The Lumwana Project contains two major copper deposits, Malundwe and Chimiwungo, which are structurally controlled shear zone hosted deposits considered to be an end member of Central African Copperbelt class of deposits. These copper + cobalt + gold + uranium deposits are hosted within the Mwombezhi Dome, which is a northeast trending basement dome in the western arm of the Lufilian Arc thrust fold belt.

In Zambia, the Lufilian Arc contains variably deformed and metamorphosed Late Proterozoic metasediments and volcanics of the Katangan Lower and Upper Roan, Mwashia, Nguba, and the Kundelungu supergroups, which unconformably overly the basement. The basement consists of older metamorphosed gneisses, schists, migmatites, amphibolites and granitoids. Subsequent to the deposition of the Katangan sequences, the basin was inverted, deformed, metamorphosed, and uplifted by generally north directed thrusting and folding to produce the late Neoproterozoic – Cambrian Lufilian Arc.

The copper mineralization at Malundwe and Chimiwungo is hosted almost entirely within high grade metamorphosed, intensely mylonitized, recrystallized muscovite–phlogopite–quartz–kyanite schists with disseminated sulphides (typically <5%) dominated by chalcopyrite and bornite which is locally referred to as Mineralized Ore Schist. The distribution of copper mineralization is controlled by visibly identifiable stratabound geology, within which copper grades are consistent. Optimal grade continuity is aligned to an observed north–south stretching lineation.

The copper mineralization at Lumwana is almost entirely disseminated sulphides (typically <5%) dominated by chalcopyrite and bornite with a minor amount of the resource classified as oxide or transition.

The overall strike length of mineralization at Malundwe is approximately six kilometres north-south and up to 1.5 km wide (east-west), predominantly as a single Mineralized Ore Schist horizon. The mineralization outcrops in the east, has an overall gentle dip to the west, and plunges to the south.

The Chimiwungo deposit is partitioned into three bodies by two steep west-northwest trending dip-slip fault zones. The mineralized zones are referred to as Chimiwungo South, Chimiwungo Main (includes the recently discovered Chimiwungo East mineralized shoot), and Chimiwungo North. The mineralization Chimiwungo currently extends up to 1.5 km north-south and 2.8 km in the east-west orientation and remains open to the east and south.

There are two mining areas; Malundwe and Chimiwungo, which are 7 km apart in a direct line. Malundwe was the first pit to be mined, commencing in 2008. However Chimiwungo now contains 93% of the remaining reserves. The Chimiwungo mining area consists of three separate pits; South, Main and East. Malundwe was the first pit to be mined, commencing in 2008. However Chimiwungo now contains 93% of the remaining reserves. The Chimiwungo mining area consists of three separate pits; South, Main and East.

Sulphide copper ore at Lumwana is mined by open pit methods that follow the typical sequence of tasks: grade control drilling, blasthole drilling, blasting, loading by hydraulic shovels (15 m3 and 27 m3 ), and hauling by off-highway trucks (254 t). The mine started operations in 2008, and now mines an average daily capacity of 260,000 t of total material mined. Mining is done primarily by Lumwana personnel and equipment; however production is also supplemented by a contractor with specialized small articulated fleet of trucks to meet pre-stripping requirements, particularly the stripping of weathered material in the wet season. They use 40 tonne capacity Volvo articulated trucks and 90 tonne tracked excavators. The contractors move 45,000 tonnes per day and are scheduled by the Lumwana Mine Engineering Department to coordinate material movements.

There are two crushers; at Malundwe and Chimiwungo South, which have the same setup and similar design. The Malundwe crusher was commissioned at the start of operations in 2008, whereas the Chimiwungo South crusher was commissioned in Q3 2011.

Trucks from the mines can tip directly into a 400t capacity run-of-mine (ROM) dump hopper. The ROM pad accepts ore that cannot be directly dumped into the crusher feed hopper due to blending requirements or capacity constraints. The primary gyratory crusher crushes the ROM ore from a nominal top size of 1,500mm to less than 200mm. Oversize material is deposited on the ROM pad to be further broken by a mobile rock breaker. Crusher product is then conveyed via overland conveyor to a conical crushed ore stockpile with 12 hours live capacity. The Malundwe overland conveyor is 4.5km long, and the Chimiwungo South overland conveyor is 3.5km long.

Stockpiled and crushed ore is reclaimed via apron feeders onto a conveyor belt providing direct feed, at a rate of approximately 3,200t/h, into the 38ft diameter by 18ft SAG mill. The SAG mill trommel undersize discharges into a hopper and is pumped to conventional hydrocyclones, operating in closed circuit with a 26ft diameter by 40ft ball mill. The hydrocyclone overflow, with a particle size distribution of 80% passing 380µm, reports to flotation, and the cyclone underflow returns to the ball mill for further size reduction.

The Lumwana concentrator flow sheet has a nominal design capacity of 25Mtpa.

The flotation plant consists of two parallel trains of rougher/scavenger cells. The rougher/scavenger concentrate reports to the regrind circuit to further liberate the copper minerals. Following regrinding, the concentrate is cleaned in a conventional cleaner/recleaner circuit to reach final concentrate grade. Final concentrate grades of approximately 25% to 33% copper are expected.

Five 17 m3 Dorr Oliver flotation cells are utilized for re-cleaner flotation. The tailings report to the cleaner flotation cells. The concentrate from the re-cleaner flotation circuit is pumped to the concentrate thickener after passing the final concentrate sample analyser and trash screen. The sample analyser determines the pulp density, and the copper, iron, and cobalt concentrations.

Collector, frother, and flocculant are the primary reagents used in the processing plant at Lumwana. A number of ........