Search Documents

By W. M. Pierce

CORRUGATED sheet zinc has been used abroad for a great many years as a roofing material. In this country it has been in use for about 10 years. From the outset it was recognized that zinc sheets required closer spacing of the supporting purlins than steel sheets. Exact data regarding safe maximum fiber stresses were not available, however, and on occasions the span used was excessive and the sheets sagged. This paper describes both service and laboratory tests to determine safe maximum fiber-stress values for various grades of zinc for use in calculating the proper purlin spacings for any gage and profile under given loading conditions. These tests consist of laboratory loading tests on full-size roof sections over extended periods of time; of actual roof installations erected in conformity with the indications of the laboratory tests and observed over a period of years; of careful determinations of the apparent elastic limit of several grades of zinc, and finally of static tests1 (so-called creep tests) to determine the rate of flow of zinc under a variety of static tensile stresses at definite temperatures. Certain of the individual tests extended over a period of more than two years.

Jan 1, 1929

By W. M. Ma, Daniel W. H. Su, K. Centofanti, Yi Luo, W. L. Zhong, Syd S. Peng

1.1 INTRODUCTION When underground mining involves total extraction, it induces overburden strata movements. If not properly planned it causes surface subsidence and affects surface environmental conditions. Total extraction usually refers to longwall mining and room and pillar mining with pillar extraction. Surface subsidence has long been a subject of intensive research for scientists all over the world and considerable achievements have been obtained. However due to its difficulties and complicated nature, research into overburden movement has been thus far incomplete as compared to that into surface subsidence. Since surface subsidence is a manifestation of the results of overburden movement, the processes and mechanisms of overburden movement must be fully understood in order to establish the mathematical prediction models of surface subsidence. In this chapter the processes of overburden movement and its zones of movement in the overburden will be discussed. 1.2 PROCESSES OF OVERBURDEN MOVEMENT When total extraction is used, it produces a large void in the coal seam and disturbs the equilibrium conditions of the surrounding rock strata. The roof strata bend downward while the floor heaves. When the excavated area (or gob) expands to a sufficient size, the roof strata will cave. As a result, the overlying strata continue to bend and break until the piles of the fallen rock fragments are sufficiently high to support the overhanging strata. At this tie the overhanging strata no longer cave, but bend and rest on the underlying strata. Strata bending and subsidence develop upward until reaching the surface and forming a subsidence basin. The whole overburden strata and the surface subsidence basin will further go through a period of compaction and gradually become stabilized. Current knowledge regarding the process of overburden movement has been derived from several sources. One is the direct observation of the mined sections and their surfaces, another from field monitoring of strata movements in the overburden, and others from computer modeling and scale modeling in the laboratory. For example, Figs. 1.1 and 1.2 show the results of a borehole monitoring experiment (Borehole B-2) using the full profile borehole inclinometer and full profile borehole extensometer for lateral displacements and vertical subsidence, respectively (Conroy and Gyarmaty, 1983). The panel, 400 ft wide by 5000 ft long and 630 ft deep, was extracted from the Pittsburgh No. 8 seam which had an average thickness of 54 in. The face advanced from east to west. Curve A in Fig. 1.1 shows the inclination of the borehole when it was 45 ft ahead of the face at Position A (i.e., on the solid coal side). The total deviation of the borehole was 1/7000. The first shear movement occurred at 130 ft above the coal seam and appeared to have occurred along the bedding plane with large contrast of rock strata on both sides, i.e., sandstone vs. shale. When the face had passed the borehole 79 ft at Position B, the borehole deformed to assume a bow shape with a maximum deviation of 2.8 in. from the center line. Numerous shearing planes occurred and extended further upward. When the face had passed the borehole by 75 ft at position C, strata subsidence was measured. Fig. 1.2 shows that a strata separation as large as 4 ft occurred at 40 to 100 ft above the coal seam. Above this level, the strata subsided more uniformly with bedding separations within 1 to 2 in. Another example is the longwall mining with complete caving in the Soviet Union's Karaganda Coalfield (Kolebaeva, 1968). The coal seam was 6 ft thick and 154 ft deep. The immediate roof was the fine-grained sandstone interbedded with coarse-grained sandstone. Above this, there was sandy shale and shale. In order to monitor the process of overburden movement, 15 stations were established in a borehole (Fig. 1.3). The elevations of those stations were measured when the face was at various distances from the borehole. Fig. 1.3 shows the movement history of each station. For convenience of comparison, the movement history of each station was plotted on a common reference point as shown in Fig. 1.4. Clearly, the movements of strata from Station # 1 to #6 were nearly simultaneous, i.e., they behaved as a single unit. The strata from Station #7 to # 15 had differential separations, the maximum of which was 40 in. As the face passed by and moved away, strata separations in general reduced gradually. But strata separation between Stations #12 and #13 remained the same until the end of the monitoring period. The total bed separation between Station #7 and # 15 reached 11 in., approximately 18% of seam thickness, when the face was 132 ft beyond. Based on the above observations, the author developed a conceptual model of overburden movement due to underground longwall mining (Fig. 1.5). The above-mentioned two case studies illustrated that subsidence in the overburden strata propagates upward and subsidence velocity decreases from the bottom to the top. When the subsidence velocity at the surface reaches the maximum value, the subsidence velocity at the bottom portion of the overburden strata has decreased considerably and the strata have begun to compact. Bed separation occurs within a certain distance above the coal seam and reduces from the bottom to the top. When the face has moved away, bed separation reduces gradually, so that eventually some beds completely close and others partially close. Bed separation reaches the highest level when the subsidence velocity at the surface is at its maximum value. For instance in Fig. 1.4 surface subsidence velocity was maximum when the face was 38 to 44 ft past the point. At this time the total bed separation was maximum. Overall the strata directly above the opening are subjected to tension in the vertical direction. But above a certain level, all strata move nearly simultaneously. There is also significant shear movement along some bedding planes. 1.3 ZONES OF MOVEMENT INTHEOVERBURDEN After the extraction of a longwall panel or room and pillar section of sufficient width the strata in the overburden are subjected to various degrees of movement from the bottom to the top. According to the movement characteristics, the damaged overburden can be divided into four zones (Fig. 1.6). Caved Zone. After the extraction of coal, the immediate roof caves irregularly and fills up the void. The strata in this zone not only lose their continuity completely, they also lose their stratified

