The mines Tumela and Dishaba are forms part of the Amandelbult section and fully developed situated on the north-western limb of the Bushveld Complex.The mining occurs on both the Merensky Reef and the UG2 Reef horizons.

THE BUSHVELD COMPLEX
Formed over 2 billion years ago from multiple injections of magma into the earth’s crust many kilometres below the surface, the Bushveld Complex is geologically unique due to its size, uniformity of its layering and extent of known mineral content. This saucer-shaped intrusion is over 350km wide, 250km long and up to 12km thick. Over time, the rim of the intrusion has been exposed by erosion, revealing three separate main segments known as the Western, Eastern and Northern Limbs. The Western Limb is split into two lobes (north-western and south- western) by the Pilanesberg complex, a remnant of an alkaline volcanic plug intruded into the Bushveld Complex about 1,250 million years ago. The Eastern Limb is split into two lobes (north-eastern and south-eastern) by the north- east trending Steelpoort fault. The exposed segments exhibit layering of pyroxenites, norites, gabbros, anorthosites and chromitites and this layering occurs across the entire extent of the complex. Within the layers, mineralisation is found in specific horizons containing chromium, iron, titanium, vanadium, nickel, copper and PGM.

The Bushveld Complex comprises three main suites, namely the Rooiberg Group, Lebowa Granite Suite and Rustenburg Layered Suite. The Rustenburg Layered Suite comprises four major subdivisions: the Upper Zone, Main Zone, Critical Zone and Lower Zone. Economic concentrations of PGMs occur mainly in three distinct units within the Critical Zone: Merensky Reef; Upper Group 2 (UG2) chromitite; and Platreef. The Merensky Reef and UG2 Reef occur around the Eastern and Western Limbs of the complex, while the Platreef is found only along the eastern edge of the Northern Limb.

The Merensky and UG2 reefs are narrow tabular orebodies that extend laterally over hundreds of square kilometres, resulting in extensive Mineral Resources.

The Merensky Reef
The Merensky Reef has been the principal source of PGM since it was first mined in 1925. The reef contains economically important PGM and base metal sulphide Mineralisation. However, with the depletion of shallow Merensky Resources, the UG2 Reef, which is found at a minimum vertical distance of 12m to 400m below the Merensky Reef, depending on location, has grown steadily in importance to the point where it now accounts for most of the platinum- bearing ore processed in South Africa.

The Merensky Reef is extensively well developed in both the Eastern (EL) and Western Limbs (WL) of the Bushveld Complex. The reef is well defined and typically consists of a pegmatoidal feldspathic pyroxenite layer, bounded on the top and bottom by thin chromitite layers (stringers) that have thicknesses ranging from 5mm to 20mm. Mineralisation of the reef generally occurs in the pegmatoidal feldspathic pyroxenite and, to a limited extent, in the hanging wall and footwall, with highest PGM concentration peaking at the chromitite stringers.

In the WL, the Merensky Reef dips in an arc ranging from 18º to 27º south-easterly direction in the Amandelbult area and at 9º to 12º northerly direction in the Rustenburg area. It has a variable reef thickness ranging from 1cm (Contact Reef facies) to >2m, over large areas. At Amandelbult complex in particular, the reef comprises up to five different facies. Each facies type exhibits unique geomorphological, geochemical and mineralisation characteristics and plays a fundamental role in geozone delineations and Resource and Reserves widths. In the EL, the Merensky Reef is slightly thicker and dips at 8º to 18º in a south-westerly direction.

The UG2 Reef
The UG2 Reef, which is consistently developed throughout the EL and WL, is rich in chromitite, but with lower gold and base metal content compared to Merensky Reef. In the WL, the UG2 Reef occurs between 12m and 150m vertically below the Merensky Reef and dips at 18º to 27º in a south-easterly direction (Amandelbult area). In the EL, the reef occurs between 120m and 400m vertically below the Merensky Reef and dips at 8º to 18º in a south- westerly direction.

In the WL, the UG2 normally comprises a 0.6m to 1.0m main chromitite band overlain by three chromitite bands (UG2 leaders) varying in thickness from 5cm to 30cm, separated by feldspathic pyroxenite. The immediate footwall of the UG2 is usually a pegmatoidal feldspathic pyroxenite, which varies in thickness from a few centimetres to over 1m. The separation distances between these UG2 leader chromitite bands and the UG2 main band has important implications for geotechnical considerations for mining.

In the EL, the UG2 normally comprises a main chromitite band varying in thickness from 0.3m to 1.0m, overlain by three or up to four chromitite stringers varying in thickness from 2mm to 1cm. The immediate footwall of the UG2 is usually a pegmatoidal feldspathic pyroxenite, which varies in thickness from a few centimetres to over 1m. The separation distances between these UG2 hanging wall stringers has important implications for geotechnical considerations for mining.

