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By Lawrence Melis

Fission Uranium Corp.’s Triple R Uranium Deposit at its Patterson Lake South Project is located in northwest Saskatchewan in Canada’s Athabasca Basin. As part of pre-feasibility studies for the project a detailed metallurgical test program was completed to provide process design criteria. The testwork program encompassed preparation and analysis of test composites, comminution testing, uranium acid leaching, liquid-solid separation, solvent extraction of uranium, precipitation of uranium yellowcake products, tailings and effluent treatment, tailings physical and chemical characterization, and environmental testing of prepared tailings, as well as investigations of gold and silver recovery from the mineralization. The paper provides mineralogical information, testwork methodologies and test results which were used to arrive at process design criteria and the selection of the process flowsheet for the project.

Jan 1, 2020

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 Lorrie Fava

Two needs in the mining industry, to enable overall process improvements, are open systems and network connectivity in underground mines. The Pando project, a collaboration between Symboticware, Vale and Xstrata Nickel, and supported by CEMI, addresses these issues, and leverages the solution platform to deliver intelligent applications. An open system is one that uses publicly available standards for its key interfaces. Vendor-neutrality and ease of information flow are two main benefits that result from the use of open systems. By facilitating the interoperability of systems, open systems allow information to be available when and where it is needed for decision support. Network connectivity in underground mines is typically limited, with hotspots in strategically chosen areas that are relatively static. Mobile equipment moving through a mining work cycle experiences intermittent connectivity; in this situation, seamless remote equipment monitoring is impossible. The Pando project establishes an open technology platform, adhering to the IREDES and OPC UA standards. It enables the collection and integration of information generated by mobile equipment? seamlessly while there is a network connection, and as a store-and-forward gateway to manage intermittent connectivity. The platform capabilities are leveraged to support embedded intelligent applications. This open platform, the SymBot, is a rugged hardware and software device. The platform complies with open standards for industrial automation and systems interoperability. The SymBot platform is capable of providing advanced real-time decision support at the device level, and is designed to be remotely configurable. Applications being developed through the Pando project include engine monitoring, a dynamic load weighing system, machine location monitoring and automated activity monitoring including production and maintenance reporting.

Oct 1, 2010

By D. G. Leddy, J. B. Johnson, L. D. Gratz, S. T. Bagley

"Studies have been conducted at Michigan Technological University (MTU) for over twenty years on methods for characterizing and controlling particulate emissions from heavy-duty diesel engines and die resulting effects on regulated and unregulated emissions. During that time, control technologies have developed in response to more stringent EPA standards for diesel emissions. This paper is a review of: 1) modem emission control technologies, 2) emissions sampling and chemical, physical and biological characterization methods and 3) summary results from recent studies conducted al MTU on heavy-duty diesel engines with a trap and an oxidation catalytic converter (OCC) operated on three different fuels. Control technology developments discussed are particulate traps, catalysts, advances in engine design, the application of exhaust gas recirculation (EGR) and modifications of fuel formulations. Methods for dilution tunnel sampling, particle size analysis, chemical analysis with emphasis on polynuclear aromatic hydrocarbons (PAH) and nitro-PAH, and biological characterization using mutagenic activity (Ames) assays are described, along with statistical approaches to experimental design and data analysis.In studies at MTU, both particulate traps and an OCC have been shown to be effective for the reduction of total particulate mauer (TPM), with the OCC being better al reducing all forms of hydrocarbon emissions, including PAH and nitro-PAH, and with the traps being better at removing the solids (SOL). The use of low sulfur fuel (0.Ql % by mass) has led to additional reductions in TPM; the low sulfur fuel has been shown to reduce the number of small, nuclei-mode particles for one of the engines tested. PAH, nitro-PAH, and mutagenic actively levels generally decreased with use of either the traps or the OCC.INTRODUCTIONDuring the 1980s and the early 1990s there have been significant advancements in the development of technology to control diesel particulate emissions. Efforts have been focused on internal control of the engine by design, the use of after-treatment devices, and improvements in fuel formulations to reduce all the diesel emissions. The research and development activities have been driven by the need to meet the US EPA heavy-duty vehicle standards shown in Table 1. The important standards for new technology are the 1994 heavy-duty vehicle 0.1 gm/bhp-hr particulate, the new urban bus 0.05 gm/bhp-hr particulate standard for 1996 and the heavy-duty vehicle 4.0 gm/bhp-hr NOx standard for 1998."

