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By J. David Lowell

For his contributions to the field of mining geology, a striking example being his brilliant inte.rpretation of the complex geologic history of the San Manuel District (Pinal County, Arizona) which resulted in the discovery of the Kalamazoo orebody, and for his lecture, "Copper Resources in 1970." On a low desert ridge six miles south of Cairo lie the remains of the world's earliest known mining town, Maadi of predynastic Egypt. Copper artifacts, including ingots and an ax head which was spoiled in casting, indicate that copper ore was smelted in Maadi, and radiocarbon dating has placed the activity at least as early as 3300 B.C. This is the oldest documented date for the use of smelted copper, the first industrial metal used by man. Copper was mined and smelted almost as early in Asia Minor and on the island of Cyprus, but the greatest development of the budding copper industry was in Egypt, where specific historical records show that about 10,000 tons of copper metal were produced in the period from 1850-1580 B.C. Contrast this production of 35 tons per year with the present world production of about 7 million tpy. Evolution of the Copper Industry The copper ore mined by the ancients was high grade, and the copper produced was expensive. The copper industry began with narrow high-grade veins, but has evolved to the point where massive earth-moving equipment can be operated in huge, low-grade open pits. Indian pits dug before 3000 B.C. in the Lake Superior district were in ore which averaged 15% Cu. His- torical research done by Arthur Brant has shown that copper cost in the Middle East in 1840 B.C. in terms of 1970 labor dollars was about $25 per lb. The copper mined in northern Europe in 1540 in the time of Georgius Agricola averaged about 8% Cu, and the cost in 1970 labor dollars was about $10 per lb. Average ore grade had dropped to about 6% Cu in 1890, and the cost of copper in the U.S. in 1970 dollars was about 45¢ per lb. Butte, Mont., was a good example of the efficiently operated vein mines of this time. In 1906, Daniel Jackling made a dramatic entrance into the copper scene with the Bingham Canyon open-pit copper mine and proved that more profit was possible mining 2% porphyry copper ore on a

Jan 1, 1971

By J. H Lightfoot, Stuart E. Buckley

Deep drilling has led to the development of numerous pools which yield products consisting predominantly of natural gas accompanied by high-gravity water-white or slightly straw-colored liquid. Yields of this "condensate" or "distillate," as it is commonly called, vary from traces to over a hundred barrels per million cubic feet of gas. The fact that this liquid exists in the reservoir as an integral part of the gas phase and is formed by condensation attending simultaneous reduction of pressure and temperature after its entry into the well was apparently first recognized about 1932.l The nature of the physical phenomena involved in this condensation was clarified for the petroleum industry in 1933 by a report by Sage, Schaafsma, and Lacey2 of the results of an experimental investigation of the behavior of mixtures of methane and propane. Search of the literature has revealed that the condensation of liquid from gaseous mixtures by isothermal pressure reduction is not a new discovery. Kuenen was led by theoretical considerations to expect such a phenomenon, and in 1892 reported3 the results of experimental verification of his deductions. This was followed by a considerable amount of work on the phase relations of mixtures by Kuenen 4,5,6 and by 0thers,7,8 mostly in European universities. Since 1930 investigators in this country have reported experimental data on the properties and behavior of a number of hydrocarbon systems."' It is now generally known that in the presence of natural gas the solubility in the gas phase of the heavier and normally liquid hydrocarbons increases rapidly with increasing pressure above 500 to 1000 Ib. per sq. in. Thus, at pressures of 2500 Ib. per sq. in. or higher a gas may contain appreciable quantities of hydrocarbons with normal boiling points as high as 6o0°F., which in turn may be condensed from the gas phase by the reduction of their solubility therein attending pressure reduc-tion. The combined effects of pressure and temperature on condensation and vaporiza-tioi of mixtures are most readily visualized by the study of phase diagrams. Since the construction, application, and interpreta-tion of such diagrams have been described fully in readily available literature, 18-20 this paper will not review the theoretical aspects of this subject. While the behavior of gas-distillate sys tems is now clearly understood, at least in a qualitative way, most of the published work deals with the results of laboratory studies of binary systems or of synthetic mixtures of hydrocarbons, and although several systematic investigations of the effects of separator pressure and temperature on the yields of liquid product from gas-distillate wells have been made21,12z it appears that in all cases the limitations have precluded the construction of even approximately complete phase diagrams for naturally occurring systems. There has 2

