Dynamic modelling and optimisation of carbon management strategies in cil: A case study of new liberty processing plant (Liberia)

This thesis presents the Dynamic Modelling and Optimization of Carbon Management Strategies in the gold mine of the company Avesoro Resources in its New Liberty Process Plant, Liberia, which is the subject of this specification aims to increase its gold production and improve the quality of operations in this sector. The primary aim of the model is to investigate different carbon management strategies of the Carbon in Leach (CIL) process. It was provided more control and monitoring means the operations in the said sector. This study was conducted in two parts: Mineral Processing and Metallurgical tests and Optimization and Stimulation of Carbon in Leaching Process. The mineral processing and metallurgical testing were deal with test work samples and leach optimization test. This aims to know the optimization of the leach and grinding test work. The optimization and stimulation of carbon is an important step in gold processing that involves simultaneous adsorption and leaching. The focus of this part was to study the effect of operating parameters like cyanide concentration, pH, oxygen concentration and mean particle diameter on the overall efficiency of CIL circuit. A dynamic model based on first principles was developed for the entire CIL circuit. Leach test at pH 10.50 and different cyanide dosages: it was observed that the recovery of leach at 0.70 kg/ton in comparison to 1.20 kg/ton yields 81.27% and 78.77%, respectively. Test conducted at 1.20 kg/ton had a cyanide consumption of 0.96 kg/ton when comparing it to 0.37 kg/ton of test at 0.70 kg/ton NaCN dosage. The Dissolved Oxygen before and after leach test were below 6.00 ppm. Under leach test on fresh ore at pH 9.50 and 10.00 and 1 kg/t NaCN: it was concluded that after the test the +106, and +75 microns there is a certain degree of locked gold. Above all the gravity recoverable gold when present on a sample will always have a slow reaction kinetics and therefore residence time is essential during leaching. The test residue is high due to locked gold inside coarse material. The cyanide consumption is lower as compared to the main plant trends due to the fact that gold that was available was not in contact with cyanide. From SIMCIL data on comparing the first baseline modelled profile and average plant profile, gold on carbon (not full GIC of gold on carbon/solution/solids) but of course almost all the gold is on the carbon. The full GIC was calculated and shown in the model. The elution frequency column provides elutions/day and elutions/week. Locking all scenarios, with the respect to carbon distribution. We generally found that even carbon distribution (same mass of carbon mass in each tank) was given a solution loss similar to or better than uneven profiles and has the advantage of simplicity.