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Abel, Charles Edwin, Student, Univ. of California Los Angeles, Cal. '81 Ames, Marshall B., Blaine-Republic Co Republic, Wash. "81 Anderson, Norman John, Student, South Dakota School of Mines Rapid City, S. D. '82 Angst, Robert A., Jr., Student, Michigan College of Min. & Tech Houghton, Mich. '82 Apgar, James William, Student, Lafayette College Easton, Pa. '83 Armstrong, John R. Box 274, Neosho, Mo. '81 Armstrong, Robert H., Student, Lafayette College Easton, Pa. '81 Arnot, Paul H. 608 S. Acacia St., Compton, Cal. '81 Asel, Philip R., Student, Colorado. School of Mines Golden, Colo. '82 Atkins, William Robert, Student, Michigan College of Min. & Tech Houghton, Mich. '82 Augenthaler, Robert L., Student, New Mexico School of Mines Socorro, N. M. '82 Augustine, Robert W., Student, Alaska School of Mines College, Alaska. '82. Avery, Eugene A., Student, Montana School of Mines Butte, Mont. '82 Babcock, Norwood N., Student, South Dakota School of Mines Rapid City, S. D. '82 Baer, Jerome S., Student, Michigan College of Min. & Tech Houghton, Mich. '81 Baker, Robert C., Student, Pennsylvania State College.. 112 E. Beaver Ave., State College, Pa. '82 Baldwin, William C., Student, Univ. of Illinois Urban, III. '81

Jan 1, 1932

By Edwin T. Myskowski, Alfred H. Hesse

THE development by the U. S. Bureau of Mines of a process for purifying manganese by electrolysis has stimulated interest in manganese alloys. While recent publications have shown some alloys of manganese and copper to possess rather unusual properties, none have included information on tensile properties, which have an important bearing on the usefulness of the alloys. Manganese-copper alloys can be heat-treated, since the single phases that exist at high temperatures may be retained by quenching. According to Persson,1 when quenched alloys containing from about 30 to nearly 100 per cent manganese are reheated, alpha manganese is precipitated (Fig. I). Calculations based on Persson's X-ray data indicate that this decomposition is accompanied by a change in volume of as much as 5 per cent. The reason that this large volume change has not been noted probably is the slow rate at which equilibrium is reached by these alloys. In an investigation on hardening by cold-work and heat-treatment, Dean and Anderson' found that quenched alloys increase in hardness with manganese content and that high-manganese alloys harden very slowly with cold-work, while high-copper alloys harden much more rapidly. Heat-treatment has little effect on manganese-copper alloys containing less than 40 per cent Mn, and affects those alloys containing more than 40 per cent in accordance with their manganese content and heat-treating temperature. Dean and Anderson4 also found that cold-work increased electrical resistance of alloys containing from 50 to 80 per cent Mn, and that heat-treatment of alloys containing from 40 to 96 per cent Mn altered the electrical resistance considerably. Dean, Anderson and Potter5 have shown that the high vibration damping capacity that characterizes manganese-copper alloys containing 40 to 90 per cent Mn is affected by cold-work and heat-treatments. Highest vibration damping capacity at low stresses was obtained by heating for 2 hr. at 450°C. (842°F.) after quenching from solution temperatures. Preparation of Alloys.-The alloys for these tests were melted in a 17-lb. basic-lined high-frequency induction furnace using electrolytic manganese, grade A ingot copper and a 70-30 Cu-Mn master alloy (69.80 per cent Cu, 0.12 Fe, 0.04 Si, 0.006 S, 0.07 C, balance Mn). The manganese was heated slowly to expel excess dissolved gases and melted before the addition of copper. No fluxes or covers were used. The melts were cast in tapered iron molds and the ingots were reduced 90 per cent when forged to ½ -in. rounds. These rods were given 2-hr. solution treatments at temperatures that depended upon the composition (Table I). Tensile Tests.-The tensile specimens, 0.313-in. diameter (1.25-in. gauge length), which were enclosed in evacuated Pyrex

Jan 1, 1942

By Samuel S. Wyer

The following abbreviations have been used in the text: Cassier's, Cassier's Magazine. Eng. Lond., The Engineer (London). Eng. Mag., Engineering Magazine. Eng. News, Engineering News. Eng. Rec., Engineering Record. Eng. and Min. Jour., Engineering and Mining Journal. Engng., Engineering. Jour. Assn. Eng. Soc., Journal of the Association of Engineering Societies. Engr., The Engineer (Chicago). Jour. I. and S. I., Journal of the Iron and Steel Institute. Jour. F. I., Journal of the Franklin Institute. Mar. Eng., Marine Engineering. Mem. Soc. Ing. Civ., France, Memoires de la Socie'te' des Inge-nieurs Civils, France. Pract. Eng., Practical Engineer. Proc. Engs. Soc. of W. Pa., Proceedings of the Engineers' Society of Western Pennsylvania. Proc. I. C. E., Proceedings of the Institute of Civil Engineers. Proc. I. M. E., Proceedings Institution of Mechanical Engineers. Trans. A. I. M. E., Transactions of the American Institute Mining Engineers. Sci. Am., Scientific American. Sci. Am. Sup., Scientific American Supplement. Zeitschr. d. V. D. Ing., Zeitschrift des Vereines Deutscher Inge-niezcre.

