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Porcupine-Timmins District (Hollinger, McIntyre, Dome, Pamour, Hallnor, Aunor, Hoyle Pond, Delnite, Bell Creek)
Ontario, Canada
Main commodities: Au

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The Timmins-Porcupine District lies within the Abitibi greenstone belt and has been the most productive gold field in North America having yielded more than 1930 t (62 Moz) of gold from mines such as Hollinger-McIntyre, Dome, Pamour, Hallnor, Hoyle, Hoyle Pond and more recently Bell Creek. Virtually all of the mineralisation has come from quartz-carbonate lode systems hosted by greenshist facies metamorphics and are found in a corridor up to 10 km wide, parallel and to the north of the major regional Porcupine-Destor Fault (#Location: Dome - 48° 27' 46"N, 81° 14' 27"W; Hoyle Pond - 48° 33' 2"N, 81° 6' 27"W; Pamour - 48° 31' 26"N, 81° 6' 33"W).

The rocks within this corridor comprise the younger Group conglomerate, greywacke and slates above a 2679±2 Ma angular unconformity seperating them from the greater than 2698±4 Ma Keewatin Series. The Keewatin is sub-divided into the lower 4500 m thick Dolero Group comprising a lower suite of mainly basaltic and andesitic flows and an upper succession of dacitic flows and dacite-rhyolite pyroclastics with stacked Algoma type iron formations which form a prominent marker unit. These are overlain by the 4000 m thick Tisdale group with a basal section of ultramafic volcanics and basaltic komatiites, and an upper variolitic tholeiitic basalt and then calc-alkaline dacitic volcaniclastics. Most of the gold in the district has been won from the Tisdale Group. The sequence is intruded by volumetrically minor 2688±2 Ma porphyritic felsic stocks emplaced after tilting of the volcanics but prior to the Timiskaming unconformity. The largest deposits of the district (Hollinger-McIntyre-Coniaurum and Dome) show a spatial relationship to these stocks and are enveloped by an extensive zone of carbonate alteration. Although some gold occurs within the stocks, most is in the intruded basalts near the contact with individual stocks.

Gold mineralisation appears to be multiphase, represented by the following: i). Auriferous pyrite in clasts from carbonaceous argillites of the Tisdale Group and sulphidised iron formations of the Dolero Group are found in the basal Timiskaming Group, suggesting an early phase exists, ii). the felsic stocks and adjacent basalts are altered and pervasively mineralised with Cu-Au-Mo, iii). planar, sheeted and en echelon auriferous quartz-ankerite veins and mineralised shear and fault zones cut the Timiskaming Series as well as the Keewatin and porphyries. The third style is by far the most economically significant phase.

Mineralisation at the Dome mine is associated with both the felsic stocks and with the unconformity between the Keewatin and Timiskaming Series. The unconformity defines an asymmetric syncline, plunging shallowly to the east and overlies steeply north dipping volcanics. This structure is truncated to the south by the highly strained and altered Dome Fault which parallels the Destor-Porcupine Fault zone 2 km to the south. The volcanics are intruded by the porphyritic stocks which are in turn cut by the unconformity. The ore at Dome is spread over an area of 2.7x1.2 km and to a depth of 1.6 km and occurs in a number of different forms, predominantly in the volcanics and sediments and to a much lesser degree the porphyries. Vein type ore is present as either concordant quartz-ankerite following interflow sediments, or as discordant quartz-tourmaline or quartz-fuchsite veins, and as arrays and stockworks of extensional veins locally overprinting concordant veins. The laminated veins are restricted to the volcanic suites, while the discordant veins and arrays are found in all units. Disseminated sulphide mineralisation comprises zones of 2-10% pyrite and pyrrhotite with or without associated extensional vein arrays and stockworks. Gold is found in the veins and the disseminated sulphide accumulations, fringed by carbonate-sericite alteration.

The Dome mine was most recently owned and operated by Goldcorp. Historically it was operated by Dome Mines and then Placer Dome. Production from the mine during 2000 reached a cumulative total of 14 Moz (435 t) Au. Proved & probable reserves at the end of that year were 48 t, sufficient for a further 4 years of operation, comprising 27.71 Mt @ 1.7 g/t Au, with additional measured, indicated and inferred mineralisation of 52.87 Mt @ 2.12 g/t Au. During 2000, 4.234 Mt of ore were milled at an average head grade of 2.5 g/t Au for 9.76 t Au. Some 20% of the production was from underground with the balance from an open pit with a waste:ore stripping ratio of 4.3:1. Metallurgical recovery was 92.3%. Dome Underground mine ceased operations in 2017.