Jan 1, 1941

By J. H. Lightfoot, Stuart E. Buckley

Deep drilling has led to the development of numerous pools which yield products consisting predominantly of natural gas accompanied by high-gravity water-white or slightly straw-colored liquid. Yields of this "condensate" or "distillate," as it is commonly called, vary from traces to over a hundred barrels per million cubic feet of gas. The fact that this liquid exists in the reservoir as an integral part of the gas phase and is formed by condensation attending simultaneous reduction of pressure and temperature after its entry into the well was apparently first recognized about 1932.l The nature of the physical phenomena involved in this condensation was clarified for the petroleum industry in 1933 by a report by Sage, Schaafsma, and Lacey2 of the results of an experimental investigation of the behavior of mixtures of methane and propane. Search of the literature has revealed that the condensation of liquid from gaseous mixtures by isothermal pressure reduction is not a new discovery. Kuenen was led by theoretical considerations to expect such a phenomenon, and in 1892 reported3 the results of experimental verification of his deductions. This was followed by a considerable amount of work on the phase relations of mixtures by Kuenen 4,5,6 and by 0thers,7,8 mostly in European universities. Since 1930 investigators in this country have reported experimental data on the properties and behavior of a number of hydrocarbon systems."' It is now generally known that in the presence of natural gas the solubility in the gas phase of the heavier and normally liquid hydrocarbons increases rapidly with increasing pressure above 500 to 1000 Ib. per sq. in. Thus, at pressures of 2500 Ib. per sq. in. or higher a gas may contain appreciable quantities of hydrocarbons with normal boiling points as high as 6o0°F., which in turn may be condensed from the gas phase by the reduction of their solubility therein attending pressure reduc-tion. The combined effects of pressure and temperature on condensation and vaporiza-tioi of mixtures are most readily visualized by the study of phase diagrams. Since the construction, application, and interpreta-tion of such diagrams have been described fully in readily available literature, 18-20 this paper will not review the theoretical aspects of this subject. While the behavior of gas-distillate sys tems is now clearly understood, at least in a qualitative way, most of the published work deals with the results of laboratory studies of binary systems or of synthetic mixtures of hydrocarbons, and although several systematic investigations of the effects of separator pressure and temperature on the yields of liquid product from gas-distillate wells have been made21,12z it appears that in all cases the limitations have precluded the construction of even approximately complete phase diagrams for naturally occurring systems. There has 2

Jan 1, 1941

By MARK H. LAMB

(Canal Zone Meeting, November, 1910.) THE recent growth of a sentiment among cyanide-plant designers against the use of gravity-stamps for the crushing preliminary to cyanidation may be said to date from the almost simultaneous perfection of the ribbed tube-mill liner and of the tall, air-agitation tank. The first step in the resulting change of practice was the universal adoption of the tube-mill for fine-grinding and the use of coarse screening oil the battery. This was the beginning of the surrender of supremacy by the gravity-stamp ; since merely the single fact that it was a more economical machine for crushing fine had retained it in favor as compared with ball-mills, rolls, or steam-stamps. The surrender, however, is not yet complete. It is the universal practice to use rolls where a relatively small tonnage is to be crushed coarse, as, for example, when coarse concentration is included in the plan of treatment. Power, attendance, repairs, and first-cost are smaller for the rolls, under such circumstances, than for stamps; and it is becoming daily more apparent that, with no concentration to provide for, the use of rolls and tube-mills, without the complication of trommels and elevators required by concentration, is rapidly gaining favor in the eyes of the leading designers. The next step was the use of the rapid-running Chilean mill between the gravity-stamps and the tube-mill, which again narrowed the field of operation of the gravity-stamp while radically widening its screen-aperture. Such a combination of stamps and Chilean mill offers advantages when fine concentration is necessary, since the reduction in the Chilean mill call be adjusted easily and governed by varying the screen-mesh. But even concentration is now looked at askance. One of the leaders of this metallurgy has abandoned the separation and

Jul 1, 1910

By Homer W. Riley, C S. Jenkins

SMALL power-driven, toothed, cast-iron rolls were used first to break anthracite in 1844. Prior to that time, men with hammers, who stood on perforated cast-iron- plates, .broke the large lumps into commercial sizes. In order to convert run-of-mine into the various sizes required by the anthracite industry, about 20 million tons must be broken, annually, [ ] into smaller sizes. This phase of anthracite preparation is of major importance, because the degradation accompanying reduction in coal sizes should be kept at a minimum. The exclusive use of toothed rolls for that purpose indicates that comminution by rolls is the best solution of the problem. Many improvements have been made in tool design, but the most important was a reduction of the peripheral speed of the rolls from 1000 to 300 ft. per minute. The higher speed was based upon and approximated the velocity of a falling piece of coal when it entered the rolls. Exhaustive roll tests at the slower speed showed that the same size reduction could be affected with less degradation. The adoption, there- fore, of slow-speed, compound geared rolls, especially for breaking the

