Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI52I08NW00013

Record: MDI52I08NW00013

General

Commodities

Primary Commodities: Lithium, Tantalum, Beryllium, Cesium

Location

Township or Area: Crescent Lake Area

Latitude: 50° 24' 30.91"    Longitude: -88° 27' .92"

UTM Zone: 16    Easting: 396950   Northing: 5585066    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 52I08NW

Point Location Description: Stripped pegmatite in drillhole cluster seen on Google Earth

Location Method: Data Compilation

Access Description: The property is located 42 km east of Armstrong and can be accessed by the all-weather, two-lane, Jackfish main haulage road.

Exploration History

1957: Discovered by prospector Nelson Aubry. 1957: Anaconda Canada drilled 11 DDH totalling 397.5 m. 1968: J. Donner conducted sampling. 1969: Tantalum Mining Corporation of Canada Ltd. conducted geological mapping and sampling, mag and EM ground geophysical surveys. 1979-80: Cominco conducted line cutting, mag ground geophysical surveys, and geological and soil geochemical surveys. 1999: Gary Clark Consulting conducted sampling. The property was staked by Stares Contracting. 2001: Linear Resources optioned the property and conducted line cutting, prospecting, sampling, stripping, trench mapping, and channel sampling. 2002: Linear Resources conducted trenching, lithogeochemistry, prospecting and drilled 23 DDH totalling 1144 m. 2008-09: Linear Metals Corp. conducted line cutting, soil and rock sampling, geological prospecting and mapping, and drilled 12 DDH totalling 1494 m. 2012: Linear Metals changed name to Stockport Exploration Inc. 2016: Stockport optioned the Aubry property to Ardiden Ltd., who drilled 27 DDH totalling 1728 m, 25 of which were on the North Aubry. 2017: Ardiden drilled 40 DDH totalling 4760 m and collected a bulk sample. 2018: Ardiden carried out prospecting and sampling, and drilled 36 DDH totalling 6318 m. 2021: Green Technology Metals entered into a joint venture agreement with Ardiden, acquiring an 80% interest in the property. Baseline environmental studies were initiated. 2022: Ardiden sold its final 20% interest of the lithium joint venture to Green Technology Metals.

Assessment Work on File

Geology

Province: Superior

Subprovince: Wabigoon

Belt: Caribou Lake

Geological Age: Archean  

Geology Comments

Jun 20, 2011 (N Bennett) - The Seymour Lake property is located in the Caribou Greenstone Belt, which trends ENE along the top of Lake Nipigon, near the northern margin of the Wabigoon Subprovince. A prominent SW-trending portion of the belt wraps around the NW end of a large composite felsic pluton in the property area. The Linear Metals claim group (including KM61 claims) covers a large (1 km x 7 km) lensoid-shaped contact zone between the pluton to the south and metabasalts to the north.The pegmatite dikes are associated with the granitic pluton and intrude the mafic volcanics (pillowed lava, amphibolite, and tuff) that make up the majority of the Seymour Lake property. Pillowed lava in TR-NA-5 shows streching in the N-S direction with stratigraphic tops toward the north (after Pye, 1968). Dykes associated with the contact between the metavolcanics and the felsic pluton are generally coarse-grained and contain spodumene, but not tantalite mineralization. Dikes that have injected farther into the metavolcanics and away from the contact are finer-grained and contain beryl, spodumene and tantalite-columbite mineralization. Typical mineralization at the North Aubry pegmatite is an assemblage of muscovite, spodumene, quartz, K-feldspar and albite +/- manganotantalite +/- beryl +/- apatite +/- lepidolite +/- garnet. The South Aubry pegmatite is characterized by spodumene-bearing feldspathic zones, often with accessory blue to green beryl with locally abundant tantalite in the southernmost trenches.

