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By C Dick

Over the past three decades, mining operations have seen a significant increase in the use of contractors for mining, camp management and catering, recruitment, maintenance, power management, and commissioning. More recently contractors have been engaged for stores and logistics, OH&S, environmental, exploration, training etc. In some countries, such as South Africa, the trend is towards total outsourcing of all aspects of a mining operation which is coordinated by the owners’ management team.During the Global Financial Crisis (GFC) more Australian companies considered and/or took on this approach to recruiting for both projects and operations as mining companies were forced to rethink their corporate strategies as commodity prices plummeted to low levels, pushing operations and projects into potentially financially unviable territory.This paper discusses the labour recruitment, commissioning and operating strategy of Western Areas NL (WSA), with the assistance of Independent Metallurgical Operations Pty Ltd (IMO), as it progressed construction, commissioning and operation of the Cosmic Boy nickel concentrator at the Forrestania Nickel Project during and post GFC. The use of IMO contractors allowed Western Areas to mitigate labour cost risk during the uncertainty caused by the GFC and let their management team focus on the task of bringing a new operation into viable and profitable production.

Aug 8, 2011

By B Laidens, D Souza, W Bielefeldt

The CaO-MgO-SiO2-Al2O3 system, characterised by its intricate phases and thermodynamic properties, plays a pivotal role in steel secondary refining processes, encompassing desulfurisation, non-metallic inclusion capture, and refractory protection. Accurate predictions for diverse industrial applications, including metallurgy, ceramics, and materials science, are imperative. To address this challenge, a combination of machine learning techniques will be specifically applied to model the liquid fraction of the slag and the solid fraction of MgO. The development of an artificial intelligence (AI) system, leveraging various machine learning techniques, has gained momentum in this project. The focus of this work is on constructing an AI model, based on machine learning techniques, within the CaO-MgO-SiO2-Al2O3 system, utilising simulation results from FactSage™, version 8.1 (by GTT Technologies). The primary objective is to train the AI model using these simulation outputs to predict the percentage of liquid fraction and MgO saturation based on chemical composition parameters. The AI model will undergo training with a comprehensive data set of simulations within the CaOMgO- SiO2-Al2O3 system, covering a diverse range of compositional at 1873 K. These simulations, conducted through FactSage™ 8.1 software, provide a robust foundation for AI model training, ensuring generalisability and precise predictions for the liquid fraction of the slag and the solid fraction of MgO, the solid fraction of MgO in this case is determined by the difference between the total MgO and the MgO in the liquid fraction, so it is not the objective of this study to determine which phase of MgO is in the solid state.. The predictive capabilities of this AI model hold significant implications for process optimisation, quality control, and decision-making in CaO-MgO-SiO2-Al2O3- dependent industries. Precise estimations of the liquid fraction and MgO saturation empower researchers and engineers to enhance operational efficiency and quality. This paper explores the methodologies employed for AI model creation and training, achieved results in terms of prediction accuracy, and potential applications in the field. The development of this AI system signifies a notable advancement in utilising machine learning for better comprehension and control of complex chemical systems. Furthermore, to align the study with real-world steel production, we introduce FeO and MnO at concentrations of 2 per cent and 1 per cent at 1873 K, respectively, following the validation of model results using the CaO-MgO-SiO2-Al2O3 system. This adjustment aims to bring the study closer to the observed reality in steel mills globally.

Jun 19, 2024

By J Li

Cannington Mine has been developing through paste backfilled stopes since the year 2000. These paste drives have been used as either production drill accesses or long-term bypasses. Prior to this study, the ground support requirements for each paste development cut were: an initial 50 mm layer of fibrecrete, weld mesh bolted with 2.4 m split sets, followed by a second coat of 50 mm fibrecrete. Both layers of fibrecrete and the layer of mesh were to be installed before the next cut could be bored and fired. This support regime proved successful at Cannington, however, the total cycle time for each cut was lengthy due to the installation and curing times associated with each layer of surface support. In an effort to reduce the cycle time a study was carried out, with the aid of RocScience’s Phase2 numerical modelling software. The modelling reviewed all of the parameters controlling the stability of a newly excavated development cut. The parameters studied included the early strength of fibrecrete, the ground support load capacity, and the strength of the paste fill masses which varies depending on the cement content. As a result of the study, the ground support standard was revised. The revision has significantly decreased the cycle time as well as fibrecrete consumption, all the while maintaining the safety of personnel and equipment.

