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By Elaine Cristina de Azevedo

Materiais poliméricos sofrem danos estruturais ao serem submetidos à radiação X. Estes danos podem causar reticulação, quebra de ligações entre outros danos. Em diversos serviços de radiodiagnostico e de radioterapia é utilizado placa de etileno vinil acetato, EVA, para auxiliar o posicionamento de pacientes crianças ate 2 anos em radiografias de tórax. O objetivo deste trabalho é verificar se este material é adequado para ser utilizado nestes serviços. Para tanto, amostras do material foram submetidas a dose de 25 kGy e avaliados por espectrometria de infra vermelho com transformada de Fourier, e a superfície por medidas de rugosidade e microscopia eletrônica de varredura. Os resultados indicam que o material apresenta degradação com dose de 5 kGy e aumento da rugosidade.

Aug 8, 2018

By E. Fidler

A recent headline in the Wall Street Journal declared, "trendy management schemes very often fail." Many of the management techniques addressed in the accompanying article are associated with quality management including reengineering, benchmarking, total quality management, and employee empowerment. The article made the point that executives, employees, and customers who are involved in such programs rate the effectiveness of these programs very low, and the programs often fail. Yet, we all know of companies that have made significant advances in their operations using these same quality management practices. Why do a few succeed while many fail? History has shown that the companies that successfully carry out quality management programs have two things in common: 1) Strong leadership committed to the success of the program. 2) A comprehensive plan for carrying out and maintaining the program. Stated another way -the reason many companies fail is the lack of committed leaders and inadequate planning. It is ironic that the title of the Wall Street Journal article is "The Best Laid Plans."

Jan 1, 1994

The Australasian Institute of Mining and Metallurgy (AusIMM) is a professional society for all those associated with the activities of the mineral industry. Differences of opinion exist within the membership of the AusIMM on the role it should play in the future as a professional society in a changing industry and world environment. This same dilemma is concerning other professional societies of which the author is a member. Some of the activities and priorities of the AusIMM are reviewed in order to clarify a frequently expressed opinion that it identifies with and supports industry at the expense of representing the interests of its individual members. By definition and by action this is certainly not the case and it is concluded that all activities whether seen to be industry or member orientated serve to benefit both. The AusIMM plays a most important role in integrating and promoting the interests of all sections of the mineral industry whether corporate or individual and the Presidential activities in education this year provide an excellent example of this.

Jan 1, 1997

By Jansen N

Production from the narrow, high grade silver-lead-zinc orebodies below 15 level commenced in mid 1985.Geological, mining research and recent mining experience determined that a mechanised drill, fire and muck cycle would be the most suitable method.Ground conditions are predicted to be worse than in other cut and fill (MICAF) areas at Isa Mine, owing to the increased depth, more variable dip of the orebodies and the increased effect of major geological structures.Mechanised ground support and tight filling techniques feature in controlling these expected adverse ground conditions.

Jan 1, 1985

By B. A. Massey

Sooner or later, we'll encounter a subordinate, peer, or boss that will test our management skills to the limit. The chances are good that our formal educations have not fully prepared us to effectively handle the situation, and through trial-by-fire, we have learned that the management of people is often as much an art as it is a science. Assertiveness - as opposed to agressiveness - is basically positive persuation. Assertive management techniques can help combine the art and science of managment to sell ideas, accomplish goals, direct the workforce, and generally promote the corporate - as well as our own - objectives

Jan 1, 1986

By H. Y. Sohn, Y. Mohassab, D. -Q. Fan, M. Elzohiery, A. Abdelghany

The Flash Ironmaking Technology being developed at the University of Utah is aimed at producing iron directly from iron oxide concentrate. In this technology, the concentrate is reduced by H2 and CO gas mixtures formed from the partial oxidation of natural gas in a flash reactor. Natural gas represents an economically and environmentally superior reductant/fuel for the flash ironmaking. The rate equations for the reduction kinetics by H2, CO and H2 + CO gas mixtures were determined in the temperature range 1150–1600 °C. These rate equations were applied to experimental results from a laboratory flash reactor using Computational Fluid Dynamics CFD simulation. A new mini-pilot reactor, which is capable of operating at 1150–1550 °C with a concentrate feeding rate of 2–5 kg/h, has been installed. Commissioning of the reactor with an emphasis on preheating of the reactor, production of reducing gas mixtures and the feeding and collection of iron ore concentrate and product particles has been completed.

