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By T Gill, A Faragher, B Scott, V Kakebeeke

In 2000, after six year intensive exploration for high-grade haematite deposits, Rio Tinto included the channel iron deposits (CID) as a specific iron ore target in the Hamersley Province iron ore exploration program. The exploration model was simple and based on the then current understanding of CID genesis. Fundamental to the model was an interpretation that CID deposits after their final accumulation stage could be entirely concealed in their channels. Inversion to mesas and therefore exposure of the CID profile would only occur in areas where the modern drainages follow the ancient and have significantly incised their current bedrock. The model took encouragement from observations at Bungaroo Creek, where large CID accumulations occur in a deep valley incised in the Wittenoom Formation concealed below recent valley fills derived from the surrounding BIFs. Also, in the headwaters of the Yandicoogina system CID occurs below a more recent cover of calcrete and clay. After a number of failed or partially successful attempts, exploratory drilling in 2002 in the Caliwingina valley in the northern Hamersley Range identified significant CID mineralisation. Subsequent drilling programs from 2003 onwards revealed the presence of a large CID system, which stretches from the middle reaches of the Caliwingina Creek to deep under the sediments of the Fortescue Valley, a channel length of more than 30 km. Although the drilling is still somewhat sparse, the geological resource estimation suggests that Caliwingina is presently the third biggest CID system of the Pilbara (after Yandicoogina and Bungaroo Creek) and is of comparable size to the premining Robe River system (1.6 Bt), with comparable Fe-grades to the Yandicoogina global resource grade (57.7 per cent Fe). Large detrital and canga deposits overlie the Caliwingina CID, or interfinger with it, and although the economics of these are presently unfavorable, could ultimately present a low-grade iron resource of slightly smaller size to the CID mineralisation at Caliwingina Creek. Together with the recently discovered Serenity and Solomon deposits, as well as Cabbage Gum Bore and other smaller occurrences, the Caliwingina Creek deposit is part of a major new CID district in the central Hamersley Ranges, approximately halfway between Yandicoogina and Robe River. Although exploration in this new district is still underway, the preliminary indications are that this area will provide a total CID resource well over 3 Bt, and is on a par with the major known CID systems in the Hamersley Province.

Jan 1, 2009

By E Jak, M Shevchenko, E Nekhoroshev, D Shishin

In the field of pyrometallurgy, the presence of multiple molten phases with distinct chemical compositions, such as slags, mattes, speiss liquids, metals and molten salts, is a well-known phenomenon. These phases exhibit strongly non-ideal solution behaviour and are mutually miscible to varying degrees. To describe these complex molten liquids, the Modified Quasichemical Model (MQM) has proven effective and has been applied to numerous binary, ternary and several higher-order multicomponent systems related to pyrometallurgy. In recent decades, the complexity of high-temperature processes has escalated due to increased impurity concentrations in primary ores, the incorporation of recycled consumer products and the integration of metallurgical plants through by-product and waste exchanges. To address these issues, PYROSEARCH laboratory has been developing large 20-component thermodynamic database using a generalised CALPHAD (CALculation of PHAse Diagrams) methodology integrated with experimental investigations. Over the past decade, strategic decisions were made balancing the ability to generate experimental data, prediction power, accuracy, stability of calculations, as well as computational time, which are discussed in the paper. Examples provided for issues of >3 liquid immiscibility, non-ionic behaviour and exaggerated ‘sharp’ enthalpies of mixing in silicate slags, dealing with multiple oxidation states, as well as comparative analysis of pair and quadruplet approximation in MQM.

