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By S. J. Lötter, J. T. Nel, W. Purcell

"SynopsisGlow discharge optical emission spectroscopy (GD-OES) is an analytical technique used in the analysis of solid, conducting materials. Though primarily of interest as a depth profiling technique on samples with varying layers of both conducting and non-conducting materials, it is also capable of rapid bulk analysis of homogenous, solid samples. GD-OES combines the advantages of ICP-OES (wide detection range, speed, and lack of interferences) with the solid sampling of XRF techniques. This allows the analyst to not only quantify the elemental composition of a sample, but to evaluate it in terms of homogeneity with depth, a field in which auger electron spectroscopy (AES) and secondary ion mass spectrometry (SIMS) have traditionally been the primary techniques. Although GD-OES does not replace these useful techniques, it does offer various advantages over them, making it an excellent complementary analytical tool.In GD-OES analysis, a low-pressure glow discharge plasma is generated with the sample material acting as a cathode, accelerating the cations in the plasma towards the sample surface. This bombardment causes the sample material to ‘sputter’, essentially knocking free atoms or molecules of analyte material, which are then drawn into the plasma where they are excited. The light emitted by this excitation is then diffracted to separate the wavelengths emitted by the specific elements and detected by a spectrophotometer. The intensity of the signal is directly proportional to the quantity of analyte element present in the sample, allowing simple calibration and quantitative determination of the elements. Technological improvements made in the past twenty years or so have significantly increased the usefulness of GD-OES for surface analysis. Faster plasma stabilization and start-up allow for the quantification of surface layers as thin as 1 nm. Sputter rates have been accurately measured for many common materials, allowing them to be built into software libraries in the instrument’s control software. This dramatically expands the usefulness of this software and the ease of performing analyses.GD-OES analysis of nuclear materials allows for the rapid determination of the elemental composition without the requirement of initial dissolution. The thickness of any corrosion layers on nuclear materials can also be determined."

Jan 1, 2015

By L. Cheng

This report presents the results of a Bureau of Mines laboratory investigation of the effect of water sprays in reducing respirable dust that escaped the face area of a full-scale wooden model of a mine en-try containing a wooden model of a ripper-type continuous mining machine and exhaust brattice. Areas examined were (a) the general effectiveness of a low-pressure water spray system mounted on top of the mining machine boom, a high-pressure spray system mounted under the boom, and the combined top-and bottom-spray systems, and (b) the effect of these three spray systems on the capture of coal dust particles of different sizes. Dust was injected into a sump cavity at the face. Airborne respirable dust concentration was mea-sured behind the brattice with a personal sampler and cyclone, and particle size distribution was mea-sured with a cascade impactor. When used alone, the top-spray system captured about 55 pct of the respirable dust in the face area and the bottom-spray system captured 60 pct; the capture efficiency of each system is decreased when they are used simultaneously. From a mass-concentration viewpoint, each spray system preferentially captures larger dust particles.

Jan 1, 1988

By R. E. Whitehead

"Alkali/alumina and MgO/alumina molar ratio plots graphically portray both chemical and mineralogical changes accompanying potassic, phyllic, argillic, chloritic, and alunitic alteration of quartz monzonites and granodiorites hosting porphyry (as well as lode and greisen) ore deposits. The molar ratio plots can be used to identify different types of alteration. In most cases, the identification based on molar ratios coincides with petrographic data. In those instances where the molar ratio and petrographic identifications do not agree, the mineralogy might need to be re-examined. Hydrothermal alteration studies using trace elements could benefit from the application of complementary alkali/alumina molar ratio plots.Le diagramme des rapports molaires alkali/alumine et MgO/alumine illustre clairement les changements chimiques et minéralogiques qui accompagnent les altérations potassique, phyllique, argillique, chloritique, and alunitique des monzonites à quartz et des granodiorites encaissant les gîtes de type porphyrique, ainsi que des veines et des greisens qui leur sont associés. Les diagrammes de rapports molaires peuvent être utilisés pour identifier divers types d’altération. Dans la plupart des cas, l’identification basée sur les rapports molaires est en accord avec celle basée sur les données pétrographiques. Là ou il y a désaccord entre les rapports molaires et les données pétro-graphiques, il peut être nécessaire de réexaminer la minéralogie. Les études de l’altération hydro-thermale accompagnées d’une étude des éléments traces auraient avantage à utiliser un diagramme des rapports molaires alkali/alumine."

