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By J. E. Gill

"The name 'Canadian Shield' is used for a vast area; largely in northeastern; Canada; underlain by Precambrian rocks. The part in Canada has an area; of about 1; 790; 000 square miles. Extensions in Greenland; Labrador; Newfoundland; and the United States bring the total area to around 2; 800; 000; square miles. The boundaries of the Canadian part are shown in Fig. 1.; At its margins; the Precambrian rocks can be seen at many places to; extend beneath a cover of flat-lying Palxozoic or later sediments. Information; from borings in the Plains and natural exposures in mountain-built belts; show that similar rocks form a large part of the continental platform. The; Shield; therefore; is a large exposure of what may be regarded as the foundation; of the continent."

Jan 1, 1954

By Belmira Benedita de Lima

Estudos no sistema Nb-B mostram a fase Nb5B6 com formação peritética a partir do líquido, porém sua estabilidade abaixo de 2.000°C não é comprovada experimentalmente. Há também dúvidas sobre a ocorrência da fase Nb2B3 neste binário. Este trabalho tem como objetivo o estudo da estabilidade das fases Nb5B6 e Nb2B3 nas temperaturas de 1.400°C e 1.800°C. Amostras com composições nas estequiometrias Nb5B6 e Nb2B3 foram produzidas através de fusão a arco assim como confeccionadas a partir de misturas de pós de B e NbB. Pastilhas com composição Nb5B6 foram produzidas com e sem adição de semente da fase Nb5B6. Os tratamentos térmicos em 1.400°C foram realizados por até 10h enquanto aqueles em 1800°C por até 1h, todos em atmosfera estática de argônio. As microestruturas das amostras, tanto no estado bruto de fusão como após tratamento térmico, foram caracterizadas por difração de raios X (XRD). Os resultados confirmam a formação fase Nb5B6 a partir do líquido e nas amostras produzidas via metalurgia do pó. A fase Nb2B3 não é observada nas amostras no estado bruto de fusão e nas amostras produzidas via metalurgia do pó tratadas termicamente a 1.800°C, porém, esta fase se estabiliza nas amostras produzidas via metalurgia do pó tratadas a 1.400°C, indicando sua estabilidade com formação peritetóide a partir das fases Nb3B4 e NbB2, abaixo de 1.800°C.

Aug 8, 2018

By Ernesto Furtado de Mello Neto, Eliezer Thuler, Claudio Vano Nunes, Carlos Alberto Cristofari

The Brazilian steel industry is dealing an adverse scenario with direct competition from global emerging markets. In this scenario, the need to improve asset operational performance, makes complex studies involving technical knowledge and asset life behavior, become important tools to support companies strategic accomplish. These studies allow consider performance, costs and operational risks relationship in the decision make process. The Asset Management approach support these studies in order to observe the whole asset life cycle, understand value chain through all company process and optimize the asset economic life. In this context, the present technical work has the purpose to support asset management decision making regarding ArcelorMittal Vega cold rolling drive motors, through the motors fail behavior modelling and estimated the risks involved in asset management decision. Through the Reliability, Availability and Mantenability (RAM) analysis, simulations were performed considering the failure, repair cost data and investments to build options to mitigate the operational risks.

Oct 9, 2019

By Donald M. Benjamin

Florida's electrical needs are served by 58 utilities of practically every type: six investor-owned, 34 municipal, 17 cooperative, and one federally-owned. They range in size from a small municipal system with a, 2 MW annual peak demand CD a large investor-owned utility serving about one-half of the state with an annual peak demand of 8,600 MW. (1),(2) These utilities are interconnected at several voltage levels with 230kV serving as the pre-dominant voltage for the bulk power transmission system. About 275 miles of 500kV circuits are found within two systems, but no tie-lines yet exist at this voltage. Due to Peninsular Florida's (that portion of the state east of the Apalachacola River) geographic location and shape, it cannot, at present, depend upon its interties with the remainder of the nation to completely support the sudden loss of the state's largest generator. Therefore, the utilities maintain a total amount of spinning reserve to cover for this single contingency outage at all times. Most of the state's electric utilities belong to the Florida Electric Power Coordinating Group (FCG) which, through its standing committees, coordinates the planning and operation of the member systems. Though a formal, centrally dispatched pool does not exist in the state, generating utilities which belong to the FCG's Operating Committee subscribe to an energy broker operation to maximize the savings that can accrue from economy interchange. Studies are underway, with participation from the staff of the Florida Public Service Commission, that are investigating both central planning and dispatch of the peninsula's electric utilities. Florida's electric load is mainly residential. During: 1976, 48.8% of all electrical energy use was by residential customers; 31.8%, commercial; 16.2%, industrial; and 3.2% for all other. By comparison, 32.7% of the United States' load was residential, followed by 40.5% industrial, 23.0% commercial, and 3.8% other.

