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By S Morgan, L C Pagdalian, S Serdzeff, C Malaloy-on

It is widely accepted that mineral deposits are decreasing in metal grades. To remain profitable and meet market demand, mining companies are expanding their operations by increasing the tonnage treated. These expansions may include new concentrators with higher nameplate tonnages or upgrading the capacity of existing ‘brownfield’ operations. In many cases, the brownfield upgrade route is preferred as it is less capital intensive; however, brownfield upgrades are never straightforward and present many metallurgical and engineering challenges.For example, to increase feed throughput at a brownfield site, there will be a requirement to modify the mine development plan. This may result in the ore mineralogy varying beyond the current feed fluctuation range. To accommodate these ore variations, a combination of mineralogical analysis and small scale testwork can be used to develop a new process flow sheet to achieve the product recovery/concentrate grade requirements. In general, however, flow sheet development does not usually consider site specific layout constraints and equipment requirements. At sites where future expansions were never considered, taking this silo approach could lead to project delays and compromise the circuit design.Engaging an experienced technology partner ensures the nominated project team is involved throughout all stages and aspects of a given brownfield upgrade – from conceptual flow sheet development, through to detailed engineering, construction and commissioning. The recent Carmen Copper Corporation (Carmen Copper) circuit upgrade has been completed in technology partnership with Outotec. The circuit upgrade was extensive and included new equipment additions to the comminution, flotation and dewatering circuits. Carmen Copper’s intimate knowledge of the ore characteristics, in conjunction with a trusted, knowledgeable technology partner, facilitated a robust circuit design, and fast-tracked the project execution. This paper deals specifically with the flotation circuit upgrade and highlights the benefits to Carmen Copper of this holistic approach.CITATION:Morgan, S, Serdzeff, S, Malaloy-on, C and Pagdalian, L C, 2014. The benefits of technology partnerships during brownfield upgrades, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 471–476 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By H. Saint-Raymond, F. Gruy, P. Gardin, M. Cournil

"The control of inclusion elimination is getting more and more important to obtain clean steel. This paper presents a methodology under development for predicting cluster growth and elimination in ladle - RH system. The first key point is to express the collision efficiency, which is very specific for alumina cluster due to the non-wetting fluid. Second, a description of the two-phase flow in the system is necessary. In our calculations with Fluent CFD package and Lagrangian approach for bubbles, bubble growth is implemented, which improves the predictions. Using global reactor decomposition makes possible the prediction of the time evolution of cluster distribution. Important effect of fractal dimension is demonstrated.IntroductionElaboration of new steel grades requires not only to have a high purity in terms of C, O and N content but also to eliminate particles such as alumina or slag droplets. Flow optimisation making easier inclusion elimination is then a key figure to satisfy cleanliness requirements. Mathematical models of flow and inclusion behaviour are widely used for this purpose (1, 2). But having a predictive tool is still a challenge, because the number of phases is important in steelmaking industry: liquid steel, slag layer, bubbles and inclusions (with a large range of composition and rheology). The paper presents the methodology which is developed at IRSID to predict oxygen content evolution during RH degassing.The main mechanisms which have to be considered are :-inclusion growth by turbulent aggregation of elementary inclusions (keeping in mind that liquid steel is a non-wetting medium for inclusions); the difficulty is to express collision efficiency for alumina particles,-inclusion removal by flotation; the difficulty for alumina clusters stems from the complex morphology of particle; fortunately, the use of fractal concept makes it possible to cope with this problem.The paper describes the general modelling of inclusion removal taking into account the previous mechanisms. Hydrodynamic parameters are obtained by means of Fluent CFD package and a specific coding is developed for cluster growth."

Jan 1, 2001

By Erica McGlynn, Brian Negrea, Lance Jackson

There was no need for the people of Cleveland to ask “Where does the raw sewage go? We want to know!” because it was clear. The raw sewage was being discharged into Lake Erie during heavy rainfall events due to the outdated design of the combined sewer system. In efforts to resolve this ongoing issue for the City of Cleveland, the Northeast Ohio Regional Sewer District developed Project Clean Lake in collaboration with the US EPA. Project Clean Lake is a 25-year, $3 billion program consisting of seven large-diameter CSO storage tunnels to be constructed beneath the city’s existing infrastructure. The first four tunnels have been completed using traditional hard rock TBM excavation methods. The fifth tunnel, the Shoreline Storage Tunnel Project, presents unique challenges and complexities as it will be the first large-diameter EPB TBM to dig under the City of Cleveland. The project itself consists of one tunnel drive 14,100' (2.7 miles) in length, two pipe jacking tunnels, three large slurry wall shafts, two diversion structures, and three regulator reconstructions. Upon completion of the project, 12 permitted CSO locations along Lake Erie will be taken offline, reducing overflow volumes by approximately 350 million gallons per year. This paper will discuss the current status of construction and the chosen means and methods, including the myriad of nuanced differences between hard rock and EPB TBM tunneling methods. Particular attention will be given to the site preparation, setup, and organization; TBM assembly; and TBM launching practices.

