The Great Dyke of Zimbabwe developed as a series of initially discrete magma chamber compartments which coalesced as the chambers filled. The Great Dyke has been sub-divided into five sub-chambers, namely the Wedza, Selukwe (Shurugwi), Sebakwe, Darwendale and Musengezi sub-chambers. The stratigraphic units in each sub-chamber are classified into the ultramafic (lower) and the mafic (upper) sequence. The ultramafic rocks are dominated from the base upwards by dunite, harzburgite and pyroxenite, while the mafic rocks consist mainly of gabbro and gabbronorite. Thin layers of chromitite occur at the bottom of cyclic units throughout the ultramafic sequences. The PGM-bearing horizon is known as the Main Sulphide Zone (MSZ), which is part of the lower sequence and is located below the contact with the mafic sequence. The MSZ is located in the P1 pyroxenite, from 5m to about 50m below the ultramafic/mafic contact. The MSZ is a continuous layer, 2m to 10m thick, and forms an elongated basin. The Zone strikes north-northeast, dips between 5° and 20° on the margins, and flattens towards the axis (centre) of the basin. Peak base metal and PGM values are offset vertically with palladium peaking at the base, platinum in the centre and nickel towards the top. Visual identification of the MSZ is difficult; therefore, systematic monitoring of the reef using various sampling methods is needed to guide mining.

Mining occurs in areas where the dip is less than 9°, which are referred ........

The schematic of the Zimplats operation cuts obliquely across the 2m to 10m thick platinum-bearing MSZ orebody with an approximate northnortheast strike distance of 16km at Ngezi in the south, where the Mupani, Bimha, Mupfuti, Rukodzi and Ngwarati portals are located.

Rukodzi Mine closed operations in June 2022, and the teams were deployed to Bimha and Mupani mines

The development of Mupani Mine, a replacement mine for depleted Rukodzi Mine and Ngwarati Mine which depletes in FY2025, is progressing well and on schedule. The upgrade of Mupani Mine from the current design capacity of 2.2Mtpa to 3.6Mtpa to replace part of the tonnage contribution from Mupfuti Mine on depletion in FY2027 was approved. The mine is scheduled to reach production of 2.2Mtpa in September 2024 (full replacement of Ngwarati and Rukodzi mines) and full production of 3.6Mtpa in August 2028.

The upgrade of Bimha Mine from the current design capacity of 2.0Mtpa to 3.1Mtpa to replace part of the tonnage from Mupfuti Mine which will deplete in FY2027 is progressing well and on schedule. The upgraded Bimha Mine is expected to achieve full production of 3.1Mtpa in FY2023.

Mining Method
A mechanised bord and pillar mining method is employed to extract ore from stopes whose nominal stope width is 2.5m. Mine access is through declines which are generally located centrally in each Mineral Resource block. Any asymmetry is accounted for in the mine production schedul ........

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Zimplats has in place two operating flotation plants at Ngezi Mine and the Selous Metallurgical Complex (SMC), and a smelter at the SMC.

Ore from the mines is processed by two concentrators (at Ngezi and SMC). The concentrator at Ngezi has two similar modules which have a capacity of 2.1Mtpa each, and makes up a total of about 4.2Mtpa. The SMC concentrator has an upgraded design capacity of about 2.4Mtpa.

Additional milling capacity at the Ngezi concentrator site will be availed during the year as a new 0.9Mtpa concentrator module to treat excess ore from the mines is currently under construction and will be commissioned in the forthcoming year.

Approximately one-third of the mined ore (2.4Mt) is transported by road trains to the concentrator at SMC. The rest is transported by an overland conveyor to the concentrator modules at Ngezi. Concentrates from both the Ngezi and SMC concentrators are then smelted in an arc furnace and converted to matte at SMC. ........