Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI42A09SE00015

Record: MDI42A09SE00015

General

Commodities

Primary Commodities: Copper, Zinc

Secondary Commodities: Gold, Nickel, Cobalt, Silver

Location

Township or Area: Munro

Latitude: 48° 35' 57.26"    Longitude: -80° 12' 39.93"

UTM Zone: 17    Easting: 558164   Northing: 5383207    UTM Datum: NAD83

Resident Geologist District: Kirkland Lake

NTS Grid: 42A09SE

Point Location Description: A shaft 6.84 km north and 4.64 km east of the southwest corner of Munro Township.

Location Method: AMIS Site Visit

Access Description: The Potter Mine shaft is in the south half of lot 7, concession V, Munro Township, approximately 20 km east northeast of Matheson. Access is via an improved sand and gravel road accessible from highway 101 near the southeast corner of Munro Township.

Exploration History

Circa 1930: 35 ft deep shaft sunk on faulted gabbro and rhyolite contact. 1949: Canadian Johns-Manville Ltd: mag. survey, 3 DDH's (594 ft). 1952: R. S. Potter: 10 DDH's (2,423 ft) along 500 ft strike length; Hole #2 intersected sulphides. 1953-55: Centre Hill Mines Ltd: mag. survey. 1956: mag., geol. surveys; 40,000 ft DD along 1,350 strike length. 1957: Three-comp. shaft sunk to 408 ft; x-cut est. at 350 level; drifting (42 ft) and x-cutting (97 ft) completed on main lens; 2 surface DDH's (800 ft); 100 tons material hoisted. 1958: 250 lb u/g dump sample sent for analysis. 1959: EM survey; 4 surface DDH's (1,000 ft) along MMZ. 1964: shaft dewatered and deepened to 634 level; 476 and 602 levels est.; 6 u/g DDH's (534 ft); drifting (1,032 ft), x-cutting (264 ft). 1965: shaft deepened to 630 ft level; drifting (655 ft), x-cutting (252 ft); 92 DDH's (22,373 ft); mineralogical study on ore samples. 1966: MUNRO COPPER MINES LTD: headframe heightened to 100 ft; shaft deepened to 970 ft; levels est. at 200, 725, and 850; on site mill and concentrator nears completion; drifting (1,208ft), x-cutting (433ft), raising (898ft); 36 DDH's (2,049ft). 1967: drifting (3,842ft), x-cutting (96ft), raising (3,466ft); 117,512 tons of ore milled. (1968): company into receivership; renamed Potter Mine. 1969: Harrison Drill, and Expl. Co. Ltd: drifting (2,162ft), x-cutting (300ft), raising (1,119ft); 11 u/g DDH's (2,369ft); 101,802 tons material hoisted; 101,225 tons milled. (1970): shaft deepened to 1,272ft; levels est. at 976, 1,102, and 1,228; drifting (4,453ft), x-cutting (97ft), raising (2,045ft); 135 u/g DDH's (20,050ft); 63,767 tons hoisted, 87,095 tons milled. 1971: milling at 650 tons/day; u/g expl. and dev. at 976 and 1,102 levels. 1972: u/g operations and milling ceased; mine allowed to flood; surface openings sealed with concrete bulkheads. 1975: mill equip. sold to Noranda Ltd. In 1996 Millstream Mines Ltd. completed line cutting and grid establishment, ground geophysical surveys consisting of a ground magnetometer survey, a horizontal loop electromagnetic (HLEM) and very low frequency VLF-EM surveys along with nine (9) exploration diamond drill holes totaling 1606 meters were completed. In 1997-1998, further line cutting and grid establishment, an Induced Polarization (Real Section I.P.) geophysical surveys were carried out. Nineteen exploration (19) diamond drill holes were also completed totaling 9,688 meters that helped to confirm the interpretation of the down dip continuation of the Potter Mine mineralization. In 1999-2000 a further ten (10) exploration diamond drill holes totaling 5899 meters were completed. In addition a colour air photo survey was conducted over the property with ground fixed surveyed control points (latitude, longitude, and elevation) in order to tie the old mine imperial grid, the surface metric grid, and all drill hole collars into a common UTM coordinate system for the property. Down hole geophysical 3D Bore Hole Transient Electromagnetic (3D BHTEM) surveys were also conducted on selected diamond drill holes to aid in identifying any off hole conductors. Geological and geochemical surveys were also conducted during this period. 2006-2008 Millstream Mines - diamond drill program was completed on the Potter mine property with 33 holes totaling 20,453 meters.