Aug 21, 2024

By R Symes

The Fosterville Goldmine in Victoria Australia employs the BIOX« Process to liberate gold from its sulfidic flotation concentrate through bacterial oxidation. Gold occurrence is primarily as submicron particles in pyrite and arsenopyrite and has been described as being in æsolid solutionÆ and therefore not amenable to direct cyanidation. Once liberated by the oxidation process, the gold is then available for cyanide leaching. During the oxidation process it has been found that a portion of the liberated gold becomes suspended in the liquid phase in what appears to be a colloidal state. This liquid becomes a waste stream during washing of the oxidised solids and the suspended gold is therefore lost. A method was previously developed using an addition of quebracho tannin to significantly reduce this loss by formation of an iron-tannin precipitate which captures the gold which then reports to the cyanide leach circuit with the oxidised concentrate solids onto which it is adsorbed.This paper discusses the development and plant trial of a second processing step to further enhance gold recovery by use of flotation tailings essentially as a source of extra surface area to capture residual tannin-iron precipitate and its associated gold not recovered in the first step.CITATION:Symes, R, 2012. Recovery of colloidal gold from oxidised concentrate wash liquor - Further improvement, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 383-388 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By B Prasad, M P. Roy, P K. Singh, C Drebenstedt

Blasting operations play a pivotal role in the overall economics of opencast mines. The blasting subsystem affects all the other associated subsystems, ie loading, transport, crushing and milling operations. Fragmentation control through effective blast design and its effect on productivity is a challenging job for the practicing blasting engineer due to inadequate knowledge of actual explosive energy released in the borehole, effect of varying initiation practice in blast design and its effect on explosive energy release characteristic. This paper describes the result of a systematic study on the impact of blast design parameters on rock fragmentation at two mines in India. Both the mines use draglines and shovel-dumper combination for removal of overburden. Despite its pivotal role in controlling the overall economics of a mining operation, the expected blasting performance is often judged almost exclusively on the basis of poorly defined parameters such as powder factor and is often qualitative, which results in a very subjective assessment of blasting performance. Such an approach is a very poor substitute for accurate assessment of explosive and blasting performance. Forty-seven blasts were conducted with varying blast designs and charging patterns and their impact on the rock fragmentation are documented. A high-speed camera was deployed to record the detonation sequences of the blasts. The efficiency of the loading machines was also correlated with the mean fragment size obtained from the fragmentation analyses.CITATION:Singh, P K, Roy, M P, Drebenstedt, C and Prasad, B, 2015. Blast design parameters and their impact on rock fragmentation, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 755–762 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

I was delighted to be invited to be patron of this Joint Conference, but the challenging task you have set yourselves, and your speakers' depth of expertise, deny anyone, even the patron, the opportunity to be patronizing. Australia's history has been inextricably link- ed with the fortunes of our great mining industry. That link will remain. Just as the gold rushes of the last century, and the discoveries at Kalgoorlie and Broken Hill changed the lives of generations, so the more recent development activity in iron ore, bauxite, nickel, coal, and uranium are having a significant impact on the lives of Australians today. The minerals industry has contributed to Aust- ralia's jobs and prosperity. Mining is not free of problems, but so long as safeguards are strong and appropriate the net benefits the mining in- dustry brings Australia will continue to be enor- mous. We rely on our mining industry to find, prove, develop and sell our minerals profitably, and my Government is committed to maintaining a healthy mining industry.

Jan 1, 1978

By A S. Derrington

High-accuracy, solid-state digital reference barometers have proven to be well suited to conducting underground barometric pressure surveys. The only problem is their expense; at least A$4000 each. For this reason, and because barometric pressure surveys are not a routine undertaking, very few mines have been able to justify the purchase of suitable instruments. The author knows of only three Australian metalliferous mines that own them.However, this may soon change given the recent development of low-cost, mass-produced miniature barometric pressure transducers. These transducers were developed to provide an altimeter function in the latest generation of smartphones. The main purpose of the inbuilt altimeter function is to allow the smartphone to be aware of its altitude when the global positioning system satellite signal is lost.This paper describes a prototype barometer that was constructed using one of the most accurate of the latest generation of piezo-resistive smartphone barometric pressure transducers. The prototype instrument was constructed for less than five per cent of the cost of a commercially available digital reference barometer. The prototype was subsequently tested against a reference barometer at the University of Queensland’s Experimental Mine to verify its accuracy and suitability for measuring pressure differences between underground survey stations.It is expected that the instrument’s low cost will pave the way for barometric pressure surveys to become more commonly used in mines. In turn, the resulting improvement in knowledge of major underground pressure losses should allow mine ventilation officers and engineers to optimise their ventilation systems and potentially reduce overall operating costs.An alternative option would be to use a barometer-equipped smartphone as a survey instrument, provided that its inbuilt barometer module is sufficiently accurate.CITATION:Derrington, A S, 2015. Development of a low-cost instrument for barometric pressure surveys, in Proceedings The Australian Mine Ventilation Conference, pp 331–336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By I Canbulat, A Mcquillan

