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By H. J. McQueen

The modeling of the extrusion of 6061 alloy and its composites with 10 to 20 vol% Al203 or SiC by two techniques. The uniaxial finite element method FEM (DEFORM" ) provided force-stroke curves and temperature rise over the range 450-500 °C, 2.6-5mm/s and extrusion ratios of 31 and 64. The traditional technique considers ideal work and redundant work as well as friction and uses average temperatures and strain rates. The two techniques are used to clarify each other and to extend the analysis to 400 and 350 °C. The calculated efficiencies are compared to measured values in extrusion trials and to values derived for 7075 extrusion analyses. The analyses are based on constitutive equations determined by torsion testing tests.

Jan 1, 2004

By F. R. Archibald

Introduction It is the purpose of this paper to review the subject of roasting as preparation of refractory gold ores and concentrates for cyanidation, with particular reference to operations at the mill of Beattie Gold Mines (Que.), Ltd., Duparquet, Quebec. Two earlier papers relating to the Beattie roasting operations are cited as background to the ? present discussion, and more general reference is made to other publications relating? to geology and metallurgy at Beattie. The Beattie roasting plant was built in 1937 as an addition to the existing flotation and cyanidation plant to permit complete processing of the ore at the mine property. Previously, the flotation concentrate had been cyanided, yielding 70 per cent of the gold values, followed by re-flotation of a concentrate from the cyanide residue. This re-floated residue was shipped to a smelter for recovery of gold values unavailable from direct cyanidation. The roasting plant itself is of interest through application in its design of multiple-hearth roasters and a Cottrell plant for separate recovery of dust and arsenic. In the laboratory and plant studies that accompanied development of the plant into a dependable and efficient working unit have been found principles and ideas applicable to other roasting 'problems. Before enlarging on these aspects relating particularly to the Beattie problems and plant, brief consideration is given to roasting in general.

Jan 1, 1949

By P. Moreno

ABSTRACT: The Maras salt terraces, located between Cuzco and Urubamba in the Andes (southern Peru), are living examples of traditional Incan salt production, where present-day artisanal miners produce salt from shallow pans by solar evaporation. In these terraces, natural spring water, eight to nine times saltier than seawater, is used to produce the salt. The field observations and chemical analyses show that the poorly crystalline traditional salt is finer in particle size and contains impurities such as dolomite and gypsum. These differences are the result of shallow pond depth, contamination from wall erosion, and the nonsequential mode of salt crystallization.

Jan 1, 2011

By J. G. A. Stevenson

"IntroductionDURING the past quarter of a century diamond drilling, in all its phases, has increased in Canada to a very impressive total of more than 10,000,000 feet annually. Since the art of diamond drilling became recognized, some seventy-five years ago, there has been considerable improvement in both equipment and technique. The steam-powered drill rig and the hand-set diamond bit are things of the past.The purpose of this paper is to review some drilling trends •and practices over the past few years. In the preparation of the paper, the author wishes to acknowledge kind assistance of Mr. J. D. Cumming, Dr. C. H. Hitchcock, Mr. Robert H. Quintal, and many others, including staff members of the Longyear organization.Figures provided by the Dominion Bureau of Statistics for the year 1954 show that Canadian production of metallic and non-metallic minerals and structural materials had a value of $1,454.2 million, excluding radioactive products for which figures are not available. Approximately 61 per cent of this valuation comprised production of nickel, copper, gold, coal, asbestos, zinc, lead, and iron. It is certain that diamond drilling played a major role in the discovery and development of the orebodies from which these minerals were obtained.After the surface examination of an ore deposit, diamond drilling will automatically follow, in order to determine structure, grade, and tonnage.Footage drilled by mining companies and contractors on mineral exploration and blast-hole work since 1945, as reported by the Do-minion Bureau of Statistics, is shown in Figure 1."

Jan 1, 1955

By T. Feldmann, G. P. Demopoulos

The feasibility of chloride leaching processes depends on interfacing them with cost-effective HCl regeneration technologies. This paper summarizes the most important findings of research conducted in the past 3 years concerned with a novel process to regenerate high-strength HCl from concentrated CaCl2 solutions at temperatures below 100°C, via reaction of CaCl2 with H2SO4 resulting in the formation of calcium sulfate phases (gypsum, a-hemihydrate or anhydrite). From constant supersaturation semi-batch experiments in pure solution it was found that the crystal growth rate of hemihydrate, and hence the particle size, was influenced by the rate of reagent (Ca2+, SO4 2-) supply to the reactor. Additionally, growth studies of DH in presence of impurities (K+, Mg2+, Sr2+, Ba2+, Fe2+/3+, Al3+, La3+, Y3+, F- and PO4 3-) showed that specifically Sr2+ and PO4 3- are taken up during crystal growth. Furthermore, it was found that decreasing water activity (via different HCl/CaCl2 concentrations) and increasing temperature reduce the metastable life-time of DH and HH by increasing the phase transformation speed. The DH/HH transformation was identified to be dissolution-precipitation based, while HH to AH is a topochemical process. Finally, continuous experiments on bench scale are underway to confirm the feasibility of the process to obtain super-azeotropic strength HCl with up to 9 mol/L (~30wt.%) from 5 mol/L CaCl2 (~40wt.%) solution.

