The copper-cobalt minerals hosted in rocks of the Neoproterozoic Katangan Basin in the Central African copper belt metallogenic province of the DRC are a classic example of (low energy) sediment-hosted stratiform copper (SSC) ore system deposits. These deposits are economically significant, as they account for approximately 25% of the world’s copper production and known Mineral Reserves being second only to porphyry copper deposits in terms of copper production and the most important global cobalt resource.

The copper-cobalt deposits contained in a sedimentary series of rocks are known as the Mines Group in the Katanga sequence and the Roan Group in Zambia. The sediments are shallow-water shales, dolomitic shales, reefal dolomites and possible evaporitic lagoonal mudstones, formed on a platform marginal to a subsiding basin. The rocks are exposed in a series of tightly folded and thrusted anticlines and synclines, which generally trend east-west or southeast and are often overturned to the north. In spite of this deformation overprint, the mineralized zones, although sometimes lenticular along strike and down dip, as well as showing local diapiric forms, display remarkable large-scale continuity within the Mines Group.

The Mashamba East has an intact succession of Series de Mines lithologies, which host the copper and cobalt mineralization. Structurally, the lithologies of the Mashamba East strike to the northeast and dip 20° to the northwest in the west ........

The LOM Mineral Reserve estimate for the KOV and Mashamba East OPs are based on conventional load and haul OP operations which were informed by LOM plans created from first principles.

A cut-off grade of 0.65% TCu was applied at the Mashamba East OP. The basis of the cut-off grade estimation is to determine the break-even cost based on selling, processing and royalty cost. The cut-off grade considered revenues generated from copper and cobalt with the appropriate processing recoveries applied. An average of 7.9% dilution is applied on SMU basis.

The pit optimization completed for the 2016 PFS is still considered current, and as a result no further pit optimization work was done for the Mashamba East OP during the subsequent planning cycles. The overall final pit slope angles of 25° and 40° were applied in the Southern and Northern portions of the pit. Mining and processing costs are inclusive of sustaining capital and are based on the 2016 assumptions used in PFS at that time.

The mixed ore milling consist of CM1 and BM1 (or CM2 and BM2), CM5, CM6 and BM6, CM7 and BM7 milling circuits.

The CM1/BM1 (or CM2/BM2) mills are operated in a closed circuit with a common cyclone clusters. CM5, CM6/BM6 and CM7/BM7 also have the same arrangement. All circuits will produce a grind of 80% -150 µm from a feed with an F80 of 150 mm. BM1/BM2, CM5, BM6 and BM7 operate with a ball load of up to 35%.

The feed to each mill circuit is measured and recorded using a weightometer installed on each AG or SAG mill feed conveyor. Process water, together with the crushed ore, is added to each AG or SAG mill to achieve a slurry solids content of 75% by mass within the mill. Scats conveyors are installed at the discharge of CM5, CM6 and CM7 to remove material from the milling area to a dedicated stockpile outside the building.

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