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By A. W. Khair

This paper presents an analysis of respirabie dust generation due to the action of a continuous miner. Underground coal cutting by a drum-type continuous miner was simulated in the laboratory using a specially designed unique automated rotary coal cutting simulator (ARCCS). An analysis of -400 mesh particles was done on gravity collected material. Samples of entrained dust were collected through the use of cascade impactors. Both samples were analyzed for size distribution and particle shape. Using the simulated coal cutter permitted variation of operating and in-situ parameters to provide information on the effects on generation of -400 mesh particles. In these tests coal blocks with an approximate dimension of 18 in. x 15 in. x 6 in. (45.7 cm x 38.1 cm x 15.2 cm) were first subjected to confining pressures, equivalent to in-situ conditions. Such blocks were then cut by the cutting head of the ARCCS, thus simulating the action of the continuous miner in underground coal mining. During the tests under a particular set of in-situ and operating parameters a number of other parameters such as 1) penetration of bit into coal, 2) penetration resistance (thrust and cutting pressures), 3) rotating velocity of cutting head, and 4) acoustic emission activity in the coal block were monitored. After each cutting cycle the fractured surfaces were photographed and a velocity survey was conducted by using a sonic technique. At the end of each experiment the cutting paths of the bits in coal were photographed using an optical microscope with an attached camera.

Jan 1, 1985

By John G. Viets, J. Robert Clark

A multielement extraction system is being used successfully to provide essentially interference-free geochemical analyses to aid in gold exploration. The Methyl isobutyl ketone-Amine synerGistic Iodide Complex (MAGIC) extraction system separates Ag, As, Au, Bi, Cd, Cu, Ga, Hg, In, Mo, Pb, Pd, Pt, Sb, Se, Sn, Te, T1, and Zn from interfering geological matrices. Quantitative extraction of these elements is accomplished over a broad range of acid normality, making it possible to economically determine all 19 elements from a single digestion or leach solution. The resulting organic extracts are amenable to analysis by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and flame atomic absorption spectroscopy (FAAS). For many years the principal shortcoming of ICP-AES was the complex spectral and stray-light interferences that were caused by the extreme variability of components such as Fe. Na, and Ca in common geological matrices. The MAGIC extraction allows determination of the extracted elements with enhanced sensitivity, from a virtually uniform matrix, by ICP-AES and FAAS. Because of its simultaneous multichannel capabilities, ICP-AES is the ideal instrumental technique for determining these 19 extracted elements. Ultratrace (sub-part-per-billion) determinations of Au and many of the other extracted elements can be made by graphite furnace atomic absorption spectroscopy (GFAAS), following back stripping of the extracts. The combination of the extraction followed by stripping of the organic phase eliminates 99.999% of potential interferences for Au. Gold determination by GFAAS from these extracts under the specified conditions yields a fourfold improvement in sensitivity over conventional GFAAS methods. This sensitivity enhancement and the interference-free matrix allow highly reliable determinations well into the parts-per-trillion range.

Jan 1, 1990

By Manuel Cabrera M

El presente texto señala el uso del carbón como medio de concentración y recuperación de los metales preciosos. En este sentido, las posibilidades del carbón como medio de recuperación de valores metálicos de oro y plata son a través del carbón en pulpa, columnas en carbón y carbón en lixiviación-adsorción, las cuales tienen sus propias tecnologías y particularidades para cada mineral.

Nov 8, 1984

By F. Habashi

Siberia, a vast country rich in mineral resources and a large number of different ethnic groups. To the east of Lake Baikal is Buryatia with capital Ulan Ude. The Buryat are closely related to the Mongolians. Ulan Ude is connected to Ulaan Baatar (Ulan Bator) the capital of Mongolia by train – a 26 hours trip. Getting a visa to Russia is not a simple case. Visits to metallurgical research laboratories, Lake Baikal, and historical museums are enriching experience.

Jan 1, 2006

By Carlos G. Philips J.

