Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI42L04SE00005

Record: MDI42L04SE00005

General

Commodities

Primary Commodities: Gold

Secondary Commodities: Copper, Silver, Bismuth

Location

Township or Area: Coughlan Lake Area

Latitude: 50° 2' 50.47"    Longitude: -87° 35' 21.69"

UTM Zone: 16    Easting: 457804   Northing: 5544062    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 42L04SE

Point Location Description: Minesite

Location Method: Conversion from MDI

Access Description: The mine is located northwest of Onaman Lake and south of Oboshkegan Township, between Onaman Lake and Onaman River. The Tashota-Nipigon Mine is accessible via the Camp 40 Road north to the Con Lake Road. Proceed northeast from the Con Lake intersection on the Mine Road for approximately 12 km to the mine site.

Exploration History

1923: J. McKechnie discovered visible gold in sheared metavolcanics. Claims were staked. 1924: Nipissing Mining Co. optioned the property and carried out some diamond drilling. 1927: Tashota Gold Mines Ltd. was formed and acquired Nipissing Mining. Surface stripping and test pitting were completed. 1938: A mining plant was hauled to the site via winter road from Tashota. A 68 m 2 compartment shaft was sunk. Levels established at 30 m and 60 m. 1929-30: Underground dev't con't. Surface and underground drilling were done. 1930: Operations were suspended in March. Operations resumed from September 1931 to March 1932. 1934: Tashota Goldfields reopened the property in April and shaft sinking resumed to 112 m. A third level was established. 1935: A 50 ton per day mill was installed, and gold, silver and copper production commenced. 1937: A 3-compartment inclined shaft (70 degrees) was sunk west of the original shaft. A 2-compartment winze was developed from the 99 m level to 191 m, with a level at 145 m. Operations ceased in September. 1939: Tashota Nipigon Mines Ltd. was incorporated to retain the property. 1967: The mine was dewatered for Tashota-Nipigon Mines Ltd. and diamond drilling (11 DDH totaling 1219.8 m), underground mapping, sampling, tailings sampling and surface geological mapping was conducted. 1976: Tashota-Nipigon conducted a mag and horizontal loop EM survey over the northern half of the property. 1981: Trenching, linecutting, a geological survey, a mag survey and a Radem VLF survey were undertaken. 1983: Tashota-Nipigon Mines carried out linecutting, and geological, horizontal EM and VLF-EM surveys. 1985: Muscocho Explorations Ltd. conducted a 4500 m diamond drill program and performed minor stripping. 2006: N. Cox and L. Holt carried out a VLF-EM survey. 2015: Opal Energy Corp. announced reclamation plans. 2020: D. Lefort, J. Robert, and A. McLellan carried out prospecting and sampling.

Assessment Work on File

Geology

Province: Superior

Subprovince: Wabigoon

Terrane: Eastern Wabigoon

Belt: Onaman-Tashota

Geological Age: Archean  

Geology Comments

Dec 07, 2005 (B Nelson) - The property is underlain by pillowed, porphyritic and massive mafic metavolcanics which are gradational into rocks termed 'diorite' by Tindale (1967). To the north the metavolcanics are overlain by Algoma type oxide and sulphide facies iron formation. The iron formation extends the full length of the property, at least 600 m, and is a maximum of 25 m thick where not thickened by deformation. Most of the rock types are sheared, and fault breccia and chlorite schist are common on the property. The porphyry dykes include quartz, quartz feldspar porphyry and feldspar porphyry. The dykes are highly sheared toward their margins. The iron formation, chloritic horizons in the mafic metavolcanics, and the dioritic unit south of the shaft form excellent marker horizons to trace structural features. The markers serve to delineate minor secondary folds consisting of a syncline plunging 55-60 degrees northwest. Most of the production of the mine has come from the 'A' ore body. The ore zone dips 70 degrees N and in the upper levels rakes at 68 degrees W. The 'B' zone is located 43 m south of the A zone and has no surface expression. Mineralization included material similar to the A zone. The 'C' zone surface outcrop lies 60 m south of the main shaft. The 'D' zone is projected to surface in the vicinity of the inclined raise. It was thought by Moorehouse to represent the faulted extension of the A zone. The 'E' zone consists of irregular branching pods of mineralization occurring in greenstones near a contact with relatively unaltered porphyry. The localizing structure is probably a fold nose. The 'G' zone occurs at the west end of the 60 m level where a series of lenses of quartz and quartz with po occur over a length of 45 m. The West Zone consists of sheared mafic metavolcanics. The zone is represented by a strongly folaited chlorite-biotite zone hosting a quartz vein.

Lithology

Lithology Comments

Dec 07, 2005 (B Nelson) - OFR 5630 describes the host rock simply as 'greenstone'. No attempt is made to further classify the lithology, although it may in fact be basalt. Muscocho have defined the (cherty) iron formation to be the 'hanging wall.' Primary oxide and sulphide iron formation averaging 9-14 m thick is present in diamond drilling. Chert-chlorite beds, chlorite-garnet-magnetite beds and siltstone or magnetite chert-occur. Py occurs within a matrix of coarser po. Cp is also present. Oxide and sulphide facies iron formation alternate in places. The iron formation has been tightly folded and displays a 55-65 degree NW plunge. Matthews has identified 4 separate iron formation units within the larger 'iron formation'.

