The Project Area hosts two principal styles of mineralization that have been the target of past and current exploration. The first and older style is porphyry Cu-Au mineralization related to intrusion and alteration by Late Triassic alkalic to sub-alkalic diorite to monzonite dykes and stocks exemplified by the Central Zone and Donnelly Deposit. The second comprises later, structurallyhosted and high-grade gold zones associated with shearing, fracture zones and quartz-carbonate vein/fault controlled pyrite, arsenopyrite, sphalerite, galena and chalcopyrite hosted by altered volcanic units and monzonite dykes.

Porphyry-Style Mineralization - Central Zone
Porphyry-style Cu-Au mineralization occurs within a north-south trending, moderately west dipping and fault-bounded structural panel of Triassic Stuhini volcaniclastic lithologies intruded by syn- to late-mineral monzonite dykes. Porphyry- style mineralization has been defined over a strike length of 1,000 m, with widths of 70 m to 200 m, it has been tested to 400 m downdip and it remains open along strike and downdip.

Mineralization occurs as quartz-pyrite-chalcopyrite with or without magnetite veinlets, stockworks, fracture fills and fine grained disseminations of pyrite and chalcopyrite. Metal grades appear to be directly related to the abundance of quartz-sulphide-magnetite vein development.

Porphyry-Style Mineralization - Donnelly Deposit
Of the many porphyry Cu-Au prospects located on the GJ claims block, the most advanced is an area measuring 3.5 km east-west and north-south where disseminated, fracture, quartz vein and quartz stockwork-controlled pyrite with variable chalcopyrite, rare bornite and trace molybdenite mineralization containing elevated gold values occurs. This area contains the Donnelly Deposit, the North Donnelly deposit and the GJ and North zones.

Typically, the best chalcopyrite mineralization occurs where pyrite is weaker and IP chargeability responses are moderate, which generally occurs on the flanks of more intense chargeability anomalies. Secondary magnetite, generally associated with chalcopyrite, is found as disseminations, irregular clots, in veins with K- feldspar with or without chlorite and/or epidote and/or as fillings in single or sheeted fractures that are one to three millimetres thick and millimetres to 10 cm apart. Exceptions to this association (the Donnelly Deposit and portions of the North zone) appear to be where magnetite has been altered to hematite.

Porphyry-Related, Vein-Hosted Mineralization
The second style of mineralization found on the Project Area comprises higher grade gold mineralization that post-dates the porphyry Cu-Au mineralization described above. It is structurally controlled in that it occurs in veins, fracture zones and stockwork crackle zones and as gold- bearing quartz-carbonate-sulphide veinlets and stockworks proximal to faults and shear zones. Petrographic work by Oliver (2016) indicates gold is associated with late fractures/microveinlets in high sulphide veinlets cutting arsenopyrite, which is one of the younger veining events. Gold also occurs as free gold within strongly fractured and strongly chlorite-sericite-calcite-pyrite altered zones with no associated sulphide veining but close associations to coarse grained laths of chlorite and sericite, and only a weak linkage to secondary K-feldspar or quartz. Gold mineralization often shows additional enrichment of Ag, Cu, Pb, Zn, As and Sb.

Conventional truck and shovel open pit mining was selected because, overall, it represents the least risk, most sustainable option from both economic and environmental perspectives.

During Stage 1, plant feed comprises 100% feed from Donnelly Pit, at a rate of 10,000 tpd, from which gold gravity concentrates are produced for sale in the market. Phase 3 starts in Production Year 12 when plant feed once again comprises 100% feed from Donnelly Pit, but at a rate of 30,000 tpd.

Stage 1 (10,000 tpd)
Processing during Stage 1 will be by a conventional copper/gold porphyry flowsheet, incorporating two stages of crushing and ball milling, followed by rougher flotation, concentrate regrinding and cleaner flotation to produce a pulp containing the final concentrate. A gravity circuit will be incorporated into the grinding circuit. The concentrate will be dewatered by thickening and filtration and loaded into trucks for delivery to Port of Stewart from where it will be shipped to smelters located in the Far East.

The ROM material from Donnelly Pit will be tipped onto a production grizzley that reports direct to a rasebored muckpass. The tipped material reports to a second grizzley located at the bottom of the muckpass where the ROM material will be screened prior to primary crushing: oversize will be fed to a gyratory crusher; while undersize and the gyratory crusher product will be conveyed to a coarse ore stockpile with a 24 hour live capacity.

Material will be withdrawn from the stockpile through one of a series of feeders, then conveyed to a double deck screen, the lower deck of which will have 25 mm apertures:
* screen oversize will be fed to a secondary (cone) crusher for crushing to 25 mm, from where it will be returned to the screen;
* screen undersize will be fed to a fine ore storage bin; and
* material from the bin will be conveyed to a ball mill for primary grinding.

Lime will be added to the ball mill feed to condition the pyrite and to aid its depression in downstream copper flotation circuits. The ball mill will operate in closed circuit with hydrocyclones. Hydrocyclone underflow will be returned to the ball mill, while overflow will be delivered to copper rougher flotation. A gravity unit will be installed on a 20% bleed from the ball mill cyclone underflow to capture coarse gold trapped in the circuit. Potassium amyl xanthate will be added to the cyclone overflow.

