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By H. B. Brunot

On April 26, 1949, the Bureau first approved a machine designed to replace the cycle of cutting, blasting, and loading coal by a single operation. This machine took the coal directly from the solid face and delivered it to transportation equipment. By January 1, 1955, 30 approvals for designs of machines of this type had been granted by the Bureau. In the main, this paper describes briefly the action of the various designs approved as permissible. In addition, the approval number, the date of approval, the voltage of the power supply, the number and character of the explosion-proof accessory parts, the size of the trailing cable, and the overcurrent protection at the outby end of the trailing cable are given for each design. Since no similar information has been published by the Bureau, it is hoped the material in this paper will be valuable in giving the mining public an organized look at the various machines of this nature that have been approved as permissible by the Bureau.

Jan 1, 1956

By John H. Hild

"INTRODUCTION Alunite occurs within a radius of 10 miles of Marysvale, Piute County, Utah, in veins and as replacements of igneous rocks. A number of each type of deposit was explored by the Bureau of Mines, in cooperation with the Geological Survey, under the Strategic Minerals program during 1942. The exploratory work comprised geologic and topographic mapping, diamond drilling,,bulldozer and hand trenching, sinking test pits, rehabilitation of old workings, sampling alunite exposures, and constructing and repairing roads.ACKNOWLEDGNENTSIn its program of exploration of mineral deposits; the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches-are under the supervision of Dr. R. S. Dean, assistant director.With particular reference to this publication, acknowledgment is given to Richard E. Mieritz and William E. Young, who assisted on the project at various times; P. T. Allsman, chief. Salt Lake Division, Mining Branch, who advised on exploratory problems and gave valuable assistance in preparing the report and illustrations; A. P. T. Schumann, for preparing the illustrations; and to Gordon L. Bell, Max Willard, and Eugene Callaghan, of the Geological Survey, who cooperated as representatives of that agency."

Nov 1, 1946

By L. F. Heising

The Bureau of Mines evaluated 191 composites from the central Mesabi Range, Minn., chiefly by reductive roasting and magnetic separation. After reductive roasting and magnetic separation at minus 325 mesh, 28 composites produced concentrates that contained an average of 66.0 percent iron with less than 10 percent silica. Recovery of contained iron was over 90 percent. Natural magnetic material in excess of 5 percent was present in 142 composites. Trial flotation tests were used to evaluate three samples unresponsive to reductive roasting and magnetic separation procedures, and satisfactory concentrates having low silica contents (averaging 6.6 percent) were achieved.

Jan 1, 1965

By M. Grave

Rock Engineers are required to design safe cost effective support systems and stoping layouts for their respective mines. As each stope has its own unique environment, continual re evaluation is required in all stopes to maximize extraction and achieve value from the support standard. This paper presents numerical modelling used to plan early mining within the shaft pillar and a reevaluation of an existing stope support standard.

Jan 1, 2009

By H. W. Fleming

In 1955, the results of a regional, geological interpretation of the northern portion of New Brunswick were used as a basis for selecting, for intensive exploration, three areas in which structural and stratigraphic conditions were believed to be favourable. Airborne electromagnetic work, in one of these areas, provided the justification for acquiring the Murray group. Even though the initial results were discouraging, this geological interpretation, combined with the fortuitous discovery of cop• per-bearing float, was sufficient reason for carrying out further work using geochemical methods. This work finally resulted in the discovery of the Murray massive-sulphide deposit, after about eighteen months of coordinated exploration on the property. While this deposit is a typical New Brunswick-type base-metal occurrence, extensive leaching has produced a fossil gossan that rendered it an elusive target for exploration techniques of limited penetration Full credit for localizing the target area is given to the geochemical techniques, but geophysical surveys were needed to provide the necessary

