Search Documents

By C Parihar, R Garg, A Bhandari, S Bhandari

Blasting can impact the efficiency of entire downstream mining operation. Individual technology solutions for blasting have been available in the industry for many years but all of them only cater for certain aspects of blasting. Many of them are based on individual research and/or experiences. Some of the available software solutions are not suitable to be used in the field as that they need advanced skills or tools. Also, most do not take technology advancements like mobility, advanced data analytics, web solutions and integration into consideration. Hence, no technology platform is currently present in the industry that addresses all potential needs a blaster may need in an integrated manner.This paper presents an integrated solution that takes care of all aspects of blasting – design blasts according to mine plan; collect data after drilling has been carried out (as there is often difference in designed and actual drilled hole locations in the field); predict blast results in terms of fragmentation, flyrock, ground and air vibrations, wave front reinforcement and flyrock distance; and after assessment, allows changes in charging, delay timing and sequence. The technology solution is a secure, cloud-hosted, web-based software-as-a-service solution that can be accessed from anywhere. Also it has a mobile app, which is available for both Android and iPhone/iPad. The mobile app is also integrated with the web-based solution using application programming interface calls to the central data repository.Case studies for two limestone mines are presented where this solution is being used in its initial format. This software platform enabled analysis of the outcome from a previous blast pattern and then subsequently allowed optimisation of blasting operations based on historical data. Uses of this platform have resulted in improved key performance indicators in these two limestone mines. The mobile app as part of this platform enables extensive field blast data capture and analysis and also various predictions before a blast. Data collected include blast parameters, individual hole charging, initiation pattern, videos, photographs and vibration records for analysis/reporting. The key features of the solution are a blast designer, a detailed blast data collection/analysis and a series of environmental predictors. These predictors give blast results in terms of fragmentation, flyrock, ground and air vibrations and wave front reinforcement and take remedial steps before blasting to optimise and control adverse environmental impact. Many features, such as fragmentation predictor and mobility solution, are completely unique features that are not available elsewhere in such a field personnel-friendly manner.CITATION:Bhandari, S, Parihar, C, Garg, R and Bhandari, A, 2015. An integrated technology solution for optimised and environmentally-controlled blasts, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 393–400 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By C A. Chaves

During most of its history, the metallurgical industry has been seen as a source of pollution for the environment. However, during the second half of the 20th century, as the world environmental legislation became more protective and the global environmental conscience consolidated, this landscape began to change. Metallurgical activities have become increasingly related to the social and environmental impacts caused by human activities. With the adoption of environmental management in steel plants, there has been a significant change in steel-related activities which have begun to introduce modern plants, managed with environmental, social and productive efficiency. More and more, steel companies search for a decrease in negative impacts of their industrial operations on the environment, fitting them to the current environmental legislation and even increasing productivity and profitability. The steel industry has started to become a clean and more efficient industry. This work presents a case study of a sustainable steel plant project, located in an environmental preservation area. The project includes treatment and reuse of industrial liquid effluents, air emissions control, noise control, recycling, recovery and adequate waste management. It also incorporates production processes using clean technologies, capable of coproducing energy resources which may be used in the plant showing how is it possible to produce steel with environmental and social responsibility and even increase the enterpriseÆs profitability.

Jan 1, 2009

By MattelmSki M

Outokumpu Harjavalta Metals Oy has been producing nickel since 1962, based on conventional flash smelting technology followed by electrowinning of nickel. In the 1980s, a research project was initiated to develop a converterless direct smelting process to produce matte for further refining in the then existing refinery. The process was tested on a pilot plant scale at Outokumpu's research centre in Pori and was found to be viable. The process was named the Direct Outokumpu Nickel Smelting Process or the DON Process. At the turn of the 1990s, Outokumpu studied various options to develop its nickel business and the Harjavalta operations. As a result of this work, the DON Process was further developed to produce two mattes: low iron matte in the flash furnace to be leached in the existing leaching circuit and high iron matte in the electric furnace to be leached in the new leaching circuit. In Harjavalta's case, it was essential and important that the process could use the existing flash furnace and electric furnace without converters.

