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By E. H. Dix

The success of the Charpy impact test in the steel industry has led those interested in aluminum alloys to investigate the possible application of this test to aluminum and its alloys. In this paper are set forth the results of a few preliminary tests made at the Lynite Laboratories of the Aluminum Manufactures, Inc. In order to study more thoroughly the significance of the Charpy test, slow-bending tests have been made duplicating the arrangement of the impact machine. Tests have been made on both notched and unnotched specimens of a series of copper-aluminum alloys. Apparatus The standard American-made Charpy impact machine delivering a blow of over 200 ft.-lb. was much too large to test aluminum-alloy specimens of the same type used for steel, so that it was necessary either to adopt a larger specimen or to have a special light-weight hammer made. Since there is no known relation between specimens of different sixes, even though geometrically similar, it was decided to adhere to the 10 by 10 mm. specimen. Accordingly, Sauveur and Boylston, the American makers of the machine, were asked to construct a special light-weight pendulum adapted to their standard machine, this pendulum to have one-tenth the capacity of the standard. The writer wishes here to acknowledge his indebtedness to Mr. H. M. Boylston for the personal interest and care exercised in constructing this pendulum. The machine with the light-weight hammer in place is shown in Fig. I. It is mounted on a concrete foundation with the concrete covering the flange on the base of the machine. Vibration is further prevented by four 5/8-in. (15.8 mm.) foundation bolts. The large standard hammer shown against the wall was also used for some of the unnotched bars that required more than 20 ft.-lb. to rupture. When the light-weight hammer was received, it was carefully cali-

Jan 1, 1921

By R. M. Brick, Arthur Phillips

The normal method of preparing metallic alloys for commercial use involves the preparation of a melt containing the given components in the chosen proportions and allowing the homogeneous liquid mass to solidify in a mold of the desired form. The solidification is frequently accompanied by a segregation of the alloying elements in different parts of the casting. When the segregation is occasioned primarily by marked differences in density of the solid and liquid phases, it is termed "gravity" segregation. When the segregation conforms to a selective freezing in harmony with the teachings of the equilibrium diagram of the alloy system—i.e., the lower melting phases are concentrated in the regions of the casting last to freeze—it is often referred to as "normal" segregation. However, in many cases the lower-melting part of the system is concentrated in the parts of the casting first to freeze and the result in this case is termed "inverse" segregation. To complete the terminology of the subject, normal segregation in a single phase is usually called "coring" and the word will be used in that sense in this paper. Inverse segregation, particularly when the liquid phase is exuded or sweated out on the surface of the casting, is sometimes called "liquation." Unfortunately, some ambiguity has arisen from the use of this term and it is perhaps advisable to confine its use to the dictionary definition; namely, "The separation of two phases by heat sufficient to melt one but not the other." The gravity and normal types of segregation are both well understood and to some extent, are controllable by taking advantage of the most favorable cooling rate for a given casting condition. Inverse segregation has received considerable attention from several investigators but none of the theories offered seem to account in a convincing way for the many examples of this type. The observations made in the present work on segregation in single crystals, and in some other castings, tend to support one theory of the mechanism of inverse segregation and definitely to

