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By Markssuel Teixeira Marvila

A Capilaridade, definida como um fenômeno de atração e repulsão, que ocorre no contato de líquidos com um sólido, fazendo com que este líquido se desloque sobre a superfície sólida, é um dos parâmetros primordiais para analisar a durabilidade de argamassas de múltiplo uso. Neste contexto quatro traços de argamassas, dosadas em laboratório e industriais com diferentes níveis de consistência, foram utilizadas para avaliar a correspondência entre as normas brasileira NBR 15259 (ABNT, 2005) e europeia UNI EM 15801 (2010) para cálculo do coeficiente de capilaridade. Os resultados indicam que mesmo seguindo procedimentos bastante divergentes ambas a normas proporcionaram valores de coeficiente de capilaridade para todos os traços estudados. Assim sendo fica comprovada a equivalência técnica das duas normas estudadas para obtenção do coeficiente de capilaridade.

Oct 30, 2017

By Érica Castilhos

Defeitos internos do tipo trinca off-corner são um dos principais problemas relacionados à qualidade em tarugos de aços especiais lingotados continuamente. Este tipo de defeito é bastante crítico, pois além de se apresentar de forma descontínua no tarugo e, consequentemente na barra laminada, não é detectável pelos equipamentos de inspeção em linha usualmente utilizados para garantir a qualidade final do material. Neste trabalho, foram avaliadas amostras de barras laminadas de um aço baixo carbono com e sem a presença do defeito do tipo trinca off-corner a fim de estabelecer um método que permita avaliar a criticidade da trinca. Estes resultados foram relacionados com os principais fatores que influenciam na formação deste defeito, proporcionando alterações de processo com o objetivo de minimizar a sua ocorrência.

Jul 30, 2018

By Rafael Oliveira Sena

A SMS Siemag tem oferecido ao mercado brasileiro novas tecnologias para Lingotamento Contínuo de Placas com objetivo de aumento de desempenho dos equipamentos. A SMS Siemag tem desenvolvido e otimizado o processo de revestimento de placas de cobre do molde que utiliza em conjunto com o processo de eletrodeposição a tecnologia thermal spray que proporciona um produto com alta propriedade de resistência ao desgaste. O revestimento cerâmico, mais conhecido como UniGuardTM, tem obtido resultados excelentes no mercado da América do Norte atingindo valores superiores a 300.000 toneladas. A utilização do revestimento UniGuardTM proporciona um aumento de produtividade e redução dos custos de manutenção do molde bem como redução de aquisição de novas placas de cobre.

Jul 29, 2018

By K F. Tang, J-W Li

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Xiong’ershan district in the southern margin of the North China Craton (NCC) contains more than 20 gold deposits hosted in the late Neoarchean to early Palaeoproterozoic amphibolite facies metamorphic rocks or late Palaeoproterozoic unmetamorphosed volcanic rocks. Gold mineralisation consists mainly of auriferous quartz veins and disseminated ores in hydrothermally altered zones, with additional gold mineralised breccia pipes. Gold orebodies are strictly controlled by secondary- or higher-order brittle/ductile-brittle faults. Isotopic dating reveals two separate episodes of gold mineralisation: the Shanggong and Dianfang deposits formed in the range of 236 ± 1.4 to 202 ± 18 Ma, whereas the Gongyu, Qianhe and Qiyugou deposits formed between 135.0 ± 0.5 Ma and 124.0 ± 1.0 Ma. Stable isotope and noble gas geochemistry studies indicate that the Triassic gold deposits were precipitated from deeply-sourced, low-salinity fluids at 250–350°C, but whether the fluids were mainly derived from metamorphic devolatilisation or magmatic degassing remains unresolved. In contrast, the Early Cretaceous deposits most likely precipitated from a dominantly magmatic fluid, although metamorphic and meteoric components cannot be ruled out. Results from this study, when combined with regional geological and geochemical data, suggest that the Triassic gold mineralisation was generated by the deformation associated with the collision between the North China and Yangtze cratons, forming the Qinling-Dabie orogen. In contrast, the Early Cretaceous gold veining was a result of lithospheric destruction of the NCC, a process initiated by plate subduction from both the south and north since late Palaeozoic but ultimately triggered by the westward subduction of the palaeo-Pacific plate in the late Mesozoic. This study helps to reconcile the long-term debate on the timing, genesis and geodynamic setting of gold mineralisation in the Xiong’ershan and other districts along the southern margin of the NCC.CITATION:Li, J-W and Tang, K F, 2015. Gold deposits in the Xiong’ershan District, Southern North China Craton – products of Triassic deformation and Cretaceous craton destruction, in Proceedings PACRIM 2015 Congress, pp 341–344 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Sudhir Srivastava

