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By M Steinberg, M Amarant

Upstream Classifier are well-known in the iron ore industry for at least 15 years. At present, more than 60 units are in operation in Western Australia. The advantage of this technology is their capability to produce three products with one equipment – iron ore concentrate, iron ore middlings for further processing and slimes (tailings). The principal of this beneficiation process – upstream classification and upstream separation – will always remain. However, the optimisation of the classification and separation efficiency of the equipment itself is a continuous process driven by enhanced automation and instrumentation, design changes and the use of upstream and downstream information and requirements. Besides efficiency, the safety, maintenance and replacement conditions are very important subjects for the operation of an iron ore mine. The aim of this paper is to present a new allflux® upstream classifier design, which has been developed together with several iron ore producer from Western Australia. The new design benefits from its sustainability approach by dividing the entire equipment into small reusable parts. As a result, maintenance is minor, replacement much faster, lifetime much longer and costs much lower. Furthermore, it demonstrates new features to prevent hazardous working conditions such as confined space as well as new fixing devices to speed up the replacement of certain items and parts.

Sep 18, 2023

By M McCurd, M Lynch, B H. Yin, S Mendoza, C W. Bumby, Y Iwasaki, B Rumsey

Iron and steel production is responsible for approximately 6.3 per cent of global anthropogenic CO2 emissions. Direct reduction of iron with hydrogen is a potential route for decarbonising the iron and steel industry. Extensive small-scale laboratory experiments have been performed to test the feasibility of hydrogen-direct reduction of iron ores sourced from diverse geographical locations. However, test results from the batch reduction of small-sample do not necessarily translate to continuous commercial-scale processes. Establishing a small-scale continuous test reactor for H2- DRI process is challenging, requiring substantial resources and investment. The limited availability of small-scale reactors that enable testing under relevant conditions has become a major obstacle for H2-DRI development, leaving a big gap between laboratory success and proof of commercial feasibility. Here, we report on the recent commissioning of a continuous counter-flow vertical shaft reactor, which has a processing capacity of 6 kg/hr iron ore pellets at up to 100 NL/min H2 flow. We believe this to currently be the largest H2-DRI facility in the Southern Hemisphere. In this talk, we will discuss the design and construction journey for this reactor, starting from the initial system design to the initial demonstration of H2 reduction of titanomagnetite ironsand pellets. This reactor now enables a range of research capacities, including the validation of laboratory results on a larger scale with practical operational variables, feasibility assessment of hydrogen direct reduction of different iron ores on a commercial scale; identification of scalability, sticking, and other potential issues before building a full-scale plant; and a viable solution for producing small-quantity DRIs for downstream melting investigations. Overall, this new research facility offers significant benefits for assisting the transformation of iron and steel production to a more sustainable and green industry.

Sep 18, 2023

By M Camarda, A Pirson, F Vasconcelos, J Mesquita

ArcelorMittal Prijedor is a goethitic iron ore mine located in the north-west of Bosnia and Herzegovina, which mainly supplies ArcelorMittal’s European subsidiaries. Annual production of the asset stands at the level of 1.5–2.1 million tons of iron ore product which is sent to ArcelorMittal Zenica steelmaking plant. Two types of products with approximately 50 per cent Fe are generated in Prijedor through a process composed by crushing, screening, and magnetic separation stages. Within this process one of the tailings produced is called ‘ultrafines’. The ‘ultrafines’ product corresponds to the desliming hydrocyclones overflow in Prijedor plant, which is classified in a size fraction below 25 μm and corresponds to about 5 per cent of feed. This material is richer in iron than the coarser size fractions of the ore but do not present a good performance in concentration processes. In this way, several studies have been carried out during the last years to find solutions to use the ‘ultrafines’ material without success. In this context, the possibility of dehydroxylate the goethite contained in the material transforming the mineral into hematite and thus increasing the iron grade of the final product was investigated. During the research, several dehydroxylation tests with different temperatures and time of exposure were performed. Using dihydroxylation process at temperatures higher than 800°C it was possible to produce a material with 43 per cent Fe from the original 39 per cent Fe ‘ultrafines’ sample. In addition, the dehydroxylation tests confirmed that goethite becomes completely transformed into hematite at 400°C (with an exposure time of 60 mins) and material is completely sintered at 1200°C. A simulation study based on dehydroxylation tests results showed that it would be possible to use a ‘ultrafines’ product with Fe grade higher than 45 per cent to produce a material with 50 per cent Fe through a complete dehydroxylation process.

