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By L. Trytten, S. Bass, P. Nawrocki, J. Mercer

The Sherritt Fort Site nickel refinery and fertilizer plant has been operating continuously since 1954. The ammonia leach process uses ammonia and sulphuric acid, producing nickel and cobalt and an ammonium sulphate byproduct. One of the features of an ammonium sulphate based process is the aggressive nature of ammonium sulphate to concrete and structural steel. After six decades of operation, portions of the structural steel and concrete at the Sherritt facility have become degraded. Infrastructure replacement programs started in earnest more than a decade ago with pipe racks and electrical infrastructure, and have now progressed into building steel. Replacing and repairing this infrastructure within the tight constraints of an operating plant poses several difficult challenges. This paper will outline the approach taken to accomplish this difficult work, and discuss key learnings from the ongoing program.

Jan 1, 2015

By D. Chakravarty, B. Samanta, D. Ghosh

Autonomous robots are useful for 3D underground mine mapping to avoid human exposure to hazardous spaces. To prepare a precise mine map, a self-navigating robot must navigate an arduous path, avoiding obstacles and sensing the environment. A prototype laboratory-scale robot was built and evaluated through a mock-up in a test mine gallery. It was outfitted with a 2D laser scanner, a stereo camera for obstacle avoidance, and a high-precision, laser-based imaging and digitizing system for collecting 3D point cloud data. Various algorithms were used for scan matching to facilitate simultaneous localization of the robot for mapping.

Jan 1, 2014

When selecting a method for monitoring crack growth in pipeline steel, the sensitivity or crack-size resolution plays a dominant role. Even though there are several visual and non-visual methods, the direct current potential drop (DCPD) method is very effective for monitoring crack growth because of its resolution. This method has been used for the past few decades and has gained increasingly wide acceptance in fracture research as one of the most accurate and efficient methods for monitoring the propagation of cracks. Furthermore, most R&D experience has proven that the electrical potential method can be used in most "aggressive" environments. For these reasons, the DCPD method was selected to design a testing machine to monitor corrosion fatigue crack growth. The use of finite-element modelling is shown to facilitate the application of the DCPD method for monitoring crack growth in steels. The 2D model calibration provided a good description of the test data and proved more accurate than the analytic Johnson's formula.

Jan 1, 2005

By J. B. Morrow

Methods of Coal Preparation Fundamentally, the object of coal preparation is to increase, economically, the value of a fuel by making it more suitable to the uses of the consumer. This can be accomplished in three major ways: 1.Screening or sizing 2.-Mixrng or blending 3.-Cleaning By combinations of any or all of these methods we can prepare coal to meet standard specifications-a process of standardization which is the more desirable the more nearly it approaches the unvarying quality of packaged goods, where the package you buy today and tomorrow is the same as that you bought yesterday. It should be noted that it is readily possible to get good cleaning and still have poor preparation because of faulty screening and mixing, and, on the other hand, it is possible to get a passable grade of cleaning, combined with good screening and mixing facilities.

Jan 1, 1931

By X. Cao, M. Xiao, M. Jahazi

Magnesium alloys have low hardness, wear, erosion and corrosion resistance. The repair of service-damaged aerospace components made of magnesium alloys is an attractive solution in terms of time and cost saving. The feasibility of applying laser beam technology to repair ZE41A-T5 magnesium alloy sand castings in the machined surface conditions was studied using a continuous wave 4 kW Nd:YAG laser system. The influence of process parameters such as laser power, cladding speed, wire feed rate and defocusing distance on the shape, size and area of single cladding beads is discussed using a process optimization software. Sound single clad beads with good geometric characteristics were obtained using strictly controlled laser process parameters. The overall results indicate that laser surface cladding using filler wire has the potential for repairing aerospace components made of cast magnesium alloys.

