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By R. A. Beall

This bulletin reviews the historical background of the cold-mold arc-melting technology, with specific references to the development that led to homogeneous zirconium ingots. Descriptions are given of modern production arc-furnaces for vacuum melting of troth exotic and conventional metals. Besides zirconium, specific data are given for production of chromium, thorium, and copper. The development of the skull-casting technique for titanium is detailed, and the application of the technique to such refractory metals as molybdenum and tungsten is described. Factors of operation of the apparatus and furnace design are considered.

Jan 1, 1968

By Patrick R. Taylor

In the search for the development of more "environmentally friendly" and more intensive waste disposal approaches to meet more and more stringent environmental regulations, thermal plasma-based processes are considered one of the most promising alternatives to well- established technologies such as incineration. This paper presents an overview on the research and development status of thermal plasma-based waste remediation technologies. The properties of thermal plasma are described. Due to its unique feature of high-energy intensity and super high temperature, thermal plasma is particularly capable of destroying organic- containing wastes. Its potential and promising application to waste remediation may include: treatment of incinerator ashes; metallurgical dusts (especially, electric arc furnace dust); medical wastes; radioactive wastes; and other Resource Conservation and Recovery Act (RCRA) listed hazardous wastes. Many research institutes and vendors have been involved in the development of thermal plasma-based waste treatment technology encouraged by the cleanup programs supported by the Environmental Protection Agency (EPA), the Department of Energy (DoE) and the Department of Defense (DoD). More recently, thermal plasma-based waste treatment technologies (sometimes called plasma-enhanced pyrolysis) are focused more and more on not only just destroying organic wastes but also on how to practically, and economically recover energy contained in the organic waste materials in addition to the recovery of metals in order to offset the high operating costs.

Jan 1, 2003

By Robert C. Dyni

The use of techniques and equipment designed to pneumatically place backfill into an underground mine opening through boreholes for subsidence abatement has historically met with limited success, largely due to the inability to directly monitor the placement of the backfill in the opening. The success of a backfilling project cannot be guaranteed if it is not known whether the underground opening has been completely filled with backfill material. To overcome the inability to directly monitor backfill placement, the U.S. Bureau of Mines developed a pneumatic backfilling system that allows for direct viewing of the backfill as it is placed in an underground mine opening. This system utilizes a recently developed pneumatic nozzle coupled with an instrumentation package that allows for real-time observations and measurements of backfill placed in an underground opening through a borehole. The nozzle utilizes a high-velocity airstream to redirect backfill falling through a pipe in the borehole and directly in front of the nozzle; the airstream redirects and propels the backfill horizontally into the .mine opening at over 100 ft/s. The instrumentation package, mounted directly to the nozzle, contains a video camera, high-intensity lamps, laser-rangefinder, electronic compass, and water sensor.

Jan 1, 2010

By Nathan P. Schmidt

Climate and hydrology data are required during all phases of mining projects, including impact assessment, mine planning and design, operational water management and mine closure and reclamation design. In the Canadian north, data sources are spatially sparse and often short-term in nature, and design parameters are often estimated based on data collected at sites far distant. Confidence in such data can be increased by verification or modification using data collected during properly implemented baseline and operational monitoring programs. A data set that accurately reflects conditions at the project is more readily accepted by regulatory agencies during the permitting process, and allows development of more effective and economic water management, mitigation measures and compensation. Data requirements and collection methods for developing an adequate data set for mine development are reviewed. These are illustrated using examples from oil sands, diamond and metal mines in the Canadian north.

May 1, 2004

By James Westfield

This publication covers the work of the Division of Coal Mine Inspection, Bureau of Mines, as performed under provisions of the Federal Coal Mine Safety Act. It presents background information and data since 1952 when the Act became effective and includes up-to-date statistics for the calendar year 1962. During that year, approximately 9,704 coal mines were active in the United States, and the Bureau made 12,810 regular inspections. BACKGROUND The Federal coal-mine inspection program was established to carry out the provisions in Public Law 49, 77th Congress, (H. R. 2082) approved May 7, 1941. This act has since been amended as Title I, Advisory Powers Relating to Health and Safety Conditions in Mines, under Public Law 552, 82d Congress, approved July 16, 1952, which also included Title II, Prevention of Major Disasters in Mines. Public Law 552 is known as the Federal Coal Mine Safety Act.

