Kibali Gold Mine Recovery: Dual Oxide & Sulphide Circuits

NI 43-101 Technical Report on the Kibali Gold Mine

Executive Summary

The Kibali Gold Mine processing facility operates two largely independent circuits designed to accommodate distinct ore types: an Oxide and Free-Milling Circuit and a Sulphide Refractory Circuit. The Oxide circuit utilizes standard crushing, ball milling, gravity recovery via Knelson concentrators, and a conventional CIL circuit. The Sulphide Refractory Circuit employs primary and secondary crushing, milling, flash and conventional flotation, ultrafine grinding (UFG), and cyanidation via a Pumpcell CIP circuit. Both circuits offer operational flexibility to process sulphide ore as oxide sources deplete.

Ore blending is a critical operational function to homogenise feed characteristics across both circuits, ensuring consistent plant feed and maximising gold recovery. Ore is sourced from the KCD underground mine (predominantly sulphide) and satellite open pits (primarily oxide and transition). The plant throughput is designed for 3.6 Mtpa per circuit (7.2 Mtpa total), with 2025 actual throughput exceeding design at 8.32 Mt. The facility includes a Cyanide Removal Plant (AZ-CRP) to treat CIL tails and comply with ICMI standards.

Processing Overview

Website: https://www.barrick.com/English/operations/kibali/default.aspx

Report Date: 2026

Region: Kibali

Project Status:

Commodity: Gold

Throughput: 

Mine Life: 

Mine Type: 

Ore type:

Kibali Gold Mine — 2025 Technical Report

Executive Summary

The Kibali Gold Mine processing facility operates two largely independent circuits designed to accommodate distinct ore types based on mineralogical and metallurgical characteristics: an Oxide and Free-Milling Circuit and a Sulphide Refractory Circuit. The plant has demonstrated steady improvement in utilization and availability since 2013, with 2025 throughput exceeding design capacity at 8.32 Mt treated. The dual-stream configuration supports operational flexibility, enabling either circuit to process sulphide ore as required and allowing for a progressive transition to full sulphide ore processing as oxide sources are depleted.

Ore blending is a critical operational function designed to homogenize ore feed characteristics and optimize metallurgical recovery and throughput across both circuits. Ore is sourced from the KCD underground mine and a series of satellite open pits, with blending operations coordinated through segregated stockpiling, daily blend scheduling, and rigorous quality control. The processing plant includes primary and secondary crushing, milling, gravity concentration, flotation, and cyanidation via CIL and CIP circuits, supported by a dedicated Cyanide Removal Plant (AZ-CRP) to comply with ICMI standards.

The facility is designed for a total throughput of 7.2 Mtpa when processing sulphide ore exclusively, with current operations managing a mix of oxide, transition, and sulphide ores. Power demand averages approximately 41 MW, supported by a hydropower system with thermal generation redundancy. Reagent consumption data for 2025 indicates stable usage of cyanide, lime, and grinding media, with specific energy consumption reduced to 26.9 kWh/t in 2025 compared to 28.5 kWh/t in 2015.

Website: https://www.anglogoldashanti.com/portfolio/africa/kibali/

Report Date: 2025

Region: DRC

Project Status:

Commodity: Gold

Throughput: 

Mine Life: 

Mine Type: 

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Kibali Gold Mine — 2024 Technical Report

Executive Summary

The Kibali Gold Mine processing plant is an operating facility located in the Democratic Republic of Congo, treating ore from both underground (KCD) and satellite open pit sources. The plant is designed to handle a combined throughput of 7.2 Mtpa, split between oxide and sulphide circuits, with the capability to process sulphide ore exclusively once oxide sources are depleted. Operational performance has demonstrated consistent recovery rates, averaging 89.8% in 2021, with a total annual production of 812,152 oz Au.

The processing flow sheet is complex, accommodating both free-milling oxide ore and refractory sulphide ore. Oxide ore follows a standard crushing, milling, gravity recovery, and Carbon-in-Leach (CIL) circuit. Sulphide ore requires additional steps including flotation, ultra-fine grinding, pre-oxidation, and a dedicated Pumpcell Carbon-in-Pulp circuit to recover gold locked in sulphide minerals. The plant utilizes industry-standard technology including Polysius ball mills, Outotec flotation cells, and Kemix Pumpcells.

