Gold deposits in the Hardrock deposit area are classic examples of epigenetic non-stratiform BIF-hosted gold deposits (historical North Zone and West Zone). Gold mineralization has resulted from the introduction of hydrothermal fluids in zones of high crustal permeability. Most mineralized occurrences in the Hardrock deposit area lie in a zone of deformation to the immediate north of, and genetically linked to, the Tombill-Bankfield Deformation Zone. Numerous Z-folds on various scales were formed in the deformation zone. Auriferous vein systems in the MacLeod-Cockshutt and Hard Rock mines are hosted by one of the Z-folds. This structure plunges shallowly west and is mimicked by minor parasitic folds in the BIF. The mineralization is found in upright sub-vertical axial planes that trend roughly east-west. The fold axes are shallowly west-plunging.

Two main styles of mineralization at the Hardrock deposit are quartz-carbonate stringer mineralization and sulfide replacement mineralization. Quartz-carbonate stringer mineralization generally consists of a series of narrow, tightly asymmetrically folded gold-bearing quartz-carbonate stringers, which are usually attenuated, transposed and dislocated in hook-like segments. The stringers are accompanied by a gold-bearing quartz-sericite-pyrite (±arsenopyrite) alteration halo about the stringers. Sulfide replacement mineralization occurs as variable pyrite, arsenopyrite and pyrrhotite replacement of Fe oxide within the hinge zones of folded BIFs. The auriferous sulfide replacement appears to have migrated outwards along the iron oxide bands from gold-bearing quartz-carbonate stringers occupying brittle axial planar tension fractures; this replacement mineralization yields grades of 7 g Au/t or greater.

Mining will be carried out using conventional open pit techniques with 10 m benches. An Owner mining open pit operation is planned with hydraulic shovels and mining trucks and includes outsourcing of certain support activities such as explosives manufacturing and blasting.

Production drilling of the 10 m benches will be by blast hole drill rigs with both rotary and down-the-hole (“DTH”) drilling capability. Blast holes are loaded with bulk emulsion. The majority of the loading in the pit will be carried out by three hydraulic face shovels, two 26 m3 and one 19 m3 and two front-end wheel loaders (21 m3). The shovels and loaders will be matched with a fleet of 181 t payload mine trucks. The presence of underground stopes was considered when designing the pits mainly for the void in the F-Zone, which is 150 m high and 30 m wide. Most of the other underground openings are backfilled with sand fill or rock fill.

Mining of the Hardrock main pit will occur in four phases (including the borrow pit) with a single phase for the smaller satellite pit to the east. Waste rock will be disposed of in four distinct waste dumps with three located around the pit and one further to the south. The open pit generates 548.9 Mt of overburden and waste rock (inclusive of historic tailings and underground backfill) over the life of mine (“LOM”) for an average LOM strip ratio of 3.87:1.

The LOM plan details 14.5 years of production, with a four month ramp up and commissioning period, followed by eighteen (18) months at a processing rate of 24,000 t/d ore, increasing to 27,000 t/d ore for the remainder of the mine life.

The gold recovery process for the Hardrock Project consists of a crushing circuit (gyratory and cone), a grinding circuit HPGR and ball mill, pre leach thickening, a leach and carbon-in-pulp (“CIP”) circuit, cyanide destruction and tailings disposal, carbon elution and electrowinning, carbon regeneration and a gold refinery.

The crushing plant is a two-stage circuit consisting of a primary gyratory crusher and a secondary cone crusher. The crushing plant is expected to operate 67% of the time in order to achieve the daily throughput. A 30% design factor has been selected for the crushing circuit equipment so that the conveyors, crushers and other crushing equipment are sized to handle up to 2,194 t/h.

