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By D. W. Smith, Robert F. Mehl

It has been shown by numerous studies that the orientations of new metal crystals are determined by the orientations of the crystals in the original matrix, whether these new crystals are formed by recrystalliza-tion, by precipitation from solid solutions, or by transitions in the solid state. The orientations of crystals formed by recrystallization of cold-worked metals that bear preferred orientations are occasionally simply related to the initial preferred orientation; often, however, the relationship is not simple, but complicated and obscure in origin.1 The orientations of crystals formed by precipitation from solid solutions have been shown by many studies in this and other countries to be determined by the orientation of the crystals of the solid solution stable at the higher temperatures, though here again complicated cases have been found and no general theory is available.2 Related to this latter class are the relationships found in crystals formed by suppressed transforma-

Jan 1, 1935

By D. W. Smith, Robert F. Mehl

It has been shown by numerous studies that the orientations of new metal crystals are determined by the orientations of the crystals in the original matrix, whether these new crystals are formed by recrystalliza-tion, by precipitation from solid solutions, or by transitions in the solid state. The orientations of crystals formed by recrystallization of cold-worked metals that bear preferred orientations are occasionally simply related to the initial preferred orientation; often, however, the relationship is not simple, but complicated and obscure in origin.1 The orientations of crystals formed by precipitation from solid solutions have been shown by many studies in this and other countries to be determined by the orientation of the crystals of the solid solution stable at the higher temperatures, though here again complicated cases have been found and no general theory is available.2 Related to this latter class are the relationships found in crystals formed by suppressed transforma-

Jan 1, 1935

The Environmental Session will consist of five papers dealing with various aspects of trace elements associated with coal. Analytical procedures to determine the amounts of trace elements will be discussed. Other papers will deal with trace elements in streams downstream from coal mines, potential pollution from wastes from coal preparation plants, potential recovery of trace elements, and potential pollution from trace elements as a result of the combustion of coal.

Jan 1, 1979

By Jean Goldschmidt

Recycling of fine oxidized particles of non-ferrous metals usually cannot be carried out by pyrometallurgical methods. 'Hydrometallurgy provides an alternative technology to reintroduce? the resulting products as secondary raw materials into the industrial cycle, thereby saving resources and energy while keeping the environment a little cleaner. The paper summarizes the methods employed by Hydrometal to achieve these objectives and? stigmatizes the latest counterproductive international regulations which create ever more obstacles to environmentally sound recycling.

Jan 1, 1995

By P. Zhang

The use of phosphate depressants in the cationic flotation of silica from francolite in the Florida phosphate industry is rarely practiced. The occasional use of gelatinized starch derivatives and pH adjustments to assure a slightly alkaline flotation feed slurry pH have been used in some processing plants to improve selectivity. This paper presents a preliminary laboratory comparison of several potential phosphate depressants for use with the flotation of siliceous phosphates. It was found that starch is ideal for floating fine (-35 mesh) silica from phosphate, while sodium tripolyphosphate may be the best for coarser (+35 mesh) feeds.

Jan 1, 2009

By Cesar Carrasco, Heath Arvidson, Mark Forster

Block models built to represent the geology and rock characteristics of mineral deposits represent huge complex data sets, which form the basis of strategic and business planning, and public reporting of Mineral Resources and Mineral Reserves. Recent advances in cloud computing and database technology developed for the Internet of Things offer a different way of working with these critical data sets. Enabling a cloud based, open data structure with high performance data analytics capability presents a compelling improvement in governance and a democratization of ore body knowledge that can lead to automation use cases that support the digitalization of mining.

