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By Szwedzicki T

Uniaxial testing was performed on model pillars to determine the effect of width to height ratio on pillar and surrounding rock mass stability. Samples were modelled in a shape similar to that of dumbbell weights, with the centre representing

Jan 1, 1994

By Hunt MS

A major diamond mining operation in South Africa is faced with the unique problem of recovering usable water from the fine tailings stream. The kimberlite ore hoisted is washed prior to crushing in order to remove adhered fine clay particles. These particles form a colloidally stable suspension from which it has not been possible to recover clear recycle water. Research has been conducted on this problem for more than 20 years and it is only recently that a breakthrough has been achieved. This paper describes the work done to gain an understanding of the suspension stability and which subsequently led to the testing of a process at pilot-plant Scale.

Jan 1, 1988

Magnesium-rich olivine is used as an additive in LKABÆs iron ore pellets in order to improve the high-temperature properties of the finished products. Olivine is only added to the pellets that are manufactured for ironmaking in the blast furnace process. The olivine comes from Minelco/LKABÆs mine at Seqi in Greenland. This dunite complex of Archean age contains about 95 - 98 per cent olivine. The grain size is typically 1 - 3 mm but much larger euhedral olivine crystals are common in the porphyritic type. The serpentinisation is absent or weak. The most common minor minerals are chromite, chlorite, talc, phlogopite, amphibole and pyroxene. The crushed olivine is transported to LKABÆs pelletising plants in Northern Sweden. After grinding, small amounts of olivine are mixed with the magnetite concentrate. The concentrate is rolled into green balls, about 10 - 14 mm in diameter. The moist green balls are transferred into the pelletising machine where the maximum temperature is about 1250¦C. The residence time in the pelletising machine is about one hour. Olivine is used in order to get pellets with better high-temperature properties. This paper deals with the olivine alteration during the pelletising process and the behaviour of magnesium following the decomposition of magnetite. The reactions are quite complex in the pellets because the physico-chemical conditions vary considerably in the process from one process step to another, and in the pellet bed from the top to the bottom. Some olivine particles in the finished product show very slight alteration, some particles are completely decomposed. The formation of the iron-rich coronas around the olivine particles is the most typical alteration. In the finished pellets the magnesium is mainly distributed between the following phases: unaltered olivine, coronas, Mg/Fe-ferrite and silicate slag.

Jan 1, 2008

By T J. Beardsmore, N Wyche, D Flint, T J. Griffin

Western Australia (WA) is currently the world’s largest iron ore producer, and mining of its huge reserves and resources of iron ore has become a critical part of the state’s economy and regional development. Iron ore exports from WA have reached 760 Mt/a, corresponding to shipping more than one Mt per turn-of-the-tide from the state’s ports. The iron ore sector dominates all commodities produced in WA, and in 2016 accounted for 77 per cent of the state’s royalty receipts, 56 per cent of mineral and petroleum exports (by value) and 50 per cent of mining industry employment. Expenditure on exploration for iron ore (including that for resource estimation and conversion to ore reserves) has declined markedly, from its record peak of $1100 M in 2012 to $280 M in 2016, placing it second after gold. Foreign investment has been a key element underpinning development of the iron ore industry from the 1960s until today, and will likely continue to be so into the future.CITATION:Flint, D, Wyche, N, Beardsmore, T J and Griffin, T J, 2017. The importance of iron ore to Western Australia’s economy, in Proceedings Iron Ore 2017, pp 7–12 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Ward C. W

Conventional polygonal and block modelling techniques inadequately represent the grade-thickness distribution of some narrow shear and stratabound gold deposits. The polygonal influence of high-grade drill intercepts can result in overestimates of resource tonnages at high-grade cut-offs. Although block modelling methods provide grade smoothing and a better representation of structural continuity, the technique can lack precise definition of ore width. An alternative method known as Spatial Object Modelling (SOM) has been developed on MineMap software to overcome some of these modelling issues. This method does not rely on a uniform cell size and allows grade smoothing between resource intercepts in three-dimensional space. The SOM technique creates grade-thickness bars on regular, user-defined spacings which allow easy visual comparison of raw intercept data to the interpolated model. Model cell values are readily transformed into isopachs, isopleths and resource perimeters for reporting and mine planning purposes.

