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By Tiago Seixas Bittencout

No cenário econômico mundial atual, cada vez mais as indústrias têm voltado sua atenção para o reaproveitamento de materiais gerados como consequência das ações operacionais, tanto como forma de reduzir custos, como também no caráter de sustentabilidade do negócio. Em uma operação de refino primário em aciaria elétrica, onde o produto é o aço líquido, o antes considerado resido, mas agora denominado de coproduto, a escória, passa atuar diretamente no custo final do produto quando esta é processada, e passa a compor a carga fria usada no processo de elaboração do aço. Neste sentido, o estudo deste material se faz necessário para a compreensão de qual será o seu comportamento junto aos processos e quais vantagens e desvantagens da sua aplicação. Neste trabalho, foram feitas as caracterizações de sucatas provenientes de reaproveitamento de escórias produzidas em Forno Elétrico a Arco e em conversor LD, bem como seu impacto no refino primário, como parte integrante da carga fria no FEA.

Aug 17, 2017

By Thomas A. Davidson

The Bureau of Mines Helium Field Operations has developed a simple and accurate method for calculating the viscosity of gas mixtures. Only the composition of the mixture and the molecular weights and viscosities of the pure components in the mixture are required. The momentum fraction of a mixture is calculated from the composition. The fluidity is calculated as a quadratic function of the momentum fractions. The efficiency factor for transfer of momentum in collisions between bodies of different masses is derived and used with one empirical constant. The viscosity is the reciprocal of the fluidity. Results of the method are compared with 752 reported viscosities for 40 dilute binary systems at temperatures from -78 to 276.9°C. Using this method the average absolute deviation is 1.29%, the root-mean-square deviation is 1.99%, and the average deviation is -0.84%.

Jan 1, 2010

By Joseph F. Shirley

A froth flotation plant to recover byproduct molybdenite must be designed specifically for the selected separation process and the type of ore being treated. However, some general rules concerning byproduct molybdenite plant design can be suggested that would be valid for most processes. The term byproduct molybdenite in this paper is limited to the recovery of molybdenite from copper porphyry ores, which essentially amounts to selectively separating molybdenite from copper and iron sulfide concentrates. In addition, most of the discussions would apply only to the almost universally used approach of floating the molybdenite and depressing the copper and iron sulfide minerals. Thickener It is considered essential that the feed to a byproduct molybdenite plant be thickened prior to being treated for molybdenite recovery for the following reasons: 1) Thickening allows the rougher and any preconditioning stages to be operated consistently at the optimum percent solids. 2) Generally, the size of equipment used for pretreatment and the rougher flotation is considerably smaller and less expensive than if the copper flotation concentrates were treated directly. 3) The removal of as much water as practical by thickening removes flotation reagents added in the copper flotation circuit, especially frother which can be quite troublesome in a byproduct molybdenite plant. Although thickening of the molybdenite plant feed has long been recognized as necessary to optimum metallurigcal results, very often this area has been designed poorly. The thickener should be sized so that it can produce a consistent thickened product containing 60 to 65% solids without the use of flocculants. Some plants are only able to thicken to 45 to 50% solids consistently while other plants let the percent solids vary from 45 to 60% over a 24-hr period. While the former is more desirable than the latter, in many cases better metallurgical results could be obtained if the percent solids could be held consistently close to 60%. Probably the simplest and most satisfactory system of handling the thickener underflow is to spigot it into a sump, using a sphincter type valve for the orifice, controlled by a density meter. Another satisfactory approach is to use an ODS type pump to meter the underflow. There are other methods of handling thickener underflow which work satisfactorily as long as the amount of copper concentrates entering the thickener is relatively uniform. However, they often fail to operate satisfactorily when there are large fluctuations in the thickener feed rate due to fluctuations in ore tonnage and/or copper grade. If the percent solids in the plant feed could be held close to 65%. There is the possibility the molybdenite plant tailing would not have to be thickened prior to the copper filter plant. This means that the molybdenite rougher float would have to be conducted at 45 to 50% solids with all the cleaner tailings returned to the rougher for dilution. Admittedly, in some situations this approach would be impossible, but if capital or plant area is limited, it should be considered.

