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By J. H Lightfoot, Stuart E. Buckley

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

Jan 1, 1941

By J. H. Lightfoot, Stuart E. Buckley

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

Jan 1, 1941

By B. A. Rogers, K. O. Stamm

BECAUSE it is the basis of the economically important operation of hardening steel by quenching, the A3 transformation in iron has been the subject of numerous investigations. Although the contributions to this subject are interesting, no general review will be given here. Readers who care to follow the matter further are referred to the comprehensive summary by Cleaves and Thompson,1 which covers the literature to about 1935. Their references to 53 papers on the subject suggest that further investigation is hardly justifiable. However, considerable interest has developed recently concerning the reversibility of the transformation. From thermodynamic considerations, the transition ought to occur at the same point on heating or cooling, if the change of temperature is sufficiently slow. Yet all of the earlier investigators found a difference of several degrees. Burgess and Crowe,2 who used thermal methods, obtained average temperatures of 912° for Ac3 and 900°C. for Ar3 on electrolytic iron. Their data indicate a considerable range of temperature over which the change occurs, both on heating and on cooling. Terry3 measured the susceptibility in the critical range and estimated from the steepest parts of his curves that Ac3 came at 9180 and Ar3 at 903°C. Ishiwara4 was one of the first investigators to report a shorter interval between the temperature of the change in the two directions. He measured the change of susceptibility of kaolin-coated samples of steel, in a hydrogen atmosphere, at rates of heating and cooling so low that about 3 or 4 hr. were required for the transformation to complete itself. His results show some variability between samples, but indicate that the difference between Ac3 and Ar3 is in the vicinity of 6°C. Roberts and Davey5 measured the space lattice in pure iron in the vicinity of 900°°C. and concluded that a change occurs reversibly between 907° ± 3° and 9100 ± 3°C., probably between 907° and 910°C. Wells, Ackley, and Mehl6 made dilatometric determinations of the Ac3 and Ar3 points in samples of hydrogen-treated carbonyl iron maintained under a vacuum. They used three rates of heating and cooling: 2°, '1/2°, and 1/8°C. per min. and found the spread between the two points decreased with low rates. At the slowest rate, the Ac3 transition occurred at 909° to 909.5°C. and the Ar3 change at 907°C. in three of the samples believed to contain the lowest percentages of alien elements. They concluded that if the rate of temperature change and the content of alien elements were low enough, the A3 transformation would be completely reversible at 909.5° ± I°C. The question of reversibility is an interesting one and when some iron with especially small percentages of alien elements became available the opportunity to conduct an investigation was welcomed. This iron was prepared by the Division of

Jan 1, 1941

By AIME AIME

WITH a brilliance undimmed by hard times, the annual dinner on Wednesday evening, Feb. 17, was a complete success. More than 600 members, friends and ladies gathered early and filled the anterooms of the grand ballroom of the Commodore Hotel, while the president's reception was in progress, and then at the sound of the gong and with the music of the orchestra, rising above the happy din of conversation thronged to their seats at the tables. Following the "potage Ambassadeur"-probably to eliminate a very real hazard-the usual toy balloons appeared and a gay and lively scene, punctuated by multitudinous explosions, ensued, as the hundreds, of variously colored spheres bounced yon and hither until their gaseous existence was ended on the glowing end of a cigar or cigarette. On the speakers' dais sat C. E. Beecher, Chairman Petroleum Division; J. Vipond Davies, representative of A. I. M. E. on the Alfred Noble Prize Committee; Corbin T. Eddy, Alfred Noble Prize recipient; A.' S. Tuttle, Vice-president American Society of Civil Engineers; W. C. Mendenhall, Director U. S. Geological Survey; George C. Bateman, representing the Canadian Institute of Mining and Metallurgy; Paul D. Merica, Institute of Metals lecturer and Chairman James Douglas Medal Committee; Champion Herbert Mathewson, James Douglas Medalist; Robert E. Tally; retiring President; G. Temple Bridgman, toast-master; Scott Turner, incoming President; F. W. Bradley, William Lawrence Saunders Medalist; Fred Searls, Jr., Chairman William Lawrence Saunders Gold Medal Committee; Arthur Notman, President Mining and Metallurgical Society of. America; Robert J. Grant, Director U. S. Mint; Landon F. Strobel, Chairman New York Section; Howard Scott, recipient of Robert W. Hunt Prize; George. B. Waterhouse, Chairman Robert W. Hunt Prize Committee; F. M. Becket, Chairman Iron and Steel Division; Ora E. Clark, recipient of the J. E. Johnson, Jr., Award; Richard Peters, Jr., Chairman J. E. Johnson, Jr., Award Committee; E. C. Bain, Howe Lecturer; Sam Tour, Chairman Institute of Metals Division; and H. Foster Bain, Chairman. Charles F. 'Band Foundation Committee. ' Each was heartily applauded when introduced by Mr. Bridgman, as was Mrs. Tally, who also made a bow. The toastmaster made graceful reference in introducing Mr. Strobel, to the large part the latter had taken in planning the meeting.