El presente texto señala el proceso de combustión del carbón en el horno ciclónico. Por tal motivo, se describe el principio de operación, donde el combustible se quema a altas temperaturas y la mayor parte de la ceniza se retiene de forma líquida en el área húmeda del horno ciclónico, evitando su paso al caldero y la contaminación del aire. En cuanto a los combustibles empleados, no se ha encontrado la adaptabilidad de un quemador que pueda operar simultáneamente con combustibles sólidos, líquidos o gaseosos, aunque es posible adaptarlo al uso de varios tipos de combustibles: carbón bitúminoso, lignito, antracita, así como también petróleo y gas natural. Los calderos usados dividen el horno del caldero en dos secciones, una alta y otra baja. Entre las características de la operación tenemos la resistencia, fuerza auxiliar, molienda del carbón. Finalmente, en el proceso de eliminación del sistema de horno ciclónico, se utilizan los tanques para ceniza fundida dado que operan a presión a fin de no detener el caldero cuando se extrae la ceniza fundida.

Aug 20, 1965

By E. C. Tarpley

The Federal Bureau of Mines has studied solvent extraction as a means of concentrating the mineral components in coal. Solubilities of a number of American coals were determined using abietic acid as a solvent. The effect of rank on solubility was investigated, and maximum solubility was found with coals of intermediate rank. Vitrinite is the most soluble petrographic component; fusinite, micrinitc, and exinite are nearly insoluble. Spore exines also have a low solubility. Abietic acid is a hydrogen donor and reduces pyrite to ferrous sulfide. Mild hydrogenation of high-molecular-weight fragments of the coal structure to those of lower molecular-weight probably contributes to the solvent action. Even where solubility of the coal substance exceeds 90 percent, contamination of the mineral matter with coal makes identification of the mineral components difficult. Further separation might be possible by the application of float and sink techniques to the residue. INTRODUCTION Work n the solvent extraction of coal is conducted to recover commercially useful products and to characterize coal;. and obtain information on their structure. Some coals, particularly those of low rank, contain waxes, resins, and humic acids which can be removed by solvent extraction and find varied industrial uses. In World War II, solvent extraction of coal was conducted on a commercial scale in Germany to obtain a low-ash feed material for hydrogenation and to produce electrodes carbon for the aluminum industry.4 5/

Jan 1, 1960

By Grano S. R, Kilgariff B

The Renisun Tin concentrator treats an ore containing I's per cent till as cassiterite and 22 per cent sulphur in a range of sulphide minerals. predominantly pyrrhotite. The sulphide minerals are removed by flotation using copper sulphate (CuS

Jan 1, 1997

By F. W. Petersen

Slurry reactors are being used extensively throughout the chemical, biochemical and mineral processing industries. This paper describes the interaction between fine ore particles and granular porous adsorbents such as activated carbon and ion-exchange resins in a stirred tank reactor. Gold and silver cyanides were used as adsorbates to detect changes in the mass transfer characteristics of the adsorbents, which were ashed to determine the loading of ore particles. A simple kinetic model incorporating film diffusion, intrapanicle diffusion ~d the adsorption equilibrium, was used to interpret kinetic data and to estimate the effect of slurry conditions on the diffusion parameters. It was observed that the equilibrium loading of fines in the adsorbents was independent of their concentration in the slurry. Furthermore, the presence of these panicles inside an adsorbent decreases the effective diffusion of gold or silver cyanides into the adsorbent matrix. When fine suspended solids are present in the reactor, a decrease in the effective availability of the superficial surface of the pre-saturated adsorbent panicles for mass transfer from the liquid phase was observed. This newly defined surface availability factor was dependent on the concentration, panicle size, and the zeta potential of the fine particles in suspension.