Sep 18, 2023

By Q Zhou, J Pan, D Q. Zhu, C C. Yang

Oxidised pellets have become an indispensable high-quality charge for blast furnaces (BF) due to their uniform particle size, high iron grade, high mechanical strength, good metallurgical performance, as well as relatively low energy consumption and gaseous pollutant emissions in pellet production. Nevertheless, due to the rapid development of the global steel industry, highquality pellet feeds are becoming more and more scarce. In order to broaden the source of pellet feeds and reduce the production cost of pellets, more and more steel mills are going to use coarse iron ore fines with relatively low iron grade and low impurities for preparation of desirable pellet feeds through a typical wet grinding-settling-filtering process. In this work, the grinding, settling and filtering behaviour of Brazilian and Australian iron ore fines are studied and compared, aiming at finding out the internal relationship between the mineralogical characteristics of different iron ore types and their grinding-settling-filtering performance. The results show that the grindability is heavily dependent on the hardness of iron ores, which is governed by the mineralogical characteristics of the raw materials. Usually the higher the hardness, the more grinding energy is required. Except for Brazilian specularite, Australian hematite-goethite type iron ore fines and Brazilian hematite ore fines exhibit good grindability with a Bond Work Index of about 10–15 kW•h/t. In addition, the settling and filtering performance of ground iron ores are largely affected by the density, mineralogical characteristics of iron ore fines (eg, quantity of clay minerals and goethite and porosity of ore particles), grinding fineness, etc. Generally, iron ore fines with higher density, lower quantity of soft minerals (clay and goethite) and larger particle size give superior settling and filtering performance. For iron ore fines with inferior grinding, settling and filtering performance, applying more energy-efficient grinding techniques, blending with ore types with good settling and filtering performance can reduce grinding energy consumption and improve settling and filtration rates to maximise the productivity of equipment and lower the operational cost

Sep 18, 2023

By Y M. Lee, Y Hong, B C. Kim

Since sintered ore is the primary source for producing molten iron in the blast furnace process, maintaining stable quality despite the utilisation of low-grade iron ore is crucial. However, conventional analysis methods, such as chemical composition, ore size distribution and types of iron ore, have limitations in developing the utilisation of new low-grade iron ore and predicting sintered ore properties. Sintered ores are formed through a complex melting process of granule particles consisting of iron ore, flux and fuel. Consequently, it has been investigated that analysis methods which apply the reactive properties of iron ore to predict sintered ore characteristics. In this study, we estimated the properties of iron ore by simulating the assimilation process of coarse ore, which influences the bonding strength of sintered ores and quantifying the degree of assimilation reaction. Pseudo particles were formed by granulating coarse ore (1–3 mm) with adhering fines, which act as primary melts and sintered at 1623 K. The bonding strength of individual sintered ores, formed from 11 different types of iron ore, was measured using a simplified Tumbler Index (TI) test and each value was indexed as the Iron ore Reactivity Index (IRI). By investigating the relationship between the degree of assimilation depending on iron ore properties and the characteristics of sintered ore, we demonstrated that sintered ores formed from more reactive iron ore exhibited stronger bonding strength. Moreover, when blending conditions resulted in a higher Iron Blending ore Reactivity Index (IBRI), the physical properties of sintered ore improved. The development of this analysis method is expected to not only enable careful consideration of iron ore usability but also allow for the advance prediction of sintered ore qualities by deriving the IBRI.

