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By Jean-Sébastien Kroll-Rabotin, Éric Climent, Florent Bourgeois

"Falcon concentrators are enhanced gravity separators designed for concentrating fine and ultrafine slurries. The Falcon UF model is unique in that it is dedicated to beneficiation of ultrafines, one key feature being that it does not make use of any fluidisation water. In a former study, we investigated the physical mechanisms that govern the transport of ultrafine particles (in the range 10 to 80 µm) inside Falcon UF concentrators, and concluded that separation efficiency is governed by differential settling. Initially, we derived and published a predictive model of the partition function under dilute conditions. The present paper proposes an extension of the initial model to concentrated ultrafine suspensions for application to industrial scenarios. The paper discusses how hindered settling has been added into the initial model to account for solid concentration effects. The modified model is tested against experiments carried out with a laboratory scale UF Falcon concentrator from dilute conditions up to 30 vol%. A good agreement between measurements and model predictions is obtained, which confirms that our hypotheses about the physics of separation inside a UF Falcon separator remain valid even at high concentrations.INTRODUCTIONThe Falcon concentrator is a fast spinning bowl that is fed at its centre of rotation. It uses centrifugal force to separate particles that are transported inside a thin liquid film that flows upward along the inclined wall of the bowl (McAlister and Armstrong, 1998). Due to differential settling, dense and coarse particles are concentrated inside the bowl whereas light and fine particles are rejected with the overflow stream. The fast rotation speed of the bowl yields high centrifugal force several hundred times the attraction of Earth. Despite the thinness of the liquid film (between 100 µm and 1 mm with a Falcon L40) where separation takes place, the Falcon concentrator can treat high flowrates (up to 30 L/min). At the bottom of the bowl, an impeller transmits the bowl rotation to the feed, which drains upward by centrifugal force as soon as it hits the base of the spinning bowl (Figure 1)."

Jan 1, 2011

By Kwang-Hyun Jeon

Recently, 3D printing technology in the manufacturing field is in the spotlight. In the construction industry, similar rapid prototyping technology that does not use conventional form can be applied to meet the demand on free formed structure that can provide aesthetic value and functionality. Conventional formwork can increase construction cost and period for various structure with complex shapes while it has numerous advantages such as high strength, convenience, accuracy and good quality of surface roughness. To meet the demand on free formed structure, automated freeform construction systems such as Contour Crafting and Concrete Printing have been developed with active collaboration between university and industry in USA and England. However, details on the system have not been fully released in public, so the possibility of its fusion and spin-off technology cannot be expected. In this paper, cost-effective solution for mechanical and control system for constructing a free curved structure without mold are described. As an appropriate material for the system, fiber reinforced mortar was selected by experiments on compressive strength, setting time and fluidity. After performing G-code simulation, transfer and extrusion experiments with the selected mortar mix were performed and the possibility of the development of automated freeform construction system was demonstrated. Based on this research results, it is required to keep the automated freeform construction system improve and extend it into the new application area in construction industry.

Aug 1, 2013

By C. A. Clark

The Chagres Smelter is located 80 kilometres north of Santiago - Chile, in the middle of an agricultural valley which is also one of the poorest districts in the country. This condition sets the main focus for the smelter's Corporate Social Responsibility (CSR) programmes, which ultimately aim at building self sustainable social and economic capital in accordance with the local capacities. With the help of Anglo American's SEAT (Socio Economic Assessment Toolbox), a corporately developed instrument designed to help the operations understand the needs of the communities and the impacts of those operations, the Chagres Smelter implemented several programmes, such as the CETTA (Experimental and Applied Technology Transfer Centre) programme. This project started in 2003, and consists of creating a centre for the transfer of sustainable techniques and skills for the small agricultural and livestock producers that live in the rural areas near the Chagres Smelter. Its main impacts are: Improved production quality (goat cheese and bee honey) and access to relevant markets, improved training and self-sustainability levels of producers, enhanced socio-economic level of the District's inhabitants by improving their income earning opportunities and technical knowledge, creation and promotion of a local brand as a symbol of quality products from the valley and a positive environmental impact of good breeding and native flora protection practices in the area. Other relevant social programmes are the 'Environmental Strivers', which created a recycling centre in the community; and the 'Beautiful Valley" project, which provides management knowledge and skills to local youngsters and leaders who can contribute to finding solutions for local environmental needs.