Jan 1, 1993

By J. Sammarco

The U.S. National Institute for Occupational Safety and Health (NIOSH) is conducting mine illumination research to determine if light-emitting diode (LED) cap lamps can improve safety by reducing glare. Glare can impede a miner?s ability to see hazards and to safely perform their work. Another objective is to determine if a person?s age is a factor. This is important because the workforce is aging ? the average miner is now about 43 years old. Three cap lamps were used to evaluate glare: an incandescent cap lamp, a commercially available LED cap lamp and a NIOSH prototype LED cap lamp. Thirty NIOSH personnel from the Pittsburgh Research Laboratory (PRL) served as test subjects. Three age groups were established with ten subjects in each group. Testing was conducted in the Mine Illumination Laboratory (MIL) of NIOSH PRL. The results indicate no statistically significant difference in discomfort glare among the incandescent and LED cap lamps. However, an analysis of variance for disability glare indicates that the LED cap lamps were superior for the older subjects. Disability glare scores for the oldest subject group improved 53.8% when using the NIOSH prototype LED cap lamp compared to the incandescent cap lamp and 36.5% compared to the commercial LED cap lamp. It ap­pears that, given the conditions of this study, LED cap lamps will not increase discomfort glare and can enable significant improvements in disability glare for older workers. It is also evident that not all LEDs are created equal. The disability glare improved the best for older workers when they used the NIOSH prototype LED cap lamp, which has a different spectral power distribution (SPD) (more short wavelength energy) than the commercial LED cap lamp. Therefore, for disability glare, the results suggest that the SPD is an important factor to consider in cap lamp design.

Jan 1, 2009

By Barlow S

The Kelian Gold mine project won two excellence awards from the Victorian Division of the Institution of Engineers, Australia. It was a challenging project, fast tracked in a remote and inhospitable tropical environment. The creation of a profitable and efficient mine was a significant engineering and project management achievement. The difficulties encountered and the way they were managed provide valuable lessons. These include the importance of sufficiently detailed engineering in all aspects of the job to enable the best estimates possible to be prepared during feasibility studies, the need to prepare the project scope and execution plan with disciplined and rigorous attention to detail by a highly experienced team and the value of identifying, assessing and mitigating risk and uncertainty during execution. The practical benefits of applying these lessons were demonstrated in the successful management of technical uncertainty on the recent diversion of the Kelian River to allow the expansion of the Kelian mine.

Jan 1, 1997

By Charles H. Behre

KEYNOTE of the mining geology sessions was the preparation for an extensive war with all that this implies as to the need for strategic minerals, both metallic and nonmetallic. Nevertheless the sessions also included many papers of less urgent, more theoretical interest. The stress of wartime production had the effect of giving an unusually full and rich program, the longest in recent years, with sessions continuing virtually throughout the meeting. Some papers dealt with geophysical prospecting as applied to mining geology; others were concerned with the grand strategy of mineral reserves and thus involved the industrial minerals; such "borderline" subjects were presented before sessions held jointly with the Geophysics Committee or the Industrial Minerals Division.

Jan 1, 1942

By Rosa G. de Pena

From the MAP3S Precipitation Chemistry Network data bank five years of data from January 1, 1977 to December 31, 1981 have been analyzed. No definite trend has been observed in the concentrations and the total depositions in the analyzed period. Comparison between the weekly and event samples show that the weekly samples could underestimate the total deposition. Preliminary results show that there is a reasonably good correlation between the precipitation composition and the emissions feeding the air in which the precipitation is formed.

Jan 1, 1983

By U. Cetin

The Nevada Test Site is located approximately 65 miles northwest of Las Vegas, NY. The site was primarily used by the Department of Energy for the field testing of nuclear weapons and contaminated by several million cubic feet of low-level radioactive wastes, heavy metals, volatile and non-volatile organics, and explosive materials. Leaching and transportation of these contaminants are creating severe environmental problems. The purpose of this study is to examine pozzolan, a natural alumina-silicate mineral, as a possible replacement of the existing impermeable barriers (clays). In the first phase of this study, radionuclide sorption characteristics of pozzolan were investigated. This paper will present the results of the sorption tests for the target radionuclides.

