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By G. C. Weatherly, L Beitelman, M Gray, M. W. Bates, R Hadden

"A program of evaluation of in-mould electromagnetic stirring on the product of a straight-mould, billet continuous casting machine has been carried out. The effects on macrostructure, surface and internal quality, chemistry segregation and mechanical properties on carbon, low-alloy and resulphurized, free-machining steel billets and rolled bars are discussed. Operational aspects as a result of in-mould stirring are highlightedIntroductionA development program on electromagnetic stirring (EMS) in the mould of a continuous caster was started by Ferrco Engineering Limited in 1979, with the first experimental device being developed and installed at Lake Ontario Steel Company. As a result of these initial trials, new designs of in-mould EMS systems have been developed and are currently being used in continuous casters in North America and Europe. The rapid progress which has been made is in large measure due to the fruitful cooperation which has existed between the various parties, including Ferrco, the EMS equipment manufacturer, several operating plants and the University of Toronto.A brief review of some of the basic ' principles of electromagnetic stirring action on solidifying metal, and the landmarks of this process development, will explain the philosophy of this cooperation.From casting practice, it is well known that an equiaxed dendritic structure provides better' material properties than a columnar dendritic structure. Homogeneity of the equiaxed structure leads to better control of material properties, such as strength and ductility. Therefore, many efforts are being made to obtain this structure in continuous casting.The extent of the equiaxed zone is determined to a large degree by convective flow in the liquid. Fluid flow can fragment dendrites in the columnar zone, which then act as nuclei for grains in the equiaxed zone farther down the sump. This process is referred to as dendrite or grain multiplication."

Jan 1, 1982

By Francis Dakubo, Courtney Young, Avimanyu Das

"Hydrometallurgy of copper ores typically involve acid leaching followed by solvent extraction and electrowinning (SX/EW). EW is the final purification stage in which a voltage is applied across two electrodes causing the copper ions to reduce and deposit on the cathode. Applied voltages are near 2 volts with current densities around 300 amps/m2. In this study, research was undertaken to decrease the energy consumed in the EW process. To do this, various cell designs were constructed and tested in which a membrane was used to separate the cathode and anode compartments with concentrated solution from SX serving as catholyte and raffinate from SX serving as anolyte. Therefore, copper in the concentrated solution would be deposited on the cathode while ferrous in the raffinate would be oxidized to ferric at the anode. Because it is assumed that ferric acid leaching is used, resulting ferric would be recycled to the leaching process. A positive side effect of the envisioned process would be the elimination of oxygen evolution at the anode and thus the prevention of acid-misting. After a cell design was selected, it was used to test a number of variables: flowrate, concentration, temperature, ion-exchange membrane, and applied voltage. Following experiments in which variable ranges were determined, statistical modeling was conducted using STATEASE software. Optimal results indicate the voltage can be decreased to 1.5-1.7 volts with current densities of 300-400 amps/m2. Significant reduction in the energy consumption was accomplished by reducing the applied voltage. Furthermore, current efficiencies and copper production rates was increased by application of the membrane.INTRODUCTIONLeaching of copper ores is achieved using mostly sulfuric acid. The copper pregnant solution is contacted with an organic solvent or resin adsorbent which picks up copper ions as in Equation 1:"

