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By Darryl Lovato, Ramiro Pereyra, Daniel S. Schwartz

"During an annual inventory of nuclear material, a plated steel container which contained plutonium oxide failed. The container had been packaged for temporary storage but had been overlooked and remained in storage for more than 23 years. Although it was determined that the failure occurred through the slip-top rim, a metallurgical evaluation was requested to help to determine the integrity of the container.Optical metallography and scanning electron microscopy were used to analyze the character and degree of corrosion in the container. The depth of corrosion, measured at approximately 10 µm, did not pose a threat to the integrity of the container. However, the corrosion morphology and chemistry did suggest that a galvanic cell had developed between the tin and steel from the condensation of water. The morphology also suggests that the attack of the steel took place over a series of cycles due to changes of the environment.IntroductionMetallographic analysis was requested as part of the investigation into the mechanism of the failure of a slip-top container (#38621) containing plutonium oxide (PuO2) powder. The container had leaked during a special nuclear material (SNM) annual inventory causing contamination and closure of the vault. A photograph of the container and interior container is shown on the right in Figure 1. An initial investigation established that the source of contamination was the consequence of the failure of multiple layers of containment. Initially by the deterioration of the interior plastic bottle and polyvinyl chloride (PVC) bagout bag, and finally through the lid and steel container interface at a location where tape had not adhered properly [1]. Although the source of the breach was established, it was determined that metallographic analysis was important to establish the extent of deterioration of the steel container."

Jan 1, 2008

By Juan Sánchez

En la actualidad, los problemas que la sílice genera en la operación de planta de extracción por solventes (SX) de cobre están bien abordados. Comúnmente, la sílice (SiO2) en forma de sólidos suspendidos es la que tiene mayor ocurrencia y por lo tanto sus repercusiones mejor tomadas, sin embargo, la ocurrencia de sílice en forma de coloide es un problema que, aun agendado, en muchos casos genera tal variabilidad operacional, acarreando problemas de control de la operación llegando incluso a la detención completa de la operación debido a la emulsión de las fase orgánica y acuosa y los correspondientes costos asociados.

Sep 29, 2023

By I. G. Gonçalves

For most industrial minerals, the color is directly associated with economic value. In terms of physics, the principal property that defines the term ?color? is the intensity of light reflected (or transmitted) by an object over the visible band, comprehended between 400 and 700 nm. This reflectance spectrum serves as the starting point for a variety of color-describing factors, the most common in the mineral industry being the brightness (TAPPI, 1977 and 1986) and the L*a*b* system (HunterLab, 2008). Quality specifications for mineral products are usually based on these colorimetric parameters. This market is becoming increasingly more selective and demanding over the quality of raw materials and alongside the traditionally controlled characteristics, such as particle size distribution and chemical composition, a trend exists towards the establishment of increasingly more strict specifications for the optical properties of these materials. This is due to the fact that most plants consuming these industrial minerals incorporate them into products in which the visual appearance is controlled. For these plants, most of them being the manufacturers of plastics, paper, paints, and ceramics, variations in the color of mineral materials result in difficulties to achieve the right color in the final product. Therefore, these plants set strict specifications for colorimetric parameters such as whiteness and yellowness, as well as colorimetric coordinates like L*, a*, and b*. For the manufacturer of industrial minerals, this translates into difficulties simply because many of these parameters are usually alien to the tradition of the mining industry. The main quality parameter in the kaolin industry is brightness, which is a weighted average of reflectance values over the range of 400-510 nm (TAPPI, 1977). Due to the lack of a better property, producers tend to use brightness to also assess the quality of the in situ ore and along the processing operations. However, the unprocessed kaolin is often accompanied by ?contaminant? minerals. For Brazilian kaolins, which are the object of this study, the most important contaminants are hematite (Fe2O3), goethite (FeOOH), and anatase (TiO2). Each of these contaminant minerals has a distinct color and behaves differently during the processing of the kaolin ore. Hematite and goethite in particular are particularly strong pigmenting agents and at concentrations as low as 100 ppm they can make the difference between a high-quality white pigment product for paper coating and waste material. As each Fe-bearing contaminant has a different color and responds differently to processing operations (for example, magnetic separation, chemical bleaching, selective flocculation, and/or flotation in the case of kaolin), the in situ brightness tends to show a poor correlation with the brightness of the final product. Brightness measurements are sometimes complemented with X-Ray Fluorescence (XRF) analysis of Fe and Ti, but the total oxide content provided by XRF is also poorly correlated with product quality because Fe may be in the form of goethite, hematite, or inside the crystalline structure of kaolinite. Thus, a more robust technique capable of distinguishing each mineral phase is desirable. Diffuse reflectance spectroscopy has been used to analyze iron oxide/hydroxide content both qualitatively (Torrent and Barrón, 2003; Liu et al., 2011) and quantitatively (Jiet al., 2002 and 2006). These authors correlate slopes and inflection points at characteristic absorption bands with oxide/hydroxide content in natural soils. The approach presented here involves the extensive use of the Kubelka-Munk (K-M) theory, which has been used for color matching (Schabbachet al., 2009 and 2011) and particle size determination (Otsuka, 2004) in a simplified version. Unfortunately, the scattering constant S is very difficult to measure for dry powders, because the equations require a thin layer of material. Attempts have been made (Gonçalves and Petter, 2007, and Gonçalves, 2009) but the experimental errors tend to be high. Thus, this paper aims to develop a tool for the quantification of contaminant minerals in kaolin based on the K-M theory without resorting to measurements over thin layers. This tool is based on a new two-constant approach, which takes into account differences in scattering between materials over the whole measured spectrum. The experimental dataset consists of the reflectance spectra of mixtures between a bleached kaolin and synthetic Fe pigments.

