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By M. Tadie, J. Wiese, K. Corin

The use of potential control in the flotation of ores has been applied in a variety of operations and presents an opportunity for improvement of selectivity and recovery of valuable minerals. Although it is possible to vary the redox potential (Eh) using chemical additives such as sodium hypochlorite or hydrogen peroxide this is more commonly done by varying the pH and dissolved oxygen (DO) concentration. The present study involves an investigation into the effect of varying dissolved oxygen concentration, ionic strength (IS) and pH on the flotation response with the aim of application to a South African lead-zinc ore. In all cases the Eh is measured as a function of the different DO, IS and pH values. The main objective was to achieve selective flotation of galena from sphalerite. The first part of the work was micro-flotation tests conducted on single minerals with galena used as the basis for effect of the factors studied on redox potential and ultimately recovery. The DO was varied by alternating between the use of air and nitrogen as the gas source to the micro-flotation cell. PH was varied between pH 9.2 and pH 11.8 using sodium hydroxide. In the first part of this study a factorial design approach was used to determine the interactive effects of the variables tested, viz. DO, ionic strength and pH, on the Eh and on the recovery. Redox potential was measured using a combination electrode made up of platinum wire and Ag/AgCl reference combination. Recoveries indicated that pH had the most significant effect on recovery and Eh. The influence of redox potential on recovery was found to be of relevance to the condition of high dissolved oxygen concentration and less so at low dissolved oxygen concentrations. It was also noted that that the combined interaction between ionic strength and dissolved oxygen concentration had a positive effect on recoveries, however this was not so with Eh. The chemistry of the ions in solution was observed to play a dominant role on the recovery due to changes in solubility arising to pH modification. The longer term objective of this work is to determine the optimal Eh conditions for the separation of galena from sphalerite.

Jan 1, 2016

By Barry James

Energy, like labour and materials, is one of the basic production inputs in the industrial minerals industry. This paper discusses the significance of the changing energy situation in Canada as it affects the industry. It is apparent that the importance of energy as a management concern has increased considerably since 1973. The importance placed on energy management today will undoubtedly be an important factor in determining company and industry sector strength and profitability tomorrow.

Jan 1, 1978

By M. Courtin, D. Berthelot, M. Haggis, D. McClarty, R. Payne

Over forty years of uranium mining in the Elliot Lake region of Ontario (1956–1996) has resulted in the production of over 300 million pounds of uranium. With the completion of mining activity, Rio Algom Limited and Denison Mines Limited are utilizing progressive environmental technologies and management systems to reduce and manage the environmental risks associated with the 150 million tonnes of potentially acid-generating tailings in nine regional waste management areas. Water covers designed to reduce oxygen entry and, thereby, significantly inhibit acid generation, have been applied at six of the sites with the Quirke site serving as a demonstration site for the Mine Environmental Neutral Drainage program. All five of Rio Algom Limited’s effluent treatment plants are monitored and controlled from a central control station utilizing a Supervisory Control and Data Acquisition (SCADA) system based on “Fix Dmacs” technology. Scheduling, auditing and reporting of plant operating and environmental monitoring programs for the entire watershed are controlled utilizing the Regional Environmental Information Management System (REIMS). Proper application of these technologies and management systems facilitates delivery of cost-effective environmental monitoring, care and maintenance programs at these sites and provides tools to demonstrate compliance with all environmental performance criteria.

Jan 1, 1999

By Peter Moon

THE mineral industry of Canada relies heavily upon the talent of its technical men. It is vital to the well-being of the industry that its supply of young, trained men be adequate. At the present time, the industry is acquiring only 200 new graduates a year. The shrinking supply is far below present and future requirements. Other industries and research organizations are competing for engineers and scientists. Dr. J. B. Mawdsley (1), Past-President of the Canadian Institute of Mining and Metallurgy, has recently outlined a program designed to attack the problem. Dr. J'. C. Sproule (2), another former President of the Institute, has stated that: "The need for selection of trainee material is commonly recognized, but little is done about it." The following paper contains a short discussion of occupational interests, and outlines research, using psychological knowledge and measuring techniques, aimed at the identification of desirable recruits for the mineral industry.

