Processing Study and Circuit Design for Gold in Gabon, Central Africa

An existing processing unit recovering placer gold was losing significant gold due to fine gold grain size. Geovale conducted detailed exploration and established geological resource for commissioning of the processing circuit and also our Process Engineer studied the function of the existing unit and identified the problem areas. Geovale carried out a fresh processing study and circuit design for Gold in Gabon and helped the client to set up the new unit.

Geovale carried out processing studies in great detail by adopting the following approach:

• Bulk sampling for metallurgical recoverability tests.
• Designing an appropriate processing circuit for the alluvial gold to optimize gold production.
• Assisting client in vendor selection and procurement of the equipment for processing according to the client’s budget.
• Complete supervision of erection and commissioning of the processing circuit at mining site.
• Testing of the processing circuit in operation and optimization.

Several challenges were faced during commissioning of the Chinese manufactured gravity based Knelson concentrator at the mine site. Each of the constraints were systematically addressed by the Geovale site team:

• Early malfunctioning of various accessories and elements of the processing circuit. These were addressed by thorough auditing, various trials and calibration processes.
• Due to high variability in gold grades and nugget effect in the alluvial materials being fed to the processing circuit, the initial gold recovery was unsatisfactory. Hence, systematic testing of different ROM material and feeds/rejects were done to establish the optimum feed grade and recovery through different stages of the processing circuit were carried out.
• Detailed QAQC protocol/SOP for the processing circuit was prepared and handed over to the client to optimize the gold production.
• Comprehensive training and handholding of the client’s team was done after post-commissioning supervision.

All the challenges and constrains were addressed and Geovale accomplished the entire project within a timeline of 1 year.