The Hoyle Pond mine of Goldcorp is a high grade, narrow vein underground mine, which in 2000 milled 0.462 Mt at an average head grade of 11.27 g/t Au for 4.37 t (0.140 Moz) Au. After commencing operations in 1985, the remaining reserves at Hoyle Pond at the end of 2000 were 0.93 Mt @ 12.3 g/t Au. These were supplemented by an open-pittable reserve of 14.17 mt @ 1.7 g/t Au on the adjacent Pamour-1 leases which the company recently aquired. As of 2022, ~60% of the gold production from Gold Corp. mines in the district comes from the Hoyle Pond underground mine, where mechanized cut and fill and longhole mining methods are used to extract the ore. The remaining ore comes from the Hollinger Open Pit mine.

The McIntyre-Hollinger, also known as the Schumacher Mine, has been in continuous production since the early 1900's and had produced over 902 t (29 Moz) of gold to 1985.   Mineralisation is present as a series of quartz-ankerite veins, stockworks and sinuous lodes and stringers crosscutting the host rocks.   These veins outcrop on the Hollinger leases and plunge north-easterly through the McIntyre Mine.   They branch at the western end of the Pearl Lake Porphyry (a quartz-albite-sericite schist) and continue east in mafic hosts on both margins of the approximately east-west elongated porphyry body.   Individual veins often parallel foliation and fold hinges, while the system as a whole follows the dominant NE trending fold axes.   In addition, at McIntyre, there is disseminated auriferous pyrite and quartz vein and stringer mineralisation within carbonaceous and graphitic material.

The Bell Creek mine is located in the southwest portion of Hoyle Township in the Porcupine Mining Division, ~14 km NE of Timmins and 6 km north of Porcupine. It is hosted by Archaean carbonate altered, greenschist facies, metavolcanic and clastic metasedimentary rocks of the 2710 to 2704 Ma Tisdale and 2690 to 2685 Ma Porcupine assemblages which generally strike east-west to WNW, with steep southerly dips. The metavolcanic portion of the stratigraphy represents the lower portion of the Tisdale Assemblage. The clastic metasedimentary rocks belong to the Porcupine assemblage.
  The Tisdale ultramafic metavolcanic rocks comprise massive, spinifex, and poly-sutured textured flows and derived schists. Ultramafic schist is characterized by a fissile habit, abundant talc, and magnesium-rich chlorite and carbonate (Berger, 1998). In Hoyle Township area the lower ultramafic metavolcanic rocks are basaltic komatiite (Berger, 1998; Pressacco, 1999). Kent (1990) describes the ultramafic rock sequence at Bell Creek as 100 to 200 m thick lens-shaped units with intense local ankerite-fuchsite alteration. These Tisdale mafic metavolcanic rocks include massive, pillowed and breccia flow textures. Several thin interflow sedimentary horizons are intercalated within the mafic sequence (Kent 1990). Flow units occur with a flow top breccia which has a gradational contact into a pillowed base. Abundant leucoxene is associated with the iron-rich tholeiitic basalts of the lower Tisdale Assemblage and has been used to distinguish it from Mg-rich basalts (leucoxene absent) in this formation.
  The Porcupine Assemblage metasedimentary rock units compris wacke, siltstone, mudstone, graphitic and pyritic mudstone (Jackson and Fyon, 1991; Berger, 1998). Chlorite and sericite are the most common alteration minerals in the matrix, whereas biotite is absent in most metasedimentary rocks in Hoyle Township. Green, grey and dark grey mudstone is found throughout the Hoyle assemblage overlying wacke. Graphite and amorphous carbon are the major opaque minerals but comprise <5% of the rock. Graphitic and pyritic mudstone are distinctive, occurring along, or within, 400 m of the contacts with mafic metavolcanic rocks of the Tisdale Assemblage. Pyrite comprises from 1 to 30% of the graphitic mudstone and occurs in two forms, as nodular pyrite balls that are 1 to 20 mm in diameter, and as disseminated to massive laminated or bedded layers 1 to 10 mm thick (Berger, 1998). North-south trending swarm of dolerite dykes containing 15% magnetite intrude the Archaean rocks, and are correlated with the Palaeoproterozoic Matachewan swarm.
  Gold mineralisation occurs in a series of steeply south dipping, sheet like, shear hosted mineralised zones. Of these, the bulk of the mineralization lies within the North A, North A2, North B and North B2 zones. The North A zone has been the major source of production. Mineralization and geological setting of these zones are similar. The North A Zone comprises a marker quartz vein that varies from 0.1 to 2 m in thickness with an associated alteration halo. Adjacent to the quartz marker vein is a grey to buff colored altered zone containing 5% to 15% pyrite and pyrrhotite, with accessory chalcopyrite and arsenopyrite. Up to 30% of the gold in the North A Zone occurs within the alteration halo, in discrete sulphide zones and in vein-brecciated wall rock zones that extend up to 5 m from the margin of the core vein (Kent, 1990).
  Current Ore Reserves and Mineral Resources at Bell Creek include (Pan America Silver NI 43-101 Technical Report dated June 2021):
    Proved + Probable Ore Reserves - 4.97 Mt @ 3.0 g/t Au for 14.92 tonnes of contained gold;
    Measured + Indicated Mineral Resources - 5.376 Mt @ 3.0 g/t Au for 16.10 tonnes of contained gold;
    Inferred Mineral Resources - 4.727 Mt @ 3.2 g/t Au for 15.20 tonnes of contained gold.
NOTE: Resources include Reserves. 3.0

