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By M Cooksey, C Goodes, G Wellwood

Light metals have great potential for application in the automotive and aerospace industries because of their excellent physical properties. The usage of aluminium, titanium and magnesium is limited by relatively high costs of production, associated energy costs and large ecological footprint. In the case of aluminium, significant improvement to the Hall-HTroult process is still achievable through advances in cell design, materials and process control. Alternative production processes, including carbothermic reduction and low temperature routes are also possible. Magnesium and titanium production are currently dominated by batch metallothermic processes and new process routes are required to develop these industries. Research at CSIRO, through the Light Metals Flagship, is currently focused on step change improvements in the production of light metals, aimed at lowering energy usage, increasing productivity and reducing the overall environmental impact. In this paper, the overall status of the existing technologies will be described, highlighting areas that are being developed around the world and at CSIRO.

Jan 1, 2006

By Y Li, B Shen, S Zhang

Jointed rock mass is often encountered in rock engineering and its stability has always been a major concern in underground engineering. To analyze the stress characteristics and their variations in jointed rocks, in this study, a new concept of sub-instability stage before rock failure is defined, and a new experimental method is used to investigate interaction between defects and intact rock of the jointed rock mass during the subinstability stage., Firstly, external characteristics of stress and failure mode of the whole jointed rock are investigated systematically by conducting uniaxial compression tests on red sandstone samples with a set of preexisting open flaws of different sizes, and the interactive damage of intact parts and defects in the subinstability stage was further studied. Secondly, rock-like material samples made of bonded plaster blocks were tested and internal data from stress sensor between the strong and weak segments were collected. The transforming processes from independent activity of the individual segment to overall interactive movement of jointed rock before the unstable failure were analysed. The test results indicated that the subinstability stage marked the beginning of interactive failure between the intact rock and defects. In the early subinstability stage, the relatively intact parts bore most of the load in a jointed rock mass, and the defects were damaged firstly which caused high strain around it. The areas of high strain increase rapidly, extending and migrating, causing damage to the intact parts. In the later sub-instability stage, the interaction effect reached its maximum, and a large number of cracks appeared in the intact rock and they propagated and coalesced. Intact parts experienced rapid failure and then the jointed rock failed. The experimental method used in this paper to identify the sub-instability stage could be used to identify failure precursors of jointed rock masses and to develop technology for disaster prevention in rock engineering. CITATION:Zhang, S, Shen, B and Li, Y, 2018. Experimental studies on interactive failure characteristics of jointed rock, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 453–461 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By Forster G, Datta P. K

Many high temperature industrial processes involve gaseous halogen-bearing environments. Essentially, these fall into three subject areas: power generation, waste incineration and especially extractive metallurgy. Fundamental to any understanding of the process chemistry and efficiency in the process technology is an adequate knowledge of background thermodynamics relating to metal-chlorine reactions. In this context, existing free energy/temperature diagrams for metal chlorides do not include many elements, in particular the so called refractory elements from Group V and Group VI of the Periodic Table, namely niobium, tantalum and vanadium, and molybdenum. This paper reports estimation and calculations of the free energy values for these chlorides. The data is discussed in the context of high temperature chlorination processes.

Jan 1, 1991

By J Vann, S Jackson, O Bertoli

Ordinary kriging and non-linear geostatistical estimators are now well accepted methods in mining grade control and mine resource estimation. Kriging is also a necessary step in the most commonly used methods of conditional simulation used in the mining industry. In both kriging and conditional simulation, the search volume or ækriging neighbourhoodÆ is defined by the user. The definition of this search can have a very significant impact on the outcome of the kriging estimate or the quality of the conditioning of a simulation. In particular, a neighbourhood that is too restrictive can result in serious conditional biases. The methodology for quantitatively assessing the suitability of a kriging neighbourhood involves some simple tests (which we call æQuantified Kriging Neighbourhood AnalysisÆ or QKNA) that are well established in the geostatistical literature. The authors argue that QKNA is a mandatory step in setting up any kriging estimate, including one used for conditioning a simulation. Kriging is commonly described as a æminimum variance estimatorÆ but this is only true when the neighbourhood is properly defined. Arbitrary decisions about searches are highly risky, because the kriging weights are directly related to the variogram model, data geometry and block/sample support involved in the kriging. The criteria to look at when evaluating a particular kriging neighbourhood are the following: the slope of the regression of the ætrueÆ block grade on the æestimatedÆ block grade; the weight of the mean for a simple kriging; the distribution of kriging weights themselves (including the proportion of negative weights); and the kriging variance. Outside of the technical geostatistical literature, there is little in the published domain to describe the nature of QKNA and no practical presentation of case examples. In this paper we attempt to redress this by setting out the calculations required for QKNA and defining some approaches to interpreting the results. Several practical worked mining case examples are also given. Finally some comments are made on using the results of QKNA to assist with block size selection, choice of discretisation and mineral resource classification decisions.

