Search Documents

By W. H. Meyer

During the seventeen years Fairchild has been making aerial surveys and aerial photographic equipment many changes and improvements have been made in the equipment and in the technique of using it. Aerial photographic operations have been developed from the crude methods and apparatus of wartime to a science upon which exact engineering calculations can be based. In the early days there was no airplane specially designed to meet aerial photographic requirements. One type of camera was used in all types of operations. Projects were made to conform to the products we could make and deliver. Obviously this entailed definite limitations. We now have airplanes designed specially for aerial photographic operations in accordance with the conditions encountered in actual service experience. We have cameras for every photographic purpose and our laboratory technique and equipment have been developed to the point where it is possible to make contour maps from vertical aerial photographs with contour intervals as close as five feet. Therefore, the selection of equipment now can be made in accordance with the time at our disposal, the justifiable cost, the scale desired, and the general requirements of the client. This does not mean, however, that arbitrary deliveries can be set for aerial photographic products. The factors in each project vary and each job must be considered in accordance with the factors involved. This accounts for the fact that products of aerial surveys may readily vary from $1.25 to $200 a square mile. Sherman M. Fairchild became interested in the design of a radically different aerial camera during the war. At its close he was about ready to demonstrate his design to the War Department. By 1920, he was able to bring out his first completed model. It had a number of radical features, one of which was the first dependable high-speed between-the-lens shutter, which makes for accuracy in aerial photographic work. Another feature was the use of metal throughout, eliminating the wooden parts that had been employed in wartime cameras. Another feature was the interchangeability of parts.

Jan 1, 1937

By T. K. Perkins, W. W. Krech

Jan 1, 1969

The Institute maintains a dual relationship with students: (1) an individual relationship with a Student Associate; and (2) a relationship with local organizations of students, known as Affiliated Student Societies or Student Chapters. 1. The conditions of Student Associateship are set forth in Section 9, Article I, of the Bylaws of the Institute (see page 64 and following pages). During 1934, sundry amendments were made for the purpose of improving the student relationship. Postgraduate students are now eligible; and associateship can be maintained, with the payment of the regular dues of $2 per year, for 18 months following graduation in June. With his regular dues, each Student Associate is entitled to receive during the year his choice of MINING AND METALLURGY, METALS TECHNOLOGY, MINING TECHNOLOGY, PETROLEUM TECHNOLOGY, or two "classes" of Technical

Jan 1, 1943

By D. K. Bose, C. K. Gupta, K. U. Nair

A new approach to processing an indigenously available low made molysulfide concentrate by chlorination with elemental chlorine in presence of oxygen is reported. Recovery of nickel and copper values associated with the sulfide concentrate by suitably treating the residue obtained after chlorination is also reported.

Jan 3, 1978

By G. B. Kasik, George Sachs, George Espey

IT has been reported frequently that the hardness and strength vary over the cross section of cold-worked, particularly cold-drawn, material. Brass rod and wire usually has been found to possess a maximum strength and hardness near the surface.1,2 According to Sachs,1 the center fiber has about the same strength as a wire stretched by the same amount in a tensile-test machine, the strength increasing toward the surface (Fig. I). These differences are particularly large for wire given a small reduction on drawing through a die with a wide opening. However, with increasing reduction and hardness, a tendency to form a thin soft surface skin becomes apparent. On the contrary, copper wire has usually been found to possess a soft surface skin" and it has been reported by Harris3 that during the cold-drawing of hot-rolled wire the surface layer becomes increasingly softer than the core, while the layer of maximum strength moves toward the core, it being found near the surface at first. The increase of strength and hardness from the core to the skin is readily explained by the observation that, in addition to the stretching, the layers of a rod or wire are sheared more the closer they are to the surface.1,6-8 However, the presence of a soft surface layer can be attributed only to an annealing effect. The source of such a softening might be the extremely high temperature that originates from the friction between [ ]

Jan 1, 1941

By G. C. Fryburg, H. M. Murphy

ThE rates of oxidation of metals are usually obtained by heating the metal specimens in furnaces. Such a procedure is satisfactory for most metals. However, there are several metals that oxidize according to the reaction.