Jan 1, 1906

By R. E. Head, E. L. Tucker

In the metallurgy of precious metals, it has been standard practice for years to use cyanogen compounds, so it was but natural that early investigators in the field of flotation should consider these compounds as possible flotation reagents. In Australian Patent 9508, of 1913, alkali cyanides were described as suitable reagents for the separation of heavy sulfide minerals, the reagents being employed either in an alkaline or neutral circuit. In U. S. Patent 1236501, of 1917, to John M. Tibbet, the use of cyanide in conjunction with soda ash or lime is described. One of the claims of this patent reads, "An improvement in the cyanide process for the treatment of ores comprising, mixing the ore with cyanide solution and oil and alkali: emulsifying the oil in the presence of the ore, the alkali and the cyanide solution, floating a portion of the values in the pulp by producing gas bubbles in the mixture and removing the values floated." More recently, Sheridan and Griswold, in U. S. Patents 1421585 and 1427235, describe a somewhat similar process and have successfully introduced it in the mill of the Timber Butte Milling Co. U. S. Patent 1429544, of 1922, to Stevens, describes the use of double cyanides of copper, zinc, and lead. The success of cyanide as a reagent in the differential flotation of lead and zinc sulfides in highly complex ores is proof that these patents have a solid foundation. Although the technique of their application to particular ores has been worked out in many cases, no one, so far as is known, has attempted to describe the nature of the action of the cyanide or to determine the ideal conditions for its application. It was the purpose of the present investigation to gather information on these points. Naturally this would have been an exceedingly ambitious program had the attempt been made to study the effect of cyanide

Jan 1, 1926

By Arthur H. Wilson

INTRODUCTION The stratified deposits of the coal measures are strongly laminated and exhibit a high degree of anisotropy. The stronger rocks in the sequence possess joints and shear planes, the coal itself has a closely spaced cleat pattern, and the softer rocks are capable of flowage. To calculate the general distribution of stress in such a medium by analytical means based on the theories of elasticity is difficult, and has not yet been satisfactorily achieved. Nevertheless, some estimate is required to aid the design of supporting pillars and permit the correct siting of main roadways. This is important when laying out districts for longwall extraction, particularly if the results of previous experience are not available in the area to be exploited. Although elastic stress analyses, including finite element analysis, may not be very appropriate, the basic equilibrium conditions will apply. These, combined with logical deductions based on observed fact, can be used to give appropriate solutions which experience has shown to be capable of giving acceptable results in the design of pillars associated with longwall workings. Constancy of cover load is one of the fundamental equilibrium conditions. When mining below ground, the cover is not removed, therefore the average vertical load after mining must equal the initial cover load. If mining produces a local decrease in load in any particular area, it must be balanced by an equivalent increase in load nearby. Bending moments in the strata above are capable of compensating for the turning moments which this redistribution of load may produce, and the existence of a "rear abutment", much discussed between 1950 and 1960, is not an essential equilibrium requirement. If the distribution of vertical stress is plotted three-dimensionally, then the load on any small element of area 6S will be o.6S, where o is the average stress. This also represents the volume of the "stress envelope" which lies above 6s. By making the individual areas very small and summing together, it is possible to show that the total load on any particular area can be found by calculating the volume of the stress distribution envelope which lies above it. A similar consideration applies to the stress distribution in a two-dimensional situation. If the stress distribution curve is drawn, then the area below any portion will represent the load per unit depth of section. For example, Figure 1 represents the possible stress distribution across a caved waste and associated ribside. If AW is the load deficiency [ ] These loads must balance, therefore area AW = AS, and if one can be deduced, the other will then be known. Attempts have been made to measure stress distributions in the ribside and in the waste. Stress meters in soft rocks such as the coal measures have not proved very effective. Those based on the measurement of strain have experienced difficulty in strata capable of flowage, high modulus stress meters suffer from cross sensitivity, and overcoming to obtain absolute stress is almost impossible. Load measuring instruments left in the waste have also proved largely ineffective, mainly as a result of the difficulties of protecting the leads in a caving environment. Certain logical deductions, however, can be made about the conditions in the waste. CONDITIONS IN THE WASTE Over the area of the waste the surface trough which develops is remarkably consistent, despite the geological variations which occur from coalfield to coalfield. In Britain, an accuracy of 210% is claimed for subsidence prediction based on width of extraction and depth of cover (National Coal Board, 1975). The subsidence in the USA is more variable (Adamek and Jeran, 1981), particularly with respect to the point of inflexion, but the same general pattern occurs. At the shallower depths the somewhat harder roof strata involved in the caving in the USA may suffer less compaction, giving reduced values of subsidence. Subsidence at intermediate horizons below the surface