Jan 1, 1961

By AIME

SUPPLEMENTING surveys of the engineering profession regarding salaries and advancement, based upon data from individual engineers, a survey through a questionnaire to employers of engineers has recently been made by a subcommittee of the Engineers Joint Council's Committee on the Economic Status of the Engineer. Its object was to learn directly from employers their attitudes and policies pertaining to the selection, training, placement, advancement, guidance, and professional activities of engineering graduate employes. The questionnaire was sent in May 1946 to 174 employers of engineers, including colleges. Replies were received from 104 employers in nineteen fields of industry, who employ about 2,000,000 persons, about 40,000 of whom are engineers. The following general observations are based on the questionnaires returned. Who Are Hired? Of the co-operators 96 per cent employ cadet engineers directly upon graduation from engineering schools, but only 4 per cent recruit their engineering staffs exclusively from the new graduates. About 43 per cent hire more than half of their new engineer employes after one or more years' experience with other employers. This is evidently a matter of necessity or expediency rather than preference, because more than sixty per cent of those reporting indicate that they prefer to hire the new graduate.

Jan 1, 1947

By Philip Arthur

The ISASMELT process is making a significant contribution to the global metals industry. ISASMELT furnaces are now operating successfully in eight different countries and treating approximately 3 million tonnes of concentrates and secondary materials per year. The process is currently used in both lead and copper smelting. The most recently commissioned plants were in Germany and China, one for treating scrap copper and the other treating low-grade copper concentrates. The Copper ISASMEL T furnace ("CIF") at Mount Isa Mines Limited ("MIM") has continued to set new operational records, with throughput of more than I million tonnes of concentrate per year and very low operating costs. This paper summarises the latest operational data from the Mount Isa Copper ISASMELT plant and outlines the successful approach to industrial R&D taken by MIM in the development of the ISASMEL T process.

Jan 1, 2003

By J. E. Nesset

"This paper discusses the importance of considering residence time distribution (RTD) in the design of flotation and mixing circuits and in the analysis of operating problems. The experiences and successes of Brunswick Mining in this area are covered and include: the development of a practical RTD measurement technique using pulp conductivity, baffle installation to improve the RTD of existing process equipment, and the method in which RTD considerations have been used to design the newest flotation and conditioning operations IntroductionThe use of residence time distributions (RTDs) in the design and analysis of unit operations is well understood by the chemical engineering profession in while mineral processing engineers have tended to rely on empirical and rule-of-thumb factors. For example, in scale up from laboratory and pilot test results to full size flotation plant design, empirical rule s are often used to establish residence time and number of cells in the bank. Coleman suggests a factor of at least 2, and up to 5 for gold ores, be applied to laboratory determined flotation times. This is further illustrated in Table I, taken from Denver equipment. The number of cells in series to achieve the required retention time while minimizing short-circuiting has generated a variety of conclusions (Table 2). Obviously there is less than complete agreement on the subject. Young notes that a clear difference of opinion has emerged and cites as extremes, (i) the publications of Outokumpum showing unimpaired recovery for its largest machines (38 m3) compared to equivalent retention times for numerous smaller machines, and (ii) the experiences of Eastern European countries where the practice is to install banks of 30 unit s or more, operating in series, often with unit retention times of only a fraction of a minute.The empirical factors used by engineers presumably account for other than tested feed conditions, inefficiencies in large continuous machines, inevitable day-to-day circuit disruptions, gradual equipment deterioration and any other safety factor the engineer feels compelled to incorporate. An understanding of RTD concepts and techniques should help the practicing mineral engineer to develop more soundly based factors. Thi s paper relates the experiences of Brunswick Mining in using RTD techniques in the unit operations of flot ation and mixing"

