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By W. M. Peirce

COAL'S importance in the metallurgy of zinc may be gauged by the fact that approximately a million and a half tons is so employed annually in the United States. This brief paper will show in what way the various steps in the treatment of zinc ores utilize this fuel, either in its primary form or as coke or gas, and to what extent. The first step in zinc metallurgy that requires the use of fuel is roasting the sulphide ore, which is the type of ore in which zinc commonly occurs. Since the roasting is nearly or completely autogenous, however, this use of fuel is too minor to warrant further attention. Concentration of zinc ores is usually carried out by conventional milling methods, but a pyrometallurgical method, the Waelz process, is used to concentrate certain low-grade ores, and to recover the zinc content of certain residues in concentrate form. The Waelz process uses a continuous rotary kiln in which a mixture of coal and zinc-bearing material is heated to a

Jan 1, 1948

By K H. Esbensen

The Theory of Sampling (TOS) has made remarkable strides and has witnessed a suite of achievements over its ~65-year history; especially in the last 15 years, since organised work began for the erstwhile fragmented sampling community (2003). Theory and practice have been very well exposed and disseminated, as witnessed in the successful series of the World Conference on Sampling and Blending (WCSB) events and other dedicated sampling and mining conferences in Australia and South Africa. At this WCSB8 occasion we fittingly devote a section of our conference to celebrate the life and monumental achievement of Pierre Gy, the originator of the Theory of Sampling; a special issue of TOS Forum was recently published to the same purpose. But TOS is most emphatically not a finished work.Here I try to look into the future with a personal view: TOS – what’s next? Commensurate with this objective there is offered some out-of-the-box thinking. The purpose is to try to zoom in on probable additional future aspects of TOS and its application compared to the first 15 years of our common journey. There are bound to be lacunae here-and-there across the vast application horizon delineated, which is as it should be, as this lecture is meant to initiate a broad(er) debate – and readers may agree with all, parts, or none of the topics presented. All is well that furthers this debate.CITATION:Esbensen, K H, 2017. Theory of Sampling – what’s next?, in Proceedings Eighth World Conference on Sampling and Blending , pp 29–38 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By M. C. Ruiz, M. E. Godoy, J. B. Rivarola, M. W. Ojeda

The amount of Pd recovered from an exhausted olefin hydrogenation catalyst was found to depend on mixing technique, particle size, carbon percentage, chlorine flow, reaction time and temperature. Pd extraction was total when a sample in the 125-175 micrometre particle size range was chlorinated for 60 min at 723 K with 20 cm3 Cl2/min, for 60 min at 748 K with 30 cm3 Cl2/min and for 30 min at 773 K with 30 cm3 Cl2/min. No C addition was needed; the initial C content of the catalyst was sufficient for total recovery. Pd extraction was also affected by heat treatment in different atmospheres before chlorination. Treatment with O2, N2 and N2 with traces of O2 led to different degrees of oxidation of C and permitted the formation of oxidised Pd species. Thermal pretreatment in N2 with traces of O2 was most conducive to Pd extraction

Jun 21, 1905

By A. W. Khair

This paper deals with the analysis of pillar failure in a room and pillar mining operation of a deep underground coal mine. The incident here involved the failure of more than 100 pillars. The mechanism of pillar failure (bump/squeeze) has been studied in detail. The analysis consists of inmine eyewitness observations, laboratory experiments and analytical study of the pillar failure area using finite element technique. Results indicated that the mechanical properties of coal, roof and floor, geologic condition, and the method of operation have affected the mode of pillar failure. Hard roof and floor prevented roof caving and floor heaving in the gob area creating an inhomgeneous stress field on the pillar. This condition developed a yield zone and a core zone in the pillar. Progressive increase of vertical stress further increased the yield zone of the pillar and reduced the core pillar leading to a total squeeze of the pillar. However, the analysis indicated that the pillars were liable to bump provided any sudden shift of load occurred on the core pillar due to some dynamic shock imparted by a local failure of the immediate roof (slickenslided area) or during splitting.

