Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI52O12SE00012

Record: MDI52O12SE00012

General

Commodities

Primary Commodities: Copper, Gold

Secondary Commodities: Molybdenum, Silver

Location

Township or Area: Stoughton Lake Area

Latitude: 51° 35' 45.12"    Longitude: -91° 36' 53.1"

UTM Zone: 15    Easting: 595949.998   Northing: 5716999.998    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 52O12SE

Point Location Description: Precise

Location Method: Conversion from MDI

Exploration History

1960: Diamond drilling by Castlebar Silver & Cobalt Mines in the area between Lang Lake and Saddle Lake. 1968-1972: Bochawna Copper Mines Ltd. and the Hanna Mining Company conducted an extensive exploration program in the area north of Lang Lake, including a diamond drilling program that outlined a copper deposit. 1969-1971: The Algoma Steel Corporation Ltd. conducted extensive diamond drilling and geophysics in northwest of Lang Lake for iron ore. 1969-1970: Card Lake Copper Mines Limited conducted grid mapping geophysics and diamond drilling for gold and base metals in the Saddle Lake, Boyes Lake, Card-Cannon Lakes, and Heinz Lake areas. 1970: Mextor Mineral Ltd. and Kennco Exploration Limited conducted geophysics and diamond drilling for base metals in the Saddle Lake area. 1984-1986: Duration Mines conducted geophyscis, grid mapping and diamond drilling on the southern arm of the Lang Lake greenstone belt for base metals mineralization. 1985-1986: Geological, geochemical and geophysical surveys in the western Lang Lake area by Utah Mines. 1991-1992: Noranda Exploration Company Limited conducted grid mapping, geophysics and diamond drilling for base metals in the Lang Lake and Saddle Lake areas. 2003-2007: East-West Resource Corporation conducted geological and geophysical surveys and diamond drilling of the Lang Lake copper deposit.

Assessment Work on File

Geology

Province: Superior

Subprovince: Uchi

Terrane: North Caribou

Domain: Uchi

Belt: Lang Lake

Geological Age: Neoarchean  

Geology Comments

Mar 29, 2007 (Mark Puumala) - Stott and Corfu (1991) describe the Lang Lake greenstone belt as being dominated by tholeiitic basalt flows and calc-alkalic pyroclastic deposits, with the eastern portion of the belt containing a significant clastic metasedimentary sequence that also includes iron formation horizons. The supracrustal rocks of this belt have been 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 rock sequence. The entire belt has been isoclinally folded into an east-trending and east-plunging syncline (Thomas 1988). Thomas (1988) also indicates that the belt contains two significant intrusions, including an east-west trending mafic stock in the Sor-McVicar Lakes area, and a later north-south trending felsic intrusion in the Shonia-McVicar Lakes area. A number of base metal occurrences have been documented in the western portion of the belt, with a notable porphyry-type copper deposit (Lang Lake Prospect) found within an approximately east-west trending sliver of supracrustal rock mapped by Fenwick (1969) that extends westward into the adjacent granitic intrusions. VMS-type zinc-copper mineralization has also been noted at a number of locations near the northwestern end of the greenstone belt, in close proximity to Saddle Lake. Mineralization types noted in the southwestern portion of the belt adjacent to Lang Lake include gold- and silver/lead-bearing veins. The dominant structural feature in the area is the Bear Head Fault Zone, which is located immediately to the southwest. This is an approximately northwest-southeast striking, regional-scale, dextral shear zone that has been classified by Stott and Corfu (1991) as a transcrustal 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). Weidner (1987) has also mapped an approximately northwest-striking (320) fault that through the central portion of Lang Lake. It is possible that this structure is related to the Bear Head Fault Zone. Fenwick (1969) also mapped a number of approximately east-northeast to east-striking lineaments in the western portions of the greenstone belt. These structures approximately parallel the regional foliation trends and the regional syncline axis, and may represent axial planar shear zones.

