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By R. Adams

Zirconium is the 20th most abundant element in the Earth?s crust and it most often occurs in the form of silicate (as zircon), less often in the oxide form (as baddeleyite or caldesite). Historically, the world?s production of zircon was entirely derived from mining and processing beach sands or heavy mineral sands that were being exploited primarily for their titanium content, i.e., to generate TiO2 feedstocks that would be used for making titanium pigments and, to a lesser extent, titanium metal. Zircon was then regarded as a byproduct, with the sharply fluctuating prices typical of a commodity where the supply is essentially involuntary and not truly responsive to market demand. However, in recent years, zircon has shown considerable mining investment appeal in its own right. Projects have been planned ? and some have already come to fruition ? based mainly on the zircon potential of the deposit. Booming Chinese demand for zircon to meet the requirements of the ceramic and zirconium chemical sectors has been a major factor causing zircon prices (f.o.b. Australia) to surge from US$674/t ($611/st) at [ ] the end of 2005 to beyond US$2,400/t ($2,177/st) by the end of 2011.

Jan 1, 2012

By R. D. Doepker

The dissolution of metals from various metal-mine tailings has been studied through a series of submerged tailings batch tests at U.S. Bureau of Mines laboratories. Tailings selected for this study included both reactive (as determined by column leaching studies) and benign tailings. Metal mobilization in aerated (97 pct saturated with oxygen) samples appeared to be consistently greater than metal dissolution from stagnant (79 pct or 70 pct saturated with oxygen) waters. In the early weeks of the study, sulfate concentrations increased with solid-liquid contact time, while calcium dissolution remained nearly constant. Metal concentrations varied in relation to solid-liquid contact time and aeration. Leachate pH appeared to be nearly independent of solid-liquid contact time for basic tailings. Reactive tailings having both a submerged and a surface component demonstrated increased metal mobility.

Jan 1, 1990

By Cory Loukides, Cathy Aimone-Martin

Blaster training manuals used by the Office of Surface Mining (OSM) and others are outdated and cumbersome. A new approach has been developed using Microsoft PowerPoint with a Visual Basic overlay to produce modules on CD’s that present state of the art blasting techniques. The education modules contain enhanced information on topics such as explosives and initiation products, blast design, drilling, and vibration control. The content is based on safe practices and illustrated with numerous photographs and movies. Review questions, complete with explanations for incomplete answers, enhance the learning process and keep the blaster involved. The benefits of using an electronic format include the ability to continually change and update the training modules as new products, technology and applications become available. In addition, the blaster can work at home in preparation for class work and may reduce the time away from the job. This poster session presentation will allow potential users to view and take part in the evaluation of these modules.

Jan 1, 2004

By Moussa Wone, Jeff Peterson, Filippo Azzarà, Daniele Nebbia

The DC Water and Sewer Authority's Long Term Control Plan includes tunnels, sewer separation, pumping station rehabilitation and green infrastructure to reduce combined sewer overflow (CSO) discharges to the District waterways. The Northeast Boundary Tunnel is a deep, large sewer tunnel that will reduce CSO discharges; signifi- cantly mitigate known chronic flooding in the Northeast Boundary drainage area and improve the water quality of the Anacostia River. This paper presents the unique combination of Owner and Contractor perspectives of the entire Project from conception through procurement, execution, and contract management, providing lesson learned, chal- lenges encountered, and solutions implemented to deliver the Project successfully.

Jun 23, 2024

By G. C. Branner

The bauxite diagram presented as figure 1 was developed to clarify, by graphic means, the theoretical chemical constituents of gibbsite-kaolinite-type bauxite for all possible proportions of these two minerals from pure gibbsite to pure kaolinite. The tables in the report reflect the same date. The diagram provides (1) a graphic representation of the relations of constituents with respect to a ill possible percentages of alumina and silica, (2) a basis for verifying the accuracy of analyses of gibbsite-kaolinite bauxite, and (3) a basis for estimating the type and proportion of alumina hydrate and/or silicate minerals that may be present in gibbsite-kaolinite-type bauxite. The diagram, with accompanying interpretations and use formulas, will be useful to those connected with the mining and processing of bauxite.

