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By M Fuchs

Roadheaders were introduced to mining and tunnelling in the early-1960s. Since this period their main field of application has been for roadway drivages in coal mines and for mineral production, for instance in coal, rocksalt, potash and gypsum mines. Their main field of application in tunnelling is in softer and partly friable rock formations, a suitable area for non-blasting excavation. However, in longer tunnel sections excavators with high ripping forces have replaced roadheaders in many situations. The main arguments against roadheaders have been and still are:a sharp increase in excavation cost with increasing rock strength and increasing abrasivity; and greater risks in conditions which have not been, or could not be, investigated to a sufficient extent. These arguments have, to a great extent, restricted practical roadheader application in production mining and in a lot of æstandardÆ tunnel projects. To address these limitations, factors which could make roadheaders attractive for such conditions and could overcome existing technological difficulties have been investigated. Extension of the economic field of application in hard rock was found to be the most important and the most effective step forward.

Jan 1, 2002

By J-P Franzidis

A technique for determining the recovery of attached particles across the froth phase in flotation that relies on measuring the rate at which bubble-particle aggregates enter the froth is used to investigate the selectivity of attached particles across the froth phase. Combining these measurements with those of other techniques for determining the froth recovery of attached particles provides an insight into the different subprocesses of particle rejection in the froth phase. The results of experiments conducted in a 3 m3 Outokumpu tank cell show that the detachment of particles from aggregates in the froth phase occurs largely at the pulp-froth interface. In particular it is shown that the pulp-froth interface selectively detaches particles from aggregates according to their physical attributes.

Jan 1, 2005

By M Grigorescu, J H. Hodgkinson, M Khanal

The mining industry often needs to operate in remote or climatically harsh locations. The industry has recently been forced to deal with extreme conditions including floods, heatwaves and droughts. As these are becoming progressively frequent occurrences, mines typically build ‘downtime’ into production schedules and expect to incur costs to manage the various risks arising from climate extremes. Importantly, many environmental conditions are becoming more extreme and consequently, risk management based on past data can become increasingly ineffective. Market and shareholder demand for fewer interruptions are another pressure on mines to avoid prolonged or frequent downtime. Hence, adaptation to climate is becoming an important strategic move for many companies, many of whom are using future climate scenarios and alternative risk evaluations.We present here a method that uses commonly available mine site data to assist decision-making for reducing vulnerability to sudden flood. The method, ‘climate-related adaptation from terrain evaluation results’ (CRATER), identifies a mine’s flood ‘hot-spots’ and presents them as a ‘traffic lights’ warning map. The process then requires a failure analysis process such as fault-tree analysis to identify both the cause of possible failures and a range of possible failure-avoidance adaptations. In the final stage, management can assess the most suitable option for the mine, based on the availability of capital such as time, facilities, labour and money in addition to social acceptability of the options. CRATER has been tested in an open cut mine environment and is now being further developed to identify how subsidence over underground mines may impact on flooding and ponding over the mining life cycle (CRATER II). Further work is continuing to test larger and more complex mine landscapes to deliver a method to extract more knowledge from existing data.CITATION:Hodgkinson, J H, Grigorescu, M and Khanal, M, 2016. Reducing mine site extreme rainfall vulnerability using climate-related adaptation from terrain evaluation results, in Proceedings International Mine Management Conference, pp 187-200 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By C E. Loo