Jan 1, 1992

By Myron A. Pugacz, Frank S. McKenna, Clarence E. Jackson

The notched-bar impact test has proved worth while in certain applications as a test for control of the quality or the heat-treatment of steel. In view of the serious thought that even so simple a test as the tensile test has evoked during the past years, it is not surprising that the notched-bar impact test should have inspired much experimental work. The correlation of the great number of data has not been successful, although steady progress has been made toward a better understanding of this test. Progress has been made, especially, in the isolation of the effects of the many variables that control the results. The stress system imposed on a specimen with a notch is so complicated and unpredictable that no simple evaluation of the test has been possible. Because of this uncertainty, many engineers hesitate to use the notched-bar impact test, and this attitude may well continue until a better understanding of the effects of the variables in the test are available. Without doubt, any additional data that may be presented should be accompanied by as complete a description of the - details of test as possible, so that it may be added to the general fund of information that is to serve as the basis for the theory of the notched-bar impact test. The many factors that may control the test results have been pointed out repeatedly. The importance of the effect of the type and dimensions of the specimen has been recognized. Most of the work reported by American investigators has been limited to small-size (Charpy) specimens tested as a simple beam; two types of notches (Fig. I) have been commonly used. Considerable data have also been presented by many investigators using a small specimen tested as a cantilever beam; this commonly being called the Izod test. Here, however, a shear component of stress makes the stress system even more complex than that present in the simple beam type of test, hence a critical analysis is difficult. Much work has also been reported by investigators using the tension type of specimen. A second variable that must be controlled is the testing temperature. An indication that the tests were performed at room temperature is not sufficient, since in many steels a variation of a few degrees in the actual testing temperature may be sufficient to give an entirely different range of results. Other factors, such as the composition and condition of the material being tested and the speed of test, should also be considered. Many investigators have contributed data and theoretical discussions on the problems encountered in notched-bar test-

