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By Robert Perlman

El presente texto señala las nuevas técnicas cuantitativas que pronostican los términos cortos y largos de los precios de los metales. Estos métodos permiten la construcción de un modelo de comportamiento que comprende matemáticamente los diferentes tipos de sistemas económicos. Un modelo económico consiste en un sistema de ecuaciones que indican cómo trabajan los mercados. Para ello, los ingenieros de diseño aplican esta clase de construcción de modelo a sistemas fsicos como puentes, refinerías. La diferencia entre este tipo de modelo y un modelo económico es que la relación entre las variables con las que el ingeniero trabaja pueden ser complejas, pero están basadas en conocidas leyes físicas exactas, mientras que el economista usualmente tiene que identificar las relaciones por sí mismo y éstas nunca son exactas.

May 1, 1973

By E. S. Moore

"The Centre of the silver-producing section of the Gowganda area lies about 55 miles northwest of Cobalt, and the village of Gowganda is 71 miles by road from New Liskeard. The geological similarities of the Gowganda and Cobalt areas led prospectors westward from the rich Cobalt field, first to Elk Lake and then on to Gowganda, where mineralization was found in 1907. A year later many showings were found, and rich hand-picked ore was shipped. Most of the ore has come, however, from two mines, both of which are still operating; the Miller Lake-O'Brien, which was purchased by Siscoe Metals of Ontario Ltd. in 1945, and the Castle-Trethewey. The annual production of these two mines runs over one and one-half million ounces of silver and considerable cobalt. The total production of the camp has reached about 32,000,000 ounces of silver and a large amount of cobalt, the total not recorded.General GeologyThe general geology of Gowganda is in many respects much like that of Cobalt. There are areas of Keewatin basic and acid Javas mixed with tuffs and basic intrusions. These rocks are deformed and partly altered to schists, and have been intruded by some Haileyburian basic and ultra-basic rocks and by Algoman granite. These were followed by a large number of porphyritic Matachewan quartz diabase dykes. After a period of extensive erosion the Huronian sediments were deposited on a pene-planed surface over all the older rocks; these sediments include large quantities of conglomerate (partly tillite), quartzite, and greywacke. The Keweenawan rocks include the Nipissing quartz diabase sill, later quartz diabase dykes, and one long olivine diabase dyke, the latest Precambrian rock. The area has been extensively glaciated.Structural FeaturesThere has been little folding in the area since the Algoman batholiths were intruded, and the Huronian sediments lie nearly flat, with dips of 10, 15, or rarely 25 degrees. The Matachewan dykes show a remarkably uniform, nearly north strike, indicative of east-west tension when they were intruded. On the other hand, the dykes later than the sill strike nearly east, tangentially to the northeasterly and northwesterly strikes of the Miller Lake basin."

Jan 1, 1949

By Paul M. Tyler

The technology of clay and the manufacture of ceramic products therefrom, and also the clay resources of most of the individual States, are already covered by a voluminous literature. The present resume touches these matters only briefly; its purpose is essentially to bring together in small compass certain of the elementary factors affecting the potential commercial value of a clay deposit. In its preparation the author made extensive use of the annual chapters on Clay in Mineral Resources of the United States and in the two annual issues of the Minerals. Yearbook that succeeded them. For careful review and constructive criticism of the manuscript, the author is indebted to Hewitt Wilson. GENERAL DESCRIPTION The term ?clay? includes a great variety of substances that may differ widely in chemical mineralogical and physical properties. No two clays are exactly alike. All of them however, have the prominent characteristic of becoming more or less plastic when wet. Nearly all of the useful clays can be molded into articles, will hold their shape while being dried, and can be converted into a hard, rocklike substance by heat. Clay may, and in fact usually does, consist of a number of minerals among the commonest of which are kaolinite, quartz, feldspar, iron oxides, mica, bauxite, calcite, and manganese oxides. Organic matter is often present. Pure kaolinite, which has the formula A1203. 2 SiO2. 2H2O, is ordinarily, considered to be the parent "clay substance," butt most clays contain other hydrated mixtures of alumina and silica (aluminosilicic acids) along with indefinite amounts of sand and other nonessential minerals3/ Even, this so-called inert matter affects the plasticity, drying shrinkage, ease of drying, and final density, and at high temperatures may react chemically with the clay substance.