The cohesive zone has a significant influence on blast furnace operation and performance. The high-temperature behaviour of the reducing ferrous burden determines the properties of the cohesive zone and is studied in a laboratory using a softening and melting test. This paper summarises recent work aimed at better understanding the physico-chemical changes in a ferrous bed during softening and melting. Using a combination of standard, non-standard and quenched tests supported by optical image analysis, this work has highlighted some important differences in behaviour between lump, pellets and sinter as well as between the two lump ores and two acid pellets. As with the two lump ores, one pellet is denser than the other and the denser ore/pellet is also higher in silica.Within the cohesive zone, densification of the ferrous layer leads to reduced permeability and greater pressure drop. From the work presented in this paper, two key mechanisms of ferrous layer densification were identified. Firstly, the formation of fayalite, which melts at low temperatures, can act as a lubricant between particles and lead to densification of the ferrous layer under load. Secondly, reduction to metallic iron is topochemical and fayalite in the outer shell of the particle restricts gas flow to the centre and results in the formation of a wustite core. As temperatures rise, the wustite melts and eventually exudes out of the shell, occupying void spaces between particles and further reducing layer voidage and permeability.This work has shown that density and silica content are two key factors that result in increased densification of the ferrous layer. For porous Australian lump ore, the higher porosity and lower silica reduces the formation of fayalite and limits the formation of the wustite core, ultimately leading to a more permeable bed. The difference between the porous and dense ores was more pronounced with the introduction of prereduction to better simulate blast furnace conditions. This suggests that a porous ore gives significantly better cohesive zone permeability and blast furnace operations than a dense ore.The behaviour of fluxed sinter particles is different in that the silica reacts with lime to form dicalcium silicate. Minimal wustite core forms because relict hematite particles in sinter are only small and reduction occurs uniformly throughout the particle. Even with significant loss of material through prereduction, beds formed from sinter remained comparatively rigid. Studies using a typical blast furnace burden mix of 80 per cent fluxed sinter and 20 per cent porous ore showed that the structures of these beds at softening and melting temperatures are very similar to the sinter-only test. Measurements of bed contraction and pressure drop also confirmed that the introduction of 20 per cent porous ore into a sinter bed did not alter its properties. This is an indication that 20 per cent ore can be easily accommodated by blast furnace burdens.CITATION:Loo, C E, 2015. Important acid ferrous burden properties in the cohesive zone of a blast furnace, in Proceedings Iron Ore 2015, pp 367–376 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By A McKay

The Great Artesian Basin (the Basin) is a large aquifer system underlying more than 20 per cent of continental Australia and most of Queensland. The aquifers of the Basin are an important water source for many industries, including the mining sector. The Queensland Great Artesian Basin Water Resource Plan (the Plan) was released in March 2006. The Plan provides a framework for the long- term holistic management of the aquifers in the Queensland Section of the Basin, in a manner that is consistent with the strategic management plan for the Basin as a whole. The paper describes the Basin and summarises trends in the demand for water in the Queensland section of the Basin. It describes the broad framework for management of the Basin by the individual Australian states, as well as the planning entitlement framework for water resource management in Queensland. The paper discusses the content of the Plan. This includes: the division of the aquifers into management areas and management units for management purposes, provision for protection of the flow of water to springs, limits on further allocating water, provision for a competitive process for access to new water and provision for water trading. Under the Queensland planning and entitlement system a resource operations plan is prepared to specify operational arrangements to implement a water resource plan. A resource operation plan for the basin is expected to be finalised before the end of 2006. The paper summarises the likely content of the plan.

Jan 1, 2006

By T Blyth, D Holden, N Archibald, S Huffadi

The Morning Star mine is owned by Hill 50 Gold NL. Gold is hosted in quartz-carbonate ¦stibnite ¦molybdenite veins that occur in a series of deformed, altered and metamorphosed mafic volcanics with subordinate sediments and felsic intrusive rocks. The irregular gold distribution and its relationship to structure and alteration intensity makes the definition of stoping limits difficult. Understanding the structural evolution of the orebodies and the contemporaneous and later structures that affect the orebodies has been very useful in this context. This paper reports on a detailed mapping exercise (as part of a more extensive and on-going investigation) and the integration of this mapping with other geological and grade control data in a 3D modelling environment to provide an expanded basis for stope design. Three types of mineralised zones can be discriminated based on the morphology of the veins within. They are:those associated with strongly folded, thick veins (approximately 1 m thick eg 05 orebody); those comprising planar, boudinaged and some folded veins which consolidate to form tabular, steeply dipping bodies (eg 010 orebody); and zones containing the above vein types and thin, highly deformed veins within zones of intensely foliated country rock that result in localised, irregularly distributed high-grade gold zones (eg 02 orebody). The mineralised zones associated with thick folded veins are typically predictable over many tens of vertical metres. The second and third types of ore zone is generally less predictable. Detailed mapping and structural kinematic studies indicate all ore zone types are affected by progressive deformation involving strong strain partitioning. It is interpreted that high strain zones, recognisable by intense foliation development and highly deformed veins, are the latest stage of a progressive deformation which approximates bulk flattening. Structural controls on mineralisation can be defined at two different scales.Regional scale folding has deformed a sequence of mafic volcanics with interlayered sediments and felsic intrusives. Initial geometry of felsic bodies relative to orientation of the primary lithological layering and the bulk shortening direction is interpreted to be critical for initiation and development of strongly dilatant zones within this package of rocks, and Local scale dilation is evidenced by development of several vein sets whose range in orientations and opposed vergence relationships suggest a pre-folding origin comprising both extensional and hybrid shear-extensional types. Continued deformation resulted in folding of these veins with strong strain partitioning. Major vein packages are closely spatially associated with the felsic/mafic contact and an interpreted early structure which appears to have partitioned early dilation. This structure is now obscured by strong deformation but is currently represented by a zone of planar veins.