Mar 21, 2011

By G A. Blengini, S V. èolar

The minerals industry is faced with choices beginning in the exploration phase and extending over the life cycle of the mine. Firms examine the technical feasibility of alternative actions and typically rank them based on economic performance. Increasingly firms also consider alternativesÆ contribution to sustainable development. There are many visions of what a sustainable future should look like and much debate about what should be sustained. Sustainability is a process, a series of incremental actions, and each alternative course of action has the potential to further progress toward one or more sustainability goal. However, because it is not possible to sustain everything everywhere simultaneously, trade-offs and choices inevitably have to be made.Sustainable decision making before investment (ex ante decisions) should incorporate a broad suite of quantitative and qualitative information. One approach is to utilise an integrated sustainability assessment (ISA) framework that supplements traditional technical and financial tools with other tools such as objectives hierarchies (OH) and life cycle assessments (LCA). OH is a problem framing method that captures stakeholder and decision maker interests, objectives and values. LCA addresses material and energy flows, and environmental impacts. The outputs of these tools can be combined with additional qualitative measures and analysed using multi-criteria decision analysis (MCDA). MCDA models facilitate comparison of different alternatives on the basis of a set of criteria and indicators. Some can incorporate information on risk attitudes and preferences ( multi-attitribute value theory models) and others uncertainty about outcomes (multi-attribute utility models). Studies have been published describing and comparing tools for minerals sector decision analysis. Our paper extends this literature, discussing how a combined OH-LCA-MCDA can support ex ante sustainability assessment by incorporating preferences, risk attitudes, and monetised or non-monetised social and economic variables, in a manner that captures their inherent complexity. We also discuss how such a combined model would support trade-off analysis.

Jan 1, 2009

By R Halatchev

Production scheduling optimisation in open pit gold mining is a complex problem as it is driven by economic criteria reflecting particular economic interests of the concerned parties in the mining business. The contemporary organisational forms of mining, such as owner-operator and contract mining, are a good example of this relationship. These forms are complex and contradictory by nature as the contractor aims to get more waste at the beginning of mine exploitation in order to make more profit with favourable discounting effect over time, while the owner-operator aims to mine less waste at the beginning, which is a precondition for implementation of the mine planning principle of waste deferment and maximising the net present value (NPV) by accounting for the time value of money. Both forms are vital for the successful performance of the Australian mining industry as their competition is a powerful driving force of the market-oriented national economy.The present paper offers a new vision about the economic effectiveness of contract and owner-operator forms in surface gold mining through the prism of a novel production scheduling approach with a multistage stabilisation of the mining rate that implements the mine-to-market concept of modelling. The comparison of the forms is demonstrated with a case study that reveals the specific features of the new scheduling approach and the benefits of its implementation in the exploitation of Australian gold resources.CITATION:Halatchev, R, 2013. Owner-operator versus contractor production scheduling - a vision for the effective exploitation of Australian gold resources by surface mining, in Proceedings World Gold 2013 , pp 255-266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By G Davison, C Rossimel, M Bouazza

Expanding rock bolts anchor within a rock mass more efficiently than non-expanding varieties. This is of great importance in weak ground conditions, where grouted friction bolts perform less efficiently than in good ground conditions. Filling a Split Set with demolition concrete has been shown to double the load-carrying capacity when compared to conventional use of Split Sets. This report details verification of these results by installing and pull-testing 14 Split Sets of varying grout conditions within in a fault zone. These Expanding Split Sets achieved loads double and triple that of ungrouted and normally grouted conventional Split Sets. A literature review and chemical analysis were conducted to understand the expansion process better. It was found that 20 per cent more calcium is included in expanding cement, which is responsible for its growth. Factors most affecting the expansion process were identified. Furthermore, the expansion rate of a bolt outside a borehole was measured and 6 mm of expansion across its diameter was found. The compressive properties of the cement were compared with other types, due to expanding cement becoming uncohesive after the expansion process is complete. When confined within a Split Set, compression testing demonstrated that this grout is just as strong and rigid as normal grout. Finally, the bolts were tested by shear and it was found that the Expanding Split Set (ESS) has a similar shear capacity to grouted Split Sets, which is 70 per cent higher than that of ungrouted Split Sets. These results enabled the mechanism for improved performance in weak ground conditions to be verified. Expanding grout will expand the Split Set into its borehole of varying diameter and lock it into place, creating increased friction and resistance to pull-out. This paper shows that ESSs can be a useful reinforcement technique in weak ground conditions.CITATION:Rossimel, C, Davison, G and Bouazza, M, 2014. An investigation of expanding split sets in weak ground, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 159–170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By N Esmaeili, M Saghaeian, L Hosseini, V Sheikhzadeh, R Hejazi