Jan 1, 1943

By Benj. Lyman

The Institute, in June, 1881, visited Low Moor in Alleghany County, Virginia, on the Chesapeake and Ohio Railway, seven miles easterly from Covington. Having occasion myself, a few days later, to make a very hasty geological reconnaissance of the iron-ores there, and finding them to be somewhat different in age from what was said to be the opinion of some of those who were there with the Institute, I have thought it worth while to bring the matter up again at the present meeting. According to the opinion quoted, the principal ore-banks belong to the Oriskany sandstone; and that seems to be the view entertained of the same ore in that region by Prof. Wm. B. Rogers in his reports of 1837 and 1838. it is likewise given by Prof. J. L. Campbell in a paper on the Rich-patch iron region in The Virginias for December, 1880 (vol. i., p. 189). A comparison, however, of the section at Low Moor with sections in Pennsylvania, shows clearly that the main ore-bed is the same as that of the bottom part of the Marcellus shales (part of Pa. and Va., No. VIII), a short distance above the top of the Oriskany sandstone (No. VII). The Upper Helderberg limestone is absent at Low Moor, as indeed it is at many places in Pennsylvania, and that is perhaps the reason why the ore has been thought to belong to the Oriskany sandstone. The ores and their accompanying rock-beds, are exposed in three or four folds near the Low Moor iron-mines on Fork Rim and, as described and pointed out by Mr. Geo. T. Wickes, who had in his management of several years' duration become well acquainted with them, are as follows, from above downwards:

Jan 1, 1886

By R. W. Raymond

PROF. HENRY Louis, of Armstrong College, Newcastle-on-Tyne, England, a distinguished member of this Institute and other technical societies, has recently sent to the Institution of Mining Engineers, and to the Institution of Mining and Metallurgy, in Great Britain, a communication, the substance of which is as follows Prof. Louis calls attention to the absence of any recognized English term for the definite description of a frequent phenomenon-namely, the oblique position of an ore-body in the plane in which it. lies. In this connection, Prof. Louis says that in America the term " pitch " has been occasionally applied to this relation, and proposes that, in the literature of ore-deposits, it shall be hereafter restricted to this particular meaning, the angle of the pitch, like that of the dip, being always measured from the horizontal, and the dip being always taken at right angles to the strike, while the pitch is taken on the plane of the dip, in the direction of the strike. Thus, for example, in a vein or bed striking N-S., and dipping, say, 45° E., there might be an ore-body, the axis of which pitched northward, at an angle of 45° below the horizontal line, as measured on the plane of the inclosing vein or bed. If the term " pitch " had this universally recognized meaning, the situation could be simply and perfectly expressed by its use, in connection with the general data of strike and clip. As Prof. Louis says ?This suggestion has a certain practical value, and is not merely academic. Every mining engineer of practical experience in such types of ore-deposit will have met with cases, in which a vertical shaft has been sunk with the object of cutting the deposit, but has missed it, because the dip alone has been taken into account, while the pitch has been overlooked." He adds the acute observation that such an oversight is much likelier to occur with regard to a condition not definitely desig-