Feb 27, 2013

By Aysan Molaei, Kristian E. Waters

"Solvent extraction is the one of the most common techniques for recovering metal ions from aqueous systems. However, it is not efficient in the extraction of low concentration metal ions from aqueous solutions. Predispersed solvent extraction (PDSE) is an alternative method for solvent extraction which implies colloidal liquid aphrons as extracting agents in order to reach higher interfacial area and lower reagent consumption. This work investigated important parameters in PDSE of nickel ions from dilute aqueous solutions by fractional factorial design of experiments. Four experimental parameters, the initial extractant concentration, initial surfactant concentration, equilibrium pH and phase volume ratio (organic to aqueous ratio) were investigated. The important parameters were determined as well as important interactions between these parameters. It was found that extractant concentration, phase volume ratio, and equilibrium pH are the most significant experimental parameters. However, the interaction between surfactant concentration and other parameters was determined as significant interactions.INTRODUCTIONNickel is one of the key components found in cars, mobile phones, rechargeable batteries, kitchen appliances, and steel industry (Anyadike, 2002). It is one of the most important metals produced by Canada which is in the five top nickel producers in the world. Despite a 24% decrease in the nickel prices from 2011 to 2014 the nickel global mine production increased by 36% between these years (U.S. Geological Survey, 2015; Nickel - Statista Dossier, 2015), which shows the increasing demand for nickel. This high demand leads producers to consider the production of nickel from low grade ores and other secondary sources such as process wastewaters. The removal of nickel ions from process wastewater is also important due to environmental considerations. Nickel is known to be a human carcinogen and it may cause serious lung and kidney problems, pulmonary fibrosis, gastrointestinal distress, and skin dermatitis if it exceeds the critical level (Borba et al., 2006; Fu & Wang, 2011)."

