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By Harry Seltz

SEVERAL investigators have measured the heat capacity of cementite, using different methods of attack, but the agreement between the values obtained cannot be considered good. Naeser1 has made measurements of "average heat capacities" of iron carbide between 1026° and 85° K., using a water calorimeter. His computed true specific heat at 78.1° K. is 11.22 cal. per gram-formula mass, which, if correct, is much too high for any reasonably accurate extrapolation to 0° K. The cementite used by Naeser was obtained from a steel containing 0.9 per cent carbon, by electrolytically dissolving out the iron in a neutral bath of ferrous chloride. The cementite remained as a coarse, crystalline, gray powder. Andes" has measured the specific heat of iron carbide, from 102° to 323° K., as it exists in steel. The specific heats of several slugs of steel of known iron carbide content were determined, and the specific heat of the iron carbide (Fe3C) calculated by plotting specific heat versus percentage of carbon, and extrapolating to pure Fe3C (6.7 per cent C). The heat-capacity values for temperatures below 100° K. were obtained by comparing the temperature-specific heat curve for Fe3C to that of Fe. Since the two were very similar in the range examined experimentally and approach more closely at low temperatures, it was assumed that near the absolute zero the form of the curve for Fe3C would be similar to that of Fe. Andes calculates for the entropy of Fe3C, S298 = 23.55 e.u. The heat of formation of Fe3C has been studied by several workers. Kelley' has reviewed these measurements and calculations, and selects those of Roth4 and Naeser5 as worthy of most consideration. Roth has given ?H = 5400 cal. ± 30 per cent as a result of his own and other work. Naeser has determined the heat of formation from Fe and different forms of carbon, and for graphite (ß) he finds OH = 5600 cal. Kelley accepts the rounded figure ?H = 5500 as the heat of formation at 298.1° K., but this value is quite uncertain.

Jan 1, 1939

By Edmund M. Warner

Any city dweller who has walked alone along a remote mine passageway has to be impressed by the eerie silence-the total absence of noise except for one's own breathing and scuffing of boots on the bottom. An underpound mine can have tremendous contrasts, from complete silence to the ear piercing clatter of percussion drills working in the mine roof. Noise in underground mining machines is both useful and detrimental. Without characteristic noises that are recognizable to miners, operators would have a more difficult job operating their machines. Noise serves as a warning of approaching machinery, and changes in noise give indication that breakdowns may occur. But excessive noise is a health hazard. In recognition of this fact, our congress included noise exposure as a part of the "Coal Mine Health and Safety Act of 1969." As [Fig. 1] indicates, allowable noise exposure is established by specifying a time duration permitted at different noise levels. This is the well known "Walsh-Healey" criteria which govern noise exposure in many industries. In most industries noise exposure is not a constant value. Noise emitted from coal mining machinery varies widely, and therefore interpretation of compliance is not a simple matter. Time, environment, instrumentation and machine productivity, as well as the designed machine characteristics affect the results. It is the purpose of this paper to present the underground coal face machinery noise problem from a manufacturer's point of view. Manufacturers are very much aware of their responsibility to alleviate the noise problem. Not infrequently, orders are received from coal operators that a given new machine must comply with "The Coal Mine Health & Safety Act" noise regulations. Such a request is indicative of the misunderstanding which exists with machine users, while indicating their desire to comply with the law. Obviously, if all machinery could be designed and used at some arbitrary low noise level, it would be possible to simplify the regulations. However, there still remains the pervasive problem of existing machines. Extensive investigation to create practical retrofit kits for existing machines, to substantially reduce noise have been only marginally successful. Certain machine mechanisms are inherent noise makers. The only really good solution is to substitute a quieter mechanism. Such overall new designs have been undertaken, and several examples are mentioned later in this paper. Before describing machine noise problems, it is necessary to define noise values. Noise levels are measured in decibels. The designation "DBA" is decibels measured on the "A" scale, or one in which the frequency sensitivity of the instrumentation is about the same as the human ear. The numbers are often misinterpreted because it is a logarithmic, rather than an arithmetic scale. In comprehending the numbers, it should be remembered that any increase of 3 dB doubles the sound power. In practical terms this means that two noises of equal power at the same distance away increases a dB reading by three. Consider [Fig. 2] showing a simplified case of a worker on a machine subject to

