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By Garnet T. Page

"ABSTRACTThese societies •can help in such aspects of a vocation.al guidance program in secondary schools as: provide vocational and technical information, and assist with vocational exploration, such .as plant visits, films, etc. -as .an aid to the student in making a self-inventory. Evidence is increasing that employers' needs for engineers and scientists will not be adequately met in the future. Therefore, the E.I.C., C.I.M., .and C.I:C. recently revised and extended the activities of the Canadian Counselling Committee on Engineering and Science. This co-•operative .action is to be integrated with the educational system, nationally .and locally, and with provincial associations •of engineers and other groups interested in the provision of vocational information in engineering and science.DEFINITIONTHE scientific treatment of any subject requires consistent use of carefully defined terms. The National Vocational Guidance Association of the United States studied the problem of the definition of vocational guidance for .about 16 years, and in 1937 finally arrived at:""Vocational guidance is the pro-cess of assisting the individual to choose an occupation, prepare for it, enter upon and progress in it. It is concerned primarily with helping individuals make decisions and choices involved in planning a future and building a career -decisions and choices necessary in effecting satisfactory vocational adjustment.""RANGEAs a school enterprise, vocational guidance begins at that point in the individual's life when he finds it necessary to make choices that have a definite significance for his future vocation."

Jan 1, 1952

By Diana Pérez Escobar

O efeito do caminho de solidificação de um aço High Temperature Processing (HTP) API 5L X65 com 0,09 %Nb, 0,039%C e 0,54% Mn (percentagem em massa) na segregação, microestrutura e distribuição dos precipitados de Ti,Nb(C,N) foi estudado por microscopia ótica, eletrônica de varredura (MEV) e simulação computacional (ThermoCalc e DICTRA). Os resultados foram comparados com os de um aço microligado comercial com 0,04 %Nb, 0,09%C e 0,97 %Mn. Foi encontrado que o principal parâmetro que influencia no caminho de solidificação é o teor de C, o que está de acordo com a maior micro e macrossegregação observada no aço microligado comercial, em comparação ao aço HTP.

Oct 30, 2017

By Tiago Bristt Gonoring

Neste trabalho foi avaliado o efeito da adição de metano e argônio sobre a redução a plasma de pós de hematita de alta pureza (com %Fe2O3> 99,00 e tamanho de partículas

Aug 8, 2018

By E. E. Ungar

The ways in which noise is generated and radiated by chutes and screens are described and corresponding noise control concepts are discussed. The amounts of noise reduction produced by applicable noise control means are delineated and generally cost-effective means are recommended. Available noise control materials and their applications are discussed. The results of field measurements, laboratory experiments, theoretical analyses, and studies of data provided by suppliers are summarized.

Jan 1, 1975

By Franz Ramstorfer

Impressões de Baumann são utilizadas amplamente nas aciarias para a avaliação e monitoramento da qualidade interna de placas: em particular a segregação central. A análise e monitoramento da segregação central é uma base importante do monitoramento da condição da máquina de lingotamento contínuo, da otimização dos parâmetros do processo de lingotamento contínuo e da qualidade das placas. Em geral, o tipo e a intensidade da segregação central são determinados através da comparação da imagem real com imagens de referência do padrão aplicado. O presente trabalho foi focado no desenvolvimento de uma ferramenta de análise computacional, precisa e fácil de usar pelos operadores do laboratório de Baumann. O objetivo foi estabelecer uma base padronizada e confiável para o processo de monitoramento da segregação central. A metodologia desenvolvida é baseada em processamento de imagem computacional de uma impressão de Baumann em tons de cinza. Observou-se que a classificação de segregação pode ser realizada com uma precisão excelente através da análise computacional dos dados de imagem da segregação central. O procedimento de classificação foi implementado com a utilização de uma rede neural feed forward.

Jul 29, 2018

By R. Ghomashchi

Wear, fatigue and corrosion are the most widely encountered modes of failure in materials used in engineering applications, including aero-gas turbines. Although wear is distinctly classified as adhesive, abrasive, erosive, fretting and so on, there are usually more than one wear mechanism involved in the failure of components in service because there are many systems and materials variables active in materials wear that makes it more difficult to study. This is further complicated by the discrepancies between the results of laboratory tests and field data. The present investigation was set up to examine the wear characteristics of M50 and T1 high-speed steels at both room and elevated temperatures to draw a thorough understanding of the wear behavior of this class of high-speed steels. This article focuses on the mechanical and microstructural characterization of wear for T1 and M50 high-speed steels using a pin-on-disk wear machine.

