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By L. O. Storey

The McDermitt mine was found as a separate mercury ore-bearing occurrence approximately 305 m (1000 ft) northeasterly and in a different geologic setting from the old Cordero mine, which had been the district's major producer. The following briefly describes the discovery of the new deposit and the Placer Amex lnc. involvement. The Cordero mining property was under lease by Sierra Mineral Management from the owner Fred H. Lenway in February 1971, when the property was brought to the attention of Placer Amex Inc. (known at that time as American Exploration and Mining Co.) by Richard F. Hewlett of Sierra Mineral Management. The property was first examined by Amex geologists in the spring of 1971, who reported favorably on the project. During that year, Sierra Minerals Management had retained Dr. Larry Walters as a consultant. He proceeded to drill test mercury soils anomalies which he had found northeast of the old Cordero mine in an area overlain by recent alluvium and gravel. An area known as the D area was subsequently blocked out and ascribed a tonnage of about 18 1 kt (200,000 st) which occurs in the vicinity of the eastern edge of the currently defined McDermitt ore body. This mineralization was found in flat lying mercury-bearing lakebeds, unlike the steep structurally controlled ore which was mined in the old Cordero mine. It became apparent to Placer Amex that since the chances of much more extensive ore were good in such a geologic environment, additional exploration was warranted. A joint venture was formed in October 1972 by American Exploration and Mining Co. and Sierra Mineral Management to further explore the Cordero property. The project exploration was fully funded and managed by Amex. Sampling began by Placer Amex in the D area where an open trench had exposed the lakebed ore. Visible cinnabar could not account for the high-grade mercury assays taken from the trench, and an unknown mercury mineral was suspected. Subsequent work established the presence of a chlorine-bearing mercury sulfide which may have enriched the lakebeds as a secondary supergene mineral. Early identification of the mercury-bearing mineral corderoite (Hg3Cl2S,) aided in the geologic concepts for the ore occurrence and was helpful in exploring for the expansion of the D area. Corderoite was found occurring with cinnabar in the lakebeds, and in places it is a major contributor. Specimens of the unique ore were given to Dr. Eugene E. Foord and Dr. Pieter Berendsen at Stanford University, who subsequently identified the chemical and crystallographic makeup of the new mineral and described it for the first time as a naturally occurring substance. Metallurgical work on mercury recovery from the newly described mineral was carried out by the Placer Development Ltd. laboratories in Vancouver, and an acceptable recovery system was worked out together with a planned mill design. Step out drilling from the D area by Placer Amex Inc. encountered extensive flat lying lakebed ore. The McDermitt ore body, as subsequently defined by drilling, was found to contain 2.7 Mt (3 million st) of open pittable ore, containing approximately 5 kg/t (10 lb per st) Hg. The ore body gently dips to the north and is found lying mainly in claybeds just above an opalite breccia blanket which overlies the earlier volcanics. Some ore is also found in the opalite breccia. The mine and mill were constructed under an operating joint venture with Placer Amex Inc. and Sterling Mineral Ventures, and production began in June 1975 at the rate of 20,000 flasks per year. The mine is currently in progress.

Jan 1, 1985

By William Alden

A GREAT landslide occurred on June 23, 1925, in the valley of Gros Ventre River, about 35 miles south of Yellowstone National Park (Fig. 1). The relations of the north-easterly dipping rock formations of the slide scarp and of the dam formed by the slide are shown in the diagrammatic cross-section of the valley (Fig. 2). This generalized section is based on unpublished maps and notes by Eliot Blackwelder, in the files of the U. S. Geological Survey. FIG. 1.-MAP SHOWING SCARP AND DAM (LARGE DOTS) AND LAKE (CROSS-LINED) FORMED BY LANDSLIDE BLOCKING GROS VENTRE RIVER. (Scale 1, in. = 1 mile; contour interval 100 ft. From Grand Teton and Mt. Leidy topographic maps). Heavy rains and melting snow in the Gros Ventre Mountains had saturated clay layers in the Carboniferous strata, which dip toward the valley at angles of 18° to 21°, consequently an enormous mass of rock at the end of the north spur of Sheep Mountain became loosened and, on the afternoon of June 23, slid suddenly down into the valley. Within a few minutes this mass of debris-estimated as 50,000,000 cu. yd.-carrying