Jan 1, 1980

By H. H. Podgurski, J. C. M. Li, Y. T. Chou, F. N. Davis, R. A. Oriani

When an Fe-2 pct A1 alloy is nitrogemted at 500ºC with a gus tnixture (NH3-H2) in which the nitrogen activity has been kept Lou] enough to avoid the formation of iron nitride, a two-phase alloy is generuled which consists of AlN particles and a ferrite phase cotaining a heavy network of dislocations. The amount of nitrogen contained in such an alloy, when equilibrated with the nitrogenating atmosphere, far exceeds both that needed to satisfy the normal solution requirements of a Fe and that needed to convert all of the aluninuwi to AlN. This excess nitrogen is accounted for as being trapped on dislocations, adsorbed at the ferrite -AlN interface, and as an en-Iuznced lattice solubility in strained ferrite. This excessive uptake of nitrogen had previously been attribuled by other investigators to the formation of a nonstoichiornetric aluminum nitride. Isotope exchange experiments revealed various amomts of exchargeable N14 present in the originally nitrided samples that could not be removed by reduction with HS at 500ºC. This exchangeable nitrogen has been identified us that bound to the AlN -ferrite interface. Estimates of inter facial areas in alloys containing -3 pct by weight of A1N are as high as 10 sq m per g of alloy. ThE first1 of this series of papers described the experiments forming the basis for the elucidation of the mechanism of the formation of aluminum nitride particles within an Fe-A1 alloy. It was found that not only are dislocations necessary for the nucleation of the AlN particles but also the nitriding reaction in turn produces a dense network of dislocations in the ferrite matrix. It was also observed that nitrogen in excess of that needed for the formation of stoichiometric AIN is taken up by the alloy without the formation of an iron nitride. The present paper is an analysis of the excess nitrogen sorbed by the nitrided Fe-A1 alloy which considers the structure generated by the formation of the aluminum nitride particles. Because of the high density of dislocations, this system has proved to be quite useful in studying nitrogen-dislocation interactions. Wriedt and Darken2 have already reported such studies in a cold-worked ferritic steel. EXPERIMENTAL Nitrogen Sorption. The specimens of this alloy were cold worked (50 pct reduction) to 0.011 in. thickness and chemically cleaned in a 2:1 concentrated phosphoric acid-50 pct hydrogen peroxide solution before nitrogenation. The flowing nitrogenating atmosphere (11 pct NH3-89 pct H2) was established before the ni- trogenating temperature was reached. The same gravimetric and gas-flow equipment described in an earlier paper1 was also used in this investigation. Changes in nitrogen concentration were followed gravimetrically when establishing the isotherms. In the isotope exchange experiments, concentration changes were followed volumetrically. In some instances chemical analyses (Kjeldahl method) were used to check for material balances in both the gravimetric and volumetric procedures. Our objective was to obtain reversible nitrogen sorption isotherms for alloys equilibrated with NH3-H2 gas mixtures over a large range of nitrogen activity* and temperature. The *Defined as equal to PN H /P3/2 ,where P corresponds to partial pressure in atmospheres. Actually the nitrogen activity, aN, in the alloy equals K PNH3 /p3/2H2, where K is the equilibrium constant for the reaction NH3 = N + 3/2H2. upper limit for nitrogen activity was below that which would produce iron nitride; for reasons which will become apparent later, most of the sorption studies were made in the temperature range between 400" and 500'C. The alloy sample studied most extensively in this investigation was given a series of successive reductions (100 pct H2) and nitrogenating treatments at 500°C to attain a stabilized structure. Presumably some dislocations were lost during these treatments. Throughout most of the sorption studies, temperature was held at ± 1°C and the gas-phase composition was held to k0.2 pet NH3. Based upon the results of numerous diffusion experiments with this alloy* the 'Results to be published in a third paper of this series. times chosen for equilibration were considered more than adequate, Nitrogen Isotope Exchange. The first exchange experiments were carried out by circulating a measured quantity of H2 and NH3* (with a predetermined isotopic *The NH3 was synthesized over a synthetic ammonia iron catalyst using H2, and N2, enriched with N15. AS the NH3 was formed it was removed continuously from the gas phase by circulating the mixture through a refrigerated (78ºK) trap. When most of the nitrogen had been converted to NH3, it was distilled from the trap into a glass storage vessel. composition, N15/N14) over a nitrided specimen at 450°C in a closed glass system. Attempts to reach the exchange limit isothermally, i.e., an isotopic ratio (N15/N14) in the gas phase identical with the extractable nitrogen in the nitrided alloy, were futile. The exchange rate between the gas phase and the alloy was too slow, involving many days. To circumvent the slow exchange with the gas phase, measured amounts of N15 and N14 were introduced into the alloy by nitrogenating with an NH3-H2, mixture at 500°C containing an N15/N14 ratio of 7.76; the charged specimens were then sealed by allowing an oxide film to form over them in air, and in this final condition the specimens were subjected to 500°C in vacuum for various times during which isotope exchange was allowed to proceed within the specimen. It was estab-

