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By P Cooper

Continuous improvement using six sigma methodologies commonly follows the DMAIC methodology of define, measure, analyse, improve and control. A key requirement in the use of this approach is to ensure that data is trusted, validated and contextual. In today’s production environments it is common to find disparate technology comprising the system architecture and highly customised interfaces between the various technology layers. This complexity often leads to inaccurate data presented at the operations management layer or worse, data that is not trusted. Identifying defects and making corrective actions cannot be efficiently carried out unless trusteddata can be easily obtained with a production context. It is also common to find that disparate systems of this nature present information in multiple ways and through multiple presentation systems. This paper discusses how the use of web-based technologies in an integrated technology stack can aid the accessibility, accuracy and trust of data used in decision-making and also how a unified visualisation environment can lead to greater operator efficiency.

Jul 11, 2011

By J Wheeler

The benefits of fine size separation in magnetite concentration are detailed focusing on published research from various iron ore producers. Basic principles of fine sizing and advancements in screening technology are addressed. A chronological review of research is used to show the evolution of fine sizing applications in the industry, starting with studies that demonstrated the benefit of using fine screens to produce consistent lower silica concentrates, followed by improvements in fine sizing equipment that have made effi cient screen classification in ball mill circuits practical. Case studies are used to demonstrate how positive sizing with screens can be used to significantly shift concentrate ‘grind/grade’ relationships.

Jul 11, 2011

The cloud transform simulation is a technique used to generate realisations of correlated attributes. The principle of this technique is to partition the scatter diagram between the input attributes into several interval classes and derive for each class a cumulative distribution function (CDF) using only the data pairs of the scatter diagram in that class. The simulation then proceeds like a traditional Monte Carlo simulation but using the derived CDF in each class.The cloud transform simulation has the advantage of being a simple and fast technique that is able to reproduce the uncertainty in the relationship between the two input attributes regardless of whether the relationship is linear or not. However, the technique has three major drawbacks. First, the number of classes has an impact on final simulated results and there is not a robust approach to define such number. Second, simulated results exhibit some saw tooth variations that are unrealistic and third the reproduction of the spatial continuity of the simulated attribute is not guaranteed.This paper presents the use of the quantile regression approach in order to overcome the first two disadvantages of the cloud transform simulation. Details of the technique and how it can be coupled with the cloud transform simulation are presented along with a real case study.

Sep 26, 2011

By C Buchanan

For a long time there has been a known relationship between the northern Heavy Mineral (HM) deposits of the Murray Basin to the extensive north east trending ridges in the area. These ridges have been a targeting tool for exploration and have uncovered some significant discoveries, some of which have turned into mining projects. Bemax’s Ginkgo and Snapper deposits are good examples of how the faulting helped create an economic deposit but also result in significant planning issues in the exploitation of these deposits. Material balance, induration and pyrite issues have been made easier to manage through good geological understanding of the deposits.

Aug 22, 2011

The tangible effects of leakage are presented graphically, and a technique for quantifying the leakage characteristics of a ventilation column using the æSolveÆ capabilities of a common spreadsheet is demonstrated. A case study of a working decline in Western Australia is used to demonstrate the potential for more realistic design of development ventilating systems, and for more cost effective management of the condition of the duct.

Jan 1, 2002

By Y Chung, B Choi, H Lee

Numerous studies have explored refractory corrosion in the presence of slag and/or metal, utilising the Finger Rotating Test (FRT). Recent experimental results revealed that corrosion initially increased with rising rotation velocity but was then suppressed above a critical rotating speed, under conditions involving a two-liquid solution of slag and molten steel. This phenomenon indicated that the liquid/liquid interface movement occurred during spindle rotor. However, understanding of the phenomenon, known as the rod climbing effect, remains inadequate in the case involving slag, molten steel and refractories. To gain deeper insights, a simulation experiment was conducted on the phenomenon using silicon oil/water and the phenomenon was analysed using computerised simulation software (Ansys Fluent). Experimental modelling demonstrated that interfacial movement occurs even at low rotation velocity, as low as 200 rev/min, when the viscosity of silicone oil is at 100 cP. Computational analysis utilising the Volume of Fluid (VOF) method and a realisable k-ε turbulence model elucidated that interface elevation during rotor rotation arises due to viscosity disparities between the two fluids. Furthermore, this movement is more pronounced when the viscosity difference is lower. Additionally, the study findings suggest that higher density differences between two liquids suppress the phenomenon of interface movement.

