Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI42C13NE00002

Record: MDI42C13NE00002

General

Commodities

Primary Commodities: Copper

Secondary Commodities: Zinc

Location

Township or Area: Olga Lake Area

Latitude: 48° 54' .51"    Longitude: -85° 44' 11.52"

UTM Zone: 16    Easting: 592596.77   Northing: 5417124.43    UTM Datum: NAD83

Resident Geologist District: Thunder Bay South

NTS Grid: 42C13NE

Point Location Description: Pit located approximately 700m north of the northeasternmost arm of Dotted Lake.

Location Method: Field Visit

Access Description: The occurrence is accessible via motor vehicle followed by travel in boat and then on foot. From Manitouwadge, travel south along Highway 614 for approximately 40 km to the Twist Lake logging road. Proceed northeast along the Twist Lake logging road for approximately 4 km to the Dead Otter Lake road. Proceed northeast along the Dead Otter Lake road for approximately 3.5 km to a boat launch located on the southwest shore of Dead Otter Lake. Proceed, via boat, northeast across Dead Otter and Dotted lakes for approximately 6.0 km to the north shore of the northeast arm of Dotted Lake. A poorly marked trail is located approximately 500 m west of the small creek draining into the east end of this arm of Dotted Lake. Proceed north along this trail for approximately 750 m to the vicinity of the occurrence. Sulphides are exposed in a small pit located at the base of a gossanous, slightly elevated outcrop approximately 10 m east of the trail. A grid was cut over the occurrence and the surrounding area in 1991 by Noranda Exploration Company, Limited. The Dotted Lake copper occurrence is located approximately 315 m south of the baseline of this grid and 10 m east of Line 16 East.

Exploration History

1957: Geological mapping; M. Bartley and T. Page ( C.P.R.). 1963-1965: Airborne geophysical survey (EM and MAG); Irish Copper Mines Ltd. This survey delineated one good conductor and a few minor ones. 1964-1965: Geological mapping; V.G. Milne (ODM). 1969-1970: Stripping, trenching and ground geophysical surveys (MAG, EM); prospector T. Macsemchuk. Several weak to moderate conductors were identified. 1978-1979: Regional lake sediment and water geochemical survey; GSC and MNR. Samples collected from near the occurrence contained anomalous amounts of Cu and Zn. 1983-1984: Geological mapping, prospecting soil sampling and ground geophyscal surveys (VLF-EM and MAG); Clear Mines Ltd. Several conductors and magnetic anomalies were identified for follow-up work which was never completed. Airborne geophysical survey (HLEM, VLF-EM, MAG); Aerodat Limited. 1985: Geological mapping; G.M. Siragusa and M.K. Chivers (OGS). 1989: Dighem airborne geophysical survey; Noranda Exploration Company, Limited and Noranda Minerals Inc. (Geco Division) . 1991: Linecutting, geological mapping, ground geophysical surveys (VLF-EM, HLEM, MAG) and diamond drilling (3 holes totalling 502m); Noranda Exploration Company, Ltd. The geophysical surveys identified coincident magnetic and conductive anomalies. 1991: Lithogeochemical sampling; D.B. McKay (OGS). 1991-1992: Reconnaissance till sampling survey; GSC. Samples collected in the vicinity of the occurrence contained anomalous amounts of Cu and Zn.

Assessment Work on File

Geology

Province: Superior

Subprovince: Wawa

Terrane: Wawa-Abitibi

Belt: Schreiber-Hemlo

Geological Age: Neoarchean  

Metamorphism Type: Regional

Metamorphism Grade: Amphibolite

Geology Comments

Dec 07, 2005 (D McKay) - The occurrence is underlain primarily by an east-northeast-trending sequence of amphibolitic, mafic metavolcanic schists and gneisses, quartz- and feldspar-phyric felsic dikes, and banded iron formation. These rocks are moderately to locally strongly foliated, have undergone intense complex folding, and have experienced upper amphibolite facies-grade regional metamorphism. The occurrence is hosted within strongly foliated (280 degrees/60 degrees north), mafic metavolcanic gneiss and ironformation. In the vicinity of the occurrence, the volcano-sedimentary sequence is approximately 800 m wide and is bounded to the north and south by biotite leucogranodiorite of the Dotted Lake batholith. An elongate (2 km long by 300 m wide), body of gabbroic rock is located approximately 500 m south of the occurrence. A north-northeast-trending fault has been inferred to lie approximately 1.1 km to the west of the occurrence. Copper- and zinc-bearing minerals were first noted in the area north of Dotted Lake by prospectors in the late 1950's. Recent geophysical surveys have identified several significant, conductive, magnetic horizons in this area. The most promising horizon is at least 2 km long and hosts both the Fairservice zinc occurrence and the Dotted Lake copper occurrence. This horizon has been interpreted to reflect the presence of sulphides and magnetite within amphibolitized mafic metavolcanic rocks in the area. The strongest conductor within this horizon is located in the vicinity of the Dotted Lake copper occurrence. Several shallow pits have been blasted along the trend of this conductor by prospectors. One of these pits is located on the Dotted Lake copper occurrence. This pit is approximately 4 m long by 1 m wide by 1.5 m deep and is overgrown with vegetation. Grab samples of strongly foliated, sulphide-bearing, mafic metavolcanic rock collected from this pit by Noranda Exploration Company Ltd. in 1991 returned assay values of up to 0.5% copper.

