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LaRonde - Penna
Quebec, Canada
Main commodities: Au Zn Cu

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The Doyon, Bousquet #1 & 2, Dumagami and the LaRonde-Penna mines are located within the Archaean (2703±2 Ma) Blake River Group in the eastern part of the Abitibi Greenstone Belt, 40 km east of Rouyn-Noranda in Quebec, Canada.

All are developed within the same volcanic rocks and share a number of geological characteristics. These and a series of other smaller occurrences (including Mic-Mac and Mouska) are found over a strike length of 6.5 km to the north of the Larder Lake-Cadillac Fault zone in a narrow attenuated strip of volcanics that are the eastern extension of the Blake River Group that host the auriferous massive sulphide base metal deposits of the Noranda district to the west. These volcanics have faulted contacts with the Kewagama Group greywackes and mudstones to the north and the Cadillac Group greywacke and conglomerate to the south. The mineralised interval is found within the east-west striking, steeply south-dipping southern portion of the belt of Blake River Group which comprise roughly comparable amounts of felsic volcaniclastics and mafic flows and volcaniclastics. To the west they are intruded by the Mooshla Complex of gabbro, quartz-diorite, porphyritic tonalite and trondhjemite phases.

In the southern part of the volcanic belt, the rocks have been overprinted by the strong penetrative S2 foliation of the Dumagami high strain zone. This foliation dips steeply to the south with a steep west plunging stretching lineation. The deformation increases until it becomes a laterally continuous band of quartz-sericite and chlorite-carbonate schist derived from felsic and mafic protoliths respectively.

The mineralisation is of three main types, all of which are sulphide rich:

i). Massive sulphide, VHMS lenses as at LaRonde-Penna, Bousquet #2 - Dumagami and Bousquet #1 and the smaller Westwood, Ellison and Warrenmac deposits.   These lenses are stacked at different stratigraphic intervals within the Bousquet Formation, with the uppermost lenses to the east. All plunge steeply to the to the west and represent both primary elongation along regularly spaced syn-volcanic faults, and stretching-flattening during the main deformation event. Volcanic units, hydrothermal alteration and metal zonation folows the same geometric distribution.  The ore lenses are associated with discordant and subconcordant alteration zones composed of vartiable amounts of aluminosilicates (including kyanite, andalusite, pyrophyllite and staurolite), garnet (spessartine, almandine), biotite, carbonates, chlorite, epidote, phengite, quartz, rytile, sericite and titanite.
    The Dumagami ore deposit comprises a series of massive pyrite lenses with strike lengths of a few tens of metres, thickness of a few metres, but down plunge extents of around 800 m.   Each of these shoots is surrounded by two concentric alteration assemblages, namely  a). an inner andalusite bearing zone corresponding to a premetamorphic advanced argillic alteration and  b). an outer micaceous, micaceous phyllonite and phyllonitic breccia that was metamorphosed from a sericitic protolith.

ii). Intrusion-related Au-Cu vein systems as at Doyon, composed of sulphide rich (>25% sulphides up to 80%) and quartz-sulphide veins and veinlets, (usually <20 cm thick) separated by disseminated pyrite.  These vein systems are hosted by the low strain porphyritic tonalite of the Mooshla sub-volcanic intrusion and highly altered schistose ± mafic volcanic rocks in the upper Bousquet Formation. They form slightly discordant and stucturally transposed stockworks accompanied by alteration assemblages similar to those accompanying the VHMS lenses; and

iii). Greenstone hosted quartz-carbonate Au-Cu veins at Mouska, Mic Mac and Mooshla occurring as sulphide and quartz-sulphide veins with associated steeply-dipping, E-W to NW-SE trending, narrow, high-angle reverse-ductile and brittle-ductile shear zones superimposed on the regional foliation.

Structural observations strongly indicate that sulphide mineralisation predated D2, although at LaRonde-Penna there are indications of post D2 gold accumulation, while at Doyon there are several generations of gold-bearing structures ranging from pre-ductile deformation to late brittle phases. There is a strong correlation between copper and gold grades at Bousquet-LaRonde.

The Doyon Mine was owned and operated by Cambior Inc., produced 7.5 t (0.243 Moz) Au in 1999. Reserves at the end of that year were 10.62 Mt @ 6.3 g/t Au for 67 t (2.17 Moz) Au.
Between 1980 and 2005 the Doyon Mine produced 29.78 Mt @ 5.55 g/t Au for 165.14 t Au, with remaining reserves of 7.92 Mt @ 5.17 g/t Au for 10.9 t Au.
Between 1989 and 2005 the Mouska deposit yielded 1.51 Mt @ 11.55 g/t Au for 17.45 t Au, with remaining reserves of 0.38 Mt @ 14.4 g/t Au for 5.5 t Au.
Between 1942 and 1947 the Mic Mac deposit yielded 0.72 Mt @ 4.62 g/t Au for 3.34 t Au, with no remaining reserves.
These "intrusion related and shear zone hosted deposits" accounted for a total production + reserve of 40.32 Mt @ 5.77 g/t Au containing 232.51 t Au.