Jan 1, 1937

By John A. Mathews

It is twenty years since the writer made his first molybdenum steels and others were making them commercially five years earlier but the prevailing opinion seems to be that molybdenum steels are new; from time to time the daily press speaks of important discoveries in Europe and intimates that American steel makers have much to learn in regard to alloy steels. The earlier experiments were largely confined to the use of relatively high percentages of molybdenum in tool steels and permanent magnet steels. Recent developments deal with the types of alloy structural steels used for airplane, automobile, and other engineering requirements; in these, the molybdenum content is usually less than 1 per cent. The earlier types generally have been unsuccessful commercially, but the newer types of steels are becoming of increasing importance. The war showed our dependence on foreign sources for alloying metals; molybdenum alone is widely distributed in the United States and seemingly abundant. Many deposits are not now of commercial interest, owing to location and relatively small amount of ore available, but other deposits are being developed and a stable source of supply seems well assured. In tool and magnet steels, it was early found that 1 part of molybdenum was equivalent to from 2 to 2.5 parts of tungsten. The permanent magnet steels investigated by Madame Curie,' in 1898, contained from 3.36 to 4.05 per cent. molybdenum; in 1902, Dr. E. L. French and the writer thoroughly tested steels containing from 2.0 to 4.0 per cent. These steels gave satisfactory tests for permanence, but were low in residual density and much more sensitive to hardening than the corresponding tungsten products. We discontinued work with them, therefore, and have no advice that such steels have been used commercially here or abroad. Prior to the development of the Taylor-White process and the modern high-speed steels, air-hardening steels were in general use. These were

Jan 1, 1922

By John A. Mathews

It is twenty years since the writer made his first molybdenum steels and others were making them commercially five years earlier but the prevailing opinion seems to be that molybdenum steels are new; from time to time the daily press speaks of important discoveries in Europe and intimates that American steel makers have much to learn in regard to alloy steels. The earlier experiments were largely confined to the use of relatively high percentages of molybdenum in tool steels and permanent magnet steels. Recent developments deal with the types of alloy structural steels used for airplane, automobile, and other engineering requirements; in these, the molybdenum content is usually less than 1 per cent. The earlier types generally have been unsuccessful commercially, but the newer types of steels are becoming of increasing importance. The war showed our dependence on foreign sources for alloying metals; molybdenum alone is widely distributed in the United States and seemingly abundant. Many deposits are not now of commercial interest, owing to location and relatively small amount of ore available, but other deposits are being developed and a stable source of supply seems well assured. In tool and magnet steels, it was early found that 1 part of molybdenum was equivalent to from 2 to 2.5 parts of tungsten. The permanent magnet steels investigated by Madame Curie,' in 1898, contained from 3.36 to 4.05 per cent. molybdenum; in 1902, Dr. E. L. French and the writer thoroughly tested steels containing from 2.0 to 4.0 per cent. These steels gave satisfactory tests for permanence, but were low in residual density and much more sensitive to hardening than the corresponding tungsten products. We discontinued work with them, therefore, and have no advice that such steels have been used commercially here or abroad. Prior to the development of the Taylor-White process and the modern high-speed steels, air-hardening steels were in general use. These were

Jan 1, 1922

By D. C. Seidel, M. C. Fuerstenau, R. J. Roman

The role of surface charge in soluble salt flotation, which was developed in Part I, is extended to relate the theory to the specific phenomena of KCI-NaC1 separations. Temperature-collector solubility relationships, metal ion activation, and particle size effects are discussed. The initial paper in this series developed and presented the hypothesis that one of the mechanisms of soluble salt flotation may involve electrical attraction between the collector and mineral surface. This hypothesis was developed from a combination of experimental data and free energy calculations, and details of the logic are presented in this first paper.* The studies have indicated that KC1 has a positive surface charge and NaCl a negative charge. KC1 can therefore be floated with sulfonate ion (RSO;) or with an aqueous polar species such as the aqueous amine chloride, RNH3C1(,,). The chloride end of the RNH3C1(,,) molecular dipole is probably negative and will be attracted to the positive surface of the KC1 particles and absorb (actually probably fit into a vacant chloride site) on the mineral surface. The amine end of the collector molecule would extend into the solution phase and provide the air avid surface required for flotation. NaCl particles are floated by such collectors as aqueous molecules of fatty acid salt, RCOONa(,,), in which the positive inorganic end of the dipole is attracted to the negatively charged surface of the NaCl and, in this case, adsorb and probably fit into a vacant sodium site on the surface. The aminium cation, RNH~, should also be a collector for NaC1. For certain collectors, actual precipitates of the collector must be formed before a sufficient amount of the polar aqueous molecule is present to effect flotation. In a system of this type there is a three-way equilibrium between: Aqeous Molecular Solid Precipitate - A of the Collector (Not Dissociated) . Ionic Species (Dissociated). The controlling equilibrium is probably between the precipitated form of the reagent and the aqueous