Jun 19, 2024

By H Kim, J Park, J Lee

Silico-ferrite of calcium and aluminium (SFCA) is a bonding phase in the iron ore sinter. The phase transition upon melting of SFCA was investigated with Differential Scanning Calorimetry and Confocal Laser Scanning Microscope. The initial melting of SFCA occurred at 1183.2°C and a massive melting was found at around 1351.1–1358.2°C. A phase transition-melting was investigated at 1476.5–1478.7°C. The liquid phase was composed of immiscible phases. The present results would be utilised to design a new iron ore sinter for better processing performance in a hydrogenenriched ironmaking process.

Jun 19, 2024

Dust emissions from mining, material processing and ship loading operations (fugitive dust sources) are an environmental issue of increasing concern to both government regulators and the community. The main concerns relate to potential amenity, health and environmental impacts from the emissions. Therefore it is imperative that mining/ processing operations, as part of their overall environmental management, reduce fugitive particulate emissions to as low a level as is practicably possible. This technical paper outlines the mechanisms that lead to fugitive particulate emissions, the importance of understanding the exact cause of fugitive emissions, monitoring methods that can be used to quantify the emissions from specific sources, the use of atmospheric dispersion modelling in dust management and innovative dust management strategies including predictive meteorology and proactive management.

Jan 1, 2009

By S J. Henderson

Pumped co-disposal of coal processing waste was promoted in the 1990-2000s as a low-cost highperformance alternative to tailings dams. In particular it would avoid high up-front capital for rejects trucks and dam embankments, and would produce a combined waste deposit with better geotechnical properties than either coarse rejects or tailings. Overall, the promise was not delivered; in particular, upon discharge the waste segregated by size, and operators responded by moving the coarser waste to contain the finer waste. In consequence, not only did design analysis lag behind construction, but some of the initial expectations persisted with the result that analyses did not fully represent what was occurring on the ground. After more than twenty years inspecting, designing and tending Co-Disposal Areas (CDAs), it is apparent that they are essentially upstream constructed tailings dams with some more favourable aspects but also a few unique quirks. Although waste management technology has moved on somewhat, the high cost of changing CHPP waste circuits means that most mines with pumped codisposal will continue to discharge mixed waste slurry into CDAs. It is therefore worthwhile to share some lessons in the hope of promoting sounder design, operation and rehabilitation. These include: • Discharged waste does not form a homogeneous wholly competent deposit but instead comprises materials ranging from sandy gravel to silty clay with the distribution determined by movement of the discharge and decant structures; • CDAs circulate and contain a lot of water; • As a result of the first two points, some areas of the CDA comprise saturated fine waste that is no different from tailings and, like tailings, often behaves in an undrained manner; • Seepage is inevitable and desirable because strength improves as water is removed. However, stability is strongly impacted by pore pressures and in design these need to be rationally rather than optimistically considered; • As CDAs are built to about 40m or higher, strength-deformation characteristics of the foundation become more important; • Even if geomechanically stable, CDAs will need covers to prevent salts and acids from reaching the surface; and • Erosional stability of the cover material(s) will probably dictate maximum slopes for rehabilitation.

Jul 1, 2021

By C A. Foss, K Leslie, C Arnold

Magnetic susceptibility measurements provide rapid, non-destructive testing of drill core, but cannot directly map magnetite and/or hematite content. Combined magnetic susceptibility and magnetisation measurements provide much more diagnostic information and, with sparse calibration constraints, are able to quantify magnetite and hematite concentrations and potentially map differences in grain size and texture. We have developed a travelling three-component vector magnetometer that can be run alongside core to map its external magnetic field. The logger has been designed to operate in core sheds and at remote drill sites. It is used to rapidly scan a length of core, with each core being scanned in different rotations. The magnetic field contributions from any remanent magnetisation rotates with the core and cause differences between successive measurements, while the field contributions from any induced magnetisations with isotropic magnetic susceptibility remain constant. Deconvolution of the magnetic field data with simultaneous three-channel inversions of the multirotation data separates remanent and induced components. Interpretation of this data provides estimates of the intensities of induced and remanent magnetisations, the orientation of the remanent magnetisations and the ratios of the induced and remanent magnetisation strengths. We expect these magnetisation parameters to correlate with stratigraphy through a banded-iron formation. Furthermore, we anticipate that we will be able to use this information to map zones of oxidation and other changes along the core. This novel instrument is one component of an integrated CSIRO program to provide new capabilities for iron ore exploration and development based on studies of magnetic fields and magnetisations at scales ranging from centimetres for these core investigations to tens of kilometres for formation studies.CITATION:Foss, C A, Leslie, K and Arnold, C, 2015. Rapid logging of different magnetic phases in banded ironstones using a travelling three-component vector magnetometer, in Proceedings Iron Ore 2015, pp 271–276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By H Zhai, C Zhang, I Canbulat, K Yui