Jan 1, 2007

By Amyn S. Dahya, David J. King

"The object of the paper is to discuss the developments in Carbon-In-Pulp (C.I.P.) technology for gold recovery. The CIP process is comprised of four major operations:(a) adsorption of precious metals onto activated carbon;(b) elution (stripping) of precious metals from the loaded carbon;(c) electrowinning of the precious metals from the concentrated eluate;(d) regeneration of the eluted carbon before recycle to the adsorption process.A detailed review of the technological developments in each of the above operations is presented together with a brief theoretical background of the underlying processes. The advantages and disadvantages of the CIP process are discussed in comparison with conventional zinc precipitation. IntroductionThe carbon-in-pulp (CIP) process involves the use of activated carbon for treatment of pulps containing dissolved precious metals, and provide s an alternative to the conventional gold recover y processes using filtration or counter-current decantation in conjunction with the Merrill-Crowe zinc precipitation process. The commercial application o f the CIP process in gold processing technology is a fairly recent development and it is of growing importance around the world.The fact that activated carbon ha s the property of adsorbing precious metals from solution was first published in 1847. In the following years , a great deal of work was carried out to develop an over-all recover y process using carbon, but all attempts were uneconomical because the loaded carbon had to be smelted to recover the gold.It was not until 1950 that Zadra, at the United States Bureau of Mines Research Centre in Reno, Nevada, developed a technique for stripping the loaded carbon using sodium sulphite-sodium hydroxide mixtures and then recovering the gold from the stripping solution by electrolysis. However, this process was not effective for stripping silver and further testwork was carried out on alternative stripping techniques. In 1952, Zadra published a paper describing the use of a hot sodium hydroxide- sodium cyanide stripping technique, which was effective in stripping both gold and silver. This paper included a description and flowsheet for the CIP process which is essentially the same as we know it today. This technique was used in the first major CIP plant, constructed and commissioned in 1973 by Hornestake Gold Mining Company. Since then there have been numerous CIP plants built in the U.S A., South Africa and Australia."

Jan 1, 1983

By C. Boudreault, M. Fortier, S. Fafard

In the forging industry, the increasing trend is to use DC cast billets as forging stock to replace extruded stock. However, there is little technical information available in open literature. In order to gain a better understanding of the behaviour of cast stock during deformation, a study was initiated to evaluate the impact of an homogenisation treatment on the billet prior to cold forging. Axisymmetric upsettings of cylindrical samples machined from DC billets were achieved in order to evaluate and compare flow stresses, crack initiation and propagation. Results show a 30% decrease in flow stress after homogenisation. Observations of the deformed samples show major cracking for the as-cast material. Optical microscopy and SEM observations have related the crack initiation to decohesion around ß -AlFeSi particles and subsequent growth along the constituent path. Homogenisation effectively breaks up and transforms the ß phase, present as platelets in the cast product, into smaller spherodised a-AlFeSi particles. This has the effect of preventing crack growth in the forged product. The homogenisation treatment also resulted in the reduction of Mg and Si in solid solution. The softer matrix generated 29% less die wear when compared to the as-cast structure. Based on the results of this study, it is thus recommended to homogenise cast billets prior to cold forging.

Jan 1, 2006

About MAC ? The national organization of the Canadian mining industry ? Mining, smelting and refining of base and precious metals ? Mining of iron ore, diamonds, uranium, oil sands, coal and industrial minerals ? Many associate members ? www.mining.ca

Aug 1, 2013

By John Blackshaw

NEW sources of supply of tungsten concentrates became necessary when the flow from the Far East was blocked in 1942. In Canada, one source has been noted in the workings of the Hollinger mine at Timmins, Ontario. For many years, a small amount of scheelite had been removed with the gold ore, and an appreciable tonnage of scheelite still remained in the mine. At the request of the Dominion Government, a plant was built to recover this scheelite in the form of a concentrate that could be used by the alloy-steel industry without further preparation. The plant began operating early in March, 1942, and a small tonnage of ore, carrying scheelite and gold values, has been treated daily since then. The possibility of recovering the scheelite had been considered on several previous occasions. Each time the proposal had been given up because the total profits from the enterprise were estimated to be insufficient to repay the capital cost of building the recovery plant. At the time the plant was built, additional information had been gathered about the tonnage and grade of the scheelite ore in the mine, and several thousand tons of ore grading higher than 0. 25 per cent WO3 (tungstic trioxide) were known to be available.