Jan 1, 1988

By J. E. Nesset

"This paper discusses the importance of considering residence time distribution (RTD) in the design of flotation and mixing circuits and in the analysis of operating problems. The experiences and successes of Brunswick Mining in this area are covered and include: the development of a practical RTD measurement technique using pulp conductivity, baffle installation to improve the RTD of existing process equipment, and the method in which RTD considerations have been used to design the newest flotation and conditioning operations. IntroductionThe use of residence time distributions (RTDs) in the design and analysis of unit operations is well understood by the chemical engineering profession in while mineral processing engineers have tended to rely on empirical and rule-of-thumb factors. For example, in scale up from laboratory and pilot test results to full size flotation plant design, empirical rule s are often used to establish residence time and number of cells in the bank. Coleman suggests a factor of at least 2, and up to 5 for gold ores, be applied to laboratory determined flotation times. This is further illustrated in Table I, taken from Denver equipment.The number of cells in series to achieve the required retention time while minimizing short-circuiting has generated a variety of conclusions (Table 2). Obviously there is less than complete agreement on the subject. Young notes that a clear difference of opinion has emerged and cites as extremes, (i) the publications of Outokumpum showing unimpaired recovery for its largest machines (38 m3) compared to equivalent retention times for numerous smaller machines, and (ii) the experiences of Eastern European countries where the practice is to install banks of 30 unit s or more, operating in series, often with unit retention times of only a fraction of a minute.The empirical factors used by engineers presumably account for other than tested feed conditions, inefficiencies in large continuous machines, inevitable day-to-day circuit disruptions, gradual equipment deterioration and any other safety factor the engineer feels compelled to incorporate. An understanding of RTD concepts and techniques should help the practicing mineral engineer to develop more soundly based factors. This paper relates the experiences of Brunswick Mining in using RTD techniques in the unit operations of flotation and mixing."

Jan 1, 1988

By Richard N. Spencer

"El surgimiento de los laboratorios combinados del Banco Minero del Perú en la industria minera facilitó las investigaciones y tratamientos en la composición de los minerales. Por tal motivo, el objeto del presente texto es remarcar la función del laboratorio químico del Banco Minero del Perú, en tanto le suministre información analítica y compleja sobre el campo mineral inorgánico, asi como garantice los resultados analíticos uniformes con la más alta calidad. Asimismo la disposición de dicha entidad química, abarca las compras del Banco Minero, plantas de beneficio del Banco Minero y el control químico requerido por las nuevas unidades de los laboratorios Metalúrgico y Petrográfico que son parte integrante de este Laboratorio Central. En este punto,el laboratorio petrográfico, como fuente permanente de información básica ayuda al geólogo o metalurgista y planifica mejor la función del laboratorio central, mientras que el metalúrgico, desarrolla pruebas de molienda de minerales, flotación mecánica y no mecánica, y pruebas de concentración por gravedad. Posteriormente están las secciones de recepción, trituración y muestreo del laboratorio, las cuales se componen del departamento de trituración, departamento de muestreo y departamento de archivo, respectivamente. Finalmente, este equipo de laboratorio, cuenta con un laboratorio de Microscopia, de preparación de muestras para el examen microscópico yde ensayos especiales, que en conjunto permiten un mejor tratamiento y descripción sobre los minerales a investigar."

Jul 20, 1956

By J. Marbeau

In this paper, a geostatistical study of the North Butte roll type uranium deposit is presented. The geostatistical procedure applied takes into account the varying direction of the roll front for reserves calculations. For variogram calculation, the roll front is unfolded thereby allowing estimation of the variogram in directions parallel to and perpendicular to the roll front. Variograms calculated in unfolded space show strong directional anisotropies consistent with the anticipated configuration of the deposit.

Jan 1, 1991

By T. A. Henrie

One objective of Project Gnome is to study the feasibility of a phase of the Plowshare program recovering thermal energy from an underground nuclear explosion. The test will be conducted in an underground salt deposit. It is anticipated that some of the energy thus released will be stored as thermal energy in molten salt. This report describes the pre-Gnome experiments conducted at the Federal Bureau of Mines Metallurgy Research Laboratory, Boulder City, Nev. The objectives of this study were to determine the problems involved in the recovery of thermal energy from molten salts to assist in planning the experimental program for the Gnome project.

Jan 1, 1961

By Fabrício Domith Rodrigues, Marcelo Moreira Furst Gonçalves, Leonardo José Silva de Oliveira, Luiz Fernando Andrade de Castro

Eventualmente é necessário ajustar a largura de placas via processo de oxicorte. Contudo, o processo de corte convencional a frio não é recomendado para algumas qualidades de aço por gerar susceptibilidades às trincas na seção de corte. Para contornar a ocorrência de trincas no corte convencional foi desenvolvida e aplicada na Usiminas uma nova técnica de oxicorte em placas com base na utilização de duplo maçarico. Após otimização dos parâmetros de velocidade e posição dos maçaricos foi possível obter temperaturas da ordem de 200°C, homogeneamente distribuídas ao longo da seção de corte, favorecendo o ajuste dimensional sem trincas. Com a implementação industrial, verificou-se índices superiores a 85% de aprovação de placas e, consequentemente, o aproveitamento de placas que anteriormente não eram destinadas a geração de produtos laminados.