Jan 1, 1982

The annual meeting of the Mining and Metallurgical Society of America was held on Tuesday, Jan. 8, 1918, at the Engineers' Club, New York, to elect officers and councillors for the ensuing year, to receive the reports of its retiring officers, and for the transaction of any business which might properly be considered. As usual, the meeting was divided into two sessions; the first, more properly the business session, was called to order at 2:30 p.m., with an attendance of 17 members; the second session took place at 8:30 p. m., immediately following an informal dinner, at which 40 guests and members participated. The latter was particularly interesting because it gave the meeting an opportunity to absorb first-hand information regarding the present crisis in Russia. Messrs. F. W. Draper and J. P. Hutchins, the latter a member and long resident in Russia, were the speakers of the evening.

Jan 3, 1918

By Albert S. Trube

The purpose of this paper is to clarify the definition of compressibility and to present a uniform basis upon which instantaneous compressibilities of liquids and gases can be compared. The equations gaverning the instantaneous compressibilities of imperfect gases are derived and the concept of pseudo-reduced compressibility is introduced. Part of the data presented by Brown, Katz et a1 on compressibility factors for natural gases has been rearranged. A graph of pseudo-reduced compressibility vs pseudo-reduced pressure for various pseudo-reduced temperatures is presented. The need for additional work in relating the compressibilities of liquids and gases is discussed. This information should be of value to reservoir engineers in making non-steady state performance calculations in gas reservoirs. It should be of further use irz pointing the direction for additional research in the nature of liquid and gas compressibilities. INTRODUCTION With the increasing use of steady and non-steady state well and reservoir data, there is a corresponding increase in the importance of the various factors entering into such calculations. Increasing emphasis is being placed on the necessity for obtaining reasonably accurate estimates of the physical properties of the reservoir fluids well in advance of the more accurate laboratory data. One such factor is the isothermal coefficient of expansion of the media which are transmitting and attenuating the non-steady state pressure waves. The average isothermal coefficient of expansion, or "compressibility" is a complex function controlled by the physical properties of the formation and the fluids contained therein. The isothermal expansion coefficients for reservoir gases are usually quite variable, in many cases being highly-pressure sensitive. The coefficients for reservoir liquids tend to be pressure sensitive, but not nearly so much as reservoir gases. The coefficients for solids, usually expressed in terms of a "modulus of elasticity" are relatively insensitive to pressure variations within their elastic limits. For this reason, and also because many previous applications have been limited to rel- atively small pressure ranges, there has been a tendency to ignore the variable nature of isothermal expansion coefficients and treat them as constants. Also, the term "compressibility" by which these coefficients are generally designated is commonly confused with a similar term, z, used to define the deviation of an imperfect natural gas from the perfect gas laws. A clear distinction should be made at the outset between the term "compressibility", which is an isothermal coefficient of expansion of a substance, and the term "compressibility factor", z, which refers to the deviation of a gas from the perfect gas laws. Although the scope of this paper is limited to the compressibility of single phase natural gases, it is definitely related to the problem of accurately estimating the compressibilities of single phase hydrocarbon reservoir liquids, which will form the basis of a future presentation. BASIC PRINCIPLES The coefficient of isothermal compressibility of a substance, c, is usually determined from pressure-volume or pressure-length -measurements depending upon whether the substance is single phase gas, liquid, or solid. A convenient method for making such estimates for a finite change in pressure and volume at constant temperature is to use the well known equation V1-V2/V1 (p2 - p1) .....(1) Eq. 1 is negative because the volume of a confined substance decreases as the pressure is increased. In this case V1 > V2 and p2 > p1. This equation is useful in approximating the compressibilities of single phase gases and liquids undergoing small pressure changes. It is evident, however, that this equation is almost identical with the determination of Young's modulus of elasticity for solids. If the assumption is made that change in length is directly proportional to change in volume, as would very nearly be the case for a steel rod in tension within its elastic limit, then E5=-L1 (p2 - p1)/L1 - L2 .......(2) in which E. is the isothermal expansion coefficient, or Young's modulus of elasticity, for a solid. And further, for this special case L1 (p2 - p1)/L1 - L2 .......(3)

