Search Documents

By Mahmoud Shakeri1

Various types of thin-walled structures have been frequently used as energy absorbers to mitigate the adverse effects of impact and hence protect the vehicle structure under consideration when subjected to different loading conditions. Compression tubular structures that buckle in a progressive manner, can be used to advantage, providing inexpensive and versatile, but nevertheless weight and stroke efficient energy absorbers. In this paper quasi-static nonlinear finite element simulations are performed to study the effects of number of corners of the cross-section, wall thickness, plastic hardening rate of material, foam-filler and load angle on deformation mode and mean crushing force of tube. Crush strength increases as the number of corners of the cross-section increases, though it almost saturates for the number of corners beyond 11. Higher plastic hardening rate stabilizes the collapse pattern. Foam-filled tubes seem to have higher critical load angles in oblique loading and display a more stable and gradual decrease in mean load over the transition region. Substantial decrease in the initial peak load and dynamic load at any a given deflection was observed as the load angle increases. The investigation of bitubal arrangements and Multi-cell tubes reveals that these may be preferable to monotubal specimens due to the presence of the inner profiles. In addition, a comparison is conducted between the numerical and experimental results of the mean forces of some special angle elements. Good agreement is obtained.

Oct 1, 2011

By Loris S. Pascoli

The increased pace of globalization in the mining industry has presented more opportunities for Canadian service companies to participate in ventures abroad. However, varying cultures, laws, competitive environments and contracting philosophies in other countries make it impossible to take for granted what is normal in the Canadian context. The author discusses some of his experiences and situations encountered in over 30 years in the diamond drilling industry, the last third of which were primarily focused on projects outside of this country.

May 1, 2001

By G. C. Laurence

"This paper discusses the hazards and extensive precautions taken in Canadian uranium mines, concentrating plants and processing plants. It also outlines Canadian policy regarding the control of the sale and distribution of uranium and other nuclear materials.OVER THIRTY YEARS AGO, I spoke to The Canadian Institute of Mining and Metallurgy here in Montreal about radioactivity and its dangers. I must have made quite an impression thirty odd years ago, because now you have asked me to do it again. Of course, the picture has changed. Then they were mining uranium ore, recovering the radium from it and throwing away the uranium. Now they are still mining uranium ore, but are throwing the radium out on the tailings dumps. Thirty years ago, most people did not know what ""radioactivity"" meant. Nowadays, they have beard that it is dangerous, and some of them, recently, be-came worried about the radium in the tailings dumps and what becomes of it."

Jan 1, 1969

By B. Galy, L. Giraud

"This paper compares Canadian provincial mining safety regulations addressing hoist safety, automatic hoisting, and shaft obstruction. The regulations are quite similar among provinces, with only slight differences. Risk-mitigation strategies used in other industries are discussed, including their applicability to mine hoists. The specific case of software safety is introduced through examples. The mitigation of software failure is based on the use of the software lifecycle as recommended by the International Electrotechnical Commission (IEC) 61508 standard. Finally, ways to improve hoist safety are proposed.RÉSUMÉ Le présent article compare entre elles les diverses réglementations provinciales canadiennes concernant la sécurité des machines d'extraction, le levage automatisé et les obstructions dans les puits. Les réglementations sont assez semblables entre les provinces, mais elles comportent de légères différences. Les stratégies d’atténuation des risques utilisées dans d’autres industries sont abordées, incluant la possibilité de les appliquer aux treuils de mines. Le cas spécifique de sûreté des logiciels est abordé par des exemples. L’atténuation de la défaillance des logiciels est basée sur l’utilisation du cycle de vie du logiciel, comme cela est recommandé par la norme 61508 de la Commission électrotechnique internationale (CEI). Des moyens d’améliorer la sécurité des treuils sont également proposés."

