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By R. P. Carreker, R. W. Guard

True stress-true strain data are given for nominally pure molybdenum (99.95 pct) over the temperature range -196° to 1540°C (0.027 to 0.63 T/T). Strain rate sensitivity was determined by rate change tests and stress relaxation tests. Inhomogeneous yielding and strain aging effects were observed. The yield stress and tensile strength depend markedly on temperature below 400°C and are insensitive to temperature in the range 400' to 800°C. The ductile to brittle transition range is +25O to -25OC. Strain rate sensitivity and stress relaxation effects are very large near room temperature. THIS report presents data which were obtained as a part of a continuing program designed to document the deformation behavior of nominally pure metals over a wide temperature range.'" This research program is rooted in the conviction that sufficient tensile and creep data of appropriate quality and detail does not exist to provide precise phe-nomenological descriptions of the deformation behavior of pure metals as a function of temperature, strain rate, and grain size. Such knowledge is needed to provide a firm base for alloy design and an experimental framework to which theories of deformation must conform. These data also complement a parallel exploratory program investigating the properties of refractory metals, including molybdenum, and their alloys. Several important reviews and research reports dealing with the tensile properties of molybdenum as a function of temperature have appeared."-lo To a great extent the work to be reported in the present paper parallels that of Bechtold and of Pugh. The authors' results are in general agreement with those of Bechtold and Pugh. The principle differences be- tween the present experiments and those published previously are as follows: 1—Wire specimens prepared from arc cast molybdenum were used in the present experiments, bar specimens were used by others. Pugh used arc cast material while Bechtold's most extensive results" were obtained on powder metallurgy specimens. 2—Several different grain sizes were tested in the present experiments. 3—The testing range was extended to cover from -196°C to 1570°C (0.027 to 0.63 T/Tm). 4—The combination of wire specimens, high speed autographic recording, and a stiff testing machine permitted more detailed study of initial yielding. The principle contribution of the present paper is the demonstration of the relatively consistent mechanical properties of nominally pure arc cast molybdenum specimens of differing metallurgical history. Bechtold and Scotts have shown that arc cast and powder metallurgy molybdenum samples have comparable tensile properties in the range —75" to 200°C when processed to have the same re-crystallized grain size. Material The molybdenum used in this investigation was supplied by the Climax Molybdenum CO. Its metallurgical history is outlined in Table I; the final products were 0,030 in, diam wire specimens annealed at 1100' and 1375°C and 0.060 in. diam wire

Jan 1, 1957

By B. F. Tillson

There is a dearth of information on the economic threat of silicosis. Even the insurance companies and rating bureaus are in a quandary, and the majority of them avoid any action that will stir up an awakened public consciousness of the serious nature of this industrial hazard. Individual claims for $100,000 are now common in silicosis lawsuits. Because of ('hidden costs," in lowered plant efficiency, the total cost of this disease to industry is probably four times its apparent direct cost. The direct costs vary with the labor policies of the employer and with the labor legislation in force. Direct costs may originate in three ways: (1) voluntary assumption by the employer of medical expenses and loss of earning power of stricken employees; (2) state enforcement of industrial disease compensation acts; and (3) awards or settlements after suits in common law. Examples are offered in the last two classifications. In the Rand, South Africa, compensation laws are in effect and in approximately 20 years prior to 1932 about $65,000,000 has been awarded for silicosis and an additional liability of $34,000,000 incurred, or an average of about t5,000,000 per year. During 1932 silicosis compensation on the Rand was about $6,000,000. No figures are available for the direct capital or operating costs for preventive measures there, nor for the additional "hidden costs." It might be reasonable to assume that silicosis has cost the gold-mining industry of South Africa twenty to twenty-five millions of dollars per year. It is estimated that common-law silicosis claims have, in the last few years, aggregated $50,000,000 in New York State alone and have exceeded $300,000,000 in the United States. Attention is called to the involved nature of the insurance situation for industrial diseases in contrast to accidents. The indeterminant, insidious nature of silicosis makes it particularly difficult to predict necessary insurance premiums and reserves. The serious hazard of this disease was not properly appreciated by either insurance companies or industrialists, so sufficient study has not been given its causation, prevention, detection, treatment, and compensation. Therefore legal difficul-