Oct 1, 2019

By S Lakemond, L I. Ku, J Vaughan

Conventional processing of poly-metallic gold containing flotation concentrates are challenging for a number of reasons. One reason is that substantial copper and zinc in the cyanide leach solution compete with gold and silver for carbon adsorption sites. In this study, metal-cyanide adsorption kinetics and equilibrium are measured on three samples of coconut derived activated carbon and one sample of synthetic carbon. Loading selectivity was confirmed to be in the order gold>silver>copper>zinc for all carbon samples. The synthetic carbon tested showed promising results in terms of loading kinetics and capacity for precious metals.CITATION:Lakemond, S, Ku, L I and Vaughan, J, 2013. Effect of carbon type on adsorption of Cu, Zn, Ag and Au from mixed cyanide solution, in Proceedings World Gold 2013 , pp 411-418 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By F. Benard

Recovery of selenium and tellurium at Copper Cliff by the Ontario Refining Co. has been previously described by the writer.l During 1935 a new building was erected to house this operation and description of the new plant and process form the subject of this paper. The building, of modern steel and tile construction, covers an area of 5900 sq. ft. with a volume of approximately 165,000 cu. ft. The large monitored center bay is flanked by two smaller outside bays, one of which is devoted to the tellurium section. All equipment, ceilings and upper walls, are treated with aluminum paint, giving good illumination and facilitating good housekeeping, essential from a health standpoint in handling material of this nature. Equipment Layout and type of equipment conforms to the requirements of the process as described below. In the selenium section, storage tanks, neutralizing tanks and precipitators are of steel construction, lead-lined and arranged for gravity flow (Fig. 1). The neutralizing tanks are equipped with water-cooled lead coils for controlling solution temperature, agitation being accomplished with compressed air. The precipitators are provided with mechanical agitators, and sulphur dioxide is introduced into the solution through 1/2-in. lead pipes leading from a manifold attached to the cover of the precipitator. Each precipitator has internal cooling coils and an air-jet exhauster to carry off fumes. Neutralized solutions are filtered in a 29-plate wooden filter press using heavy cotton duck as a filter medium, forced feed being maintained by a Welmet centrifugal pump. Dilute solutions are concentrated by evaporation in a vacuum evaporator, constructed of cast hard lead. Heat is supplied by an outside steam chest operating under 15 Ib. steam pressure. The solution is circulated through the steam chest by a pump of antimoniallead at a rate approximating 400 cu. ft. per min. The evaporator is evacuated by a water-jet condenser that creates a vacuum of 26 in. of mercury under normal operating conditions. The capacity of the vessel is 60 cu. ft. and the rate of evaporation 25 cu. ft. per hour.

Jan 1, 1944

High-pressure grinding rolls (HPGR) are an accepted, but continuously expanding, comminution technology. The copper industry has a growing need to process harder ores with progressively lower grades, more challenging metallurgy and increasing demand for efficient bacterial leaching applications. This has resulted in a major focus on HPGR use in a crushing circuit. If the industry is to increase leach extraction while lowering energy costs in high-throughput hydrometallurgical operations, HPGR will be of inherent significance. The following paper summarizes test work on copper leach ores utilizing the benefits of HPGR comminution, while increasing several critical metallurgical parameters. Based on the current work and previous investigations, it was found that HPGR comminution within a crushing circuit, in specific instances, can result in 2 - >10% increases in cop-per extraction. The tested variables are crush size, rock type and copper mineralogy dependence. Various other process parameters may also be optimized.