Dec 1, 1995

By G. du T. Judeel

An investigation was carried out to determine whether a numerical model could be constructed that would produce results that realistically represent actual ground deformations in and around a vertical shaft. The ground deformation was brought about by the partial extraction of the shaft pillar. A special characteristic of the rock masses, affected by the shaft pillar extraction, was that the shaft was located in poor quality rock masses. After the extraction of a portion of the shaft pillar, excessive deformations occurred at the shaft/reef intersection. Therefore, a decision was taken to extract the entire shaft pillar protecting the shaft by a proposed waste-cut across the shaft. The effects of stress and displacement on the shaft were investigated by using inelastic numerical modelling in different stages. A calibrated numerical model was constructed producing modelled results comparable to the actual displacements along the shaft. Des recherches ont été poursuivies pour déterminer si on pouvait construire un modèle numérique qui donnerait des résultats représentant avec réalisme les déformations réelles du terrain à l’intérieur et autour d’un puits vertical. La déformation du terrain était entraînée par l’extraction partielle du massif de protection. Une caractéristique spéciale des masses rocheuses, affectées par l’extraction du massif de protection, était que le puits était situé dans des masses rocheuses de qualité inférieure. Après l’extraction d’une portion du massif de protection, des déformations excessives se sont produites à l’intersection du puits avec le filon. Par conséquent, la décision a été prise d’extraire le massif de protection en entier par une coupe de déblais à travers le puits. Les effets de contraintes et décalage furent étudiés en utilisant une modélisation numérique inélastique à des stages différents. Un modèle numérique calibré fut construit, donnant des résultats modelés comparables aux décalages réels le long du puits. Eine Untersuchung wurde durchgeführt um festzustellen, ob ein numerisches Modell konstruiert werden könnte, das Resultate produzieren würde, welche realistisch aktuelle Bodendeformationen in und um einen vertikale Schacht darstellen. Die Bodendeformation resultierte teilweise aus der Extraktion des Schachtpfeiler. Eine spezielle Eigenschaft der Gesteinsmassen, beeinflußt durch die Schachtpfeilerextraktion, war, daß der Schacht in Gesteinsmassen geringer Qualität situiert war. Nach der Extraktion eines Teils der Schachtpfeiler, traten übermäßige Deformationen am Schacht/Riff Kreuzungspunkt auf. Folglich wurde die Entscheidung getroffen, die gesamten Schachtpfosten zu extrahieren und den Schacht mittels eines geplanten Verlustschnittes quer zum Schacht zu schützen. Die Auswirkungen des Druckes und der Versetzung auf den Schacht wurden unter Anwendung unelastischer numerischer Modelle in unterschiedlichen Stadien untersucht. Ein kalibriertes numerisches Modell wurde konstruiert, welches berechenete Ergebnisse mit den tatsächlichen Versetzungen entlang des Schachtes vergleicht.

Jan 1, 2003

The global mining industry is perceived to be a world leader in sustainability reporting û with a 2008 Ernst & Young survey placing four mining companies in their top five performers in sustainability reporting in South Africa. There is certainly good evidence to support this finding, but there remain many ongoing issues with respect to sustainability reporting and some important areas for improvement by mining companies globally. This paper begins with a broad (but brief) review of sustainability and the technical basis for reporting against a wide range of typical indicators or measures on the environmental aspects of mining. The various protocols, frameworks or systems are then reviewed, with a particular focus on the Global Reporting Initiative (GRI) and its associated mining sector supplement (including the evolution from environmental to sustainability reporting). A wide-ranging survey of reporting by mining companies is presented, including detailed analysis of 2007 and some commodity sectors over time. Examples of reported data are synthesised and analysed, focusing on their accuracy, consistency and utility for accurate assessment of the life cycle impacts for minerals and metals. A number of areas are identified for improved reporting by all mining companies, including water resources and consumption, energy consumption, process inputs (eg acids, solvents, etc), pollutant emissions, including greenhouse emissions, mine site data (not aggregate company totals) and finally rehabilitation and land status. Given the nature of mining, and considering parallels between æpeak oilÆ and the mining sector, it is critical that the state of sustainability reporting continue to evolve and improve û both in the number of companies using the GRI but also in the level and consistency of data being reported. Overall, the paper presents an important review of the present state of the art in sustainability reporting for mining, and provides a range of insights into ways to help improve reporting in the future for all mining companies.