Mar 1, 2017

By Hitch M.

Many mining wastes, especially those from the metal mining industry, have traditionally been treated as a matter of little or no value and in practice a cost burden. Some wastes, due to their reactivity characteristics, have emergent values that go beyond purely economic and into the environmentally beneficial realm. This paper discusses the changing paradigm of mine waste management. Such fundamental parameters such as cut off grade, and strip ratio, are positively impacted by the revaluation of waste rock material. Mine rock waste can now be seen as a commodity of value, similar to the underlying ore being mined and influences the economic performance of suitable projects. This valuable material can be used for industrial purposes including acid neutralization as well as the capture and long-term disposal of anthropogenic carbon dioxide. The Turnagain Nickel project, located in northern British Columbia serves as an example of how waste rock material can become an important matrix for carbon capture and sequestration and can benefit economically from it. By producing material that has emergent economic value as well as carbon capture and sequestration capabilities, the sequestration matrix producer is a beneficiary of new carbon credits that have a market value and is looked upon favourably by regulatory authorities and affected stakeholders.

Jan 1, 2010

By W. C. Phalen

SALT-MAKING PROCESSES THE production of salt in the United States divides itself at the outset into two distinct classes: (1) The mining of rock salt and its purification and separation into marketable sizes, and (2) the production of salt by evaporation from brines, bitterns, and other solutions. The processes employed at the present time in the manufacture of salt by evaporation may be outlined as follows: 1. Solar evaporation. 2. Direct-heat evaporation (a) in open kettles; (b) in open pans. 3. Steam evaporation, (a) in jacketed kettles, (b) in grainers. 4. Vacuum-pan evaporation. In this paper only the solar-evaporation processes practised in different parts of the United States will be described. SOLAR EVAPORATION Localities In the Eastern States the solar-evaporation process is not generally employed for climatic reasons. In the Western States, particularly in California and Utah, the great bulk of the salt produced originates in the solar-evaporation process. Of the Eastern States producing salt, this process, so far as the writer is aware, is employed in New York State only.

Jan 9, 1914

By D. Tolgyesi, L. P. Gignac

Mine development has evolved in the past 15 years from a human-paced system using hand-held drills and track-bound equipment to a mechanized system using specialized equipment for each component of the development cycle. In most Canadian hard-rock mines, face advance is achieved by the following sequential activities: drilling, explosive loading, mucking and ground support. The state-of-the-art for each work element is reviewed and methods for performance estimates proposed. The entire development system and its production capabilities are considered based on equipment reliabilities, spare units, haulage distances, and muck bay spacing. The effect of the number of working faces on the system's performance will also be analyzed. Manuscript not received in time for publication.

Jan 1, 1983

By E. R. Phelps

It is very seldom that a completely new project is initiated. Most projects consist of a new and different combination of proven techniques or a combination of proven and new techniques. The theme of my discussion today falls in the second category. Proven methods of water transportation and proven methods of bulk material handling were combined with some new techniques which resulted in a new market for the coal industry and a cheaper fuel supply for the power industry. In this respect I refer to the water transportation of coal from the West Kentucky coal fields to coal burning power plants on the west coast of Florida. Peabody Coal Company, Florida Power Company, Gulf Coast Transit, and Mid-South Towing combined their individual requirements and "know how' to make this project possible. I feel the results speak for themselves since it proves that coal can be mined in the West Kentucky coal fields, transported some 1,200 miles by river barge and some 450 miles by ocean going barges, be delivered to power plants on the west coast of Florida and still meet the competitive prices of gas and residual oil. The unique parts of this project concerns the storage and trans loading facilities for coal from river equipment to ocean equipment near New Orleans; the return haul of phosphate and it's trans loading from ocean to river equipment at the same facility and the use of large ocean going barges. In detail it works as follows: Coal is mined in West Kentucky and loaded into 1,500 ton river barges on the Green River. It is then transported some 100 miles to the mouth of the Green on the Ohio River, then 200 miles down the Ohio to it's convergence with the Mississippi, and then 900 miles down the Mississippi to the trans loading facility some 40 miles South of New Orleans. There it is transferred from the 1,500 ton river barges to 18,000 ton ocean going barges and hauled some 450 miles across the Gulf of Mexico to the Gannon Station of Tampa Electric at Tampa entailing a total haul of approximately 1,650 miles.