Jan 1, 1928

By Merton C. Flemings, Harold D. Brody

Analyses that include diffusion of solute in the solid phase are formulated to describe solute redistribution in dendritic solidification of metallic alloys. The analyses are based on conditions that include negligible undercooling before nucleation of solid phases, negligible increase of solute in advance of the tips of growing dendrites, complete diffusion within the liquid over distances the order of dendrite spacings, and a plate-like dendrite morphology. The classical nonequilibrium freezing equation, Cs = kCo(I - fS)k-l accurately describes solute redistribution between dendrite arms for the solidification processes considered, provided diffusion in the solid is negligible. To account for the effect of diffusion in the solid, an analytic expression is given which is similar inform to the classical expression. 172 addition, a numerical-analysis procedure is etnployed to examine in more detail the effect of diffusion both during and after solidification. The analyses are intended for application to solidification of castings and ingots to describe a) final solute distribution after solidification and cooling to room temperature (microsegregation) and b) local fraction solid as a function of ternperatcre within the solidifying casting or ingol. SOLUTE redistribution in cellular and dendritic solidification has been discussed quantitatively in recent papers'-3 and in a series of earlier work.4-6 However, none of the analyses developed have permitted close correlation of theory with final solute distribution (microsegregation) observed in castings and ingots. In this paper, discussion is given of approximations which may reasonably be made in mathematical treatment of microsegregation, and analyses are presented based on these approximations. Numerical results are given for Al-Cu alloys. In a second paper the analyses will be compared with exeriment.7 CLASSICAL ANALYSIS The classical quantitative treatment of solute redistribution within a closed "volume element" has been derived repeatedly, for example by Gulliver,4 Scheil,' and Pfann.' This "classical nonequilibrium solidification equation" is written for constant partition ratio: where Cs = interface composition of the solid when the weight-fraction solid within the "volume element" is fs (weight fraction, wt pct); k = equilibrium partition ratio; Co = initial alloy composition within the volume element (weight fraction, wt pct). Assumptions of Eq. [11 are: 1) There is negligible undercooling before nuclea-tion, or from curvature or kinetic effects. 2) There is no mass flow in or out of the volume

Jan 1, 1967

By Anson Hayes, John Chipman

The quality of sheet and strip products made of rimming steel is closely related to the structure and chemistry of the ingots. The variation in composition throughout the ingot, as affected by segregation, is of great importance, as are also the form and distribution of the voids that result from the gases evolved. It is because of this importance that the considerable literature in this field has accumulated. No attempt is made in the present paper to compile a bibliography of the excellent work that has already been done, as this has been adequately covered in the many excellent reports on the heterogeneity of steel ingots prepared by a joint committee and published by the Iron and Steel Institute.' From time to time, in any field of investigation new tools and new technique are developed, which make further progress possible. In the field with which this paper is concerned, this is true. The development of the vacuum-fusion method as a means of following oxygen segregation, and a technique for obtaining the volume and composition of the gases evolved during solidification, have opened the way to obtaining data by means of which some considerable progress has been realized in developing more of the detailed mechanisms of solidification and segregation in rimming-steel ingots. General Theory of Segregation The basic cause of segregation lies in the fact that the impurities are less soluble in solid than in liquid iron. The solid that forms from the impure liquid is more nearly pure than the liquid itself. If solidification proceeds slowly enough, or if the liquid and solid phases are maintained in contact with one another for a sufficient time, a condition of equilibrium is set up, which may be represented by a phase diagram. Portions of the

Jan 1, 1939

Alfred Stansfield, Montreal, Canada:—In Professor Howe's paper on the position of Ae3, he shows its industrial importance in determining the temperature to which steel should be heated for " grain refining." Several years ago I carried out a research on the " burning " of steel and found that while hypo-eutectoid steel should be heated to Ae3, hyper-eutectoid steel that has been very much overheated must be reheated to the curve Sa on the carbon-iron diagram, in order to redissolve the pro-eutectoid cementite and thus to obtain recrystallization and grain-refining. This treatment was necessarily only partly successful, and I should like to ask whether the conditions of heat treatment for refining overheated high-carbon steels have been ascertained. Speaking of the &'Persistence of Solidificational Segregation " Professor Howe quotes an experiment made by Mr. Stead in which a bar of 1.2 per cent. carbon steel was immersed in a large mass of molten blast-furnace slag and allowed to cool with it. The steel was heated ; above the solidus (curve An on the carbon-iron diagram), but below the liquidus (curve AB). A drop of eutectic carbon-iron alloy, rich in carbon, had liquated out and hung below the bar. This agrees exactly with my own observations on the burning of steel, but my interpretation differs somewhat from that of Professor Howe. Professor Howe considers that the fusion of a part of the metal (rich in carbon) shows that the solidificational irregularities of composition had persisted through the rolling and heat treatment of the steel, as otherwise no part of the steel would have been sufficiently fusible to melt. It does not appear to me that such an explanation is necessary. A piece of steel represented in temperature and composition by any point within the area ABa will ultimately resolve itself into a solid phase and a liquid phase in equilibrium with each other. It may appear that if the steel were absolutely uniform no fusion could take place, but, the smallest nucleus of high-carbon, fusible alloy would ultimately bring about this separation into liquid and solid phases, by diffusion of the carbon from the solid to the liquid areas. A nucleus sufficient for the purpose might be provided by an area of pro-eutectoid cementite which had not become diffused during the