Jan 1, 1981

By Jean-Christophe Ehrström, Fanny Mas

"A specific test set-up has been developed to study at the lab-scale the high-temperature behavior of aluminium alloys in conditions close to those experienced by thick plates during hot-rolling. A particular attention is paid to reproducing both the stress triaxiality and strain fields that exist in plate during rolling. In addition to standard ductility measurements by means of secondary tensile tests (STT), multi-step plane strain compression (PSC) tests have been performed to mimic hot-rolling pass schedules. Tool and sample geometries were adapted to allow low h/a ratios (h= average specimen thickness, a= tool width) and thus guarantee depressive stress conditions at the center of the specimen during most of the test. Such conditions resulting in porosity opening can then be used to investigate the impact of rolling conditions on damage evolution. The mechanical testing was combined with post-mortem high-resolution ultrasonic scans allowing to detect small amounts of damage and quantify its evolution as a function of processing parameters such as strain and temperature. The test set-up was validated on two 2050-type AlCuLi alloys with different susceptibilities to high temperature embrittlement.INTRODUCTION Aluminium thick plates are widely used in the aerospace industry, mainly as semi-products to be machined for internal structure parts of wings (spars, ribs) and fuselage (frame). The conversion route of such products always involves a hot-rolling step, the conditions of which (temperature, speed, pass schedule) have to be optimized to maximize both mechanical properties and final plate quality. This goal cannot always be efficiently achieved by full-scale industrial trials as (a) cost limits the number of possible test conditions and (b) it is often difficult to change one parameter alone. That is why there is a need for laboratory-scale tests able to mimic the rolling process in terms of temperature, strain rate, stress triaxiality and deformation. Most laboratory hot-rolling mills do not adequately simulate industrial processing routes, especially in terms of heat loss, deformation speed and rolling geometry (maximum roll gap vs. work roll diameter). Concerning thick plate, it is of interest to achieve both similar deformation and L/h ratio (L=arc of contact, h=mean gauge) per pass as the industrial schedule because they are simultaneously involved in damage evolution and void closure during hot forming processes (Saby, 2014)."

Jan 1, 2018

By C. C. Hwang

The Bureau of Mines formulated a method for calculating the concentration of entrained dust from a dust deposit by a turbulent gas stream. In particular, a diffusion equation is used to calculate dust concentrations in a channel following an explosion. Dust leaving the channel walls was treated as originating from stationary or moving, and single or multiple material sources. Formulas and sample computations for various types of dust sources in circular and rectangular channels are given, based on experimental entrainment rates. The analysis predicts the dust concentration as a function of time and channel space. The results appear to agree with the physical characteristics of explosion-driven dust dispersion in a O.6-m-diameter, 50-m-long explosion tunnel. The analysis is also applied to simultaneous and consecutive dispersion of coal and rock dust from simulated coal mine surfaces (walls, floor, roof, and ribs).

Jan 1, 1974

By G. G. Brown

Enthalpy-entropy diagrams are presented for natural gases of 0.6, 0.7, 0.8, 0.9, and 1.0 gravity over the pressure range of 5 to 10,000 Ib. per sq. in. and temperature range of 32º to 700°F. The charts indicate directly the work requirement and temperature rise for adiabatic compression or temperature change for free emansion of natural eases. Computation and Uses of Charts The Mollier diagram (Fig. 4), in which the enthalpy (heat content) is plotted against the entropy with lines of constant temperature, pressure,, and in some cases volume, has been found most convenient when dealing with the compression, expansion, and flow of fluids. In dealing with the flow of fluids, the sum of the increase in the enthalpy, AH, plus the increase in kinetic energy, AM —, plus the increase in potential energy, ?MZ, representing the total increase in energy of the fluid in flow, is equal to the sum of the heat q, and work added, —w, to the fluid while flowing between the entrance and exit of the flow system. AH + AM— + ?MZ = q-w [1] In cases where there is no significant change in potential energy or in kinetic energy (velocity), it follows that the increase in enthalpy is equal to the total energy supplied to the fluid. Under such conditions' the changes in the property of the fluid as it flows through a throttling valve, choke, or any other similar arrangement, may be read directly from the enthalpy-entropy diagram by following a horizolltal line between the known pressures' When compressing Or expanding a gas by means of a Or or engine in which no heat is added to or subtracted from the gas, but only work done, the changes in the properties of the gas may be determined along a vertical line of constant entropy between the entering and exit pressures. The power required for the compression of the gas may be readily determined by converting the increase in enthalpy into the desired units. The enthalpy-entropy diagram for natural gases is to the gas engineer what the steam diagram is to the steam-power engineer. For this reason it would be extremely convenient if a reasonably satisfactory enthalpy-entropy diagram could be prepared as a function of the gravity of the gas. A careful study of the known properties of natural gas indicate that this is possible. The effect of temperature upon the enthalpy at constant pressure is expressed as the "heat capacity" or "specific heat" of the gas. The best available data for natural and petroleum refinery gases indicates the relationship shown in Fig. I. From this it is clear that the specific heat of natural gases is a function only of the gas gravity and the temperature at atmospheric pressure. The effect of pressure on the enthalpy of natural gases is dependent upon the pressure-volume-temperature relationships,

