Project: Gold Mine – Senegal
Location: Senegal
Overview
The Gold Project is located in south-eastern Senegal in the Kedougou region, close to the Gambia River and Township of Mako.
Run of mine ore from open pit mining is primarily crushed and fed to a single stage SAG mill in closed circuit with two pebble crushers and cyclones. A percentage of the coarse cyclone underflow is bled off to be fed to a Knelson gravity concentrator, the tailings of which then report to the mill discharge hopper.
The ores are relatively consistent but display very high competency with very high grinding energy requirements and are extremely abrasive.
The Challenge
The SS SAC circuit was processing 250 t/h on 100% fresh ore. A grinding circuit review was carried out and found that:
Process control and cyclone efficiency could be improved.
Pebble extraction could be increased.
Power utilisation and intensity required optimisation.
With the implementation of these strategies, a potential throughput increase of 6.4%, or 266 t/h, was predicted at P80 of 125 µm.
The MillROC Solution
Recommendations were put in place to achieve the optimised throughput target. Installation of MillROC, MillSlicer, MillStar, FloCEP cyclone distributor and grate modifications. All were implemented by the client and supported by MillROC.
The optimisation plan was split into three phases:
Phase 1 – Stabilisation Control. The engagement focused on coaching to achieve stability, mill density, power draw, cyclone pressure control / circulating load and grind. This included training on using the MillSlicer to optimise impact intensity and mill power draw.
Phase 2 – Optimisation. The second stage focused on implementing the trained philosophies into the MillStar for automated mill control.
Long-term items – Included assistance with implementing the FloCEP cyclone distributor project and input into grate and liner design optimisation.
Outcomes
As of February 2023, all optimisation projects had been implemented.
The circuit averaged 261 t/h, a 4.4% improvement in throughput, while often treating a harder than evaluated blend.
Liner life had increased by 20% as a result of better load control and minor grate design changes.
More stable cyclone operation with minimal cyclone roping and coarse material on the trash screen and in the CIL tanks.
The optimisation is ongoing with further benefits expected.