Jan 1, 1929

The Health Tracking project is one of five projects being undertaken as part of the Minerals Industry Cooperation Initiative (MICI) û a national initiative sponsored by the Minerals Council of Australia. The aim of the Health Tracking project is to assess the practicality of ways to demonstrate the monitoring of hazardous exposures and the occurrence of related occupational illness and disease and development of management systems and strategies at a national level. This second stage of the project will be completed in 2005 and will cover four areas: pilot development of a comprehensive job exposure matrix (JEM) for the minerals industry; development of both proactive and reactive occupational illness and disease metrics; recommendations regarding appropriate health tracking models; and provision of best practices guidelines for management of occupational health. The synergies between these areas will establish the path towards an effective national occupational health surveillance system and the development of effective prevention strategies and policies.

Jan 1, 2005

By Henry M. Howe

PART I. § 1. Introduction. After giving certain definitions, this paper gives the reasons which led to Roozeboom's form of the diagram of the freezing-point curves and general equilibrium of the iron-carbon compounds, steel and cast-iron ; and then those which led to replacing it with the present or double diagram, in which graphite is at all temperatures held to be the more stable and cementite the less stable (metastable) form of carbon. Next in § 10 the evidence supporting this greater stability of graphite is examined, then in § 17 that which seems to oppose it, and in § 22 a summary of the evidence is presented. The second part of the paper considers the topography of the graphite-iron diagram, rejecting summarily the solubility-lines based on the data of Charpy and Grenet and of Mannes-mann, on the ground that the data even on their face do not really point toward these lines, and that they are wholly incompetent to determine any solubility-lines whatsoever, because they report together with the dissolved carbon also an indeterminate quantity of cement-carbon, and because even such carbon as is actually dissolved, only in part represents the solubility of graphite, and in another and indeterminate part represents the solubility of cementite, or at least of carbon in presence of cementite as distinguished from graphite. It might be thought that graphite is but slightly soluble in iron, because of the absence of any suggestions of eutectoid graphite, corresponding to the eutectoid cementite of pearlite in very many cases in which the cast-iron seems to consist of ferrite and massive graphite only, and because of the micrographs of Goerens and Gutowsky. In these the primary austenite of cast-iron quenched but little below the eutectic freezing-

Jan 7, 1908

By C. F., Christopher

The purpose of any steel-making process is to convert the two raw materials iron and scrap into steel. The chemical analysis of the steel is set within certain limits which involve the physical proper- ties desired by the consumer. In addition to tensile properties a large number of other properties are at the present time desired, such as impact resistance, grain size regulation, specific degrees of hardenability, resistance to creep at high temperatures, resistance to expansion on heat treatment, the ability of the product to undergo extreme amounts of cold deformation without failure, and many other properties which are not directly related to the specified chemical analysis. Variations in many of the properties of plain-carbon steels are due to elements and compounds not included in the ordinary "five element"§ composition. Such variations result primarily from variations in oxidation of the metal in the furnace and from the deoxidation method employed. The steel-making problem therefore resolves itself into two distinct sections: (I) the elimination of certain elements from the charge (the iron and scrap entering the furnace) and the addition of materials to meet the chemical specifications for the heat; (2) the manipulation of the slag and metal and the process of deoxidation to give certain desired properties in the steel entirely apart from the chemical analysis specified. Each of 'these two ends must be attained

