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By Javier Ramirez

"Recent R&D pilot plant testing was done to validate a full industrial scale system for recovering residual magnetite from the tails of an iron ore concentration plant. The recovery system is based on an autogenous heavy media separator treating a tailings slurry at 0.45% solids by weight. A 3,100 m3/h capacity concentrator was installed based on the testing findings. Excellent metallurgical results have been observed in two years of continuous operation. This experience is the basis for the proposal of a novel process consisting of the preconcentration of base metals ores; the idea being to obtain a heavy bulk concentrate of the polymetallic minerals and discarding in one step the light gangue mineral components. The bulk concentrate then proceeds to conventional froth flotation. The reduced volumetric flow of the bulk concentrate allows a reduction in the size of the subsequent flotation circuit. A prerequisite for the heavy media separation is a fine size grinding of the ore and a correspondingly high degree of liberation of the mineral species to be recovered. A process scheme is also presented in which the gravity concentrator works in conjunction with a companion tailings thickener for process water recovery. The underflow from this thickener, having paste consistency, can be sent to a tailings dam or mixed with Portland cement for mine backfill. The process water in the system is managed at an estimated recovery in excess of 98%. Additional R&D work using this novel approach is being considered by a large iron ore concentrator for removal of liberated silica from the final concentrate; and for upgrading 3.5 million tons of a marginal hematite reserve owned by the mining company.INTRODUCTIONGravity preconcentration (static and dynamic) of sulphides prior to froth flotation has been and is being practiced at various concentrator plants (Asarco´s Young Mill: heavy media cone; Mount Isa: DSM cyclone; Afton Mines: Denver jigs; Tsumeb Mine: Reichert cone) (Burt, 1984). The idea behind installing preconcentration equipment is to reduce the volume of feed processed on flotation, thus requiring smaller flotation plants although other advantages may be of importance, such as obtaining richer concentrates due to higher grade feed, better process water and energy management, and reduced flotation reagent consumption.The SedconTM solid/liquid separator is a versatile process unit patented in Mexico (MX/u/2007/000305). As a gravity device, it may be classified as an autogenous heavy media dynamic concentrator. Figure 1 depicts the Sedcon (Sedimentador de conos) separator. The four main components are as follows: the feedwell for efficient mixing of the pulp with dilution water and flocculant (and coagulant for water clarification); the inner cones (passive elements for solid/liquid separation); the discharge underflow cone; and the scraper mechanism. The standard discharge cone is a 60° inclined cone for general applications. For paste tailings thickening applications, a deep cone with a 69° inclined cone is used."

Jan 1, 2016

By E. Gervais

"In today's marketplace, heavy competition between materials is the norm. This is particularly true f or the base metals, which are being increasingly challenged by new or improved materials in all traditional applications. Current usage of base metals results from a combination of a metal's intrinsic properties, and technology. The future of the base metal industry rests with innovative, high-quality product development, its ability to take advantage of the results of worldwide, massive material R&D investments, and with the dynamism and effectiveness of its market development programs.The ZA casting alloys program is an illustration of the zinc industry’s efforts to protect and expand its market position in the casting field through state-of -the-art technological developments. The market potential f or these advanced engineering alloys is substantial, and their impact on traditional zinc die casting alloy consumption is particuarly important. The ZA alloys, in offering increased performance through zinc castings produced at low cost and by a wide range of moulding processes, have unlocked a multitude of new end-use applications.Following a review of the development of ZA alloys, of their key properties and of their performance characteristics, the numerous challenges that the alloys present to the zinc industry and to the R&D community are discussed.IntroductionZinc is anodic to steel and has a low, uniform rat e of corrosion; it has a low melting point, can be cast with precision , and is readily finished. In addition to its use in protecting steel and in the production of a wide range of castings, zinc is employed : (1) to produce brass, high-strength aluminum alloys and magnesium die casting alloys, (2) in the wrought state for coinage and in building products, particularly as roofing materials , and (3) as an oxide, in the rubber industry, in ceramics, glass, cosmetics, pharmaceutical products and as the starting materials for many chemicals.Zinc die castings are produced with accuracy at high speed, at low cost, are easily finished and have excel1ent mechnical properties . Car fuel economy, changes in automobile styling, competition from other materials, increased sophistication of design and miniaturization have all led to a dramatic change in the volume of zinc consumed for die-casting applications. This has been particularly notable in the United States. Throughout the 19505 and the I960s, casting was the fastest growing major use of zinc; it was firmly established, accounting for 35% of the total zinc consumption(1), By 1983, the volume of zinc being purchased for casting applications had dropped to less than 20% of all zinc consumed in the United States. In the western world(2), consumption for zinc casting application s is currently at about 15%; being nearly equal to the zinc consumed by the brass industry. Coating applications dominate with a consumption of more than 40% of the total market."