This paper presents a parametric analysis showing the impact of virgin in situ stresses on a shallow (less than 100 to 150 m) high slope in a jointed sedimentary rock environment. Slope stability is assessed at varying ratios of slope orientation and horizontal stresses. The results of this study indicate stress conditions should be included in stability assessments of excavated slopes, particularly where structure is orientated perpendicular to the direction of horizontal stress. Some consideration of stress state is applied in deep open cut pits (eg those with planned excavations of 400–1200 m) (Myrvang et al, 1993; Stacey et al, 2003; de Bruyn et al, 2014; Kozyrev et al, 2015). Dodd and Anderson (1972), Kalkani and Piteau (1976), Lee (1978), Coulthard et al (1992), Noorani et al (2011) have studied the effect or horizontal stress and its impact on slope stability, showing that tensile stresses tend to develop at the crest of the slope, with larger tensile zones for higher horizonal stresses and steeper slope angles (Stacey, 1970, 1973; Sjoberg, 2013). However, the consideration of virgin stresses on shallow slope stability is less frequent (Lynch et al, 2005; Dight, 2006; Lucas, 2006; Sjoberg, 2013). This has led many geotechnical engineers to believe the impact of virgin in situ stresses on open cut slope stability is minimal and not worth time or consideration in modelling, or their effects on slope stability are still poorly understood (Stacey et al, 2003; Sjoberg, 2013).

Nov 29, 2022

By T Niitti, J Turunen, P B, A Rinne

In todayÆs marketplace, with high metals prices, many operations are faced with the challenge of improving recovery in the particle size ranges which are normally difficult to recover. This presentation focuses on the various methods used to alter the flow dynamics in a mechanical flotation cell, thereby improving metallurgical results. Modern computational fluid dynamics (CFD) tools have been used in the design phase, with subsequent validation at the plant. Some of the validated variables include mixing profile, power draw and local air hold-up. This presentation underlines how modern CFD analysis can be used to screen and select different approaches before commencing costly trial-and-error experiments at plant scale. Two methods of affecting flow dynamics are discussed û firstly, by altering the geometry of the rotor-stator area and, secondly, by fitting additional features in the tank. The rotor-stator area can be modified to provide more concentrated turbulent kinetic energy or, respectively, to provide more pumping efficiency with less attrition. The tank can be fitted with various additional features, aimed to create different particle suspension profiles. The benefit of both methods is that they can be applied not only to newly installed flotation technology, but also to existing plant cells, thus enabling potential improvement in the mixing profiles, solids suspension, tank sanding and metallurgical performance. Results of several sitesÆ tests are discussed in terms of flow variables measurement as well as metallurgy. This paper demonstrates the effects of different flow dynamics on the mixing profiles and metallurgical results of existing mechanical flotation cells.