Jan 1, 2009

By M. J. Sapko

A moderately scaled apparatus was developed by the Bureau of Mines to determine the fire resistance characteristics of mine conveyor belts and similar type materials. The design of the apparatus was based upon data obtained in full-scale fire tests and features a radiant panel to preheat the belt and a methane-oxygen ribbon burner to ignite the sample under ventilating condi¬tions in a rectangular duct. The test method overcomes the limitations of existing laboratory-scale methods and provides a measure of both ignitability and flammability in quantitative terms. Flame propagation depended upon such variables as air velocity, ignitor heat flux, and belt width and height in the test chamber. Data are presented for nine belt materials and fire resistance ratings are proposed in terms of the flame spread rate, heat release rate, and the critical ignitor heat flux. The ratings discriminate between the fire hazard posed by different fire-resistant belts and tend to be in reasonable agreement with those obtained in full-scale fire tests.

Jan 1, 1981

By A. N. Holden, W. E. Seymour

DURING the last several years, the U-Zr system has been studied at many laboratories as one of the research programs sponsored by the Atomic Energy Commission. The equilibria in part of this system have been difficult to determine, although the phase diagram from 0 to 60 atomic pct Zr has been established with reasonable certainty. Existing diagrams of the system vary appreciably beyond 60 atomic pct Zr, particularly with regard to the existence of an intermediate phase. Most existing diagrams show a transformation or reaction horizontal near 600°C. In 1955, a collection of uranium phase diagrams' was prepared at the Battelle Memorial Institute and the U-Zr diagram in that collection contained a questionable region in the vicinity of 60 to 80 atomic pct Zr. Summer-Smith" has published a phase diagram of the system that shows no intermediate phase. Summer-Smith did his work with powders and found only the uranium and zirconium eutectoid mixture from X-ray patterns of material annealed below 600°C. Mueller3 at Argonne National Laboratory did similar work with filings, and he found that initially there was a pattern of an intermediate phase, but on long-time annealing

Jan 1, 1957

By L. J. Kane

Conventional methods for determining the size of dust suspended in a gas require that agglomerates (clusters of particles) first be broken into particles, but in evaluating industrial dust-removing equipment the size of the agglomerates as they actually exist in the gas stream is far more important. This paper presents results of an investigation by the Federal Bureau of Mines to develop methods for determining the size of dust agglomerates suspended in a gas stream. The studies are part of the Bureau's continuing research on synthetic liquid fuels. The size and size-distribution of agglomerates as they exist when the gas reaches the filter was determined by using a membrane filter in conjunction with a dust count under a microscope. A membrane filter is a cellulosic sheet about 150 microns thick containing millions of holes per square centimeter--holes of uniform diameter that run directly through the sheet without interconnection.

Jan 1, 1960

The Manto Verde mine is found in the coastal ranges of the Atacama desert, 1000 km north of Santiago, Chile . The deposit is a fault-breccia specularite-oxide copper mineralisation hosted by the Jurassic andesites of La Negra Formation. It is located in a tensional fault that joins twoparallel arms of the Atacama Fault. The mine is in feasibility study: reserves are of the order of 60 Mt at 0.9 wt per cent soluble copper; mining will be undertaken at a rate of 11 000 tpd utilising an open pit and the ore will be heap-leached with acidified sea water, with copper recovery and by SX/EW.

