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By Charles S. Barrett, L. H. Levenson

Plastic flow in metal crystals and the changes in orientation resulting from it are generally understood to take place by the following fundamental mechanisms: (1) slip on crystallographic planes, (2) homogeneous crystal rotation resulting from the slip, (3) bending of the 1attice between the planes of slip, and, under certain circumstances, (4) twinning. This paper and a preceding one on iron subjected to uniaxial compression1 concern two additional processes that must now be added to this list: (5) the formation of deformation bands, and (6) the bending and rotation of these bands. The present investigation yields a new understanding and definiteness to the common terms so loosely used when speaking of cold-worked metals —('grain fragmentation," "elongated grains," and "deformation twins," "deformation bands," "etch bands," or "X-bands." Bands have been noted on the polished and etched surfaces of cold-worked metals by various investigators for more than 25 years, ‡ yet their nature and their significance have been so little understood that they are not treated in the most comprehensive modern texts on the deformation of crystals. The experiments in this series show that they are one of the fundamental processes in the deformation of metals, of importance in the development of preferred orientations, in work-hardening (since they have the effect of reducing the effective grain size and interfering with slip), and in the recrystallization process. The present experiments were performed on the same stock of material that was used in the earlier compression experiments1—hydrogen-purified mild steel in which the carbon content had been reduced to the limit detectable under the microscope and in which single crystals could be grown by a strain-anneal treatment.2

Jan 1, 1939

By D. J. Varnes

Rocks in mines, quarries, and many outcrops commonly show evidence of being under high stress. Saw cuts and drillholes close in, partly mined coal bursts violently, and pillars crush and rock spalls in mines even at moderate depths. Similarly, strong and massive rocks such as granite and sandstone naturally divide themselves into sheets that lie more or less parallel to their outward topographic form. The sheets may be either convex or concave. Thin plates of bare rock surfaces bow up and buckle. Such effects often cannot be explained by the obvious loads now acting on the rock, that is, by loads resulting from overburden, topographic irregularities, or stress concentration around openings. The stresses exceed those that would result from such loads. Two interpretations of such excess stresses have been made. In one, the stresses are assigned in origin to now active tectonic forces. In the other, they are regarded as leftover and locked in from some previous state at which higher pressures prevailed. These two sources may both operate and they generally cannot be distinguished easily in the field. There are other complicating sources of stress such as temperature gradients and chemical alteration. Nevertheless, some bodies of rock, by exfoliating, show evidence of high internal stress even though they are practically unweathered and so isolated topographically that the presence in them of significant stress due to exterior loads or active tectonic forces seems unlikely (Fig. 1). Moreover, completely isolated rocks are known to change density, shape, or size 1,2 to expand under constant compressive stress;3 and even to disintegrate 4,5 without the intervention of weathering processes. The stresses involved here must be truly residual in the sense long used by metallurgists; that is, residual stresses in a body are those that remain.

Jan 1, 1970

By Richard F. Miller

Recent studies of creep have made it apparent that plastic deformation may occur in metals under stresses less than the elastic limit as determined from short-time tests. In summarizing conclusions drawn from creep tests by various investigators, Tapselll said: "It is evident that if a material has a true elastic range, the elastic limit must represent the maximum stress for no creep." The presence of a definite elastic limit, represented in single crystals by a critical or threshold shearing stress, is claimed by Schmid2, Elam3 and others who have investigated the plastic deformation of single crystals. However, this "law of critical shearing stress" was determined2 from short-time tests, and the measurement of the deformation was made with apparatus primarily designed to observe large amounts of plastic deformation, not to detect elastic changes. Experimental data recently obtained with highly sensitive instruments by A. W. Hanson4 on zinc and by Podaschewsky5 on rock salt indicate that the elastic range in single crystals is considerably narrower than formerly was supposed. Moreover, a theoretical possibility of permanent deformation, under the influence of even the smallest shear stress in single crystals above a certain temperature (Td), has been developed by G. I. Taylor6. This evidence seemed to warrant an examination of the elastic limit in large single crystals by means of creep tests. The first metal chosen for examination was zinc. AppaRatus The creep-testing apparatus developed for this work is shown in Figs. 1 and 2. The extensometer A is sensitive enough to detect changes in length of 3.3 X 10~6 in. per in., and yet can be used into the plastic range without injury to the apparatus. The specimen,

