Overview

Deposit type

• Magmatic

Summary:

The mine exploits the Platreef, the primary PGM-bearing horizon developed in the Northern Limb of the Bushveld Complex. The reef averages 150m in thickness, with a prominently top- loaded grade profile, hosting optimal Mineralisation in the upper 30m to 40m of the reef package.

The Platreef is developed in the Northern Limb of the Bushveld Complex and can be described as a multiple-pulse mafic magmatic horizon, dominantly pyroxenitic in composition. It averages 150m in thickness, with a prominently top-loaded grade profile, where the optimal Mineralisation is located in the upper 30m to 40m of the package and strikes ~north-south, dipping at an average of 40° to 50° to the west.

In comparison to the Merensky and UG2 reefs, the Platreef is a far thicker and more variable orebody, typified by extensive contact with metasedimentary and granitic floor rocks and assimilation of footwall fragments. The variability of lithology and thickness along strike is attributed to underlying structures and assimilation of local country rocks. This assimilation ranges from shales and banded ironstones in the south, through to dolomites in the centre of the mining area, to granites in the northern portion of the property.

Carbonate floor rocks incorporated into the basal Platreef have been altered to mineralised parapyroxenites and calc-silicates formed during extensive syn-magmatic interaction with high-Mg silicate melts. Towards the north, where the Platreef country rock is Archaean basement granite, partial melting of this protolith has resulted in the formation of a metamorphic rock referred to as a Granofels. The Granofels is present in a prominent interaction zone developed between the base of the Platreef and the underlying basement granite. As a result, the Mineralised horizon defined for the Platreef orebody often incorporates significant portions of the immediate footwall.

The Platreef strikes north north-west/south south-east across the length of the Mogalakwena Mineral Right area, dipping at an average angle of 40° to 50° to the west with local flattening occurring. Within the mining complex, the Platreef is structurally affected by dolerite dykes ranging between 5m and 40m in width and several predominantly lateral fault systems such as the Drenthe, Mohlosane, NM and Pit fault systems, orientated in a north-east/south-west direction, dipping between 60° and 85° towards the south-east.

The fault systems display normal to reverse fault displacements ranging between 50m and 600m, with the up-thrown blocks proving favourable to mine design. The dykes and Platreef adjacent to major fault systems constitute areas of no mineralisation and are discounted as geological loss zones. The Platreef hosts significant dolomite inclusions in the southern region of the mining area and these also constitute geological loss zones.

Mining Methods

• Truck & Shovel / Loader

Summary:

The mining of the orebody is by open-pit methods whereby material is extracted in vertical benches to create a large open excavation. Benches are mined from top to bottom and are accessed by means of haul roads in the hanging and footwall to connect multiple benches to surface entry and exit points. Open-pit mining is a widely used surface-mining method to extract minerals relatively close to surface by means of drilling, blasting, loading-and-hauling operations. Material is moved by means of truck-and-shovel to the processing plants, stockpiles and wasterock dumps along a network of constructed surface roadways. The walls of the open-pit excavation are mined at the maximum allowable slope angle achievable within the specified geotechnical constraints, and berm-offsets are created between benches to reduce the potential risk of rock falls along the overall slope. The final shape of the excavation is determined by the overall economics of the extraction process and is generally subdivided into three-dimensional phases expanding the open-pit to maximise the potential net present value of the mine within specified constraints.

Mining areas comprise three open-pits: Zwartfontein South, Mogalakwena North and Central. Pit depths vary from 128m in South pit to 283m in North pit. Ore is milled on-mine at the North and South concentrators as well as at Baobab concentrator, which is located some 90km off-site.

Mining of the orebody is currently by open pit methods whereby material is extracted (drill, blast, load, and haul) in vertical benches to create a large open excavation. Benches are mined from top to bottom and are accessed by means of haul roads in the hanging and footwall to connect multiple benches to surface entry and exit points.

Material is moved by means of truck and shovel to the processing plants, stockpiles, and waste rock dumps along a network of constructed surface roadways. These haul roads are gravel and are sprayed with a commercial dust suppressant according to a detailed schedule.

The walls of an open pit excavation are mined at the maximum allowable slope angle achievable within the specified geotechnical constraints, and berm-offsets are created between benches to reduce the potential risk of rock falls along the overall slope. The final shape of the excavation is determined by the overall economics of the exploitation process and is generally subdivided into three-dimensional phases expanding the open pit to maximise the potential net present value of the mine within specified constraints.

Waste rock from the open pit areas is placed in proximity to the open pit activities in dedicated Waste Rock Disposal Facilities. With the exception of Zwartfontein and Sandsloot Pits (which will be utilised for anthropogenic aquifer development), the open pits at MM Complex will remain at closure as final voids.