Jan 1, 2014

By Rob Assabgui

Presentation Overview ? Stobie Mine Sublevel Cave Background ? Elevated Silica Levels ? Silica Control ? Challenges and Issues ? Conclusions

Oct 1, 2010

By I. P. Swainson, A. Ilbagi, H. Henein

Powders of Al-50wt%Ni, Al-40wt%Ni and Al-36wt%Ni were produced using the Impulse Atomization technique, a rapid solidification technique. The molten droplets were cooled in-flight by the stagnant helium or nitrogen in the atomizing chamber. The resulting powders were sieved into different size ranges. X-Ray diffraction and neutron diffraction were used in order to quantify the phase fractions in the samples. The computer software GSAS was used to calculate the weight fraction of the existing phases, namely Al3Ni2, Al3Ni and Al, by profile refinement method. The effect of processing parameters, alloy composition and particle size will be discussed in this paper. In brief, no AlNi was found in any of the samples analyzed. Higher cooling rates resulted in the reduction of the ratio of Al3Ni/Al3Ni2. Also, at high cooling rates, Scheil closely predicted the ratio of Al3Ni/Al3Ni2. Some metastable phases were found in Al- 36wt%Ni.

Jan 1, 2010

By J. W. Meier

Introduction The great importance of air warfare during World War II and the introduction of large-scale air transportation and airborne operations created an immediate demand for large quantities of high quality light alloy products. Before this war, the use of magnesium, the lightest structural metal, was barely in the development stage, and considerable research work was needed to overcome difficulties in improving its properties and to attain uniform quality in mass production of magnesium alloy products. The Canadian Bureau of Mines was frequently called upon, by various agencies of the Armed Forces and of the newly established war industries, to examine magnesium alloys that had failed in fabrication or in actual service, and to advise on proper alloys and fabrication methods to be used. Failures in magnesium alloy castings were connected mainly with lack of knowledge of proper founding and surface-protecting techniques. Most of the defects were due to microporosity and faulty heat treatment. To aid the foundry industry, small-scale investigations were started on the effect of various factors in the casting technique in order to improve the quality of the products. These investigations were made in co-operation with representatives of the Armed Forces and the Canadian magnesium industry. This work was later co-ordinated into a broad research programme on magnesium alloys, comprising problems on melting, refining, various casting methods, heat treatment, and testing of properties of standard and special alloys. This research programme? is still in force, and the present paper contains some results of the first series of investigations on magnesium casting alloys carried out at the Experimental Foundry of the Bureau of Mines.

Jan 1, 1948

By A. R. Pasieka, J. C. Wilson

"Compressed air still remains an essential source of power in underground hardrock mining. As a power medium it has a high convenience factor, although, in many cases, it is expensive to generate and maintain. Until new methods of breaking rock and/ or satisfactory alternatives to air-driven rock drills are developed, compressed air is indispensable. It is essential to utilize this source of power to a maximum by keeping all pneumatic tools supplied with air in adequate quantity and at optimum pressure.In search of the optimum operating air pressure, con-trolled drilling tests were undertaken at dynamic pressures ranging from 90 to 140 psi.Test results show the effect of increasing air pressure on: the performance of various jackleg drills at varying pressures, the life cost of drill steels and TC bits, and drilling efficiency at varying pressures. From the fore-going, a criterion is proposed for selecting efficient rock drills, and, also, optimum air pressure at each mine can be determined for its particular conditions."

Jan 1, 1966

By M. Fairclough, B. Moldovan

Insights into uranium mining projects of the future can be gained by a careful statistical analysis of past and present deposits, as well as an examination of recent trends for uranium resource evaluation and primary uranium production. The International Atomic Energy Agency (IAEA) provides the necessary data and corresponding mechanisms as inputs for methodologies that enable strategic and scientific evaluations of long-term security of supply uranium required to sustain the demand for nuclear fuel. Sustainability of the uranium mining industry and subsequently new uranium mines of the future requires innovation and expertise to lower operating costs, maintain or improve uranium recovery while meeting the requirements of stakeholders in regard to protection of the environment and safety of the workers and general public.