Jun 13, 2023

Hard rock TBMs are very often open machine layouts, with just a part roof shield over the front of the machine. The whole system is designed for fast face advance and the economy of the project often depends entirely on the rate of advance. Typically, hard rock conditions will demonstrate stable and good ground for a major part of the tunnel. However, short sections of crushed shear zones with clay and gouge material may cause serious time delays. Spiling rock bolting has been proven to be very efficient under such circumstances, provided the fully grouted rebar bolts can be placed in a controlled and practical manner.Environmental restrictions are becoming more and more a part of tunnel excavation projects. Even hard rock TBM tunnelling may require a strict ground water control, because of consequences on the ground surface from lowering the ground water level. Such consequences may be surface settlement, negative influence on ground water resources or damage to vegetation.Pressure injection ahead of the advancing tunnel face (in this paper named pre-injection), using microfine cement and chemical grouts, is today a proven technology. As examples can be mentioned (Garshol, 1997) about 100 km of pre-injected tunnels below Oslo City and about the same length of subsea tunnelling elsewhere in Norway. Examples from other parts of the world are also available, like below Stockholm, Sweden, the Inland Feeder project and Hollywood Metro both in Southern California.To take advantage of spiling rockbolts and pre-injection, it is an obvious prerequisite to be able to drill the necessary boreholes in the right positions and at the correct angle. In drill and blast excavation this is simple, but in TBM projects it has repeatedly turned out to be difficult. More than once owners have accepted bids containing reassurance from the contractor that the drilling method will be sorted out later. Experience shows that if ælaterÆ means after start of the TBM operation, it is often too late.

Jan 1, 1999

By D. W. Boley

This report contains the results of an analysis of the Logan oilfield, Hocking County, Ohio, and predicts the recovery of oil from the Clinton sand by waterflooding. Core analyses, electrical and radioactivity well-survey logs, reservoir-fluid analysis, and geologic and production data were used for this study. Considered in the evaluation were the reservoir geometry, depth, lithology, continuity of the rock properties, fluid saturations, fluid characteristics, rock wettability, and relative permeability-fluid saturation relationships. The study indicates that a properly engineered waterflood should recover approximately 135 barrels per acre-foot of effective sand. The predicted recovery warrants the initiation of a pilot waterflood in this field.

Jan 1, 1965

By S. R. Stopic

The EU-financed INTREAT Project (Integrated treatment of industrial wastes to¬wards prevention of regional water resources contamination) addresses the environmental pollution associated with solid and liquid wastes/effluents produced by complex sulphide ore mining and metallurgical activities. The results concerning the electrolytic recovery of cop¬per from effluents formed after mixing of streams from Copper Refining, Precious Metals Plant and Electrolyte Regeneration in the Balkan Area will be shown. The waste water is characterized by low pH values and high contents of heavy metals, such as Cu, Ni, Bi, As, Sb. The majority of these waste water flow untreated into the natural water streams and through the network of existing rivers, which end up in the river Danube. The influence of current density and flow rate on the deposition rate, the quality of copper and the process efficiency will be presented. The full continuous process is based on cells with rotating disc cathodes and represents a pre-treatment step before common neutralisation in a cascade line

Jan 1, 2007

By Lóren Kelly de Paula Inácio, Witor Wolf, Renata de Oliveira Melo, Dagoberto Brandão Santos, Graziele Gianini Braga Maria, Nayara Aparecida Lopes Viana