Jan 1, 2016

By J. J. Brummer

The possibility of diamonds occurring in Canada was first raised by W. H. Hobbs in 1899, who concluded: "that the apex of the fan of diamond distribution probably lies somewhere in the strip of the territory bordering James Bay on the east." This was based on the occurrence of diamonds in surficial sediments at various locations south of the Great Lakes. There are two recorded discoveries of drift diamonds in Ontario: (a) the Peterborough Diamond, 33 carats in size, poorly documented and found sometime before 1920;and (b) the Jarvi Diamond, 0.255 carat, found during 1971 in Sheraton Township near Timmins . Both discoveries were in surficial sediments and their source(s) have not been located. During 1960, Selco Exploration Company Ltd. started a heavy-mineral sample program of river gravels in the James Bay Lowlands of Ontario. This was continued by Canadian Rock Company Ltd. (1962-1963) and the Ontario Division of Mines (1973). The surveys discovered the presence of kimberlite minerals in gravel samples from streams draining the Moose River Basin. A total of 53 pyrope grains, four magnesian ilmenites and one grain of chrome diopside were identified from 32 sample locations. A study of the distribution of these minerals suggested the kimberlite source rocks to be located along the north margin or within the Kapuskasing gravity "high" in the area immediately south of James Bay. The Jarvi Diamond, found on an esker east of Timmins, could well have originated from this area. During 1965, an esker was sampled by the Geological Survey of Canada, and the results attracted attention to the area south of Lake Abitibi. At 9 out of 34 sites sampled along the Munro esker, Lee recorded the presence of pyrope garnets and very minor chrome diopside.

Jan 1, 1978

By Lulie H. Crump

Salient information on reserves, production, and consumption of fuels and energy by State are summarized in this Bureau of Mines publication. The data are broken down by fossil fuels (coal, petroleum, and natural gas) and hydropower and nuclear for the major consuming sectors: Household-Commercial, Industrial, Transportation, Electric Power and Miscellaneous. In addition, total energy consumption in the Nation in 1972 is compared with consumption in 1971 and 1973 (preliminary data).

Jan 1, 1974

By G. Van Weert

Separation of minerals by shape has received little attention, since minerals normally do not break into different shapes during crushing and grinding. However, comminution of consumer wastes generates opportunities for novel separations based on particle shape. For instance, ductile plastics are broken into longer curved shapes, whereas brittle plastics yield angular particles. Using spouting beds for particle separation in water requires controlling the spout's instability. The preferred geometry for such redesigned spouting beds is reported. Plastic cylinders, discs and spheres were separated as a function of rising water velocity and amount of particles in the system. By using 5 mm particles, differences in settling behavior could be video recorded.

Jan 1, 1999

By Bailey, Lewis Newton

Bailey, Lewis Newton, Master Engineer, Senior Oracle, 4th Regiment, U. S. Engineers, Headquarters Company, died of pneumonia, at Camp Merritt, N. J., on April 30, 1918. Baird, Louis, Lieut., Royal Field Artillery, British Army, died on the battlefield in 1915. Ballamy, John H., Capt., 103d Engineers, killed in action near Fismes, Aug. 9, 1918. Burt, Andrew, died in active service, 1916. Cobeldick, William Morley, Royal Engineers, died from gas poisoning on October 7, 1915. Dougall, Ralph, 4th University Co., Princess Patricia Regiment, killed in action early in the war. Evans, Alfred Winter, Lieut.-Col., New Zealand Rifle Brigade, D. S. 0., D. C. M. killed in action on October 12, 1917. Gorman, Thomas C., Lieut., Canadian Engineers, killed in France, Mar. 18, 1918. Hague, William, 1st Lieut., Engineer Officers' Reserve Corps, died in active service, Jan. 1,, 1918. Hall, William T., Capt., Royal Flying Corps, killed in action, May 19, 1917.

Jan 11, 1918

By Donald Ingvoldstad, Harold E. Lee

At Bunker Hill the original charge storage and preparation system was installed in 1917 to accommodate lead-silver gravity mill products. Only minor tonnages of wet fines such as vanner and flotation concentrates were received. Charge flux and diluent requirements were provided by an ample supply of siderite middlings and coarse limerock. While oversize material was crushed through Y4-in., the use of roll crushers in series resulted in a more or less granular, free-running charge of adequate porosity. Under such conditions, receipts could be proportioned directly from receiving bins, and suitable blending was obtained by passing the resultant layered composite through a small Stedman disintegrator. This elementary system served well for production and smelting of an extremely lead-rich sinter, in the low column blast furnace. Here sinter physical quality is less critical, and appreciable quantities of raw flux and oxidized ore may be charged directly to the blast furnace without seriously impairing furnace capacity.