Jan 1, 1986

By Bibby P. A, Leupen R. A

A 24,300 tonnes per year state of the art Silicon smelter is being constructed for Barrack Silicon Pty Ltd at Kemerton, 20 kilometres north of the City of Bunbury in Western Australia. The plant is designed for the reduction of high purity quartzite lump to metallic silicon in two 27MVa Demag submerged arc electric furnaces. The primary reductant, a high purity charcoal, will be manufactured at the plant from locally sourced jarrah wood waste (Eucalyptus Marginata). Commercial silicon production is scheduled to commence in October 1989. Keywords: Silicon, Smelter, Quartzite, Furnace, Charcoal, Jarrah, Wood, Eucalyptus Marginata.

Jan 1, 1989

By R. L. Guerguerian

Nowadays, most grinding mills driven by a wrap-around ring motor are operating successfully. Some of the earlier problems could be attributed to the lateral stiffness and stability of their bearings. As a result, modifications to the bearings included the rearrangement of the shoes, or the addition of more shoes, closer to the horizontal centerline. This technical paper reports a study of the effects of bearings on the lateral stiffness of grinding mills driven by a wrap-around ring motor. The discussions cover the design of the four shoe trunnion bearings and examine the effects of the angular location of the shoes.

Jan 1, 2000

By S Chew, A Bennett, N Di Giorgio, B Osborne

After relining one of two blast furnaces and enlarging its sinter plant in 2009, BlueScope radically restructured its Port Kembla steelworks operation in 2011, shutting a blast furnace and halving its total production. This drastic move in response to unprecedented raw material prices relative to achievable steel prices was like that of many integrated steelmakers worldwide facing similar challenges. The 2011 restructure also saw major changes in the amount and type of iron ores and ferrous burdens purchased, and a fundamental reappraising of ‘value’ in iron ores. This paper outlines the changes to raw materials purchases from 2011 to 2017, how BlueScope has responded to the changes in pricing and raw materials quality, the effect on the sintering and blast furnace processes at Port Kembla resulting from higher gangue content, some of the broad technical and economic challenges faced by steelmakers confronted with lower quality iron ores and how BlueScope is meeting those challenges.CITATION:Di Giorgio, N, Bennett, A, Osborne, B and Chew, S, 2017. Recent Port Kembla experience with iron ore use – sintering and blast furnace, in Proceedings Iron Ore 2017, pp 25–30 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By O. A. Carson

Introduction Although the equilibrium conditions of the copper-tin alloys have been the subject of a ?great amount of research, the equilibrium diagram is still in doubt. The first systematic investigation of the series was made in 1894 by Le Chatelier, who published a freezing-point curve. In 1895, Roberts-Austen and Stansfield published the complete liquidus and partial solidus curves, which they modified somewhat in 1897. Their liquidus as given in 1897 is essentially that accepted today (Figure 3). Haycock and Neville also published a liquid us curve in 1897. In 1898, William Campbell published a series of micrographs showing the changes in microstructure which accompanied the thermal changes of Stansfield? s diagram. The classic work on the bronze series was published by Heycock and Neville in 1903. Their diagram was based on both thermal and microscopic evidence, and is the first for this series of alloys which can be considered nearly complete. Further, it was the first bronze diagram in which any attempt was made to apply the phase rule in the interpretation of the thermal and microscopic results. That portion of Heycock and Neville's diagram covered by the present work is reproduced in Figure 7.

