Endeavour Mining’s ADP Plant: 94% Gold Recovery via HPGR & CIL

Source: Endeavour Mining plc (2026)
Website: https://www.endeavourmining.com/our-portfolio/projects/assafou/

Critical Data

Overview

Endeavour Mining plc operates the Assafo-Dibibango Project (ADP), a gold mine in Côte d’Ivoire, as detailed in the 2025 NI 43-101 Feasibility Study. The processing plant, designed with a nameplate capacity of 5.0 Mt/a (dry basis), will treat predominantly fresh, free-milling ore over a 17-year life of mine (LoM). Metallurgical testwork confirmed that the ore contains a high proportion of gravity-recoverable gold and is amenable to direct cyanidation, similar to Endeavour’s nearby Lafigué project. The weighted-average LoM gold feed grade is 1.76 g/t, with an overall gold recovery of 94%, yielding over 4.1 million ounces of gold. To optimise comminution energy efficiency, the flowsheet replaces a conventional SABC circuit with a two-stage crushing and high-pressure grinding roll (HPGR) circuit. This HPGR-based setup significantly reduces energy consumption and carbon footprint. During the first two years, soft and sticky oxide ore (Laterite/Saprolite) will be managed through a stockpiling and blending strategy, using pre-strip and grade control stockpiles to keep the HPGR feed within acceptable limits. The downstream circuit includes a ball mill in closed circuit with cyclones (target grind 80% passing 106 µm), a gravity gold recovery circuit, and a carbon-in-leach (CIL) plant. The plant incorporates proven technologies, automated controls, and a focus on water recycling and environmental compliance. The ADP process plant is expected to ramp up gold production to an average of 361 koz/a in Years 3–8, with tailings managed via a dedicated storage facility.

Key Process Stages

• Stage 1: Primary Crushing – Run-of-mine ore is delivered to a gyratory crusher dump pocket. The primary crusher reduces ore to a coarse product, which is conveyed to a live stockpile for buffer storage. This stage operates at 70% utilisation (6,132 h/a) to accommodate sporadic truck deliveries.
• Stage 2: Secondary Crushing – Primary crushed ore is reclaimed from the stockpile and fed to secondary cone crushers operating in closed circuit with dry sizing screens. The intermediate product has reduced particle size and is directed to the HPGR feed bin. Utilisation is 86.7% (7,597 h/a).
• Stage 3: Tertiary HPGR Crushing – The HPGR operates in closed circuit with wet milling screens. Oversize material is returned to the HPGR, while undersize slurry reports to the mill discharge hopper and hydrocyclones. A dead HPGR fines stockpile provides emergency feed to the ball mill via front-end loaders. This configuration achieves lower energy consumption than a conventional SABC circuit.
• Stage 4: Ball Milling & Gravity Concentration – The ball mill, in closed circuit with cyclones, grinds the HPGR product to 80% passing 106 µm. A gravity concentration circuit recovers coarse gold from the mill discharge. The gravity concentrate is treated by intensive cyanidation and electrowinning to produce gold doré. Milling and downstream operations are designed for 91.3% utilisation (8,000 h/a).
• Stage 5: CIL Leaching & Gold Recovery – Cyclone overflow passes through a trash screen and then a pre-leach thickener to achieve optimal solids concentration. Leaching occurs in one leach tank followed by six CIL tanks (total 36 h residence time). Loaded carbon is processed via a split AARL elution circuit, electrowinning, and smelting to produce gold doré (>92% w/w gold). CIL tails are thickened, diluted with TSF decant water, and pumped to the tailings storage facility.

Additional Interesting Data and Summary

The ADP process plant is designed to treat 77 Mt of ore over its 17-year LoM, producing 4,115 koz of gold. Gold production ramps up from Year 1 to a peak of 361 koz/a in Years 3–8, then declines as marginal ore (0.5–0.8 g/t) is processed from stockpiles. The HPGR-based comminution circuit was selected specifically to reduce energy consumption and CO₂ emissions compared to a conventional SABC circuit, aligning with Endeavour’s publicly stated energy-efficiency and carbon-reduction targets. Operational planning includes a robust blending strategy using pre-strip and grade control stockpiles to keep the soft/sticky oxide component below 10% of HPGR feed during the first two years. Water supply will come from a Raw Water Harvesting Dam located 13 km southwest, supplemented by boreholes and pit dewatering; plant design emphasises maximum recycle of process water and contact water management to meet IFC and Côte d’Ivoire environmental standards. The plant’s battery limits include ore delivery to the primary crusher, tailings to the TSF, and gold doré shipment off-site. The doré gold grade is expected to exceed 92% w/w with minimal silver content. Utilisation factors (70% for primary crushing, 86.7% for secondary/HPGR, 91.3% for mill and CIL) are based on industry norms and include allowance for scheduled maintenance and emergency stockpile capacity. The feasibility study cost estimate and design assume power continuity via backup generation. Environmental sustainability is further supported by the use of electrical energy for the carbon regeneration kiln and smelting furnace instead of diesel. The project’s long LoM and high recovery rate underscore its economic significance for Endeavour Mining and for Côte d’Ivoire’s mining sector, contributing substantial gold production and local employment. Future operation will monitor potential acid generation from ore and its impact on process water quality, with mitigation measures to be developed in subsequent phases.

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

Target Commodities: Gold