Jan 1, 2009

A record $19.7 billion in minerals was produced by United States industries in 1963. This was some $800 million above the previous high established in 1962. Preliminary statistics compiled by the U.S. Bureau of Mines show that most metals, nonmetals, and fuels gained both in value and volume of production. The 1963 total represents the largest value increase since 1956 and continues an upward trend begun in 1959. Product.ion and value of all mineral fuels rose, with anthracite registering a remarkable 20% value increase. Nonmetals advanced 591 in value, gains exceeding losses by 213 to 1 among individual commodities. Heavier industrial demand and the settling of labor difficulties were among the factors contributing to increased output of such materials as iron ore, bauxite, molybdenum, lead, and zinc, which accounted for most in€ the growth in metal output. Silver prices continued to rise and, as a result, production value of that metal gained 132,.

Jan 2, 1964

By D. Brand

"The risk management objective of the AMIRA Code of Practice for Metal Accounting has seldom been systematically investigated in the literature up to the authors’ knowledge. Risk is defined in the Australian Standard on Risk Management (AS/NZS 4360:2004), as “the chance of something happening that will have an impact on objectives”. The simplified economic analysis performed in this paper has lead to define “something happening” as measurement non-representativity and “impact on objectives” as NSR loss from the optimal NSR. This has pinpointed a missing link being the establishment of a relation between NSR in flotation plants and measurement representativity. The proposed framework, referred to as the total cost of representativity, answers the previously unanswered question of how much accuracy/reproducibility is fit for purpose in a given flotation plant. Authors readily acknowledge that it is way easier to assess the cost of accuracy/reproducibility than the cost of inaccuracy/irreproducibility. However, this exercise not only answers previously unanswered questions but also establishes an essential link with operational excellence. This paper exposes why such operational excellence could neither be attained nor proved without a state of the art metal accounting system. This should impact not only how metal accounting systems are audited/designed/refactored, but also how flotation plants are designed.IntroductionBecause representative metal accounting is a vital source of information for the financial accounts of a mining/metallurgical company, the need for a code on metal accounting was recognized in 2001 and a team was formed in 2003, under the sponsorship of several major mining houses, to produce such a code. Table 1 exposes the two main objectives of this AMIRA Code of Practice for Metal Accounting."

Jan 1, 2017

By J. Alton Burks

When acoustical materials are used in a mining environment for noise control purposes, they are subject to environmental deterioration from hydraulic fluid, moisture, and dust. These and other factors can cause physical degradation of the material, which can lessen its ability to absorb sound. In this study, the Bureau of Mines measured the sound absorption properties of 16 different acoustical materials after 4 sample treatments: (1) being kept clean and dry (as received from the supplier), as a control or reference standard, (2) immersion in water and draining, (3) immersion in lOO-pct-petroleum-type hydraulic fluid and draining, and (4) exposure in a coal mine. The last three treatments were used to approximate the type of physical degradation that can be experienced in actual use. The impedance tube or standing wave method was used to measure the normal absorption coefficient. It was found that the absorption coefficient of most materials was adversely affected by the retention of either oil or water, with oil having the greater effect. The only class of materials that was affected by neither oil nor water was neoprene foam.