Mogalakwena Mine intends to exploit the Sandsloot (Zone 1) resources deeper than the current open pit horizons by changing the current mining method from an open pit mining process to an underground mining process (first phase). Studies are currently being undertaken to confirm the optimal development of the underground mine. MM anticipates that the proposed underground operations could extend the life of the mine with ~49 years and will similarly be influenced by market conditions, production rates and future underground mining scenarios.

Simultaneous to the development of the underground, the open pit mining will continue allowing for the final open cuts to continue until optimised shell extent has been reached. South Pit will be extended to bridge South Pit and Central Pit for the further development of the super pit. Pit access ramps for the super pit will be maintained to the eastern footwall wall to provide the shortest possible haul route to the WRD’s, strategic stockpiles and the primary crushing plant. To allow for final open cut / optimised shell extent, one last pushback/cut is planned for the Zwartfontein Pit.

In support of continual combination mining, waste rock material will need to be disposed of on surface. The North Waste Rock Disposal area will be extended in footprint area as well as height and the RS3, and W020 Waste Rock Disposal Area will be extended in footprint and height to accommodate the additional material removed from both the open pit and underground operations. Waste rock will also be utilised to construct anthropogenic aquifers within the Sandsloot and Zwartfontein open pit areas to support future mining operations with water security aspects.

In July 2022, at the Mogalakwena PGMs operation, Anglo American launched the prototype for a fleet of hydrogen powered mine haul trucks – a world first at this scale.

Comminution

Crushers and Mills

Summary:

• Ore is transported by haul trucks to the gyratory crusher and by means of conveyors to the mineral processing plant, as well as within the plant;
• Crushing is achieved in three phases using a gyratory crusher as a primary crusher in an open circuit, followed by secondary and tertiary crushing with associated screening;
• Conveyor feeds the primary mills from the crushed ore stockpiles;
• Following exposure of the PGM and base metal surfaces in the milling circuit, reagents are added to the milled product streams to prepare the minerals for flotation.

The concentrator is constrained by the A & B Section primary autogenous mills since the very hard Platreef ore is not amenable to autogenous milling circuits. This is exacerbated by the low aspect ratio of the existing mills. The A & B-Section primary mill constraint is to be removed by the following plant modifications:
• Installation of a new crushing and screening circuit after existing primary gyratory crusher comprising secondary cone crusher (closed with a screen) followed by HPGR;
• Splitting the existing fine ore stockpile (FoS) withdrawal conveyor into two separate conveyors that will reclaim fine ore to the existing fine ore silo via the existing portion of the modified conveyor (to feed the in-circuit crushing section) and reclaim fine ore to the new crushing and screening circuit (supplementary feed) via a second withdrawal conveyor operating in the opposite direction;
• Converting the A & B-Section primary autogenous mills to ball mills. A second drive will be added to each of the ball mills to increase the installed power per mill, which will enable maximum power draw to be attained;
• The existing in-circuit crushing (ICC) section that was previously used to crush pebbles from the autogenous mills will be retained to prepare the mill feed to the C-Section primary ball mill. Grizzly undersize material will be transferred to the ICC section via the existing fine ore silo and conveyors systems;
• Upgrade of the existing final concentrate thickener drive and rake system and installation of a froth skimmer;
• Installation of an additional final tails thickener; and
• Upgrade of several slurry pumping systems within the plant.

2011 - Regrind mills:
Mogalakwena South Concentrator - 3 x IsaMill™M10000;
Mogalakwena North Concentrator - 5 x IsaMill™M10000.

Processing

• Purification & crystallization
• Acid plant
• Smelting
• Ore sorter (multi-sensor)
• Electric furnace
• Hydrochloric acid (reagent)
• Crush & Screen plant
• Flotation
• High Pressure Acid Leach (HPAL)
• Magnetic separation
• Dewatering
• Solvent Extraction & Electrowinning
• Dissolving & Crystallising

Summary:

There are two mineral processing plants at the mine, Mogalakwena North Concentrator (MNC) and Mogalakwena South Concentrator (MSC).

The mine is currently processing, on average 13 Mtpa (based on 2018 and 2019 figures) through the existing North and South concentrators. The South Concentrator (MSC), with a current milling capacity of 4.2 Mtpa, may be considered for decommissioning once the Third Concentrator (M3C)12 is commissioned in 2030. With the M3C, Mogalakwena Complex will reach a milling capacity of 21.3 Mtpa. Approval for the construction of the M3C was granted in 2021. The M3C will have a milling capacity of 12 Mtpa whilst the North Concentrator will be maintained at 9.3 Mtpa.