Jan 1, 2016

By K. A. Hughes

Under the oxidizing conditions of the McClean Lake Tailings Management Facility (TMF) hydrocarbons entrained on the surface of tailings material from mill processes are gradually converted to soluble bicarbonate ion. This has been observed to be a process occurring over approximately three years likely encouraged by the presence of a microbiological community within the tailings mass and in the water column. A recent tailings sampling campaign has provided evidence that bicarbonate ion is participating in the conversion of gypsum to calcite. In older tailings, equilibrium with calcite appears to be controlling the terminal bicarbonate ion concentration.

Aug 1, 2010

By M. J. Baker

Energy and Minerals Australia Ltd are undertaking a study of the recovery of uranium from the Mulga Rock Deposits in Western Australia. Approximately 80-90% of uranium identified to date is present as tabular layer up to 5 m thick within a lignite seam 30 m to 50 m below surface. Other metals are also present. Metallurgical studies at ANSTO Minerals laboratories in Sydney have focused on identifying a suitable uranium leaching process and assessing the possible downstream impacts of the organic material in the ore. The extraction of other metals has also been examined. This paper provides the results of testwork performed at ANSTO to date.

Aug 1, 2010

By C. G. Kemsley

THE ore as hoisted is very wet, and difficulty was experienced i~ screening it to remove the fines before going to the secondary crusher. In fact, the fines had a tendency to form balls and roll down the screen, and only a small percentage was removed. Their inclusion with the other ore going to the Symons secondary crusher caused excessive spring action and pounding between the adjustment ring and main frame, resulting in abnormal wear between the two. To overcome this, it was decided to wash the fines through the primary screen, and use an Akins classifier to de-water the screenings, pumping the overflow from the classifier up to the mill and discharging the oversize onto the mill-feed belt.

Jan 1, 1945

By A. D. Akerman, D. D. Young, G. R. Baiden

The development and maintenance of underground roadways are increasingly important aspects of the modern mining process. With the trend toward automation and track-less mining, roadbeds capable of with standing increased wheel loading have proven necessary to maintain high vehicle speed and reduced maintenance costs. Concrete has been used successfully on some roadways in order to obtain the required characteristics. However, this solution usually involves unacceptable expense. The objective of the Road Router project was to create a drift floor profiling machine capable of cutting a smooth surface out of the existing rock floor of development drifts and ramps. This surface would provide a durable, high strength, low rolling resistance roadbed that would allow for reduced operating cycle times and lower maintenance costs of scoops and haulage trucks. The Road Router has the potential to offer an alternative to concrete with substantial cost savings.

Jan 1, 1997

By Alan Bauer

IN RECENT PAST YEARS, the mining industry has expanded rapidly and mining engineers have not been generated in sufficient numbers to sustain this growth. Canada has not been alone with this problem, which has resulted in considerable soul-searching as to what the solution might be. Because of the unfavourable economics of running small departments such as mining, metallurgy, ceramic engineering, etc., one approach in some cases has been to put these departments together to form a department of mineral science which now has a broader base structure. Another solution has been the "conversion kit" program which has been conducted both at universities and in industry. At universities, such programs have consisted of converting graduates of other engineering disciplines into mining engineers. In some of the large mining corporations, extensive training programs have been used with the same aim.

Jan 1, 1972

By I. M. Santos Moraes

The control of minor impurities (mainly As, Sb and Bi) in copper refineries has been a great challenge. Caraiba Metais' copper refinery produces a very high quality copper, registered in LME as grade A, and recognized as amongst the top ten in the copper world. At Caraiba's Tankhouse Bi and Sb are controlled by means of electrolyte bleed-stream removal after partial decopperizing in a set of electro-winning cells (liberators). Another way of reducing the Sb and Bi content in the electrolyte is by means of the arsenate precipitation chemistry. It is well known that the use of high arsenic concentrations in copper refinery electrolyte has the advantage of causing most of the bismuth and antimony to report in the anode slimes. However, the use of such mechanism of control may contribute to other undesired problems such as antimony and bismuth precipitation in the bulk of the electrolyte, what may cause severe contamination problems. This paper describes a period when some cathode contamination with Sb occurred at Caraiba Metais' Copper Refinery. It also presents an analysis of several process parameters related to the problem, the possible causes for the contaminations as well as the actions taken to correct the problem.