Jan 1, 1978

By Youn-Bae Kang

Evaporation mechanism of S from liquid Fe–C–S alloys at 1873 K was proposed by analyzing available experimental data. It has been known that increasing C content in liquid alloy increases activity coefficient of S ðfSÞ, and it could raise driving force for the evaporation reaction S = S(g). However, experimental data of the evaporation of S in the Fe–C–S alloys could not be accounted for only by considering the increases of fS. In the present study, formation of carbosulfides, CS(g) and CS2(g), was additionally taken into account in order to explain role of C for the accelerated S evaporation. Surface adsorption of S was also taken into account, which retards the evaporation rate of S. An evaporation model equation was formulated. It can be applied to calculate the evaporation rate of S over wider C content (from zero to its saturation to liquid alloy).

By Thomas T., Read

THROUGHOUT the Colonial era, Philadelphia was easily , the leading city of North America, and it still held that position at the end of the period, with a population of about 25,000, though closely pressed by Boston, which had slightly over 20,000, and New York, which had nearly as many. It was the center of a region in which mineral industry was important. Thomas Rutter's bloomery, built in the Schuylkill valley in 1716, was quickly followed by many others, and during the Colonial period at least 20 blast furnaces, 45 forges, and iron- works of other types were built in eastern Pennsylvania, which easily led all the other colonies in iron manufacture. During the Revolutionary period others were erected as far west as Fort Loudon, in the Cumberland c alley.^ After 1800 the rapid development of the anthracite mining industry profoundly affected Philadelphia's, development, since transportation of the coal was then necessarily by water, and the streams of the anthracite . regions mostly flowed into either the Schuylkill or the Delaware Rivers. With an abundant near-by supply of coal and iron, with the seat of government, which had been there since 1774, and with a National Bank established there in 1791, one would have seemed safe in prophesying, at the beginning of the nineteenth century, that Philadelphia would permanently remain the leading city of the United States. Education in Philadelphia was at first wholly in the hands of the Quakers, who had established a "Public School" there in 1689, but in November 1739 George Whitefield, who had created a sensation in England by his preaching, though only 24 years old, passed through Philadelphia on his way to Georgia to found an orphan school there. He preached a series of sermons in Christ Church that were so disturbing to the established church that on Nov. 25 the Rev..Richard Peters (who was also Provincial

