Search Documents

By R. J. Lipp, I. Iwasaki, R. H. Heerema

The presence of calcium ion in iron ore pulps that are upgraded by selective desliming can result in indiscriminate flocculation of both iron oxide and siliceous gangue slimes. In order to overcome this adverse effect, deflocculation by three complexing agents, namely ethylenediaminetetzaacetate (EDTA), sodium tripolyphosphate (STPP), and sodium hexametaphosphate (SHMP), was investigated. The precipitates and complexes of these agents with calcium ion were characterized by potentiometric and conductometric titrations, and the surface properties of quartz and goethite were studied in the presence of calcium ion and of the complexing agents by means of streaming potential measurements and flotation tests. The results were then correlated with selective flocculation tests on an artificial mixture of quartz and goethite. EDTA markedly improved the selectivity of flocculation when added in near stoichiometric amounts, whereas STPP was less effective and SHMP was totally ineffective due to strong, indiscriminate dispersion. Remanent calcium polyphosphates on the goethite surface interfered with the adsorption of starch flocculant.

Jan 1, 1983

By M. S. Oudenhoven

This Bureau of Mines investigation was conducted to obtain an experimental solution of stress changes in the vicinity of a circular opening in an infinite plate. Plates were stressed biaxially in compression and subjected, by four different-length shoes, to a uniform pressure at opposing points on the opening periphery. The principal stresses along the vertical and horizontal axes, which result from peripheral pressure, were obtained from the photoelastic analysis of four frozen-stress epoxy models. These principal stresses were then super-imposed on the mathematically determined principal stresses (along the same axes) obtained from a theoretical biaxial stress field in which the magnitude of the lateral pressure was one-third that of the vertical pressure. The results indicate that an increase in shoe length increases the radial compressive stress and the tangential tensile stress (except tangential compression at r/a = 1, which exists for all shoe lengths). Also, a partial control of the stresses within one-half radius of the opening surface is accomplished by a change in the magnitude and placement of peripheral pressure.

Jan 1, 1966

By William McFerren, Pragasen Moodley

In contrast to global trends, African, especially South African, surface mining operations have shown a significant rate of adoption of Electronic Detonators (ED’s) over the last few years. Proven benefits of converting to ED’s from pyrotechnic initiation systems have aided this market conversion. These benefits are experienced throughout the mining operation. Benchmarking exercises, prior to the introduction of ED’s, form part of the conversion process and allow for quantifying improvements. Extensive work has been done on quantifying the benefits of converting to ED’s and have shown that results can be reproducible. Improvements have been experienced in many applications and include environmental impact control, improved mining efficiencies, increased cast benefit and improved size distribution. These step changes in blasting results, in conjunction with the adoption of ED technology have aided the rapid conversion of the African surface market.

Jan 1, 2004

By N. Bartie

Realising the circular economy (CE) is faced with some significant challenges. Process metallurgy and its infrastructure play key roles at the heart of making the CE work. Therefore, the enabling role of process metallurgy within the CE will be central to the discussion in this paper, touching among others on product and system design as well as the key metallurgical and other process fundamentals that need to be investigated and understood to make the CE a reality. The central role of materials and its processing will be discussed in an integrated circular cities perspective. A key focus will be a discussion on designing a resilient “Smart Materials Grid” using and innovating metallurgical process engineering tools, which will manage the flows through Sustainable Circular Cities. The discussion will be using copper as leitmotiv of the discussion i.e. from copper ore, to metal, to complex products, recycling, product design and simulation and its impact. INTRODUCTION The transformation of our economies from linear to circular models in which waste materials become resources is the focus of the Circular Economy (CE) paradigm. Its important intentions: to take control of the damage we have been doing to the planet to ensure its livability and the welfare of future generations. This can only be achieved through careful utilisation of human, natural and economic resources. The concept is derived from several others (Beaulieu et al., 2015), of which Cradle-to-Cradle, Extended Producer Responsibility (EPR), Industrial Ecology, and Life Cycle Thinking are just a few. Other relevant concepts include resource efficiency (RE), design-for-recycling (DfR), and various others discussed by Blomsma and Brennan (2017) and Homrich et al. (2018), as well as various R-hierarchies e.g. Reduce, Reuse, Recycle (3R). However, does society comprehend these concepts, the actors and actions that influence them and how they interact? Do we know the limits of CE? Does society understand the key role of Copper and other metals to rendering the CE operable? True life cycle and systems thinking, focussed on simulation-based, process and metallurgical design are required to answer these questions. Lieder and Rashid (2016) identify nine widely-varying fields that study the concept ranging from sustainability sciences and engineering to economics, business, law, and social sciences. Overlap between questions addressed highlights the need for interdisciplinary collaboration (Nanz et al., 2017) in the assessment of the current status, and further steps needed to transform to CE. This doesn’t apply just in academia, but also in industry where concrete implementation of CE needs to occur at multiple levels, thus necessitating cooperation between government, civil society and other stakeholders (Beaulieu et al., 2015).

