The Houndé deposits are shear-zone hosted orogenic gold deposits as supported by occurrence of sulphide-gold mineralisation in deformed, quartz carbonate-sulphide(-gold) veined and strongly metasomatised greenstone wall rocks.

A strong, northeast-trending, dextral shear zone cuts through the Houndé area. This shear zone lies approximately three kilometres west of the Vindaloo Zone and has a very sharp western edge, as defined by the magnetic data. The eastern edge of the structure is not well defined; however, magnetic data suggests that the shear zone may be four to six kilometres wide. To the east of this strong structure, shearing is focused along unit contacts with preference along the sediment volcanic, volcanic-gabbro and sediment-gabbro contacts. Sediment units are often strongly deformed and display local graphitic shear zones, gouge and healed breccias.

Vindaloo-Madras
The Vindaloo and Madras mineralised zones are predominantly hosted by altered magnetitebearing gabbro and to a lesser extent, andesitic volcanic rocks and sediments. The gabbrohosted zones range up to 70m in true thickness and average close to 20m true thickness in a section of the zone called Vindaloo Main. Volcanic- and sediment-hosted zones are generally less than five metres wide. The mineralised system is zoned with initial propylitic-style alteration along the outer edges of the system with the addition of chlorite and calcite stringers concurrent with the destruction of pyroxene, amphibole and plagioclase. In a poorly defined area, located to the west of the Vindaloo Main zone, the propylitic alteration is overprinted by a reddish hematitic alteration comprising disseminated hematite and hematite veinlets. Fine grained to millimetre-size pyrite crystals are associated with:
• Trace to 10%, up to 2cm wide, quartz veins (trace to 2% overall in mineralised zones);
• Pyrite-enriched haloes to the quartz veins; and
• Occasionally as disseminations within the host gabbro.

Bouéré
Gold mineralisation at Bouéré is associated with hydrothermal alteration zones and related quartz-carbonate veining, that appear to have occurred in protracted fashion throughout D1 and D2 deformations. The hydrothermal alteration at Bouéré evolved through D1 carbonatization (associated with no or very low-grade mineralisation) towards sericitization and silicification which occurred in pulsative fashion at a transitory late-D1 to syn-D2 stage of deformation (associated with significant mineralisation). Gold mineralisation is coeval with a progressive increase in the D2 deformation and a variably intense sericite – silica - carbonate (ankerite + calcite) ± albite alteration and zones of quartz – carbonate veining, both associated with sulphides dissemination in the altered rocks and in quartz veins. Gold veins were emplaced during a continuum of deformation between late D1 and syn-D2. High to very high gold grades are systematically associated with massive and/or laminated milky quartz (± carbonate ± albite) veins from one metre to multiple metres thick occurring in the silica-sericite-carbonate-sulphide alteration zones. Visible gold is nearly exclusively seen in theses quartz veins. Bouéré is characterised with low continuity of mineralisation over short along-strike distances and relay-type patterns of mineralisation resulting in fragmented/discontinuous lenses of mineralisation.

Dohoun
Gold mineralisation at Dohoun is intimately related to the shear zone along the western edge of the granodioritic intrusive. The gold is hosted in a brittle-ductile context with mainly pyritictype sulphides. The pyrite grain geometry is highly variable, though gold is generally associated with fine- to medium-grained pyrite in a hydrothermal alteration halo of sericite and quartzcarbonate veins. Richer and thicker mineralisation have been observed in volcanic rocks in direct contact with the intrusive where the shear zone thickens; however, the portion of the shear zone crossing the intrusive is low to medium grade (<2g/t Au).

Kari Centre
Kari Centre gold mineralisation is developed mainly within the volcanics, associated with whitish sulphide-sericite-albite alteration and fine disseminated pyrite at the hanging wall of the volcanic/sediments contact (N60° strike, dipping 45° to the northwest). The mineralisation is diffuse, locally high grade (>2g/tAu) but generally lower grade when hosted in the oxide horizon. In brittle sedimentary units, gold grades are structurally controlled, and locally can be high grade (>5g/tAu). These mineralised zones tend to occur in narrow, tension gash type structures. To date, neither visible gold nor arsenopyrite have been observed in drill cuttings.

Kari Pump
Gold mineralisation occurs at Kari Pump within a sheared reverse fault (D2) that appears to be folded and dipping from zero to 40 degrees to the west-northwest and northwest. The mineralisation exhibits good continuity over 1.3km along section and displays typical pinch and swell characteristics. The highest-grade areas of the quartz veins are typically thicker, and alternate with thinner vein areas which are typically lower in grade. Kari Pump gold mineralisation is associated with the pyrite occurring as veinlets and disseminated grains within the silica altered and quartz vein bearing host shear.

Kari West
Kari West hosts multiple stacked mineralised lenses that are sub-parallel to the lithological foliation, reflecting both strong structural and lithological control. The mineralised lenses trend in a general west to west-southwest direction with shallow and moderate dips to the north. The lenses vary in thickness from a few metres to locally tens of metres, displaying pinch and swell characteristics both along strike and down dip; structural observations suggest that the thicker zones may represent the intersection of two mineralised lenses with varying dip and strike characteristics. The gold mineralisation in Kari West is associated with pyrite occurring as veinlets and disseminated grains within the quartz veins and SASE and SEAL alteration.