Jan 1, 2006

By Eugene Larochelle

The serpentine of the Eastern Townships of Quebec is more or less seamed and impregnated with chrysotile asbestos, of which we note two types: the cross-fibre and the disseminated fibre. The cross-fibre type always appears in fibres or crystals arranged parallel to one another, and disposed at right angles to the walls of the matrix serpentine. The length of fibre of these veins, which run in every conceivable direction, even crossing ?one another, varies from microscopie dimensions to three and sometimes four and even five inches. It is the principal form of asbestos found in the serpentine of Thetford Mines, Black Lake, Coleraine, and Asbestos. The disseminated-fibre type, which is the main product of the serpentine of Broughton township, in which ate located the mines at East Broughton, does not form veins, but occurs in the serpentine without any definite arrangement. There is a difference in the toughness and hardness of the rock of the two types, the Broughton serpentine being softer than that at Thetford. The disseminated-fibre section of the serpentine belt is probably more regular in its content than is the cross-fibre section. Nevertheless, it contains no 'crude,' which is the most valuable of asbestos, and the fibre is usually shorter than the cross-fibre average.

Jan 1, 1928

By C. I. Garcia, G. Zhou, W. Gao, A. J. DeArdo

The development of X-100 and X-120 linepipe steels was investigated using a series of low-carbon Mo-Nb-B steels. The laboratory steels were vacuum melted and processed using advanced thermomechanical processing (TMP) philosophies. Prior to the laboratory hot-rolling experiments, the grain coarsening temperature, the conventional T95 and T5 start-stop recrystallization temperatures and the transformation behavior of y were studied using a computer-controlled high temperature deformation MTS-458 and a Theta-IV High Speed dilatometer systems. The results from these experiments provided the guidelines for the design of the laboratory hot-rolling TMP processing experiments. The mechanical properties of the experimental steels showed yield strengths in the range 700-850 MPa and CVN impact properties of over 80 J at -20°C. The best balance of mechanical properties was obtained by using CCR+DQ+Tempering treatments. The major microstructural features responsible for the observed mechanical properties in order of importance were: a) substructural refinement associated with lower bainite, b) dislocation strengthening, c) fine recrystallized ferrite, and d) small amounts of retained austenite. Fine Nb(C,N) precipitates formed in ferrite were observed, however their contribution to the strength was minimum. Most of the Nb(C,N) precipitation took place in austenite. This precipitation was used to exert microstructural control of austenite during hot rolling. The physical metallurgy and optimum TMP to achieve the mechanical properties are detailed in this paper.

Jan 1, 2005

By M. B. Kime, A. T. Kaniki

"Grinding tests were conducted on an oxidized copper-cobalt ore using a pear-shaped ball mill. Twelve mono-sized ore fractions were prepared and wet ground batchwise. The mill was run for 0.5 to 30 min intervals. The shortest interval provided data more closely related to the breakage function (B) because less secondary breakage was hypothesized. Some selection function (S) and B parameters were determined. Remaining parameters were estimated using a population balance model simulator. To evaluate the kinetics model, an unsized ore sample was also milled. Predicted and measured particle size distributions (PSDs) agreed well, suggesting that S and B parameters can be used for continuous operation mass balances.RÉSUMÉ Des essais de broyage ont été menés sur un minerai oxydé de cuivre-cobalt à l’aide d’un broyeur à boulets piriforme. Douze fractions de minerai de dimension unique ont été préparés et broyés en voie humide en lots. Le broyeur était mis en route à des intervalles de 0,5 à 30 minutes. L’intervalle le plus court fournissait des données plus étroitement liées à la fonction d’abattage (B) car d’après l’hypothèse avancée, le besoin d’abattage secondaire était moindre. Certains paramètres de la fonction de sélection (S) et de B ont été déterminés ; les paramètres restants ont été estimés à l’aide d’un simulateur de modèle d’équilibre de population. Pour évaluer le modèle de cinétique, un échantillon de minerai non calibré a également été broyé. Les compositions granulométriques (PSD, de l’anglais particle size distributions) prévues et mesurées correspondaient bien, ce qui laisse penser que l’on peut se servir des paramètres S et B dans le cadre d’équilibrages massiques en fonctionnement continu. INTRODUCTIONSize reduction of solids is a very energy intensive and highly inefficient process. It consumes approximately 5% of the electricity produced worldwide (Rhodes, 1998), and more than 50% of the total energy used in mineral processing plants (Walkiewicz, Lindroth, & Clark, 1996). An increase in grinding efficiency can therefore result in significant reductions in operating costs. This often amounts to determining the optimal design configurations for milling an ore sample in a laboratory mill under standard conditions. Prior to optimizing the milling stage, the requirements for downstream processing in terms of particle size distribution (PSD) need to be understood because low liberation and overgrinding will lead to future problems. Once this is done, it is also important to clearly understand the breakage properties of the ore. The kinetics of size reduction in tumbling mills are often determined using two probabilistic functions: selection and breakage (Austin & Luckie, 1972). Knowledge of the selection and breakage functions also enables the prediction of the PSD for a given ore sample."