Jan 1, 1970

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members who registered at Institute headquarters during July and August : R. H. Sweetser, Columbus, Ohio. C. R. Hill, New York, N. Y. Raymond Brooks, Goldfield, Nev. H. A. Morrison, Candor, N. C. Edward M. Shepard, Springfield, Mo. Frederick J. Patchell, Washington, D. C. Rudolf Gahl, Clifton, Ariz. Walter F. Pyne, New York, N. Y. Edmund von Maltitz, Pittsburg, Pa. Harvey B. Small, Mangangue, Colombia, S. A. M. K. Rodgers, Seattle, Wash. M. B. Cohen, Miami, Ariz. J. F. Erdlets, Jr., New York, N. Y. A. P. Watt, Newark, N. J. D. H. Ladd, Houghton, Mich. H. H. Stoek, Urbana, Ill. Roy F. Cornell, Santa Cruz, Cal. D. W. Brunton, Denver, Colo. W. B. Foote, Geneva, N. Y. C. S. Robinson, Youngstown, O. H. Sjogren, Stockholm, Sweden.

Jan 9, 1913

By Charles A. Ashburner

[The statistics contained in this paper were collected for the United States Geological Survey and communicated to the Institute, by permission, prior to their publication in the report on the Mineral Statistics of the United States for 1887.1 The total coal-production of Alabama in 1887 was about 1,950,000 short tons, the spot-value of which, at the mines, was $2,535,000. The coal-regions of the State lie in the extreme southern part of the Appalachian coal-field, the northern part of which lies along the western New York-Pennsylvania State line; between these limits, New York on the north and Alabama on the south, portions of the

Jan 1, 1889

By Theron Wasson

The oil and gas fields of Michigan that have been under development since 1925 are in an area that extends across the middle of the lower peninsula from northeast to southwest, a distance of about 200 miles, and with a width of about 80 miles. In 19 years 70 fields have been discovered. Most of these are relatively small when compared with other oil-producing areas. This is borne out by the fact that since the first wells were drilled these fields have produced a total of only 204,000,000 bbl. However, Michigan is still maintaining its production, for during the past five years the annual production has remained fairly constant at approximately 20,000,000 bbl. Production for 1943, as reported by the Bureau of Mines, was 20,682,000 barrels. Roughly, one third oi Michigan's production in 1943 came from the Reed City field, which was discovered in 1941. During the year, 237 oil wells were completed in Michigan in 1943. The decrease of 56 from the 1942 total is probably due to the continuance of Government regulations requiring a 40-acre spacing pattern over most of the state. Fig. I shows the principal oil and gas fields of Michigan, and the columnar section, Fig. 2, shows the principal producing horizons in relation to the section drilled. The data of Table I and Table 2 have been carefully checked with previous reports to eliminate errors. Six new producing areas were discovered during 1943 and five areas discovered in 1942 were developed during the year. Both the new discoveries and the 1942 discoveries that were developed appear to be small and relatively unimportant. Goodwell Field.—The best discovery of the year is the Goodwell field, T. 14 N., R. 11 W., Goodwell township, Newaygo County. This small structure was located by core testing done by The Pure Oil Co. in 1942 and early 1943. The first producing well, C. R. Harris No. I, was completed on July 5, 1943, ill the Traverse limestone at a total depth of 2742 ft., with ail estimated potential of 1100 bbl. per day. By the end of the year, 18 wells had been completed in this field and approximately 281,000 bbl. of oil produced. The field operated under proration of 262 bbl. per day per well from Oct. I to Dec. I; 150 bbl. per day per well after that date. Woodville Field.—The small Woodville pool, T. 15 N., R. 11 W., 3 miles north of the Goodwell field, was discovered by core testing by the Ohio Oil Co. The discovery well was completed on May 5, 1943, flowing 650 bbl. of fluid, including 18 per cent salt water the first 18 hr., from the Traverse limestone at a depth of 2810 to 2815 ft. Seven wells had been completed by the end of the year and 67,000 bbl. of oil had been produced. Development is now practically at a standstill because further drilling does not aDDear economically iustified.