Jan 1, 1934

This fund was established in 1929 for support of research and especially refers to non-ferrous mining and metallurgy. It is administered under the Board by a committee consisting of the President and Secretary and three members selected by the Board. HOWE MEMORIAL LECTURE The Howe Memorial Lecture, in memory of Henry Marion Howe, Past President of the Institute, was authorized in April, 1923, as an annual address to be delivered by invitation under the auspices of the Institute by an individual of recognized and outstanding attainment in the science and practice of iron and steel metallurgy or metallography, chosen by the Board of Directors upon recommendation of the Iron and Steel Division. The following were the Howe lectarers for the years indicated: Albert Sauveur—1924 Bradley Stoughton—1927 John A. Mathews—1925 Henry D. Hibbard—1928 William Campbell—1926 John Howe Hall.—1929 JOINT ACTIVITIES The Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers, and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties. United Engineering Society This is a corporation organized by the American Institute of Mining Engineers, American Society of Mechanical Engineers, and the American lnstitute of Electrical Engineers, to hold the title and administer the property at 29 West 39th St. In 1916, the American Society of Civil Engineers was admitted, and each society now has an equal one-fourth interest in the ownership, occupancy, and administration of the building. . The cost of this property has been over two million dollars. A. I. M. E. representatives are: Arthur S. Dwight, John V. N. Dorr and H. A. Guess. Alfred U. Flinn, Secretary, 29 West 39th St., New York City. Engineering Foundation This is a fund established by the United Engineering Society in 1915 with a gift of $200,000 from Ambrose Swasey. Subsequent gifts had increased the fund to about $620,000 on March 1, 1929. The income of the fund is used to further research in science and engineering and to advance the profession of engineering and the good of mankind. A research project in alloys of iron is being conducted in

Jan 1, 1929

By Nicholas J. Grant, Robert F. Wilde

TAYLOR and Floyd's"" work in establishing phase diagrams based on the elements Ni-Cr-Ti-A1 has led to an understanding of the precipitation hardening mechanism in alloys based on these elements. Nordheim and Grant4 concluded that in simple alloys, and where the aluminum to titanium atomic ratio was such that less than three out of five aluminum atoms were replaced by titanium, the precipitate on aging is the face-centered-cubic Ni 3A 1 phase, called They further found that increasing amounts of hexagonal ? phase, Ni3Ti, precipitated from these alloys when the titanium content exceeded the solid solubility of both matrix and Ni3A1. For alloys of Ni-Cr-Ti-Al, in which the titanium and aluminum contents each ranged from 0 to 4 wt pct, the titanium-rich was superior for strengthening to either pure ?' or 7. It was also noted that the combined titanium plus aluminum content (atomic pct) was a direct measure of the high temperature strength and overaging temperatures for these alloys.4 The present investigation was undertaken to extend existing data on precipitation hardening in the more complex commercial alloys containing higher titanium plus aluminum, and with significant quantities of cobalt, molybdenum, and carbon. Experimental Procedure Reforging of As-Received Bar Stock—The alloys were received as ground, forged bar stock. Chemical analyses and the as-received bar diameters are shown in Table I along with the ASTM grain size after the various treatments. All stock except the Waspaloy was reforged to % in. diam to gain material and to facilitate machining of stress-rupture specimens. Forging was carried out at 2100°F, and discontinued when the bar temperature fell to 1800°F. Heat Treatments—For experixental simplicity it was desirable to heat treat all of the alloys at, the

Jan 1, 1958

By B. F. Tillson, C. M. Haight

I. General Remarks..........................723 1. Location............................723 2. Characteristics of the Orebody..................725 (a) Mineralogical (b) Shape, Strike, Dip, Size, Etc. (1) Ore (2) Country Rock 3. Historical Sketch........................725 11. Mining Method..........................726 1. Outline of Methods Now in Operation............... 726 (a) Stopes (b) Fill . (c) Pillars (d) Slices (e) Transportation (f) Miscellaneous 111. Mining Operations........................727 1. Shaft..............................727 (a) Sinking (b) Dimensions and Equipment, Sketches (1) Size, Inclination. Direction, Etc. (2) Timbering (3) Stations (4) Track (5) Hoisting Equipment (a) Skips (b) Engines and Ropes (c) Idlers (d) Man Cars (6) Loading Pockets (a) Operating Figures (7) Headframe