Os aços inoxidáveis duplex combinam as propriedades mecânicas da ferrita com a resistência à corrosão da austenita. Quando submetido a tratamentos térmicos, pode haver precipitação de fases secundárias que prejudicam a resistência mecânica e à corrosão. O objetivo desse trabalho é avaliar a ocorrência de fases secundárias em um aço inoxidável duplex 2205 de grão ultrafino laminado a frio e submetido a temperaturas de recozimento de 600°C a 950°C por diferentes tempos (300-86400 s). Para identificação e quantificação das fases, foram utilizados microscopia eletrônica de varredura, difração de elétrons retroespalhados e difração de raios-x. As propriedades mecânicas foram avaliadas através de ensaios de tração e teste de microdureza Vickers. A presença de fase  e  foi observada junto ao carboneto de cromo, M23C6. A fase  foi confirmada apenas depois do tratamento à 800°C. De modo geral, o aumento do tempo de recozimento leva à uma maior precipitação das fases secundárias. À medida que a precipitação ocorreu, houve aumento da fração volumétrica de austenita e redução da fração de ferrita. Embora a resistência mecânica tenha aumentado, no geral, as propriedades mecânicas, como ductilidade, são prejudicadas pela precipitação.

Oct 5, 2019

By E. Oshilna

The Mitsubishi process has many advantages pertaining to economical and environmental matters. These advantages have led to the installations of the Mitsubishi process in constructing new smelters: The Mitsubishi process utilizes highly oxygen enriched blast air and uses a special lime slag in the C?furnace. These characteristics change the . distribution of Impurities from other processes which use P.S. converters, Recently an Increased amount of secondary materials which contain impurities Is being treated at Naoshima Smelter. In order to cope with an Increment of the Impurities load and maintain the cathode quality, many Improvements have been Implemented. This paper discusses the impurities behavior In the Mitsubishi process and describes the measures taken to treat an Increased ?amount of secondary materials:

Jan 1, 1998

By E. Asselin

Passivation of Fe-Ni-Co alloys during the Caron leach process is thought to result in low cobalt recoveries in ammoniacal ammonium carbonate solutions. A brief review of the available thermochemical data for the (Fe, Ni, Co)-NH3-H2O systems has been undertaken. The stability of the Co(II) and Co(III), Ni(II) and Fe(II) am-mines was examined through the use of speciation and Pourbaix diagrams at 298 and 333 K and at 6 M total ammonia. Increasing the temperature reduces the stability fields of the ammines and generally constrains the thermodynamic window for the leach. The Fe(II) ammines are only thermodynamically stable under reducing conditions. Polarization experiments show that these ammines are unlikely to form if oxygen is present. Fe-Ni-Co alloy passivation may be alleviated by careful management of potential.

Jan 1, 2011

By E. Asselin

Passivation of Fe-Ni-Co alloys during the Caron leach process is thought to result in low cobalt recoveries in ammoniacal ammonium carbonate solutions. A brief review of the available thermochemical data for the (Fe, Ni, Co)-NH3-H2O systems has been undertaken. The stability of the Co(II) and Co(III), Ni(II) and Fe(II) ammines was examined through the use of speciation and Pourbaix diagrams at 298 and 333 K and at 6 M total ammonia. Increasing the temperature reduces the stability fields of the ammines and generally constrains the thermodynamic window for the leach. The Fe(II) ammines are only thermodynamically stable under reducing conditions. Polarization experiments show that these ammines are unlikely to form if oxygen is present. Fe-Ni-Co alloy passivation may be alleviated by careful management of potential.

Nov 1, 2011

By C. L. Lin

The characterization of rare-earth resources in 3D is now possible using high-resolution X-ray microtomography (HRXMT) to describe ore texture and mineral phase composition. In addition, detailed texture analysis, including grain exposure and mineral association, can be described. Preliminary examination of a sample of Mountain Pass ore is reported to describe the spatial distribution of the mineral phases (calcite, barite and bastnaesite), particularly the grain size distribution of bastnaesite. The examination includes analysis of selected particle size classes to determine the appropriate size for liberation of the rare-earth mineral bastnaesite. Good liberation is expected to be achieved if the material is ground to a top size of -150 µm.

