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