Operational metrics indicate high plant availability and utilisation, reaching 95.4% availability and 99.1% utilisation in 2021. Specific energy consumption has decreased to 25.8 KWh/t, and water consumption is stabilised at 1.30 m3/t. Processing costs for 2021 were recorded at $16.47/t combined process and plant engineering, with forecasts suggesting continued efficiency improvements through the Life of Mine.

Entities

Website: https://www.anglogoldashanti.com/portfolio/africa/kibali/

Report Date: 2024-11-25

Region: DRC

Project Status:

Commodity: Gold

Throughput: 

Mine Life: 

Mine Type: 

Ore type:

Kibali Gold Mine — 2022 Technical Report

Executive Summary

The Kibali Gold Mine processing plant, operational since 2013, treats a blend of KCD underground ore and ore from satellite open pits. The facility features two largely independent processing circuits designed for oxide, transition, and free-milling ore sources, as well as sulphide refractory ore. Both circuits are designed to be switched to process sulphide ore exclusively when oxide sources are depleted. The plant has demonstrated consistent recovery performance and operational stability, with 2021 throughput reaching 7,783 kt and an average gold recovery of 89.8%.

The processing flow sheet includes crushing, ball milling, classification, gravity recovery, conventional CIL circuit, flash flotation, and conventional flotation. For sulphide ore, the circuit includes ultra-fine grinding, a Pumpcell circuit, and a dedicated intensive cyanide leach circuit. The plant rated throughput is 3.6 Mtpa for oxide and 3.6 Mtpa for sulphide, totaling 7.2 Mtpa when operating on sulphide only. Recent modifications to the crushing circuit have allowed for higher throughputs beyond design capacity.

Operational costs for 2021 were $16.47/t, with specific energy consumption reduced to 25.8 KWh/t. The plant utilizes industry standard technology appropriate for the mineralisation style, including Sandvik crushers, Polysius ball mills, and Outotec flotation cells. Power demand ranges between 39 MW and 43 MW, supported by a hydropower system and thermal generation redundancy. The facility is considered to have matured to steady-state operations with no fatal flaws determined.

Reports

Processing Profile

• Crushing: Primary Jaw Crusher (Sandvik CJ815), Secondary Cone Crusher (Sandvik CS660)
• Milling: Polysius Ball Mills (2 units)
• Flotation: Outotec forced air rougher flotation cells (70 m3)
• Gravity: Knelson gravity concentrators
• Leaching: Carbon-in-Leach (CIL), Carbon-in-Pulp (Pumpcell), Inline Leach Reactor (ILR)
• Ultra-Fine Grinding: VXP2500 FL Smidth ceramic bead mills

Website: https://www.barrick.com/English/operations/kibali/default.aspx

Report Date: 2022

Region: Democratic Republic of Congo

Project Status: Operating

Commodity: Gold

Throughput: 7.2 Mtpa (Design)

Mine Life: 

Mine Type: Underground and Open Pit

Ore type:

Kibali Gold Mine — 2018 Technical Report (Recovery Methods)

Executive Summary

The Kibali processing plant treats blended ore from KCD underground sources and satellite open pits. The plant comprises two largely independent processing circuits: one designed for oxide, transition, and free-milling ore, and a second for sulphide refractory ore. Both circuits are designed to process sulphide ore when oxide sources are depleted. The plant has demonstrated consistent recovery performance since 2015. Design capacity is 3.6 Mtpa per circuit, totaling 7.2 Mtpa for sulphide-only operation. Actual throughput in 2017 exceeded design capacity. Overall gold recovery in 2017 averaged 83.4%.