Jan 1, 1932

By M. Cohen, R. J. Teitel

There is considerable interest in beryllium because of its low density (1.84 g per cu cm), high modulus of elasticity (40 X 106 psi), high melting point (1280°C), and special nuclear characteristics. Moreover, it has fair resistance to corrosion and oxidation. However, the purest beryllium known to the authors is relatively brittle at room temperature, and cannot be fabricated readily. The search for improved properties leads naturally to investigations of beryllium alloys and the phase relationships upon which they are based. The present paper is concerned with the alloys of beryllium and iron, primarily from the standpoint of the equilibrium diagram. Iron was selected (1) because of its all-round importance in metallurgy, and (2) because the beryllium-iron system is known to be quite complex. The most recent diagram in the literature is that of Gaev and Sokolov,' and covers only the iron-rich end up to 16 wt pct beryllium. Beryllium markedly restricts the austenitic field, closing the gamma loop at about 0.4 wt pct (3 at. pct). On the other hand, beryllium is soluble in a-ferrite up to a maximum of 7.5 wt pct (34 at. pct) at the eutectic temperature of 1160"C. The eutectic composition lies at 10 wt pct beryllium (42 at. pct) and corresponds to a mixture of or and FeBez (called j3 in the present paper). The solid solubility of beryllium in the a phase decreases with decreasing temperature, and makes precipitation-hardening possible. These findings substantiate the earlier work of Oester-held,2 Wever and Mueller3 and Laissus.4 In addition to the FeBe2 (ß) mentioned above, Misch6 has reported on FeBes, and indicated evidence for another compound containing still more beryllium. A preliminary diagram by Gordon,5 not hitherto published, is given in Fig 1. Besides the phases previously named, there are shown a solid solution of extended range (e), a compound of limited solubility (t), and a high temperature phase (7). Beryllium is designated as 8. The t field contains the compound composition FeBea, and the f phase undoubtedly corresponds to the beryllium-rich compound found by Misch.6 The region around the { phase was proposed by R. J. Teitel based on Gordon's data. The details of the diagram are self-explanatory. It was the unusual complexity of this system that prompted the authors to undertake the present studies. By the same token, more emphasis was placed on the beryllium-rich than the iron-rich end of the diagram. Exprimental Details RAW MATERIALS The beryllium employed in this investigation was one of the purest grades available. Its chemical analysis after vacuum melting is given in Table 1. The metal assayed 99.4 wt pct beryllium. Vacuum melted electrolytic iron of purity shown in Table 1 was the source of iron.

