The geological setting of the Zambian Copperbelt is unusual compared to other worldwide copper deposits in that it occurs in sedimentary host rocks that have high carbonate content. The presence of dolomite in the geological sequence effectively eliminates any risk of acid mine drainage. The dominant structural feature of the Zambian Copperbelt is the Kafue Anticline, a Northwest — Southeast striking structure, the core of which is comprised of granite, schist and gneiss of the basement complex.

The Konkola Deposit is a very large copper deposit situated on the northern section of the Copperbelt. The Katangan sediments that contain the copper mineralisation are draped around a core of basement rock. Dips are in the range 15-70 degrees. Relatively continuous grades and thickness commonly occur on a regional scale with local variations being due to areas of structural thickening of the Ore Shale Formation and low grade zones resulting from leaching around faulted ground.

Copper mineralisation in the Ore Shale Formation is typically 2-20 m thick, and is also found in its immediate footwall and hanging wall. Economic grades of mineralisation (approximately 4%TCu) are generally consistent within the stratabound deposit and extend over a 7 km strike length at surface, extending to over 10 km at depth (>1,400m). The deposit is open at depth. The orebody thins out at its eastern extremity due to the development of arenaceous facies within the Ore Shale Formation. To the south-east it is cut by the Luansobi fault zone.

Primary mineralisation is mainly of bornite and chalcopyrite with secondary copper minerals being widespread above the 275 m Level, including chalcocite, malachite, chrysocolla, covellite and azurite. Further, general zonation is from chalcocite near surface to pyrite at depth.

Disturbed ground and minor faulting with throws of less than 10 m are present throughout the deposit.

The Konkola deposit is positioned between two major faults; the Lubengele in the north and the Luansobe in the south. These faults form the main hydrogeological boundaries to the deposit.

The Ore Shale Formation is located between three main aquifers:

Hanging wall aquifer located 30 m to 180 m above the Ore Shale;
Footwall aquifer directly on the Ore Shale contact; and
Footwall quartzite 400 m below the Ore Shale.

The hanging wall aquifer contributes 35% of the water in the mine and mainly comprises carbonate rocks, limestones, dolomites and calcareous sandstones and siltstones, while the footwall aquifers provide 65% of the total water inflow and are composed of siliceous rocks: quartzites, sandstones and conglomerates. As a generalisation, the quantity of water inflow to the mine increases with steepening dip of the stratigraphy due to the development of wider fracture zones.

The operating shafts at the Konkola mine are underground mine (No. 1 shaft, No. 3 shaft and new No. 4 shaft, along with a number of ventilation shafts as well as the pipe shaft) and the Konkola concentrators.

The dominant features of the mine are the Kirila Bombwe Anticline in the southeast and the Konkola Dome in the northwest. The ore body in the No. 1 shaft area lies on the southern flank of the Kirila Bombwe Anticline and has an average thickness of about nine metres. The No. 1 shaft ore body generally strikes to the northwest-southeast and dips steeply southwest. It has a strike length of approximately 4,000 metres with an average dip of 50 degrees. The ore body in No. 1 shaft area is traced to 1,800 mtr deep and is open-ended at that depth. The ore body at the No. 3 shaft lies across the axis of the Kirila Bombwe Anticline and has an average thickness of 13 metres. The dips at the No. 3 shaft generally range from 10 degrees to 65 degrees. The ore body at the No. 3 area has been traced to a depth of 1,150 metres where it flattens out and continuing in the neighbouring licence area.

Historically, the No. 1 and No. 3 shafts have been managed as two separate mines. Underground haulage connections between the two mines were developed mainly for cross tramming and de-watering purposes. The separate treatment of the two mines was due to their Ore Reserves being physically divided by the presence of a barren gap in the ore body that extended from the surface down to about 720 metres. Below that level the ore body is continuous along a strike length of approximately 10 km and this large ore body forms the basis of the Konkola Deep Mining Project (KDMP). The total capacity of the Konkola underground mine has been expanded by the KDMP.

Mine developments consist of primary and secondary developments at both the No. 1 and No. 3 shafts. Primary developments involve mining haulages, drain drives, access ramps, footwall ventilation raises and rock passes on main levels. Secondary development includes the mining of drives, crosscuts and raises in ore and waste on the sublevel to prepare the ore body for stopping. The mining operations are constrained by the necessity to de-water from both hanging wall and footwall aquifers at an overall pumping rate of approximately 350,000 m3 per day.

The ore body limits are defined by sampling cross cut as well as diamond drilling on approximately 30 metres by 30 metres pattern. The stope limits are contained within the ore body defined using a 1.0% total copper cut-off. Other stope dimensions are worked out using geotechnical properties of the rocks.

Mining methods employed at the Konkola mine include sub level open stopping, post pillar cut and fill and panel stopping. The total rock hoisting capacity at the Konkola mine is 645 kilo tonnes per month (“ktpm”) which comprises 160 ktpm from the No. 1 shaft, 135 ktpm from the No. 3 shaft and 350 ktpm from the No. 4 shaft. On reaching the surface run of the mine (“RoM”) ore from the No. 1 and 4 shaft is conveyed via conveyor belt directly to the Konkola concentrator and the RoM ore from the No. 3 shaft is transported three km to the Konkola concentrator using 85 tonne off-highway trucks.

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The 6 mtpa Konkola concentrator processes RoM ore sourced from the Konkola underground mine using froth flotation to produce copper concentrate for smelting at the smelter in Nchanga. RoM ore hoisted from the new No. 4 shaft, through the mid- shaft loading station is transported to the plant through conveyor belts.

The 6 mtpa concentrator comprises two streams of 3 mtpa. The nominal capacity of the milling circuit is 6.6 mtpa, which with a 10.0% design allowance yields a maximum milling capacity of 7.3 mtpa.

The crushed RoM ore is fed directly into the concentrator ’s SAG mill with final milling being performed in the Ball mill prior to flotation. The concentrates are thickened and filtered to produce a final concentrate with a grade of approximately 36.0% to 40.0%.

The concentrates are then transported 30 km southwest of Chililabombwe by road to the Nchanga smelter in Chingola. Approximately 60.0% of the residual tailings from the concentrator are thickened and pumped straight to the Lubengele tailings dam situated approximately 4.5 km north of the plant, while approximately 40.0% of the tailings are pumped to the backfill plant to produce backfill for underground mining operation.

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