Jan 1, 1918

By S. Leber, R. F. Hehemann

This investigation describes the kinetics of alloying in a (Cb-15 wt pct W. 5 wt pct Mo, 1 wt pct Zr) powder-metallurgy alloy. The degree of homogeneity obtained in hydrostatic ally pressed and vacuum-sintered samples is described by composition distributions resulting from analysis of X-ray dvfraction line profiles. Sintering variables and degvee of powder dispersion were evaluated. The utility of single-value parameters obtained from composition distributions is disaissed. The spatial distribution of composition, as revealed by anodically tinted metallographic sarrzples, was used to provide diffision models based on a concentric-sphere geometry. Diffusion equations developed from these models were found to be in general agreement with experimental results. The powder-metallurgy method for the production of refractory metal alloys has the ability to produce an inherently fine-grained, fabricable structure. The more general use of this method is inhibited, in part, by the presumed difficulty in obtaining homogeneity on a microscale. The degree of homogeneity therefore is an important, but usually neglected, variable in specifying the quality of a powder-metallurgy alloy. Convenient techniques for measuring the degree of homogeneity are now available,' and have been used to develop a model describing the process of alloying in a simple binary mixture.' In this investigation, the process of alloy formation has been studied in a more complex system. PROCEDURE The columbium-based F-48 mixture was prepared from the constituent powders shown in Table I. The particle sizes tabulated were provided by the vendors of the individual powders. Standard laboratory techniques utilizing a jar mill were employed for blending. The blended powders were hydro-pressed into 1-in. diam rods which were then sliced into thin discs for vacuum sintering. All samples were given a preliminary treatment at 1700°C for 2 hr. Varying degrees of homogeneity were obtained using additional treatments at higher temperatures. The degree of homogeneity obtained by a specific sintering treatment was evaluated metallographi-cally using the anodic-tinting technique described by olff,' and quantitatively by the analysis of X-ray diffraction line profiles using the X-ray diffraction technique developed by udman.' The diffraction technique is strictly valid only for binary systems. However, the relatively small difference between the lattice parameters of tungsten and molvbdenum when compared with columbium permitted the treatment of the complex composition of F-48 as a (W, Mo)-Cb pseudobinary. Calculations were weighted in accord with the W-Mo ratio in the F-48 composition. The contribution of the 1 pct Zr was ignored since it could not even be detected in the blended powder. Two factors are required to convert an X-ray line profile into a composition distribution. The variation of these factors with composition is shown in Fig. 1. Curve A was used to convert angular posi-

Jan 1, 1964

By A. S. Grove, C. T. Sah, E. H. Snow, B. E. Deal

A summary of- several recent investigations in to the properties of the metal-oxide-silicon system is presented. A major portion of these studies makes use of the MOS capacitance-z)oltage method of' analysis. The particular areas of investigation which are reported include: 1) a general survey of the electvical properties of thermally oxidized silicon surjbccs; 2) a study of ion migration through silicon dioxide films ; 3) measurements of electron and hole mobilities in surface inversion layers; 4) a study of impurity redistribution due to thermal o.ridatiotz; and 5) measurements of the rates of oxidation oj-heavily doper7. silicon. THE importance of the metal-oxide-semiconductor (MOS) system in the semiconductor industry is well-known. In addition to its importance in the "planar" device technology,' the MOS structure is now also used in the fabrication of active solid-state devices. Consequently, extensive efforts have been made recently to obtain a better understanding of the characteristics of this system. A summary of some studies of the MOS system conducted in our laboratories during the past year is presented. For the most part these studies used silicon as the semiconductor, along with silicon dioxide and aluminum as the other two components of the system. Since the MOS capacitance-voltage method of analysis was used extensively in these studies, we will first briefly describe its nature and consider some of the possible causes of deviation of experimental observations from the simple theory. We will then outline the various related areas of investigation carried out in our laboratories and will briefly indicate some of the results. It should be noted that the purpose of this paper is merely to provide a brief summary of MOS studies. More detailed discussions of the various areas of investigation are given in the references cited. PRINCIPLES OF THE MOS C-V METHOD OF ANALYSIS' A sketch of the MOS structure is shown in the upper portion of Fig. 1. In this case the insulating film is Si02 and the semiconductor p-type silicon. If a large negative bias is applied to the metal field plate, holes are attracted to the silicon surface. The silicon then behaves much like a metal and the capacitance measured is that of the oxide layer alone, Co. If a small positive bias is applied to the aluminum, holes are repelled and a region depleted of majority carriers is formed at the silicon surface. This depletion I-egion adds to the width of the dielectric and the measured capacitance begins to drop. With increasing positive bias, the width of the electrical depletion region increases. At some large positive bias an inzevsion regiotr is formed at the surface and additional charges induced in the silicon appear in the form of electrons in this narrow inversion region. Thus the depletion-region width approaches a maximum value and, consequently, the capacitance reaches a minimum value and then either levels off or rises again depending on the measurement frequency and the rate of equilibration of the minority carriers in the inversion layer.3 Band diagrams, along with the corresponding charge distributions, are shown in Fig. 1 for the above bias conditions. If minority carriers cannot accumulate at the surface to form an inversion region, the depletion-region width continues to increase with increased positive bias and the capacitance drops toward zero as in a reverse biased p-n junction. The effect of a work-function difference $hs between the metal and the silicon, and of surface charges per unit area Qss located at the oxide-silicon interface, is simply to attract charges in the silicon much like the applied bias. It can be shown that this results in a parallel shift of the capacitance-voltage characteristic along the voltage axis by an amount corresponding to AV = -$bIs + Qss/Co. Theoretical curves have been calculated4 giving the capacitance of the MOS structure C normalized to the oxide capacitance Co vs the quantity VG here VG is the voltage applied to the metal field plate. In Fig. 2 such calculations are shown as points for a particular oxide thickness and bulk impurity concentration for a p-type semiconductor. (For an n-type semiconductor the curves would be mirror images of these.) All three cases, i.e., low frequency. high frequency, and depletion, are indicated. Also shown in the figure are recorder tracings of the characteristics of actual devices. These characteristics have been shifted along the voltage axis to compensate the effect of surface charges and work-function difference. It is evident that agreement between experiment and theory is good. The nature of this shift along the voltage axis is