Jan 1, 1963

By G. Morin, F. Chiesa, B. Tougas, B. Duchesne, Jocelyn Baril, N. Giguère

"An aluminum A356 compressor impeller was sand cast using the Low Pressure technique. The casting was limited in size (170 mm in diameter, 1.2 kg in weight) and very intricate in shape thus making 3D mold printing particularly favorable; indeed, producing this part by the traditional pattern-core box route would involve mounting 12 cores inside the mold while stringent dimensional tolerances are required as the impeller blades are only 2 mm thick. Consequently the molds were produce on the X-One MFlex printer of Quebec Metallurgy Center - CMQ. A dozen castings were produced with different casting temperatures and filling times so that it was possible to assess under which conditions complete filling of the mold cavity would be achieved. Filling and solidification modeling allowed predicting misruns and metallurgical properties inside the A356 (AlSi7Mg04) casting.INTRODUCTION Recent advancements in additive manufacturing enable foundries to produce molds without the tooling (pattern and core boxes) necessary when conventional technology is used (Eyad, 2016). This is particularly advantageous when dealing with intricate shapes and/or when a limited number of parts must be produced within a few days rather than in 5 weeks. An additional advantage is gained when producing prototypes (Johnson, 2016) as changes are much less costly and time consuming when made on a numerical 3D drawing rather than on patterns and core boxes. 3D printing is normally economical for a small number of parts; however, if the part is not too big and very intricate in shape such as the part that will be studied in the present work, 3D printing can be economical even for an important number of castings to be produced. On the other hand, low pressure casting is a high integrity casting process in which the mold cavity is filled from the bottom via a transfer tube in which the liquid aluminum rises under the pressure applied at the surface of the melt as illustrated in Figure 1. The filling can thus be precisely controlled, eliminating the turbulence created when the mold is filled from the top (gravity casting). Also, the pressure applied on the melt during solidification results in excellent feeding of the casting when conditions of directional solidification are met. In the present work, the compressor impeller shown in Figure 2 will be sand cast by low pressure."

Jan 1, 2018

By E. Lee Cameron

Summary Records of the past show that the first mineral production in what is now the Province of Manitoba consisted of salt, obtained about the year 1800 by the evaporation of brine. Also at an early time in our history, the Ordovician limestone at St. Andrews Locks, East Selkirk, and other localities was quarried for use as building scone in the construction of forts and fur trading posts. Both salt and building stone are still produced in Manitoba, although not from the original sources. In addition, there is now a substantial production of a variety of other industrial minerals and their products such as lime, crushed stone, gypsum, peat moss, and bentonite. The annual dollar value of production of the industrial mineral industry in Manitoba is today greater than at any time in our past and is derived from a greater variety of products. At the present time, exclusive of the various gravel pits operated by the Provincial Department of Public Works, twenty companies operating thirty-four separate pits, quarries, or mines are producing industrial mineral raw materials in Manitoba. This paper attempts to outline the development of the industry from its start about 1800 to the present, giving general information on the various materials produced. Some suggestions regarding the possibilities of establishing new industries based on other raw materials are given at the end of the paper.

Jan 1, 1949

By Waldemar W. Koczkodaj, William O. MacKasey

A consistency-driven pairwise comparisons method for mineral potential assessment is presented, using a simpli?ed case of volcanic-associated massive sul?de type deposits as an example. Geological, geochemical, and geophysical criteria are considered on two levels: local and regional. The local geological criteria are subdivided into stratigraphy, lithology, alteration and/or mineralization, and structure. The concept of geomerit index and a procedure for computing this index are introduced. The method of consistency-driven pairwise comparisons can be combined with other quantitative and qualitative assessment methods, enhancing them by incorporation of non-measurable geological criteria (e.g., stratigraphy or lithology) and by computation of weights. The consistency-driven approach allows experts to re?ne at-times subjective judgments concerning exploration and land-use planning, and contributes to the improvement of mineral-potential assessments.

