despite a long exploration and mining history, the genetic model for the mineralisation remains debated (due to the effects of greenschist-facies metamorphism and intense multi-stage deformation that have affected and remobilised the ore). The deposit has been classified as an exhalative sediment-hosted massive sulphide (SEDEX) deposit (e.g., Leach et al., 2005); an epigenetic Mississippi Valley-type (MVT) deposit (e.g., Partin et al., 2021; Rosa et al., 2023); and a metamorphic Kipushi-style deposit (Horn et al., 2018). An MVT model is the most favoured model in the current scientific literature for Black Angel.
Recent mineralogical studies identified hitherto unrecognised germanium endowment within the Black Angel ore. Untested elsewhere in the Karrat Basin, although early mineralogical work on samples from Bluejay’s Kangerluarsuk project by Karlsruhe Institute of Technology, Germany, supports a potential for germanium associated with the Zn-Pb-Ag mineralisation.
Mineralisation at the Kangerluarsuk Project
The known mineralisation at Kangerluarsuk generally occurs within tens of metres of the unconformable erosional contact with the Archaean basement (Umanak gneiss). The metamorphosed/recrystallised Zn-Pb-Ag mineralisation at the Discovery Zone and Kangerluarssup Glacier Showings occurs intermittently at surface over a strike length of 9 km. It is stratabound and contains massive, medium- to coarse-grained pyrite, pyrrhotite, “blackjack” sphalerite, galena and sulfosalts hosted by ferruginous horizons within the dominantly siliciclastic, uppermost unit (“Unit 5”; cf. Guarnieri et al., 2016) of the Qaarsukassak fm. By contrast the very finely banded texture of the Zn-Pb-Ag-Cu mineralisation from the Kangerluarssup Glacier Showings (KGS; approx. 9 km south of the discovery zone) are almost certainly due to deformation rather than primary textures. The KGS mineralisation also contains chalcopyrite in its sulphide assemblage.
Bluejay considers the Discovery Zone and KGS showings to be the distal expressions of a large buried base metal deposit(s). An exhalative sediment-hosted massive sulphide (SEDEX) model has been suggested as the most likely deposit model for Kangerluarsuk (e.g., Partin et al., 2021), which has been structurally modified and metamorphosed. However, based on the correlation with the Mârmorilik fm. (including the presence of calcitic metacarbonates in the Qaarsukassak fm.) and several characteristics that are considered atypical for SEDEX deposits, an MVT model has also been proposed (e.g., Dr. Diogo Rosa, Pers. Comm.). Earlier operators, Rio Tinto Zinc and Avannaa Resources, highlighted geological similarities with some of the world’s more valuable base metal deposits including the Sullivan deposit (162mt @ 5.9% Zn and 6.1% Pb) in the Yukon and the Rammelsberg deposit (25mt @ 18.1% Zn, 8.6% Pb and 1.1% Cu) in Germany.
References and recommended reading:
The project benefits from a large knowledge base comprising of both commercial exploration, government-funded programmes and academic studies, since the 1960’s:
1962/63: The Geological Survey of Greenland (GGU) mapped the Karrat Group at the scale 1:100,000.
1970’s – 90’s: The former Black Angel mine was operated from 1973 to 1986 by Cominco (now Teck) and from 1986 to 1990 by Boliden. During this period, Cominco and Greenex A/S carried out regional exploration for Zn-Pb, Cu, Au and diamonds.
Cominco discovered abundant high-grade mineralisation in shelf carbonates and mapped out extensive sulphide-rich horizons, locally with base metal enrichment, within the Karrat metasediments, as well as the first findings of Zn-Pb ± Cu mineralised float at the head of the Kangerluarsuk Fjord (within Bluejay’s current licence areas).
1991/92: A Joint Venture between Rio Tinto Zinc (‘RTZ Mining and Exploration Ltd.’) and Platinova Resources discovered several zones of high-grade outcropping mineralisation at Kangerluarsuk up to 41% Zn, 9.3% Pb, 1.2% Cu and 596 g/t Ag and channel samples assaying 45.4% Zn and 41.1% Zn over 0.4 and 1 metres respectively, all within Bluejay’s current licence area.
1989/90, 92, 97: The GGU (Geological Survey of Greenland; later the Geological Survey of Denmark and Greenland, GEUS) carried out a regional geochemical reconnaissance throughout the Karrat Group, including stream sediment and heavy mineral concentrate (HMC) sampling. The resulting geochemical maps show an outstanding base metal anomaly (Zn associated with Ni, Cu As, Cd, Cs, Y and REE) at Kangerluarsuk over an area of >100 square km, indicating a polymetallic deposit potential.
The anomalies at Kangerluarsuk are more pronounced than those surrounding the Black Angel mine. Kangerluarsuk is acknowledged by GEUS as the strongest cluster of stream sediment zinc anomalies identified in the whole of Greenland. Significant nickel anomalies (the strongest in the whole of the Karrat Group) may relate to mafic-ultramafic metavolcanics of the Kangigdleq fm., which are present in the licence areas but the cause of the nickel anomalism has not yet been confirmed.
1994-95: Cominco carried out exploration for komatiite-hosed orthomagmatic Ni-Cu deposits within the Kangigdleq fm., of the Karrat Group based upon analogies with the comparable geological settings of both the Thompson and Cape Smith nickel belts in Canada.
1997: Platinova Resources commissioned a 435 line-km helicopter-borne DIGHEMV electromagnetic and magnetic survey over Bluejay’s current licence area.
