Search Documents

By W. Petruk

"D. Doyle How large is the beam to which you referred? Are we considering Watts, Griffis the probe of a 1 micron sized particle?& McOuatReply Yes. The beam would be about 1 micron. We could enlarge or reduce it depending on the current in-put.D. Doyle Then chemically bound material we might not see. If you are restricted to 1 micron then you would not be able to separate things smaller than this. Is this not so?Reply We won't be able to analyse it but we will see it as the scanning electron microscope has a resolution down to about 0.1 microns. We should be able to get the general composition of such a grain plus its surrounding grains. We feel we can then make a reasonable estimate if it were as small as 0.1 microns. An accurate analysis would be achieved with grains of 3 and 4 microns.D. Doyle Would this have an application in the hydrocarbon field?Reply The lowest atomic number would be sodium. We wouldn't be able to go below that atomic number. Anything with sodiumor a larger atomic number would enable us to analyse the carbon.M. Fairwether Do you have any policy relating to priorities. For instance areCominco companies going to be limited in the amout of samples permitted to give everyone a chance because quite frankly our company, and I'm sure all base metals companies can hardly wait for the installation of this equipment. I can forsee two years back-log of work in the first month.Reply Quite frankly, I haven't looked at this. At the present time the work is under the START program but I suppose we will have to look at possible changes. Anything under the START program has first line priority.B. Thorndycraft Will the briquetting of samples be automated as well? Pinson MiningReply No, not at this point. Our polish section laboratory is first-class and can turn out 18 polish sections a day which is more thar we can handle.B. Thorndycraft With the capability of this machine to operate in a hands-off manner perhaps it could start to look for the 5 micron gold particle in tailings?Reply I have such a program using a wave-length spectrometer rather than the energy dispersive. The wave-length spectometer is about 10 times as sensitive and would scan the section much faster. A one inch diameter polished section would be scanned in about 7 hours for anything 1 micron or larger."

Jan 1, 1984

By Ron Tessier, Claude Bazin, Robert Grant, Mike Cooper

"Grinding simulators are now widely available to assist in the optimization of industrial circuits. They provide circuit operating conditions or flowsheet designs that yield a given product size distribution. However, they do not provide information of the impact of a change of product size distribution on the subsequent flotation or leaching stages. This paper presents a method to predict grade and recovery indices for a flotation plant as a function of the flotation feed size distribution. The application of the method to various size distributions allows the determination of the optimal fineness of grind. A case study for a CuPb rougher circuit of a New Brunswick complex sulphide processing plant is presented to illustrate the method.IntroductionIs the grinding circuit product fineness optimum for the subsequent separation steps? This is a question that is certainly very difficult, but critical, to answer. Laboratory and pilot plant testworks can provide clues as to whether grind should be finer or coarser. For a full scale operation there is no other way than trying to change the setup of the grinding circuit and verify the effect on flotation. True effects can, however, be masked by the numerous and unexpected disturbances inherent to grinding and flotation circuit operations. A good preliminary investigation requires a noise free environment to elaborate possible solutions for the question.Plant simulators provide this noise free environment. However, despite grinding and flotation simulators having evolved significantly for the last 20 years, very little is available on the integration of both simulators to analyze the effect of fineness of grind on metallurgical performances. For instance, a grinding circuit simulator may help to find the tuning of a grinding circuit that will yield the desired fineness of grind, but does not inform on the effect the new product size distribution will have on the separation stages. Linking grinding and flotation would require a flotation plant simulator with the rate and infinite recovery parameters for each mineral in each size interval considered. This approach is seldom used because of the tedious work required to estimate the model parameters. Recently Leroux(1992) proposed a method to predict mineral liberation from grinding ore of known mineralogical texture. Although the method is still at its infancy it may provide, when combined with a reagent conditioning model (e.g Niemi et al., 1982; Bazin et al., 1988), a way to simulate flotation without the need of entering the numerous parameters of a flotation model."