Processing Methods

• Crushing: Primary Jaw (Sandvik CJ815), Secondary Cone (Sandvik CS660)
• Milling: Ball mills (Polysius) in closed circuit with cyclones
• Gravity: Knelson concentrators and Gekko ILR
• Flotation: Outotec forced air rougher cells and flash flotation
• Leaching: Carbon-in-Leach (CIL) and Pumpcell (CIP) circuits
• Grinding: Ultra-fine grinding (UFG) using ceramic bead mills

Production History

Plant operating since 2013. 2017 production included 7,618 kt of ore treated with an average grade of 2.84 g/t Au.

Costs

2017 Combined Plant & Engineering cost was $18.71/t. LOM budget is $17.24/t.

Website: 

Report Date: 2018-09-18

Region: Democratic Republic of the Congo

Project Status: Operating

Commodity: Gold

Throughput: 7.2 Mtpa (design)

Mine Life: Operating since 2013

Mine Type: Underground and Open Pit

Ore type:

Kibali Gold Mine: Dual-Circuit Processing for High Gold Recovery

Source: Unnamed_Company_45 (2026)
Website: https://www.anglogoldashanti.com/portfolio/africa/kibali/

Critical Data

Overview

The Kibali Gold Mine, operated by AngloGold Ashanti in the Democratic Republic of the Congo, stands as one of Africa’s premier gold processing facilities. Located in the Moto Greenstone Belt, the mine has been in operation since 2013 and processes a geometallurgically diverse ore feed sourced from the KCD underground mine and satellite open pits. The processing plant employs two largely independent circuits—an Oxide and Free-Milling Circuit and a Sulphide Refractory Circuit—designed to handle ore types ranging from soft oxides to hard, gold-locked sulphides. This dual-stream configuration, with a combined design capacity of 7.2 Mtpa, has consistently exceeded throughput targets, treating 8.32 Mt in 2025. The significance of Kibali’s recovery methods lies in their operational flexibility: both circuits can process sulphide ore as needed, enabling a progressive transition to full sulphide processing as oxide sources deplete. Ore blending is central to the plant’s success, with daily scheduling based on grade, hardness, and sulphide content to homogenize feed and optimize metallurgical performance. Key processes include primary and secondary crushing, ball milling, gravity recovery using Knelson concentrators, flash and conventional flotation, ultrafine grinding (UFG) to a P80 of 23 μm, and cyanidation via CIL and Pumpcell CIP circuits. With excellent plant availability exceeding 95% and specific energy consumption reduced to 26.9 kWh/t, Kibali’s recovery methods demonstrate world-class efficiency and adaptability for complex gold ores.

Key Process Stages

• Stage 1: Ore Blending and Stockpile Management – Ore from multiple sources is segregated into dedicated stockpiles based on metallurgical domain (oxide, transition, sulphide). Real-time monitoring of volumes and grades via weighing systems and frequent assays enables daily blend scheduling to achieve target head grade, arsenic thresholds, and Bond Work Index. Blending optimizes grinding energy and flotation/leaching performance.
• Stage 2: Crushing and Grinding – Sulphide ore undergoes primary (Sandvik CJ815 jaw crushers) and secondary (Sandvik CS660 cone crushers) crushing to a P80 of 45 mm, then reports to a 11,700 t Fine Ore Stockpile. Oxide ore may bypass secondary crushing. Both circuits use ball mills in closed circuit with cyclones: oxide circuit target grind P80 80 μm; sulphide circuit target P80 75 μm. A hybrid roll crusher is available for harder transitional ore.
• Stage 3: Gravity Recovery and Flash Flotation – Cyclone underflow from both circuits passes through Knelson gravity concentrators to recover free native gold as a coarse concentrate. Flash flotation cells operate optionally when processing free-milling fresh ore. The gravity concentrate is leached in a Gekko Inline Leach Reactor (ILR), with pregnant solution sent directly to electrowinning.
• Stage 4: Flotation and Ultrafine Grinding (Sulphide Circuit) – Cyclone overflow reports to two parallel banks of six 70 m³ Outotec forced air flotation cells for rougher flotation. Rougher concentrate (combined with flash flotation concentrate) is thickened and then fed to eight FLSmidth VXP2500 ceramic bead mills in parallel, achieving an ultrafine grind P80 of 23 μm. This liberation step is critical for recovering gold locked in sulphide minerals.
• Stage 5: Leaching and Carbon Adsorption – The oxide circuit uses a conventional CIL circuit with nine tanks (two pre-oxidation with Aachen reactors, seven adsorption tanks). The sulphide circuit employs a pre-oxidation stage with Aachen reactors, extended leach in 2,100 m³ tanks, and eight 100 m³ Kemix Pumpcell tanks in carousel mode for CIP. Loaded carbon from both circuits is eluted via AARL 12-tonne batch circuits, with electrowinning and smelting producing doré. CIL tails are treated in a 4.8 Mtpa AZ-CRP® cyanide removal plant to meet ICMI standards.