Assessment Work on File

Geology

Province: Superior

Subprovince: Abitibi

Terrane: Wawa-Abitibi

Belt: Abitibi

Tectonic Assemblage: Stoughton-Roquemaure

Geological Age: Mesoarchean  

Metamorphism Grade: Greenschist

Geology Comments

Dec 07, 2005 (D Guidon) - The Potter Mine Property is located in the eastern part of the Kidd-Munro assemblage of the Abitibi Greenstone Belt. The Kidd-Munro assemblage is a fault-bounded package of ultramafic and mafic volcanic rocks, subvolcanic intrusions and thin felsic and mafic fragmental volcanic units that extends some 130 kilometers westward from Timmins to east of Matheson. Isotopic age determinations indicate these rocks are about 2,715 million years ('Ma') old and are considered to represent deposits of an ancient volcanic arc or back-arc basin that were tectonically accreted, along with older and younger assemblages of similar origins, during the Late Archean orogenic events that resulted in the formation of the Superior Province of the Canadian Shield. The Abitibi greenstone belt is the world's largest, best-preserved greenstone belt, and is also one of the most mineral-rich. The Kidd-Munro sequence hosts a number of mineral deposits, including the world-class Kidd Creek volcanogenic massive sulphide deposit, the Dundonald and Alexo komatiitic nickel deposits and several major lode gold deposits. On the Potter Mine Property, the main rock types recognized include Archean komatiitic and basaltic volcanic rocks, gabbro, peridotite and pyroxenite of intrusive and/or extrusive origin, and mafic fragmental volcanic rocks. These rocks form relatively continuous stratigraphic units that trend west-northwest to east-west across the Property. The sequence is folded about west-northwest trending axes, and is displaced by northwest, north and northeast trending faults. The Archean rocks and structures are cut by Proterozoic mafic dykes of two ages, an older (2,450 Ma), north-striking Biscotasing swarm.

Dec 07, 2005 (R Degagne) - Bedrock volcanic stratigraphy in the mine area strikes southeast, dips steeply north, faces north, and occupies part of the south limb of the McCool Hill Syncline, a regional scale, southeast striking and northwest plunging fold which constitutes the dominant regional scale structure north of the locally southeast striking) Main Branch (Johnstone 1987, Jensen and Langford 1985) of the Porcupine-Destor Fault Zone in the central BRIM area. Intrusive rocks in the mine area in addition to the mafic to ultramafic layered intrusive body include a granitic body located south of the Centre Hill Intrusive Complex and north striking quartz diabase dikes of the (Proterozoic) Matachewan swarm (Heaman 1989). A laterally persistent fault, the Centre Hill Fault (Johnstone 1987), occurs south of the Centre Hill Complex. This fault is oriented parallel to other faults of the Porcupine-Destor Fault system and offsets about 3 km sinestrally the axial surface trace of the McCool Hill Syncline in south central McCool Township (Johnstone 1987). A sinestral sense of offset along this fault is consistent with the sense of drag folding developed marginal to it within the Centre Hill Complex (Johnstone 1987, Satterly 1952). Fe-Cu-Zn sulfide mineralization at the Potter Mine is hosted by rocks immediately stratigraphically overlying (north of) the Centre Hill Complex (Satterly 1952), that part of the Munro Lake Sill (MacRae 1969, Johnstone 1987) which is exposed on Centre Hill in central Munro Township. The Munro Lake Sill is a thick (ranging from about 400 m in thickness at its ends to as much as about 600 m in thickness locally (Johnstone 1987)) ultramafic to mafic layered sill which is interpreted (MacRae 1969, Johnstone 1987) to extend southeast from the Centre Hill area, to swing around the closure of the McCool Hill Syncline in central McCool Township, and to extend northwest through northern Munro Township as far as southwest Warden Township, a distance of about 20 km.