Jan 1, 1944

By Frank S. McKenna, Myron A. Pugacz, Clarence E. Jackson

The notched-bar impact test has proved worth while in certain applications as a test for control of the quality or the heat-treatment of steel. In view of the serious thought that even so simple a test as the tensile test has evoked during the past years, it is not surprising that the notched-bar impact test should have inspired much experimental work. The correlation of the great number of data has not been successful, although steady progress has been made toward a better understanding of this test. Progress has been made, especially, in the isolation of the effects of the many variables that control the results. The stress system imposed on a specimen with a notch is so complicated and unpredictable that no simple evaluation of the test has been possible. Because of this uncertainty, many engineers hesitate to use the notched-bar impact test, and this attitude may well continue until a better understanding of the effects of the variables in the test are available. Without doubt, any additional data that may be presented should be accompanied by as complete a description of the - details of test as possible, so that it may be added to the general fund of information that is to serve as the basis for the theory of the notched-bar impact test. The many factors that may control the test results have been pointed out repeatedly. The importance of the effect of the type and dimensions of the specimen has been recognized. Most of the work reported by American investigators has been limited to small-size (Charpy) specimens tested as a simple beam; two types of notches (Fig. I) have been commonly used. Considerable data have also been presented by many investigators using a small specimen tested as a cantilever beam; this commonly being called the Izod test. Here, however, a shear component of stress makes the stress system even more complex than that present in the simple beam type of test, hence a critical analysis is difficult. Much work has also been reported by investigators using the tension type of specimen. A second variable that must be controlled is the testing temperature. An indication that the tests were performed at room temperature is not sufficient, since in many steels a variation of a few degrees in the actual testing temperature may be sufficient to give an entirely different range of results. Other factors, such as the composition and condition of the material being tested and the speed of test, should also be considered. Many investigators have contributed data and theoretical discussions on the problems encountered in notched-bar test-

Jan 1, 1944

By Eric J. Foell

Recognizing that the planned commercial exploitation of polymetallic nodules in the deep sea should be accompanied by environmental studies in order to protect this largest and least understood ecosystem of our planet, the German Ministry for Research and Technology has since 1989 funded a longterm and large-scale disturbance-recolonization (DISCOL) experiment in the abyssal Peru Basin of the equatorial South Pacific Ocean. The circular study site is located at 4150m depths and encompasses about 10km2 of relatively flat, heavily sedimented sea floor with low (< 15%) nodule coverage near an existing German nodule mining exploration license area. The RV SONNE, a large and well-equipped multi-purpose research vessel, served as platform for all environmental cruises conducted to date. The initial DISCOL expedition (SO-61, Feb.-March 1989) was carried out in two legs. During DISCOL 1/1, a study site was selected, a pre-disturbance baseline assessment was undertaken, and sea floor disruption was begun using the "plow-harrow", a uniquely designed disturber device towed repeatedly across the circular study area. During DISCOL 1/2, disturber deployments continued until the device had created 78 criss-crossing and partially overlapping tracks along which nodules were essentially plowed under while sediment from up to 15cm below the seabed had been turned over and exposed at the surface. In addition to the obvious within disturber track impacts, sediment mobilized by plowing drifted off with the prevailing near-bottom current and redeposited downstream, blanketing nearby areas not directly disturbed. Immediately after the disturbance phase, an initial post-impact sampling series was performed. The DISCOL Experimental Area (DEA) was revisited about six months (DISCOL 2, SO-64, Sept. 1989), three years (DISCOL 3, SO-77, Feb. 1992), and seven years (ATESEPP SO-106, Jan.-March 1996) after disturbance to collect further post-impact samples, monitor changes in the benthic community and follow the recolonization process. In addition to benthic community studies, plankton investigations were initiated during the third DISCOL cruise (SO-77) and continued during three further cruises (SO-78, SO-79 and SO-80/2) in 1992.

Jan 1, 1996

By W. A. Selvig

"INTRODUCTION In 1942, Lowry and Junge 3/ reported the results of a statistical study of errors for the proximate and ultimate analysis of coal and coke when made according to the standard Methods of Laboratory Sampling and Analysis of Coal and Coke (D271-42) 4/ of the American Society for Testing Materials. Some of the laboratories that cooperated in the investigation reported difficulty with determination of the volatile matter of anthracite and low-temperature coke. The small number of analyses reported for these particular fuels was considered inadequate to justify definite conclusions regarding the precision of this determination.The investigation described in this report was made at the request of Committee D-5 on Coal and Coke, A.S.T.M. (A. C. Fieldner, chairman), to secure additional information regarding the errors of the volatile matter determination for anthracite, low-temperature coke, and subbituminous coal; the last fuel also gives trouble in this determination, The committee has recognized that the allowable differences between duplicate determinations of volatile matter for these fuels as given in the standard methods are perhaps too stringent and may require revision."

