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Dundas Ilmenite Project - Moriusaq West and East, Iterlak West and East |
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Greenland |
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Ti
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The Dundas Titanium Project is a palaeoplacer, ilmenite-rich black sands/heavy mineral (HM) deposit, developed along a 30 km stretch of coastline in the Pittuffik region of northwestern Greenland. It is located on the southwestern coast of the Steensby Land Peninsular, adjacent to the closed settlement of Moriusaq (or Moriussaq), 30 km northwest of the US Air Force Thule base and early warning radar facility, and 30 km SSW of the larger settlement of Qaanaaq (#Location: 76° 45' 4"N, 69° 47' 55"W).
The Dundas Project incorporates, from NW to SE, over a 20 km interval, the Moriusaq West and East, and the Iterlak West and East onshore raised beach and delta deposits. It lies near the centre of the Thule Black Sands Province that extends along the coast for several hundred kilometres, from Kap Alexander in the north, to Kap Edvard Holm in the south.
Resources estimated to 2024 are restricted to onshore sands of the active and raised beaches and deltas to streams eroding these beaches. The
possibility of offshore placers in the surf and nearshore zones to a water depth of 35 m below present day sea surface has been investigated by limited vibracore drilling and seismic lines and an Exploration Target estimated.
As detailed in the Basement Geology section below, substantial Neoproterozoic basaltic sill-dyke complexes directly underlie and occur in the immediate hinterland of these ilmenite-rich sand accumulations. These intrusions, which have been deeply weathered and disaggregated to sand, have been shown to carry almost double the levels of contained ilmenite as the immediately overlying heavy minerals sand resource. Some 74 samples collected from these sills averaged 11.12% ilmenite (Bluejay, 2024), compared to the resource grade of 6.1% ilmenite within the Project's raised and active beach deposits. These sills are being investigated as a potential additional ilmenite resource, making them potentially amenable to mining in the immediate footwall of and adjacent to the ilmenite sand resource.
These weathered and disaggregated ilmenite-rich sills are taken to be the source of ilmenite in the beach sands, having been eroded and transported to the coast, diluted by detritus from the enclosing sedimentary country rocks, before being re-concentrated by wave and wind action along an alternating prograding and regressing beach front.
Iron sands were first reported in the area by Koch in 1916 (Dawes 1989). The Geological Survey of Greenland undertook investigations and sampling of these heavy mineral sands on several occasions from 1950 (Ghisler & Thomsen 1971). Greenex A/S was granted an exploration licence on 20 May 1985 and carried out spot sampling of sands around Moriusaq in pits before relinquishing the title on the 31 December 1986. QIT-Fer et Titane Inc. was granted a neighbouring exploration licence on 30 May 1985, but difficulty in access due to the temporary closure of the Thule Airbase affected planned fieldwork and the licence was relinquished on the 31 December 1986. In 2010 Hunter Minerals Pty Ltd. was granted an exploration licence over the Moriusaq/Steensby area and mounted a small field campaign
between 26 August and 2 September that year involving small pick and shovel pit sampling. A lightweight hand-operated auger drill was also employed with limited success due to the presence of pebbles cobbles and boulders in the host profile obstructing the drilling. Microprobe analysis of ilmenite and magnetite grains from sample concentrate were conducted in the laboratory. The license was subsequently relinquished. In 2015, FinnAust Mining plc, which later became Bluejay Mining plc, was awarded an exploration licence and commenced investigations. Work included 190 x shallow auger holes in 2016, 261 x shallow auger and Sonic holes in 2017 and 201 sonic holes in 2018, for 1500 m of drilling, with an average hole depth of 2.32 m. These were the basis of a Mineral Resource Estimate and a Pre-Feasibility Study. A maiden Exploration Target estimate was also prepared for offshore, inundated heavy mineral sand ilmenite resources. In December 2020, the Government of Greenland granted Bluejay's application for an Exploitation Licence over the Dundas Ilmenite Project for 30 years.
However, one of the recommendations in the 2019 Pre-Feasibility Study was that further drilling should be carried out to improve the levels of confidence in the Mineral Resource Estimate. To this end, 153 Geoprobe holes were drilled, employing a range of drilling methods (i.e., direct push, diamond drilling, hollow auger, etc), in an attempt to obtain more reliable grade and thickness data than from the auger and sonic drill program. A total of 395 m was drilled, with an average hole depth of 2.58 m. This drilling was supported by a detailed Digital Terrain Model survey and other measures, carried out in 2022, after delays due to the COVID Pandemic restrictions. As a result of this work, an amended Mineral Resource Estimate was presented in 2023 which substantially downgraded the Mineral Resource and Ore Reserve and in section of the deposit. See the 'NOTE' in the Resources and Targets section below for details.
