Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI000000001166

Record: MDI000000001166

General

Commodities

Primary Commodities: Nickel, Platinum, Palladium, Copper

Secondary Commodities: Gold

Location

Township or Area: Nemeigusabins Lake Area

Latitude: 53° 33' 14.98"    Longitude: -89° 52' 21.66"

UTM Zone: 16    Easting: 309714   Northing: 5937758    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 53H12

Point Location Description: Location of DDH BT-87-12 from a map from Roscoe Postle Associates Inc (Sept 26, 2000) for Platinex

Location Method: Based on Assessment

Access Description: The property is located 580km north of Thunder Bay and 230km north of Pickle Lake. Access is by float-equipped aircraft or by winter road. The closest all weather road extends north from Pickle Lake within 160km of the property.

Exploration History

1912: Reconnaissance scale mapping by J.B. Tyrrell of the Geological Survey of Canada. 1964: Ontario Department of Mines reconnaissance scale mapping by P.P. Hudec. 1970: The Canadian Nickel Company (Canico) drilled 6 holes totalling 853 m. 1971: Ontario Geological Survey completed more detailed mapping by Thurston. 1973-75: Canico drilled 16 DDH totalling 3832 m. 1980: Canico drilled 6 DDH totalling 2739 m. 1980-1982: Canadian Occidental Petroleum Ltd (Canoxy) conducted ground magnetic and VLFEM geophysical surveys, geological mapping and prospecting, geochemical studies and drilled 11 holes. 1985-1989: International Platinum Corporation (IPCO) 11,885m of drilling (54 holes). In 1986, upon merging with Silver Lake Resources Inc., Platinum Exploration Canada changed its name to International Platinum Corporation (IPCO) and later in 1995, to International Precious Metals Corp. (IPM). March 23, 1987, IPCO and Fuellstoff Gmbh (Degussa) of Frankfurt, Germany, formed a joint venture whereby Degussa would earn 50% interest in certain exploration properties including the Big Trout Lake Property. In December 1987, a new joint venture was formed including Jenkim Investments Ltd. (Jenkim) along with IPCO and Degussa. 1997: IPCO carried out a Max-Min II EM survey in 1997. 1998: the property rights were transferred to Mr. J. R. Trusler, and in 1999 from Mr. J.R. Trusler to Platinex Inc. 2000: Platinex carried out an airborne EM and magnetometer survey. 2006: Platinex had plans to start a 24 hole drill program but their work was opposed by the Kitchenuhmaykoosib Inninuwug (KI) First Nation. On Dec.13, 2009 Ontario entered an agreement with Platinex to purchase the Big Trout Lake property. The property has been surrendered to the province as part of the agreement and the company was granted $5,000,000 plus mediation costs and a 2.5% Net Smelter Royalty on the former property.

Assessment Work on File

Geology

Province: Superior

Subprovince: Sachigo

Terrane: North Caribou

Geological Age: Archean  

Geology Comments

Mar 24, 2011 (N Bennett) - The Big Trout Lake Property covers parts of the Big Trout Lake ultramafic-mafic intrusive complex (BTL Complex) which is situated within the God's Lake Subprovince of the Archean Superior Structural Province of the Canadian Shield. The BTL Complex appears to comprise two separate sills. The western and central parts of the complex are underlain by poorly exposed ultramafic to mafic intrusive sequence of the Nemeigusabins Lake Arm, which comprises basal peridotite, pyroxenite, dunite and chromitite rich layers in its eastern part, and an upper gabbroic and anorthositic sequence in its western part. The second sill is hosted by the central arm and by the north arm of the BTL Complex. Platinum Group Element (PGE) mineralization has been encountered along a 6 km long trend of a magnetic high defined by several “thumbprint” magnetic anomalies within the Big Trout Lake ultramafic-mafic intrusive complex. Two anomalous trends of PGE, termed the East Zone and the West Zone, have been recognized. Mineralization ranges from 0.6 g/t combined PGE over 1 m to 8.4 g/t combined PGE over 2.3 m in the East Zone while in the West Zone, PGE mineralization occurs as 200 ppb to 500 ppb combined Pt and Pd over 2 m to 60 m.