Jan 1, 1944

By Theron Wasson

The oil and gas fields of Michigan that have been under development since 1925 are in an area that extends across the middle of the lower peninsula from northeast to southwest, a distance of about 200 miles, and with a width of about 80 miles. In 19 years 70 fields have been discovered. Most of these are relatively small when compared with other oil-producing areas. This is borne out by the fact that since the first wells were drilled these fields have produced a total of only 204,000,000 bbl. However, Michigan is still maintaining its production, for during the past five years the annual production has remained fairly constant at approximately 20,000,000 bbl. Production for 1943, as reported by the Bureau of Mines, was 20,682,000 barrels. Roughly, one third oi Michigan's production in 1943 came from the Reed City field, which was discovered in 1941. During the year, 237 oil wells were completed in Michigan in 1943. The decrease of 56 from the 1942 total is probably due to the continuance of Government regulations requiring a 40-acre spacing pattern over most of the state. Fig. I shows the principal oil and gas fields of Michigan, and the columnar section, Fig. 2, shows the principal producing horizons in relation to the section drilled. The data of Table I and Table 2 have been carefully checked with previous reports to eliminate errors. Six new producing areas were discovered during 1943 and five areas discovered in 1942 were developed during the year. Both the new discoveries and the 1942 discoveries that were developed appear to be small and relatively unimportant. Goodwell Field.—The best discovery of the year is the Goodwell field, T. 14 N., R. 11 W., Goodwell township, Newaygo County. This small structure was located by core testing done by The Pure Oil Co. in 1942 and early 1943. The first producing well, C. R. Harris No. I, was completed on July 5, 1943, ill the Traverse limestone at a total depth of 2742 ft., with ail estimated potential of 1100 bbl. per day. By the end of the year, 18 wells had been completed in this field and approximately 281,000 bbl. of oil produced. The field operated under proration of 262 bbl. per day per well from Oct. I to Dec. I; 150 bbl. per day per well after that date. Woodville Field.—The small Woodville pool, T. 15 N., R. 11 W., 3 miles north of the Goodwell field, was discovered by core testing by the Ohio Oil Co. The discovery well was completed on May 5, 1943, flowing 650 bbl. of fluid, including 18 per cent salt water the first 18 hr., from the Traverse limestone at a depth of 2810 to 2815 ft. Seven wells had been completed by the end of the year and 67,000 bbl. of oil had been produced. Development is now practically at a standstill because further drilling does not aDDear economically iustified.

Jan 1, 1944

By Leonard R. Weisberg

HE procedure of directional freezing by the Bridgman technique1 is frequently used in crystal preparation. On those occasions where the crystal is regrown, it can be advantageous to Crop part of the ingot before regrowth to achieve purification. This note describes some simple, yet interesting, observations concerning the effects of cropping an ingot between successive freezes. First, it is not effective to Crop the front end of an ingot, whether or not the distribution coefficient, k , of the impurities is greater or less than unity. This can be shown as follows. The concentration C, of an impurity in a directionally frozen ingot of length d with a uniform cross section is given by where x is the distance along the ingot, and C0 is the initial concentration per unit length. It is assumed in deriving this equation that diffusion is negligible in the solid, is complete in the melt, and that k is constant. Consider that a section of the ingot Ad is removed from the front end. Then the average impurity concentration in the remaining (d- Ad) section of the ingot can be shown by integration to be given by When the ingot is remelted and refrozen, the new impurity distribution is given by where xl is the distance along the refrozen ingot. Substituting the value of c into Eq. [3], one finds This is identical to Eq. [11 when x = (x, Ad), which represents the original impurity distribution in the (d - Ad) section of the ingot after the first directional freeze. Therefore, the cropping and re-freezing accomplished nothing. This can also be seen physically by realizing that the average impurity content in the melt after the first Ad section is frozen, is identical to that after the resulting ingot has been cropped and remelted. Hence, it is assumed in the following sections that only the tail end of the ingot is cropped. However, it must be realized that for impurities with k greater than one, the pieces cropped from the tail end are purer, and are therefore saved. After cropping an amount Ad from the tail end of an ingot, the average impurity concentration of impurities in the remaining portion of the ingot is given by wheref= d/d. For the case of k < 1, the purification is defined as c,/c. It is obvious from Eq. [5] that the purification increases asf increases, but the increase in purification is not large. For example, iff is doubled from 0.1 to 0.2, the purification increases by only 10 pct for k = 0.5, by only 24 pct for k = 0.1, and by 32 pct for k =0.01. Much smaller values off than 0.1 are not desirable since insufficient purification is achieved. These figures indicate that much larger values off do not lead to substantial improvement, especially considering that much of the original ingot is lost. Therefore, it is generally useful to Crop about 1/10 of the ingot to achieve purification. As compared to doubling the value off, it is much more helpful to remelt, refreeze, and crop the ingot twice. Using Eq. [51 reiteratively, and assuming f= 0.1, it is found that the purification after this process is found to be increased over the purification after a single freeze and cropping by 33 pct for k= 0.5, 450 pct for k = 0.1, and 4100 pct for k = 0.01. This indicates that considerable purification can be obtained by this procedure. However, if purification is the main goal, one should resort to zone refining,3

