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By Timo Heikkinen

We have read, with great interest, Mr. Crocker's article on "Recent Trends in Autogenous Grinding," published in the October issue of The Canadian Mining and Metallurgical Bulletin. Referring to our paper, "Two-Stage Autogenous Grinding Investigations at Outokumpu," we can now report that last August we changed to this method at the Keretti concentrator. Prior to the conversion, the Keretti plant (see flow-sheet, Figure 1) had two primary rod mills, 6 ft. in diameter and 12ft. in length, in open circuit, followed by four secondary 9-by 12-ft. pebble grate mills in closed circuit with rake classifiers. Last summer, wl1en the Since August, grinding has been successfully carried out autogenously in two stages, with two mills being employed in the primary stage and four in the secondary. The size of the pebbles in the secondary mills is about the same as earlier -l V: i to 3 inches (Figures 4 and 5). Also, we generally prefer two-stage grinding to single-stage grinding because, in the former,

Jan 1, 1964

By C. T. Harper, B. J. Fryer, R. P. Taylor

"IntroductionThe Maurice Bay deposit is one of a number of uranium deposits that have been found in recent years in the Athabasca Basin of northern Saskatchewan (Tremblay, 1982). This deposit, along with the others, belongs to the unconformity type deposits (Beck, 1977). They are, for the most part, polymetallic, being characterized by a suite of metals which include U, Ni, Co, Cu, Pb, Zn, Mn, V, Ag, Au, Pt-group elements, S, As, Bi, Se, Te, and Mo, some of which, besides U, are present in economic concentrations (Amok, 1974; Ruzicka, 1975; Tapaninen, 1976; Hoeve and Sibbald, 1978; Dahlkamp, 1978). The Maurice Bay deposit was known to be a small low grade deposit in which the ore was essentially monomineralic, consisting mainly of pitchblende (Harper, 1978). However, the occurrence of trace amounts of some of the elements common in the larger polymetallic ore bodies (e.g. Key Lake, Cluff Lake D) was anticipated. Thus a lithogeochemical sampling project was undertaken in 1979 across part of the Maurice Bay deposit (Harper, 1979). Major oxides (SiO2, Al2O3, FeO, Fe2O, MgO, CaO, K2O, Na2O, MnO, P2O5, and TiO2) and a group of the most common trace metals (U, Ni, Co, Cu, Pb, As, Au, V, and Se) were analyzed to determine whether any elemental patterns (halos or depletions) could be detected which would reduce the number of pathfinder elements needed for exploration purposes. In addition to the above metals, Th was also checked because some conglomerate strata in the Maurice Bay area are known to be thorium-enriched (Harper, 1978). Only the trace metal distributions will be discussed in detail in this report.General GeologyThe Maurice Bay area is underlain by three major groups of rocks, the White Lake metamorphic complex, an unnamed granodiorite complex, and the Athabasca Group, described previously (Fig. 1; Harper, 1979). Table 1 summarizes the stratigraphic features as deduced by geological mapping and the examination of drill cores."

Jan 1, 1986

By B. S. Kim, Y. D. Kim, T. S. Kim, T. B. Kim, H. J. Chae

"The Nd-Fe-B scrap was placed in Fe crucible with pure Mg in an Ar atmosphere, and the scraps were melted using an induction heating method. The effects of experimental parameters such as melting temperature (range of 993K to 1073K) and holding time (15min-600min) on the ability of extraction were investigated. The microstructure and diffusion layers were analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), and the constituent phases were characterized using XRay Diffraction (XRD). Diffusion of Nd through the Nd-Fe-B scrap into liquid Mg was described, and the diffusion coefficient of Nd in liquid Mg was estimated.INTRODUCTIONNd-Fe-B magnets are usually produced either from comminuted melt-spun ribbons as bonded magnets or hot pressed bulk magnets, or by sintering in conjunction with prior green compaction in an applied magnetic field (Sagawa et al., 1984). These magnets have been widely used for various electromechanical and electronic devices such as voice coil motors (VCMs) and magnetic resonance imaging (MRI) (Samardzija et al., 2012; Matsuura et al., 2006). The production of the Nd-Fe-B magnets is increasing by about 20% per year because of their excellent magnetic properties. However, the expansion of Nd-Fe-B magnet market induced a concern for the scarcity of Nd at the aspect of natural resource. Therefore, the development of an effective recycling process for Nd-Fe-B magnet scraps is an extremely important issue from the viewpoint of resource and energy conservation. Several recycling processes for the Nd-Fe-B magnets have been proposed (Uda et al., 2002; Lyman et al., 1993]. It has been reported that the best separation of rare-earths from the Nd-Fe-B magnets is obtained by sulfuric acid dissolution followed by precipitation of recyclable rare-earth salts. However, this process can make a large amount of waste water including dangerous solutions. Recently, (Xu et al., 2000) have reported a technique to extract Nd from 18Nd-72.4Fe-0.9B-1.82Pr-5.3Dy (wt.%) magnet scrap by using liquid metal extraction (LME) processing. However, these techniques seemed to be difficult for application, because the scraps consist of an infinitesimal amount of other minor elements (Pr, Dy, Cu, Al and Tb), and these minor elements can make a new intermetallic compounds with Mg. Also, some oxides or the plated Ni metal can be preventable to reaction between solid-liquid (S/L) interfaces. For these reasons, the substantive reaction mechanism between Mg and Nd-Fe-B scrap is not clear. In this study, the simple composition of 33Nd-66Fe-1B (wt.%) magnet scraps were prepared using an induction melting process. The effects of the experimental parameter on the diffusion properties between Mg and scraps were investigated to determine whether these methods could be used in industrial application in a liquid metal extraction (LME) process."