Jan 1, 1936

By W. Geo. Waring

THE growing need of better methods for the recovery of zinc and other elements from complex sulfide ores has suggested an inquiry respecting a possible group separation of the elements by the aid of volatilization at more or less elevated temperatures. It 'is evident that if the zinc content of such ores can be completely separated, for instance, as pure oxide, by a volatilization 'method, there should be no difficulty in recovering the other elements by smelting and refining. Zinc burning" as applied to zinkiferous ores has advanced but little in practice since the invention of the wetherill grate-furnace process in 1852, as may be seen by reference to papers on the subject.' In other words the thermochemical reaction employed in effecting the volatilization of the zinc is essentially one of reduction by means of carbon, whether the ores treated contain their zinc in an oxidized form, or as the sulfide. The zinc vapors, liberated from the ores at a temperature above that required for the reduction of ZnO by C (about ,1100° C.) or for the volatilization of ZnS per se, (about' 1300°-1400° C.) are subsequently burned to ZnO or to ZnO + SOz, by contact with' atmospheric ,oxygen in the upper or posterior parts of the furnace chamber, or in a so-called "combustion chamber" after leaving the .furnace proper.

Jan 1, 1925

By Chu-Phay Yap

This is the first of a series of theoretical papers on the iron-carbon system. A simple critical analysis of the ordinary constitution diagram of the iron-carbon system yields valuable information regarding the nature of the equilibria in the liquid and solid states. It is shown, for example, that the solute in the melt is Fe3C, but in solid Fe (austenite) the solute is carbon. The thermodynamic laws of the depression in the freezing point of solid solutions have been developed and discussed. Using the usual method of plotting the logarithm value of the concentration of the solvent (in this case, the ratio of concentrations of the solvent in the liquid and solid phases) against 1/T, curves are obtained. A rigorous thermodynamic analysis of these curves has been shown to yield considerable information regarding the internal equilibria of the system, with which the phase rule does not deal altogether. In this way, it is shown again that the solute in the melt is Fe3C, but in the solid rFe the solute is carbon. Various heats of reaction (fusion and transition) and other thermal data have been derived: and discussed with a view to correlating the conflicting experimental data obtained by different investigators of the system.

Jan 1, 1931

By E. S. Porter

The techniques of particle-size measurement are of particular importance in the manufacture of portland cement. A range of sizes, from a close approximation to Fred C. Bond's "theoretical infinite" (represented by raw material in the quarry) to particles smaller than one micron is represented in the process. Moreover, similar size-reduction operations are performed on both natural and synthetic materials, the former relatively inactive in water and the latter quite reactive. This means that aqueous sedimentation systems for particle-size analysis are applicable only to some of the materials involved in the process. A brief review of the process should be useful to place the measurement techniques described here in perspective. (Fig.l) Raw materials are quarried, crushed and transported to storage at a maximum size usually of a few inches. Typical materials are limestone and clay or shale, with small amounts of other materials used to adjust the plant mix to the concentration of lime, silica, alumina and iron oxide required.

Jan 6, 1962

Scientific elite of the Minerals Beneficiation Div. assembled in Denver, Colo., September 17 to 20 to commemorate the 50th Anniversary of Froth Flotation in the United States of America. In his warm address of welcome at the opening luncheon, John W. Vanderwilt, President, Colorado School of Mines, recalled his experience in Bonanza which coincided with the early days of flotation. In those years the scientific and engineering aspects of the process which we know today were little understood and operating the flotation circuit was considered an "art." Luncheon Chairman H. L. McNeill caught the flavor of the old days in an anecdote which recalled the mill nightmares to many present with the agonized words, "Oh God, what's happened to the concentrate now!" It was an appropriate gesture when he called the names of some of the flotation greats for presentation to the assembly; and many an "artist" there was among them!