Jan 1, 1996

The Henty Gold Mine is a good example of a situation where conditional simulation and optimisation techniques may have useful impact on modelling of mineralisation distribution and ore definition. Much of the gold mineralisation at Henty is concentrated within an alteration zone which is both physically discontinuous and forms only a small fraction of the overall mineralised volume. The alteration units are mappable from diamond drill core and underground workings. Conditional simulation and optimisation techniques for ore definition have found considerable success in the open pit gold mining environment. For many reasons including computational efficiency, lack of consistent geological information, and lack of familiarity with ideas and methods among mine geologists, implementations of these methods in open pit mining have been comparatively simplistic. Modelling is commonly reduced to treating the sample data as a single geologic population. This paper discusses the application of the MP method (a particular implementation of conditional simulation and optimisation) to modelling the distribution of potential ore blocks in the Henty gold mineralisation. The approach allows the mine geologist to model both the spatial geometry of the alteration types and the gold grades associated with each alteration type in a single process. Options allow the geologist to include or exclude underground geological mapping and face sampling depending mainly on the abundance of drill hole sampling and the quality of the face sampling. An optimisation algorithm based on maximisation of profit from mining is used to assist in ore definition.

Jan 1, 2000

By E Jak, G Khartcyzov, M Shevchenko

The increasing complexity of ore resources and recycled materials in the feed of pyrometallurgical processes present a technical challenge to the metallurgical engineers working on maximising the recovery of the valuable elements and minimising the environmental impact of the processes. To address this challenge, the availability of computational tools that can predict the mass and energy balance in complex systems is required. Then the accurate description of phase equilibria in the complex multicomponent systems describing the chemistry of the pyrometallurgical processes becomes critical for the correct implementation of the indicated tools and facing the outlined industrial challenges. In the present study the distribution of selected elements (Pb, Zn, Fe, As, Sn, Sb, Bi and Ni) between oxide liquid and metal in the ‘CuO0.5’-CaO-AlO1.5 system in equilibrium with Cu metal at 1400°C (liquidus of CaAl2O4) was experimentally studied using the equilibration and quenching technique followed by the electron probe X-ray microanalysis of the resulted samples. The study covered a wide range of effective p(O2) over the system from 10-11 to 10-3.5 (corresponding to formation of immiscible CuO0.5-rich slag). To avoid loss of volatile elements (Pb, Zn, As, Sn, Sb and Bi), a correlation between ‘CuO0.5’ in oxide liquid and p(O2) in open system was obtained first, followed by studying the volatile elements distribution in closed conditions (Al2O3 crucible sealed in SiO2 ampoule), where ‘CuO0.5’ concentration was used as a marker to evaluate the effective p(O2) over the system. The experimental results were then used for the optimisation of the thermodynamic model parameters of the system as part of the integrated experimental and self-consisting thermodynamic modelling research program of phase equilibria in the Cu-Pb-Zn-Fe-Ca-Si-Al-Mg-O-S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co and Na) gas/oxide liquid/matte/speiss/metal/solids system.

Jun 19, 2024

By E Jak, J Chen, B Hogg, S Nikolic, S Nicol

The quantity of post-consumer ‘waste’ materials generated each year is rapidly increasing. These materials can contain significant quantities of critical metals and present an environmental challenge if landfilled. The ISACYCLE™ technology is a proven solution for the processing of these materials. In the ISACYCLE™ furnace, the post-consumer materials are processed to recover energy along with any contained critical metals, in the form of a base metal alloy or matte. In addition, a clean aggregate (slag) is generated, which has the potential to be used for a range of applications in the construction industry. This slag is commonly based on a fayalite slag but is modified to manage the complex feed. This paper will review the fayalite slag system and the theoretical modifications required for treating urban wastes. Slags from an ISACYCLE™ furnace processing urban wastes have been sampled and characterised. The chemistry of these samples will be reviewed and compared to the expected theoretical modifications required.

