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By Tiago Salzmann Vilela

Durante a produção de arames pelo processo de trefilação diversas falhas superficiais e internas podem ocorrer. Esses defeitos podem ocasionar fratura do arame no processo dos clientes. Um dos defeitos mais clássicos na trefila, denominado “pé de corvo” ou “Chevron”, foi estudado neste trabalho. As principais causas desse defeito estão ligadas à falhas no processo de lubrificação, podendo ser relacionados ao tipo e quantidade de sabão usados durante a trefilação, como também a ocorrência de defeitos no fio máquina empregado e ou, “caminho do arame”. Para esse estudo, diversos defeitos superficiais em fio máquina foram selecionados e então posteriormente trefilados observando a ocorrência do problema nos arames produzidos. Os defeitos superficiais no fio máquina foram coletados de bobinas segregadas no estoque e foram soldados e identificados, a fim de facilitar posterior localização do defeito. A partir do estudo foi possível identificar as causas da ocorrência das falhas por defeito de pé de corvo e propor medidas preventivas que mitigassem o problema.

Jul 30, 2018

By H. J. B. Couto, J. G. S. Puelles, M. L. Torem, R. H. Rojas, A. G. Merma

Understanding the limits of fine particle flotation is fundamental to achieving a significant and selective separation. Conventional flotation processes are not suitable to treat these particles because of their low collision efficiency. This problem can be overcome by decreasing the bubble size or by increasing the apparent particle size. However it is worth noting that the use of small bubbles or micro bubbles also involves some disadvantages such as their low momentum resulting in a slower process comparing with conventional flotation. Electroflotation is an attractive alternative for treating fine particles with small bubbles less than 100 µm, generated by the electrolysis of water. In this sense, this study assesses the effect of current density and pH on bubble size in a binary electroflotation cell. An increase in the bubble generation rate was reported with an increase in current density. In addition, at acid pH values, the size of oxygen bubbles increased and conversely decreased at basic pH values; this may be due to the electrostatic attraction between the oxygen bubbles and the anode resulting in a greater nucleation time. An opposite trend was observed with the hydrogen bubbles. These results are in agreement with their electrokinetic studies, which reported that at acid conditions the bubble surface may be positively charged for both the hydrogen and the oxygen bubbles. Finally the bubble size was slightly affected by the electrolyte concentration, resulting in smaller diameter bubbles at higher concentrations.

Jan 1, 2016

By Akiyoshi Horiuchi, Manabu Kanno, Shigeki Sato, Taro Aichi

"AKITA ZINC Co., Ltd. (Iijima Zinc Refinery), jointly owned by DOWA METALS & MINING Co., Ltd.(DMM), has used the company’s own hematite process for iron control since the beginning of operations in 1971. The hematite process consists of reductive leaching with SO2 gas and iron removal in autoclaves by high temperature hydrolysis. This process enhances not only zinc recovery but also the recovery of gold, silver, copper, lead and rare metals, which is carried out at another DOWA metallurgical plant. All by-products produced in the hematite process are marketed and sold. This paper presents an overview of the hematite process and the recent process improvements made.INTRODUCTION DMM carries out mining and smelting activities for precious metals, PGMs, rare metals and base metals such as copper, lead and zinc. It owns KOSAKA SMELTING & REFINING, producing copper and lead, and the AKITA ZINC Co., Ltd. (AZC) in Akita Prefecture. DOWA is a specialized smelting company which has established a metallurgical complex for copper, lead and zinc, including a recycling business. AZC was established in 1971 at a production capacity of 72,000 t/y zinc; it is jointly owned by DMM and five other non-ferrous metal companies. AZC has increased its capacity continuously and now produces 210,000 t/y of zinc. Figure 1 shows the changes in zinc production and capacity at AZC."