Jan 1, 1966

By David L. Giles

The Lime Creek* ore body in northwestern British Columbia is one of the few commercial primary stockwork-type molybdenite deposits in North America. Others include the Climax, Urad-Henderson, Questa, and Endako ore bodies. They are mined on a low grade-high tonnage basis, and are open pit operations except for Climax and Urad-Henderson. Much recent geochemical research on both porphyry copper and stockwork MoS2 deposits has been concerned with dating of micas related to the mineralization and associated igneous rocks. The results appear to show that mineralization and the predominant magmatic events of the deposit are indistinguishable in age (1-5), except where dating has been in sufficient detail to resolve the analytical overlap (6). At Lime Creek, geologic information shows that the Main granodiorite, the major intrusive and dominant host rock for MoS2 mineralization, was emplaced and had solidified sometime prior to the introduction of MoS2. The first MoS2 episode is intimately related to localized bodies of kalialaskite which clearly intrude the older stock. K-Ar dating was undertaken to clarify the age relations between Lime Creek plutonism and the apparently younger hydrothermal event that began with kalialaskite.

Jan 1, 1975

By J M. Galvin

History attests to the catastrophic consequences that fire, explosion and contaminated, noxious andirrespirable atmospheres can have for workplace health and safety in underground coal mining. It also confirms that fires and explosions present the greatest risk of partial or total loss of underground mines and equipment and that this risk continues to materialise. The design, implementation, operation and maintenance of the mine ventilation system are core controls for managing the hazards associated with these risks, both for preventing them from materialising and for mitigating their consequences if they do materialise. These are most effective when embedded in a risk management approach.

Oct 12, 2022

By A Cheatle

GoldcorpÆs Musselwhite mine in north-western Ontario, Canada has in recent years become a world-class deposit. Initially discovered in the early 1960s by Alan and Harold Musselwhite, the then marginal mine eventually started production in 1997 and has to date produced 2.6 Moz of gold. Two million ounces of gold are currently classified as Mineral Reserve and a further 1.2 Moz of gold are classified in the Mineral Resource category for a total gold inventory approaching 6 Moz. Growth of the mineral inventory has been achieved through the successful implementation of strategic planning that sought to extend the mine life through discovery of additional economic zones and increased mined tonnages. Accelerated exploration activity commenced in 2001, at a time when gold price was at its lowest in decades. Focus was placed on building, developing and retaining a highly skilled geological team, maintaining purpose, conducting external reviews and developing a new geological model through research partnerships. Ongoing collaborative research between Lakehead University and Musselwhite mine has seen the development of new structural and geological models through post-graduate and academic studies. Research has included lithogeochemical, stable isotope and structural and metamorphic studies and has led to the evolution of a new mineralisation model (for the mine) and the recognition of brittle and ductile deformation regimes within the mineralised horizons. Exploration drilling continues to provide support for the new geologic model. Gold discoveries have extended known mineralisation 2.3 km along strike from mineral reserves and laterally into parallel zones. The exploration potential to further increase production rates, Mineral Reserves and Resources remains very positive and increases in overall gold inventory are likely. Musselwhite mine has significantly exceeded initial projections for a ten year life-of-mine and a marginal existence.

Jan 1, 2009

By George A. Miller

AMERICANS like engines, but more than anything they like powerful engines, and next to that they want them quiet, silent, smooth; perhaps a slight purr might be permitted, but they must not knock. To provide a gasoline to fit all these requirements, American petroleum technologists have experimented for years, and mounting octane numbers of the gasolines the refiners have produced both before and during the war bear witness to their success. The question on everyone's mind now is what may we expect in the way of engine fuel in the postwar period? The gasoline drouth during the war rationing, the inconvenience of doing without a car were major annoyances to all motorists, but they put up with them pretty cheerfully for the most part. However, now that the war is over, and the jalopies are all out and the better cars have been taken off the jacks and brought out on the road, the call is for "Some of that good gas-fill her up, if you please."