Jan 10, 1961

By W. H. Emmons

This paper is the third of a series treating of the relations of ores of the metals to igneous rocks. The first' outlined the general problem; the second2 proposed a classification of lode ores, and showed how the distribution of the deposits is in a certain measure controlled by the contour of the roof of the parent batholith. A number of mining districts were discussed, the examples being selected chiefly from group 2 of the classification. The proposed classification of lode deposits, briefly stated, is as follows: 1. Cryptobatholithic: near hidden batholiths which have not yet been exhumed by erosion. 2. Acrobatholithic: in and near cupolas or domes of batholiths—the high points of larger underlying masses. 3. Epibatholithic: on batholiths, near their rims, but below eroded cupolas, or below the highest points of the roofs. 4. Embatholithic: among closely-spaced outcrops which probably are parts of a single bathohth. The outcrops of invaded rocks predominate. 5. Endobatholithic. in and near roof pendants of large batholiths. The invading rocks predominate. 6. Hypobatholithic: in deeply-eroded batholiths, where even roof pendants have been eroded. Deposits of certain metals on the roofs of the batholiths are much more numerous in some positions than deposits of other metals, and the horizontal zonal arrangements of lodes of different metals are shown characteristically only in certain groups. In a large measure, also, the character of the fracturing and metallization is determined by the position on the roof of the batholith. The disseminated copper ores in porphyry constitute a clearly-defined type. All the deposits of these ores, as far as known, are in group 2. They appear to have been formed only in and around small upward projections of the parent granitic masses, and not low on the walls of the

Jan 1, 1927

By J. E. Hackford

IN SOME research. work carried out by the writer, certain results have bean obtained which bear on the fundamental nature and origin of coal and the relationship between coal and petroleum. Without entering into a discussion of the details of the experiments, which were conducted on petroleum and derived bitumens, there are given here, by way of definition, some of the relations that the writer has established between certain classes of bitumens of petroliferous origin. Bitumen.-A natural organic substance, gaseous, liquid, or solid, consisting of hydrocarbons and the oxy- or thionic derivatives of the same, or of a mixture of all three. Diasphaltenes.-Those portions of bitumens that are soluble, in ether or carbon disulfide, but are insoluble in a mixture of equal parts of ether and alcohol. Diasphaltenes are produced by the oxidation or thionization of petroleum oils; they have, as the name indicates, twice the molecular weight of asphaltenes, into which they are converted when subjected to moderate temperature. For example, an artificially produced diasphaltene, which was readily soluble in pentane and ether, was quite insoluble in either of these solvents after heating for three weeks at a temperature of 100° C., and was converted into an insoluble asphaltene. Asphaltenes.-Those portions of bitumen that are insoluble in ether or ether alcohol but are soluble in carbon disulfide. Asphaltites.-Those solid or semisolid natural bitumens that are composed, for the most part, of asphaltenes or diasphaltenes. A pure asphaltite1 would be composed wholly of asphaltenes and diasphaltenes, but most asphaltites contain small percentages of oil and wax, which have not yet been converted into asphaltenes; they may also contain a small percentage of kerotenes, which represent the next stage of the metamorphosis of asphaltenes. Among the naturally., occurring oxyasphaltites may be mentioned grahamite; and among the thioasphaltites, gilsonite.