In response to this downgrade of Ore Reserves, the Bluejay board decided it was not in the interests of the Company and its shareholders to progress the Dundas Project as a sole developer. They consequently began a search for a new partner and did not commit further exploration or development capital to the project. In September 2024, the Company's name was formally changed from Bluejay Mining plc to 80 Mile Plc. Further work was carried out under contract by SRK Exploration Ltd during 2024, tasked with evaluating existing data to develop an independent maiden JORC Exploration Target for strongly weathered and disaggregated ilmenite-bearing hard rock sills at the Dundas Ilmenite Project. The aim was to add to the resource and leverage the same infrastructure to be used by the planned HM sand mining operation.
Basement Geology
Basement to the Cenozoic beach and deltaic facies of the Thule Black Sands Province, and the Dundas Project resource, comprise Archaean and Palaeoproterozoic gneiss-supracrustal rock complexes, unconformably overlain in the northwestern quarter of Greenland by the Mid Meso- to Late Neoproterozoic Thule Basin. These are, in turn, unconformably overlain by the extensive intracratonic sedimentary succession of the Lower Palaeozoic to Devonian intracratonic Franklinian Basin to the north. The latter basin laps onto the northern margin of Greenland and extends to the west and north across the Canadian Arctic islands. The Thule basin also formed as an intracontinental rift and sag depocentre into which the Thule Supergroup was deposited as an at least 6 km thick fluvial to shallow-marine succession with associated tholeiitic volcanism. This sequence is largely un-metamorphosed and un-deformed. The Thule Supergroup is composed of four groups, of which the third from the base is the probable early Neoproterozoic Dundas Group. This group, which contains microfossils that suggest a late Mesoproterozoic, Ectasian or Stenian, to early Neoproterozoic, Tonian age, is estimated to be at least 2, and possibly as much as 3 km, thick. It forms the basement to the Dundas palaeoplacers between the coast and the permanent ice sheet that is variably <5 to >20 km inland. It is composed of a monotonous sequence of sandstone, siltstone and shale with lesser carbonate, mainly dolostone, limestone and arenaceous dolostone with chert and evaporitic beds. It includes facies that are thin bedded and dominated by variably pyritic black shale in which carbonate beds with stromatolitic reefs occur (GEUS, 2006).
The Dundas Group is characterised by prominent basaltic sill-dyke complexes of both 1.2 to 1.0 Ga Mesoproterozoic (D1) and 750 to 650 Ma Neoproterozoic (D2) age. The latter, the Steensby Sill Complex, have an anomalous high titanium content of up to 6% TiO2 in whole-rock analysis. The prominent basic sill complex is cut by an intense swarm of roughly coast-parallel, i.e., WNW-trending, high-TiO2 tholeiitic basalt dykes. These dykes are dominantly oriented WNW-ESE and mostly have vertical or sub-vertical dips of between 75°N and S. The thickest of the dykes is ~150 m wide. They are largely aligned parallel to the regional structural grain, particularly the faults associated with the half-grabens of the Thule rift system (GEUS, 2006).
Approximately 15 master sills make up the complex, and comprise between 30 and 40% of the thickness of the stratigraphic section. In the outer coastal area, basaltic rocks constitute up to 50% of the total bedrock exposure. The general dip of the sills and host strata is gentle, up to 10°SW. The thickest of the sills is >100 m, with most sills estimated by historical work to be between 20 and 50 m (Dawes, 2006). They generally extend up to 5 km in one direction and taper in thickness towards the edges. These sills are described as being deeply weathered, particularly in flat tableland areas, where the upper chilled margins have been removed by erosion, leaving behind gabbroic cores that have disintegrated into coarse sand. These sills are rich in opaque minerals, with ilmenite concentrations reaching up to 15% by volume. A linear cluster of multiple stacked, weathered sills is developed along the coast, underlying and in the immediate hinterland of the raised beaches that constitute the main onshore resource. The sills in the project area vary in thickness from a few, up to >30 m, with lateral continuities up to several kilometres (GEUS, 2006).
The D2 dykes have comparable chemistry to the D2 sills and, as mentioned above, are also exceptionally rich in TiO2. Some 12 representative samples of both dykes and sills were collected for comparison by Dawes (1989). Four sill samples averaged 5.3% TiO2, ranging from 4.7 to 6.0% TiO2. Eight dyke samples averaged 4.9% TiO2, ranging from 4.5 to 5.2% TiO2. Further sampling by Dawes (1989) indicated grades ranging from 3.68 to 5.25 wt.% TiO2.