Jan 1, 1955

By L. J. Su, J. Y. Zhang, P. W. Gu, J. F. Xu

Surface tension of mold flux is a key factor affecting optimum casting conditions. A thermodynamic model was developed to determine the surface tension of mold flux containing fluoride based on the ion and molecule coexistence theory of slag structure and Butler’s equation. The relationship between composition and surface tension was investigated by this model. Results indicated that the calculated values showed good agreement with literature data, and the average error was 8.19%. The surface tension value of the CaO–Al2O3-based mold flux was larger than that of the CaO– SiO2-based mold flux. The surface tension in a multi-component system decreased with increasing contents of SiO2, CaF2, and Na2O, which are considered surface-active components. This trend was more significant in the CaO–Al2O3-based mold flux.

Dec 11, 2024

By Jehan Rondot, Raymond Marleau

"Des quartzites trés pars ont été découverts au cours de la cartographie de la region du lac des Martres, étape de l'étude géologique de la region de Charlevoix.On distingue quatre groupes métasédimentaires, tons con tenant des niveaux de quartzite dans an mains deux domaines géologique différents, c'est à l'ouest, clans le do¬maine gneisso-charnockitique que se situent les quartzites du groupe des Martres. Quartzite et gneiss à, grenat et sillimanite, en banes épais, constituent la formation de La Galette. A Pest, dans un environnement gneisso-granitique, les deux groupes métasédimentaires de Saint-Siméon, et de La Malbaie comprennent, par contraste, des bancs pen épais et de compositions variées. Les niveaux de quartzite dépassent rarement 50 m d'épaisseur. L'autre groupe métasédimentaires, celui de Saint-Tite des Caps, recoupé de nombreuses intrusions charnockitiques et granitiques, ne possède que de minces niveaux de quartzite.La pureté et la grande épaisseur des quartzites de La Galette suppose une histoire complexe qui se termine par des depots continentaux de climat aride, par opposition aux depots marins des autres groupes. D'autre part, la presence de ces quartzites an sein de roches Presque anhy¬dres et de haute temperature que sont les charnockites leur confére des caractéristiques de fusion sans decrepitation.Parmi la multitude de depots de quartzite qui existe clans le monde, peu sont de qualité supérieure. Or, de par sa composition chimique, le quartzite de La Galette se compare avantageusement à ceux des meilleurs gisements des Etats-Unis, de l'Europe de l'Ouest et de l'Afrique du Sud. D'accès facile pour l'exploitation, les gisements ne sont qu'à une trentaine de milles de Baie Saint-Paul ou de La Malbaie, sur le Saint-Laurent.L'utilisation en metallurgic prévue pour le quartzite de La Galette comprend la production de silicium, de ferro¬silicium et d'autres alliages de silicium. La composition du quartzite est en outre appropriée pour la production de carbure de silicium et de silicate de sodium. Les fines peuvent être utilisées pour la fabrication du verre et comme matiere de charge"

Jan 1, 1977

By G. S. Rice

This paper describes preliminary tests at the Bureau's Experimental Mine to determine, under conditions that may prevail in a bituminous coal-mine heading, how small a quantity of fire damp may bring coal-dust into suspension and ignite it. The results show that the explosion of as little as 150 cubic feet of an explosive mixture of gas and air containing 9 per cent natural gas may start a disastrous explosion of coal-dust. This is a very small volume, of gas, to cause such a result. Let us suppose that this amount of explosive mixture, as at the face of an entry which was 10 feet wide and the face was overcut to a depth of 6 feet and an upper layer of coal 2.5 feet thick had been removed, the recess so made would have a volume of 150 cubic feet. Furthermore, only 13 cubic feet of pure methane is needed in thin volume to produce this 9 per cent explosive mixture.

Jan 1, 1930

By F. W. Lane

Some months ago the Bureau of Mines began research of a fundamental character on sulphur in petroleum. In the course of this work, the usual qualitative test for sulphur in organic compounds1 was applied to certain oils that were believed to contain approximately 0.5 percent sulphur. No sulphur was found, and, as a check on the qualitative test, the oils were subjected to quantitative determination of this element by the oxygen-bomb method.2 The sulphur content of the oils ranged from 0.10 per cent to 0.50 per cent. This experience led to further trial of the qualitative test for organic sulphur, both on the oils mentioned above, and on common sulphur-containing organic substances. No difficulty was experienced in detecting the element in the latter, but with the petroleum oils the test, as usually performed, could not be relied upon to detect less than 0.60 per cent of sulphur consistently. The use of mechanically polished pure sheet copper for the detection of free sulphur, hydrogen sulphide, and perhaps other sulphur compounds has been recommended.3

Jan 1, 1927

By Joseph P. DuCarme

The U.S. Bureau of Mines explored new methods and technology for extracting coal from the Appalachian Mountain region of the Eastern United States. These methods were aimed at extracting coal from thin seams and focused on the use of "roof-fall-tolerant" (RFT) mining concepts. These methods could be used on existing, abandoned highwalls or in conjunction with new highwall mining. The research was conducted using small-scale and quasi-full-scale physical models to obtain experimental results. Details are provided on (1) the quasi-full-scale model for cross-ridge mining, (2) the quasi-full-scale model for down-ridge mining, (3) the test results of these models, and (4) recommendations for future research. Significant results include demonstration of the RFT concept, a discussion of expected coal produced from these methods, and recommendations for future research.