Jan 1, 1943

By R. J. Hundermark, K. van der Merwe, L. R. Nelson

Taphole integrity is critical to all furnaces, but it is especially important in high intensity electric furnaces processing matte and metal of high superheat. Key furnace dimensions are the electrode proximity to the taphole, hearth sump below the taphole and the shape and location of the taphole in the furnace wall (e.g., circular versus rectangular furnace). In addition, electric furnace power density needs to be matched appropriately to any configuration to achieve operational reliability and furnace integrity. The role of furnace dimensioning is generically reviewed across many pyrometallurgical processes to explore potential impact on furnace taphole performance. Some empirical furnace dimensions and power density ratios of industrial furnaces are then compared to explore to what extent they may indeed influence taphole integrity.

Jan 1, 2015

"Le présent article porte sur la diminution des rejets de concentrateurs produits durant l’exploitation et le traitement des minerais métalliques.Le minerai dilué envoyé au traitement a, très souvent, un certain pourcentage du stérile qui affecte directement la rentabilité des opérations souterraines et amplifie l’impact négatif sur l’environnement. Les essais de la séparation du stérile et du minerai effectués en milieu dense sur quelques types de la minéralisation d’or, ont démontré les deux possibilités qu’offre cette technique:• Dans le cas d’un minerai riche, il a été possible de séparer la part importante du toutvenant (minerai dilué contenant le minerai et le stérile) provenant de la dilution, tout en ayant un taux de récupération élevé (supérieur à 96%).• Dans le cas d’un minerai ayant une teneur sub-économique à cause d’une dilution importante, il est possible de produire un concentré ayant une teneur économique à l’entrée de l’usine de traitement, en éliminant une partie du tout-venant.En plus la séparation du stérile peut accroître, en outre, la rentabilité de l’exploitation minière, car le fait d’éliminer la partie de stérile le plus tôt possible diminue certains coûts (transport, traitement et autres). On conclue que la pré-concentration du minerai (séparation du stérile et du minerai) est probablement une seule solution actuellement étudiée qui diminue l’impact environnemental de la mine, sans avoir des conséquences négatives sur la rentabilité de l’exploitation souterraine."

Jan 1, 1997

By T. Holmes

Investigations reveal that the throughput difference between a perfect production day and the average is often on the order of 40%, and that bulk solids handling system deficiencies are the largest (>50%) class of lost opportunities. Root causes for underperformance of elements in material handling systems can often be traced back to the detailed design and even study-stage oversights. To reduce or eliminate bulk solids handling problems in an existing system requires an analysis of troublesome handling equipment – for example, a concentrate transfer chute that experiences plugging, poor flow to the furnace, unacceptable dust generation, and spillage. These problems often lead to significant maintenance costs related to downtime and personnel time. Understanding the cause and cost of flow issues is the first step in troubleshooting the problem. Next, measuring the material’s flow properties is critical to providing design data required to develop a comprehensive scientific solution. In the case of a new installation, the design data is required to properly design the system right first time and prevent flow problems from occurring so that the new equipment works correctly from start-up. This paper highlights the cost of material handling problems and discusses the best approach to evaluate material handling system deficiencies. A case study is given of how Anglo American's operation in Barro Alto Brazil enjoyed a 5-month payback from a bulk solid transfer chute debottleneck project. INTRODUCTION When operating a plant or designing a greenfield or brownfield operation, the intent is to have perfect production days (PPD) each and every day. Money is made by moving material through the plant in a controlled manner to produce the desired product. Mining operations and copper concentration processes are at the most basic level a practice in bulk solids handling (BSH). Unfortunately, many of the project planning steps are overlooked, particularly related to BSH. Investigations reveal that the throughput difference between a PPD and the actual average is often on the order of 40%, and that BSH system deficiencies are the largest (>50%) class of lost opportunities (Wellwood, 2017). Root causes for underperformance of elements in material handling systems can often be traced back to the detailed design and even study-stage oversights. BSH issues are essentially baked into the fabricated plant and left to operations to accept the deficiencies and deal with them for the life of the mine. These deficiencies then become part of the normal operation of the mine and plant.

