Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI42L11NE00003

Record: MDI42L11NE00003

General

Commodities

Primary Commodities: Iron

Location

Township or Area: Tennant Lake Area

Latitude: 50° 40' 36.04"    Longitude: -87° 5' 57.07"

UTM Zone: 16    Easting: 492992   Northing: 5613876    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 42L11NE

Point Location Description: collar of DDH WM-2

Location Method: Based on Assessment

Exploration History

1954-55: Lake Superior Iron Limited – airborne and dip needle surveys. 1955: Lake Superior Iron Limited – DD-40. 1957-61: Anaconda Co. Ltd. – DD

Assessment Work on File

Geology

Province: Superior

Subprovince: English River

Terrane: English River Basins

Belt: Melchett Lake

Geological Age: Archean  

Lithology

Lithology Comments

Aug 18, 2014 (A Wilson) - The iron formation is of the oxide facies of the Algoma type. Bands of magnetite and quartz with thicknesses ranging from one eighth inch to almost a foot alternate with bands of quartzite and greywacke. Accessory minerals include amphibole, pyroxene, feldspar and chlorite. Minor amounts of specular hematite are found in the Briarcliffe Lake area, but it is rare east of that point. The iron formation is cut by muscovite-biotite-quartz-feldspar pegmatites. Two bands of iron formation, one of low grade and not economically important, and a younger, more continuous band are found on the property. They strike east and dip steeply north. The two bands are separated by about 2,000 feet of metagreywacke (biotite-quartz-feldspar schist). The younger band is composed of a basal, low-grade unit 100-400 feet thick and an upper, higher-grade unit which forms the economically important material. The combined thickness of the two bands is a maximum of 500 feet in the vicinity of the Briarcliffe Lake zone. The bands dip vertically to steeply north and are isoclinally folded about an east-trending axis to form an anticline plunging up to 60°E in the western part of the fold and flattening to 5-20°N at the eastern end. The axial plane of the main fold is vertical in the western part of the area, but flattens toward the east where dips as low as 20 degrees are recorded. The flattening of the fold axis to the east caused the nose of the fold to be downfaulted to its present position at Two Mile Lake. The northern limb of this major fold has a Z-shaped drag fold at Briarcliffe Lake.

Mineralization

Mineralization Comments

Aug 18, 2014 (A Wilson) - Anaconda announced in 1966 that the deposits contained 335 million tons of open pit ore "averaging approximately 26.2 percent acid soluble iron". Pellets were to be produced by mining to a 400-foot depth with grinding to minus 150-200 mesh followed by magnetic concentration. The pellets will have a dry analysis of 67 percent iron with 2 percent silica.

Mineral Record Details

References

Map - Compilation series, Ogoki Lake sheet, Thunder Bay and Cochrane districts

Publication Number: P0274 Scale: 1:126,720    Date: 1997

Author: Stott G.M., McConnell C.D., Mason J.K.

Publisher Name: Ontario Geological Survey

Location:

Mono - Operation Fort Hope

Publication Number: MP042 Page: 22, 51-54  Date: 1970

Author: Thurston P.C., Carter M.W.

Publisher Name: Ontario Dept. of Mines and Northern Affairs

Location:

Mono - Iron deposits of Ontario

Publication Number: MDC011 Page: 445  Date: 1968

Author: Shklanka R.

Publisher Name: Ontario Dept. of Mines

Location:

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Ministry Contact Information

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