Jan 1, 1963

By Pamela J. Watson

A novel technique has been employed by the U.S. Bureau of Mines to determine the zeta potential of particles for a far-reaching series of material types in a wide variety of baseline waters, both alone and with many different chemical additives. The materials tested ranged from naturally occurring Sioux Quartzite and Tennessee marble to commercially produced magnesium oxide bricks. The waters tested ranged from ultrapure distilled, deionized water to municipal tap water and mine-site water. The chemical solutions tested included inorganic additives, such as aluminum chloride (AICI3) and sodium chloride (NaCl); organic additives, such as dodecyltrimethyl ammonium bromide (DTAB); and nonionic polymers, such as polyethylene oxide (PEO). The results of precise zeta potential determinations have application in a large number of laboratory studies as well as in various mining and processing operations.

Jan 1, 1989

By M. E. Rossi

Reconciliation of production information is critical to evaluating the effectiveness of the predictive models, and to allow for optimization of mining operations. Whether mining open pit or underground, mine-to-mill reconciliations can be one of management's better tools to perform proper accounting, and a very useful evaluation and optimization tool. This paper proposes a set of criteria and objectives for a typical reconciliation program; also presents a stepwise, logic approach to performing reconciliations, and discusses the benefits and costs associated with the up-keeping of the information. It also highlights some of the potential pitfalls involved, and methods used to avoid collecting misleading information. These issues are illustrated with an example of a model-to-mine-to-mill reconciliation program being implemented at an operating mine; the program involves multiple predictive models (Long-term and Short-term block models), different open pit and underground mines, stockpiling, and at least 23 different mill streams. This paper presents the initial results of the program implemented at Minera Michilla S.A.

Jan 1, 1999

By Armando Vazquez

When water enters the EAF, some chemically dissociates to H2 while some remains as H2O vapor. Depending on operating conditions the levels of combustible gases (CO and H2) and H2O are continually changing throughout the course of any individual heat and on a heat-toheat basis. The EFSOP® system has been implemented in more than 80 installations as a powerful tool to reduce furnace operation costs but with water detection technology the off gas technology is a valuable solution to improve safety. This paper describes the latest results when using Tenova Goodfellow’s new standalone water detection technology that for the first time provides real-time analysis of both H2O vapor and H2 from start-to-end of a heat. It involves a newly designed water cooled probe and heated line that eliminates condensation during off-gas sampling and an analyzer equipped with a proprietary system for analyzing both H2O vapor and H2.

Jul 30, 2018

By Ailton S. Ferreira, Rubén J. Sanchez Rodriguez, Sergio N. Monteiro, Felipe Perissé D. Lopes, Teresa E. Castillo

"Polyester composites reinforced with natural lignocellulosic fibers have, in recent times, been gaining attention in engineering areas as lighter and cheaper alternatives for traditional composites such as the ""fiberglass"". One of the strongest, the curaua fiber, is today being considered as reinforcement of composites for automobile interior parts. In fact, several research works are currently being dedicated to curaua fiber composites since physical and mechanical properties are required for practical uses. In this work, the thermal behavior of polyester composites reinforced with up to 30 % in volume of curaua fibers was investigated by differential scanning calorimetry, DSC. The results showed endothermic and exothermic events associated with water release and possible molecular chain amorphous transformation. Comparison with similar composites permitted to propose mechanism that explains this DSC thermal behavior.IntroductionThe modem composite materials, especially those reinforced with synthetic fibers such as glass and carbon, have been used since last century to attend the demands required by most technological fields, from home appliances to aerospace [1]. In fact, fiber composites offer significant advantages over monolitic materials, such as common metallic alloys, plastic and ceramics. One of the most important is the ratio between the ultimate stress and the density, known as the specific strength. For example, in common glass fiber polymer composites, the so called ""fiberglass'', the specific strength of around 400 MPa.cm3/g is higher than any conventional monolitic material. However, drawbacks exist. The energy required to fabricate ""fiberglass"" generates large emissions of C02, which are responsible for global warming. Moreover, ""fiberglass"" is not recyclable and cannot be incinerated [2]. As a result, most synthetic fiber composites end up in landfills or contribute to rivers and oceans pollution."