Jan 1, 1962

By Hsun Hu, R. S. Cline

The annealing behavior and the mechanism of re-orientation during recrystallization of iodide titanium cold-rolled 94 pct have been studied in detail. Results indicate that recrystallization occurs by the nucleation and growth of new grains, as in other common metals. Recrystallization nuclei form by the coalescence of subgraim, and the change in texture as a result of recrystallization is largely due to selective growth among the nuclei formed. The annealing of titanium is characterized by a wide range of overlap of the various stages of the annealing process, which may be responsible for a range of activation energies observed, and for the apparently gradual change in the annealing texture as a function of time or temperature. The deformation and recrystallization characteristics of titanium and zirconium are very similar. In cold-rolled strip, the deformation texture consists of two symmetrically oriented components, each having the basal plane laterally tilted at about 30 deg from the rolling plane and the [1010] direction parallel to the rolling direction. Upon annealing for recrystallization, the change in texture can be described, for simplicity,* as rotations around [0001].2&apos;6&apos;8 According to McGeary and Lustman,&apos; recrystallization occurs in zirconium through normal growth of the subgrains, which they called "domains", without the nucleation of new grains; and the magnitude of rotation around the [0001] axis increases gradually during the progress of recrystallization. If these conclusions were true, the mechanism of recrystallization in zirconium would be basically different from that in most metals, since it is commonly known that recrystallization with reori-entation always involves the migration of high-angle boundaries. In an attempt to clarify the situation, the mechanism of reorientation during recrystallization in iodide titanium cold-rolled 94 pct was studied in detail. The structural and textural changes upon annealing at various temperatures were examined by optical and transmission-electron microscopy, X-ray pole figures, pole density distribution measurements, and micro-beam techniques. EXPERIMENTAL PROCEDURE Material and Specimen Preparation. An iodide titanium crystal bar was are-melted and solidified in a cold-hearth crucible under a purified argon atmosphere. The solidified ingot had dimensions of approximately 3 by 1/2 by 3 in. One face of the ingot was somewhat uneven, but was as clean and shiny as the remaining parts of the ingot. Large grains with a Widmanstatten internal structure were clearly shown on the shiny surfaces, indicating the occurrence of P — a transformation upon rapid cooling from the melt. Analysis of the are-melted ingot indicated C 0.033, N 0.010, H 0.013, 0 0.002 in weight percent, and traces of iron, copper, and silicon as detectable impurities. The ingot was cold-rolled -40 pct to 0.300 in. thick with a reduction of 0.005 in. per pass. The defects on the uneven side of the ingot were then removed by machining. This reduced the thickness to 0.285 in. The piece was then recrystallized by annealing at 800°C for 1 hr in a fused silica boat charged into a fused silica tube furnace under a vacuum of 10~5 mm Hg. To refine the grain size, the recrystallized metal was again cold-rolled 40 pct to 0.170 in., then annealed at 700°C for 1 hr. These treatments yielded a strip with a uniform equiaxed grain structure, having a penultimate average grain diameter of 0.04 mm and a hardness of approximately 90 Dph. Final rolling reduced the thickness from 0.170 to 0.010 in., corresponding to a reduction of 94 pct. The strip was rolled in both directions by reversing end for end between passes. Surface lubrication was provided by oil-soaked pads attached to both rolls. Specimens of 1 in. length (for X-ray examinations) and +in. length (for hardness and microstructure examinations) were cut from the rolled strip, and a width of & in. was cut from the edges of each specimen by a jeweler&apos;s saw. These specimens were then etched in a solution of 10 cu cm HN03, 5 cu cm HF, and 50 cu cm H,O to 0.008 in. thick to remove the surface metal, as well as the distorted metal at the saw cuts, prior to annealing or measurements. To minimize any surface reaction with the atmosphere, all specimens were kept in an evacuated desiccator. Isothermal Anneals. All annealing treatments were conducted in vacuum in a fused silica tube furnace as described earlier. The temperature of the furnace was controlled to within *2"C. The specimen was placed in a fused silica boat, then pushed into the hot zone of the furnace. It took about 5 to 6 min for the specimen to reach the furnace temperature. After the specimen was held at temperature for a desired length of time the boat was pulled to the cold zone of the furnace; the heating-up period was excluded from the isothermal annealing time. Thus, the uncertainty in annealing time is higher for very short anneals, but negligible for long anneals.

Jan 1, 1969

By JOHN MARKLE

JOHN MARBLE, mining engineer, coal operator, philanthropist, member of the Institute since 1879, vice-president in 1903-04, has been paid the well deserved tribute of Honorary Membership. The presentation of the diploma was made at a luncheon in New York on Feb. 13, the citation reading: "In recognition of his work as an engineer and administrator of mines and his services to mining engineering education." Within the last month Lafayette University dedicated the new John Markle Mining Engineering Building, the gift of the eminent alumnus for whom it is named. In addition, Mr. Markle has contributed a maintenance fund for the carrying out of far-reaching plans for improving the mining courses to be given at the Institution. One of his theories is that quality rather than quantity of engineering graduates is the need of the profession. John Markle was born in Hazleton, Pa., in 1858. He received his degree of M. E. at Lafayette in 1880, and married Mary Estelle Robinson in New York City in 1884. Since 1880 he has been associated continuously with the firm of G. B. Markle & Co., and its successor companies. He has also been an official of numerous other important companies, although he is now retired from active business life.