Jan 1, 1941

By C. Jay Hodgson, P. J. MacGeehan

"Of the 135 current or past-producing 'gold-only' mines in the Superior Province of the Canadian Shield which have produced more than 100,000 tons of ore, the 33 mines which have produced one million ounces or more of gold have accounted for over 84o/o of the total production of 137 million ounces. The published literature on these 33 deposits was reviewed in order to determine the geological setting of the mineralization on a regional (mining camp) and local (mine) scale. The dominant rock types underlying the mining camps are mafic, variolitic, tholeiitic volcanic rocks with a significant ultramafic (komatiitic) component, and clastic and/ or exhalative sedimentary rocks. Felsic volcanic rocks are generally subordinate. Most mining camps are located at or near the top of the mafic-ultramafic sequence, and generally there is a major sedimentary-volcanic contact present which may be 1) a stratigraphic superposition of volcanic and sedimentary units, 2) a rapid, along-strike gradation from dominantly volcanic to dominantly sedimentary units due to facies change, or to the formation of structurally controlled sedimentary basins during volcanism, or 3) frequently (at 40o/o of the camps) a juxtaposition of sedimentary and volcanic sequences across a major fault zone or 'break', which in many instances may represent a reactivated, syn-volcanic basin-margin fault.In contrast to the regional setting, on a local or mine scale over 90o/o of the 33 mines contain felsic intrusions and/ or extrusions within mine workings. The felsic rocks may be quartzbearing (commonly quartz-feldspar porphyries) or dominantly quartz-free (commonly feldspar porphyry syenites or monzonites), and appear to have been emplaced in two different depth-zone environments: an epizonal intrusive environment, and a volcanic vent environment. Although the distinction between epizonal intrusive and volcanic intrusive-extrusive rocks is uncertain in many deposits, the two are tentatively separated on the basis of the grain size of the rock matrix (medium to coarse grained vs aphanitic to fine grained), homogeneity (multi-phased and/ or compositionally zoned vs compositionally homogeneous), and the shape and relationship to stratigraphy of the igneous body (circular or oval in cross section, and cutting the stratigraphy at a low angle vs lenticular and either stratiform or cutting the stratigraphy at a high angle). In addition, felsic intrusions of the volcanic environment commonly grade into tuffs or breccias of extrusive origin, whereas epizonal intrusions do not.Stratiform ore zones of possible exhalative sedimentary origin appear to be confined to deposits in which volcanic felsic rocks are present, and are absent from deposits in which only epizonal felsic intrusions are present. Pervasive carbonate- rich alteration, commonly in roughly stratabound zones of regional extent, and carbonate-rich chemical sedimentary rocks are present in over three-quarters of the deposits containing quartz-bearing felsic volcanic rocks, but are much less common in deposits with quartz-free felsic volcanic rocks. The host sequences of epizonal felsic intrusions which are quartzfree are more commonly sedimentary than those of quartz-bearing epizonal felsic intrusions.Quartz, carbonate minerals, arsenopyrite, scheelite, tourmaline and Cr-muscovite ('juchsite') are the most common mineralogical associates of gold. Arsenopyrite is essentially restricted to the volcanic environment, occurring in about twothirds of the deposits with quartz-bearing felsic volcanic rocks and less than half of the deposits with quartz-free volcanic rocks. Tourmaline, on the other hand, is almost ubiquitous in deposits associated with epizonal intrusions and also occurs in about two-thirds of the deposits associated with quartz-bearing felsic volcanic rocks, but in only one of the eight deposits associated with quartz-free felsic volcanic rocks. Scheelite is essentially restricted to ores of quartz-rich fel"

Jan 1, 1982

This report provides the results of an industrial engineering study that assessed the safety and efficiency of underground ore handling in U.S. metal mines. One of the primary findings of the study was the improvement needed in controlling muck size in the ore handling stream. Oversize ore causes much additional labor, creating work stoppages and is a principal cause of accidents in metal mines. This report includes data on block caving, back cut and fill room and pillar, shrinkage stoping, and sublevel stoping.

Jan 1, 1974

By B McCarthy

Mining has been typified of late as a boom and bust, cyclical industry operating against a steady decline in the size and quality of mineral deposits. Decreasing deposit grades and increasing costs of traditional mining techniques, all in the face of another commodity downturn, are forcing mining companies more than ever before to seek out new and innovative ways to operate. New technologies are emerging to model, control and track resources through the mining value chain, to move material about mines more efficiently, and to identify and separate ore from gangue early in the extraction process.Discovering such technologies however is only the first challenge for mining companies. Actually implementing technological change successfully has proved to be an even bigger challenge. Like for many industries, fulfilling the promised benefits for the expense and timing envisioned, has not been easy when innovative technologies are introduced.Citing the author’s insights and experiences in a number of emerging technologies, this paper explores barriers to implementing technological change in the mining context. Key elements of a change management framework, first developed for implementing mine management systems, are described to give mining executives insight into how they and their organisations can succeed through technology-driven change.CITATION:McCarthy, B, 2016. Successfully implementing technology-driven change in the mining environment, in Proceedings International Mine Management Conference, pp 89-104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

A computer simulation of the automatic control of continuous mining machines has been prepared, similar to previous simulations of longwall mining systems and coal thickness sensors. The simulation allows for programmed variation of the horizon detection method, the azimuthal guidance system, the type and configuration of the miner, varying hardness in the unmined face material (leading to varying error in the machine heading), and the miner's cutting cycle. It simulates control of the miner in three axes. Use of the simulator makes it possible to anticipate problems arising from the complex character of underground mining, which include unpredictable multi-pass coupling and unpredictable variation in geological conditions.