Jan 1, 1929

By N. Johnson, J. Quinteros

With the general trend across all commodities towards the treatment of lower grade ores, it is becoming increasingly important to develop efficient protocols for comprehensive mineralogical characterisation to allow the development of the most appropriate strategies for processing an ore. In the case of silver, there are more than 200 known silver bearing minerals which can make it challenging to identify them. Knowledge of the deportment of silver within an ore is one of the factors used to determine an appropriate processing strategy. Automated SEM-based tools are commonly used for mineralogical characterisation but the low-grade together with the large number of minerals that are potential hosts for silver means that often, complementary analytical tools must be used in order to properly account for the silver. The work presented in this paper is a demonstration of the approach that should be taken when identifying the deportment of silver in complex ores. Three complex, low-grade silver ores were characterised using the approach. The insights from the mineralogical characterisation were then used to inform the metallurgical testing that was undertaken. The results from the batch flotation testing clearly demonstrate the importance of understanding the mineralogy in order to select the most appropriate metallurgical processes.

Jan 1, 2014

By CORA ROELOFS

While the COVID-19 pandemic has dominated the headlines, another epidemic in the United States has continued apace — the opioid epidemic. Half a million opioid overdose deaths have occurred in the United States since 1999, when the opioid epidemic began. The causes of the epidemic include the rise in prescriptions for opioid pain medications, including for work-related pain. Miners and other occupations identified as physically demanding and at higher injury risk have been found to be at increased risk for opioid overdose [1]. However, awareness of the risk factors that might lead to opioid use, the potential hazards associated with their use, and resources to prevent addiction and death can allow miners to make choices that can reduce these risks.

By P. P. Sinha, D. N. Bhatia, B. R. Ghosh, R. K. Gupta

Medium carbon, low alloy, high-strength steels containing Ni, Cr, and Mo are used for the fabrication of various types of high-strength fasteners required for launch vehicle structures. Cold heading properties and response to hardening and tempering are the essential requirements of the material for fabrication and application, respectively. Combining these two requirements is essentially warranted in high-strength fastener-grade steels. Cold heading properties require ductility, which can be achieved through spheroidizing treatments. In the absence of a suitable spheroidizing cycle for medium carbon 3.8 Ni, 1.8 Cr, 0.3 Mo steel, experiments were carried out with a theoretical understanding of the alloy system. This paper presents the experiments and results obtained after a spheroidizing treatment, which was carried out to optimize the process. Hardness measurements were carried out and microstructural studies were conducted to assess the spheroidization process and to determine the optimal spheroidization parameters.

Jan 1, 2007

By Zorigtkhuu Davaanyam, Bern Klein, Stefan Nadolski, Amit Kumar

"The High Pressure Grinding Rolls (HPGR) is a relatively new comminution technology that has been shown to be more energy efficient compared to semi-autogeneous (SAG) mills. Full and fair consideration cannot be given to HPGR-based comminution circuits in early stage projects, because presently pilot scale testing is required for assessing and sizing; pilot scale testing requires bulk samples weighing more than one tonne. A CAMIRO research program was conducted at the University of British Columbia to develop bench scale tests that would reduce the quantity of sample required to assess HPGR.Three test procedures were developed.1. The Direct Calibration Methodology calibrates piston press test results to pilot scale test results such that piston press tests can then be used to determine the energy–size reduction relationship for a range of ore types.2. The Database Calibrated Methodology, which is similar to the Direct Calibration Methodology except that it calibrates piston press tests against a database of pilot scale and piston press tests.3. The Semi-Mechanistic Methodology was developed to use piston press test results as an input for an HPGR based energy-size reduction performance model.Through utilization of these methodologies, the energy–size reduction performance of an HPGR can be predicted with minimal sample requirement. In addition, piston press testing is far more cost effective, faster, and accessible than pilot-scale HPGR testing.IntroductionOne could argue that in the future, decisions regarding selection of comminution circuits will be made primarily on the basis of energy consumption. The following facts and predictions support the argument:"