Jan 1, 2007

By M. Stelter

Since the first years in copper electrorefining natural products have been used as so called "additives" in the electrolyte. Glue as one of these additives offers a lot of different reactions with the metal ions and also with other additives like thiourea in the electrolyte. For a deep understanding of the effect of these additives it is important to know the routes of possible reactions in the electrolyte as well as the basics of electrocrystallization. Using this knowledge the interpretation of nodulation or inclusions of electrolyte in the cathodes in copper electrorefining is easier than before. Setting up on physical and chemical properties of the electrolyte and the additives practical investigations of the effects of additives in copper electrorefining and their impacts on copper crystallization and cathode quality are presented in this paper. Chemical deposition of glue against time and temperature are only few of the effects that are mainly caused by the use of natural products. In fact parameters like anodic and cathodic polarization are strongly affected by the additives as well as the effects of the additives are strongly affected by current density. This second part of the paper presents results concerning interactions of the above mentioned parameters.

Jan 1, 2007

By J. L. Casado-Sánchez

Financial capital is highly volatile and if the investor does not get adequate compensation for the risk faced he may consider withdrawing his capital assets from the company and consequently produce a structural change in any sector of the economy. We study the variation in profitability of assets in terms of the changes that occur in the markets. The choice of models used is justified by the extensive theoretical and empirical use of them throughout the history of financial economics. We have used the capital asset pricing model (CAPM) and the model based on the arbitrage pricing theory (APT) to determine the beta value. These models have been applied to the monthly returns of 27 mining companies listed on the New York Stock Exchange (NYSE) or London Stock Exchange (LSE), using data from the period covered from January 2006 to December 2010. The results of time series and cross sectional regressions for CAPM and APT produce some errors, suggesting that many companies have failed to obtain an adequate cost of capital. Also the results show that higher risk firms tend to have lower profitability. These findings make it unlikely to be maintained over the long term the current status and could drive structural change in the mining sector in the form of mergers.

Aug 1, 2013

Innovation ? In economics a change must increase overall value, customer value, or producer value. ? Innovations are intended to make someone better off, and the succession of many innovations adds growth to the whole economy. ? Innovation may refer to both radical and incremental changes to either products, processes or services.

Feb 1, 2008

By J. G. Ross

A DESCRIPTION of the block-caving system of mining as practised at the King mine of Asbestos Corporation, Limited, Thetford Mines, Que., was presented. at the Annual Meeting of the Institute held in Quebec city, in April, 1934. The paper was published in the Transactions of the Institute for 1934. There has now been recovered, by this method, one million tons of ore, and a review of experience indicates that the method was well planned and has been executed smoothly. In approaching the problem of selecting the type of mining best adapted to this deposit, the method had to be one which would be low in cost, use no wood, and not disturb the surface immediately bounding the ore-body on two sides. Prior to 1931, block-caving had been considered but rejected, as it en-tailed disturbance of the surface area which lay within a 45° angle of the lowest contemplated workings, if the practice of such mines as Ray, Miami, Inspiration, and Morency, where this type of mining has been used extensively, was followed. At these properties there have been mined large tannages at outstanding low costs, but an extensive surface area has been disturbed in each case. In some instances, townsites in the mining area have had to be abandoned, and dwellings, not considered worth moving, have been allowed to fall into the depression. A study was made of the principles involved in the various types of block-caving, the existing information on ground movement, subsidence, etc., also being carefully analysed. Toward the end of 1931, a plan was conceived whereby the country adjoining ground being caved might be held permanently in place and undisturbed. The success of such a scheme was essential to the application of block-caving at the King mine on account of property boundaries, the Quebec Central Railway right-of-way, and expense of moving buildings. Study of existing data on caving and movement of rock, caused by sub-surface excavations of sufficient unsupported area to result in failure of the backs, indicated, in practically every instance, that such movements followed certain definite laws of mechanics.

