Recent geoscientific work and observations suggests an iron oxide-copper-gold (IOCG) deposit class with a magmatic-hydrothermal origin for the ICP deposits.

Mineralization at the ICP is Type 1 characterized as syngenetic, stratiform/tabular exhalative deposits within, or closely associated with, the mafic sequences of the Apple Creek Formation. This mineralization is dominantly bedding concordant and the deposits range from nearly massive to disseminated. Some crosscutting mineralization is present that may be in feeder zones to the stratiform mineralization or may be due to remobilization locally into fracture quartz veins and/or crosscutting structures.

Dominant minerals include cobaltite (CoAsS) and chalcopyrite (CuFeS2), with lesser, variable occurrences of gold. Other minerals present in small quantities are pyrite (FeS2), pyrrhotite (FeS), arsenopyrite (FeAsS), linnaeite ((Co Ni)3S4), loellingite (FeAs2), safflorite (CoFeAs2), enargite (Cu3AsS4) and marcasite (FeS2).

Recently, rare-earth minerals have been identified in samples from the deposit as monazite, xenotime and allanite. At this time, these minerals have not been considered for potential recovery as by-products of the Co-(Cu-Au).

The Ram is the largest and best-known deposit in the ICP area. It consists of a Hanging-wall Zone with 3 primary and 4 minor horizons, a Main Zone comprising 3 horizons, and a Footwall Zone with 3 horizons. These sub-parallel horizons generally strike N15oW and dip 50o – 60o to the northeast. Most of the significant Co mineralization is associated with exhalative lithologies i.e. biotitic tuffaceous exhalate (BTE), siliceous tuffaceous exhalate (STE), and quartzite with impregnations of biotitic tuffaceous exhalate (QTZ/BTE) or siliceous tuffaceous exhalate (QTZ/STE).

The Sunshine/East Sunshine deposit is FCC’s second best known deposit within the ICP area and is located about a mile south of the Ram deposit. Mineralized zones are typically multiple, stacked sulphide-bearing beds. Individual mineralized beds or horizons are intimately associated with biotite-rich tuffaceous exhalative (BTE) horizons. An increase in silica content generally indicates an increase in cobalt, copper and gold grades.

The mining methods proposed for the Ram deposit are longitudinal longhole stoping and overhand cut and fill.

The selection of these mining methods for the deposit was determined primarily by the geometry of the mineralized horizons, including factors such as its continuity, dip and width, and the geotechnical parameters of the rock mass.

The Ram deposit is composed of numerous parallel mineralized horizons, with thickness ranging from one foot to more than 20 ft., at an average dip of 55° (Samuel, 2015). Currently, only three horizons within the main zone containing the majority of the mineralization are considered in the mine design, plan and mineral reserve. These are horizons 3021, 3022 and 3023.

Cut and fill mining will be applied to areas dipping less than 50°, or in stopes having widths ranging from 6 to 10 ft. Conventional cut and fill mining, using hand-held pneumatic drills, will be carried out in areas having economic mineralized width ranging from 6 to 8 ft. Areas having widths ranging from 8 to 10 ft. will be mined by mechanized cut and fill. Horizons wider and steeper than 10 ft. and 50° will be mined with longitudinal longhole stoping. Small and mid-sized mining equipment was selected to provide a higher selectivity for the proposed mining methods.

The ratio of mineral reserve that will be extracted through longhole stoping and cut and fill mining methods is 70% and 30% respectively. In combination, these two mining methods provide a production capacity in the underground mine that is higher than the nominal mill capacity (800 t/d). The mine has the capacity to supply approximately 323,000 t/y of ore to the mill during steady state operation, equivalent to approximately 880 t/d production rate for 365 d/y. The proposed mine working schedule is two 12 hours shifts for 7 days a week. Conservatively, the mine operating cost estimates have been based on achieving this higher rate of production, whereas in practice it is anticipated that production would keep pace with milling, and so mining expenditures that are projected over a period of 12 years would in fact be spread over the whole of the mill operating life of approximately 12.5 years.

The recovery of all products is completed in a two-step process in separate locations. Initially, a flotation concentrate containing cobalt, copper and gold is produced at the mine site near Salmon Idaho, which is transported for processing at the Cobalt Processing Facility (CPF) located near Blackfoot, Idaho. The valuable products from the CPF include cobalt sulphate, copper sulphate, gold on activated carbon and magnesium sulphate.

The primary facilities at the mine site include the concentrator, paste backfill plant and the water treatment plant.

Primary crushing is via a jaw crusher (22” x 36”) with secondary crushing via a cone crusher (4 foot). The product from the primary crushing circuit has a nominal 80% passing (P80) size of 2.5 inches. The secondary crusher operates in closed circuit with a double deck sizing screen. The product from the secondary crushing circuit has a nominal P80 of ?-inch which is stored in the 400 capacity fine ore storage bin. Ore from the storage bin is transported at a controlled rate to a grinding ball mill via a conveyor.

Ore from the crushing circuit is transported via the mill feed conveyor into the ball mill feed chute at a nominal rate of 36.2 T/h. Ore, process water and potassium amyl xanthate (PAX) are fed to the mill, which is operated in closed circuit with two parallel hydrocyclones. The circuit is designed with a circulating load of 300 % of the feed. The cyclone overflow product with a target P80 of 70 µm gravitates to the flotation conditioner.

The flotation circuit consists of a conditioning tank, rougher flotation cells and cleaner flotation. Frother and additional PAX is added to the slurry in the agitated conditioning tank. The slurry from the conditioner feeds the rougher flotation bank which comprises two banks of four flotation cells. The rougher flotation tailings are the final tailings from the concentrator.

The concentrate from the rougher flotation circuit is collected and pumped to the distribution box in the cleaner flotation circuit. The distribution box feeds the cleaner flotation bank, which comprises two banks of six cleaner flotation cells. The tailings from the cleaner flotation circuit are recycled to feed the rougher flotation circuit. If the metal concentrations in the cleaner tailings are sufficiently low, they can be pumped directly to the tailings thickener.

The cleaner concentrate is the final product of the flotation circuit. The mass of the concentrate is typically reduced to about 9% of the mass of the feed to the circuit. The cleaner concentrate is pumped to the concentrate thickener.

The final flotation concentrate feeds the concentrate stock tank for storage prior to dewatering in the concentrate filter press. The concentrate is trucked to the CPF refinery for final processing.

The tailings from the flotation circuit are pumped to the tailings thickener. Flocculant is added to the thickener in order to enhance the settling of the solids. The water recovered in the thickener overflow is stored in the process water tank for reuse in the circuit. The thickener underflow slurry is pumped to the mine backfill system.

The thickened tailings are filtered using a vacuum disc filter and the filter cake is either conveyed to a storage area from which it is loaded into trucks to be transported to the tailings storage facility or it feeds the backfill mixer where it is blended with cement and water then pumped underground to be used as paste backfill.

The CPF design is a hydrometallurgical processing facility located near Blackfoot, Idaho. It is a sophisticated process that uses a complex series of unit operations to produce a number of products. The processes include pressure leaching in autoclaves, solvent extraction, crystallization, precipitation, thickening and filtration. Flotation concentrate from the mine site is shipped to the CPF for processing into saleable products. The residue produced in the refinery is shipped via rail using side dump cars to an offsite waste facility. Waste effluent from the site is disposed of in the municipal sewer line for treatment in Blackfoot, Idaho.