Jan 1, 1998

By Pierre St-Julien, Réjean Hebert, M. Racine, Roch Gaudreau, Pierre Lacoste, Michel Rocheleau

"Les unités volcano-sédimentaires de la ceinture de l'Abitibi à l’est de Val-d' Or ont été regroupées en quatre domaines litho tectoniques. Du nord vers le sud, nous reconnaissons les domaines d'Assup, de Garden lsland de Val-d' Or, de Trivio et de Villebon. Deux de ces domaines (Garden Island et Trivio) correspondent à des couloirs de déformation, d’envergure régionale et d’orientation approximative E-W. Les trois autres domaines sont caractérises par des volcanites defond océanique de type MORB (tholéiites et komatiites) qui sont en position inferieure; ces volcanites sont surmontées par des sédiments marins de type turbidite (domaine de Ville bon) ou évoluent dans le temps, soit vers un volcanisme bimodal d'affinités tholéiitique et calco-alcaline ( domaine d'Assup), soit vers un volcanisme d'arc insulaire (domaine de Val-d'Or). Il n'existe aucune certitude de corrélation litho stratigraphique entre les différents domaines et l'on doit considérer la possibilité que ceux-ci représentent l'accolage tectonique de terranes de nature et d'origine différente.Les principales caractéristiques structurales de la région sont regroupées en quatre étapes de déformation dont trois sont archéennes et la quatrième attribuée à l'orogenèse grenvillienne. Au moins cinq facies métamorphiques ont été reconnus: I) un facies régional faible propre à la province du Supérieur, 2) un facies de cornéennes a amphibole en périphérie du pluton de Pershing, 3) un facies hydrothermal dans la zone tectonique de Cadillac, 4) un facies régional moyen dans la zone de bordure de la province de Grenville, et 5) un facies régional élevé a l'intérieur de la zone structurale du front de Grenville.Le front de Grenville est défini dans la région par l’apparition subite des ortho gneiss au faciès métamorphique élevé et par la disparition du grain tectonique E-W. Le contact brusque entre les deux provinces pourrait correspondre à une zone de chevauchement de la province de Grenville sur la province du Supérieur. La région étudiée est l’hôte d’un gite majeur de sulfures massifs et de plusieurs gites et indices aurifères; elle présente des cibles favorables pour l’exploration minière dans le contexte tectonométa-morphique de l'influence grenvillienne. L'intérêt de la Formation de Val-d' Or pour les métaux de base et le potentiel aurifère des couloirs de déformation d'orientation approximative E-W, sont bien connus. Les structures grenvilliennes NE-SW, qui se développent vers l'est, représentent aussi des cibles intéressantes, en particulier dans les secteurs ou elles intersectent des cisaillements E-W kénoriens."

Jan 1, 1990

By R. Fritschen

In order to investigate locations, source parameters, and source mechanisms of mining induced seismic events, a local network of seismic stations was installed at a coal mine in the eastern part of the Ruhr District (Germany). The recorded events were located with the help of an anisotropic velocity model, which accounts for the fine layering of the carboniferous strata. Most of the events took place about 50 m above the working Luise 76-10. Their locations correlated with the advancing working face, and the number of events increased when pillar edges were undercut. The source mechanism, i.e., the orientation of the fracture plane and the direction of displacement on this plane, could be determined for several seismic events. The majority of them was characterized by a fracture plane parallel to the working face and an almost vertical dislocation on this plane towards the goaf a mechanism resembling the breaking down of the hanging wall. The fracture plane had a dimension of about 100 m. Probably the fracturing of a sandstone layer, located approximately 40 m above seam Luise, was responsible for the observed seismicity

Jan 1, 1999

By John P. Hager

This study investigated the formation of vapor complexes between aluminum chloride and the chlorides of iron, titanium, and silicon. For the A1-Fe-C1 system the proposed gaseous complex species is Al2Fe2C112(g), which is formed according to the reaction 2A1C13(s) + 2FeCl3(s) = Al2Fe2C112(g) The corresponding free energy expression was determined to be ?G° = 38091.49 - 71.45 ? T 400 < T < 600°K The vapor composition above AlC13 melts contaminated with FeC13 was calculated. In the Al-Ti-CI and Al-Si-Cl systems the proposed vapor complex species are Al2Ti2Cl14(g) and Al2Si2Cl14(g) respectively. Free energy expressions were estimated for the formation of the two complex species. Again, the vapor composition above AlCl3 melts contaiminated with TiCl4 or SiCl4 was determined. The results of this study were compared with previous studies on the three systems.