Jan 1, 1959

By G. C. Stone

At the conclusion of my paper on the same subject read at the Boston meeting of the Institute, I offered to send some of sample No. 2 to any chemist who wished to analyze it. Eight chemists wrote to me for samples; so far I have received results from five. I give these results in a table (on the following page), together with the results previously obtained: As to the chemists and their methods : K is an iron-works chemist whom I only know by correspondence; lie writes: "No. 27(13.64) was obtained by the method I generally use, as follows : Dissolve 0.8 grams spiegel in hydrochloric acid and a little potassium chlorate, in a half-liter flask. Boil off most of the acid, add ammonia in slight excess, redissolve in acetic acid, using rather more than is really necessary, and then add 8 or 10 grams of sodium acetate and make up to the mark with warm water. Boil hard for fifteen minutes, then allow to settle (cool?), until the liquid reaches the mark, and withdraw 300 C.C. of the nearly clear liquid. Add to this an excess of hydrochloric acid, evaporate to dryness, take up with hydrochloric acid and water, and separate the iron by two precipitations with ammonia (I have often tested the ferric hydrate for manganese, but have never found any, if the separation by ammonia was properly made). Finally, precipitate the manganese as phosphate." Nos. 28, 29 (13.35, 13.07) were by Ford's method." No. 30 (13.50) was by Troilus's method He writes, " I may add the results are quite as good as I expected, although for any element except manganese, they are not close enough for anything like accurate work." L is a firm of commercial chemists of large experience who have made a specialty of iron work. Their method is as follows : Dissolve

Jan 1, 1884

By A. K. Sinha

The market for thermal coal has recently been growing rapidly and it is projected to continue to do so in the foreseeable future. Both the national and international markets often demand high-Btu low-sulfur thermal coal in order to minimize the cost of utilization and meet the environmental restrictions. High quality thermal coal can be prepared to compete in the utility market by desulfurizing the high-Btu midwestern coal and blending it with low-sulfur western coal which is usually low in Btu content. The methods that can be used for optimizing the coal preparation plant operating parameters for physically desulfurizing coal are presented.

Jan 1, 1985

By L. J. West, R. M. Perrry

This chapter describes the rock mechanics studies performed for a high cut at a nuclear power station in Pennsylvania. Two units presently are being constructed on the Susquehanna River. When these units are completed, they will generate approximately 2100 MW of electricity. It was necessary to excavate about 1 million cu yd of rock to prepare the site. This excavation resulted in a high cut on the west and north sides of the station area with a maximum height of about 200 ft. The location of the high cut with respect to the plant facilities is shown on Fig. 1. The recommended slope angles ranged from 1 ½ (horizontal) to 1 (vertical) for the upper residual soil to ½ to 1 for the deeper competent rock. Because of the significant height of this cut and the fact that the slope is immediately adjacent to the proposed nuclear facilities, extensive stability analyses were performed prior to, during, and after excavation to evaluate the steepest angle at which the slopes could be safely cut. The studies consisted of evaluating both qualitatively and quantitatively all apparent factors which could affect the stability of the slopes. These factors include the strength of the material, the zones of weak material which are present along the planes of schistosity, the prominent joint systems, the ground water, and postulated seismic effects. FIELD AND LABORATORY STUDIES A comprehensive program of field explorations was performed to evaluate the geologic characteristics of this site. This program consisted

Jan 1, 1970

The following list contains the names of members of whose deaths notices have been printed in MINING AND METALLURGY during the year ending April 1, 1937. Biographical sketches published in MINING AND METALLURGY are indicated in the last two columns. YEAR OF ELECTION - NAME - DATE OF DEATH - ISSUE CONTAINING BIOGRAPHY - PAGE I892 ALLDERDICE, TAYLOR May 20, I934 1919 ALTMEYER, MAURICE E June 9, I936 1917 ANDERSON, JAMES P Jan. I4, I937 I936 ANDERSON, O RAN M Jan. 12,1937 I908 AUSTIN, E. A I935 1914 BACON, MAURICE W Jan. 4, I936 Apr. I936 22I 1914 BARTHOLOMEW, WILLIAM F Oct. 7, I936 Dec. I936 602 I930 BERRY, HAROLD R July 1, I936 1915 Betts, Robert M Jan. 9, I937 HON