Jan 1, 2017

By L. Rodd, C. Walker, T. Koehler

"The energy content of slag represents approximately 80% of the total energy inputs to a laterite nickel electric smelting furnace. Conventional slag handling methods produce only low grade heat and the entire thermal content of the slag is wasted. A heat recovery system proven on BOF slag in the mid 1980's can be adapted to a laterite nickel rotary kiln electric furnace (RKEF) plant. Slag is granulated using a high velocity air jet inside a waste heat boiler to produce slag granules. Granules are cooled during flight via radiation to water-cooled boiler walls and by convection to the granulation air. This system has the potential to recover 80% of the total slag energy in the form of hot air and steam.Integration of the recovered slag energy into the RKEF smelter can be achieved by a number of methods, including the use of preheated air at the ore dryers, kiln or existing power plant. Energy from the slag boiler may be used to reheat boiler feed water from the power plant or to produce superheated steam and generate electricity. The heat recovery system can provide up to 25 - 30% of the total electrical requirement of each RKEF line and a reduction in CO2 emissions of 234,000 tonnes per year.The total cost of slag heat recovery, including CAPEX and OPEX, is $2.5/GJ, which is competitive with using coal when CO2 credits are $18 per tonne. With Clean Development Mechanism (CDM) carbon credits currently selling at €13 ($20 USD) per tonne CO2, there is considerable opportunity for slag producers in regions including South America, Korea, Indonesia and Africa. Increasing fuel costs and more wide-spread legislation for GHG emissions will likely create conditions in which slag heat recovery could generate a favourable return on investment."

Jan 1, 2010

By The Staff

This is in direct contradiction to the generally accepted philosophy of tube-mill grinding, which is based upon an enormous amount of experiment carried on in different parts of the world. Personally, I have no faith in the reliability of these conclusions of the authors. (Incidentally, the two circuits compared consist of six mills each of which the change in the hook-up is only in the last three mills-in one case, these three mills are in closed circuit and in the other, open or series circuit. Hence the last three mills are alone responsible for the alleged improvement, which means that the improvement in these three mills amounts to at least 18.8 per cent). The value of these figures depends upon the reliability of the work, of the measurements and the calculations of the authors. As very little information is contained in this Addendum concerning the methods of the work and the details of the measurements, it is necessary, in order to form an estimate of this reliability, to study carefully the previous paper published in the July, 1940, BULLETIN(3). Referring to the original paper, the present paper has this to say (bottom of page 379): "Here it may be remarked that we have made more money for Lake Shore digging into and forming the report than in obtaining the figures and data, and so far have never gone back to work on it without a resulting Lake Shore profit". Let me state that I, so far, have never gone back to work on it without finding more discrepancies and inconsistencies and illogical reasoning. In my first contribution to the discussion of the first paper, which discussion was published on page 355 and following, in the July, 1941, BULLETIN, I pointed out discrepancies and inconsistencies and illogical reasoning.