Ore roasting has long been used for beneficiation and assay upgrading of different ores. In this process, which is mainly used for sulfide ores, the ore is heated to a high temperature. More specifically, it is a metallurgical process involving gas-solid reactions at elevated temperatures. Some types of Iron ore are weak in magnetic properties. Hematite, goethite and limonite are classified in this group. Unlike magnetite, which shows strong magnetic susceptibility, these ores are hard to beneficiate through magnetic separation route. Many researches have focused on gravity separation and flotation routes for upgrading these ores and these methods have also been utilised in the industry. One of the methods to whose industrial application less attention has been paid is magnetising roasting in which the non-magnetic iron ore is transformed to magnetite which is further beneficiated through magnetic separation. In this study, magnetising roasting tests have been performed on one goethite sample in order to check the feasibility of using this method for this specific ore in industrial scale. It is worth mentioning that high intensity magnetic separation have been performed on this sample before but the achieved results were not promising. Results have revealed that through magnetising roasting magnetite content of the ore could be increased from 1.7 per cent up to about 25 per cent. FeO content of the feed sample was increased from 1.03 per cent up to around 9.25 per cent. Also optimum size distribution for achieving the best results in magnetising roasting for this sample has been determined through this study. The best results were achieved when the ore size was 0–10 mm. The effect of coal ratio, time and temperature on the process have also be studied. A coal ratio of 5 per cent, time of 30 min and a temperature of 850°C were determined to be the optimum conditions. Finally, the technical feasibility of utilising magnetising roasting for this specific ore has been confirmed.

Aug 24, 2022

By J L. Kerr, J Beyer-Robson, S Vink

Driven by an increasing need for water conservation, coal mine operators in the upper Isaac River catchment have placed significant emphasis upon the reuse of water. This initiative led to an overall increase in the salinity of mine waters. The ionic composition of this water differs from local stream water in that concentrations of sulfate are higher than average stream concentrations by ten per cent, while concentrations of bicarbonate and calcium are lower. When this water is discharged into ephemeral streams in semi-arid environments there is potential for this increased salinity and altered ionic composition to impact upon the ecosystem processes mediated by micro-organisms in river sediments.We have measured nitrification, denitrification and methanogenesis rates in a series of lab experiments using sediments from Isaac River catchment streams and found that salinity affects these processes in different ways and to different degrees. Process rates were shown to differ seasonally between samples taken from the same location and habitat type and also between different habitat types at the same time and location. Both aerobic and anaerobic process rates were higher in surface sediments and it is likely that this activity is associated with surface biofilms. Furthermore, we have shown that the ecosystem processes we have measured are limited by the availability of carbon in the sediments.The management implications of these findings for mine releases into ephemeral streams will be discussed.CITATION:Kerr, J L, Vink, S and Beyer-Robson, J, 2013. The effects of increased salinity on microbially mediated ecosystem processes in ephemeral streams, in Proceedings Water in Mining 2013 , pp 121-134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By J J. L du Plessis, S Viviers, G Ratner

Escalating electricity costs are one of the biggest operational cost drivers in mining. The trend to use high-powered auxiliary fans delivering increased airflow to meet the dilution requirements of diesel equipment, together with the reliance on ducted systems rather than traditional flow-through systems to ventilate areas, increases the overall energy requirements of ventilation systems. To manage and reduce electricity costs energy management systems can be implemented, inefficient operating units can be replaced and the operation of energy-consuming components of ventilation systems can be optimised.This paper describes the process followed to design and develop an energy-efficient axial flow auxiliary fan. The fan-targeted design was based on static pressure and volume flow rate requirements incorporating higher overall fan efficiencies. A brief overview of the results is given, including the aerodynamic design procedure using computational fluid dynamic (CFD) analysis. The mechanical design criteria used, including stress analysis on the rotor and designs to improve the vibration levels of the fan, are also presented. Through this study it was demonstrated that the aerodynamically designed rotors using profiled and twisted blades improve the total fan efficiency considerably when compared with some of the older-generation fans using cambered plates. The latter were typical in the mining sector in South Africa at the time of the study where average overall fan efficiencies of standard cambered fans less than 63 per cent and some of the older-generation cast aluminium blades have peak overall fan efficiencies of about 65 per cent. Peak overall fan efficiency of more than 80 per cent was achieved by using the described design and development process. Additional benefits are that the fans are quieter due to the better aerodynamic design and have a longer operating life due to reduced vibration levels.In conclusion, the use of CFD to develop fans to deliver the required volume flow at the required pressure allows quicker design turnaround time. It furthermore allows the ventilation engineer the option to specify a specific fan and is not limited to an off-the-shelf catalogue fan. It thus allows engineers to purchase a fit-for-purpose energy-efficient fan. The introduction of reliable fan control systems may, however, still result in the biggest cost benefit for underground mines.CITATION:du Plessis, J J L, Ratner, G and Viviers, S, 2015. Design and development of energy-efficient secondary axial flow fans, in Proceedings The Australian Mine Ventilation Conference, pp 337–344 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By D Laurence, L Ge