Jan 1, 2006

By D Gagnon, P Bouchard, F Vanier, E Soares de Lima Filho, J El-Haddad, M Sabsabi, G J. Wilkie, A Beauchesne, A Hamel, A Blouin, T Vaillancourt, F Boismenu, A Harhira, A Plugatyr, C Padioleau

Quantitative mineralogy is an established discipline in the geosciences and is aimed at providing mineral grade and texture information for geological and mineral processing applications. The two core technologies underpinning Quantitative Mineralogical Analysis (QMA) are Scanning Electron Microscopy (SEM) in combination with Energy-dispersive X-ray Spectroscopy (EDS). Technologies such as QEMSCAN and MLA are now routinely used to optimise the performance of large-scale mineral processing plants in the base and precious metal sectors. One of the major disadvantages of the QMA methods used today is extensive sample preparation requirements which make application of this technique to real-time mineralogical characterization not feasible. A breakthrough has been achieved by the National Research Council Canada in collaboration with CRC ORE by developing a novel Laser Induced Breakdown Spectroscopy (LIBS) based technology capable of real-time mineralogical characterization of process streams without sample preparation. The potential applications of this technology include, but not limited to, in-pit muck piles, underground draw points, cross-belt analysis as well as slurries. This paper describes the development of the LIBS-based technology from a proof-of-concept (TRL2) to the construction of a prototype sensor and its validation in a simulated environment (TRL5). Future work is being planned to test and further validate the LIBS sensor on a mine-site which will progress the technology to its next readiness level (TRL6).

Nov 10, 2020

By Huleatt M, Perkin D, McLeod I, Mock C, Pratt R, Gourlay A, Timoney E, Knight N, Ward J

Generally speaking, Australia's reserves of its more important minerals (in terms of export earnings) are adequate to sustain forecast rates of production to the year 2000. The rate of forecast production increases of these commodities (aluminium - whether as bauxite, alumina or metal, black coal, iron ore and ferro-alloy minerals, base metals, tin, uranium, and mineral sands) reflects a well- ordered and sustained growth phase of Australia's mineral industry.

Jan 1, 1981

By P Fuller, A R. Penney

Re-commencement of mining in the Western Zone of Beaconsfield Gold Mine following a seismically-induced rockfall fatality in April 2006 required a change of mining method involving drilling and blasting from specially developed drives in the footwall of the orebody. Broken ore is mucked remotely from ore drives on each level. Support in the footwall drives is required to maintain stability during their development and as stopes are retreated, which increases induced stresses and further seismic events are triggered. The paper outlines the challenges involved and methods used to select the footwall drive support to handle both static and dynamic load demand. The importance of load development in the support system, its displacement capacity, the compatibility of support elements and energy absorption capacity of the support system are highlighted. It is usual in any support selection process to ensure that capacity exceeds demand to create a factor of safety. In this case the demands on the system relate to load, displacement and energy absorption and the support system capacity for each must ensure that appropriate factors of safety for each are achieved. The paper shows how these factors are not independent and that selecting a high factor of safety for load can lead to compatibility problems with support elements in the support system.

Jan 1, 2008

By T Purvis, J Calverd, A-K Greve

The Ernest Henry Mining (EHM) underground mine is situated adjacent to the Great Artesian Basin in North Queensland and within a fracture zone. Underground development commenced in February 2008 and has extended to approximately 1000 vertical metres below the surface.Groundwater has been encountered in numerous locations throughout the mine, predominantly on the eastern side of the orebody and often related to fault structures. Most of the groundwater encountered has been managed with conventional pumping systems; however, on occasions large water inflows have been encountered, which have had a significant impact on the planned development of the mine. Some of the intersections encountered had the potential to compromise the mine from a combination of high temperature (over 45°C), high pressure (3500 kPa) and high flows (50–100 L/s).This paper describes three case studies where significant water inflows were encountered and then controlled by the injection of cementitious grout into the rock mass. The case studies are the 1650 mid-shaft heading, the 1325 shaft access decline and the 1625 to 1475 fresh air rise (FAR) raise bore. Each case study includes a brief description of the event that occurred and the grouting equipment and techniques developed to enable mining to continue.The paper also describes the development of a hydrogeological map of the mine, the probe-hole regime used for high-risk headings and the required processes and systems to inject both cementitious grouts and polyurethane resin into the rock mass.CITATION:Purvis, T, Calverd, J and Greve, A-K, 2014. Management of high-pressure groundwater in underground development at Ernest Henry Mine, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 217–226 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By S Robinson, R Perkins, D Barrett, D Kepert, C Fowers

