The Côté Gold deposit is a new Archean low-grade, high-tonnage gold (± copper) discovery. It is described as a synvolcanic intrusion-related and stockwork disseminated gold deposit (Kontak et al., 2012, Katz et al., 2015, Dubé et al., 2015, Katz, 2016).

The Côté Gold deposit appears to correspond to the porphyry style. It is located in the southern limb of the Swayze greenstone belt part of the gold-rich Abitibi subprovince. At Côté, the zones of mineralization are centred on multi-phase magmatic and hydrothermal breccias, including a mineralized Au-Cu±Mo±Ag hydrothermal breccia that intrudes tonalitic and dioritic phases of the CIC (Katz et al., 2015). U-Pb zircon and titanite and ReOs molybdenite dating highlights the co-temporal link between magmatism and hydrothermal events (Katz, 2016). The hydrothermal breccia is itself overprinted by several types of hydrothermal alteration associated with mineralization.

Two different types of gold mineralization are recognized on IAMGOLD’s Chester township properties. The historically important mineralization can be termed quartz vein and fracture associated (Type 1), while the new Côté Gold deposit is interpreted by Kontak et al. (2012) as an Archean intrusion-related Au(-Cu) deposit (Type 2).

The Côté, Type 2, gold mineralization consists of low- to moderate-grade gold (±copper) mineralization associated with brecciated and altered tonalite and diorite rocks.

Several styles of Au mineralization are recognized within the Côté Gold deposit, and include disseminated, breccia-hosted and vein-type, all of which are co-spatial with biotite (± chlorite), sericite and sodic alteration.

Disseminated mineralization in the hydrothermal matrix of the breccia is the most important style of Au(-Cu) mineralization. This style consists of disseminated pyrite, chalcopyrite, magnetite, gold (often in native form), and molybdenite in the matrix of the breccia and is associated with primary hydrothermal biotite and chlorite after biotite.

The nature of the veins and fractures vary from stockworks to closely spaced, planar, subparallel sheeted vein sets. Stockwork mineralization cuts through all major rock types, but is most prominent in the more brittle tonalitic phases versus the dioritic phases and formed during the biotite alteration event (Katz et al., 2015; Katz, 2016). The mineralized sheeted veins and stockwork zones cut the hydrothermal breccia and therefore post-date the breccia-controlled mineralization.

Visible gold is observed in several settings within the deposit:

• Quartz ± carbonate ± biotite/chlorite veins: gold is observed to be hosted within the vein quartz and also along fractures cutting the vein. Sulphides include pyrite, chalcopyrite and pyrrhotite.

• Sheeted syn-intrusion-related veins: a set of subparallel, sheeted, millimeter to decimeter scale quartz ± carbonate ± chlorite veins with 0.5% to >50% pyrite ± chalcopyrite ± pyrhotite that commonly contain millimeter to centimeter scale barren sericite alteration haloes. These veins have been interpretated to be syn-intrusion in timing (Smith, 2016) and are also found outside the deposit within the CIC (e.g., Chester 1, 2 and 3).

• Magmatic-hydrothermal breccia: gold is more commonly observed in larger, welldeveloped shoots but is also observed in submillimeter veinlets of obvious hydrothermal provenance. At hand sample scale, gold appears to have some correlation with chlorite, sulphides, and magnetite.

• Miaroles: gold is observed hosted within miarole quartz, in fractures cutting primary miarole minerals, and within the host rock, proximal to the host/miarole interface commonly within a moderate to intense silica and/or sericite alteration halo. Importantly, the hydrothermal system is observed to replace the common carbonate cores of miaroles, which may subsequently host gold.

• Alteration related/ /disseminated: gold is observed proximal to veining and within apparent sodic ± sericite ± biotite/chlorite alteration halos. It is also found as isolated grains with no apparent control or related structure most commonly in tonalites, but also in diorites, commonly with moderate to intense sodic and/or sericite alteration of the host. It may also be associated with biotite/chlorite.

The hydrothermal breccia and the associated hydrothermal alteration zones are the material component of the mineralization providing the mineable widths and grades to the deposit. Areas outside of its significant development are likely not a significant contribution to economically important mineralization. The various gold-bearing quartz vein systems, also found immediately adjacent to the pit, serve to upgrade the hydrothermal envelope where they are present. The amount of gold contributed by these quartz vein systems to the deposit is difficult to determine but is thought to be of some significance to overall metal content.

The Base Case mine plan is designed as a truck- shovel operation assuming 220-t autonomous trucks and 34 m3 shovels. The pit design includes four phases to balance stripping requirements while satisfying the concentrator requirements.

The design parameters include a ramp width of 35 m, road grades of 10%, bench height of 12 m, targeted mining width between 90 m, berm interval of 24 m, variable slope angles by sector and a minimum mining width of 40 m.

The smoothed final pit design contains approximately 203 Mt of mill feed and 492 Mt of waste for a resulting stripping ratio of 2.4:1. The 203 Mt processed fits within the maximum capacity of the TMF. The average grade of this material is 0.98 g/t Au. These tonnages and grades were derived by following an elevated cut-off strategy in the production schedule.

The Mine Rock Area (MRA) will be constructed southeast of the planned open pit to store mine rock from the open pit excavation. The rock piles will be built in 10 m lifts with 25.5 m benches to provide an overall safe slope of 2.6H:1V. The inter-bench slopes will be at the angle of repose of the rock. In its ultimate configuration, the MRA will store 350 Mt of mine rock with its final crest elevation at an approximate elevation of 480 m.

Collection ditches and six runoff collection ponds/sumps will be built at topographical low points around the MRA perimeter to collect runoff and seepage, which will then be pumped to the polishing pond.

The overburden storage, which will be located to the southwest of the pit, will have a storage capacity of approximately 8.2 Mm3.

The stockpiles will contain stripped materials from all excavations from the project development. The stockpiled materials will be used for rehabilitation applications at closure. Sedimentation ponds will be built to settle out solids before release to the environment.

The ore stockpiles will be located on the north side of the pit and have a total storage capacity of 23 Mm3 , which is enough to satisfy the maximum stockpiling capacity of approximately 48 Mt required in the production schedule.

Plant throughput will be 36,000 t/d and it is expected that a ramp-up period of 10 months will be required to reach the design throughput.

The Base Case process plant will consist of:
- Primary (gyratory) crushing
- Secondary cone crushing and coarse ore screening
- Coarse ore stockpile (COS)
- Tertiary HPGR crushing
- Fine ore screening and storage
- Two milling stages (ball mill followed by vertical stirred mills)
- Gravity concentration and intensive leaching
- Pre-leach thickening
- Whole ore cyanide leaching
- CIP recovery of precious metals from solution
- Cyanide destruction
- Tails thickening
- Elution of precious metals from carbon
- Recovery of precious metals by EW
- Smelting to doré.