Jan 1, 1950

By L. L. McMurray

Ilmenite is the most important raw material for manufacture of titanium dioxide.' Industrially, several other products are made from ilmenite, the most important of which are: ferro titanium, ferro carbon-titanium, copper-titanium, titanium carbide and titanium nitride. The production of titanium metal is still in the laboratory stage because of the difficulty of extraction and as yet no important application for the metal has been found. Ilmenite has received considerable attention as an industrial raw material. Imports of ilmenite concentrates for the first nine months of 1941 were 156,737 short tons, the chief source being Travancore, India.2 Domestic produttion of ilmenite has heretofore been confined to Amherst and Nelson Counties, Virginia, where a complex rutile, ilmenite, and apatite ore is mined and treated to utilize all three of these minerals. A recent report3 has described development of the large titaniferous magnetite ore body at Tahawas, New York, where it is expected that 800 tons of ilmenite concentrates, containing 48 per cent TiO2 will be produced daily. Additional domestic production is expected from a large ilmenite deposit recently opened in caldwell county, North carolina. Flotation tests indicate that a high-grade concentrate containing 53 per cent TiO2 can be made from the North Carolina ore. Prospecting of domestic ores in other areas has been reported.' It appears that increased domestic production of ilmenite may well save considerable shipping space so vitally needed in these times. The composition and chemical structure of pure ilmenite is given by Dana as: FeO, TiO2; Ti, 31.6 per cent, Fe, 36.8 per cent, O2, 31.6 per cent. This composition is variable in that some iron or titanium may be replaced, giving a variable iron-titanium ratio. As an example, the iron-titanium weight ratio of ilmenite in Caldwell County, North Carolina, has been determined to be 0.94 (using 97.1 per cent ilmenite concentrate obtained by heavy liquids on minus Iso-mesh ore) compared with theoretical 1.16. No rutile was noted in this ore to account for the low value. This North Carolina ore is free of magnetite, which is a common associate of ilmenite ores. In view of a large potential production from North Carolina, the Tennessee Valley Authority conducted a study of methods of concentration of that ore, of which the results are reported herein. The Ore Five samples of Ore were taken from the deposit at various exposed locations and were mixed for the study and testing. An attempt was made to proportion the amount of weathered and unweathered portions in making the composite sample, so as to approximate actual operating conditions. An examination of representative specimens of the sample showed the following general facts: 1. The black mineral comprising nearly 70 per cent of the ore is ilmenite.

Jan 1, 1948

By L. L. McMurray

Ilmenite is the most important raw material for manufacture of titanium dioxide.' Industrially, several other products are made from ilmenite, the most important of which are: ferro titanium, ferro carbon-titanium, copper-titanium, titanium carbide and titanium nitride. The production of titanium metal is still in the laboratory stage because of the difficulty of extraction and as yet no important application for the metal has been found. Ilmenite has received considerable attention as an industrial raw material. Imports of ilmenite concentrates for the first nine months of 1941 were 156,737 short tons, the chief source being Travancore, India.2 Domestic produttion of ilmenite has heretofore been confined to Amherst and Nelson Counties, Virginia, where a complex rutile, ilmenite, and apatite ore is mined and treated to utilize all three of these minerals. A recent report3 has described development of the large titaniferous magnetite ore body at Tahawas, New York, where it is expected that 800 tons of ilmenite concentrates, containing 48 per cent TiO2 will be produced daily. Additional domestic production is expected from a large ilmenite deposit recently opened in caldwell county, North carolina. Flotation tests indicate that a high-grade concentrate containing 53 per cent TiO2 can be made from the North Carolina ore. Prospecting of domestic ores in other areas has been reported.' It appears that increased domestic production of ilmenite may well save considerable shipping space so vitally needed in these times. The composition and chemical structure of pure ilmenite is given by Dana as: FeO, TiO2; Ti, 31.6 per cent, Fe, 36.8 per cent, O2, 31.6 per cent. This composition is variable in that some iron or titanium may be replaced, giving a variable iron-titanium ratio. As an example, the iron-titanium weight ratio of ilmenite in Caldwell County, North Carolina, has been determined to be 0.94 (using 97.1 per cent ilmenite concentrate obtained by heavy liquids on minus Iso-mesh ore) compared with theoretical 1.16. No rutile was noted in this ore to account for the low value. This North Carolina ore is free of magnetite, which is a common associate of ilmenite ores. In view of a large potential production from North Carolina, the Tennessee Valley Authority conducted a study of methods of concentration of that ore, of which the results are reported herein. The Ore Five samples of Ore were taken from the deposit at various exposed locations and were mixed for the study and testing. An attempt was made to proportion the amount of weathered and unweathered portions in making the composite sample, so as to approximate actual operating conditions. An examination of representative specimens of the sample showed the following general facts: 1. The black mineral comprising nearly 70 per cent of the ore is ilmenite.