Jan 1, 1957

By M. E. Bell

The term "operational research" was probably first used to describe work started under E. C. Williams, now Director, SHAPE Air Defense Technical Center, late in 1937 or 1938, at the Bawdsey Research Station of the British Air Ministry, a laboratory center concerned with the development of radar equipment. After the practicability of the early techniques had been demonstrated, a large (for those days) program of development and installation was authorized. It was very soon realized, both by the Royal Air Force and by the scientists that almost as important as the gear itself was the way in which it should be used. Accordingly, it was decided that some scientists should cooperate to study the way in which the equipment should be deployed and operated in conjunction with the Royal Air Force. To distinguish this work from the normal work of a research and development establishment, the term "operational research" was coined. It merely meant at this time that this particular section of scientists was to be concerned with the use of the gear rather than with its technical development and it seemed natural to those concerned to adopt the word "operations" which has a specific connotation in the armed forces.' This method was later extended to peacetime business enterprise, government operations and other human activities. Operations research appears to have penetrated the extractive industries more slowly and less completely than other industries, the military, or the government. This may be due (1) to a difference in the attitude of management towards operations research, or towards research of any kind, for that matter; (2) to unsuitability of the extractive industries for application of the operations research method; (3) to inaccessibility of the data; (4) or to a lack of trained personnel who are interested in applying operations research to the mineral industries.

Jan 8, 1963

By R. E. Vivas, J. A. Villa

"Located in the state of Colima, Peña Colorada is one of the largest iron ore operations in Mexico. The project is owned in equal parts by ArcelorMittal and Ternium. Though boasting a production capacity of 4.1 Mt/a (4.5 million stpy) of concentrate per year, Peña Colorada is faced with declining ore grades. In order to respond to this situation, Peña Colorada had to expand production even further. This expansion created various challenges that were overcome by the adoption and application of new technology. Examples of these technological innovations are discussed in detail in this article and include improvements in geo-modeling, mine planning, and mine operations. The successful implementation of these technologies paid for itself many times over, and has led to significant improvements in production and performance, while lowering the operating costs and reducing the variance between planning and execution.Project overviewPeña Colorada is a mining company that produces about 30 percent of the iron ore in Mexico. This project generates about 1,200 direct jobs and 3,000 indirect jobs, making a significant contribution to the local economy. Similarly, Peña Colorada invests in its local communities through numerous educational programs, scholarships, university agreements, social development, environmental agreements, etc. Peña Colorada’s operations consist of an open pit mine located in Minatitlán and a pellet plant located in the port city of Manzanillo, as shown in Fig. 1. Technological innovationsMost mining projects around the world typically follow the logic of “mining the next best ore.” Consequently, head grades tend to decline over the life of the mine. In the case of Peña Colorada, a decline in head grade combined with a decline in iron ore prices forced the operation to adapt to a new business environment and adopt new technologies to face these challenges. However, the first step along this process was to increase the confidence and reliability of the resource model. This task involved additional drillhole campaigns coupled with more detailed modeling techniques. Once the block model was completed, new optimization studies and production schedules were evaluated with new optimization tools that improved many aspects of the mine plan. The Peña Colorada block model has undergone 3 expansions to reflect additional information not available in the past. The model has expanded to the East and Southwest. The latest model expansion increased the total number of benches to 98 as a result of positive exploration results. Similarly, new geotechnical studies were prepared, which provided new guidelines for pit slope design, and new technology was implemented to monitor ground movement and slope stability. Two sectional block model views in Hexagon Mining’s MineSight 3D, along with the pit designs and geologic solids are shown in Fig. 2."

Feb 1, 2017

By Charles G. Maier

"INTRODUCTION The use of thermodynamic calculations to answer practical problems in metallurgy, especially those that are relatively difficult to test experimentally, is rapidly becoming a conventional method of procedure. Nevertheless, these methods cannot he applied effectively until the fundamental thermodynamic constants used for them have become available either by direct experiment or by recalculation of data already existing in more or less undigested form.In an attempt to collect such data far the compounds of lead and the antimony group the incentive has been to make a preliminary survey that will disclose the gaps or questionable phases of available information and to collect data that may be used to answer certain rather practical problems presented by operating metallurgists.This report comprises three sections; the first gives the basis of selection of the constants which may now be given or estimated, and the later sections discuss the application of the figures obtained to two of the more interesting problems.The reader will discover that many of the quantities involve critical study of a number of more or less discordant observations. Although certain data could be rejected on the basis of thermodynamic comparisons, it must not be overlooked that many of the figures are the results of rational estimates rather than exact experiment. The use of thermodynamic methods to control and partly authenticate such estimates is one of its most valuable characteristics for the practising metallurgist or chemist, who cannot check by direct experiment each property of the materials which he converts to usable form.Nevertheless, while it is definitely possible in certain instances that the final figure selected for the heat or free energy of a process or substance may be in error by as much as a few hundred to a few thousand calories per formula weight, questionable figures are usually revealed by the thermodynamic calculations made. When quantities of such degree of accuracy are, and they often must be, used for estimating an unknown reaction, the result often gives no more than the order of magnitude of the desired quantities. Yet even in these extreme cases the answer is far more reliable and valuable than an unordered guess or a conclusion based on incorrect data."