Sep 18, 2023

By M I. Pownceby, N A. S Webster, J R. Manuel, J M. F Clout, E Donskoi, N A. Ware

The relative influences of sinter mineralogy, sintering temperature, solid and pore macro- and microstructure on iron ore sinter physical strength are not yet fully understood. Whilst a range of analysis techniques have been used by researchers to evaluate sinter physical properties and sinter mineralogy, none have been able to directly link sinter mineralogy and physical strength under controlled conditions. CSIRO has developed a unique laboratory method to study the fundamental melting properties of fine iron ores in a laboratory furnace under a controlled temperature and gas atmosphere environment designed to simulate the industrial sintering process. Compacted tablet samples for a 0.41 per cent and a 2.5 per cent Al2O3 series were fired in a tube furnace at various temperatures, cooled, then tumbled using a modified Bond abrasion test apparatus to determine a relative tumble index (TI) at each temperature. Quantitative XRD (QXRD) analysis was then carried out on the tumbled samples and optical image analysis (OIA) was conducted on polished sections of a separately fired compact in each case. The amount of total SFCA was found to decrease with increasing firing temperature for both alumina series with the total amount of SFCA higher in the 2.5 per cent Al2O3 series compared to 0.41 per cent Al2O3 series samples. The increase in the amount of magnetite and hematite with increasing firing temperature was largely at the expense of a decrease in total SFCA. Overall, there was good agreement between the quantitative mineralogy determined from QXRD versus OIA for SFCA, hematite and magnetite. Qualitative analysis of high magnification images of the sinter correlated with both the OIA and QXRD results.

Sep 18, 2023

By W Malone, J Garrett

FLSmidth (FLS) has spent the last 15 years, working with customers and engineering houses to deliver innovative improvements in crusher safety, coupled with the latest, maintenance friendly, crusher design. The key focus being to prevent service personnel from working underneath the crusher during maintenance and obviate the need for personnel to be exposed to suspended loads when performing tasks such as, main shaft installation, for example. Improvements include: full top-service capability to ensure the safest and fastest way to disassemble the crusher for maintenance purposes, which also removes the requirement for a service cart; a selfaligning main shaft which ensures remote assembly is now possible, keeping service personnel well out of harm’s way; And rotable shells, or the ability to perform relines off-station, allows for quick shell ‘swap-over’ without the downtime associated with removing, refitting and curing time associated with epoxy backing. The high flow spider improves large material entry into the crusher, reducing blockages and downtime and therefore maintains crusher capacity. Each size of crusher in the range comes with an option to increase the standard feed opening to a larger one if desired to compensate for ‘blocky’ or ‘elongated’ feed material, a common problem for Pilbara hematite iron ores. Power capability has also been increased with a maximum of 1500 kW, to match the higher throughput capacities being achieved. This due to uprated eccentric speeds and larger discharge annulus. Increased eccentric throws and mantle diameters are also now a reality, when compared to more traditional designed gyratory crushers. To keep up with the improved design features of the Mk V, digitalisation has also been upgraded to maximise performance capabilities to ensure that the most efficient reduction and throughput capacities are achieved, whilst utilising the higher powers now available as standard. Condition monitoring ensures that the crusher is at its optimum operating capability by monitoring and adjusting the crusher settings via feedback from additional sensors, ie main shaft spin, temperature and vibration. Camera monitoring capabilities are available as is an advanced oil contamination monitoring system. As a result of the above design improvements, it will be shown that the Mk V range offers benefits such as: enhanced safety features, increased availability, faster maintenance turnarounds, higher power utilisation, equivalent product size at higher throughput capacities and with Remote operation capabilities. All of which result in a gyratory crusher with higher levels of safety and a lower per tonne operating cost.