Jan 1, 1958

By F. W. Smith

Within the Northern Pennine Orefield, England, intersections of fluorite veins are generally richest in ore, and their recognition enables investigation of the ore potential of the intersecting bodies. A method, based on routine analysis of fluorite for yttrium, has been used with success in mines of the district to predict the location of intersections in partially developed fluorite-bearing ore bodies. This short note is intended as a brief introduction; the details of United Kingdom applications are to be published at a later date. Geology The Northern Pennine Orefield is the second largest fluorspar-producing region in Britain. The associated minerals galena, sphalerite, chalcopyrite, barite, and witherite have all been extensively worked in the past but, with the exception of a single barytes mine, all of these operations are now abandoned. Galena alone is recovered as a byproduct of fluorspar beneficiation. At the present time two companies are producing about 38,000 tpy of fluorspar from high grade vein ore bodies, and a number of concerns are actively prospecting in old lead workings. The mineralization is localized in veins and replacement flats within favorable lithologies in an alternating limestone, sandstone, shale sequence. Since the thickness of individual beds is not great (generally less than 20 m), vein bodies tend to be ribbon-shaped, with length greatly exceeding width and height (Dunham). They thus present difficult exploration targets for conventional diamond drilling techniques. Ore grade varies greatly along the veins, which can change rapidly in character from mineral stained fault gouge to massive mineral bodies up to 10 m in width. It has been known for a very long time that the richer ore bodies tend to be associated with vein intersections in favorable beds. It is assumed that vein fissure intersections provided vertical channelways through which hot ore-bearing brines were able to ascend from deeper cavities in the sequence. Thus investigation of intersections at other horizons generally yields further ore bodies. Technique The relative concentration of yttrium in fluorite is a good indicator, in the North Pennines, of the direction of flow of mineralizing fluids. In all of the ore bodies so far studied in detail in this region, the concentration of yttrium increases markedly in the direction of vein intersections that are believed to have acted as feeder zones to the remainder of the bodies. The reason for this relationship is probably connected with the degradation of soluble rare earths-fluoride complexes by the changes in various physicochemical parameters of the hydrothermal fluids as they entered the ore body cavities from the feeder zones. The simultaneous release of free fluoride ions also contributed to the increased ore values in these intersection zones. Yttrium values in fluorite taken from a longitudinal traverse of the western ore body, Redburn mine, Rookhope, are plotted in [Fig. 1.] The position of a major vein branch and three cross veins are clearly indicated by yttrium maxima. The cross veins themselves contain up to 2.5 m of low grade fluorspar ore. The exact positions of B and C were unknown previous to the geochemical survey. Similar results have been obtained for several other veins and ore bodies in the area. Clean fluorspar was collected as bulk samples from within 300 mm of the vein wall and, since the vein infilling is simple, with mineral growth from the walls inward, analyses of the samples are considered comparable along the length of the ore body. A number of samples taken from the center of the vein show a

Jan 1, 1975

IRON AND STEEL COMMITTEE ALBERT SAUVEUR, Chairman A. A. STEVENSON, Vice-Chairman HERBERT M. BOYLSTON, Secretary, Abbot Bldg., Cambridge, Mass. Guilliaem Aertsen, Henry M. Howe, E. Gybbon Spilsbury, John Birkinbine, _Robert-W. Hunt, J, S. Unger; William-H. Blauvelt, J:-E: Johnson, Jr., Felix A: Vogel; Charles A. Buck, Charles Kirchhoff, Leonard Waldo, Ernest F. Burchard, Richard Moldenke, William R. Walker, F. D. Carney, Charles F. Rand, William R. Webster, James Gayley, Joseph W. Richards, Frederick W. Wood. Henry D. Hibbard, C. F. W. Rys, There will be a meeting of the Institute in Pittsburg on Oct. 8, 9, and 10, 1914. This meeting will be under the joint auspices of the Iron and Steel Committee, the Committee on Coal and Coke, and the Committee on Petroleum and Gas. The iron and steel papers will probably be presented on Oct. 8. The following papers have been received and accepted and will be read at the October meeting.

Jan 6, 1914

By S. R. B. Cooke, C. E. Thurston, G. Kudo

The trend toward utilization of low grade iron ores means that more efficient methods must be developed for their concentration. The collecting ability of fatty acids derived from fish oils has been extensively investigated by Cooke.' Tuna oil, a byproduct of the tuna canning industry, is one of the lower priced fish oils. Utilization of tuna oil fatty acids as collectors in the flotation of iron ore might be economically feasible under certain market conditions, especially if their efficiency were high. Crude or unfractionated tuna oil fatty acids, and five fractions derived therefrom, were tested for their ability to concentrate a commercial specularite ore from northern Michigan. A commercial fatty acid derived from tall oil, and commonly used in nonsulfide flotation, was used as a reference. The crude fatty acids were obtained by simple saponification of tuna oil. Fractions A and B were obtained by acetone precipitation of the crude acids at -5O and -2S°C, respectively. Fraction C was obtained by a partial fractional distillation at 12S°C and at a pressure of 3y in a centrifugal molecular still in order to remove the shortest and longest chain fatty acids of tuna oil as well as oxidation products present in the original mixture. Fractions D and E were prepared by a chilling process in order to precipitate the unwanted saturated fatty acids. Yields and iodine values of the materials used are listed below: The seven samples were used as collectors in a laboratory procedure patterned after the commercial process for flotation of Michigan specularite ore. The outline of the procedure is that previously described1