Jan 1, 1997

Ulan Coal Mines Limited operates an underground and open cut mine near Mudgee in the Central West of NSW. The mines are part of a Joint Venture managed by Exxon Coal and Minerals Australia Limited (ECMAL). Currently all the mines output of over five million tonnes per annum is sold into the export market predominantly as a steaming product.

Jan 1, 1993

By S La Brooy, C Fountain

Throughout its history the mining industry has focused on the highest-grade deposits sited in the most convenient locations. The burgeoning global population and higher standards of living not only increase the demand for mineral products but also make it harder to mine and process them. The future will include the development of lower-grade, more complex orebodies, and orebodies in difficult locations. The industry will be expected to provide for humanityÆs needs while reducing its environmental footprint and maintaining profitability. This paper reviews some of the likely adaptations in mineral processing that will occur over the next 20 years. The challenges inherent in adapting to lower grade and more complex materials might be exacerbated by such factors as the availability of water and low-cost energy. In underground mining, higher energy costs are likely to foster further developments in underground preconcentration, especially for ores that can be upgraded at relatively coarse sizes. The adoption of underground crushing could also render material amenable to semi-dry preconcentration options such as might be achieved by the rotary classifier developed by CSIRO and being commercialised by RCR Tomlinson, or more modern versions of the hand-sorting of ore that use sensors based on colour or other suitable rock properties. The cement industry and some gold roasters have used the alternative of dry grinding and classification, which might also have a part to play in dry processing. There is also likely to be increased interest in options such as in situ leaching that further minimise the surface disturbance. Underground operations will have to balance the energy savings from reducing the amount of material brought to the surface and reduced surface disturbance against the practical limitations of installing and maintaining processing equipment underground. On the other hand, surface disturbance and energy issues in open cut operations will be balanced by potentially lower mining costs and higher overall recovery from the deposit.

Jan 1, 2008

By Lorenzen L

In South Africa, as in many other countries, the young engineering graduate is promoted quite soon to a management position where he uses less technical skills and more people-oriented skills. In the standard undergraduate curriculum for engineering, little attention is paid to the non-technical issues of the profession. An undergraduate course in management techniques cannot be a substitute for a MBA or Masters degree in engineering management, but can at least create an awareness of the practical problems facing the engineering manager. The aim of this paper is to provide an outline of such a course structure at the University of Stellenbosch. A survey is also presented on management training in the South African and Australian mineral industries. Feedback from students and graduates indicates that the fresh graduate does not fully appreciate the value of such a course until he/she achieves a position of responsibility after two or three years. Nevertheless, the management course appears to be successful in widening the perspectives of the engineer. As explained frequently in management journals, the technically oriented person (the engineer) has a convergent thought pattern, which could be in conflict with the more divergent thought pattern of the top, personnel or marketing manager. It becomes increasingly imperative for the young minerals engineer to be externally oriented instead of the traditional internal focus of engineering. The engineer should not only be aware of environmental issues in the technical design and operation of plants, but should also understand the inter-relationship between public relations, political pressures and environmental perceptions vis-d-vis technical facts.

Jan 1, 1993

By Wilkinson LR

The object of this paper is to present a brief overview of applications of radioisotopes in mineral processing. The emphasis is towards on-line applications, and is to present the broad picture rather than become involved in the details of particular applications. For a more detailed and comprehensive coverage, the reader is referred to the International Atomic Energy Agency International Symposium on Nuclear Techniques in Exploration, Extraction and Pro- cessing of Mineral Resources, held in Vienna 7-11 March, 1977. Because of space limitations here, we have inmost cases restricted coverage to those applications of radioisotopes within the direct experience of Amdel and Australian research bodies. Radioisotopes spontaneously emit energy in tiie Form of a and S particles, and electromag- netic radiation. The electromagnetic radiation is generally referred to as y-radiation when it originates from the nucleus, and X-radiation when originating from the electrons orbiting the nucleus. X-ray and y-ray energies overlap, with X-rays extending from a few electron volts (%') up to about 100 keV. Gamma rays in the useful energy range extend from a few keV up to .feV.