Sep 18, 2023

By E Nunes, R Mendes, D Jacobson, G Cota, T Machado, E Santos, J Almeida, E Pereira9, B Raso

Grinding circuits are known to be the highest consumer of energy used in the ore comminution process, with high operational costs and sensitivity to ore conditions. The mining industry is being encouraged to look for more energy efficient processes while increasing the mass and metallurgical recovery; a specific example is projects with lower iron ore grades, which demands a higher level of liberation and resulting higher energy consumption. This has led to increased usage of high-pressure grinding roll (HPGR) technology as an alternative design within the comminution circuit. A growing use of the HRC™ HPGR technology has been used to generate concentrate through a more sustainable process. In the Brazilian state of Minas Gerais, the readaptation of iron ore beneficiation circuits has been initiated, replacing the traditional crushing-to-grinding flow sheet with circuits using crushing-to-HPGR flow sheets, with the main driver being reduced energy consumption. Utilising results from sampling campaigns and analysis of experimental data collected in an industrial plant, the work herein presents a case study from the JMN Mineração operating plant, where the HRC™ HPGR was used as an alternative to traditional grinding using horizontal mills. The results show that the HRC™ HPGR performance in this iron ore processing plant showed benefits in terms of reduced energy consumption as compared to the projected performance with a traditional grinding circuit.

Sep 18, 2023

By CIM Environmental, Social Responsibility Society

Within the mining industry, the pathway from exploration, to planning, construction, operation and closure has become more complex over the last few decades. The current financial, environmental and social influences present the mining industry with unprecedented challenges and opportunities. In addition, international environmental and social reporting standards and codes are becoming increasingly robust. The reporting requirements provide an added impetus for issuers to effectively manage environmental and social impacts and risks. Reporting requirements also provide the opportunity to be transparent. The intended audience for these Environmental, Social and Governance (ESG) Guidelines for Mineral Resource and Mineral Reserve Estimation includes practitioners, industry participants at all levels of skill and experience, corporate management and board members, government agencies, academic institutions and interested parties. For practitioners, this document provides underlying key principles of environmental, social and governance practices. The ESG Guidelines provide guidance for those using environmental, social, governmental and governance information when preparing and implementing mineral exploration programs and contributing to the preparation of mineral resource and mineral reserve estimates for mineral properties that are either at the study stage (i.e., scoping / preliminary economic assessment, pre-feasibility, or feasibility studies) or in operation. The guidelines can also be used to help mineral resource and mining companies apply good practice to manage their environmental and social risks and opportunities. Companies can identify and retain appropriate professionals to prepare environmental and social materials to support company studies. The guidelines are also a resource for companies developing effective environmental and social management strategies at any project stage. This document is not intended to be prescriptive and is not intended to provide exhaustive guidance on what to consider in terms of environmental, social, legal and governmental modifying factors in the preparation of MRMR estimates. Rather, it is intended as general guidance to assist companies and practitioners in considering and applying these modifying factors for MRMR estimates. This document is also not intended to guide environmental and social impact assessment (ESIA); however, the measures needed to manage impacts help inform the constraints and costs for defining mineral resources and mineral reserves and inform the costs and schedules of mineral project studies. All documentation of MRMR estimates made by an issuer and intended to be, or reasonably likely to be, made available to the public in a jurisdiction of Canada must comply with the requirements of National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101), as amended from time to time (Canadian Securities Administrators, 2016a and 2016b). Disclosure is not addressed in these ESG Guidelines. Determination of what to include in disclosures is defined in the applicable Securities’ legal frameworks. Appendix A presents a summary table showing the linkage of the principles and topics in these ESG Guidelines to the potential effects on project costs, schedules, government permits and approvals, social licence to operate and financing.

Sep 8, 2023

By I. Ince, S. Kahraman

Preparation of suitable core specimens for physico-mechanical testing s not always possible, particularly for soft and clay-bearing rocks. Although several indirect test methods have been proposed to predict the properties of rocks, specimen preparation from soft rocks for some indirect tests is still difficult. For such cases, the needle penetration test has been developed. In this paper we present a study on the predictability of the physico-mechanical properties of pyroclastic rocks from the needle penetration index (NPI). The NPI, uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), density, and porosity tests were performed in the laboratory on specimens from ten different locations in Turkey. Correlations were established between the NPI values and the physico-mechanical properties. Strong correlations were observed between NPI and both UCS and BTS. General correlations were found between NPI and both density and porosity.