Jan 1, 2000

By T Raynlyn, A Edenton, M Adam, R J. Holmes, J R. Manuel, N Ware, R Smyth

Due to ongoing demand and increasing depletion of high-grade iron ore resources from large deposits, Australian iron ore producers are developing smaller size deposits to maintain current export levels. The iron grade, mineralogy, chemical and physical characteristics of iron ore fines being mined from different deposits vary considerably. It is therefore imperative to develop long-term strategies to maintain the quality and consistency of iron ore fines while moving to a larger diversity of smaller deposits. Blending is a common practice in sinter plants as it is almost impossible to produce a high performance sinter mixture displaying the required characteristics from one single ore. Blending is also one of the most effective options being used by iron ore producers to ensure the long-term stability of their products while increasing production. When designing a blend, the blend components are selected to support each other to achieve the required overall balanced metallurgical performance of the final product at a relatively low cost. To do so, a fundamental understanding of the key characteristics of iron ore fines and their potential impacts on the iron ore sintering process and sinter quality are required. In this paper, the sintering process and sinter structure have been analysed and the key factors affecting the sintering performance of iron ore fines, including productivity and quality, identified. Under fixed sintering conditions, the granulation efficiency, nuclei stability and the volume and properties of the primary sinter melt are believed to have important impacts on both sintering productivity and sinter quality. Discussion is then focused on the effects of ore chemical, physical and mineralogical characteristics on the key factors identified and in turn the consequences for sintering productivity and sinter quality.

Jan 1, 2009

By J Zhang, O Ostrovski, C Zhang D Cai, Q Wang

The conventional CaO-SiO2-based mould fluxes are not suitable for high-Al steel casting because of the strong reaction between silica in the flux and aluminium in the steel strand. In the process of casting of high-Al steel, flux composition changes; with the decrease of the silica concentration and increase of alumina. Knowledge and understanding of the effect of the Al2O3/SiO2 ratio on flux structure and properties are useful for flux design for the high Al-steel continuous casting. This paper investigated the effect of the Al2O3/SiO2 ratio on structure, viscosity, phase composition of fluxes quenched at different temperatures and heat transfer of CaO-Al2O3-SiO2-B2O3-Na2O-Li2OMgO- F fluxes. It was found that flux melting temperature increased with the increase in Al2O3/SiO2 ratio. Viscosity of the flux melts increased significantly with the increase of the Al2O3/SiO2 ratio from 0.7 to 1.2, reaching the maximum value, and then decreased with further increase of the Al2O3/SiO2 ratio. Raman spectroscopy analysis revealed that the change of the Al2O3/SiO2 ratio led to the change of aluminate and silicate structural units. The turning point for viscosity was attributed to the change in the degree of flux polymerisation. X-ray diffraction (XRD) analysis showed that increasing Al2O3/SiO2 ratio increased crystallisation tendency of the fluxes. Heat transfer measurement by infrared emitter technique (IET) revealed that increasing Al2O3/SiO2 ratio led to the decrease in heat flux which is correlated well with the increased crystallinity of the flux. The results suggested that the flux with Al2O3/SiO2 ratio 4.3 is the best candidate among the studied CaO-Al2O3-based mould fluxes for casting of high-Al steel.