Jan 1, 1994

By Ferri P. Hassani, Riadh Bouzaïene

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

Jan 1, 1992

By E. E. Mueser

As Mr. Lundberg has already ably covered the theory of various methods of electrical prospecting, I shall confine my remarks to a consideration of the features which must obtain in an electrical prospecting method in order that it may be useful from a practical standpoint. These remarks I shall make with particular reference to the Elbof method. The successful application of all these methods rests, in the first place, upon the possibility of correlating theory, or empirically established facts, with the field data. Their practical usefulness, however, requires that the technique of making the field observations, and the procedure itself, be such that the method may be applied to large areas, under normal average conditions. The method, therefore, should not involve excessive preliminary labour costs to prepare the ground for actual prospecting work, nor should the prospecting work itself be so slow that its cost, when applied to extensive areas, becomes prohibitive. Moreover, it should be possible to apply the method even under difficult terrain conditions, such as rough topography and dense vegetation. It may be said of most of the methods referred to in the preceding paper, that, while they are interesting and theoretically sound, they fail to meet such practical requirements as I have outlined.

Jan 1, 1926

By M. Fairman

The effect of welding speed on the microstructure of friction stir processed (FSPed) AZ31B-H24 magnesium alloy was studied using light microscopy, image analysis, and microhardness tests. The grain size of the magnesium alloy was observed to increase after FSP from about 3.5 µm in the base alloy to about 8 µm in the stir zone. The aspect ratio decreased from 1.60 to 1.55 towards the center of the stir zone. The changes in the grain size and shape caused the microhardness of the samples to drop significantly across the FSPed region from 75 HV in the base alloy to below 55 HV in the stir zone. Decreasing the welding speed increased the grain size due to a greater input of heat energy. The faster heating rate due to the lower welding speed caused a deeper penetration of the annealing effects of FSP. It was also observed that the annealing effects caused by FSP were less pronounced with increasing distance from the interface between the sample and pin tool shoulder. The Hall-Petch type relationship of the micro-indentation hardness as a function of the grain size was observed to hold true after FSP.

Jan 1, 2007

By J. Jackman

North America has been aggressively pursuing approaches to improve the fuel efficiency of vehicles, and to develop alternatives to petroleum-based fuels used in automotive applications, for over ten years, Increasing energy demand due to emerging economies, coupled with probable peaking of conventional petroleum production in the coming decades are increasing the need to reduce dependence on petroleum-based fuels for transportation, Vehicle lightweighting is seen as an important strategy to improve fuel efficiency of conventional as well as highly innovative vehicles, Magnesium has recently emerged as a serious candidate for lightweighting, as a result of lower global prices, Automotive vehicles produced in North America currently use more Mg than vehicles produced elsewhere in the world, but the amounts per vehicle are very small in comparison to other materials such as steel, aluminum and plastics, The reasons, besides price, are primarily a less-developed state of technology for Mg in automotive transportation applications and lack of familiarity by the vehicle manufacturers with the material, This paper reviews the major government-funded research programs in the USA and Canada that are dedicated to advancing the state of Mg technology for automotive applications, It provides examples of research in the areas of high-pressure and other types of castings, corrosion solutions, sheet development and other wrought applications.

Jan 1, 2006

By H. T. Michels

Recent laboratory studies show that several bacteria, known to be human pathogens, die when they come in contact with copper and copper alloy surfaces. The amount of live bacteria drops by several orders of magnitude, to zero, on copper alloys in a few hours. In contrast, no reduction is seen in the concentration of live organisms on stainless steel during the six-hour test period. Aluminum painted and coated surfaces and plastics would show behavior similar to stainless steel and show no effect. Coatings and other surfaces claiming to be antimicrobial showed little to no effect. These results suggest the selection of copper alloys for surfaces exposed to human touch can materially assist in reducing the transmission of infectious organisms. In order to make antimicrobial claims in the United States, the approval of the US Environmental Protection Agency (EPA) is required. The EPA-required efficacy testing is described and the test results are summarized. It is anticipated, that once regulatory approval is obtained, that this will facilitate the introduction of antimicrobial copper alloys in hospitals, nursing homes and other healthcare facilities, as well as schools, and public buildings. Some of the application and barriers, to entry into the healthcare markets are mentioned.