Jan 1, 1965

By Eugene McAuliffe

IT is not possible to include in this paper, limited as it is in scope, the many diverse steps toward the reduction of mine accidents that are taken in the mines that produce the nation's coal. Every coal-producing state has enacted laws covering proper mining practices, and the major portion of these are directly related to the safety of the mine employees. The United States Bureau of Mines, the American Institute of Mining and Metallurgical Engineers, The American Mining Congress, a number of national, regional and state organizations, as well as the coal technical press, have covered time and time again all of the "do" and "don't" phases of mine operation that bear on the important question of mine and employee safety. Within the past 15 years The Union Pacific Coal Co. has attempted to put into practice in its mines in southern Wyoming these many good recommendations, finding some value in all, and yet, to secure substantial results, the management found it necessary to resort in the end to what might be referred to as "extra-territorial" methods. It is the writer's purpose to show in this paper that marked and even extraordinary betterment can be brought about when employer and employee work together with due sincerity. In presenting our own experi-ence, one that has been duplicated in so far as results are concerned on numerous other properties, no theory of perfection of management exists; on the other hand, our organization feels that as long as our record of accidents remains as shown by even our latest and best performance we still have far to go. Safety work in some form has been carried on in and about the mining properties of The Union Pacific Coal Co. since the first mine was opened at the now long-abandoned town of Carbon, Wyo., in 1868. On June 30, 1903, an explosion and subsequent mine fire occurred in mine No. 1 at Hanna, taking 169 lives, and a second explosion occurred in tile same mine on March 28, 1908, in which 59 additional lives were lost. Looking back with impartiality on the causes leading up to these two unfortunate disasters, we can only conclude that shooting from the solid, the absence of adequate ventilation, rock dusting, the use of water at the face to allay

Jan 1, 1938

J. E. JOHNSON, JR., New York, N. Y. (communication to the Secretary*).-The discussion of Mr. Henrich's paper took place at a meeting from which I had the misfortune to be absent, and has just come to my attention. I do not wish to let the subject pass without contributing to it a little information which has come into my possession. In 1912, I published a brief note in the Transactions on The Effect of Alumina in Blast-Furnace Slags, giving in tabular form three typical slags used in iron blast-furnace practice, one of them the high alumina slag of, which Professor Richards speaks. That table is reproduced herewith. TABLE 1.-Composition of Slays. 1 3 3 4 5 6 7 CaO by Neutral Ratio Ratio Ratio Al2z03, SiO2, Differ- Substan- Cat Ca0 a A1203 Ratio Per Per ence, ces, CaO Cent. Cent. Per Per Al2O3 + Sioz Sit: SiO2 Cecil_ Cent. Virginia practice 6.5 36.0 54.0 3.5 1.27 1.6S 1.50 Lake-ore practice 13.5 33.0 50.0 3.5 1.08 1.92 1.51 Special experiment... 36.0 24.7 36.8 3.5 0.59 2.90 1.44 It supplies what seems to me convincing evidence that, for the purposes of the iron blast furnace, alumina can be regarded only as a neutral substance, dissolving in the slag and materially altering its viscosity, but not affecting its chemical activity. In subsequent experience with charcoal furnaces, I found the same rule to hold; that the chemical effect of alumina could be disregarded, providing the ratio of the lime and magnesia to the silica were kept constant. This is exactly the experience which Messrs. Dwight and Mathewson had in copper- and' lead-smelting furnaces. I have never seen any evidence or argument adequate to support the contention of Professor Richards-that the alumina acted as a base in the charcoal iron furnace and as an acid in the coke furnace, and that the function of alumina in iron-furnace slags is inherently different from that in copper- and lead-furnace slags-and I am compelled to differ absolutely with his conclusions in that respect.