Jan 8, 1920

By C. E. Lesher

Coal has been fighting a rear-guard action since the last World War. The battle against competitive fuels has been largely guerilla warfare with more sniping within the ranks than of organized opposition. Oil and natural gas are the fuels that over these twenty odd years have driven coal backward and out of many profitable markets. Now, somewhat timidly, the coal industry is trying a new weapon; namely, Research, or let us more properly say, Organized Research. Engineers have been designing this weapon for many years, supported by those interested in coal, including some coal producers. A part of this pioneer work has been Fundamental Research, the Ph.D. kind that is over the heads of most of us. Another part has been aimed at immediate objectives and realizable profits, the practical, man-in-the-street sort. That is Industrial Research. Enough has been accomplished to make a fair exhibit, but whether this new weapon will have sufficient fire power to rout the opposition, whether the industry will really go into production and use it, the next few years will tell. Need foR Coal Research To utter "Research" is to use the modern magic word; to conjure up the miraculous—rubber from weeds; radar; magnesium from sea water; yes, even gasoline from coal. Research is a very general term. It means something different to every man. What is the coal industry seeking with its research; or what should it seek? And, specifically, how is it going about the job; and is it taking the best way? There are many who say that Coal has been asleep at the switch, while Oil and Gas have been taking the energy business. In an organized way this is true. Large-scale, privatelyfinanced research is just started in the Pennsylvania anthracite industry, and it is still a dream for bituminous coal. What has been done so far collectively is purely defensive; as, for instance, to improve mechanical devices for burning coal so as to be able to recover markets for house-heating fuel long since abandoned to oil and gas. To appreciate just how seriously bituminous coal has slipped back in the national economy in the past 2 5 years, one has only to recall that, in the last war the Navy required for its operations all the high-grade, low-volatile coal that could be produced, and that anthracite was withdrawn from the middle and northwest markets to keep the eastern seaboard warm. All coal was "rationed" by zones, if not to individuals. Now the Navy, the Armed forces and the Merchant Marine are propelled by oil and gasoline. Gasoline and heating oil are rationed to individuals. Production of all coal in this country in 1918 reached the historic figure of 678,200,-000 tons, and in 1943, after 25 years, it is expected to reach a special wartime total of 660,000,000 tons. Meanwhile, production of crude oil this year may exceed 1 ,500,000,000 bbl., and like that of natural gas, reach four times the amount produced in 1918.

Jan 1, 1944

By C. E. Lesher

Coal has been fighting a rear-guard action since the last World War. The battle against competitive fuels has been largely guerilla warfare with more sniping within the ranks than of organized opposition. Oil and natural gas are the fuels that over these twenty odd years have driven coal backward and out of many profitable markets. Now, somewhat timidly, the coal industry is trying a new weapon; namely, Research, or let us more properly say, Organized Research. Engineers have been designing this weapon for many years, supported by those interested in coal, including some coal producers. A part of this pioneer work has been Fundamental Research, the Ph.D. kind that is over the heads of most of us. Another part has been aimed at immediate objectives and realizable profits, the practical, man-in-the-street sort. That is Industrial Research. Enough has been accomplished to make a fair exhibit, but whether this new weapon will have sufficient fire power to rout the opposition, whether the industry will really go into production and use it, the next few years will tell. Need foR Coal Research To utter "Research" is to use the modern magic word; to conjure up the miraculous—rubber from weeds; radar; magnesium from sea water; yes, even gasoline from coal. Research is a very general term. It means something different to every man. What is the coal industry seeking with its research; or what should it seek? And, specifically, how is it going about the job; and is it taking the best way? There are many who say that Coal has been asleep at the switch, while Oil and Gas have been taking the energy business. In an organized way this is true. Large-scale, privatelyfinanced research is just started in the Pennsylvania anthracite industry, and it is still a dream for bituminous coal. What has been done so far collectively is purely defensive; as, for instance, to improve mechanical devices for burning coal so as to be able to recover markets for house-heating fuel long since abandoned to oil and gas. To appreciate just how seriously bituminous coal has slipped back in the national economy in the past 2 5 years, one has only to recall that, in the last war the Navy required for its operations all the high-grade, low-volatile coal that could be produced, and that anthracite was withdrawn from the middle and northwest markets to keep the eastern seaboard warm. All coal was "rationed" by zones, if not to individuals. Now the Navy, the Armed forces and the Merchant Marine are propelled by oil and gasoline. Gasoline and heating oil are rationed to individuals. Production of all coal in this country in 1918 reached the historic figure of 678,200,-000 tons, and in 1943, after 25 years, it is expected to reach a special wartime total of 660,000,000 tons. Meanwhile, production of crude oil this year may exceed 1 ,500,000,000 bbl., and like that of natural gas, reach four times the amount produced in 1918.

Jan 1, 1944

By T. F. Archbold, W. H. King

THE diffusivities of gold in polycrystalline copper have been determined in the temperature range from 700° to 1000°C by the utilization of the neutron-activation method. Martin, Johnson, and ~saro' used this method for their investigation of the diffusion of gold into copper at 375° and 550°C for 59 days in order to circumvent the experimental difficulties imposed by the 2.7-day half-life of Au-198. They employed the conventional technique of depositing Au-198 on copper specimens for short-time dif-

Jan 1, 1965

By S. Robinson Brainard

In 1957 the pay of chief executives in the nonferrous metals industry was well above average when compared with other major industries. Furthermore, it continued to rise last year while sales declined 8.2 pct and profits plummeted 32.7 pct on the average. Compensation of Chief Executives: One of the primary objectives of the survey is to measure year-to-year changes in top-management total compensation as it relates to company size and industry characteristics. Total compensation includes salary, bonuses, and the value of deferred contingent compensation awards.