Jan 1, 1993

By E. G. Ozhogina, O. B. Kotova

"The ores of black, non-ferrous, rare, noble metals are mostly distinguished by a variety of mineral types and complexity of their material composition. This article is devoted to the promotion of the concept of mineral processing in modern realities of the deficit of high–grade ores and increase in their demand. Normative and methodical documentation for specific types analysis with the definition of the field of application are presented in this paper. . For example, the pyrochlore-monazite-goethite ores from one of the deposits from Eastern Siberia - Chuktukonskoe ore field were tested. The development of mineralogical methods and testing of specific raw materials are shown. The method of small-angle X-ray (and also synchrotron) scattering, which was developed for solving problems associated with structural high-resolution diagnostics, was tested for bauxites of Vezhay-Vorykvinskoye field.INTRODUCTION A highly intense production of many types of mineral deposits results in gradual depletion and of mining-geological and mining-technical conditions of various ore reserves ?. Relatively easily accessible and rich deposits are getting depleted in the first place, and it is necessary to involve low grade and refractory ores into production and processing. Traditional technologies can hardly be applied (Chanturia, 2017; Bazin et al., 2014; Ponaryadov, 2017). The urgency of development of the concept of technological mineralogy focuses on the confirmation of new methods and approaches to the development of mineral deposits, creation of scientific and methodological pre-requisites for solving the problem of rational development of mineral deposits, maximum extraction and integrated application of all minerals (both principal and associated), expansion and strengthening of mineral and ores.The article is aimed at updating tasks that should be addressed within the applied mineralogical research: – forecast of quality of ore at early stages of exploration and technological indicators for the redistribution of properties ore, – interactive monitoring of these indicators by mineralogical and analytical methods;"

Jan 1, 2018

By D. W. Duncan, A. Bruynesteyn

Acidic mine waters containing solubilized uranium have been observed in many uranium and some copper mines. In every case, the sulphide and iron oxidizing bacterium, Thiobacillus ferrooxidans, was also present. This bacterium provides the ferric iron required to oxidize u+4, both by oxidizing available ferrous iron and by oxidizing pyrite or other available sulphide minerals. This latter oxidation also provides sulphuric acid and may increase extraction by exposing more uranium. The enhancement of bacterial activity and the results of some field tests are discussed.

Jan 1, 1971

By E. G. Ozhogina, O. B. Kotova

"The ores of black, non-ferrous, rare, noble metals are mostly distinguished by a variety of mineral types and complexity of their material composition.The article is devoted to the promotion of the concept of mineral processing in modern realitiesof the deficit of high-quality ores and increase their demand.Normative and methodical documentationsfor specific types of analysis with the definition of the field of application are shown. For example,the pyrochlore-monazite-goethite ores from one of the deposits from Eastern Siberia - Chuktukonskoe ore fieldare tested. The development of mineralogical methods, and testing of specific raw materials are shown.The method of small-angle X-ray (and also synchrotron) scattering, which was developed for solving problems associated with structural high-resolution diagnostics, was tested for bauxites of Vezhay-Vorykvinskoye field. KEYWORDS Technological mineralogy, rebellious ores, ore quality assessment, ?mineralogical-analytical methods INTRODUCTION A highly intense production of many types of mineral raw results in gradual depletion and deterioration of mining-geological and mining-technical conditions of development. Relatively easily accessible and rich deposits are getting exhausted in the first place, and it is necessary to involve poor and rebellious ores into production and processing. Traditional technologies can hardly be applied (Chanturia, 2017; Bazin et al., 2014; Ponaryadov, 2017). The urgency of development of the concept of technological mineralogy focuses on the confirmation of new methods and approaches to the development of mineral raw, creation of scientific and methodological prerequisites for solving the problem of rational development of mineral raw, maximal extraction and integrated application of all minerals (both principal and associated), expansion and strengthening of mineral and raw base. The article is aimed at updating tasks that should be addressed within the applied mineralogical researches: – the forecast of quality of ore at early stages of exploration and technological indicators for the redistribution of raw, – interactive monitoring of these indicators by mineralogical and analytical methods; – assessment of environmental consequences of mining and processing of minerals and measures that eliminate these consequences."