Jan 1, 1930

By Gerard Matthes

ONLY in recent years has any practical headway been made in the application of aerial photography to geological problems, and up to the present time its principal value to the geologist and mining engineer has been in "areal geology;" i. e., the study of formations as revealed at the surface. The object of this paper is to set forth briefly the principal advantages that may be derived from aerial photographic data in geological work and to serve in a measure as a guide to those who may be con-templating its use. Geophysical prospecting has for object the locating of mineral under the surface. Inasmuch as the geologist&apos;s chief complaint in life is a dual one-inability to see under the surface and inability to visualize comprehensively what he does see on top of the ground-geophysical prospecting coupled with aerial photography should do much to lessen his burdens. To what extent aerial photography can be made a useful adjunct to geophysical prospecting remains to be proved, but the inference drawn here is that it holds many alluring possibilities. To avoid disappointments, it should be stated at the outset that to the :geologist or mining engineer an aerial photograph or mosaic is only a tool, the effecient use of which he must set out to master. Upon his skill and ingenuity in applying it to particular problems will depend largely the value of the results that he will obtain. Under the most favorable conditions an aerial mosaic or even a few loose photographs, because of the exceptionally comprehensive oversight which they afford of field data, such as dips and strike observations at isolated outcrops, local indications of faulting, mineral and fossil finds, greatly facilitate study and correlation, save much tedious foot work, and may repay their cost many times. Even so, types of country may be found where the most, skillful use of the best of pictures will produce results so meager as to render the cost of aerial photography entirely unwarranted.

Jan 1, 1928

By G. B. Sazuyer

DEVELOPMENTS respecting beryllium during the past year have been sufficient to center attention on it as likely to be the most important of any of the chemical elements that have recently found a place for themselves in technical industry. This importance is only potential, however, largely because adequate supplies of beryllium ore will be necessary. The beryllium industry will be only as great as the mines which support it. To find and develop large mines will be the problem. Chief of the immediate commercial developments in the United States is beryllium-copper and its espousal by Anaconda and Riverside even at present high prices. According to the pamphlets of these companies, it ap¬pears that beryllium is to copper nearly what carbon is to iron. When one considers that the tensile strength of pure copper is about 33,000 lb. per sq. in., but that the addition of 1.5 to 2.5 per cent of beryllium produces a heat-treatable alloy with a maximum tensile strength of 220,000 lb. or over, the analogy to carbon and iron is made strikingly, clear. Striking among the properties of beryllium-copper is its resistance to fatigue, claimed to be equal or superior to that of spring steel. It needs little imagination to foresee a great industry for this alloy alone.

Jan 1, 1934

By Wm. I. Weisman, C. W. Tandy

Consumption of fluorspar in the United States in the last ten years has doubled to 1.34 million tons. One main, reason for the increase has been the use of the basic oxygen furnace to produce steel which requires considerably more fluorspar than the open hearth. The increasing consumption of aluminum and fluorocarbon chemicals will require more fluorspar, Since 1964 domestic fluorspar prices have advanced over 70%. Maximum prices were attained in 1971 and remain stable. These higher prices have brought about the expansion of production capacity at many of the present mines and mills. Exploration has been intensified, resulting in new discoveries, which are being brought into production. Many deposits, heretofore considered uneconomical, are being reappraised for possible development. Companies who have not previously mined fluorspar are actively seeking and acquiring new properties. The outlook for the continued health of the domestic fluorspar industries is favorable at present prices; however, it is doubtful that production will be greatly increased. New production will have to come from presently inaccessible areas of much greater distance from consuming centers. Prices will have to be higher to support this production. Domestic fluorspar production meets only 20% of domestic consumption. Thus, reliance on imports on fluorspar in the future will become increasingly more critical.

