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By K. M. Uderstadt, G. C. Howell, L. de Villiers

This paper highlights the advantages of developing tailings storage facility-specific water balances. A case study illustrates how such focused analysis provides clearer insights into water storage and release, supporting improved conservation, regulatory compliance, and enhanced stability of tailings storage facilities. A robust water balance informed by up-to-date hydraulic data is essential for long term management. It is proposed that tailings storage facility-specific water balances should be regarded as standard practice in mining.

Apr 8, 2026

By N. C. Steenkamp

Clay minerals are present in ores and their colloidal behaviour in slurries impacts on the full metallurgical process from comminution to the tailings storage facility. Geotechnical classification of tailings has been based on parameters such as grain size. This paper proposes that this parameter does not consider rheology and plasticity, and, while. Atterberg limits are useful, they do not consider other aspects such as active clay and chemical porewater.

Apr 8, 2026

By J. Raath, A. J. Fischmann, C. Spagnuol, E. D. Brooks

This paper demonstrates the use of Clean TeQ Water’s ATA® rapid dewatering technology as an alternative approach to the tailings paddock buttressing method which is currently being implemented. ATA® is a three-component system where the tailings stream is separated into fines and coarse fractions utilising a hydro-cyclone. The results from the pilot demonstrated that the use of ATA® offers significant advantages, including higher homogeneity in the buttress, higher permeability, and faster settling rates.

Apr 8, 2026

By Stephen Benyo

The future of mining will not be defined by how deep operators dig, but by how intelligently they separate. As ore grades decline, environmental concerns intensify and water remains a global crisis, the industry is discovering that its greatest opportunities for progress lie not at the pit or face, but downstream — within the separation processes that govern water, tailings and byproduct streams. In this context, clarity has become a defining principle — both literally and metaphorically. Clear process water enables reuse and regulatory compliance. Clear separation of solids and liquids recovers valuable resources, supports safer operations, lowers energy demand and provides stable tailings management. Clear visibility into how these systems perform allows mine operators to make better decisions, reduce operational risk and unlock value that is often hidden in overlooked waste streams.

Apr 1, 2026

By Ronald D. Jacksha, Jason B. Coder

Wireless technologies are becoming vitally important for modern mining operations. Used for increasingly complex tasks — such as miner and asset tracking, proximity detection, teleremote and autonomous equipment operation, and environmental monitoring — the ability of wireless systems to perform their intended functions satisfactorily in the presence of other wireless systems (coexist) is critical not only to the successful operation of modern mines but also to the safety and health of mine workers. Concerns regarding the ability of wireless systems to coexist can often hinder the decisionmaking process for adopting technologically advanced wireless systems. However, with adequate knowledge of the concepts of coexistence and appropriate wireless system management, coexistence concerns do not need to be an impediment to the successful adoption of wireless systems. There are several common wireless coexistence-related fears that can inhibit adoption of wireless technology: fears that safety-related systems may not operate properly when needed, failures could disrupt production, and wireless systems may inherently require costly troubleshooting. Most of these fears can be alleviated through proactive activities.

Apr 1, 2026

By P. O. Osifo, K. Premlall, X. Goso, R. H. Matjie, M. R. Mulaudzi, J. R. Bunt, K. Mphahlele

This study investigates the transformation of pyrolytic spent tyre-derived char and crumb rubber into high-performance activated carbon chars for industrial wastewater remediation. Utilising an in-house macro-thermogravimetric analysis system under an argon atmosphere, spent tyre-derived activated carbon char were synthesised via physical temperature activation and aqua regia demineralisation. Comprehensive characterisation using x-ray diffraction, Raman spectroscopy, and scanning electron microscopy, revealed a predominantly amorphous structure with nanoscale crystallites (~1 nm) and active surface functional groups. Proximate analysis confirmed that both crumb rubber and leached tyre crumb rubber with aqua regia derivatives achieved favourable compositions (ash ≈ 9.6%; fixed carbon ≈ 84%), comparable to commercial activated carbon (AC). At an optimal activation temperature of 850°C, the char of tyre crumb leached with aqua regia variant exhibited a significant surface area of 300 m²/g. Crucially, the tyre crumb char produced at 850°C variant developed a pore volume of 0.8 cm³/g—effectively doubling that of commercial activated carbon (0.4 cm³/g)—facilitating the sequestration of large organic molecules. In application tests using high-strength starch wastewater, char of tyre crumb leached with aqua regia and tyre crumb char, both produced at 850°C, achieved total organic carbon removal efficiencies of 60% and 50%, respectively, bridging the performance gap between waste-derived and commercial adsorbents. These findings validate waste tyres as a viable, low-cost precursor for industrial-grade adsorbents, offering a sustainable circular economy route for tyre valorisation and reduced industrial disposal costs. Future research will focus on kinetic modelling and the recovery of zinc from spent tyre-derived activated carbon char residues.