Jan 1, 2011

By David A. Hall

We present an analysis of the propagation in a uniform tunnel of semi -circular cross section that contains two axial conductors. In particular, we show that, even if one of these conductors has high ohmic loss, one of the two propagating modes has relatively low attenuation. This corresponds to the situation where an unloaded dedicated wire is used to improve radio frequency communication in a mine tunnel that contains a heavily loaded trolley wire.

Jan 1, 1978

By K H. Esbensen

Optimisation of a real-time at-line monitoring system for control of industrial granule coating quality is presented. The system is based on a fluorescence imaging system, because fluorescence originates in the interiors of enzyme granules but is significantly quenched by a polymer coating (which is needed due to environmental precautions). We have developed an image analytical system for direct prediction of coating quality, which is based on application of the Angle Measure Technique (AMT) for image complexity characterisation; AMT is briefly described. The first part of the presentation addresses pixel sampling strategies within a digital industrial image, inherent in application of AMT, in which the unfolded image is regarded as a one-dimensional object in analogy with 1D process sampling in Theory of Sampling (TOS). The effects of random, stratified and systematic pixel selections in the unfolded image are evaluated. Also factors such as the fraction of image pixels and the effects of specific unfolding strategies (there are three principal strategies, termed æchopÆ, æsnakeÆ and æspiralÆ respectively) are investigated. It turns out that unsuspected artifacts are sometimes produced, related to the specifics of the unfolding procedure, which interferes with a straightforward 1D TOS process sampling analogy. These artifacts have a wider interest û among others, for 2D sampling û and therefore receive special attention in this presentation. The optimal pixel selection strategy for the AMT algorithm is found to be systematic or stratified sampling (not surprising according to TOS) of 500+ initiating points, but need to be unfolded in the novel spiral- or snake-wise fashions in order to effectively counteract these artifacts. This also has a general impact on various suggested standard schemes for 2D grid-sampling, among others, from the geoscience realms. The second part of the presentation is directed towards optimal image analytical sampling of a continuous series of fluorescent images (imaging of conveyor belts of æinfinite lengthÆ), ie optimisation of process image sampling. The minimum number of images needed to uphold a sufficiently good on-line estimate of the quality control (QC) parameter in question is found to correspond to the relatively high sampling rate of 15 - 20 per cent, which can be shown to be related to an intrinsic very high measurement error level (25 per cent) of a mandated analytical reference method.

Jan 1, 2005

By C V. Deutsch

"Geometallurgical variables often cause problems to conventional geostatistical workflows. There are many variables; some are compositional and some are non-additive. They often show: complex multivariate relationships undersampling relative to conventional grade variables unequal sampling; that is, all variables are not available at all data locations.A variety of approaches have been developed over the years, but geostatisticians remain mostly focused on modelling rock types and a few grade variables with an abundance of data. The problems are reviewed and a chained workflow is presented where appropriate techniques are employed in sequence to permit reliable spatial prediction of geometallurgical variables. The spatial models may be used to assess the value of additional data, for prediction of process performance, for improved mine planning and other optimisation tasks. The chained workflow will include data transformations such as ratios and normal scores that make the variables amenable to geostatistical modelling. Data imputation techniques to account for missing values are considered with special consideration to spatial correlation with the available data. Decorrelation techniques such as the principal components, min/max autocorrelation factors and projection pursuit multivariate transformation are employed to manage massively multivariate modelling. Full distribution modelling must be considered to avoid biases in the prediction of non-additive variables. The post-processing of geometallurgical models must be streamlined for robustness and efficiency. The precise workflow varies according to the specific purpose of the study. Guidelines and thoughts on best practice are presented.CITATION:Deutsch, C V, 2013. Geostatistical modelling of geometallurgical variables - problems and solutions, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 7-16 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

