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By H Kim, M J. Sun

Global steel companies are actively combating climate change by reducing carbon emissions. Traditional steel production, using the blast furnace (BF) – basic oxygen furnace (BOF) process, heavily depends on coal and emits substantial CO2. To mitigate this, companies are transitioning to the more eco-friendly DRP (direct reduction plant) – EAF (electric arc furnace) process, which lowers CO2 emissions. This study quantitatively evaluates the impact of increased hydrogen consumption on the carbon footprint of product (CFP) through an analysis of direct reduction process heat and mass balances. The study prioritises a comprehensive material balance based on mass conservation principles. The heat balance is calculated using differences in enthalpy through state energy properties, avoiding heat consumption. Validation using operational data from Hyundai Steel Dangjin works’ blast furnaces shows close alignment between calculated results and actual data, with less than 1 per cent error. This methodology facilitates a detailed analysis of the direct reduction process, offering insights into its feasibility and efficiency. Analysis of the operational impact by increasing the hydrogen ratio demonstrates reduced CO2 emissions and increased heat requirements due to the endothermic nature of hydrogen reduction, in contrast to the exothermic CO reduction. Possible solutions include raising reducing gas temperature or enhancing flow rate. The study effectively utilises designed heat and mass balances to assess material quantities and thermal balance under different operational conditions. It lays the foundation for the initial direct reduction process design, aiding in deriving and optimising operational parameters. Additionally, it provides valuable insights into the challenges of increased hydrogen, contributing to the production of greener steel by addressing these issues.

Aug 21, 2024

By J Furtney, W Fu, D Nutakor, A Brose

Rock blasting outcomes are often a shared responsibility of both the mine operations group and the mine geotechnical group. From an operational logistics and planning perspective, blasting concerns include optimal fragmentation for subsequent crushing, ensuring the blast is energetic enough to allow easy digging, and understanding the effect of muck from a previous blast on the current blast. From a geotechnical perspective, wall damage and catch bench capacity are the primary concerns. Other concerns for both teams include damage to mine infrastructure by fly rock or blast-induced vibrations, and the stability of open stopes under the pit. This work presents two blast modelling applications (or ‘apps’). The basic app instantly gives fragmentation and wall damage predictions for a given generic blast design. The advanced app loads the current pit contours, reads the blast design from a spreadsheet, and calculates the expected vibration magnitude and peak frequency. The apps have been developed specifically for the Rio Tinto Borates and Lithium Mine in California and are used to support blast design between the operations group and geotechnical group. The basic app instantly gives fragmentation and vibration predictions given a blast design by combining the Kuz-Ram fragmentation model with the scaled distance model for vibrations. The advanced app uses the signature hole method. Blasting outcomes at the mine have improved since using the apps.

Jun 22, 2022

By N LaBranche

The resurgence of Silicosis and Coal Worker’s Pneumoconiosis (CWP) in coalmines has placed the spotlight back on the management of worker exposure to particulate matter across all mining sectors (Coal Workers Pneumoconiosis Select Committee, 2017). There already exists a substantial body of knowledge on particulate matter and its impacts upon human health (National Academies of Sciences, Engineering, and Medicine, 2018). The contribution of silica to respiratory disease is well known and there is a growing concern for exposure to diesel particulate matter. However, it is also clear that there are major gaps in our understanding. In part, those gaps relate to the contribution to adverse health effects of mineralogical constituents in the dust (LaBranche et al, 2021a). It is also becoming evident that the size and shape of the particulate matter can affect its potential impact on human health.The University of Queensland has developed a methodology for characterising respirable and inhalable dust samples using scanning electron microscopy. Multiple samples from numerous mining operations have already been analysed using the UQ methodology. The process has been successful in showing the variety of mineralogica lcomponents and particle size distributions presentin various areas of the mines.

Oct 12, 2022

By A Specht, A Müller, V Montenegro, S Winkler, E Klaffenbach, A Schmidt

In the process of primary copper smelting in flash smelting furnace (FSF), the ratio of iron to silica (Fe/SiO2 mass ratio) primarily determines the slag viscosity and magnetite formation. Viscous slag does not only cause difficulties in daily operation, such as in tapping, it also increases the copper losses to slag. Thus, keeping the Fe/SiO2 mass ratio at the desired level is an important aspect of FSF and slag cleaning furnace (SCF) operation. In this study, the improvement of the Fe/SiO2 mass ratio was conducted in two steps: First, the optimal Fe/SiO2 mass ratio was derived based on thermodynamic data. Based on this analysis, appropriate control limits were determined. Second, this range of favourable Fe/SiO2 mass ratios was implemented into operation by an advice-based control system, which suggests the addition of silica based on the analysis of SCF slag. As this approach was successful, the same advice-based control system principle was adapted for the coke addition to the SCF. After testing the new advice-based control for several months, the production data confirm the predictions by thermodynamics: since the prediction was implemented as an advisor, the copper and magnetite content in SCF slag is significantly reduced and viscous slag is reported less often by operations.