Jan 1, 2020

By J. W. Meier, J. O. Edwards, R. C. Bell

"IntroductionTHE DIE CASTING industry .as we know it today is the direct result of the invention and development of die casting machines during the nineteenth century and of reliable alloys in the twentieth. The early machines were designed to cast low melting point metals such as lead .and tin, and their alloys.It was inevitable that, as these die castings were put into service, the demand should arise for stronger materials. Zinc alloys, often containing lead, tin, copper, and aluminum as major constituents, were relatively easy to cast and stronger than the lead and tin alloys. However, it became apparent after a number of years that these zinc alloys tended to become brittle, distort, and corrode, particularly if kept in warm, humid atmospheres. Thus, considerable quantities of zinc-base .alloys were in use before the trouble was realized and effective measures could .be taken to determine the cause of the instability.The deleterious effect of certain metallic impurities on the properties of zinc •die casting .alloys has now been known for about thirty years. Brauer .and Peirce, and, later, other research workers of the New Jersey Zinc Company such as Anderson and Werley, discovered the pronouned effect of lead, cadmium, and tin on the stability of zinc-alloys."

Jan 1, 1952

By B. Kenney

For SOFCs, composite cathodes comprising an electronically conducting electro¬catalyst (e.g. LSM) and an conically conducting electrolyte material (e.g. YSZ) are considered to improve the electrochemical performance by extending the active reaction zone to regions beyond the electrolyte-electrode interface, as in the case of conventional cathodes. Interpretation of experimental data for composite cathodes, however, is complicated by the mixed conducting behaviour which results in local overpotential distributions throughout the composite cathode. These local overpotentials depend on many factors, such as the composition, particle size, porosity and thickness of the cathode. Reliable experimental data obtained from composite cathodes requires carefully crafted microstructural parameters in order to minimize the overpotential variations. A mathematical model of a composite cathode was developed using coupled differential equations describing transport and consumption of chemical species, oxygen ion and electrons. Simulations under various oxygen concentrations were used to obtain the reaction order of the oxygen reduction reaction. An apparent po2 dependency was then extracted from the predicted Rp vs P02 data. It was found that this p02 dependency can be significantly influenced by the micro-structural parameters of a composite cathode, primarily due to local overpotential distributions.

Jan 1, 2005

By A. Galip Ulsoy, K. V. S. Sastry

"This review paper is intended to provide, the mineral process engineer with an introduction to the concepts, terminology. and practice of mineral process control. It also provides an extensive sampling of the vast body of literature relevant to this topic. The topics discussed include the principles of automatic control, instrumentation, mineral processing unit operations, process modeling and simulation, and process and plant control. IntroductionEconomically accessible higher-grade ores are being rapidly depleted, and at the same time the demand for mineral raw materials continues to increase. Mineral recovery from the remaining low-grade or finely dispersed ores requires grinding for liberation. High energy consumption during grinding and poor efficiency associated with the beneficiation of fine minerals are two important problems facing the mineral industry . These problems, coupled with advances over the last 10 to 15 years in the areas of process modeling, instrumentation, computer technology and control theory, have made automatic control of mineral processing systems an important research area(23,52,66,67,120,129,152)."

Jan 1, 1981

By A. Galip Ulsoy

This review paper is intended to provide, the mineral process engineer with an introduction to the concepts, terminology and practice of mineral process control. It also provides an extensive sampling of the vast body of literature relevant to this topic. The topics discussed include the principles of automatic control, instrumentation, mineral processing unit operations, process modeling and simulation, and process and plant control.

Dec 1, 1981

By M. J. Davie, D. S. Ross

"The successful design of a new mine water pumping system is in part dependent upon the accuracy with which the operating conditions can be forecast. This paper outlines the data which should be obtained on water quantity and quality. Methods of modifying the quality are also discussed. Some pumping systems for disposal of sludge are described, citing operating examples. The various types of mine dewatering pumps are described in terms of design characteristics as they affect operating efficiency and installation and maintenance costs. Piping system parameters are outlined. Finally, a hypothetical case study of pumping from a depth of 3,000 ft is assessed, with particular reference to capital costs.IntroductionMany mine operators would agree that the pumping system usually receives a low engineering priority during the design stage, and as a consequence causes some of the most frustrating problems during production. For a ""dry"" mine (up to 200 gpm), design of the pumping system may indeed be simple, but outside of the potash industry such mines are not common. For ""wet"" mines, the pumping system is important because it significantly affects the initial capital and on-going energy costs of the mine and, in the area of sludge disposal, the working conditions and production costs. Indeed, a failure in the pumping system usually has serious, and sometimes disastrous, consequences.The intent of this paper is to outline the factors which should be considered in the design of a pumping system and to describe the types of pumps used in mine dewatering and relate them to practical operating systems."