Mar 30, 2026

By R. C. A. Minnitt, A. Akpabio

This study presents a rigorous comparison between ordinary kriging and commonly used machine learning algorithms, those being, linear regression, support vector regression, decision trees, random forests (RF), and k-nearest neighbours for spatial interpolation of platinum grade estimates in a complex ore body within the Bushveld Igneous Complex. Using only X and Y coordinates as predictors, both ordinary kriging and machine learning models were evaluated at point and block supports under traditional and spatial block cross validation frameworks. While naive validation results suggested superior performance for k-nearest neighbour and random forest (R² = 0.92 and 0.86, respectively), these were revealed to be overly optimistic under spatial dependence. Spatial block cross validation results demonstrated substantial declines in model performance, with R² often falling below zero, particularly for decision trees and k-nearest neighbour, indicating strong overfitting and limited generalisability. Ordinary kriging exhibited more stable, albeit modest, performance under spatial validation, reflecting its strength in geostatistical interpolation when contextual geological variables are unavailable. The study underscores the critical importance of spatially aware validation in resource estimation and highlights that machine learning models constrained to spatial coordinates behave as interpolators rather than true learners of geological variability. Recommendations are provided for future work incorporating geological information to enhance predictive robustness.

Mar 30, 2026

By M. -B. Kime

This study applies attainable region analysis to optimise cobalt recovery from oxidised ores via reductive leaching with sulphur dioxide and sulphuric acid. The attainable region framework enables systematic visualisation of trade-offs between cobalt yield and sulphur dioxide loss, guiding reactor network design beyond conventional mass balance modelling. Experimental column leaching trials, supported by validation runs, were conducted under controlled flow and reagent conditions. Kinetic parameters for cobalt dissolution and sulphur dioxide consumption were used to simulate reactor trajectories and construct attainable region envelopes. To ensure hydrodynamic realism, residence time distribution tests confirmed partial plug flow behaviour with dispersion effects, justifying the use of hybrid reactor models in the attainable region simulations. The results revealed that increasing recirculation ratios improves cobalt yield while reducing sulphur dioxide losses, with attainable efficiencies exceeding 90% cobalt recovery and < 20% sulphur dioxide loss. Importantly, the study proposes practical reactor network configurations for future implementation, including staged percolation columns with intermediate mixing zones, oscillatory flow reactors, and modular fluidised bed systems. These designs offer scalable pathways to translate attainable region-based optimisations into industrial practice. Compared to traditional modelling, attainable region analysis provides a geometric decision support tool that captures multi-objective trade-offs and reactor interactions, offering novel insights for continuous leaching system design. This work advances the application of attainable region methodology in minerals engineering by bridging theoretical optimisation with practical reactor design, supporting sustainable cobalt recovery from both primary ores and recycled feedstocks.

Mar 30, 2026

By C. Musingwini, G. Njowa, M. Burnett, C. C. Birch

From 2022 to 2040, the global demand for mineral commodities is projected to increase by fourfold to six-fold, largely due to traditional drivers such as population growth and urbanisation compounded by the adoption of decarbonisation technologies that are more mineral intensive than fossil fuel technologies. To meet this projected demand, companies operating in the minerals industry should accelerate the development of mineral projects. Since most of the companies generally operate in multiple geographical, regulatory or legislative jurisdictions, it is critical that the information on Mineral Resources and Mineral Reserves they report on in the public domain should be comparable and consistent across different jurisdictions. The Committee for Mineral Reserves International Reporting Standards fosters alignment of national and regional mineral reporting codes through an internationally accepted template that creates common technical understanding of definitions, classification, estimation processes and the Public Reporting of Exploration Results, Mineral Resources, and Mineral Reserves. The Committee for Mineral Reserves International Reporting Standards Template-based codes guide reporting at respective national and regional levels. Since mine planning is critical in the conversion of mineral resources to mineral reserves, a shared technical understanding should aid comparability of mine planning results. However, differences persist in the way mine planning results are reported. Unlike most previous studies, which have primarily focused on comparing mineral reporting codes, this paper updates and extends such comparisons by exploring how similarities or differences in reporting should influence the mine planning process. It also recommends some principle and process changes to assist mine planning professionals to improve consistency and comparability in reporting mine planning results.