Jan 1, 1945

By A. I. Johnson

This paper describes," the application, of a modular or building block approach to the analysis, design, and control of complex mineral treating processes. The main purpose of the paper is tutorial, to show the reader how such processes can be modeled using a modern digital computer" and, not to discuss in any detail the results that may be achieved in such studies. It is proposed that, the main techniques be illustrated by reference mainly to the Bayer process for alumina extraction and purification; in cooperation with the Aluminum Company of Canada Ltd. the author and his Colleagues at McMaster University and their students have studied this, process as a means of applying new computer techniques to extractive metallurgical processes. The plant described was studied by the author and his colleagues as a senior undergraduate project in cooperation with the Aluminum Company of Canada. It is one of several studies that have been carried out with Canadian industry. (1)

Jan 1, 1972

By Pierre Laliberté

Introduction ??Mine ventilation is a major consumer of power in underground mining, including air heating (winter) and air conditioning (deep mines). ??Any advances, including the development of low emission vehicles, that can improve underground air quality can reduce ventilation demand, and likewise reduce costs and energy consumption, including their associated greenhouse gas emissions.

Nov 1, 2011

By Charles E. Whieldon, C. I. Pierce

Data on the oilfields in Mahoning , Columbiana , Carroll , Jefferson , and Harrison Counties , Ohio , were collected from scattered sources and compiled to make the information readily available to operators who may be interested in conducting secondary - recovery operations in the area . General geology , oil production , oil - productive acreage , core data , reservoir calculations by townships , and miscellaneous data and reference material are presented .

Jan 1, 1965

This discussion of the paper of Chester W. Washburne should have been printed following the remarks of H. A. Wheeler, in Bulletin No. 100, April, 1915, pp. 835 and 836, but was inadvertently omitted. ROSWELL H. JOHNSON:-There is one reason why the hydrostatic interpretation of gas pressure is not wholly acceptable. As we go clown in the sands we seem to get excesses of gas. Particularly in this field it becomes excessive in quantity relative to the amount of water in the sand. If this holds in other fields as well it must mean that there has been an ascension of water, because these sedimentaries when laid down, were filled with connate water. If we do get an ascension of connate water, produced by some such phenomena as its expansion by heat or by the formation of new gas by pressure upon organic materials at great depth, we can hardly expect the pressure to be controlled merely hydrostatically. * In reply to Mr. Wheeler's inquiry as to gas wells with pressure higher than hydrostatic pressure, I would cite the original wells given by Orton on which he based the hydrostatic theory. He used in his calculation a head of 600 ft. above tide, assuming the outcrop of the Manitoulin Islands to be in Lake Superior, whereas the Trenton does not outcrop at Lake Superior. The Manitoulin Islands are in Lake Huron, the level of which is 580 ft. above tide. No allowance is made for the lower density of the fresher water near the outcrop, the weight taken for the whole column being the water of high density found at the wells.

