The Casa Berardi gold deposit can be classified as an Archean age, sedimentary-hosted lode gold deposit. Gold deposits of the Archean Abitibi greenstone belt dominantly consist of epigenetic disseminated and vein-hosted deposits, and syngenetic gold-rich massive sulphides (Robert et al., 2005; Monecke et al., 2017).

Three main groups of minerals are found in the mineralized material at the Casa Berardi Mine; silicates (quartz, albite, muscovite), carbonates (siderite, ankerite and dolomite) and sulphides (pyrite and arsenopyrite with traces of chalcopyrite and pyrrhotite). There is also gold mineralization found in a graphitic mud rock formation along the Casa Berardi fault plane. The historical recovery data suggest that material classified as “quartz ore” and is dominantly silicates and carbonates have better recoveries than sulphide dominant material, particularly those that contain arsenopyrite. Carbon in graphitic argillite rock at or near the Casa Berardi Fault can be “preg robbing” and influence gold recovery.

STYLES OF MINERALIZATION
VEINS
Gold mineralization is essentially located in quartz veining, either in the form of plurimetric veins, small-scale veins, or veinlet networks. Veins are heterogeneous and contain a variable percentage of foliated enclaves showing a laminated appearance. Veins are of different color, texture, and structure. Gold grades are generally correlated with increasing complexity. Different quartz phases have b ........

The ore at Casa Berardi is extracted using a combination of underground and open pit mining methods. The underground mines at Casa Berardi are trackless and are accessed by a combination of ramps and a production shaft. The mining method is longhole stoping using a combination of traverse and longitudinal orientations depending upon the widths of the zone. The combined ore production rate from the underground zones is in the range of 2,000 to 2,200 tons per day.

Open pit mining is used to extract near surface mineralization, both above the existing underground mining horizons and in areas without economic underground resources. At present, one open pit mine is in production and another is being developed. Three additional pits are anticipated. The combined ore production rate from the open pit zones is highly variable depending on the mining sequence and ore release rates. Open pit ore is fed to the plant roughly in equal proportion to the underground ore and any surplus is stockpiled.

Current reserves at the Casa Berardi mine comprise eight zones at the West Mine, spread over a moderate horizontal distance from each other and located at different mine elevations, plus open pit and underground areas at the East Mine. The 113, Lower Inter, 118, 121, 123, 124 (Principal underground and open pit), 134, and the West Mine Crown Pillar ("WMCP") open pit zones in the West Mine, and the 148 Zone (open pit and underground) and the 160 open pit in the East Mine ........

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Ore is hauled by truck from the West Mine headframe complex to the crusher dump pocket, which is equipped with a static grizzly and a pneumatic hammer to break any oversize material. Ore passing the grizzly is screened again on the scalping screen. The oversize ore is fed to a jaw crusher and its discharge rejoins the scalping screen undersize. The crushed ore is stored in the ore storage bin.

GRAVITY CIRCUIT
The gravity circuit feed, coming from the primary cyclone underflow, is split to feed two parallel gravity circuits. Each circuit consists of a vibrating screen and a gravity concentrator. The screen oversize from each circuit reports back to the ball mill and the screen undersize feeds a gravity concentrator. The concentrator’s tailings are pumped to the secondary cyclones pump box. The gravity concentrate flows to an intensive cyanidation reactor (Inline Leach Reactor, or ILR) for leaching. To promote gold leaching and control the pH, oxygen peroxide, cyanide ........