Séguéla Gold Mine — 2025 Technical Report

This technical report details the processing facilities, design criteria, and operational performance for the Séguéla gold mine in Côte d’Ivoire.

Report context

This technical report is dated December 31, 2025, and addresses the Séguéla Gold Mine project in Côte d’Ivoire. The report describes the process plant design, which is based on a metallurgical flowsheet envisioned to produce gold doré while minimizing initial capital expenditure and operating costs. The flowsheet consists of crushing, milling, gravity recovery, a CIL circuit, carbon elution, and a gold recovery circuit, with CIL tails disposed in a high-density polyethylene (HDPE)-lined tailings storage facility.

Processing route

Crushing and Materials Handling

The crushing circuit is designed for 75% availability. Run-of-mine material is trucked from the pit to the ROM pad and reclaimed by a front-end loader into the ROM bin. Ore is drawn via an apron feeder and scalped over a vibrating grizzly, with undersize reporting directly to the discharge conveyor and oversize reporting to a primary jaw crusher. All crushed and scalped material is conveyed to a surge bin providing approximately 30 minutes of surge capacity. The excess capacity allows for routine crusher maintenance without interrupting mill feed.

Grinding and Classification

The grinding circuit uses a single stage semi-autogenous grinding (SS SAG) mill in closed circuit with a classifying cyclone pack. SAG mill trommel oversize is directed to a scats bunker and returned to mill feed via a front-end loader, while undersize gravitates to the cyclone feed pump box. Cyclone overflow gravitates to a trash screen before reporting to the pre-leach thickener, and cyclone underflow returns to the SAG mill feed chute. A portion of the cyclone underflow is directed to the gravity concentration circuit.

Provision was made for expansion to convert the SS SAG circuit into a SAG and ball milling circuit (SABC). Alternatively, throughput could be increased to 1.57 Mtpa by maintaining the SS SAG circuit but coarsening the grind to 106 µm.

Gravity Recovery and Intensive Cyanidation

The gravity circuit comprises a centrifugal concentrator with a feed scalping screen. Feed is extracted from the cyclone underflow discharge launder and flows by gravity to the scalping screen. Oversized material at +2 mm reports to mill feed. The gravity concentrator operates on a semi-batch basis, with concentrate collected in a storage cone and subsequently leached in an intensive cyanidation reactor circuit (ICR). ICR leach solution (2% w/v NaCN and 2% w/v NaOH) is made up in a heated vessel feed tank, with oxygen sparged into the reactor. Gold is recovered from the ICR pregnant solution using a dedicated electrowinning cell.

Pre-Leach Thickening and Leaching

Cyclone overflow passes over a trash screen to remove foreign material, then gravitates to the pre-leach thickener where solids concentration is increased prior to leaching. The leach circuit consists of one pre-leach tank and six CIL tanks. Oxygen can be sparged to each tank. Cyanide solution is added to the pre-leach tank and the first three CIL tanks. Fresh or regenerated carbon is returned to the last CIL tank and advanced counter-currently by airlifts. Slurry from the last CIL tank passes over a vibrating carbon safety screen before reporting to the tailings hopper and being pumped to the HDPE-lined TSF.

Carbon Elution, Regeneration, and Gold Recovery

Loaded carbon is treated with a 3% w/v hydrochloric acid solution to remove deposits prior to stripping. Carbon stripping uses the split Anglo American Research Laboratories (AARL) process. The elution sequence commences with pre-soaking at 95°C using a 2% w/v NaOH and 2% w/v NaCN solution, followed by elution under pressure at 125°C. Carbon is reactivated in a diesel-fired rotary kiln at 700–750°C in an atmosphere of superheated steam.

Gold is recovered from pregnant eluate by electrowinning using stainless steel mesh cathodes. Gold sludge is washed off, dried, mixed with fluxes, and smelted in a diesel-fired furnace to produce gold doré.

Reagent Handling and Control Systems

Reagent preparation and storage facilities are located within containment areas designed for 110% of the largest storage tank volume. Reagent systems installed include quicklime, sodium cyanide, sodium hydroxide, hydrochloric acid, flocculant, activated carbon, anti-scalant, and smelting fluxes.

The plant control system comprises programmable logic controllers beneath a supervisory control and data acquisition network layer. Communication is via a plant-wide Ethernet network using single-mode fiber optic cables.

Key reported parameters

Note: Actual gold recovery of 93.5% is from operational data collected prior to the data cut-off date at an average mill feed rate of 216 t/h and head grade of 2.87 g/t Au.

Technical qualifications

The qualified person considers process requirements to be well understood, with commissioning and ramp-up operating data confirming design assumptions. The report notes there is no indication that the characteristics of the material being mined will change, and therefore the processing and recovery assumptions applied for future mining, including from other deposits, are considered reasonable for the life-of-mine plan. The plant is described as being of conventional design using readily available consumables.

*Source: Séguéla Gold Mine, Côte d’Ivoire , Technical Report, December 31, 2025, Sections 17.1–17.9.*