Mineralization at Kutcho comprises three known “Kuroko-type” VMS deposits aligned in a westerly plunging linear trend. The largest, the Main deposit, comes to surface to the eastern end, followed by Sumac down plunge, and Esso to the western end which occurs at depths of about 400 m below surface.
“Kuroko-type” VMS deposits are typically related to felsic volcanism in island arc or back-arc tectonic settings. Features of the Kutcho deposits suggest that they formed at or near the water-seafloor interface in a structurally controlled depression, such as a half-graben type structure. The chemical composition of the alteration around the Kutcho deposits is well zoned about the hydrothermal vent areas. Mineralization consists of a pyritic footwall with zoned copper and zinc towards a sharp hanging wall contact.