Jan 1, 1969

By Alvinus Brown Wood

THE ancient copper-mines of Lake Superior, having been destroyed or covered by-modern mining-dumps, are not accessible to the present inhabitants of that region, and, since no more are likely to be found, some account of those already discovered, from one who has seen them, may be acceptable to the Institute. Early in May, 1855, 1 took a party of men to open an ancient pit on the Quincy mine-location. Mr. C. C. Douglas was the Agent.," as mine-managers were then called on Lake Superior. The Quincy Co. had previously done work on a fissure-vein, several hundred feet west of the Amygdaloid lode (afterwards called the Pewabic lode), on which was the ancient pit herein described. It was at this pit that the Quincy' main shaft was subsequently stink. The ancient pit showed an apparent depth of about 4 ft., but when cleaned out it was shown to be 14 ft. deep, having been filled up by the sliding-in of material composed largely of broken rock, taken out in sinking the ancient shaft, and left near its mouth. Midway of the shaft, and below water-level, was found a scaffolding, of white-birch poles,- which had been used as a landing, to assist in removing the excavated rock. The shaft was 7 ft. in diameter. The excavation had been done by first building fires in order to disintegrate the rock, as was proved by the abundance of charcoal found; then breaking the softened rock with hammers of diorite, such as is found in the greenstone range on Keweenaw point. These hammers had about. the size of large paving-stones. Only broken ones were found, the whole ones having been doubtless carried away for other work, such as could be traced on the lode for a hundred feet or more to the south. At the place where this shaft was stink, barrel-copper (i.e.,

Mar 1, 1906

By E. T. Dumble

(Cleveland Meeting, October, 1912.) FOR many years there have been occasional reports of the discovery of gold from a belt of the coast country of Texas which is underlain by deposits belonging to the lower Eocene. For the most part they have been treated as newspaper reports and no examination or record of them has been made. Among such, it may be mentioned that in 1896 there was a flurry over reported gold-discoveries -west of Luling and elsewhere in this belt, and in 1903 some prospect-shafts were sunk on the Gonzales branch of the Galveston, Houston & San Antonio railway, 3 miles below Harwood. During 1912, further discoveries have again brought the matter to our attention, and it may be of interest to record the facts as we have found them. Some years ago specimens were sent me, which were said to have been taken from certain beds on Gazley creek, and concentrated by washing in it rocker. In them were several particles of gold sufficiently large to be visible to the eye. Under the microscope they showed to be, with few, exceptions, sharp cornered, and not rounded as is usual with placer-gold. They were not filings, however, but their sharpness seemed rather to be due to a recent freeing from their matrix. One or two grains were rusty, and one copper-hued, but the most of them were tolerably bright. On examining the material of the samples small grains or fragments were found, of a yellowish brown color, which seemed to be of a finely-granular structure-possibly a sandstone. In these fragments I found particles of gold, one of them being large enough to be visible without a lens. Gazley creek empties into the Colorado river just north of Smithville, and for a few miles north of that place its banks show, beneath the deposits of more recent materials, the sands and clays of the Lignitic division of the Eocene, with lignite, shells of iron, etc.

