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.

The potential to develop a large tonnage, open pit resource at Touquoy was recognised in 1986 1987 when drilling around old workings at Moose River Gold Mines intersected wide intervals of relatively low grade gold mineralization.

It is this disseminated style of gold mineralization, localised in an anticlinal fold hinge and attended by a relatively small proportion of gold mineralised bedding-parallel quartz veining, which is the focus of the on going development of the Touquoy Gold Deposit.

At Touquoy, by far the largest concentration of gold on the Touquoy Property, the bulk of the gold mineralization, including disseminated mineralization, occurs within the Touquoy Argillite. Gold mineralization in the greywackes, particularly the coarser grained greywackes is mostly restricted to Meguma style, narrow quartz vein hosted gold mineralization. However, both styles of gold mineralization also occur within the mixed argillite and greywacke sequence (Quarry Belt to Higgins Greywacke) overlying the Touquoy Argillite on the northern limb of the anticline. Disseminated and vein-hosted styles are superimposed over the length of the deposit – some 600 m – but at the western end of the deposit, thick sequences (~100 m) of less variable grade gold mineralization predominate while narrower widths (10-20 m) of marginally higher grades become more apparent to the east.

The Touquoy host rocks have been metamorphosed to lower greenschist facies. Detrital minerals, including quartz, feldspar and muscovite, are preserved in the coarser grained (greywacke) lithologies but are largely replaced by metamorphic minerals in the finer grained (siltstone and claystone) lithologies such that the dominant mineral assemblage in the argillites is quartz, muscovite and chlorite +/- albite with accessory illmenite and rutile.

Sulphide minerals accompanying the gold mineralization are pyrrhotite, usually aligned along the axial plane cleavage (1-2%), arsenopyrite, often as coarse porphyroblasts (1%) and pyrite (<1%). Other sulphides are rare. At a macro scale there is poor correlation between arsenic and gold content.

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.

Touquoy Phase 1, West Phase.
This pit targets the west portion of the Touquoy deposit, which contains higher grade gold than the east portion. This phase contains about 3 years’ worth of mill feed. This phase mines from the pit exit at the 115 m elevation, down to the pit bottom at the -25 m elevation. The ramp runs counter-clockwise down from the 115 m pit exit in the north end of the pit, and switchbacks at the 35 m, 10 m and -5 m bench elevations.

Touquoy Phase 2, East Phase.
This phase targets the remaining east portion of the deposit and contains about 1.5 years’ worth of mill feed. It mines from the pit exit at the 125 m elevation, down to the pit bottom at the 50 m elevation. The ramp runs clockwise down from the 125 m pit exit in the south of the pit. Three separate pit bottoms are defined below the 90 m elevation; each is accessed through spurs off of the main ramp at the 90 m bench elevation.

The Touquoy operations require two 4.5 m3 bucket hydraulic excavators and one 7.0 m3 bucket front end wheel loader, which are sized to match the 64 tonne payload haulers and to meet the production requirements of the mining schedule.

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.

The Touquoy process plant is designed for an ore treatment of 2 Mt/a or 250 t/h based on an availability of 8,000 h/a, or 91.3%. However, the crushing section design is set at 60% availability since it operates outdoors and uses modular semi- mobile equipment. It will accept Touquoy ROM ore for the first five years of operation and thereafter ROM ore from the Beaver Dam deposit at the same treatment rate using the same unit operations. Only relatively minor equipment modifications are expected to be needed at Touquoy to treat the Beaver Dam ore.

The main plant building houses the grinding, gravity recovery, reagent, elution and refinery sections. The crushing and CIL sections are located outdoors. The three-stage crushing circuit ahead of a single-stage ball mill is based on modular semi-mobile crushing equipment so as to allow the modifications necessary to allow the introduction of Beaver Dam ore.

ROM is hauled from the Touquoy pit to the primary crusher and tipped over a static grizzly sloped to bring oversize back to the loading side for removal by a front-end wheel loader (FEL). The FEL supplements the direct-tip feed from the Touquoy ROM stockpiles to maintain a continuous crushing operation. Mine operations retrieve any oversize and either use a mobile rock breaker to reduce the lump size or return oversize to the pit.

The mobile crushing plant produces a fine ore sized to a P80 of 10 mm. The throughput of the crushing plant package is 381 t/h at a crushing plant availability of 60%.

The fine ore product is conveyed to a fine ore stockpile (12,000 t capacity; live volume of 3,000 t). Two variable-speed reclaim slot belt feeders provide two live pockets and an estimated 25% natural reclaim of the stockpile. The fine ore feed to the mill is conveyed by a 95 m long covered mill feed conveyor from the two fine ore reclaim feeders to the mill feed chute.

The 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.

Mill slurry discharge overflows onto a rubber- lined trommel screen with trommel oversize discharging to a bunker for regular collection and disposal. The trommel undersize gravitates to the cyclone feed hopper where the slurry is diluted with process water and pumped with a duty/standby cyclone feed pump to the cyclone cluster. A density meter monitors and controls the amount of process water required to produce a target density to the cyclones.

The cyclone underflow splits, with up to 30% feeding the gravity circuit and the remaining underflow stream gravitating to the ball mill. The cyclone produces a fine ground overflow product of P80 150 µm which is sampled, and then gravitates to the vibrating trash screen. Oversize debris are removed and falls to a trash bin at ground level. The minus 0.8 mm trash screen underflow flows by gravity to the CIL circuit.

A portion of the ball mill circulating load is fed into two 50% 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 intensive cyanidation circuit receives the periodic gold concentrate for treatment in an intensive leach reactor. The gold-containing pregnant solution is pumped periodically to a dedicated eluate tank in the gold room.

The trash screen underflow enters the pre-leach feedwell after mixing with metered flocculant. The feed box slurry gravitates to the leach tank and optionally can feed directly to CIL Tank 1.

The circuit is a hybrid CIL type and consist of one leach tank and six adsorption tanks in series, each having a live volume of 1,169 m3. The design allows for a 250 t/h solids feed rate at 50% solids for an average 24-hour residence time. Each tank is interconnected with launders to allow slurry to flow sequentially by gravity to each tank in the train.

Barren carbon enters the adsorption circuit at CIL Tank 6. The carbon advances countercurrent to the main slurry flow during periodic transfers of slurry and carbon using air lift movement from a downstream to upstream tank. Carbon concentrations of 10 to 15 g/L are required in all tanks. Carbon is retained in the upstream tank by an intertank screen. The countercurrent process is repeated until the carbon becomes loaded and reaches CIL Tank 1. Then a recessed impeller pump transfers slurry and carbon to a loaded carbon recovery screen. The loaded carbon is washed with water and released to the acid wash column located inside the main plant, in the desorption area. The slurry returns to CIL Tank 1.

Following elution of the loaded carbon and thermal regeneration, the barren carbon is screened and reported to CIL Tank 6. Fine carbon is discarded to the CIL tailings hopper.

The pressure Zadra elution circuit (elution column, strip solution tank, strip solution pump and a strip solution heater package) operates in a closed loop with the electrowinning cells located inside the gold room.

Three electrowinning sludging cells are used; one cell is dedicated to the intensive cyanidation circuit and the other two cells to the elution circuit.