Jan 1, 2010

By Carlos Alberto Perim

Durante o lingotamento contínuo de placas de aço, muitas vezes ocorre uma queda acentuada de temperatura ao longo do processo. Fatores como o tempo de lingotamento, o superaquecimento inicial da panela de aço, a presença de cascão na panela, entre outros, podem alterar significativamente a taxa de queda de temperatura, levando muitas vezes à interrupção prematura do lingotamento. Neste trabalho, será mostrado o desenvolvimento de um modelo de predição de temperatura ao final do lingotamento de uma panela de aço. Este modelo permite antecipar, com razoável nível de incerteza, a temperatura final do aço no distribuidor durante trocas de panela, de forma que forneça subsídios para a tomada de decisão sobre a interrupção do lingotamento, ou a antecipação de abertura de panela com retorno de aço. Desta forma, o índice de trabalho das Máquinas de Lingotamento Contínuo (MLC’s) da ArcelorMittal Aços Planos América do Sul seria maximizado, e com possível melhoria no Rendimento de Aço. O modelo se encontra em fase de implantação e validação na MLC#3, onde foram definidos parâmetros com critérios de decisão de interrupção/antecipação de troca de panela.

Aug 17, 2017

By R. E. Radabaugh, J. M. Brown, J. S. Merchant

The Gilman district is on the northeast flank of the Sawatch Range in central Colorado. It has yielded a total of 10,000,000 tons of ore having a value of over $250,000,000. Paleozoic sediments intruded by a Tertiary quartz latite sill and unconformably overlying Precambrian intrusives and metasediments comprise the country rock of the area. The sediments strike northwesterly and dip 8° to 12° northeasterly. Structures in the Precambrian are related to the Homestake shear zone of the Colorado mineral belt. Only minor folding and faulting occur in the sediments. The principal ore bodies are massive sulfide replacement deposits in carbonate rocks. They consist of long, pipe-like mantos in the completely dolomitized Mississippian Leadville Limestone and funnel-shaped chimneys of copper- silver ore cutting across the Mississippian and Devonian strata. Mineralization is continuous from the chimneys into the mantos. The principal ore bodies are roughly in the shape of a four-tined fork which points up dip. Smaller manto deposits occur in the Cambrian Sawatch Quartzite, and fissure veins are present in the Precambrian rocks. The principal minerals in the mantos are marmatite and galena in a gangue of pyrite and manganosiderite. The chimneys consist of a central core of pyrite with erratically distributed chalcopyrite, tetrahedrite, freibergite, and occasional galena with a shell of zinc ore on the outer margin. Both the chimneys and the mantos are surrounded by imperfect shells of manganosiderite and sanded dolomite. The mineralization is of Laramide age. Hydrothermal alteration affects all rock units to varying degrees. Clay mineral alteration halos occur around the ore bodies. Hydrothermal solutions have developed sanded rock, rubble filled channels, and banded zebra textures, principally in the Leadville Limestone. Structural control of the ore bodies is not well defined. Both the location of the district and the chimneys are probably related to basement structures. The mantos are largely controlled by stratigraphic factors and a pre-Pennsylvanian karst topography in the Leadville Limestone, which were modified by hydrothermal activity, and by weak zones of northeasterly trending faults.