Oct 1, 1912

By S. L. Hoyt

The writer has long been interested in seeking an explanation of the upper heat effect in the copper-tin alloys over the a + b range, first described in 1913. These notes are offered, not at all as the final explanation 'of this heat effect, but rather to indicate certain progress which has been made toward establishing what happens over this temperature interval. While working on the thermal analysis of the copper-rich kalchoids (copper-tin-zinc alloys), it was noted that those alloys containing major portions of tin and minor portions of zinc exhibited two marked heat effects, one at about 520' C. and the other at about 600" C., instead of the single effect which is generally observed in either of the two binary series. This matter was discussed with Dr. Guertler, who suggested that a heat effect at about 600" C. in the pure copper-tin alloys might be expected. This led to a more searching examination of the thermal critical points in the pure copper-tin alloys, with the result that a marked, although somewhat weak, heat effect was located at about 600. Somewhat later, this upper heat effect was discussed with Dr. Burgess, and it was requested that the Bureau of Standards make heating and cooling curves of one of these alloys for the purpose of removing any possible doubt as to the actual presence of the heat effect. Results obtained by the Bureau are given in Plate I. In an earlier paper1 differential curves were published showing that the heat effect occurred at constant temperature over the a + B range and increased in magnitude with the amount of B up to a point somewhat above 20 per cent. tin. No heat effect was noticed at this temperature in the eutectoid alloy. The existence of this heat effect seems to require a modification of the present copper-tin diagram in the a + B field, and it has been the object of the work here presented to secure the evidence upon which such a change should be based.

Jan 1, 1919

By Benjamin Tillson

The hammer drill rightly receives the credit for having made the one-man drill possible, and so many economies seem possible through the proper application of :different types of hammer drills to various mining, quarrying, and, excavating operations, that an indication of the economies effected by the New Jersey Zinc Co. at its Franklin mines may be of pertinent interest. When this company commenced its trials of hammer drills in 1907, these tools had not I been developed to one-fourth the capacity and refinement which they have at present. At that time it was frequently stated that such a small tool, drilling holes of less diameter than the reciprocating rock drill, could not drill enough holes in a shift to permit the placing of sufficient explosive to break a tonnage of ore comparable with that produced by the"' rock drills;" that the placing of small holes inclined upward, at angles steeper than 40° above the horizontal, could not be expected to produce results equal to the large flat, wet or dry, holes in the breasted back of an overhand stope, and would only shatter the ground so as to make the back unsafe. In' spite of these adverse opinions, the hammer drills first showed their superiority over both heavy and light reciprocating drills in raising and in stoping, and then in drifting and quarry work. As a result, all of the reciprocating drills at the Franklin mines were scrapped, three years ago, all of the mining work being accomplished with increased efficiency, as shown in detail in this article. With the advent of the hammer drill in this property, it was considered advisable to make comparative tests of all the tools accessible, and it has since been the policy to investigate the merits of any advance of the drilling art in order to get the maximum amount of work from the tools. The necessity of devising some means of standardizing drill tests, and of measuring the consumption of compressed air as well as the drilling speed, was early realized.

Jan 2, 1915

By F. Osmond

When a metal (whether a simple substance, an alloy, or a compound) presents, in each of the smallest parts to which it can be redueed by mechanical division, a constant chemical composition, it is defined as chemically homogeneous. But chemical hombgeneity by no means necessitates mechanical homogeneity. There are no perfectly amorphous metals. Crystalline forces, on the one hand, and tensions or compressions, on the other band, determined by icequalities of temperature in the mass during heating or cooling, give rise in every metal to the formation of geometric elements of structure. These elements may, moreover, assume perfect crystalline forms, with their planes of cleavage; or embryonic crystalline forms, segregated in the midst of. a paste of confused organization; or pseudo-crystalline forms of expansion and contraction, like those produced in the drying of gelatinous precipitates or (most frequently) these different forms associated. 111 either case the adhesions between two adjoining structural elements, respectively homogeneous, may be very different from the interior cohesion of each of these elements. The mechanical properties of this complex aggregate cannot be simple, and, when it is submitted to strains sufficient to produce deformation, the results may be very different according to the type of structure or the manner in which it is affected by the strains. It may be fairly said that a metal does not present a single resistance to tension, or a single resistance to compression, etc., but in fact, at least theoretically, as many resistances to tension, compression, etc., as it may possess coexistent features of structure; only, in any single test, it is the weakest of the resistances involved which makes itself evident. For further explanation, let us imagine a cylinder A B (Fig. I), formed of two similar halves A and B, placed together upon their common base x y. Such a system evidently presents no resistance to axial tension, while it would resist axial compression like a single

