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.

Mamatwan Mine
The manganese mineralisation at Mamatwan is hosted by the Hotazel Formation of the Postmasburg Group (Transvaal Supergroup) and occurs as stratiform bodies interbedded with banded ironstone formation. This Formation is characterized by three manganese-rich horizons, called the Lower, Middle and Upper Bodies respectively, separated by BIF.

The lowermost of the three units, the Lower Body (LB), is the only unit exposed and currently mined at Mamatwan Open Pit Mine. The Middle Body is poorly developed, often ferruginized, and carries no economic value. The Upper Body (UB) is considered to be potentially economic, with manganese scattered throughout the unit. The Kalahari Manganese Field, with specific reference to the Mamatwan type ore (rich in braunite–kutnahorite mineral assemblages) represents approximately 97% of the total manganese resource in the region.

At Mamatwan Mine the LB is 37.5 m thick on average. It is subdivided into an uneconomic 19.5 m thick upper horizon (the Top Cut) containing ±31% Mn, with a Mn/Fe ratio of 5; a central horizon (the Manganese Cut) which is on average 19.7 m thick and contains ±37.5% Mn with a Mn/Fe ratio of 8.5; and a 6 m thick Basal horizon. These are subdivided into smaller seams (Zones), based on different mineralogical compositions. The Zones are visually distinguishable from each other and are identifiable by a combination of geological logging and chemical analysis. The M, C, and N Zones of the central horizon are high grade while the lower grade material of the Top Cut is represented by the V, W, X, Y and Z Zones. The Basal horizon is low grade and not considered to be potentially economic so is not part of the Mineral Resource.

The ore at Mamatwan consists of banded, very fine-grained braunite-kutnahorite lutite, containing concretionary ovoids, laminae and lenticles of Mn-calcite with which hausmannite is commonly associated. Subordinate amounts of hematite, jacobsite and rhodochrosite are also present. The relatively high Mn/Fe ratio of the economic manganese ore makes it suitable for the production of high manganese (76% Mn) alloys. The relatively high carbonate content of the ore, reflected in the CO2 content of 12 to 16%, makes it virtually self-fluxing.

Wessels Mine
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 Hotazel Manganese Mines (HMM) has two operations, the Wessels high-grade underground mine and the Mamatwan medium grade open-pit mine.

Mamatwan Mine
Mamatwan mine consists of an open pit operation that commenced in 1963. This pit is still operational, and is being extended to the north and west. The current run of mine for Mamatwan mine is in the order of 3 million tons per annum. Manganese ore is sold to both the local and international markets.

Stripping and stockpiling of topsoil and waste rock
Mamatwan mine is a conventional opencast operation in that topsoil and waste rock is removed to uncover the manganese ore body using truck and shovel methods. Topsoil is transported via truck to designated topsoil stockpile areas for later use as part of rehabilitation. Waste rock is stripped and transported to one of the designated WRDs at the MMT. Waste rock is either backfilled into the open pit or used to flatten the slopes of existing dumps.

Access to open cast workings
Ore is drilled and blasted, and hauled using front end loaders and shovels to the "in-pit" primary crusher. Crushed ore is conveyed to a product stockpile area (ROM stockpile) near the mineral processing plant. Excess ore is stored and crushed as required.

In pit crushing and screening
Oversize ore is crushed using a “in-pit” jaw crusher to reduce the size of the ore for further downstream processes. The crushed ore is conveyed to a designated Run of Mine (ROM) stockpile area.

Wessels Mine
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 at Wessels Mine 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.

Mamatwan Mine
The material crushed and screened through a screening and crushing facilities (in-pit crusher, ROM cone crushers, Kawasaki crushers).

Blast-hole material is transported 80 ton rear-tipping trucks or haulers primary crusher (jaw-crusher) for initial size reduction or crushing. This primary crushing step reduces the size of the ore from a maximum rock size of 700mm to 150mm.

Particles with a diameter greater 75mm is removed by scalping screens and allowed it to be crushed by the secondary crushers (gyrating cone crushers – Nordberg crushers).

The 6 to 40mm material is crushed and screened through a tertiary screening and crushing facility (Kawasaki Crushers).

Wessels Mine
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.

Mamatwan Mine
In pit crushing and screening
Oversize ore is crushed using a “in-pit” jaw crusher to reduce the size of the ore for further downstream processes. A primary crusher with a capacity of 650 tph within the pit reduces ore to less than 150 mm. The crushed ore is conveyed over a distance of 1.8 km to the primary stockpile.

Crushing, screening and washing (ore processing)
Ore from the ROM stockpile is conveyed to two parallel circuits comprising scalping screens, cone crushers and double-deck sizing screens and a horizontal dewatering screen at the processing plant.

Lumpy material (– 75 +6 MM) from the processing plant is stockpiled in marked allocated lumpy product stockpile area (Gantry 7) prior to being sent to the load out station using front end loaders. The product is conveyed to railway trucks via the load out section for sale to third parties.

Slimes material from the processing plant is sent to the tailings dam for disp ........