The discovery and delineation of significant mineralisation in the Eliwana region continues Fortescue Metals Group’s strong exploration success. In the decade after the first hole was drilled into Christmas Creek in mid-2004 a total of over 11 Bt of hematite-goethite mineralisation have been delineated supporting the raising of $13 B, construction of five mines, 620 km of rail and a five-berth port. As of June 2014, Fortescue was shipping at the rate of 155 Mt/a. The area including the Eliwana and Flying Fish deposits is one of a number of future growth opportunities that Fortescue is currently evaluating.The Eliwana and Flying Fish deposits occur on the south dipping limb of the Brockman Syncline/Jeerinah Anticline. The Eliwana group of deposits are hosted by the Brockman Iron Formation with the Flying Fish/Broadway group hosted by the Marra Mamba Iron Formation.Structurally the area is dominated by moderate southerly dips of the regional dome and keel style folding. The regional limb is locally cross-cut at a small angle by asymmetric north facing Ophthalmian folds trending 110°. These fold sets, in part, preferentially host subsequent supergene mineralisation. Faulting is only locally apparent.Early phases of exploration commenced in 2006, with mapping of Flying Fish and reconnaissance drilling in 2007. However, due to the concurrent discovery (Clarke et al, 2009) and subsequent fast tracked development of Solomon channel iron deposit and Firetail bedded iron deposit (Simpson et al, 2011) priority was placed on developing Solomon due to its relative proximity to existing Fortescue infrastructure. Staged follow-up drilling of both Marra Mamba and Brockman targets at Eliwana was progressively undertaken from 2008 onward.As of 20 May 2014 a total of 1494 reverse circulation (RC) holes for 54 248 m and 13 diamond holes had been completed, resulting in the delineation of a Mineral Resource of 740 Mt. Exploration via mapping, drilling and metallurgical evaluation of adjacent prospects continues with additional resources expected in the future.CITATION:Barrett, D, Perkins, R, Kepert, D, Robinson, S and Fowers, C, 2015. Geological setting of Eliwana and Flying Fish deposits along the north limb of the Brockman Syncline, Hamersley Province, Western Australia, in Proceedings Iron Ore 2015, pp 219–228 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By A Jankovic, D David, P Payne

Although the majority of current steel production is supported by iron ore sourced from high-grade haematite deposits, the long-term growing demand for steel has led to higher raw material prices and opened the way for many new magnetite deposits to also be developed. There is a rich and long history of magnetite ore processing in Western countries, including large operations such as Cleveland Cliffs in the USA and LKAB in Sweden, as well as smaller operations like Savage River in Tasmania. The challenge for virtually all magnetite operations is to minimise operating costs, which is dominated by the cost of power required to fine grind the ore in order to achieve acceptable concentrate iron grade together with low impurity content. This remains the case today and will be even more important in the future when a carbon tax is expected to become a significant addition to the operating costs for magnetite deposits. Historically, the lowest operating cost was achieved by multistage fully autogenous grinding with integrated magnetic separation steps between the stages. The major benefit of fully autogenous grinding is the elimination of steel grinding media costs and the need to discriminate between steel and magnetite in coarse magnetic separation. The separation step between grinding stages progressively reduces the amount of material to be ground. Application of more efficient grinding technologies developed in the last 20 years, including high pressure grinding rolls (HPGR) for fine crushing and stirred milling for fine grinding, has provided opportunities to further reduce the operating costs associated with comminution. Both technologies are already implemented in some magnetite processing operations, although in limited capacity. The results of a theoretical option study for high capacity processing of a hard, fine-grained silica-rich magnetite ore is presented in this paper, with the emphasis on comminution circuit options. Several circuit options are ranked based on a net present value analysis incorporating an estimate of carbon tax added in the operating cost. The study demonstrates the significant advantages of applying more efficient autogenous grinding technologies.

