On the Houndé land package, six deposits have been discovered with Vindaloo being the main and historical one leading to the construction of the mine. The six deposits are Vindaloo, Bouéré, Dohoun, Kari Pump, Kari West and Kari Center. Bouéré, Dohoun, and Kari Centre are small satellite deposits while Vindaloo, Kari Pump and Kari West host most of the current resources and are summarized in this section. In 2021, extensions of the Kari Centre deposit included the Kari Gap and Kari South deposits, a continuation of the same mineralizing system. Mambo is a new discovery, located on an exploration permit approximately 14 km north-northeast of the mine.

The Vindaloo deposits are hosted by Proterozoic-age, Birimian Group, intensely sericite and silica-altered mafic intrusions, similarly-altered, strongly foliated and altered intermediate to mafic volcaniclastics and occasionally sediments. The mineralization is often quartz stockwork style and is weakly to moderately pyritic. The Vindaloo trend has been drill tested for a distance of approximately 7.7 km along strike and up to 350 m in depth. The intrusion-hosted zones range up to 70 m in true thickness and average close to 20 m true thickness along a 1.2 km section of the zone called Vindaloo Main. Volcanic and sediment-hosted zones are generally less than 5 m wide. The entire mineralised package strikes north-northeast and dips steeply to the west to vertical. The mineralization remains open both along strike and to depth.

Geologically, Kari Pump is underlain by andesite flows with minor volcano-sediment and sediments that are locally intruded by few diorite sills. Gold mineralization occurs within a sheared reverse fault (D2) that appears to be folded and dipping from 0° to 40° to the west-northwest and northwest. Observed clear alteration consists of pervasive creamy sericite, intermittent rhodochrosite, chlorite seams and pyritized quartz/carbonate veining. The laterite and saprolite are relatively thick at Kari Pump with an average thickness ranging from 50 m to 85 m.

At Kari West the weathered bedrock and saprolite thickness vary between 25 m and 75 m with thicker zones noted to the south. Laterite up to 20 m thick covers most of the area. The Kari West deposit is located in the hanging wall of a N240 trending and steep northwest-dipping lithological contact zone between dominantly meta-volcanic units (hanging wall) and a dominant metasedimentary unit (footwall). The deposit was formed under purely brittle conditions. The mineralization of Kari West remains open down dip along the low angle structures and steeper and deeply rooted structures and open along the central extend of the deposit on the east (100 m wide) and on the west/southwest.

Kari Center area can be subdivided into three deposits which are Kari Center Main, Kari Gap, and Kari South. The three deposits are continuous, extend up to 3.2 km in length, and cover the same structurally controlled mineralizing system. The stratigraphy of those zones is composed of volcanic rocks interbedded with volcanosediments and locally by graphitic sediments. The laterite thickness ranges between 12 to 20 m and the saprolite reaches 100 metres depth in places. Most of the gold at the Kari Centre Main, Gap and South is concentrated in multiple lenses of variable length and thickness within a northeast striking shear zone. The mineralization is associated with white quartz veins, sericite-albite alteration and disseminated pyrite. The mineralised lenses dip 50° towards the north-west. At Kari South the altered rocks commonly associated with gold mineralization host two mineralised structures. The first structure is oriented north northwest and dips steeply towards the east-northeast while a second structure trends 010° and dips 30° towards the east.

Bouéré is hosted in a mafic to intermediate volcanic sequence, comprised of fine-grained tuffs and pyroclastic andesitic flows and breccia interlayered with more massive basaltic and andesitic flows. Bouéré is structurally complex with two main phases of deformation and associated hydrothermal alteration. It is characterised by lenticular-shaped and fold-shaped mineralised zones trending east - west to northeast – southwest, steeply dipping to the north.

Dohoun is underlain by a package of variably deformed fine-grained volcanic rocks including lava flows‚ volcanic tuffs‚ volcanic breccia and sediments. The Birimian Greenstones are intruded by a massive granodiorite and the overall lithologies are cut by a quartz-feldspar porphyry dyke trending north-northeast. A shear zone trends north-northeast and affects the western margin of the granodiorite intrusive and hosts gold mineralization. It is one to several metres wide comprised of quartz-carbonate veins associated with strong pervasive sericite and sulphides. Two other mineralised vein orientations are observed at Dohoun; north to south veins (interpreted to be associated with early deformational events) and east-northeast oriented fractures within the competent granodiorite intrusion.

At Mambo, mineralised shear zones are interpreted to be exploiting the contact between a granitoid intrusive and hangingwall mafic volcanics. The mineralised trend has been defined over 1,400 m and remains open to the northeast, and at depth. The mineralised lenses range between 10-40 m thick, with higher grades concentrated at the contacts between the volcanics and the granitoid. The gold is hosted within pyrite, with no arsenopyrite observed in drill cuttings. Graphitic shear material has not been observed, and alteration is pervasive sericite with local silica flooding and quartz veining.

The Golden Hill deposit is located within the highly mineralised Houndé Greenstone Belt. This belt hosts the majority of the high-grade discovered gold ouncesin Burkina Faso, including the recently discovered Siou deposit plus the high-grade Yaramoko deposit. The Golden Hill deposit straddles the same stratigraphy and structures that host these high-grade deposits.