Jan 1, 2007

By Timothy D. Dreger

In the spring of 2009, Suncor Energy Inc. technical personnel saw an opportunity to improve planning 0and mining of overburden material in order to address aggressive construction goals and increased mining complexity. By tying together current and historical equipment performance, geological model information, and material observation in the field new operating elevations for the shovels were developed. At the same time, methodology of recording and reporting overburden movement through the Modular Mining DISPATCH system was changed. The result of this first stage of improvements was an increase in construction-grade material available at the face. The personnel involved realized that other opportunities were available to build on the initial successes and establish processes that would stand up to attrition and experience levels. A cross-functional technical team was assembled to identify ways of further improving workflows around overburden mining. Some of the opportunities realized include greater alignment between planning, reporting and operations as well as development of reporting tools that help steward Mine Operations to the plan. All of which have resulted in Suncor meeting or beating its forecast overburden targets. The cross-functional technical team continues to seek out new and better ways of doing business so Suncor can continue to deliver on its commitment of outstanding performance and results.

May 1, 2011

By B. B. Meadows

"The Minto-Chipman Strip Mining Reclamation Project was initiated to re-vegetate the spoil piles remaining from strip mining operations.All available information was studied by the team responsible, and areas being reclaimed in the U. S. were visited, Methods applicable to the N. B. Project were noted for future use.We have both surface and underground mining operations in New Brunswick, Both deface the natural landscape and reclamation varies in difficulty, Surface operation disturbances are the most difficult to correct.Some of the surface mining is carried out next to two main highways and the results are definite eyesores, With this in mind, it was decided to landscape the spoil ground next to the highways and plant “as is"" the ground remote from the public view.The landscaping entailed various degrees of bulldozing from complete levelling to contouring, smoothing and topping, Bulldozing is, of course, the most expensive part of any reclamation project.There are two phases to the planting program; experimental and operational--experimental both prior and, later, in conjunction with the operational planting.Initially in the experimental project, the pH and composition of the spoil was determined using a grid sampling system. Soil samples were tested in a laboratory at the University of New Brunswick."

Jan 1, 1970

By H. J. Oterdoom

SMS Siemag (SMS) has always been the front runner in safety aspects of electric smelter plants for the ferro-alloy and non-ferrous industry. The awareness for safety increased significantly over the past decades and SMS contributed with its design features greatly to a safer design and operation. Today, safety aspects are not only part of the smelter design but also of the overall plant layout. Explosions in electric smelters are rare, but have a huge impact on peoples’ lives, on equipment and on production. For this reason, SMS wanted to have a better overview of explosions within the smelting industry in order to see if useful statistics could be extracted. Generally, there is a lack of statistics regarding explosions in the electric smelting industry, and not enough information is collected or published. A significant portion of the explosions seems to be water related. Many companies, both operating and engineering, are trying to handle the risks of water, and apply methods to detect water leakages. Installing such a system is a management decision and management has then to make sure the system is properly implemented. The disadvantages and limitations of these systems should be carefully considered and communicated to operators and authorities.

Jan 1, 2014

By C. F. Hews, P. N. Calder

"MIROC and The Mining Industry The Mining Industry Research Organization of Canada (MIROC), incorporated in 1975, is a non-profit organization sponsored by member companies from within the Canadian mining industry. The Canadian mining industry is a world leader in technological development and in organizational and human resources development. A prime objective within the industry is to retain this leadership and also improve its competitive position worldwide.MIROC is dedicated to support the objectives of its member companies and their common interest, and the objectives of the industry. In this context: MIROC's mission is to encourage the formulation of ideas to improve mining technology and methods by any source, and to foster the development and testing of promising initiatives in progressive steps from the early stages of conceptual and feasibility research through manufacture to delivery of new technology to the mining industry. In so doing MIROC plays an important role in the development of individuals skilled in mining research. Management ApproachMIROC's research program is driven by member companies who have interests throughout Canada. The board of directors approve projects that are acceptable to its members. While MIROC's basic research funding is provided by its member companies, about 30% of its annual research budget is now derived from royalties generated from previous research activities."