Jan 1, 2005

By Brunno Spinelli Pimentel

Ambientes contendo H2S e CO2 impõem condições severas a componentes fabricados em aços, já que estes podem sofrer corrosão com perda de propriedades mecânicas e falha das instalações. Uma preocupação é a quantificação dos fenômenos envolvendo difusão do hidrogênio atômico, o qual (seja pelo gás H2 em interfaces ou pela interação com ligações atômicas ou discordâncias) pode causar redução nas energias superficiais de fraturamento prejudicando ductilidade e tenacidade. Neste cenário, este trabalho investiga a fragilização por hidrogênio em um aço microligado API 5L X65 sour obtido de um tubo de diâmetro externo 32” e espessura de parede 20,6 mm fabricado pelo processo UOE. Amostras longitudinais e transversais de tração (ASTM E8/E8M) foram extraídas e imersas em solução saturada com H2S. O eletrólito empregado foi a solução A (ácido acético contendo cloreto de sódio) da norma NACE TM0284-2011, fazendo-se purga com N2 e injeções de H2S. Os tempos de imersão foram de 0, 96 e 360 horas, sendo os ensaios de tração realizados após doze dias do término da imersão. Os resultados não revelaram efeito estatisticamente relevante na resistência mecânica, na evolução tensão-deformação e tampouco no módulo de tenacidade. Entretanto, foi observado maior espalhamento dos resultados advindos de amostras submetidas a H2S. Esse comportamento sugere que o hidrogênio influenciou no micromecanismo local de fraturamento, mas com inexpressivo comprometimento das propriedades monotônicas macroscópicas. Tal desempenho pode ser fruto da microestrutura com grãos refinados e do baixo nível de inclusões encontrado, indicando poucos e uniformes sítios de ancoramento de hidrogênio irreversível.

Aug 8, 2018

By Robert Bachus, Nikolaos Machairasm, Allen Cadden

Data Interchange for Geotechnical and Geoenvironmental Specialists (DIGGS) is a data transfer standard that is gaining widespread acceptance in the geotechnical and geoenvironmental communities. Originally developed using funding from the Federal Highway Administration (FHWA) to efficiently capture data related to geotechnical boring logs, cone penetration test (CPT) soundings, and lab testing results, the data transfer protocol is rapidly gaining traction. It has been shown to have beneficial impacts in other allied areas where disparate parties (i.e., consultants, contractors, vendors, etc.) routinely publish/submit data as part of project deliverables. The historic problem is that many of these submissions use paper copies (i.e., .pdf images) to transmit valuable data for the project… data that may extend beyond the “technical” aspects of the project (e.g., equipment operating conditions, construction production rates, project costs, etc.). These data could be used by multiple parties to assess project performance and safety, as well as to track productivity, etc. Currently, in the limited situations when actual data are compiled and transmitted, the data often are submitted as an author-specific (and often proprietary) software application and must then be re-entered into other software applications (e.g., analysis software, database, etc.) for use beyond simple data collection. An initiative undertaken by the Geo-Institute (G-I) of the American Society of Civil Engineers (ASCE) focuses on exploiting the full potential of DIGGS to geoprofessionals both within and outside of the transportation community. The deep foundations industry represents one community that could benefit significantly from using DIGGS. Data of interest to DFI members include production records, quality assurance information (e.g., verticality and alignment, concrete strength), and, importantly, load test results. When adopting DIGGS, users need not modify how they capture data, but rather will use DIGGS as a vehicle to transfer data to other applications in a standard format where it can be shared, used, stored, and retrieved. This paper and associated presentation will describe DIGGS and demonstrate how DIGGS can be used effectively within the deep foundations community.