Jan 1, 1948

By Oliver Bowles

Slate is a fine-grained rock that has a more or less perfect natural cleavage, permitting it to be split readily into thin, smooth sheets. According to a definition established by the American Society for Testing Materials, slate is "a microgranular crystalline rock derived from argillaceous sediments by regional metamorphism and characterized by a perfect cleavage entirely independent of original bedding, which cleavage has been induced by pressure within the earth." Origin and Character Slates have originated from sedimentary deposits consisting largely of clay. Such materials were carried by streams and deposited in seas or lakes in successive horizontal beds. Other materials such as calcium carbonate, sand, or gravel may have been deposited over the clays, and the pressure of these superimposed materials gradually consolidated the materials below into bedded deposits of shale. Shale is a stratified rock formed by recrystallization of the clay plus adsorbed potash into the mica, sericite. Shale has neither the strength nor the splitting properties of slate since the mica is fine and the flakes unoriented, and the quartz grains do not interlock. Many shales, however, have been subjected to intense metamorphism. Mountain-building forces ever at work in the earth's crust may crumple, squeeze, and fold the shales. At the same time, accompanying high pressures and temperatures changed the original minerals into mica, interlocking quartz, or chlorite. Both mica and chlorite consist of minute tabular sheets or flakes with perfect cleavage. The intense pressure and movement tend to orient these flakes in parallel positions normal to the direction of pressure. The parallelism of the flakes results in the tendency to split with ease in one direction, which has been termed "slaty cleavage," and which is the outstanding characteristic of slate. Actually, the cleavage is through the cleavages of the individual micaceous plates. The original bedding of the slate is often folded and contorted, and the slaty cleavage commonly cuts across it at sharp angles. Composition MINERALOGICAL COMPOSITION The most abundant mineral in most slates is white mica (sericite), a hydrous silicate of potash and aluminum. It is present in very small flakes recognizable only with a microscope. Small grains of quartz (silicon dioxide) are also abundant and are regularly distributed among the mica flakes. The mica-like mineral, chlorite, is usually present in considerable quantities. Chlorites are of several kinds, the more common being hydrous silicates of aluminum and iron or magnesium. Other common minerals present in small quantities are rutile, clay, hematite, pyrite, carbonaceous matter, feldspar, zircon, tourmaline, calcite, dolomite, and siderite. The general range of the chief constituents is about as follows: Sericite, 38 to 40; quartz, 31 to 45; chlorite, 6 to 18; hematite, 3 to 6; and rutile, 1 to 1 ½ pct. CHEMICAL COMPOSITION Results of many analyses indicate that clays, shales, and slates differ little in chemical composition. The changes that take place during metamorphism are confined largely to rearrangement of the elements into new minerals with accompanying changes in physical properties such as hardness and cleavage. The general

Jan 1, 1960

By Marie Kinzel

LOS ALAMOS, New Mexico, the birthplace f the atomic bomb, is one of the most famous-and mysterious-places in the world. It leaped into fame on Aug. 6, 1945, when the first atomic bomb burst over Hiroshima. Unheard of until that day, its present life is as hidden from most people as was its very existence in pre-Hiroshima days. Then, those who did know of it dared not breathe their knowledge. "What do you tell your wife when you go to Shangri La?" was the favorite quip of the few consultants who made regular trips from east or west to Los Alamos during the tense months when the bomb was in the making. Security regulations made it impossible even to hint at the rigid secrecy surrounding the project. The puzzled wives in question knew only that their husbands had top priority on airplane flights to Albuquerque. When they had verified the safe arrival of the flight, they undoubtedly breathed a sigh of relief. If they could have visualized the rest of the trip, the sigh of relief would have been replaced by a state of tizzy, until a telegram came saying "Arriving home on Flight X" (on a nice safe airplane).

