Overview

Deposit type

• Magmatic

Summary:

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.

Mining Methods

• Breast stoping with strike pillars
• ULP / XLP

Summary:

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.

Underground mining occurs via two complexes, namely Tumela Mine (western section of the mine) and Dishaba Mine (north eastern section of the mine)
• The conventional breast mining method is widely used with mechanised mining recently introduced at Tumela 15E
• The ore is scraped into stope ore passes and then hauled (footwall haulages) by battery powered locomotives to the main hoisting shafts
• From surface the ore is transported to the concentrator by rail
• Conventional mining is currently being undertake at the Amandelbult Mine Complex

The Amandelbult Mine Complex currently employs a labour-intensive conventional mining methodology for the mining of its narrow tabular ore body. In 2021 Anglo American Platinum commenced with the implementation of a portfolio of mechanised mining projects as volume replacements for the depleting conventional / modernised investment centres. The development of the mechanised mining knowledge base will be leveraging technical and operational learnings from the Tumela 15E Mechanised project together with industry best practice. The mechanisation initiative was included in the latest business plans, with associated allocation of the relevant budgets to each project.

The mechanisation projects consist of the following four major Capital Projects and associated infrastructure:
• Middellaagte Upper & Middellaagte Lower;
• Tumela 1 Sub Shaft;
• Tumela 15E Extension; and
• Dishaba East Upper and Dishaba East Lower.

Comminution

Crushers and Mills

Summary:

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.

Mainstream inert grinding (MIG) and Ultra-fine grinding (UFG) concentrate regrind mills:
MIG - 4 x IsaMill™M10000
UFG - 1 x IsaMill™M3000

Processing

• Desliming
• Spiral concentrator / separator
• Gravity separation
• Crush & Screen plant
• Electric furnace
• Flotation
• Dewatering

Summary:

Amandelbult complex facility comprises three concentrators with a chrome plant.

The concentrator complex is capable of processing 600 ktpm. The ore undergoes several processes, including milling and concentrating, to extract the target minerals. The concentrate is transported to off-site smelters for further refinement.

Ore mined from the reserves is processed at the AMB Concentrator before being transported to various AAP smelters for smelting and further refining at the Rustenburg Base Metals Refinery and Precious Metals Refinery. The main metal produced is platinum with other metals in the platinum group metal (PGM) suite that being chrome, rhodium, palladium, ruthenium, iridium, osmium, and including gold. Base metals produced, include copper, nickel and cobalt.

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 average moisture content of 16-17% by mass is delivered by road in flexi-side tippers or containers, and offloaded in the concentrate-receiving shed. Slurries with a solids content of 50-60% are pumped or delivered by tanker to the Waterval Complex Concentrate Handling plant (WCCH) for dewatering.

In the flash drying process, moisture is removed from the wet concentrate, producing a dry furnace feedstock (<0.5% H2O). The energy for the process is provided by burning coal in a fluidised bed (silica sand) combustor known as a hot gas generator (HGG).

The two electric furnaces are of Hatch design, with a rated transformer capacity of 39 MVA (34 MW maximum or 30 MW nominal design), and a design operating factor of 90%. The rectangular furnaces have internal dimensions of 8.0 x 25.8 m, and the calculated power flux at nominal design is 146 kW/m². The shell is constructed from refractory bricks held together by a precision-designed tension system.

Waterval furnace matte (WFM) is tapped into matte ladles and transported by crane to one of two granulation stations. The ladle is placed on a hydraulically driven tilter that pours the matte into a granulation launder at a predetermined rate. The launder discharges above a stream of granulating water that shearquenches the matte, forming fine particles suitable for dry feeding into the ACP converter.

The slag-cleaning furnace (SCF) is a 12 m diameter round furnace, designed by Pyromet, rated at 30 MVA (23 MW). Three Söderberg electrodes, each 1 400 mm in diameter, deliver power into the bath at currents up to 80 kA. The high currents are required due to the high conductivity of the slag. The resulting high slag temperatures led to the design choice of water-cooled copper sidewalls in the form of Pyromet Maxicoolers. This maximises energy removal, and eliminates the need for annual refractory repairs.

The flotation circuit consists of two 30 m³ cascading Outokumpu tank cells, followed by 14 flotation cells, currently functioning as a single rougher bank. Concentrate is pulled from each of the two tank cells and every flotation cell, then sent to the flue dust thickener. Tailings from the flotation cells are pumped to a tailings dam.