Jan 1, 2019

An Environmental Impact Statement (EIS) for a major mining development typically has to address various aspects of surface water management, including some which generally tend to be the more contentious: the diversion of rivers and creeks from areas disturbed by mining, and their rehabilitation; the effective management of disturbed area run-off via the collection, containment and treatment of contaminated water on site in sedimentation dams; the collection, containment and treatment of mine pit water; the decommissioning of surface water storages; final void water quality; and water discharge criteria. Environmental Impact Assessment processes for proposed mining developments in Australia at the state and commonwealth level usually involve a form of Initial Advice Statement (or Notice of Intent), Terms of Reference, an EIS, and a Supplementary Report (or similar) which responds to agency and public comment on the EIS. The EIS is used by approval agencies to decide the acceptability of the Project, and to set the conditions of approval. The conditions are often in the form of a state-issued æOperational LicenceÆ or similar. With mining, the initial approval at the EIS stage is often just a pre-cursor to various other planning related approvals, including obtaining a mining lease. Afterwards, mine plans and plans of operations must be submitted to government at various stages of the mineÆs life, ostensibly to provide the detailed mine planning over periods of one û five years. Despite all this additional planning and documentation beyond the submission of the EIS, government approval agencies are increasingly not satisfied with conceptual water management designs and commitments to an outcome (such as meeting a specified water quality standard) in the EIS. Agencies are also requiring sufficient water management design information to be convinced that the outcomes are achievable. To assist proponents of major mining developments, the Queensland Government has published Technical Guidelines for water management, and Environment Australia has published a æBest Practice Environmental Management in MiningÆ booklet on water management. In addition, the Australian and New Zealand Environment and Conservation Council (ANZECC. 2000) has published Water Quality Guidelines which provide an approach to water management, and provide receiving water investigation trigger criteria. So, what are the water management issues that are likely to be the subject of comment, debate and negotiation prior to the EIS being approved? and what commitments may a mining proponent have to make in order to convince the approval agencies that sufficient investigation and design has been provided? This paper provides some answers to this question, by reference to recent major mining proposals which the author has managed through state and commonwealth Environmental Impact Assessment processes.

Jan 1, 2003

An evaluation of blasting procedures in surface mining operations was undertaken to determine means for improving safety. The objectives of the study were to: 1. Develop guidelines for safer blasting practices 2. Specify changes or additions in regulations concerning the use of explosives 3. Identify areas in which additional knowledge needs to be developed. As a basis for the evaluation, an idealized blasting cycle was prepared. Developed in the form of a scenario of surface mining operations, this synthesis of good mining practices served as the standard against which observed activities were compared. Blasting hazards were divided into two categories: those known to exist and those which are potential. Known hazards were identified in terms of situations which have actually resulted in explosives-related accidents. The evidence for known hazards was obtained primarily from MESA records of mine accidents. Potential hazards were identified by observation of mining activities and consultations with mining, explosive industry and government regulatory agency personnel.

Jan 1, 1977

By Mônica Aline Magalhães Gurgel

Nas últimas décadas o setor siderúrgico vem desenvolvendo aços com maior valor tecnológico, surgindo assim várias classes, entre elas os aços avançados de alta resistência, onde encontra-se o aço bifásico ou “Dual Phase” (DP). Este aço é caracterizado por uma microestrutura ferrítica-martensítica, associada a uma matriz ferrítica com ilhas dispersas de martensita. Neste trabalho utilizou-se amostras de um aço baixo C e Mn, com micro adição de Nb e Mo, em desenvolvimento, onde se propôs uma avaliação da evolução microestrutural e propriedades mecânicas das amostras extraídas após a laminação a quente, a frio, seguida de recozimento intercrítico, em escala laboratorial, com auxílio de forno Mufla e um equipamento de análise termomecânica (TMA), resultando em taxas de aquecimento distintas, onde selecionou 7 temperaturas de encharque distintas e subsequente resfriamento com patamar isotérmico a 600°C por 20 minutos, onde observou-se que para esse ciclo a microestrutura com aspectos mais característicos de um DP se deu em tratamentos com temperatura de encharque entre 760 e 800°C.

Aug 17, 2017

By Afshin Sadri

Uma das principais razões para o reparo de altos-fornos é a perda do revestimento refratário, principalmente nas regiões da soleira e onde são feitos os furos de corrida. A operação intensa dos altos-fornos pode resultar em desgaste e deteorização extensiva do material refratário. Isto pode, então, afetar a continuidade das operações e a vida útil do forno. Novo-Lipetsk (NLMK) e a Hatch desenvolveram uma abordagem sistemática para monitorar a condição do revestimento da soleira dos altos-fornos usando Acousto Ultrasonic-Eco (AU-E), um sistema de ensaios não-destrutivos desenvolvido pela Hatch. Inspeções contínuas e periódicas dos altos-fornos revelaram áreas com deterioração acelerada do material refratário, formação extensa de “elefant foot” e acelerado desgaste do refratário, assim como fissuras e outras anomalias. Para prolongar a vida do forno, mantendo a intensidade de suas operações, algumas modificações, tais como a melhoria da qualidade do coque e da limpeza das placas de resfriamento e adição de óxido de titânio, entre outras medidas, foram recomendadas e aplicadas. Este trabalho demonstra como esforços coordenados entre a NLMK e a Hatch resultaram no prolongamento da vida útil de um alto-forno