Jan 5, 1915

This paper examines some of the important aspects of mineral taxation policies and practices, with reference to the mining tax regimes of selected Pacific Rim countries (see Tables 1 and 2). The following subjects are addressed:what is æmineral taxationÆ?, basis for mineral taxation, types of mineral taxes, objectives of the mineral taxation regime, best practices, and mineral royalties. Many countries, in some cases with the encouragement and assistance of international funding agencies, are actively assessing the international competitiveness of their mining tax regimes with a view to attracting investment. However, these countries recognise that the mining tax regime is not the only consideration that is taken into account by prospective investors. The countryÆs geological prospectivity, physical infrastructure, labour force, political risk, and regulatory system are also important factors in the investment decision making process. Although it is probably true that an attractive mining tax regime will not necessarily attract mineral investment, there is a real possibility that an unattractive regime can drive away investment. For example, Hugo Dummett, general manager for discovery at BHP, hinted recently that BHP could cease exploration in Russia in the absence of positive tax changes. Dummett is reported as saying that if taxes æend up being as onerous as they are now, we really have to rethink why we are hereÆ (Mining Journal, London, November 27, 1998).

Jan 1, 1999

By H. V. Flagg

OPERATION of a modern steel plant presents a curious anomaly. Large-scale operations, in which large volumes or heavy weights of materials are involved, are not usually subject to close control or narrow specifications. On the other hand, operations that call for a high degree of precision are usually carried out under carefully controlled conditions with delicate, precise machinery and tools, and production is made secondary to quality. In a modern steel mill both extremes are taken as a matter of course. A strip mill making auto-body sheets must supply its customers with sheets that all come within a tolerance of plus or minus 0.003 in. in gauge at any point from side to side or end to end, and without blemishes either of color or surface. Sheets that were considered par excellence as recently as ten years ago could not even find a market today. Such exacting requirements have made necessary a nicety of control that approaches the watchmaker's art. Notwithstanding this necessity for precision, the scale of operation is stupendous.

Jan 1, 1940

By Albert J. Rambosek

The results obtained in a study of the stress conditions existing in a drill bit-point area and in the underlying rock, when the bit was in full but nonpenetrative contact with the rock, are presented. This investigation by the Bureau of Mines was the preliminary exploratory phase of a long-range program of research on rock drilling to establish criteria for the maximum economically feasible rate of rock penetration. The photoelastic technique of experimental stress analysis was the principal method used to obtain the data. Transparent models and transmitted light were employed to investigate patterns in drill-bit models and isotropic materials under the bit when subjected to a concentrated static load. Comparative stress data for anisotropic rock were obtained by the reflective photoelastic technique. Brittle lacquer and an extensometer were used obtain supplementary information wherever substantiating data were desired to check photoelastic results. The zone of maximum shear occurs along an arc near the contact face of the bit. The stress distribution pattern in an isotropic model rock near the area contacted by the bit was nearly a mirror image of that exhibited within a similar areal zone of the bit. The stress pattern in granodiorite specimens was similar, though not symmetric, to the pattern in the isotropic model rock. The asymmetry of the stress pattern in the granodiorite was attributed to the anisotropic characteristics of the constituent minerals of various sizes.

Jan 1, 1963

By D. C. Martin, P. M. Hawley, C. P. Acott

"In bedded deposits such as coal or sedimentary iron, economic limits of mineable reserves are clearly defined by the footwall of the seams or ore-bearing units. Where open pits are developed in dipping strata, a long, high footwall slope may result. In many cases, unbenched slopes excavated along the base of the lowest mineable seam are operationally simple, economically desirable and geotechnicalty practical, although a variety of failure mechanisms may develop. This paper examines the engineering geology and rock mechanics parameters of importance in the design of footwall slopes. Possible failure mechanisms and stability analysis methods are described. Design considerations for benched and unbenched slopes are discussed with prime consideration given to development of long high stopes without benches or with a minimum number of benches. IntroductionIn bedded deposits, the ultimate depth and economic viability of an open pit in dipping strata may be controlled by the design of the footwall slope. The stability and, hence, design of footwall slopes is strongly influenced by the engineering geology and rock mechanics parameters of the slope forming materials. A clear understanding of the structural geology, engineering geology and tectonic history of the deposit is essential to assess the behaviour of the slope. This is particularly important for long high, unbenched footwall slopes such as shown in Photo I.A rational footwall slope design requires identification and assessment of all possible slope failure mechanisms with respect to the proposed slope geometry. Stability analyses of each potential failure mechanism are used to identify the main controls on slope stability and to develop appropriate slope design criteria. The optimum slope design is based on the most economic and geotechnically practical slope geometry with due consideration of operational constraints and of the possible advantages of specific remedial measures."