Jan 1, 1942

By M. Nagamori, A. J. Plumpton

"Commercial HCl-leaching of magnesite and serpentine yields highly concentrated aqueous solutions containing 25 mass % to 33 mass % MgCl2. The partial molar enthalpies and heat capacities, the ionic activities of Mg2+ and Cl–, and the Raoultian activity of H2O have been assessed for the concentrated MgCl2-H2O solutions at temperatures of 348 to 373 K. These thermodynamic data are used to calculate the pH of aqueous MgCl2 solutions saturated with a Mg-bearing mineral such as magnesite, serpentine, brucite, forsterite, enstatite or talc. On the basis of these thermodynamic data, technico-economic aspects are discussed as to neutralization with pulverized MgCO3, water evaporation from the MgCl2 solutions, and ore composition including such minor constituents as CaCO3, FeCO3 and Fe3O4. IntroductionA major magnesium electrolytic reduction plant operates in Quebec, where another will begin its production in the year 2000. One uses imported magnesite ore as raw material, while the other will utilize local asbestos tailings (serpentine). Both processes produce a concentrated salt solution of 25 mass % to 33 mass % MgCl2 by leaching the ore with concentrated hydrochloric acid. Thus, the two processes differ mainly in the HCl-leach and related operations. After the HCl-leach of the ore, the serpentine process yields about 25 times more wet cake to filter and wash than the magnesite counterpart. A comparative cost-engineering study with respect to slurry filtration and cake washing has been published elsewhere (Blackburn and Nagamori, 1994). By contrast, the present study considers the thermodynamics and technicoeconomics of the HCl-leach itself for both ores."

Jan 1, 1999

By G. M. Hughes, R. W. Dunn

"AbstractCurrently installed an analogue instrumentation devices at Sherritt 's Ruttan Concentrator control. and/ or measure mill tonnages, grind, pH, density , some reagent and slurry flows, and cell levels. On-stream analysis is used to assay the main process streams. The history of development of process control is reviewed from startup to the present stage of selection of a process control computer. A pragmatic approach has been taken to process control to ensure compatibility with the needs and resources of Ruttan. Emphasis is made of the need to have the mill performing well from a mechanical and instrumentation point of view and to have opera tor acceptance of the computer through training. Plans for the computer phase to achieve these objectives are outlined.IntroductionTHE COPPER-ZINC OREBODY at Ruttan Lake was discovered by Sherritt exploration personnel in 1969 and by mid-1973 a 10,000-tpd mine and concentrator were in operation. After a typical startup period , the major mechanical problems in the crusher and concentrator have been resolved. Metallurgical performance is now up to standards forecast in the feasibility study.The cost of the original instrumentation installations, including an on- stream analyzer, was about one million dollars or 4% of the cost of the milling complex. Although there was no intention of using a process control computer until the plant was operating smoothly, it was understood that all instrumentation was compatible with .a computer, but this did not prove to be correct. This paper cover s the development of the instrumentation loops to date and the control strategies that will eventually be implemented through a process control computer."

Jan 1, 1977

By George Kellock

Introductory The Alberta Provincial Government has contemplated a revision of the Mines Act for some time past, and it is understood that a definite decision has now been made to do this at the next session of the Legislature. The Operators' and Miners' organizations of the Province have been asked, or at least have been given the opportunity, to submit their views and ideas relative to the proposed changes. The operators have already drafted out a number of changes which they feel would improve the Act from the standpoint of safety and practicability, and this paper has been prepared so that the general membership of the Rocky Mountain Branch of the Institute, which is composed largely of the operating and certificated officials of the mines, might have an opportunity to discuss, criticize, and improve upon the suggested changes which the operators are putting forward.