Chrome recovery plant
The plant has two modules, each employing a multi-stage configuration of separators and spirals. It produces two final chromite concentrates, one a metallurgical grade concentrate and the other a chemical grade. The chrome content of the concentrates is approximately 42 %. The two concentrates are pumped to their respective stockpile areas via their own dewatering separators. At the stockpile facility, the chromite is loaded onto trucks (for delivery to domestic customers) or rail wagons (for delivery to international customers via Richards Bay).

The chrome-silica cyclone underflow from the two UG2 plants serves as the dedicated feed stream to the chrome recovery plant and is pumped to two agitated feed surge tanks. From the surge tanks the slurry is delivered to desliming/separator cyclones located prior to the spirals circuit. The cyclone underflow then reports to the spirals circuit by gravity feeding. The spiral nests have been arranged to ensure optimum and equal feed distribution between all individual spirals starts. Where possible, the various stages of rougher, cleaner and recleaner spirals are stacked vertically above one another to maximise gravity feed arrangements to each section.

Water Supply

Summary:

Process Water
The required water will be sourced from the chrome recovery plant process water storage tank. There will not be a need for top-up water during normal operation.

Potable Water
Amandelbult Mine Complex sources most of its potable water from Magalies Water via the Vaalkop Reservoir A 3.5 Ml/d reverse osmosis treatment plant at Dishaba shaft treats water removed from underground to potable standards for domestic purposes at the shaft areas, and a number of other destinations.

Pipeline
As part of the Dishaba East Project there is various surface infrastructure which support the underground mining.

Surface mine water storage dams:
The existing 2 ericson dams will be refurbished to supply water via two separate 250mm diameter pipeline to the adit, before going underground. The length of the pipeline will not exceed 150m, prior to going vertically down the shaft to the relevant station.

Water from underground will be treated and pumped to surface to these ericson dams. Any overflow from these dams will be pumped to the 49E turf overflow dams as is currently practiced, for re-use at Dishaba Mine.

Active Dewatering storage dams: Clear fissure water at source will be pumped from underground to surface into 2 new 4,0m diameter Ericson dams. This water will be used where cleaner water is required, e.g., at the concentrator.

Potable water supply: A 100mm diameter pipeline with a length of 800m, will be installed from the nearby shaft area to the project area.

Tumela 15E Extension Project associated surface infrastructure
Water Handling
Clear water supply to underground
Two ericson dams will be installed on surface to supply water to the underground operations through a 250mm diameter pipeline. The pipeline above ground will not exceed 150m in length, prior to going down the shaft to gravity feed the water

Underground water storage dams
Water from underground will be pumped to surface, and discharge into the two off settler water dams. Any overflow from these dams will be pumped to the TSF overflow dam via two 200mm pipelines with a length of 1500m.

Potable water supply
In order to provide the project site with potable water, a 100mm diameter pipeline will be constructed. This pipeline will tie in to the existing pipeline located at the nearby living quarters and will have a length of 800m.

Tumela 1 Sub Shaft supporting surface infrastructure
Water Handling
The Tumela 1 Sub Shaft will use the existing two ericson dams. A new pipe will be required to feed the mine service water, via gravity, from the ericson dam to the Million Dollar Dam. The pipeline will have a diameter of 200m and a length of 245m.

The existing Million Dollar Dam will be rehabilitated and re-lined for use as storage of excess mine service water from the Ericson dams. A new water pump station will need to be developed as well as a new pipeline from the Million Dollar Dam to the Zero Dam. The Pipeline will have a diameter of 300mm and a length of 7 km.

Potable water will be piped to all downcast ventilation shafts, diesel, emulsion and shotcrete/concrete plant sites within Tumela 1 Sub Shaft. This pipeline will tie into the existing line which services the existing refrigeration plant and will routed along the existing services corridor up. It is anticipated that the pipeline will have a diameter of 250mm and a length of 1500m.

Services at the general buildings
In order to accommodate the Tumela 1 Sub Shaft general buildings a new wastewater drainage pipe will be required. It will route along the existing gravel access road from the 28W RB terrace down and will tie into the existing wastewater pipeline at Tumela 1 Shaft. The pipeline will have a diameter of 200mm and a length of 390m.

Raisebore Shaft (15 Level) and associated surface infrastructure. Water services all pipelines will be approximately 2.2 km.

Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Acting General Manager	Charl Engelbrecht		Mar 11, 2024
Health, Safety & Environment Manager	Alwyn Smit		Mar 11, 2024
Production Manager	Solly Khumalo		Mar 11, 2024
Sr. Engineering Manager	Willem van Loggerenberg		Mar 11, 2024