Aug 21, 2024

By D Giurco

As part of global systems of mineral production and consumption, the Australian minerals sector is facing sustainability challenges across technological, social, ecological, economic and governance domains, as well as between local, national and global scales. To ensure that the Australian minerals sector progresses towards sustainability, it is imperative to understand the possible ways in which AustraliaÆs mineral resources could support sustainable futures. A significant research gap exists between the complex nature of questions concerning minerals sustainability and the reductionist methods available to deal with them. This paper argues the need for broader, more integrated approaches to questions concerning minerals sustainability, which can address multiple human perspectives, complex and æmessyÆ patterns and processes across multiple organisational, temporal and geographical scales and whole systems of mineral production and consumption. To inform the development of a new approach to minerals sustainability, this work reviews the contemporary understanding of the Australian minerals sustainability problematic, from the perspective of the Australian minerals sector (Minerals Council of Australia), the Australian research sector (Mudd 2007a, 2007b; Mudd and Ward 2008) and a multi-scale international project (MMSD 2002). This review shows the focus of current responses to the minerals sustainability problematic, identifies the need for an integrated approach to questions of minerals sustainability and addresses how different approaches are informed by underlying and unarticulated assumptions about the tolerability of tradeoffs between different societal goals, the treatment of uncertainty and the application of different conceptual geographical, organisational, temporal and life cycle scales to define the minerals sustainability problematic. The Mineral Resources Landscape proposed, offers an expanded conceptualisation of minerals sustainability, to link minerals production and consumption in an integrated assessment across the entire minerals supply chain, connecting social, ecological, technological, economic and governance domains across local, national and global scales. The key leverage points governing change in the Mineral Resources Landscape are identified as: the material source, extraction and production technologies, level of service and value, and consumption patterns. Mapping the key challenges facing the minerals sector, as identified in the review herein, indicates that the boundaries defining traditional conceptualisations of minerals sustainability focus on the material source and technology and ignore two very key drivers of the Mineral Resources Landscape û the æservicesÆ minerals offer to society and the æconsumption trendsÆ which assimilate these services into society. Understanding these overlooked aspects of the Mineral Resources Landscape, along with the conventional areas of focus, is essential for identifying the Australian minerals sector as a provider of sustainable mineral services. This insight prompts a reconsideration of the role of minerals services and consumption trends, together with the role of the material source and technology in shaping change and the emergence of sustainable systems of Australian minerals production and consumption, across multiple scales and domains.

Jan 1, 2009

By S Basu, P M. Midhun

Electro-Slag Remelting (ESR) is a process capable of producing ingots with much lower centre-line segregation and better internal soundness than conventional ingot casting processes, as well as lower inclusion and sulfur concentrations. This process is commonly used for alloyed steels intended for critical applications like components of marine turbines, supercritical powerplants and rocket motor casings. It involves melting a metal electrode using electrical resistive heating in a slag pool and re-solidification of the resulting metal droplets beneath the slag layer, forming an ingot. Conventional ESR fluxes consist primarily of CaF2, Al2O3 and CaO, along with minor concentrations of SiO2, MgO etc. The emission of fluoride vapour from the molten slag causes several environmental and health problems, triggering a need to develop and reduce the fluoride content in the ESR flux. The present study aims to develop low-CaF2 alternatives to commercial ESR fluxes without compromising on productivity and the surface quality of the refined ingot. Thus, the modification in chemical composition needs to satisfy properties like electrical resistivity, viscosity and liquidus temperature, essential for efficient ESR operation. Since electrical resistivity and viscosity are highly dependent on the ionic structure of the molten slag, it is important to understand the effect of compositional modification on the structure of the flux. The present study employs Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy to investigate the structural variations in the modified fluxes, especially the effect of changing SiO2 concentration, in comparison with conventional CaF2-rich fluxes. Additionally, thermal analysis (Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA)) has been carried out to characterise the melting behaviour of the fluxes. The findings are compared with simulations carried out using the FactSage™ software, ver 8.3 (GTT Technologies, Aachen, Germany). Simultaneous analysis of liquidus temperature and the structure is expected to help in identifying the practical suitability of modified ESR flux compositions for industrial implementation.