Jan 1, 1987

By M. J. Steffens

ESPLIM is a novel separation technique that combines the advantages of solvent extraction and electrostatic dispersion but its application in the extraction of nickel by the direct solvent extraction route and the effect of high electrostatic field on the stability of organics have not been explored. These were investigated in this study and it was found that the technique allows 97% extraction of the nickel in a single stage compared with 3 stages by the conventional solvent extraction. Also, three months of exposure to 5.0 kV under simulated operational conditions had no adverse effect on the stability of organics.

Jan 1, 2005

By G. M. Ross, I. M. Ross, J. A. Scott

"The otherwise waste heat in many water streams in the mining industry can be used to provide space heating of adjacent infrastructure including laboratories, workshops, and offices. This can be achieved by using heat pump systems, which can work as a replacement or in conjunction with existing space heating. In the example investigated—process cooling streams at an ore smelter—the analysis provided illustrates that annual heating costs can be 19% lower and a simultaneous 62% reduction in CO2 emissions can be achieved.RÉSUMÉ Dans l’industrie minière, la chaleur qui serait normalement perdue des circuits d’eau pourrait servir à chauffer des structures adjacentes incluant les laboratoires, les ateliers et les bureaux. Cela pourrait se faire en utilisant des systèmes de thermopompes, qui pourraient remplacer ou s’ajouter au chauffage existant. Dans l’exemple étudié, des circuits de refroidissement de procédé à une fonderie, l’analyse fournie illustre qu’il est possible de réduire les coûts annuels de chauffage de 19 % et d’obtenir une réduction simultanée de 62 % des émissions de CO2."

Jan 1, 2016

By Robert B. Parsons

"The Department of Finance introduced draft amendments to the resource allowance regulations on July 23, 1992 that effectively nullify the decision in the Gulf Canada Limited case. Prior to the amendments it appeared that only ""directly"" related general and administrative, capital cost allowance and scientific research expenditures had to be deducted from resource profits. Now ancillary expenditures are required to be deducted. Consequently, the ability of taxpayers to claim the resource allowance is curtailed.IntroductionOn October 25, 1990 it was almost certain that taxable mines were going to get a break. The Federal Court-Trial Division had just decided in Gulf Canada Limited's favour to allow it to claim resource related tax benefits larger than what Revenue Canada evidently wished. Revenue Canada appealed first to the Federal Court of Appeal and then to the Supreme Court of Canada. On January 10, 1992 the Federal Court of Appeal agreed with the Federal Court decision and on July 2, 1992the Supreme Court declined to hear any further appeal. A mere three weeks later, on July 23, 1992, the Department of Finance issued draft ""clarifying"" measures to amend the calculation of the resource allowance. These measures effectively nullify the benefits that arose under the decisions of the Federal Court."

Jan 1, 1992

By J. Donnelly, A. V. Deev

Substitution of coal and coke by renewable carbon (charcoal) is a low-risk and low-capital path to 50% or more reduction in net CO2 emissions by the steel industry. However, the high cost of charcoal and its low availability in most countries are barriers for the implementation of this approach. Development of an efficient wood carbonisation technology (slow pyrolysis) capable of producing large-volumes of charcoal from low-cost wood feed (e.g. wood wastes or forest residues) is an essential step towards the use of renewable carbon by the iron and steel industry. This paper provides a summary of the progress made over several years of R&D covering: (1) development and piloting of a new energy efficient slow pyrolysis process for production of charcoal from woody biomass at a competitive cost to the PCI coal, (2) techno-economic evaluation of the process. The main feature of the process is that the material undergoing pyrolysis is heated spontaneously without the supply of heat or air to the reactor. This makes it possible to carbonize large volumes of small-sized wood (e.g. wastes and residues) in a single reactor unit and capture high calorific value pyrolysis by-products

