Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI52F07SW00006

Record: MDI52F07SW00006

General

Commodities

Primary Commodities: Gold

Secondary Commodities: Copper, Zinc

Location

Township or Area: Lower Manitou Lake Area

Latitude: 49° 22' 24.68"    Longitude: -92° 51' 9.64"

UTM Zone: 15    Easting: 510694.766   Northing: 5468990.357    UTM Datum: NAD83

Resident Geologist District: Kenora

NTS Grid: 52F07SW

Point Location Description: Precise

Location Method: Conversion from MDI

Access Description: The Twentieth Century Mine is located approximately 1.2 km southeast of Jackfish Bay of Upper Manitou Lake, and about 400 m due east of Rector Lake in the Lower Manitou Lake area. The property consists of two shafts and a large dump at the north western corner of Mining Location H.P.399. (MP 142, p. 16; 1989)

Exploration History

Stripping and shaft sinking commenced at the mine site between 1899 and 1900 (Carter 1902). The property was acquired by Twentieth Century Mining Company Limited which sank the main shaft to a depth of 389 feet with 470 feet of drifting and 440 feet of crosscutting between 1901 and 1903. A second shaft, 50 feet east of the main shaft, was sunk to a depth of 50 feet. The mine has been idle since 1904.

Geology

Province: Superior

Subprovince: Wabigoon

Terrane: Western Wabigoon

Belt: Eagle-Wabigoon-Manitou

Geological Age: Precambrian  

Lithology

Mineralization

Mineralization Comments

Feb 22, 2010 (C Ravnaas) - Stripping and shaft sinking commenced at the mine site between 1899 and 1900 (Carter 1902). The property was acquired by Twentieth Century Mining Company Limited which sank the main shaft to a depth of 389 feet with 470 feet of drifting and 440 feet of crosscutting between 1901 and 1903. A second shaft, 50 feet east of the main shaft, was sunk to a depth of 50 feet. Total production from the mine between 1902 and 1903 was approximately 2492 ounces of gold (total value of S43 586) from 8688 tons of ore milled at an average grade of 0.29 ounce gold per ton (Carter 1904, 1905). The mine has been idle since 1904. The Twentieth Century Mine is situated within massive and pillowed mafic metavolcanic flows of the Blanchard Lake Group, overlain by calc-alkalic intermediate to felsic pyroclastics and flows of the Upper Manitou Lake Group (Blackburn 1982). The mine is in close proximity to the contact between the two groups. The mine is also situated on the greenschist facies grade side of the greenschist-amphibolite isograd which lies about 800 m west of the mine, parallel to and imposed by, the Atikwa Batholith, which is northwest of Upper Manitou Lake (Blackburn 1976). According to Carter (1902), lenticular, east trending, gold-bearing quartz veins, up to 25 feet in width, extend parallel to the regional foliation of the mafic metavolcanics at the mine. The author observed dominantly massive and pillowed, dark green, mafic metavolcanic flows, intercalated with thin layers of pyritic interflow metasediments, in the vicinity of the two shafts. A massive, east-trending, biotite- and feldspar-phyric granodiorite dike intrudes the metavolcanic rocks, and can be observed at the second shaft. The dike crosscuts the northeast-trending regional foliation of the metavolcanic rocks. The dike is approximately 1.5 m wide, sericitized, weakly carbonatized, and contains one to two percent disseminated pyrite. Quartz veins and veinlets are hosted within fissile mafic metavolcanic rocks in 0.6 m wide shear zones, which extend along the contacts between the dike and the metavolcanics. Fracture-hosted quartz veins also occur within the granodiorite dike. The mafic metavolcanic wall rock is biotitic and contains minor disseminated chalcopyrite and abundant white calcite along narrow hairline fractures. Alteration is confined to the sheared wall rock and is not wide spread. Granodiorite and metavolcanic wall rock adjacent to the quartz veins may contain up to five percent disseminated pyrite. The quartz veins consist of milk-white quartz, brown iron carbonate, dark green chlorite, and less than one percent disseminated pyrite with variable amounts of chalcopyrite. Carter (1902) also identified sphalerite in the quartz veins. A grab sample of pyritic quartz-vein material taken by the author from the dump at the main shaft contained 1630 ppb gold, while a sample of quartz vein material containing two percent chalcopyrite, taken from the second shaft, analyzed 150 ppb gold. Other samples of wall rock and quartz-vein material, taken in the vicinity of the shafts by the author, analyzed between 9 ppb and 65 ppb gold (Geoscience Laboratories, Ontario Geological Survey, Toronto). (MP 142, p. 16, 17; 1989)

Mineral Record Details

References

Mono - Gold deposits of Ontario, part 1, districts of Algoma, Cochrane, Kenora, Rainy River, and Thunder Bay

Publication Number: MDC013 Page: 158-169  Date: 1971

Author: Ferguson S.A., Groen H.A., Haynes R.

Publisher Name: Ontario Dept. of Mines and Northern Affairs

Location:

MonoMap - Geology of the Lower Manitou-Uphill lakes area, District of Kenora

Publication Number: R142 Page: 64  Date: 1976

Author: Blackburn C.E.

Publisher Name: Ontario Division of Mines

Location:

Mono - Gold deposits of the Kenora-Fort Frances area, districts of Kenora and Rainy River

Publication Number: MDC016 Page: 41  Date: 1976

Author: Beard R.C., Garratt G.L.

Publisher Name: Ontario Division of Mines

Location:

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For detailed information regarding this mineral record please contact the Kenora Resident Geologist District Office