Jan 1, 2015

By Euclid P. Worden

INTRODUCTION Today, conventional raise boring is an accepted method of development in underground mines and on major construction projects. Over the years that this technique, and its associated machines and tools, have been under development, many articles have been written on the subject. To a great extent, these papers have reported operating results of one or more specific projects or have been generalized reviews of state-of-the-art machines and tools. This paper is intended as a review of the technique from an operational standpoint. Conventional raise boring, as opposed to the related variants box hole drilling and underground blast hole drilling, is a two step process consisting of the pilot hole drilling and reaming cycles. This author has covered the subject of pilot hole drilling in another article (1) . A good review of the current machines and equipment has been presented by Monroe (2) and an overall review of this entire technology was published by E&MJ (3) and Mining Journal, April, 1983 (4) . The subject of the reaming cycle is presented here together with some of the technical aspects of how the drilling tools are intended to be used. OPERATIONS Bit Change After the pilot bit has broken through at the end of the pilot hole cycle, a changeover takes place at both the machine and

Jan 1, 1985

Antimony ore samples (mean assay 18·7 per cent antimony) from Endeavour Inlet, Marlborough Sounds New Zealand, were tested for upgrading by flotation to a saleable product (60 per cent antimony).The effects of activating agents, collectors, frothers, pH, conditioning time, and particle size on the recovery and grade of a stibnite flotation concentrate were determined using HaIlimond tube and laboratory flotationcell test apparatus. Optimum flotation conditions for the ore were thereby established. A stibnite concentrate grading 63 per cent antimony and an overall recovery of 90 per cent is obtainable in a two-stage process.

Jan 1, 1977

By Mona M. Fawzy, Ahmed A. Eliwa, Ebrahim A. Gawad, Ahmed H. Orabi, Amal E. Mubark

The growing demand for rare earth elements (REEs) has led to numerous recent studies to recover these elements from various bearing ores and wastes. Therefore, the recovery of REEs from Ras Baroud polymetallic concentrate has been investigated in the current study. Physical beneficiation for the Ras Baroud pegmatite sample was carried out, yielding a concentrate for euxenite (Y), fergusonite (Y), xenotime (Y), monazite (Ce), allanite, thorite, uranothorite and Hf-zircon, which resulted in raising the concentrations of REEs, Th, Zr, U and Ti in the sample. Fusion digestion processes with sodium hydroxide were studied using the conceived predictive diagonal (CPD) technique. The three experimental digestion groups proved the dissolution of 99.9, 95.6, 99.9, 52.5 and 0.47 percent for REEs, Th, U, Ti and Zr, respectively, under fusion conditions of 723 K, 120 min, 1/1.5 ore-to-alkali ratio, and smaller than 100-μm particle sizes. Fusion kinetics, isotherms and thermodynamics were investigated using several suggested models, namely, pseudo reversible first order, uptake general model and shrinking core model, which matched well with the experimental digestion results. Selective recovery of actinide content from the REE content of the digested concentrate chloride solutions was accomplished using solvent extraction with di-2-ethyl hexyl phosphoric acid. About 99.9, 99.9 and 4.2 percent extraction efficiencies for Th, U and REEs were realized, respectively, using 0.3 mol/L solvent concentration in kerosene as a diluent, 1/2 organic-to-aqueous ratio, aqueous pH of 0.2 and contact time of 15 min. Thorium and uranium ions were stripped with 2.5 mol/L sulfuric acid solution with 94 and 98 percent stripping efficiency, respectively. A highly purified REE precipitate was obtained from the raffinate solutions. Zircon mineralization tailings were obtained as a byproduct through the alkaline digestion process.

