Burkina Faso

Hounde Mine

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Overview

Mine TypeOpen Pit
Commodities
  • Gold
Mining Method
  • Truck & Shovel / Loader
Production Start2017
Mine Life2031
ShapshotThe Houndé mine is one of Endeavour’s cornerstone assets, where the goal is to sustain production above 250koz/year.

Owners

SourceSource
CompanyInterestOwnership
Government of Burkina Faso 10 % Indirect
Endeavour Mining plc 90 % Indirect
The Houndé exploitation permit is held by Houndé Gold Operation SA ('HGO'). The Bouéré exploitation permit is held by Bouéré-Dohoun Gold Operation SA ('BDGO'). HGO and BDGO are each held 90% by the Endeavour Mining and 10% by the Government of Burkina Faso ('GoBF').

The Endeavour Mining indirectly owns 1324.17 km² of the Houndé mineral titles.

Contractors

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Deposit type

  • Vein / narrow vein
  • Sediment-hosted
  • Breccia pipe / Stockwork
  • Volcanic hosted

Summary:

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 property contains five north-northeast-south-southwest striking geological domains. From east to west these include: basement gneisses, migmatites, and granitoids; a belt of phyllitic metasedimentary rocks including mudstones, siltstones, phyllites, and sericitic schists; the Eastern Volcanic Domain; a Tarkwa-type sedimentary basin; and the Western Volcanic Domain.

Reserves

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Mining Methods

  • Truck & Shovel / Loader

Summary:

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 Maxam Corp carry out drilling and blasting activities. Mining and processing began in Q4 2017.

The in-pit material excavation is conducted by a fleet of nine Komatsu excavators consisting of one PC3000-8R, three PC 2000-8R, one PC2000-11R and four PC 1250-8R. Material haulage is done by 41 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 to determine final ore/waste boundaries and in-pit mark-up. Production drilling and blasting is performed on contract by SFTP with Sandvik DP1500s drill rigs on (9 to 10) m benches with 1 m sub-drill using (115 to 140) mm diameter drill bits. Blasted material is commonly excavated in (3 to 5) m high flitches.

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 sterilised before dumping commences.

In 2023, a total of 47.7 Mt material was mined and 5.4 Mt of ore was moved from the pits at an average grade of 1.94 g/t containing 339 koz of gold.

Comminution

Crushers and Mills

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Processing

  • Gravity separation
  • Carbon re-activation kiln
  • INCO sulfur dioxide/air process
  • Intensive Cyanidation Reactor (ICR)
  • Smelting
  • Centrifugal concentrator
  • Electric furnace
  • Crush & Screen plant
  • Agitated tank (VAT) leaching
  • Counter current decantation (CCD)
  • Carbon in leach (CIL)
  • Carbon adsorption-desorption-recovery (ADR)
  • AARL elution
  • Solvent Extraction & Electrowinning
  • Cyanide (reagent)

Summary:

Construction of the processing 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 plant with a nameplate capacity of 3.0 Mt/a. The flowsheet includes a single stage jaw crusher, a 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, the Company launched an incremental optimisation programme at 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 5.5 Mt in 2023.

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;

Once the elution cycle is complete, recovery of gold and silver by electrowinning proceeds. Direct current is passed through stainless steel anodes and stainless-steel mesh cathodes within the electrowinning cells. Electrolytic action causes the gold and silver in solution to plate out on the cathodes and three electrowinning cells arranged in parallel are in operation with electrowinning taking approximately 8 to 12 hours. An overhead crane (2t capacity) is provided to assist with handling of cathodes and anodes. The cathodes are washed with high pressure spray water and the gold sludge is recovered in a vacuum pan filter. The gold sludge filter cake is dried in an oven and direct smelted with fluxes in an electric induction furnace to produce doré bars.

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 INCO 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.

Recoveries & Grades:

CommodityParameter2023202220212020201920182017
Gold Recovery Rate, % 91939293939495
Gold Head Grade, g/t 1.921.922.132.211.832.292.75

Production

CommodityUnits2024202320222021202020192018Avg. Annual (Projected)LOM (Projected)
Gold koz 0000000000000000000002771901,906
All production numbers are expressed as metal in doré. ^ Guidance / Forecast.