Mar 30, 2026

By C. Aldı, O. Yaral

For the more economical excavation of tunnels in underground mining activities, the selection of mechanised excavation machines (such as roadheaders, electro-hydraulic drills, etc.) and the analysis of performance prediction that can be used in estimating machine energy consumption have been subjects of research from past to present. One of the parameters to be considered in studies examining these methods, is the grinding process. The success of increasing efficiency in grinding is expressed by a reduction in energy consumption. The goal of a grinding process is to maximise the grinding amount at the appropriate grinding size while minimising the energy consumption per tonne of the fragmented material. Today, the depletion of high-grade ore deposits has largely directed the mining industry towards low-grade but large reserve ore deposits. This shift has particularly increased the importance of the grinding process, as it is dependent on particle liberation. Grinding is a critical step in reducing the mineral to the appropriate size, and energy consumption poses a significant challenge in this process. As a result, researchers have conducted various studies focusing on energy efficiency and cost optimisation in this field. In this study, the grindability of 7 different coal environment rocks (sandstone, siltstone) from the Zonguldak Basin, Uzulmez Region was investigated. For this, Hardgrove Grindability Index and Bond Work Index tests were conducted. While determining the relationships between grindability and other parameters, the results obtained from the Hardgrove Grindability Index (HGI) test were used. The energy values found in the Bond Work Index (BWI) test were used to evaluate the excavatability of the rocks. Additionally, tests for strength, hardness, drillability, and abrasiveness were conducted to observe the impact of other parameters on grindability. Considering the results obtained from the experiments, significant relationships were found between the grindability of the rocks and other parameters.

Mar 30, 2026

By K. L. Morton

This technical note reviews the status quo of mud rushes and flooding, which have claimed them lives of many people in underground mines in South Africa and globally. Given that the causes are well known and can be managed, the note calls for the development of a national and global standard on flood and mud rush prevention in order to save lives.

Mar 30, 2026

By J. Petersen, K. Shaik1, H. Kolev, Z. Cherkezova-Zheleva

Sperrylite is one of the most abundant platinum minerals globally, valued for its economic importance but also known for its highly refractory nature, making it difficult to process via the conventional route. This study explores the oxidative leaching of sperrylite using a cyanide–ferricyanide system, with a key focus on characterisation of the mineral and surface speciation under varied leaching conditions using x-ray photoelectron spectroscopy. The parameters investigated include the effect of sodium cyanide concentration, the use of potassium ferricyanide as an oxidant, copper sulphate pentahydrate as a catalyst, as well as the effects of temperature and particle size. A limited set of leaching tests was carried out to study the surface chemistry rather than optimising dissolution conditions. This approach identified mineral oxidation states and shifts in binding energies, prior to and post leaching. XPS analysis of sperrylite’s surface chemistry identified key species, comprising the bulk Pt(II)–As (≈73 eV) and As(–I)–Pt (≈41.8 eV) states, together with surface oxidation products Pt(II)–O (≈72 eV), Pt(IV)–O (≈74.5 eV), As(III)–O (≈43 eV) and As(V)–O (44.5 eV). Leaching led to the removal of pre-existing oxides on the ultra-finely ground sample, exposing the underlying bulk species. In contrast, the crystalline sample with an initial low concentration of oxides, generated higher amounts of fully oxidised species after leaching, reflecting greater surface reactivity.