Jan 1, 1975

By H. H. Reamer, B. H. Sage

Attempts have been made to predict the volumetric and phase behavior of naturally occurring hydrocarbon mix-turesl-6 but these methods have not been extended to the higher pressures and tem-peratures that are currently encountered in some producing formations. Furthermore, the methods of prediction at present avail-able have not been tested in a sufficient number of cases to ensure their applica-bility to all naturally occurring hydrocar-bon mixtures, even at the lower pressures and temperatures. For these reasons the behavior of a number of hydrocarbon mix-tures from a field in which the subsurface pressures are above 4500 lb. per sq. in.t and the temperatures are in the neighbor-hood of 250°F. was investigated. Method The objective of this program was to determine the volumetric behavior of ma-terial as it existed in the reservoir as a function of pressure, temperature and com-position. Strictly speaking, this cannot be accomplished in any simple fashion. How- ever, the variations in composition that are encountered within a producing reservoir may be approximated roughly by means of mixtures made up of two arbitrarily chosen constituents. Experience indicates that the liquid and gas phases from a high-pressure gas trap afford a simple source of material for this purpose. Throughout this discus-sion the samples of the gas phase and liquid phase from the production trap will be called the "trap-gas sample" and the "trap-liquid sample," respectively. The volumetric behavior of both of the trap samples was determined throughout the temperature interval between 100" and 250°F. at pressures up to 5000 lb. per sq. in. In addition, the behavior of eight different mixtures containing varying proportions of the two trap samples was studied throughout the same temperature and pressure intervals. The experimental results yielded information concerning the specific volume of the material as a function of pressure, temperature and the relative quantity of the trap samples. The relative amount of each of the paraffin hydrocarbons of lower molecular weight than n-hexane was determined for each of the trap samples. In addition, the specific weight, viscosity and average molecular weight of the hexanes-and-heavier fraction of the trap-liquid sample were determined as well as similar information for each of five fractions separated from this material by distillation. From these data the weight fractions of each of the components from methane through pentane were determined for the trap samples and eight systematically chosen mixtures. Materials The gas and liquid samples were obtained from the production trap of a well in the Rio Bravo field in California during the fall of 1939. Information concerning the condi- 70

Jan 1, 1941

By H. H. Reamer, B. H. Sage

Attempts have been made to predict the volumetric and phase behavior of naturally occurring hydrocarbon mix-turesl-6 but these methods have not been extended to the higher pressures and tem-peratures that are currently encountered in some producing formations. Furthermore, the methods of prediction at present avail-able have not been tested in a sufficient number of cases to ensure their applica-bility to all naturally occurring hydrocar-bon mixtures, even at the lower pressures and temperatures. For these reasons the behavior of a number of hydrocarbon mix-tures from a field in which the subsurface pressures are above 4500 lb. per sq. in.t and the temperatures are in the neighbor-hood of 250°F. was investigated. Method The objective of this program was to determine the volumetric behavior of ma-terial as it existed in the reservoir as a function of pressure, temperature and com-position. Strictly speaking, this cannot be accomplished in any simple fashion. How- ever, the variations in composition that are encountered within a producing reservoir may be approximated roughly by means of mixtures made up of two arbitrarily chosen constituents. Experience indicates that the liquid and gas phases from a high-pressure gas trap afford a simple source of material for this purpose. Throughout this discus-sion the samples of the gas phase and liquid phase from the production trap will be called the "trap-gas sample" and the "trap-liquid sample," respectively. The volumetric behavior of both of the trap samples was determined throughout the temperature interval between 100" and 250°F. at pressures up to 5000 lb. per sq. in. In addition, the behavior of eight different mixtures containing varying proportions of the two trap samples was studied throughout the same temperature and pressure intervals. The experimental results yielded information concerning the specific volume of the material as a function of pressure, temperature and the relative quantity of the trap samples. The relative amount of each of the paraffin hydrocarbons of lower molecular weight than n-hexane was determined for each of the trap samples. In addition, the specific weight, viscosity and average molecular weight of the hexanes-and-heavier fraction of the trap-liquid sample were determined as well as similar information for each of five fractions separated from this material by distillation. From these data the weight fractions of each of the components from methane through pentane were determined for the trap samples and eight systematically chosen mixtures. Materials The gas and liquid samples were obtained from the production trap of a well in the Rio Bravo field in California during the fall of 1939. Information concerning the condi- 70

Jan 1, 1941

TO THE BOARD OF DIRECTORS AND MEMBERS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS GENTLEMEN: Submitted herewith are the report of the Treasurer for the year 1945 and reports for the same year of the following standing committees: Membership, Admissions, Papers and Publications, Mining and &apos; Metallurgy (Magazine), and Library. To these reports you are referred for additional details. Membership Membership, counting all categories other than Student Associateship, continues the upward trend of the last 10 years, reaching a total, as shown in Table 1, of 12,081. The net gain of 406 would