Jan 1, 1937

By H. H. Reamer, B. H. Sage

The formation volume and the relative volume of the liquid Phase of mixtures of Condensate and gas from five different parts of a field in the Louisiana area have been established experimentally. These studies included gas-condensate ratios as high as 25.000 cu ft/bbl at pressures up to 5,000 psi. The gravities of the tank condensates were between 53.9° and 63.9° API. The compositions of the condensate and gas samples inves-ligated are presented in tabular form. The formation volume. the relative volume of the liquid phase. and the specific volume of the mixtures are available. A rough correlation of the formation volume as a function of pressure. temperature, and gas-condensate ratio has been presented. This correlation i-considered applicable only to the range of conditions covered in this investigation for systems of similar nature and com-position. INTRODUCTION Often a knowledge of the influence of temperature. Pres sure, and relative quantities of condensate and gas upon the volumetric behavior of fluid*. from a given field has been employed in estimating the Conditions existing in the reservoir. The early work of Beecher and Parkhurst' and the more rrcent Studies of the Dominguez' and San Joaqnin Valley Field;: are examples of experimental studies of this character. Correlation of the volumetric behavior of naturally occurring hydrocarbon mixtures has Proved To be feasible' . at low gas-conden-sate ratios-; for fluids*. from a single geographic area. Progres 5 is being made in the Prediction of the volumetric behavior of distillate systems at high gas-condensate ratios and pressure.. However. the estimation of the retrograde". ' dew-point pressure still remains uncertain and probably can best be established by experiment. For this reason it appears of interest to make available experimental information about the volumetric behavior of mixtures of condensate and gas from five different part.; of a single field. This material shows a rough similarity to data for mixtures of condensate and gas from San Joaqnin ' Valley Fields. In the present paper. 110 attempt has been made to coordinate the available information on tbe volumetric behavior of fluids from condensate fields. It appears hopeful that progress can be realized by the utilization of recently developed equa-tions of state.!' However. the primary problem in any such correlation is the proper identification of the components and constituents of naturally occuring systems. Additional experimental information may be required to permit the determination of the values of the constants of the equation of state for References given at end of paper. Manuscriptt received in the office of the Petroleum Branch June 11. 1951. *For present purposes low gas- condensate ratios will he considered as those below 3,000 cu ft/bbl, and the region of high gas-condensate ratio will be limited to compositions containing more than 5,000 cu ft of pas per bbl of condensate. Mixtures Containing between 3,000 and 5.000 CII ft OF gas per bbl will be considered of intermediate gas-condensate ratio.

Jan 1, 1952

By C. A. Rowland, M. D. Flavel

There are seven basic comminution circuits that can be used to prepare beneficiation feed from the product of a primary crusher. This paper gives a comparison of these circuits based on average process and economical data. The paper is principally devoted to a discussion of the test work required to obtain the process data needed to evaluate each circuit. The results of the test work in conjunction with geographic and economic factors can be used to narrow down the choice of possible circuits to one, two, or three before making a detailed engineering study.

Jan 1, 1985

By M. F. COOLBAUGH

WHEN I was asked to speak on the subject of leaching, I did not realize that a complete summary of recent progress in leaching had been given by Stuart Croasdale. I shall try to give some other phases of the subject that were not touched by Mr. Croasdale. Not all metallurgists are in harmony as to their methods of treating metals. If they were it would probably mean lack of progress. They can be divided into two classes-the pyrometallurgists, using fire means, and the hydrometallurgists, or those using leaching methods. Conflict is always good for progress; we have it in politics, and in religion there are fundamentalists, and those who are not fundamentalists. As representing pyrometallurgy, may I hope not to be classed among the fundamentalists. The leaching of ores is not new. The leaching of ores for the recovery of metals, however, is quite new. The older leaching was simply to recover the salts. Agricola, back in 1555, I think it was, outlined a great many methods of leaching for the recovery of salts. They called them solid juices at that time. There was no real competition, however, between leaching meth-