Jan 1, 2016

By S. Zador

"IntroductionIn the past decade, metallurgical and mining companies have shown an increased interest in the licensing of technology. When licensing technology, it is usually to the benefit of the parties, to have at least some of the technology to be licensed protected by a patent.This paper is intended to bridge the gap between the engineer in the field of mining, metallurgy and mineral processing who is interested in exploiting an invention commercially, and the patent agent or intellectual property lawyer whom he/she might retain to prepare a patent application and then prosecute the application to obtain a granted patent. It is also intended to encourage the inventor or a small business concern to consider the value of patents in the sale and licensing of technology. The lawyer may subsequently advise and assist the inventor in licensing his/her invention.A brief outline of some of the basic features of the patent system follows. The nature of the information, which the patent professional requires from the inventor to enable him/her to draft a patent application, will also be considered in general terms. Furthermore, various types of licenses which may be drawn up between a licensor of specific technical information and a licensee, will be listed and briefly discussed. No attempt, however, will be made to give a comprehensive and detailed account of the above aspects; the interested reader should consult legal publication and reference books, and patent professionals for further specific information.A granted patent is a document which describes an invention and how to practise it. The claims of the granted patent, figuratively speaking, fence off the intellectual property the inventor regards as his invention. The Commissioner of Patents, representing the Government, grants to the inventor or his assignee the exclusive right of making, constructing and using the invention, and selling it to others to be used, for a limited period of time, in exchange for disclosing the invention to the public. Thus, a patent prevents others from practising the claimed invention but it does not, necessarily, bestow the right to the patentee to practise his own invention. The term of a patent now in Canada and in most of the developed countries of the world, is 20 years from the date of filing the patent application. In the United States the patent term is still 17 years from the date of issuance of the patent. In Canada, the term was changed to 20 years in the new Canadian Patent Act which came into force on October 2, 1989. Any patent application filed prior to that date or granted before it, retains a 17 year life, commencing at the time of grant."

Jan 1, 1991

By Ferri P. Hassani, Riadh Bouzaïene

"Selected methods of pressure loss predictions in horizontal slurry flow in pipelines are presented. For a given combination of flow velocity, solids concentration and particle size, the slurry and its flow conditions are described, and an appropriate method of pressure loss prediction is outlined. The wide range of conditions treated in this paper may be found in practice in areas varying from the hydraulic transport of low concentration slurries to dense-phase conveying of paste backfill in underground mines.IntroductionThe hydraulic conveying of solid particles in pipelines is a major component of the mining and mineral processing industry. Whether the objective is to transport ore to the processing plant or to make use of mill tailing as backfill material; the need for well designed, economical hydraulic conveying systems is recognized.The contribution of this paper is part of an on-going research program at McGill University involved in optimizing and developing techniques for total mine waste disposal. One of the main concerns in the conveying of solid-liquid mixtures is the prior knowledge of the pumping power input required. This energy requirement is directly proportional to the pressure losses incurred in the pipeline system. Understanding the sources of such pressure losses and predicting their magnitudes should enable the system designer to make informed decisions regarding the optimum mode of hydraulic transportation commensurate with the over-all requirements of the operation.This paper is an attempt to classify pressure loss prediction methods encountered in the literature for solid-liquid mixtures. In spite of the large number of publications spanning thirty years of research in the field of slurry transportation, it is sometimes difficult to correctly identify the appropriate methods applicable to a given situation. This is partly due to the inherent complexity of the mechanics of slurry flow and the ensuing uncertainty about the nature of the flow regime under investigation.Our approach is to use three fundamental parameters, namely: flow velocity, solids concentration and particle size (for solid particles with a given density) to characterize the slurry and the flow conditions, and to match them with an adequate pressure loss prediction method. For each combination of flow velocity, solids concentration and particle size, a description of the most likely prevalent flow conditions and some known methods of dealing with them will be presented. Qualitative definitions of ""high"" and ""low"" magnitudes of the aforementioned parameters will be given as a general guide to the classification scheme presented in this paper."