Jun 19, 2024

By I Swane, R Rait, A Robertson

Geochemical assessment of mine waste materials prior to commencement of a proposed mining operation is a fundamental component of mine feasibility studies and the regulatory approvals process. Static and kinetic geochemical test methodologies are widely used to predict the geochemical nature of mine waste materials and to develop strategies for managing potentially æhostileÆ materials. These data can also be integrated with data from other fundamental studies such as hydrogeology to predict specific environmental outcomes and potential impacts at mine closure and post-closure.A case study is presented for a proposed open pit gold mine in Mongolia, which illustrates how geochemical, hydrogeological and groundwater quality data can be used as part of a geochemical modelling process to predict the final pit lake water quality over time. A series of static and kinetic test geochemical test programs were completed and acquired data integrated with hydrogeological and groundwater quality data provided by the proponent. A widely used geochemical modelling program (PHREEQC) was used to develop the geochemical model and predict water chemistry in the pit void after mine closure. Sensitivity analyses were completed to explore the effects on the model output of groundwater to leachate water ratio, pit wall rock type and climate.Modelling has indicated that pit void water should be pH circum-neutral at mine closure and should remain within Mongolian and World Bank water quality guideline limits under the modelled simulation most likely to occur in the field. Final void water salinity is expected to increase eight fold over 14 years after end of mine life due to a continuous flux of salts (particularly sulfate salts) into the pit lake whilst the pit lake volume will remain relatively constant due to evaporation and a slow recharge rate. Dissolved metal and sulfate salt concentrations in pit water are also predicted to increase over time and could be moderately elevated compared to applied water quality guideline values. Some of the metal concentrations, however, may be lower as these would be expected to precipitate at circum-neutral pH and greater. Recommended additional assessment work on the project when mining commences includes determining the magnitude of adsorption and co-precipitation of metals occurring in the pit void water/sludge system.CITATION:Robertson, A, Rait, R and Swane, I, 2013. Geochemical assessment of mine waste materials and prediction of final pit lake water quality at a proposed gold mine in Mongolia, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 165-170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By F Brenguier, R A. Lynch, G Olivier

The seismic velocities of intact rock are dependent on the applied stress. Unfortunately, the low susceptibility of seismic velocity to stress changes mean that changes in seismic velocity have to be measured extremely accurately to infer stress changes from them. Previously, it was thought that measurements of this accuracy could only be made with active sources or repeating earthquakes. In this paper, we show that the noise generated by mining activity can be used to construct virtual seismic signals with which we can measure changes in seismic velocity accurately enough to see the short- and long-term effects of a production blast on the surrounding medium. The time-dependent velocity variations achieved with this method show that the blast caused weakening of the rock mass for the rock within a radius of 200 m of the blast. The weakening is healed by confining stresses over a period of five days, after which permanent changes in the seismic velocity can be seen. The size and spatial distribution of the seismic velocity changes were compared to modelled changes in static volumetric stress, which supported the notion that seismic velocity changes can be used to measure the redistribution of stress after a blast. The results of this study indicate that this method can be a powerful tool to evaluate the evolution of stress in a mine at a relatively low cost as the data that it uses would normally be discarded.CITATION:Olivier, G, Lynch, R A and Brenguier, F, 2016. Measuring the redistribution of stresses resulting from new excavations with ambient seismic noise correlations, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 873–878 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By D Kubik, K The