Jan 1, 1894

By B. D. Cullity, A. Freda

It is well known that deformation by cold drawing or swaging produces a kind of preferred orientation called fiber texture in metal wires. Such textures have been extensively studied by means of X-ray diffraction, chiefly by techniques in which the diffracted X-rays are recorded photographically. This paper describes some results obtained with a new method, involving the use of a diffractometer. X-RAY METHOD Since the pole figure of a material having a fiber texture is symmetrical about the fiber axis, there is no need to present the entire pole figure. Instead, texture data can be summarized by means of a curve showing the variation of pole density along any meridian of the pole figure, if the north-south axis of the latter is made parallel to the fiber axis. The position of a pole on the meridian is specified by the angle 9 between the pole and the fiber axis (wire axis). The X-ray method1 used here to measure pole density as a function of 9 actually consists of two methods, referred to as A and B. In method a, X-rays are reflected from the wire surface. Pole densities can be measured by this method from O = 90 deg down to a limiting value which is dependent on the Bragg angle 8 and is typically of the order of 30 to 40 deg. Method B involves diffraction from the wire cross section and covers a range of 0 values from 0 up to an angle sufficient to overlap the measurements made by method A. By a combination of the two methods, a complete pole-density curve can be obtained. However, method A alone, which requires no specimen preparation other than etching, can often reveal enough of the pole-density curve to provide complete information about texture components. Both methods require that the measured diffracted intensities be corrected for changes in absorption and diffracting volume with changes in 9. A11 intensities I reported in this paper are corrected diffracted intensities; they are propor-

Jan 1, 1960

By H. M. Chance

The Choctaw coal-field is a direct westward extension of the Arkansas coal-field, but its coals are not like Arkansas coals, except in the country immediately adjoining the Arkansas line. From the base of the coal-bearing rocks up to the top of the coalmeasures, I find a total thickness of at least 8500 feet. This great mass of coal-bearing rocks consists of an alternation of slates, shales, sandstones and coal-beds, with their accompanying under-beds of fire-clay. Only one small bed of limestone was observed. This occurs near the middle of the series; it is about eighteen inches thick, and quite arenaceous. The formation is naturally subdivided by seven or eight thick beds of sandstone, varying from 50 to 200 feet in thickness, the outcropping edges of which form a series of more or less bold " hogback " ridges, the interbedded shales and slate forming the intervening valleys. The base of the coal-series is a massive sandstone, ranging from 100 to 200 feet or more in thickness, lying immediately beneath the Grady coal-bed, which is the lowest known coal. In the district embraced between. the Missouri, Kansas and Texas railroad and the Arkansas State line, this sand-rock usually forms a bold semi-mountainous ridge. This is the ridge through which the St. Louis and San Francisco railroad passes at Bryan station, where the Grady coal-bed is opened and worked, from which point it can be traced westward without difficulty, passing about three miles north of Le Flor on the same railroad, thence west to the " Little Narrows " (which is merely a gap in the ridge), 'and beyond to a point two miles west of the Thompson-McKinney place, where it swings abruptly north for a mile or more, only to resume immediately its westward course, forming for some miles the northern boundary of the valley known as the " Boiling-Springs Prairie," beyond which it trends somewhat