Aug 17, 2017

By R. L. Brown

This report, summarizing the Bureau of Mines research and technologic work on coal and coal products for the period July 1, 1950, to July 1, 1951, is based largely on publications issued during the year. The sixteenth in an annual series, it gives footnote references to publications giving further details of the research and technologic work described, except in a few cases where research data presented herein has not been published previously. During the year, the national fuels situation was generally one of plentiful supply.3/ Mineral-fuel resources appeared adequate for several hundred years at reasonably increasing rates of supply. Coal-production capacity was in excess of demand; petroleum supplies were adequate; and natural gas use was limited only by pipeline capacity. However, it was pointed out that a world war would drastically change this situation of relative plenty, particularly with regard to supplies of petroleum and its products. Conversion to the use of coal on a large scale would be required, and improved methods of mining and of processing and using coal in solid or fluidized form or converted to liquid fuels could materially contribute to our national safety.

Jan 1, 1952

By Regis Antonio Albertassi Tavares

O presente trabalho propôs-se avaliar a potencialidade de obtenção de uma microestrutura dual phase em um aço baixo carbono com microadição de molibdênio e nióbio, laminado a frio Full Hard. Os estudos foram suportados pelas análises da recristalização da ferrita, da fração volumétrica de austenita formada e sua evolução composicional/estrutural em função da temperatura de encharque no intervalo do campo intercrítico durante o encharque no tratamento térmico proposto com resfriamento em salmoura – a fim de simular o encharque no recozimento contínuo. As caracterizações microestruturais e mecânicas foram avaliadas por Microscopia Ótica, Microscopia Eletrônica de Varredura (MEV), Dilatometria e ensaios de dureza Vickers, e confrontadas com estudos prévios via Espectroscopia de Raios-X de Dispersão de Energia (EDS).

Aug 7, 2018

By C. Edwards

ABSTRACT The versatility and specificity of rare earth elements (REEs) have led to their use in an everincreasing variety of applications in new technologies; consequently, demand for REEs has increased significantly. However, separating REEs safely and effectively is a complex and expensive process. This paper presents a review of REE mineral processing technologies, providing an update on current capabilities in REE mineral processing and REE extraction from the major commercially valuable REEbearing minerals such as bastnaesite, monazite, and xenotime, as well as the ion-absorption type of REE deposits.

Jan 1, 2013

By R. H. Sergent

The interest in using halogens for extracting precious metals from ores has increased due to changes In ore characteristics, environmental concerns and regulations. The rediscovery of halogen leaching capability has been the topic of these and other writers1-30. Much work has been done on the performance of bromine, chlorine and iodine5-29. Of these, bromine and chlorine look most promising. Iodine is quite expensive and sometimes forms an Insoluble film on a precious metal surface22,23. Little experimental work has been published on the relative performance of bromine versus chlorine. The Pourbaix diagrams for the halide leach system (see Fig. 1-4) Indicates a significant stability advantage for bromine In forming complex ions with gold. This should result In greater extraction of gold under similar leach conditions and Is evaluated In this work. The regeneration of halogen from a spent leech solution is a critical requirement for an environmentally acceptable halogen leach process. Bromide can be oxidized In-situ to bromine ~ adding chlorine or ozone2,31. Bromide like chloride can be oxidized In an electrochemical cell to produce halogen on demand 13,15,17. Bromine clearly offers a number of possible regeneration pathways. This work strives to compare the relative ability of chlorine and bromine to extract gold from partially and fully oxidized ores. A commercially pressure oxidized sample was evaluated under a number of experimental conditions. The autoclave feed ore from the same mill was also evaluated after complete oxidation In a laboratory autoclave.

