Abstract:
Geometallurgy provides a platform for cross-functional teamwork between geology and
metallurgy, providing better inputs to mine planning and strategic decision making.
Understanding variability in the orebody enables optimum operational designs and
extraction methods that maximize value recovery. This research focused on the
geometallurgical study of samples from seven potential orebodies in south-western Mali
namely Fresh 01, Trans 01, Trans 02, Lower SAP 01, Lower SAP 02, Upper SAP 01 and
Upper SAP 02. The study was conducted using X-ray Diffraction (XRD), fire assay/Atomic
Absorption Spectrophotometry (AAS)/Inductively Coupled Plasma (ICP) for elemental
analysis, Bond work index, abrasion analysis, gravity concentration and cyanide gold
extraction with and without carbon.
The gold assays were in the range of 0.36 g/t to 2.77 g/t with Fresh 01 being the lowest and
Lower SAP 02 as the highest. The major gangue minerals observed include quartz, dolomite
and montmorillonite. The work indices (BWi) of the ore types ranged from 5.6 to 13.3 kWh/t
and abrasion (Ai) ore parameter ranged from 0.4 to 1.8. Sample Trans 02 gave the lowest
grindability values. Gravity concentration gave concentrate grades between 5.3 g/t to 66.5
g/t and recoveries between 22% and 46%. Gold extraction by cyanide leaching was between
90% and 97%. Increasing cyanide concentration from 250 ppm to 500 ppm did not result in
increased gold extraction. Overall gold recoveries were between 92% and 98%. Lime
consumption was in the range of 1.5 – 3.5 kg/t (1.3 – 2.7 kg/t calcium oxide equivalent).
Cyanide consumption was between 0.19 kg/t and 0.28 kg/t when concentration was
maintained at 250 ppm. The geometallurgical model shows that the best blend had a grade
of 2.09 g/t, Bond work index of 10.0 kWh/t and recovery of 97.8%