Jan 1, 1992

By Edward Thomas

Yucca Mountain Overview The U.S. Department of Energy?s Yucca Mountain Project is a geologic repository project designed to receive, handle, package, transport, and emplace spent nuclear fuel and high level radioactive waste. The planned repository would be located in Yucca Mountain on the western edge of the Nevada Test Site, about 90 miles northwest of Las Vegas, Nevada, and would include both surface and subsurface areas. Yucca Mountain rock formations consist of successive layers of volcanic rocks (called tuffs) approximately 14 to 11.5 million years old, formed by eruptions of volcanic calderas to the north. With the volcanic rock the potential for methane emission is not an issue and the subsurface repository is a non-gassy (methane) classification. This paper will provide a summary of the development ventilation system design that provides fresh air for subsurface construction activities, and the emplacement ventilation system design that removes heat generated by the waste packages. The subsurface layout, illustrated in Figure 1, contains 108 emplacement drifts, one Performance Confirmation(PC) observation drift, nine intake/exhaust shafts, and three access ramps. The existing Yucca Mountain facilities, shown in bold lines in Figure 1, include a 7.8 km long, 7.62 m (25 ft) diameter U shaped tunnel that is formed by the North and South Ramps at both ends of the Exploratory Studies Facility (ESF) drift and a 1.5 km long, 5.0 m (16.4 ft) diameter Enhanced Characterization of the Repository Block drift (ECRB) that were constructed from 1994 through 1998. These drifts were used for site characterization activities and have been incorporated into the subsurface repository configuration. The unexcavated perimeter access main and exhaust main drifts are typically 7.62 m (25 ft) diameter TBM excavations and the emplacement drifts are 5.5 m (18 ft) diameter TBM excavations. The turnouts leading into the emplacement drifts are to be excavated by either mechanical, or drill and blast methods and serve as the launch chambers for the emplacement drift TBM excavations.

By G. Danko, R. Tiwari, J. Knowles

Many excavation and loading tasks require equipment operators to simultaneously coordinate the motion of multiple machine links, in order to achieve complex tool trajectories. Efficiency, ore selectivity, and machine wear, are all affected by the skill level and attentiveness of the operator. A software-based kinematics reconfiguration system designed to assist operators with various tasks has been implemented on a small experimental excavator using our new differential control architecture. Kinematics transformation and feedback control algorithms are being developed and tested using computer simulation, and the results implemented on the experimental excavator. Several task-specific kinematics transformations, including a virtual revolute-to-Cartesian machine reconfiguration and computer-assisted bucket steering and stabilization have been successfully tested. Progress, challenges, results, expected benefits, and planned work are described.

Jan 1, 2006

By Steve Polegato, J. Coady Marsh, Gary Landry

The Donkin-Morien Mine in Cape Breton, Nova Scotia, has successfully completed the excavation of a 7.6m (25-ft) diameter access decline over a distance of 3.5km out under the Atlantic Ocean. The tunnel, completed in December 1984, was driven through a sedimentary sequence of sandstone, siltstone, mudstone and various gassy coal seams prior to intersecting the Harbour Coal Seam where development work will commence. The tunnel was driven by a Canadian prototype tunnel boring machine (TBM) manufactured by Lovat Tunnel Equipment, Inc., Toronto, Ontario. The 7.6m (25-ft) diameter full-face shielded TBM operated at various grades from 0-20%. This paper outlines the TBM design, excavation, support and backup system utilized in the drivage. Problems encountered and drivage rates will be addressed.

Jan 1, 1985

The maximum current density at which conventional copper electrowinning plants will result in satisfactory, adherent, and dendrite·free cathodes is determined by the thickness of the diffusion boundary layer. A decrease in the value of that thickness will permit an increase in the current density. This fact is utilized to develop a high current density cell in which the reduction of the boundary layer thickness is accomplished by means of a specially designed electrolyte circulation system. The high current density cell is used to determine the effect of current density on such process parameters as current efficiency, cell voltage, power consumption, and cathode purity. A number of empirical equations are developed for the purpose of estimating the magnitude of these effects.

Jan 1, 1972

By Ganesh Kumar S.

