Mineral Deposit Inventory for Ontario

Ministry of Energy, Northern Development and Mines

Permanent Link to this Record: MDI52O11SW00012

Deposit: MDI52O11SW00012


Mineral Deposit Identification
Deposit Name(s) Altered Zone - 1985, East Bay Property - Altered - 2015, McVicar Lake #9 - 1959
Related Deposit Type None
Deposit Status prospect
Date Created 1990-Nov-29
Date Last Modified 2019-Sep-26
Created By Q Unknown
Revised By T Pettigrew


Primary Commodities: gold


Township or Area: McVicar Lake Area

Latitude: 51° 33' 45.59"    Longitude: -91° 23' 32.15"

UTM Zone: 15    Easting: 611441   Northing: 5713623    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 52O11SW

Point Location Description: Assessment file map (McKay 2004).

Location Method: data compilation

Source Map: MCVICAR LAKE (EDITION 1) 52O11

Sources Map Scale: 1:25 000

Access Description: Accessible year round via fixed-wing aircraft or helicopter from the town of Pickle Lake. A winter road from Pickle Lake to the First Nation community of Cat Lake is situated approximately 3 km south of the property. A backhoe trail leads from the winter road to the eastern portion of the property.

Exploration and Mining History

1959-62: Kenlew Mines Ltd. carried out mapping, stripping, trenching, magnetometer and EM surveys, and drilled 4 DDH totalling 221 m. 1985: BHP-Utah Mines carried out mapping, prospecting, airborne EM and magnetic surveys, and ground VLF-EM, mag, and HLEM surveys. 1987: BHP-Utah Mines Ltd. drilled 16 DDH totalling 1356.1 m. 2003: Continuum Resources Ltd. and Prospector Consolidated Resources Inc. carried out stripping, sampling, and drilled 2 DDH totalling 168 m. 2011: Wildcat Exploration carried out prospecting, channel, soil sampling, aeromagnetic, spectrometric, and EM geophysical surveys. 2016-17: Reliant Gold Corp. carried out prospecting and sampling.

Assessment Work on File

Assessment Work on File
Office File Number   Online Assessment File Identifier   Online Assessment File Directory  
2.14235     52O11SW0001     Open
52O11SW0028     52O11SW0561     Open
2.27138     52O11SW2004     Open
52O11SW0047     52O11SW0028     Open Open
2.11011     52O11SW0010     Open
OM91-026     52O11SW0015     Open Open
2.51556     20000007311     Open
2.13125     52O11SW0004     Open
2.27178     52O11SW2003     Open
63.5247     52O11SE0080     Open
52O11SW0038A1     52O11SW0050     Open
52O11SW0033     52O11SW0052     Open
52O11SW0017C1     52O11SW0057     Open
34     52O11SW0018     Open Open
36     52O11SW0023     Open
2.58450     20000015742     Open


Province: Superior

Subprovince: Uchi

Belt: Lang Lake

Geological Age: Neoarchean   

Tectonic Assemblage: Confederation

Structure Name Scale Strike Dip Trend Plunge
Altered Zone Fault East Of Flexure regional 300 45
Altered Zone West Of Flexure regional 330 45
Surface Showing Foliation local 302 43
Zone Of Mineralization local 110 38

Geology Comments

03/29/2007 (M A Puumala) - The area geology is described in MDI52O11SW00007. The dominant structural feature in the area is the Bear Head fault zone, a southeaststriking, regional-scale, dextral shear zone classified by Stott and Corfu (1991) as a trans-crustal megafault. This fault zone extends approximately 515 km from Lake Winnipeg to the northern boundary of the Meen–Dempster greenstone belt (Osmani and Stott 1988). Two other west-northwest-trending deformation zones, referred to as the Lower McVicar fault and Altered Zone fault (McKay 2004), are also present in the area and are associated with a number of gold occurrences. Fumerton (1997) suggested a relationship between the Altered Zone fault and the axial plane of the regional syncline. Fumerton (1997) indicated that supracrustal rocks between the Bear Head and Lower McVicar faults have been folded into sigmoidal S-folds, and that a number of splay faults also exist in this area. The geometry of these structures has been interpreted as being consistent with a dextral sense of displacement (Fumerton 1997).