Oct 1, 1956

By John F. Papp

Based on a review of historical domestic and international chromium metal production capacity, production, consumption, trade, and trade literature, world annual chromium metal production capacity in 1995 was estimated to have been 38,300 metric tons, a drop from 43,500 tons in 1994. World chromium metal production and consumption were estimated, on average from 1984 through 1992, to have been 21,000 tons per year. U.S. consumption was estimated, on average over the same time period, to have been 6,200 tons per year. The major world chromium metal producers between 1984 and 1995 were China, France, Germany, Japan, Russia, United Kingdom, and United States. From 1984 through 1992, world trade averaged 8,400 tons per year. Germany and the United States accounted for over 75 percent of imports on average during the same time period. U.S. chromium metal import value rose from under $1 per kg before 1964 to over $6 per kg in 1993. Over the same time period, prices rose from about $4 per kg to about $10 per kg. Chemical specifications have become more stringent. Detailed chromium metal trade, prices, value, chromium metal chemical specification, and production capacity by country are reported. A shift in trade patterns was anticipated as Japan exits production and displaces Germany as the second largest importer and as Russia increases its role in world trade.

Jan 1, 1995

By R. F. Stewart

A sedimentation method involving the use of the Palo-Travis apparatus was found satisfactory for rapid determination of the size distribution of coal particles ranging from 10 microns in diameter to those passing an 840-micron opening (20-mesh sieve), The method is most useful for comparing the size distributions of samples of pulverized coal where the actual size of the particles is not required and is applicable to sieve and subsieve sizes of a wide variety of coals and chars that can be wetted and are heavier than water. An analysis, including all calculations, can be completed in 1/2 to 10 hours, depending on the time required for the finely divided coal to settle. A typical analysis requires about an hour, making this a rapid, precise method for routine size-distribution analysis of powdered coals. When used with coal particles smaller than 400 microns, the method is precise within 15 microns for wide variations in test conditions and within 5 microns for identical test conditions. The precision decreases as particle size increases, becoming unsatisfactory for particles larger than 400 microns (40-mesh). For precision within 15 microns, the samples must be equal in weight. Greater precision is obtained with 4-gram samples, but samples as small as l gram may be used.

Jan 1, 1961

By M. Ye. Melnikov

The report is about oceanic ferromanganese crusts ? covers of iron and manganese hydroxides developed over an opened rock of seamounts and rises. Ore bed parameters of crusts are understandable as their thickness and content of main economic components ? manganese, cobalt and nickel. All known results of research activity on ferromanganese manganese crusts point to that crust are characterized by notable variability of thicknesses and composition. It is possible to separate few levels of variability. The most evident is the first level of parameters variability, which is manifested in various regions of the Ocean, and connected first of all, with an age of submarine mountains, a host objects for a crusts. It was proved by many authors, that most powerful crusts are connected with submarine mountains of Cretaceous age. [1]. Crust thickness at the Magellan Seamounts reaches, for example 12-15 cm, sometimes exceeds 20-22 cm. Thicknesses of Hawaii Archipelago or Tuamotu crusts in 3-4 times less. Biostratigraphy studies of crustal sections at the Magellan Seamounts already show, that its main part started to form in the Late Paleocene. Four layers with well expressed features in structure and composition of a layer are separated in the section. From foot to top: Late Paleocene ? Early Eocene layer I-1, Middle-Late-Eocene layer I-2, Miocene layer II and Pliocene ? Quaternary layer III. Relics of more ancient Campanian ? Maastrichtian ore layer [2, 4] were discovered. It is evident for example, that Oligocene mountains could not be a host for two lower layers in the crust section.