Jun 19, 2024

Computers are playing an increasing role in the management of technical data in mines. Companies are re-assessing the role of their data processing departments as users demand computer resources in non-accounting areas. Data of all kinds is now being seen as a, company resource, and the role of computing professionals is to help to manage the data flow, not merely to manage computers. The concept of distributed data bases puts the responsibility for data entry, editing and updating with the user. This challenges conservative views of centralized control of computing, suggesting, instead, centralized co-ordination. A survey of the possible applications of computers in technical areas points up the special requirements of handling raw, processed and consolidated technical data. Technical data bases have become flexible as mini- computer hardware and software have rapidly developed. Management has the ultimate responsibility for efficiently administering corporate data bases, and it must ensure suitable policies are developed for this purpose, with enough flexibility to cope with the impact of fast changing technology.

Jan 1, 1980

By P O. Andersson

Mining of sill pillars is more difficult than the ordinary mining. The sill pillar mining is performed under more difficult conditions and the mining of the sill pillar itself produces more problems; failure of the rock due to high stresses, difficulties in controlling the fill above, overall stability of the stope and special requirements on the technique for backfilling. Altogether this makes sill pillar mining technically difficult and often not profitable. A project was therefore initiated with the aim to increase the mineable ore reserve by making sill pillars mineable, both technically and economically. The project aimed at developing technique for already existing sill pillars as well as planned sill pillars. For the existing sill pillars a technique would have to be developed for mining beneath unstabilised fill. For sill pillars that would be created in the future, the most suitable mining method and methods of supporting or stabilising the fill in the stope above was to be chosen within the project.

Jan 1, 1998

Many parameters are important when considering the performance of a concentrator. These include metallurgical performance, such as throughput, metal recovery and final concentrate grade and operating costs, such as power consumption, water usage, reagents and spare parts. In most operations the objective is to maximise metallurgical performance and minimise operating costs, ideally without a large investment in new capital items. A number of projects have been carried out at Newcrest MiningÆs Cadia Valley Operations (CVO) with the aim of improving metallurgical performance and minimising operating costs. This paper focuses on the installation of newly designed flotation mechanisms in various cells in the Cadia flotation circuit and describes the effect these changes had on performance and operating costs.

Jan 1, 2009

MR. L. C. BALL, chief government geologist, Queensland, wrote: This paper is intended as a severely mechanical exposition of the means adopted to deal with tremendous inflows of water concurrently with development and exploitation; but incidentally it serves as a splendid exposition of close co-operation maintained between the geological and engineering branches of this large organization.I have been impressed by the completeness of the mine plans of 'Mount Isa Mines Ltd.; but only such a paper as this has brought fully to my understanding the difficulty and complexity of the solid geometry involved in the detection and plotting of the orebodies and their stratigraphic control, including faults and large-scale brecciations, and the managerial foresight that set going the initial investigations.The company's geological branch of course must be given full credit for the results attained, but it gives me pleasure that the Geological Survey of Queensland has been closely associated in much of the study.It is noted that complete drainage was affected, but it would be interesting to learn whether the brecciated zone will again become waterlogged and whether from above or from below, and whether there has been any change in the dissolved mineral content of the water as the work progressed.

Jan 1, 1939

By W T. Pate, A V. Potapov, J K. Lichter

Even though flotation is one of the most important unit operations of mineral processing, accurate modelling of this process for plant performance prediction has remained elusive. In the last four to five years dramatic changes have occurred in our ability to make credible model based predictions. This paper briefly traces the history of flotation modelling from simple (lumped pulp-froth) æchemical kinetic analogueÆ models for single cells to more detailed multi-phase, multi-component population balance models for banks of cells. It then focuses on recent developments in physics-based modelling tools. This includes current efforts to model the forces of attachment and detachment at the individual event level as well as multi-event levels in individual cells and circuits. Two examples of these tools are presented. The first is DEM modelling of the mechanics of motion of bubbles in froths. The second is population balance modelling of the dynamics of flotation circuits describing how they are influenced by upstream processes (such as crushing and grinding) as well as internal process variables (such as aeration, agitation and reagent addition). Applications of each of these tools are discussed.