Jan 1, 2019

By Salim Mezazigh

Usually different methods for designing a single pile submitted to a lateral loading are available. They are based on theory of elasticity with the parameters E,v or subgrade reaction method using the p-y curves. The subgrade reaction methods are commonly used. They allow determining the efforts exerted along the piles and their corresponding displacements. Before any design the reaction curves P-y must be well defined for each foundation soil layer. These curves link the pile horizontal displacement y to the subgrade reaction of soil P. Different in situ tests such as the static penetrometer or the pressuremeter give a possibility to get the P-y curves in the case of a single pile installed in sand with an horizontal surface and statically laterally loaded. These ideal conditions are not always respected on the site around the pile if appear slopes, embankments, or buildings... The behaviour of such configurations of piles is more sophisticated due to the proximity ( slope, embankment, earthworks, buildings,..). A research program has been conducted to determine the influence of a slope on the P-y curves by centrifuge modelling. The centrifuge tests constitutes an experimental approach allowing parametric studies in respect with similitude laws in geotechnique. Before all, repeatable tests have demonstrated that the test conditions, the instrumentation equipment and the installation method for piles are well controlled. By this way, the obtained results from centrifuge tests can be transferred to the prototype i.e. the in situ piles. Many tests have been performed on piles in sand to determine the influence of a pile on the p-y curves. The main objective is to give for practice some coefficients to apply to p-y single pile curve to take into account the proximity slope effect. Here the experimental set up is described and in particular the proximity slope effect is discussed. Deduced subgrade reaction reduction factors are proposed for piles in sand under lateral loading.

Jan 1, 2002

By D. Hamilton

The electrode of a PEM fuel cell consists of two distinct sections - the catalyst layer and the porous transport layer (PTL). There are several kinds of PTL material, although all use carbon fibres as the solid fraction. The fibres can be matted to form a paper, woven into a cloth, or chopped to form a felt. Despite the different morphologies of the media, they are all anisotropic in structure, that is the majority of continuous fibres lie perpendicular to the direction of bulk transport. Currently, no models account for anisotropy and all transport coefficients are calculated as volume weighted averages or from empirical correlations (not developed for fibrous porous media). The present work presents a new methodology for determining anisotropic transport coefficients in fibrous porous media. A numerical experimentation process is employed wherein random samples of the PTL are generated and used to solve a diffusion transport equation. Effective transport coefficients are determined by integration of flux across the domain boundaries once a steady state solution has been reached. Multiple random samples at each porosity are generated in order to predict statistical variance. The results are correlated for ease of implementation in full PEM models.

Jan 1, 2005

By Herbert Hoover

This paper is in the nature of a rough preliminary report on the progress that has been made in the application of the mass spectrometer to various problems arising in the petroleum industry. A few years ago the authors considered a number of the problems that were arising in the qualitative and quantitative measurement of small amounts of hydrocarbons. The methods available of making analyses by chemical techniques appeared to leave much room for improvement. Without going into the reasons at this point, attention was turned to the possibility of employing physical instead of chemical methods of accomplish-ing the desired results. A preliminary investigation disclosed that the mass spectrometer presented a possibility of solving many problems which could not easily be accomplished by other methods. Work was begun in developing the necessary apparatus and technique. A great deal of encouragement and many valuable suggestions were received from Dr. Robert A. Millikan, Dr. W. R. Smythe, and Dr. W. N. Lacey, of the California Institute of Technology, and from Dr. E. 0. Lawrence, who recently received the Nobel Prize, of the University of California. The authors particularly wish to acknowl-edge the very great willingness of these out-standing scientists to be helpful in solving many of the problems that were involved. So far as the authors are aware, this was the first application of the mass spectrometer to commercial work. The results were considerably better than had at first been anticipated. Briefly, it is pos-sible to run a qualitative and quantitative analysis of an unknown mixture of hydro-carbon gases, with an accuracy of better than plus or minus 5 per cent of each of the various constituents. An exceedingly high degree of sensitivity has been obtained, and a relatively short time is required to com-plete an analysis. Furthermore, it is un-necessary to separate a mixture of gases into its various components in order to complete the analysis.