Jan 1, 1890

HAVING promised you to write concerning the nature of ores in particular, I must tell you some general facts, especially those concerning the places, kinds, and manner of their existence as well as the tools which are used. However, you must know that according to good investigators these ores are found in many parts of the world. They show themselves almost like the veins of blood in the bodies of animals, or the branches of trees spread out in different directions. Indeed, careful investigators of minerals, wishing to show by analogy how ores are located in mountains, have drawn a large tree with many branches, planted in the middle of the base of a mountain. From its principal trunk extend various branches, some thick, some slender, exactly like real trees in mature forests. They think that these grow and enlarge continually and draw themselves toward the sky, ever converting into their own nature the most disposed adjacent materials so that finally the tips arrive at the summit of the mountain and emerge with clear sign, sending forth, in place of leaves and blossoms, blue or green fumosities,* marcasites with small veins of heavy mineral, or other composition of tinctures. From these things, when they are found, it is possible to make certain inference that such a mountain contains ores, and as the signs are more or less, so are the minerals plentiful and rich or poor. For this reason the prospectors for these things take heart according to the manifestations that they find, and with hope and certainty of profit they take all possible pains to mine with skill and expense those things that the signs have indicated. Often there are ores of such a kind and quality that they raise a man in wealth to the skies. For this reason men penetrate with eyes of appraisal and judgment within the mountains and see almost exactly the places where there is ore and the

Jan 1, 1942

By W. H. Newhouse

DURING the past few years the writer has been impressed by the close relation of many epigenetic orebodies with anticlinal structures. In the literature on ore deposits there is occasional mention that an oreshoot or district is on an anticline, but in most of the descriptions no weight or significance is attached to the relation, and usually the fact is concealed in a mass of structural detail. A few writers have stressed the relationship in a few districts or on a certain type of deposit. Church, Spurr, Butler, Stahl and Schuette have called attention to certain features, but the general extent of such a correlation has not been made known in any publication that the author has seen. A recent article1 on the localization of ore deposits, by well-known geologists, does not consider this common association. The author has seen in the field a number of the structural features described, and in addition has made a fairly complete review of the literature. This paper presents enough of the examples found to show the frequency of the relation to anticlines, and since only a few deposits on synclines are known, all of these of any importance of which the writer knows are mentioned. With certain qualifications which are discussed later, epigenetic ore deposits of replacement or vein type are mostly found where local upwarps of the earth's crust have taken place. Where formations antedating the ore deposits are present in the proper attitude to demonstrate vertical warping (i. e., more or less horizontal beds) the structural feature on which a mineral district, or mineralized area is located is almost always anticlinal, or domelike in nature. Some or even most of the ore deposits in a given district may be on the flanks of the upwarp, but few major districts are located definitely on downwarped areas. Synclinal basins within certain limits of size appear to be unfavorable to the type of fracturing that admits ore-bearing solutions.

Jan 1, 1931

By John Garcia

COAL MINING, as well as all the other major in-dustries of Russia, is controlled by the Soviet Gov-ernment by means of organizations in each dis-trict, known as "Trusts," such as the "Kisel Coal Trust" in the Urals, the "Donugol Trust" in the Ukraine, etc., and each Trust functions as a unit, reporting direct to the chief of the department of the government at Moscow. The responsible head of each Trust is usually a mem-ber of the Communist party and, filtered through his organization, one generally finds a fair proportion of Communists in "key" or important positions, such as purchasing agents and local managers or superinten-dents, but in the majority of places requiring technical or professional knowledge, or trained brains and ex-perience, little or no attention is paid to a man's political opinion provided, of course, he "behaves himself." These different Trusts were authorized or ordered by the Central Committee at Moscow to investigate the methods of mining and type of mines developed in all other coal producing, countries of the world, and after a period of several years of intensive investigation and study reported back to headquarters that the modern American mines were the most efficient, recommending that the program for the rehabilitation of the Russian coal mining industry should follow the lines of American practice. The Trusts were then authorized to negotiate with American engineering firms for technical service for mine designs, and invited Americans to send commis-sions to Russia to prepare and submit to the Technical Council one or more projects for a complete modern American-type operation adapted to the local conditions. A "project" is a preliminary set of designs on the entire mine, top and bottom, with specifications. cost estimates, production costs, schedule of operation, budget of expen-diture, etc., and is quite an elaborate and sizable under-taking-I might say, it took six of us working tooth and nail for over three months to finish our first project.