Mar 6, 2026

By J. Sehata, J. Tshilongo, I. Govender, S. Pikinini, T. L. Moodley, M. Raedani

In the face of dwindling Merensky ore reserves in the early 1990s, Mintek developed the MF2 flotation circuit to economically recover platinum group metals from the shallow upper group-2 chromitite reef. By aligning the primary and secondary grind to the platinum group metal liberation kinetics, excessive fine chromite generation was avoided, and thus one could consistently produce high-grade concentrates (>200 g/t platinum group metals) with low chrome content (<3% Cr2O₃), well within smelter tolerances. This, coupled with upper group- 2's low-cost open-pit mining, made it particularly attractive to investors and mining houses alike. As a result, deeper lying reefs like middle group and lower group with lower platinum group metals grades and complex mineralogy, were primarily mined only for chromite using density-based separation processes (like spirals), of which the waste tailings are best classified as secondary platinum group metals resources. Today, with global platinum group metal demand rising and high grade upper ground-2 reserves rapidly diminishing, the industry must revisit these middle group and lower group tailings. Mineralogical analysis reveals several challenges: Middle group tailings feature platinum group metals locked within silicate matrices, while lower group tailings contain fine chromitite fragments, and are hosted within non-floating laurite grains, each presenting liberation and gangue issues. Smelter constraints still demand concentrates below 3% Cr₂O₃, requiring solutions that consider both platinum group metals recovery and chrome entrainment. To develop a solution, two lower group chrome spiral tailings samples were obtained from a large chrome mine: Sample A (+425 μm – 106 μm) and Sample B (−106 μm). Initial assays showed Sample B contained higher platinum group metal grades but also higher Cr₂O₃. As such, different blends of flotation feeds were evaluated using ratios of 90:10 (C1) and 80:20 (C2) of Sample A to Sample B, targeting the coarse fraction's lower chrome content while recovering valuable platinum group metals from the fines. This work proposes a practical route for mining houses to unlock additional platinum group metal value from lower group ore spiral tailings. By optimising blending ratios and reagent suites, it is possible to meet smelter chrome and platinum group metal grade thresholds, whilst still obtaining economically viable PGM recoveries.

Mar 6, 2026

By B. McFadzean, N. Patterson, M. Becker, S. Geldenhuys

The retreatment of secondary tailings for platinum group metals recovery presents a range of potential challenges, which vary depending on the nature of the original ore and the type of pretreatment it was subjected to. These challenges include the prevalence of ultrafine particles, which promote slimes coatings on valuable minerals, hinder bubble-particle attachment, increase pulp viscosity, and lead to higher gangue entrainment; surface oxidation of minerals, which alters their floatability; and the presence of deleterious gangue minerals and residual platinum group metal species that are inherently difficult to recover by flotation. This study compares the batch flotation performance across a range of tailings samples from the eastern and western limbs of the Bushveld Complex. A complementary mineralogical analysis was conducted to gain deeper insights into mineral behaviour. The paper evaluates these findings to identify the key factors contributing to poor platinum group metal performance.

Mar 6, 2026

By R. Letsaole, H. Mabowa, J. Sehat, J. Tshilongo, T. Rampfumedzi, N. Ntsasa, A. Mkhohlakal1

This study explores the use of co-collectors to enhance the recovery and determination of rhodium during fire assay with lead collection, followed by acid dissolution using conventional hot plate methods. Rhodium, a critical platinum group metal, poses analytical challenges due to its low natural abundance and complex chemistry. Among the co-collectors tested, palladium and tellurium demonstrated significantly improved rhodium recoveries, ranging between 100% and 120%, whereas silver resulted in poor recovery and higher error margins. These findings highlight that co-collectors can enhance the efficiency and sensitivity of platinum group metal analysis, although their effectiveness is dependent on the chemical interaction with the target element. Acid dissolution was essential to ensure complete digestion of prills prior to analysis, enabling accurate quantification of rhodium. Overall, the findings suggest that palladium and tellurium are effective co-collectors for rhodium determination in fire assay, while silver and lead flux alone are unsuitable. This work provides important insight into optimising fire assay procedures for reliable rhodium analysis, with potential benefits for platinum group metals recovery and economic evaluation.