By Tracey Brommer, Britt Elin Gihleengen, Elsa Olivetti, Randolph Kirchain

"Increased demand resulting from the economic and environmental advantages of recycling secondary materials has constrained secondary material supply. As a result of constrained supply, the conventional strategy to maximize recycled content in an individual aluminum alloy must be expanded to maximizing total recycled content in a given production period. This work compares the performance over a two week period of an actual remelter for two strategies; a sequential charge-by-charge optimization framework and an integrated approach that explicitly incorporates the production schedule. Optimizing across the entire two week production is found to increase recycled content and minimize primary and alloying material additions. It is expected that as the scrap material market continues to be constrained by high demand, longer term batch planning strategies that can optimize material allocation will deliver improved performance.IntroductionIntensifying economic and environmental pressure to incorporate secondary aluminum into products is pushing remelters to explore additional strategies and tools to increase recycled content. Aluminum remelters are exploring alternative sources of secondary materials because of constrained secondary material supply and relatively high primary and secondary material cost [1]. Computational models, such as blending models are a tool that could help industrial remelters mitigate supply and cost challenges and thereby increase recycled content. In particular, computational tools can help manage the incorporation of new raw materials of variable quality. Blending models find many industrial applications and have been explored for over sixty years originating with the classic nut-mix problem dating back to 1950’s [2]. Blending models optimize the raw material input to make a desired product subject to a series of constraints such as product specifications and material availability. Deterministic and linear blending model formulations are presently implemented in some industrial aluminum remelters [3]. The primary reluctance of aluminum remelters against computational model implementation is the incapability of their blending models to reflect the intricacy of industrial remelting conditions [4]. For example, to reduce calculation time, industrial aluminum blending models usually optimize a batch plan for a single alloy and are not formulated to optimize several products simultaneously. Since such a model does not include knowledge of subsequent charges in the optimized batch plan, the resulting batch plans tend to deplete the “cleanest” secondary materials leaving the more uncertain and compositionally challenging materials for later charges. As a result, a remelter may override the calculated batch plan or leave certain scrap materials out of the material input to conserve these materials for alternative products scheduled for later production. This work explores an alternative aluminum charge planning tool that can optimize across an extended production schedule and compares it to a heuristic sequential optimization strategy reflecting an industrial remelter."

Jan 1, 2012

By J. J. deBarbadillo

This Bureau of Mines report describes a process for recovering chromium and other metals from superalloy scrap. Laboratory-scale experiments were conducted to test a complex flowsheet utilizing a wide range of extractive metallurgical operations. The novel basis for the process is the fonnation of a sulfide matte in which chromium is concentrated in a discrete chromium sulfide phase. Mineral processing and hydrometallurgical procedures are used to separate chromium sulfide from the other matte constituents. The products of the process are a chromium-nickel alloy suitable for reuse in the superalloy industry, electrolytic nickel, electrolytic cobalt, and iron-molybdenum residue. Recovery of the principal elements contained in the scrap is chromium--93 percent, nickel--99 percent, cobalt--96 percent, and molybdenum--92 percent.

Jan 1, 1981

While there have always been mining activities on the outcrops of the copper deposits around Tsumeb, large scale mining activities in Namibia only started in colonial times. Originally focusing on the known deposits, the then German Geological Survey and independent geologists soon discovered significant deposits all over the country. This eventually lead to intensive mining operations all over the country on copper, gold, diamonds, fluorspar and finally uranium. Ever since those days, mining has been one of the major economical factors of Namibia?s development, as shown in picture 1. In the Central Namib Desert mining on base metals started in 1901, and first uranium deposits were discovered as soon as 1910, later followed by others, this did, however, not lead to any mining activities on those uranium deposits in the following decades. [ ] The upswing in the use of nuclear energy in the 1960s and early 1970s triggered some extensive uranium exploration worldwide and also in Namibia. Several airborne radiometric overviews were conducted by the Geological Survey at this stage and eventually the first uranium mine was commissioned in 1976. In the following three decades, the focus of prospecting activities in Namibia shifted away from uranium again. However, since 2000 the forecast for a developing and growing global economy and its even stronger growing energy demand have triggered a large number of nuclear energy projects worldwide, thus increasing the installed nuclear energy generation capacity from 387 GW today to more than 490 GW in 2025.