The New Zealand (NZ) Transport Agency’s Waterview Connection will complete Auckland’s Western Ring Route, a 47 km north–south motorway alternative to Stage Highway 1. The project is being delivered by the Well-Connected Alliance comprising the New Zealand Transport Agency (NZTA), Fletcher Construction, McConnell Dowell Constructors, Obayashi Corporation, Parsons Brinckerhoff NZ, Beca Infrastructure and Tonkin & Taylor.The project involves construction of 5 km of new motorway, nearly half of it underground connecting State Highway 20 (SH20) to State Highway 16 (SH16). The underground portion of the project incorporates twin 13.2 m inside diameter (ID) tunnels 2.4 km long, each carrying three traffic lanes, one for north-bound traffic and one for south-bound traffic. The tunnels are being driven by a 14.46 m outside diameter (OD) 2400 t, tunnel boring machine (TBM) shield that was assembled and launched at the southern portal. It will be turned and re-launched at the northern portal for the return drive to the southern portal where it will be disassembled. This paper presents two major temporary works elements contributing to the successful launch of the TBM: the TBM assembly crane platform and the TBM shove frame and associated components.Tunnel boring machine shield assembly – crane platformThe TBM shield was delivered to site in subassemblies ranging in weight from 100 to 380 t. It was initially proposed to use a 750 t crawler crane sitting above the tunnel portal headwall to assemble and disassemble the TBM. However, this did not have sufficient capacity to allow the TBM shield to advance clear of the tunnel before disassembly commences. To reduce the crane’s working radius a temporary steel crane platform was developed that is supported on the side walls of the tunnel approach trench. This has enabled a smaller, less expensive, 600 t crawler crane to be used and will allow the TBM shield to clear the tunnel before disassembly.Tunnel boring machine launch – temporary worksTo launch the TBM a purpose built steel frame was required for the TBM thrust rams to react against. The shove frame had to be able to transfer the thrust loads from the TBM shield to the ground below and thrust wall behind. A range of potential thrust loads and jacking patterns were examined to develop the design load cases for the shove frame. The shove frame was used to launch the TBM at the southern portal and to re-launch it at the northern portal. Elements of the shove frame will also be used to support the portal faces during the TBM arrivals.CITATION:Kubik, D and The, K, 2014. Waterview Connection – temporary works for tunnel boring machine?launching, in Proceedings 15th Australasian Tunnelling Conference 2014, pp 281–288 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By M G. Shaw, M A. Rhamdhani, S P. Singh, A R. Duffy, B Eisenbart, A K. Shukla, G A. Brooks

The field of astrometallurgy is a growing area of study. Metal production on the Moon is likely to begin in less than a decade as major space agencies such as NASA (National Aeronautics and Space Administration) and CNSA (China National Space Administration) are preparing to construct permanent lunar bases. The utilisation of regolith to generate oxygen and metals is expected to be important in the development of a sustainable lunar habitat. This paper provides an overview of potential metallurgical processing methods for lunar conditions, emphasising the impact of lunar factors on slag chemistry. The interaction between regolith and the extracted metals, as well as their impact on slag composition and refractory performance, are critical considerations in metal production on the lunar surface. The initial research on lunar metallurgical technologies is focused on oxygen extraction and Fe-Si alloys are reported as the by-products of these processes. This paper delves into the fundamental thermodynamics associated with the carbothermic reduction of lunar regolith. Thermodynamic analysis using the FactSage™ ver 8.2 software package indicates that the Fe-Si alloy can be produced as a metallic product from the lunar regolith at temperatures ranging from 1400°C to 1600°C under terrestrial conditions. However, under ultra-high vacuum conditions (3 × 10-15 bar) on the Moon, the required operating temperature for producing ferrosilicon would be significantly reduced. Thermodynamic modelling results indicate that under lunar vacuum conditions, Fe-Si alloys only exist as solid phases at lower temperatures below 650°C. At higher temperatures, both Fe and Si are expected to be present in the gas phase. In this work, the carbothermic reduction of the Lunar Mare Simulant (LMS-1) is conducted under terrestrial conditions. The findings indicate that the process can readily yield Fe-Si alloys with 7–10 wt per cent Si at 1600°C. Additionally, energy dispersive spectroscopy (EDS) analysis of the resulting Fe-Si alloy indicates the presence of phosphorus up to 1 wt per cent.

Aug 21, 2024

Lihir Gold Mine is situated in a dormant volcanic caldera on a small island off PNG. Not æextinctÆ but dormant. Current ground temperatures are up to 150 degrees Celsius with active geysers in the workings of the mine, pools of boiling ground water adjacent to low-grade dumps and hydrogen sulphide gas emissions. It is a unique mining environment by world standards. This paper will deal with the following issues encountered and managed by the operation:blasting in hot and reactive ground; management of sulphide gas emissions; disposal at sea of all mining waste rock; one dear to all Australian minerÆs hearts û dealing with landowner groups; and unusual human resource issues.