Jan 1, 2012

By J. F. J. Thomas

"AbstractBoth the quantity and quality of waters available as raw materials are important to Canadian industry and to the national economy. The huge demands of many Canadian industries is illustrated by tabulated figures, based on the 1950 Canadian production of certain products, and on United States figures for the gallons of water required to produce a unit quantity of each product. It is suggested from comparison with American survey results and figures that Canadian industrial water consumption is 1 to 11/2 billion Imperial gallons per day. Since present information on Canadian usage is meagre and it is not certain that American survey results can be directly applied to Canadian industry, this estimate must await confirmation in future studies.The hydrologic cycle and the principal factors affecting the quantity and quality of water, namely, climate and season, topography, geology, vegetation, and human activities, are discussed and the principal salts dissolved in water which affect industrial use are enumerated.The present survey studies by the Mines Branch on water quality are outlined. Besides chemical analyses of municipal water supplies within a watershed, periodic sampling and analyses of major surface waters for a one-year period is being carried out. The importance of studies on seasonal variation in quality is stressed by comparing the dissolved salts in various river waters with river flow. Figures showing such relationships in the Rideau river and Ottawa river at Ottawa, the Columbia river at Trail, B.C., and the Battle river at Unwin, Sask., are presented. Different rivers show different quality changes with changing flow, and possibly only after long-term studies can the relationships be predicted.Quality studies on water may be as important as studies on many other raw materials. The quantity of the raw material, water, is not inexhaustible nor is the quality indestructible, and more realization of its importance, followed by conservation and intelligent use, is desirable."

Jan 1, 1952

By H. J. Handewith

"After having performed qualitative and quantitative tests on nearly 550 rock specimens from tunnel projects throughout the world and comparing the results with actual boring in eight distinctly different rock types which varied in compressive strength from 12,000 to over 34,000 psi, it has been concluded that any rock -andesite, granite and even taconite -can be machine-bored. The question is -can it be bored economically? The intent of this paper is to delineate the investigative needs to accurately and reliably answer this question. A piece of NX core in the hand represents less than 50 per cent of the worthwhile geologic information that could have been obtained from a given core hole. A thorough site investigation by competent personnel can gene-rally foretell to what extent, if any, varying geologic conditions will hinder machine progress.A laboratory testing technique has been developed that has been correlated well (80 to 120 per cent) with actual boring results. This technique will be discussed in detail. Rock cutter life is a function of the penetration rate and the forces required to sustain that rate. Cutters are now, and will be for .some time to come, the single, most expensive consumable item involved in continuous tunneling in hard rock. It is by strict attention to predicting these rates and forces that tunneling costs can be optimized."

Jan 1, 1970

By The Staff

"THE Wabana iron ore mines, owned and operated by the Dominion Steel and Coal Corporation, Limited, .are on Bell Island in Conception bay, on the east coast of Newfoundland. Mining began on surface in 1895 and, although open-pit work is still done on a small scale, the entire output may be considered to•be derived from extensive submarine workings. In 1958 the average daily production of hematite ore was close to 12,000 tons, almost all of which was concentrated in a heavy-media plant. SUMMARYThe character, occurrence, and extent of the submarine bedded deposits enabled early operators to meet prevailing market demands with the minimum attention paid to exploration. Mechanization of the mine and the pressure for sustained high tonnages since 1955 have emphasized the importance of an expanded exploration and development programme.A serious handicap has been the impossibility of utilizing normal diamond drilling methods to explore ore conditions in advance of mining faces. Drilling between tl1e bedded zones has been done but the major difficulty has been to delineate ore reserves in the lower bed, which has the greatest ore potential of the three mineable seams."