Jan 1, 1994

By Hans Lundberg

The magnetometer which was developed during the war for detecting submarines has proven exceedingly valuable in outlining deep-seated structures in oil exploration, and will be useful also to geologists in outlining regional structural features in the Precambrian. Our magnetometer has been developed to outline local and detail structures. 1 am quite sure that all geophysicists and geologists would agree with me that, in ore prospecting, it is important to obtain as much detailed information as possible. We know that, as we ascend from the ground and get away from the magnetic ore-bearing structures and orebodies, the magnetic intensity decreases rapidly, but, worse than that, we lose the details even faster. Figure l shows two strong, very sharp, magnetic 'highs' over two orebodies which, as our distance increases, rapidly merge into one fairly broad, moderately strong anomaly. If we drilled on this maximum, we would not encounter any of the orebodies. Therefore, we should fly the airborne magnetometer as close to the ground as possible in order to duplicate the results of the magnetic ground surveys. The first chance to accomplish this came with the helicopter, which is an exceedingly maneuverable aircraft. It can be landed in a cleared space not much more than fifty feet square. With floats, it can be landed anywhere, even in a swamp, on thin ice, or on soft snow. It can stand still in the air, hovering over a given point. It can ascend and descend vertically, fly sideways and even backwards, at the will of the pilot. It flies forward at any speed up to l00 miles an hour. The helicopter can be taken to any desired position at a given time. It can fly at any useful altitude from a few feet to several thousand feet above the ground. It can fly very close to the ground with safety. In bare areas, the survey flight may be performed a few feet above the ground. In forested areas, however, the flights, to clear the trees, must be made at l00 to 150 feet. To mark out a certain point, a small parachute-like marker may be draped over a tree or laid on the ground. This can be done from the helicopter without touching the ground.

Jan 1, 1947

By G. Vibert Douglas

IN a previous paper by Douglas and Gillies (1), a simple field test was given for gold. Later work by the present writers, and by others who have kindly written to us, shows that the test is not as satisfactory as it was hoped. In many cases, the gold mirror is completely obscured by a dense precipitate which, up to the present, it has been found impossible to remove. After many attempts, we have temporarily given up the iodine test and have been working on a simple pyridine reaction based on the work of Putnam, Roberts, and Selchow (2): The ore to be tested is ground to a fine flour. Place half a gram of this powdered ore (an amount that will cover a Canadian ten-cent piece, not heaped) in a six-inch test-tube and add 5 c.c. of aqua regia. The aqua regia. should be made up on each occasion, using four parts of hydrochloric acid and one part of nitric acid, both concentrated. Shake the solution in the test-tube for about one minute and allow to settle until dear. The rime to settle may be 30 to 60 minutes. When dear, a drop of the solution is with-drawn with a fine, dean eye-dropper or capillary tube and placed on à small glass plate. A slide such as is used for mounting rock sections is suitable. Now place an equal sized drop of pyridine solution on the plate beside that of the aqua regia solution to be tested. The pyridine solution, containing nine volumes of hydrogen bromide to one volume of pyridine, can be made up in advance and carried in a glass-stoppered bottle. Join the two drops with a glass thread or fine, dean stick, and allow the merged drops to stand undisturbed. I t is well to place the slide on a piece of white paper so that the presence of the crystals which may form can be easily seen. The time for their formation will vary with the amount of gold present, but the slide should be allowed to stand for at least 30 minutes before negative results are reported. A hand lens of at !east ten magnifications is essential. If gold is present, minute red crystals will form around the margin of the drops as these drops slowly evaporate.

Jan 1, 1938

By B. S. Riess

A novel design for an automated uranium pellet stacking system is presented. This system is designed as a drop-in solution to the current production line to enhance the fuel pellet stacking process. The three main goals of this system are to reduce worker exposure to radiation to as low as reasonable achievable (ALARA), improve product quality, and increase productivity. The proposed system will reduce the potential for human error. This single automated system will replace the two existing pellet stacking stations while increasing the total output, eliminating pellet stacking as a bottleneck in the fuel bundle assembly process.