Jan 10, 1958

Steps were taken for a permanent organization of the scientific and technical employees of the Government at their mass meeting on May 8. This was the result of an informal meeting on Apr. 23 of thirty representative Government scientists and technical men who organized the preliminary committee and called the mass meeting. This subject has been widely discussed during the last year and was brought acutely to the fore by the work of the Joint Congressional Reclassification Commission, because that Commission has stated that it wished to deal with employees only through organizations. Rodney H. True of the Department of Agriculture was Acting Chairman. He pointed out that the principal advantages that were expected to be derived from such an organization were: (1) Improvement of conditions and facilities for more effective scientific and technical work; (2) adequate presentation of the needs. and results of such work to the public and to legislative and administrative officers; (3) -greater freedom in both official and non-official activities; (4) just and reasonable salaries based on service performed and the economic and social conditions which prevail; (5) greater public recognition of the aims and purposes of research; (6) advancement of science and technology as an essential element of national life. Three plans of organization were offered to the meeting, which covered the fundamental principles which could be utilized by these Government employees. The first plan would have permitted the new organization to work only through existing scientific organizations. This is the plan that scientific and technical Government employees in England have adopted and an outline of the English plan was read to the meeting.

Jan 6, 1919

By Hsun Hu

NOT much data are available in the literature on textures in cross-rolled metal sheets. Among the body-centered-cubic metals, a few investigators have studied the preferred orientations developed in cross-rolled and in subsequently annealed molybdenum specimens.1-4 Semchyshen and Timmons5 onstructed complete pole figures for the cross-rolled and subsequently annealed arc-cast molybdenum. They used the conventional photographic method. Similar data on cross-rolled iron are still lacking. In view of the fundamental importance of iron as a basic metal for magnetic alloys and many industrial steels, the present investigation was undertaken in an attempt to understand more about its properties. The material selected for the present work was of high purity, and the textures were determined by the Geiger counter spectrometer technique, which permits the construction of quantitative pole figures. Experimental Procedure The material used for this investigation was NRC (National Research Corp.) high-purity, gas-free iron. The total gas content (N2 + O2 + H2) given was less than 0.026 pct, and the carbon content, less than 0.005 pct. Spectrographic analysis of a 2 in. cast ingot showed the percentage of metallic impurities as 0.0004 pct Cu, 0.0002 pct Mg, 0.001 pct Mn, 0.01 pct Ni, and 0.006 pct Si. A 1 in. thick slice was cut off from the 2 in. cast ingot. It was hot-forged at 850 °C to destroy most of the cast structure. Surface scale was removed by milling the forged piece to a size 2 in. long, 1½ in. wide, and ¾ in. thick. After normalizing at 915 °C for 15 min, the piece was alternately cold-rolled 40 pct and annealed at 750°C in hydrogen to a final thickness of 0.165 in., with a resulting uniform grain size of 0.1 mm.

Jan 1, 1958

By E. J. KENNEDY

THE annual dinner-dance was held in the large ball room of the Commodore hotel Wednesday evening. A total of 577 were seated at the dinner, over which President Eavenson presided as chairman and toastmaster. In introducing George C. Stone, the James Douglas Medalist, W. R. Ingalls outlined the former's association with the zinc industry. He said, in part In designing and building Palmerton, Stone erected a metallurgical monument and won the title of chief engineer of the New Jersey Zinc Co., with transferal to its New York office in 1900. There lie held forth in dignity, efficiency, and with appreciation until his retirement from active service in 1929. After a few years lie was diverted from the position of chief engineer for his company to the superior one of chief metallurgist and that gave to Stone his next big chance.... This was the conception of a research department and the ability to persuade his directors to adopt it. I shall not pretend to summarize the great things that afterward developed. I shall mention only the institution of the manufacture of lithopone in this country, the charging of the Wetherill furnace with briquets, the mechanicalization of the Wetherills, the accomplishment of continuous distilling, and most recently the introduction of reflux-refining.