11/15/2011 (T Pettigrew) - The visited occurrences lie within the Lang Lake greenstone belt, which is dominated by tholeiitic basalt flows and calc-alkalic pyroclastic deposits; the eastern portion of the belt contains a significant clastic metasedimentary sequence that also includes iron formation horizons (Stott and Corfu 1991). The supracrustal rocks of this belt were provisionally assigned to the Confederation assemblage by Stott and Corfu (1991) based on a single age determination from a dacitic tuff in the lowermost (i.e., interpreted to be oldest) portion of the supracrustal sequence. The entire belt was isoclinally folded into an east-trending and east-plunging syncline (BHP–Utah Mines 1988). BHP–Utah Mines (1988) also indicated that the belt contains 2 significant intrusions, including a mafic stock in the Sor–McVicar lakes area, and a later felsic intrusion in the Shonia–McVicar lakes area that hosts several gold occurrences. The Altered Zone prospect is located at the eastern end of McVicar Lake, on the Altered Zone fault, which was described by BHP–Utah Mines (1988) as a northwest-trending ductile shear zone that is refracted north-northwest at a contact between mafic metavolcanic rocks and gabbro. Gold mineralization at the Altered Zone prospect occurs within a dilation zone in the fault structure that developed within this flexure (Puumala 2009). The deformation zone associated with the fault was reported to have a width of approximately 5 to 6 m to the northwest and southeast of the Altered Zone (BHP–Utah Mines 1988). McKay (2004) reported that the Altered Zone is exposed on surface over a total strike length of 150 m. Gold mineralization largely occurs in lenticular quartz ± iron carbonate veins with minor pyrite and rare chalcopyrite. Channel sampling carried out in 2003 returned assay values up to 12.77 g/t Au over 0.8 m. A summary of the results of earlier surface sampling is provided by Janes, Seim and Storey (1991). The main stripped area (UTM Zone 15: 611422 Easting / 5713642 Northing) exposes the east-southeast-trending deformation zone in gabbro. The zone is characterized by shallowly northeast-dipping foliation surfaces and iron carbonatization, sericitization and sulphidization. White, iron carbonate- and sericite-bearing quartz veins up to 2 m wide are boudinaged within this zone and contain finely disseminated pyrite.

Mineral Deposit Lithology

Lithology Data
Rock Type Rank Composition Texture Relationship
vein 1 quartz veins and pods host
gabbro 2 sheared and altered adjacent
mafic metavolcanics 3 sheared and altered adjacent
intermediate intrusive 4 adjacent


Deposit Mineralization and Alteration
Rank Mineral Name Class Economic Mineral Type Alteration Mineral Type Alteration Ranking Alteration Intensity Habit Description
1 pyrite economic ore
2 chalcopyrite economic ore
3 arsenopyrite economic ore
4 pyrrhotite economic ore
5 gold economic ore
1 quartz economic gangue
carbonate alteration carbonatization 1 unknown disseminated
fuchsite alteration hydrothermal 2 unknown disseminated
sericite alteration sericitization 3 unknown disseminated
silica alteration silicification 4 unknown disseminated