India hosts a wide range of globally significant mineral resources, including four fuel minerals; 11 metallic minerals; 22 minor minerals and 52 non-metallic minerals. The country ranks among world?s top five nations for its commodity reserves of coal and iron ore. Interestingly, only small part of country's landmass has been explored that provides opportunity for future substantial mineral discoveries. India plans to double infrastructure investments to US$ 1trillion. Despite the challenges in infrastructure project implementation, mining sector remains a key driver of demand growth for commodities in the years to come with a good prospect to grow in future.

Sep 1, 2012

By Anderson Rosa Pereira

A constante busca pelo aumento contínuo de produção e redução de paradas não programadas em transportadores, tem gerado demanda para equipamentos inteligentes dotados da capacidade de corrigir os constantes problemas de desalinhamento dos TCs. Os métodos hoje utilizados para corrigir este problema são prioritariamente passivos, o que impossibilita uma intervenção mais direta, precisa, automática e efetiva no posicionamento da correia. Esta publicação descreve o funcionamento e os resultados obtidos com a integração do sistema Alinhador Inteligente para Transportador de Correia AITC em um transportador de minério de ferro com vasto histórico de problemas de desalinhamento. Assim, a linha principal deste artigo mostra através de um exemplo prático os benefícios e ganhos mensurados com a aplicação do Alinhador Inteligente para Transportador de Correia.

Aug 16, 2017

By Bruno Miranda de Miranda

O Trabalho proposto demonstra os avanços dos resultados das grandes reformas de usinas de pelotização da empresa Samarco Mineração, unidade industrial de UBU, utilizando de forma sistêmica a metodologia de gerenciamento de projetos IPA (Independent Project Analysis). Através da metodologia obteve-se maior envolvimento e integração dos stakeholders e canais de processo com foco na segurança, saúde e meio ambiente. Outros fatores relevantes foram o aumento da utilização de recursos próprios, modificações de estratégia de contratação e análise crítica das paradas com aprendizado contínuo. Neste trabalho apresentaremos a definição do processo com fundamentação teórica e determinantes de excelência, incluindo os indicadores e resultados obtidos através do método, como indicadores de desenvolvimento abordamos os principais pilares da manutenção, sendo eles: segurança, custo, prazo, acurácia e produção.

Aug 7, 2018

By Estéfano Aparecido Vieira

O presente trabalho busca desenvolver métodos de estudo de remoção de inclusões de aço em escala de laboratório relacionando propriedades como viscosidade e composição química das escórias com a capacidade de remoção de inclusões. Com esse fim, foram desenvolvidas cinco escórias usando como referência a viscosidade da fase líquida assim como o percentual da fase líquida. As escórias foram adicionadas sobre o aço fundido e comparou-se o nível de inclusões antes e depois dos experimentos. As escórias também foram analisadas após os experimentos através da difratometria de raios-x para identificação das fazes formadas. Os resultados apontam que as escórias testadas possuem a capacidade de remover inclusões. Porém escórias com elevado teor de CaO tem maior eficiência na remoção das inclusões.