Jan 9, 1917

By A. B. Calhoun

These mines, which belong to the Burma Corporation, Ltd., formerly a London company now incorporated in Rangoon, Burma, are situated in the semi-independent state of Tawng-Peng, one of the small divisions comprising the northern Shan states and erroneously known as part of Upper Burma. Bawdwin is approximately 23' 6' N. latitude and 97" 20' E. longitude, 450 miles north of Rangoon, 169 miles northcast of Mandalay and 50 miles south and west of the Province of Yunnan, China (see Fig. 1). Although the mines were worked by the Chinese during the Ming Dynasty, 1412 A. D., the most extensive operations took place between 1796 and 1851, when the mines contributed largely to the silver market of China. During the reign of Tung Chik, 1868 A. D., they were abandoned partly because of the Mohammedan rebellion in Yunnan, which made life and property insecure, but largely because of the difficulty of operating the mines on account of water and poor ventilation. Since that time practically nothing was done, although the Burmese kings are said to have made several sporadic attempts to work the mines, until 1891 when Europeans were attracted by the great slag dumps (assaying about 40 per cent. lead) which the Chinese had left after extracting the silver. After a railroad and smelter had been built and 200,000 to 300,000 tons of slag smelted for lead, exploration work was started and old workings cleaned out in order to locate the remnants of the orebody that it was supposed the Chinese had left. After two years of most discouraging work, the remains of a large orebody was discovered by the Dead Chinaman Tunnel or what is the 171-ft., or No. 2 level adit. From then on the development was rapid and today the Chinaman is considered one of

Jan 1, 1923

By A. B. Calhoun

These mines, which belong to the Burma Corporation, Ltd., formerly a London company now incorporated in Rangoon, Burma, are situated in the semi-independent state of Tawng-Peng, one of the small divisions comprising the northern Shan states and erroneously known as part of Upper Burma. Bawdwin is approximately 23' 6' N. latitude and 97" 20' E. longitude, 450 miles north of Rangoon, 169 miles northcast of Mandalay and 50 miles south and west of the Province of Yunnan, China (see Fig. 1). Although the mines were worked by the Chinese during the Ming Dynasty, 1412 A. D., the most extensive operations took place between 1796 and 1851, when the mines contributed largely to the silver market of China. During the reign of Tung Chik, 1868 A. D., they were abandoned partly because of the Mohammedan rebellion in Yunnan, which made life and property insecure, but largely because of the difficulty of operating the mines on account of water and poor ventilation. Since that time practically nothing was done, although the Burmese kings are said to have made several sporadic attempts to work the mines, until 1891 when Europeans were attracted by the great slag dumps (assaying about 40 per cent. lead) which the Chinese had left after extracting the silver. After a railroad and smelter had been built and 200,000 to 300,000 tons of slag smelted for lead, exploration work was started and old workings cleaned out in order to locate the remnants of the orebody that it was supposed the Chinese had left. After two years of most discouraging work, the remains of a large orebody was discovered by the Dead Chinaman Tunnel or what is the 171-ft., or No. 2 level adit. From then on the development was rapid and today the Chinaman is considered one of

Jan 1, 1923

The following is an extract of the Engineers' licensing law recently passed by the Colorado legislature; it went into force July 10. On the board of examiners are representatives of the four national societies. R. J. Grant, of Denver, represents the American Institute of Mining and Metallurgical Engineers; H. I. Reid, of Colorado Springs, the. American Society of Civil Engineers; H. S. Sands, of Denver, the American Institute of Electrical Engineers; and Frank E. Shepard, of Denver, the American Society of Mechanical Engineering. Within sixty clays after the taking effect of this act the Governor of the state shall appoint a State Board of Engineer Examiners, to be composed of five members, who shall be legal residents of the state of Colorado and who shall have been engaged in the practice of engineering for at least ten years. Upon the expiration of the term of any members other than the state engineer the governor shall appoint their successors for a term of four years, from a list of five nominees elected by the licensed engineers acting in a general assembly called together for this purpose by the president of the board. Such assembly shall be held in the month of January next preceding the expiration of the terms of any members. The Board of Examiners shall adopt all necessary rules, regulations and by-laws to govern its proceedings, not inconsistent with this act or the laws of the state or of the United States.