Jan 1, 1997

By Waldemar W. Koczkodaj, William O. MacKasey

Abstract - A consistency-driven pairwise comparisons method for mineral potential assessment is presented, using a simplified case of volcanic-associated massive sulfide type deposits as an example. Geological, geochemical, and geophysical criteria are considered on two levels: local and regional. The local geological criteria are subdivided into stratigraphy, lithology, alteration and/or mineralization, and structure. The concept of geomerit index and a procedure for computing this index are introduced. The method of consistency-driven pairwise comparisons can be combined with other quantitative and qualitative assessment methods, enhancing them by incorporation of nonmeasurable geological criteria (e.g., stratigraphy or lithology) and by computation of weights. The consistency-driven approach allows experts to refine at-times subjective judgments concerning exploration and land-use planning, and contributes to the improvement of mineral-potential assessments.

Jan 1, 1997

By S. Gößling-Reisemann

Most copper ores contain valuable co-products such as molybdenum, gold, silver, nickel, etc. Sulphuric acid and steam are valuable by-products, which are generated dur¬ing copper production. The environmental impacts from mining and refining therefore need to be shared between these by-products and co-products, an issue in Life Cycle As¬sessment (LCA) referred to as allocation. There are different, recognised methodologies for doing so: burdens can be allocated based on the market values of these commodities, they can be allocated by mass, volume, molar amount, functionality, or other physical, technical or economic factors. All of these methodologies have their respective merits and restrictions, and the choice is usually case specific. Nevertheless, the choice between alternative methodologies can have dramatic effects on the LCA results. Recycling in LCA has to be handled in a similar way, as it essentially constitutes a special case of co¬production. The existing standards (ISO 14040 ff.) allow different methods for imple¬menting recycling and allocation into metal LCAs (open loop, closed loop, value cor-rected substitution, etc.), which are still a subject of discussion in the scientific community. However, the methodology used can significantly influence the ecological profile of copper and copper products. We will present an overview of the different methodologies available for including recycling and allocation and give an analysis of how the meth¬odological choice affects the final LCA results. This work will be followed up by quantitative case studies.

Jan 1, 2007

By M. Kosugi, Y. Kon, M. Kawata, J. V. Satur, K. Mitsuhashi, C. Tokoro, K. Horiuchi, R. Kawarabuki, B. Calabia

"Liberation of copper minerals is important in ensuring high flotation efficiency in copper sulfide flotation. The high pressure grinding roll (HPGR), microwave (MW), and electric disintegration (ED) are known to feature enhanced liberation over conventional comminution machines such as jaw crushers and ball mills by producing internal stresses on minerals or mineral grain boundaries through high compressive forces, thermal expansion of minerals, and pulsed high voltage discharges, respectively. In this study, each of these methods was applied before ball mill grinding to investigate its effect on enhancing the liberation of copper minerals in a low grade and fine-grained copper ore. The copper minerals observed in the tested ore sample are bornite, chalcocite, and chalcopyrite, and their grain sizes range from 10 to over 100 µm. Calcite, quartz, and feldsparare confirmed as gangue minerals. The liberation of the copper minerals by the different methods was analyzed using the mineral liberation analyzer (MLA) and compared. The result showed that the HPGR crushing was the most effective for enhancing copper mineral liberation. HPGR bench-scale test was then conducted on the copper ore and flotation was applied on a HPGR-treated sample to confirm the improvement in the flotation performance by applying HPGR.INTRODUCTIONIn order to recover copper minerals by flotation, copper ore is usually ground by ball milling to liberate the copper minerals from gangue minerals. In the case that the fine size copper minerals are targeted, grinding of the copper ore to a finer size is necessary to increase the copper recovery. However, finer size grinding by ball mill increases energy consumption significantly, which might deteriorate the economies of the mineral processing operation. HPGR, MW, and ED have been recently the focus of researchers as new techniques for enhancing the mineral liberation in mineral processing (Tavares, 2004; Kingman, 1998; Wang, 2010).HPGR crushing is considered to generate micro cracks along mineral boundary when rocks pass between two rolls by applying high compressive force. In the MW treatment, micro cracks are reported to be generated at crystal boundaries by differential thermal expansion of crystals attached to each other. In the ED treatment, micro cracks are known to be produced by plasma current flowing along mineral grain boundaries. These treatments are expected to increase mineral liberation (Fujita, 2001),improve flotation performance(Michaelis, 2005), and reduce ball mill work index(Kaya, 2010)."