Jun 25, 2023

By C. Çelik

Nowadays the optical sorting of industrial minerals is one of the most important processing methods which has cost efficient production possibilities. This method is used for industrial and raw materials that have different colour and brightness features. Initially this technology is used for sorting of foodstuffs and recovered glass, but for a long time also as physical mineral processing method for both industrial minerals like: limestone, marble, talc, basalt, flint, quartz and secondary raw materials like: building rubble, refractory materials, glass, plastic and household waste. In this study via optical sorting the separation of quartz out of a flint mix, which consists of the particles with different colors and brightness, is aimed. Experiments are performed on an optical sorting machine named CombiSense® 1200 at the institute of ?Aufbereitung mineralischer Rohs-toffe? RWTH Aachen. This automatic picking device was developed by the company ?Separation Systems Engineering (SSE), Wedel?. Hand picking method is used for product analysis and the efficiency tables are prepared on every step accordingly. This process enables to reach quartz products with purity up to 100%.

Jan 1, 2014

By Richard W. Greene, Joel S. Hirschhorn

MATERIALS containing very large amounts of porosity, in the order of 50 to 90 vol pct, are extremely difficult to evaluate according to conventional mechanical behavior tests. This is usually a consequence of their low strength and brittleness, and the difficulty of preparing standard test specimens. A simple fatigue test has been developed and used successfully on porous nickel sheet materials requiring no specimen preparation; it could also be used for configurations other than sheet or plate. Samples of the sheet. 2 in. sq and about 0.025 in. thick, are placed in a vessel that is evacuated to about 50 f Hg by a mechanical pump. Distilled and deairated water is allowed to enter the vessel thereby filling the porosity (virtually all the porosity in these nickel ma-

Jan 1, 1970

By Oliver Bowles

This report covers the character, properties, origin, occurrence, and uses of the traprocks and describes briefly the methods and equipment employed in quarrying and preparing them for market. Production of traprock occupies an important place in industry. In 1960 the output in the form of crushed stone reached nearly 58 million tons valued at $87 million. Traprocks are also shaped into blocks of dimension stone for monuments, building construction and decoration, and specialized products such as surface plates.

Jan 1, 1963

By Oliver Bowles

This report covers the character, properties, origin, occurrence, and uses of the traprocks and describes briefly the methods and equipment employed in quarrying and preparing them for market. Production of traprock occupies an important place in industry. In 1960 the output in the form of crushed stone reached nearly 58 million tons valued at $87 million. Traprocks are also shaped into blocks of dimension stone for monuments, building construction and decoration, and specialized products such as surface plates.

Jan 1, 1963

By Richard D. Zigmond

In this paper, a computer program that has been developed for determining the capital and operating costs for coal preparation plants is described along with its applications. The logic of the computer program is based upon the results of a survey of existing preparation plants, operators, plant contractors, equipment manufacturers, and consulting firms. This survey provided information on plant performance, order-of-magnitude costs, and costing procedures. Additionally, an extensive cost data file for the major capital equipment in coal preparation plants has been developed. Using the washability data and the computer program outputs, the cleaning costs per million Btu can be calculated. Details about the program and its applications can be found in a report by the authors (Zigmond et al., 1979).

Jan 1, 1981

By Waddah Akili

This paper describes the steps taken in planning, developing, and executing a case study/ case history course in geotechnical/ foundation engineering at an international university. The paper sheds light on: how a “workable” format for the course was arrived at; the organization of the course; and the results of evaluating the effectiveness of this approach versus traditional lecturing. Problems and challenges that could arise when offering the course for the first time are also addressed. Embedded in this experience and its related protocols are: the emphases on engineering design and the practice, teamwork and leadership development, organizational management, and oral and written communication skills. The paper concludes by confirming that discussions, through an open forum, are judged to be superior to traditional lectures in improving critical thinking, cultivating desirable personal attributes, and acquiring problem-solving skills.