Lithology

Lithology Comments

Dec 07, 2005 (R Degagne) - Geological mapping (Satterly 1952; Pyke et al. 1973; Arndt et al. 1977; Johnstone and Trowell 1985, 1984; Johnstone 1987, 1986; Jensen and Baker 1986; Arndt 1977, 1975; Johnstone and Steele 1989; Vagners 1984; McClenaghan et al. 1988, 1987; Steele 1988) indicates the deposit area to be underlain mainly by variably glacial drift covered weakly metamorphosed (greenschist or lower facies) ultramafic to felsic volcanic and volcaniclastic rocks and a mafic intrusive body (the Centre Hill Complex) of the (Archean) Stoughton-Roquemaure Group. Sulfide mineralization at the Potter Mine is reported to consist of fine grained pyrrhotite, chalcopyrite, sphalerite, pyrite, and minor native silver which occur as multiple shoots within the upper part of a thin (5-25 m thick (Coad 1976)) carbonaceous and carbonatized (calcite) horizon of Mg-tholeiitic basalt fragmental and/or hyaloclastic rocks and a thin (less than 1.5 m thick (Coad 1976)) horizon of dacitic ash (or tuff) immediately overlying (north of) the Centre Hill Complex and immediately underlying intercalated tholeiitic and komatiitic volcanic flows. The fragmental rocks are reported (Coad 1976) to be in sheared but conformable contact with both the underlying uppermost gabbroic phase of the Centre Hill Complex and the overlying tholeiitic and komatiitic volcanic flow rocks. The ore is reported (Coad 1976) to have consisted of both sulfide mineralization within the fragmental breccia matrix (generally near the top of the fragmental unit) and as fine grained finely laminated massive sulfides atop the fragmental horizon and/or within the thin dacitic ash horizon. Coad (1976) described the ore shoots to be narrow bodies (in horizontal cross section ranging from 15-30 m in width and generally averaging about 1 m in thickness) with considerable extent in the third (down dip) dimension.

Mineralization

Mineralization Comments

Dec 07, 2005 (D Guidon) - Most of the sulphide mineralization in the area occurs within the mafic fragmental unit, which generally contains 1 to 5% sulphide minerals, mainly pyrrhotite with some pyrite, and, locally chalcopyrite and sphalerite. These are; however, a great variation in sulphide mineral content. For example, east of the Potter mine, the mafic fragmental unit is poor in sulphides, generally containing 1% or less pyrrhotite. West of the Potter mine, the unit is more heavily mineralized with disseminated and massive sulphides. In the north, the mafic fragmental unit generally contains 1 to 5% sulphides and there are meter-scale pods with 25% or more sulphides. The sulphide minerals, mainly pyrrhotite and pyrite with minor chalcopyrite, occur as disseminations in altered (chloritic, graphitic, silicified) rocks and as massive lenses which commonly have millimeter-scale banding. Graphite is associated with sulphide mineralization and may be present in amounts of 5% to 10% or more. In the graphitic rocks, pyrite and pyrrhotite commonly form framboids, zoned circular to elliptical bodies up to 3 centimeters in diameter. Zones of chlorite alteration and silicification are also closely associated with sulphides, notably in the Potter mine area.

Dec 07, 2005 (R Degagne) - Sulfide mineralization at the Potter Mine is reported to consist of fine grained pyrrhotite, chalcopyrite, sphalerite, pyrite, and minor native silver which occur as multiple shoots within the upper part of a thin (5-25 m thick (Coad 1976)) carbonaceous and carbonatized (calcite) horizon of Mg-tholeiitic basalt fragmental and/or hyaloclastic rocks and a thin (less than 1.5 m thick (Coad 1976)) horizon of dacitic ash (or tuff) immediately overlying (north of) the Centre Hill Complex and immediately underlying intercalated tholeiitic and komatiitic volcanic flows. The ore is reported (Coad 1976) to have consisted of both sulfide mineralization within the fragmental breccia matrix (generally near the top of the fragmental unit) and as fine grained finely laminated massive sulfides atop the fragmental horizon and/or within the thin dacitic ash horizon. Coad (1976) described the ore shoots to be narrow bodies (in horizontal cross section ranging from 15-30 m in width and generally averaging about 1 m in thickness) with considerable extent in the third (down dip) dimension. Where massive sulfides are developed, they are reported to display locally developed weak banding, with several centimetre thick layers of pyrrhotite alternating with 1 centimetre wide layers of chalcopyrite-sphalerite. Often, a local metal zonation is displayed, with individual layers displaying copper-rich bases and zinc-rich tops. Coad (1976) also reported that the deposit as a whole exhibits a metal zonation, with central domains displaying elevated Cu/Zn values. Gangue minerals are reported (Coad 1976) to include tremolite, chlorite, epidote, calcite, and graphite. Chloritic domains coincide with elevated Cu/Zn values. Although no stringer sulfide mineralization is reported, Coad (1976) reported stringer-type ore in the chloritic and copper rich parts of the mine.