Dec 1, 1934

By M. W. Hildyard, M. O. Kataka

Seismic integration schemes aim to incorporate the rock mass response provided by the historical seismic activity to improve the ability of numerical models to reproduce future response to mining. Up to now, integration schemes considered the events using quasi-static models. This paper presents case studies that consider some of the seismic and modelling issues needed to extend these schemes to include the dynamic characteristics of seismic events. The ultimate aim of an automated integration scheme seems impractical for dynamic modelling. The predictions of the WAVE elastodynamic finite difference program are, however, suitable for modelling limited numbers of events to determine either the near-field velocities and damage or the effect of fractures and excavations on the far-field low frequency response. Les projets d’intégration sismique ont le but d’incorporer la réponse de la masse rocheuse à l’activité sismique historique pour améliorer la capacité des modèles numériques à reproduire la réponse future à l’exploitation minière. Jusqu’à présent, les projets d’intégration étudiaient les évènements avec des modèles quasi-statiques. L’étude présente révèle des études de cas qui considèrent certaines des questions concernant modelage et séismes qui sont nécessaires pour porter plus loin ces projets en incluant les caractéristiques dynamiques des évènements sismiques. Le but final d’un projet d’intégration automatisé semble impraticable pour la modélisation dynamique. En revanche, les prédictions du programme élastodynamique par la méthode des différences finies WAVE sont appropriées à la modélisation d’un nombre limité d’évènements de façon à déterminer soit les vitesses à petite échelle et les dommages, soit les effets des fractures et excavations sur la réponse de basse fréquence à grande échelle. Seismische Integrationsschemata zielen darauf ab, Reaktionen der Gesteinsmasse, die von den Berichten seismischer Aktivitäten stammt, zu inkorporieren um numerische Modelle in die Lage zu versetzen, künftige Antwort zum Bergbau zu reproduzieren. Bis dato betrachteten Integrationsschemata die Fälle mit quasi-statischen Modellen. Diese Arbeit stellt Fallstudien dar, die einige der seismischen und modellierenden Fragen betrachten, die benötigt werden, um diese Schemata auszuweiten, um die dynamischen Charakeristika seismischer Fälle einzuschließen. Das Endziel eines automatisierten Integrationschemas erscheint für das dynamisches Berechnen undurchführbar. Die Vorhersagen des WAVE elastodynamisch begrenzten Unterschiedprogramms sind jedoch verwendbar für das Berechnen von begrenzten Anzahlen von Fällen, um entweder die Nahfeldgeschwindigkeiten und Schaden oder den Effekt von Brüchen und Extraktionen auf der Fernfeld Niederfrequenzantwort festzustellen.

Jan 1, 2003

As the chief field of the gold dredging industry in Otago is the district traversed by the Molyneux River (called above Cromwell the Clutha) and its tributaries, a brief reference to the geology of that region and the origin of its alluvial gold will not be out of place. The prevailing rocks are metamorphic schists, chiefly mica and quartz schists, pr.obably of Silurian age. Though these rocks do not contain many payable quartz reefs, gold appears to be distributed in small quantities all through them,chiefly associated with the quartz lamime and lenses. The river drift, however, contains numerous pebbles of quartzite, quartzoze conglomerate, and fme-grained slate. Seeing that these rocks are hardly known to occur in situ within the watershedof the Molyneux River, though Devonian and carboniferous rocks of similar character occur to the north-east and south-west, it seems probable that the schists were at one time overlaid by carboniferous and Devonian rocks, and that these have been removed by denuding agencies. Be this as it may, it is certain that the schists themselves have been greatly eroded by the action both of water and of ice, and that the resulting drifts have themselves, in many cases, been sorted and re-assorted by the same agents.Consequently the drifts are very varied in character and often developed on a grand scale. In geological age they vary from Early Tertiary (though some may be older) to Recent.