Lithology

Lithology Comments

Aug 16, 2018 (Therese Pettigrew) - The Big Trout Lake property covers a 19-kilometre strike length of layered mafic and ultramafic intrusive rocks on the Nemeigusabins Arm of the Big Trout Lake Igneous Complex. Over 99 percent of the property is drift covered hence the current geological interpretation relies almost entirely on geophysical and diamond drill hole data. In the area of Nemeigusabins Lake the intrusive is 1,850 to 2,402 metres thick consisting of an ultramafic basal sequence 300-600 m thick, overlain by a 515 m thick gabbroic zone which includes a 26.7 m wide layer of pyroxenite, and a 1,200 metre thick anorthosite zone which includes two distinct pyroxenite layers above and below the 62 m thick West Zone anorthosite. A thin 15-20 m upper ultramafic horizon at the upper contact with the enclosing metavolcanics and metasediments of the Big Trout Lake greenstone belt is a hybrid roof zone rock unit. The basal ultramafic layers of the intrusion have been variably but strongly serpentinized. Identification of the protolith sequence except for chromitite horizons is difficult (AFRI 20000000256).

Mineralization

Mineralization Comments

Aug 16, 2018 (N Bennett) - Mineralization was intercepted in DDH BT-87-12 from 142-143m and is as follows: 179 ppb Pt, 668ppb Pd, 19ppm Au, 744ppm Ni, 144ppm Cu, 0.26% Cr. From 277m to 278m: 231ppb Pt, 756ppb Pd, 19ppb Au, 4339ppm Ni, 752ppm Cu, 0.04% Cr. From 278m to 279m: 491ppb Pt, 2,110ppb Pd, 45ppb Au, 4360ppm Ni, 12,10ppm Cu, 0.05% Cr. From 279m to 282m: 81ppb Pt, 254ppb Pd, 11ppb Au, 2520ppm Ni, 45ppm Cu, 0.04% Cr. An electron microprobe analysis of two chromite-rich one-metre long samples from Canoxy Hole CO 81-02. This two-metre composite interval has assayed 2.16 glt Pt, 6.345 glt Pd and 0.433 glt Rh. The mineralization was identified as Sperrylite (PtAs2), Gerrosite (PtSb2), Hollingworthite (RhAsS) and a compound of iridium and ruthenium with arsenic and sulphur in discreet grains between 1 and 20 microns in size. In 2000 a sample from IPCO's drill hole BT 89-16 was collected from a one-metre interval that, while containing 4.7 glt combined Pt and Pd, the entire intersection contains no visible sulphides or chromite (AFRI 20000000256).