Jan 1, 1936

By J. E. Moran

A groupd of French capitalists, La Compagnie Française des Mines d'Or du Canada, has undertaken the considerable task of developing Otter creek, in the Atlin district, B.C., by hydraulic mining methods. It has long been known that the gravels of this stream carry sufficiently high values in gold to make it attractive as a mining venture, but it was impossible to ignore the existence of formidable natural obstacles to hydraulicing them, and these needed to be taken into serious account before embarking upon any costly programme of development. The tide to the Otter Creek leases was originally held by Mr. H. Maluin, a French engineer well known throughout the north, to whom was to fall the task of financing whatever programme might be decided upon. It was he, too, who would have to assume the responsibility of finally passing judgment upon the practicability of the various devises for overcoming the adverse natural conditions. With an infinite attention to detail, which I believe to be a characteristic of the French people generally, he studied his problem and was finally able to submit to his financial backers a programme which left the very minimum possible to the hazard of accident or chance. Dr. Mandy, on his visit to Otter creek this season, expressed the opinion that our method of opening this difficult creek presented certain features which might be successfully applied in placer operations elsewhere in British Columbia, and it is largely for this reason that the present paper has been prepared. I shall set forth, as well as I can, the practices which have enabled us to overcome rather easily some of the obstacles which nature had unkindly placed in the path which we must take. The natural flow of water in Otter creek is far too little to deal success-fully with the rather excessive amount of glacial drift overburden which lies directly over the gold-bearing gravels. For this natural defect, the only remedy was to procure more water. This we have clone through a system of flumes and ditches, totalling between ten and eleven miles in length, which bring to the mine a supply of water adequate for our needs.

Jan 1, 1932

By J. B. Evans

"THE OPPORTUNITY to participate in a CIM seminarconcerning the direction of mining engineer trainingis perhaps fortuitous as it comes at a time when theengineering schools which have invited inspection byCanadian Accreditation Board of the Canadian Councilof Professional Engineers are examining theirrespective curricula.Currently there exists considerable soul-searching in various engineering schools across Canada where questions such as the following are being posed.- Have we achieved the correct balance between subjects related to technical methodology and subjects devoted to conceptual planning and design?- Should we include ""applied humanities"" in our program? (Whatever ""applied humanities"" might mean!)- Should courses covering pollution control, ecology, economics, technical writing, professional conduct and ethics be offered as compulsory subjects, as electives, or not at all?- Is it a better scheme to have students complete an Arts or Science degree before entering engineering?- Do we place too much emphasis on pure mathematics and sciences with the result that insufficient time is available for instruction in the engineering applications of these subjects?- Should English expression and/ or literature be included in the engineering programs and, if so, should these subjects be presented by the English department or by English lecturers captive to the engineering school? - Is the present program directed primarily at research activities rather than preparing engineers for their future roles in industry? - Should we teach our own versions of mathematics and physics? - Do we have sufficient engineers on the faculty strength or are we overloaded with Ph.D.'s from the pure sciences? - How flexible should the program be, what should the compulsory vs elective course content be, and what freedom of choice, if any, should be given with respect to elective courses? - To what extent should students contribute to faculty decisions?- How far should we pursue computer science subjects and do we need to make our students proficient in computer programming? - How far should operations research and mathematical models be carried in the undergraduate program when the students have limited experience in the real engineering world? - Realizing that an engineer never completes his education, should the undergraduate program cover ""bare bones"" engineering and should instruction in particular disciplines be left to graduate schools and / or industry?"