Dec 1, 1943

By P. Tumialán

El presente trabajo señala la modalidad del empleo en la exploración de las estructuras mineralizadas en diversos yacimientos métalicos a través del estudio de las curvas de sus leyes, curvas estructurales, de potencia y las de cocientes metálicos. Es decir, en este tipo de estructuras se puede estudiar un tipo de las curvas señaladas anteriormente. Asimismo, la mejora del análisis de este tipo de curvas depende de la relación con la petrografía de las cajas, tipos de alteración hipógena, supérgene, rumbo y buceamiento de las mismas, minerales opacos, y ganga de la estructura mineralizada, fracturas y fallas de premineralización y de posmineralización.

Nov 20, 1972

By G. S. Phipps, E. E. Schumacher, G. M. Bouton

THE seriousness of the present tin scarcity has stimulated large consumers of this vital metal to develop drastic conservation measures in order to extend the available supplies to cover the emergency period. By devising new soldering methods and alloys the Bell System has contributed a substantial share in the tin conservation effort, Fortunately, the changes, as far as can be determined now, have not introduced weakness into the soldered joints. Some of the new procedures were already in the process of development at the onset of the emergency, while others were devised under its stress. In some instances, the newly developed solders were found to be more difficult to use than the alloys previously available, and would not have been introduced under normal conditions. One major change made that previously had been under consideration will result in large savings of tin. Unless service difficulties are encountered, this modification gives promise of remaining after the emergency has passed. The change involves a reduction in the amount of solder placed on a wiped joint between the cable sheath and the sleeve. Instead of the customary full sized wiped joint, a wipe of fillet proportions is formed. Through this change, a solder saving of more than 60 per cent per joint can be realized. Plumbers and cable splicers for many years have joined lead pipes and cable sheath by a soldering process called "wiping." The name is an apt description of the operation. For a wiped joint, the sections to be united&apos; are heated by molten solder poured over their surfaces, and the resulting semiliquid mass is manipulated by wiping with cloth pads to a well rounded symmetrical form like the one shown in Fig. I, The operation requires considerable skill on the part of the splicer and close control of the composition of the solder. At first consideration, the problem of tightness in such joints seems simple but experience shows that even under the best conditions the fissures frequently found in the solder occasionally link and form a path that allows leakage to occur. In telephone cables not maintained under gas pressure, such leaks permit the entrance of water, which wets the paper-covered conductors and thereby impairs the insulation value and causes service interruptions. By going to an extreme and wiping off all the solder in excess. of a fillet, it has been found that many causes of porosity are eliminated. Figs. 2 and 3 show cross sections of joints wiped in the old and the new ways. The saving in solder, and consequently in strategic tin, is evident. The field splicing forces find that joints are easier to make by the new method and are less likely to be porous. The metallurgical considerations that are responsible for the success of the fillet wipe are of interest. Much has been written about the wiping process of soldering cable joints and the many requirements of a good wiping solder have frequently been listed. The success of the procedure described

Jan 1, 1943

By John F. Blandy

Although the question of the "waste of anthracite coal mining " has been so frequently discussed, and a committee was appointed at the first meeting of this Society to consider and report upon the subject, still but little progress seems to have been made in arriving at a conclusion as to how it ran be reduced. That committee made a preliminary report at the August meeting, 1871, in which it divided the question into three parts, namely: Waste in mining, in preparing for market, and in transportation. I shall not here refer to the first item, as so much depends upon the peculiar features of each separate mine, and the skill of those in charge; but in reference to the second, that of preparing the coal for market in breaker and screens, I wish to make some remarks. There is no use considering the question, whether the coal should be broken up to suit the fancy of consumers; all miners are satisfied that it should not be, but the consumers decide that they want it that way, and the miner must submit, and simply utter his maledictions upon the head of the man who first suggested a breaker or screen, if that is any consolation to him. What is called waste in this process of preparation, is the dust and fine coal, which results from the breaking and screening, and, as we all know, this is a very important percentage of what passes from the slope to the top of the breaker. Now, if this dust and fine coal can be utilized—the slate which is picked out is not to be taken into consideration as waste—then we get rid of this item entirely. There is no question in my mind that this article can and will be used as a steam generator at least, and I think, therefore, that in depositing