Jan 1, 1935

By J. E. Forciea, O. E. Palasvirta, L. G. Hendrickson

All pilot and commercial plants working with Mesabi Range taconite employ wet magnetic separation. Progress is being made with a dry magnetic process,9-11 but this has not yet been applied to taconite except in the laboratory and pilot plants. Flowsheets in all five plants are similar, including multiple stages of grinding, each followed by magnetic separation, which rejects a finished tailing. The flowsheet in Fig. 1 is used in the preliminary and commercial plants of the Erie and Reserve mining companies and in Unit C of Oliver's Pilotac plant. At Erie the desliming operation is omitted. In the Reserve plants two ball mills are used with each rod mill. Pilotac uses flowsheet 2 in Unit A-B and has also tested flowsheet 3. Principal differences in the three flowsheets are the number of grinding stages and the type of roughing. The terms open- circuit roughing and closed-circuit roughing are best defined by the diagrams.

Jan 12, 1958

By E. D. Gardner

Introduction Oil shale deposits have been exploited in various countries throughout the world, but generally with government aid. The oil-shale industry of Scotland perhaps is the oldest and best-known; the largest was conducted in Manchuria by the Japanese during World war 11 as a source of liquid fuels for military uses. In general, foreign oil-shale deposits that have been exploited are much lower grade than those in the western United States. Considerable interest began to be shown in western oil shales in 1916; the peak of activities was in 1923. The catlin operation, near Elko, Nevada, perhaps was the nearest approach in this country to an oil-shale enterprise on a commercial scale. Over 100 companies were formed, ostensibly for exploiting the oil shale; a large number of them, however, proved to be stock promotions only, which gave the embryo industry a black eye. The Bureau of Mines operated an experi-mental oil-shale retort plant near Rifle, Colorado, from September 1926 to June 1927 and again from April 1928 to July 1929, after which the plant was dismantled. By this time the East Texas oil fields had come ill and the country lost interest in substitute liquid fuels. During World War II the Nation again became concerned about the magnitude of its petroleum reserves. Congress (April 1944) directed the Bureau of Mines to build and operate demonstration plants to produce synthetic liquid fuels from coal, oil shales, and agricultural and other products; a five-year Program was authorized. *' a part of this program the Bureau of Mines has built, at Anvil Points near Rifle, Colorado, a retort plant and develOped an experimental mine to supply the plant with oil shale. An important part of the mining work at Rifle is to devise methods and select practices for mining the oil shale on a commercial scale at the lowest practicable cost. The product to be mined has a relatively low value, a fact that must be kept in in mind. The combined aim of those in charge of the mining and those in charge of retorting is to demonstrate that the shale oil can be produced at a cost per barrel corresponding to the current quotation for crude petroleum —or at least very close to it. Plans call for an uninterrupted flow of broken oil shale from the lace in the mine, through crushers, through the retorts and thence to the disposal dump. The disposal of the spent shale in the Ride area should present no unusual problem. Mining research has consisted so far of Paper studies of the general phases of the probleml determination of the widest Span that the roof Stone will stand safely unsupported, and drilling problems. underground development has not proceeded far

Jan 1, 1949

By L., Ormsby

DRILLING and blasting practices in the Morenci open pit have undergone considerable modification in recent years. Changes in the character of the ground being mined, modifications of working conditions, and continuous experimentation have been the contributing factors.

Jan 1, 1950

By Carl S. Westerberg

Coal preparation practice and trends follow, among other factors, production trends in any given area. Considering an area the size of a state, some broad predictions may be made after a review of the annual production records. As this paper is concerned with coal cleaning in Utah, data on its production record are pertinent. Table 1 shows the percentage relation of coal production in Utah to the national total as a single figure up to 1935 which includes all recorded production. From 1935 through 1947 these data are presented by years. It is evident from these data that the production of Utah coal is ascending. The reason for this trend is industrial growth in the West resulting in a population shift which accounts for more people than the normal increase would supply together with Utah's relatively fortunate geographical location and its abundance of good-quality coal. Utah is also hopeful of supplying more coal in the future for West Coast power generati0n.l

Jan 1, 1949