Jan 1, 2003

By J K. de Wet, G Balassone, J D. Singleton, V Arseneau

The Accha-Yanque zinc belt in southernPeru is a major zinc-lead rich metallogenic province. In the belt are comprised several non-sulfide-type occurrences, extending on the periphery of the Yauri-Apurfmac batholith (Oligocene-Miocene). Zinc mineralisation at Accha (almost fully oxidised) occurs in breccias of sedimentary and tectonic origin in the limestone of the Ferrobamba Fm (Middle to Upper Cretaceous). Non-sulfide association consists mainly of smithsonite and hemimorphite replacing both primary ore minerals and carbonate host rocks. Mn(hydr)oxides and Zn-clays (sauconite), can be locally very abundant. Differences in mineralogy of the ore and gangue minerals, as well as the composition of the host rock can have a profound impact on zinc recovery and reagent consumption, and therefore on the economic value of the deposit. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Zinc concentrates from the newer mines and from proposed developments provide both opportunities and processing challenges to the conventional roast-leach electrowin smelters. These concentrates are often characterised by low iron, elevated silica, possibly high manganese, and levels of elements such as germanium which may cause concern. In addition, environmental constraints on residue disposal are forcing significant changes to some smelter practices. Iron in concentrate, and the resulting environmental impact of residue disposal are now major questions. However, normal concentrate tariff structure provides a disincentive against smelters taking high grade concentrate and oxide fume. Processing technology to cope with these changes is reviewed, as is de-watering and materials handling of ultra-fine concentrate. Within a few years, such fine concentrates will account for up to 1 000 000 t/y of contained zinc. New processing technologies including novel transport methods, siliceous leach circuits, manganese removal cells and front-end smelting will become significant in zinc smelting.

Jan 1, 1993

By R Ashworth, S J. Hall

During trials which began in May 2005, traditional steel dump bodies for transporting iron ore on 220-tonne haul trucks at a Labrador iron ore mine were compared to a novel rubber suspended dump body. Loads were measured and compared over some 93 700 loads, representing more than 20 Mt transported. Maintenance costs and downtime were also measured over the course of the trial, which lasted nearly one year. This paper outlines the parameters and results of the trials. Parameters measured included payload and production improvements, carry-back reduction, downtime due to body maintenance, and wear on the floor of the suspended dump body. These parameters were then compared to those for conventional steel dump bodies in use at the mine, and conclusions were drawn. The resulting comparisons were significantly positive in favour of the new suspended dump bodies, confirming that each truck could haul an additional 41 000 tonnes per year, that downtime hours could be considerably reduced, and that body availability and service life can be extended through use of the suspended dump body. There was also a high level of operator acceptance of the suspended dump bodies due to less loading shock and a smoother ride.

Jan 1, 2007

By D R. Lueking

A technology involving separate unit processes for the generation and use of ferric ions for the oxidation of sulphidic minerals has been developed. The technology utilises a stand-alone automated bioreactor for ferric-ion generation (termed SAAB-FIG) and produces a low pH, ferric ion-rich leach liquor with a high oxidation potential. This leach liquor is then employed, in a separate unit process, to oxidise sulphidic minerals and regenerate ferrous iron that may subsequently be recycled to the bioreactor for the continual generation of ferric ions. The technique was successfully applied for the recovery of copper from chalcocite (Cu2S) and chalcopyrite (CuFeS2), as well as other ores and concentrates containing copper sulphide minerals. Coarse ore, ground ore and concentrates were treated with acidic solutions containing 8 to 12 (g/L) Fe(III) ions at a variety of temperatures. This process yielded over 50 per cent of the contained copper from both chalcopyrite and chalcocite samples. Maximum reaction rates and copper recoveries were found to be highly dependent upon temperature and pH and leach liquors containing bacterial cells displayed little difference in their leaching efficiency when compared to cell-free leach liquors.