Jan 1, 1992

By M. Mirnezami, J. A. Finch

The McGill component of the consortium contributed detailed examination of the electrokinetic properties of the constituent minerals, primarily pentlandite and serpentine. Mineral specimens were derived from an ore sample; mineralogical examination showed the serpentine was predominantly clinochrysotile, a fibrous mineral responsible for much of the flotation separation problem. The study included design of a novel sedimentation potential measuring device to classify the surface charge of the ore and electrophoresis measurements on single and mixed minerals which progressively approached flotation conditions. The sedimentation potential measurements provided a general association between surface charge and the visual state of aggregation as a function of pH. The electrophoresis experiments started with single minerals in a background of indifferent electrolyte and progressed to mixed minerals in a background of supernatant derived from an ore sample. The single mineral tests supported the suspected electrostatic interaction, i.e., hetero-coagulation, at flotation pH 9-10. The mixed mineral tests demonstrated this interaction and also revealed hetero-coagulation with Mg(OH)2 precipitates, derived from the supernatant. This interpretation was confirmed by optical and electron beam imaging. A series of agents, CMC, polyphosphate, soda ash, EDTA, were examined to disperse the system. To accommodate the small mass of single mineral available a novel turbidity measurement using a UV/Vis spectrophotometer was introduced. Selected conditions were used in contact angle and small-scale flotation tests.

Jan 1, 2011

"Process specifications for classification system design f or closed circuit grinding are identified. A computer-assisted, mass balance procedure for estimation of material size distributions and required hydrocyclone separation performance is presented.GeneralClassification equipment application involves a large number of variables, but can be greatly simplified by consideration of the following two major steps:(A) Process analysis, in which the so lids and liquid material balances and solids size distributions in the three classifier streams are determined in order to establish the required classifier separation performance.(B) Equipment selection, in which the cyclone dimensions and feed conditions are selected to yield the de sired separation, and the number of units then determined by their capacity rating."

Jan 1, 1984

By André Bérubé

"IntroductionSince the disappearance of Les Forges du Saint-Maurice at the end of the last century, many historians have taken an interest in the lengthy past of this enterprise. They considered the political, socio-economic, administrative and anecdotal aspects of the industry, but barely dealt with the elements of technology. The purpose of this article is to try to fill this gapru.Les Forges du Saint-Maurice was an integrated industrial concern, specializing in the production of semi-finished wrought iron and finished cast iron, that operated almost without interruption between 1734 and 1883. Les Forges first came into being in 1729, when Montreal merchant Francois Poulin de Francheville submitted to the king of France a request for the right to exploit the bog iron ore deposits on his seigneury of Saint-Maurice. This request, agreed to in 1730, was one of a long series of attempts, previously unsuccessful, to establish a local iron industry in the colony. Several such proposals were held up by a lack of capital from promoters or a too rigid application of the mercantilist policy by the metropolis. In 1730, however, the French minister Maurepas favoured a more liberal policy which would encourage private enterprise. The benefits of an iron industry to the naval construction industry was a factor that caught the attention of administrators. The choice of the site for Les Forges was based on the following factors:• the abundance of surface deposits of bog iron ore in the Saint-Maurice region;• the presence of a vast supply of hardwood and conifers needed in large quantities by this industry;• the proximity of sandstone and limestone deposits, indispensable materials for the construction and operation of the blast furnace;• the presence of a water stream, with sufficient flow to provide the hydraulic power needed for the operation of the machinery."

Jan 1, 1983

By K. C. Corin, M. S. Manono, J. G. Wiese

Depressants play a crucial role in the flotation of PGM bearing ores as they prevent naturally floatable gangue (NFG) from reporting to the concentrate. This action is regarded as critically important because less dilution of the concentrate means lower costs for downstream processes. However, abnormal water conditions (such as high concentrations of ions) in the flotation system can modify the selectivity of these depressants. It is well known that the existence of selected electrolytes in water can alter the behaviour of some polysaccharide depressants by enhancing their adsorption onto gangue minerals and thereby prevent naturally floatable gangue from moving into the froth phase. Concurrently these same electrolytes may enhance frothability, owing to their stabilising effect on the bubbles within the system. Plant water at various ionic strengths was investigated against depressant type and dosage in order to understand electrolyte-depressant interactive effects during the flotation of a Merensky ore, using entrainment, rate of NFG recovery, and total gangue recovery as proxies. The study showed that the rate of NFG recovery per unit mass of water decreased with increasing ionic strength at all dosages, however the total amount of gangue reporting to the concentrate increased with increasing ionic strength at all depressant dosages. Thus, this paper attempts to consider the effects of both ionic strength and depressant dosage as individual factors within flotation. It further looks to investigate whether any interactive effects exists between these two factors when considered simultaneously.