Jan 1, 1990

By E. F. Koppe

The Upper Freeport coal in the Freeport and New Kensington quadrangles, Pennsylvania, varies from a bony streak to a thick coal deposit often exceeding ninety inches, the "Double" or "Thick Freeport". Distinctive basal partings, a central bone layer, and a canneloid top bench may be present. The appearance of a sandstone roof, sandstone rolls, and bony coal at the top of the main coal bench can be anticipated in thin Freeport areas when basal partings are absent. When the two basal partings are present, a shale roof is normal. These effects are correlated with the original topography upon which the coal was deposited. The original depositional high areas tend to coincide with present structural highs. Preliminary data indicate that coal quality, in part, is affected by the deposi-tional setting. In "high" areas, a tendency exists for the main coal bench to contain higher percentages of fusain and mineral matter. Within limits, some-what higher ash fusion temperatures appear to correlate with paleotopographic highs. As a result of these findings, critical examination of the paleotopography and related sediments is indicated in other areas and other coals. The Upper Freeport coal is quite variable both in thickness and composition in the Freeport and New Kensington quadrangles of Pennsylvania (Figure 1). The coal horizon in these quadrangles is marked either by a thin carbonaceous shale bed or by a single bed containing a variable number of partings (binders). The complex coal zone known locally as the "Double" or "Thick Freeport" contains the Upper Freeport Coal Bed at the base; but in addition, it has an overlying bone layer and an upper coal bed occasionally capped with a canneloid layer. The "Thick Freeport" often exceeds 90 inches in thickness, whereas the normal Upper Freeport coal usually varies between 34 and 50 inches.

Jan 1, 1961

7133. Clewell, D. H. The Gravimeter. Prec. and Trans. Texas Acad. Science 1941, Austin, Tex., vol. 25, 1942, pp. 86-88. Static gravimeters, unastatized and. astatized, are considered to be the most practical for oil exploration. One gravimeter is described using a beam whose moment about a pivotal axis is elastically balanced. Magnetic or electric fields are deemed unsatisfactory for balancing gravitational force because they cannot easily be kept constant. The gravimeter described is capable of detecting a change in altitude of 3 inches and a change in latitude of about 150 feet. V. S.

Jan 1, 1944

By B. Haimson

A new loading apparatus was fabricated and used to conduct true-triaxial compression tests on KTB amphibolite, a crystalline basement rock. Tests in dry jacketed samples reveal that the intermediate principal stress has a significant effect on the onset of dilatancy and on rock strength, contrary to the implicit assumption made by Mohr-type failure criteria. Failure is induced through a shear fracture that dips steeply in the direction of the least principal stress. Experimental results lead to a new generalized strength criterion in terms of all three principal stresses. Unjacketed KTB amphibolite specimens, exposed to confining fluid, are considerably weaker than the jacketed ones, despite the negligible porosity and permeability. Failure is facilitated by several closely spaced subparallel tensile cracks normal to the least stress direction. SEM analysis suggests that microcracks developed upon dilatancy onset are penetrated and extended by the confining fluid, bringing about the unexpected rock failure mechanism at reduced stress levels. Un nouveau dispositif à chargement fut fabriqué et utilisé afin de réaliser un vrai essai de compression tri-axial sur KTB amphibolite, une roche cristalline du sous-sol. Les essais effectués sur échantillons enveloppés et secs révèlent que les contraintes principales intermédiaires affectent considérablement le début de la dilatance et la résistance de la roche, contrairement à la supposition fondée sur le critère de rupture de Mohr. La rupture est produite grâce à une cassure de cisaillement très incliner en direction où la contrainte principale est moindre. Ces résultats expérimentaux indiquent un nouveau critère de rupture général en fonction des trois contraintes principales. Les échantillons de KTB amphibolites sans enveloppe, exposés à un liquide confiné, sont considérablement plus faibles que ceux enveloppés, malgré la porosité et la perméabilité négligeable. La rupture est facilitée par plusieurs fissures de traction adjacentes et sub-parallèles, normales à la plus petite contrainte principale. L’analyse SEM suggère que les micro-fissures développent suivant le début de la dilatance, elles sont pénétrées et agrandies par le liquide confiné, produisant un mécanisme de rupture de roche inattendu, ceci à un niveau de contrainte réduit. Ein neuer Ladungsapparat wurde hergestellt um real - triaxiale Druckfestigkeitsversuche in KTB Amphibolit, einem kristallinen Grundgebirgsgestein, durchzuführen. Messungen in trockenen, bedeckten Proben zeigen that die mittlere Hauptspannung eine bedeutende Wirkung auf das Einsetzen von Dilatanz und auf die Stärke des Gesteins hat, im Gegensatz zu der impliciten Annahme auf Grund von Mohr-ähnlichen Versagungskriterien. Versagen ist induziert durch eine Scherfraktur die sich steil in die Richtung der geringsten Haupspannung nach unten senkt. Messergebnisse führen zu einem neuen, verallgemeinerten Stärke Kriterium dass auf alle drei Hauptspannungen basiert ist. Unbedeckte KTB Amphibolit Proben, die unmittelbar den umgebenden Fluiden ausgesetzt sind, sind wesentlich schwächer als bedeckte, trotz geringfügiger Permeabilität und Porosität. Versagen wird gefördert durch mehrere, nebeneinander liegende, sub-parallele Spannungsbrüche, normal zu der geringsten Spannungsrichtung. SEM Analyse lässt vermuten dass Mikrobrüche, die sich beim Überschreiten der Dilatanzschwelle entwickeln, durch die umgebenden Fluiden fortgepflanzt und weiter verbreitet werden, und unerwartet, auf Grund der reduzierten Spannungswerte, den Versagungsmechanismus des Gesteins einleiten