Jan 1, 1960

"The Crescent, DM, and Pothook zones are copper-gold porphyry deposits which formed in association with alkalic intrusions of the early Jurassic Iron Mask batholith. The characteristics of the Crescent and DM deposits are nearly identical. Both formed along the contact between the Cherry Creek monzodiorite and Pothook diorite phases of the batholith. Permeable intrusion breccias along the contact concentrated the flow of hydrothermal fluids. Early, pre-ore alteration is represented by pervasive, sulphide-barren potassium metasomatism. The precipitation of copper-gold ore occurred during subsequent fracture-controlled potassic alteration, and is most strongly developed in chlorite-sulphide veins and their alteration envelopes. A central zone of potassic alteration is surrounded by a propylitic, pyritic halo in both deposits. The DM zone is unique among alkalic porphyry deposits in its high abundance of quartz-sulphide veins.The Pothook deposit formed at the westernmost contact of the Iron Mask batholith with enclosing Nicola Group volcanic rocks. Pervasive potassium metasomatism, similar in style to that at Crescent and DM, is associated with intrusion of the Cherry Creek monzonite. Pervasive and fracture-controlled albitic alteration is associated with intrusion of the Sugarloaf diorite and introduced minor copper-gold mineralization. Most of the copper-gold mineralization was introduced during formation of veins and breccia matrices dominated by magnetite/hematite and sulphide. Late-stage chlorite veining may have remobilized or introduced additional gold mineralization.Copper and gold assays in the Crescent deposit are well-correlated and have a nearly constant Cu:Au ratio, suggesting that the metals coprecipitated during a single hydrothermal event. In the Pothook deposit, copper and gold do not correlate closely, lack spatial correspondence, and suggest that transport and/or deposition of the two metals were not identically controlled and that they may have been introduced at different times by separate hydrothermal events."

Jan 1, 1995

By Leslie Gertsch

Outline First progress report ? ?Introduction ?Non-terrestrial mining ?Near-term targets ?Stages of mining ?Study procedure Capabilities needed for non-terrestrial mining ?Mining methods ?Mining unit operations ?Typical surface mine operations sequence ?Results to date General effects of gravity ?On fragmentation ?On excavation ?On transport ?Conclusions / Recommendations

May 1, 2013

By L Munholand, G. Soucy, P. Quintal

This work presents early results from the first study to optimize the hydrodynamics of a Plasma Lift Reactor (PLR). The PLR is designed to break down organic contaminants in aqueous solutions. New experimental results are presented for air/water tests and for plasma degradation of organic contaminants in Bayer liquor. In addition, a multiphase Computational Fluid Dynamics (CFD) model has been developed which predicts the hydrodynamic behavior in the PLR. These results of this work suggest the PLR is effective at reducing contaminants in the Bayer liquor and that the CFD model adequately describes the hydrodynamic flow.

Jan 1, 2005

By T. G. Joseph

ABSTRACT: The Canadian oil sands provide some of the harshest mining conditions in the world. Asoperations demand ever bigger tools, the toll on large mobile mining equipment is high, with structurallife often half of that expected. Soft ground conditions predominantly lead to fatigue failure scenarios, poor stability, and inconsistent payload evaluations. These challenges are not solely a concern for Canadian oil sands mines; there are far-reaching implications for surface mining equipment in any poor ground-operating environment. This paper focuses on the basics of payload evaluation, motion response and a simple estimate of structural life for haulers.

Jan 1, 2011

By G. A. Vissac

IN THE preliminary design of a coal washery, the most important factor to evaluate is the ash content of the final product. The ash content permissible may be imposed by market demands, but, in the final analysis, sooner or later - as most consumers today are buying coal on a 'heat value' basis - the coal operator has a certain margin of latitude. and the ash content of the coal to be delivered can be determined on the basis of maximum returns and highest profits. A few years ago, the most desirable separation was selected on the basis of the plus-minus 0.10; that is, the most desirable gravity of the separation was selected at the point showing a minimum amount of near gravities in the raw coal. The reason for this was an expected wide error over these near gravities. Today with the recent development of cry accurate, automatically controlled cleaning apparatus, a much larger latitude is possible, and the most desirable gravity of separation can be selected, almost exclusively, on the basis of the economic factors involved. To illustrate these new methods of investigation we shall give two examples, based on actual coals from the western United States.