Jan 1, 2016

By C. E. Baltzer, W. H. Harper

"This study has been developed to illustrate the trend and pattern of distribution applying to the quantities and costs of the fossil fuels used, and the related amounts of electricity generated, in the thermal segment of the Canadian electric utility industry.Traditionally, Canada's requirements for electric energy have been preponderantly met by hydraulic power. The need for augmented supplies of thermally generated power has mainly developed since the close of World War Il-in an era that has seen drastic decline in the production of indigenous coal and buoyant expansion in the supply of oil and natural gas. Although coal currently is faced with serious competition from the fluid fuels, the utility industry in particular promises an advancing market for coal, because of its abundant resource, at prices less likely to show sharp increase. For Canada as a whole, this trend has been progressive since 1959, and, unbelievable as it may now seem, the extent of the advance by 1975, particularly in Ontario and the Prairie Provinces, may well be as much, or even more, than the present rate of consumption for all purposes.The text and the tables and charts are arranged to focus attention on: the growth of thermal genera ting capability; the historical trend in consumption of fuel and the related production of electricity; patterns of distribution by types of fuel and thermal capacity; the relationship of steam to other sources of thermal capacity; and the quantities, costs and related percentages of electricity generated by types and kinds of fuel used, both regionally and provincially."

Jan 1, 1966

By Robert B. Parsons

"This month, Tax Notes focuses on two features which can potentially ""dress up"" a new issue of common shares to make the shares more attractive to investors. Attaching warrants to a share issue is a relatively common practice, and recent years have seen an imaginative variety of different kinds of warrants, some of which can be subject to somewhat different tax treatment . A less common financing strategy which certainly deserves some consideration involves the possibility of utilizing ""Share Purchase Tax Credits "" in conjunction with a new share issue.IntroductionPrevious subjects covered in Tax Notes have dealt with flow-through shares and other tax angles which can make equity issues more appealing to potential investor s. Two other techniques which can add zest to a new stock issue involve the utilization of warrants and ""share purchase tax credits"" (or SPTCs). This article takes a brief look at the better known subject of warrants and the lesser known matter of SPTCs.Of course, this paper presents only a relatively general summary of the income tax implications of warrants and SPTCs, and is not intended to be a definitive commentary on all of the detailed and complex tax issues that might be relevant in the circumstances."

Jan 1, 1985

By S. M. Fatemi-Varzaneh

The AZ31 magnesium alloy is considered as a promising alloy in various applications and industries. Furthermore, to design a proper hot working process (rolling, forging and extrusion), the assessment of hot working behaviour of the alloy is necessitated. Accordingly, the hot deformation behaviour of AZ31 alloy was studied through hot compression testing method. The latter was carried out in a wide range of temperature (523 K to 783 K) and strain rates. The obtained true stress-true strain curves and final microstructures were examined and a partial melting was realized at 740 K. It was concluded that the presence of liquid did change the deformation mechanisms thereby affecting the flow behaviour.

Jan 1, 2005

By A. M. Reyes

Flow field hydrodynamics of serpentine flow channels was investigated numerically using computational fluid dynamics (CFD). The velocity profile simulated by the CFD model was evaluated with respect to experimental results from the literature. Rectangular and tapered flow channels were compared with respect to mixing and water management capabilities, and pressure drop. The CFD model was further developed to account for electrochemical reaction on the cathode side to determine which channel configuration was most effective in reactant conversion. The velocity profile differences between the channels were found to impact reactant conversion, as the rectangular channel had the highest conversion. With respect to water management, although the tapered channel was found to have a higher overall pressure drop, the rectangular channel was found to have higher shear and pressure forces acting on simulated liquid water droplets in the channel.