Aug 16, 2018 (Therese Pettigrew) - In 1981 Canadian Occidental Petroleum intersected 7.8 grams platinum group elements (PGE) over a two-meter drilled section associated with a chromitite horizon in the basal Ultramafic Zone of the complex. Since that time numerous drill intersections of PGE mineralization have been returned from the property. A total of 57 core samples from 32 drill holes on the property contain greater than 1 ppm Pt+Pd combined. Mineralization has been drilled over a strike length of at least 4.25 km. A recent study has used the chemical signature of the igneous stratigraphy to identify five major cycles within the Ultramafic Zone of the intrusion on the property. The character of each of the igneous cycles from base to top is summarized below (after Burden and Walls, 2004). Cycle 1: The lowermost cycle over most of the property, it is present only in the Nemeigusabins Lake area and south. Thickness 30 m in the north and up to 170 m in the south. Elevated Cr, Ni and Cu contents at or near the footwall contact. Chromium and copper concentration are low and invariant. Cu:Pd ratios indicate sulphide depletion within this cycle. No significant PGE horizons are attributed to this cycle. Cycle 2: Consistently higher Ni content than Cycle 1 reflecting an increase in olivine content. Dunite-rich layers with associated elevated contents of Cr and PGE. Cu concentration is highly variable within a range of 100 to 3000 ppm. Ni:Cu ratio is low and invariant. A chromitite horizon occurs at the top of the cycle (designated the alpha horizon). Hole BT 89-30 contains 1.3 g/t Pt + Pd + Au over 4 m with high Cu, averaging 1455 ppm over the same interval. In drill hole BT 89-14 this chromite-associated horizon contains 12.8 ppm Pt+Pd (combined over 1 m interval). South of BT 89-14 (2.3Km) where Cycle 1 dramatically thickens, the chromite concentration in Cycle 2 also decreases. Cycle 3: From the base of the cycle an initial increase in Ni content of the rocks reflects olivine rich stratigraphy. Cu concentrations are moderately high at the base, but the unit is characterized by the uniformly low «30ppm) Cu content. A horizon (designated the phi horizon) contains chromitite seams and is associated with the first of two Ni concentration peaks, which occur near the base of Cycle 3 above the alpha horizon. The phi horizon occurs two kilometres north of Nemeigusabins Lake in hole BT 89-22 where a 0.3 m interval contains 6.26 percent Cr and 417 ppb combined Pt+Pd. A chromite-rich horizon identified as the gamma horizon is associated with the second Ni concentration peak. In hole BT-98-22, the gamma horizon contains 8.4 ppm combined Pt+Pd over 2.3 metres (14 g/t over 0.9 m) in a layer that contains 8.73 percent Cr over 3.3 m. Cycle 3 is the main target for a chromitite horizon hosted “reef” type PGE deposit. Cycle 4: This cycle is characterized by a slight Ni content increase and a general increase in the Ni:Cu ratio. Near the top of the cycle is a double peak of both Ni and Cu concentrations accompanied by a significant elevation in PGE values. A Pt: Pd ratio reversal from less than to greater than one occurs within this zone. Cycle 5: The base of this cycle is characterized by an increase in the Ni content. Above the base is a zone of significant chromium enrichment. The top of this uppermost cycle in the area of 22+00S appears to have been scoured by the overlying gabbroic rocks. It was observed by staff of R.J. Burnside & Associates Ltd. that most of the best PGE intersections are associated spatially with chromitites and also are partly within or adjacent to shears, vuggy areas, areas of moderate to intense weathering and core loss in the order of 3 percent to in excess of 10 percent (AFRI 20000000256).

Mineral Record Details

References

Map - Big Trout Lake-North Caribou Lake, geological compilation series, Kenora District

Publication Number: M2292 Scale: 1:253,440    Date: 1974

Author: Bennett G., Riley R.A., Thurston P.C., Siragusa G.M., Sage R.P.

Publisher Name: Ontario Division of Mines

MonoMap - Geology of Winisk Lake area, District of Kenora, Patricia Portion

Publication Number: R193 Scale:     Date: 1980

Author: Thurston P.C., Sage R.P., Siragusa G.M.

Publisher Name: Ontario Geological Survey

MonoMap - Geology of the Big Trout Lake area, District of Kenora (Patricia Portion)

Publication Number: R023 Scale:     Date: 1997

Author: Hudec P.P.

Publisher Name: Ontario Dept. of Mines

Mono - Chromite deposits in Ontario

Publication Number: S055 Scale:     Date: 1986

Author: Whittaker P.J.

Publisher Name: Ontario Geological Survey

Mono - Platinum group elements in layered intrusions, the geology and geochemistry of the Big Trout Lake layered intrusion, Thunder Bay District

Publication Number: OFR5584 Scale:     Date: 1986

Author: Borthwick A.A., Naldrett A.J.

Publisher Name: Ontario Geological Survey

Mono - Chromite deposits in Ontario

Publication Number: OFR5306 Scale:     Date: 1980

Author: Whittaker P.J.

Publisher Name: Ontario Geological Survey

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