Jan 1, 1986

Two key elements in the design of a pastefill or high density backfill system are the preparation of the backfill material and its distribution underground. This paper examines these two areas. Owing to the essentially impervious nature of total mill tailings, preparation of pastefill and high density fill from current tailings involves a physical dewatering process. There are currently three methods available for this process: Vacuum or pressure filters. These represent the ætraditionalÆ approach to the preparation of pastefill. Paste production storage mechanism. This is a thickening/storage mechanism developed with the specific objective of producingpaste/high density backfills. Fluidization. This system utilises silos fitted with simple dewatering devices and nozzles. Recently developed by CANMET, it provides the simplest and most economical approach.This paper describes and compares the three preparation methods, from a practical and an economic point of view. Once the pastefill/high density fill has been prepared and binder added, the backfill must be distributed underground into the stopes. A fundamental factor in the design of a distribution system is the rheology of the material. No two materials will exhibit the same properties, and a sequence of rheological and related testing is required prior to the completion of the design of the underground distribution system. This paper covers the testwork normally required and discusses the fundamental design parameters of pastefill distribution systems. The final section of this paper summarises the use of pastefill at three mines in Canada.

Jan 1, 1998

By Guilherme Filipe de França Vieira

Os aços inoxidáveis ferríticos apresentam menor custo que os austeníticos, pois praticamente não possuem níquel em sua composição, e seu custo está diretamente ligado ao preço do níquel que possui alta volatilidade. Devido a sua capacidade de resistência à corrosão, estruturas são construídas a partir deste material e descartam a necessidade de revestimento contra corrosão. O trabalho tem como objetivo caracterizar o comportamento mecânico da liga de aço inoxidável ferrítico, UNS S43932. Metalografia e dureza foram realizadas para caracterizar o material e sua microestrutura. Por meio de ensaios mecânicos de tração, no equipamento MTS 250 kN, analisando sete corpos de prova, obtiveram-se propriedades como: módulo de elasticidade, tensão de escoamento, tensão limite de resistência à tração, tensão de ruptura, alongamento, redução de área, coeficiente de resistência e expoente de encruamento, através da curva monotônica. Pode-se observar que as propriedades mecânicas identificadas estão coerentes com aquelas fornecidas pelo fabricante, o que validou os ensaios e possibilitou a adicional obtenção de propriedades mecânicas referentes ao comportamento da parcela plástica.

Aug 16, 2017

New York Meets first Wednesday after first Tuesday of each month. DAVID H.-BROWNE, Chairman, JOHN H. JANEWAY, Vice-Chairman. F. E. PIERCE, Secretary, 35 Nassau St., New York, N. Y. P. A. MOSMAN, Treasurer. LEWIS W. FRANCIS. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. . ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston, Mass. ROBERT H. RICHARDS, ALBERT SAUVEUR. Columbia Holds four sessions during year. Annual meeting in September or October. FRANK A. ROSS, Chairman. RUSH J. WHITE, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P O. Drawer 2154, Spokane, Wash. FREDERIC KEFFER, FRANCIS A. THOMSON.

Jan 11, 1915

By Hector O. Romero, Paulo C. Fernández A, Christian Rees Prado, Claudio C. Gajardo

In open-pit mining, estimating post blasting displacement and spillage accurately is essential to guarantee operational efficiency, ensure alignment with production plans and their associated key performance indicators. The absence of predictive modeling tools on blasting operations results in several critical challenges, including operational reworks due to deviations in material displacement, significant discrepancies between mine and plant (ore grade dilution included), misalignment with the reported production plan, and increased operational costs due to inefficient use of resources. This study, conducted at Los Bronces Mine operated by Angloamerican, Chile, addresses the application of a three-dimensional simulation tool that, through numerical modeling, is capable of predicting post blast rock displacement. The implementation was carried out in a pit phase characterized by blasts near the pit boundaries, with a high risk of material spillage and potential blockage of the only access ramp to the extraction levels. By the integration of key design parameters, such as blast pattern geometry, detonating time, explosive charge distribution and pre and post blast survey, an optimal calibration was achieved and validated in seven blasting events to date, reaching an accuracy greater than 80% in estimating post-blast rock displacement and spillage volumes. Furthermore, this study allowed the evaluation of different pattern alternatives with and without spillage mitigation measures (use of air decks near the free face), obtaining a high correlation and accuracy exceeding 95% in predicting the selected design outcome, supporting optimal design selections. The result highlights the usefulness of the model as a decision-support tool for blasting engineers and short-term planning, by reducing the need for unnecessary operational reworks, improving geological and operational reconciliation, and ensuring the alignment of the extracting plan with production targets. The current average deviation is 15%, with higher deviations observed in blasts with smaller volumes of spill or where the simulated sequence was changed before blasting. The use of this type of three-dimensional numerical modeling represents a significant advancement for blast engineering and the optimization of key performance indicators in open-pit mining operations.