Jan 1, 1929

By C. H. Hopper

DIAMOND drills have played an important part in the development of mines for many years. Recently. they have also entered the production field arid the use of diamond drills m the primary breaking of ores has become a big branch of the industry. The writer has estimated roughly that the total diamond drilling in Canada during 1942 was 5,625,000 feet, of which 2,250,000 feet, or 40 per cent, was for blast-holes. This accounts for 6,750,000 tons of ore broken, using the conservative factor of 3 tons per foot of hole. Many consider that the use of diamond drills for blast-holes is the most important advance in mine practice of the past decade, and the industry owes a great deal to the staff of Noranda Mines, Limited, for the pioneering they have done in the development of long-hole mining methods and for publishing their results. A great many mines have followed Noranda's lead. At the Waite-Amulet, Aldermac, Flin Flon, Canadian Malartic, Hoyle, and Matachewan Consolidated mines, most of the ore is broken by long-hole blasting. While the mines were developing new methods, the diamond-drill industry was developing mechanically-set bits and better machines. Through the effective use o smaller, cheaper diamonds, as well as more efficient setting, bit costs per foot are only one-half what they were ten years ago. Few people realize that a diamond bit is relatively inexpensive. The common EXT coring bit, for example, contains some 200 small diamonds, weighing altogether about 2.70 carats which, at $3.40 per carat, cost $9.20. After use, the equivalent of about 100 of these diamonds may be recovered. Therefore the true cost of the bit is only $7.00, made up of $4.60, the cost of the diamonds lost, $2.00 for setting, and $0.40 tax. The trend in machines has been toward specialization for the different classes of rock in blast-hole work. Light, high-speed machines have been developed for soft ores and higher powered machines for hard ores.

Jan 1, 1943

By Kurt D. Mitchell

"This paper discusses general application for A C variable frequency drives in the mining industry. A review of induction motors characteristics, adjustable frequency controller fundamentals, and three commonly used controllers is presented. General application guidelines for the three different types of controllers; variable voltage input , current source input and pulse width modulated are then reviewed in detail, and an example of the economic benefit of this technology is discussed. IntroductionSoon after static DC variable speed drives were well established in industry, a need for static AC variable speed drives was seen. The first technical papers describing possible systems appeared in the mid-1960s, with commercially available units arriving in the early 1970s. Without exception, static AC drives are substantially more complex than their DC counterparts, but they have some very desirable properties. As compared to DC motors, AC motors are less costly, physically smaller, more reliable, require less maintenance , easily sealed, have good load regulation, are able to run at higher operating voltages, and have little danger of over-speed runaway . These properties are particularly desirable in explosion-proof, submersible or difficult accessibility applications.Variable speed AC drives are now a proven technology. available in packages from Sub-horsepower to hundreds of horsepower, from 115VAC to 4160 VAC. This paper covers the principles of operation of three common types of controllers, application criteria, motor consideration and finally an example of how an AC variable speed drive can pay for itself in terms of energy savings."

Jan 1, 1986

By J. Pontt

Gearless mill drives (GMD) offer high performance for torque and speed control for grinding mills and have been applied successfully in modern concentrators for wet grinding with mill diameters from 34 to 40-feet. It is considered a mature technology. However, recently, some large GMD?s have presented unexpected failures in stator and rotor subsystems. The phenomena involved in such failures has shown a complex nature and surprised users and manufacturers. The manifestation of such failures has been observed as mechanical damages to certain components of ring motors. This paper presents a discussion on the electromagnetic forces that can generate stresses in the electrical ring motor that can produce failures and outages. Guidelines for further research and contributions to improved reliability of GMD?s are proposed.

Jan 1, 2012

By E. Chiyangwa, L. Schoeman

The commercially successful electrowinning and refining of metals typically requires the optimization of the electrolyte composition and operating parameters to produce high quality compact electroplated metal. The prediction of the effect of the electrolyte composition on the structure and morphology of the plated metal remains a challenge. Initial work on the use of polarization measurements to predict and control plating behaviour in electrowinning plants involved potentiodynamic polarization but proved unsatisfactory as accurate and repeatable predictions could not be achieved. The aim of the present work was to develop a reliable galvanodynamic technique specifically applicable to the plating of zinc from sulfate electrolytes with which plant operation may be controlled and optimized. Initial results indicated that plating and nucleation potentials could be measured accurately and repeatably and that the relationship between the two could be used as a predictive tool for the effect of electrolyte composition on the quality of zinc electrodeposits.