Jan 1, 1926

By LESTER H. WOOLSEY

IT IS doubtful whether anything new can be said upon this subject and, therefore, it is with considerable hesitation that l prepare this paper. On account of my recent connection with the Department of State as its law- officer, perhaps I will be pardoned if I discuss this subject briefly from the point of view of that branch of the Government. , I cannot, of course, speak for that department, since I have-no connection with it at-present, but it may be helpful if I set down certain* of the factors which in my opinion and from my experience have a bearing on this international problem. With oil-burning ships, motor vessels, motor vehicles, airplanes-all consuming, astonishing quantities of petroleum or petroleum products; with the United States having within its borders only 12 per cent. of the petroleum resources of the world, and consuming about 70 per cent. of the world's output; with the more enterprising nations wide awake to the necessity ; of obtaining and preserving as large a share as possible of the oil resources extant ; the 'problem is peculiarly and in a, very practical sense an international one.

Jan 1, 1921

By J. E. Burke

Recent investigations have elucidated many of the phenomena of the grain growth process, but have also revealed some conflicting and unexplained results. Beck and his co-workers 1,2,3 have shown that grain growth continues with continued heating at one temperature until the average grain size approaches the thickness of the specimen. Plotting the logarithm of the average grain diameter, D, against the logarithm of the annealing time, t, they find the straight line relationship given by the equation: D = Ktm [,] with possible small deviations at short annealing times. K and n are constants at constant temperature. On the other hand, Wa1ker4 finds that, in alpha brass) the rate of growth falls off more rapidly than indicated by Eq i after long annealing, so that an equilibrium grain size is approached. Burke5 showed, using Walker's data, that time and temperature for grain growth are apparently related through an activation energy, H, according to the relationship: ] where h and tz are the annealing times necessary for the average grain size to increase from Do to D at temperatures T1 and T2 and R is the gas laws constant. In the case quoted, H had the value 60,000 cal per mol. The apparent validity of this relationship, at least up to 700°C, and the approximate value of H were later confirmed by Beck3 The results obtained by Beck Kremer, Demer and Holzworth2 for aluminum and aluminum-magnesium alloys could not be satisfied by such a relationship, since the slope of the isothermal curves increased with increasing temperature. These data indicate and Beck, Holzworth and HuV ater demonstrated expcrimentally that the only apparent factor controlling the rate of grain growth at constant temperature is the grain size. While many of the phenomena have been elucidated, a reasonably quantitative explanation of the process is lacking. There exists uncertainty even as to the primary driving force for grain growth, although there is a considerable body of indirect evidence that the interfacial energy of the grain boundary is responsible.7,8,io Making implicit use of this assumption, several authors14,16 have pointed out that grain boundaries should migrate toward their center of curvature. Harker and Parkerg have advanced this concept furthest, and show that one can expect grain boundary migration to occur only when the grain faces are curved, or when they meet at non-equilibrium angles. When the face is curved toward a grain A, for example, the atoms in the surface of grain B, on the other side of the boundary7 are on the average more surromded by the atoms of their lattice than the atoms on the surface of grain A. Because of thermal motion, the atoms at the interface will sometimes be attached to grain A and