Jan 1, 1903

By H. Kinilakodi

In 2008, the authors developed a methodology for identifying underground coal mines at high risk for major-hazard events. It focused on major hazard-related violations of safety standards associated with high-risk conditions. Later, using a sample of 103 mines with 2008 and 2009 data, injury measures and U.S. Mine Safety and Health Administration (MSHA) citation data were combined into a safe performance index (SPI). The SPI was used to assess the relative safety-related risk of mines, including by mine-size category. In this paper, comparisons are made of SPI-associated, normalized safety performance measures across mine-size categories, with emphasis on small-mine safety performance as compared to large and medium-sized mines. Mining Engineering, 2011, Vol. 63, No. 10, pp. 73-77. Official publication of the Society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By C. E. Wicks, F. E. Block, F. D. Stevenson

The vapor pressures of tungsten (VI ) chloride ( WC1 ) and hafnium ( IV ) iodide ( HFI ) were measured by a metal diaphragm technique . Vapor pressure values were obtained to permit calculation of the thermodynamic properties of the vaporization processes of the compounds . The vapor pressure data of WC16 are represented by the following equations for the liquid , B - solid , and a- solid over the temperature intervals indicated : - log P = 8.194 3,253 /T Liquid , 281.5 ° to 325 ° C : B - solid 230.0 ° to 281.5 ° C : log P a - solid 185.0 ° to 230.0 ° C : log Pam *** = 8.794 - 3,588 / T = 9.615 - 3,996 /T where T is the absolute temperature in degrees Kelvin . The heats of vaporization and sublimation are 14.9 , 16.4 , and 18.3 kcal / g mole , respectively . The entropy of vaporization at the normal boiling point , 330 ° C , was 24.3 eu . The fusion temperature , 281.5 ° C , and transition temperatures , 230.0 ° and 185 ° C , were found by thermal analysis .

Jan 1, 1964

By W. R. Dengler

Dynatec Mining Limited contracted to sink a lS00 metre (4960 ft.) concrete lined shaft for Falconbridge Nickel Mines in Sudbury, Ontario, Canada. The shaft is 6.3 metres (20.S ft.) in diameter inside the concrete lining and is equipped with steel furnishings. Dynatec used the owner supplied 4.6 metre (l5 ft.) diameter double-drum hoist to sink the shaft with 12.S tonne buckets for muck removal and 4 cubic metre concrete buckets for concrete placement. One of the unique features of the shaft sinking operation is the use of a four-boom electric hydraulic drill jumbo permanently mounted in the shaft sinking stage. This paper will describe the performance obtained with the electric hydraulic drilling equipment and the high capacity muck removal and concreting equipment.