The mining method at Houndé is conventional open pit mining including drilling, blasting, loading and hauling. Load and haul activities are owner operated. Contract service providers, SFTP Mining and African Explosives Limited ("AEL"), carry out drilling and blasting activities. Mining and processing of transition/fresh ore began in Q4 2017. In 2021, more oxide was mined as Kari Pump came into production.

The in-pit material excavation is conducted by a fleet of eight Komatsu excavators consisting of one PC3000- 8R, three PC 2000-8R and four PC 1250-8R. Material haulage is done by 35 Komatsu HD785-7 rear dump trucks. Key items of the ancillary fleet are nine dozers, four 50 m3 water trucks and four motor graders. 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.).

The ore control strategy targeting delineation of ore and waste uses RC holes piercing multiple benches. The geological and assay information, obtained from 32 m deep inclined holes are sampled and assayed every 1 m to generate wireframes from sectional interpretation, for grade control block modelling and ore outline generation. The ore outlines are then used by geologists and surveyors for final ore/waste discrimination and in-pit mark-up. In 2018, Houndé introduced blast movement simulation technology to better predict movement of ore resulting from blasting as a key measure in reducing ore loss and dilution. Production drilling and blasting is performed on contract by SFTP with Sandvik DP1500s drill rigs on 9 m benches with one-metre sub-drill using 115 mm diameter drill bits. Blasted material is excavated in 3 m high flitches except for Kari pump flat ore body where 2.5 m flitches are commonly used and 1.25 m flitches in some areas.

During 2021, AEL provided down-the-hole blasting services. The AEL plant on site consisted 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 was the responsibility of AEL. A tender process for blasting services was carried out in 2021 and awarded to Maxam in 2022. Upon winning the tender they have mobilised to site and commenced all blasting activities previously associated with AEL.

Waste rock dumps associated with mining operations are constructed to meet the stipulated guidelines of the Burkina Faso Mining and Explosive and Environmental Regulations. All areas earmarked for waste dumps are sterilized before dumping commences.

During 2022, ore tonnes were mined from a combination of the three main mining areas being Kari Pump, Vindaloo Main and Kari West throughout the year, all of which alternated effectively in terms of the focus between ore mining and waste development. The major waste development stages undertaken in the year were Vindaloo Main pushback in the first half of the year, Kari West development in mid-2022 and at the back end of the year pre-stripping of the Kari Pump stage 3.

In 2023, mining activities will focus on the Vindaloo Main, Kari Pump and Kari West pits. In the first half of 2023, ore is expected to be mined primarily from the Kari West pit, while significant waste stripping is underway at the Kari Pump and Vindaloo Main pits. In the second half of 2023, greater ore volumes are expected be mined from the Kari Pump and Vindaloo Main pits, with Kari West continuing to provide supplemental feed. Production for the year is expected to be weighted towards the second half of 2023 as the waste stripping activities in the first half of 2023 are only expected to provide access to higher grade ore sources at both the Kari Pump and Vindaloo Main pits in the second half of the year. Throughput and recoveries are expected to be slightly lower in 2023 compared to 2022 due to a greater proportion of harder fresh ore in the blend.

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Construction of the CIL plant commenced in April 2016 and was completed with the first gold pour in 2017. Commercial production started in Q4 2017. The processing plant at Houndé consists of a carbon-in-leach ("CIL") plant with a nameplate capacity of 3.0 Mt per annum. The flowsheet includes a single stage jaw crusher, two stage SAG/ball milling comminution circuit, gravity concentration for removal of coarse gold, pre-leach thickener, CIL circuit comprising six tanks, split Anglo (AARL) elution circuit, electrowinning, gold smelting and tailings detoxification.

Following commissioning, Endeavour launched an incremental optimisation of the Houndé processing plant. The crushing circuit capacity was increased via upgraded apron feeder motors and drives, pump modifications and increasing the capacity of the tailings delivery line to the TSF. The Houndé CIL processed 5.0 Mt in 2022.

Gravity
Feed for the gravity circuit is taken from the common mill discharge using a duty/standby pump arrangement. The gravity circuit feed stream is pumped to one of two single deck ‘vibrating ‘degritting’ screen to remove coarse (+2mm) material and fragments of broken mill balls and this oversize is returned to the ball mill feed. The screen undersize stream gravitates to one of two (duty/standby) 48” Knelson centrifugal concentrators and the tails slurry from the centrifugal concentrator gravitates to the mill discharge hopper. The concentrator is operated on a semibatch basis with periodic discharge of the coarse high SG material (gravity concentrate) to the concentrate storage hopper as part of the intensive leach reactor.

The intensive leach reactor (“ILR”) processes the concentrate once per day in a rotating drum leach vessel. Cyanide and caustic together with oxygen are introduced into the slurry and the drum is rotated for up to 20 hours to leach out gold and silver. At the end of this time the pregnant liquor is separated from the solids and pumped to the dedicated pregnant liquor tank. Reactor tails is pumped back to the mill discharge hopper for additional milling to recover any remaining entrained gold and silver.

A dedicated pregnant liquor pump feeds the gravity electrowinning cell in the goldroom with gold and silver recovered onto stainless steel cathodes and barren liquor returned to the pregnant liquor tank. The cathodes from the gravity electrowinning cell are treated separately to assist in metallurgical accounting and spent electrolyte is recycled to the head of the CIL circuit.

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.

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