Jan 1, 1946

By Emma Smith, R. W. Guard

INVESTIGATION of the nickel-rich end of the Ni-Zr system has been prompted by an interest in the effect of small amounts of zirconium in high temperature alloys. Hansenl presents a hypothetical diagram based on the work of Allibone and Sykes,2 who investigated the system up to 44 atomic pct (55 wt pct) Zr by metallographic means. Since the alloys they used were melted in Alundum crucibles they were probably contaminated with appreciable amounts of aluminum. They found two compounds which they called Ni3Zr and Ni4Zr. Hayes, Roberson, and Paasche3 identified a compound NiZr (50 atomic pct Zr) with a melting point of 1470°C. Such a high melting compound is not compatible with the observation of Allibone and Sykes2 hat a eutectic is formed near 50 atomic pct. The alloys containing up to 60 atomic pct Zr were melted in an inert atmosphere in a noncon-sumable electrode arc furnace. Analysis of most of the alloys indicated negligible loss of zirconium. The alloys were examined in the as-cast condition and also after annealing for 6 hr at 1175°C (or 1000°C for the alloys between 25 atomic pct and 45 atomic pct). Metallographic specimens were etched using mixtures of HF-HNO3-H2O or acetic acid- HN0,-H,O. The specimens for the solidus determinations were wrapped in molybdenum foil and sealed in evacuated quartz tubes. Specimens to be heated above 1300°C were enclosed in zirconia tubes inside the quartz to prevent reaction with molybdenum. The solidus determinations were carried out by heating the specimens at various temperatures for a few minutes and then examining the interior structure metallographically to determine at what temperature melting began. The 150 mesh powders for X-ray analysis were annealed in an evacuated quartz tube for 2 hr at 540 °C to remove cold work. Alloys with 22.5 atomic pct Zr and 44.4 atomic pct Zr required annealing at 700 °C for complete recovery. The grains of both of these alloys were soft and rather ductile. Both Debye-Scherrer film patterns and spectrometer traces were made for each alloy using filtered copper radiation. Results and Discussion The presence of a substantial amount of second phase in an alloy with 1.1 atomic pct Zr indicated that the solid solubility of zirconium in nickel is somewhat less than 1 atomic pct. The a0 value for the face-centered-cubic matrix in the same alloy was equal to that of pure nickel, so that the solubility must be very small. This observation is as expected from the large atom size difference. Annealed specimens of alloys with 15.0, 16.7, 22.5, 28.6, 44.4, and 59.4 atomic pct Zr showed. micro-structures that were essentially single phase. When

Jan 1, 1958

By Howard Scott, Henry S. Rawdon

The method of demonstrating the structure existing in a metal or alloy at high temperatures, by etching a polished sample after it has been heated to the desired temperature, is quite familiar to metallog-raphists. The usual procedure1 2 is to heat the specimen, previously polished for microscopic examination, to the desired temperature, in a neutral atmosphere (hydrogen or nitrogen), then admit the etching gas (chlorine, hydrochloric acid or similar gas) for a few seconds, and finally, after flushing out the etching gas with the neutral one, cool the specimen in the neutral atmosphere. The pattern produced by etching at a definite temperature is usually taken as a record of the microstructure prevailing at that temperature. It has frequently been pointed out that changes in composition of the surface metal occur during the preliminary heating in the neutral atmosphere, so that the appearance produced by the etching at high temperature may not exactly represent the condition of the interior of the specimen. To overcome this uncertainty, the heating has sometimes been done in vacuo,3 the etching gas being admitted when the desired temperature was reached, then pumped out and the specimen cooled in vacuo. The studies of Rosenhain, Humfrey, and other workers 4, 5, 6, 7, 8 dem-