Jan 1, 1962

By David L. Holt

It is well-established that hydrostatic pressure distribution is hardly achieved during uniaxial compaction of powders. All the previous investigations1-4 give consistent results and this variation is attributed to the die-wall friction. The conclusions are based on measurements of the density of very small portions of the compact. Although the analysis of the density or the strain distribution in the compact is very helpful in obtaining information about the stress distribution within a powder compact, it does not describe the problem from a more fundamental point of view. The densification in metal powder compacts takes place chiefly by plastic deformation (ignoring particle rearrangement) at the points of contact of the powder particles. The onset of yielding and subsequent growth of the contact areas (for spherical powders) take place fixed by a constant stress equal to three times the yield stress in tension or compression,5-7 assuming little or no work hardening. Therefore, by deforming spherical powders in the die and measuring the contact areas on each particle, the load at each contact point can be determined. In the present investigation, this was done by hot-pressing uniform spheres of lead, K-Monel, and sapphire. The details of the experiment have been described elsewhere.' The spheres were studied for the size and the number of contact points on each particle using a specially designed goniometer. It was found that the deformed faces that were approximately normal to the direction of pressing were about 2.2 times larger than those parallel to the direction of pressing. Fig. 1 shows the typical deformed sphere. A detailed study showed that the mean value of the contact areas on each sphere was within 5 pct for all the spheres in the die (ignoring those touching the die walls and the top and bottom of the die).' The spheres touching the die walls and the top and bottom of the die were found to have larger contact areas (8 to 10 pct) which indicates higher pressures in these regions of the compact and thus higher compact densities in these regions. These results show that density distribution calculated from such an experiment will give results consistent with the previous investigators. It is concluded, therefore, that the pressure distribution in the die is better understood by studying contact areas on each particle. 'R. Kamm, M. A. Steinberg, and J. Wulff: Trans. TMS-AIME, 1947, vol. 171, p. 439. 'Pol Duwez and Leo Zwell: I. Metals, 1949, vol. 1, p. 137. 'G. C. Kucynski and I. Zaplatynskyj: Trans. TMS-AIIME, 1956, vol. 206, p. 215. 'R. P. Seelig and J. Wulff: Trans. TMS-AIME, 1946, vol. 166, p. 492. 'H. Hencky: Z. Angew. Math. Mech., 1923, vol. 3, p. 241. "J. Ishlinsky: I. Appl. Math. Mech. USSR, 1944, vol. 8, p. 233. 'D. Tabor: Proc. Roy. Soc. (London), Ser. A, 1948, vol. 192, p. 247. 'Ashok K. Kakar and A. C. D. Chaklader: 1. Appl. Phys., 1967, vol. 38, p. 3223. Superplasticity in 60Zn-40Al David L. Holt THE occurrence of superplasticity in Al-Zn alloys is of interest because of its possible industrial exploitation.' The eutectoid composition (78Zn-22A1) has been the most extensively studied;'-= neck resistant flow and high strain rate sensitivity of flow stress (characteristic of superplasticity) are associated with a micron-size grain conferred on the alloy by an homo-genization and quench.5'6 Compositions away from the eutectoid have received comparatively little attention, especially from the viewpoint of relating the structural

Jan 1, 1969

By T. A. Rickard

A knowledge of the principles of punctuation is essential to effective and intelligible writing, for the ease and pleasure of the reader, and even his understanding, may depend upon the choice and the placing of punctuation marks. To 'punctuate' is to mark with stops or points; the word comes from the medieval Latin punctuare (punctuatus), which in turn is derived from the Latin punctum, a point. The purpose of punctuation is to show the manner in which the writing is to be understood; to indicate the relations between parts of a sentence and between successive sentences. To some extent "it does for the eye what vocal stress does for the ear", but especially it marks logical relations. Some punctuation marks, such as those indicating admiration, exclamation, and interrogation, are rhetorical as well as grammatical, but most of the common ones are logical, or grammatical. My discussion will be confined to grammatical punctuation in ordinary writing. .'The problem of punctuation in text matter", as George Summey * says, "is to employ words, points, and paragraph breaks in such a way as to achieve at the same time clearness; proper distribution of emphasis, and the desired kind of movement." The criticism of the punctuation of a sentence or of a group of sentences is not final until the context, within the paragraph, is read. A paragraph is a sentence or a group of sentences forming an independent unit of the composition; it represents a unit of thought. A multiplicity of paragraphs produces a choppy effect; 'on the other hand, paragraphs of. excessive length are tiresome, because the belaboring of one unit of thought wearies the reader. The aim should be to