Jan 1, 2003

By Enzo Palumbo, Joël P. T. Kapusta, François Larouche

In light of the rapid deployment of bottom blowing smelting in China over the last ten years, one has to wonder why it has taken the copper industry so long to adopt ultra-high oxygen enrichment via Savard-Lee type injectors. As early as 1976, Kellogg and Henderson suggested, in their landmark paper on energy usage in the copper industry, that ‘maximum use of oxygen enrichment of process air’ was one of seven ‘energy saving features’ for copper matte smelting and converting. Yet today, shrouded injection and high oxygen enrichment has not been implemented in copper bath smelting outside China and Vietnam. In this paper, the authors explore the reasons why bath smelting processes such as the Noranda Reactor and the Teniente Converter still operate around 40% oxygen enrichment, while the bottom blowing SKS/BBS process typically runs at 65 to 75% oxygen, with all three processes producing white metal. Are there fundamental metallurgical explanations for this striking difference beyond the long-standing skepticism towards high oxygen shrouded injection and its perceived high implementation cost?

Jan 1, 2015

By Marco Barla, Mariacristina Bonini, Giovanni Barla

ABSTRACT: The paper describes the characterisation studies of Tectonised Clay Shales at laboratory and in situ scale. The interest relates to tunnelling under squeezing and swelling conditions, in Italy, along the Apennines. The results of monitoring during full face excavation are presented in conjunction with numerical modelling. RESUME: Cet article présente la caractérisation, à l'échelle du laboratoire et in situ, des Argiles Chaotiques. L'attention est portée sur le creusement, dans ces milieux gonflants, des tunnels, dans les zones montagneuses des Appennini, en Italie. Enfin, on présentera les résultats de la modélisation numérique et la comparaison de ces derniers avec les mesures effectuées in situ. KURZFASSUNG: Die Arbeit beschreibt die Charakterisierungsstudien von tektonisierten Schiefertonen, sowohl im Labor als auch vor Ort. Das Interesse gilt dem Tunnelbau unter Quetsch- und Schwellbedingungen in Italien entlang der Apenninen. Die Überwachungsergebnisse des ganzflächigen Ausbruchs werden mit numerischen Modellen präsentiert.