By John F. Blandy

ALTHOUGH the question of the "waste of anthracite coal mining" has been so frequently discussed, and a committee was appointed at the first meeting of this Society to consider and report upon the subject, still but little progress seems to have been made in arriving at a conclusion as to how it can be reduced. That committee made a preliminary report at the August meeting, 1871, in which it divided the question into three parts, namely Waste in mining, in preparing for market, and in transportation. I shall not here refer to the first item, as so much depends upon the peculiar features of each separate mine, and the skill of those in charge; but in reference to the second, that of preparing the coal for market in breaker and screens, I wish to make some remarks. There is no use considering the question, whether the coal should be broken up to suit the fancy of consumers; all miners are satisfied that it should not be, but the consumers decide that they want it that way, and the miner must submit, and simply utter his maledictions upon the head of the man who first suggested a breaker or screen, if that is any consolation to him. What is called waste in this process of preparation, is the dust and fine coal, which results from the breaking and screening, and, as we all know, this is a very important percentage of what passes from the slope to the top of the breaker. Now, if this dust and fine coal can be utilized-the slate which is&apos; picked out is not to be taken into consideration as waste-then we get rid of this item entirely. There is no question in my mind that this article can and will be used as a steam generator at least, and I think, therefore, that in depositing

Jan 1, 1877

By Swati Mohanty, G. V. Rao

Sedimentary dolomitic phosphate ores are difficult to treat by flotation, and high-grade phosphate concentrates with high recoveries are difficult to obtain. The literature indicates that the reagents required for beneficiation of such ores are generally dictated by the nature of the gangue. In this paper, the optimum flotation parameters necessary for enhancing the grade and recovery of a typical low-grade dolomitic rock phosphate ore from Jhamarkotra, Rajasthan, are highlighted. The standard design-of-experiment (DOE) technique was used to obtain empirical models for both grade and recovery. The model equations were then used for optimizing the flotation parameters, including pH, percent solids, collector dosage and depressant dosage. Laboratory experiments demonstrated that a phosphate concentrate containing about 36% P205, with a recovery greater than 95%, can be obtained in a single-stage by the reverse flotation of carbonaceous minerals at the optimized conditions. Key words: Phosphate, Flotation, Dolomite

Jan 1, 2003

By Godresse M, Turczynski G. P J, Driver I. J, Low G, Ozawa N

Geological evaluations of coal deposits have been traditionally undertaken in a somewhat manual manner. Information is collected downhole by chip sampling, coring and using downhole geophysical logging. This information is then interpreted by an experienced geologist to define the coal and noncoal lithological units. Coal units were subsequently correlated to provide data for structural modelling. In recent years a number of advancements in interpretation techniques have been made based on Artificial Intelligence. This paper describes an integrated geological interpretation system based on maximised use of Al techniques. The first part describes the lithological interpretation which uses a number of boreholes with both logged lithology and downhole geophysical logs. This information provides a learning set of data to the neural network. The second part concentrates on the correlation of both coal and noncoal units from borehole to borehole. Problems in this area, in a manual sense, are interpretation of correlation across weathering zones and other geological anomolies. The technique is based on pattern recognition and dynamic programming techniques where a correlation matrix is developed relating all holes with their maximum correlations.