Jan 3, 1928

By Earl Oliver, J. B. Umpleby

It is believed that in connection with the study of unit operation by the Petroleum Division of the A. I. M. E. a review of the simple principles of unit operation would be helpful. To that end, the following discussion is submitted. It is not to be considered in any sense as the conclusion of the committee, but rather as material submitted for its consideration and represents at this time only the viewpoints of its authors. Growth of the Oil Industry In 70 years the oil industry has grown from a single well on Oil Creek, Venango County, Pennsylvania, producing 25 bbl, per day, to more than 400,000 wells scattered over five continents with a daily output of 4,000,000 bbl. In that time petroleum has expanded from its simple use as a medicine in a few localities to a multitude of diverse uses in homes of every country the world over. During those years the oil fields of the United States have produced two-thirds of the world's output and have shipped their excess production into almost every country. In those years several hundred thousand good wells in the United States declined into small ones and depleted shallow deposits gave way to deep zones; so that the United States crude oil industry gradually changed from one of low cost production to one of higher cost. Throughout its entire life it has labored under two serious economic disadvantages, namely, constantly recurring periods of demoralization through overproduction, and competitive development methods that are wasteful. Development of Foreign Competition During the transition from low to higher cost production in the United States, events even more significant were taking place in foreign lands. Jungles were tamed and deserts conquered. Oil deposits were found and developed until, in the words of Sir John Cadman, "the globe is now drenched with a commodity which, although necessary to life, involves but an irregular and sometimes meager expenditure of life in its

Jan 1, 1930

By P. G. Beckett

The problem of handling the large quantities of water encountered in the Old Dominion mine presents many features of interest. In the present paper are discussed the probable sources of water, the pumping equipment, the increased flow into the mine in the early part of 1915, culminating in the flooding of the 18th and 16th levels in March of that year, and the difficulties that were met with during the high-water period. I. PRELIMINARY The Old Dominion mine, situated 1 mile north of the town of Globe, Ariz., has long been one of the prominent copper producers of the State, and until the opening up of the copper schist deposits in the neighboring mines of Miami, was responsible for the greater part of the copper output from the Globe district. As the gradual exhaustion of its orebodies near the surface led to the downward development of the mine, more water was encountered in the western portions directly underlying the dacite formation until the drainage problem became a serious factor in the operation of the mine and in the economical extraction of the ore. A heavy inrush of water on the 10th level of the mine in 1906, preceded by still earlier water difficulties, rendered imperative the immediate installation of a pumping equipment capable of handling large flows of water. While the Old Dominion has been recognized as a wet mine since its early days and one in which the complete control of the water situation was of paramount importance in the development of the lower levels, it is chiefly in the last nine years, since the installation of the increased pumping equipment, that the mine has developed and handled large quantities of water. Its maximum pumping record was reached in the first six months of 1915, during which time, following a prolonged period of abnormal precipitation, the pumps handled 1,624,740,000 gal. of water; while in the month of March alone, over 407,000,000 gal. of water were pumped from the mine.

Jan 1, 1917

By Clarence E. Jackson, George G. Luther

THE ever increasing array of information concerning the measurement of the effect of the welding process on the properties of a steel is an indication of the tremendous effort that is being expended in this field. The methods that have been considered may be divided into two groups: first, those that measure directly the effect of welding on the ductility of a steel, and, second, those that observe the change in some property, such as the hardness of the heat-affected zone, and assume a direct correlation between this change and the resultant ductility. The nick-bend test is a direct method designed for studying the effect of welding on the ductility of a steel. The test specimen (Fig. I) consists of a bar cut from a plate with a bead weld on the surface. The specimen is prepared with a saw-notch placed so as to restrict deformation to the heat-affected zone under the bead weld when tested as a static bend. Failure is caused by rupture of the low-ductility metal in the heat-affected zone. The angle at maximum load is used as an index of the effect of the welding process on the material. In the development of the nick-bend test considerable scatter was noted in some of the results, although the agreement of duplicate specimens welded at the same time and tested consecutively was excellent. Upon further investigation it was found that the change in ductility was dependent upon the interval of time between the welding operation and the testing of the specimen. For the six steels of Fig. a, the angle at maximum load in four cases was doubled and in one case was tripled. All steels that have been studied show an improvement in the angle of bend for longer intervals between welding and testing. This same behavior has been found in weldability tests using the Navy T-bend