Jan 1, 2003

By T. R. Ellis

"Editor’s Note: This is an expanded abstract. The full report is available on SME’s website at http://www.smenet.org/publications-resources/ resources/sme-valuation-standards-tutorials.The author has three goals for this review of mineral valuation standards internationally.1. To place the SME Standards and Guidelines for Valuation of Mineral Properties (SME Valuation Standards) and International Mineral Property Valuation Standards template (IMVAL Template) within the global context of existing mineral valuation standards.2. To review the current status of harmonization of each International Mineral Valuation Committee (IMVAL) member’s mineral valuation standards (or code) with the IMVAL template and suggest remedies for issues found.3. To suggest future enhancements for the IMVAL Template and SME Valuation Standards, and to suggest future roles for the IMVAL and SME committees. From the author’s review, Ellis draws the following conclusions.The SME Valuation Standards comprise a minimum set of principles-based standards and guidelines for developing and reporting valuations of mineral properties (including petroleum properties) for public and private use, subject to jurisdictional requirements. The standards are also designed to provide mineral valuation guidance that supplements application of the International Valuation Standards Council’s International Valuation Standards (IVS) and the U.S. government endorsed Uniform Standards of Professional Appraisal Practice (USPAP), published by the Appraisal Foundation.The SME Valuation Standards is the first set of valuation standards developed by a minerals institute adopting and modifying the IMVAL template. As a result, the SME standards are essentially totally harmonized and otherwise aligned with the IMVAL template. IMVAL was initially conceived in 2012 as a discussion body to aid harmonization of each member’s valuation standards, by modifying to function the same. IMVAL primarily developed the IMVAL template, published in July 2016, to produce an agreed reference framework of essential mineral valuation guidance content as the goal for harmonization of the Australasian Code for Public Reporting of Technical Assessments and Valuations of Mineral Assets (VALMIN Code), The South African Code for the Reporting of Mineral Asset Valuation (SAMVAL) and the Canadian Standards and Guidelines for Valuation of Mineral Properties (CIMVal standards and guidelines). The harmonization would result from each mineral valuation standards committee modifying its standards to operate similarly to the IMVAL template, producing valuation reports with similar content and value for the same mineral property. The template is also available for other bodies to adopt and modify for their regional setting’s needs, as SME did, or use as a convergence goal when updating an existing standard."

Jan 2, 2018

By Mahiyar Nasarwanji, Jonathan K. Hrica, Jonisha P. Pollard, Lydia M. Kocher, Brianna M. Eiter

Within the metal/nonmetal mining sector, fall-related incidents account for a large proportion of fatal and non-fatal injuries. However, the events and contributing factors leading up to these incidents have not been fully investigated. To help provide a clearer picture of these factors, an analysis of imminent danger orders issued by the Mine Safety and Health Administration (MSHA) between 2010 and 2017 at both surface and underground metal/nonmetal mine sites revealed that most orders are associated with fall risks. Of these cases, 84% involved the workers not using fall protection, fall protection not being provided, or the improper use of fall protection. Fall risks for workers most frequently occurred when standing on mobile equipment, performing maintenance and repairs on plant equipment, or working near highwalls. In most cases, a single, basic, corrective action (e.g., using fall protection) would have allowed workers to perform the task safely. Overall, these findings suggest that a systematic approach is needed to identify, eliminate, and prevent imminent danger situations. Furthermore, to protect mineworkers from falls from height, frequently performed tasks requiring fall protection should be redesigned to eliminate the reliance on personal fall protection.

By Manish Kumar Jain

The mineral industry in India is an important contributor to the country?s GDP and foreign trade, and also a significant source of employment generation. The industry is distributed almost all across the country and has operations in some of the remotest areas, where it has also served as a sole source of infrastructure development. India produces 89 minerals, out of which four are fuel minerals, 11 metallic, 52 non-metallic and 22 minor minerals. The mining leases are occupying about 0.21% of the total land mass of the country. Indian mining industry is characterized by a large number of small operational mines (approx 3000 mines). Appropriate systems have been put in place to ensure sustainable growth of the sector, which include formulation of procedures for scientific prospecting and mining and development of a mechanism of prior environmental and forest clearances for mining projects. Main emphasis is to protect the health and safety of mine workers, as well as to safeguard the interests of indigenous people through rehabilitation and resettlement packages. Efforts are under way to mainstream the artisanal and small-scale mining sector in order to promote equity in the mining industry. The issue of scientific closure and reclamation of the abandoned mine sites poses a major challenge. Present paper illustrated several initiatives have been taken in this direction along with case studies, which could be replicated in other parts of the country.

Aug 1, 2013

By L. L. Hirst

Liquid fuel oils possess certain advantages over solid fuels. Ease in handling, precision temperature control, and almost complete freedom from ash are among those considered when a liquid fuel is selected for use in industrial processing. In some instances these fuels are desirable because more heating units can e packed in a Given space where space is limited, as on snips. In other cases the' are chosen because of lower actual cost per British thermal unit absorbed, or for control of the flame to increase the capacity of furnaces, as in steel and refining.

