Summary:
Intrusion-associated disseminated sulphide mineralization is commonly found along the PDMFZ and, as its name implies, is spatially related to porphyritic intrusions. Two areas have a large number of these mineralized zones: the periphery of the Duparquet basin and the Fayolle deposit area. Two subtypes have been identified based on intrusion composition: calc-alkaline and alkaline (Legault et al., 2006). The Fayolle occurrence has been described in the past as a calc-alkaline quartz-feldspar porphyry (QFP) or feldspar-porphyry (FP) intrusion-related disseminated sulphide deposit (Legault et al., 2006). However, the newly geological understanding of the Fayolle deposit differs from this earlier description.
The Fayolle deposit is characterized by the komatiite flows of the Lanaudiere Formation (Goutier, 1997) intruded by a swarm of quartz-feldspar porphyry and/or feldspar porphyry dykes. A post-intrusive brecciation event seems to control gold deposition. The breccia zones mostly affect the ultramafic flows, but also locally contain felsic dyke fragments.
The northern part of the Fayolle Property is underlain primarily by the Lanaudière Formation, which corresponds to the summit of the Kinojevis Group. Basalt is the dominant rock type, and basalt layers are intercalated with felsic and ultramafic rocks. Also observed are ultramafic flows, magnesian basalt, and komatiite characterized by breccia, cumulates and spinifex texture. The east-trending Manneville North Fault bifurcates as it passes through this part of the Property, placing a wedge of the Lac Caste Formation of the Kewagama Group into faulted contact with the Lanaudière Formation along the north and south sides of the fault. The Lac Caste Formation comprises bands of turbiditic sedimentary rocks, consisting of beds of sandstone and mudrock with black siliceous argillic horizons.
The roughly central part of the Fayolle Property is underlain, from north to south, by the Lac Caste Formation of the Kewagama Group and the Malartic Group. The faulted contacts between these formations and with the Lanaudière Formation to the north represent bifurcations of the Manneville South Fault. The Malartic Group is composed of ultramafic flows, andesite and intrusions. The southernmost and westernmost ends of the Property are occupied by the Mont-Brun Formation, which represents a central band of turbiditic sediments within the Kewagama Group. This formation is composed of pale grey sandstone and grey mudrock representing thin beds deposited by turbidity currents. The contact between the MontBrun Formation and the volcanic units of the Malartic Group is marked by the southeasttrending La Pause Fault.
Several gold occurrences are present on the Fayolle Project. They all occur along interfaces marked by strong magnetic contrasts, which are evident on local and regional magnetic maps. The most important known occurrence is the Fayolle gold deposit for which resources have been estimated (refer to Section 14: Mineral Resource Estimates). Other gold occurrences of the Project remain within less than 1 km from the Fayolle deposit.
The Fayolle deposit comprises wide alteration zones that contain brecciated mineralized zones. Gold mineralization is hosted in porphyritic dykes of intermediate composition and in volcanic rocks (Gaudreault and Beauregard, 2009). The main lithology intersected in drill hole is magnetic komatiite. Locally, primary volcanic textures, such as varioles and spinifex, are observed beyond the mineralized zones (Carrier, 2007). Spinifex texture was observed in komatiites, whereas the varioles suggest that mafic volcanic rocks are intercalated with the komatiites. Most examples of varioles from the southwestern Abitibi Subprovince are plagioclase spherulites, which are always found in aphyric tholeiitic basalts inferred to have been superheated during eruption (Arndt and Fowler, 2004). The volcanic rocks of the Fayolle deposit are intruded by dykes ranging from monzonitic to dioritic and/or granodioritic composition. The rocks are generally brecciated with little clast rotation and cemented with ankerite.
Most of the ankerite and quartz-ankerite veins occur in brecciated rocks. Several ankerite and quartz ankerite veins, 0.5 to 2 cm wide, as well as chlorite-filled fractures and gouge with irregular orientations, have been observed within and near the mineralized zones. Vein density increases from 5% to 80% in the mineralized zone, and fuchsite alteration is locally observed.
Mineralization is characterized by disseminated pyrite (generally 1-5%) spatially associated with or contained within veinlets of quartz and/or carbonate minerals. Gold is present in the pyrite or as grains of free gold in quartz veinlets. Pyrite is generally found as pods and fine-grained disseminations along schistosity planes and chloritized fractures which are variably deformed at dyke contacts. Pyrite also occurs as barren cubic grains (up to 12%) in the host rocks, and pyrite content is therefore not a direct indicator of gold mineralization in the Fayolle deposit (Carrier, 2007).
Summary:
Ore Handling and Crushing
Underground ore is hoisted to surface and hauled by truck to the processing facility located 2.5km from the mine shaft. The ore is discharged at the crusher house. The ore is fed to a single stage jaw crusher (1.07 x 1.22m) by a front-end loader through a grizzly feeder. The ore is conveyed to the mill ore bins using a belt conveyor system. Each bin has a capacity of 2,800dmt.
Grinding and Gravity
Grinding of the Westwood ore is done using a 2,700HP semi-autogenous grinding (SAG) mill in closed circuit with primary hydrocyclones. The overflow of primary hydrocyclones feeds a 1,000-HP ball mill in closed circuit with its secondary hydrocyclones. A portion of the underflow (secondary hydrocyclones) feeds the gravity separation circuit composed of a sweco screen, Knelson concentrator (30’’) and a shaking table. The tail of the gravity circuit returns to the grinding circuit and the gravity gold concentrate goes to the refinery. The targeted grind size is 80% passing 53 microns (270 mesh).