Jan 1, 1957

By P. Trudel, M. A. . Cloutier

This lithogeochemical study demonstrates that the Gilman and Blondeau Formations in the Chibougamau area belong to a subalkaline suite of tholeiitic affinity poor in potassium. The Gilman Formation is composed mostly of basalts, with subordinate andesites and rare dacites, while the Blondeau Formation comprises all lithologies of the basalt-andesite-dacite-rhyodacite-rhyolite ensemble. Both AFM and Harker variation diagrams show that all these rocks originated by differentiation from the same magma reservoir, and are related to one volcanic episode, This study did not, however, identify hydrothermal alteration zones useful for regional geochemical prospect ion.

Jan 1, 1984

By E. Dernedde

Cell rooms of aluminium smelters have large openings in the sidewalls and in the roof. These openings provide a high ventilation rate, which removes heat and contaminants emitted by the reduction cells and thereby ensures acceptable working conditions inside the cell room. However the large openings make the airflows through the smelter building sensitive to the wind. In this study equations for the airflow through the openings of a smelter building exposed to crosswinds were developed and verified against plant measurements. The equations were then used to estimate the airflows through a two-storeyed smelter building containing VS Soderberg cells. Wind protection by wind-covers over the sidewall openings and by upwind buildings made the airflows through the building less sensitive to the wind. Physical and mathematical modelling showed that working conditions inside the wind-protected cell room would be acceptable for crosswinds at speeds up to 16 km/h. These predictions were confirmed by measurements taken in a VS Soderberg smelter.

Jan 1, 2007

By S. Gaulocher

Gearless mill drives (GMDs) are the workhorse in the mineral processing industries, more specifically when it comes to grinding crushed ore and cement (in various production stages) in semiautogenous (SAG) mills and large ball mills. They are renowned for their excellent reliability and robustness, long lifespan, and little need for maintenance, and thus yield a low total cost of ownership (TCO). A GMD represents a major investment for a mineral processing plant, and its availability is pivotal for the grinding process. As a basic rule, shut-down periods are to be minimized, but even much more important is that unscheduled shut-downs be avoided. In this contribution, we will present a portfolio of innovative remote diagnostic that consist of the following three key components: 1. Trouble shooting is a form of corrective maintenance and is based on state-of-the art remote access technology, thus enabling highly skilled engineers to access the current sensor readings anytime and from anywhere in order to resolve urgent problems together with the GMD user. 2. Periodic maintenance reports are a form of preventive and predictive maintenance and aim at continuous improvement based on long-term historical records and analyses of multiple measured signals. These detailed reports highlight the health and operational status of the GMD and are periodically (e.g. 3 months) submitted to the customer. 3. Remote condition monitoring spans across preventive and predictive maintenance and is based on continuous recording and automatic analyses of relevant signals using advanced algorithms. The main issue is how to handle the enormous flood of data in an intelligent manner. The results of these analyses are made available to both the GMD user and supplier in real time in order to increase the availability and reliability of the GMD. In this paper, we consider various parts of the GMD, e.g. the cycloconverter, the ring motor, the auxiliary devices (e.g. cooling and lubrication systems), and also phenomena related to the mill itself (e.g. state and quantity of charge). The signal analysis techniques range from simple threshold-based analyses to complex time and frequency domain analyses. We will illustrate the benefits of the proposed approaches with some selected examples.

Jan 1, 2012

By W. Dingley, G. R. Hoey

"Thirteen Canadian sulphide ore mines were surveyed for corrosion control. The mines visited were a small, yet representative, proportion of this segment of the Canadian mining and metallurgical industry. Information on metallic corrosion and methods used to control it in underground workings and mills was gathered (a) by discussing corrosion problems with company personnel, (b) by examining equipment and structures during under-ground and mill tours, (c) by photographing corrosion sites, and (d) by collecting and analyzing mine water samples.The corrosion survey, which is summarized in the re-port, leads to the following general conclusions. Mine environments are corrosive, particularly when the mine w1a-ter is acidic. Because of a lack of good corrosion control measures, excessive deterioration of equipment due to corrosion occurs in mines. Mill environments are also corrosive, but in some cases good preventive measures are being taken to effectively control corrosion losses.Ways to reduce corrosion losses in sulphide ore mines and mills are discussed. The main areas for more corrosion research and development are selection of materials of construction, protective coatings, cathodic protection, inhibitors, equipment design, and mining and milling practices."