Jan 1, 2016

By R. B. Mears, G. F. Sagar, R. H. Brown

There are well recognized procedures for determining the various tensile, fatigue, and other mechanical properties of the common structural materials. This makes it possible for engineers to design structures of various materials which have adequate initial strength to stand the stresses to which they are subjected in service. There is also considerable general information about protective measures suitable for protecting the usual structural materials from the effects of ordinary environments. However, often insufficient quantitative information is available on the combined effects of stress and corrosion to permit the designer satisfactorily to appraise the structure from the stress-corrosion standpoint. This situation is further complicated by the fact that the stresses causing stress¬corrosion failures are usually not the design stresses but rather the residual forming and assembly stresses which are generally of unknown magnitudes. Thus, tests which will rapidly evaluate the susceptibility of materials to stress-cor¬rosion failures are extremely useful. Of particular value are tests which can be applied to built-up structures as well as to simple specimens, since, as mentioned above, residual stresses often are caused by fabricating procedures and assembly operations. The present paper contains

Jan 1, 1945

By Antti Roine

HSC Chemistry is a widely-used therniochemical tool in the chemical and metallurgical industries and in universities. The main reasons for it's popularity is the easy user interface and the large integrated thermochemical database. This paper summarizes the main properties of the new HSC Chemistry version 3.0, and gives a short review of the new features: Some metallurgical applications with the new features are also presented. HSC Chemistry 3:0 contains seven calculation modules and a thermochemical database with more than 11 ,000 chemical compounds. The new spreadsheet type table editor gives more control to the user, the new graphics routines have fewer limitations and more formatting properties. The capability and speed of calculation routines have also been improved.

Jan 1, 1998

Despite technological improvements and better understanding of the hazards, coal dust explosions stilI occur. Experimental explosions in galleries in various countries extend knowledge with the constant aim of providing safer working conditions. The inadvertent ignition of an accumulation of methane is the traditional initiator of the coal dust explosion.There are specific parameters of coal dust explosibility and explosion propagation, including the important volatile matter in the coal, fineness and dispersibility of the dust and its concentration. Accepting that initiation cannot be absolutely prevented, it is necessary to consider explosion suppression. While both limestone dust and water are the chosen explosion suppressants, in practice water has more limitations to its efficacy when related to the degree of explosion violence. These data give rise to the criteria for explosion suppression, differences in favoured mining geometries, and using the same principles, to differences in suppression treatments.

Jan 1, 1988

By Alfred Guenkel, Kyle Marte, K. Nikolaisen

"The INCO SO2/air process was patented by INCO in 1985 (Borbely, Devuyst, Ettel, Mosoiu & Schitka, 1985). Well over 80 mining operations worldwide are using this process to oxidize cyanides to cyanates in the tailings from gold, silver and copper mining operations. Though it is possible to supply sulphur dioxide (SO2) in either gas or liquid form, the majority of these SO2/air operations use sulphite-based salts as the ‘SO2’ equivalent reducing agent. This is probably due to the lower capital cost, safety concerns with, and availability of liquid SO2. Sodium metabisulphite (SMBS) is commonly employed, and its cost is an order of magnitude higher than that of sulphur. The increased capital expenditures (CAPEX) for a sulphur-burning SO2 gas plant could have a pay-back of less than two years. In addition, a SO2 gas plant offers potential for significant heat recovery from the sulphur burning process. In terms of safety, the SO2 gas plant only requires the storage of relatively benign sulphur and the site inventory of SO2 will be limited to the plant gas inventory. Furthermore, a SO2 gas plant will not trigger the US Clean Air Act Section 112(r) accident prevention regulations, as may be the case for liquid SO2.Most existing mining operations using ‘SO2’ are gold operations, but in recent years there has been an increased interest in larger sulphur dioxide gas plants for hydrometallurgical facilities that employ leaching of cobalt/manganese minerals or precipitation of manganese/iron (e.g. Tenke Fungurume and Boleo).This paper discusses the different processes which require SO2 as a reducing agent and compares the capital and operational costs of a SO2 gas plant to conventional process alternatives using sulphite-based salts or liquid SO2.The heart of the SO2 gas plant is the sulphur furnace. The most economical way to produce SO2 is by combustion of sulphur in air producing up to 19.5 vol% SO2. Examples of large and small sulphur furnaces are discussed in terms of design, operation, and impacts on operational costs.The SO2 gas produced in a sulphur-burning plant has to be contacted with the liquor to be reduced. The choice of gas-liquid contacting device is important, and two contacting devices are discussed: 1) Gas sparging into the bottom of leach tanks (high, nearly constant, back pressure due to liquid head) and 2) absorption columns (low gas-side pressure drop)."