Oct 30, 2017

By Oswaldo Delfim

Com o aumento da exportação do minério de ferro para os mercados asiáticos e consequentes novos parâmetros nas especificações, principalmente granulométricas para o minério com maior grau de pureza, viabilizaram-se importantes mudanças no processo produtivo, como por exemplo, a classificação do minério em sua umidade natural. Os ganhos adquiridos nesta nova condição de processo vão desde o aumento da recuperação mássica (de 90 a 95 para 100%), menor investimento no Capex e Opex, além dos ganhos na área ambiental como a eliminação da água na rota do processo e das barragens de rejeitos com consequente facilidade na obtenção do licenciamento ambiental. Neste artigo apresentamos os detalhes técnicos das condições dinâmicas ideais da peneira vibratória dedicada a esta nova aplicação.

Aug 16, 2017

By E Amini, N Beaton

Application of ore pre-treatment technologies such as Grade Engineering and in-pit ore treatment require comprehensive analysis to show proven value is being generated by switching away from the current practices. Considering most mining operations last several decades; the pre-treatment technologies must be investigated over life of mine (LOM) to truly show value was generated or lost. Therefore, a value chain flowsheet model has been usually developed to run those analysis/simulations over LOM using a set of defined ore characteristics and the operating equipment capacities. The Integrated Extraction Simulator (IES) has been used for this type of LOM simulations as it has the necessary flexibility to accommodate the whole mining value chain flowsheet in one platform and provide essential computation power to run mass simulations for the given scenarios using the resource block model. This allows to forecast the value chain response over the LOM for all given scenarios in a feasible amount of time. The traditionally developed flowsheets for the analysis/simulations are usually limited to the mineral processing plant and were developed based on a single audit conducted on the plant in a very short time, e.g. several hours. The process plant is being operated with a certain ore at a certain condition during the short audits which would not reveal the true capacity of the operation equipment when ore characteristics changes. Therefore, it would be impossible to define the true capacity of the equipment and identify the constraints along the value chain. In this study, a methodology was developed to identify the constraints along the value chain and implement those in the IES flowsheet using process information. Also, the equipment models were fine-tuned to represent the true capacity of the equipment in the flowsheet using the same data set. The methodology was tested over five process plant in two operations and showed the performance forecast was significantly improved over the traditional methods being used so far. Then those high-fidelity flowsheets were used to evaluate the ore pre-treatment technologies proposed by the relevant resource company experts.

Nov 10, 2020

By Hani Henein

Most metals and alloys processed undergo a solidification processing step. Increasingly, there is a growing number of solidification processing routes that involve rapid solidification of the alloy. These include strip casting, high pressure die casting, 3D printing, and atomization for the production of powders or spray formed parts. By contrast, there are few experimental techniques developed to study the solidification path of alloys during rapid solidification. Amongst these laser melting and solidification, Electromagnetic Levitation (EML) and Impulse Atomization (IA) are the most prominent. Of relevance is the formulation of the solidification path of an alloy and the resultant identification and quantification of metastable phases and their relationship to processing conditions. This typically involves the understanding of the interplay between undercooling and cooling rate for the various phases that form. This presentation will outline some of the methodologies developed to quantify phase fractions and their solidification path as a function of processing conditions using EML and IA.

Jan 1, 2016

By Ralph V. Higgins

The present methods of appraising the long-range performance of oil reservoirs are based upon physical properties of the crude oil and the permeability of the reservoir rock. By means of these methods the performance of a reservoir may be estimated throughout its entire life. Before these methods were used, the future performance was estimated mostly by extrapolating pressure-decline curves -a method that is satisfactory for extrapolating only for a short period into the future. One factor that affects satisfactory long-range prediction of reservoir performance is the extent to which small changes in the physical properties of the oil and differences in the choices of relative permeability influence the calculated oil recovery. Selection of the physical properties of the samples to represent those of the oil and rock for the entire reservoir is difficult. This report is concerned with the error in calculated recoveries that may result from these inherent difficulties.