Jan 1, 2017

By Fathi Habashi, Ahmet Deniz Bas

"The mechanism of leaching of semiconducting minerals such as PbS, ZnS, UO2, etc., has been the subject of intensive speculation by hydrometallurgy researchers in the early 1950s who assumed the formation of intermediate surface complexes that could be neither separated nor identified by physicochemical techniques. The electrochemical theory of leaching introduced in the late 1960s resolved this problem by comparing the leaching process to a corrosion phenomenon similar to the corrosion of metals. Few years later, experimental evidence showed that anodic and cathodic zones are formed on the dissolving mineral although no electric current is imposed on the mineral during dissolution. A discussion of these findings is outlined.INTRODUCTIONIn the early 1950s researchers realized that kinetic studies for leaching ores are as important as thermodynamic calculations. It was also during this period that the concept of species adsorption on mineral surfaces has dominated the interpretation of the mechanisms of most reactions. This may have been due to the fact that many researchers of this period came from the mineral dressing sector and were influenced by flotation theories. However, when the knowledge of lattice defects and the semiconductivity of minerals became known and their importance in extractive metallurgy was realized, there was a need to explain the leaching reactions in light of these modern theories (Habashi, 1969, 1970). Semiconducting minerals of importance in metallurgy are two categories: the sulfides such as those of copper, lead, zinc, and the oxides such as those of uranium."

Jan 1, 2016

By T. Rigg, J. N. Stone

"The process described has been developed to utilize low-grade scrap -turnings, borings, tin cans and other types of ferrons scrap which currently has been of limited or no use in conventional steelmaking processes. If scrap of this type can be converted into high-purity iron by chemical means then there is a potential saving of several million tons of metal annually in North America.The process is chemically quite simple and consists of dissolving ferrons scrap in hydrochloric acid, followed by evaporation and crystallization of the resultant solution to yield ferrons chloride crystal.s. These crystals are dries, briquetted and converted to non sponge by reduction in hot hydrogen. The HCl produced from the reduction step. is absorbed in water and the hydrochloric acid so produced is returned to the dissolver circuit. The hydrogen produced from the initial dissolution of the scrap is used to reduce the ferrons chloride. Purity is maintained by bleeding off impure chloride solutions from the evaporator-crystallizer circuit, and converting these chlorides to oxides and HCI in a high-temperature spray roaster. The HCl produced in the roaster is absorbed in water and the hydrochloric acid returned to the dissolver."

Jan 1, 1970

By P. Radziszewski

Industrial practice in mineral processing shows that an important problem in understanding and monitoring in-mill parameters is due to the lack of fundamental knowledge and appropriate sensors. With the development and growing use of DEM charge motion simulators for mill optimisation and design, it is possible to describe the fundamentals of grinding mill behaviour, in improving the understanding of internal grinding mill dynamics and in developing solutions to industrial practice. The main challenge to bringing this DEM technology to the mill operator however was the need for substantial computing power and time. However, what about a simplified DEM charge motion model running in real-time? What about the use of sensor technologies to correct any possible drift in simulator prediction? Could such a technological system be used to predict mill performance and eventually be used for mill control and optimisation? Some of these questions are answered with the development of an "on-line" DEM charge motion simulator package (SAGTools?) along with that of a number of sensor technologies (liner wear, acoustic, instrumented ball) that can contribute to simulator precision. With the objective of bringing this modelling and sensor technology into the concentrator control room to assist operators, this paper aims to describe the main elements of this emerging and developing technology and discuss how it can lead to online mill performance prediction and eventual control.