Mar 1, 1908

By John Rear Admiral Edwards

Introductory.-There are many interesting and important events connected with the petroleum problem. The remarkable men who conceived the thought of transporting petroleum by pipe line, conserving the by-products of the commodity, and conducting extended investigation and research whereby the flash point of the oil was raised, its cost reduced and its Supply assured, are deserving of the gratitude of this nation. It was primarily the success attained by Captain Lucas, after his comprehensive search for oil in Texas and Louisiana, that was the impelling cause. which 'prompted the Navy Department to conduct the extensive series of liquid fuel-oil tests that were made from 1901 to 1903. The sensational discovery of oil at Spindle Top made a deep impression upon Rear Admiral George W. Melville, then Engineer-in-Chief of the Navy, and the discovery of the vast oil field in Texas convinced him that, within a generation, if not within a decade, crude petroleum was going to play a very important part in warfare, and that the commodity might possibly develop into a necessary munition of war. The United States' Commanding Position as a Petroleum Producer.¬ In the study of the various problems relating to the world's production of crude petroleum, the position of the United States is one of commanding importance, whether viewed from the industrial or the military aspect. The present yield of this country is practically double that of the rest of the world, and, in view of the productive and prospective fields possessed by various countries, together with the comprehensive and exhaustive search that has been made throughout the world for petroleum, it is extremely probable that this lead will be maintained for the next decade. As regards the character of the crude-oil yield of different countries, America possesses the greater part of the supply that contains a paraffine base, and therefore a considerable portion at least of the American product produces the best illuminant. Of all the crude-oil distillates, kerosene is in many respects the most important, and the Appalachian product for this purpose is favored, particularly in the Far East, above that of any other petroleum yield of the world.

Jan 9, 1914

By Dave H. Barnett, Brij M. Moudgil

The flotation technique as employed by Florida phosphate producing companies for the beneficiation of fine phosphate particles has been standardized over the years. Lower recoveries of coarse Phosphate rock by froth flotation technique, however, led to the development of new methods based on skin flotation of phosphate agglomerates. Recent developments of floating coarse rock in large flotation machines have not yet convinced the rock Producers of their higher separation efficiency. It is interesting to note that the selection of a particular machine is still bared on equipment preference by an individual company as well as proven performance of a particular machine for upgrading a specific material. Various techniques which have been developed to beneficiate the coarse phosphate rock have been discussed. Performance of the individual techniques is presented.

Jan 3, 1979

By Arthur Lake

Within the past few months I have had occasion to visit and examine the area of country in Gunnison county locally called the Gold Belt and extending from the Cebolla river on the west to the head of Taylor Park and the Sawatch range on the east. The region including the "belt" may be hided topographically into two parts, a northern and a southern one. The former is characterized by lofty mountains and deep canons, with occasional parks and wide valleys. Most of it is included in the granitic system of the Sawatch range, with local patches of the Palaeozoic sedimentary rocks, more or less traversed by great bodies of porphyry and other eruptive rocks. The southern portion, on the other hand, is characterized by comparatively low, rounded hills of schist and sahistose gneisses, underlain by coarse, massive granite, which outcrops locally in small, and sometimes in large, patches. These hills also sometimes form table-lands by reason of overflows of lavas, such as andesitic breccia, rhyolite, trachyte and basalt. The leading geological feature is that of a schistose area of width and extent unusual for Colorado. These schists and gneisses are of pre-Cambrian age; but whether assignable to the Algonkian or to some older system has not been determined. The granite which occasionally outcrops from beneath these schists is, I think, of true eruptive character, since its mode of occurrence indicates a once molten, or at least highly viscous or plastic, condition. Thus, we may observe, included in its mass, numerous fragments of schist, almost like a coarse, volcanic breccia. Again, at its immediate contact with the schists, which often stand vertically upon it, the pediments of the latter are fused into the granite, and granite tongues and veins run up amongst the schists, as only a molten or viscous

Jan 1, 1897

By Kefton Teague

The minerals discussed in this section have experienced a gradual, although not spectacular, growth in general. Obvious exceptions are the gradual decreasing use of talc and bentonite as filler materials, partly because of availability and relatively lower sales price of competitive materials. Mineral fillers and filter minerals are used principally in those countries that are heavily industrialized. Except for diatomaceous earth of filter grade, most industrialized countries are reasonably self-sufficient in the various filler and filter minerals. Prices of the various mineral commodities during the period 1950-1970 increased approximately as follows: barite, 43%; diatomaceous earth (filler), 49%; diatomaceous earth (filter), 55%; fuller's earth, 55%; talc. 77%; and bentonite, 94%. Actual usage of these mineral commodities as fillers and filters, during this period, showed changes approximately as follows: (1) Decrease-fuller's earth, 6%; talc, 15%; and bentonite, 29%. (2) Increase-barite, 113%; diatomaceous earth (filler), 150%; and diatomaceous earth (filter), -194%. A relationship between the amount of the various fillers and filters used and price increases is apparent. For example, barite increased only 43% in price, but its use as a filler has increased by 113%. On the other hand, talc, which increased 77% in price, decreased in filler use by 15%; and bentonite, which increased 94% in price, has decreased for filler and filter purposes by 29%. The actual decrease in the use of some of these commodities is not entirely caused by an increase in price. Competitive materials frequently have made substantial gains in the various filler and filter markets. For example, much of the bentonite used in the late 1940s and early 1950s for clarification of mineral and vegetable oils has been replaced by competitive materials. BARITE Occurrences and Sources In the United States, barite is produced from about 14 states, listed in approximate order of importance as follows: Missouri, Arkansas, Nevada, Georgia, Alaska, Tennessee, Kentucky, California, New Mexico, North Carolina, Washington, Idaho, South Carolina, Texas, and others. During the 20 years ending in 1970, almost equal amounts of barite were produced from Arkansas and Missouri. Within recent years, Nevada has replaced Georgia as the third leading barite--producing state. West Germany is second to the United States in barite production. Other important barite-producing countries include: Mexico, USSR, Italy, Greece, Canada, and Ireland. Ireland has become an important barite producer only recently. Barite is obtained from vein and cavity fill-

