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 mineralized zone of Tilwezembe is located in a northeast-southwest anticlinal structural lineament, which extends further to the east where known copper and cobalt deposits exist (Kisanfu, Myunga, Kalumbwe and Deziwa). Strongly brecciated siliceous dolomites and shales of the Mwashya Formation (or R4) dominate with interstitial bands of haematite and oolites. The strata strike almost east-west and dips at about 45° to the south.

Tilwezembe Open Pit (Kananga) The cobalt-rich Tilwezembe open pit operation is located 30 kilometers southeast of Kolwezi.

The historical drilling was undertaken by GCM, and the information was the basis for the first Mineral Resources estimates for Tilwezembe Mine undertaken by SRK. The drilling information included holes on a 25 m spacing within the operational Tilwezembe pit and 100 m x 50 m on Tilwezembe East.

The procedures adopted during the sampling of the cores from Kananga and Tilwezembe are similar.

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

KCC is currently operating the WOL hydrometallurgical processing at their existing Luilu operation. The KCC WOL project is designed to process the mixed ore flotation tails from the KTC plant, as well as the roasted sulphide concentrate, to produce 300 ktpa of copper metal and 30 ktpa of cobalt contained in cobalt hydroxide. Further expansion is planned to achieve cobalt production capacity of 40 ktpa.

Flotation
The flotation circuit consists of two distinct parallel flotation circuits followed by a common cleaner circuit. From the surge tank slurry is distributed to the two flotation circuits via a dedicated pumping system.

The concentrate from the rougher cells 1 will gravitate to Tank TK 035, and then be pumped to Tank TK 059. The concentrate from the respective scavenger cells will gravitate to Tank TK 036, and also be pumped to Tank TK 059. The concentrate from Tank TK 059 will be pumped to the cleaner flotation cells. The tails from the rougher cells wi ........