Jan 1, 2007

By J. Paraszczak

ABSTRACT Diesel-powered loaders are a pillar of modern underground metal mining. As these mines are getting deeper and hotter and the emission regulations stricter, ventilation costs are soaring, affecting production cost. Also, the cost of diesel fuel is expected to rise. These may make the use of diesel engines more problematic. Electric load-haul-dump machines (LHDs) are an interesting alternative. This paper compares features and performance of diesel and electric, cable-powered LHDs. It overviews equipment offerings, and compares, analyzes and discusses technical parameters, operational problems and cost issues. The paper gives some conclusions about electric LHD applicability and performance, indicates possible applications, and suggests further research work.

Jan 1, 2013

By R. Laucournet, E. Billy, M. Joulié

Today Li-ion batteries are considered as one of the most attractive available energy storage solutions. However in order to overcome environmental, legislative and economic issues, the management of used batteries has to be considered and mainly the recycling. The present paper deals with the recycling of used Li-ion batteries and the recovery of high value metals from active materials of electrodes. Lithium nickel cobalt aluminum oxide (NCA) and lithium manganese nickel magnesium oxide (LMNM) cathodes, which contain most of valuable elements typically used in the composition of active materials for Li-ion batteries are investigated by a hydrometallurgy route. The process is divided into two steps: the materials leaching and the elements recovery by a selective chemical separation. Some experimental parameters (acid nature, concentration, time and temperature) are studied to determine the most efficient conditions of dissolution. Then, the valuable elements such as nickel, cobalt and manganese are selectively recovered with a high efficiency close to 100 % and with a high purity by precipitation. By this study, an adaptable hydrometallurgy process can be defined according to the composition of Li-ion batteries to recycle.

Jan 1, 2014

By L. Veleva, Garcia. A., G. Perez

Aluminum is a metal used for the transmission of electricity of high voltage, in the construction industry and other areas. In atmospheric conditions aluminum forms an oxide layer (Alz03'H20) as a result of its corrosion, entering the passive state. The oxide layer can be destroyed by the presence of ions (Cr, SOx-n) developing localized (non uniform) corrosion attack by pitting, difficult for evaluation. The concepts of fractals and self-similarity were used in this study for the characterization of the development of localized corrosion. Images obtained with a scanning electron microscope (SEM) of samples of electrolytic aluminum wire that have been exposed during one year in ruralurban and marine-coastal environments of the humid tropical climate of Mexico, have been processed. The development of pitting has been studied as a function of time, making a statistics of the frequency of appearance of pits versus the area occupied by them. The data show that the distribution of the pits follows a power law. Therefore, the concept of self-similarity can be applied for the study of the phenomenon of localized corrosion, describing their development with time.

Jan 1, 2006

By Nirmal Weerasekara

Mill liners serve the dual purpose of protecting the shell from wear and transferring the rotary motion of the mill to an effective grinding action. As the liners wear, the efficiency of energy transfer changes, so there is balance between liner profile for wear and for milling efficiency. A tool that can simultaneously predict the evolution of the liner profile and the associated change in milling efficiency should prove most useful in optimal liner design. This paper presents such an approach, based on measured 3D liner profile data informing 3D DEM simulations of charge motion and liner wear modelling.