The Dumagami deposit produced 7.33 Mt of ore @ 6.27 g/t Au, 0.47% Cu, 0.07% Zn, 11.7 g/t Ag, containing 46.01 t Au, between 1988 and 1999.

Bousquet #1 & 2 were owned and operated by Barrick Gold Corp., and in 1999 milled 0.884 Mt of ore at an average head grade of 7.8 g/t Au and metallurgical recovery of 94.8% to yield 6.34 t (0,204 Moz) Au. At the end of the year reserves totalled 2.88 Mt @ 5.8 g/t Au (for 16 t, 0.52 Moz Au), while the additional resource was 2.05 mt @ 4.8 g/t Au (for 9.8 t, 0.316 Moz Au).
Between 1978 and 1996 Bousquet #1 produced 7.45 Mt @ 5.3 g/t Au for 39.5 t Au, with remaining reserves of 1.82 Mt @ 5.97 g/t Au.
Between 1990 and 2002 Bousquet #2 produced 8.14 Mt @ 8.1 g/t Au, 0.56% Cu for 66.25 t Au, with no remaining reserves.

LaRonde-Penna was owned and operated by Agnico Eagle. During 1999 0.814 Mt was milled at an average head grade of 4.1 g/t Au to yield 2.8 t Au, 8.6 t Ag, 4453 t Zn, 1495 t Cu. Reserves amounted to 31.55 Mt @ 3.16 g/t Au, 74 g/t Ag, 0.33% Cu, 4.78% Zn, with a total of 93.8 t (3.02 Moz) Au. Total production + reserves in 2006 were 58.76 Mt @ 4.31 g/t Au, 0.33% Cu, 2.17% Zn, 45 g/t Ag, containing 252.97 t Au (Mercier-Langevin, et al., 2007).
These "Au-rich VHMS deposits" of Dumagami, Bousquet #1 & 2 and LaRonde-Penna, accounted for a total production + remaining reserve of 92.36 Mt @ 5.0 g/t Au containing 461.71 t Au.

The most recent source geological information used to prepare this decription was dated: 2007.    
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.


  References & Additional Information
   Selected References:
Anonymous  1995 - Larondes golden future: in    Canadian Mining Journal, December 1995    pp 9-14.
Beaudoin G, Mercier-Langevin P, Dube B and Taylor B E,  2014 - Low-Temperature Alteration at the World-Class LaRonde Penna Archean Au-Rich Volcanogenic Massive Sulfide Deposit, Abitibi Subprovince, Quebec, Canada: Evidence from Whole-Rock Oxygen Isotopes : in    Econ. Geol.   v.109 pp. 167-182
Dube B, Mercier-Langevin P, Hannington M D, Lafrance B, Gosselin G and Gosselin P,  2007 - The LaRonde Penna World-Class Au-Rich Volcanogenic Massive Sulfide Deposit, Abitibi, Quebec: Mineralogy and Geochemistry of Alteration and Implications for Genesis and Exploration: in    Econ. Geol.   v102 pp 633-666
Galley A G and Lafrance B,  2014 - Setting and Evolution of the Archean Synvolcanic Mooshla Intrusive Complex, Doyon-Bousquet-LaRonde Mining Camp, Abitibi Greenstone Belt: Emplacement History, Petrogenesis, and Implications for Au Metallogenesis : in    Econ. Geol.   v.109 pp. 205-229
Mercier-Langevin P, Dube B, Hannington M D, Davis D W, Lafrance B and Gosselin G,  2007 - The LaRonde Penna Au-Rich Volcanogenic Massive Sulfide Deposit, Abitibi Greenstone Belt, Quebec: Part I. Geology and Geochronology: in    Econ. Geol.   v102 pp 585-609
Mercier-Langevin P, Dube B, Hannington M D, Richer-Lafleche M and Gosselin G,  2007 - The LaRonde Penna Au-Rich Volcanogenic Massive Sulfide Deposit, Abitibi Greenstone Belt, Quebec: Part II. Lithogeochemistry and Paleotectonic Setting: in     Econ. Geol.   v102 pp 611-631
Mercier-Langevin P, Dube B, Lafrance B, Hannington M D, Galley A, Marquis R, Moorhead J and Davis D W,  2007 - Preface to a Group of Papers Devoted to the LaRonde Penna Au-Rich Volcanogenic Massive Sulfide Deposit, Eastern Blake River Group, Abitibi Greenstone Belt, Quebec: in    Econ. Geol.   v102 pp 577-583
Scales M  1988 - Going for gold and getting it: in    Canadian Mining Journal, July 1988    pp 11-17

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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