By H. Krogerus, P. Niemelä, P. Oikarinen

High carbon ferrochromium is produced by carbon reduction. No replacement for carbon as reductant has yet been developed. The reduction creates a considerable amount of CO-gas. In open and semi-closed furnaces the gas is burned when leaving the burden. In closed furnaces the formed gas is sucked out by a fan, washed and utilised as fuel. The formation of carbon monoxide is presented briefly starting from thermodynamic considerations up to solid and liquid state reduction. The volume, composition and energy content of the furnace gas are discussed, focusing on the raw materials and pre-treatment processes of the furnace feed as well as on the process equipment and control. Outokumpu has been using closed and sealed furnaces and utilising the CO-gas in its Tornio Ferrochrome Works since 1968. Today in Tornio with an annual ferrochromium production of 260 000 t CO-gas production is 186 million m3, representing 68 MWh an hour. At the same time the furnace power input is 95MW. About 98 % of the CO-gas is utilised, whereof 30% in the ferrochrome production itself. This paper focuses on the characteristics and utilisation of CO-gas. CO-gas is secondary energy, which on one hand saves primary electric and fossil fuel energy in ferrochromium production and, on the other, replaces other fossil fuels at the adjacent steel works. The characteristics of the fuel, requirements for utilisation as well as health and safety aspects are discussed. Utilisation of the gas has a high impact on the total dust and gaseous emissions and on the energy optimisation at the ferrochromium and steel works.

Jan 1, 2004

By H. H. Schrenk

[There is a need for method of determining: benzene vapor in air which is simple and accurate and suitable for making industrial hygiene surveys. The most widely used method in this country is the modification of the Elliott and Dalton6/ procedure. This depends on the nitration of the benzene to reduction to phenylenediamine with all excesses of standard titanous chloride; solution, and titration with e standard ferric ammonium sulphite solution. This method has the disadvantages of being what time consulting: and cumbersome it requires considerable apparatus, and a special modification is necessary in the presence of toluene.]

Jan 1, 1935

By D. R. Lentz, J. A. Walker

"Abstract -The Flat Landing Brook Zn-Pb-Ag deposit of the Bathurst Mining Camp occurs within a narrow thrust-bound nappe containing felsic volcanic and volcaniclastic rocks of the Tetagouche Group. Within the host nappe, the Tetagouche Group is represented by the Nepisiguit Falls Formation and the overlying Flat Landing Brook Formation. The Nepisiguit Falls Formation is divided into two members: quartz- and quartz-feldspar-phyric volcaniclastic rocks ± minor lavas (Grand Falls member), and aphyric, fine-grained volcaniclastic rocks (Little Falls member). The Flat Landing Brook Formation consists of aphyric rhyolite flows and interbedded pyroclastic rocks. Several gabbroic intrusions occur in both the footwall and hanging-wall sequences. These gabbros locally cut out the mineralized horizon at shallow levels, and are considered to be feeders to tholeiitic basaltic flows (Forty Mile Brook member) of the Flat Landing Brook Formation. The Flat Landing Brook deposit has many of the characteristics typical of volcanogenic massive sulfide deposits occurring within the highly productive Nepisiguit Falls Formation in the eastern part of the Bathurst Mining Camp. Mineralization occurs within or at the top of the Grand Falls member and comprises four or more massive to semi-massive sulfide lenses that vary in thickness between 3 and 5 m. Massive lenses are laterally gradational to, or underlain by, zones of disseminated sulfides up to 38 m thick. The deposit contains an estimated resource of 1.7 Mt grading 4.9% Zn, 0.94% Pb, and 19.54 g/t Ag to a depth of approximately 150 m. From 150 to 300 m below surface, mineralization is low grade and mostly disseminated. However, below 300 m, ore-grade (>10% Pb+Zn) massive sulfide lenses have been intersected over mineable widths. Oxide facies iron formation overlies and (or) grades laterally into the sulfide lenses. The oxide facies has strong positive Eu anomalies and gently sloping rare earth element (REE) profiles suggesting that it was formed from relatively hot acidic fluids that had interacted with felsic volcanic rocks in the footwall. In contrast, the silicate facies iron formation that is more distal to sulfide accumulations has very weak positive Eu anomalies and gently sloping REE profiles, suggesting either cooler hydrothermal fluids or dilution of the hydrothermal component by detrital material. Hydrothermal alteration has affected most footwall rocks. Most notably, albite-destructive alteration has resulted in Na2O depletion, whereas mass addition of K2O is manifested in the formation of sericite (white mica). In more intensely altered quartz- and feldspar-phyric volcaniclastic rocks of the Grand Falls member, feldspar destruction is accompanied by chlorite alteration, producing quartz-phyric rocks similar to those in the footwall of many Bathurst Camp deposits."