Operational metrics

Metrics202320222021202020192018
Stripping / waste ratio 7.8 6.91 10.4 7.17 11.9 6.13
Ore tonnes mined 5,420 kt5,754 kt4,397 kt5,324 kt2,969 kt5,822 kt
Waste 42,260 kt39,736 kt45,520 kt38,171 kt35,225 kt35,667 kt
Total tonnes mined 47,680 kt45,490 kt49,917 kt43,495 kt38,194 kt41,489 kt
Tonnes processed 5,549 kt5,043 kt4,622 kt4,228 kt4,144 kt3,948 kt
Annual processing capacity 4.5 Mt3 Mt3 Mt3 Mt3 Mt
Daily processing capacity 9,000 t

Production Costs

CommodityUnitsEstimated202320222021202020192018
Total cash costs (sold) Gold USD 0000000 0000000 0000000 0000000 662 / oz   459 / oz  
All-in sustaining costs (sold) Gold USD 00000000 0000000 0000000 0000000 0000000 875 / oz   564 / oz  
^ Guidance / Forecast.
Net of By-Product.

Operating Costs

Currency2023202220212020201920182017
OP mining costs ($/t mined) USD 3.42  2.76  2.11  2.47  2.23  1.91  1.33  
Processing costs ($/t milled) USD 11.5  11.5  13.3  14.1  12.5  11.7  6.81  
G&A ($/t milled) USD 5.35  5.35  5.24  4.91  6.11  6.11  

Financials

Units2024202320222021202020192018
Capital expenditures (planned) M USD 60  
Sustaining costs M USD 33.9  32  49.1  37.1   23.1   7.2  
Capital expenditures M USD 75.3  73.9  78.2  59.2   40.3  
Revenue M USD 613.6  533.5  522.3  494   316.1   351.1  
Operating Income M USD 262.4  235.5  242.6  236.1   69.9   135.8  
Pre-tax Income M USD 62.5   121.6  
After-tax Income M USD 46.3   81.4  
EBITDA M USD 324.7  298.7   143.3  

Heavy Mobile Equipment

HME TypeModelSizeQuantityLeased or
Contractor
Ref. DateSource
Dozer 9 Dec 31, 2023
Drill Sandvik DP1500 Leased Dec 31, 2023
Excavator Komatsu PC3000-8R 1 Dec 31, 2023
Excavator Komatsu PC2000-8R 3 Dec 31, 2023
Excavator Komatsu PC1250-8R 4 Dec 31, 2023
Excavator Komatsu PC450 2 Sep 30, 2022
Excavator Komatsu PC2000-11R 1 Dec 31, 2023
Grader Komatsu GD825A-2 4 Dec 31, 2023
Loader (FEL) Komatsu WA500-6R 30 t 2 Sep 30, 2022
Loader (FEL) Komatsu WA600-6R 50 t 3 Sep 30, 2022
Loader (FEL) Komatsu WA800-3 100 t 2 Sep 30, 2022
Truck (dump) Komatsu HD785-7 41 Dec 31, 2023
Truck (service) Komatsu HD465-7R 2 Dec 31, 2019
Truck (water) Komatsu HD465-7R 50 m3 4 Dec 31, 2023

Personnel

Mine Management

Source Source
Job TitleNameProfileRef. Date
Fixed Plant Maintenance Superintendent Ackim Lungu LinkedIn May 8, 2024
Mobile Maintenance Superintendent Jeremie Hien LinkedIn May 8, 2024
Procurement Superintendent Nina Pare LinkedIn May 8, 2024
Regional Senior Buyer Gisèle Bountoulgou LinkedIn May 8, 2024

EmployeesContractorsTotal WorkforceYear
1,271 1,139 2,410 2023
1,276 1,755 3,031 2022
1,860 2021
1,287 2020
1,119 2019
1,038 2018
2,000 2016

Aerial view:

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