Jan 1, 2010

By M. Ye. Melnikov

The report is about oceanic ferromanganese crusts ? covers of iron and manganese hydroxides developed over an opened rock of seamounts and rises. Ore bed parameters of crusts are understandable as their thickness and content of main economic components ? manganese, cobalt and nickel. All known results of research activity on ferromanganese manganese crusts point to that crust are characterized by notable variability of thicknesses and composition. It is possible to separate few levels of variability. The most evident is the first level of parameters variability, which is manifested in various regions of the Ocean, and connected first of all, with an age of submarine mountains, a host objects for a crusts. It was proved by many authors, that most powerful crusts are connected with submarine mountains of Cretaceous age. [1]. Crust thickness at the Magellan Seamounts reaches, for example 12-15 cm, sometimes exceeds 20-22 cm. Thicknesses of Hawaii Archipelago or Tuamotu crusts in 3-4 times less. Biostratigraphy studies of crustal sections at the Magellan Seamounts already show, that its main part started to form in the Late Paleocene. Four layers with well expressed features in structure and composition of a layer are separated in the section. From foot to top: Late Paleocene ? Early Eocene layer I-1, Middle-Late-Eocene layer I-2, Miocene layer II and Pliocene ? Quaternary layer III. Relics of more ancient Campanian ? Maastrichtian ore layer [2, 4] were discovered. It is evident for example, that Oligocene mountains could not be a host for two lower layers in the crust section.

Jan 1, 2010

By Alejandro Freyre B.

"El presente texto señala el proceso de explotación de la veta Shiusha situada en el distrito de las minas de Huarón. La veta es de origen hidrotermal, cuyo rumbo aproximado es E-W, y su buzamiento varía de 75º N en el Estea 85º N al Oeste, uniformizándose en los niveles inferiores en 85º :N. El eje mayor probable del depósito ( plano Nº. 1 '), tiene una inclinación de 25 º E. El depósito se extiende sobre una longitud de 1100 m, entrelas coordenadas 4600 - 57 00 E., pero la calidad y cantidad del mineral son variables en las tres dimensiones. Asimismo, se describe la prospección, preparación para corte y relleno, arranque, intermedias de los tres compartimientos y la aplicación de gradines descendentes vacíos."

Aug 20, 1963

By Loyslene Rabelo Fernandes

Esse trabalho experimental apresenta os resultados preliminares da lixiviação de placas de circuito eletrônico de microcomputadores sucatados visando a extração de cobre, além da recuperação daquelas espécies através de precipitação por neutralização do licor de lixiviação. As placas foram desmontadas, fragmentadas em pedaços menores, onde passaram por uma incineração no forno mufla, moídas por moagem manual, onde depois sofreram ataque com ácido clorídrico e ácido sulfúrico. Também houve o processo de eletrodeposição com as laminas de cobre encontradas na moagem manual, onde apresentou 14% de cobre depositado.

Oct 30, 2017

By P. R. Jones

The Bureau of Mines has written a computer program for the design and cost of a shell and tube type heat exchanger, in which a change in phase occurs on the shell side. The total cost, which was minimized, includes the annual fixed charges and annual operating costs. The program was written to meet the following requirements: (1) Triangular pitch, (2) single or multiple pass, and (3) heating or cooling. Price optimum design was obtained for four standard tube diameters and pitch. Standard heat exchangers whose area equaled or exceeded the required area are also listed. The program was made adaptable to various fluids and to various tube dimensions by including many of the required data such as physical properties of the fluids, tube data, and standard shell data as input data.