Aug 21, 2024

There are still vast areas of Australia in which either the hydrocarbon potential has already been indicated but from which no hydrocarbons have been produced or else are completely untested. Despite the lack of recent new oil discoveries, it is anticipated that initial gas discoveries in these areas will be followed by oil discoveries as has happened historically. General exploration activities are continually providing new information that is being input to update previous hydrocarbon assessments for Australia, and all indications are that future exploration efforts will discover a lot of gas, some small oil pools and there is a chance to prove a major new oil province. Because of this, it is anticipated that reserves growth will continue at the average historical rate of about 200 MMB/year until the year 2000. The most frequent scenario will be costly exploration resulting in small oil discoveries and high development costs. This, in the past, has resulted in low profitability for Australian oil exploration, but windfalls for the Australian government.

Jan 1, 1981

The mineralised members of the Brockman Iron Formation mined at Mt Whaleback are overlain and underlain by shale horizons. To maximise resource recovery, waste movement within the life of mine plan includes mining of the:unmineralised banded iron formation (BIF), Mt Whaleback Shale, Mt McRae Shale, Mt Sylvia Formation, and parts of the Wittenoom and Jeerinah Formation. With the exception of BIFs, all other units contain zones with varying amounts of sulphides and carbon û æreactive shaleÆ. Reactive shale has a propensity to self-heat and can react with some explosives, resulting in spontaneous explosion. Sulphide rich zones also have the potential to generate acid rock drainage (ARD). Mining reactive shale at the Mt Whaleback mine must be undertaken in a safe, efficient and environmentally responsible manner. Key tasks in the mining process include:100 per cent identification of blastholes that may contain reactive shale; 100 per cent correct loading of blastholes with specified blasting products; 100 per cent of reactive shale mined, hauled and dumped in designated overburden storage areas; 100 per cent containment and treatment of ARD water onsite; and ongoing research into ARD, self-heating and spontaneous combustion. Successful mining of reactive shale requires constant co-ordination between the geology, mine planning, mining and environment departments.

Jan 1, 2002

By N Trabelsi, D Bakun-Mazor, Y Ben-Ari

As part of a comprehensive project to develop a remote sensing tool for evaluating the mechanical properties of rocks, one must obtain a rapid indication of these properties using conventional field methods. A common method for evaluating the mechanical properties of rocks in the field is to use a Schmidt hammer, a portable device that measures the rebound (R) of a spring-loaded mass impacting against the rock surface. Since the 1960s many studies have been made to find empirical correlations between the R value measured by the Schmidt hammer and mechanical and physical properties such as uniaxial compressive strength (UCS), elastic modulus, density, and porosity. Despite the existing correlations in the literature, this work is required to establish detailed empirical relationships for the carbonate rock units in Israel. To do so, 150 rock samples were collected from 38 different outcrops of carbonate rock units. In each outcrop, 20 impacts were made using a Schmidt hammer at different but adjacent points. The impacts were done horizontally perpendicular to the vertical rock walls. In the laboratory, we measured the density, effective porosity, water absorption, UCS, and elastic modulus. The rock samples we selected contained a wide range of UCS: from 7 to 270 MPa. Our empirical correlations indicate an exponential relationship between R and UCS and the elastic modulus, and linear relationships between R and density, porosity, and water absorbance. The most reliable index is the average of the five maximum impacts out of the 20 made in each rock outcrop. The correlation equations obtained from this work will make it possible to effectively evaluate the mechanical properties of the intact rock in the field, thereby aiding development of advanced tools for rock mass characterisation by means of remote sensing.