This paper demonstrates use of remotely sensed imagery in promoting sustainable mining. Remote sensing technology can be used during all phases of a mining project û from evaluating the resource, to making extraction more cost-effective, through to monitoring, mine closure and remediation. Use of the new generation of satellite platforms with the capability of acquiring satellite data with higher spectral and spatial resolution have the capability to emerge as essential indicator for sustainable development in the minerals industry. A life cycle approach to satellite imagery is discussed. The use of an imagery of the site prior to mining activity establishes the environmental baseline, guides mitigation measures and eventual help in suggesting remediation. Remote imagery provides the cost-effective means of monitoring reclamation, including the growth of planted vegetation, of the mine site and surrounding area. The latest advancements in satellite remote sensing are highlighted to meet the newer challenges of sustainable mining practices. Some of the worldwide successful remote sensing applications for the measurement and evaluation of the sustainable development impact of mining operations are described. Presently available source of imagery and its comparative advantages and disadvantages are provided as a guide. Finally, the limitations of this tool are indicated.

Jan 1, 2009

By C Harwood

Underground coal mines in the United States are in the process of completing installations for tracking and communication systems, mandated by Congress after a number of recent coal mine disasters. Yet, evaluation, modelling and testing of such systems has lagged due to legislated changes, abruptly introduced into the coal mining industry. System installation in a wide array of mine types, configurations, layouts and characteristics has provided a wealth of information regarding their potential in underground environments. Data collected from numerous installations for a variety of systems can be used to further define true capability and accuracy of communication and tracking packages. This paper describes a uniform means of evaluating the performance of a communication and tracking system. Several performance measures are proposed and described. These measures can also be predicted using an interactive software program. This program predicts the signal propagation, given the input mine characteristics and layout, with numerical and visual feedback. New or alternative system installations can also be more accurately designed to potentially minimise initial system cost and time required for trial and error installs. The focus of this research is to develop tools and protocols that can evaluate and measure the effectiveness of installed underground communication and tracking systems.

Nov 22, 2011

By J Penman, N Turner, H Liu

This paper aims to present a snapshot of the risk profile for tailings storage facilities within Western Australia by comparing the spatial distribution of known facilities against common geohazards such as cyclonic activity, climate, and peak ground accelerations from earthquakes. The analysis also includes an assessment of proximity to populations at risk including towns and sensitive receptors including significant river systems and wetlands.

Jul 1, 2021

For the mineral industry, sustainability seems to mean socially positive and ecologically neutral mineral extraction. Mines are financed and developed in response to demand for their products. The purpose of my paper is to indicate the potential dimension of demand. As part of an unrelated study which I undertook ten years ago, it became apparent that there is a persistent relationship within communities between infant mortality and mineral use; greater mineral use corresponds to a lower rate of infant mortality. This comes as no surprise; sufficient potable water, a reliable supply of food, hygienic waste disposal, hot water and refrigeration all improve the chances of survival of the more vulnerable members of any community. The predictable provision of these facilities requires the application of minerals. This relationship is supported by a table (Appendix 1) included in the UNICEF publication, æThe State of the WorldÆs Children 2001Æ. This table lists regional infant mortality rate (IMR) statistics from around the world, including a listing for æindustrialised countriesÆ. Such countries experience an IMR lower by an order of magnitude than any other region. æIndustrialisedÆ inevitably involves the use of metallic and energy minerals. The principal use of copper is in the generation and distribution of power; it is fundamental to any industrialisation. IMR is a valuable connection because it quantifies caring for the young, a vital strategic driver of human behaviour independent of time, place, fashion or economic circumstances. I have tabulated the population, IMR and the copper demand per head of population for countries containing over 99 per cent of the population of the world in the years 1950, 1960, 1970, 1980, 1989, and 1999. These countries have been consolidated into four groups, Very High, High, Medium and Low rates of infant mortality (UNICEF has used this terminology; the Low group includes all the æindustrialised countriesÆ). The purpose of this consolidation was to reduce the volume of work, to dampen out the impact of regional wars and business cycles, and to dampen out the variable quality of information. Based on the pattern of the copper demand, population and IMR over the last 50 years, I have projected the likely copper demand in 50 years time. A dominant feature of my tabulation is the increase per decade in copper use per head and a corresponding reduction of the IMR. The word æuseÆ is preferred to æconsumptionÆ because it is estimated that over 80 per cent of all the copper ever mined is still in circulation There are two major influences at work; one is the absolute increase in population (UN estimates for 2050 are updated periodically) and the second is the movement of countries into a higher pattern of use and lower IMR. For example the Medium group in 1989 had an infant mortality rate approximating that of the Low group in 1960. With the population of the Medium group (which includes Russia and China) forecast to reach 2.6 billion in 2050, the world copper demand in that year will be significantly greater than the present figure. Nevertheless it will not be as great relatively as the increase of over 300 per cent in the last 50 years.