Jan 1, 1956

By P Valenzuela

Joint mapping is a fundamental input for rock mass characterisation and slope stability analysis. The usual way to do it is using a compass in the field or digitising structures on a screen, with a software package.In this paper a method to identify and map joints automatically along a rock face is presented; it is called the Concentric Shells (CS) algorithm. The method scans a point cloud sequentially, tests if selected points are ‘true pivots’ within an inner shell, and then it searches for points inside a wider sphere (outer shell).The algorithm, developed by the author, was applied in real data. It reproduces the main features obtained from conventional (compass) and digital mapping (software package). Execution times are approximately 45 seconds for two point sets holding of 3.1 million points. Obtaining the same results via digital mapping takes approximately 3–4 working days.Key advantages of this method are: significant time reductions; elimination of mapping bias; and the ability to manage very large data sets (>2 million points) without the need of scanning the cloud on the screen. These advantages make this method an attractive tool for engineers and geologists wanting to increase productivity.CITATION:Valenzuela, P, 2017. Automated joint mapping using the concentric shells algorithm, in Proceedings Tenth International Mining Geology Conference 2017, pp 257–262 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By J. M. Shneerson

At Gipronickel Institute a technological flowsheet of pressure leaching of copper from rich copper concentrates (i.e. containing: Cu -59-75%; Ni -D.5-4.64%; Fe -D.2-J.3%; S -21.8-26.9%) was developed. As a result, the possibility of deep decomposition of copper-containing minerals with extraction of elemental sulphur (up to 90-95%) was established. The obtained sulphur concentrates contain 80-90% of elemental sulphur, which can be separated from sulphide residue through autoclave melting and settling. As a rule, sulphide concentrates remaining after extraction of sulphur contain up to 1-2% of noble metals. The sulphide concentrate can be purified to the level of rich concentrates or pure metals using the well-known methods as in the case of tankhouse slimes. The presented research specifies the parameters of main operations: pressure leaching and sulphur extraction. It was established that 98% of copper could be transferred into solution at temperatures of 108-1 10°C and oxygen partial pressure 0.4-0.6 MPa. Experiments were carried out in autoclaves of various volumes using the products of nickel matte processing.

Jan 1, 2003

By Lionel Ryan

In 1996, the Dominican Republic operation of Falconbridge (Falcondo) developed a 5-year Process Control Plan in conjunction with the corporate Process Control group located in Sudbury, Ontario, Canada. This plan was further refined into an analysis of the areas of the highest potential economic return for the company with the reduction shaft furnace operation being the most promising. Historically, the reduction plant, which comprises 12 shaft furnaces, has been the bottleneck of ferronickel production. Since 1996 there has been a history of control development, and the current status is that all 12 furnaces are using advanced model-based multi- variable predictive control. The combination of advanced process control (APC), improved control system performance and improved process information management has resulted in an increased throughput of 6% per shaft furnace and a reduction in operating costs of 4.5 US cent/lb of Ni. This paper reviews some of the major milestones that have been achieved in this development Keywords: Advanced Process Control; Model Based Predictive Control; Connoisseur, Reduction Shatt Furnace; Nickel Laterite Ore; Ferronickel; MonitorMV

Jan 1, 2004

The Hurghada field is still the major producing field in Egypt. There was almost no activity in the Abu Durba field during 1936 and no new evidence is available. The following table summarizes the information on the Hurghada field for the year 1936. Hurghada Field Age of field to end of 1936, years.................... 23 Producing area for gas and oil, acres................. 1,050 Barbels Total oil production to end of 1936.................. 29,046,572 Total oil production during 1935.................... 1,212,182 Total oil production during 1936.................... 1,218,708 Daily average during November, 1936............... 3,249 MillionB CU. Ft. Total gas production (Aug. 1925 to end of 1936)...... 3,966 Total gas production during 1935................... 278 Total gas production during 1936................... 280 Maximum daily in 1936............................ 0.9 Number of producing wells completed to end of 1936... 94 Number of producing wells completed during 1936. ... 3 Number of wells abandoned during 1936............. 3 Producing wells at end of 1936...................... 768 Average depth of bottom of producing wells, ft....... 1,720 Average depth of top of producing horizon, ft......... 1,598 Character of oil, approx. average during 1936: Gravity at 60' F., 0.900; base mixed. Character of gas, approx. average during 1936: gallons gasoline per 1,000 CU. ft., 6.2. Producing rock (main): Nubian sands, Cretaceous; character, sand rock and sandy shales. 1 The figures given by the author were in tons. A conversion factor of 6.98. based on 0.900 sp. gr., was used to obtain the number of barrels.—Ed. 2 All pumping.

