Design of a Tailings Storage Facility at Okouma Mine, Gabon, 2025
Detailed Engineering Design , Hazard Assessment and support services
Project Overview
As part of the operations at the Okouma manganese mine in Moanda, Comilog is developing industrial ponds for the storage of slurry tailings using mined-out pits as containment structures.A scoping study was carried out to identify the most suitable locations for these ponds within the Okouma mine, leading to the construction of the first three facilities. Mecater was subsequently commissioned to conduct the preliminary engineering design and the hazard assessment for the fourth pond, BS04.
The project involves the pumping of sludge (industrial waste generated by the washing plant) to storage basins. In these basins, the sludge settles while clarified water is recovered and reused by the washing plant.The clarified water is collected through a pipeline system connected to a pumping station, which returns the water to the washing plant. At the end of the site’s operational life, landscape restoration will be carried out.
Key data
Footprint: 22 ha
Storage capacity: 12,29 Mm3
Material: Wash plant sludge (dry solids content: 29%; particle size <100 µm)
Heigt max.: 12 m
Storage period: 14 months
Scop of work
- Selection of potential sites for future pond construction
- Geotechnical study: stability and settlement assessment
- Optimization of discharge points to enhance sludge consolidation during operation
- CapEx/OpEx estimates for dike construction
- Verification of pumping capacity from the washing plant to the basin
- Design of the clear water pumping system to the washing plant
- Site restoration and landscape rehabilitation at the end of the site’s operational life.
The industrial basin concept is based on:
- Low-cost storage of industrial waste (€1.50/m³)
- Recovery of treated water for reuse in the production process
- Landscape rehabilitation of mined quarries