Jan 1, 2018

By J. Greenspan

The anisotropy of fracture and slip, that is, the brittleness and ductility of the beryllium single crystal, is characteristic also of po1ycrystalline beryllium in which the grains are oriented in a preferred manner. Beryllium with grain orientations resulting from hot working either unidirectionally or bidirectionally is ductile or brittle in directions given by the anisotropy and orientation of the grains. Textures developed from various hot-working sequences are given, and tensile results are correlated with textures. Not only texture, but fine grain size is necessary for obtaining high tensile elongation. Ultimate tensile strength and elongation are both correlated with grain diameter. Of particular interest is the case in which unusually high tensile elongations of 30 to 40 pct are obtained when basal planes are oriented to carry THE beryllium crystal (of nominal purity) is probably unique among metals with respect to its unusually acute anisotropy of slip and fracture. While extensive slip can occur on the system (1010) [ll20] starting at about 19,000 psi, the (0001) plane is particularly vulnerable to fracture at 4500 psi or less. Fracture occurs also on the (11zo) plane at about 26,000 psi.1"3 Further, there seems to be no other slip System which contributes significantly to

Jan 1, 1960

By Frances H. Clark

IN a concern with the varied interests of the Western Union Telegraph Co., where practically all types of metals, both ferrous and nonferrous, are utilized, many types of failures of materials occur. These have to do not only with outside plant construction, such as corrosion and fatigue of line wire and cable, but also with inside plant equipment operating at such high speeds that rapid deterioration of metal. parts due to fatigue and wear results. Both corrosion and fatigue affect the life of copper wire so its normal life in any particular locality is largely dependent on the atmospheric conditions. Tensions vary widely owing to changes in temperature and ice and wind loadings and the wire is Subject to a great range of vibration caused by wind gusts aril vibration front trains or other heavy vehicles transmitted through the earth. High frequency low-amplitude vibrations are sometimes audible as singing in the wire. The other extreme is the vertical slashing or dancing of the wire observed during severe storms where amplitudes of 9, ft. or more at low frequencies have been observed.

Jan 1, 1942

These tentative inspection standards have been prepared as a guide for the Federal inspection of the anthracite mines of the United States. The Federal Coal Mine Inspection Division is not a mining-law-enforcement

Jan 1, 1943

By K. R. Van Doren

The polynomial method for estimating virial coefficients from experimental data suffers from three serious defects: (1) There is no known relationship between the polynomial coefficients and the virial coefficients, (2) the values of the estimates depend upon the degree of the polynomial and the particular set of values used for the independent variable, as well as the random errors in the dependent variable, and (3) the variances calculated for the estimates do not represent the mean square errors of estimation. Attempts to overcome these defects have thus far been unsuccessful; these attempts have also failed to account for the fact that none of the virial coefficients are uniquely determined by the values of the dependent variable for a finite set of values of the independent variable. The conclusion is that virial coefficients cannot be reliably estimated from experimental data unless additional information about the virial expansion itself, such as its rate of convergence, is available.

Jan 1, 1969

By Matthew Geary, Stephen J. Marino, Jordan A. Schreiner

"INTRODUCTION Project Overview The Southeast Collector (SeC) is a new 15km long 3.0m internal diameter wastewater tunnel designed by Hatch Mott MacDonald (HMM) that twins the existing 2.6m diameter York-Durham Sewage System (YDSS) tunnel. Both sewage tunnels are located north of the City of Toronto in Ontario, Canada. The SeC provides much needed conveyance capacity for the rapidly growing York Region population, supporting development until 2036 and increasing sewage system security (Hatch Mott MacDonald and AECOM 2011). Construction of the SeC will also permit flows of the twinned section of the YDSS to be bypassed in order to clean, inspect and carry out any essential maintenance within the YDSS tunnel. Although owned and operated by York Region, the SeC spans two regional municipalities beginning upstream from the intersection of Ninth Line and Rouge Bank Drive in the City of Markham in York Region to the downstream Finch Avenue and Valley Farm Road intersection in the City of Pickering in Durham Region. See Figure 1 for the SeC and YDSS alignment. The project includes 19 shafts and chambers with depths ranging from 8 to 48m in addition to seven facilities supporting the operation and maintenance of the sewer. The construction contract was awarded to Strabag Inc. in July 2011 for $291M CAD. Construction Management services were provided by a joint venture team of Hatch Mott MacDonald and AECOM. Existing York-Durham Sewage System The YDSS tunnel was completed in 1979 and was constructed using an open shielded TBM with ribs and lagging temporary support, followed by installation of a 380mm thick unreinforced cast-in-place (CIP) concrete final lining. The YDSS sewer system has numerous connections that accumulate flows from various urban areas within York Region. The section of the YDSS twinned by the SeC flows under gravity conditions and had been putting a strain on the municipality’s potential for population and development growth having reached its maximum capacity of 420 ML/d. According to the York Region’s Water and Wastewater Master Plan, the existing YDSS would not have been able to handle wet weather flows past 2016 (Genivar and XCG Consultants 2009). The dependability of this section of the YDSS is also of concern because it is the main and critical connection between the sewer systems upstream and the downstream Duffin Creek Water Pollution Control Plant (WPCP)."