Jan 1, 1978

A brief review of the problems in ventilating and cooling deep and hot Australian mines is presented. An overview is given on the development of the controlled partial recirculation concept. The main part of this paper describes the first majo

Jan 1, 1994

I am very pleased to be here at this seminar on carbon-in-pulp (CIP) technology for the extraction of gold as I am always interested to hear about any new development in any aspect of gold ore processing. We can expect to learn a great deal from the papers to be presented over the next few days. It is not my purpose to give a detailed description of the CIP process nor to give a complete historical review. However, in this opening address it was thought appropriate that I should mention some historical features and some technical factors to set the scene for subsequent papers. HISTORICAL NOTE Table 1 shows some interesting dates of the use of carbon in gold metallurgy in Australia. Mount Morgan used carbon after chlorination TABLE I Carbon precipitation in Australia 1891 Mount Morgan 1917 Yuanmi mine (Edmunds) 1934 Sons of Gwalia (Edquist) 1975-1980 Various pilot plants and small companies 1980- Various large and small plants

Jan 1, 1982

The hoisting system at the Newcrest Telfer mine is designed for a final duty of 7.35 million tonnes per annum at a hoisting distance of 1450 m. In terms of hoisting capacity (t/h) times hoisting distance it is one of the largest friction hoist installations. Initially, the hoist will be equipped for hoisting 6.5 Mtpa from 1100 m depth. This new drive technology is now well proven by ABB for mine hoist applications with the first installation in commercial operation since July 2001. To date 17 systems for medium voltage drives and another five for low voltage drives have been purchased from ABB for mine hoists. This paper will also deal with skip design and powerful data loggers with diagnostics for local and remote monitoring that are installed in the Telfer mine hoist.

Jan 1, 2005

The paper will review the marked upsurge in the installation of new continuous metal coating lines, both hot dip and electrodeposition. Although some of this new capacity has been replacement for obsolete facilities or directed at traditional markets, eg building products, consumer durables etc, by far the major portion is targeted at the automotive industry. The reasons for the rapid growth of coated automobile panels are discussed. A comparison of the installed capacity with projections for this market indicate that a severe over-supply situation has arisen. Many coatings are now available for the automotive industry, each with their own strengths and weaknesses, but none as yet wholly satisfactory. Coating development has mainly been cost driven. This favours hot dipped coatings, providing surface quality and pressing problems can be overcome. The high cost per unit thickness of electrodeposited coatings has also seen pure zinc coatings being replaced by thinner, more corrosion resistant alloy coatings such as zinc-nickel and zinc-iron. Recently resin overlays have been introduced to improve the performance of electrodeposited coatings. Developments in coatings for the more traditional markets will be described. The fastest growing market in the last decade has been prepainted product for the building industry. This has led to the installation of extra painting capacity and again it appears an excess capacity situation has occurred. Over the same period the traditional zinc coatings have continued to lose market share to the zinc/aluminium alloy coatings, Galvalume and Galfan. These have been joined recently by '1'aiyo Crack-Free which has been taken up by some metal coaters. Galvalume is now widely accepted as being the best available coating for unpainted applications. It is also suggested that 'spin-off' coatings from automotive developments might find a niche in the consumer durable market. The end users of coated products, particularly the automotive industry, have demanded improvements in quality, such as surface smoothness, formability, etc. At the same time the new coating lines have to process wider strip and run at faster speeds. To reconcile these somewhat incompatible needs has required numerous process improvements, many of which need in-line instrumentation and computer control. The more important of these changes are discussed briefly. Finally the paper will describe the recent developments which have occurred in continuous galvanising in Australia and put them into context with the rest of the world.