Jan 1, 1937

By Bill Dershowitz

Consider a deep gold orebody with grade of 4 g/t (0.11 oz/st). At the time of this writing, with gold prices at historic highs, it could be a good, but not great, prospect. But if it is a vein deposit, and those veins are 200 g/t (5.8 oz/st), it would be significantly more attractive if there was a way to produce directly from those veins, leaving the rest of the rock in place. [Figure 1 The red around each of the four injector wells shows areas of high pressure, where the lixiviant fluid is pumped into the rock mass, with orange and yellow indicating dissipated pressure. The black lines indicate some of the fracture pathways through which the lixiviant, with absorbed metal, flows toward the central recovery well where low pressure is indicated in blue. Lixiviant is pumped out through the recovery well. Image courtesy of Golder Associates.] There is a way to do this, in situ leach (ISL) or solution mining. It has been a viable commercial technology for more than five decades.

Jan 1, 2011

By A. L. Bailey, B. A. Landry

W. W. ANDERSON and G. E. KELLER*—We want to compliment the authors on this very thorough paper. It gives information which the coal industry has needed for some time. We hope that the additional information which the authors are collecting will he available shortly. The mixing and riffling procedure that was followed for experimental purposes is obviously not practical in routine float-and-sink testing because of the particle size degradation which would result in handling the sample so many times. It is important to obtain our tloat-and-sink fractions with a minimum amount of handling of material. A statement is made in the paper (p. 80) that "the variable most likely to affect the size of sample required to meet a given preassigned accuracy would be the state or degree of mixing of the coal." We agree that this is a large factor, but do not believe it is the most important factor. Our own opinion is that the most important single factor governing the total gross weight of sample that must be collected is the percentage of the weight of material in the smallest fraction that results from the screening and float-and-\ink operations. In other words, size of sample is governed by the total number of fractionations that must he made, and the distribution of material within the fractions. We can imagine a coal with perfect mixing, but with such a small amount of material in some float-and-sink fraction in one of the coarse sizes that a much larger sample would have to be taken than would be the case with very poorly mixed material, but with a large percentage of coarse material more evenly distributed in all float-and-sink fractions. Our own observation of many float-and-sink tests that we have run in our own organization on many types of coal is that the size of sample that must be used on fine size float and sink is governed more by the requirements for weight of material to be used for analysis in the laboratory than by weight of material necessary to obtain accurate float and sink percentage of weight values. In other words, it is our opinion that very small samples can be used for float-and-sink fractionation in the fine sizes, but that accurate analysis of the fractions will depend on a larger weight of sample being pulverized for the laboratory than is necessary to establish the float-and-sink distribution with respect to weight. A. L. BAILEY and B. A. LANDRY (authors' reply)—The authors thank Messrs. Anderson and Keller for their comments based on long experience. It is agreed that the involved mixing and riming technique used may be disadvantageous from the standpoint of degradation. Fortunately, the paper does point out that the extended riming was unrewarding in causing further mixing. Two large unknowns remain, however: (1) how much of the mixing from the presumed highly unmixed state in the bed was achieved toward the random state during blasting, loading, transportation, screening, and further transportation to the point where the gross sample was taken, and (2) how much of the mixing took place during the preparation described preceding riming. As has been pointed out by one of the authors.6 the degree of mixing has a very large effect on the size of sample required and there are still too few experimental data to show at what stage of coal handling most of the mixing occurs. The discussion states that the weight of material in a screened fraction, or in a float-and-sink fraction, is more important than the mixing factor. We do not believe that these factors are comparable in this instance inasmuch as our purpose was to give minimum sampling requirements to achieve a preassigned accuracy in the percentages of float, middlings, or sink, and nothing more. The gross sample had already been screened and no further division by screening was made or contemplated; also, it was not intended that the middlings and sink fractions would necessarily be adequate for percentage ash or other determination. In other words, the sample obtained by the method outlined is not intended for washability studies but only for preparation plant control. Further experimental work has been done, since the paper was prepared, to investigate the effect of increasingly larger top and bottom sizes on the variability of float, etc., of a double-screened coal from Western Pennsylvania. Results will be published and eventually attention is to be given to the preparation of sampling specifications. E. H. M. BADGER*—I should like the authors to explain more fully the fundamental assumptions on which their Eq 4 is based. The equation is of the form s2 = p(l - p) which is the usual expression for the (standard deviation)2 when the chance of finding a particular kind of particle in the sample is proportional to the number fraetion, p. But instead of the number fraction, the authors have used the weight fraction, WF/W. The chance of finding a particular kind of particle in the sample can only be proportional to the weight fraction, if the average ?eig?ts of all kinds of particles, that is, float, midlings, or sink, are the same. Surely a much more justifiable assumption would be that the average volumes of the particles are the same, and, if this is so, Eq 4 would not be true. This may be demonstrated as follows: Let be the weight fraction of float, middlings, or sink, dl the density of this fraction, and d2 the density of the rest of the coal. Then assuming that the average volumes of the pieces in the three classes are the same, the number fraction, p, is given by ? P = d1/l-?/d2 + ?/d1 = ?d2/d1 + ?(d2-d1) The weight fraction, w, in terms of p is given by ? = pd1/(l-p)d2 + pd1 = pd1/d2 + p(d1-d2) _____ [61