Jan 1, 1940

By Charles L. Kimbell

The series summarizing the prices of the major nonferrous metals on the stock exchanges of the United States and the United Kingdom has been continued this year in tables 23 and 24. As a result of the lack of availability of comprehensive data on the prices of metals in Canada, the table that had presented that information in past years in this chapter has been discontinued and the price series for nickel that had been in that table now appears in the table presenting metal prices in the United States.

Jan 1, 1993

By V. R. Degner

Development of large mechanical flotation machines during the past fifteen years. This success was a contributing factor in recognizing the value in a systematic and rational means of optimizing the flotation circuit, where the preferred circuit arrangement is based on both economic and metallurgical performance considerations applied to a relatively small number of flotation machines. Flotation kinetics and effective pulp residence time models have been incorporated into a computer program, described in this paper, which has proven to be an effective analytical tool to quantitatively relate flotation process parameters, such as feed tonnage and grade, solids concentration, and reagent strategy, to flotation circuit arrangement, machine size and operating condition.

Jan 1, 1993

MELTING in a hearth and in a basket is almost the same thing; charcoal and bellows are used for both. These are made large or small according to the quantity that you wish to melt, and more or less force of the bellows is applied according to the need. The hearth, bowl, or refinery, as the masters call it, is made with bricks and clay like a forge; opposite the middle of the tuyère a round hole is made like a wash- basin, wide at the mouth and narrow at the bottom where there is a hole for emptying it. A little iron plug is put in this so that it may be closed when necessary, or a piece of brick that is cut and pointed. Now, when this has been well covered all over with ashes, and the tuyère has been arranged so that the wind strikes the center, it is first filled with charcoal and baked very well so that the metal may be kept hot once it has been melted. When it has been baked, it is again filled with charcoal, fire is applied, and it is left to inflame gradually by itself. Then put one or

Jan 1, 1942

Table 1.-Salient statistics of carbon black produced from natural gas and liquid hydrocarbons in the United States [ ]

Jan 1, 1967

It is indeed an honour to address the perth branch of the australian institute of mining and metallurgy and to have the opportunity to talk to you about the future role of upgraded ilmenite on t102 feedstock supply and demand. There have been many papers written on upgraded ilmenite supply and demand and now I would like to share with you QIT's view of the situation first, a word about demand, although I will be talking principally on the supply issue. The principal use of t102 is in the manufacture of pigments which, in turn, are used in paints, plastics, and the paper industry together with a few miscellaneous uses, while a further b% or so of t102 minerals are consumed for the manufacture of titanium metal and for the manufacture of welding electrodes. the total demand for contained t102 is of the order-of 3 million tons per annum, and the general consensus in the industry is that growth rates should be of the order of 2% annually- it is against this backdrop that suppliers must compete with one another and produce least cost materials for the pigment industry. At the moment, supplies are relatively tight, but the generally slow growth in demand coupled with the abundance of titanium bearing minerals should ensure that long term the reverse is generally true. Now, let us examine the supply situation. Titanium is the 9th most abundant element in the earth's crust, so the problem from the producers` point of view is not one of scarcity of titanium minerals, but of how to extract most economically t102 feedstocks from a wide variety of choices- up to the present, all titanium feedstocks are being derived from either rutile or ilmenite rutile, at about 95% t102 content, is indeed a premier raw material which does suffer from potential scarcity and rutile supplies will likely be a diminishing factor in future decades- whereas ilmenite, a combination of iron and titanium oxides found in varying ratios, may be found in huge quantities all over the world.

Jan 1, 1986

By Bruno Miranda de Miranda

O Trabalho proposto demonstra os avanços dos resultados das grandes reformas de usinas de pelotização da empresa Samarco Mineração, unidade industrial de UBU, utilizando de forma sistêmica a metodologia de gerenciamento de projetos IPA (Independent Project Analysis). Através da metodologia obteve-se maior envolvimento e integração dos stakeholders e canais de processo com foco na segurança, saúde e meio ambiente. Outros fatores relevantes foram o aumento da utilização de recursos próprios, modificações de estratégia de contratação e análise crítica das paradas com aprendizado contínuo. Neste trabalho apresentaremos a definição do processo com fundamentação teórica e determinantes de excelência, incluindo os indicadores e resultados obtidos através do método, como indicadores de desenvolvimento abordamos os principais pilares da manutenção, sendo eles: segurança, custo, prazo, acurácia e produção.