Jan 1, 1992

By E. Wraith, W. W. Culver, B. Wesstrom, P. J. Mackey

Electrodeposited copper of the 1860s was of unprecedented purity, although the profound significance of this achievement was not fully realised until the dawn of the electrical age a decade or so later. By the 1870s there were three somewhat large (4 to 4.5 tonnes Cu/day) electrolytic copper refineries in Germany based on J. B. Elkington’s process, first patented in the United Kingdom in 1865. More such refineries were planned throughout Europe. At the same time, copper output in the U.S.A. was starting to expand and with the spread of European electrolytic copper refining technology across the Atlantic, the door opened to major increases in North American output. The technology was first taken up in 1879 by James Douglas at the Chemical Copper Company in Phoenixville, Pennsylvania, where he was Superintendent. Douglas was assisted in this pioneering work by Edward Weston. The copper refinery at the Chemical Copper Company was small, not unlike the first plants in Europe. The present authors contend that the electrolytic copper refinery at the Chemical Copper should be regarded as the first copper refinery in the United States. The Balbach Copper Refinery in New Jersey, which commenced operations in 1883 with an initial production of about 2 tonnes Cu/day, has been erroneously considered as the “first commercial refinery”; it rightly belongs in second place. The early developments at these plants are discussed in this paper. INTRODUCTION In the mid-1800s, the main uses for copper were as sheathing on the wooden sailing ships of the day to protect from marine growth, boiler components in locomotives and steam engines, along with some construction uses. Copper ores were generally smelted, and further fire-refined for market. The recovery of gold and silver, if present in payable amounts, was a slow and relatively expensive step. This situation regarding copper would change by the 1870s with advances in the generation and use of electricity. The introduction of the dynamo led to major developments in electrorefining. First demonstrated in principle by Faraday in 1831 (Faraday, 1832), the dynamo was subsequently adapted and further developed by J.S. Woolrich for electro-metallurgical applications in 1842 (Woolrich, 1842; Napier, 1845). It provided a new source of power with the unprecedented potential to significantly change the scale of metal production by electrometallurgy. Interestingly enough, copper would be needed for the electrical age just beginning. By 1869, advances in dynamo design offered relatively reliable large machines, which enabled J. B. Elkington in the United Kingdom to use the dynamo in the radically new Pembrey copper electrorefinery — the first copper electrorefinery in the world (Wraith, 2013). Initial production at Pembrey was small — in the range of 1 to 2 tonnes/day — while gold and silver were recovered more readily by the treatment of the slimes than with methods used hitherto.

Jan 1, 2019

By AIME AIME

T HE 133rd meeting of the A. I. M. E., opening in New York on Feb. 15, promises to be as successful technically and socially as any in the past. The papers submitted for the various technical sessions are unusually excellent and insure something of interest to every group. Tentative programs have already been issued, and a concise resume of the various sessions, arranged chronologically, appears on page 48. Among the many interesting technical sessions arranged, attention is directed to those of the Petroleum Division, embracing the Symposium on Production that has come to be an annual feature, and new ones on refining practice, transportation and economics. The Institute of Metals program is similarly comprehensive. It includes 15 papers, 8 on copper, 4 on aluminum and its alloys, and one each on magnesium, lead, and fatigue of metals. The Coal Committee offers as a leading contribution its report, prepared under the direction of H. N. Eavenson, giving a new analysis of the capacity of the mines and a comparison of coal with other industries. This will be supplemented by a number of other papers of especial interest to operating men, among which are "Data on Use of Loading Machines in Bituminous Mines," by Graham Bright; "Evaluation of Coal," by R. H. Sweetser; "Selection of Coals for the Manufacture of Coke," by H. J. Rose; and "Relation of Origin and State of Carbonization of Coal to Problems of Low Temperature Carbonization," by S. W. Parr. The Iron and Steel Committee has scheduled seven papers, and there will be a special session on open-hearth practice, in which will be presented the first results of the two conferences, held by the sub- committee at Pittsburgh and Cleveland. A symposium on molding sands will be a special feature of the session on non-metallics.

Jan 1, 1926

By Keith L. Harris

The performance of the world economy improved significantly in 1984. Real world output!/ grew 4.3% (compared with 2.6% in 19831, the highest since the 4.4% increase recorded in 1978 (table 1). The output of industrial nations rose 4.9%, while that of the developing nations rose 3.7%. The United States and Japan had the largest increases in output of the major industrial nations, with respective increases of 6.8% and 5.8% (table 2). The components of real output with the most significant growth in the industrial countries were gross fixed investment (9.2%), consumer expenditure (3.1%), and public consumption (2.5%) (table 1). Industrial output, as measured by industrial production indices, has returned to about the 1980 level for most of the major industrial nations (table 2). Exceptions to this were industrial production in Japan and the United States; Japan's industrial production rose steadily throughout the 5-yr period and is now more than 16% above the 1980 level, and the industrial production index for the United States reached 11 1.2 (1980=100.0). Real total domestic demand grew at 8.7% in the United States, more than double the rate of Japan, which, at 4.0%, had the second-largest growth. Average demand for all industrial countries was up 5.1%. During 1984 the U.S. dollar showed great strength on international markets, contributing to large current-dollar negative net exports of goods and services and even larger negative net exports of the merchandise sector. While growing U.S. imports helped spread the benefits of the recovery, they also led to a widening of current account imbalances and growing trade tensions throughout the world.3/, 4/