Jan 1, 2019

By R. M. T. Raja Ismail

Shipping and stevedoring industry is going to witness a massive increase in the amount of containers to be handled while land constraints become more critical. Offshore transfer operations hence offer a preferable solution to deal with the surge in cargos rather than to expand the port outwards. Recently, there has been increasing research interests on offshore crane automation. Suspended cargos in a ship-mounted crane system are caused to swing due to the vibratory motion of the ship induced by ocean waves, which can lead to collision between cargos and deck. Therefore, it is vital for offshore crane systems to satisfy rigorous requirements in terms of safety and efficiency. This paper presents the modelling and control development for offshore boom crane systems. A second-order sliding mode control law is proposed for trajectory tracking and sway suppression control, making use of its capability of actuator chattering alleviation while achieving high tracking performance and preserving strong robustness. The asymptotic stability of the closed-loop system is guaranteed in the Lyapunov sense. Simulation results indicate that the proposed controller can significantly reduce the effect of disturbances coming from gusty waves and other dynamic loadings.

Aug 1, 2013

By F. J. Hrach, K. P. Flynn, P. J. Miranda

"ST Equipment & Technology, LLC (STET) has developed a processing system based on tribo-electrostatic belt separation that provides the mineral processing industry a means to beneficiate fine materials with an entirely dry technology. In contrast to other electrostatic separation processes that are typically limited to particles greater than 75 µm in size, the triboelectric belt separator is ideally suited for separation of very fine (<1 µm) to moderately coarse (300 µm) particles with very high throughput. The high efficiency multi-stage separation through internal charging/recharging and recycle results in far superior separations that can be achieved with a conventional single-stage free-fall tribo-electrostatic separator. The triboelectric belt separator technology has been used to separate a wide range of materials including mixtures of glassy aluminosilicates/carbon, calcite/quartz, talc/magnesite, and barite/quartz. Separation results are presented for selected industrial mineral sources. An economic comparison of using the tribo-electrostatic belt separation versus conventional flotation for barite / quartz separation illustrates the advantages of dry processing for minerals.INTRODUCTIONThe lack of access to fresh water is becoming a major factor affecting the feasibility of mining projects around the world. According to Hubert Fleming, former global director for Hatch Water, “Of all the mining projects in the world that have either been stopped or slowed down over the past year, it has been, in almost 100% of the cases, a result of water, either directly or indirectly” (Blin et al., 2013). Dry mineral processing methods offer a solution to this looming problem."

Jan 1, 2016

By N. Verbaan, Ph. Henry, S. Lamotte

Hydrometal(lurgy) provides an adequate technology to reintroduce otherwise lost metal units into the industrial cycle, thereby saving resources and energy, while keeping the environment cleaner. Three case studies at an integrated hydrometallurgical recycling facility (Hydrométal) in Belgium are discussed. (1) Non-ferrous leach residues are treated by a leach-SX process to recover their minor metals (Ge) contents. The remaining acid waste solution is used by the fertilizer industry nearby. (2) Residual low quality acid and caustic are used in the processing of zinc industry cements to produce copper, nickel, cobalt and zinc concentrates by several consecutive selective leach - precipitation processes. (3) Copper anode slimes are treated and their precious metal contents are recovered. Depending on the composition of the slimes, separate or combined concentrates of copper, bismuth, tellurium/selenium and silver/precious metals can be produced.

Jan 1, 2004

By D. M. Bastidas

The reduction of copper sulfide and copper oxides originated during artificial tarnishing of copper was studied using potentiodynamic potential/current density experiments. Six copper surface treatments were considered: mechanical polishing; indoor exposure for 7 days; chemical etching in 1.6 M nitric acid; chemical etching and heating at 160°C; and chemical etching and dipping in a 9x10-4 M or 0.9 M potassium sulfide (1(25) solution at 70°C. Cuprite (Cu20) and chalcocite (Cu2S) were the main compounds formed. A linear relationship with the square root of the scan rate (v) was obtained by plotting the potentiodynamic potential/current density for the tarnish dissolution processes. A relationship between potential and current density cathodic peaks was not obtained, according to Müller&apos;s model, showing a proportionality factor with the dimensions of a resistance.