Jan 1, 1976

By J. E. Hilliard

AS is well-known, the length per unit volume, Lv, of any lineal feature (such as grain edges in a polycrys-talline specimen) can be estimated from a count of the number of point intersections with a random plane of polish. Specifically:' Lv = 2NA in which NA is the expected number of intersections per unit area of the plane. As with all other measurements in quantitative metallography, the estimation of Lv is subject to a sampling error, the magnitude of which will depend on the number of observations. The analysis is usually performed by counting the number of intersections falling within a closed test figure of known area applied to a succession of different areas on the plane of polish. The test figure can be drawn directly on the screen of a projection microscope or else superimposed on the image of the structure by means of a reticule in a focusing eyepiece of an ordinary microscope. The use of micrographs is very inefficient unless, as in the present study, these are also needed for some other purpose. Consider an analysis in which n applications are made of a test figure within which the expected number of intersections is N. The expected total number of intersections counted is then given by NT = nN If (N) is the standard deviation in N for one application of the figure and if the latter is applied to non-overlapping regions so that the N's are independent in the statistical sense, then the standard deviation in Nt is given by: a(NT) = a(N)vn Eliminating n from Eqs. [2] and [3] we obtain: Thus, k will be a constant for a given specimen and test figure. From Eqs. [ I] and [4] we find As is to be expected, therefore, the fractional error in the estimation of Lv is inversely proportional to the square root of the total number of intersections counted. It is very desirable to have at least a rough estimate of k before starting an analysis, since it will then be possible to decide in advance by use of Eq. [5J how many counts should be made in order to achieve the desired accuracy in Lv. Without such information the investigator, unless lucky, will either do needless (and tedious) work or else obtain a result with too large an error. It is very easy to calculate k for the limiting case of N — 0, i.e., when the test figure is vanishingly small. In this case there is a negligible probability of two or more intersections falling within the figure. There are therefore only two possible outcomes: a count of one with a probability of, say, p and a zero count with a probability of (I-p). Thus and Therefore: We might expect k to depend on N and therefore on the size of the test figure. Such a dependence was observed2 in the analogous case involving the estimation of grain-boundary area per unit volume by a count of the number of intersections of a test circle with traces of the boundaries on the plane of polish. In this case the theoretical value of k at the limit N — 0 was 1.41. It was also predicted that k would display an initial sharp decrease with increasing N. Experimentally, k was observed to decrease to a value of 0.62 at N - 6 and thereafter remain approximately constant. Furthermore, the value of k for N > 6 was found to be insensitive to the form of the structure provided no pronounced anisotropy or grain-size variation was present. In order to determinewhether k would exhibit a similar dependence on N in the estimation of grain-

Jan 1, 1967

By R. J. Corfield

MODERNIZATION of the entire electrical system and improvement of Rotation process efficiency is the twofold goal of the improvement program underway at the Arthur and Magna concentrators of the Utah Copper Div., Kennecott Copper Corp. Copper ore from the Bingham pit goes to these two concentrators where an interlocking program calls for complete electrical modernization and increased flotation process efficiency through additional capacity and flow scheme revisions. Flotation plants at the two mills are essentially duplicates, and while this article deals with the changes at the Arthur mill similiar improvements are being made at the Magna mill.