Jan 1, 1922

By Howard Scott, Henry S. Rawdon

The method of demonstrating the structure existing in a metal or alloy at high temperatures, by etching a polished sample after it has been heated to the desired temperature, is quite familiar to metallog-raphists. The usual procedure1 2 is to heat the specimen, previously polished for microscopic examination, to the desired temperature, in a neutral atmosphere (hydrogen or nitrogen), then admit the etching gas (chlorine, hydrochloric acid or similar gas) for a few seconds, and finally, after flushing out the etching gas with the neutral one, cool the specimen in the neutral atmosphere. The pattern produced by etching at a definite temperature is usually taken as a record of the microstructure prevailing at that temperature. It has frequently been pointed out that changes in composition of the surface metal occur during the preliminary heating in the neutral atmosphere, so that the appearance produced by the etching at high temperature may not exactly represent the condition of the interior of the specimen. To overcome this uncertainty, the heating has sometimes been done in vacuo,3 the etching gas being admitted when the desired temperature was reached, then pumped out and the specimen cooled in vacuo. The studies of Rosenhain, Humfrey, and other workers 4, 5, 6, 7, 8 dem-

Jan 1, 1922

By Fred E. Carter

AT first sight, the platinum group of metals seem of little import to we, the people," although actually the life of the common man is much influenced by them; this influence is usually indirect, hence his lack of knowledge and interest. He generally associates platinum with high-class jewelry and lets it go at that. Were 11e to go deeper, he would find that platinum metals play their part in his food supply, his clothing. his health, his transportation, his home. And the technical man is in general only slightly better informed, for he usually does not realize how necessary platinum metals are in the manufacture of the many construction materials and chemical products with which he is acquainted. Certainly, our daily lives would be profoundly affected if platinum were suddenly to become unavailable.

Jan 1, 1944

By W. R. Davison, C. A. Brown, J. P. Carstens

INTRODUCTION The phenomenon of heat-weakening of rock with 10.6 micron radiation from a continuous-wave C02 gas laser has been investigated in detail at the Massachusetts Institute of Technology for over 5 years. The programs at MIT have explored the basic nature of the heat-weakening phenomena and rock fracture caused by heating (e.g., Refs. 1 and 2), and have resulted in quantitative estimates of the relationship between the amount and parer level of heating and the resulting decrease in the modulus of rupture of a rock beam in a three-point bend test (Ref. 3). Results of the tests reported in Ref. 3 indicate a greater than 90% reduction in the modulus of rupture for granite beams heat-weakened by a laser. These results prompted the U. S. Department of Transportation to seek an assessment of the expected feasibility of employing the heat- weakening concept in a full-scale tunnel boring operation. Present- day continuous rock-tunneling machines have demonstrated tunneling time and cost savings over drill-and-blast methods, when used in rock types that are easily broken by the cutters. However, cutter bits have not yet been developed which can easily penetrate very hard rock

Jan 1, 1971

By Samuel Wyer

1. THE following is an abridgment of a recent report made by the author, covering an investigation of (A) The necessary use of natural-gas compressors; (B) The effect of gas compressors on natural-gas field operating conditions in Ohio, with special reference to the working pressure relations of gas wells of one company discharging by natural rock pressure flow without compressors, and adjacent wells of other companies, discharging into intake lines to gas-compressing stations. Tests were made at 107 different places in the counties of Fairfield, Licking and Knox, Ohio, which required 7,000 miles of automobile driving, and consumed 6 months' time. 2. A proper conception of. the necessary use and effect of natural-gas compressors in natural-gas production necessitates a clear understanding of certain fundamental definitions and judicial doctrines, which are given herein. 3. Gas is a fluid composed of a large number of molecules which are vehicles of energy continually in motion, and having an inherent. tendency to get farther and farther apart. The range of motion of the molecules is limited only by the volume of the closed containing vessel in which they constantly move to and fro. The most distinguishing characteristic of gas is its universal property of completely filling an inclosed space.

Jan 2, 1916

By Allan J. Clark

THE September issue of MINING AND METALLURGY might almost have served as a review of the advances in the metallurgy of gold during the current year. In addition to a scholarly article by F. W. Bradley, there were able descriptions by W. W. Bradley and W. F. Boericke of the methods followed in California and in Ontario. Considered together, the two last-named articles indicate the many possible combinations of flotation with one or more of the older processes. This, the prominence of flotation as an aid in the beneficiation of gold ores, is probably the most striking of the year's developments. It would perhaps be nearer the fact to say that the year has not been marked by the gold metallurgists' discovery of the flotation process, but rather by the flotation merchandizers' discovery of gold metallurgy. I say this because native gold was floated successfully more than fifteen years ago, and a reference to these results was published six years ago.