Palaeoplacer Geology
The Thule Black Sands Province extends over an interval of almost 200 km along the coast of northwestern Greenland. The best concentration of black
sand is immediately north-west of Thule Air Base, where a flat uplifted plain that is as much as 3 km wide is dominated by alluvial and littoral deposits. It is bounded along the coast by ~80 km of active sandy beaches that are up to ~10 m wide (Dawes 1989). However, from an economic perspective, the most extensive and best grades are found along the adjacent south-east trending coastline around the former settlement of Moriusaq and are the basis of the Dundas Project.
The coast in the Moriusaq area hosts uplifted beaches with ilmenite rich heavy mineral sand occurrences within extensive flat coastal plains at an elevation up to 40 m above current sea level. These uplifted or raised beaches occur as flat-topped benches, often with distinct frontal scarps, and are up to 1 km wide and persist for ~20 km parallel to the coast, and up to 1.2 km inland. These raised beaches are composed of graded and bedded deposits of cobbles, pebbles, sand and some silt. In many places there has been reworking of these deposits by fluviatile processes and several wide water courses cross the plain, producing fluvial, delta and outwash concentrations, as well as areas of grey marine silts. These raised beach deposits usually bottom in cobbles or permafrost, underlain by Dundas Group sediments or the basaltic sill-dyke complex.
The old, raised beaches appear to have much less dark, heavy minerals than the active shoreline, and as such have a lower grade of ilmenite, as discussed below. The active beaches vary in width and extent, being up to 10 m wide, although these are broken by areas where basaltic rock outcrops forming a craggy coastline. Where well developed, the active sandy beaches seem to extend seaward below tide level. This is consistent with geophysical that surveys indicate a further considerable volume of unconsolidated sediment is present immediately offshore in the same area. The dominant factor controlling the sedimentary processes governing deposition of these sediments has been sea level change over time. Three facies have been identified, straddling the shore line: i). the highstand systems tract that is exposed inland from the current shoreline and sea level, and tapers down dip from the current coast. This hosts the onshore resource; ii). the lowstand systems tract that is entirely offshore and below the current sea level; and iii). the transgressive systems tract between the current low and high tide marks that transgresses across the other two tracts.
The raised beaches are within the highstand systems tract and have been left stranded by the lowering of sea level. The current active beaches are also sandy and carry ilmenite-rich heavy mineral concentrations over an intertidal width of up to 10 m, although in places may be wider, depending on coastal morphology and bathymetry. The most conspicuous exposures of black sands occur on the active beaches, with the darkest sands being concentrated in diffuse layers that are up to 50 cm thick, whilst lighter coloured sandy beaches can be streaked with concentrations of dense black sands. The black sands on the uplifted beaches are composed of much coarser material and in general, contain a lower concentration of heavy minerals (Dawes 1989).
The mineralogical composition of some of the darkest sands indicates up to 95% opaque fraction, of which >70 wt.% is ilmenite. The composition of the opaque fraction is notably constant and the ilmenite is 'clean' showing no exsolution or microscopic intergrowth. The chemical compositions of ilmenite separated from six sand samples from Steensby Land contain an average of ~46% TiO2 and 38.5% Fe Total (Dawes, 1989). Another ilmenite from a raised beach, 200 m inland at Moriusaq West assayed
45.5% TiO2,
38.8% Fe Total,
0.4% Al2O3,
0.14% CaO,
0.86% MgO,
0.61% MnO,
1.03% SiO2,
0.06% Cr2O3 and
0.39% V2O5 (Dawes, 1989).
As mentioned above, active beaches have higher grades, averaging 43%, ranging from 41 to 44% TiO2 (3 samples; Dawes 1989), whilst raised beaches averaged 12%, ranging from 6 to 23% TiO2 (13 samples; Dawes, 1989)
Active, raised and offshore beach sands are dominantly composed of ilmenite, magnetite and titanomagnetite with accessories that include zircon, sphene, garnet, diopside, hypersthene, hornblende, epidote and sillimanite. The sands that constitute the resource have a size fraction distribution averaging: 24.8% >5 mm; 33.4% >2 and <5 mm; 35.7% >63 µm and <2 mm; and 6.1% <63 µm; with 25.9% Total Heavy Minerals.
The mineable heavy mineral sands on the raised beaches would appear to be <2 m, generally ~1 m thick, based on the depth of drilling. The active beaches include up to 50 cm thick layers of black ilmenite bearing sands and HM-streaked paler sands.