Jan 1, 1995

By M. G. Ayat, J. W. Leonard

Introduction Coal preparation plants are continuously losing clean coal in their refuse and contaminating their clean coal product with impurities. This is due to the lack of a system by which the immediate efficiency of the cleaning operation can be determined at any given time. Moreover, the advantage of developing tagging/ tracing techniques would be a reduction in the time and money spent in evaluating the performance of advanced cleaning techniques. Currently, conventional sampling and testing, on-line analyses, and computer information systems are the major tools with which engineers analyze and control the efficiency of processing plants. Conventional sampling and testing is an effective analysis technique but it is slow. On-line analysis provides information on quality parameters rapidly, but these parameters do not provide all of the necessary information. The use of tagged particles in coal preparation plants may provide the necessary link between diagnosis and the application of computers to process control. In this work, a novel technique that uses tagged particles to generate partition data is presented (Leonard et al., 1982). Individually prepared tagged particles are added to the feed and detected in the product or refuse port of specific gravity based processes. Providing that a computer can interpret the output of a detection device and trace particles with predetermined physical properties through the coal preparation plant and that the trace particles actually represent desired raw material, sufficient partition data can be provided for computer analyses and control of processing efficiency. Coal tagging technique The use of tagged particles in coal preparation operations are in the early stages of development. Though there is a brief history of particle tracing in the mineral processing industry (Gardner et al., 1986; Foreman and Amundson, 1976; Poston et al., 1962), the concept has not yet been applied to the analysis and control of processing plant operations. Several methods for tagging coal particles have been identified. These include magnetic, radioactive, and fluorescent techniques. As far as the magnetic tagging of coal particles is concerned, a method has been developed to manufacture synthetic magnetic particles of various sizes and specific gravities. Ideally the synthetic particles would have identical size and density as the coal particles being separated.

Jan 1, 1988

By W. Morgan NeSmith

Drilled displacement (DD) piles often develop significantly larger unit shaft resistance values than other drilled or augered pile systems in coarse grained materials. Minimal vibration and limited spoil development are also associated with DD pile installation and these factors are frequently additional financial and/or environmental benefits of the system. The application of DD piles in North America dates to the mid-1990s and their use in the Midwestern United States has been significant, particularly in the past 10 years. The authors have collected an extensive database of DD pile performance in the United States. The alluvial and glacial deposits of the Midwestern U.S. provide conditions where drilled displacement piles perform very efficiently when compared to coastal and residual geologies. This paper presents a summary of the authors? experience regarding installation and performance of DD piles in the Midwestern U.S. Information presented includes summary presentations of DD performance across a range of site conditions as well as a discussion of the relationship of DD performance and installation effort in the Midwest as compared to other geologic settings in the U.S.

Jan 1, 2009

By Michael Tenenbaum

Selected characteristics of nonmetallic phases were determined in low-carbon sheet steels which had been produced by various refining; deoxidizing, and casting procedures. The results showed little influence of the refining process on the quantity, distribution, size, and character of the nonmetallic phases. The quantity of inclusions was governed by the deoxidation procedures. While the mode of casting influenced the internal structure and the pattern of inclusion distribution, it had little effect on the quantity of nonmetallics. The vast majority of inclusions were under 30 µ in diam, and there was little change in size distribution during hot and cold rolling. The composition and structure of the inclusions were expained an the basis of known equilibrium phase diagrams for the appropriate systems. Additional work is needed to explain some of the observations of this paper. HENRY Marion Howe&apos;s contributions to the metallurgical profession include his many writings, the wisdom that he imparted to his students, and the inspiration that he gave to the many scholars, teachers, and industrialists who knew him personally. It was Professor Howe&apos;s intimate colleague, Albert Sauveur,1 who, in the first Howe Memorial Lecture, could have been speaking for the metallurgist of our generation as well as his own when he wrote, "...how many of us on the point of going astray were called back to the right path by Howe&apos;s guiding torch?" More than a quarter of a century later, Francis Foley,2 one of the last in the Howe Lecture series who worked directly with the great man, delivered the ultimate tribute, "...truth, in its time is so hard to identify." While Professor Howe strove to be right, "he was content if he provoked the reader to take the next step along the path to greater knowledge." Like so many of my predecessors, I sought guidance for this lecture by referring to Professor Howe&apos;s two classic texts, Metallurgy of steel,3 and Metallography of Steel and Cast Iron: the former book interpreting the facts as he saw them near the start of his career, and the latter—published 26 years later—pointing to many fertile fields for metallurgical investigation. Those of us who harvest the fruits of Henry Marion Howe&apos;s contributions to the metallurgical profession now look with wonder at the tremendous legacy he has provided. It is rewarding to study his writings and to recognize the anticipation of such aspects of modern ferrous metallurgy as: 1) Direct reduction 2) Steelmaking reactions 3) The approaches and benefits of degassing 4) Solidification mechanisms 5) Habits and behavior of nonmetallic inclusions 6) Recrystallization phenomena 7) Slip and slip propagation 8) Dislocations 9) Discontinuous deformation 10) Microscopic and macroscopic segregation