Jan 1, 1945

By Charles Becker

THE practice of drying phosphate in Florida is as old as the industry, which began a little more than half a century ago. The methods, however, have changed considerably. At first, the natural process of exposure to the sun and air was used, later supplemented by wood fires beneath open-air stationary dry kilns and drying towers of various designs. It was not until the early nineties that rotary driers came into use, and at first they were of very small design and fired with wood. As the industry grew and tonnage increased, so likewise grew the number and size of rotary driers, until today the largest installations are 6 ft. up to 7 ft. 6 in. in diameter, and 55 to 60 ft. long, fired with crude oil. The reasons for drying phosphate rock are: (1) to eliminate freight on water in the shipment and (2) to facilitate the good grinding qualities required by the buyers in their acidulation. Phosphate pebbles vary materially in natural characteristics and each property has a direct bearing on the processing. In making comparisons of cost and operating conditions, the following are usually taken into consideration: 1. The hard dense pebbles, which contain very little interior moisture and 6 to 8 per cent total moisture, usually produced from the low-grade deposits. 2. The lighter, porous pebbles, which contain 4 to 5 per cent interior moisture and a total moisture ranging from 9 to 15 per cent. 3. The product of recovery operations using oily reagents, containing from 15 to 25 per cent moisture. 4. The size of the pebbles. Usually the plus 5-mesh material is considered as "coarse rock"; the minus 5-mesh plus 24-mesh is "fine rock," and the minute particles below 24 mesh are called "concentrate." 5. The amount of moisture allowed in the dried product. The practice is generally to dry down to 1.5 to 2 per cent moisture. There is, however, an actual range in guarantee of from 1 per cent maximum to 3 per cent maximum.

Jan 1, 1936

By Lancaster Jones

The gravity magnitudes obtained by means of observations with the Eötvös balance in the field are necessarily resultant or total effects due to all abnormalities of mass distribution, including even the effects due to the ellipticity and rotational motion of the whole earth. Since the object of the survey is to isolate the effects which arise solely from some particular subterranean feature, and to deduce therefrom the configuration and extent of this feature, the first step is to eliminate from the observed effects all those due to "disturbing" (i. e., unwanted) features, whether above or below the surface of the ground. The disturbing features have different characteristics, according to their situation relative to the center of the balance and to the horizontal plane through the foot of the balance, or station point; this diversity was recognized by Eotvos, who divided the total effects into so-called Normal, Terrain, Topographical, Cartographical and Subterranean effects. This classification has been adhered to by most subsequent investigators, but the writer prefers to employ the term "three-dimensional," which really indicates the essential character of the class of effect known as "Subterranean," at any rate from the standpoint of the computer of effects. Before disturbing effects can be eliminated, the features must be measured up or surveyed, whether by topographical, mining, or boring methods, and then the effects of each feature calculated and subtracted from the total observed effects. After this the problem of interpreting the residual effects will itself necessitate the computation of the assumed feature, or even a series of trial features. The task of computing gravity effects is therefore of great importance. In the early work, by Eötvös himself, the computation practically ceased when the terrain and topographical effects had been calculated, but later surveys have demanded an ever-increasing extension in the technique of computation. Certainly in surveys designed to locate minerals, particularly ores, the calculations have to be extended far beyond those of Eötvös, while his methods of computing both terrain

Jan 1, 1929