Jan 1, 2002

By R Salmimies

Choosing a ceramic capillary action filter is often favoured in processes where low energy consumption is important, such as the dewatering of iron ore. In addition, the performance of the filter medium is essential, and the possibility to regenerate the medium is an advantage compared to other types of filter media. Although low, roughly 8 - 9 w-per cent for iron ore concentrate, and even cake moisture is the primary goal of dewatering, the introduction of better filtration processes can result in significant improvements of water economy and material efficiency.As industrial beneficiation processes are often complicated in their chemistry due to impurities originating from the ore itself, from the up-stream processing equipment and from the process water used, the characterisation of the filter media after usage might provide relevant information on what actually takes place during long operating periods. The aim of this study was to obtain new information on the fouling of fi lter media in an iron ore process to enhance and develop the regeneration process of the media in the future.X-ray diffraction and scanning electron microscopy were used to characterise ceramic filter media used in the dewatering of magnetite. Principal component analysis and discriminant analysis were introduced to identify trends in the data. Two types of media blockages were found to play an important role in an acidic iron ore dewatering process: fouling by slurry particles and by in situ crystallisation of a calcium compound, of which the latter originated from the combination of process water and process chemistry.

Jul 11, 2011

By A Bagis

Road tunnels are an accepted and effective transportation solution in urban areas to mitigate increasing traffic congestion and facilitate improved urban connectivity in a cost effective manner while meeting societal goals to reduce the impact of construction. In designing a tunnel system, there is a requirement to achieve an acceptable level of in-tunnel air quality, as well as meeting ambient air quality goals. In Australia, there is also a requirement for zero portal emissions which means that all pollutants must be emitted to the atmosphere via a ventilation stack.Traditionally, effective pollutant dispersion has been achieved by constructing tall ventilation stacks which disperse pollutants into the atmosphere at a high level. The dominant variable parameters in the effectiveness of the dispersion under the ventilation engineers control are the efflux velocity, the height of the ventilation outlet and the concentration of pollutants at the point of discharge. During off-peak operations the required ventilation exhaust rate can be reduced due to the decrease in traffic. This can lead to a drop in the efflux velocity from the stack and therefore the effectiveness of the dispersion. This potentially drives the need for a higher outlet, or an increased exhaust rate to achieve a higher efflux velocity with consequent effects on energy consumption.The paper proposes a method of varying the cross-sectional area of the ventilation stack with the use of motorised control dampers, thereby maintaining a sufficiently high efflux velocity throughout the 24 hour period independent of traffic conditions. This allows the use of a potentially shorter ventilation stack.