Jan 1, 2011

By ALICE V. Petar

Like many gem materials, amber has a colorful history which may be traced through the writings of the ancients and the ornamental relics discovered from time to time. Like few gem materials, however, it is distinctly useful in products whose value has no connection with the gem industry. Long prized for its beauty, amber was fashioned into articles of jewelry and ornaments to please the fancy of ancient rulers and to find a place among treasured pos- sessions in their tombs; it has been used by adherents of various creeds for rosaries and other religious symbols; and although still sold for these pur- poses it also lends itself to such commercial purposes as raw material for varnish. Amber is only on the border-line of the mineral kingdom; actually it is of vegetable origin, having been formed as resin from trees of the conifer family that existed during the Tertiary period. It is the hardest of the fos- sil gums. The United States produces no amber, although a few occurrences are known. Most of the world's supply comes from East Prussia, where it is ob- tained from both land and sea. For many years pieces of amber were gathered from the Baltic by fishermen and deep-sea divers; and although about 10 per- cent of the Prussian amber is still recovered from the sea, most of the out- put is mined from open pits on the Samland Peninsula.

Jun 1, 1934

By Yousef Mohassab, Hong Yong Sohn, Mohamed Elzohiery

As part of the development of a novel flash ironmaking process at the University of Utah, a labscale flash reactor was used to produce iron directly from iron oxide concentrate. This work tested the feasibility of the novel flash ironmaking process using the partial combustion of hydrogen as fuel and reductant. In this flash reactor, the energy required to reduce concentrate particles was obtained from the internal combustion of hydrogen and oxygen with complementary energy from electrical resistance heating to compensate for the heat loss. After the reaction shaft was electrically pre-heated, hydrogen and oxygen streams produced a non-premixed flame inside the reaction shaft. Various conditions such as flame configuration, flame power, positions of concentrate feeding ports, excess hydrogen amount and residence time were tested. More than 90% reduction of magnetite or hematite was achieved at temperatures as low as 1175 oC with < 100% excess hydrogen in <10 s of residence time.

Jan 1, 2016

By H. William Zeller

The Bureau of Mines is conducting research to determine whether the use of chemical surfactants improves respirable coal dust control and is evaluating laboratory test criteria for selecting effective surfactants. This publication presents the results from wetting effectiveness tests with emphasis on the capillary rise test. The test variables investigated included coal particle size, type of surfactant, surfactant concentration, test duration, and mineral con-tent of the water. In addition to the rise test, measurements of con-tact angle, zeta potential, and sink time for various coal and surfactant combinations were conducted. No significant correlations among the four wetting tests were observed, a surprising result which implies that each test type measures specific aspects of the wetting phenomenon and also that each test type should only be used to select surfactants for specific applications. For example, the rise test shows solution penetration into porous materials, and the sink test discriminates among surfactants for dispersing finely ground materials into suspension. Another important conclusion is that combinations of agents retain their individual wetting properties, allowing mixtures to be for-mulated to perform well in both rise and sink tests.

Jan 1, 1983

By R. A. Bloomfield

This report summarizes Bureau of Mines contract research on the disposal of retorted oil shale. A data base has been developed describing the physical-chemical properties, geotechnical engineering properties, and natural cementation characteristics of spent shale. Results of field compaction tests and seepage pond tests are presented, along with results of a partially saturated finite element seepage model used to predict infiltration and seepage rates. Preliminary engineering analyses are presented for underground disposal systems, which include material transport methods, and for a surface disposal system, which includes stability analyses.

Jan 1, 1981

By John Kostuik

"This paper discusses the outlook for uranium resources, and comments briefly on the measures needed to meet market objectives. Areas of recent exploration interest are also discussed.THE PREVIOUS SPEAKER has capably described the truly phenomenal growth in demand for energy from all sources. The basic factors -population growth and industrial development -which will create energy demand are so fundamental to national economies that the ascending energy demand curve will be little affected by short-term factors.Because of the economic and practical advantages of nuclear power and the degree of present acceptance by electric utilities, there is no doubt that uranium will be a principal source of primary energy in industrial countries -and this will happen within a decade. Indeed, during this period it will be the fastest growing source of energy, capturing, for example, more than half of the electric utilities' expansion in the United States by 1980. The ready availability of energy sources from domestic and foreign resources is so essential to industrial nations that the long-range outlook for their adequacy is of prime importance. There has been international concern about the availability of uranium resources at reasonable cost to adequately support and foster the development of the nuclear power industry. Canada, fortunate in having established reserves and a potential in excess of any forseeable domestic demand, can confidently look forward to being a principal supplier to the industry."

Jan 1, 1969