"Soil reinforcement using stone columns is one of the well-developed ground improvement techniques for soft clay deposits. The load carrying capacity can be further improved by encasing it with geosynthetic material around the column which offers effective lateral confinement, prevents column contamination with improved drainage and strength characteristics. Improvement of undrained shear strength using vacuum consolidation is a type of hydraulic modification technique in which negative pore pressure will be developed which increases the effective stresses in soil without changing the total stress. The improvement in effective stress resulted in improved undrained shear strength of surrounding soil. In this research work, combined geosynthetic encased stone column and vacuum treatment method is examined for improving of extremely soft clay soils. The improvement in the time rate of consolidation and load carrying capacity of stone columns after vacuum treatment was studied using experimental investigations. It was observed that both load carrying capacity and stiffness of the encased stone column increased significantly with vacuum application. Also, application of vacuum accelerates rate of primary consolidation settlements. With this reduction in time, the construction activity can be accelerated which makes the project economically beneficial.INTRODUCTIONThe rising demand for the land for country’s infra-structure compels the engineers to work with even soft clay deposits which are not suitable for construction activities. As these soils have low bearing capacity and excessive settlement characteristics, ground improvement methods will be required before commencing construction. Among all available treatment methods, soil reinforcement and hydraulic modification technique are well-known popular techniques for its reduction in time required for consolidation settlement with improvement in load carrying capacity. When stone columns are used as a reinforcing member, it creates drainage with improves bearing capacity (Greenwood, 1970; Mitchell & Huber, 1983). However, the limitation includes lack of lateral confinement in very soft clay deposits, possibility of contamination, reduction in drainage path all which leads to the failure of stone columns (Mckenna et al, 1975). To overcome these limitations, encasement using geosynthetic material was adopted around the column which offers better lateral confinement, prevents intrusion of finer clay particle inside the column and provides effective drainage path with improved load bearing capacity characteristics (Van Impe, 1986; Raithel et al. 2005; Short et al. 2005; Borkemper et al. 2006; Murugesan & Rajagopal 2010; Kumar et al. 2014)"

Jan 1, 2017

By Daniel Angelo Zattera Milesi

Em determinadas rotas de manufatura de componentes automotivos, principalmente de produtos do segmento rodoviário pesado, são muito comuns processos de desempeno a quente, assim como outros procedimentos como arqueamento e alinhamento de longarinas. O presente trabalho tem por objetivo traçar os principais impactos destes processos sobre o material de alta resistência e baixa liga norma DIN EN 10149 S700MC em uma rota de fabricação de produtos automotivos com interferência de um procedimento a quente. Esse material, quando submetido ao ciclo térmico para alinhamento a quente, através do aquecimento de algumas regiões pontuais e do posterior resfriamento ao ar calmo têm suas propriedades mecânicas alteradas. Para comprovar isso, foram reproduzidas as condições do processo atual para mapeamento de dados de temperatura para os subsequentes ensaios de laboratório. Comparando as amostras submetidas ao ciclo térmico, com as produzidas com a mesma matéria prima sem aquecimento, pode-se verificar o impacto causado pelo processo de alinhamento a quente utilizado sobre as propriedades mecânicas do material. Os resultados mostram que o aço DIN EN 10149 S700MC apresenta alterações expressivas em todos os ciclos realizados. Com isso, ocorrem modificações na microestrutura pelo ciclo térmico ocasionando a diminuição de algumas propriedades mecânicas importantes, como tensão de escoamento, dureza e a tensão limite de fadiga.