Jan 1, 1931

By Cornelius F. Kelley

SEVENTY-FIVE years ago, in Wilkes-Barre, Pennsylvania, 22 men of vision banded together to initiate this great organization. Ideals and emotions mingled and united in the declaration of a twofold purpose: first, the more economic production of minerals and metals, and second, the promotion of greater safety and welfare for each man so employed-tacit recognition of the inseparability of humanitarian and utilitarian concepts of world progress. The members and honorary members then, as now, were mining engineers and associates from allied walks of life. Under the able guidance of David Thomas, our first president and outstanding ironmaster of the time, there were elected 46 members and associates, and the foundations of the Institute were laid. Conceived in a turbulent postwar era, the problems then faced had some similarity to those we face in this time of war-bashed uncertainty. With a Civil War behind them and once again dedicated to a spirit of national endeavor, they surveyed the landscape, then surged ahead toward a beckoning industrial horizon. That effort has never been relaxed. Poised upon the threshold of a new century, rancher, banker, engineer and businessman paused to contemplate and evaluate his natural endowments. Surrounded by immeasurable God-given wealth, necessity inspired

Jan 1, 1947

Discussion of the paper of M. E. Lormbardi,. presented at the New York meeting, February, 1915, and printed in Bulletin No. 9S, February, 1915, pp. 209 to 215. I. N. KNAPP, Ardmore, Pa.-Some years ago I made a swinging spider to carry a string of casing in a way somewhat similar to that described in this paper. The ground I tried it in was too soft for its successful operation. The spider had a central one-flange bushing to carry the slips. Under this flange and on top of the spider was a properly protected ball runway, or ball bearing, which permitted rotating the casing when it was in place and supported by the slips.

Jan 5, 1915

By P. R. Celmer, Leonard R. Weisberg

THE principle of fractional crystallization has been successfully used to prepare high-purity (99.999 pct) Ga. Hoffman and Scribnerl removed single crystals of gallium solidifying in a gallium melt, while Zimmerman2 grew single crystals from the melt by the Kyropolous technique. In contrast, attempts at purifying gallium by zone refining have been less successful. ichards, reported that despite the passage of 40 zones through a gallium ingot, there still remained 5 to 70 ppm each of Cu, Fe, Ca, Mg, Si, Al, and Ag. Previously, Detwiler and Fox4 detected only one impurity, Pb, segregating in zone-refined ingots. These surprising results prompted an investigation of the factors controlling impurity segregation in gallium. Possible reasons for this were insufficient diffusion of impurities in the melt; recontamination of the melt by its oxide film which is not affected by the passage of the zone; reaction of gallium with the boat; sudden freezing of gallium following supercooling, especially since gallium easily supercools to and trapping of impurities at grain boundaries. Impurity segregation tests were carried out by directionally freezing gallium using the Bridgman rnethd, modified in that the molten gallium is lowered out of a furnace into a slush of dry ice and trichloroethylene, thus minimizing supercooling. Since the gallium is contained vertically, the oxide film is in contact only with the tail end of the melt. It was found that Teflon makes an excellent crucible for gallium since it is quite pure, non-reactive, translucent, flexible, machinable, and is not wet by gallium. The gallium crystals could be grown at various speeds, and the melt could be vigorously stirred by a Teflon rod moving through the gallium in a vertical reciprocating fashion. Single crystals could be grown by placing a solid Teflon plug at the bottom of the melt drilled out in such a way to cause the solidifying gallium to follow a winding path. Thus, even if many crystals are originally nucleated, only one grain will predominate. The grain structure of the gallium crystals was revealed by an etchant composed of equal volumes of HC1, HNO3 and HF, diluted with water to half strength. Emission spectrographic analyses were carried out on samples removed from the front and tail ends of the resulting gallium ingots. Typical results of this study are summarized in Table I. The rate of freezing in all three cases was about 1 in. per hr. It can be seen that even though stirring of the melt does help, it is even more important to grow a single crystal of Ga in order to obtain good segregation of impurities. The effect of crys-tallinity on the segregation of impurities was previously observed6 in the directional freezing of germanium; however, in this case, the effect was much less pronounced. This dependence of impurity segregation on the crystalline perfection of Ga may be related to its thermal conductivity which is the most anisotropic of all metals.7 The anisotropic thermal conductivity can cause the solid-liquid interface to be nonuniform, thus leading to trapping of impurities during freeing, and therefore reduced segregation. In conclusion, it is indicated that zone refining of gallium would be more successful if seeding and similar precautions are taken to insure single crystal growth. The authors are indebted to Mr. H. H. Whitaker for the spectrographic analyses and to Drs. B. Abeles and F. D. Rosi for helpful advice and encouragement throughout the course of this work. This research was supported by the Electronics Research Directorate, Air Research and Development Command, under Contract No. AF33(616)-5029. REFERENCES 'J. 1. IToffmon and B. T. Scribrer: I. Research h'atl. Bur. Standards, 1935, "01. 15, p. 205. 'W. Zirnmerman: Science, 1954, vol. 119, p. 41. %J. L. Richards: Nature, 1956, vol. 117, p. 182. 'D. P. Detwiler and W. M. Fox: I. Metals, 1955, "01. 7, p. 205. 5P. W. Bridgman, Proc. Am. ilcod. Sci., 1925, vul. 60, pp. 305,385,423. "S. L1. Christian: private c ommuni cation. 'K. W. Powell: roy. Sac., 1951, vol. 209, p. 525. 'W. G. Pfann: Zone Re fining, p. 20. John Wiley and Sons, Inc., New York, L058.