Aug 7, 2018

By J. Price Wetherill

THE coal-seams that are worked vary from 32 to 100 feet in thickness, and occur at all angles of inclination, but are never flat for any great extent. They contain coal, slate, and an unsolidified coal, called dirt by the miners, in various proportions, a uniform seam of coal alone being rare. The upper walls are composed of conglomerate, sandstone, or slate; the first two hard and solid in texture, and withstanding the action of the atmosphere and moisture sufficiently well to offer but little trouble to the mining operations ; while the latter crumbles rapidly, owing, in part, to the decomposition of iron pyrites which it contains in large quantities, and in part to its own friable character, and requires constant care to avoid accidents to the men working below it, and to prevent its mixing with the coal mined. The floors are composed of slate. As in all mining operations, the. general system pursued is to reach with a permanent outlet such a point in the seam as will

Jan 1, 1877

By L. W. Davies

ONE of the most important applications of the zone-melting process of Pfann1 concerns the refining of materials with respect to impurities whose distribution coefficient k differs from unity. The repeated passage of molten zones along an ingot concentrates the impurities for which k < 1, for example, towards the end to which the zones move. It is desirable to know the ultimate distribution of impurity after the passage of an infinite number of zones of constant length; this is also the distribution which is unchanged by the passage of a further molten zone.

Jan 1, 1959

By A. E. M. Warner, P. J. Mackey

Copper metal is produced in large or small tonnages in almost all countries of the world—handling raw materials in the form of either as-mined or milled ores, custom concentrates, or other custom materials including scrap and recycled copper. The scale of operations and type of technologies used around the world varies widely. There is a certain concentration of both mining and smelter-refinery production as a total of ten countries produce some 80% of world mined copper, while ten countries—mostly different ones— produce about 80% of smelted and refined copper. As a result, international copper trade is significant. The present paper takes the reader on a virtual tour of the copper plants throughout the world with a focus on smelter facilities. Operations and technology employed at each plant visited are discussed including a brief historical sketch. Future trends identified during the world tour are also discussed. The present authors considered sufficient time was required for a thorough study tour and settled on eighty days—the same as that for the celebrated fictional story of world circumnavigation in the 1870s. INTRODUCTION The celebrated French writer Jules Verne published his book “Around the world in 80 days” in English in1873 and it is the story of Phileas Fogg and his French valet Passepartout circumnavigating the world in 80 days in the fall of 1872 on a £20,000 wager (equivalent to over 2 million pounds today) from the exclusive Reform club in London. This is an interesting period for copper as it started trading on the London metals Exchange in 1876 and the start of global copper production chains started to take off at this time with the rapidly increasing electrification of the world. The production chain includes mining, mineral processing, smelting, refining and fabrication. Since 1880 annual world copper production has increased by over 150 times from 154,000 tonnes in 1880 (nominally considered as smelted copper—essentially the only route at the time to marketable copper) to over 23 million tonnes today (including total refined copper of 19 million tonnes of smelted copper including scrap and 4 million tonnes by solvent extraction-electrowinning), in tandem with increased electricity usage, along with significant transportation usage and for manufactured products (Figure 1).

Jan 1, 2019

By B Lyne

In 1990, the Queensland mining industry had come to the conclusion that new safety and health legislation based on risk identification and control was required if the mining industry was to be effectively and efficiently regulated. In particular stakeholders in the coal mining industry had arrived at this opinion after the industry had suffered a number of major underground explosions over the 14-year period between 1972 and 1986. Also by 1990, a general consensus had emerged across both the coal and metalliferous mining sectors that mining industry was over regulated and, more to the point this over regulation did not encourage industry to identify and address the underlying causes that had led to a cycle of major mining accidents in the state. The prevailing opinion was that the prescriptive legislation left the ownership of risk management with the regulator and not with the mine operator. This paper discusses the background to the development of the Queensland Coal Mining Safety and Health Act 1999 and the Mining and Quarrying Safety and Health Act 1999 and the progress made in improving safety and health since the statutes came into force on the 16 March 2001. The paper discusses the issues that had to be addressed during the development of the legislation including the interaction with other legislation based on based on risk management principles that either overly or interface with the mining legislation. The effect the underground explosion at Moura No 2 in 1994 had on the final content of the new legislation is also considered. Health is often the neglected twin of safety and health legislation and the paper previews the health surveillance system being proposed in Queensland to ensure that health of mine and quarry workers is afforded the same priority as their safety. By increasing the structured management of occupational health problems in our mines there is an opportunity to make significant improvements in mine safety In conclusion the paper reviews the results to date since the introduction of the new mining safety and health legislation in Queensland on the 16 March 2001. Progress has been made and more is yet to be achieved