Jan 1, 1944

By A. W. Schlechten, A. H. Larson

Equilibrium H2S/H2 ratios were determined as functions of temperature (500o to 900°C) and composition in a hydrogen-circulation apparatus. Within the composition range studied there exists a two-phase region of "Zr3S4" and "ZrS2". The upper composition limit of this two-phase region is hounded by a disulfide phase and is practically constant over the temperature range investigated. The lower composition limit of this two-phase region is bounded a "Zr3S4 " phase and varies appreciably with tem- perature. The upper composition limit of the homogeneous region of the disulfide phase is not definitely determined, but it appears to he bounded by the stoichiometric composition of ZrS2. The lower composition limit of the homogeneous region of the Zr3S4 phase could not he determined due to the extremely low values of the equilibrium H2S/H2 ratios. Various thermodynamic quantities are evaluated from the data. PUBLISHED free-energy data for the Zr-S system are practically nonexistent. Strotzer, Biltz, and Meisel1 measured the sulfur pressures for the reaction 2ZrS2(s) + S2(g) = ZrS3(s) in the temperature range 783" to 874°C. The average heat of reaction calculated from the temperature dependence of the sulfur pressure is -47 keal. It should be noted, however, that according to these investigators, the two-phase region as determined by sulfur pressure constancy under isothermal conditions extended from approximately ZrS2, 3 to ZrS2.7. From consideration of X-ray data they concluded that the homogeneous regions of the disulfide and trisulfide phases are ZrS1.8-2.0 and ZrS2.8-3.2, respectively. Hahn and coworkers2 have made a structure study of the zirconium sulfide phases. They summarized the zirconium sulfide phases as follows: the compounds ZrS3 and ZrS2 with narrow homogeneous regions, a "Zr3S4" phase with a homogeneous region roughly within the limits of ZrSl.5 and ZrSo.9, the compounds ZrS and Zr4S3, and a "Zr3S2" phase with a homogeneous region within the limits ZrSo.8 and ZrSo.5. It is noted that the compounds ZrS and Zr4S3 are only formed in the gaseous state through sublimation of a phase which has the approximate composition of the compound. This paper describes the determination of the stability of the zirconium sulfide phases by a hydrogen-reduction method in which hydrogen is circulated over the heated sulfide until equilibrium is attained. The resulting H2S-H2 mixture is then analyzed. Partial molar free energies, enthalpies,

Jan 1, 1964

By T. M. Berry

FOR the past several years it has been growing practice to install circular shafts at deep mining operations. Several factors have brought this about. Throughout eastern and midwestern coal fields circular shafts have been conventional for many years. Where large bodies of coal are mined, a production shaft may have a life of 20 to 30 years. Quantity production is essential; therefore the shaft must have a large cross-sectional area for larger skips and cages. Mechanical mining has become a necessity if a company is to stay in business today. Continuous mining machines and cutting, loading, and hauling equipment must be taken in and out of the mines. If the access shaft is not large enough there will be expensive dismantling and assembling. This has become a problem at many operations, particularly in the western sections where ore was originally mucked by hand into small cars and hoisted by a skip through a narrow rectangular shaft having small compartments. Mechanical loaders must be dismantled to wheelbarrow size to go into these mines.

Jan 7, 1957

By J. E. Russell

A brief review of the role of laboratory testing for characterization of host rocks for nuclear waste repositories is presented. Micro-and macro-scopic deformation mechanisms are discussed and constitutive laws being considered are reviewed. More information is available for rocksalt under expected repository conditions and, consequently, it receives more attention in our review. A brief comparison is made between the creep and constant strain-rate tests leading to a hypothesis that there may be systematic differences between steady-state conditions developed by the two test types. This difference is explained by considering specific power dissipated and work done on the sample. The hypothesis is tested against data for wet Westerly granite. In conclusion, progress has been made during the past five years but research and development should continue.

Jan 1, 1984

THE SECRETARY The year 1917 has been a notable one in Institute affairs. The usual activities, including meetings, publications, local section interests, library service, and so-forth, have been continued on at least the same scale as previously, and in addition the resources of the Institute have been placed without stint at the service of the Nation, not only for the active prosecution of the military side of the war, but even more especially in the industrial operations which form the very basis of modern warfare. The officers and directors of the Institute have labored both officially and individually, while the Institute as a body, through committees of, prominent members, and through many individual members, has given freely. Finally, Institute funds have been appropriated to an amount exceeding $5000 to accomplish the cooperation with Government bureaus, and provide committee expenses necessary for performing the services that have been given. The President of the Institute had a very large personal share in many of these activities, which will be described in the following pages, as well as in the President&apos;s own report. Many of the Institute&apos;s members are giving their whole time for. $1 a year, or less, and especial mention should be made of Herbert C. Hoover, Food Administrator, W. L. Honnold, Head of the Commission for Relief in Belgium, Mark L. Requa, Petroleum Administrator, Edgar Rickard and Charles W. Merrill of the Food Administration, S. A. Taylor of the Fuel Administration, W. L. Saunders, B. B. Thayer and Joseph W. Richards who .are giving a. large share of their time to the Naval Consulting Board, W. Y. Westervelt, W.0. Hotchkiss and Harvey S. Mud of the War Minerals Committee, David W. Brunton of the War Committee of Technical Societies, and hundreds of others whose names are mentioned in the Honor Roll of Members. It has also been a notable year in cooperation with sister-societies. The most important event under this head was the accession of the American Society of Civil Engineers into the fraternity of Founder Societies.

Jan 2, 1918