Jan 1, 1962

By O. Jay Myers

THE war effort has furnished the necessary impetus for better magnesium foundry practice. Four or five years ago, there were but a few formulas in general use for cores and mixtures for magnesium castings. Certain sands, binders, and inhibitors were specified and the proportions of these materials in each mixture were maintained between very narrow limits. As more and more war industries entered the field, much research was carried out and methods and practices were improved. Magnesium founding is still in a state of flux; therefore it is not uncommon to find one foundry spraying inhibitors on its cores, and another foundry using sand mixtures with incorporated protective agents. The basic core or dry-sand mold mixture for magnesium in use today is compounded with sand, core oil or resin binder, cereal, and moisture. Core oil or resin binder are added for baked strength while the cereal binder and moisture are for green strength. The normal mixtures (based on the weight of the sand) contain from 0.5 to 1.5 per cent of both cereal binder and core oil, and the moisture content varies between 1.5 and 5 per cent. The ratio of core oil to cereal binder varies from 60:40 to 40:60, while the correct amount of moisture depends upon the method of coremaking. PROTECTIVE AGENTS In all magnesium practice, protective agents are used in conjunction with the core and molding sands to prevent oxidation of the metal. The use of these inhibitors is not novel, but publications covering this field are not entirely adequate. Beck1 says Magnesium alloys decompose water to form magnesium oxide, hydrogen being liberated in the process (Mg + H20 -+ H21 + MgO). This reaction results in the blackening of the skin and the appearance of areas of porosity on the casting surface, the cavities of which are filled with a grey oxide powder (these are termed `burns'). Although sand cores for magnesium castings are thoroughly dried during the baking cycle, burning will take place on the castings unless the metal is protected properly. This type of burning is more difficult to define than the "water-magnesium" reaction cited by Beck. A possible explanation may lie in the following equation: 2Mg + 02 -s 2MgO Here, the source of the oxygen is not water, but the air in the mold cavity, together with the chemically combined oxygen in the core-binding media. Generally, two methods are used to prevent this reaction from taking place.

Jan 1, 1945

Plans for the Petroleum Division during the ensuing year are in process of development, in contemplation of the usual fall meetings in the Mid-Continent and California areas, as well as the annual meeting to be held in New York in February, 1936. Houston, Texas has been suggested as the place for the Mid-Continent fall meeting, the exact date to be announced shortly. During the past year, the Division's technical programs, as in former years, have emphasized the wide fields of engineering endeavor in the petroleum industry yet remaining for more thorough investigation and discussion. An effort has been made to bring an international interest into the proceedings of the Division by inviting the participation of prominent foreign technologists. This viewpoint should promote a continuation in 1935 of past high standards, afford a more thorough understanding of problems throughout the membership, and maintain the Institute's position among the various technical organizations functioning particularly in the oil-producing and refining areas. In the list of subjects proposed for the fall meetings is the problem of estimating petroleum reserves. Various factors requiring study will include productive sand volume, porosity, average permeability, saturation, and types of recovery. Research papers are proposed dealing with energy consumption per unit of oil recovered, reservoir pressure or energy loss relationship to the usual volumetric method of estimation, and the study of oil and gas segregation within the reservoir. Other subjects tentatively suggested include new casing practice in relationship to wells producing from several productive zones, progress in lifting methods, repressuring, advanced methods in drilling economies, and the economics of conservation. Although the threat of overproduction yet remains, to a lesser degree than during the past few years, intensive activity is now being directed towards the discovery of new petroleum reserves. This situation undoubtedly will influence, in some considerable degree, the channels through which technical activities will be directed. A continuation of the commendable work on production statistics for the various oil-producing states and foreign countries has been effected. The usual papers dealing with the general economics of the industry will be reserved for the annual New York Meeting. The Stabilization Committee maintains its membership of nationwide authorities, and interest is manifest in new developments to meet the changing requirements of the industry.