Jan 1, 2016

By W. Vickers

SALKOVITZ1 has given a number of useful angles between planes for use with the Laue method in determining the orientation of bismuth single crystals. Bismuth is usually considered as having a face-centered-rhombohedra1 structure with its axial angle 87°34', Fig. 1. A similar figure given by Sal-kovitz appears to be in error in that the angle there marked as 87°34' should be 92°26. The primitive cell is a single rhombohedron of axial angle 570 14. The structure is almost face-centered-cubic and hence high accuracy in measurements is essential if there is to be no confusion in indexing poles or zone axes. It is easier to get this accuracy if zone axes are plotted on the stereogram because they will lie near the basic circle where the net has a more open scale. The zone axes can be read from the film, using a Greninger chart, and can be plotted more accurately than poles. Also, the angles between points near the basic circle can be read more accurately than those between poles near the center. In order to use the zone axes the angles between directions have been calculated from a formula given by Niggli,2 and are given in Table I. Miller indices

Jan 1, 1958

Kroemer(1-3) and Kroemer et al.(4) define the isoinertial technique of strength assessment as one in which mass properties of an object are held constant, as in lifting a given weight over a predetermined distance. Several strength assessment procedures possess this characteristic. Most commonly associated with the term is a specific test developed to provide a relatively quick assessment of a subject's maximal lifting capacity using a modified weight-lifting device.(1,5) The classic psychophysical methodology of assessing maximum acceptable weights of lift is also considered an isoinertial technique under this definition.(6) While the definition provided by Kroemer(1) and Kroemer et al.(4) has been most widely accepted in the literature, some have applied the term "isoinertial" to techniques that differ somewhat from the preceding definition, such as in a description of the Isotechnologies B-200 strength testing device.(7) Rather than lifting a constant mass the B-200 applies a constant force against which the subject performs an exertion. The isoinertial tests described here apply to situations in which the mass to be moved by a musculoskeletal effort is set to a constant. Is Isoinertial Testing Psychophysical or Is Psychophysical Testing Isoinertial? As various types of strength tests have evolved over the past few decades, some unfortunate developments in terminology have arisen to describe and classify different strength assessment procedures. This is particularly evident in sorting out various tests that have been labeled "isoinertial." One example was cited earlier. Another problem that has evolved is that the term "isoinertial strength" has two connotations. The first is the conceptual definition: isoinertial strength tests include any strength test in which a constant mass is handled. In practice, however, the term is often used to denote a specific strength test in which subjects' maximal lifting capacity is determined using a machine and a constant mass is lifted.(1,5) Partially as a result of this dual connotation, the literature contains references to both "isoinertial strength test" as a psychophysical variant(8) and the psychophysical method as an "isoinertial strength test" (4,9) To lay the framework for the next two chapters, the authors will briefly discuss some operational definitions of tests of isoinertial and psychophysical strength. In stating that the isoinertial strength test is a variant of the psychophysical method, Ayoub and Mital(8) refer to the specific strength test developed by Kroemer(1) and McDaniel et al.(5) Clearly, this isoinertial protocol has many similarities to the psychophysical method: both are dynamic; weight is adjusted in both; and both measure the load a subject is willing to endure under specified circumstances. However, while both deal with lifting and adjusting loads, there are significant differences between the psychophysical (isoinertial) technique and the Kroemer-McDaniel (isoinertial) protocol in their procedures and the use of the data collected in these tests. For our purposes, we designate the

Jan 1, 1998