Aug 1, 2010

By Walter Curlook

"With Inco recording record profits over the past year, most people have forgotten the painful years of the last recession/depression when Inco was losing up to a million dollars a day for a short period . While high nickel prices have contributed to the exceptional recent profits, the real achievements stem from the tremendous advances in productivity and cost improvements that make Inco one of the lowest cost nickel producers.Some of the major advances in productivity have occurred in the mines. The establishment of Mining Research Departments in both Thompson and Copper Cliff in 1979/80 provided the stimulus and the opportunity to dedicate personnel to specific research projects, on a full-time basis; and more particularly to concentrate on the efficiency of the total mine system. The Copper Cliff North Mine was brought back into production as a research mine dedicated to the development and testing of new mining methods and equipment. A shop facility known as the ""Murray Shop"" was set up as the centre of innovation for the development and construction of prototype equipment required for new bulk mining methods. While other expenditures were being curtailed , investment in mining research was being increased. An early success was an ""in the hole"" drill that could be broken down into small components to access even the remotest sectors of a mine to convert labour intensive undercut-and-fill mining to "" vertical crater retreat "" , VCR, bulk mining. A new mine manufacturing company-Continuous Mining Systems-was incorporated with the objective of building innovative mining equipment, with strong focus on automated continuous sytems. Continuous Mining Systems has now grown to a $25 million per year business. With these synergistic thrusts, the VCR bulk mining method was implemented in all of the Ontario Division mines, raising the percentage of ore mined by bulk mining techniques from 320/0 in 1981 to over 90% today. Coupled with re-designed job responsibilities, sup- ported by appropriate training, mine productivity more than doubled. It was discovered that VCR mining could be adapted to the narrower Thompson mine ores with identical improvements in productivity. Development of the Thompson Open Pit North had an additional favourable impact on production cost s in Thompson. The timing of the open pit development could not have been better. It permitted Inco to rapidly increase production at high productivity and low cost, in years of record demand and prices."

Jan 1, 1990

By Mario Giavani

"IntroductionBy the 1980s, the continuous casting process had almost replaced the ingot casting of steel in Japan, Europe and North America. While economic benefits were probably initially the prime motivator, the transition rapidly proved that continuous casting in conjunction with ladle metallurgy offered a much greater degree of process control and made possible routine steel specifications not previously available.This new technology demanded improved procedures for the quantitative addition of the required metallurgical reagents, especially as regards the more volatile or toxic elements such as calcium , boron, carbon, sulphur, lead and tellurium. The injection of a thin steel tube containing the additive into the metal bath of a ladle refining station offers the best procedure for this. In the industry this has been referred to as ""Cored Wire "".Operators using this technology find that they are faced with balancing the injection speed against the small cross section of the tube to feed the required amount of reagent within the short time span available to the operation. Large-ladle shops requiring major quantities usually resort to multiple machines and high speeds. Many machines approach a maximum feed rate of 400 m/min. Higher speeds exceed the melting rate of the system, and the ferro static buoyancy of the tube will cause it to coil up the ladle wall and possibly resurface into the slag layer, and even eject itself above the surface. Under these conditions, exact control of element recovery becomes difficult, especially with the commonest addition, calcium silicon alloy.Many experts are persuaded that the final melting position of the carrier tube has major importance in establishing consistent element yield to the bath.For instance, the vapour pressure of calcium at l500 °C is close to I bar. Reaching a melting depth sufficient to accommodate this value is considered to be critical to achieving an acceptable and reproducible yield.Many studies have elaborated semi-empirical formulae to establish the melt zone depth, connecting this value essentially to the diameter of the tube , the injection rate and the superheat of the steel. The author's experience in steelmaking could not confirm such formulae in many cases, and he set about to develop a mathematical model which would be useful in addressing this problem, taking into account the several parameters which will regulate the behaviour of a filled tube immersed in molten steel."