Oct 1, 2024

By S. Narra, M. Nelles, I. Eickhoff, S. Teitge

"The aim of the research is to develop a holistic process flow for the recycling of glass fibres from glass reinforced plastics (GRP) and carbon fibres from carbon fibre reinforced plastics (CFRP), wherein the dissolution of the fibre epoxy resin matrix, separation of fibre fractions and their renewed material use is intended. In clear distinction to the previous research and development projects, the aim here is to recycle complex composite structures such as dismantled/disused wind turbine rotor blades and end-of-life composite wastes. In the course of the study, mechanical, hydrothermal and thermal processes and their combined procedures will be developed. As the fibre length is a decisive quality criterion in the recycling of composite materials, the further focus of the study will be the development of upstream and downstream material processing, in which the fibres are retained in their original form. The evaluation of the recycled fibres obtained is based on the elemental composition, measurement and morphological evaluation of individual filaments by scanning electron microscope (SEM), micro tensile tests on single fibres and their comparison to virgin fibres. The resulting process water is analysed by gas chromatography and mass spectroscopy (GC-MS) and a potential recirculation is determined. In cooperation with companies from the composite processing industry as well as recycling companies, a return of the recycled fibres to the known manufacturing process will be examined and an energetic and economic evaluation of the overall process will be carried out. Ambitious aim of the study is to achieve an actual recycling instead of the present downcycling or the energetic utilization. INTRODUCTION As global warming increases, so does the awareness of consumption and production of energy. To counteract the effects of global warming, renewable energy has been increasingly used during the last two decades, not only in Germany, but worldwide. Both, hydropower and wind energy, hereby play a fundamental role. After the end of their useful life of 20 to 30 years, the wind turbines (WTs) are being dismantled. Due to their foundations and tower segments, their recycling rate hereby exceeds 90% by mass. So far, the resulting rotor blade waste played a minor role accounting for only 2 - 3 weight-% of the total plant. Rotor blades of modern wind turbines are made of glass and carbon fibers, which are embedded in an epoxy or polyester resin matrix, balsa wood, PU or PET foams as fillers as well as various paints and coatings. These wastes currently end up in waste incineration or are sold to non-European countries."

Jan 1, 2018

By M. D. Heresy, H. F. Coward

"Whenever a manometer has been used for recording explosion pressures it has been calibrated under a series of static pressures. Whether the readings taken during the rapidly changing pressures of an explosion (dynamic pressures) truly represent the actual pressures therefore is an open question. The authors had hoped to solve this problem by conducting the calibration with the aid of known pressures, applied at about the ammo rate as in an explosion, for example, by means of a cylinder and piston, the piston being driven in by an eccentric cam at a rate which would be determined accurately by the shape and rate of revolution of the cam. If the rate of compression were great enough, then the pressure in the cylinder (to which the manometer is attached) could be calculated from the laws of adiabatic changes of pressure and volume. It seems highly probably, however, from H. T. Tizard's observations on pressure changes in a cylinder during rapid compression (55) 4/ that there is much heat loss, therefore pressure loss, in the very small interval of time during compression; although Tizard was able to estimate the amount thereof, he did so only by relying on his nanometer, which is exactly the procedure that the authors challenge on the grounds that the manometer was not standardized under the conditions of its use. Hence the authors were driven from this scheme of calibration to another, namely, comparing records of ono and the same explosion taken simultaneously on several instruments of as varied a type as possible. If 2 of a number of instruments agree, perhaps both are accurate; if 3 agree, probably each of the 3 is accurate; if 4 agree, it is almost certain each of the 4 is accurate.There was a second objective in the present work. If the Bureau of Mines and the B.C.D. (British Coal Dust) manometers differ in their records, then from a sufficiently comprehensive series of experiments it may be possible to coordinate the extensive results already obtained at the American and British stations.Thirdly, it was hoped to learn which is the best available instrument for observing the pressures of coal-dust and as explosions and, if possible, to indicate means for improvement in manometry."