Jan 1, 2003

The mining of mineral sands in coastal aquifers is often constrained by other land use conflicts and inappropriate controls imposed through a lack of understanding of environmental interactions and processes. The recent experience with the Tea Gardens mining operation illustrates how increasing our knowledge and understanding leads to more effective management of environmental problems. As well as a source of heavy minerals, the Tea Gardens sand bed serves as a town water supply source. From past experience it was believed that mining could cause undesirable increases in dissolved iron concentrations in the aquifer, but the reasons and mechanisms for this phenomenon were not clear. A water monitoring program was therefore designed for the mining operation which was aimed at protecting the water supply borefield from any detremental effects. After one year the results of the monitoring program were assessed in the light of new knowledge and understanding of iron hydrochemistry. It was found that the existing program was not achieving some of its major aims, and was therefore modified to a more effective and cost efficient program.

Jan 1, 1988

By Neil R. Burns, Michael Doggett

Abstract - The Nanisivik mine offers a unique opportunity to examine the economics of a mining scenario from its original feasibility study through to closure. In the early 1970s, the Strathcona Sound project (exploration around the Nanisivik mine) had advanced to the point where a significant mineralized body had been defined and a feasibility study was initiated. The study supported development of the Nanisivik mine, with government investment in regional infrastructure, and the mine was constructed and operated for 26 years. Many elements of the feasibility study were difficult to estimate because the project was unique in its high Arctic setting. As a result, many differences were found when comparing the actual mining data to the feasibility study. The majority of these differences were the result of an actual mine life of 26 years instead of the planned 12.5 years. Most of the mining costs were higher than estimated and production occurred at a much higher extraction rate than planned. On a constant dollar basis, the metal prices were, on average, below the feasibility estimates. For the most part, these differences balanced out, with the actual mining being only slightly more profitable than anticipated in the feasibility study.

Jan 1, 2004

By E. W. Newman

DURING 1943 and 1944, there was an urgent need for certain grades of optical calcite (Iceland spar) for instruments for military uses. To find a supply of this material, prospecting was carried out in Montana, California and Colorado. Although some production was obtained by the work in California, the best results were from prospecting the large calcite veins of south central Montana. The bulk of the optical calcite mined during World War II has come from that area. The Bureau of Mines took an active part in the search for optical calcite in Montana. It examined most of the known calcite veins in the 70-mile distance between Wilsall, on the Shields River, and Absarokee, on the Stillwater River, and conducted exploration on several of the deposits. The Geological Survey also took an active part by mapping many of the veins. Actual mining of the calcite was performed at first by Calcite Operators, Inc., and later by the Metals Reserve Co., through an agent. A sorting plant was established at Clyde Park, where custom material could be sold. These activities stimulated mining by private operators. To be suitable for military uses, the calcite mined had to meet rigid specifications as to both size and quality. Individual crystals had to be clear and transparent and if in the form of rhombs had to measure at least 7/8 in. on each edge. Some color and a few inclusions in the calcite were allowable, but material with incipient or developed cleavages, or showing twinning other than parallel to the base, was unacceptable. HISTORY OF DEPOSITS The existence of large veins of calcite in south central Montana has long been known, and for many years the farmers of this region have used the common vein calcite for producing grit for chicken feed. According to reports, the first optical calcite produced from Montana came from the Cartwright deposit near Greycliff,1 but until recently the mining of optical calcite in Montana has been limited to spasmodic searching for small crystals suitable for making nicol prisms for saccharimeters and microscopes, or for mineral specimens. The possible need of substantial amounts of optical calcite for military uses began to appear late in 1942 and early in 1943, therefore the Polaroid company began searching for a source of supply in Montana and California. Work on the Wade property near Clyde Park was started on a small scale in the fall of 1942, by A. H. Hansen, of Clyde Park. During the winter and spring of 1943, a modest quantity of optical calcite was mined and shipped to the Polaroid Corporation, Cambridge, Mass. Most of this was produced from the "Hansen vug," which was found close to the surface. Early in the summer of 1943, mining on the Wade property was undertaken by Calcite Operators, Inc., a company organized for mining optical calcite from the Montana and California deposits. This com-

Jan 1, 1945