By Timothy W. Ellis

"This paper presents the basic theory of operation, physical chemistry and phase equilibria which allow the development of liquid-liquid extraction circuits based on metallic solvents. The incorporation of reduction and reduction/diffusion processes into the process scheme is discussed and a detailed description of several liquid-liquid extraction schemes are developed. A synopsis of experimental results obtained using this method to separate rare earth and other metal based materials will be given.IntroductionConcerns over the effects of waste materials in the environment has been one of the significant social hallmarks of the late 20th century. Essentially every industrialized country has had to incorporate the cost of waste material into the equation of production. Legislative initiatives have led to the passing of very tough laws, by historical standards, which govern the environmental impact of materials processing.Liquid-Liquid extraction is a very common unit operation normally using aqueous and/or organic based solvents. Early work at the Ames Laboratory focused on the use of this technique for the reprocessing of spent fuel from liquid metal breeder reactors by the use of metallic solvents. Recently, we have revisited this area as a means to recycle/reprocess several emerging rare earth based materials, although this method has a much wider range of application. The reinvestigation of this technology is particularly timely as hydrometallurgical based processes are coming under increasing scrutiny in the U.S.A. by the Environmental Protection Agency (EPA). Although technology currently exists to remove contaminants from aqueous based waste streams, often the application of such methods is expensive. With proper design and judicious selection of reagents liquid metal extraction can achieve a high recovery along with a benign waste stream.This process has several possible advantages over other technologies. First is the elimination of aqueous solvents. Therefore, problems associated with disposal or reprocessing of the aqueous carrier are eliminated. Second, with proper system design, very high separation coefficients can be obtained thus limiting the number of stages required. Third, metals are extracted from metals with a metallic product, thereby eliminating the need to re-reduce metal for oxides or other compounds which are the common output for aqueous based extraction procedures."

Jan 1, 1996

By Giovanna Agarelli

Avaliou-se a suscetibilidade à corrosão intergranular de juntas soldadas dos aços inoxidáveis ferríticos AISI 409 e AISI 439 utilizados na fabricação de escapamentos automotivos. A possível sensitização nas zonas termicamente afetadas (ZTA) e os seus efeitos nas propriedades mecânicas das juntas foram avaliados por meio de metalografia e ensaios de tração e corrosão. Observou-se um crescimento dos contornos de grão com a ocorrência de valas na ZTA e a presença de precipitados sensitizados. Também se registrou um limite de resistência e alongamento maiores nas amostras de soldagem manual do que na automática. Concluiu-se que quanto maior o aporte de calor na soldagem, maior o tempo de exposição da ZTA a altas temperaturas, maiores os contornos de grão, menores a resistência mecânica e a ductilidade das juntas. Adicionalmente, a precipitação de carbonetos e nitretos nos contornos de grão comprovou a influência térmica sobre a sensitização.

Oct 30, 2017

By S. L. Ausmus

The work covered in this report is a continuation of an earlier feasibility study by the Federal Bureau of Mines and points out improvements in the skull-melting method for casting reactive metals such as titanium, zirconium, and hafnium. Machined graphite molds with laminated sections can be reused many times. Large tube sections can be produced by spin casting. Graphite powder is the best expendable mold material, but binders for this use must be compounded carefully. The effects of current and furnace atmosphere on the dependent variables of the casting technique are shown. Because of developments in casting technology for titanium which eliminate the basic problems of melting and pouring the metal, opportunities for improvement in the method have increased. The mold material and gate and riser configurations require particular attention. The limits of application of the casting method have yet to be defined. New knowledge in anyone of these areas could result in marked improvements and simplifications in casting methods.

Jan 1, 1960

By S. S. M. Chan

The Bureau of Mines has investigated the structural aspects of shafts and support systems using the finite-element technique. In situ field measurements in deep, vein-type metal mines show that rock stresses are often higher in the horizontal direction than the vertical, and unequal in the horizontal plane. These data and laboratory and field-determined physical properties were used as input to analytical studies. Various design and construction parameters were investigated to deter-mine the effect on shaft stability. Rectangular shafts were studied in detail to determine the effects of applied stress ratio, shaft orientation and dimension, influence of interbedded quartzite and argillite, and rock fracturing. Various support systems were analyzed, including concrete lining, timber, and steel sets. Circular configurations were investigated to evaluate yield zones and liner thickness. Elliptical shafts and time effects were briefly evaluated to illustrate shape and time effects and demonstrate the methodology. It is shown that the magnitude, direction, and ratio of applied stress and rock mass anisotropy are keys to determining shaft stability. A realistic conceptual framework was developed with which to examine the rock and support interaction in deep mine shafts. Structural analysis techniques overcome some of the historical difficulties with shaft de-sign by defining the field data requirements and structural sensitivity of various design and construction parameters.