Jan 1, 1991

By A. Ghahreman

Activated carbon is proven to be able to catalyze arsenic oxidation in aqueous solution under acidic conditions. A commercially available granular coconut shell based activated carbon (AC) has been evaluated for catalysis of arsenic oxidation in this study. The rapid small-scale column test (RSSCT) has been developed to simulate and predict the performance of a carbon-based arsenic treatment system in a pilot scale reactor. Effects of residence time, aeration rate, and initial arsenic concentration in the influent solution on the AC catalysis of arsenic oxidation under dynamic and continuous conditions were studied by manipulating these parameters during RSSCTs. The effectiveness of the AC on arsenic oxidation was examined over the course of constant diffusivity based RSSCT operation. Residence time and initial arsenite concentration are proven to be the most effective impacting parameters on the arsenic oxidation process. For the 218 min residence time, the highest steady-state arsenic oxidation efficiency achieved was 98% with 1 g/L As(III) being treated at pH=1 under 0.05 L/min oxygen aeration. In a long-running RSSCT, the oxidation efficiency did not seem to deteriorate over a course of 666 hours operation, corresponding to 13986 mL total influent throughput volume. INTRODUCTION Arsenic is toxic to both animals and plants and inorganic arsenicals are proven carcinogens in humans. The increased extraction of low grade and complex mineral resources has introduced high ratios of arsenic into metallurgical processes. Discharge of arsenic by acid mine drainage resulting from mining activities has added intensive pressure on the need for proper treatment (Lawrence & Higgs, 1999). Since trivalent arsenite is more toxic and has lower affinity to solid surfaces for adsorption, many treatment systems initiate with an oxidation step to convert arsenite to arsenate and reach the ultimate immobilization of arsenic by the following precipitation of arsenate (Nazari, Radzinski, & Ghahreman, 2016). Scorodite precipitation has been studied extensively as a means of arsenic immobilization due to its high stability and negligible potential of releasing arsenic (Filippou & Demopoulos, 1997). As a stable ferric arsenate mineral, crystalline scorodite can contain up to 30 wt% arsenic (Paktunc, Dutrizac, & Gertsman, 2008). Arsenic must be in its pentavalent oxidation state in order for scorodite to be precipitated via oxidizing ferrous ions (Clancy, Hayes, & Raskin, 2013).

Jan 1, 2019

By R. Stauber, B. Friedrich, S. Hilgendorf, G. Homm, C. Gellermann

Due to recent regulations limiting tolerated lead concentrations in copper alloys, new recycling strategies have to be considered. This study investigates the suitability of technical approaches in order to recycle leaded copper alloys exemplified by CuZn39Pb2 and produce an alloy in compliance with future lead regulations in the European Union. Three pyrometallurgical methods are considered to achieve this goal, namely vacuum distillation, intermetallic precipitation and fractional crystallisation. The impact of essential process parameters i.e. pressure, temperature, time, atmosphere and quantity of additives are identified using thermochemical and kinetic modelling. An experimental implementation reveals a general suitability of all three refining processes. However, the individual efficiency of the different methods strongly differs. Thus, a detailed assessment is carried out in order to provide an evaluation on the efficiencies of these methods from a technological, economical and environmental point of view. Taking a possible industrial realisation into account, the authors recommend the approach of vacuum distillation, although the energy demanded is comparatively high due to the enthalpy of evaporation for zinc, or rather, lead. However, required lead concentrations can be reached quickly without introducing an external element to the material. The prediction of selectivity and evaporation speed, which are immanent variables for a successful implementation, can be validated experimentally. INTRODUCTION In 2016 approximately 1 million tonnes of leaded copper alloy semi-finished goods with an average lead content of 2.1 Ma% have been produced in the European Union (EU). The global production in the same period exceeded 5.5 million tonnes, while the lead concentration has stayed constant at around 2.4 Ma% for the last 50 years. Up to 80 % of the current production volume is covered with end-of-life scraps, which are used for direct re-melting, depending on the alloy composition. Lead has been a popular alloying element in copper alloys in general, and in particular in brass due to its positive impact on various mechanical, physical and chemical properties, especially machinability. Health and environmental concerns were drivers for many governments to implement limitations on lead. In order to further utilise the resource potential of leaded copper scrap, it is inevitable to develop methods to efficiently eliminate lead from circulation as far as possible. (Glöser, Soulier, & Tercero Espinoza, 2013; Soulier, Glöser-Chahoud, Goldmann & Tercero Espinoza, 2018)