Jan 1, 1993

By Myers I. A, Peters S. G, Bultitude R. J, Dowling K

Gold-quartz and antimony-gold-quartz veins in the Hodgkinson Province are hosted by subgreenschist to greenschist facies metasediments and show no spatial association with granitic rocks. They commonly parallel axial plane foliations or occur in brittle to brittle-ductile shear zones. Detailed mapping in the Hodgkinson goldfield indicates that vein systems are isolated in distinct structural and lithologic domains by post-mineralization faulting. Gold-quartz and antimony-gold-quartz veins have distinctive mesoscopic textures characteristic of the mesothermal vein environment. Some of the antimony-gold-quartz veins are located on domain boundaries which truncate the gold mineralization. In. some areas, tin and tungsten-tin mineralization which are spatially related to Late Palaeozoic granitoids appear to postdate the gold-quartz and antimony-gold-quartz mineralization.Oxygen and hydrogen isotopic studies of vein and alteration assemblages associated with these diverse ores provide constraints on fluid sources and have implications for the origin of mesothermal gold mineralization. The available isotopic data are consistent with a dominantly magmatic source for tin and tungsten-tin mineralization although there is evidence of a late-stage meteoric component in some tin-mineralizing systems. Although a distal magmatic contribution cannot be entirely discounted, the gold-quartz and antimony-gold-quartz veins were probably deposited from deeply

Jan 1, 1990

By Anylmore M, Walker A, Fletcher A

Roasting of sulphide and sulph-arsenide gold ores produces unwanted emission of sulphur and arsenic oxides, and a less than complete recovery of gold. Pyrite loses sulphur and arsenopyrite loses arsenic at a useful rate at temperatures of 600¦C and above in an inert atmosphere. Sulphur and arsenic driven off can be condensed before entering the atmosphere. During the process, solid-solution gold redistributes itself on internal surfaces of the resulting iron sulphide. Two subsequent processing options may be used; direct cyanidation of the porous sulphide resulting from the anoxic pyrolysis, or a second-stage roast to oxidise the remaining iron sulphide. The first option may be viable under certain conditions of pyrolysis. The two-stage option has an environmental advantage over the traditional roast because it reduces oxide vapour emissions by 50 per cent. The second stage may provide nearly enough energy to sustain the entire process.

Jan 1, 1992

Degussa's PAL-system (peroxide assisted leach) has been proven to be more economical than the conventional cyanidation technique. Significant in- creases in the gold recovery have been reported, accompanied by savings in cyanide. Accelerated extraction kinetics and modified reagent demands necessitate a redesign of the conventional cyanidation plant. The South African Osprey Mine is presented as an example of a successful PAL-application. Based on the plant and laboratory data it is shown that the redesign of the flowsheet can be an important factor for the effectiveness of a metallurgical plant. In the case of the Osprey Mine, the PAL-technology all ows a modification of the current preoxidation-ClPcircuit to two separate CIL-plants to treat run-of-mine ore and old tailings dumps. A doubling of the throughput is possible without enlargement of the plant. This innovation in the field of gold extraction, the combination of the PAL-process with a redesign of the metallurgical plant, can be considered as a basis for a more profitable gold mine.

Jan 1, 1991

By Rigby D, Gould K. W, Hart G. H

The variation in chemical and isotopic composition of hydrocarbon gases generated from humic source rocks in the Cooper Basin, the orth West Shelf, the agoorin oil shale deposit. ollinsville and the southern Sydney Basin is reviewed, discussed and interpreted.The primary composition of gases generated in and released from such source rocks appears to be very largely controlled by the degree of dispersion of the organic material. For example in eoaly shales, where the degree of dispersion may be high, products as generated may escape into surrounding inorganic structures where further maturational reactions may proceed. On the other hand, when the organic materials occur in massive form, as in coal seams, the hydrocarbons generated tend to be retained within the coal. Further cracking to the stage of methane generation is usually required before release of hydrocarbon products is significant.Secondary factors of importance in determining seam gas composition in the Bowen (Collinsville) and southern Sydney Basins are the invasion of coal measures by carbon dioxide from external magmatic sources and/or the vertical diffusion and loss from the surface ofgases generated at depth.Isotopic measurements of gas composition have been particularly valuable in determining the origins and histories of the gases examined, in demonstrating when gases are of mixed origins and in the prediction of gas quality in exploration.