Aug 16, 2017

By C. D. Litton

Laboratory experiments were conducted to determine the responses of a prototype smoke detector and a commercially available photoelectric smoke detector to smoke particles generated from various combustion sources. The prototype smoke detector combines optical scattering measurements with ionization chamber measurements in order to reduce/eliminate nuisance alarms due to the presence of airborne dusts or diesel exhaust particles. The commercially available smoke detector is designed for use in harsh environments where airborne dust represents a major problem due both to nuisance alarms and detector contamination. In the experiments, the responses of the two detectors were measured when exposed to smoke particles from the exhaust of a diesel engine and from a variety of fire sources, including wood, coal, styrene butadiene rubber, and No. 2 diesel fuel. For the solid fuels, data were obtained for both smoldering and flaming combustion. This report describes the experiments, their results, and the use of these results as they apply to early-warning fire sensors capable of the rapid and reliable detection of fires in atmospheres that may or may not be contaminated by either airborne dust or the products produced from diesel engines. Subsequent to these laboratory experiments, six smoke detectors were installed in an underground limestone mine for further testing and evaluation. DISCLAIMER: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By L Barrere, J P. Sykes, A Trench, R S. Davies

Western Australia (WA), alongside Brazil, has remained at the forefront of the global seaborne traded iron ore market for over 40 years. Despite this apparent stability and strong market position, WA continues to face strong external international supply-side competition, mainly from Brazil, but also periodically from often marginal, non-traditional sources of iron ore. Additionally, WA iron ore supply has undergone significant decadal change internally, both of an evolutionary (brownfields expansion) and revolutionary nature (major new greenfields projects). Since 2006, a new generation of WA-focused iron ore explorers, developers and producers have emerged.The majors, BHP Billiton and Rio Tinto, have expanded mine production to record levels and the Roy Hill project is now approaching nameplate capacity. Fortescue Metals Group (FMG) is, however, the largest new market entrant of the last decade, delivering upon their vision of becoming the ‘new force in iron ore’. Unlike most of the other new WA market entrants, FMG’s operations are substantive. Most of the other smaller, new WA iron ore miners have struggled during the period of falling prices, though it is worth noting that collectively they have made a material supply-side impact during the price boom – typical of marginal supply. Finally there have been some contributions from new magnetite projects, however, the delivery and economics of these projects have not met expectations.In this paper, we touch briefly upon the key global market changes of the last decade, namely China-driven demand growth and the changes to the pricing mechanisms for iron ores – before reviewing the rise in WA iron ore supply in response to these markets. We finish by focusing on the most significant WA-focused supply-side development of the last decade, the rise of FMG as a major new supplier and the strategic situation that facilitated its rise. The unprecedented China-led rise in iron ore prices felled many traditional barriers to market entry into an oligopolistic industry, allowing many new market entrants (in WA and around the world). However, the downturn in iron ore prices resurrected these barriers to entry, with only FMG (thus far) breaking the entry barrier with significant scale. Difficult corporate decisions have been forced upon the smaller WA iron ore miners who, in some cases, will now struggle to further expand, or indeed continue to operate in the longer run.The changes that have taken place over the last decade of WA iron ore production hold insights for other emergent mineral commodity exports from the state. Successful market entry, even when industry barriers are high, does not always require an immediate low-cost production assumption alongside a strong balance sheet. FMG could see a new market, within an established commodity market, target an appropriate and new product at it, overcome temporarily-felled barriers to entry in infrastructure and finance, then innovate and aggressively cut costs ensuring it was behind the barriers to entry when they rose again after the price boom.CITATION:Barrere, L, Trench, A, Sykes, J P and Davies, R S, 2017. New generation Western Australian iron ore – strategic insights far beyond the Pilbara?, in Proceedings Iron Ore 2017, pp 375–386 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Tom Dettweiler, Robina Sharpe, Wright. Michael

The International Seabed Authority and a number of countries have or are in the process of developing environmental impact assessment guidelines and legislation for seafloor mineral development. The formal decision to grant a project an environmental permit is based on an environmental and social impact assessment (ESIA), culminating in an environmental impact statement (EIS). The EIS needs to be supported by sufficient data upon which an assessment of impacts can be made and mitigation measures developed. Given the remote locations of many seafloor prospects, collection of sufficient environmental data to inform an EIS is often a difficult, expensive and lengthy process.