Sedimentary rock is a lithology that is commonly encountered in mining practices. Their properties, especially the resistance against weathering, are often of critical importance to long-term engineering stability due to their ubiquitous existence on the earth’s crust. The weathering of rocks is a complex process that involves physical degradation, chemical and biological erosions. In this study, the impact of physical weathering on four common sedimentary rocks, namely sandstone, siltstone, limestone and shale, are simulated in the laboratoryoratory environment taking into consideration the impact of preservation condition, temperature and time. In order to optimise the design of the experiment, Taguchi’s design of experiment method is implemented based on the L16 orthogonal array and selected simulation conditions. The weight and dimension variation, fracture intensity, slake durability, and uniaxial strengths of specimens are then tested to quantify the impact of weathering under various conditions. The results indicate that weathering significantly influences the strength of shale, siltstone and limestone but not sandstone. The impact of weathering on dimension variation is insignificant. For soft rocks, most physical weathering took place after second cycle of simulation, resulting in strength reduction up to 100 per cent (disintegration) but generally in a range from 28 per cent to 32 per cent. Additionally, time is the most important factor contributing to the physical weathering of weak rocks, followed by residual, preservation conditions and temperature. Last but not least, some shales, depending on the content of clay minerals, tend to develop significant fracturing or even disintegrate under the influence of weathering.

Nov 29, 2022

By A Mackay

As a result of the explosion in the 512 panel at the Moura No 2 mine in 1994 the role of the ventilation officer (VO) to submit sealing plans (on behalf of the operator/underground mine manager) has become one of the key duties of the VO of an underground coal mine in Australia. The intent of a sealing plan is to document the controls used to manage the build up of flammable concentrations of gases, and for these controls to be reviewed by the industry regulators. These sealing plans have brought a large amount of focus onto the sealing process and served the industry well. The legislation does not define sealing, or when it begins, but throughout the industry typically sealing plans are submitted 30 days prior to the last seal being constructed. This practice appears to have originated from the Moura 512 panel being a standing bord and pillar panel and where the explosive gas mixture could only occur after it was sealed. However, since the Moura disaster the industry has become dominated by goafing style longwall mining. Goafing panels differ from standing bord and pillar panels in that they typically have an unventilated goaf that can potentially contain an explosive mixture from start-up. This was recently highlighted by the explosion and fire on Longwall No 1 Tailgate at the Blakefield South Mine in 2011. The author ponders whether the industry should revisit sealing plans to focus on the core hazard and define that sealing begins when flammable concentrations of gases are created. Although defining when mine sealing begins is the key outcome of this paper, the main point is that VOs and industry regulators need to clearly understand what can occur in the atmosphere of underground coal mines. CITATION:Mackay, A, 2013. A case for change - Defining mine sealing and understanding flammable mixtures during sealing, in Proceedings The Australian Mine Ventilation Conference , pp 307-310 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By J Cronin, R Burgess-Limerick, T Horberry, L Steiner

"Automation offers the mining industry great potential for improvements in productivity and safety. However, the experience of introducing automation in other industries has been that the full potential of new technology is not always realised. Designers are surprised, for example, to find that automation does not eliminate human errors. Unwanted and unexpected consequences also arise if the introduction of automation fails to consider how people will adapt to the new technology. A focus on the technical aspects of automation is necessary but not sufficient for success. The potential for improvements in productivity and safety promised by automation will only be achieved if the joint cognitive system that emerges from the combination of humans and automation is designed to perform the functions required for system success. This case study describes the human factors issues associated with the introduction of automation generally, and describes a case study of the successful implementation of loader automation at Northparkes mine.Information obtained through a site visit and interviews with operators, safety staff and the project manager revealed the following strategies for successful design and implementation of the automation system: involve the people who will be impacted encourage constant communication between operators and designers provide operators with essential information avoid providing non-essential information provide the operators with flexibility empower operators to take action take advantage of the new possibilities automation provides.CITATION:Burgess-Limerick, R, Horberry, T, Steiner, L and Cronin, J, 2017. Mining automation human-systems integration – CMOC-Northparkes case study, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 93–98 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 16, 2017