Jan 1, 2005

By G. E. Norman, J. F. Jackson, A. L. Mckague

"The treatment of nickel-copper concentrate in the new smelter at Falconbridge Nickel Mines Limited, Falconbridge, Ontario, is described. The concentrate in a slurry form is partially roasted in a fluid-bed roaster and the calcine is smelted in an electric furnace. The roaster gases are treated in an acid plant. IntroductionSmelting began at Falconbridge in 1930 with the first blast furnace treating high-grade ore containing 2-3% nickel. In 1933, the Falconbridge concentrator was built and started producing a bulk sulphide concentrate containing 4% nickel. A sinter plant was built to agglomerate and partially roast this concentrate. The sinter was smelted in blast furnaces along with high. grade magnetic ore. Matte from the furnaces was treated in Pierce-Smith converters to produce shipping matte which was refined at the company's plant in Norway."

Jan 1, 1980

By W. L. Brown

"The properties of Base Metal Mining Corporation are in Yoho Park about 2 1/2 miles northeast of Field; British Columbia; on the main line of the Canadian Pacific railway. There are actually two mines; the Monarch on mount Stephen and the Kicking Horse on mount Field; separated by the steep valley of Kicking Horse river. The outcrops of the orebodies range from 4; 900 feet to 5; 300 feet above sea-level. The concentrator is situated below the Monarch mine and is connected to the main portal by an aerial tramway. The ore from the Kicking Horse mine is conveyed by aerial tramway to a storage bin on the main highway and is then trucked to the concentrator.During the construction of the Canadian Pacific railway through Kicking Horse valley, galena float was found at the base of mount Stephen. The East Monarch outcrop was staked in 1894. The outcrop of the West Monarch ore body on the cliff face of mount Stephen was not discovered until 1916. The Kicking Horse orebodies on mount Field were discovered a few years later. In 1912, a 75-ton concentrator was erected, which operated at intervals until 1924. During this period approximately 42,000 tons were mined and milled, largely from the East Monarch orebody. In 1928, the Base Metal Mining Corporation, Limited, was formed to take over the Monarch and Kicking Horse mines. A 300-ton differential flotation concentrator was erected and production started in the autumn of 1929. In a very short time, however, the low price of metals forced the mill to shut down until August 1933. From 1929 to 1935, when the mill again ceased operation, a total of 256,500 dry tons of ore, averaging 1.59 oz. silver per ton, 9.7 per cent lead, and 12.6 per cent zinc, was mined and milled, largely from the West Monarch orebody. After a period of further underground development, the concentrator reopened in 1940 and is still in operation. From 1940 to the end of 1944, 354,363 tons of ore was milled, averaging 5.32 per cent lead and 10.47 per cent zinc."

Jan 1, 1954

By A. Lopez-Valdivieso

Particle size enlargement processes play an important role in solid/liquid separation, and in beneficiation unit operations. In the latter, not only the size of the formed aggregates but also their surface properties are very important. Oil agglomeration has a special place among such processes: it is a selective process in which hydrophobic particles are agglomerated into hydrophobic agglomerates which can be recovered by flotation. This explains the broad applications of oil-assisted beneficiation processes not only in the beneficiation of fine coal, but also in agglomerate flotation of many different types of ores, and in coal/gold agglomeration.

Jan 1, 2004

By B. Hewitt

Murrin Murrin Operations has not had a successful beginning. Numerous reliability and operability issues many of which are the result of design decisions have been addressed through mechanical and operational changes and the CCD circuit is no exception. The decision to install, the installation and the results of the CCD1 rake-lift mechanism and feedw ell dilution system are discussed in this paper. The installation was justified on improved operational robustness and an increase in the in the underflow density of 1% (per cent w/w). At approximately the same time process modifications in the solution neutralisation circuit were implemented and these changes altered the rheology of the slurry reporting to CCD1. Since the modifications to CCD1 and the solution neutralisation circuit, the CCD circuit has averaged a 2% improvement in the circuit underflow density. The CCD1 modification was completed on time and mechanically has performed well. From a risk point of view, the central rake-lift and Turbodil® dilution system add a degree of freedom and robustness to CCD1 operation that has extended the range of operational confidence. In this respect, the modification has been a success and is complementary to solution neutralisation improvements.