Resources and Targets
JORC Compliant Mineral Resources at the various sections of the deposit within the Dundas Project were as follows (Bluejay Mining plc 29 May 2019, Onshore and Maiden Offshore Resource Update at Dundas Ilmenite Project):
Indicated Mineral Resource
Moriusaq East and West - 88.0 Mt @ 27.0% THM, 3.1% TiO2 Total
Interlak East - 19.5 Mt @ 22.2% THM, 2.2% TiO2 Total
Interlak West - 4.8 Mt @ 11.9% THM, 1.0% TiO2 Total
TOTAL Indicated Resource - 112.3 Mt @ 25.5% THM, 2.8% TiO2 Total
Inferred Mineral Resource
Moriusaq East and West - 5.0 Mt @ 34.2% THM, 4.4% TiO2 Total
TOTAL Indicated + Inferred Resource - 117.3 Mt @ 25.9% THM, 2.91% TiO2 Total = 6.1% Ilmenite
THM = Total Heavy Minerals.
A JORC Compliant Ore Reserve was reported in 2019 from within the Moriusaq sections of the deposit (Bluejay Mining plc, 27 June 2019 - Summary of Pre-Feasibility Study for the Dundas Ilmenite Project), as follows:
Probable Ore Reserve - 67.1 Mt @ 3.45% TiO2 Total = 7.3% Ilmenite in situ.
NOTE: The Pre-Feasibility Study (PFS) for the Dundas Ilmenite Project of 27th June 2019 recommended further drilling should be carried out at Dundas to improve the level of confidence in the Mineral Resource Estimate to enable the PFS 2019 to be brought to Bankable Feasibility Study standard. As a consequence, a program was initiated during the summer of 2022 (following lifting of the COVID Pandemic restrictions), on the Moriusaq West section of the deposit only, to enhance confidence in the ore grade and distribution. This included i). a more detailed Digital Terrain Model survey, ii). twinning of existing auger and sonic drill-holes within a program of 153 new holes drilled by alternative drilling methods, iii). mapping of basement outcrops and alluvial washouts, iv). new bulk sampling, and v). recognition of a series of domains within the resource influencing the distribution of geological, physical and grade characteristics. Unexpectedly, the Mineral Resource Estimate at Moriusaq West, as presented in 2023 (Bluejay Mining plc, Dundas Project Update 21 September 2023), downgraded the Mineral Resource in that section of the deposit from 59.3 Mt @ 3.26% TiO2 Total, to 29.7 Mt @ 1.99% TiO2 Total. This also affected the Ore Reserves, which are principally in the Moriusaq West section of the deposit. As of the end of 2024, no further drilling of the Moriusaq East, Interlak East and West sections to be consistent with those of Moriusaq West, had been undertaken (Bluejay Mining plc 21 September 2023, Dundas Ilmenite Project Update). However, questions were raised and debated as to the accuracy of the revised estimate based on reported problems with the alternative drilling methods utilised. The Bluejay Board initiated a review of the 2023 revised estimate, and in 2024 re-instated the 2019 Mineral Resource Estimate detailed above (Bluejay Mining plc, Dundas Ilmenite Resource Update 16 April, 2024).
In addition to these Mineral Resources, JORC Compliant Exploration Targets have been estimated for hardrock ilmenite and offshore HM sand mineralisation in the Company's existing Mining Licence. These are estimates of the remaining exploration potential, quoted as a range of tonnes and a range of grades, based on exploration results, but for which there has been insufficient exploration to estimate a defined Mineral Resource.
• Offshore Heavy Mineral Sands Exploration Target within the existing Mining Licence - 300 to 530 Mt @ 0.2 to 2.3% TiO2 Total (Bluejay Mining plc - 29 May 2019 - Resource Update at Dundas Ilmenite Project);
• Onshore 'Hardrock' Exploration Target within the existing Mining Licence - 170 to 540 Mt @ 4.7 to 5.5% TiO2 Total (80 Mile plc - 22 September, 2024 - Maiden Exploration Target for Hardock Ilmenite at Dundas).
The most recent source geological information used to prepare this decription was dated: 2024.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
Dundas - Moriusaq West
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Dawes, P.R., 1989 - The Thule black sand province, North-West Greenland: investigation status and potential: in The Geological Survey of Greenland, Open File Series No. 89/4 19p.
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GEUS 2024 - Moriusaq West - Dundas: in Geological Survey of Denmark and Greenland Greenland Mineral Resource Portal Occurrence data sheet 6p.
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GEUS 2006 - Explanatory notes to the Geological map of Greenland, 1:500 000, Thule, Sheet 5,: in Geological Survey of Denmark and Greenland Map Series. 2, 97p.
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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