Jan 1, 1971

By William B. Hetherington

Communities are the foundation upon which the whole structure of society rests and upon which the nation builds its hope for the future. They are not established to serve any one particular generation, nor any one element or group, but should be erected to render a lasting service to all who are to follow. They play a very vital and important role in the lives and welfare of the people, in their industrial, business, and social relations, and in the economy of the nation, of which they are the fundamental assets. Communities and civic governments are destined to be vital factors in the national welfare in the days that are to come. Any improvement in national or world conditions must have its origin within the communities. Any attempt at solution of the community problem must give some consideration to the fundamental elements which exist in every community, and to the underlying principles, and ways of life and thought, upon which community life is based. The community is, in its essence, a number of people living and working more or less closely together, sharing common rights, privileges, conveniences, and comforts, which would be impossible for the individual to obtain for himself by his own efforts alone, or in any other way than by the mutual exchange of persona! services and resources. In this way, men have increased the returns from their labour and commerce, have raised the standard of their living, with better social, educational, and recreational facilities, and enjoy a greater personal security.

Jan 1, 1943

By K. El-Ouassiti, M. Zouadi, C. Bazin, D. Hodouin

Data reconciliation techniques are used to attenuate the effect of measurement errors and estimate unmeasured variables. This paper illustrates the application of data reconciliation to hydrometallurgy processes using measurements from leaching and solvent extraction obtained from laboratory experiments. The application of data reconciliation provides an efficient way to detect gross and systematic errors and produces reliable performance indices for process evaluation.

Jan 1, 2005

By C. W. Drury

It is practically fifteen years since stellite was first introduced into industry, and since then the progress made in its manufacture has been so rapid and the number of successful applications so varied that it was considered a review of the more important phases would be of general interest. Stellite is a cobalt-chromium-tungsten alloy, containing approximately 2. 75 per cent carbon. The high percentage of carbon is necessary for the requisite hardness and resistance to wear at ordinary temperatures, whereas the tungsten is essential to impart hardness at a red heat. Chromium imparts hardness and strength, and cobalt renders the alloys more resistant to oxidation. The metals cobalt and chromium are completely soluble in all proportions, both in the liquid and solid state, the equilibrium diagram showing a minimum in the solubility curve at approximately 50 per cent cobalt and l,340°C. Cobalt and tungsten are completely soluble up to 40 per cent tungsten, which is beyond the limit of the; tungsten content of stellite alloys. In the presence of carbon, carbides are formed, which are essential in stellite possessing good cutting or wearing properties.

Jan 1, 1930

By Dean L. Millar

Measures taken by mining companies around the world to reduce their carbon footprints are becoming increasingly important in the sector securing its social licence to operate. The options for measures reduce to three categories of activity: i) demand reduction by avoiding unnecessary waste of supplied energy, ii) improving the utilization of energy that does have to be consumed and iii) adopting low carbon energy production options?including renewable energy. As well as the environmental imperative, as the prices of electricity, gas and liquid fuels increase, so the economic case for activities i) to iii) gains higher priority, especially in such an energy intensive industry. The specific energy consumption for certain upstream minerals industry operations in Canada is reported to be as follows: underground mining: 99.5 kWh/tonne mined; surface mining: 11.7 kWh/tonne mined; base metal processing: 81.4 kWh/tonne milled; gold processing: 99.6 kWh/tonne milled. Around 508 kWh/tonne (slag) of heat is reported to be available in cooling slag from 1500°C to 25°C; an amount that is simply indicative of the energy intensity of downstream smelting and refining operations. Low carbon, energy saving technology options that are available to mining industry companies lead to projects with return rates that must compete alongside other capital intensive projects considered by mining company boards. Energy projects frequently involve longer payback periods and lower rates of return than those of competing bids for capital, such as those for development of new mineral properties. For energy services companies (ESCOs) that specialize in the financing, construction, and the efficient operation and maintenance of energy projects, the same returns and payback periods may be considered acceptable or even attractive. For the ESCO, the key commercial risk mitigating factor is a securing a long term contract for the supply of energy.

May 1, 2011

Pilot plants for pressure hydrometallurgy represent special design and project execution challenges unique to the industry and to the pilot- and demonstration-scale. Pilot plant projects have different objectives and shorter timescales than commercial plant projects. Design considerations and strategies, and project execution methods that meet the special needs of pilot plant projects, are discussed. Specific guidance is given for the selection of appropriate pressure and temperature design points for pressure hydrometallurgical process equipment, and for the selection of materials of construction for pilot-scale equipment. The balance between the need for process similarity with future commercial operations and the realities of pilot-scale equipment is also discussed.

Jan 1, 2004