Jan 1, 1969

By Brandon M. Robinson, Osman F. Besler, Dominik Gaechter

With the increase in population over the last decade, and anticipated population growth over the coming years, Norway is making significant investments in the Country’s infrastructure. Part of this investment in development starts with the Intercity development project in South-East Norway, which is the largest transport project in Norway. The Intercity Development project consists of 270 km (167 mi.) of new doubletrack rail, capable of train speeds reaching 250 km/h (155 mph). The new stations are centrally located in the major cities, in South-East Norway, to provide the benefit to as many citizens as possible. The goal of the project is to reduce the increase in traffic, which is coupled with an increase in population, and reduce the travel times between the cities. The Intercity Development Project has an anticipated completion date of 2034. The Sandbukta-Moss-Såstad (SMS) project, part of the Intercity development, includes 10 km (6.2 mi) of new double-track railway and is situated on the Østfold Line, near the city of Moss, Norway shown in Fig. 1. The 10 km SMS-section covers three open stretches and two tunnels, including 630 m (2,066 ft) substructure for double-track railways on the open line at Sandbukta. The Moss tunnel is a 1720 m (5,643 ft) long tunnel from Sandbukta to Moss center, including a 420 m (1,378 ft) long concrete culvert. The new Moss station includes an 800 m (2,625 ft) long station area. The Carlberg tunnel is a 2350 m (7,710 ft) long tunnel from Kleberget to Carlberg, including a 200 m (656 ft) long concrete culvert.

Sep 8, 2021

By Bernardo Araya López

Dada la competitividad que existe en el ambiente empresarial durante los últimos quince años, las empresas reaccionan rápidamente ante los cambios del mercado. En este sentido, el presente trabajo señala el proceso de organización que la empresa debe considerar para lograr sus objetivos y metas. De forma, que la gerencia como concepto de gestión, genere confianza y responsabilidad sobre sus subordinados y potencie las habilidades de sus trabajadores.

Sep 13, 2001

By Géssica Padilha de Souza

Nos dias atuais, tem-se uma busca incessante por materiais que atendam às solicitações de trabalho exigidas, mas que possuam um baixo custo de fabricação. Diante disso, esse trabalho tem por objetivo o endurecimento do aço AISI 1140, que foi normalizado, temperado com resfriamento em salmoura e seguido de revenimento, com posterior caracterização metalográfica e ensaio de dureza HRC. Através desses tratamentos, foi possível aumentar significativamente a dureza do aço em questão, além das modificações nas fases da microestrutura e consequentemente, de suas propriedades.

Aug 16, 2017

By Karen Talbot, Noah Maier, Rob Jameson, Giuseppe Gaspari

A storage and drainage tunnel advancing below I-75 in Detroit, Michigan experienced sudden subsidence. The Tunnel Boring Machine (TBM) was damaged to the extent that its shield, cutting head and extensive interior components needed to be extracted and replaced along with several completed tunnel segments. The tunnel was 16 feet (4.9m) in diameter with crown over 79 feet (24m) deep at the time. The tunneling contractor immediately engaged their designers and specialty subcontractors to develop a scheme to access the machine and repair the tunnel. They required a shaft 99 feet (30m) deep, with unobstructed plan dimension of 50 feet (15m) to accommodate the large components that needed to be removed and replaced. This precluded the application of an internally braced excavation and instead earth support solutions focused on use of a compression ring. Since the completed tunnel section behind the TBM obstructed closure of the compression ring below its invert, this paper describes the innovative access shaft solution employed. A conventional compression ring was constructed using 5 feet (1.5m) diameter drilled shafts down to the tunnel crown. In front of, and to the sides of the tunnel heading, the secant shafts were extended to over 150 feet (46m) depth, creating a horseshoe of support extending 50 feet (15m) below the planned excavation invert. Larger diameter "King Pile" shafts were drilled immediately to either side of the tunnel, overlapped into each end of the secant "horseshoe". The king pile shafts, together with a heavily reinforced ring beam above the crown elevation, acted as a door frame to transfer hoop loads from the incomplete secant arc into reaction supports above and below the tunnel. These oversize king pile shafts were extended and socketed into rock over 70 feet (21m) below tunnel invert. Very tight installation tolerances were necessary to maintain secant shaft alignment to depths exceeding 150 feet (46m). The project operational, geotechnical, and quality data was managed and visualized using a custom GIS interface. This paper will present the design approach employed and review the construction and quality program selected to repair the tunnel.

Oct 1, 2022