May 1, 1935

By P. Botane, A. Cailleau

"Compagnie Miniere Esperance operates a gold primary ore body. The ore is processed through crushing, grinding and gravity concentration generating tailings with remaining fine gold. Analyses of the tailings proved a residual gold grade sufficient for a chemical treatment.As lab tests proved the technical feasibility of a pre-concentration using flotation, an on-site pilot operation has been carried out to assess the continuous circuit performances, define the best configuration and obtain enough data for the industrial circuit sizing.Data collected during the pilot campaign have been used for calibrating a process simulator built with the USIM™ PAC software. The simulator validated the feasibility of upgrading the existing plant, including the reprocessing of tailings to obtain a good fine gold recovery in a small amount of concentrate. A preliminary capital cost has been achieved to assess the flotation workshop profitability.INTRODUCTIONCompagnie Miniere Esperance (CME), a mining company based in French Guyana, operates a gold primary ore body in open pit. The ore is processed through crushing, grinding and gravity separation in two stages: a top plant and a bottom plant. A “coarse” pond contains tailings of the top plant; this product feeds the bottom plant. Tailings of the bottom plant are stored in the “fine” pond.Analyses of the fine ponds proved a residual gold grade sufficient for a chemical treatment. However, direct cyanidation would require a too large installation, regarding the local conditions (accessibility, supplying and meteorological conditions).It has been then decided to test the feasibility of a pre-concentration using flotation. Lab tests have been carried out by SGS Lakefield (Canada) in March 2007, which proves the technical feasibility."

Jan 1, 2009

1. New books P. Sarnoff. Trading in gold. Cambridge, Woodhead- Faulkner, 1980. 136 pp. £3.50 by airmail. Environmental Planning Professions Interdisciplinary Committee (EPPIC). Proceedings: Joint EPPIC/Habitat Symposium: Shaping Our Environment. Johannesburg, EPPIC (P.O. Box 61019, Marshalltown 2107), 1980. R3 per set of 2 issues. H. P. Patra and K. Mallick. Time-varying geoelectric sounding. Amsterdam, Elsevier, 1980. 420 pp. D.S. $87.75. Die Suid-AfrikaanseSteenkoolverwerkingsvereniging. Steenkoolvoorbereidingskursus. J ohannes burg, die Vereniging, 1930. 335 pp. Members of Chamber of Mines of South Africa R15, nonmembers R40. D. R. Derry. A concise world atlas of geology and mineral deposits. London, Mining Journal Books, 1980. HO pp. £26.25 byairmail. 2. Journal Remote sensing of environment (RSE). 3. NIM reports Report No. 2064 The on-line monitoring of gold in barren solutions. Report No. 2065 The determination, by X-ray-fluorescence spectrometry, of gold, silver, and base metals on activated carbon. Report No. 2068 The determination of platinum, palladiuim, rhodium, and gold in ores and concentrates by the fusion technique with lead as the collector. Report 2061 The determination, by anodic-stripping voltammetry, of copper and lead in silicate reference materials. Report 2062 The reduction by computer of photoplate data obtained by spark-source mass spectrornetry. Report 2071 The determination, by X-ray-fluorescence spectrometry, of tin and tungsten in scheelite and ca8siterite ores and concentrates. Tunnelling Tunnelling '82, the third international symposium in the series, is being organized by the Institution of Mining and Metallurgy, with the co-operation of the British Tunnelling Society, the Institution of Mining Engineers, and the Transport and Road Research Laboratory.

Jan 1, 1980

By Charles Will Wright

This paper will be of interest to those who are actually developing a mineral prospect or planning to do so, as well as to investors who are considering the problem of financing the development of the prospect, so that they may know what the risks are and what capital expenditures are necessary before a prospect may become a mine. The term "prospect" used broadly, as it is in this paper, is defined as any property that has a mineral showing of sufficient interest to warrant development, irrespective of prior work, Such previous exploration, however, may be extensive and consist of several tunnels or adits connected by raises, or of shafts with several levels. There may also be a small mining and milling plant on the prospect which, because of the lack of capital for development or the lack of markets for the products, is now idle. Such prospects may warrant further capital investment for development work or for a mine plant to raise to the stage of profitable production.

Jan 1, 1935