The origin of the gold in the Doyon-Bousquet-Laronde (DBL) mining camp has been extensively debated in the past and three models have been proposed: synvolcanic, multi-stage, and syn-deformation. Recent and current studies of the Laronde-Penna deposit, Westwood ore zones, and Mooshla intrusion mineralisation, combined with the geological synthesis of the DBL mining camp (Mercier-Langevin et al., 2009), have provided further insights into the synvolcanic model for the introduction of the gold.

Five deposit and occurrence styles are recognized in this camp: 1) gold-rich base metal massive sulphide lenses (Laronde-Penna, Bousquet 2-Dumagami and Warrenmac lens), 2) gold-rich vein stockworks and sulphide disseminations (Bousquet 1, Westwood and Ellison);, 3) intrusion-related Au-Cu sulphide-rich vein systems (Doyon, Mooshla-A), 4) shear-hosted Au-Cu-sulphide-rich veins (Mouska and MicMac) and 5) syn-deformation auriferous quartz-pyrite-tourmaline veins (Mooshla-B).

On the Westwood project, Zone 2 Extension mineralisation share similarities with the Doyon mine intrusion-related veins system while the Warrenmac-Westwood Corridor may be related with the volcanogenic massive sulphide lenses of the Laronde-Penna and Bousquet 2-Dumagami mines. The North Corridor mineralisation shows hybrid characteristics between the two previous corridors.

Excluding the Doyon Mine area, mineralisation in the Westwood deposit consists of multiple horizons grouped in three distinct mineralised corridors from North to south (Wright-Holfed et al., 2010; Mercier-Langevin et al., 2009): the Zones 2 Extension corridor, the North Corridor and the Warrenmac-Westwood Corridor. Gold is generally associated with the presence of base metal sulphides in each corridor.

The Zone 2 Extension mineralisation consists of quartz-pyrite veins and veinlets with variable but usually minor amounts of chalcopyrite and sphalerite. They are generally less than 15 centimetres thick and are hosted in sericitized wall rock containing 2 to 10% disseminated pyrite. The vein system is roughly oriented N85-105° with a dip varying between 60-70°S and is slightly discordant to the regional foliation and S0 planes (direction and dip). Free gold, at the origin of high-grade values, is frequently observed in those veins. The veins are highly strained and associated with a proximal sericite-pyrite-quartz-±garnet alteration assemblage. Analogies with the Doyon Mine’s intrusion-related Zone 2 may reflect a similar origin.

The North Corridor mineralisation is characterized by quartz-pyrite veins and/or concentrations with locally abundant sphalerite-chalcopyrite±pyrrhotite when approaching the Warrenmac-Westwood Corridor. The amount of sulphide is variable within centimetre- to decimetre-wide veins and veinlets. The system is generally parallel to the Zone 2 Extension corridor with a dip ranging from 70-80°S and is also weakly discordant from the regional foliation. Occasional free gold is also present in the veins. Mafic to intermediate volcanic rocks host the North Corridor. Some veins share some analogies with the Zone 2 Extension corridor veins while others are comparable to Warrenmac-Westwood veins, suggesting different, multiple or hybrid origins.

The Warrenmac-Westwood corridor consists of auriferous semimassive to massive sulphide lenses, veins and disseminations containing variable but significant amounts of Cu, Zn and Ag (Mercier-Langevin et al, 2009). The mineralisation is characterized by pyrite–sphalerite–chalcopyrite– pyrrhotite veins, stringers and massive sulphides associated with variable amount of quartz and rare visible gold and galena. The sulphides are also enriched in the epithermal suite of elements (e.g. As, Sb, Bi, Pb, Se, Te, and Hg). These ore zones are a few centimetres to more than 50 centimetres thick in a disseminated pyrite- and sericite-rich altered halo reaching thicknesses of up to 10 metres. Local massive to semimassive sulphide lenses ranging from 1 to 14 metres are also observed within the corridor. This corridor is thought to be a gold-rich volcanogenic massive sulphide horizon. The system is generally parallel to the Zone 2 Extension and North Corridor with dip ranging from 70-80°S, also weakly discordant to the regional foliation.

Development is classified as either deferred (infrastructure) development, including ramps, cross-cuts and ore passes, or current development. Most lateral development is mechanized, with jumbos, rockbolters, scissor-lifts and 3.5 yd³ scoop-trams. Dimensions for waste drifts (including ramp below 600-level) are 3.8 m high x 3.7 m wide. Drift dimensions in the ore zone may vary locally according to the dip of the vein and the mining method selected: planned dimensions are drifts and 3.8 m wide x 3.7 m high for longhole drifts. Trolley drifts will be developed with wheeled long-tom teams: other than Level 840 (originally an exploration drift), dimensions are 3.4 m high x 3.1 m wide.

Arched backs will be required for drifts developed in certain geological units to assist with stability. Ground support varies significantly by type and orientation of the excavation: typical support may include mechanical rock bolts, resin rebar, friction bolts as well as mesh screen and straps.

Vertical development is mainly related to infrastructure development, including ventilation raises and ore/waste passes. Dimensions are typically 2.4 m x 2.4 m, although the main ventilation raise will have be 6 meters in diameter. Raise development is performed by contractors, including IAMRock (internal contractor); Alimak and conventional raise methods are currently used. Slot openings for longhole stopes will be drilled with V-30 heads (0.76 m diameter) on Cubex production drills.

Ore processing utilizes the pre-existing Doyon carbon-in-pulp (“CIP”) mill complex.

Ore from the Westwood underground is hauled to the Doyon mill (two kilometres away) to be crushed and ground. The ore grinding circuit utilizes a SAG mill and a 1,000 HP ball mill.