The Galore Creek property is interpreted to be an example of an alkalic porphyry copper–gold–silver system.

The Project is situated within the Stikine Terrane, an exotic terrane accreted to the ancestral North American craton. A sequence of Permian, Mississippian and Devonian age calc-alkaline and bimodal flows and volcaniclastic rocks, interbedded carbonate and minor shale and chert, termed the Stikine assemblage, form the basement of the terrane. Unconformably overlying the Stikine assemblage is a succession of Lower to Middle Triassic sedimentary and upper Triassic volcanic rocks.

The Galore Creek Syenite Complex, of Tertiary age, is centered in the west fork of Galore Creek and is 5 km in length and 2 km in width. The deposits are hosted by potassium-enriched volcanic rocks and pipe-like breccias adjacent to syenite stocks and dykes. They are manto-shaped, and trend north to northeast, following either, or both, syenite contacts and structural breaks. To date, 14 deposits and prospects have been identified, five of which, the Central Zone, Southwest Zone, Junction Zone West Fork Zone and Middle Creek Zone are of economic interest.

The Galore Creek property has undergone at least three temporally different mineralizing events. These include the early formation of the nearby Copper Canyon eruptive centre and its associated mineralization; deposition of the Central Zone mineralization at the Central and Junction deposits, and the Butte prospect; and emplacement of the West Fork mineralization at the Southwest and West Fork deposits.

Bornite and generally higher-grade gold are developed in the intense potassic alteration zone, and are associated with magnetite and sparse pyrite. Within the propylitic zone, zones of moderate potassic alteration have developed, and have associated chalcopyrite and pyrite mineralization. External to these potassic zones, but still within the propylitic zone, replacement lodes of gold, silver and base metals have formed.

In the opinion of the QPs, knowledge of the deposit settings, lithologies, and structural and alteration controls on mineralization is sufficient to support Mineral Resource and Mineral Reserve estimation. The mineralization style and setting of the Project deposit is also sufficiently well understood to support Mineral Resource and Mineral Reserve estimation. Prospects and targets are at an earlier stage of exploration, and the lithologies, structural, and alteration controls on mineralization are currently insufficiently understood to support estimation of Mineral Resources.

The proposed Project will be a conventional, large-tonnage, open-pit operation with approximately 528 Mt of ore processed over the life-of-mine, at a nominal daily throughput of 95,000 t/d.

Because of the revised Mineral Resource estimate, and changes to the metallurgical recovery assumptions and different commodity price assumptions, AMEC redeveloped the mine plan for the Project.

The mine plan for Galore Creek deposits was based on mining six separate phases that were developed from detailed designs based on optimized WhittleTM pit shells for four open pits, at Central, Junction, West Fork, and Southwes.

Mining equipment selection was based on the mine production schedule and equipment productivities, as well as consideration of workforce and operating hours. The operation will use a conventional truck-and-shovel fleet. In the opinion of the AMEC QPs, the fleet is appropriate to the planned production schedule.

The design criteria for the process plant were based on processing ore through a conventional crushing, grinding and flotation plant using conventional processes and equipment. The plant is proposed to handle a blend of ore from the various zones of the Galore Creek deposits. A no-stockpile blending strategy will be utilized to deliver consistent copper grades to optimize process plant performance.

Run-of-mine (ROM) ore will feed a single gyratory crusher in the Galore Creek Valley. Crushed ore will then be transported via three overland conveyors from Galore Creek Valley, through the access tunnel to the West More Valley, to a single coarse ore stockpile near the mill site that will be adjacent to the proposed West More tailings facility.

Apron feeders will reclaim ore from the coarse ore stockpile to feed a semi-autogenous grinding (SAG) mill. SAG discharge material will be screened, with coarse pebbles reporting to two cone crushers before reporting back to the SAG feed stream. SAG discharge undersize material will be split between three ball mills in closed circuit with hydrocyclones. The hydrocyclone overflow, with a target 80% passing size of 200 µm, will report to flotation for further processing.

Standard process reagents will be added prior to flotation to allow efficient separation of valuable minerals. Some ores will require the addition of a talc depressant to maximize recovery while achieving acceptable concentrate grades.

The flotation circuit will consist of two parallel rougher banks, with the rougher concentrate reporting to regrinding. Regrind will occur in four vertical tower mills, with a gravity concentrator installed parallel to the tower mills to remove any build up of high density material in the regrinding circuit. The gravity concentrate will report to the final copper concentrate stream.