Additional Interesting Data and Summary

The Kibali processing plant’s technical excellence is underpinned by robust power and water management. The site’s hydropower system delivers a peak of 42.8 MW, supplemented by 43 MW of thermal generation, providing full redundancy. Total mine load averages 41 MW, ensuring reliable operation. Water demand has stabilized at 11.5 Mm³ per annum, with a specific consumption of 1.38 m³/t, reflecting efficient recirculation and tailings management. Reagent consumption in 2025 highlights the plant’s optimized chemistry: cyanide averaged 0.638–0.672 kg/t, lime 1.138–1.314 kg/t, and grinding media 0.527–0.546 kg/t across quarters. The recently installed AZ-CRP® cyanide removal plant, with a capacity of 4.8 Mtpa, treats CIL tailings to comply with International Cyanide Management Institute (ICMI) standards while recovering additional gold and copper. Environmental sustainability is furthered by the use of hydropower, which reduces the carbon footprint compared to diesel generation. The plant’s workforce includes 570 direct employees and 245 contractors, with specialist partners for TSF management, plant cleaning, and oxygen production. Looking forward, as oxide and free-milling ore sources deplete, the existing oxide circuit will be converted to a parallel sulphide circuit, necessitating expansion of concentrate handling and Pumpcell capacity. The current feed plan already operates with 30% oxide–sulphide campaign per year, with the rest treating only sulphide ores. The original UFG section was expanded in 2017 to eight VXP2500 mills, and further upgrades are anticipated. The Qualified Person has confirmed that the current facilities are suitable for processing the ores outlined in the Life-of-Mine plan, underscoring Kibali’s long-term viability as a world-class gold producer.

Key Processes: Flotation, CIP/CIL, Cyanidation, Gravity Separation, Ball Mill, Crushing

Target Commodities: Gold, Copper, Lead

Kibali Gold Mine Recovery: Dual Circuit Gold Processing

Source: Barrick North America Finance LLC (2026)
Website: https://www.barrick.com/

Critical Data

Overview

The Kibali Gold Mine, located in the northeastern Democratic Republic of Congo within the Neoarchean Moto Greenstone Belt, operates one of the most sophisticated gold processing facilities in Africa. Managed by Barrick Gold Corporation, the plant has been in operation since 2013 and has achieved exceptional performance, treating over 8.32 million tonnes in 2025. The facility is strategically designed with two largely independent circuits to handle distinct ore types—oxide and free-milling ore in one circuit, and sulphide refractory ore in the other. This dual-stream configuration allows for operational flexibility, enabling progressive transition as oxide resources deplete. The processing strategy integrates advanced gold recovery methods including primary and secondary crushing, ball milling, gravity concentration via Knelson concentrators, flash and conventional flotation, ultrafine grinding (UFG), and carbon-in-leach (CIL) or Pumpcell carbon-in-pulp (CIP) circuits for maximum gold extraction. Ore blending is critical to homogenize feed and optimize metallurgical performance, with stockpile management and daily blend scheduling based on grade, hardness, and sulphide content. The plant’s significance lies in its ability to recover gold from complex refractory ores while maintaining high availability and utilization rates exceeding 95% and 99% respectively. This comprehensive approach ensures Kibali remains a world-class gold producer.