Jan 1, 2004

By J. E. Carter, D. P. Wall

"This paper details the highlights of the open-pit and underground operations of Mclntyre Mines Limited in the Smoky River area of Alberta. Mining methods, operating equipment and manpower are outlined, followed by a discussion of reclamation and environmental control.IntroductionMcintyre Porcupine Mines Limited was incorporated in 1911 and for many decades was known primarily as a gold producer in the Porcupine district of northeastern Ontario. The company, however , has held coal leases in the Smoky River area, near Grande Cache, Alberta, since 1921. Preliminary studies were carried out in the region from 1959 to 1963. In 1964, Mitsubishi, a leading Japanese trading company, (on behalf of Mcintyre), investigated the area as a possible source of coal for the Japanese steel industry. The initial report concluded that Smoky River coal was of high quality, comparable with some of the best metallurgical coals in the world."

Jan 1, 1981

Strengthening a mine with the Power of their Employees: ?Imagine if the global economy collapses, your head office calls, and tells you to shut down for 3 months... now what do you do? ? HVC Business Improvement Initiative Why did we need help ? External Events ? How we responded ? How we worked with Westwind ? Alignment ? Priorities ? Coaching ? Focus Groups ? Innovation ? What worked / Opportunities ? Questions

Nov 1, 2011

By B. D. Thompson

Many mines adopt necessarily conservative backfilling strategies due to a lack of understanding of their backfill behaviour. In the past five years, extensive instrumentation campaigns have focused on measuring in-situ cemented paste backfill behaviour. These tests have resulted in optimised backfilling efficiency through elimination or reduction of cure periods where; i) controls on backfill behaviour are understood, and ii) barricade pressures are demonstrated to be within a safe range using routine monitoring as a required QA/QC procedure. Recently, this work has been extended to consider hydraulic backfill operations. Two stopes have been instrumented at Vale?s Coleman and Garson Ramp mines. The instrumentation and deployment methods are discussed, and representative total earth pressure, pore pressure, and temperature data are presented. In one case, pressures in the stope are relatively low as drainage causes strength gain in the fill and so pressures are arched. In a second example, again, drainage causes strength gain in the fill, but increasing temperatures correlate with pressure increases even during downtimes in filling. These pressure increases are thought to be caused by thermal expansion of the backfill in confined locations. Generally, the instrumentation approach has proven successful in measuring hydraulic backfill behaviour and offers good potential for incorporation into a procedure to safely maximise backfilling efficiency through routine barricade pressure monitoring, when combined with safeguards to ensure adequate fill drainage.

Aug 1, 2013

By X. Cao, X. -G. Chen, K. Liu

As is well known, the standard Al-Cu 206 cast alloys have extremely low iron contents, usually less than 0.15 wt. %. Recently it is found that the iron contents of the 206 cast alloys can be extended up to 0.5 wt. % through the precise control of the iron-rich intermetallic phases. In the present work, the tensile fracture surfaces of the 206 cast alloys with various iron contents are systematically analyzed to understand the failure mechanisms. Results show that higher iron contents can reduce the tensile properties (especially the ductility) of the alloys mainly due to the increasing volume percent and size of the iron-rich intermetallics. Tensile failure mainly occurs at the iron-rich intermetallics/matrix interfaces for the platelet ß-Fe, but by the self-disassociation for the Chinese script a-Fe and Alm(FeMn). Cracking is easier to initiate and propagate along the longitudinal axis of the platelet intermetallics, but it can be deflected along the branches/arms of the Chinese script iron-rich phases, making the alloy more resistant to the propagation of the cracks, and thus the Chinese script iron-rich intermetallics are less harmful than platelet ß-Fe. In addition, it was also found that the Chinese script a-Fe has even a less damaging effect compared to the Chinese script Alm(FeMn) due to the relatively small size and compact morphology.

Jan 1, 2014