Study work on the Mogalakwena third concentrator and associated debottlenecking of downstream processing capacity has been completed. The project should be value-accretive but further work is being postponed while study work on the underground development is prioritised.

Some ore is also processed at the Sibanye-Stillwater Baobab Concentrator which is located approximately 90km offsite. The Platinum Group Metals (PGMs) are extracted from the ore in the form of a concentrate that is transported to the AAP Polokwane Smelter for smelting to produce furnace matte. The matte then undergoes an acid-converting process at the Waterval Smelter Complex in Rustenburg, where after it is initially refined at the Base Metals Refinery (BMR) and refined to the final product at the Precious Metals Refinery (PMR).

Flotation
The separation of the valuable content from the ore takes place in flotation cells where reagents are added to an aerated slurry to produce high-grade PGM-bearing concentrate.

Smelting
Use of electric furnaces to smelt concentrate to produce a sulfur-rich matte with gangue impurities removed as slag.

Slag Cleaning
Converter slag is reduced in an electric furnace to recover PGMs and base metals for recycling back to the converter.

Converting
Oxygen-enriched air is blown through a top submerged lance converter to oxidise sulfur and iron contained in furnace matte to SO2 gas and slag respectively. The resulting converter matte is slow-cooled to concentrate PGMs into a metallic fraction.

Magnetic Concentration Plant (MCP).
Crushed converter matte is milled and the PGM fraction is separated magnetically. This is pressure leached to yield a solid final concentrate that is sent to PMR. Base metal-rich non-magnetic solids and leach solution are processed further in the base metal refinery.

Acid Plant
The SO2 gas is converted to SO3 by passing it over catalytic beds and the subsequent addition of water produces 98% sulfuric acid which is sold to fertiliser manufacturers.

Leaching
Base metal-rich solids are leached in high-pressure autoclaves and contacted with MCP leach solution to yield separate nickel and copper streams.

Purification
The separate nickel and copper streams are purified. During this process cobalt sulfate is recovered.

Electro-Winning
Nickel and copper metal cathodes are produced by passing electrical current through the separate purified stream.

Crystallisation
Excess sulfur in solution is neutralised with sodium hydroxide and crystallised to form a sodium sulfate product.

PGM Refining
Final concentrate is dissolved using hydrochloric acid and chlorine gas. PGMs are sequentially separated and purified to yield platinum, palladium, iridium, rhodium, ruthenium and gold. Osmium is precipitated as a salt.

2021 - A full-scale ore sorting (BOS) unit, which will deliver improved grade feed to plants through the early rejection of waste, reducing energy consumption, water usage, and unit costs in the process, is now operational at our PGMs business’s Mogalakwena North Concentrator. A modular ultra-fines recovery plant has also been constructed there, which will address the industry-wide challenge of reducing ultra-fine mineral losses, with the potential to increase recovery rates by up to 3%.

2022 - A full-scale coarse particle recovery (CPR) plant has been constructed at the Mogalakwena North concentrator, with start-up anticipated in late 2023.

2023 - The bulk ore sorting (BOS) technology was unsuccessful and the roll-out of this technology paused. In addition, the anticipated output from the coarse particle recovery (CPR) technology of ~18koz of PGMs has not materialised requiring further test work to be completed during the first half of 2024.

Hydraulic Dewatered Stacking (HDS)
During June 2023, Anglo American initiated a second trial at Mogalakwena platinum mine in South Africa, targeting the application of HDS into an existing facility.

Bulk Ore Sorting
Anglo American is optimising mining processes through technologies that target the required metals and minerals more precisely, with reduced water, energy and capital intensity, and producing less waste. These technologies include bulk ore sorting (BOS), coarse particle recovery (CPR), fines flotation, dry processing and novel classification, with their implementation integrated into resource development planning.

A full-scale BOS unit is operational at our PGMs’ Mogalakwena North concentrator (c.70% of complex feed). The unit is configured to reject waste prior to entering the concentrator, increasing plant feed grade.

A modular ultrafines recovery plant was installed at Mogalakwena to address the industry-wide challenge of reducing ultrafine mineral losses. Results of the trial indicate that the use of ultrafines recovery technology significantly increases product grades at equivalent metal recoveries. In 2024, ultrafine recovery modules will be implemented at Mogalakwena.

The project allows for ease of transportation and lowers energy footprint, with 30% less mass transported to high intensity downstream smelters. The sensor fusion loop in South Africa has been used to support BOS operations globally, enabling the development of intellectual property on selective mining and ore sorting.

