The Chibuluma deposits are SSC deposits located in the Zambian portion of the Central African Copperbelt. The Copperbelt forms one of the world’s largest metallogenic provinces containing over a third of the world’s cobalt mineral reserves and a tenth of the world’s copper mineral reserves.

The copper-cobalt deposits of the Central African Copperbelt are hosted within a strongly deformed, arcuate belt of rocks that extends from north eastern Angola through southern DRC and into Zambia, referred to as the Lufilian Arc.

Mineralisation in both Zambia and the DRC is largely restricted to the Lower Roan or Mines Group, although vein style mineralisation is locally important higher in the succession (e.g. Kansanshi, Kipushi, Dikulushi). Mineralisation in the Zambian deposits is dominantly sulphide, comprising chalcopyrite, bornite and chalcocite, variably accompanied by pyrite and pyrrhotite, carollite, covellite and diginite. Ore grades are commonly around 3% to 4% Cu and 0.1% to 0.2% Co.

Mineralisation in the Chibuluma South orebody is predominantly Cu with very minor Co and is hosted in detrital conglomerates, sandstones and argillaceous siltstones of the Lower Roan Group. The orebody is hosted by a competent quartzite horizon overlain by a sequence of argillites and dolomites of the Upper Roan Group. Mineralisation is hosted in a mineralised quartzite known locally as the Orebody Quartzite (“OBQ”) with the unmineralised quartzite below the OBQ referred to as the Footwall Quartzite.

The Chibuluma South orebody occurs over a strike length of 300 m, dipping at approximately 38° towards the north-west and varies in thickness from a few metres to over 30 m in places for a typical section through the ore body). Drilling has defined the orebody to a maximum depth of 600 m where it pinches out against a basement high. While drilling has closed off the orebody at depth, it is feasible that the ore boby opens up down-dip of the basement high.

Mineralisation occurs as oxide to a depth of 60 m and as sulphides below the 60 m level. Malachite is the dominant oxide mineral while bornite, chalcopyrite and chalcocite constitute the sulphides. Chalcocite is found immediately below the oxide cap in the sulphide zone. Bornite dominates in the thickest and richest central portion of the orebody and is the predominant sulphide mineral with chalcocite below the 400 m level currently being developed by the Mine. Chalcopyrite accounts for approximately 20% of the sulphides and becomes more evident towards the fringes. Pyrite dominates in barren fringe areas.

Copperbelt, oxidation and leaching of copper minerals is common to about 45 m to 60 m from surface, although it may be observed to depths of several hundred metres. The leached zone close to surface is commonly barren or very poorly mineralised. Supergene enrichment below the zone of leaching is highly variable with the main supergene minerals including malachite, chalcocite, cuprite, chysocolla and vermiculite.

Chibuluma Mines Plc operates the Chibuluma South and Chifupu ore bodies.

As Chibuluma South Mine underground operation reached the end of life, underground mine underground operation operations ceased in August 2019 and the Group commenced crown pillar open cast mining.

The ore from the South section is stockpiled on a ramp with a capacity of 20 kt. The ore with a size grading of - 700 mm is fed by front-end loader directly into a jaw crusher. The product from the jaw crusher is –100 mm and is further crushed by the Hazemac impact crusher to a size of 60% -13.5 mm. This product is then deposited on a 6 kt tonne capacity stockpile. This crusher increased the concentrator capacity from 42 ktpm to 48 ktpm. The crusher can be operated in or out of circuit.

A series of conveyors feed a secondary cone crusher (which acts as a standby unit for the Hazemac impact crusher) via a vibrating scalping screen. The scalping screen undersize and the secondary crusher products are fed to a sizing screen which is in closed circuit with a tertiary cone crusher.

The product from the sizing screen is 85% –13.5 mm and is deposited on a 3 kt capacity stockpile. A conveyor fitted with a weightometer feeds a 20 t mill feed bin and two mill feeder conveyor belts fitted with weightometers feed the two ball mills at a similar rate. A cyclone is in closed circuit with each mill.

Ore from the Chibuluma South Mine is treated at the on-site Chibuluma concentrator. Ore is first crushed and milled into a fine powder before being fed into the floatation plant for concentration. At the concentration stage, the ore is mixed with chemicals and introduced to a water bath. Copper sulphides form as a froth at the surface and are skimmed off. The froth is dried and forms a copper concentrate with a grade of 46.0% copper. Trucks then haul the concentrate to CCS, where it is purchased.

The concentrated is de-watered in a thickener and pumped to a filter press. The overflow from the thickener is recycled to the process water tank. Water from the tailings dam is also returned to the process water tank. The fresh water make-up comes from a local stream located 3 km from the processing facility. The concentrate with a moisture content of 10% is deposited on a stockpile.

The crown pillar ore in Chibuluma‘s processing plant has proven to be a huge challenge, ........