Jan 1, 1914

By W. P. Sykes

SEVEN years ago, Dr. S. L. Hoyt1 presented a masterful discussion of the hard metal carbides and cemented tungsten carbide. His lecture summarized most of the data then available in the field; many of the details relating to the production, properties and structure of cemented tungsten carbide had never been previously published, for, in fact, this information was only then being acquired. During the intervening years, the cemented carbides have assumed a place of real importance in the commercial field, with an ever widening variety of applications due to constant improvement in the control of production technique and the unremitting search for new compositions that might better the performance of the alloys in one or another type of service. The most recent summary of production methods, properties and guides for the successful application of the cemented carbides appears in the 1936 edition of the Metals Handbook. Of necessity, much detailed information relating to structures and physical properties is not included in such a summary, and it is with such details that the present discussion is concerned. STEPS IN PREPARATION While the past 25 years have contributed a valuable store of working knowledge in the field of powder metallurgy, many of the process controls are derived entirely from experience and are not as yet finally explained by a specific physical or chemical phenomenon. For most of the cemented carbides such difficulties are aggravated by our lack of knowledge not only of the complex alloy systems involved, but also by the possible changes in structure and even in composition which may accompany variations in temperature, heating time, and furnace atmospheres. The principal steps in the preparation of these cemented carbide alloys are fairly well known, but to supply a foundation for discussion these steps are briefly outlined as follows: 1. Formation of the metal carbide in the form of powder by heating a mixture of carbon and the metal powder or oxide for several

Jan 1, 1938

By William Phillips

This paper was prepared at the request of Capt. A. F. Lucas, Chairman of the Institute's Committee on Petroleum and Gas, as a preliminary discussion of the fuel oils which are used-in the Southwest, giving their composition, uses, prices, etc. Should it afterward be found desirable, these observations may be extended over a larger area. In this connection, J suggest that samples of all kinds of fuel oils, including various tars, from all over the country, be collected and sent to some testing laboratory for examination. We would be glad to extend the facilities of the laboratory of the Bureau of Economic Geology and Technology, at the University of Texas, for this purpose, and to do the work free of all expenses. After such examinations are made and the results classified and studied, it would be possible to suggest specifications under which fuel oils should be purchased, and to arrive at some conclusions respecting the uniformity of such specifications, with due allowance for climatic and other more or less local conditions. While such specifications do not now depart from a common standard anything like as much as specifications for illuminating oils do, yet there are discrepancies which should not exist. Some of these discrepancies are of lessening importance, due to the pronounced tendency to distill every crude oil that can be distilled with profit, and to send residues into the market for fuel oil. Residues from the refineries are of a more uniform chemical composition and physical nature than many of the crude oils that go direct into the fuel market. The lower flash-point oils are disappearing from the fuel trade and in place of them we are getting oils that do not flash below 220° F., nor burn under 320° F. In the Southwest, it has not been long since we had fuel oils that flashed at as low as 110° F., and the average flash point over a considerable period was 151° F. Now we are using oil that flashes at about 30° lower than the former burning point, which was 256° F. In other words, the flash point has risen, on the average, 100°; and the burning point about 75°.