Jan 1, 2015

By W. A. Gow

"In January of 1964, a group known as the Canadian Gold Metallurgists was formed with the backing of the managers of most Canadian gold mining operations. This organization is composed of about thirty mill superintendents of Canadian gold milling operations where the cyanidation process is in use, and one member from the staff of the Mines Branch, Department of Energy, Mines and Re-sources, Ottawa. The aim of this group is to bring together gold mill operators, and research and development people from both industry and government for the purpose of discus-sing common metallurgical problems, and deciding on what operational R and D efforts can be made to help solve these problems. Since the conception of this organization, this approach taken by the gold industry to the study of metallurgical problems has resulted in benefits to all operators, both by assisting them with problems peculiar to their own individual operations and by providing developments of general interest to the industry.This paper describes events leading up to the formation of the Canadian Gold Metallurgists, and how the group has operated since its formation. Examples of progress made toward the group's objectives are given, and possible future programs are discussed."

Jan 1, 1968

By Norman R. Ball

"Many people in the mining and metallurgical industries were brought up to embrace Henry Ford's pronouncement that ""History is bunk"" but it is not generally known that the same Henry Ford created and paid for one of the finest technological museums in the Western World. I am aware that many people feel that industry history is something you ask aging executives to do or that history is a clip-andpaste compendium of pictures re-discovered every 25 years or on the occasion of issuing a press release on plant expansion. Moreover, there are many who fear historians as somewhat deranged individuals interested only in corruption, injustice and sensational labour strife. Good history lies somewhere between the controlled P.R. handout and the hysterical attack. Writing good history is a difficult creative act based on the application of experience, insight, wide knowledge and careful reasoning to available evidence. To date, the Canadian mining and metallurgical industries have achieved a great deal but left too little evidence and it is this lack of evidence which must be corrected before it is too late. It is the purpose of this article to stimulate thoughts with regard to archives, one of the more important vehicles for the preservation of such evidence."

Jan 1, 1999

By J. F. Wright

The cold, or Kississing, Lake area in northwestern Manitoba was the scene of considerable prospecting and mining activity last summer. At the Sherritt-Gordon property, four diamond drills were at work exploring a large deposit of copper and zinc ore, and underground work was in progress on this deposit from two shafts. Some preliminary diamond drilling was completed in five other deposits, and surface exploration work was in progress at a dozen or more additional localities where copper and zinc sulphides were known to be present. Many prospectors visited the area and spent some time in search for new deposits, but apparently few discoveries were made; consequently, last autumn some returned a little disappointed in the area as a prospecting field. Although many visited Cold Lake area last summer in the search for mineral deposits, it should be emphasized that this new prospecting field is a very large one, and that to date only a small proportion of the ground has been examined, except in a very general way. Within the past 18 months, a village of several dozen cabins, and with a population of l00 or more persons, has sprung up on the shore of Cold lake, just west of the Sherritt-Gordon mine. This at present is the business centre of the area, and two banks, a post office - named Kississing by the Postal authorities - a Mining Recorder's office, as well as several restaurants and stores carrying a fairly complete stock of groceries, dry-goods, and general prospecting equipment, are already established.

Jan 1, 1929

By Matthew Janes

Advantages: Clean samples Low sample disturbance Very low spoil Versatile Fast Penetrates all formations Resonant Drill 100 or 150 kW Self tuning to resonance Rotation to 100 rpm Increased depth in dense soil Increased productivity Reduce water use Reduce casing plugging