2007-11: Avannaa Resources carried out exploration throughout the Karrat Group for Zn-Pb, Au and rare earth elements (REE). This resulted in the discovery of the Karrat Isfjord REE prospect, which was later drilled by Avannaa. Mineralisation at Karrat Isfjord is considered to result from the metasomatic alteration of amphibolite host rocks by a ferrocarbonatite-derived fluid, within a shear zone. Whole rock assays yielded up to 2.6 % TREO. Later Avannaa acquired the Kangerluarsuk project (see next section, “recent exploration”).
Prior to Bluejay acquisition of the Kangerluarsuk Project (MEL 2011/31) in 2017, the previous licence holder, Avannaa Resources had carried out an aggressive campaign at Kangerluarsuk from 2011 to 2013, including:
EIT RawMaterials UpDeep Project
In 2017, UpDeep carried out a soil and biogeochemical sampling orientation study at Kangerluarsuk. UpDeep was an EIT (European Institute Innovation and Technology) RawMaterials project funded by the European Union, which focussed on developing low environmental impact surface geochemical exploration techniques to explore for deeply seated mineralisation. Biogeochemical sampling focussed upon two plant species, arctic willow (Salix glauca) and lapland rose (Rhododendron lapponicum) that are ubiquitous throughout Bluejay’s licence areas. Arctic willow is a known hyper-accumulator of zinc, making it an effective sampling medium for Zn-Pb exploration at high latitudes. The resulting data has provided further independent confirmation of Bluejay’s existing drill targets. Elemental ratios from the biogeochemical sampling define anomalies that are coincident with the strongest SGH anomalies previously identified by Avannaa. The strongest signals came from the pathfinder elements, thallium and cadmium.
Geological Survey of Denmark and Greenland
From 2015 to present, a government-funded regional mapping and research initiative (co-funded by the Geological Survey of Denmark and Greenland (GEUS) and the Government of Greenland’s Ministry of Mineral Resources) on the Karrat Group has significantly enhanced the understanding of the stratigraphy, basin architecture and structural evolution of the meta-sedimentary and meta-volcanic rocks of the Karrat Group (that hosts Bluejay’s Kangerluarsuk project). Three new 1:100,000 scale geological map sheets and GIS package for the Karrat Group have been published. The programme has also produced a wealth of new geochronological, geochemical, structural, petrological, hyperspectral and 3D-photogeological data. As a result, several academic papers and MSc research thesis have been published on the Karrat Group in recent years, including studies specifically on mineralisation within Bluejay’s licence area. The deliverables of this programme have allowed Bluejay to further refine the genetic model for the mineralisation at Kangerluarsuk (including an on-going dialogue and collaboration with GEUS).
In collaboration with Camborne School of Mines (University of Exeter, UK), Bluejay has recently completed prospectivity modelling of Kangerluarsuk project, integrating both multivariate principal component analysis (PCA) of the selective leach geochemistry datasets and airborne geophysics to assist with drill target delineation and ranking.
In 2022, Bluejay commissioned Xcalibur Multiphysics to fly a high-sensitivity, fixed-wing FALCON® Airborne Gravity Gradiometer (‘AGG’), magnetic and LIDAR survey over the Kangerluarsuk project. Flight lines were flown at 300 metre spacing for a total of 587 line-kilometres. The state-of-the-art FALCON® system uses extremely sensitive accelerometres to produce low-noise, high-resolution gravity data from an airborne platform, providing several key advantages over other standard Full Tensor Gradiometer (FTG) systems. The AGG data provides a model of the geology based on density variations in the underlying rocks, proving a useful geophysical tool to explore for dense sulphide mineralisation. The sharp density contrast between the known mineralisation (mainly sphalerite, galena, pyrite, pyrrhotite) at Kangerluarsuk and the lower-density metasedimentary host rocks results in identifiable gravity anomalies, indicating the presence of concealed sulphide bodies – even below thick cover. Kangerluarsuk also benefits from the absence of overburden, which can otherwise impact on modelling of gravity data.
Processing and interpretation of the AGG data was completed in-house and by Astrock Oy, Finland and the data fully integrated with all existing electromagnetic, magnetic, geochemical, biogeochemical, and geological datasets for the project. The results have refined and upgraded confidence in existing drill targets at Kangerluarsuk, identified extensions to some anomalies, and assisted in drillhole placement and ranking. Positive gravity anomalies identified by the survey are coincident with conductive bodies recognised in earlier airborne electromagnetic surveys (ZTEM and DIGHEMV) and are independently supported by several geochemical proxies ((MMI, SGH and biogeochemical sampling). Gravity profile modelling indicates the presence of dense bodies close to the inferred basement contact, dipping gently to the southeast. These are interpreted to represent downdip extensions of the “Discovery Zone” & “Discovery Zone South” mineralisation. The results have commercially de-risked the opportunity to strongly justify further progression of the project, through a maiden drill programme.
A maiden drill programme is planned for summer 2023 that will test both deeper combined geochemical and geophysical targets (300-1000m), and the shallower (<300m) extensions to known outcropping mineralisation. Despite extensive, high-grade, outcropping base metal mineralisation, this will be the first time Kangerluarsuk will be drill tested.
Surface exploration will include stream sediment, scree sediment and heavy mineral concentrate sampling; channel sampling of outcropping mineralisation; as well as geological mapping and prospecting for outcropping mineralisation and/or prospective host lithologies.
For more information on the Kangerluarsuk project, please contact Bluejay’s Vice President Exploration, Joshua Hughes (firstname.lastname@example.org)