Mar 8, 2011

By G Bickert

Australia is currently developing and engineering a range of specialised processing options for rare earth (RE) (Lynas, 2011, Alkane, 2005), zirconia (Alkane, 2005), lithium (Galaxy Resources, 2008) and other special minerals and metals required in high-tech applications. The processing of lithium, zirconium and RE minerals is based on complex leaching processes which require extensive liquor clarification, solid liquid separation and solids washing. The filtration properties for those leach liquors, residues and precipitates are not well understood and differ drastically according to the process route applied. Thus, filtration test work is essential for equipment selection, sizing and design. Similar types of slurries are filtered in laterite nickel, TiO2 and other chemical oriented processes, while more experience is available here as those processes are applied widely for a number of decades. The increasing need for dry stacking of tailings requires advanced tailings filtration with properties differing drastically depending on tailings properties. More traditional mineral processes such as flotation commonly apply filtration. All of these and other cases require proper filtration test work particularly evaluation of vacuum versus pressure filtration and the need for cake pressing and/or air blowing for filter presses. Bench scale test work and/or pilot plant operation is common to determine filtration rates, achievable cake moisture and wash efficiencies and sometimes filtrate clarity. While those values are important, there is much more valid information to be obtained by filtration test work.This paper discusses the intricacy of filter selection and sizing based on driving forces (vacuum and pressure air, compression by mechanical means and slurry) and parameters (cake thickness, forces and times) and different processes utilised in common filtration equipment. It will discuss the in’s and out’s of filtration test work design, planning, and in particular data gathering, processing, reporting, evaluation and filter sizing from recent examples of bench and pilot scale filtration test work for above applications together with methods for predicting filtration performance for example where test work is lacking. One focus will be the realistic extrapolation of test work results towards different parameters utilised in full scale equipment and plants. The conclusion of the paper will contain checklist for filtration test work.

Aug 8, 2011

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 B McFadzean, N P. Lima, D A. Deglon

The reverse flotation of Itabirite iron ore is typically performed after a desliming step in which most of the sub-10 µm particles are removed. This is done to limit processing problems such as poor flotation recovery of SiO2 due to slime coatings and increased slurry viscosities, unmanageable froths and increased losses of hematite particles due to entrainment. However, the rejection of ultrafine particles contributes to large losses in iron recovery and may contribute to the instability of tailings dams. The aim of this study is to decouple the effects of ultrafine particles in the pulp and froth phases to better understand the processing capabilities of the fines fraction. The flotation test work was performed in a special-purpose continuously operated laboratory flotation cell that has a deep froth section to simulate plant-scale froth conditions. Five conditions of fines addition were investigated at three different froth heights and a solids concentration of 50 per cent. The behaviour of the pulp and the froth were decoupled using froth stability and froth recovery tests. This showed that, even though there is an exponential increase in froth stability at increasing fines quantities, the performance of the pulp has the overriding effect on the overall SiO2 recovery. Pulp zone, froth zone and overall SiO2 recoveries showed that overall recoveries increased by about 3.6 per cent for every 1 per cent decrease in fines content. This meant a large increase of 20 per cent in SiO2 recovery when going from undeslimed to deslimed feed. This was driven largely by increases in the pulp zone recoveries, which were about 4 per cent for every 1 per cent decrease in fines content. The froth recoveries, on the other hand, decreased by between 0.75 per cent and 2.5 per cent for every 1 per cent decrease in fines content, depending on froth height. This paper explores further insights into iron ore flotation processing at different slimes concentrations.

Aug 24, 2022

By D Tucker, K Harney

Hatch forecasts that an increasing share of seaborne traded iron ore will be ultrafine, being either concentrate or pellet feed. This provides several challenges for the iron and steel industries, but the principal concern is: how much ultrafine iron ore can be consumed on sinter strands and with a minimal effect on productivity?This paper will identify new supply by project through 2020. Demand will be estimated for sinter production and practical steps will be identified to increase ultrafine consumption in sinter strands. The long-term iron ore price will be forecast to balance supply and demand. The paper will conclude by assessing how the pricing of ultrafine ore will develop relative to the Chinese iron ore indices.CITATION:Tucker, D and Harney, K, 2015. Iron ore ultrafines challenges and opportunities, in Proceedings Iron Ore 2015, pp 501–504 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By A Reid, A W. Musk, O Jones

In this paper, the authors attempt to bridge the gap that currently exists between the duty-of-care responsibilities of underground mining industry personnel, and the multifaceted health challenges facing mineworkers in Western Australia’s metal mines where diesel-powered mobile equipment predominate. In addressing this issue, the complexities of the nature and extent of the challenges are discussed along with the current inadequacy of existing regulatory metrics. Support is given to the need for well-organised in-mine baseline studies to clearly define the distribution and aging characteristics of the toxic and carcinogenic pollutants within the mine ventilation system, with special emphasis given to exploring the validity of biomonitoring systems. The paper concludes with the proposal that a template risk assessment data sheet be prepared for the industry to provide mining personnel with a sound basic knowledge of the health risks involved and the control measures and precautions available for minimising and/or eliminating the hazard.CITATION:Jones, O, Musk, A W, Reid, A and Davis, C, 2017. Risk assessment tool for mines using diesel-powered mobile equipment, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 151–154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017