Jan 1, 1985

By Paulinelli Santos Rocha

A frota de equipamentos retro escavadeiras 345 CAT é responsável pela infraestrutura das minas do complexo Mariana, e este Projeto foi desenvolvido devido a baixa confiabilidade que estes equipamentos estavam apresentando. Foi desenvolvido um Projeto de seis sigma para aumentar a confiabilidade do equipamento que é medido pelo indicador MTBF, calculado pela fórmula: horas trabalhadas/ocorrências corretivas. O trabalho foi desenvolvido através de ferramentas de análise e solução de problemas no período de outubro/2012 a agosto/2013. O MTBF médio da frota era 29,39 horas sendo o benchmark de 47 horas. Foi utilizado o método da lacuna para estabelecimento da meta. Após definido a meta foi utilizada ferramentas de priorização dos focos mais relevantes. Para os focos encontrados foram utilizados análise de variabilidade e cartas de proporção, sendo cada causa classificada e priorizada, definido as ações e implantadas. Foi acompanhado o indicador de MTBF e implantados controles de rotina e padronização com o intuito de alcançar o resultado. Por fim, a meta estabelecida foi alcançada, chegando ao MTBF médio da frota de 42,50 horas.

Aug 8, 2018

By Fábio de Oliveira Braga

Um sistema de blindagem multicamada consiste de uma camada frontal de cerâmica, uma camada intermediária de fibras sintéticas ou de material compósito, e uma camada posterior de um metal dúctil. Recentemente, há o interesse em substituir as fibras sintéticas por fibras naturais, por suas propriedades adequadas, menor custo e peso. O objetivo deste trabalho é avaliar o desempenho de compósitos de matriz poliéster reforçados por fibras naturais de Curauá em blindagens multicamada. Placas com 0, 10, 20 e 30% vol. de fibras integraram a blindagem que sofreu impacto balístico com munição 7.62 mm, e o dano foi avaliado pela indentação característica em plastilina e por uma análise microscópica das superfícies de fratura. Foi mostrado que a blindagem resiste ao impacto balístico, atendendo à norma NIJ-0101.04 para o nível de proteção III. Além disso, as fibras de Curauá são responsáveis por manter a coesão do compósito após o impacto balístico, e o compósito por dissipar parte da energia do projétil por mecanismos como delaminação, trincamento da matriz, fratura e descolamento das fibras.

Aug 16, 2017

The issue of retrenchment is a topic of considerable relevance for the Papua New Guinea (PNG) mining, petroleum and gas industries. The unique environments in which Porgera Joint Venture (PJV) and other similar operations operate are likely to confront these industries with particular dilemmas that will require a range of investments to mitigate the problems associated with retrenchment and employment. This paper discusses retrenchment and employment in the PNG mining industry using the specific case study of PJV. The paper deals with the issue of employment and retrenchment of local workforces in the PNG context, which presents a serious challenge for the resources industry and the achievement of sustainable development objectives. The issue of future retrenchment of the workforce as a result of mine closure is an obvious challenge for both PJV and the Porgeran community at large, who have now come to rely upon both the employment opportunities presented through the mining. This paper examines these challenges and in doing so highlights some progress made by PJV. The paper also discusses downsizing, strategic practices and holistic approaches of retrenchment and employment. In doing so the paper highlights issues that have been overlooked in both academic and applied studies from global and local perspectives in the PNG mining sector. The latter sections articulate the relevance of the information provided by the case study in the wider context of retrenchment. The conclusion promotes a perspective that a great deal more investment will be required by all stakeholders to respond to the challenges of managing retrenchments and mine closure.

Jan 1, 2009

By Elard René Miranda Mecola

"El presente texto busca determinar un esquema extractivo para tratar minerales de ciertas características que permitan recuperar el cobre y el oro presente para el proyecto minero Romerillo ubicado en el distrito de Bella Unión, provincia de Caravelí, departamento de Arequipa. La estrategia de la investigación es tratar de separar extractivamente el cobre del oro, por lo que se efectúan pruebas de flotación para las especies de cobre sin encontrar éxito. Así se utiliza la alternativa de lixiviación ácida de cobre y posterior cianuración del oro contenido en el relave."

Dec 1, 2016

By Vivek Samu, Murthy Guddati

A new method called Effective Dispersion Analysis of Reflections (EDAR) was recently developed to effectively analyze the dispersive waves generated from lateral impact to piles. This paper presents the results of nondestructive length estimation of existing piles through EDAR. EDAR provides a new visualization method for analyzing wave reflections by transforming the response into the frequency domain thus eliminating the need to perform difficult peak picking in the time domain. In addition to being able to analyze dispersive waves, EDAR also incorporates the effects of radiation damping due to the surrounding soil leading to more accurate length estimates. Concrete filled steel tubes of different embedment depths were tested both in laboratory and field conditions. Length estimates obtained were within 10% error margins after careful analysis accounting for the presence of soil effects and effects from pile top reflection.