Jan 1, 1985

Blasting, particularly bench blasting, uses finite length cylinders of explosive close to two free faces. The rock to be blasted is usually intersected by a complex 3-D system of joints. To fully simulate a blast, a 3-D dynamic model is required. It is shown that the static stress distribution around a long cylinder can be reproduced by superposing the static stress distribution of a suitable chain of spheres. Thus, the dynamic results for individual spheres given by Favreau (1969) can now be substituted for the static results to give a dynamic model of the stress distribution around a long cylinder. Comparison of measured and computed waveforms show that the measured waveforms are much more attenuated and dispersed than expected. The consequences for explosive evaluation and design are Discussed.

Jan 1, 1990

By R Lloyd

Coal Services (Health and Safety Trust) funded ARRB Transport Research Ltd to investigate fatigue and performance of truck drivers over consecutive shifts. The main questions were to assess: What is the most important contributor to acute fatigue in mining? Is it length of shift (eg eight hours versus 12 hours) or is it time of day (eg circadian effects)? What is the limit of successive day or night shifts before chronic fatigue affects operator performance in open cut mines? The project methodology included utilising ARRB Fatigue Monitoring Devices (forced-choice stimulus reaction) in eight haul trucks, testing 24 subjects over several weeks. Each subject filled in a Fatigue Risk Questionnaire on lifestyle and health. Operators worked a 14-night, one day off, 13-day roster of 12-hour shifts in a fly-in/fly-out operation with excellent opportunities for restorative sleep between shifts. A total of 3500 hours of real-time data was collected, representing the first set of objective, real-time driver performance data for Australian mining. The data showed that for a single night of driving haul trucks, there appears to be no effect on operator fatigue from the amount of time on task (for the 12 hours). In fact performance was worse through the first eight hours than the last four. The circadian influence had a stronger affect than working more than eight hours. Of the 14 nights worked at the site, nights 13, 14, seven and two respectively, were the worst. This presents a conundrum for policy makers who may like to place caps on working hours or rosters in the hope that it will alleviate the fatigue issue. It will not. The major finding within this study is the combined influence of circadian rhythms (human body clock) and individual variability on performance. The lifestyle habits and the health of individuals have a profound effect on operator performance as shown by the strong positive correlation between high fatigue risk scores from the Fatigue Risk Questionnaire and poor performance. An individualistic approach would appear to have the best chance of reducing high potential incidents due to fatigue through successive nightshifts.

Jan 1, 2005

By Daniels E. J, Morgan W. A

In response to the increase in consumption of galvanised steel for automobiles in the last decade and the problems associated with remelting larger quantities of galvanised steel scrap, a process is being developed to separate and recover the steel and zinc from galvanised ferrous scrap. The zinc is dissolved from the scrap in hot caustic using anodic assistance and is recovered electrolytically as dendritic powder. The dezinced ferrous scrap is rinsed and used directly. The process is effective for zinc, lead, and aluminum removal on loose and baled scrap and on all types of galvanised steel. The process has been pilot tested for batch treatment of 900 tonnes of mostly baled scrap. A pilot plant to treat continuously loose scrap, with a design capacity of 48 000 tonnes annually, has been in operation in East Chicago, Indiana since early in 1993. The first 450 t of scrap degalvanised in the pilot plant have residual zinc below 0.01 per cent and sodium dragout below 0.01 per cent. Use of degalvanised steel scrap decreases raw materials, environmental compliance costs, and opportunity costs to steel- and iron-makers. Availability of clean degalvanised scrap may enable integrated steel producers to recycle furnace dusts to the sinter plant and EAF shops to produce flat products without the use of high quality scrap alternatives such as DRI, pig iron, or iron carbide. Recycling the components of galvanised steel scrap saves primary energy, decreases zinc imports, and adds value to the scrap. The quantities of zinc available by the year 2000 from prompt and obsolete automotive scrap will approach 25 per cent of zinc consumed in the major automotive production centres of the world. Zinc recycling from galvanised steel scrap, either before or after scrap melting, will have to be Implemented.

Jan 1, 1993