Jan 1, 2005

By Mining Geophysics

Modern geostatistics has eliminated much of the guess-work in ore reserve estimation, and can calculate levels of confidence for the reserve estimate. Geological modelling software has brought about a revolution in the communication of complex geo-variables to mining engineers, metallurgists, surveyors and managers. Mine planning and scheduling can now avail itself of a veritable toolbox of enabling technologies.

Jan 1, 1994

By AUIMM AUIMM

Continuous Improvement The Council of the AusIMM should expedite the introduction of a continuous professional education policy along the lines of that to be proposed to you by David Pollard today. The Education and Accreditation Committee must continually review the training needs of the next generations of mining industry professionals. It should continue to demand and encourage the creation of the schools for the training of such people. The AusIMM could even put greater onus upon university researchers to accredit university post graduate degrees.

Jan 1, 1994

By A G. Greenwood

Research into cemented rock fill at Mount Isa Mines Limited since 1992 is described. The key mechanisms controlling segregation during stope filling with cemented rock fill are described and include the gravity flow mechanism which is described in detail. Examples are provided to demonstrate these mechanisms. Comparisons are made between Mount Isa MinesÆ cemented rock fill and slurry-based cemented rock fills. Recent backfill stability modelling using a three-dimensional finite element program is described.

Jan 1, 1998

The first stage in the refining of lead blast furnace bullion is the removal of copper and is normally done as a batch process in open kettles.A number of attempts have been made to establish continuous processes operating in reverberatory type furnaces, but the growth of accretions in the furnace has always presented a serious problem.The Broken Hill Associated Smelters Pty. Ltd. (RH.A.S.) at Port Pirie have overcome this problem by constructing a reverberatory furnace and ancillary cooling system of a novel design.Although a number of mechanical and metallurgical problems still remain to be solved, it is claimed that a workable continuous copper drossing process has been established.INTRODUCTIONLead bullion emerging from the blast furnaces at Port Pirie is at a temperature of about 1100°C and contains, among other impurities, about 1 per cent of copper.The first stage of refining is the removal of this copper by a drossing operation and in the past this was done, batchwise, by allowing the bullion to cool back in 100 ton kettles.At about 700°C, copper dross begins to separate as a crust on the surface of the kettle and this separation was allowed to continue down to about 450°C when the crust was brokenup and skimmed manually using a long handled, balanced, spoon. The dross was then smelted in a reverberatory furnace to produce a saleable copper matte and separate out lead bullion, which was returned to the drossing kettles. The copper content of the drossed bullion was then further reduced by a sulphur treatment process.The drossing operations involved hard manual labour under arduous conditions and the pouring of hot bullion into...

Jan 1, 1963

By Nye P. B, Fisher N. H

At the second Empire Mining and Metallurgical Congress held in 1927, the Empire Council of Mining and Metallurgical Institutions was formed and it was proposed that the Council take steps to prepare a "Review of the Mineral Resources and Industries of the Empire." At the third congress in 1930, it was resolved that the proposal to institute the review should be submitted to the Imperial Conference held in 1930. This was done, and the Minerals Committee, of the Imperial Economic Committee compiled, an interimreport which was based on statistics of imports and exports, and did not consider resources and consumption.In 1942 the Institution of Mining and Metallurgy, London, wrote to the Empire Council and stated that it was desirable that the Council should be in a position to take part in decisions affecting the future of the mining and metallurgical industries. The Council communicated with the constituent Institutions regarding the nominations of two members then in England. Subsequently the Mining, Geological and Metallurgical ,Institute of India prepared a review of the mineral resources and industries of India and their post-war development, and the Empire Council forwarded a copy to the Australasian Institute of Mining and Metallurgy and asked if that Institute would submit a review on simjIar lines for Australia. The Australasian Institute arranged that the Australian review should be prepared by...

Jan 1, 1946