Jan 8, 1919

By John S. Brown

AT opposite ends of a mineralized belt of northeast-southwest trend, and ten miles apart, are the Edwards and Balmat zinc minas, in St. Lawrence County, New York, west of the Adirondacks. The principal town is Gouverneur, fifteen miles west of Edwards, eight miles northwest of Balmat, and the area is often referred to as the Gouverneur district. (See Fig. 1.) At various times the district has been noted for its hematite mines, pyrite mines, and marble quarries, all now abandoned. At present, in addition to zinc, it is the country's largest source of industrial talc. A short distance to the east important magnetite mines are operating. Geologically the district lies at the southern margin of the Canadian shield, where this great expanse of Pre-Cambrian igneous and metamorphic rocks merges into the foothills of the Adirondacks. The rock formations in approximate order of areal extent and importance are as follows:

Jan 1, 1947

By Rafael Errazuriz

About eighty miles north of the city of Antofagasta, Chile, located just below the Tropic of Capricorn, there spreads a wide desert area where copper oxide outcrops can be seen with the naked eye. Numerous old mining works and dump heaps with the green of atacamite and chrisocolla shining in the blazing sun, attest to the work done by miners in the beginning of this century. The dry desert air preserves the footstep marks, paths and trails of old cartwheels from years back. The mining area known as Michilla and Panizos Blancos, is located on the high plateau at 3000 ft above sea level. Around 1920 a Bleichert ropeway was built, which carried ores from the best known mine to a wharf at the Michilla bay. High grade silicious ores were shipped to the Gatico Smelter further north or to smelters in the United States or Japan.

Jan 8, 1973

By N. H. Darton

In the coastal plain region of the middle Atlantic slope there are no large supplies of potable surface-waters. The great rivers by which the region is intersected are tidal estuaries, and the water of their local branches is often of bad quality. The cities situated at intervals along the western margin of the region obtain a plentiful supply of excellent water from the rivers above the tidal estuaries, but out on the coastal plain surface-waters are mainly used. A few artesian wells have been sunk which afford abundant water, but their number is at present very limited. Norfolk, Newport News, and the many smaller places use surface-waters, and all over the region there is great need for purer and more abundant supplies. During the past five years I have been engaged in a study of the geology of the coastal plain for the U. S. Geological Survey, and have given special attention to the question of subterranean waters. In this communication I shall present a brief review of the geological conditions under which such waters occur in this region, and give an account of the wells which have been bored. Unfortunately the number of well-records is small, and some of the most important questions of subterranean geology are as yet far from settled. It is hoped that this paper may lead to further borings, especially as the cost of artesian wells has been much reduced by the introduction of new machinery and methods, and is now quite within the reach of the average community. In New Jersey there are many wells, and the water-bearing horizons are so definitely determined that they may almost everywhere be predicted with certainty. In Maryland and Virginia the data are less definite, but there is excellent evidence of a wide distribution of water at moderate depths.