Jan 6, 1914

By Albert Sauveur

IT WAS in June, 1889, that I was first admitted to the society of educated men. The admission ticket had been signed, on the recommendation of my old and beloved teacher, Bobby Richards, by General Francis A. Walker at the time President of the Massachusetts Institute of Technology, an institution familiarly known as M. I. T. I immediately proceeded to take advantage of that privilege by departing for Steelton, Pennsylvania, where I understood I was eagerly awaited by the educated officials of the Pennsylvania Steel Company. I was some. what disappointed at the casualness of my reception and at being tucked away in that preserve closet of steel works known as the chemical laboratory. At Steelton I met Major Bent who was president of the company. When I say "met," that is a figure of speech as my acquaintance with him was confined to my being shown

Jan 1, 1937

By E. Maltby Shipp

YouR committee's secretary submits the following report, or summary, to the members of the committee, in an endeavor to lay before them a general review of the information so far received and also his own knowledge of the work as carried on at a number of plants, this being done in part to secure further information and suggestions from members and lead to a more effective means of furthering the work of the committee. It is suggested that more detailed data be compiled regarding engineering features involved, and that papers be contributed which will deal with the safeguarding of underground electrical installations. There are few operating companies which have not started a more or less systematic campaign to safeguard their employees from accidental injuries and unhealthful surroundings, but a great deal is to be gained by experience. All may welcome the advice and cooperation of those who have been actively engaged in the work and have demonstrated the results obtainable by organized effort, and it is, therefore, exceedingly gratifying to note the ready assistance and hearty cooperation rendered by the companies that may be truly termed pioneers in the movement. No solution of the safety problem is to be found in a skrict standardization of methods, rules or devices, as the various mining, milling and metallurgical practices present too many conditions differing broadly in general principles, but some standard system embodying principles already proven to be efficient should be created, which may be modified or elaborated to meet specific requirements of each individual company, or to fit working conditions as they exist in the various mining camps throughout the country. An industrial plant is primarily a business undertaking, therefore the economic side of a safety or welfare campaign is of importance. Many small operators have been deterred from undertaking the work by their belief that it involved an expense beyond their means, and one that could not be counterbalanced by greater efficiency or saving along other lines. This idea is generally due to a lack of knowledge of the actual costs of such work, and of the results secured by judicious selection of a method commensurate with the size and nature of the opera-

Jan 1, 1918

By K. E. Starling

Phase equilibria data were used to develop an equation-of-state correlation for complex hydrocarbon mixtures, thereby circumventing difficulties associated with use of pressure-volume-temperature data. Equilibrium phase data for two condensate reservoir fluids were used to determine equation-of-state parameters for hydrocarbons as heavy as C22H46 in a modified form of the Benedict-Webb-Rubin equation of state. Comparative tests of K-values from the resultant correlation were made with data for condensate reservoir, separator and gas plant absorber mixtures. Generally, for temperatures above OF and computed liquid densities below 0.55 Ib-mole/cu ft, the modified BIVR equation predicted K-values in close agreement with the experimental data. INTRODUCTION Accurate predictions of thermodynamic behavior for complex hydrocarbon mixtures are necessary for many calculations in the petroleum industry. Because of the relatively high cost of extensive experimental data, many correlations for prediction of phase behavior have been developed. Some of these, such as the correlation of K-values presented in the NGAA Equilibrium Ratio Data Book, are totally empirical.l Others, such as the Benedict-Webb-Rubin (BWR) equation-of-state method, are semitheoretical.2-4 Unfortunately, published correlation methods often do not accurately predict the phase behavior of complex hydrocarbon mixtures, principally because of inadequate representation of the effects of components heavier than decane. This paper presents a new approach to this problem in which basic equation-of-state relations including heavy hydrocarbon effects are applied. Equilibrium phase data for two condensate reservoir fluids containing hydrocarbons as heavy as C22H46 are used to correlate component K-values. The BWR equation was chosen as the prototype equation of state for this study because of its proven capability for accurately predicting phase behavior and thermodynamic properties of light - hydrocarbon mixtures? Research was directed toward development of BWR parameters for the heavy hydrocarbons and modifications of the mathematical form of the BWR equation for application to complex hydrocarbon mixtures. The new equation-of-state approach presented differs considerably from previous methods in that phase equilibria rather than PVT data are used for determination of equation-of-state parameters. It is an explicit approach since the parameters are determined directly from mixture data. As such, it does not encounter problems inherent in the implicit method used by Benedict, Webb and Rubin 2-4 and numerous other investigators—one in which mixture parameters were postulated to be functions of the pure component parameters. The pure component BWR parameters, in turn, were determined from experimental PVT data. This method has been limited to mixtures containing components lighter than decane because of lack of vapor phase PVT data. Studies have been reported in which BWR parameters have been determined explicitly from PVT data for binary mixtures.6-8 However, since small concentrations of heavier components have only a minor effect on PVT behavior, it is doubtful that these explicit methods would yield useful results for condensate systems. Ellington and Eakin9 have shown that the accuracy of K-values predicted by an equation of state developed from mixture PVT data probably would be more than an order of magnitude lower than the accuracy of the PVT data. On the other hand, an equation of state utilizing parameters developed from phase equilibria data should predict K-values with accuracy comparable to the accuracy of the experimental phase compositions. This work applies this explicit approach with the objective of improving hydrocarbon mixture phase behavior predictions. Results are evaluated by comparing predicted and experimental K-values at reservoir, separator and gas plant