Jan 1, 1949

By G. D. Cody, D. S. Beers, B. Abeles

The thermal diffusivity (thermal conductivity divided by specific heat) of Armco iron has been measured over the temperature range 30º to 1025ºC. The results are in good agreement with the thermal diffusivity computed from published values of thermal conductivity and specific heat, except near the Curie point and at the a to y phase transition, where the measured diffusivity undergoes rabid variations. The differences observed are ascribed to a rapid variation in the electronic thermal conductivity near the Curie point, and a decrease in the lattice thermal conductivity, at the a to ? phase transition. A major difficulty in measuring the thermal conductivity of materials at high temperatures is the determination and elimination of radiation losses. It has been shown, however, that in measuring thermal diffusivity D (thermal conductivity/specific heat) radiation losses can be taken into account exactly.' In order to test the performance of a newly designed apparatus for measuring thermal diffusivity of solids,' we measured Armco iron to an accuracy of 2 pct in the temperature range 30" to 1025°C. This material was selected since both the thermal conductivity,3'4 k, and specific heat,5 C, are known accurately in this temperature range and thus the measured values of D could be compared with D computed from the pub-

Jan 1, 1962

By G. A. Vissac

O. R. LYONS *—I wish to thank Mr. Vissac for his compliment. I hope that his paper is not only well received, but that it will serve to bring forth more papers on the subject of thermal drying. One of the primary purposes of the work performed by Battelle for Bituminous Coal Research in investigating the thermal drying of coal was to stimulate other investigators and to get them to contribute their knowledge in the form of papers such as this one. We at Battelle and the personnel of Bituminous Coal Research are very gratified that Mr. Vissac and other persons have responded in this matter of the thermal drying of coal. I wish to state that I think that Mr. Vissac's paper is a very clear and easily understood description of a method of calculating the design requirements for a screen type drier, and I think that it would be exceedingly valuable to operators and to those who intend to purchase any type of thermal drier and use it in the future, if the manufacturers or operators who have such information for other types of driers would provide the same type of information for the other makes of driers now on the market. 1 also wish to point out—an idea that is new to me, and I know is new to most of the operators of driers in the United States-—the idea of recovering the heat that is normally lost in the coal and in the exhaust gases. This heat is not being recovered at most (of the thermal drying operations in the United States, and the possibility of recovering it should be called to the attention of every single one of those operators. I know many of them have never given any thought to the matter, but they will be interested once they realize the ease with which it could be done and the savings that could be realized. I also wish to compliment Mr. Vissac for presenting the method of analysis that he uses to determine the difficulty of drying any particular coal. It is a very simple method, and yet it seems to me that it should be a very effective, very efficient method for determining the difficulty of drying for his particular problems. C. Y. HEINER*—I do not know that I can add anything very illuminating to what Mr. Vissac has said. I think anything that Mr. Vissac said in regard to coal drying is a contribution because, to my personal knowledge, he has studied the matter carefully for many years and made many valuable contributions. I am not too familiar with coal drying problems in the east, but I know in the west we have not made enough coal drying studies. I think coal operators too often just take the coal as it is and make more or less the best of it. There are relatively few washing plants in the west now, and so the problem has not come to the front as much as it probably will in the future. In this connection, it seems to me that this matter of drying the raw coal, as Mr. Vissac brings up, is an extremely important one. We have not a continuous miner ourselves, yet, but we expect to get some this year, and we think the percentage of fine coal-—that is, minus 3/16 in.—will double. We have about 20 pct minus 3/16 in. in the 8 in. by 0 size now, and we think we will likely have 40 pct, which will have a surface moisture of the order of 8 pct. To wash it satisfactorily, we will have to dry the raw coal first in order to screen it, and after that, I suppose, there will have to be dry cleaning of some sort. We have not really used dry cleaning on fines in the west yet to my knowledge, but it is a matter that has to be faced by the industry, and I am very hopeful that Mr. Vissac's study will assist us in that connection. W. L. McMORRIS*-In my company we are preparing largely metallurgical coal for a great number of byproduct coke plants. The most outstanding thing to me about the requirements of moisture in the finished product is that there is a different requirement for almost every coke plant. Each operator has a different set of factors on which he establishes his coking costs where they involve moisture. For our corporation operations in Birmingham, my company does not produce the coal, but in Birmingham they are getting away with moistures very much higher than our plant at Clairton, Pa., would tolerate. The moisture that we have to produce for the plants along the lakefront where they are subject to much more severe weather is something else again. We have not tackled heat drying, primarily because our customers do not know what heat drying will do to the coking characteristics of the coal. If the temperature of drying can be held down

