Historic gold mining in Nova Scotia, including mining in the Moose River Gold District, has focussed on quartz-vein hosted gold deposits within the Goldenville Formation, typically associated with the limbs and hinges of anticlines. This setting is often referred to as ‘Meguma style’ gold mineralization.

In recent years the existence of disseminated gold mineralization and potential to develop large tonnage, open-pitable resources in Nova Scotia has been recognised, particularly since 1986-87 when drilling around old workings at Moose River Gold Mines intersected wide intervals of relatively low grade gold mineralization in what is now known as the Touquoy gold deposit. Since then, disseminated gold mineralization has been identified at a number of locations, spatially associated with anticlinal fold hinges. Most of that mineralization is associated with argillites or mixed greywacke-argillite units within the Goldenville Formation, including Touquoy, Beaver Dam and Fifteen Mile Stream; however, disseminated gold has also been recognised in greywacke host rocks within the Goldenville Group at North Brookfield and several other sites.

At Beaver Dam the highest gold grades are typically associated with bedding-parallel tabular quartz veins localised on the southern limb near the hinge zone of the Moose River Fifteen Mile Stream Anticline. However, the host rock material between quartz veins also carries significant gold grades. It is the quartz vein hosted gold mineralization augmented by disseminated style mineralization that forms the basis of a geological model associated with the ongoing exploration and development of the Beaver Dam gold deposit.

Gold mineralization at Beaver Dam has been recognised over a strike length of approximately 1.4 km, extending from the Main Zone northwest to the Mill Shaft Zone. Historic drilling has shown that mineralization weakens between the Main Zone and Mill Shaft Zone and detailed drilling by Acadian is limited to a section approximately 800 m in length in the Main Zone. The eastern end of the main zone is controlled by the Mud Lake Fault and possible offsets to the mineralization have been identified between the Mud Lake and Cameron Flowage faults and in the Northeast Zone, immediately east of the Cameron Flowage Fault.

The gold mineralization at Beaver Dam occurs both within quartz veins and within the argillite and greywacke host rocks. The quartz veins that host gold mineralization are more commonly bedding parallel but also include cross-cutting veins. Quartz veins are generally in the range of 0.5 cm to 20 cm thickness and frequently include sulphides, particularly pyrrhotite, pyrite and/or arsenopyrite with lesser chalcopyrite, galena or sphalerite. Gold commonly occurs within quartz veins as coarse (>1 mm) grains and clusters of finer (<1 mm), but still visible grains. Coarse gold grains are more likely to be found at vein-wall rock contacts and are often spatially associated with sulphides.

Anomalous gold grades in the 0.1 g/t to 4 g/t range have been returned for intervals with no quartz veins or visible gold. This argillite and greywacke hosted (or disseminated) gold mineralization is often associated with sulphides including pyrrhotite, pyrite, arsenopyrite and chalcopyrite.

Mining is based on conventional open pit methods suited for the project location and local site requirements.

Mine operations are anticipated to begin at Touquoy, and move to Beaver Dam once the Touquoy pit reserves are exhausted in year 5.

B621 targets the south portion of the deposit, which contains a higher grade gold and lower strip ratio than the north portion. This phase contains about 1.5 years’ worth of mill feed and mines from the pit exit at the 130 m elevation, down to the pit bottom at the 45 m elevation. The ramp runs counter-clockwise down from the 130 m pit exit in the east of the pit and switchbacks at the 85 m bench elevation.

B622 pushes the north and east wall to the ultimate limits and extends the bottom of the pit below the first pit phase. This phase contains about 1.5 years’ worth of mill feed and mines from the pit exit at the 130 m elevation, down to the pit bottom at the -45 m elevation. The ramp runs counter-clockwise down from the 130 m pit exit in the east of the pit.

The Beaver Dam operations require an additional two excavators and one wheel loader.

The hydraulic excavators are specified to handle the bulk of excavation from the pits, including all identified mineralized zones and the waste rock in those mineralized zones. The wheel loader is specified for mining waste only areas of the pit, re-handling stockpiled material, pit clean up, road construction and snow removal. Blasted patterns will be mined on 5 m or 2.5 m split benches in all mineralized zones, depending on grade control requirements and on 10 m benches or 5 m half benches in all gold barren areas.

The excavator size is chosen based on its ability to minimize losses and dilution for the proposed ore control operations, as well as its proven reliability and relatively large population. It can work effectively on 2.5 m or 5 m split bench heights and can be utilized on full 10 m benches.

The wheel loader is chosen based on its ability to load the truck in 4-6 passes, which is an efficient target for bench face loading scenarios, as well as its proven reliability and relatively large population. The wheel loader is also sized as appropriate for feeding the crusher when required.

Ore and waste rock haulage will be handled by off-highway rigid frame haul trucks with a 64 tonne payload. Haulage profiles are estimated from pit centroids at each bench to designated dumping points for each scheduled time period. The following hauler productivity parameters are applied to calculate the cycle times.

At Beaver Dam, ore will be hauled to a crusher that will be located 600 m south of the pit, and then crushed ore will be hauled by on-highway haulers from Beaver Dam to the process plant at Touquoy operations.

The Touquoy process plant is designed for an ore treatment of 2,000,000 t/y or 250 t/h based on an availability of 8000 h/y, or 91.3%. However the crushing section design is set at 60% availability since it operates outdoors and utilizes modular mobile equipment. It will accept Touquoy ore for the first five years of operation and thereafter ore from the Beaver Dam deposit at the same treatment rate using the same unit operations. Only relatively minor equipment modifications are needed at Touquoy to treat the harder Beaver Dam ore with a higher abrasion index. These factors have been considered in the design of the ball mill equipment and operating costs.