Jan 1, 2011

By D. Harrington, W. J. Fene

That fatalities from mine explosions can be very much reduced from the experience of past years if not wholly eliminated was fairly well demonstrated during the fiscal year ended June 30 , 1934 , there being only 28 deaths in the United States from explosions during this period . This is by far the lowest number of fatalities from explosions in the history of coal mining in the United States insofar as records are available . Although the frequency of occurrence of explosions has not decreased greatly during the past 6 years , there has been a marked decrease in severity , indicating that our coal -mining people are taking more effective precautions to prevent the spread of explosions . Pennsylvania is a good example of what may be done in reducing both the frequency and the severity of explosions ; by the adoption of up- to - date safety measures , Pennsylvania bituminous mines now have the enviable record of only one major explosion disaster in more than 5 years , and the one major explosion which did occur cost but 7 lives although 277 persons were exposed ; their lives were saved because rock- dusting prevented the spread of the flame and violence . Many of our other mining States are making definite progress in working mines without disastrous explosions and fires ; some of these , like Alabama , West Virginia , Indiana , Wyoming, and others now operating with few , if any , explosions , have had anything but a favorable record in the past .

Jan 1, 1935

By Nilmara Dias, Maria Margarida Martins, Maria Teresa Carvalho

"The heavy residual fraction of the mechanical and biological treatment (MBT) plants treating undifferentiated municipal solid waste is mostly composed by inert materials, such as glass, stones, ceramics and brick. Glass, appearing in significant grade and amount, is not recycled today due to the high content in the other materials, mainly stones. All these materials have approximately the same density but stones have significantly different shape from other materials particles. In this paper it is presented the research developed to eliminate stones appearing in the fine fraction (2.8-8 mm) of the MBT plants heavy residual fraction (MBTr) using a shaking table operated in dry conditions. Two different samples from two different MBT plants were used. Firstly, the samples were characterized (materials content and particle size analysis). Then, laboratory work was carried out to optimize the operation of the shaking table, by changing the machine parameters, deck slope and movement frequency. The study showed that it is possible to upgrade the product in glass. The best results, obtained with one single stage of processing, were 82% content in glass with 84% in recovery, in the glass concentrate, when the coarser fraction (-8+5.6 mm) of one of the MBT plants was used. With the intermediate particle size fraction (-5.6 + 4mm), the glass concentrate attained 74% content in glass with 91% recovery."

Jan 1, 2014

Gas dynamic phenomena, particularly instantaneous outbursts of coal and gas are problems experienced in gassy, highly stressed coal, both usually the result of depth. Diff- erent mining geometries present different opportunities for seam gas to escape, starting from the virgin condition unaffected by mining and ending with the mining of the coal. The mining of the coal varies from entering a virgin seam cross-measure, heading out into virgin seam, advancing longwall faces into virgin seam and extracting developed blocks from large longwall retreating blocks to small pillars. Each method has its particular gass- iness patterns and particular stress patterns, both changing to some extent with time, and changing as mining progresses. Geological structural anomalies are the cause of gas and stress anomalies, causing in turn greater gas and stress manifestations. Pre-drainage of gas from the working seam not only degasifies the coal but causes it to shrink and so may affect stress as well as gas patterns. Unfortunately prior degasification is not all benefit, and there are some d13- advantages to its use. Also although it is possible to degasify places ahead, gassiness will return if drainage holes are shut down or sealed up and other deleterious aspects may be induced. Research should continue into the problem of instantaneous outbursts of coal and Gas.

Jan 1, 1986

By S. T. Johansen, B. T. Løvfall, T. Rodriguez Duran

In this paper we develop a physics-based model for lining erosion in steel ladles. The model predicts the temperature evolution in the liquid slag, steel, refractory bricks, and outer steel shell of the ladle. The flow of slag and steel is due to forced convection induced by inert gas injection, vacuum treatment (extreme bubble expansion), natural convection, and waves caused by the gas stirring. The lining erosion takes place by dissolution of refractory elements into the steel or slag. The mass and heat transfer coefficients inside the ladle during gas stirring are modelled based on wall functions which take the distribution of wall shear velocities as a critical input. The wall shear velocities are obtained from computational fluid dynamics (CFD) simulations for a sample of scenarios, spanning out the operational space, and a model is developed using curve fitting. The model is capable of reproducing both thermal and erosion evolution well. Deviations between model predictions and industrial data are discussed. The model is fast and has been tested successfully in a ‘semi-online’ application. The model source code is available to the public at [https://github.com/SINTEF/refractorywear].

Apr 16, 2024