Jan 1, 1968

By M. Tiedtke, T. Crary, P. MacPhail, M. Ounpuu

"The SGS carbon-in-pulp (CIP) / carbon-in-leach (CIL) model was used to evaluate and optimize the carbon circuit at Alamos Gold’s Young-Davidson Mine. Plants samples (pulp and carbon) were tested in a series of small scale batch experiments to determine rates of gold leaching and adsorption on carbon from a combined flotation concentrate/tailing product. The testwork data, along with existing plant data were then used to model the performance of the existing CIL plant and optimize the circuit to improve performance and overall recovery. The primary purpose of the modelling exercise was to determine the most cost effective way to lower solution losses at the plant. The modelling was also used to learn how the various parameters in the CIL circuit affect solution losses and the gold inventory tied up on the carbon. This resulted in recommendations for minor changes in the CIL flowsheet, which were successfully implemented in the plant. The approach, results and plant changes are presented.INTRODUCTION This paper presents the details from testwork conducted on samples from Alamos Gold’s Young- Davidson gold mine which is located near the town of Matachewan, approximately 60 km west of Kirkland Lake in Northern Ontario, within the southwestern part of the Abitibi Greenstone Belt. The objective of the test program (completed by SGS Canada in 2013) was to investigate and model the combined flotation concentrate / tailing carbon-in-leach (CIL) circuit and suggest ways to improve gold recovery. The metallurgical test program included mineralogy, rheology, and carbon modelling testwork. Plant information was provided during the test program and used in the optimization process. Upon completion of the testwork, plant changes were recommended and implemented at site (October 2014). Plant results from 2014 to 2017 confirmed the modelling results."

Jan 1, 2018

By J. S. Becker

Technology developed and first implemented in the United Kingdom enables very low grade aluminum scraps containing oils, organics, plastics and ferrous metals to be directly charged, without pretreatment, into a unique melting furnace. The system has been in full scale production for four years. The oxy-fuel-based furnace design incorporates internal afterburning in the furnace's hot zone, producing excellent thermal efficiency and very low emissions. The furnace is inherently low in NOx. This paper will provide both theoretical background and extensive operating results for this new melting concept. Applications describing both purpose built new furnaces and retrofits of existing reverberatory furnaces will be presented. Extensive operating emissions data will be presented.

Jan 1, 1997

By Lilia Olaya-Luengas

A resistência à corrosão e mecânica dos aços inoxidáveis duplex dependem da distribuição de fases, portanto, é fundamental a compreensão das transformações microestruturais que ocorrem na zona termicamente afetada (ZTA) em função do aporte de calor em processos de soldagem. A fim de investigar a evolução microestrutural no aço inoxidável duplex SAF 2205 durante a soldagem, foram simulados na Gleeble dois ciclos térmicos com aporte de calor de 15 e 30 kJ/cm, considerando a temperatura de pico de 1350°C, seguido de têmpera a 500 e 250°C. As microestruturas na condição de como recebido e da ZTA simulada foram caracterizadas através de microscopia óptica (MO) e de microscopia eletrônica de varredura (MEV). Foram utilizadas diferentes técnicas metalográficas para a caracterização da microestrutura e identificadas três diferentes morfologias de austenita: nos contornos de grão, austenita Widmanstätten e a austenita intragranular, assim como diferentes frações volumétricas destas fases.

Aug 17, 2017

By Gabriel Prosofsky de Araujo

O compósito carbono-epóxi é um material altamente resistente à tração. Porém, as fibras comprimidas durante a flexão não resistem à flambagem. Dessa forma, faz-se necessário um estudo mais detalhado. Este trabalho consiste em verificar quais propriedades mecânicas dependem exclusivamente da orientação das malhas das fibras. Corpos de prova de orientação 0°/90° e 0°/90°/±45° foram processados e ensaiados em flexão de três pontos, de acordo com as normas ASTM E855 e D790, em uma máquina universal de ensaio MTS – Material Test System com capacidade de 250 kN. Inicialmente, os tecidos sofreram o tratamento superficial da silanização, promovendo a futura adesão das fibras na resina. Após a silanização, as lâminas foram montadas e impregnadas com a resina epóxi. A cura da resina do compósito foi obtida em uma estufa Fanem modelo 320°C a 120°C por uma hora, subsequentemente os corpos de prova foram obtidos utilizando-se o corte à jato d’água. Concluiu-se que as falhas de todos os corpos de prova foram devido à tração. Corpos de prova com volumes de vazios internos apresentaram menores valores de rigidez e aqueles com mecanismos de fratura como flambagem e delaminação apresentaram valores de resistência menores.