Jan 1, 1945

By Linda D. Raedeke

The main platinum-group metal (PGM) deposit in the Stillwater Complex is associated with a stratiform zone formed by magma mixing. In general, the intrusion is a large, layered body of Archean age which formed by repeated magmatic injections in- to a single, large, hypabyssal magma chamber. The Complex is broadly divided into the lower Ultramafic series of olivine ± orthopyroxene rocks (1000-2000 m thick) and the upper Banded series of predominantly plagioclase-rich rocks (24500 m thick). The latter is further divided into Lower, Middle, and Up- per Banded zones. The Ultramafic series, plus most of the Lower and Upper Banded zones formed from repeated injections of an olivine-saturated magma, the rocks accumulating from the floor upward with a crystallization order of olivine, or- thopyroxene, plagioclase, clinopyroxene. The olivine-bearing subzones of the Middle Banded zone formed predominantly from a magma which crystallized in the sequence plagioclase, olivine, clinopyroxene. Olivine-bearing subzone I, with which the PGM mineralization is associated, occurs generally -400 m above the Ultramafic series-Banded series contact. Ore grade mineralization is usually found in plagioclase or plagioclase-olivine cumulates. The platinum-group elements are associated with disseminated base-metal sulfides dominated by the assemblage, pyrrhotite-chalcopyrite-pentlandite. Olivine-bearing subzone I marks an interruption in the crystallization sequence of the Lower Banded zone, with the reappearance of cumulus olivine and an associated change of the crystallization sequence. These changes indicate the addition and mixing of a secondary magma of the same composition as that which later dominated in the formation of the Middle Banded zone. Characteristics associated with mixing include laterally discontinuous but well-developed layers, xenoliths of ultramafic rocks, and sedimentary-type structures such as slum- ping and graded layering. The influx of new magma caused sulfide saturation by one or more of several chemical changes including addition of sulfur, decrease in oxygen fugacity, decrease in FeO, or increase in SiO2. Once an immiscible sulfide liquid was formed, platinum-group elements were scavenged from the magma by the sulfide liquid and segregated.

Jan 1, 2013

By R. R. Sayers

There is probably no industry , trade , or art in which mercury is used but what has produced some cases of mercury poisoning . This is true of the mining and smelting of mercury , where the hazard has long been recognized . When the ore contains free mercury or the more soluble salts , and when the workings are underground and are poorly ventilated , cases occur , but there are a far greater number of cases among the employees about the reduction works . 3 In 1863 William V. Wells visited the mines at Almaden , * Spain , which were worked by convicts . He reported that the men at the furnaces suffered severely , being able to work only about one week out of four , when it was necessary to transfer them to places where the exposure was less . He states that "pale cadaverous faces and leaden eyes are consequences of even these short periods . " Mercury , like lead , when absorbed in small amounts at intervals , as daily, over an extended period of time will result in symptoms of poisoning . This is due to the fact that the mercury is eliminated from the body more slowly than it is absorbed . The frequency and severity of cases of mercury poisoning are far less with modern methods of mining and recovery of the metal than formerly . However , further reduction is possible and much can be done by both the workmen and the operators by following the proper precautionary measures , some of which are described in this chapter .

May 1, 1922

By N Lefebvre, M Jakeman, R Aseervatham

Semi-arid regions suffer from two afflictions; evaporation may exceed precipitation by multiples of two or more and variations in precipitation can be both extreme and difficult to predict. Many Australian mines are situated in semi-arid areas where communities are reliant upon locally sourced water or special purpose infrastructure is built as part of the mine construction. As the question of climate change looms, issues related to future water supply and sustainable water management become increasingly important. Across Australia several mining operations co-exist in a single surface water and/or groundwater catchment area. The management of water on a mine by mine or a community by community basis is illogical and must be reconsidered based on a single water catchment and a whole-of-community basis. Mine water should be considered on a full life cycle basis where the quality is assessed for specific mine site applications. This paper addresses technical challenges that include surface water and groundwater supply in semi-arid regions, operational water in the mining industry, beneficial uses of water, water economics and demand management. In much the same way as emissions trading evolved into a multi-stakeholder forum, mining regions offer scope for innovative thinking in water supply and reuse. In addition, this paper considers a number of initiatives taken by Australian mining companies that are entering a prefeasibility stage and contrasts these initiatives against the established success within a South African mining region. The challenges and potential solutions to this initiative are presented for future consideration.