Jan 1, 1895

By H. L. Gilbert, H. A. Johansen, R. G. Nelson

High purity electrolytic chromium plate has been hydrogen-reduced and arc-melted under inert atmosphere to give sound ingots. These ingots may be hot forged to break the as-cast structure and then worked at 500°C to finished form. An intermediate and final high temperature anneal gives best ductility and grain refinement. HE increasing interest in refractory metals for I use in high temperature gas turbines, jets, and rockets has led to great efforts in exploiting the fifth and sixth groups of transition elements. Much of the interest has centered upon production of metals that can be worked and fabricated by normal means to produce various engine parts or components having the high temperature characteristics of oxidation resistance and high creep strength required for such uses. If these pure elements do not exhibit all of the desired characteristics, it may be possible to obtain a high purity alloy that will. Since, in all cases, development of these transition elements has depended to a large extent upon removal of oxygen and nitrogen as a means for producing ductile metal, the hypothesis has been accepted that oxygen is the normal embrittling material in a high grade electrolytic chromium metal. Various methods have been employed in an effort to remove this oxygen by direct or indirect attack.' Many workers have endeavored to produce pure chromium through reduction of the oxide by carbon or active metals, while others have recommended fusion electrolysis of chromium salts or reduction of these salts by active metals, such as sodium or calcium. Hydrogen reduction of the oxide or chloride and thermal dissociation of the iodide have been reported to give high purity metal. Experimental Work The U. S. Bureau of Mines, Northwest Electro-development Laboratory, has systematically re-examined the more promising methods and developed two which produce metal having ductility at temperatures lower than heretofore described. It has been found' that oxide-free chromium chlorides in a NaCl-KCl carrier salt may be mag- nesium-reduced and the byproduct salts distilled off in vacuo to give a high purity chromium sponge. Fusion analysis conducted under the supervision of W. W. Horton of Knolls Atomic Power Laboratory showed the oxygen and nitrogen both to be below 10 parts per million on a selected sample. A small amount of carbon is carried over in the final metal from the chlorination and reduction steps which are carried out in graphite crucibles. This trace of carbon is not detrimental to hot ductility. A more practical method for producing ductile metal is through hydrogen reduction of high purity electrolytic chromium. Normal electrolytic chromium will, if "developed" for a few minutes at 1100°C in high vacuum, be found by the method of Adcock:; to contain about 1 pct chromium sesquioxide (Cr2O3). This small amount of oxygen may be effectively reduced by hydrogen.2, 4 The method employed was to crush electrolytic chromium plate in a gyratory crusher to pass 60-mesh; finer crushing appears to offer no advantage. A nitric acid leach removed the iron picked up during crushing. The leached powder was rinsed until neutral with distilled water and vacuum-dried.

Jan 1, 1954

FROM north to south activity is picking up through- out the Labrador Trough-already shown to be one of the world's great iron ore provinces. Center of current activity and interest lies in the mid-southern part of the trough as drills, equipment, and . . . money start to pour into the area near Mt. Wright and Wabush Lake. First major announcement in the area came early this spring when J&L and CCI outlined an estimated billion-ton deposit for "future" operations. Later impetus came from rumored railway for US Steel's Quebec Cartier projects in the Mt. Reed area slightly to the south. As this issue went to press US Steel's request for bids on railway and hydroelectric construction, plus IOCC's decision to step up the time- table on its program in the Wabush Lake area east of Mt. Wright, triggered a flurry of other announcements involving many of the top U. S. and Canadian iron ore firms. Do not look for most of these place names in the average atlas . . . they aren't there yet, but they soon will be.

Jan 6, 1958

By F. W. Bremmer

The experiments described in this paper constitute the preliminary work of an investigation outlined to determine the combined effects of steam and temperature on the endurance properties of certain steels. Essentially of a fundamental nature, it was found necessary, in order to make the investigation comprehensive, to test materials treated to give a wide range of properties. The work reported deals chiefly with nickel steel with one series of tests including nitriding steel. Such a study involves numerous variables, and requires an endurance-testing machine of rather special design. Testing Machines The testing machines used were designed by C. E. Weaver;l they are a modification of the White-Souther and McAdam types. Each was driven directly by an individual 1/2-hp. 115-volt direct-current motor, running at a speed of 2200 r.p.m. Fig. 1 shows the assembly drawing and Fig. 2, a photograph of one of the machines. Specimen B is held by the rotating specimen holder A inside the steam box F, which is closed at the top by a tight-fitting, elliptical cover G. The load is applied to the specimen through the rod D and bearing C. E is an oil pipe leading fromthe lubrication system to the bearing C. The steam, which comes from the power house, is admitted through an inlet (not shown in Fig. 1) at the side of the box, the drain being at the bottom. Steam packings were placed around the rod D and the rotating shaft at H, from which the water was drained by means of a vacuum, which usually showed a gage reading of about 10 in. The temperature was measured by a mercury thermometer, and the pressure by a steam gage. Method of Applying Load After the motor has been started and the specimen as a consequence put in rotation, the load is applied by placing the foot pedal A (Fig. 2) in contact with electromagnet B, the winding of which is connected electrically in series with the motor. This operation releases the support under the weights that constitute the load. By this means the load