Jan 3, 1953

By S. E. Haszko

Fused alumina or silica crucibles were used as the containing vessel. X-ray powder photographs were taken with CrKa radiation and the use of Straumanis type Norelco cameras of 114.6 mm diam. Crystallographic data for these compounds are shown in Table I. These results are in agreement with others of this series reported previousiy by Wernick and Geller.l The abnormally large atomic volume of Eu and Yb metal3 is manifested in EuA12 and YbAl2, when one compares them with the compounds reported in Ref. 1. However, the behavior of Yb in the Ni compound is the same as that observed in Ni5Yb having the Cu5Ca structure.4 Thus, it appears that Yb has a valence closer to 3 only in the Ni compounds; i.e.. the 2s and Id electrons are lost to the conduction band. 1,4 Europium in EuAl2, appears to have a valence closer to 2. In previous work.' X-ray patterns of ingots of NdCo2 indicated a multiphase material with faint indication of the presence of a phase having the MgCu2 structure. It was thought that NdCo2 formed peri-tectically from the melt, resulting in a multiphase system when cooled under nonequilibrium conditions. An X-ray pattern of a sample from a melt cooled more slowly than in past work showed that the major phase was NdCo2. The lattice constant, Table 1, is in excellent agreement with the value one can predict from the data of Ref 1. One of the other phases was identified as Co,Nd. The author wishes to thank J. H. Wernick for his guidance in this work, and D. Dorsi for the preparation of these compounds. 'J. H. Wernick and S. Geller: AIME Trans., in press. 'J. H. Wernick and S. E. Haszko: to be published. 'F. H. Spedding and A. II. Daane: Progress in Nuclear Energy, Series 5, Eds.: H. M. Finniston and J. P. Howe, McGraw-Hill Book Co., 1956. 'S. E. Haszko: to be published. 'J. H. Wernick and S. Geller: unpublished work. 6J. 11. Wernick and S. Geller: Acla Cryst., 1959, vol. 12, p. '162. The Influence of Hydrogen on the Lattice Parameters of Ti-Sn Alloys A. Coucoulas and H. Margolin A reinvestigation of the lattice parameters of Ti-Sn alloys by the present authors has revealed consistently higher c and a values than those obtained by Worrier. The difference is most pronounced in the c-parameters which are, therefore, used as a basis of comparison. This discrepancy was not due to air contamination, since precautions were taken to exclude this possibility. Specimens for Debye-Scherrer photograms were prepared by arc-melting 15-g buttons of Bureau of Mines titanium and 99.99 pct Sn, with compositions of 6, 8, 10, and 12 at. pct Sn. These buttons were forged under an oxygen-acetylene torch to 1/8-in. sq rods to produce relatively fine grained material. Scale and some surface were ground off, and the rods, after wrapping in molybdenum and titanium sheet, were vacuum annealed 15 min at 800 °C to remove hydrogen. Heat treatment of one of the samples at 875°C to produce ß and reveal a at the surface showed no surface contamination. Following the vacuum treatment, the specimens were wrapped in molybdenum and annealed for 1week at 800°C under two atmospheres of argon. After water-quenching, the rods were ground so that the thickness tapered to 0.1 mm at the tips. The ground specimens were then recapsuled as previously and reannealed 1 hr at 800°C to remove cold work. The

Jan 1, 1961

By Nagel, Theodore

USE of oxygen in metallurgical operations was investigated by a committee of unusually able engineers more than ten years ago. A record of their work appeared under the title "The Use of Oxygen or Oxygenated Air in Metallurgical and Allied Processes," Serial 2502, Report of Investigations, U. S. Bureau of Mines. Shortly thereafter the A.I.M.E. published "Use of Oxygenated Air in Metallurgical Operations," based on a symposium at the New York meeting, February 1, 924. Quoting from the Bureau of Mines report In view of the many recent developments in oxygen manufacture, and considering the increasing cost and decreasing quality of our raw materials, the Bureau of Mines has taken the matter of the application of oxygen or oxygenated air to the metallurgical centers for consideration and has appointed an advisory committee to study the problem.