Jan 1, 1980

By Gordon T. Austin

The combined value of production of natural abrasives, which include tripoli, special silica stone, garnet, staurolite, and emery, increased about 4% in 1990. The decrease in the value of tripoli production was the result of a decrease in total production. Emery decreased owing to a decrease in the volume of the material produced. Special silica stone experienced a decrease in unit value and in the quantity produced. Garnet showed an 8 % increase in quantity and an 8 % increase in unit value. Staurolite increased about 38 % in the quantity produced, and the value of production increased about 36 %. The fused aluminum oxide industry showed a 12 % decline in the quantity produced and a 13 % decline in the value of production. The silicon carbide industry saw a 47 % decrease in the quantity produced and a 23 % decrease in the value of production. Combined, the industries decreased 17 % in quantity and value compared with those of 1990.

Jan 1, 1993

By Charles H. White

METHODS in colorimetry are based on the assumption that the intensity of the color of a definite volume of solution is directly proportional to the quantity of the color-producing substance&apos; present. In the preparation and examination of colored solutions there are three ways in which the depth of color may be varied. These variables are; (1) the quantity of the coloring matter, (2) the quantity of the solvent, or the dilution, and (3) the thickness or depth of that portion of the solution examined. With these three variables as a basis, three general methods in colorimetry have been devised, all of which have been used in the determination of carbon in steel. In the first method, the quantity of the solution is kept the same for both the unknown steel and the standard, and the sections compared are of equal thickness, while the quantity of the standard is varied until the color obtained is of the same intensity as that produced by a definite quantity of the unknown steel. In laboratories where this method is used there is pre¬pared and kept for permanent use a series of solutions with varying amounts of the standard, representing the percentages of carbon from the lowest to the highest demanded in that laboratory. These standard solutions are kept in bottles, or test-tubes of equal diameter, and are arranged in series from the faintest to the most intense color, so that it is a simple matter to find the place of the unknown steel in the series, when the solution is of a definite volume and is contained in a tube of the same diameter as the standard tubes. In the second method, equal quantities of the standard and of the unknown steel are dissolved, the standard is diluted to a definite volume, and the solution of the unknown steel is di-

Sep 1, 1906

By William R. Chedsey

ALTHOUGH few changes can be reported in educational methods at the mineral technology schools during 1940, other events have taken place of direct interest to, and that will have a profound effect upon, mineral industry education on the United States. In the erection of new buildings, some notable changes have been made on the campus, The U.S. Bureau of Mines Experiment Station at the University of Utah, Salt Lake City, was dedicated on May 20. The construction and equipment of this building cost between $300,000 and $400,000. It will be the general headquarters for the metallurgical division of the Bureau and will have a pronounced effect upon the mineral industries research program at the University.

Jan 1, 1941

By Albert J. Phillips

The effect of impurities on the flowsheet in the smelting and refining circuits for copper, lead and zinc is reviewed and the interflow of by-poduct metals from copper, lead and zinc plants is pointed out. The principal points of separation of all impurities in the circuits are indicated and the additional steps added to these circuits in order to effect impurity separation me shown. In this day and age, when difficult metallurgy is mentioned, one thinks of the extraction of more refractory or possibly the alkaline earth or rare-earth metals. It is true that the extraction of metals having a high affinity for oxygen and deleterious solubility for that element in the liquid metal, affords some of the most difficult extractive metallurgy problems. When this is coupled with an affinity for hydrogen, nitrogen, and carbon a devious approach is required that sometimes rivals the complexity of the metallurgy with which this paper deals. However, in all such cases the aim is for a simple

Jan 1, 1962