Jan 1, 2007

By Mike Broczkowski, Laura Dewhirst, Kieran Large, Angelo R. Fernando, Heather Daigneault, Jim Johnson, Randy Wiens

The radioactive isotope radium 226 is a contaminant of potential concern in effluent waters from metal mining operations in Canada. Acceptable release levels of radium 226 are governed by Metal and Diamond Mining Effluent Regulations. Since radium is invariably present as a companion element in uranium ore, monitoring and controlling of radium 226 is a must for uranium mining operations. Measurement of radium 226 is traditionally carried out through a radiochemical technique involving selective co-precipitation of radium with barium sulphate followed by alpha spectroscopy for quantification. As of 2010, Cameco has also been using an ICP-MS based radium analysis method developed in collaboration with a research team at Trent University, Peterborough, Ontario. This method, which is highly automated and requires significantly less sample handling, with improved turn-around-times, is being used by Cameco site laboratories at the McArthur River and Cigar Lake mines as well as the Port Hope Conversion Facility. This paper compares the benefits and drawbacks of this new method, compared to the traditional alpha counting procedure drawing from almost ten years of field experience.

Jan 1, 2020

By Jorge Amaya

A critical aspect of long-term open-pit mine planning consists in computing a production schedule based upon a block sequencing strategy. Such a schedule should specify when and if blocks should be extracted in such a way as to maximize NPV, while satisfying wall-slope and production capacity constraints. It is well known that this problem can be modeled with integer programming (IP). However, integer programming is not used in practice because the size of typical block models makes such problems intractable to standard IP solvers. In this article we describe a scalable IP-based methodology for solving very large (millions of blocks) instances of this problem. We show that embedding standard IP technologies in a local-search based algorithm we are able to obtain near-optimal solutions to large problems in reasonable time. This methodology has been tested in several mine wide block models.

Oct 1, 2009

By Jorge Amaya

A critical aspect of long-term open-pit mine planning consists in computing a production schedule based upon a block sequencing strategy. Such a schedule should specify when and if blocks should be extracted in such a way as to maximize NPV, while satisfying wall-slope and production capacity constraints. It is well known that this problem can be modeled with integer programming (IP). However, integer programming is not used in practice because the size of typical block models makes such problems intractable to standard IP solvers. In this article we describe a scalable IP-based methodology for solving very large (millions of blocks) instances of this problem. We show that embedding standard IP technologies in a local-search based algorithm we are able to obtain near-optimal solutions to large problems in reasonable time. This methodology has been tested in several mine wide block models.

Oct 1, 2009

By M. A. Hardie

"CASES and mixtures of them are so common and so much a part of everyday existence that they become so taken for granted that their individual characteristics and idiosyncrasies rarely become of curiosity to others than those involved in tl1eir production, processing, treatment, transportation, and for utilization. The use of the most common and universal mixture of gases -air -is begun at birth by ail living creatures and their discontinuation of its use terminates existence. Modern man rides on air in his tires, rides through it for high-speed transportation, and uses it for his comfort in the heating and air conditioning of his domicile. It is neither the aim nor the in-tent, in the next few moments, to provide a panacea for even a portion of the problems inherent in the gas industry nor to delve deeply into any particular facet of its diversities. The purpose is primarily to touch upon some of the peculiarities and generally to consider approaches to employ in the pursuit of solutions."

Jan 1, 1959

By Mel Torrie

1 Want access to low level vehicle data so 3rd party apps can be applied as desired 2 Hardware Agnostic (COTS plug and play) 3 Common/Open protocols that facilitate integration and the coexistence of a variety of applications on a variety of equipment 4 Minimum computer hardware footprint 5 Technology Independence (including comm. backbone)

May 1, 2013

By J. F. Henderson

THE National Advisory Committee on Research in the Geological Sciences was established seven years ago - in 1949. In 1952, shortly after the Committee had really begun to function and had issued its first report, a paper ( l) was presented describing the objectives and organization of the Committee and the progress to that time. Another four years have gone by and the Committee feels a further progress report may be of interest. HISTORY Ten years ago, in 1946, the Geology Division of the Institute set up a Committee on Geological Research. This Committee, under the Chairmanship of Dr. J. E. Hawley, recommended that "a National Advisory Committ.ee on Research in the Geological Sciences be formed" (2). With the backing of the President and Council of the C.I.M. this recommendation went forward to the then Minister .of Mines and Resources and, with his approval, to the Committee on Scientific and Industrial Research of the Privy ?Council. As a result, the National Advisory Committee was set up in 1949.

Jan 1, 1956