Lithology

Mineralization

Mineralization Comments

Jun 20, 2011 (N Bennett) - The work carried out by Linear in the summer of 2001 demonstrated the economic possibilities for a significant tantalum deposit(s) in the area. The North Aubry vein has been exposed over a +200 m strike length with widths up to 50 m. Values in the TR-NA-5 area at the south end of the zone reach 2.49 % Ta2O5 over 4 m with the tantalum values in the tantalite indicating extreme fractionation. These values are the highest encountered in Ontario and similar to those from the Tanco Mine in Manitoba, Canada's only tantalum producer. Lithium alteration in the mafic volcanics indicates an intense mineralizing pulse which may have produced stacked zones of pegmatites. Exploration at The South Aubry zone, located 600 m to the south of the North Aubry uncovered coarse tantalite mineralization with significant Ta values; for example: a lepidolite bearing boulder located to the south of the South Aubry near TR-SA-4 yielded Ta2O5 values of 541 ppm (0.054 %). The last drill program at Seymour Lake, testing primarily for tantalum, was completed during August 2002 with a total of 1,866 metres of NQ core drilled in 32 drill holes. The drilling tested the North and South Aubry zones, where lithium (spodumene), tantalum (tantalite), and beryllium (beryl) mineralization is found in shallow dipping granite pegmatites over a strike length in excess of one-kilometre. The zones remain open to the north and south and down dip, and other stacked pegmatites have been located in the area. The 2002 drill program tested the North Aubry zone over a 200-metre strike length with 23 shallow vertical holes (SL-02-1 to 16, SL-02-25 to 31), with 21 of 23 holes intersecting pegmatites hosting Li2O mineralization. In the South Aubry area, drilling tested a 380-metre strike length with eight shallow vertical holes (SL-02-17 to 24), all of which intersected Li2O mineralization. The drill intersections are close to true widths due to the near horizontal to shallow dipping nature of the units. While the drilling was targeted primarily at the tantalum potential of the zones, significant lithium mineralization was intersected in the North Aubry zone including: 1.735% Li2O over 14.25m in SL-02-2, 2.386% Li2O over 9.20m in SL-02-4, 0.955% Li2O over 20.65m including 1.190% Li2O over 14.74m in SL-02-9, 2.212% over 5.70m in SL-02-14, 1.325% Li2O over 23.85m including 2.059% Li2O over 9.00m and 2.232% Li2O over 3.04m in SL-02-27, and 1.475% Li2O over 17.72m including 1.937% Li2O over 12.97m in SL-02-31. Although not specifically targeted in the drill program, significant lithium (spodumene) mineralization was also encountered at the South Aubry zone including: 1.460% Li2O over 4.25m including 2.389% Li2O over 1.80m in SL-02-17, 0.757% Li2O over 13.30m including 0.976% Li2O over 4.60m in SL-02-20, 0.648% Li2O over 10.36m including 1.368% Li2O over 2.15m in SL-02-21, and 0.390% Li2O over 7.07m including 1.401% Li2O over 2.92m in SL-02-22.

Jan 22, 2018 (Therese Pettigrew) - The highest tantalum grades were encountered in the southern portion of the North Aubry pegmatite, in the vicinity of trenches NA-5 and 6, where drill holes SL02-15, 28, and 31 all intersected zones of high-grade tantalum mineralization with grades of up to 0.464% Ta2O5 over a one-metre sample width. As defined by drilling, the North Aubry pegmatite has a minimum strike length of 260 m, widths up to at least 200 m, and an average sample composite thickness of 11.52 m. Weighted averages from all drill intercepts of the main body of the North Aubry pegmatite give an overall grade of 0.019% Ta2O5 (AFRI 52I08NW2004). The Seymour Lake area pegmatites have been classified as belonging to the Complex-type, Spodumene-subtype. Mineralization is dominated by spodumene (Li), with lesser beryl (Be), tantalite (Ta), and Rb-bearing potassium feldspar, hosted in a vertically stacked series of gently dipping pegmatite sills (AFRI 20000006547). The North Aubry zone averages approximately 1.467% Li2O (from 22 drill holes applying an arbitrary cut-off of greater than 3 m thickness and a composite grade greater than 0.5% Li2O). Mineralization at the North Aubry zone is dominated by spodumene (Li), with lesser beryl (Be), tantalite (Ta), and Rb-bearing potassium feldspar, hosted in a vertically stacked series of gently east-dipping, shallowly north-plunging pegmatite sills (Assessment report 20000018599). Most holes also intersected significant beryllium (0.010-0.082% BeO), and locally significant tantalum (Rees, 2010). Although up to seven different mineralogical sub-zones of the pegmatites have been described in detail (Dimmell and Morgan, 2005), drilling has shown that the sills can be considered as broadly zoned with a spodumene-quartz-albite bearing core and potassium feldspar rich edges. Spodumene crystals vary from 10 cm in length to as much as 3 to 4 m. Beryl crystals occur throughout the width of the pegmatite, often in very large pale green crystals as much as 0.4 m in diameter. Tantalite occurs as fine to coarse crystals (up to 2 cm in diameter), generally irregularly distributed along strike (local pockets may contain as much as 50% tantalite, i.e. “nuggety”), but concentrated near the albite-potassium feldspar transition (Assessment report 20000017961). The North Aubry pegmatite is 250 m wide by 700 m long with a core ranging from 15 to 43 m thick (Green Technology Metals press release March 8, 2022).

Mineral Record Details

References

Map - Crescent Lake area, Thunder Bay District

Publication Number: M2100 Date: 1997

Author: Pye E.G.

Publisher Name: Ontario Dept. of Mines

Location:

MonoMap - Geology of the Crescent Lake area, District of Thunder Bay

Publication Number: R055 Page: 47-49  Date: 1968

Author: Pye E.G.

Publisher Name: Ontario Dept. of Mines

Location:

Mono - Pegmatite mineral resources of Ontario

Publication Number: IMR021 Page: 48  Date: 1997

Author: Hewitt D.F.

Publisher Name: Ontario Dept. of Mines

Location:

Publication - Technical Report on the Seymour Lake Property

Publication Number: 2010 NI 43-101 Date: 2010

Author: Rees, M.

Publisher Name: Linear Metals Corp.

Location: SEDAR, filed under Stockport Exploration

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For detailed information regarding this mineral record please contact the Thunder Bay North Resident Geologist District Office