Jan 1, 1999

By F H. Henrfquez, A G. Oroz

Design and operating conditions of large size mechanical flotation cells were evaluated by comparing them with actual operating conditions in a plant. The objective was to determine the time scale-up factor, typically based on empirical rules. Experiments were conducted on the rougher flotation circuit at Minera Escondida Ltd. The circuit consisted of self-aerated mechanical cells of 160 m3, arranged in six parallel banks with nine cells each. The rougher circuit flotation kinetics were evaluated from direct sampling and local mass balances around each cell of the bank. Adjusted overall mass balances were also developed. This information was used to fit different kinetic flotation models, and it was found that the rectangular distribution function was the most appropriate to describe the distributed rate constant for industrial operation. Then, a rougher flotation simulator was developed to describe the actual operation in terms of the operating variables (mass flowrate, solid percentage, feed grade) and the actual volumetric flowrate entering to each cell. In this study feed pulp samples were taken in parallel from the rougher circuit and were simultaneously floated in the laboratory. The kinetic behaviour was then modelled at a laboratory batch scale in order to determine the time scale-up factor between laboratory batch flotation data and industrial size flotation. The time scale-up factor observed for large sized cells, 160 m3, was found to be reasonably similar to those previously determined for self-aerated mechanical cells, but of lower size, operating at similar recoveries. In addition, the relative effect of mixing, between laboratory batch and an industrial flotation bank, was quantified by the parameter, separating the impact that kinetic and mixing changes have on the time scale-up factor. In general, the rougher flotation operation was found to reach the predicted metallurgical target, and the optimal separability criterion was also respected. The diagnostic generates information about the internal state of the process and helps to identify potential improvements for design, operation and control of the circuit.

Jan 1, 2005

By Schaap W

A test on Taylor's rule of mine life using published data on open pit porphyry copper mines confirmed that mine life is, on average proportional to the fourth root of reserve tonnage. Deviations from this rule-of-thumb occur to a large extent as variations between regions that are qualitatively explained in terms of differences in grade, infrastructural needs or special taxation effects.

Jan 1, 1984

By M Haydon

How do you portray a large structurally and stratigraphically complex deposit to return a meaningful resource estimation, and produce a geological model that is useable for planning on a daily basis? The George Fisher Mine is located 22 km north of Mount Isa and forms part of XstrataÆs Zinc Group operations. It is currently a major producer of zinc, lead and silver in the region with an estimated total resource for all categories of 127 Mt at 100g/t Ag, 5.3 per cent Pb and 9.2 per cent Zn (June 2005). Production in 2005 totalled 2 647 492 wet tonnes for 317 699 kg Ag, 140 317 tonnes Pb and 230 331 tonnes Zn from underground operations. George Fisher (GF) consists of two deposits that are structurally complex on a mine scale, George Fisher North (GFN) and George Fisher South (GFS). Regional faulting has resulted in a 2 km long package of variably pyritic shale and siltstone that separates the deposits. This paper looks specifically at GFN. Distinct correlations exist between the two deposits based on stratigraphic matches; however, orebody characteristics, geometry and fault architectures differ significantly between the two. The deposits consist of multiple, sedimentary-hosted, stratiform orebodies from 2 to 25 m wide, separated by waste intervals of variable width. Each ore-waste interval is modelled as an individual geological domain. Structurally, George Fisher North (GFN) contains a series of major late-stage NE faults with dextral offset(s) of up to 130 m. Further complexity is added by NS, NW and NNE striking fault orientations that can produce either a loss or repeat of stratigraphy, local drag folding, orebody attenuation and block rotation. Due to this structural complexity and orebody offsets, domains at GFN are further divided into fault blocks (FB). The GFN model comprises eight FBs over a strike length of 1 km, all of which are modelled independently. As drilling progresses and additional resources are converted, further FBs will be added at major fault offsets to accommodate orebody and model expansion. This will be in addition to what is already a large and time-consuming data set to manage and update. For example, each FB has 18 domains each with two constraining wireframes (hanging wall and footwall). Each wireframe has several sets of point data depending on the type of data available, ie diamond drilling, mapping or interpretation points. This equates to over 1100 separate files to manage. Additional wireframes and files are also required for major structures, daily planning requirements and block model runs. In total some 1500 files are managed, updated and maintained for GFN alone. The ongoing need to expand as a business and optimise production in the current economic climate where there is a global demand for metal has led to an increase in production at GF. This has resulted in a rapidly growing data set and highlights the importance of practical and efficient modelling to achieve a meaningful resource estimate. This paper focuses on the geological modelling, modelling approaches and techniques employed for the GFN deposit.