Jan 1, 2000

This paper details the approach adopted to develop an integrated asset management system for a GreenfieldÆs Metallurgical Plant during a recently completed feasibility study. The proposed asset management system deals with general aspects related to metallurgical operations and includes the following:plant operation and control, human resources, security systems, stores, and maintenance management. The paper deals with the establishment of requirements for the asset management system, the interfaces required, available systems in place and cost estimations for implementation. Every effort was made to integrate the system into existing corporate installations to create an integrated and effective management tool from both a plant operation and support perspective.

Jan 1, 2002

An attempt has been made in tftis paper to review the general situation regarding the needs of the Mining and Minerals Industry for skilled and qualified personnel. Having defined the behavioural objectives of the courses of study, reference is thereafter made to the factors influencing the effective design of courses for apprentices, technicians and Technologists.

Jan 1, 1981

By Feilding C

Vitrinite of humic source (often designated as vitrinite A) is the maceral by which the rank of a coal ought to be determined. Therefore its recognition, and the precise identification of other vitrinites is essential. The majority of Australian petrologists are not differentiating between the vitrinite group macerals in maturation studies, the results of which have led to unexplained phenomena in coal characterisations and evaluation, such as 'reactive inertinites' and inaccurate predictions in petroleum source rock studies. The Callide coal has been chosen as a case study, with examples from other coals. The coal seams from the Callide Coal Measures show variation in the predominance of some macerals, indicating successions of environmental changes. The application of transmission electron microscopy (TEM) to the study of the Callide coal has enabled a better understanding of the nature and origin of some of the less understood macerals such as micrinite and vitrinite B. Two forms of vitrinite have been observed, each with a distinct reflectance range. The wood-sourced vitrinite A displays an average reflectance of 0.56 per cent, and a range of 05. - 0.7, implying a higher rank than the 0.49 per cent Ro total vitrinite reflectance recorded in previous publications. Vitrinite B is one of the most commonly-occurring macerals in the Callide coal. The lower-reflecting vitrinite B which forms bands, often several hundred microns in thickness, in TEM appears to be electron transparent lipid rich. Vitrinite B is interpreted to represent accumulations of leaves, and is believed to be a major source of hydrocarbons in Australian sedimentary basins. The Callide coal has entered the oil window, and oil has been generated from some exinite, cutinite, and resinite, as evident from the amber to light brown fluorescence of exinite and the presence of exsudatinite in cell cavities and cleats. However vitrinite B, the major potential source of oil, is seen under the microscope to be generating oil, thus placing this coal at the top of the oil window. Micrinite, the origin of which has been much debated, occurs as cell filling or infill of spaces between laminations in vitrinite B.

Jan 1, 1991

At depths greater than several kilometres in the crust, elevated temperature, confining pressure, and the presence of reactive pore fluids typically drives rapid destruction of permeability in fractured and porous rock. Ongoing deformation is required to regenerate permeability and facilitate the high fluid flux necessary to produce hydrothermal ore systems. A dominant influence on the evolution of fluid pathways in hydrothermal systems is provided by stress states, fluid pressures and reactions that drive permeability enhancement and compete with permeability destruction processes (Cox, Braun and Knackstedt, 2001). An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

The energy crisis and the general increase in fuel prices have changed the position of coal in the world. Countries need to review their policies on coal, depending on available reserves and their accessibility. On the demand side, a distinction should be made between the steel industry's specific demand for coking coal and the needs of power stations where coal is used in competition with other sources of energy. Coal consumption in these two sectors is expected to increase considerably over the foreseable future. Some countries have sufficient coal of their own to meet this increased demand but others will have to rely on imports. As a result, the tonnage of coal transported by sea may double by 1985. The coal industry lacks flexibility. The opening of new mines and the construction of a transport system to ship the coal takes time. This time-lag, coupled with the enormous expenditure involved, makes long-term contracts between producers and consumers essential.

