Geometallurgical Characterisation with Portable FTIR: Application to Sediment-Hosted Cu-Co Ores

Abstract

Cobalt (Co) mine production primarily originates from the sediment-hosted copper (Cu) deposits of the Democratic Republic of Congo (DRC). These deposits usually consist of three ore zones with a supergene oxide ore blanket overlying a transition zone which grades into a sulphide zone at depth. Each of these zones display a mineral assemblage with varying gangue mineralogy and, most importantly, a distinct state of oxidation of the mineralisation. This has direct implications for Cu and Co extraction during mineral processing as it dictates which processing method is to be used (i.e., leaching vs. flotation) and affects the performance of these. To optimise resource efficiency, reduce technical risks and environmental impacts, comprehensive understanding of variation of ore mineralogy and texture in the deposit is essential. By defining geometallurgical ore types according to their inferred metallurgical behaviour, this information can serve to classify the resources and improve resource management. To obtain insight into the spatial distribution of mineral grades, it is necessary to develop techniques that have the potential to measure rapidly and, preferably, within the mine at relatively low-cost. In this study, the application of portable Fourier transformed infrared (FTIR) spectroscopy is investigated to measure the mineralogy of drill core samples. A set of samples from a sediment-hosted Cu-Co deposit in DRC was selected to test this approach. Results were validated using automated mineralogy (QEMSCAN). Prediction of gangue and target mineral grades from the FTIR spectra was achieved through partial least squares regression (PLS-R) combined with competitive adaptive reweighted sampling (CARS). It is shown that the modal mineralogy obtained from FTIR can be used to classify the ore according to type of mineralisation and gangue mineralogy into geometallurgical ore types. This classification supports selection of a suitable processing route and is likely to affect the overall process performance.

The applicability of G-BASE stream sediment geochemistry as a combined geological mapping, and prospective exploration tool for As-Co-Cu-Ni mineralisation across Cumbria, UK.

“…As defined in the 2015 Paris Climate Agreement, the goal of societal carbon-neutrality by minimum 2050 requires an increased global production of Plug-in Hybrid Electric Vehicles (PHEV), critical to this being the supply of Energy Critical Elements (ECEs) such as Ag, Al, Cr, Co, Cu, Fe, In, Li, Mn, Mo, Nd, Ni, Pb, V, and Zn (Darton Commodities Ltd. 2020;Hund et al 2020;Dehaine et al 2021;Tabelin et al 2021). Cobalt (Co), in particular, is used in various industries related to the production of renewable technologies including PHEV, Li-Co batteries, and high-strength magnets (Alves et al 2018;Dehaine et al 2021;Solferino et al 2021). There is a current monopolisation of global supplies with 69 % of 2020 global Co mining from the Democratic Republic of Congo (DRC) (Gulley.…”

Indicator Minerals, Pathfinder Elements, and Portable Analytical Instruments in Mineral Exploration Studies

“…Dehaine et al [52] used portable FTIR spectroscopy to measure the mineralogy of drill core samples from the sediment-hosted Cu-deposits of the Democratic Republic of Congo. The type of mineral assemblages and gangue mineralogy will have a bearing on the extraction process (i.e., leaching vs. flotation) to be used for the extraction of Cu and Co. A comprehensive understanding of the variation of ore mineralogy and texture in the deposit is essential in order to optimize resource efficiency and reduce technical risks and environmental impacts.…”