Jan 1, 1948

By G. E. Veins

A three-phase, continuously-operated, 250 kv.a. electric smelting furnace has been installed at the Mines Branch, Department of Mines and Technical Surveys, Ottawa, for the experimental treatment of ores and by-products of interest to the Canadian mining, metallurgical, and chemical industries. In the operation of this furnace particular emphasis is placed on the accumulation of quantitative data which will be useful in determining the most suitable smelting technique and the nature of the products, and in arriving at preliminary conclusions regarding the cast of power and electrodes. The results obtained in the experimental smelting of iron, manganese-iron, titanium- iron, nickel, and chromiumiron ores, and of a number of industrial by-products, clearly show the value of such treatment for materials of this type.

Jan 1, 1957

Face and pillar bursts, bumps and bounces are violent failures that occur in underground coal mines in response to a complicated interplay of face and pillar geometry, seam depth, coal properties and interactions between roof, seam and floor strata. Additional complications arise from the presence of gas, mainly methane, and associated pressure and flow that vary with time and are further influenced by the rate of face advance. Where gas plays a dominant role, the term outburst is often used; where stress concentration is primary, terms such as burst, bump or bounce may be used. Hargraves [1983] presents an often cited review of outburst phenomena with emphasis on Australian conditions. Beamish and Crosdale [1998] indicate outbursts have occurred for over a hundred years and present tabulations of outburst numbers in major coal basins throughout the world. A central consideration is the rate of depressurization that occurs in the course of mining. Outbursts are not limited to coal seams and adjacent strata; they also occur in salt and potash mines [Molinda et al 1988]. Stress concentration and gas pressure act in consort, so the combined action is important to understanding the mechanics of bursts or outbursts and to the development of measures to reduce the associated hazard. Gas flow is a complicated phenomenon associated with diffusion of gas from micro-pores and the flow of gas along cleats. Laboratory measurements indicate both are dependent on stress and pressure [Harpalani and Ouyang 1998]. Moreover, gas permeability in porous media is often many times water permeability [Klinkenberg 1941]. However, there is also evidence that gas and water permeability are similar at elevated stress and follow Darcy?s law [Dabous et al]. Gas flow is also of importance to mine ventilation. Price et al [1973] in cooperation with personnel of the former U.S. Bureau of Mines developed finite difference models to estimate methane emission in mines in the Pocahontas No. 3 and Pittsburg seams using a premining pressure of 4.69 MPa (680 psi) and Darcy's law implying laminar flow. However, the effects of stress were not taken into account. In this regard, mine measurements of permeability are usually based on Darcy?s law [Peide 1990]. Early models of gas flow with stress effects were one-dimensional in space and time (x,t) and were developed with the goal of estimating the gas pressure profile from the face into the seam as time passed [Schlanger and Paterson 1987, Zou and Yu, 1999]. A zone of high permeability adjacent to the mining face was recognized in these early models. Later models based on the popular finite element method allowed two spatial dimensions (x,y) and variation in time (t) and for coal seam heterogeneity [Tang et al, 2002]. Zhu et al [2007] formulated a set of nonlinear equations involving a complicated stress-pressure-permeability relationship for application to coal seam gas flow and concluded the coupling was important but failure of coal should also be considered. Wold et al [2008] used a hybrid finite difference - finite element model interleaved with a reservoir simulation model to study outbursts based on extensive mine and laboratory measurements. An important feature of the modeling was the use of spatially variable material properties and Monte Carlo simulation to obtain quantitative estimates of outburst conditions and probabilities. Connell [2009] used the same reservoir simulation model as Wold but used the popular finite difference code FLAC3D for hydro-mechanical responses to evaluate two permeability relationships, one depending on porosity and the other on stress, and concluded that permeability changes with gas production were more complex than computed by either permeability model. Gadde [2010] in an integrated laboratory and field study of coal pillar strength explored the effect of spatial variability and concluded that design based on average strength was acceptable in some circumstances, although gas pressure was not an issue. Liu et al [2011] also applied a FLAC code to analyze two-dimensional gas flow and deformation of layered but homogeneous strata in a Chinese coal mine using a strain-softening model and concluded that damage and gas pressure were important to strata safety relative to the case without gas.

Feb 27, 2013