Jan 1, 1967

By H. H. Stoek

THE fundamental reasons underlying the choice of a method of mining a coal seam are safety of operation, cheapness of producing the product and the character of the product as a saleable article. From the standpoint of safety, open or strip coal mining is always preferable, as many of the dangers inherent to underground work are absent, such as explosions of gas and dust, falls of roof and coal, and also to a great extent those due to haulage and the use of explosives, thus eliminating three of the chief causes of accident from which about 75 per cent. of the underground accidents in coal mines occur. The conditions under which coal is stripped also make the work much safer than ordinary quarry work, as the depth. of the pit is usually comparatively slight. From the standpoint of low mining cost, there is much misapprehension and many of the costs given are misleading in that they do not take into account such items as the destruction of the surface for future use, the full cost of the removal of the overburden, depreciation, amortization, coal depletion, loss of time through floods and from bad weather in winter, etc. Coal is no doubt often put on the cars at less cost by stripping than by underground mining, but by no means always so, as is too generally assumed. In some cases coal must be obtained by stripping or not at all, due to the small amount of overburden that renders underground mining impossible.

Jan 9, 1917

By J. E. Howard

On Aug. 25, 1911, a rail failed on the Lehigh Valley Railroad, causing a disastrous wreck. The surface of the fracture was in a plane at right angles to the length of the rail. There was a dark-colored, oval spot on this surface, located on the gage side of the head, representing the part of the rail which was the first to fracture. The nucleus of this spot showed that the fracture had an interior origin. Other fractures of this kind, the peripheries of which had not reached the surface of the rail, presented surfaces having a (silvery luster. The darkened surface of the present fracture was caused, doubtless, by the air having had access to it. This fracture was recognized as a fatigue fracture, of a modified type, its interior origin having been due to a component in the rail which is not usually present in cases of fatigue fractures. The metal next the running surface of the head of the rail was in a state of internal compression, this being the component not commonly met with in other cases, and which caused the fracture to have its interior origin. For the purpose of giving this modified type of fatigue fracture a specific name, for identification, the term "transverse fissure" was applied. No mystery was thought to attach to its formation, or to its development. The explanation of its occurrence seemed obvious in the light of common knowledge upon the behavior of steel under repeated alternate stresses.' By reason of the state of internal compression at the running surface, the maximum tensile stresses in the head, ander bending loads, were along an interior element. Here the tensile strains were higher than in the fibers more remote from the neutral axis. Under such conditions the fracture of the rail would be expected to have an interior origin. A discussion of the subject of transverse fissures essentially becomes a discussion of fatigue fractures, since they are believed to be identical. The descriptive term employed, merely for the identification of this type of fatigue fracture, had the appearance of creating alarm. Apprehensions arose that a new phenomenon in the physical properties of steel had presented itself, the explanation of which was sought in every