Nov 29, 2022

By P Craig, M Holden, C Zhang, D Foster, J Oh, S Saydam, J Liu, H L. Ramandi, S Akdag

High stress in rock masses can cause significant instability problems such as squeezing deformation in soft rock and rock bursts in hard rock. The support system applied in burst-prone areas in high-stress conditions is required to be able to carry high load and accommodate large deformation of the rock mass without experiencing any serious damage. Yielding support systems are promising to provide support for both squeezing and burst-prone rock mass encountered in mining or tunnelling at depth. They are ideally strong and stiff initially and then ductile after yielding (Potvin and Hadjigeorgiou, 2020). With respect to support design, a ground support system has to create a safe working environment under both static and dynamic loading conditions by providing the functions of reinforcing, retaining, holding and connecting elements (Cai and Kasier, 2018). Rigid rock bolts and cable bolts perform reinforcing and holding functions of a ground support system. In highly fractured ground or with large excavation spans (eg at roadway intersections or in caverns), unstable ground depth can exceed the length of typical rigid rock bolts (ie greater than ~3.0 m). In such cases, flexible cable bolts are needed to tie the reinforced and retained rock mass back to deeper and more stable rock. The flexibility of cable bolts allows anchor lengths greater than the tunnel opening that would otherwise restrict rigid bolts. Cable bolts also offer higher strength to weight ratio, with tensile strengths 2–3 times that of standard rebar bolts. This high strength comes at the cost of lower strain tolerance, typically around 5–7 per cent at break. Despite the lower strain tolerance, cable bolts are often used as dynamic support in demanding burst-prone ground conditions. The lower strain tolerance is compensated by allowing sufficient free length for stretching or incorporating a yielding device. There are a number of dynamic cable bolts available on the market and a number of testing campaigns have been undertaken to quantify the dynamic performance of these cable bolts. This paper reviews the existing range of dynamic cable bolts and discusses the potential areas for improvement and further research.

Nov 29, 2022

By P Mugebe, M Yahyaei, M S. Kizil, R Low

This paper seeks to establish an empirical relationship between the impact of mining technological innovation implementation and a company’s market value. The company’s market value is represented by its stock price. In a bid to ascertain the relationship, a stock price prediction model is sought to be established using the firm-specific factors impacted by the implementation of innovative technology. This work is performed under the watch of the prevailing macroeconomic factors. The background anchors in the understanding that the difference between the economic status of a mineral deposit and its uneconomic status lies in the level of mining technological innovation most prevalent at a given time (Hartwick, Olewiler and Preuss, 1986; Wellmer and Scholz, 2017; Wright and Czelusta, 2003). This is derived from productivity improvement, resulting in sustainable profitability due to technological innovation. Unfortunately, there is not an adequately established relationship that links this technological innovation impact to the share price performance of the mineral commodity company.

Sep 1, 2024

The exploration industry generally has a low opinion of the quality of the service supplied to it by government departments. In particular, the academic research-related emphasis of the Bureau of Mineral Resources (BMR) and the relatively low level of explora- tion assistance offered by several Mines Departments are of concern. In a number of areas of geoscience research, the industry perceives a mixup of priorities and a lack of understanding on the part of governments as to its needs. While government's sights are, and should be, set on the future needs of the community at large, the industry doubts that government budget allocations to the BMR and Mines Departments are either large enough or being cost-effectively spent. This is certainly the case for such areas as exploration assist- ance, provision of basic exploration data, and applied geoscientific research. On balance, the exploration industry's perceptions are misguided in a number of respects because of a lack of communication with government. However, this reinforces the need for changes in the manner in which govern- ment departments communicate with industry and, in particular, the criteria upon which research priorities are based. At a time of contracting oil and mineral exploration expenditure, and near-record levels of geoscientist unemployment, the government's role is critical and should be open to question.

Jan 1, 1986

By G J. Showers, P Botman, A G. Hunt

Iron Road Limited (Iron Road) is currently evaluating the feasibility of producing 21.5 Mt/a of high-grade (>66 per cent Fe) magnetite concentrate from a 3.7 Bt resource (JORC) located at Warramboo on the central Eyre Peninsula in South Australia. Bulk concentrate can be produced via a conventional grind and low-intensity magnetic separation flow sheet. Due to the comparatively coarse magnetite liberation size (106 µm), consideration was given to enhancing both the grind economics and coarser product sizing via gravity separation.This paper outlines the test work, flow sheet design and engineering design of a gravity beneficiation circuit (GBC) conducted by Mineral Technologies for Iron Road. The resulting circuit optimisation necessitated mass balance simulation by Iron Road’s SysCAD model to quantify the resulting changes in mill recirculation load. This included the determination of project-critical grinding power and energy requirements with and without the GBC installed into the primary ball mill classification circuit. The outcome of this work was the design of a GBC, including spirals and up-current classification, which led to a substantial reduction (33 per cent) in ball mill recirculating load and power requirements, together with a favourable coarsening of final product size due to the relatively coarser gravity concentrate. This has led to a significant reduction in project design capital and operating costs. A further benefit of this approach is increased recovery of (paramagnetic) hematite and lesser titano-hematite via gravity separation compared to an all-magnetic separation approach.CITATION:Hunt, A G, Showers, G J and Botman, P, 2015. Test work and design of a gravity circuit for Iron Road’s Central Eyre Iron Project, in Proceedings Iron Ore 2015, pp 139–142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By R Wilson, S Luke, R Williams, B Freeburn