Jan 1, 2006

By W. B. Paton

Introduction For several reasons the accident history of Flin Flon has been quite unlike that of any other mine in northern Canada, and very much unlike that of the average American metal mine. Towards the end of 1928, the mining project that is now Flin Flon, and that is now in the very: forefront of Canada's big producers was launched; but, metaphorically, it was launched in a tempest of mining troubles. Each branch of the mammoth enterprise was beset with extraordinary difficulties, and the Safety Department had its relative share. Difficulties in Accident Prevention The unusually rugged contour of the plant site made roads, and even moderately safe pathways, out of the immediate question. The project established an industrial outlet for depression-stricken areas which hitherto had been essentially agricultural; but through that outlet poured labour whose working atmosphere had been the bald prairie, labour that knew nothing of safety consciousness, labour that had to be moulded to industrialism, labour in the raw. A considerable length of the ore-body lay under the eastern section of Flin Flon lake. Open-pit methods were adopted to work the upper limits of the ore-body, and consequently the eastern section of the lake had to be dammed and pumped dry. The subsequent difficulties and hazards created by silt deposit cannot be fully visualized. And, finally, there was a geographical hindrance: the ore-body was partly in the Province of Manitoba and partly in the Province of Saskatchewan. The workmen's compensation problem became intricate. Insofar as accident prevention is concerned, Flin Flon's young industrial life may be conveniently divided into three distinct periods, namely: (a) Construction (Nov. 1928-June 1930) (b) Tuning up, and production till the strike (June 1930-June 1934) (c) Production from the strike till the present time At the peak of construction, due to the usual labour fluctuations of big jobs, there was a weekly turnover of about a hundred men. A very large percentage were Central Europeans, most of whom could neither read nor write English. Consequently, an organized safety programme was out of the question.

Jan 1, 1935

By Fabiana da Silva Santos

O presente estudo fez uso de uma liga de NiTi, rica em Ni, elaborada em um forno de fusão por indução a vácuo - VIM e posteriormente refundida em fornos de arco elétrico com eletrodo não consumível de tungstênio – VAR. Com base nos resultados de Calorimetria Diferencial de Varredura (DSC), Difração de Raios-X (DRX) e Microscopia Eletrônica de Varredura (MEV) / Espectroscopia de Energia Dispersiva de Raios-X (EDS), foi possível observar a heterogeneidade composicional/ típica de fundido por processo convencionais, as inclusões de TiC e Ti4Ni2O provenientes da fusão no forno VIM, e o refinamento microestrutural e manutenção da sua composição original com uso de cadinho de cobre e câmara/atmosfera dos fornos VAR.

Oct 30, 2017

By Alton G. Woody

Like so many installations of its type approaching middle age, the ore processing and shipping facilities in Puerto Ordaz, Venezuela, have taken a lot of twists and turns in their lifetime. The object of this paper is to lead you through these twists and turns and some of the reasoning for them. The need for additional sources of iron are in the United States became evident during the time of the second world war. An exploration team from U. S. Steel located further high quality direct shipping iron are in commercial quantities near Ciudad Bolivar, Venezuela in 1947. Basic decisions were made to develop these reserves for export via the Orinoco River through a new shipping port to be built at the confluence of the Orinoco and Caroni Rivers. The basic concept was for the ore to be loaded directly to ocean going vessels. This was something of a gamble since the basic economics depended upon successfully opening up the main channel of the Orinoco River to deepwater vessels, and the Bethlehem Steel mine in the same area was already working with shallow draft river boats and a transfer station on the coast. Always, the basic philosophy has tended to be to plan with expansion in mind. The original conveyor systems were 1.52 m (60 inches) wide with 200 idlers, whereas 1.07 m (42 inches) or 1.22 m (48 inches) wide conveyors could have carried any production foreseen at the time of installation. Stockpiles have been located and designed with room for expansion. Basic designs have had dotted line future expansion blocked in.

Jan 1, 1978