Jan 26, 2026

This symposium is dedicated to the lifetime achievements of Professor H.Y. Sohn. It covers the scientific fields, processing routes and investigation techniques in which Prof. Sohn has worked during his career and is based in the equally important three topical areas: Principles, Technologies, and Industrial practice. Professor Sohn was General Chair of the very first TMS Fall Extraction and Processing Symposium in 1983 in San Francisco which led to the Annual such symposia as this International symposium. Furthermore, the theme of that symposium was sulfide smelting, which is also included in this symposium. [ ] Professor Sohn was born in a beautiful dynastic capital Kaesung, Korea on August 21, 1941. He received his B.S. degree in 1962 from Seoul National University, M.Sc. in 1966 from the University of New Brunswick, Fredericton, N.B., Canada, and his Ph.D. degree in 1970 from theUniversity of California at Berkeley all in Chemical Engineering. After working as a Research Associate at the State University of New York at Buffalo and as a Research Engineer at Du Pont?s Engineering Technology Laboratory, Dr. Sohn joined the Department of Metallurgical Engineering at the University of Utah in 1974 and currently holds the ranks of Professor of Metallurgical Engineering and Adjunct Professor of Chemical Engineering.

Jan 1, 2006

By E. M. Hillary, D. F. Sangster

"Abstract - As a contribution to the World Minerals Geoscience Database Project, an index-level database comprising information on 142 SEDEX Pb-Zn deposits and occurrences was constructed in Microsoft Access 95 format. Although consisting of only basic information, the compilation, with full referencing of all data, is possibly the largest non-corporate SEDEX Pb-Zn database in the world. It thus provides an opportunity to make geoscience queries of SEDEX Pb-Zn deposits on a scale not previously available. This report provides a summary of the results of a few such queries both as a contribution to a better understanding of SEDEX lead-zinc deposits and as a demonstration of what even such a simple database can offer.During the compilation process, it became apparent that SEDEX Pb-Zn deposits could be assigned to one of the following three sub-types: Type 1 (53.5% of total) in which sulfide minerals are the only exhalative components; Type 2 (33.1%) in which the exhalative components are sulfides plus chert, siderite/ankerite, and/or barite; Type 3 (13.4%) which contains any components of Types 1 and 2 plus abundant iron-oxide minerals (commonly magnetite) and/or is associated with iron oxide-rich sedimentary rocks.Highlights of systematic queries of the database reveal that:1. a majority (84%) of the world’s SEDEX Pb-Zn deposits are not underlain by a discordant footwall feeder zone or vent complex;2. 63.6% of deposits occur in Proterozoic strata followed by a second peak in the Devonian (16.8%). Of those in the Proterozoic, 83% of Type 3 deposits occur in the Gondwanaland supercontinent, whereas only 42% of Type 2 and 39% of Type 1 are located in this large paleo-landmass;3. median (Pb+Zn) grades in Types 1 and 2 fall between 9% and 10% with a majority clustering within this range. Type 3 grades, however, range from ~1% to ~20% (Pb+Zn) with a median of 5%; 4. median size of Type 3 deposits is ~33 Mt, whereas Type 1 and 2 median sizes are ~7 Mt and ~8 Mt, respectively.The report concludes with a brief discussion of how an index-level database such as this can be used in conjunction with other, similar databases to reveal interesting and instructive relationships for guiding both research and exploration."

Jan 1, 1998