Sep 6, 2023

By W. C. Joughin

The science of soil mechanics is 100 years old, and rock mechanics is about 80 years old. While methods of analysis and design have been developed and have evolved over time, these are relatively young sciences. The rapid increases in computing power and new technologies have enabled more sophisticated modelling and monitoring. However, there are still many aspects of soil and rock mechanics that are not well understood. Geotechnical failures, which have major consequences, still occur. These consequences may include environmental damage, major production holdups and associated loss of revenue, damage to infrastructure, and loss of life. High-consequence events, which are rare, are more difficult to anticipate and to design for, because by their nature they involve extraordinary circumstances or conditions, often geological in nature. The risks are usually mitigated by conservative designs and monitoring. Detailed geotechnical investigations help us to understand the natural variability of soil and rock masses and identify unusual or unexpected conditions. Investigating and researching major geotechnical failures is essential to enable these unusual circumstances to be anticipated. In the past, severe unanticipated events may have been treated as natural events or ‘acts of God’. However, society now has much greater expectations and it is essential to have policies and procedures in place that enable appropriate management of these rare, high-consequence risks. A good example is the Global Industry Standard on Tailings Management (GISTM), which was introduced after the catastrophic dam collapse at Vale’s Corrego de Feijao mine in Brumadinho, Brazil. The address will explain the concepts of uncertainty and variability, and how they should be taken into account in geotechnical design. The challenges facing geotechnical engineers, mine owners, and managers will be discussed. referencing a number of real case studies.

Sep 6, 2023

By C. M. D. Majola, K. E. Langerman

Energy efficiency is a cost-effective way of both bolstering energy security and limiting the harmful effects of energy use on the environment. Mining is an inherently energy-intensive activity, and the 2008 revision of South Africa’s National Energy Efficiency Strategy (NEES) set a target of a 10% reduction in energy consumption by 2015 for the mining sector. In this study, we investigate the effectiveness of the NEES in improving energy efficiency in the South African coal mining sector by surveying energy intensity at a number of operations, and analysing energy efficiency trends and energy use by process and energy carrier at an underground coal mine in Mpumalanga. Most mines surveyed exhibit an increase in energy intensity over time. At the case study mine, the increase was primarily due to increased energy use in the beneficiation and discard reclaiming processes. Trends in energy consumption are a poor reflection of trends in energy intensity, as a decline in energy consumption is most easily achieved by reducing production. A more appropriate metric for energy efficiency at coal mines is energy intensity, defined as energy use per unit of saleable product, relative to a multi-year baseline. The evidence suggests that the NEES has been ineffective in promoting energy efficiency in South African coal mines. We propose that greater success could be achieved by monitoring and reporting on energy intensity at the process level, and by incentivizing energy efficiency gains.

Sep 6, 2023

By T. Uysal

Various morphological parameters that affect the flotation recovery of sphalerite were modelled and optimized using the response surface method (RSM). The effects of roughness value, shape factor, and collector concentration were investigated using the central composite full design method. The results were evaluated by analysis of variance. The optimum roughening time was found to be 25minutes, the optimum roughness value was 2.9071 μm, and the optimum collector concentrationwas 0.001 M. Using these values, a flotation recovery of 98.01% was obtained. Similarly, in shapefactor studies, the optimum grinding time was 15 seconds, the optimum roundness value 0.7421, and the optimum collector concentration 0.0009 M, which resulted in a flotation recovery of 94.30%. The average error between the optimization results and the experimental results was estimated to be less than 6%, and the R2 values were greater than 90%. The study shows that RSM can be effectively applied in finding the economic optimum condition for obtaining maximum flotation recovery with minimum reagent consumption.