Jan 1, 2006

By C J. Unger, T Baumgartl, C J. Bond, P Sabourenkov, V C. Glenn

Social licence to mine is influenced by society’s perception of the mining sector’s ability to effectively rehabilitate mined land and for governments to appropriately regulate that process for the broader community benefit. In Queensland, Australia, many mine rehabilitation personnel working for active coalmines, as either staff, consultants or contractors, belong to the Central Queensland Mine Rehabilitation Group (CQMRG). The CQMRG was established 23 years ago with the aim of sharing informal knowledge related to practical aspects of rehabilitation in order to leave as positive a legacy as possible from mined land. This voluntary group of professionals also includes members from regulatory agencies and civil society. Within the dynamic regional mining environment, mine rehabilitation professionals benefit from sharing their informal knowledge.CQMRG is currently a group in transition. Mining boom and downturn cycles have exacerbated the loss of accumulated knowledge in the core CQMRG membership due to rapid changes in personnel at mines in the region. Additionally, some of the most experienced CQMRG-affiliated rehabilitation practitioners are approaching the end of their careers and want their valuable and less formal knowledge retained. This paper discusses the development of a research project that emerged in response to the anticipated loss of several decades’ worth of valuable knowledge as rehabilitation practitioners in CQMRG left the region or the workforce.CITATION:Unger, C J, Bond, C J, Baumgartl, T, Glenn, V C and Sabourenkov, P, 2016. ‘MRC-wiki’ – a mine rehabilitation and closure knowledge management tool for Central Queensland coalmine practitioners, in Proceedings Life-of-Mine 2016 Conference , pp 39–42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By L Mikhael Gurieff, D Baas

The Phu Kham Copper-Gold Operation (Phu Kham Operation) is located in the Lao People's Democratic Republic and is owned and operated by the Lao-registered company, Phu Bia Mining Limited (PBM). Australian-headquartered copper and gold producer, PanAust Limited holds a 90 per cent interest in PBM; the Government of Laos owns the remaining 10 per cent. The Phu Kham Operation was commissioned in 2008 with an initial concentrator nameplate throughput of 12 million tonnes per annum (Mt/a). Subsequent improvement projects, including the Phu Kham Upgrade Project (PKU), completed in 2012, and the Phu Kham Increased Recovery Project (IRP), completed in 2013, increased the design throughput to 18 Mt/yr. In 2016, the actual mill throughput exceeded 19 Mt/a, this throughput is budgeted to be maintained until the end of 2020.The concentrator flotation circuit upgrade, completed during the IRP, called for a non-selective bulk sulphide concentrate to be generated from the rougher circuit. This in turn caused the mechanical flotation cells in the cleaner circuit, particularly those in the second cleaner bank, to become volumetrically overload. The overload reduced the cleaner circuit performance to approximately 92 per cent copper recovery at a 23 per cent copper concentrate grade, below the expected 95 per cent recovery. This bottleneck restricted copper units entering the plant to approximately 14.5 tonnes per hour (t/h) due to uncontrolled recirculating load build-up in the mechanical cleaning circuit.Maintaining the operating methodologies would have led to a copper production shortfall beyond 2016, to address this shortfall the Phu Kham Operation looked to optimise the Jameson Cell and mechanical cleaner circuit performance. The work included fundamental application of flotation practice and modelling, mineralogical analysis, bubble size analysis, plant surveys and test work. The results were used to develop and implement an innovative automated control system strategy incorporating flotation theory and operating strategies. The automation has the ability to quickly adapt to disturbances in the circuit and maintain optimised performance with little or no intervention by flotation operators.Upon completion, cleaner recovery increased to 95 per cent at a final concentrate grade of 23 per cent copper, and copper units entering the plant increased to 17.5 t/h.CITATION:Baas, D and Mikhael Gurieff, L, 2018. Developing flotation circuit control and automation for the Phu Kham Copper-Gold Operation concentrator, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 37–58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By L O. Filippov, A Piçarra, I V. Filippova, N P. Lima, K Silva