Jan 1, 1950

By Robert Stefanko

This report abstracts project work performed for the USBM Grant No. GO-133077 during the period 19 June 1973 to 15 October 1974. Five reports have been separately produced and are as follows: 1. Mine Electrical Systems Evaluation - Cable Splicing, 2. Mine Electrical Systems Evaluation - Explosion-Proofing of Mine Containers, 3. Mine Electrical Systems Evaluation - Transient Analysis, 4. Mine Electrical Systems Evaluation - Mine Power System Performance, and 5. Mine Electrical Systems Evaluation - Model Coal Mine Electrical System Specifications. Abstracts of each comprise the balance of this executive summary, and 50 copies of each volume have been forwarded to the USBM under the terms of the grant agreement.

Jan 1, 1974

By Thornton L. Neathery

A small area in the Alabama Piedmont was studied to determine if metallic enrichment was associated with local magnetic anomalies. Cores from two holes in these magnetic anomalous areas have sulfide (pyrite, pyrrhotite, chalcopyrite) film on slicken-side and fracture surfaces. Two hundred and fifty soil samples were collected from the top of the "B" horizon on 1, 000 foot centers over the general trend of magnetic anomalies. Soil samples were leached with a 1:2. 7 mixture of HF and H2SO4 and the dilute filtrate analyzed for Cu, Pb, Zn, Ni, Co, Cr, Mo, and Cd, using atomic absorption methods. Concentration-value maps were prepared for each element. Small areas of anomalous concentrations were defined for Cu, Pb, Zn, Mo, and Ni. Some of these areas generally coincides with magnetic anomalies. Concentration values (ppm) range from: Cu 165.0 - 0. 5; Pb 265. 0 - 0.0; Zn 1386.0 - 43. 0; Ni 187.0 - 10.0; Co 207.0 - 6. 5; Cr 117.5 - 2.0; Mo 95.0 - 0.0; and Cd 32. 5 - 2.0. Studies of other magnetic anomalies appear warranted.

Jan 1, 1972