Jan 1, 1950

I HAVE hitherto shown you as well as I knew how the procedure for those operations which are needed in melting on either a large or small scale, as you might need them. Now I wish to pass on to some other operations which, while related to the operations and power of fires and also to certain kinds of melting, are not wholly connected with the art of casting. First I wish to begin with the actual substance of the art of alchemy, which is sought and desired with so much zeal. Then, as a useful and ingenious thing, I wish to inform you of the art of distilling, and, afterwards, how you should operate a mint in an orderly fashion and without burden on the conscience. Then I shall tell you of the ironworker, the goldsmith, the coppersmith, and some others, as you will be able to see in their places.

Jan 1, 1942

By J. L. Lamon, W. Crafts

P. Coheur and L. Habraken—We read this paper with great interest and are glad to congratulate the authors for their valuable work, supplying an important contribution to the mechanism of tempering on the carbides in vanadium steels. We are in a good position to appreciate this work since we have been studying, for more than a year, Cr-Mo steels of a composition similar, but less highly alloyed (namely 0.1 pct C, 3 pct Cr, 1 pct Mo). Our results are quite in concordance with the authors', however, we wish to point out that it is very interesting to use equally the electron microscope in order to observe the variations of microstructure in steels. We have studied simultaneouslv the evolution of the carbides in situ with the electron microscope, and, after extraction, again with the electron microscope, and then with X-rays. The first results which we have obtained have been communicated at the Congress of Delft (July 1949) and at the "Journbes de la Metallurgie" in Paris (October 1949). These may be summarized as follows: After tempering with varying either the tempering temperatures or the tempering times, the carbides show two evolutions. The first one is connected to the carbides existing in the steels, principally in the boundaries of the grains. For some groups of steels these carbides may coalesce and for other groups they may

Jan 1, 1951

By P. A. E. Armstrong

For hardening, the steel should be heated just above the critical temperature, as a properly forged steel quenched from this heat has some toughness, with maximum hardness and density. The quenching bath should be kept at approximately a constant temperature. In drawing or tempering, longer time periods at lower temperatures are better than the shorter periods at higher temperatures. A recent questionnaire brought out the following facts: The double-arc, double-taper bit and cross bit give the best service; resharpening of the drill steels most frequently was caused by wear of gage; chipping of bit was, with one exception, the second cause; breakage of shank was with one exception, the third cause; upsetting of bit, upsetting of shank, and breakage of body were the fourth cause. The direct cause of the necessity of resharpening given was poor heat treatment first, and faulty steel and severe rock conditions second. Rock-drill Steel By N. B. Hoffman Much of the drill steel produced in America is manufactured into hollow rods. After all forging has been finished the entire bar should be thoroughly annealed and heat trcated before the point is hardened and tempered, at least where the drill has heavy duty, such as working in deep holes and hard rock. A large number of tools of like character and doing work requiring similar properties are now being made of alloy steels; for instance a steel with a carbon content of 0.75 to 0.85 per cent., manganese 0.25 to 0.35, phosphorus under 0.020, sulfur under 0.030 and vanadium 0.18 to 0.23 has proved very satisfactory for chisels. A steel of this type properly manufactured will be far superior to the ordinary carbon steels, while at the same time is one whose price range should not prove prohibitive. Much of the cutting efficiency of a drill depends on proper heat treatment. This vanadium steel has a far greater safe hardening and forging range than ordinary carbon steels, making it more nearly foolproof. It will harden nicely at 1400" I?. but will also harden well and satisfactorily at 1550" F. retaining its quality of hardness and toughness in either case. Drill Steel from Hollow Ingots BY P. A. E. ARmstrong Hollow drill steel is made from a drilled billet with a sand-filled core or the drilled, pierced, or the drilled and pierced billet, not sand-filled, is rolled down over a projectile or ball much the same as in ordinary pipe manufacture. The first is the method generally used in this country; the second is used largely in Sweden. Swedish hollow drill steel has a

Jan 1, 1922