Jan 1, 1972

By A. Boucher, D. Marcotte

"Abstract- The accepted practice for the estimation of thin (2D) vein deposits recommends the use of the grade x thickness service variable (i.e., the accumulation). Grade estimates are obtained indirectly by the estimated accumulation/estimated thickness ratio. This practice stems from the varying support (thickness) problem and the resulting non-additive nature of the grade variable. We compare the actual performance of the direct grade estimation approach used by some practitioners to that of the indirect approach using accumulation. Our simulated and real data indicate that the direct approach is more accurate for point grade estimation where the grade-thickness correlation coefficient is positive (and vice-versa). Moreover, the relative gain of the direct method increases with the (positive) correlation coefficient. This finding contradicts common thinking that the indirect approach should be the preferred method where grade-thickness correlation is strongly positive. Also, for a given positive grade-thickness correlation, the relative gain of the direct method increases with the coefficient of variation of the grade and thickness. Résumé - L’estimation de veines minces (2D) minéralisées est normalement réalisée à l’aide de la variable auxiliaire épaisseur x teneur (i.e., accumulation). Les estimés des teneurs sont alors obtenus indirectement du rapport accumulation estimée/épaisseur estimée. Cette pratique découle du problème du support variable pour la teneur, l’épaisseur de la veine, qui fait que la teneur est alors une variable non-additive. Nous comparons les performances de l’estimation directe de la teneur, utilisée par certains praticiens, à celle de l’approche indirecte. Pour l’estimation ponctuelle des teneurs, nos données simulées et réelles indiquent une meilleure justesse de l’approche directe quand la corrélation teneur-épaisseur est positive (et vice-versa). De plus, le gain relatif de la méthode directe s’accroît avec la valeur de cette corrélation (positive). Ce résultat contredit l’opinion répandue que l’approche indirecte devrait être utilisée en présence de forte corrélation positive de la teneur et de l’épaisseur. Nous montrons également que pour une corrélation positive teneur-épaisseur donnée, le gain de l’approche directe augmente avec les coefficients de variation de l’épaisseur et de la teneur."

Jan 1, 2001

By Kevin S. Borthwick

The subject of this paper is a facility wide Distributed Control System (DCS) upgrade being completed at a large copper and molybdenum mine. This paper will discuss the innovative hardware and software technologies employed in the new control system. This paper will also describe the planning process, migration path and simulation techniques used to ensure the success of such a large and complex DCS upgrade.

May 1, 2008

By M. Bertrand

Oxalic precipitation is usually applied to process radioactive wastes or to recover actinides from a multicomponent solution. Precipitation reactions being highly sensitive to many operation parameters, the computer simulation appears to be a very effective tool to forecast the evolutions of the system subjected to various operating conditions. This study focuses on the tetravalent uranium oxalate precipitation modelling which combines population balance and hydrodynamics. Both experimental and numerical studies are carried out in order to analyse the reactor design influence on the precipitate characteristics. The simulations taking into account primary nucleation and crystal growth are in agreement with experiments.

Aug 1, 2010

By J. Bourgeault

Modem civilization is indebted to that most ancient of the skilled crafts - the art of stone working, as the one consistent means whereby the dim un-recorded past has conveyed to our modem schools of science volumns of facts, written in characters of imperishable stone. Although left, centuries ago, to ruin and decay, architectural examples of the ancient building crafts still remain to the glory of the old master-builders, whose accomplishments in that remote age continue to influence and inspire their modem successors. Present-day architects and builders will leave to posterity just as faithful a record of our modes of living and of the methods now adopted for protection, as if it had been made by written word; and our craftsmen have profited greatly, in meeting modem requirements, by taking advantage of the indurance and utility of stone. Stone in all ages and stages of the world's civilization and development has been the material chosen by the masterbuilder, the one material possessing qualities that render it most desirable in affecting the artistic ideals of each period. It perfects the science of architecture through its durability and thus renders possible the study of man's workmanship in stone throughout periods of civilization of which we have no specific written account. Other materials have been used for the construction of man's habitations, but none have withstood the test of time, nor have established the credit of designer and builder so well as stone. _All other materials fall into ruin and decay, leaving neither mark nor monument for the enlightenment of mankind.

Jan 1, 1925