Deposit Types
All mineralization at Cozamin occurs in veins, and fracture-controlled systems of veinlets. Currently mined mineralization at Cozamin is best described as intermediate sulphidation. The copper-rich intermediate sulphidation mineralization is an early phase that is enveloped, overprinted or brecciated by zinc-rich intermediate sulphidation mineralization. The copper veins are inferred to be higher temperature, have significantly fewer vugs and can be massive pyrrhotite-pyrite-chalcopyrite with little gangue. Zinc-rich veins also tend to be sulphide rich, like the copper-rich ones, but with slightly more gangue. Well-banded quartz, or quartz-carbonate veins are inferred to be lower temperature and best classified as low sulphidation. They often have open space filling textures with quartz druse vug linings and typically gold and silver rich with lesser base metals and are generally not being mined today, but were historically important.

This transition from intermediate sulphidation copper-dominant mineralization to intermediate sulphidation zinc-dominant mineralization is thought to be the result of an evolving, telescoped hydrothermal system. Blocks or fragments of massive chalcopyrite-pyrite-pyrrhotite mineralization enveloped by zinc-dominant mineralization are observed in drill core and in mine workings. This telescoping system is closely associated with the district’s largest center of rhyolite flow domes which may be the shallow expression ........

Cozamin uses LHOS as the primary bulk mining method, supported by horizontal drifting to develop the access for stoping. Historically, Cut-and-Fill mining methods and a version of the Modified AVOCA mining method have been employed at Cozamin but are not used in this Mineral Reserve estimate. The LHOS mining method has proven to be a scalable method for use at Cozamin, allowing production to steadily increase since Capstone took ownership. Major levels are separated by sill pillars and extend along strike to each extent of the vein domain being mined.

Longitudinal long-hole open stoping operates along or parallel to the strike of the vein. The orientation of the method means that the hangingwall and footwall of the vein will form the sidewalls of the stope. The method is commonly used in narrow-vein mines where the orebody continues for a large extent along strike and dip. LHOS requires competent rock in the hangingwall and footwall in order to support a large void. As employed at Cozamin, the LHOS method is entirely bottom-up extraction on retreat within stoping panels. Although the method requires high capital development ramp to access the development levels, much of the sublevel development necessary to expose stopes is mined economically as ore production as the cuts can be kept within the vein.

Cozamin backfills each stoping sublevel prior to mining the sublevel above. The backfill used is unconsolidated waste development rock from other areas of t ........

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