Jan 1, 1970

By C. A. Wilson

The Bureau of Mines started a continuing program to investigate and evaluate analytical techniques to assist governmental agencies to select simple, rapid, reliable methods for crude oil spill identification. Six crude oil samples were analyzed to evaluate gas-liquid chromatography, atomic absorption spectrophotometry, infrared spectoscopy, sulfur and nitrogren determinations, mass spectrometry, nuclear magnetic resonance spectroscopy, and ultraviolet spectrophotometry. Samples were studied from the following selected fields: El Morgan, Egypt; Duri, Indonesia; Minagish, Kuwait; Bachaquero, Venezuela; Gach Saran, Iran; and Prudhoe Bay, Alaska. These samples were chosen to represent high-production fields that are likely to be involved in oceanic transport. Over 50 years of Bureau of Mines analytical research on petroleum served as the basis for evaluation of the experimental results to determine which of the methods are effective techniques to identify crude oil spills. Gas-liquid chromatographic analysis, atomic absorption spectrophotometric analysis, and sulfur-nitrogen determinations are recommended as the most useful of the techniques investigated.

Jan 1, 1975

By T. F. Baily

During the period of the war, in both this country and Canada, a number of attempts were made to make pig iron from steel scrap in the electric furnace, and a considerable tonnage of white pig iron was produced, the silicon and manganese additions being made with ferroalloys; but it is believed that the experiments conducted. at Canton, Ohio, in

Jan 1, 1930

By Andrew R. L

The Kintyre uranium deposit was discovered in 1985 in the course of following up radio- metric anomalies generated in an earlier air- borne survey. The latter survey was conducted primarily to acquire aeromagnetic data for diamond exploration and the uranium discovery was made during a subsequent campaign of base- metal exploration. CRAE commitment to the Rudall area for a range of commodities over a period of 13 years made a significant contrib- ution to the discovery of Kintyre. Other con- tributing factors included CRAE&apos;s multicommod- ity approach to exploration, management support and continuity in the geological team. The Kintyre uranium deposit (Fig. 1) is located on the northern margin of the Rudall Metamorphic Complex, 60 kilometres south of Telfer and 260 kilometres north northeast of Newman, in the Paterson Province of northern Western Australia. It is 700 metres inside the northern boundary of the Rudall River National Park (15695 sq. km) and lies between the Great Sandy Desert and the Little Sandy Desert (Beard, 1969). Intense weathering since the Permian has produced a subdued landscape around the deposit. Resistant rock types still retain an older plateau surface but it is incised by more recent streams. Other Proterozoic and Permian rocks form low, sometimes rocky, areas largely covered by aeolian sand.

Jan 1, 1988

By Onuralp Yucel, Ahmet Turan, Murat Alkan, Hasan Ozer

SHS (Self-propagating High-temperature Synthesis) is one of the important methods to synthesize B4C powders. The process contains the reaction of boron oxide powders (B2O3) with magnesium reducing agent and carbon black carburizer. SHS products are leached in HCl media to purify synthesized B4C powders in the following step. In the present study, effects of various functional additives (KClO3, KHSO4, MgSO4.7H2O, NaCl, MgO and Na2SO4) in the SHS stage were carried out. Various proportions of the additives were mixed with the initial SHS charge mixtures. Two different molar ratios were employed in the initial SHS mixtures as 1:3:0.8 B2O3:Mg:C and 1:2.5:0.8 B2O3:Mg:C. After the SHS step, HCl leaching process was applied to the SHS products. Filter cakes were dried and characterized by using X-Ray Diffraction Spectroscopy, BET and chemical analysis techniques.

Jan 1, 2015

By Jong Hyeon Lee, Go-Gi Lee, Chang-Kyu Lee, Hong Youl Ryu, Sung-Koo Jo

This study deals with research on the reduction process of neodymium oxide by molten salt electrowinning. Neodymium fluoride and lithium fluoride electrolyte were used for feed stock of electrolyte and neodymium oxide was added as precursor. Cell current was confirmed that cell potential was applied as constant potential of 4.5V. Argon gas injection into the electrolyte was carried out to confirm convection effect on current efficiency. Applied current was gradually decreased without argon flow, but applied current was kept within a certain range with argon flow in electrolyte.

Jan 1, 2015