Sep 6, 2023

By K. E. H. K. Ishak, S. R. M. Zan

Cement production requires significant energy, and entails high costs and CO2 emissions. This is because the clinker requires very fine grinding. Grinding aids can improve production and fineness and decrease energy consumption by reducing the agglomeration of particles and protecting the balls and liners in the mill. In this study we compare the effects of three different grinding aids on clinker grinding using a ball mill. A commercial grinding additive, triethanolamine (TEA), and two industrial grinding aids (GAA079 and GAA088) were compared by ball milling tests, with additions of 0.05, 0.25, 0.50 and 1.00 wt%. The industrial grinding aids were characterized using gas chromatography-mass spectrometry (GC-MS). Particle size and morphological analyses were performed using SEM and XRD. The best results were obtained with 0.25% GAA088, which has a higher active component of diethanolamine isopropanolamine (DEIPA) than TEA. The unique combination of TEA and DEIPA in GAA088 enhances grinding efficiency and significantly improves the particle size distribution compared to TEA alone.. The grinding aids produced smooth rounded particles, which have a smaller specific surface area, enhancing the quality of the cement. XRD showed no significant structural distortion with or without grinding aids, and it was also found that the grinding aids helped decrease ball coating during grinding. The use of grinding aids can significantly improve clinker production and fineness while decreasing energy consumption, which can help reduce the costs and CO2 emissions associated with cement production.

Sep 6, 2023

By W. C. Joughin

Modern soil mechanics is generally considered to have begun in 1925, when Karl Terzaghi published his book Erdbaumechanik auf bodenphysikalischer Grundlage (Earthwork Mechanics based on the Physics of Soils). These theories were applied to rocks more than 20 years later and the science of rock mechanics became established. Methods of analysis and design have been introduced and applied, and have evolved over time. More recently, the rapid growth in computing power has resulted in more sophisticated analyses, and together with improved monitoring techniques, our understanding of geomechanics has grown considerably. Despite this, geotechnical failures with major consequences still do occur. This is partly due to failure to transfer and apply the knowledge that has been gained, but also there are aspects of geomechanics that are not well understood.

Sep 1, 2023

By Yuting Xue, Lihong Zhou, DAVOOD BAHRAMI

The paper discusses the use of machine learning (ML) to develop a predictive model for determining the location and size of underground mine fires using simulated ventilation data. The study highlights the importance of prompt fire location determination for effective firefighting strategies and reducing injury risks. The ML model was trained with simulated data and achieved an accuracy score of 0.920, which improved to 0.962 by grouping closely connected airways.

Sep 1, 2023

By Yang Song, Li Shaokang, Wang Zhiqiang, Wang Jinjun, Li Guofeng, Su Meixuan

The paper investigates the triboelectric charging properties of calcium carbonate (CaCO3) particles under different conditions using a cyclone tribocharger. It explores the effects of airflow velocity, tribocharge material, and particle moving distance on the charge-to-mass ratio of CaCO3 particles. The study aims to provide guidance for the design of triboelectric separation systems for magnesite.

Sep 1, 2023

By Brendan Demich, Brendan Macdonald, Timothy J. Orr, Jonathan K. Hrica, CASSANDRA L. HOEBBEL, Jason Navoyski, Jennica L. Bellanca

The paper describes the process of collecting detailed accounts of near-miss incidents and turning them into impactful visual stories using graphic simulation. The aim is to create high-quality training materials to reduce haul-truck-related accidents and fatalities in mining.

Sep 1, 2023

By Dion Weatherley, Raúl Castro, RENE GOMEZ, Pablo Cid

The study examines the impact of different drawbell geometries on hang-ups during ore extraction in underground mining. Using the discrete element method, the research compares three drawbell geometries: drawer, circular, and El Teniente. The findings indicate that the El Teniente geometry experienced more hang-up events, while the circular geometry had fewer.

Sep 1, 2023

By Amy McBrayer, Andrea Brickey

The paper discusses the mine planning methods used in the Powder River Basin (PRB), highlighting the differences from open-pit metal mines. It emphasizes the need for agile mine operations due to changing commodity markets and the challenges faced by the coal industry, such as volatile prices and reduced engineering manpower. The study includes a survey of mine engineers to document current practices and identify potential improvements.

Sep 1, 2023