Aug 7, 2018

Prospectors were digging silver in the Ray mine area in 1873, and by 1880 high-grade copper ore was feeding a 30-ton copper furnace. In 1910, D. C. Jackling and his associates organized the Ray Consolidated Copper Company, known in mining circles as Ray Con, to exploit the Ray orebody. For 50 years, all mining was underground and the Ray mine was known the world over for innovations in mining methods. It was the first to mine important tonnage (8,000 tpd) by block caving methods. The mill at Hayden, 26 miles (41.6 km) from the mine, kept pace with the new mining methods developed at Ray and in the early 1920's flotation replaced gravity concentration by the vanner machines. First mining by open pit methods began in 1950 and in January 1955 all underground mining was discontinued. The new primary crushing plant, installed in early 1967, featured design simplicity with a low capital cost. The 54 in. gyratory crusher was installed within a total height of 6 1 ft (18.65 m) from the truck dump road bed to the floor beneath the feeder-conveyor under the surge pocket. The crusher is fed by 120-ton trucks dumping from one side only into a 200-ton hopper equipped with a horizontal splitter bar to protect the crusher spider. The crushed ore pocket, of 120 -ton live capacity underneath the crusher, discharges to a 0 to 200 fpm (61.2 mpm), variable-speed, 72 in. by 80 ft long (1.83 m by 24.4 m) sloped belt feeder, probably a first in the industry. Wood-picking stations are provided on either side of the belt so that old mine timbers and tramp iron can be removed from the crushed ore and the wood can be dropped into Dempster containers located below the belt. Counter-weighted finger gates control the bed depth on the belt at 14 in. (356 mm) and a low- level radiation unit automatically maintains a minimum of a 3 ft bed (900 mm) of material on the belt directly under the surge pocket. The conveyor is skirted for its full length and is approximately 60 in. (1.52 m) wide inside its metal skirt liners. Ten impact idlers at 12 in. (305 mm) spacing are provided under the loading pocket and remaining idlers are spaced at 18 in. (457 mm). The belt is 1 ¼ in. (31. 8 mm) thick; and, while it has occasionally been damaged by tramp material, belt life averages 11 million tons. When the belt is changed, the coiled new belt is lowered into position onto one of two belt stands mounted over the feeder, the old belt is cut, and one end is attached temporarily to the new belt. The other end of

Jan 1, 1978

By Bryan Wilson

Background ?Nickel Rim South Mine started production ramp-up in Q2, 2009. ?The main dewatering pumps were put into use in August 2009. ?3 Feluwa?multisafe?positive displacement pumps ?1700m single lift pumping ?Reliability has been an issue due to the amount of slimes and fibers (from shotcrete) at the pumps. ?Critiqued internal dewatering system to solve some issues we were having with our sumps Findings 1.Much of the final dewatering system was not in place. a)Temporary pain. Difficult to say something is not working when the system was not yet in place as per design. b)Not enough capacity to handle slimes within the system. 2.Need to address issues with the final design: a)Ongoing costs: The end design has operating costs of $2.5 million b)Scoops in Sumps: The end design relies on scoops to be used for cleaning the sumps c)Slimes Recovery: The system mixes 3 different products in the sumps along with the fibers d)Pump repair costs: The existing Tsurumi pumps are too light duty for our slimes

Nov 1, 2011

By Timothy J. Rohrbacher

This report presents a U.S. Bureau of Mines study that incorporates coal mining factors, coal recovery factors, and economic factors into the definition of an economically recoverable coal resource. The relationship between these factors to the Energy Information Administration's estimate of U.S. coal resources-the "Demonstrated Reserve Base"-is discussed. The Boltsfork 7 1/2-minute quadrangle in eastern Kentucky was selected as the study area. Results indicate that of the original 280.2 M tons of resource in the quadrangle, only 99.8 M tons (35.6%) is recoverable at a mining cost of $25 per ton or less.

Jan 1, 1994

By Francisco Geraldo Toledo Junior

Os aços inoxidáveis possuem características essenciais para um bom acabamento quando o que se busca é estética e boa resistência à oxidação. Quando se específica um aço inoxidável, o acabamento é um dos aspectos relevantes que devem ser considerados. O acabamento possui uma importante influência em algumas características do material como, por exemplo, na facilidade da limpeza e na resistência à oxidação / corrosão. Há uma grande variedade de acabamentos. Através de ensaios de oxidação a quente, medição de potencial eletroquímico, medição de dureza a baixa carga (microdureza) e medição da tensão residual via difração de raios x foi possível perceber uma diferença entre os acabamentos 2D, 2B, RO, BB, Nº4 e Nº6. A medição de tensão residual mostrou qualitativamente que o aumento de dureza e o forte amarelamento ocorrido no material com determinados acabamentos é função de uma deformação elástica na superfície imposta durante alguns dos processos de fabricação desses aços. Esse mecanismo é relevante e interfere na resistência a oxidação e corrosão nos casos estudados.

Aug 17, 2017