Key Process Stages

• Stage 1: Crushing and Grinding — Run-of-mine ore undergoes primary crushing using Sandvik CJ815 jaw crushers (two units) followed by secondary crushing with Sandvik CS660 cone crushers to achieve a P80 of 45 mm. For the oxide circuit, an optional hybrid roll crusher handles harder transitional ores. The crushed ore is fed to ball mills operating in closed circuit with cyclones. The oxide circuit targets a grind size of P80 80 µm, while the sulphide circuit targets P80 75 µm.
• Stage 2: Gravity Concentration and Flash Flotation — Cyclone underflow from both circuits is directed to Knelson gravity concentrators to recover coarse free gold, which is then leached in a Gekko Inline Leach Reactor (ILR). Flash flotation cells are used optionally when processing free-milling ore to capture additional coarse sulphide-associated gold, enhancing overall recovery before conventional flotation.
• Stage 3: Flotation and Ultrafine Grinding — For sulphide refractory ore, cyclone overflow feeds rougher flotation using two parallel banks of six Outotec forced air flotation cells (70 m³ each). Rougher concentrate, combined with flash flotation concentrate, is thickened and then ground in eight VXP2500 FLSmidth ceramic bead mills to a P80 of 23 µm, liberating gold locked within sulphide minerals.
• Stage 4: Pre-oxidation and Leaching — The ultrafine ground concentrate undergoes pre-oxidation in two tanks equipped with Aachen reactors, where lime, oxygen, and lead nitrate are added. Pre-leach is performed with cyanide and lime addition, followed by extended leaching in two 2,100 m³ tanks with Aachen-assisted aeration to maximize gold dissolution from the refractory concentrate.
• Stage 5: Carbon Adsorption, Elution, and Gold Recovery — Leached slurry from the sulphide circuit reports to eight 100 m³ Kemix Pumpcell tanks operating in carousel mode for counter-current carbon adsorption. The oxide circuit uses a conventional CIL circuit with nine tanks. Loaded carbon from both circuits is processed in parallel 12-tonne AARL elution circuits, with electrowinning and smelting producing doré bars. CIL tails undergo detoxification in a new Cyanide Removal Plant (CRP) using AZ-CRP technology.

Additional Interesting Data and Summary

The Kibali processing plant demonstrates world-class operational performance with plant availability consistently above 95% and utilization exceeding 99% since 2017. The facility treats ore from the KCD underground mine (predominantly sulphide) and satellite open pits (oxide and transition). Power supply is secured by a hybrid system comprising 42.8 MW hydropower and 43 MW thermal generation with full redundancy. The plant’s specific energy consumption has steadily declined from 28.5 kWh/t in 2015 to 26.9 kWh/t in 2025, attributed to underground ore pre-crushing to P80 <50 mm. Water demand has stabilized at approximately 11.5 million cubic metres per annum with specific consumption of 1.38 m³/t. Reagent consumption in 2025 shows efficient usage: cyanide averaged 0.638–0.672 kg/t, lime 1.138–1.314 kg/t, and grinding media 0.527–0.546 kg/t. The recently installed AZ-Cyanide Removal Plant (CRP) with 4.8 Mtpa capacity ensures compliance with ICMI standards by reducing cyanide levels in tailings while recovering additional gold. The CRP uses six patented upflow reactors for adsorption, copper elution, acidification, and HCN scrubbing. Environmentally, the use of hydropower significantly reduces the carbon footprint of gold production. The processing plant employs 570 staff and 245 contractors, with specialized contractors for TSF management (Paragon), plant cleaning (Lutula & Munguleni), and oxygen supply (Air Liquide). The current feed plan allows for 30% of the year operating in oxide–sulphide campaign mode, with the remainder treating only sulphide ores. As oxide and transition sources deplete, the oxide circuit can be converted to a parallel sulphide circuit, expanding concentrate handling and Pumpcell capacity. The Qualified Person opines that the existing facilities are suitable for processing the ores envisaged in the Life-of-Mine plan, ensuring Kibali’s sustained contribution as one of the largest gold mines in Africa.

Key Processes: Flotation, CIP/CIL, Cyanidation, Gravity Separation, Ball Mill, Crushing

Target Commodities: Gold, Copper, Lead