Lithology

Lithology Comments

Dec 07, 2005 (D McKay) - The mafic metavolcanic rocks are rusty-weathering, crudely banded (on a millimetre scale) dark green, fine- to medium-grained biotite-amphibole-quartz-feldspar gneisses and schists. Thin (generally less than 1 cm wide), weakly to moderately magnetic, foliation-parallel, light gray, biotitic quartz-rich bands (interflow metasediments ?) occur intercalated locally with the metavolcanic rocks. These siliceous bands contain 1 to 2% medium- to coarse-grained sulphides as disseminated grains and narrow, foliation-parallel seams.

Mineralization

Mineralization Comments

Dec 07, 2005 (D McKay) - The occurrence, as exposed in the pit, consists of disseminated grains, irregularly shaped patches and narrow (generally less than 1 mm wide) discontinuous, foliation-parallel stringers of medium- to coarse-grained pyrite, pyrrhotite and chalcopyrite hosted primarily in strongly foliated, locally silicified, mafic metavolcanic rocks. The sulphides constitute 1 to 2% of the mineralized rock. Noranda drill hole DDH-91-2 collared approximately 100 m north of the pit described above intersected altered mafic metavolcanic rocks, feldspar porphyry dikes and garnetiferous magnetite-rich iron formation. The mafic metavolcanic rocks are reported to contain up to 8% sulphides (pyrrhotite, pyrite and rare chalcopyrite) as disseminated grains and stringers within a bleached, siliceous zone approximately 4 m wide. The iron formation is reported to be approximately 8 m wide and to contain up to 10% pyrrhotite. No assay results were submitted with the drill log.

Mar 28, 2019 (Therese Pettigrew) - Muir (2000) reports that the showing assayed up to 0.48% Cu and 0.28% Zn from a biotite-amphibole-quartz-feldspar gneiss that contained up 1-8% disseminated and stringered pyrrhotite, pyrite, and chalcopyrite.

Assay Samples

Mineral Record Details

References

Book - National Geochemical Reconnaissance Release NGR 35-1978, Regional Lake Sediment and Water Geochemical Reconnaissance Data, Ontario Eastern Shore, Lake Superior

Publication Number: OF 555 Date: 1979

Author:

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/129524

Map - Geophysical Series, White Lake, Thunder Bay District, Ontario

Publication Number: Map 2168G Scale: 1:63,360    Date: 1963

Author: Geological Survey of Canada

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/116493

MonoMap - Geology of the Black River area, District of Thunder Bay

Publication Number: R072 Date: 1968

Author: Milne V.G.

Publisher Name: Ontario Dept. of Mines

Location:

Article - Schreiber-Hemlo Resident Geologist's District - 1990

Publication Number: MP152.007 Date: 1997

Author: Schnieders B.R., Smyk M.C., Hinz P.

Publisher Name: Ontario Geological Survey

Location:

Book - Regional Lake Sediment and Water Geochemical Reconnaissance Data, Northwestern Ontario

Publication Number: OF 2362 Date: 1991

Author: Friske, P.W.B., Hornbrook, E.H.W., Lynch, J.J., McCurdy, M.W., Gross, H.

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/132202

Map - Dotted Lake sheet, Thunder Bay District

Publication Number: M2146 Scale: 1:31,680    Date: 1968

Author: Milne V.G.

Publisher Name: Ontario Dept. of Mines

Location:

Map - Geological series, Precambrian geology, White Lake (Hemlo) area, Dotted Lake and Black River sections, District of Thunder Bay

Publication Number: P3046 Scale: 1:15,840    Date: 1986

Author: Siragusa G.M., Chivers K.M.

Publisher Name: Ontario Geological Survey

Location:

Mono - Mineral Occurrences in the Manitouwadge Area, Volumes 1, 2 and 3

Publication Number: OFR5906 Page: 33-39  Date: 1994

Author: McKay D.B.

Publisher Name: Ontario Geological Survey

Location:

Publication - Reconnaissance Geochemical Data for Till Samples from the Manitouwadge Area, Ontario

Publication Number: OF 2616 Date: 1993

Author: Kettles, I.M.

Publisher Name: Geological Survey of Canada

Location: https://doi.org/10.4095/183942

File - Schreiber-Hemlo Resident Geologist Mineral Deposit Files

Publication Number: Min Dep Date:

Author:

Publisher Name:

Location: Thunder Bay RGP

Map - Manitouwadge-Wawa sheet, geological compilation series, Algoma, Cochrane, Sudbury and Thunder Bay districts

Publication Number: M2220 Scale: 1:253,440    Date: 1972

Author: Milne V.G., Giblin P.E., Bennett G., Thurston P.C., Wolfe W.J., Giguere J.F., Leahy E.J., Rupert R.J.

Publisher Name: Ontario Division of Mines

Location:

Map - Geological Compilation of the Eastern Half of the Schreiber-Hemlo Greenstone Belt

Publication Number: M2614 Scale: 1:50,000    Date: 2000

Author: Muir T.L.

Publisher Name: Ontario Geological Survey

Location:

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