Jan 1, 1993

By E. Engelbrecht

"A pressure non-oxidative leach is employed at Anglo American Platinum Base Metal Refiners to extract nickel from a slow cooled matte. The design base requires two 80 m3 autoclaves in parallel to achieve a nickel extraction of 60% at the nameplate capacity of 32.4 ktpa nickel plated. Isothermal modelling of mineralogical and chemical concentration profiles, through a reactive mass balance, permitted rate constant parameter estimation and selection of the most probable reaction pathway. The model was validated with plant data up to a capacity of 26 ktpa Ni plated and suggested by extrapolation that nameplate capacity may be viable through one 80 m3 autoclave.INTRODUCTION Anglo American Platinum Base Metal Refiners is situated on the outskirts of Rustenburg in the North-West province of South-Africa. The refinery produces nickel cathode, copper cathode, cobalt sulphate powder, covellite rich copper pressure leach residue and bulk sodium sulphate through an integrated circuit that refines slow cooled converter matte. The converter matte is milled, non-magnetics are separated as solid nickel copper matte (NCM), and the magnetics are leached yielding a pressure vessel liquor (PVL). The remaining solid platinum group metals (PGM) concentrate after leaching is sent for downstream processing in the Precious Metals Refinery (Hofirek & Kerfoot, 1992). The work presented here is applicable to the base metals refinery which receives the two base metals feed stocks NCM and PVL. In 2009 the capacity of the refinery was upgraded from 21 ktpa nickel cathode plated to 32.4 ktpa. This paper deals with evaluating the capacity of the pressurised non-oxidative nickel leach (NOX) process which accounts for at least 28% of the nickel leached from NCM by design. The NOX design base requires two 80 m3 autoclaves divided into four compartments operated in parallel at 155°C and 600kPa(g). Elevated temperature is required to speed up the leach kinetics of particularly nickel and iron which are trapped in slow leaching mineralogical phases namely millerite and bornite, (Dinham, 2006). The stated equivalent capacity for the NOX configuration was 32.9 ktpa nickel plated at first pass nickel and iron leach efficiencies of 60% and above 80% respectively and is a key step for the selective removal of iron (Bryson, Hofirek, Collins, Stiksma, & Bereaowsky, 2008)."

Jan 1, 2017

By J Jackson, M F. Young

"Ore is the economic portion of a mineral deposit that can be extracted economically. Hence an ore type is a classification of the ore based on one or more dominant characteristics in order to enable communication between unit operations and/or technical disciplines.In project evaluation, ore types are often defined early based on geological observations by geologists and initial metallurgical testing is based around this classification even though a number of processing options can be under evaluation. However, the geological drivers of performance for each of these processes can be very different and the ore type classification for one process may not be relevant for another. In operations an ore type, as either defined in the project evaluation phase or those that evolve with additional knowledge, is unlikely to provide the knowledge required across all the unit operations. The ore type has a meaning to someone but does not necessarily for all unit operations across the value chain.Geometallurgical or orebody knowledge has evolved through the consideration of multiple processes within the value chain, the improved understanding of variability of process performance within ore types and the effect on the complexity of the mineral extraction processes. Furthermore orebody knowledge has been moving from personal based knowledge and understanding to a more process oriented approach where measurement and spatial and process performance modelling is playing a greater role. Advances in mine planning and scheduling allow for both detailed analysis of the block model and the expected extraction processing attributes across various time scales. This capability of analysing and describing the complexity still requires to be communicated to the various unit operations, which may be beyond the traditional classification of an ore type.The limitations of an ore type and potential alternatives to enable the relevant information to be communicated to the relevant groups are outlined through a number of case examples across the value chain.CITATION:Jackson, J and Young, M F, 2016. Ore Type – Everything to Someone but Nothing to Anyone, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 267–274 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By Michael S. Miller

In 1985 and 1986, at the request of the U.S. Forest Service, the U.S. Bureau of Mines studied the 17,000-acre Pyramid Peak planning area in order to evaluate its identified mineral resources. The planning area is located in Riverside County, CA, 15 miles south of Palm Springs. The planning area contains marginally economic resources of marble and mica, subeconomic resources of garnet and occurrences of gold and tungsten. The area is underlain by marble, quartzite, schist, migmatite, intrusive rock, and a wide zone of intensely sheared rock. Quaternary stream, landslide, talus, and colluvial material overlie the older rocks. Ten claims for marble in or overlapping the southwest and southeast parts of the planning area are current (1986). Many other current claims are outside the planning area, adjacent to or within 2 miles of the southwest and southeast corners. Hundreds of millions of tons of inferred, marginally economic marble in and near the planning area may be mined for cement or lime after other developed resources near markets are depleted or if large-scale construction or other markets develop nearby.

Jan 1, 1987

By Richard E. Chism

Jan 1, 1902