May 1, 2013

By J. D. Zhu

A numerical model for predicting microporosity formation in aluminum castings has been developed, which describes the redistribution of hydrogen between solid and liquid phases, the transport of hydrogen in liquid by diffusion and Darcy flow in the mushy zone, One of the key features of the model is that it uses a two-stage approach for porosity prediction, In the first stage, the volume fraction of porosity is calculated based on the reduced pressure, whereas, in the second stage, at fractions solid greater than the liquid encapsulation point, the fraction porosity is calculated based on the volume of liquid trapped within the continuous solid network, which is estimated using a correlation based on the Niyama parameter, The porosity model uses thermal data calculated using the commercial finite element package ABAQUSTM. The model has been applied to examine the evolution of porosity in a series of experimental samples cast using unmodified A356 in which the initial hydrogen content was varied from 0,048 to 0.137 [cc/100g], A comparison between the model predictions and the experimental measurements indicates good agreement in terms of the variation in porosity with distance from the chill and the variation resulting from initial hydrogen content.

Jan 1, 2005

By J. J. Benitez

MIBC (methyl-isobuthyl carbinol) was previously shown to enhance significantly sylvite flotation when used at the stage of preparation of amine dispersions. In this paper Atomic Force Microscopy (AFM) is used to study the effect of MIBC on deposition of octadecylamine (ODA) on the surface of mica. The AFM images indicate that amino terminated, and therefore hydrophilic, deposits of ODA are observed on the mica surface in the ODA dispersions free of MIBC. In the presence of MIBC a methyl terminated (hydrophobic) monolayer is obtained on the mica surface. The transition between the monolayer and bilayer phases is due to the presence of MIBC. Experiments carried out in distilled water reproduced the results obtained from the brine. Working in pure water instead of brine simplifies the preparation conditions and the analysis by AFM.

Jan 1, 2006

By Kamran Esmaieli

Open Pit Mining Through Underground Voids: Challenges Main Challenges/Hazards: Unexpected collapse of the pit floor and/or pit walls; The loss of equipment and/or people into underground voids; Loss of explosives from blast holes that broken through into the underground voids. How to address these challenges? An important step that must be integrated into mine planning and design is the accurate detection and delineation of underground voids. (i.e. probe drilling, Geophysical techniques, laser scanning,?); Leaving a pillar of adequate thickness between the working bench and the underground voids; Backfilling the underground voids from surface using vertical or inclined raises; Monitoring the working locations (pit floor and pit slopes) to detect movements.

May 1, 2013

By D. H. Schwarz

The performance of proton exchange membrane (PEM) fuel cells depends on catalyst layer composition and structure. Experimental observations reveal that state-of-the-art catalyst layers consist of microporous agglomerates of carbon-supported catalyst sites bound together by polymer electrolyte. In between the agglomerates are macropores which provide pathways for the transport of gaseous reactants. In this work, three-dimensional, multicomponent and multiphase transport computations are performed using a computational fluid dynamics (CFD) code (FLUENTTM) with a new PEM fuel cell module, which has been further improved by taking into account the detailed composition and structure of the catalyst layers using a multiple thin-film agglomerate model. In this model, it is assumed that thin films of polymer electrolyte and liquid water surround the catalyst sites. The results of CFD computations show that transport limitations associated with the thin film of polymer electrolyte and the presence of liquid water in the catalyst and gas diffusion layers have substantial negative effects on PEM fuel cell performance. Also, the results of computations with variable distributions for a given precious metal loading show that, in general, uniform catalyst loading provides the best fuel cell performance.

Jan 1, 2005

By J. Qi

Based on the commercial steel 42CrMo (4140, SCM440), a new generation of CrMo steel was developed by increasing the content of Mo, adding the alloy element of V and Nb, and decreasing the content of P and S. This new CrMo steel has higher strength of 1500MPa and better delayed failure property. TEM and EDS were used to study the distribution and function of the alloying elements in this steel. A new EELS technique was developed to study the bonding strength of the grain boundary in the steel. The mechanism of strengthening of the new steel has been studied.

