South African manganese deposits are currently confined to the Early Proterozoic Transvaal Supergroup, Northern Cape Province. They can be grouped into two major categories:
1. Syngenetic carbonate-rich manganese deposits interbedded with the banded iron formations (BIF) of the Hotazel Formation, colloquially called the Kalahari Manganese Field.
2. Karst-fill type manganiferous material from residual Fe-rich manganese developed in dolomites of the Campbell Rand Subgroup in the Postmasburg Fe-Mn Fields.

The Kalahari Manganese Field is situated within a structural basin, known as the Dimoten Synclinorium, plunging at an angle of 3° to 8° to the north and northwest. It extends from Mamatwan Mine in the south for approximately 40 km to Wessels Mine in the north, with an east-west extent varying between 5 and 15 km.

Local Geology
Wessels Mine extracts high grade (above 47% Mn) manganese ore. The ore is typically coarse grained, shiny, massive or vuggy, with the principal minerals being hausmannite and braunite II (Wessels-type ore), as opposed to primary, lower grade braunite further to the south in the Kalahari Basin (Mamatwan-type ore). The current interpretation is that the Wessels-type ore was formed by hydrothermal alteration of primary Mamatwan-type ore and that the alteration took place along a system of post-Olifantshoek, north-south and east-west striking normal faults.

The massive tabular manganese ore body at Wessels is 300 m below the surface. It is accessed through vertical and twin decline shaft systems and mining uses the mechanized room and pillar method. The vertical shaft is used primarily as a personnel and material hoisting facility while ore is conveyed to surface through the inclined shaft. Both act as intake ventilation shafts.

The ore is blasted and front end loaders, matched with 25 t dump trucks, deliver the ore to underground primary crushers situated in the East and West Blocks. An additional crusher is being installed for the Central Block. Ore is conveyed from the various crushers to a central ore handling system consisting of storage silos close to the vertical and inclined shafts. From here the ore is transported by a cable belt conveyor up the 14 degree incline to the washing and screening plant on surface.

Mining is focused on the Lower Body (LB) and the Upper Body (UB) horizons. Only the LB is currently extracted, with extraction of the UB planned for later during the mine life. Various access points to the UB currently exist due to structural faulting and localized exploratory mining. The mine production is divided into the East, Central, Graben and West Blocks based on structural zones.

Pillar dimensions are 8 m x 8 m in the West and Central Blocks and 6 m x 6 m in the East Block with 8 m wide rooms throughout, to meet geotechnical requirements. The mining height varies from a minimum of 3.5 m to a maximum of 5.5 m, predominantly constrained by equipment operating requirements and physical ore body thickness.

Blasted ore is loaded using Load Haul Dump (LHD) machines onto 25 t articulated trucks which transport ore to a conveyor system in the mine. Primary ore crushing is conducted underground with ore storage in underground silos from where it is transported to surface by conveyor. The current room and pillar mining method at Wessels Mine is conventional and consists of: preparation, drilling, charging, blasting, mucking, cleaning and support. The mining strategy is to block development areas to establish through-flow ventilation and increase flexibility of the various grade products produced. High grade faces are mined, stockpiled and conveyed using timed hoisting schedules.

The mechanised underground mining equipment fleet comprises:
- Haul Trucks – Sandvik and CAT AD30;
- Load Haul Dumpers (LHDs) – CAT R13-1700;
- Roofbolters – Atlas Copco;
- Drill Rigs – Boart Longyear;
- Dozer – CAT;
- Grader – Wright;
- Scaler;
- Light duty vehicles.

The ROM ore is crushed by underground primary crushers to -150 mm size. The ore is conveyed to the plant at surface where a secondary cone crusher reduces it to -75 mm. It is then screened and washed to produce various marketable manganese products. These are stockpiled after the washing plant based on size and grade specifications.