The run-of-mine ore is delivered by mine haulage trucks or by loader to the crushing plant. The ore is dumped into a 300 m3 concrete receiving hopper that feeds the primary crusher. A rock breaker will be used to break oversized rocks. The 652 kW gyratory crusher crushes the ore from a 1,000 mm top size (275 mm P80) to an 80% passing 123 mm product. The crushed ore falls into a concrete hopper and is reclaimed via an apron feeder. A sacrificial conveyor is installed before the secondary crushing feed conveyor which feeds the secondary crusher feed bin.

The cone crusher feed is controlled by an apron feeder. The secondary crusher is a 933 kW standard cone with a 55 mm closed side setting (“CSS”). The secondary cone crusher is installed in closed-circuit with a single deck screen. This arrangement is preferred in order to control the top size feeding the high pressure grinding rolls. The screen oversize is returned to the secondary crushing feed conveyor. With a 69 mm closing screen opening, the crushing circuit produces a final crushed product with a 55 mm top size and a 42 mm P80.

The crushing circuit product is stored in a 27,550 t live capacity stockpile (78,000 t dead capacity). The stockpile is located between the secondary crushing plant and the process plant. A single stockpile reclaiming line is planned; three apron feeders are located in a tunnel underneath the stockpile. These apron feeders feed a grinding feed conveyor which discharges onto the HPGR feed bin located inside the HPGR building. If required, the material can also be diverted to a bunker/pad. Insertable dust collectors are installed in the transfer chutes between the apron feeders and the HPGR feed bin.

The grinding and gravity circuit consists of one operating line made up of a HPGR, two ball mills, a cycloning stage and two gravity concentrators. The gravity products from both concentrators are combined in a single gravity concentrate leaching unit.

A detailed comminution trade-off study recommended a two stage crushing followed by HPGR and ball milling circuit over other typical comminution flowsheets such as crushing followed by semi-autogenous (“SAG”) milling and ball milling, for the reasons of reduced risk in meeting the design throughput, and increased energy efficiency.

The HPGR screened product is discharged to the ball mill pump box. The pump box is equipped with two sets of two slurry pumps (one operating and one on stand-by): one set feeding the ball mill cyclones and one set feeding the gravity circuit. Approximately 60% of the fresh feed is diverted to the gravity circuit.

The gravity feed pump transfers a portion of the ball mill pump box content to the gravity circuit to recover gravity recoverable gold. One gravity screen and two gravity concentrators are installed to process the material.

The gravity concentrate from both gravity concentrators is transferred to the single gravity concentrate leaching circuit. This system is a packaged unit consisting of a feed tank, a drum leach reactor, a solution storage tank and a transfer pump.

The circuit is made up of a pre-leach thickener, a series of leach tanks (one pre-leach and five leach tanks) followed by seven CIP tanks. The objective of the pre-leach, leach and CIP circuit is to dissolve gold from the ground ore, adsorb it onto activated carbon and transfer the loaded carbon to the elution circuit.

The leach circuit consists of one agitated pre leach tank and five agitated leach tanks. The leach tanks are located outdoors. The slurry transfers from one tank to the next by overflow through an upcomer. Any tank can be bypassed if maintenance is necessary. The leach tanks are equipped with 220 kW agitators. The total residence time in the leach circuit is 36 hours and an additional seven hours is available in the pre-leach tank.

The leach circuit discharge falls into the CIP launder located above the CIP tanks. The circuit is composed of seven CIP tanks but the required 1.5 hours of residence time is achieved in six tanks. The seventh tank is included to ensure the residence time is maintained when one tank is not in operation. The CIP tanks are located indoors.

The cyanide destruction circuit consists of two agitated tanks. The tailings from the CIP circuit are pumped to the cyanide destruction distribution box and then to the first of the two cyanide destruction tanks. The cyanide destruction tanks are normally used in series but they can also be used in parallel if required.

The pregnant solution from the gravity concentrate leaching is pumped to its dedicated electrolyte tank located in the electrowinning area. The electrolyte solution is circulated between the gravity electrowinning cell and the electrolyte tank. The pregnant solution from the elution circuit is transferred to a flash tank prior to being split between four electrowinning cells.