Alteration Comments

Dec 07, 2005 (R Degagne) - The mine site was examined by the writer during 1984. The hyaloclastite host rock crops out prominently in the mine area along the northern margin of Centre Hill. It consists of a hard, grey, brown to rusty-weathering medium grained fragmental rock which looks rhyolitic and has been mapped as such (Satterly 1952). The rock examined was clast supported and was composed of moderately well sorted pea-sized angular to subrounded fragments with a recessively-weathering carbonate bearing fine grained matrix. The contacts between this fragmental horizon and the (underlying) tholeiitic gabbro of the Centre Hill Complex and the (overlying) komatiitic and tholeiitic flows were not observed. Coad (1976) presents a convincing case for the replacement and submarine exhalative origin for the Potter Mine sulfide mineralization. The banded nature of the massive sulfides; their often sharp contacts with overlying flow rocks and diffuse, gradational contacts with underlying matrix sulfide mineralization; metal zoning at both the local (i.e. massive sulfide beds displaying copper-rich bases and zinc-rich tops) and deposit (i.e. a copper-rich core zone with zinc-rich marginal areas) scales; the inferred presence of chloritic alteration zones coincident with zones of maximum Cu/Zn ratios; and the reported presence of stringer-type mineralization in the copper-rich areas are all consistent with subaqueous exhalative and associated replacement sulfide mineralization.

Mineral Record Details

Mineral Zones - Size and Shape

Rank: 1       Structure Type: Shear

Site Visit Information

Date: Jan 30, 1997

Geologist: R Degagne

Notes: The mine site was visited in 1984 by A. C. Bath (OFR 5735, V.1, p.272). Coad (1976) presents a convincing case for the replacement and submarine exhalative origin for the Potter Mine sulfide mineralization. The banded nature of the massive sulfides; their often sharp contacts with overlying flow rocks and diffuse, gradational contacts with underlying matrix sulfide mineralization; metal zoning at both the local (i.e. massive sulfide beds displaying copper-rich bases and zinc-rich tops) and deposit (i.e. a copper-rich core zone with zinc-rich marginal areas) scales; the inferred presence of chloritic alteration zones coincident with zones of maximum Cu/Zn ratios; and the reported presence of stringer-type mineralization in the copper-rich areas are all consistent with subaqueous exhalative and associated replacement sulfide mineralization. The Potter Mine sulfide mineralization is postulated by Coad (1976) to have been deposited within and atop porous hyaloclastic and/or fragmental volcanic rocks shortly after their deposition by channelled hydrothermal fluids which were circulating in response to the heat released by the cooling Centre Hill Complex. The copper and zinc are believed to have been leached by these fluids from the uppermost gabbroic part of the Centre Hill Complex; Coad demonstrates that this hypothesis is consistent with the alteration assemblage displayed by the gabbro as well as its metal content. Sulfide mineralization similar to that at the Potter Mine may occur in an analogous stratigraphic setting elsewhere along the Munro Lake Sill. The Potterdoal deposit, in northern Munro Township, may be an example of such mineralization which has been mobilized along a fault.

References

File - Resident Geologist file KL-4638

Publication Number: Date:

Author:

Publisher Name:

Location: Kirkland Lake RGP office

Map - Quaternary geology of Matheson area, Cochrane District

Publication Number: P2735 Scale: 1:50,000    Date: 1985

Author: Vagners U.J.

Publisher Name: Ontario Geological Survey

Location:

Map - Township of Munro, District of Cochrane, Ontario

Publication Number: M1951-05 Date: 1997

Author: Satterly J., Hogg N.

Publisher Name: Ontario Dept. of Mines

Location:

Map - Geophysical/geochemical series, Matheson-Black River area, Munro Township, airborne electromagnetic survey, total intensity magnetic survey, District of Cochrane

Publication Number: M80586 Scale: 1:20,000    Date: 1984

Author: Questor Surveys Ltd.

Publisher Name: Ontario Geological Survey

Location:

Part - Geology of Munro Township

Publication Number: ARV60-08 Page: 19-21  Date: 1997

Author: Satterly J.

Publisher Name: Ontario Dept. of Mines

Location:

Map - Geological series, bedrock samples from the sonic drilling program 1987, Matheson area, District of Cochrane

Publication Number: P3114 Scale: 1:100,000    Date: 1989

Author: Johnstone R.M., Sutcliffe R.H., Steele K.G., Baker C.L., McClenaghan M.B.