Jan 1, 2006

By S. Badr, R. Mendoza, M. U. Ozbay, M. D. G. Salamon

ABSTRACT: The use of coal pillars at depth is fraught with problems due roof control difficulties and the possible occurrence of coal or pillar bumps. In the USA the largest and most important application of pillars at depth is in longwalling, where chain pillars are the customary supports of the multiple entry developments. At first, the chain pillars were designed using conventional approaches, where the principle is that the strength of the pillar should exceed the load imposed on it. Such approach to design led to larger and larger pillars at great depths, but instead of eliminating, it tended to aggravate the roof control problems. Eventually the idea was born that small sized yielding pillars, which have proved to be successful elsewhere, might provide the answer to this pressing problem as well. The aim of this paper is to study the modes of pillar failure at great depths, using two solution methods. The first of these comprises some elementary solutions obtained with the aid of a simplified conceptualization of the rock mass. This model consists of a strain-softening coal seam sandwiched between two stratified masses. The second approach utilizes FLAC3D, which is a commercially available three-dimensional numerical modeling software package. To gain a better insight, both the strain-softening and ideally plastic Mohr-Coulomb constitutive laws embodied in FLAC3D were exploited. As expected, the width to height ratio of the pillar has proved to be the primary factor that determined the behavior of the pillars. Narrow pillars fail in a stable manner without the occurrence of instabilities. Intermediate w/h ratio pillars under the appropriate loading conditions, may fail suddenly and may even collapse totally. Squat pillars do show the potential for sudden, coal bump like side failure, but because the remaining large width of the inner core, the ruble around the pillar provides sufficient confinement so as to reestablish stability. Finally, the study revealed that the traditional Mohr-Coulomb law does not provide a useful insight into the failure of coal pillars. RESUME: L’utilisation des piliers de charbon dans les mines souterraines de grande profondeur occasionne des problèmes due aux difficultés de control de plafond et possibles fracture ou explosions au niveau des piliers. Aux Etats-Unies d’Amérique, l’utilisation des piliers dans les mines souterraines de charbon comme moyen de support est considèrees comme étant la plus grande et la plus importantes des méthodes utilisée dans le ‘’ longwalling method’’ ou une série des piliers sont disposé de manière à supporter les multiple entrées d’exploitation de charbon. En premier lieu, cette série des piliers étaient construit de manière conventionnelle avec un principe basé sur le fait que le poids exerce sur les piliers doit être inférieur a la force que ces piliers exerce sur le plafond. Ce principe a conduit a ce que le volume des piliers augmente au fur et à mesure que la profondeur au de la mine augmente. Malheureusement, au lieu de résoudre le problème de support, ce principe n’a fait qu’aggraver le problème de contrôle de plafond. Eventuellement une idée s’est dégagé allant du fait que les piliers endommagés de taille moyenne qui se sont avérés être efficaces ailleurs, pourraient fournir un indice à ce particulier problème. Le but de cette recherche est celui d’étudier les différent types de ruptures qu’un pilier peut occasionner lorsqu’il est utilisé a grande profondeur, tout en utilisant deux possible méthodes. La première d’entre elle comprend quelques solutions élémentaires obtenues avec l’aide d’une méthode simplifié et conceptuelle de la masse de la roche. Ce modèle consiste à prendre en sandwich la bande de minerais de charbon entre deux masses stratigraphiques sans pour autant endommager le plafond. La seconde méthode nécessite l’utilisation du ‘’ FLAC3D’’, qui est un logiciel commercialisé disposant d’un modèle numérique en 3 dimensions. Dans le but d’obtenir

