The Kansanshi Cu-Au deposit located in the Domes region of the North West province of Zambia is characterised by structurally controlled high angle veins and associated alteration halos. The northwest trending Kansanshi antiform flanks the Solwezi syncline to the north and hosts the Kansanshi deposit and consists of tillites and metasedimentary rocks. Mineralisation is associated with Neoproterozoic Pan African deformation events experienced during the formation of the Lufilian fold belt; however recent findings confirm that structures in the form of reverse and normal faults and drag folds are critical controls on mineralisation within the deposit, Main pit in particular. Low angle faults occurring below the current pit are believed to have served as major fluid pathways during mineralisation. Age dating data from the Kansanshi deposit suggest that mineralisation took place between 512 and 503 Ma indicating that the event was associated with metamorphism. Two types of alteration are dominant within the Main pit (Kansanshi deposit) with the type and intensity of alteration being largely controlled by lithological units. Albite alteration occurs dominantly in phyllites and schists whereas dolomitisation is prevalent in calcareous units. Alteration is associated with mineralisation, and therefore is used as a condition for predicting vein or disseminated mineralisation. The high Au tenor at Kansanshi can be attributed to gold grains occurring in association with melonite (NiTe₂) and microfractured pyrite intergrown with chalcopyrite in sulphide and quartz dominated veins and veinlets. Analysis of gold grade distribution within the Main pit shows a clear concentration of the element along the major north-south trending structures like the 4800 and 5400 zones, possibly through supergene enrichment in the oxide-transition-sulphide zones. It is imperative that exploration for Kansanshi-type deposits will require geochemical and geophysical studies, understanding of the geology of an area to identify the three lithostratigraphic units (red beds, evaporites and reducing strata).

Kansanshi mine sulphide ore circuit did not achieve target flotation recovery in 2016, hence it was deemed necessary to carry out a research aimed at optimizing this circuit. The objective of the research was to optimise the Kansanshi milling and flotation circuit processing a copper sulphide ore. In line with this, samples were obtained around the circuit and processed in the laboratory for moisture content, slurry concentration, particle size distribution, and flotation response. This information was then used to build a computer-based model of the Kansanshi milling and flotation circuit. This was done in MODSIM®, a software package specialising in the design and simulation of mineral processing operations. After careful appraisal, appropriate models were selected for the semi autogenous grinding (SAG) and ball mills, SAG mill discharge screen, hydrocyclones, pebble crusher, and the flotation cells. The calibrated model was then used to simulate the effects of key operating parameters on flotation recovery. Analysis using the attainable region technique revealed that the SAG mill feed-rate should be adjusted from 1719 tph to 2090 tph. This would lead to a better utilisation of the pebble crusher that can process 358 tph of pebbles from the current 198 tph. From the simulation work, it was established that rougher flotation recovery can be improved from the current 80.0 % to 82.3 %. The technoeconomic benefits of the proposition are yet to be investigated. Findings from the research concluded that the milling circuit optimum operating parameter; which generated a final product falling predominantly in the range - 150 +38 μm were SAG and ball mills conditions of ball sizes 200 and 40mm respectively, ball mill ball filling 32% and rotational speed between 75 and 80% for both SAG and ball mills. The optimum hydrocyclone feed slurry concentration was found to be 62% solids. Additionally, the SAG mill discharge screen aperture size of 6 mm was the optimum. It must be noted that slurry concentration did not show any impact on both the SAG and ball mills performance. The SAG mill ball filling did not show any significant improvement on performance. / College of Engineering, Science and Technology / M. Tech. (Chemical Engineering)