Jan 1, 2009

By B Wu, B W. Lei, B J. Duan

When a coalmine fire occurs, it is crucial to judge the developing trends inside the fire area by analysing the changes of gas concentration in order to formulate the proper rescue measures. At present, few researchers have focused on the relationship between the changing trend of gas product and basic characteristics of fire in the coal fire extinguishing process. To study the relationship of basic characteristics of coalmine fire during the extinguishing process, an experimental platform for coal combustion in a confined space was built, and gas production, flame image and coal temperature during the extinguishing process were monitored and analysed by an online continuous gas analysis instrument, camera and thermocouple. Research shows that during the burning phase of the coal sample in the confined space, the flame zone decreases gradually due to insufficient gas supply. The size of the flame zone fluctuates and shares a positive correlation with CO concentration, while sharing a negative correlation with O2 and CO2 concentrations. Then, in the extinguishing phase, the increasing rate of CO2 concentration and the decreasing rate of O2 concentration both decrease gradually, but CO concentration would rise for a period before it eventually decreases. Coal temperature continues to rise in the open flame stage and does not go down until the flame is extinguished.CITATION:Lei, B W, Wu, B and Duan, B J, 2015. Experimental study on extinguishing characteristics of coal fire in confined space, in Proceedings The Australian Mine Ventilation Conference, pp 279–284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

Development of a global failure criterion for rocks has been a desired goal in rock mechanics. Due to variations in factors affecting rock specifications and their mechanical properties, proposing a single failure criterion suitable for all rock types has proven to be unachievable. The theoretical failure criteria do not fit the real data correctly. Amongst empirical criteria, the Bieniawski criterion has demonstrated an acceptable agreement with laboratory generated data. It has been experienced that the ability to estimate rock strength via the modified form of this criterion is significantly improved. Based on the modified Bieniawski criterion and using VB.net, an associated Microsoft Windows program named 'RAMOCE' has been developed. The inputs of RAMOCE can be triaxial compressive strength data, Bieniawski parameters of a specific rock or the type of given rock. Based on input data, potential outputs of the program are Bieniawski's rock parameters, sensitivity analysis of the effective parameters, rock failure prediction and defining the type of given rock.

Nov 25, 2010

By G M. Zhomin, A S. Arkhipin, A Kondratiev

Viscosity of multicomponent slags is one of the crucial physicochemical properties for many industrial processes and technologies. While the viscosity-temperature relationship of completely molten slags can well be described by an Arrhenian-type law, the compositional dependence of viscosity is still not fully understood, especially in compositional regions with the lack of experimental data (eg at the glass-former concentration of 90 molar per cent or higher). In the present work major compositional relationships of the activation energy of viscous flow have been revised for numerous binary and ternary slag systems on the basis of experimental data collected and stored in the viscosity database OxiVis. For example, it has been found that the activation energy relevant to the polymerisation effect in binary systems of the MO-GFO type, where MO is the modifier oxide (ie monovalent K2O, Na2O, Li2O and bivalent CaO, MgO, BaO, MnO, PbO etc) and GFO is the glass-forming oxide (SiO2 or B2O3) is not always proportional to the third power of XGFO (contrary to the Urbain formalism) and can vary significantly dependent on the slag system. Also, the activation energy of the charge compensation effect has been revised for ternary systems of the AO-MO-GFO and AO-MO type, where AO is the amphoteric oxide (Al2O3, Fe2O3 or other). A simple polynomial model has been proposed on the basis of the carried-out analysis for estimation of viscosities of multicomponent slag systems. The model has been optimised against the experimental viscosities in the selected binary, ternary, and higher-order oxide systems and has been shown reasonable agreement with the experimental data.