Jan 1, 1918

By J. Murray Riddell, Arthur E. Anderson, Grover J. Holt

OUT of the depths of each business cycle we emerge with a stimulus for greater efficiency and a realization of progress in industrial technique. The recent years have not been an exception to this rule, and in retrospect we sense that significant advances have been made in mining practices on the Mesabi Range, with emphasis on speed of production and economy of operation. A survey of such changes does not reveal anything that is fundamentally or basically new, but it is apparent that ideas and machines that have found wide application in industry elsewhere, with necessary modifications, are being put to productive use in mining iron ore. Innovations in transporting and conveying ore from the open pits stand out with greatest prominence, so that, in the main, it will be with these features that this paper will treat, in the review of progress made to this date. The late years have witnessed the development of small deposits for open-pit operation, the cleaning up of pits nearing exhaustion, and in two large operations the approach to the limit for haulage by steam locomotives, owing to grades, making it necessary to recover the ore in slopes, track benches and below the power-shovel limit by a milling and scram operation. For several years small standard-type dump trucks have been used in clean-up or scram operations within the pits, but during the seasor1 of 1936 the first effort was made to use heavy truck haulage in the transportation of stripping and iron ore. The new units in use today vary from 15 to 20 tons in capacity, and are equipped with powerful gasoline or Diesel engines and supplemented by trailers or wagons on rubber or crawler treads. The Diesel engine finds favor with most operators because of fuel economy. These units develop upward of 125 hp. in the 15-ton trucks. The speed of these trucks varies from 2 miles per hour in low gear to 35 in high gear. The transmission affords 12 speeds forward and 3 speeds in reverse.

Jan 1, 1938

By W. A. Riggs

In a single year the total transportation cost equals nearly 30 pct of the value of mineral commodities, the largest single cost from the deposit to consumer. The magnitude of this economic factor calls for more complete understanding of cost and operational problems between producer and carrier than now exists. Details are given of the costs of providing transportation as well as freight rates for selling transportation. In 1958, transportation of mineral commodities in the United States required 600 billion ton-miles to move 1 3/4 billion tons of products of mines comprising solid fuels, crude oil, industrial minerals and rocks, and ores. Possibly 17 pct was handled by more than one mode of transport, since combinations of several modes of transport may, at times, achieve better service/cost results than any single mode. Total transportation cost of nearly $5 billion equaled roughly 30 pct of the value of the mineral commodities, the largest single cost from the mineral deposit to the consumer. The tremendous magnitude of this transportation undertaking demands much more complete understanding than now exists between mineral producers and carriers about the economic and operational problems of each other. A substantial portion of the daily work of the writer is spent in trying to act as a combination interpreter and catalyst between potential shippers and carriers, hoping to direct both to points of mutual understanding and advantage. For the purpose of this paper, it is necessary to ask mining people to accept some terminology and to try to appreciate the mental approach of the freight rate making people of the carriers. This paper will consider costs of providing transportation as well as freight rates for selling transportation—although these are fields of limited certainty. There are no accurate statistical breakdowns for all modes of transport and types of carriers indicating commodities, volume of traffic, distances, costs, and rates. Much information is available for railroads, and some for the regulated portions of air, motor, pipeline, and water transportation. Unregulated carriers, handling about half of the transportation of products of mines, are not required to report, and very little is known of their activities. Figures used herein are national in scope, unless otherwise indicated, and have generally been derived from Interstate Commerce Commission reports and files. Tonnage figures have been reduced to net tons of 2000 lb. The very generalized comparison of average mileage freight rate levels for various modes of transport provided by Fig. 1 affords advantageous perspective for the entire field of transportation costs. Dashed guide lines show cents per ton-mile, and dotted guide lines show percentage of first class railroad freight rate. While costs of other than railroad transportation more nearly follow constant cents per ton-mile functions, costs of railroad transportation show characteristic taper, or decrease in cents per-ton mile with increasing length of haul. This fundamental difference in cost is due largely to the fact that railroads and pipelines provide their own fully taxed roadway facilities while highway, waterway, and air carriers use government-provided tax-free roadway at no cost other than fuel, license, and certain excise taxes. Thus railroad and pipeline transportation might be said to carry heavy threshold costs in addition to those transportation costs which are directly variable with ton miles of transportation produced. The original basis of railroad freight rate structures lies in the classification of all articles of commerce into railroad class ralings ranging from 7 to 40 pct of first class (100 pct) rate level, dependent on value, hazard, loading characteristics, service requirements, and whether carload or less than carload. Classification tables and mileage-based (but arbitrarily grouped), rate scales are published as tariffs subject to approval by regulatory bodies. Used together, these determine class rates in cents per 100 lb between points in the U. S. Where local commercial or operating conditions render it advantageous for carriers to depart from

Jan 1, 1961

By Homer Turner

THE nature and comparative features of anthracite and bituminous coals have been discussed by the writer in two previous papers.1 Although this paper is offered as a further contribution to the subject, it seems desirable at the outset to repeat some of the descriptive matter of the early works in order to show the actual connection between various constituents of both coals and the new photomicrographs and other physical and chemical properties.