Jan 1, 2014

By G. A. Vissac

METHODS of coal preparation have been greatly developed and improved during the past few years. Under the pressing competition from substitutes that have been displacing coal as a source of heat or power, the coal industry has been able, in many cases, not only to hold its own but to regain much of the lost ground, by offering better products of a higher value. The purpose of this paper is to present, in a brief and simple form, the principles of the latest methods and machinery used in coal preparation, in order to enable the coal operator t0 select methods and equipment capable of solving his own problems in the most efficient and economical way. The paper will deal, in the main, .with coal cleaning. It must be emphasized, however, that a complete coal preparation study covers many other operations, such as handling, screening, de-dusting, dust-proofing, and ash-conditioning. Handling Coal From the producing face to the railway car, coal must be handled with great care, t0 prevent degradation, because the coarser sizes are not only easier to clean than fines but, for our markets, they are often the more valuable. Generally speaking, such care is less important or is unnecessary in the Old Country, where conditions are different. The best way to minimize breakage is to avoid gravity methods in coal transportation. All chutes in a preparation plant should be shaken mechanically, and cleaning processes requiring large surge bins must be avoided. De-Dusting De-dusting of coal is accomplished by the use of vibrating screens, fans, or classifiers, or by a combination of these. Fines below 1/32-in. (or coarser than this, with some coals) can very seldom be cleaned efficiently. Common practice is to discard them immediately, if the moisture content of the coal allows this to be done. Otherwise, they are liable to give unnecessary trouble, either in the form of dust or sludge, which are difficult to collect or to settle. Flotation is the only process which will effectively clean fines.

Jan 1, 1937

By D. Auerswald, M. Kotze, V. Yahorava, T. Udayar

Uranium can be recovered from lower grade uranium ores (<800 mg/kg U3O8), leach residues, and waste dumps cost-effectively via resin-in-pulp (RIP). Using this technology, no solid/liquid separation or washing of the leach residues are required. Furthermore, the uranium recovery can be higher than with conventional methods. RIP technologies have, however, been perceived negatively due to concerns around potential resin fouling and losses. This paper highlights the advancements made in RIP and discusses a number of potential applications where the technology could deliver economic and consequential environmental benefits by reducing the uranium levels in the waste.

Jan 1, 2014

By M. Tardif, F. L. -Lavoie, M. Ruel

"In mineral processing, it is often very difficult to reliably measure several key operation variables. The harsh environment and high temperature encountered in pyrometallurgy processes lead to some difficulties when selecting the instruments, valves and actuators. If an important variable cannot be measured or manipulated adequately, controlling it can really become a big challenge. Sometimes, it is simply impossible to find the perfect equipment for the task. To help overcome these difficulties, a different approach is required. This approach will not correct the inherent problems related to the instruments and valves, but will cope with these problems. This article will demonstrate how modern process control techniques can be used to solve complex problems while remaining easy to implement. In this article we will described how soft sensors and multivariable fuzzy logic control were implemented at Koniambo Nickel to stabilize the furnace feed and allow for safe and reliable operation of an 80 MW DC arc furnace.INTRODUCTION Process Overview The process plant at Koniambo Nickel SAS is located in the North Province of New Caledonia, 310 km north of Noumea. The nickel-bearing ore is mined in the nearby Koniambo massif. After being screened and crushed, the ore is transported to the processing plant using a 12 km conveyor. After stacking in two blending piles, the ore, containing 2.3% nickel, is fed to the processing plant where it will go through the NST process (Nickel Smelting Technology) before being sent to refining and shotting. This article will focus on the improvement to control of the NST processes. The first steps of this process consist of milling the ore and removing all moisture through calcining (Figure 1)."

Jan 1, 2017