Jan 1, 2014

By ?. ?. Zimin, B. A. Kutlin, X. Baddamsuren

"The ore features of Mongolian fluorspar deposits are shown in the paper. The possibilities of the technological of ore processing on the Bor-Undur combine scheme improvement are analyzed there. Some recommendations are done for scheme development: spare output technologies, the usage large-sized ore separation, flotation by columnar flotation cells, leaching and concentrate agglomeration.New evaluation and usage of mineral sources approach was developed for Mongolian fluoride ores. The conception allows using maximally available mineral resources for getting of metallurgical and acid fluoride concentrates while mining and technological processes: mining (as well as quarrying) -storing, blending-crushing, grinding-combined processing methods-metallurgical using preparation It has been established mining and processing technological schemes should include:• spare blasting technologies providing minimum effect on fluorite crystals which follows ore selective excavation;• large-sized ore separation methods resulted in maximum recovery for these operations in respect to metallurgical fluorite concentrates;• grinding and flotation regimes providing high-quality flotation concentrates getting for their usein chemical industry;• fluorite concentrates agglomeration technologies for providing ability of their use in metallurgical and cement industriesThe results of industrial usage of jugging machines, columnar and pneumomechanical flotation machines for fluospar dressing.The technological approaches implementation in “Bor-Undur” plant maintenance within 1993-2002 years leaded to:• change plant status from just flotation one to gravitational-flotation characterized by technological process stages which are traditional for metallurgical industry and plant capacity increase from 400 to 600 thousand tones of treatment ore as well as concentrate production increase from 120 to 150-170 thousand tones including 120-140 thousand tones of acid grade concentrates with 97% CaF2 ."

Jan 1, 2003

By Ruth F. Brinkley

Principle activities of the Bureau of Mines Explosives Research Laboratory from July 1, 1960 to June 30, 1961 are reviewed briefly in Part 1. Part 1 also includes data obtained in connection with several minor investigations which are not sufficient to warrant separate publications. Part 2 gives brief abstracts of publications that appeared during fiscal year 1961; in general, the research reported in these publications antedates this period.

Jan 1, 1963

By Gian Carlo Ticona

El presente estudio plantea una metodología para realizar el criterio de caracterización geomecánica de macizos rocoso alterados, empleando información geomecánica de la franja metalogenética de Andahuaylas – Yauri, este sector es importante para la industria minera en el Perú, actualmente cuenta con el desarrollo de grandes operaciones mineras y tiene una buena perspectiva para el desarrollo de futuros proyectos mineros. En el cinturón de Andahuaylas – Yauri se tiene yacimientos mineros del tipo pórfido – skarn de Cu, Ag y Au principalmente

Sep 30, 2022

By B. Stewart

Recent ore pass failures have underlined the need for improved designs, standards, structural monitoring methods, and better hang up prevention and removal techniques. Researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) are investigating methods to improve safety during transport of ore in ore passes. Design criteria and hang-up prevention and remediation strategies involve studies of the effects of static and dynamic ore and waste rock loads on chutes, walls, gates, and support structures. Particle flow analysis methods were used to simulate the response of various ore pass designs to a wide range of ore loading conditions. A full-scale mock-up of actual ore pass and chute assemblies was duplicated and tested for load response. Data from a particle flow code and the mock-ups were com-pared. Loads on an active ore pass chute were measured.