Lithology

Mineralization

Mineralization Comments

Mar 29, 2007 (Mark Puumala) - The Lang Lake Copper prospect is located at the west end of the Lang Lake Greenstone Belt. Findlay and Ayres (1977) indicate that this deposit is located in a steeply-dipping north-facing metavolcanic-metasedimentary sequence that has been intruded by equigranular granodiorite stocks and felsic to intermediate dikes that are commonly porphyritic. Findlay and Ayres (1977) have classified this deposit as an example of Archean-age porphyry-type mineralization. Several phases of porphyry have been described by Findlay and Ayres (1977). These include hornblende, quartz-plagioclase and mafic varieties. The oldest of these porphyry phases has been interpreted to be hornblende porphyry that occurs in an approximately concordant southeast-striking zone up to 110 m wide. The quartz-feldspar porphyry has been interpreted to be younger that n the hornblende porphyry and occurs as two separate units located immediately to the north and south. The geological map provided in Findlay and Ayres (1977) indicates that the northern quartz-feldspar porphyry unit parallels the hornblende porphyry and has a similar width. However, the southern quartz-feldspar porphyry unit pinches out to the northwest but becomes substantially thicker than the northern unit toward the southeast. Findlay and Ayres (1977) also describe intrusive breccia dikes (up to 6 m wide) that cross-cut both porphyry types. The youngest porphyry phases are described as relatively narrow (up to 10 m) mafic dikes that approximately parallel the quartz-plagioclase dikes. The adjacent granodiorite intrusions have been interpreted to pre-date the porphyry intrusions and are described by Findlay and Ayres (1977) as being equigranular and medium- to coarse-grained. The sulphide-mineralized zone is approximately 700 m long (trending east-west) and 300 m wide (Findlay and Ayres 1977). Mineralization consists of pyrite, pyrrhotite, chalcopyrite and molybdenite as disseminations or stringers/veins in shear zones and fractures. Silver and gold are also reported to be present in trace quantities. Mineralization occurs within the northern portions of the porphyry intrusions and north of the intrusive contact in the adjacent metasedimentary and metavolcanic rocks. The highest grade mineralization is reported by Findlay and Ayres (1977) to occur within pyroclastic rocks, autoclastic breccias and metasedimentary rocks located immediately north of the porphyry contact. Alteration is reported to be widespread in the vicininty of the deposit and consists of epidote, quartz, chlorite, carbonate, sericite, albite, sphene and clay minerals. The most notable alteration reported by Findlay and Ayres (1977) is a zone of epidote-quartz alteration within the quartz-plagioclase porphyry. Findlay and Ayres (1977) report that the average copper grade in the western half of the deposit ranges from 0.25% to 0.35%, while the average molybdenum grade is approximately 0.005%. Copper grades of over 1% occur locally in zones that are typically less than 5 m wide. Heggie (2006) reports that in 1971, Hanna Mining and Bochawna Copper Mines calculated reserves of 23 million tonnes grading 0.29% Cu to a depth of approximately 150 m. MacDougall (1991) also indicates that the limits of the deposit remain open to the east and northwest. Recent diamond drilling results reported by East West Resource Corporation (news release dated May 18, 2006) are reported to have produced significant gold and silver assays from sections containing the highest copper values (8.99% Cu, 2.08 g/t Au and 61 g/t Ag over 0.3 m in ddh LL06-02).

Mineral Record Details

References

Map - Lang-Cannon lakes area (west half), District of Kenora (Patricia Portion)

Publication Number: P0581 Scale: 1:31,680    Date: 1997

Author: Fenwick K.G.

Publisher Name: Ontario Dept. of Mines

Location:

Mono - Copper, nickel, lead and zinc deposits of Ontario

Publication Number: MDC012 Page: 178-179  Date: 1969

Author: Shklanka R.

Publisher Name: Ontario Dept. of Mines

Location:

Publication - Lang Lake - An Early Precambrian Porphyry Copper-Molybdenum in Northern Ontario; in Report of Activities, Part B, Geological Survey of Canada, Paper 77-1B, p. 25-28.

Publication Number: GSC Paper 77-1B Page: 25-28  Date: 1977

Author: Findlay, D.J. and Ayres, L.D.

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/102747

Article - Uchi subprovince

Publication Number: SV04-01.006 Date: 1997

Author: Stott G.M., Corfu F.

Publisher Name: Ontario Geological Survey

Location:

Article - Regional-scale shear zones in Sachigo Subprovince and their economic significance

Publication Number: MP141.006 Page: 53-67  Date: 1997

Author: Osmani I.A., Stott G.M.

Publisher Name: Ontario Geological Survey

Location:

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