Jan 1, 1935

By D. G. Westlake

NUMEROUS hydride habit planes in zirconium, Zircaloy-2, and Zircaloy-4 have been observed by various researchers and have been compiled by Louthan and Angerman.1 While only partial agreement exists on the identification of these habit planes, there is a growing consensus that a tensile stress applied on a polycrystalline rod during slow cooling will cause the hydride platelets to lie perpendicular to the tensile axis. walters2 agrees with Louthan and Angerman who reason that "The particular plane on which precipitation will occur is the plane that will result in the maximum relief of stress by precipitation of the low-density hydride." The experiment described below was initiated to test this hypothesis on a single crystal of zirconium. A single-crystalline tensile specimen of zone-refined zirconium, designated number 13 in a previous study,3 had a square cross section with one pair of parallel faces only 4 deg from the basal plane of the hcp structure. The tensile axis was about 86 deg from the (0001) pole, 14 deg from the (1010) pole, and 16 deg from the (1150) pole. The specimen was charged to 50 ppm H by allowing reaction with the correct amount of hydrogen at 1073°K, homogenizing at this temperature for 2 hr, and cooling in the furnace. Two- surface analysis revealed that hydride platelets had precipitated parallel to the three {1010} prism planes. The specimen was heated to 673°K, in air, for 16 hr to bring the hydrogen back into solid solution, and furnace-cooled to 573°K.* It was then stressed in ten- sion at 1.2 kg per sq mm. (This produced a resolved shear stress of 0.6 kg per sq mm for glide on the prism plane with the highest Schmid factor. A higher stress would have produced significant strain at this temperature because the critical resolved shear stress for prism-plane glide in this crystal was only 1.0 kg per sq mm at ambient temperature.) The poles of the three prism planes were at angles of 14, 46, and 74 deg to the tensile axis so that an applied stress would exert normal stresses on the three planes in the approximate ratios 10:5:1, respectively. As soon as the stress was applied, the sample was furnace-cooled to room temperature. It was ground on wet Sic paper and chemically polished in 50 parts HNO3, 50 parts water, and 7 parts HF before examination. The result of the experiment was negative; i.e., the three (1010) planes were of equal importance as hydride habit planes.* It must be admitted that the ex- periment is not entirely comparable to those performed by walters,2 Louthan,5 and Louthan and Marshall6 on polycrystalline materials. They have found that some critical stress (below the macroscopic yield stress) is required for stress-orienting the hydrides. The applied stress in the present experiment was, by necessity, smaller by an order of magnitude than the critical stresses they report for the various materials. If the critical stress was related to the microstructure, one might postulate that it should be decreased by increasing the degree of perfection of the metal lattice and by increasing the grain size. But the experiment above suggests that, for the extreme case of a zone-refined single crystal of zirconium, the critical stress lies above that which one can apply without introducing gross plastic strain as another variable.

Jan 1, 1967

By W. H. Bassett

Beads of metal frequently appear at the ends of cast-copper wire bars and on the sides of wedge cakes near the top. These are richer in cuprous-oxide than the rest of the casting. A micrographical study of these exudations has been made. It is suggested that the material is forced through the surface while the copper is solidifying. If not eliminated in process of manufacture, it shows on the finished polished sheet copper in patches differing in color from the main body of the sheet. FIGURES 1 to 4 show the copper exudations, at different magnifications, as they appear on the ends of cast wire bars, and on the sides, usually near the top, of wedge cakes. Sometimes the exudations are in fine "drops;" at other times, large masses of the material are found. Microscopic examination of the copper exudation indicates that it is high in oxide and of eutectic proportions. Because of the difficulty of securing a suitable sample, the protuberances have not been analyzed chemically; but the spectroscope shows no indication that there are any more metallic impurities present than in the balance of the copper. The lowest copper plus silver content of the coppers studied for this? paper was 99.914 per cent.; the highest, 99.966 per cent.; so the oxygen content of the whole casting would be well under 0.07 per cent.