Jan 1, 1998

By William A. Johnson, Robert F. Mehl

It is now recognized that several important types of reactions in metallic systems proceed by the formation of nuclei and the growth of these nuclei. The process of freezing is a simple example of this, as Tammann pointed out years ago.1 Tammann held that the rate of freezing is determined by a rate of nucleation, expressed as the number of nuclei formed per unit volume of unfrozen liquid per second, and a rate of growth of these nuclei, expressed as the linear rate of radial growth in units of length per second. For isothermal freezing the conception is simple; for ordinary freezing, extending over a range of temperature, it is not as simple, for the values of the two constants must change with change in temperature. There is ample evidence that the postulated mechanism is correct even though a quantitative derivation of the rate of isothermal or of ordinary freezing in terms of the two constants has been lacking. In recent years other reactions have been found to proceed in a similar fashion. It has been well established, particularly by Bain12-8 that the formation of pearlite from the eutectoid decomposition of the solid solution austenite proceeds in such a way, and Polanyi and Schmid, Tammann and Crone, Karnop and Sachs, and others9-11 have shown that the process of recrystallization proceeds in a similar way. Isothermal reaction rates have been determined for eutectoid decomposition by a number of investigators. Bain's2-8 work on the formation of pearlite from austenite is especially valuable in this respect—the type of isothermal reaction curve obtained, as illustrated in Fig. 13, showed an initial slow rate, accelerating to an intermediate maximum rate which then decelerated to the completion of the reaction; similar curves have been obtained by Wever and his collaborators.12 Other eutectoid decompositions show similar behavior: for example, the decomposition of the beta eutectoid in the copper-aluminum system, studied by Smith

Jan 1, 1939

By William A. Johnson, Robert F. Mehl

It is now recognized that several important types of reactions in metallic systems proceed by the formation of nuclei and the growth of these nuclei. The process of freezing is a simple example of this, as Tammann pointed out years ago.1 Tammann held that the rate of freezing is determined by a rate of nucleation, expressed as the number of nuclei formed per unit volume of unfrozen liquid per second, and a rate of growth of these nuclei, expressed as the linear rate of radial growth in units of length per second. For isothermal freezing the conception is simple; for ordinary freezing, extending over a range of temperature, it is not as simple, for the values of the two constants must change with change in temperature. There is ample evidence that the postulated mechanism is correct even though a quantitative derivation of the rate of isothermal or of ordinary freezing in terms of the two constants has been lacking. In recent years other reactions have been found to proceed in a similar fashion. It has been well established, particularly by Bain12-8 that the formation of pearlite from the eutectoid decomposition of the solid solution austenite proceeds in such a way, and Polanyi and Schmid, Tammann and Crone, Karnop and Sachs, and others9-11 have shown that the process of recrystallization proceeds in a similar way. Isothermal reaction rates have been determined for eutectoid decomposition by a number of investigators. Bain's2-8 work on the formation of pearlite from austenite is especially valuable in this respect—the type of isothermal reaction curve obtained, as illustrated in Fig. 13, showed an initial slow rate, accelerating to an intermediate maximum rate which then decelerated to the completion of the reaction; similar curves have been obtained by Wever and his collaborators.12 Other eutectoid decompositions show similar behavior: for example, the decomposition of the beta eutectoid in the copper-aluminum system, studied by Smith

Jan 1, 1939

By Thorsten Müller

In order to increase the production of Advanced High Strength Steel (AHSS) as well as to fulfill the growing expectations of various industries served, steelmakers must have wide- ranging know-how in terms of plant technology, operation, processes, quality control and, last but not least, know-how for AHSS including certification procedures. MET/Con is highly focused on the production of coated AHSS with tensile strengths higher than 600 MPa. Common heating and cooling technologies are unable to handle high alloyed steel grades – pre-oxidation and rapid cooling technologies have been developed to face these new challenges. MET/CON and Drever International have the knowledge to produce newest steel grades with these technologies.

Jul 30, 2018

By FELIPE SÁNCHEZ, PHILIPP HARTLIEB

Innovation plays a critical role in the mining industry not only as a tool to improve the efficiency of its processes and to reduce costs but also to meet the increasing social and environmental concerns among communities and authorities. Technological progress has also been crucial to allow the exploitation of new deposits in more complex scenarios, such as lower ore grades, extreme weather conditions, deeper deposits, harder rock mass and high-stress environments.  