Jan 1, 1929

By Masatsugu Taniguchi

Onoda Cement Co., Tsukumi is one of the largest limestone producer in Japan. From mines called Suisho and Ganji, it supplies limestone for cement plant, lime manufacture, iron and steel industries and for many purposes. The Suisho mine is highly productive, though it's operations are governed by the utmost regard for its impact on the surrounding environment. However, it became difficult to meet additional expanding demand and to assure continuity of high rate production. Present production rate 1s 6 million tons per year. The Ganji mine, some 2 km south west of the Suisho mine, began first-stage development In mid- 1973 and in january I976 started production. The capacity of major facilities is 9 million tons per year. Full production is predicted in 1979. Mining and milling methods of these mines under strict environmental considerations are discussed.

Jan 1, 1976

By R. S. Archer

BERYLLIUM has certain properties such as low density, high hardness, good corrosion resistance, low thermal expansion and fairly good electrical conductivity, which would indicate that it, is worthy of consideration as an ingredient of light alloys. It was not until recently, however, that beryllium could be produced with sufficient ease to encourage research along this line. The production of beryllium by electrolysis from a fluoride bath has now developed to the stage where it could be used commercially if there were sufficient demand for the element. Claims made in certain newspapers and technical articles in regard to the strength and corrosion resistance of the aluminum-beryllium alloys are not justified by experimental results. Moreover, beryllium is an expensive metal ($200 a pound at the time this work was done) and, on account of the nature of its ore and the consequent difficulty of its extraction, it will in all probability continue to be a relatively expensive metal, although the cost would undoubtedly be a great deal less than $200 a pound if the metal were produced on a large scale. It seemed, therefore, that low-beryllium alloys offered the greater commercial possibilities except for very special purposes. It was partly for this reason that in the present work emphasis has been placed on beryllium alloys of low beryllium content.

Jan 1, 1928

By G. Willard Quick, John R. Freeman

Jan 1, 1930

IN the early period of steelmaking, ingot structure and segregation were of no practical importance. Crucible melting required very small ingots that gave little segregation, and a small inserted hot top prevented pipe. As larger ingots were poured from bessemer converters and open-hearth furnaces, segrega- [ ] tion, piping, and gas evolution became increasingly important. The techniques of making semikilled and rimmed ingots were developed with little knowledge of the actual mechanism of the process. The first studies of solidification were made by the Brearleys1 and Gathmann,2- who used stearine to show the effects of shrinkage and mold shape. Fig 11-1 is a picture of a series of stearine ingots at various stages of solidification. These studies showed that the liquid solidifies at a nearly uniform rate from the sides and bottom of the mold and demonstrated the formation of

Jan 1, 1964

By P. Gobin, J. Perez, P. Peguin

The strain-amplitude- dependent part of the internal friction of alluminum after several ther momechanical treatments has been measured in the I-cycle range and at the ambient temperature. The internal friction in the outer layer of the torsional specimen us stress is computed from the experimental data. The curues obtained are analyzed in tevnzs of u coirzbinntion of AH and p, which aye, respectively, due to the vecersible unpinning from weak pills and to the plastic strain. Considerirlg the notion of thermally activated unpinning and repinning, it is shown that in our experimental conditions tlze dislocation lines acl as in the H model of Granato and Liiclze. It is also seen that the internal friction p which appears at higher- strains call be described by a simple expression which is in good agreement with our results. A qualitative interpretatiorz is proposed by combining these new types of intelpnal fviction. We define the internal friction 6 as half the ratio of the dissipated energy aW during one cycle to the maximum supplied strain energy W of a material submitted to a periodic stress. Experiment and theory show that internal friction varies with stress above a critical value.' Below this value the internal friction is strain-amplitude-independent and is often masked by an experimental background; so we shall call it AB. ~bove this critical value, the internal friction is strain-amplitude-dependent. This quantity is usually called aH:' and it can be explained as a thermal unpinning of dislocations.3-6 Furthermore, at higher stresses, a rapid increase of internal friction appears. This phenomenon could be caused by the plastic strain,' so we shall call it Ap. It seems interesting to us to study the influence of several t her momechanical treatments on the curve internal friction 6 vs strain E, in order to study the variation of AH and p with the concentration and the repartition of linear and point defects. In order to try to explain the results obtained, we shall propose and discuss models for H and hp and shall show that we obtain a combination of these two types of internal friction. 1) EXPERIMENTAL PROCEDURE 1) Preparation and Treatment of Specimens. We

Jan 1, 1968