"In 2010, two McLanahan RSS14×50 scrubber screens were installed at Fortescue Metals Group’s (Fortescue) Christmas Creek site. By 2015, the trommel (screen) section had effectively reached the end of their serviceable life. This was determined by regular measurement of structural components over the previous 18 months that tracked wear life. At the same time, numerous trials and optimisations had taken place on screen panel design and material composition. During 2015, a new set of trommels were designed, manufactured and installed that incorporated many new features: increased open area to facilitate high throughput, improved wear protection for structural members, simplified trommel panels and realigned discharge ports to reduce wear on exit. Numerous other upgrades have taken place on the drive system, feed chutes, liner and weir configurations and park brake, to name a few. This paper will highlight how regular measurement drove design changes and how the site and the original equipment manufacturer (OEM) managed a replacement program that has delivered improved performance.Citation:Wilson, R, Luke, S, Freeburn, B and Williams, R, 2016. Regular Measurement Defines Upgrades on Scrubber Screens, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 285–290 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By A Roudnev, P Loderer

Mineral froth pumping utilising centrifugal slurry pumps is a major engineering challenge for both the end users and pump manufacturers. The traditional approach has been to oversize the pump for pumping mineral froth. New horizontal slurry froth pump designs offer opportunities to improve froth pumping capability of mineral froth with challenging (high) Froth Volume Factor while maintaining high efficiency, long wear life and stable pumping performance.CITATION:Loderer, P and Roudnev, A, 2018. A reliable solution for pumping mineral froth with challenging froth volume, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 291–296 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By M A. Tuck

Air blasts or wind blasts as they are termed in underground coal mining, occur in a number of types of underground mining where a void develops and the overlying or adjacent rock fails rapidly to allow the development of a high pressure air pulse. The effects of air blast vary widely from very low consequence to high consequence events causing multiple fatalities as occurred at North Parkes mine. The aim of this paper is to examine the phenomena of air blasts and the underlying parameters which determine the severity of the air blast event. A basic model under development is then detailed. The aim of the model is to determine the magnitude of the pressure pulse(s) developed during an air blast event. This, combined with a transient ventilation network analysis model will enable the airflows and associated pressure drops to be determined and allow the pressure pulse around the mine to be evaluated. The overall aim is to allow mining engineers and mine ventilation engineers to undertake a risk assessment of air blasts at individual mine sites, allowing working parameters to be changed to eliminate or reduce air blasts, or engineering controls to be developed to reduce the effects of air blasts.CITATION:Tuck, M A, 2013. Determining the pressure pulse for an air blast, in Proceedings The Australian Mine Ventilation Conference , pp 103-106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By R Berry, J Hunt, T Kojovic

Geometallurgy aids the understanding of orebody variability through the integration of geological and processing information, thereby enabling spatial mapping of processing (eg comminution or separation) performance across a deposit. In order to do this, estimates of quantitative geometallurgical attributes are needed so that continuous downhole profiles can be generated for each attribute, providing vital data for the development of processing domains through geostatistical modelling. However, as traditional comminution tests are high cost and/or require large samples, current practice typically results in insufficient data density and distribution of comminution indices making it difficult to model and map deposit scale variability. The aim of this work was to find a method to estimate comminution indices based on data that is widely available at mine sites. This data includes mineralogy and chemistry of drill core samples, plus logging information such as lithology and alteration. Work to date indicates that comminution parameters such as semi-autogenous grinding (SAG) Power Index (SPI), Bond Work Index (BWI) and A*b (Julius Kruttschnitt Mineral Research Centre (JKMRC) drop weight test (DWT) Index) can be modelled using chemical and/or mineralogical data. The estimated hardness indices can then be propagated into the mine site database and used in the definition of processing domains that map inherent variability across a deposit. The estimates can thus provide geometallurgical inputs for spatial modelling, mine planning and optimisation initiatives.CITATION:Hunt, J, Kojovic, T and Berry, R, 2013. Estimating comminution indices from ore mineralogy, chemistry and drill core logging, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 173-176 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By M Ma, W J. Bruckard, C Gontijo, R Holmes