The most recent source geological information used to prepare this decription was dated: 2022.     Record last updated: 4/12/2022
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd.   Unauthorised copying, reproduction, storage or dissemination prohibited.

Hoyle Pond



  References & Additional Information
   Selected References:
Bateman R and Bierlein F P,  2007 - On Kalgoorlie (Australia), Timmins-Porcupine (Canada), and factors in intense gold mineralisation: in    Ore Geology Reviews   v32 pp 187-206
Bateman R, Ayer J A and Dube B,  2008 - The Timmins-Porcupine Gold Camp, Ontario: Anatomy of an Archean Greenstone Belt and Ontogeny of Gold Mineralization: in    Econ. Geol.   v103 pp 1285-1308
Burrows D R, Spooner E T C, Wood P C, Jemielita R A  1993 - Structural controls on formation of the Hollinger-McIntyre Au quartz vein system in the Hollinger shear zone, Timmins, southern Abitibi Greenstone belt, Ontario: in    Econ. Geol.   v88 pp 1643-1663
Dinel E, Fowler A D, Ayer J, Still A, Tylee K and Barr E,  2008 - Lithogeochemical and Stratigraphic Controls on Gold Mineralization within the Metavolcanic Rocks of the Hoyle Pond Mine, Timmins, Ontario: in    Econ. Geol.   v103 pp 1341-1363
Gray M D, Hutchinson R W  2001 - New evidence for multiple periods of Gold emplacement in the Porcupine mining district, Timmins area, Canada: in    Econ. Geol.   v96 pp 453-475
Haugaard, R., Justina, F., Roots, E., Cheraghi, S., Vayavur, R., Hill, G., Snyder, D., Ayer, J., Naghizadeh, M. and Smith, R.,  2021 - Crustal-Scale Geology and Fault Geometry Along the Gold-Endowed Matheson Transect of the Abitibi Greenstone Belt: in    Econ. Geol.   v.116, pp. 1053-1072.
Moritz R P, Crocket J H  1991 - Hydrothermal wall-rock alteration and formation of the gold-bearing quartz-fuchsite vein at the Dome mine, Timmins area, Ontario, Canada: in    Econ. Geol.   v86 pp 620-643
Rogers D S   1982 - Diamond drilling as an aid in ore definition at the Dome mine: in    CIM Bull.   v75 no. 842 pp 98-104
Schneider D A, Bachtel J and Schmitt A K,  2012 - Zircon Alteration in Wall Rock of Pamour and Hoyle Pond Au Deposits, Abitibi Greenstone Belt: Constraints on Timescales of Fluid Flow from Depth-Profiling Techniques : in    Econ. Geol.   v.107 pp. 1043-1072
Smith T J, Cloke P L, Kesler S E  1984 - Geochemistry of fluid inclusions from the McIntyre-Hollinger Gold deposit, Timmins, Ontario, Canada: in    Econ. Geol.   v79 pp 1265-1285
Snyder D B, Bleeker W, Reed L E, Ayer J A, Houlé M G and Bateman R,  2008 - Tectonic and Metallogenic Implications of the Regional Seismic Profiles in the Timmins Mining Camp: in    Econ. Geol.   v103 pp 1135-1150
Walsh J F, Kesler S E, Duff D, Cloke P L  1988 - Fluid inclusion geochemistry of high-grade, vein-hosted Gold ore at the Pamour mine, Porcupine camp, Ontario: in    Econ. Geol.   v83 pp 1347-1367

Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge.   It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published.   While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants:   i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and   ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.

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