By T B. T Nguyen, L Matthews, D O’Dea, T Honeyands, T Harvey

Productivity and fuel consumption of the blast furnace is driven by the quality of the iron ore sinter, which in turn is related to the sinter mineralogy. The sintering conditions including temperature and gas composition have a significant influence on the formation of melt and finally the mineralogy of the sinter. In this work, analogue sinter tablets were produced from iron ore fines in a laboratory furnace with tightly controlled temperature profile and oxygen partial pressure in the gas. The mineralogy of the sinters was analysed using reflected light microscopy. The results showed that increasing thermal enclosed area (area enclosed by heating and cooling curve above a reference temperature) reduces primary hematite and platy silico-ferrite of calcium and aluminium (SFCA) contents. This is attributed to increasing melt formation, leading to greater assimilation of the iron ore particles. Lower magnetite was found for tablets with greater median pore size, which is thought to be due to greater oxidation of magnetite to hematite during cooling in air. It was also found that higher alumina content was found to result in more SFCA formation under the same heating/cooling conditions, whereas tablets with higher goethite had higher assimilation and produced more secondary hematite on cooling. Finally, it is necessary to relate the enclosed area to the temperature at which the melt formation becomes significant which strongly depends on chemical composition of the ore studied.

Nov 8, 2021

By T D. H McGrath, R Byleveld, W P. Staunton, J J. Eksteen

"The Gold Technology Group at Curtin University through the AMIRA P420 series of projects has recently developed the integrated liberation leach model (ILLM) for optimisation of gold plants. The model encompasses recovery by both gravity (batch centrifugal concentrators or BCCs) and leach adsorption (CIP/CIL) circuits. The ILLM essentially combines the Group’s well-known standalone models (ie gravity and SIMCIL) to create a robust simulation package.The ILLM process model provides a tool for sites to determine optimum set points for operations to optimise recovery (eg target grind size). It can also be used to predict the effect on gravity recovery, leach recovery and overall recovery when changes are made to circuit design, either temporarily (eg a leach tank taken off-line for maintenance) or as part of a circuit expansion (eg expanded gravity circuit capacity, or addition of leach tank capacity).This paper discusses the capability of the ILLM process model by highlighting a recent case study. The paper also addresses the test work and plant data required as model inputs, as well as limitations and the application of the ILLM to greenfield projects.Citation:McGrath, T D H, Staunton, W P, Eksteen, J J and Byleveld, R, 2016. Application of an Integrated Liberation Leach Model for Process Optimisation, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 173–178 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By J Webb

"It is vitally important in projects where the cut-off grade is low that there is no contamination during the sampling and sample preparation process, both in the ore and the waste zones. Failure to identify contamination could have devastating financial consequences for a project. The use of a variety of blank types is essential for ensuring that contamination is identified and eliminated at every stage of the sampling and sample preparation process. This paper examines an instance where an effective assay quality assurance and quality control (QA/QC) program was able to identify and eliminate a source of significant multi-element contamination in the prefeasibility stages of an open pit project. This examination includes the: evidence for contamination findings of the investigation process of resolving the problem and correcting the data evidence for both addition of metal and dilution through contamination potential impact on the project had this issue not been dealt with. It was through the use of a combination of blank types that the QA/QC process at Mount Isa Mines (MIM) identified a contamination issue at the first crushing phase of sample preparation. Identification of the contamination allowed MIM to stop assaying activities and work with the laboratory to correct the problem. The sampling program could then be continued with no further doubts about the sample preparation process. Contaminated samples were resampled from retained core. With the continuous monitoring provided by the blanks program, it was possible to ensure that only clean results went into the resource modelling data set. CITATION:Webb, J, 2014. When nothing is what you need – the importance of using blanks at all stages of sample preparation, in Proceedings Sampling 2014 , pp 49–54 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 29, 2014

By G D. McDonald

Flinders Mines is an ASX300 iron ore explorer and developer with a tenement package located in the Hamersley Ranges region of Western Australia, approximately 70 km north of Tom Price. Exploration over the past three years has identified a Global Resource in excess of 740 Mt at a grade of 55.4 per cent Fe (+50 per cent Fe cut-off). This resource is spread across multiple deposits and has been divided into a number of mineralisation type domains based on geometallurgical and geochemical boundaries. These domains are comprised of transported haematite rich detrital iron deposits (DID) and goethite dominant Channel iron deposits (CID) as well as in situ bedded Brockman iron deposits (BID). On the basis of differences in physical and chemical characteristics, the DID have been divided into four discrete units. The four DID units form a stratigraphic sequence with the iron grade increasing and the contaminant concentrations decreasing with depth. The upper DID unit is lower grade and currently unlikely to provide a marketable product, without signifi cant beneficiation. The lower three DID units, together with the CID and BID, are of a higher quality and have the potential to yield marketable ore. The ability to define and recognise these different units has resulted in a more reliable and robust geological interpretation and hence greater confidence in the resulting resource model. This has been evident in the excellent conversion of inferred to indicated resources.