Jan 1, 1975

By F Minz, P Lamberg, A Mwanga, C Lund, C Wanhainen, M Amiri Parian, J Rosenkranz

A geometallurgical model is currently built in two different ways. The first and the most common way relies on geometallurgical testing, where a large number of samples are analysed for metallurgical response using small-scale laboratory tests, eg Davis tube testing. The second, mineralogical approach focuses on collecting mineralogical information over the orebody and building the metallurgical model based on mineralogy. At Lules University of Technology, Sweden, the latter method has been adopted and taken further in four ongoing PhD studies. The geological model gives modal composition by the help of element-to-mineral conversion and Rietveld X-ray diffraction. Texturally, the orebody is divided into different archetypes, and liberation measurements for each of them are carried out in processing fineness using IncaMineral, a SEM-based technique. The grindability and liberation spectrum of any given geological unit (sample, ore block, domain) are extrapolated from the archetypes. The process model is taken into a liberation level by mass balancing selected metallurgical tests using the particle tracking technique. The approach is general and can be applied to any type of ores. Examples of ongoing studies on iron and massive sulfide ores are given.CITATION:Lamberg, P, Rosenkranz, J, Wanhainen, C, Lund, C, Minz, F, Mwanga, A and Amiri Parian, M, 2013. Building a geometallurgical model in iron ores using a mineralogical approach with liberation data, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 317-324 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

The introduction of gravimetric sampling of respirable dust in the mining industry ne- cessitated the standardisation of techniques. The paper reviews the legislation con- trolling respirable dust monitoring for risk assessment purposes, it discusses the actions taken to introduce gravimetric sampling in collieries and it summarises the proposed guidelines. In conclusion, some of the results of dust surveys conducted in accordance with the proposed strategy are discussed.

Jan 1, 1988

By Matthew I. G, Hall P. G

The Selective Precipitation (Basics) Process is a means of controlling impurities such as the ions of Mn, Mg, and Cl as well as sulphate and water, in an electrolytic zinc plant circuit. This is achieved by precipita- ting zinc selectively as a basic zinc sulphate from a portion of impure circuit solution. The impurities remain in the solution, which can be discarded, while the zinc, substantially free of impurities, is returned to the main circuit by using the precipitate as a neutral- ising reagent. A description of the process and its development to a full scale operating plant at the Risdon Works of the Electrolytic Zinc Company of Australasia Limited is Presented.

Jan 1, 1977

By E Nettleton, A Melkumyan

Identification of geology and mineralogy in situ on the mine face is essential if mining processes are to be automated for tasks such as exploration, grading and reconciliation. Hyperspectral data acquired from field based platforms are ideally suited to these tasks, and are set to revolutionise the automated mining industry. Changing conditions of solar illumination introduces variation into the hyperspectral signal, which is unrelated to geology, complicating analysis of data. Thus, algorithms must be able to deal with changing illumination conditions and operate in a consistent and probabilistic framework, which is a prerequisite for data fusion with other sensors. To produce accurate classification maps of geology, algorithms must be developed that are effective under different conditions of illumination.The efficacy of three algorithms to classify hyperspectral data for geology mapping on vertical mine faces was assessed. These algorithms are the spectral angle mapper (SAM), and two machine learning methods operating within a fully probabilistic Gaussian process (GP) framework û the squared exponential (SE) and the observation angle dependent (OAD) covariance functions (kernel). Two experiments were done to assess the classification performances. The first determined the performance of the algorithms by classifying hyperspectral data of known rock samples acquired using a field spectrometer. The GP-based methods had a similar performance, with average accuracies and F-scores of 97 and 88 per cent (GP-OAD) and 95 and 81 per cent (GP-SE), respectively. Average accuracies and F-scores for SAM were significantly smaller (80 and 40 per cent respectively). The algorithms were then applied to hyperspectral imagery acquired from a vertical mine face at different times of the day, under very different conditions of illumination. In contrast with experiment 1, SAM and GP-OAD gave results which were superior to GP-SE and were entirely consistent with geology mapped in the field. Compared with SAM, GP-OAD was less sensitive to the effects of shadow and produced classified images that were less noisy. The GP-SE method failed to delineate even gross changes in geology on the mine face. These results show conclusively that in order to use independent training data (spectral library) to classify imagery acquired under a different set of conditions, algorithms must take into account variability in incident illumination. Measures based on spectral distance are inferior to those based on spectral angle.The OAD kernel within the GP framework (GP-OAD) is superior to the other two methods because:it provides a probabilistic framework;it is insensitive to variability in illumination within and between imagery acquired under different conditions; andit can identify and map geological zones on a vertical mine face using an independent spectral library, without a priori knowledge.