Jan 1, 1985

By G R. Ballantyne, M S. Powell

A comprehensive Australia-wide survey of comminution energy consumption at copper and gold mines was presented by the authors at the 11th AusIMM Mill Operators’ Conference 2012. The database has been extended to include major overseas mines and used to benchmark comminution energy consumption across the industry. The mines included in this study now represent 15 and 24 per cent of the total global gold and copper production respectively, and almost all Australian production. The comminution energy intensity per unit of saleable metal has been presented in a graphical form similar to a cost curve used in economics. The graphical method has been developed to assess the competitive advantage that can be achieved by reducing comminution energy intensity.This benchmarking tool has been applied to three published case studies to assess its applicability. The first case study indicated that a large reduction in size-specific energy (kWh/t -75 µm) was achievable by converting standard semi-autogenous and ball mill circuits to include high pressure grinding roll and stirred mills. The second case study investigated the metal-specific energy reduction historically achieved by Bougainville with the addition of a preconcentration screening plant. The final case study was conducted by Barrick Gold Corporation and involved incremental efficiency upgrades at three of its gold mines: Cortez, Cowal and Mara North. The application of the benchmarking tool to each of these case studies successfully demonstrated the scale and competitive advantage that was achieved by reducing energy intensity.CITATION:Ballantyne, G R and Powell, M S, 2014. Benchmarking comminution energy consumption for improved efficiency, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 95–100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By Ivan E. Goodner, Charles H. Fulton

THE subject of the constitution of copper-iron mattes has received considerable attention in recent years by Keller,1 Bolles,2 Hofman,3 and Gibb and Philp.4 Still more recently Friedrich, Röntgen, Wiedmann, Heyn and Bauer, and Leroux have published, in some instances, elaborate researches on the various systems of the sulphides, and the sulphides and their respective metals, which enter into the constitution of mattes, and have added very greatly to the knowledge of the subject. The work of Friedrich has been especially fruitful. But to date no effort has been made to correlate the data obtained in the latter researches and apply then to the study of the product called " matte," which is made in such large quantities by copper and lead-smelters. In this paper we propose to determine, by metallographic and chemical means, the constitution of copper-iron and copper-lead mattes in the light of the recent data above mentioned. We do not discuss copper-nickel mattes or speisses (artificial arsenides). The paper is divided into three sections I. A review and discussion of the various binary systems of the metallic, sulphides, and the binary systems of various metals and their respective sulphides entering into the constitution of mattes; also a discussion of the physical and chemical properties of these sulphides. II. A description of the results obtained from the chemical and metallographic examinations of the samples of copper-iron and copper-lead-iron matte obtained from various plants.

Nov 1, 1908

By Eti Purwaningsih, Widi Astuti, Erik Prasetyo

Selective-reductive leaching of manganese from low-grade manganese ore using tannic acid as a reductant in acidic media was demonstrated by XRD, SEM-EDX characterization, and batch leaching studies at room temperature. The pH change in the liquid phase before and after leaching revealed that selectivity of manganese over iron was due to the hydrolysis of iron. The acidity in the liquid phase during leaching was dictated by two mechanisms: proton-consuming reaction (manganese oxide reduction by tannic acid) and proton-producing reaction (ferric ion reduction by tannic acid to produce ferrous ion). Based on the leaching studies, the more prevalent reaction between these two was determined by initial leaching conditions: tannic acid concentration, sulfuric acid concentration, liquid-solid ratio, temperatures, and agitation time. Kinetic studies revealed that maximum recovery was attained within 6-h agitation, which indicated a product layer diffusion process.