The gravity concentrate will be collected and upgraded (using a shaking table) to refinery grade, and will be sold directly to refineries. Tailings from the shaking table will be delivered to the copper concentrate thickener.

Copper rougher flotation will be carried out using 5 x 130 m3 conventional tank cells. The copper/gold concentrate produced from copper rougher flotation will be delivered to regrind cyclones. Underflow from the cyclones will gravitate to a vertimill, the product from which will be recycled to the regrind cyclones. Overflow from the hydrocyclones, sized at P80 20 microns, will be delivered to a bank of 50 m3 cleaner cells. Concentrate from these cleaner cells will be further cleaned using a flotation column. Tailings from the column will be scavenged using a bank of 25 m3 mechanically agitated column scavenger cells, with the concentrate circulated back to the column feed. Column scavenger tails will be circulated to the regrind cyclone feed pump box.

The ROM material from Spectrum Pit will trucked from the bottom of the Spectrum muckpass system to the MIA where it will be dumped on a coarse material pad from where it will be lifted and belt fed onto the coarse stockpile, where it will be blended with ROM material from Donnelly Pit. Material from the Donnelly Pit will be crushed using the 54” x 75” gyratory crusher installed for Stage 1, and then delivered to the coarse stockpile. Blended Spectrum-Donnelly ROM material will be fed from the coarse stockpile into a primary SAG mill. Product from the mill will be screened, with screen oversize (pebbles) returned by conveyor to the SAG mill feed. Screen undersize will be pumped to the ball mill cyclone feed pumpbox.

The ball milling, gravity recovery and copper flotation circuit will be the same as in Stage 1, but with extra flotation capacity added as needed to ensure provision of the necessary flotation residence time.

Copper flotation is largely unchanged from Stage 1, but the copper rougher tails will be subjected to a desulphurization pyrite float. Concentrate from this float will be combined with the copper first cleaner tails were it will be thickened to 55% solids, and then cyanide leached with carbon through a leach circuit with short residence time (12 hours). A regrind mill has not been included on the leach feed as the beneficial effect of regrinding has not been fully established. Cyanide will be added in the first four hours of the leach, but its concentration will be allowed to drop through the last eight hours. In addition, an SO2/air cyanide detox circuit will be installed to ensure the leach residue contains negligible free cyanide. The activated carbon from the leach circuit, loaded with gold and silver, will be stripped and regenerated through a conventional carbon handling circuit including elution and regeneration, electrowinning of the precious metals, calcining in an oven and, finally, smelting into doré. A small Acacia refinery package has also been included, which will process the gravity concentrate, so allowing the precious metals to be delivered to the refinery for conversion to doré.

Stage 2 (20,000 tpd)
During Stage 2, the plant will process a total of 20,000 tpd of a blended feed from the Spectrum and Donnelly Pits.

The ROM material from Spectrum Pit will trucked from the bottom of the Spectrum muckpass system to the MIA where it will be dumped on a coarse material pad from where it will be lifted and belt fed onto the coarse stockpile, where it will be blended with ROM material from Donnelly Pit. Material from the Donnelly Pit will be crushed using the 54” x 75” gyratory crusher installed for Stage 1, and then delivered to the coarse stockpile. Blended Spectrum-Donnelly ROM material will be fed from the coarse stockpile into a primary SAG mill. Product from the mill will be screened, with screen oversize (pebbles) returned by conveyor to the SAG mill feed. Screen undersize will be pumped to the ball mill cyclone feed pumpbox.

The ball milling, gravity recovery and copper flotation circuit will be the same as in Stage 1, but with extra flotation capacity added as needed to ensure provision of the necessary flotation residence time.

Copper flotation is largely unchanged from Stage 1, but the copper rougher tails will be subjected to a desulphurization pyrite float. Concentrate from this float will be combined with the copper first cleaner tails were it will be thickened to 55% solids, and then cyanide leached with carbon through a leach circuit with short residence time (12 hours). A regrind mill has not been included on the leach feed as the beneficial effect of regrinding has not been fully established. Cyanide will be added in the first four hours of the leach, but its concentration will be allowed to drop through the last eight hours. In addition, an SO2/air cyanide detox circuit will be installed to ensure the leach residue contains negligible free cyanide. The activated carbon from the leach circuit, loaded with gold and silver, will be stripped and regenerated through a conventional carbon handling circuit including elution and regeneration, electrowinning of the precious metals, calcining in an oven and, finally, smelting into doré. A small Acacia refinery package has also been included, which will process the gravity concentrate, so allowing the precious metals to be delivered to the refinery for conversion to doré.

Stage 3 will operate at 30,000 tpd, with 100% of the feed coming from the Donnelly Pit. The cone crusher used for secondary crushing in Stage 1 will be re-assigned for pebble crushing duty so enhancing SAG mill capacity. Additional grinding and flotation capacity will be added as needed.