Sep 26, 2011

By D A. Deglon

Solids suspension is important in the design and operation of mechanical flotation cells, and is a necessary precondition to particle collection. Most of the fundamental hydrodynamic research that incorporates some aspect of solids suspension was done by Arbiter, Harris, and co-workers, or Schubert and co-workers. However, a need for research into solids suspension in mechanical flotation cells exists, since very little has been done since the late 1980s; a time that also coincides with the advent of round mechanical flotation cells and the subsequent dramatic increases in maximum flotation cell sizes. In this work, concentration profiles and critical impeller speeds, Njs, were measured in a 0.124 m3, round cell fitted with a 0.150 m, Bateman impeller mechanism. Two solids size fractions (75 - 106 and 150 - 250 ¦m) were tested, in ungassed and gassed conditions (JG = 0, 1 cm/s) and at various impeller speeds (300 - 900 rpm). The effectiveness of solids suspension was quantified in three ways in terms of extent of off-bottom solids suspension, suspension height (extent of solids distribution), and variation within the solids distribution, which together present a complete quantitative picture of solids suspension and distribution within the cell. Consistent trends were found when these effectiveness criteria were considered against relative impeller speed, in terms of percentage of critical impeller speed, N/Njs. Off-bottom solids suspension is complete at or above 100 per cent of Njs, with significant sedimentation occurring as the impeller speed drops below 60 per cent of Njs. Suspension heights consistently reached a level equivalent to 90 per cent of the tank diameter at the critical impeller speed, and dropped off significantly as N/Njs dropped below 60 per cent. The variation in the solids concentrations within the sampled profiles showed consistent trends in two-phase but not under three-phase conditions. The paper concludes that the critical impeller speed, Njs, commonly used in the design and operation of standard stirred tanks, is a very useful solids suspension benchmark for describing all aspects of solids suspension in mechanical flotation cells and should be correlated to system conditions.

Jan 1, 2005

By Y, Li Jianxiong, Hu Hua, Gu Desheng

After having briefed the technical and economical advantages of continuous mass mining in underground metal mines, the authors discuss the four stages of research and development of continuous mass mining in China. The four stages are: vibrating ore drawing in a stope, continuous mass mining in a stope continuous mass mining without rib pillars in an area and continuous mass mining in whole mine. The authors briefly review the research achievements of the first and the second stage; Combining the key national research project of the æNinth Five Year PlanÆ ù æThe experiment and research of continuous mass mining without rib pillarÆ, the authors introduce in detail the technological condition of mining, the design ideas of continuous mass mining, the design scheme of mining, the technology of mining. the equipment of mass mining, the chief research achievements and so on. The success of research of continuous mass mining without rib pillar indicates the arrival of the third stage of research. The introduction of continuous mass mining will promote the technology revolution of mining in China remarkably. The authors also point out that the development direction of continuous mass mining of the 21 century is continuous mass mining in whole mine, which is the fourth stage of research.

Jan 1, 2000

By Hagan T. N, Tucker A. J

The Cumnock Open Cut Mine (COCM) is located in the Hunter coalfield in New South Wales. Five coal seams are being mined, mostly by drilling and blasting, loaders and excavators, and trucks. The annual production of coal is 1.3 million tonnes. Overburden and interburdens consist mostly of siltstones and medium to thickly bedded sandstones. The strata dip to the south-east at approximately four degrees. There are no major faults in the rock mass.

Jan 1, 1995