Jan 1, 2019

By Esa Peuraniemi, Hanna-Leena Heikkilä

Boliden Harjavalta has been operating a copper flash smelter since 1949. Thus, in 2019, the smelter is celebrating its 70th anniversary of flash smelting. Slag formation is an integral part of the smelting process; currently the processing of slag is based on froth flotation at the slag concentrator. It provides high recovery of copper but restricts slag utilization; the final copper slag is deposited in a landfill. The Harjavalta smelter commissioned a new landfill area for final slag in May 2018. This paper describes the full project from permitting to commissioning of a new landfill area. The permitting process is described comprehensively, including environmental impact assessment together with the environmental and dam safety monitoring. During the environmental impact assessment, observations on rare animals protected on European level were made as well as archaeological findings. Successful completion of the permitting allowed the construction phase to start on time. After six years of intensive work, the new landfill was commissioned in May 2018. The new landfill area provides a sustainable way to store the smelter’s slag for decades to come. INTRODUCTION Slag processing Sulphide based concentrates have always formed the main raw material stream at Harjavalta’s copper smelter. During the smelting and converting steps, the iron included in the concentrate is oxidized and fluxed using a silica-based sand. Originally, the slag was processed by using an electric slag cleaning furnace after which the final slag was water granulated. Froth flotation has been utilized for slag treatment since 1966. In the beginning, the slag was cooled in open ditches. In 1984, controlled slow cooling of slag was licenced to enhance copper recovery at the flotation plant. Today, the slag from both the smelting and converting is tapped/skimmed to slag ladles and treated in the following steps: Slag ladle transportation from the smelter to the cooling area by slag hauler Slow cooling of slag in the ladle to allow mineral precipitation Unloading the slag by tilting the ladle; causing the slag to crush as it drops from the ladle Feeding the crushed slag (-500 mm) by wheel loader to a slag concentrator’s feed funnel followed by a conveyor belt transporting the slag to the concentrator plant Crushing and grinding using lump and pebble mills Froth flotation of the valuables Recycling the slag concentrate back to the smelter feed after dewatering Pumping the final copper slag to the landfill area.

Jan 1, 2019

By Robert B. Parsons

"New Brunswick Finance Minister John Baxter pulled something out of a hat for the mining industry in April, but there is a general concensus in the industry that he should put II back where it came from.The industry has never been in the mood f or progressive rate structures, but that is exactly what New Brunswick 's 1984 budget offers to this depressed sector of the economy.IntroductionThe Province of New Brunswick stunned the Canadian mining community in April with the announcement that the province' s 16% mining tax rate would be replaced with a progressive rate structure effective January 1, 1984 (Table I). The proposed change, contained in the bud get papers tabled by Finance Minister John Baxter on April 17, caught the industry totally by surprise. The move to a progressive rate structure was completely unexpected for a variety of reasons:• Generally speaking, relations between the province and the industry have been relatively good, yet the industry was apparently not consulted with respect to the proposed measure and had no indication that a change of th is nature was coming. This is in stark contrast to the mood which prevailed during the major revamping of the province' s mining tax regime in 1977: at that time, the industry was invited to contribute in advance to the province's plan for a new tax structure.• The new structure would appear to make th e province less competitive in terms of mining tax rates with Ontario , Quebec, and other provinces, despite indications in the past that New Brunswick is very cognizant of this competitive factor in formulating mineral policy.• A joint report in November 1978 by federal and provincial officials to federal and provincial finance and resource ministers, which was careful not to directly criticize Ontario and Quebec's progressive mining tax rate structures, recommended that provincial "" tax regimes be examined to ensure the inclusion of appropriate mechanisms to avoid the excessive taxation of cyclical type profit "" , and that ""the federal and provincial governments consider the concern over progressive tax regimes expressed by the industry and examine mining and royalty tax regimes and the income tax regime with a view to alleviating the effect of such regime on the aggregate marginal tax rate"". In this context, any move to a progressive rate structure would be viewed by many observers as retrograde."

Jan 1, 1984