Jan 1, 1980

By A. E. Cameron

The curve of coal production in Nova Scotia over the past forty years shows a definite maximum reached in 1913. Continued production to this maximum will require a greater tonnage per man-day, and this means there cannot be any increase in total man power used in the operations. There are still large reserves of coal but much of it will require washing or beneficiating to make a usable product. By-product recovery based on the present product ion is relatively satisfactory. Further development of secondary industries requires adequate markets for the bulk materials produced by the processing. It also requires access to other raw materials as well as markets for the principal product of the operations. Scientific investigation and research are needed to prove the quantity and value of lower grade or poorer quality coals, and methods for their recovery and utilization. Economics of further processing of present and future production must be investigated beforehand, if a successful development is to be assured. Such development cannot be expected largely to replace present markets. Production of coal for genera l use must continue to form the major function of the coal industry of the Province. Costs per ton must decrease, or subsidies or other assistance must increase, if the industry is to survive. Costs of investigation and research and costs of capital outlay for further development muse be met.

Jan 1, 1944

By A. Makinen

There is an increasing trend between increasing consumption of water and the production of metal concentrate. Along with this trend we see that ore grades are declining and getting more complex to concentrate around the world. This will not only complicate processing but also generate new requirements for the management of water and waste streams on mining sites. The mining industry is a large user of water and its water consumption is growing rapidly. The processing of lower quality ores requires greater volumes of water. For these reasons, the need for efficient use of water and water management at mine sites is becoming more urgent. The perception of water in the mining industry has changed from thinking about it only in terms of "water treatment" to actually seeing it as a valuable resource, a resource that needs proper management. This resource management needs to involve various aspects, such as optimizing water usage of the entire mine or concentrator site, minimizing fresh water usage, minimizing or eliminating waste generated in water treatment and implementing practices for water reuse and water recycling. This paper presents trends and new developments relating to waste and water management in the mining industry.

Jan 1, 2015

By J. A. Finch

In this paper, the author offers a personal view of what the next 30 years holds for mineral processing. Restating that mineral processing will remain a vibrant industry in raw material production, growth opportunities in waste management are identified. The processing sequence familiar now (mining ?mineral processing ?extraction) will become more interwoven. In situ processing (i.e., milling underground) will evolve from concept to demonstration. Opportunities to exploit physical properties altered in chemical (pyro- and hydro-) processing will present themselves. In primary grinding, the path to AG/SAG milling will progress with little deviation but opportunities in regrinding are wide open. Flotation will see the trend to designing bubble/particle reactors accelerate simultaneously with a vigorous response from mechanical cell suppliers. Gravity separation remains a bastion of the lone inventor but this author anticipates that the new lines will come from the waste management business. The paper concludes with the examination of the “research cycle” and identification of growth in small “high tech” companies and university research centres

Jan 1, 1998

By D. J. Robertson

"THE copper smelting operation of the Hudson Bay Mining and Smelting Company, Limited, at Flin Flon, Manitoba, generates a gas flow of 350,000 c.f.m. at n.t.p. This gas stream passes to atmosphere through a 20-foot diameter by 250-foot brick stack, carrying with it an appreciable dust burden in the form of metallic oxide fumes. The flow constituents during the period 1952 and 1953 and •before gas filtration was included in the treatment scheme are shown in Table I. This paper describes the gas filtration treatment which was installed in 1957, using glass cloth media to recover this dust burden, and discusses the associated problem as its treatment for recovery of zinc and cadmium.The metallurgical details associated with the problem are illustrated by a description of the material flow sequence of the Company's hydrometallurgical zinc plant and copper smelter. In this ore processing complex, the zinc plant and copper smelter form an integrated unit within which intermediate zincrich products of each operation enter the treatment circuit of the other."

Jan 1, 1960

By M. T. Shehata, R. W. Revie, M. Elboujdaini

Environmentally assisted cracks in linepipe steels are initiated either as a result of stresses in combination with environmental effects, as in stress corrosion cracking (SCC), or as a result of trapped hydrogen in the steel, as in hydrogen-induced cracking (HIC). To understand better the mechanism of the crack initiation process, key metallurgical and environmental elements that can affect the cracking phenomena were investigated and are reviewed in this paper. The complexity of both cracking phenomena results from the dependence of SCC and HIC on multiple metallurgical, mechanical, and environmental parameters that may all influence both crack initiation and propagation; e.g., composition, microstructure and non-metallic inclusions in the steel, applied stress, water chemistry in the field, and ionic concentrations in the groundwater near the pipe surface to name a few for SCC. In addition, for HIC phenomena, one can add the concentration of H2S in the fluids transported in the pipe as well as concentration of CO2, pH, etc. In this paper, cracking of linepipe steels is analyzed critically, with particular attention to the crack initiation process. The paper is divided into two parts: The first part covers SCC and the second covers HIC.

Jan 1, 2005