Mineralization

Mineralization Comments

Dec 07, 2005 (B Nelson) - All the gold observed in hand specimen and in polished section is found in quartz. The grain size is fine, ranging from 0.01 to 0.1 mm. Although a few minute grains of gold are found entirely surrounded by quartz, most of the gold is in physical contact with po. The position of the gold in relation to its surroundings suggest that it is a late stage mineral occupying minute fissures in the quartz and interstices between quartz and po. Small grains of bismuth were noted in polished section. They occur in quartz in quartz and within the sulphides. Bismuth is thought to be part of an earlier stage of mineralization. The total sulphide content in the zone is typically 2% and up. Biotite is closely associated with gold mineralization. The Northern Miner (Oct. 14, 1985) reported the following results from the G zone: The two deepest holes on the zone to date were drilled 50 feet apart and both intersected the gold bearing structure at a vertical depth of 285 feet. They returned assays of 0.37 oz/ton Au over 5 feet and 0.26 oz/ton Au over 4.5 feet respectively.

Alteration Comments

Dec 07, 2005 (B Nelson) - Alteration minerals are commonly epidote and biotite, particularly noticeable in pillow selvages and fractures.

Mineral Record Details

Site Visit Information

Date: Jan 28, 1997

Geologist: B Nelson

Notes: The Beardmore-Geraldton Economic Geologist visited the site August 14, 1985 and October 23, 1985.

References

Map - Tashota-Onaman River area, District of Thunder Bay, Ontario

Publication Number: ARM34G Scale: 1:126,720    Date: 1998

Author: Gledhill T.L.

Publisher Name: Ontario Dept. of Mines

Location:

Mono - Gold occurrences, prospects, and deposits of the Beardmore-Geraldton area, districts of Thunder Bay and Cochrane

Publication Number: OFR5630 Page: 561-573  Date: 1986

Author: Mason J.K., White G.D.

Publisher Name: Ontario Geological Survey

Location:

Map - Kowkash-Ogoki area, District of Thunder Bay, Ontario

Publication Number: ARM40F Scale: 1:126,720    Date: 1998

Author: Kindle L.F.

Publisher Name: Ontario Dept. of Mines

Location:

MonoMap - Geology of the northern Onaman Lake area, District of Thunder Bay

Publication Number: R208 Date: 1981

Author: Thurston P.C.

Publisher Name: Ontario Geological Survey

Location:

Map - Tashota-Geraldton sheet, geological compilation series, Thunder Bay and Cochrane districts

Publication Number: M2102 Date: 1997

Author: Pye E.G., Harris F.R., Fenwick K.G., Baillie J.

Publisher Name: Ontario Dept. of Mines

Location:

File - Resident Geologist Mineral Deposit Files

Publication Number: Min Dep Date:

Author:

Publisher Name:

Location: Thunder Bay RGP

Map - Onaman Lake, Thunder Bay District

Publication Number: M2411 Scale: 1:31,680    Date: 1979

Author: Thurston P.C.

Publisher Name: Ontario Geological Survey

Location:

Part - Geology of the south Onaman area

Publication Number: ARV47-08 Date: 1998

Author: Moorhouse W.W.

Publisher Name: Ontario Dept. of Mines

Location:

Part - Kowkash-Ogoki area, District of Thunder Bay

Publication Number: ARV40-04.002 Page: 55-104  Date: 1998

Author: Kindle L.F.

Publisher Name: Ontario Dept. of Mines

Location:

Part - Tashota-Onaman gold area (District of Thunder Bay)

Publication Number: ARV34-06.003 Date: 1998

Author: Gledhill T.L.

Publisher Name: Ontario Dept. of Mines

Location:

Book - CIMM TRANS., VOL 39, MECHANICS OF STRUCTURE AT TASHOTA GOLDFIELDS MINE.

Publication Number: Trans. Date: 1936

Author: Flaherty, G.F.

Publisher Name:

Location: Thunder Bay RGP

Article - 1979 report of North Central Regional Geologist

Publication Number: MP091.004 Page: 40  Date: 1997

Author: Fenwick K.G., Larsen C.R., Scott J.F., Mason J.K., Schnieders B.R.

Publisher Name: Ontario Geological Survey

Location:

Folio - Coughlan Lake area, District of Thunder Bay

Publication Number: GDIF026 Date: 1997

Author: Thunder Bay RGO

Publisher Name: Ontario Geological Survey

Location:

Report an Error

We are continuously updating our assessment file / technical report information. If you notice errors in the data, please contact us.

Terms of Use

Please review our Terms of Use agreement for this data product.

Ministry Contact Information

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