Vale is the largest iron ore producer in the world. Since the 1970s, Vale has been using reverse cationic flotation to remove siliceous impurities from its iron ores. Whilst this flotation process has operated effectively for many years, it suffers from the problems of high reagent costs and high metal loss.In 2010, CSIRO investigated the use of a reverse anionic flotation process for Vale iron ore. Batch laboratory flotation studies conducted on Vale samples showed significantly reduced reagent costs and improved recovery of iron. In this work, the flotation behaviour of the different impurities in the Vale iron ore sample using reverse cationic and reverse anionic flotation processes is compared. Detailed flotation responses are presented and the merits of the two different flotation schemes are discussed.CITATION:Ma, M, Bruckard, W J, Holmes, R and Gontijo, C, 2013. Impurity removal in the reverse flotation of iron ore, in Proceedings Iron Ore 2013 , pp 427-430 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

Two characteristics of the modern mining industry are that there is a skill shortage and that young professional people rise rapidly into highly responsible supervisory positions. With this responsibility comes the burden of identifying and managing health and safety risks. Without the benefit of a comprehensive health and safety training program, these young professionals may be putting both themselves and those under their supervision at risk. The Moura Mine explosions and the asbestos health disaster should not be just artifacts of history, but highly valued lessons that impress the need for comprehensive health and safety risk management strategies on young professionals. From the perspective of the former secretary of the Committee to implement the findings of the Moura (Disaster) Inquiry and as the former coordinator of the Coal Workers Health Scheme, key issues in occupational health and safety management systems are explored.

Jan 1, 2005

By H J. J Boshoff

Pit lakes, as a final void after completing open cut mining, are in most cases unavoidable. Initial mine designs and approvals require consideration and assessment of closure objectives, legislation and stakeholder acceptance to ensure suitable understanding of the closure liability. Mining companies undertake studies and engineering during the planning, operational and closure stages of mining to identify closure options for the final voids, which would be sustainable. Without adequate planning prior to and during the life of the mine, options during the closure stage become limited resulting in costly closure works or long-term liabilities. Engineering consultants provide a specialist service in the assessment of long-term pit lake water levels and characteristics. Ongoing advances in mining methodology and technology, coupled with improved data collection and data management aid in a better understanding of the complexities in estimating long-term pit lake water levels and characteristics. Closure objectives developed during the planning stage sets the requirements for long-term pit lake water levels, which could require maintaining a water level and pit water or discharge water quality. A variety of approaches could be used to assess these closure scenarios each requiring specific data and methodologies. Typically, limited data is available during the planning stage, which results in assumptions based on past experience and relevant case studies. Closure assessments are revisited during the life of mine and leading up to the closure stage, during which additional site-specific data is available improving the accuracy of the assessments.CITATION:Boshoff, H J J, 2018. Assessment of approaches, data requirements and methodologies for estimating long-term pit lake water levels, in Proceedings Life-of-Mine 2018, pp 28–31 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By D R. Chalmers

Coal dust explosions have occurred in coal mines across the world. The Mitsui Miike Coal Mine disaster in 1963 was an example of how this hazard was not managed effectively, resulting in the loss of 458 lives and hundreds of people sustaining permanent brain injury from carbon monoxide poisoning. Management of the risks for this hazard have been well documented and have been implemented in modern coal mines. A recent trend in some mines has seen the abolition of barriers on roadways on the basis that the risks are being managed by the current controls. These controls include stone dust application, trickle dusters, dust analysis and dust removal. This paper explores the science behind such controls and questions the need for barrier protection on belt roads.CITATION:Chalmers, D R, 2013. Cybulski revisited - Lessons on dust, in Proceedings The Australian Mine Ventilation Conference , pp 165-168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By H Bleuler

A new portal and access drift was constructed by Concrete Constructions for BHPÆs Elouera Colliery, south of Wollongong.The portal area at the base of the Illawarra Escarpment is in soft colluvium material, underlain by highly to moderately weathered sandstone. The area has a well documented history of slope movement or slope creep and one of the main criteria for the design was to minimise disturbance to the unstable slope by limiting the excavation for the portal establishment. This was achieved by incorporating a sloped headwall and gabion wingwalls to accommodate the anticipated creep and groundwater seepage.Main features of the design process also included the provision of both primary and secondary support in a single shell application and the use of canopy tubes to provide support ahead of the tunnel face.The active involvement of the designer during the construction phase and the flexibility of the design concept allowed changes to the support methodology to be carried out as excavation proceeded.This paper describes the design process undertaken for portal establishment and access drift to cater for the variability of the exposed ground conditions along the drift alignment.

Jan 1, 1999