In the EL south of the Steelpoort fault, UG2 chromitite is an amalgamation of UG2 main chromitite with the leader chromitite unit, the two usually indistinguishable but may be separated based on their Pt/Pd ratios varying in thickness from 0.60m to 2.25m (averaging 1.20m). This is overlain by a poikilitic feldspathic pyroxenite parting varying in thickness from millimetres to 15m and averaging 1m. This parting is overlain by three chromitite bands (up to 20cm), separated by poikilitic feldspathic pyroxenite and pegmatoidal pyroxenites commonly referred to as the ‘triplets’ with an average thickness of 80cm.

The complex has two mines (Tumela and Dishaba) and three concentrators with a chrome plant. Current working infrastructure has five vertical and seven decline shaft systems to transport rock, employees and material, with mining on the Merensky and UG2 reef horizons. The operating depth for current workings runs from surface to 1.3km below surface.

The primary mining method used at Amandelbult complex is scattered breast mining for both Dishaba and Tumela mines.

Conventional scattered breast mining is preceded by haulage development below reef, parallel to strike. Access to the reef horizon is developed by means of south or north crosscuts. On-reef true dip raises or winzes connect to cross-cuts on different levels by means of step overs and travelling ways. The ore passes are generally done by inverse drilling (from the reef horizon down to the crosscut). Modernised equipment is being rolled out on the stoping horizon to address safety and efficiency concerns, including the introduction of cycle mining, split panels utilising throw blasting and water-jet cleaning to eliminate the use of scraper winches.

Extra-low profile (XLP) mechanised mining method is being implemented at the 15E dropdown project area since inception in 2019. The XLP mechanised mining is an underground mining method designed to exploit narrow reef orebodies (1.2m to 1.7m width) with a dip less than 22°. It maximises reef extraction by placing the primary development (main infrastructure) on reef. A constant production is achieved by coordinating XLP and low profile (LP) equipment to continuously feed the conveyor belt system.

The Tumela Mine is situated in the province of Limpopo in South Africa, between the towns of Northam and Thabazimbi, within the North-western Limb of the Bushveld Complex. The mine operates under a mining right covering a total area of 110 km2.

The current working mine infrastructure consists of three vertical and four decline shaft systems to transport rock, men and material. The mining occurs on both the Merensky Reef and the UG2 Reef horizons, and the mine is subdivided into two production areas, namely the Tumela lower mine and the Tumela upper mine. The predominant mining layout is conventional scattered breast mining with strike pillars. The operating depth for the current workings is between 180 metres and 895 metres below surface.

Dishaba Mine is situated in the province of Limpopo in South Africa, between the towns of Northam and Thabazimbi, and forms part of the North-western Limb of the Bushveld Complex. The mine operates under a mining right covering a total area of 31 km2.

The mine’s infrastructure consists of one vertical shaft, one raise bore and four decline shafts. Dishaba mines on both the Merensky Reef and the UG2 Reef horizons, and the mining layout is scattered breast mining with strike pillars. The operating depth for the current workings is between 30 metres and 1,250 metres below surface.

Slag Milling
The granulated six-in-line and SCF slag are separated from the bulk of the granulating water by rake classifiers. Classifier product is conveyed to the horizontal dewatering screens, and the dewatered slag stored in the slag mill silo, while classifier overflows are pumped to dedicated thickeners for further treatment.

Slag is fed from the silo to a ball mill with a closed-circuit cyclone to achieve a tank cell flotation feed with a particle size of 60 to 75% passing 75 µm. The design mill feed rate is 100 t/h, resulting in a residence time of approximately 13 minutes in the flotation circuit. The current feed rate varies from 60 to 70 t/h.

Amandelbult complex facility comprises three concentrators with a chrome plant.

Concentrator complex
Mined ore from the shafts at RPM – Amandelbult section are hoisted to the surface and trammed separately to the two rail receiving bunkers, from where the ore is stored at the Concentrator. The refined ore is then transported by rail to the Waterval Smelter in Rustenburg for processing and further refining.

The smelter objective is to process wet concentrate to produce crushed, slowcooled, sulphur-deficient nickel-copper matte rich in platinum group metals, gold, and base metals for despatch to the Magnetic Concentration Plant at the Base Metals Refinery.

Wet concentrate is dried, then melted in electric furnaces, and excess iron sulphides are removed in the ACP converter. A slag cleaning furnace treats gangue from the converter, while a slag milling and flotation circuit treats the slag from the electric furnaces.

Wet concentrate with an ........