Jan 1, 2012

By J. Lui

Inco Copper Cliff Smelter commissioned two new Inco flash furnaces in 1991/1993 as part of its S02 abatement program. Each flash furnace is equipped with a fluid bed dryer. The ~ 12 wt% water content in the concentrate filter cake, flux, reverts and sludge is removed in the fluid bed dryer. The dry solids are discharged from the dryer together with exhaust gases into the baghouses where they are separated. The dry solids are transferred to four storage bins. In September 2003, for the first time since startup in 1991/1993, a large amount of elemental sulfur accumulation was discovered on the walls, roofs and floors of the outlet side of the baghouse chambers. Several baghouse fires were experienced during cleaning and conducting maintenance work in the elemental sulfur contaminated baghouses. Laboratory scale test work at the Inco research lab was conducted to understand the mechanism. A plant solution to minimize elemental sulfur formation was implemented with success. This paper summarizes the efforts to understand and minimize elemental sulfur formation in the baghouse chambers.

Jan 1, 2007

By J. Paturaud, A. G. Villemiane, J. Y. Buffiere, D. Fabregue, M. Perrier

In this work, a detailed characterization of the cyclic damage mechanisms on duty in car heat exchangers has been carried out in order to improve their reliability. The material which consists in very thin (<0.3 mm thick) sheets formed of 3 co-rolled aluminum alloys (4045 /3916/ 4045) has been brazed in order to obtain metallurgical and surface conditions representative of those of the real components. Fatigue tests at constant stress amplitude have been performed at room temperature and 120°C in order i) to characterize the cyclic resistance of the studied materials and ii) to study the effect of temperature on the fatigue damage mechanism. The mechanisms leading to failure have been identified from post mortem fractographic analysis. The Wohler curves obtained show that, contrary to common structural Al alloys, this type of thin sheet brazed multi material can be cycled for several hundred thousand cycles at very high stress level (> ~ 80 % of the tensile strength). This behaviour is analysed with respect to the microstructure resulting from the brazing process and the low number of grains present in the sample thickness (around 5 grains).

Jan 1, 2015

By J. Zollinger, J. R. Kennedy, J. H. Park, D. Daloz

"In order to improve the properties of cast Ti-Al alloys to replace Ni-based superalloys past the low pressure stages of aircraft engines investigations into inoculation for grain refinement were carried out. Previous work showed isomorphic self-inoculation using Ti-Al-Nb particles was effective for grain refinement, however the relatively fast diffusion of Nb in Ti-Al make it difficult to observe the mechanism of nucleation. An alternative alloy was developed in the Ti-Ta system for isomorphic self-inoculation, maximizing the Ta content to improve the particles survivability in the melt. The powder processing produced comparatively small inoculant particles which dissolved, however larger particles were seen to survive solidification. The density difference between the inoculant particles and melt resulted in an inhomogeneous mixing of the particles and the melt with larger particles found near the outer edges of the ingots. Variations on particle size and interaction time between the inoculants and the melt resulted in the Ti-Ta inoculant reducing the as-cast equiaxed grain size by a factor of two compared to non-inoculated samples as well as increasing the equiaxed fraction in the ingot.INTRODUCTION Lightweight metals are of particular interest in aerospace applications. The hot sections of turbines are dominated by blades made of nickel based superalloys. Recently the GEnx turbine introduced TiAl blades in the last low pressure stage of the turbine to reduce weight and improve fuel efficiency (Kim & Dimiduk, 1991). In order to carry these benefits deeper into the turbine the high temperature (>800oC) properties of the alloys must be improved. Current grain refinement methods to improve properties rely on boron additions which may not be applicable for all blades as brittle precipitates may be formed during processing (McCullough, Levi, Mehrabian, & Hyman, 1991). A novel grain refinement process was previously introduced called “isomorphic self-inoculation” using Ti-Al-Nb particles to successfully grain refine TiAl (Kennedy, Zollinger, Bouzy, & Daloz, 2016). In order to better understand the mechanism of this process an investigation was carried out using the same process but with a Ti-Ta alloy which is more stable in the TiAl melt than the Ti-Al-Nb."

Jan 1, 2017