The mining method employed at Houndé Gold Mine is conventional open pit excavator-truck operation with the production unit operations (drilling, blasting, loading, hauling and dumping) carried out by mixed owner contractor mining personnel and equipment. Load and haul activities are owner operated and contract service providers, SFTP Mining and African Explosive Limited (“AEL”), carry out drilling and blasting activities.

Mining and processing of transition/fresh ore began in Q4 2017. Mining activities transitioned from mainly oxides in early 2018 to mainly fresh ore by the end of 2019. Ore was mined from the Vindaloo Main Pit Stages 1, 2 and 3 and Vindaloo Central and Bouéré pits to feed the process plant in 2019. Additional oxide will be mined in 2020 and 2021 as Kari Pump comes into production.

Ore mined is hauled to the RoM pad and near RoM stockpiles. Waste mined from the pit is hauled to the waste dumps and other projects requiring waste material for construction (i.e. tailing storage facility, haul roads etc.). Blasted material is excavated in 3m high flitches. African Explosives Limited (“AEL”) provides in-the-hole blasting services. The AEL plant on site consists of an ammonium nitrate mixing shed for the manufacturing of bulk explosives and four 30 tonne capacity iso-tank containers for storage. The supply of detonators, boosters, bulk explosives, initiating systems and other explosives material into the site-based magazines for storage is the responsibility of AEL.

The production drilling and blasting operations are carried out at 9m benches that is then double battered to 18m double benches in fresh rock. Each 9m bench is then excavated in 3m flitches to ensure maximum selectivity and equipment productivity. The average blasting powder factor is between 0.90kg/bcm to 0.98kg/bcm (ammonium nitrate/fuel oil “ANFO” equivalent) for the transitional and fresh rock with a density above 2.0t/m3 and emulsion is used in both wet and dry blasting. The highly weathered zone (clays and laterites) and transitional zone with a density below 2.0t/m3 is classed as free dig as per the current mining practice.

Crushing
The run of mine ore is delivered to a jaw crusher which reduces the ore to less than 200mm. The crushed ore is then transferred to a surge bin with a 30-minute capacity, or, when needed, to an emergency stockpile. During normal operation, the crushed ore from the surge bin is transported to the grinding circuit via a conveyor. In case of a breakdown or maintenance of the crushing circuit, crushed ore is recovered from the emergency stockpile by a loader and directed to the surge bin.

Grinding
The primary grinding circuit consists of a standard Semi-Autogenous Grinding (“SAG”)/Ball and Scats Crushing circuit which was originally designed treat 3.0Mtpa (now operating at 4.0Mtpa) to produce a product where 80% is sub 90µm in size. A portion of freshly ground ore is directed to the gravity circuit where coarse liberated gold in recovered and leached via an intensive leach reactor, followed by electrowinning and eventual gold recovery.

The “Houndé Process Plant” consists of a Carbon-in-Leach (“CIL”) plant with a nameplate capacity of 3.0Mt per annum (now operating at 4.0Mtpa) with Semi-Autogenous Ball Mill Crusher (“SABC”) milling circuit to produce an 80% passing 90-micron grind size. Ground fresh ore is fed to continuous centrifugal gravity concentrators to recover free and occluded gold in heavy particles (pyrite) to a low mass gravity concentrate. This gravity concentrate is processed through an intensive cyanide leach reactor followed by electrowinning to recover the gold. The CIL feed has the potential to be thickened and fed into a standard CIL circuit, with leach tails passing into a cyanide destruction process before being pumped to the Tailings Storage Facility (“TSF”).

Leaching
Ore that is not recovered via the gravity circuit is screened to remove any extraneous trash (wood, plastic, etc.) then can either be sent to a thickener to increase thepercentage solids in the leach slurry, or pumped directly to a conventional carbon in leach circuit (“CIL”). The CIL circuit consists of a series of six agitated tanks where gold is dissolved in the presence of cyanide and oxygen as the slurry flows sequentially from Tank 1 to 6. The dissolved gold adsorbs on the coarse activated carbon particles which are pumped in a counter-current direction from Tank 6 to 1, becoming progressively more loaded with gold in the process;

Carbon Recovery
Once sufficiently loaded by the time the carbon reaches Tank 1, the carbon granules are pumped from the primary tank over a screen to remove the slurry. The clean carbon is then washed with hydrochloric acid to remove any acid soluble base metals and impurities, before being transferred to the elution circuit;

Elution and Gold Production
Concentrated cyanide solution is circulated in the elution column and heated to 120 degrees Celsius. After sufficient time to enable the gold to be released from the carbon, the gold bearing solution is sent for electrowinning and eventual gold bullion production; and

Tailing Detoxification and Disposal
The leached slurry, with minimal leachable gold remaining exits the CIL where the free and weak acid dissociable cyanide (“WAD”) are destroyed through a cyanide detoxification process using sulphur dioxide and oxygen with a copper catalyst to destroy the remaining cyanide complexes. The detoxified tailings are pumped to a plastic lined TSF, where the solid and liquid phases separate. The liquid phase is recycled back to the process plant and the solids allowed to dry and compact in the TSF.