By M. Stachowiak, M. Nowicki, K. Walas, A. Skoczylas, P. Stefaniak

In this paper the authors present a walking robot dedicated to the inspection of a belt conveyor’s transportation system in an underground mine. The developed robot can independently diagnose all of the key rotating elements of the belt conveyor (pulleys, bearings, drums, gears, engines) based on vibration and acoustic signals as well as typical RGB (red, green, blue) and thermal images. The article presents key diagnostic procedures applied to real industrial data obtained during robot testing.The work was developed as part of the ‘THING–subTerranean Haptic INvestiGator’ project. The authors presented the main assumptions of the research methodology developed for the needs of technical diagnostics of conveyor elements typical of inspection work performed by mining staff. Based on industrial data, the use of algorithms for elements such as rollers, drive stations, and the conveyor belt were shown. The main assumption of the research is to develop a robot adapted to the conditions of a deep mine, capable of carrying out an autonomous inspection of mining infrastructure. The conducted tests and the developed fault detection algorithms were aimed at preparing the robot for underground tests in the operating conditions of the mine.

Sep 1, 2021

By David Ojeda, Efraín Flores, Malena Arrieta

La ocurrencia de deslizamientos de taludes en tajos abiertos es muy frecuente dentro de las operaciones mineras. Por ende, estos eventos no deseados ponen en peligro la integridad de personas, equipos y en algunos casos el riesgo de la viabilidad operacional del negocio minero. Por lo tanto, determinar un sistema de alerta temprana de deslizamiento de rocas y suelos es vital para la gestión y reducción de riesgos dentro de una organización.

Sep 29, 2023

By D. S. Barr

Mineralogical, lithological, and metallurgical studies were conducted on various gold ore deposits currently controlled by Freeport-McMoRan Gold Company. Ore samples were first lithologically and mineralogically categorized, then subjected to chlorination, roasting, and autoclaving pretreatments to determine their effects on gold recovery in a subsequent alkaline cyanide carbon-in-leach extraction. The studies indicate that, while organic carbon and sulfide sulfur are the primary refractory components, their effect on process response must be interpreted with respect to the deposit's geology and mineralogy. This approach has proven to be an effective method for evaluating metallurgical alternatives and fore-casting future mill performance.

Jan 1, 1987

By Kayo Santana Barros

A busca por processos alternativos para o tratamento de efluentes industriais contendo metais tem aumentado devido às limitações geradas pela precipitação química, como a geração de lama e alto consumo de reagentes. Dentre os métodos avaliados, a eletrodiálise se destaca por possuir ampla aplicabilidade, não gerar mais resíduos e pela possibilidade de recuperação do metal. Entretanto, para garantir sua viabilidade, torna-se necessário estudar a estrutura das membranas empregadas a fim de avaliar o comportamento dos íons durante a passagem de um compartimento para outro e definir qual membrana deve ser empregada para cada tipo de separação. Em virtude do exposto, o presente trabalho teve como objetivo caracterizar qualitativamente as membranas trocadoras de cátions HDX 100 e PC-SK por MEV/EDS para avaliar a presença dos elementos químicos em cada uma além de possíveis contaminações, e por FT-IR para determinar suas ligações químicas. De acordo com os resultados obtidos, ambas possuem carbono, oxigênio, enxofre e sódio em suas estruturas confirmando a presença de ácido sulfônico como grupo funcional. As ligações químicas entre os elementos determinados por MEV/EDS presentes nas membranas também foram identificadas por FT-IR. Conclui-se que os métodos empregados no presente trabalho são eficazes para caracterização das membranas avaliadas.

Oct 30, 2017

By Liam Bussey, Graham Speirs

Si bien la automatización de plantas de proceso es quizás la norma actual en la minería, la adopción de esta en la minería subterránea se ha retrasado. En este artículo se compartirán algunas ideas de cómo implementar los sistemas de automatización en la mina subterránea y se explicará cómo la tecnología puede mejorar la operación, de manera que las minas sean más seguras y sus operaciones más competitivas. Se discutirán diversos aspectos tales como los sistemas de comunicación, los sistemas de seguridad, los equipos de producción, los servicios mineros y la gestión de operaciones.

Sep 20, 2019