Jan 2, 1926

By F. N. Rhines, W. S. Pellini

In many of the otherwise well established alloy phase diagrams the solidus curves (temperatures at which liquid first appears upon melting) have not been located accurately, chiefly because the experimental techniques that have been most popular for determining solidus temperatures have been both cumbersome and subject to large errors. C. E. Homer and H. Plummerl have described a sensitive and at the same time a very simple technique for locating the solidus curves in a number of alloys of tin. Their method consists simply in noting the temperature at which a specimen of the alloy ruptures under the influence of a light bending force. Although this method is not new, it has been little used for this purpose in the past; nevertheless, it appears so attractive in its possibilities of speed, simplicity, and precision that the investigations presently to be described were undertaken to verify its merits. The redetermination of the solidus and eutectic temperatures of the lead-antimony system was employed as a medium of experimentation. New values obtained in this way are believcd to be sufficiently precise to warrant a revision of the currently accepted lead-antimony phase diagram (Fig. I). Determinations of the solidus of the lead-rich lead-antimony alloy series have been published by X. S. Dean2 and by E. E. Schumacher and F. C. Nix. Their points are represented in Fig. I. In their work the solidus was not located at antimony collcentrations greater than 2 per cent; the curve was presumed to meet the eutectic horizontal at an antimony concentration of about 2.5 per cent. In the present studies the solidus has been traced to 3.5 per cent, where the eutectic horizontal is intersected (Table I and Fig. I). Within the range investigated by Dean and by Schumacher and Nix the agreement with their values is good. H. Seltz and B. De Witt,4 on the basis of activity measurements, have calculated that the intersection of the solidus and the eutectic reaction horizontal should lie at 3.86 per cent of antimony. The following determinations of the eutectic temperature have been reported: Roland-Gosselin,5 228°C.; Ewen,6 228OC.; J. E. Stead,7 24g°C.; Campbell,8 228°C.; W. Gontermann,9 245' to 252°C.; R. Loebe,lo 245°C.; E. Heyn and 0. Bauer,ll 245°C.; H. Endo,12 250°C.; R. S. Dean,= 247' to 258°C.; E. Abel, O. Redlich, and J. Adier,13 245°C.; W. Broniewski and L. Sliwowski,14 250' to 252°C.; H. Seltz and B. De Witt,4 25o°C. A temperature of 247°C. appears to have been generally accepted in recent years; it is the value most frequently obtained by the method of cooling curves. Values below 247°C. have usually been obtained by inferior cooling-curve techniques; those above 250°C., by the method of heating

Jan 1, 1943

By W. S. Pellini, F. N. Rhines

In many of the otherwise well established alloy phase diagrams the solidus curves (temperatures at which liquid first appears upon melting) have not been located accurately, chiefly because the experimental techniques that have been most popular for determining solidus temperatures have been both cumbersome and subject to large errors. C. E. Homer and H. Plummerl have described a sensitive and at the same time a very simple technique for locating the solidus curves in a number of alloys of tin. Their method consists simply in noting the temperature at which a specimen of the alloy ruptures under the influence of a light bending force. Although this method is not new, it has been little used for this purpose in the past; nevertheless, it appears so attractive in its possibilities of speed, simplicity, and precision that the investigations presently to be described were undertaken to verify its merits. The redetermination of the solidus and eutectic temperatures of the lead-antimony system was employed as a medium of experimentation. New values obtained in this way are believcd to be sufficiently precise to warrant a revision of the currently accepted lead-antimony phase diagram (Fig. I). Determinations of the solidus of the lead-rich lead-antimony alloy series have been published by X. S. Dean2 and by E. E. Schumacher and F. C. Nix. Their points are represented in Fig. I. In their work the solidus was not located at antimony collcentrations greater than 2 per cent; the curve was presumed to meet the eutectic horizontal at an antimony concentration of about 2.5 per cent. In the present studies the solidus has been traced to 3.5 per cent, where the eutectic horizontal is intersected (Table I and Fig. I). Within the range investigated by Dean and by Schumacher and Nix the agreement with their values is good. H. Seltz and B. De Witt,4 on the basis of activity measurements, have calculated that the intersection of the solidus and the eutectic reaction horizontal should lie at 3.86 per cent of antimony. The following determinations of the eutectic temperature have been reported: Roland-Gosselin,5 228°C.; Ewen,6 228OC.; J. E. Stead,7 24g°C.; Campbell,8 228°C.; W. Gontermann,9 245' to 252°C.; R. Loebe,lo 245°C.; E. Heyn and 0. Bauer,ll 245°C.; H. Endo,12 250°C.; R. S. Dean,= 247' to 258°C.; E. Abel, O. Redlich, and J. Adier,13 245°C.; W. Broniewski and L. Sliwowski,14 250' to 252°C.; H. Seltz and B. De Witt,4 25o°C. A temperature of 247°C. appears to have been generally accepted in recent years; it is the value most frequently obtained by the method of cooling curves. Values below 247°C. have usually been obtained by inferior cooling-curve techniques; those above 250°C., by the method of heating

Jan 1, 1943

By S. A. Falconer

This paper deals with the practical application of the Dutch State Mines cyclone separator for fine-coal cleaning. The more important operating variables are discussed, and results of a number of continuous- scale tests on various fine coals with a 6-in. cyclone separator are given. Descriptions of the Cyanamid Pilot Plant and the 50 tph Cyclone Separator Plant at the Emma Washery in Holland are included.

Jan 7, 1950