Mar 6, 2026

By C. M. van der Walt, J. F. van Rensburg, H. J. Groenewald

The South African platinum group metals mining industry faces considerable operational costs, with compressed air networks’ annual costs accounting for up to 35% of total electricity consumption. Amidst escalating electricity tariffs and volatile commodity prices, enhancing energy efficiency has become critical for economic sustainability. This study addresses the prevalent issues of mismanagement and inefficient use of compressed air on the demand side, such as leakages and unauthorised use for ventilation. While previous research has identified these inefficiencies, a gap exists in the continual monitoring and reporting of network performance to drive sustained improvements. This paper presents a practical solution developed and applied within a major South African platinum group metals mining group. The methodology focuses on a continual monitoring and reporting framework to improve demand-side management. The implementation of this solution has demonstrated significant financial and energy-saving potential. Key findings from case studies include: 1) the mitigation of R150,000 in costs over five days by rectifying a single instrumentation fault, 2) a potential annual energy saving of up to 5.6 GWh (R10.6 million) by enforcing valve closures during non-productive periods, and 3) an annual reduction of 3.7 GWh (R7.2 million) through improved underground ventilation controls. These outcomes underscore the value of a systematic, data-driven approach to managing compressed air consumption, offering a viable strategy for cost reduction and enhanced efficiency across the platinum group metals industry.

Mar 6, 2026

By Y. Zhan1, T. Moodley, M. A. H. Zahid

Mining operations are under growing pressure to improve safety and efficiency while dealing with aging infrastructure, complex processes, and workforce constraints. Although many sites are equipped with surveillance cameras and control systems, critical events often go unmonitored or under-analysed due to the lack of intelligent interpretation tools. Cameras typically act as passive recorders, requiring manual review by control room operators; a process that is labour-intensive, error-prone, and reactive. Vision AI is emerging as a transformative solution, combining computer vision and artificial intelligence to deliver real-time, actionable insights. This technology has evolved along two key phases: traditional object detection, and more recently, multimodal large language model integration. This paper presents solution architectures, deployment results, and key insights from real-world implementations across underground operations, open-pit truck-shovel operations, and smelter operations, demonstrating how Vision AI is reshaping mining operations to become safer, more efficient, and more intelligent.

Mar 6, 2026

By B. S. Xakalashe, I. J. Geldenhuys, M. W. Erwee, Q. G. Reynolds, R. T. Jones, S. P. Tsebe

Aspects of the production of platinum group metals by reductive smelting in direct-current arc furnace processes are investigated using a computational modelling approach. The replacement of fossil carbon as a reductant by alternative reductants such as silicon carbide, ferrosilicon, and hydrogen is desirable for reducing direct greenhouse gas emissions from such processes, but the impact of these changes on the electrical operability of the process is poorly understood. This paper presents a study of plasma arc behaviour in the context of the ConRoast® reductive smelting process for Upper Group 2 ore as well as processes for recycling of automotive catalysts, using an integrated computational modelling workflow. It was found that the freeboard gas compositions, plasma properties, and arc behaviour were all affected by the choice of reductant, particularly in carbon-free smelting using ferrosilicon or hydrogen.

Mar 6, 2026

By Robert McIvor

The following is a summary of the Robert H. Richards Lecture on “Learning and Good Fortune on the Road to Discovery” presented at the Mineral & Metallurgical Processing Division (MPD) Awards Plenary Session on Feb. 23, 2026 during the MINEXCHANGE 2026 SME Annual Conference & Expo in Salt Lake City, UT.

Mar 1, 2026

By D. Morgan Warren, David Hanson, Alice Alex, Tom Meuzelaar, Heather Lawson, Sam J. S. Wright

Dynamic coal failure events remain a safety concern in underground coal mining due to their sudden nature and high fatality rate. Previous research utilized Principal Component Analysis on field samples revealing strong empirical correlations between positive failure history and low sulfur content (S) and high volatile matter (VM). Further studies indicated that bumping coals tend to be less mature and less well-cleated than non-failure coals. However, these in situ studies faced the challenge of distinguishing intrinsic coal properties from external geological and stress-related influences. This study augments previous findings through laboratory experimental testing of coal samples that included unconfined compressive strength, chemical composition analysis, and qualitative observations on cleating, combined with compositional data analysis and machine learning techniques, to isolate and understand coal’s inherent bursting capacity. These results further confirmed the relationship between coal chemistry and failure classification.

Feb 22, 2026