Publisher Name: Ontario Geological Survey

Location:

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

Publication Number: MDC012 Page: 124-125  Date: 1969

Author: Shklanka R.

Publisher Name: Ontario Dept. of Mines

Location:

Folio - Munro Township, District of Cochrane

Publication Number: GDIF361 Date: 1997

Author: Kirkland Lake RGO

Publisher Name: Ontario Geological Survey

Location:

Map - Black River-Matheson Area

Publication Number: OFM0013 Scale: 1:15,840    Date: 1985

Author: Johnstone R.M., Trowell N.F.

Publisher Name:

Location:

Map - Geological series, Precambrian geology of the Magusi River area, Cochrane and Timiskaming districts

Publication Number: P2434 Scale: 1:63,360    Date: 1982

Author: Jensen L.S.

Publisher Name: Ontario Geological Survey

Location:

Mono - Mineral occurrences, deposits, and mines of the Black River-Matheson area

Publication Number: OFR5735 Page: 266-278  Date: 1990

Author: Bath A.C.

Publisher Name: Ontario Geological Survey

Location:

File - Res/Reg Property Visit KL #153

Publication Number: PV-153 Date: 1901

Author:

Publisher Name:

Location: Kirkland Lake RGP office

Map - Geological series, Precambrian geology of the Magusi River area, Cochrane and Timiskaming districts

Publication Number: P2434 Scale: 1:63,360    Date: 1982

Author: Jensen L.S.

Publisher Name: Ontario Geological Survey

Location:

Map - Geological Compilation: Beatty and Munro Townships

Publication Number: P3395 Scale: 1:20,000    Date: 1999

Author: Barrie C.T.

Publisher Name: Ontario Geological Survey

Location:

Map - Quaternary Geology, Matheson Area

Publication Number: M2652 Scale: 1:50,000    Date: 2000

Author: Vagners U.J.

Publisher Name: Ontario Geological Survey

Location:

Map - Geology of Munro Township

Publication Number: OFM0159 Scale: 1:15,840    Date: 1991

Author: Johnstone R.M.

Publisher Name: Ontario Geological Survey

Location:

Journal - Komatiitic and Iron-rich Tholeiitic Lavas of Munro Township, Northeast Ontario; Journal of Petrology, vol. 18, no. 2

Publication Number: JourPet V18 Page: 319-369  Date: 1977

Author: Arndt, N. T., Naldrett, A.J., and Pyke, D.R.

Publisher Name: Journal of Petrology

Location:

Thesis - The Potter Mine

Publication Number: MSc Thesis Date: 1976

Author: Coad, P. R.

Publisher Name: University of Toronto

Location: Kirkland Lake RGP Office

Book - Geology and petrogenesis of the Archean Abitibi belt in the Kirkland Lake area, Ontario

Publication Number: MP123 Date: 1985

Author: Jensen L.S., Langford F.F.

Publisher Name: Ontario Geological Survey

Location:

Article - Precambrian geology of the Black River-Matheson (BRIM) area, District of Cochrane

Publication Number: MP126.056S Date: 1997

Author: Johnstone R.M., Trowell N.F.

Publisher Name: Ontario Geological Survey

Location:

Mono - Annual report on mineral industry operations in Ontario during calendar year 1970

Publication Number: ARV80 Date: 1998

Author: Matten E.E.

Publisher Name: Ontario Dept. of Mines and Northern Affairs

Location:

Book - Mineralogical investigation of samples of a copper-zinc ore from the Centre Hill Mine, Munro Tp. Ontario

Publication Number: IR 65-103 Date: 1965

Author: Petruk, W.

Publisher Name: Energy, Mines and Resources Canada

Location:

Journal - Archean Ultramafic Flows in Munro Township, Ontario; GSA Bulletin, vol. 84, no. 3

Publication Number: GSA Bull V84 Page: 955-978  Date: 1973

Author: Pyke, D.R., Naldredd, A.J., and Eckstrand, O.R.

Publisher Name: Geological Society of America

Location:

Mono - Annual report on mining operations in Ontario during calendar year 1969

Publication Number: ARV79 Date: 1998

Author: Riddell G.S.

Publisher Name: Ontario Dept. of Mines and Northern Affairs

Location:

MonoMap - The geology of the northwestern Black River-Matheson area, District of Cochrane

Publication Number: OFR5785 Date: 1991

Author: Johnstone R.M.

Publisher Name: Ontario Geological Survey

Location:

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