Aug 21, 2024

By D Cliff, B Belle

Trigger action response plans (TARPs) are inherent to managing multiple hazards such as high gas content with multiple coal seams, high spontaneous combustion propensity, heat and ventilation. TARPs aim to provide assurance and guidance when the situation deviates from the original plan or there is a change in conditions that could be hazardous. Over the years, learnings from various incidents have continuously required coal operations to revisit the TARP trigger values that were based on historical data or guidance values from the industry. In most cases, the background to the basis of TARP statistical data (ie average, maximum, hourly or daily for the monitoring or sampling location) is unknown. The introduction of real-time monitoring devices to monitor gases and airflows has provided greater understanding of the hazard scenarios and their controls. This paper analyses the carbon monoxide data from operating longwall mines and compares these with the historical trigger values to understand the changes and identify improvement opportunities while setting trigger levels in the TARPs. As an example of setting trigger values, those used during the sealing of a panel are explored in terms of setting values based upon the sampling location and the level of risk. It is envisaged that the learnings shared herein will further enhance the understanding and management of multiple hazards in Australian coalmines.CITATION:Belle, B and Cliff, D, 2015. Improved trigger action response plan development based upon mine-specific data, in Proceedings The Australian Mine Ventilation Conference, pp 73–78 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

An enhanced gravity concentrator was installed in conjunction with an intensive leach reactor at the Sadiola plant in Mali last year and commissioned in December 2007. There has been much debate over the years as to the effect of gravity concentration on overall plant performance. The late Dr Laplante suggested that for every ten per cent of gold recovered by gravity, there was a corresponding 0.1 per cent to one per cent additional overall plant recovery. The results at Sadiola are consistent with this hypothesis with an overall four per cent gain in plant recovery. With total gold recovery of 12 per cent in the gravity section, grades are increased from 3.54 g/t in the gravity feed to an average of 2 600 g/t in the concentrator feed to the inline reactor. The recovery of gold in the inline reactor is in excess of 98.5 per cent. This paper discusses the background to the project, the laboratory test work prior to the equipment selection, the operational results of the system, as well as the benefi ts of the future application of high mass yield centrifugal concentrators in base metals, sulfides and industrial minerals. Bench scale, pilot scale and plant practice examples are also presented.

Aug 1, 2010

By G Caddy, M Middleton, S Kerec, R Keil, J Tsalapatis

Arrium’s OneSteel Whyalla Steelworks in South Australia is a fully integrated plant which operates a single blast furnace. The key operational objective has been to maintain high process availability and stability while maximising the process efficiency and the produced hot metal quality. All ferrous raw material input feeds are sourced exclusively from company iron ore deposits in the nearby Middleback Ranges. The Whyalla blast furnace has mostly operated using a combination of a high percentage of pellet feed, produced in Whyalla, together with screened lump ore.The unique ironmaking challenge has always been to extract the maximum value from the ferrous burden feed available locally. In earlier times, high-grade hematite lump ore was available for both screened lump ore and pellet production. Blast furnace trials from acid to fluxed pellet feed commenced in 1977. The furnace pellet feed has been wholly fluxed since 1981. Many pellet/lump ore feed mixes and significant pellet chemistry composition design changes have been made over the years. These changes have been aimed at best balancing the ferrous burden availability/cost and the optimum reducibility/high temperature melting behaviour of the charged ferrous feed within the blast furnace. In more recent times since 2007, the Whyalla blast furnace operation has transitioned from a hematite based pellet feed to a magnetite based pellet feed while there is an ongoing contest dealing with diminishing absolute quality/increased variability raw material feed inputs.The paper will detail key elements of the Whyalla blast furnace operational philosophy with regards to ferrous feed use and process optimisation. The blast furnace ferrous feed design considerations will be discussed, together with the test work performed, the operational and slag design transition strategies employed and the process results achieved.CITATION:Tsalapatis, J, Middleton, M, Keil, R, Kerec, S and Caddy, G, 2015. The use and optimisation of ferrous feed at the Whyalla Blast Furnace, in Proceedings Iron Ore 2015, pp 377–384 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015