The proposed flow sheet uses conventional processes for:
- Crushing.
- Grinding.
- Gravity recovery.
- Carbon-in-leach (CIL).
- Desorption/Electrowinning/Refining.
- Tailings management and cyanide destruction.

A mobile three stage crushing unit has been selected for the Moose River project ahead of a single stage ball mill. The crushing plant produces a fine ore sized to a P80 of 10 mm. The throughput of the crushing plant package is 5479 t/d or 381 t/h at 60% crushing plant availability. The jaw crusher and grizzly feeder will be relocated from the Touquoy plant to the Beaver Dam mine prior to Beaver Dam ore being processed.

A new simple satellite primary crushing facility consisting of a grizzly feeder, jaw crusher and primary coarse ore stockpile feed conveyor will be required at Beaver Dam fed from a ROM stockpile or direct dump from the mine fleet. This facility will be ready to operate by the time the Touquoy ore is depleted. The crushing circuit has been configured to minimize the transition period for equipment changeover, adopting modular components where practical.

At the transition to Beaver Dam ore processing starting in Year 6, most of the Touquoy crushing circuit will remain unchanged. The following outlines the physical changes required to accommodate the Beaver Dam ore at the Touquoy process plant:
- The primary jaw crusher module will be relocated from the Touquoy location and installed at the Beaver Dam crushing station before Year 6. A coarse ore stockpile feed conveyor will be installed at Beaver Dam along with a new ROM hopper at the crusher station. The remaining secondary and tertiary sections of the Touquoy crushing plant along with the FOS will remain in place unaltered.
- The vibrating feeder at Touquoy will be removed and replaced by a new vibrating pan feeder. The grizzly feeder at Touquoy will be relocated to the Beaver Dam crushing station.
- A new ROM hopper and grizzly identical in size to Touquoy will be installed at Beaver Dam crushing station and the used Touquoy equipment will be fitted.
- The primary crushed ore from Beaver Dam will enter the Touquoy secondary crushing circuit through the existing ROM hopper. A new vibrating feeder and new collection conveyor will be fitted to tie-in to the existing secondary feed conveyor. The downstream equipment will remain unchanged.
- The existing Touquoy ROM hopper and grizzly will provide the direct tip feed point to the main plant for the Beaver Dam ore. The FEL used for the first 5 years of operation to load the ROM will continue to load Beaver Dam ore that is not direct tipped.

Primary crushing at Beaver Dam will provide a primary crushed ore stockpile with two days live volume equivalent to 11,000 t capacity. This stockpile inventory will buffer a commercial ore transport road truck fleet hauling the primary crushed ore to the feed point of the main plant. A fleet of 22 trucks each having a nominal payload of 31 t and requiring 9 cycles per day/truck will deliver the daily tonnage requirement to meet the Touquoy mill demand.

Haul trucks will provide daily ore transport between the Beaver Dam coarse ore stockpile and Touquoy plant. One way hauling distance is approximately 37 km. The main plant will undergo minor retrofits between the Touquoy ROM hopper and secondary crushing section to receive the primary crushed ore.

Also prior to year six, at the back end of the process plant, the tailings line will be re routed to the old Touquoy pit once the Touquoy mining operation has shut down. The reclaim water pump and barge, with a rerouted pipeline to the process water tank, will be later relocated from the TMF to the old Touquoy pit when water accumulation level is adequate in the pit.

The Ball Mill is sized to handle both the Touquoy and Beaver Dam ores without any mechanical adjustment required during the transition between mines. The Touquoy ore is expected to operate at a lower ball volume and steel ball consumption than Beaver Dam ore to compensate for the difference in hardness and abrasion characteristics.

The Touquoy process plant provides indoor space for grinding, gravity concentration and intensive cyanidation, desorption and regeneration, refinery and reagents areas. It also houses plant offices, electrical rooms and a control room. The CIL circuit, preleach thickener, cyanide detoxification tanks and water services tanks are located outdoors in close proximity to the process plant. The reagent storage, warehouse, assay laboratory structures are located within about 55 m of the process plant. Propane storage and the main electrical substation areas are located to the west of the plant area. An air services building is adjacent to the CIL tank area and a water services pump-house is positioned with the water tanks.

Based on testwork results the Beaver Dam ore is harder and has a BWi of 15.3 kWh/t whereas the Touquoy ore is lower at 9.4 kWh/t.

The F80 10 mm mill feed is processed through one single pinion 4.9 m x 8.1 m ball mill in closed circuit with hydrocyclones producing a final product of P80 150µ. The mill has a nominal solids throughput of 5479 t/d and can process 250 t/h at 91.3% availability. The overall ball mill circulating load is 250%.

The mill is sized to handle both the Touquoy and Beaver Dam ores without any mechanical adjustment required during the transition between mines.

A portion of the ball mill circulating load is split and fed into two duty/duty parallel gravity concentrator trains. The gold concentrate recovered is treated in an intensive batch leach system designed to handle 2.4 t/d of concentrate. The resulting concentrated gold solution is pumped to a dedicated eluate tank at the gold room.

The trash screen underflow is increased from 35 to 50% solids in the 18 m diameter high rate pre-leach thickener in preparation for the CIL step.

The leach feed from the thickener underflow is pumped to a linear primary CIL feed sampler. A secondary rotary vezin cutter provides a representative CIL feed sample before entering the leach feed box. The leach feed slurry is subsequently mixed with lime slurry in the leach feed box to raise the slurry pH for cyanide gold extraction. The feed box gravitates to the leach tank and optionally can feed directly to CIL Tank 1.

The circuit is a hybrid CIL type and consists of one leach tank and six adsorption tanks in series, each having a live volume of 1169 m3. The design allows for a 250 t/h solids feed rate at 50% solids for an average 24 hour residence time.