Jul 11, 2011

By M Yahyaei, F Reyes, R Lage, V Jokovic

Equipment wear is strongly related to the performance of grinding circuits. In particular, SAG mills are subjected to the wear of their shell liners and grates. Changes in lifter height and face angle impact mill performance, while classification at the mill discharge is also affected as grates wear out. Moreover, liner mass loss caused by wear affects how operators interpret readings of sensors such as load cells or bearings pressure. Automating and optimising grinding circuits under these constrain becomes challenging due to the nonlinear and dynamic nature of the system. The operation of SAG mill grinding circuits remains largely dependent on human intervention, which frequently results in inconsistencies in performance across shifts, reflecting the operator’s personal preferences, experience, and other human factors. The influence of human factors can be reduced by careful training of operators as well as by automation using advanced supervisory control. The latter approaches could benefit from the development of dynamic process models that consider the effects of wear on the performance of equipment over time. This paper presents detailed industrial data showing the effects of wear on SAG mill performance. Additionally, a dynamic SAG mill model that accounts for these phenomena is proposed and demonstrated in a simulated environment. This model is shown to mimic the effect of wear on the performance of industrial scale mills and the operational constraints they are subject to, thus extending traditional SAG mill models. Incorporating wear into modelling and simulation platforms can improve the understanding of the effects that wear can have on the performance of key assets in comminution circuits and may allow the development of more robust model-based advanced process control strategies.

Aug 24, 2022

By V Gau, L Overmeyer, M Kesting

Economically efficient mining processes can be significantly assisted by the implementation of sensor technologies for the detection of materials and boundary layers between materials inside the stratum. These sensors are meant to facilitate the machinery operator and illustrate furthermore the prerequisites in assisting tools towards fully automated mining equipment. Therefore, project æSensory Identification of Material Type and Detection of the InterfacesÆ (SIMT) aims at the integration of ground penetrating radar (GPR) and geoelectric sensor technology by endowing with them a bucket of a bucket wheel excavator. For this reason, a sensor bucket was developed and tested in the Inden Mine of RWE Power AG. The feasibility of integration and deployment of such sensor technology has been proven effective for the conditions of open cast mining. The main focus of current research lies on developing algorithms to analyse the acquired measurement data from the sensors to automatically detect layers and materials. A computer network receives the GPR and geoelectric measurement data as well as the positioning data of the sensor bucket. The positioning data mainly consists of GPS and encoder information, which is merged with the sensor data by using the UTC time stamp. With the aid of consecutive processes the relevant information will be extracted and provided to the user. The aim of SIMT is to replace material identification, traditionally carried out by the operator, by implementing a continuous operating interpretation system in mining equipment based on GPR and geoelectric sensor technology, resulting in more detailed information regarding the working face during an excavation. This detailed information provides an opportunity for efficient planning and controlling of selective mining of natural deposits, such as the process of lignite mining.

Sep 26, 2011

By D Connelly

The Iron Road Limited Central Eyre Iron Project (CEIP) area, located on the Eyre Peninsula of South Australia, covers extensive Archaean iron formations that occur as coarse-grained magnetite bearing gneiss. The cumulative strike length, estimated from aeromagnetic data, is at least 95 km.The project is located in a grain growing area 185 km west of the existing iron ore and steel making operations of OneSteel at Whyalla. A narrow gauge railway built to transport agricultural products to the deep-water port of Port Lincoln, 175 km to the south, traverses the project area. A number of well-serviced rural townships are located nearby. Current activities include resource expansion drilling, extensive metallurgical test work, community consultation and a Prefeasibility Study (PFS) that commenced in April 2010.The PFS has encompassed the Central Eyre Iron Project, comprising the three significant iron occurrences (Warramboo, Kopi and Hambidge) and was completed in early 2011. Extensive test work programs and metallurgical modelling confirmed viable process options for the project, using simple off the shelf processing technology.Preconcentration by coarse cobbing yielded promising results, and is the key to reducing not only the capital expenditure but also the operating cost, in particular the power cost, which is the highest operating cost component of a magnetite benefi ciation plant. The ore is also amendable to high pressure grinding rolls (HPGR) processing. This offers a potential for further reduction of the energy requirements.Test work also confirmed that a high grade blast furnace quality concentrate (~68 per cent Fe) can be produced at a relatively coarse grind (P80 106 µm).

Jul 11, 2011