Sep 1, 2014

By Tobías Posadas

"El presente texto señala los beneficios que otorgan las leyes 15584 y 16066 en favor de la pequeña minería; así como sugiere las normas reglamentarias para que estos sean aprovechados por el mayor número demineros. En ese sentido gozan del beneficio de canon minero, aquellos que tengan menos de mil hectáreas y produzcan menos de mil toneladas al mes, así como los libera de un pago de sobrecanon, los exonera salarialmente, los libera de los impuestos de registro y reduce del importe de los avisos de denuncios. "

May 1, 1967

By R Simcock

Why Rehabilitate? Legislative Requirement Land rehabilitation is a condition of resource consents for mining. Clause 17 (1) of the Resource Management Act 1991 (duty to avoid, remedy, or mitigate adverse effects) provides the legislative basis for local authorities to impose resource consent conditions requiring land to be rehabilitated to approved uses during and after mining.

Jan 1, 1997

By D. W. Fuerstenau

In 1940 Schuhmann1 showed that the size distribution of a comminuted material can be expressed by the following empirical relationship: y = 100 (|f [i] where y is the cumulative percentage of material finer than size x, k is a size modulus, and a is a distribution modulus which is constant for a given material and machine. During the past few years, considerable emphasis has been given to the investigation of the extent of size reduction resulting from the expenditure of mechanical energy in crushing and grinding. Recently Schuhmann' presented a derivation of the energy-size reduction relationship by postulating that comminution in a device such as a ball mill can be considered to be the summation of many single comminution events, each of which yields a size distribution of particles following the Schuhmann size distribution equation. By grinding

Jan 1, 1961

By Walter E. Duncan

The ores treated at the concentrating plant of the Mahoning Mining Co. at Rosiclare, III., come largely from the blanket replacement deposits of the northeastern part of Hardin County, Illinois, and consist of complex mixtures of galena, sphalerite and fluorspar in a gangue of quartz, limestone and sandstone. The several minerals are so intimately inter-grown that they are not liberated at the sizes usually treated by gravity concentration in the usual fluorspar plant. For this reason, an all-flotation method of concentration was developed in cooperation with the station of the U. S. Bureau of Mines at Rolla, Mo.1 This flotation separation made possible the commercial production of four concentrates: (I) lead, (2) zinc, (3) acid-grade fluorspar and (4) metallurgical-grade fluorspar.2,3 Although fluorspar had been floated in Canada in 1921 and a plant at Rosiclare had been floating fluorspar since March 1929, fluorspar flotation was given considerable impetus by the Mahoning developments, since some features of the separation were quickly adopted by other fluorspar companies. The Bureau of Mines6 reports that in the 10 years preceding 1938 only 50,552 tons of fluorspar flotation concentrates were produced in the United States. The rise from this almost nominal figure to 153,750 tons (largely acid grade) in one year (1944)6 is indicative of the activity in fluorspar flotation occasioned by the war. The industry thus proved to be in a position to expand and keep up reasonably well with the requirements imposed upon it by such developments as occurred in high octane aviation gasoline alkylation, in the use of Freon as a refrigerant and as carrier in the Aerosol "bug bomb," and in the atomic bomb project as well as in the expansion of other activities requiring hydrofluoric acid; for example, the aluminum industry. Despite the fact that the greater portion of acid-grade fluorspar produced in the last few years went directly into war uses, the future of the acid-grade field still appears bright. As a result of the activity in fluorine chemistry during the war, it seems likely that in the relatively near future almost every phase of human endeavor will find some fluorine compound involved. The other three concentrates produced deserve some attention in these introductory remarks. The lead concentrates first produced contained both zinc and fluorspar but these did not interfere with their marketing. As will be pointed out later, the quality has steadily improved until today it is a relatively high-grade product. Although some zinc smelters accept concentrates containing limited quantities of fluorspar, it is a very objectionable impurity. Since flotation methods fail in the complete removal of the fluorspar, chemical methods were developed for

Jan 1, 1947