Mineralization Comments

03/29/2007 (M A Puumala) - The Altered Zone prospect is located on the Altered Zone Fault, which is described by Thomas (1988) as a northwest-trending ductile shear zone that is refracted north-northwest at a contact between mafic metavolcanics and gabbro. To the southeast of the Altered Zone prospect, the fault strikes approximately 300 through the gabbro intrusion and dips steeply to the northeast. To the north of the gabbro-mafic metavolcanic contact, the fault strikes approximately 330. Gold mineralization at the Altered Zone prospect occurs within a dilation zone in the fault structure that developed within this flexure. The deformation zone associated with the fault is reported by Thomas (1988) to have a width of approximately 5 to 6 metres to the northwest and southeast of the Altered Zone. Within the Altered Zone, the area of deformation is reported to dilate to a with of approximately 20 m over a strike-length of 300m. McKay (2004) reports that the Altered Zone is exposed on surface over a total strike length of 150 m. Foliation in this portion of the shear zone varies in strike from 294 to 310 degrees and dips from 36 to 51 degrees to the northwest. Gold mineralization largely occurs in lens-shaped quartz +/- Fe-carbonate veins. These veins are indicated by McKay (2004) to be mineralized with minor pyrite and rare chalcopyrite. McKay reports that channel sampling carried out in 2003 provided assay results of up to 12.77 g/t over 0.8 m. A summary of the results of earlier surface sampling is provided by Janes, Seim and Storey (1991). Based on the results of an earlier diamond drilling program, Thomas (1988) describes the geology of the Altered Zone as consisting of sheared and/or brecciated basalt and gabbro, quartz-carbonate-sericite schist and apple green mica schist. The deformation zone also hosts significant quartz veining and pods of intermediate intrusive rock. Thomas (1988) indicates that pyrite mineralization occurs throughout the zone (generally 2-5%), and that visible gold also occurs in quartz veins. Gold mineralization also occurs in the altered wall rocks in association with pyrite, with grades generally proportional to the pyrite content. Thomas indicates that the gold mineralized dilation zone likely plunges 30 to 45 degrees to the east-southeast. McKay (2004) has also interpreted surface foliation trends and mineral elongation lineations as being indicative of shallow (15 to 31 degree) eastward to east-southeastward-plunging mineralized veins and ore shoots. In general, Thomas (1988) describes gold mineralization in the Altered Zone as consisting of widespread low-grade gold values interspersed with discrete high grade sections. The most significant assay reported from this zone by Thomas (1988) was 14 g/t Au in a 4.63 m interval of massive quartz from ddh ML-27. Other significant drill intersections are tabulated by McKay (2004).

09/26/2019 (T Pettigrew) - The 2003 stripping program exposed the Altered Zone for 150 m along strike. The width varies from 2.5 to 12.5 m. Extensive sampling conducted within Stripped Area AZ-03-05 indicates that the gold mineralization is localized primarily within discrete, syntectonic "fault-fill" quartz +I- Fe-carbonate veins. These veins are lens-shaped in plan and vary in size up to approximately 3 by 6 m. The veins typically contain trace to minor amounts of pyrite +/- rare chalcopyrite and locally contain narrow ribbons and septa of intensely altered, pyritic gabbro. Channel samples collected across the width of these veins returned assay values of up to 12.77 grams gold per tonne over 0.80 m (Assessment report 52O11SW2003). At trench area #3, weakly altered massive mafic metavolcanics host a series of north-trending intermediate feldspar porphyritic dykes. At the margins of one of the dykes a narrow (<1.5m) shear zone hosts a very narrow (1-10 cm) quartz vein. One grab sample taken from the vein contains 5% sulphides (Py, Po, Cp) and assayed 48,550 ppb Au, later examination revealed the presence of native gold. Trench area 2 is established on a xenolith of mafic metavolcanics within metagabbro. The mafic metavolcanics, in contrast to Trench area 3, are intensely altered with attendant shearing and quartz veining. Quartz veins and boudins in the shear zone are conformable to shearing and range from 0.1 m to 1.0 m in thickness. Extensive channel and grab sampling indicated that gold is principally contained within the quartz veins. The best sample obtained from this area is a grab sample of quartz which assayed 6990 ppb Au. BHP-Utah Mines drillhole ML-02 intersected 12 g/t Au over 0.82 m and DDH ML-18 intersected 7.3 g/t Au over 1.4 m (Assessment report 52O11SE0080). Continuum Resources’ DDH ML-03-01 assayed 5.72 ppm Au over 7.71 m, including up to 22.43 ppm Au over 0.75 m. DDH ML-03-02 assayed up to 1.112 ppm Au over 0.44 m (Assessment report 52O11SW2004).

Mineral Deposit Details

Deposit Classification
Rank Classification            
1 lode (gold)
Deposit Characteristics
Rank Characteristic            
1 vein
2 sheared
3 breccia


Publication - Sioux Lookout Resident Geologist's District - 1990; in Report of Activities 1990, Resident Geologists, p. 67-105.

Publication Number: MP152    Date: 1991

Author: Janes, D.A, Seim, G.W. and Storey, C.C.

Publisher Name: OGS

Map - Precambrian Geology of the Lang Lake Greenstone Belt (West Half)

Publication Number: P3794    Scale: 1:20 000    Date: 2015

Author: Magnus, S.J.

Publisher Name: OGS

Map - Geological Series, Lang-Cannon Lakes Area (Central Part), District of Kenora (Patricia Portion)

Publication Number: P0665    Scale: 1:31 680    Date: 1971

Author: Fenwick, K.G.

Publisher Name: OGS

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