Jan 1, 2004

By C. Zangerl, H. Lechner

"Large scale rock slides in deeply incised Alpine valleys are common hazards that can endanger human life, settlement areas and critical infrastructure such as highways, railways and reservoirs (Bonzanigo et al., 2007). In order to perform reliable forecasts of the behaviour of rock slides influenced by large dam reservoirs the geometry, the kinematics, the deformation behaviour and the hydrogeological situation need to be understood profoundly. Based on generic rock slide models the influence of the rock slide geometry on the stability as well as the impact of the buoyancy forces and water load of the reservoir at the toe of the slope are the main focus of this study. Various assumptions of hydraulic conductivity, groundwater conditions of the rock slide and impoundment depth of the reservoir are analysed using limit equilibrium approaches.Generally, deep seated rock slides are characterised by deformation along one or multiple shear zones where most of the measured total slope displacement localizes. Many large rock slides, especially those observed in foliated, mica-rich crystalline rock masses (e.g. paragneisses, mica schists, phyllites), do not fail suddenly or reach high velocities. Instead, many of them move slowly and reach velocities of centimetres per year or even less. Some show episodic accelerations, sometimes reaching alarming levels, but then subside to non-critical levels again. However, there is a potential that deep-seated rock slides fail rapidly, develop into far-reaching run-out rock flows, and cause catastrophic events. Whereas the role of triggers in promoting phases of acceleration is often understood, the same cannot be said regarding the kinematics and dynamic processes by which the rock slide mass decelerates, re-stabilises or accelerates to a catastrophic degree once the trigger impetus has been removed. Thus key questions of the presented work concern the geotechnical, geometrical and hydrogeological conditions under which a slowly moving rock slide is triggered to accelerate to irreversible, maybe dangerous velocities. The development of the sliding zone is generally influenced by pre-existing discontinuities such as brittle fault zones, shear and tensile fractures, foliation and bedding planes. These geological structures determine the geometry of the sliding zone which can either be rotational or translational. During the gravitationally induced failure process the geometry of the rock slide undergoes a change.Several observed post-failure geometries in metamorphic rocks show a concave topography in the middle to upper part of the rock slide and a typical convex or bulge-like topography at the toe of the slope (Zangerl et al., 2012). Whereas the sliding zone of the upper part of such a rock slide mass is rather steep and planar, the inclination of the sliding zone at the toe can be close to zero and act against the driving forces (Alonso et al., 2010). A shear zone that meets alluvial deposits at the foot of the slope encounters a stabilizing impact on the mechanical behaviour. This buttressing effect of alluvial sediments has a remarkable influence on the slope stability."

Jan 1, 2015

By Steve Scott

Green Economy Toyota Prius Hybrid contains about 50 kg of copper. All-electric cars have about 100 kg of copper. From where will all the copper come? Wind turbines have 1 metric ton of copper China is building 221 cities of 1 million people by 2025 (13 cities per year from 2008) = 10 New Yorks. The Greater Toronto Area has 5.6 million people, so a new GTA every 22 weeks!

May 1, 2013

By M. Wittke

"In the course of the extension of the railway network in Israel, currently the two 4.6 km long tubes of the Gilon Tunnels on the line from Akko to Carmiel are being constructed. The tunnels run through the limestones of the Bina- and Yirka-formations, which locally are karstified. The maximum overburden amounts to 160 m.The limestones are mostly horizontally bedded and vertically jointed. Occasionally also inclined joints exist. The tunnels cross various fault zones, which mostly strike at an acute angle to the tunnel axis and are steeply inclined. The karstic cavities which were encountered during tunneling have partially been filled by clay. In the vicinity of the fault zones, the rock has often been strongly jointed and weathered respectively. The two single-track tubes have a cross section with vertical walls and an open invert. The tubes are connected by cross cuts with a spacing of approx. 250 m.During the tender phase, WBI has elaborated the tender design for a joint venture of a Chinese and an Israeli construction company. After the joint venture had been awarded the contract, the preliminary and the detailed design have been elaborated by WBI and the construction works have been guided. On the basis of the geological description, rock mechanical models have been elaborated, followed by stability analyses on the basis of the Finite Element method. The tunnels have been excavated according to the shotcrete method. The support in most areas only consisted of a very thin shotcrete lining and radial bolts in the area of the roof. Depending on the degree of jointing and weathering, locally advancing support by means of spiles has been applied.The internal lining of reinforced concrete has been constructed in parallel to the heading of the tubes. Mucking and delivery of materials was carried out through the cross cuts.The breakthrough was achieved in April 2014 and thus within schedule. The predicted distribution of the excavation and support classes along the tunnel has been in good agreement with reality."