Pipelines and Water Supply

Summary:

Potable Water Supply
Potable water is obtained from the Commandodrift (currently not in use), Potgietersrust Platinum Limited (PPL) (1.95 ML/d) and Blinkwater (0.8 ML/d) wellfields, totalling a permissible abstraction volume of 2.75 ML/d. The abstraction of groundwater at these wellfields has been authorised by the Department of Water and Sanitation (DWS) under Mogalakwena Complex’s Water Use Licence (WUL) (reference number 27059655).

Additional boreholes situated on the mine site have been authorised for abstraction and potable water use under the new WUL (No. 14/A61G/GICABJ/5053). These boreholes are in addition to the wellfield boreholes that are authorised under the original WUL.

Majority of the wellfield water is used for domestic purposes and only a small percentage is used in the process at Mogalakwena South Concentrator as a back-up supply.

Potable water treatment is limited to softening into two softeners each with a capacity of 70 m3 /hr to a maximum of 80 m3 /hr. Softening involves the addition of sodium chloride and subsequent ion exchange. The water softening tanks are located within the plant area.

The current concentrators are the net consumers of water i.e., requires fresh water source as top-up water due to the requirement for high quality water for reagent make-up, have inherent losses across the Tailings Storage Facilities (TSFs) resulting mainly from evaporation and interstitial lock-up, evaporation from the concentrator unit processes (mills, floatation cells, thickeners etc), and the requirement for potable water for human consumption and ablutions.

The Third Concentrator (M3C) (not yet constructed) has been designed to receive 100% of the recovered water from the TSFs in an effort to reduce the consumption of imported potable water as far as possible.

Numerous potable water pipelines are located within the mine complex for the distribution of potable water to the various operational areas.

The proposed Hydrogen Production Facility (located on Portion 14 of Erf No. 823 Armoede) will require a net water consumption of approximately 16 m3 /hour to feed the electrolysis system.

To achieve hydrogen production plant daily production of approximately 35t per day, 36m3 /h of effluent water will be fed to the water treatment plant (via a 3,61km192 new dirty water pipeline) located at the hydrogen production plant. The water treatment plant has a recovery rate of 44% based on the effluent water quality, of which 16m3 /hr (high quality de-mineralised water for the electrolysis) will be fed to the electrolysis system, while the reject water at 20m3 /h will be pumped via a new 0,73km dirty water pipeline to Vaalkop v-drain. The reject water in the v-drain will gravitate to the existing return water dam located north-west of the Vaalkop Tailings Storage Facility.

Process Water
The consumption of process water (in order of highest to lowest) is summarised as follows:
• Mill circuit dilution water;
• General dilution water across the concentrator;
• Spray water from screens and flotation cell launders;
• Flushing and hosing water; and
• General sump top-up water.

Process water is obtained from:
• Treated sewage effluent (TSE) from the Mogalakwena North and South Concentrator Waste Water Treatment Works (WWTWs) and the contractors camp WWTW;

• Off-site Infrastructure - Mokopane (up to 6 Ml/d is authorized) and Polokwane (up to 20 Ml/d is authorized) municipal Treated Sewage Effluent (TSE).
o Mokopane Waste Water Treatment Works WUL Number 16/2/7/A600/D3/X/1 dated 25 April 2003 issued to Mogalakwena Municipality allowing for the provision of the Treated Sewage Effluent to Mogalakwena Mine.
o The TSE is pumped to Dam 1160, via a pipeline system

• Fissure water and rainwater collected from active pit dewatering authorised through the current WUL;
o A pipeline system has been constructed to transfer excess water from the pits to Dam 1160 and the Tailings Storage Facilities Return Water Dams and RWD extension.

• Return water from the TSFs which are collected within the Return Water Dams (RWD’s);
o The return water from the TSF’s is returned to the concentrator for use as top-up water.
o The quality of the return water from the Blinkwater and Vaalkop TSF’s in terms of water chemistry and suspended solids renders the water adequate for most services that are supplied the process water inventory at the concentrator.

Contaminated stormwater runoff collected from various on-mine areas in dirty water containment facilities i.e., stormwater dams and sumps.

Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Concentrator Manager	Herman Kemp		Mar 14, 2024
General Manager Sustainability	Sam Kgarimetsa		Mar 14, 2024
Mining Manager	Mothibe Jerry		Mar 14, 2024
Production Manager	Judd Barlow		Mar 14, 2024
Sr. General Manager	Willie Noordman		Mar 14, 2024
Sr. Mine Planner	Witness Netshikulwe		Mar 14, 2024