The reverse cationic flotation using the starch as depressor of iron oxides is the most efficient upgrading process when is applied to the simple systems composed by hematite/magnetite and quartz. The fundamental studies performed with iron ore samples from different deposits over the world (Brazil, Russia, Mexico) confirmed the inefficiency of starch when the silica content in the concentrate is controlled by Fe/Mg-bearing minerals. The main approaches for solving these issues focused on using new collector formulations or new depressants. However, the alternative depressants tested inhibited flotation of quartz or were less efficient as iron oxide depressant. In this work, a comparison between new amidoamine collector with conventionally used etheramine and oleate collectors in the flotation of pure minerals and actual iron ore samples was performed. The electrophoretic mobility, contact angle and infrared spectroscopy measurements allowed to deduce the hindrance effect as main mechanism of selective adsorption of the amidoamine on the quartz surface compared to hematite and kaolinite. Molecular modelling studies revealed that this steric hindrance effect can be explained by the combination of the "shield" formed by the coordinating water molecules on the (001)-D2 hematite surface and the large volume of the amidoamine head group. The amidoamine tested as collector without use of a depressant showed excellent flotation selectivity allowing the total flotation of quartz from a mixture with hematite. High collector performance and selectivity were confirmed during reverse flotation of quartz using continuous flotation column (D = 500 mm; H = 4000 mm) and allowed to produce the iron concentrates with more than 60 per cent of iron from the rejected slimes samples of Vargem Grande 2 processing plant (Iron Quadrangle, MG, Brazil). The new collector allowed to develop flexible flotation flow sheets to process the iron ore with a complex gangue mineralogy and unlock the old altered tailings and slimes product as new resources

Aug 24, 2022

Commercial explosives range from pure emulsions to pure ANFO, with blends of these providing interesting alternatives: energy is often adjusted through addition of aluminium, or the control of density. The energy rating of explosives is derived chiefly from detonation codes, which are used to derive expressions for the internal energy change of the detonation products as they do work under expansion. While all codes used for this purpose work on the basis of Ideal detonation, it is common knowledge that commercial explosives operate in the Non-Ideal domain, which affects the mode of energy delivery to the environment. However, since Ideality represents the foundation from which actual performance evolves, it is valuable to examine the intrinsic energy release of a formulation before attempting to understand the influence of Non-Ideality. In examining the Ideal pressure profile of fundamental formulations, remarkable correlation has been found with field performance, and this increases understanding of the influence of various formulation modifications, especially in regard to the stage at which energy is released, and the effect on rockbreaking. This work has emphasised the value of attempting to understand and define better the non-ideal detonation process.

Jan 1, 2001

By V Malysiak, N J. Shackleton

In the flotation of platinum group minerals pyroxene is a major gangue mineral. This study shows using zeta potential and ToF-SIMS analyses that when pyroxene is exposed to copper, nickel and/or calcium ions in solution at alkaline pHs a surface reaction occurs between the hydroxy species, in the case of copper and nickel, or divalent calcium ions and the pyroxene surface which influences the floatability of the pyroxene. Following exposure to copper and nickel ions at pH 9 addition of SIBX resulted in the pyroxene floating readily. It is also shown, in the case of copper, that the activating effect of the adsorbed copper hydroxy species can be reduced by the addition of complexing amines prior to SIBX. Proposals are made to explain these observations.

Jan 1, 2005

By A Giblett, B Putland

This paper provides a simple guiding framework for grinding circuit optimisation, focussing on common themes in past optimisation success stories, the conditions for success and techniques that can be employed to identify and define opportunities. Many significant grinding circuit improvements have been reported for operating plants, based on recurring themes such as the optimisation of mill feed size, mill liner design, process control, critical size, grinding media and classification. The paper condenses these experiences into a set of simple questions for the operator to ask, and provides guidance towards identifying and achieving the optimisation goals.CITATION:Giblett, A and Putland, B, 2018. The basics of grinding circuit optimisation, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 129–140 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018