Jan 1, 2003

By Elliott A. Pood, Ron Gilbert

Recent advances in digital recording technology have allowed frame rate increases in video recording equipment that provide the capability for super slow motion playback of commercial explosives shots. Such slow motion playback allows for the analysis of shot patterns, cap scatter, pattern failures, etc. In addition, the availability of such materials on video tape enables commercial blasters to provide a means for training current and future staff.

Jan 1, 1996

By M. S. Diederichs, J. Oke

Surface limitations and a need for more direct transportation routes require serious consideration be given to the development of underground construction works in geotechnically unfavourable conditions. Due to geographical and logistical limitations, the construction of these underground works is restricted to difficult ground conditions that require temporary pre-support before excavation in order to avoid tunnel collapse or severe surface settlement. One type of pre-support is the umbrella arch system, which has been gaining popularity due to cost and time commitment in comparison with other pre-support systems (e.g., ground freezing). The umbrella arch system has been employed with significant frequency around the world, yet without a complete understanding about the mechanical response of the system. As such, literature has found the temporary support system to be both under and over designed with regard to safety and/or economical impact. The authors of this paper have made three major contributions to increase understanding of the umbrella arch system and to help optimize the design process. Firstly, the authors have developed nomenclature in order to categorize and define umbrella arch elements and systems, which also stimulated the creation of the empirically driven Umbrella Arch Selection Chart. Secondly, the authors have established a design methodology that is primarily based on advanced numerical modelling techniques to aid in the optimized design of the umbrella arch arrangement for site specific conditions. Thirdly, the authors have developed a semi-analytical model for umbrella arch systems employed in squeezing ground conditions by incorporating elastic foundation theory as well as convergence confinement theory. These three major contributions to such a widely employed tunnelling pre-support system will be introduced and explained in detail, and will include discussion of how each is incorporated in the complete tunnel support design process and throughout the construction and monitoring phase of a project.

Jan 1, 2015

By R. J. Grace

Carbon in the form of coke is used as a reactant in various chemical and metallurgical processes, The high cost of by-product coke along with its periodic lack of availability and high investment necessary for additional by-product recovery facilities indicate the need for a low-cost production unit based on a new procedure for coke manufacture, Traveling-grate coking-stokers were developed by Shawinigan Chemicals Ltd. to produce coke required for carbide manufacture, They were adapted to kilns so that the hot volatile gases could be used for lime burning, Their operation has been described in various patent disclosures (1, 2, 3), and their application to rotary lime burning kilns has been described by Andersen (4). Details of the process and plants have also been published by Kurt Baum (5,6).

Jan 1, 1958

By Eric S. Weiss, Deno M. Pappas, Timothy M. Barton

During the past few years, the Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) has been evaluating developments in sealant support systems from a ground control perspective. The proper selection and use of a sealant material can significantly enhance ground control which may result in a decrease in worker related injuries due to ground falls. The purpose of this paper is threefold: to briefly review the current state-of-the-art technology in shotcrete and membrane developments, to evaluate the preliminary findings of a long-term underground study of various types of sealant materials, and to examine installation practices that are critical for an effective sealant material. The underground study utilizes NIOSH’s Lake Lynn Laboratory Experimental Mine to evaluate the long-term performance of several types of shotcrete and membrane materials. Sealant performance to date have been evaluated on a regular basis over a two year period. Although the study is still ongoing, critical mining practices were identified that may seriously effect the bond of the sealant materials to the mine roof and rib; most notably, the importance of scaling and thorough cleaning of the rib prior to application. Also, results froman extensive series of Schmidt Hammer tests found that the shotcrete increased in strength by 70% during the humid summer months.