Jan 1, 1930

By M. H. Gidel, D. C. Bard

These notes are based on the megascopic study of a suite of 2,400 specimens of minerals and ores from the Butte mines, combined with field observations at intervals over a period of several years. The estimate of average vein composition is based on field acquaintance with the veins. It is probably correct in its broader proportions, and should be of use for comparison. Chemical and Mineral Composition of Unoxidized Vein Matter. Per Cent. Oxygen,......48.00—Quartz, rhodonite, rhodochrosite, sericite, kaolinite, barite, calcite, and hübnerite. Silicon,...... 36.O0—Quartz, rhodonite, sericite, kaolinite, and willemite (very rare). Sulphur,.....5.0—Sulphides of iron, zinc, copper, lead, and sulphates of barium and rarely calcium. Iron,.......5.00—Ferric sulphides (pyrite, bornite, chalcopyrite), also in sphalerite, tetrahedrite, and rarely hematite and siderite. Manganese,.... 2.00—Rhodonite, rhodochrosite, and hübnerite. Zinc,.......1.00—Sphalerite, very rare wurtzite and willemite, and tetrahedrite and tennantite. Carbon,......0.50—Rhodochrosite and calcite. Capper,......0.75—Cuprous ( + ) and cupric (—) sulphides. Aluminum,.... 0.50—Sericite and kaolinite. Hydrogen,.... 0.50—Water, sericite, and kaolinite. Potassium,.....0.20—hicite. Lead,....... 0.20—Galena. Arsenic,......0.10—Tennantite and enargite. Barium,......0.10—Barite. Calcium,.....0.10—Fluorite, calcite, and rare gypsum. Antimony,.... 0.02—Tetrahedrite, famatinite, and silver sulphantimonites. Fluorine,.....0.05—Fluorite. Silver,.....1 —Argentite, and sulphantimonites. Tungsten,.... —Hübnerite. Phosphorus, • —Wavellite. Bismuth,' .... 0.05—Sulphide (?) Tellurium,... 1 —Telluride (?) Selenium,.... —Selenide (?) Cadmium,.... —Sulphide (?) Gold,..... —Native and telluride (?)

Jan 1, 1914

By John R. Keith

Lead and zinc contents of elm, maple, and oak trees and of soils in which the trees grew were determined in samples from the Upper Mississippi Valley mining district, and from an area outside but contiguous to the district. The lead and zinc analyses of plant materials served to differentiate the mineralized and nonminer-alized areas. Stems contained about two times as much lead and about two to five times as much zinc as did leaves taken from the same stems. Lead and zinc analyses of all soil horizons could be used to differentiate between the two areas. Soils at most sample sites in the mineralized district seemed to be more reliable than plants for geochemical prospecting and are a more practical sampling medium. Soil samples from areas with thick loess cover, however, failed to indicate the presence of mineralized bodies whereas tree samples from the same sites contained anomalous amounts of lead and zinc. It is suggested that in areas of thick loess cover, plant samples could be used in prospecting for lead and zinc. The important part that plants play in the cycling of elements through the soil horizons is well-known. The concentration of elements in the upper soil horizons by the action of plants has been called the Goldschmidt enrichment principle.' The fact that plant species vary greatly in their ability to concentrate particular elements in their tissues is also well-known.' Agricultural literature has dealt extensively with relationships of the major nutritive elements in soils and plants3 The extent, however, to which plant actions cycle the minor nutritive and the nonmetabolic elements in the soil has not been adequately investigated. Lead is non-nutritive and toxic to plants, whereas zinc is a micronutrient in low, but toxic in high, concentrations.4 This report presents the results of a biogeochemical study concerned with the amounts of lead and zinc in some plants and soils that occurred both within and adjacent to the Upper Mississippi Valley lead-zinc district. Field work for this study was done in the summers of 1961 and 1962. SAMPLE TARGETS AND CHEMICAL ANALYSES Geologic and physiographic descriptions of' the district have been made by Heyl 5 and several other authors in a series of U.S. Geological Survey (USGS) reports and quadrangle maps.6-I Sedimentary rocks, mostly dolomite, limestone, shale, and sandstone, of Cambrian, Ordovician, and Silurian age predominate in the area. Mineral deposits are of the vein and cavity-fill type; the principal ore minerals are galena and sphalerite. Vegetation of the area was characterized by Curtis1 6 as southern hardwood forest interspersed with patches of oak savanna and prairie. Plant genera typical of the eastern United States Temperate Zone, including ash, cherry, dogwood, elm, hackberry, hickory, maple, oak, and other woody and herbaceous genera, are present. The natural vegetation has been greatly modified by agricultural, logging, and mining operations. The species of the original flora are present, but not in their former relative abundance. Soils of this district belong, for the most part, to the Brunizem and Gray-Brown Podzolic great soil groups. The Brunizems are the soils developed under prairie vegetation.'' The Gray-Brown Podzolics are the soils developed under deciduous forests,18 They are derived from both bedrock and from loess parent materials, and

Jan 1, 1970