Jan 1, 2015

By A. J. Paul Laprairie

"ADVANCE planning of mining methods, from the first development openings to stope layout and pillar recovery, has long been accepted as a normal method of operating a mine. Recently, mine managers have become increasingly aware that advance planning of cost and accounting controls can also be considered a normal method of operation. The use of such controls is wide-spread in manufacturing industries. In mining, the gold mines of South Africa have pioneered, with marked success, in this field and have been closely associated with most of the research and field work in accounting control. Canadian mine managers are also beginning to realize the advantages of using planned costs. The control procedures which subsequently have been introduced at various mines have come to be known by such names as ""Responsibility Costing"" or Budgetary Control"".Budgetary control, the term used in this paper, is based on the concept of decentralized authority with centralized control. ;The control is achieved by measuring results against yardsticks which are in the form of budgets or standards. Bud-gets are made for the future activities of each possible operation as planned by the department head, and attention is directed to variations from this plan. Furthermore, the control process charges to each operation only those costs which are incurred directly for that operation, and which can be controlled by the person in charge. Thus, budgetary control relates results to the officials responsible for those results. Expenditures are analyzed according to the organizational structure of the mine and the people who run it, and not according to production processes."

Jan 1, 1960

By Knud Sinding

Mining firms are widely criticised for their adverse impacts on the environment. At the same time many firms in the industry devote extensive resources, both financial and managerial, to the reduction or elimination such impacts. Very considerable improvements have been made, although these are sometimes overshadowed by a few high-profile accidents, such as the occasional collapse of a cyanide-containing tailings dam. In parallel, much effort is also directed at projecting a positive environmental image, as witnessed by extensive environmental reporting, both on paper and increasingly through web-platforms. Mining projects today almost invariably involve some form of environmental protection. In industrial countries regulations in this area are extremely stringent, as is enforcement. In less well developed countries, regulation and enforcement may be weaker, but firms are in many cases and for a number of reasons committing themselves to high levels of environmental protection, even if they might get away without doing so. Research in the area of environmental performance of mining firms has so far paid much attention to concepts such as sustainability indicators and the sustainability of individual firms. Given the still raging debates about the appropriate way to determine the degree to which any given firm is sustainable (Welford 1995) as well as the usefulness of what will in the final analysis be a value judgement, anyone on the sidelines of the debate will come back to the fundamental issue, how is knowledge that a particular firm has been judged ?sustainable? going to be made use of. This issue remains unresolved, which may explain the lack of progress in formulating a useful definition of a sustainable firm The question addressed in this paper is not so much about what firms are doing on the ground or in any particular case of environmental protection, but more in the subsequent use of these efforts - and by extension - on the overall direction of corporate environmental strategy. The fundamental problem facing all mining firms is that they cannot easily benefit from unilaterally reducing their environmental impact. The firm can of course avoid liability and keep a variety of stakeholders happy and hence experience lower costs of obtaining the [input] resources they need (in a broad sense, not just minerals), but this represents only part of the opportunities available form pursuing an environmental strategy (Reinhardt 2000). The other part, which may have an enormous potential, involves the concepts of competitor management and product differentiation. The logic of keeping stakeholders happy has been most forcefully argued by Pfeffer and Salanchick (1978) who link the behaviour of firms in all domains to their ability to obtain the resources they need, at a cost that is lower than it would otherwise be (Pfeffer & Salanccik 1978). Several varieties of strategy can be included under this heading, including cost reduction and risk management. The alternative logic is to convince customers that they want to pay more for minerals supplied by mining firm X or directly attributable to mine Y, or by making all mineral users pay more. These two strategies, which may be referred to as product differentiation and competitor management, respectively (Reinhardt 2000) are related to the demand side of mineral supply, whereas cost reduction and risk management are related to the supply side. Mining firms have not pursued the demand side very much, if at all. This is probably due to the extreme difficulty of moving mineral products, bulky and unglamorous as they are, away from their

May 1, 2003