The Kiena Mine Complex area is located in northwestern Quebec, straddling the southern part of the Abitibi greenstone belt (AGB) and the northern part of the Pontiac Subprovince:
- The AGB comprises E-trending successions of folded and faulted volcanic and sedimentary rocks and intervening domes of intrusive rocks. An important geologic feature of the AGB is the occurrence of major, E-trending ductile-brittle fault zones. These zones cut across the entire belt from the Kapuskasing structural zone in the west to the Grenville front in the east, dividing the supracrustal rocks and intervening domes into distinct lozenge-shaped domains. The most two important fault zones in the southern AGB are Destor-Porcupine fault zone (DPFZ) in the north and Larder Lake-Cadillac fault zone (LLCFZ) in the south.
- The Pontiac Subprovince (PS) consists principally of a turbiditic succession composed of graywacke and mudstone with minor intercalated conglomerate and basalt.

The Kiena Complex area has a series of large-scale shear zones and related subsidiary faults trending ESE-WNW to SE-NW, subparallel to stratigraphy and dipping steeply to the north. They are, from south to north: the Larder Lake-Cadillac Fault Zone (LLCFZ), the Parfouru Fault (PF), the Marbenite Fault (MF), the Norbenite Fault (NF), the Callahan Fault (CF), the K Shear Zone (KSZ) and the Rivière Héva Fault (RHF). The Kiena Complex area is cut by all of them. The shear zones contain dykes or stocks of monzonitic or tonalitic composition that vary widely in age (pre-, syn- or post-tectonic) and are spatially associated with gold mines (Norlartic, Marban, Kiena, Sullivan, Goldex, Siscoe, Joubi, Sigma and Lamaque). The observed diversity in the styles and ages of gold mineralization related to these large-scale shear zones demonstrates that several distinct episodes of mineralization occurred.

Gold mineralization on the Kiena Mine Complex shares many geological attributes with other vein-type gold deposits of the Val-d’Or district and with orogenic gold deposits (also known as lode gold, greenstone-hosted quartz-carbonate vein, or mesothermal deposits) in terms of host rock composition, mineralogy and hydrothermal alteration.

Gold mineralization in the property occurs in all rock types except the Proterozoic dykes but is more common in intrusive bodies and basalt as these acted as competent rock units that promoted fracturing during deformation. Gold mineralization is concentrated where there is a marked competency contrast between these competent units and the adjacent deformed komatiite and/or chlorite-talc schists. There are at least two main gold mineralizing events in the region: young deposits in which the gold mineralization did not experience much deformation after its emplacement; and early mineralization in which mineralized bodies are commonly affected by D1 asymmetric folds, are highly strained and are locally dismembered. In a few deposits, both generations are present. Gold-bearing veins in the region exhibit a great variety of orientations, mineralogy and crosscutting relationships.

At least 63 mineralized zones have been observed on the property. In general, mineralized zones on the property occur near a large-scale fault. They are often associated with a subsidiary shear zone that may be proximal, adjacent or host to the mineralization. Alteration minerals are dominantly albite, carbonates and pyrite with lesser chlorite and silica.

The presence in the same area of more than three types of gold-bearing veins exhibiting a wide range of orientations, mineralogy and crosscutting relationships, and the fact that several generations of dykes and veins are involved, suggests that gold mineralization was the product of multiple mineralizing phases (Beausoleil et al., 2019).

Most of the production mining will utilize the overhand long hole stope method, historically used at the Kiena Mine Complex. In cases where production mining is expected under previously mined and backfilled stopes, the underhand long hole stope method will be utilized.

Long hole production stopes will be mined on a longitudinal retreat basis. Stope empirical designs and mine sequencing were established for each of the three mining zones accounting for key factors influencing stability including rock mass quality, the orientation of the principal structures, in situ stress and the geometry of the stope. Cemented rockfill, rockfill and paste backfill were considered for supporting the rock mass after extraction. Mining recovery will be maximized and production stope cycle time optimized in the Kiena Deep A Zone by making paste backfill the predominant backfill type.

Both existing and new infrastructure are required to support the LOM plan. The key existing infrastructure includes the hoisting shaft extending to a depth of 930 m with an average hoisting capacity of 2,000 tpd, ore and waste pass systems, the underground crusher, underground ventilation raise and ramp system, service repair, fueling, refuge, process water, mine dewatering, compressed air and electrical facilities.

Haulage trucks and load haul dumps (LHD) are currently owned and operated by a contracted mining company for ore and waste rock haulage. Most other mobile equipment is also currently owned and operated by the mining contractor. In 2021, it is intended that the Kiena Mine Complex will begin purchasing and operating their own heavy haulage mobile equipment as well as all other mobile equipment to support the LOM plan.

Expected performance underground was influential in Wesdome Kiena Mine Complex deciding to proceed with paste backfill.

The crushing circuit is fed by 150 mm rock coming from the Birdsboro Buchanan jaw-crusher located underground. The ore is hoisted to surface and stored in two raw ore silos, each capable of holding 600 t. Vibrating feeders under the silos reclaim the ore and feed it to a diverter chute that either feeds the secondary crushing circuit or the crushed ore silo conveyor that leads to the crushed ore silo that can hold 1,800 t. The secondary crushing circuit is composed of a feed conveyor, a screen, a standard cone crusher and product conveyors. With the current production plan, the secondary crusher is not required and will be bypassed.

The mineralized material is ground in a semi-autogenous grinding (SAG) mill operating in an open circuit, followed by a ball mill operating in closed circuit with two stages of classification cyclones.

Cyanide and lead nitrate are added at the SAG mill along with milk of lime. The underflow of the primary and secondary cyclones is redirected to the ball mill for further grinding. The cyclone overflow is then pumped to a vibrating trash screen. The screen undersize is directed to the preleach thickener and the oversize is pumped with water to the tailings pump box. The pulp from the thickener underflow is transferred to the leaching circuit while the thickener overflow is partially pumped to a series of three carbon columns to adsorb the gold in solution. The last carbon column in the series overflows onto a safety carbon screen where the oversize carbon that would mistakenly escape from the column is sent to the second CIP tank. Once every two days, the loaded carbon of the first column is sent to the loaded carbon screen, the carbon from the downstream columns is transferred to their respective upstream column and unloaded carbon is added in the last column. The third column discharge screen undersize reports to the grinding solution tank along with the remainder of the thickener overflow. The grinding solution is recycled back to the grinding circuit as grinding solution.

The Kiena Mine Complex was designed for a throughput of 1,250 tpd, and up to 2,000 tpd once crushing capacity was added.

The restart, aiming at processing 1,000 tpd of mineralized material from the Kiena Deep deposit along with material from S50 and Martin zones will be done using the existing Kiena concentrator with minor modifications.

The principal process steps will include grinding, cyanide leaching, gold adsorption and desorption on activated carbon, electrolysis and cyanide destruction.

Cyanide and lead nitrate are added at the SAG mill along with milk of lime. The underflow of the primary and secondary cyclones is redirected to the ball mill for further grinding. The cyclone overflow is then pumped to a vibrating trash screen. The screen undersize is directed to the preleach thickener and the oversize is pumped with water to the tailings pump box. The pulp from the thickener underflow is transferred to the leaching circuit while the thickener ov ........