The Carmacks copper-gold deposit is similar to the Minto deposit, located 50 km to the northwest (Sinclair, 1976; Pearson, 1977), except that the Minto deposit is flat lying and primarily a sulphide deposit. A number of theories for the genesis of the Carmacks deposit have been postulated over the years and by different operators. The Cu-Au- Ag metal tenor and association with Late TriassicEarly Jurassic granodiorites would appear to suggest a link between mineralization at Carmacks and the porphyry copper deposits of the same age that occur across British Columbia. However, the linear deposit shape, lack of mineralized material-stage veining and lack of porphyry alteration show clearly that the Carmacks copper deposit is not a classic porphyry system. Evidence from the drilling campaigns suggests the deposit was formed by assimilation of older, copper bearing volcano-sedimentary rocks into the Jurassic Granite Batholith. These “rafts” of mineralized rock would have been variably metamorphosed, and in places completely assimilated into the granodiorite. The volcano-sedimentary rafts would tend to pull apart along bedding planes forming large tabular sheets as observed in Zones 1, 4, 7, 7A, 8, 12, 13 and 2000S. Evidence suggests the sulphide mineralization has been remobilized out of the rafts into the surrounding diorite. At a later time, when the upper parts of the batholith where eroded and the rocks were exposed to the atmosphere and meteoric waters, the sulphide mine ........

The Carmacks project will be developed as an open pit mine. Mining will be conducted on two 12- hour shifts per day for 335 days per year. It was specified that this was to be envisioned to be conducted with three mining crews using a 20-day on/10-day off rotation.

Four mining phases were designed for the Carmacks Project. Inter-ramp slope angles are 52.6°. The design is also based on 10 m mining benches in a double bench configuration for final walls. The main road is 25 m wide at a maximum grade of 10%. This will accommodate trucks of approximately 90 t such as Caterpillar 777 class trucks.

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The copper and gold recovery process was designed on the basis of 4,860 t/d with average head grades of 0.98% Cu and 0.435 g/t Au.

A jaw crushing plant will operate at a nominal crushing rate of 312 t/h, 16 hours a day for 365 days per year. The process plant will operate 24 hours per day for 365 days per year with a plant availability of 92% and a processing rate of 220 t/h. The copper will be leached with sulphuric acid, recovered in a solvent extraction / electrowinning circuit (SX-EW) and shipped as cathode copper. The copper circuit tailings is leached in CIL tanks and the carbon is processed in a 2 t/d carbon ADR plant for gold extraction and the production of gold doré. This process will achieve an estimated recovery of 85.2% Cu and 84.4% Au.

Copper Leaching and Recovery
Copper Leach and Counter Current Decantation Circuits
Cyclone overflow will feed the pre-leach thickener. The thickener overflow will be collected in the process water tanks and ........