Jan 1, 1935

By E. F. Sumner, C. K. Eilerts

A partial differential equation was developed and programmed to compute the cumulation and flow of the liquid phase of a gas-condensate fluid. It was found that such cumulation near the wellbore may attain saturations permitting liquid flow within periods of the order of 1 day. The radius at which this saturation obtains advances toward the external reservoir boundary with continued recovery, although it may move only 2 to 5 percent of that distance during the productive life of the well. This relatively high saturation can cause a serious dimunition in delivery capacity. The pressure dilferential required for flow of gas through a formation with such saturation may be as much as three times greater than the corresponding differential in a formation where saturation is less than 2 percent. Because of the radial geometry, total reservoir pressure differential required for flow with a zone of relatively high liquid saturation about the well was indicated to be two to three times greater than without the saturation. INTRODUCTION A computing program developed by the authors 1 to integrate the partial differential equation for transient radial flow of gas-condensate fluids required a prevalued function, W(Po) = kD(p0)/M(p0)z0(Po).......(1) related to cumulation of condensate in pores of the reservoir as pressure declines. Methods were available for relating mobility to saturation, saturation to liquid-vapor volume ratio, liquid-vapor volume ratio to pressure and, hence, mobility to pressure to obtain W(pD). However, certain assumptions had to be made in advance of program execution concerning movement of the liquid phase and change in radial distribution of liquid saturation as recovery progressed. Because reservoir fluid mobility and related pressure gradients are markedly dependent on liquid saturation, it was desirable to eliminate the necessity for these assumptions and in this respect improve the reliability of a result obtained by integration. Experimental research was begun to determine the relationship of variables that control the reservoir flow of low liquid-vapor ratio fluids. With the porous medium partly saturated, permeability to a two-phase flowing fluid could not be measured because the viscosity was unknown. Viscosity could not be measured without knowing permeability of the liquid-containing medium; but mobility, the ratio of permeability to viscosity, was measurable. This property, and liquid-vapor volume ratio of the flowing phases, have values determined by nature of the fluid and porous medium and, in addition, were found to be pressure, velocity and saturation dependent. A program developed by Kniazeff and Naville 2 for computing multicom-ponent, two-phase flow used polynomials to represent saturation dependence of permeabilities for gas and for liquid phases, and an effluent viscosity constant under reservoir conditions. The authors developed a program based on a partial differential equation of similar mass balance origin but designed to represent distribution of an unlimited number of components between gas and liquid phases utilizing the experimental information available as to variable dependence. Attention was given to liquid-vapor volume ratio of the flowing phases, a property which is essential as a liquid saturation boundary condition. A program for computing implicitly saturation increase at uniform intervals along the drainage radius was combined with an existing program for calculating pressures, and the two were used alternately in an iterative solution for both saturations and pressures. The function W(pD) needed for calculating pressures was replaced by the ratio of mobility to compressibility factor. BASIC EQUATIONS The partial differential equation for calculating

By T. S. Lundy, J. I. Federer

A graphical method has been developed and tested for separating the effects of grain boundary and lattice diffusion in polycrystalline materials. The method is based on the assumptions that for unidirectional diffusion from a plane source of radioactive material, the penetration of activity far into the specimen from the source is due solely to grain-boundary effects, and 2) pure grain-boundary penetration is described by a linear plot of log activity vs the perpendicular distance x from the source. The former is based on the fact that at any temperature the grain-boundary diffusion coefficient is always very large relative to the lattice diffusion coefficient; and the latter is based on the derivation of Fisher.1 Using these criteria along with appropriate penetration data (in this case, data for the diffusion of Cb95 in pressed and sintered UO2) one first plots the data as log activity vs x2 and as log activity vs x, as shown by curves 1 and 2, respectively, in Fig. 1. A tangent line to curve 2 for large x (curve 3) is then transferred to the x2 plot as curve 4. The subtraction of curve 4 from curve 1 yields curve 5 which represents only lattice diffusion and may therefore be related to the diffusion coefficient by using the appropriate solution to Fick's second law. It should be noted that the method has inherent inaccuracies for small and large values of x2 and only the subtraction at intermediate values can be used. For the illustrated specimen the calculated diffusion coefficient is 3.4 X 10-11 sq cm per sec at1445°C while data using a single crystal of UO2 at the same temperature yielded a value of 2.9 x 10-11 sq cm per sec.2 The same method of subtracting grain-boundary diffusion effects to obtain lattice diffusion coefficients has been successfully used to determine self-diffusion coefficients of Th230 in polycrystalline thoria.

Jan 1, 1962

By I. J. Jansen

Introduction The Surface Mining Control and Reclamation Act (PL 95-87) lays a new challenge before the surface mining industry by requiring that prime farmlands must be reclaimed to equivalent or higher levels of yield as nonmined prime farmland in the surrounding area (section 510d). We must now evaluate the situation and plan a mining and reclamation program that will achieve that objective. We must recognize that soil and land needs vary with intended land use and climatic setting. Also, various site conditions determine the potential for constructing a productive soil and the best procedures to accomplish that end. It is necessary to plan the land reconstruction program on a site by site basis in order to achieve the best results. Discussion The Prime Land Concept Terms like prime agricultural land have been used loosely for many years to refer to lands that are highly productive and well suited to agricultural use. The concept of what qualified as prime land varied considerably from one geographic area to another and from one person to another. The term prime farmland, as used in PL 95-87, has recently been defined quite

Jan 1, 1982