Jan 1, 1933

By Warren T. Smith

The Phelps Dodge Corp. Lavender pit is located in the Bisbee mining district near the town of Lowell, Ariz. A quartz monzonite porphyry exists as an intrusive stock and was the source of mineralization for the limestone replacement orebodies being mined by underground methods. Leaching of the upper portion of the stock, and precipitation of the copper as chalcocite on the finely dispersed un- oxidized pyrite in the monzonite porphyry, formed a low grade ore zone below a leached capping varying from 50 to 300 ft thick. Churn drilling starting in 1916 and supplemental churn drilling begun early in 1950 indicated a mineable area about 3100 ft long by 2400 ft wide. In general drilling was on 100-ft centers. The pit was planned with 50-ft benches and wall slopes varying from 1 to 1 to a flatter slope of 1 1/3 to 1 dependent on the character of the ground. Materials within the pit limits, using a 0.6 pct minimum grade cutoff, were estimated at 41 million tons of 1.14 pct copper ore, 31 million tons of low grade sulfides suitable for leaching with an average grade of 0.42 pct, and 70 million tons of waste.

May 1, 1956

By G. K. Burgess

§ 22. THe results published in Professor Howe's paper10 of our determinations on the Ac3 and Ar3 points for a series of commercial carbon steels " containing manganese in varying proportion, represent the average temperatures found by taking several (4 or 5) heating and cooling curves. The accompanying curves, Figs. 6 and 7, are, for each steel, the first heating and cooling curves as obtained by the inverse-rate method of Osmond, using a cylindrical chronograph sensitive to 0.1 sec. for recording time. Simultaneous observations were also taken by the differential method with a platinum neutral and plotted by Rosenhain's derived differential method and gave substantially the same results, the curves having sensibly the same contours in both cases.12 The observations were taken in vacuo on cylinders 5 by 1 in. in length bored to center with a 1/8-in. hole to receive porcelain insulated thermo-couple, and inclosed in an out- and in-glazed Berlin porcelain tube heated electrically by platinum foil wound on the tube. The vacuum was usually better than 0.1 mm. The heating and cooling of the furnace was automatically controlled by a salt-water rheostat with shaped electrodes, giving a uniform rate of heating and cooling.

Jan 1, 1914

By Ralph H. Sweetser

IN the recent world-wide deflation of commodity prices the coal industry, including both anthracite and bituminous coal, had reached a level where the actual delivered market prices received by the operators were usually less than the cost of production. Many steel companies and public utilities, operating their own "captive" mines, could have bought coal during the past three years for less money than the true cost of coal produced at their own properties. Competition within the coal industry itself was cruel to the point of profitless operation, and the competition of other forms of fuel was bearing heavily on the coal producers. They were thus forced into methods of production and utilization that they had hitherto ignored; there had been almost complete absence of any appreciation (by the bituminous operators especially) of the necessity of real research work in finding better methods of preparing coal for specific uses, and in finding new and profitable uses for different kinds and grades of coal.

Jan 1, 1933

By R. W. Hunt

The old plan was to increase every part of a rail much in the same proportion. But each part should be in proportion to what it ha.; to do. The head should be deep in proportion to tile amount. of traffic and the lowness of the rate of interest on its cost. The body need only he strong enough to carry the head after it is well worn down, and that deperlds on the weight of the machinery, and in the case of steel has little to do with the volume of traffic, except SO far as that affects weight of machinery. Ad on most railroad systems, the same niacliinery is used on main lines with heavy traffic, and bra11ct:es with light, I suggested in 1874 that each systern adopt the same body of rail for both, and make the head deeper on the main lines, shallower on the branches. This plan was adopted on the Pennsylvania Railroad. Bandberg seems to recognize this in his patterns of 1878. E. W. HUNT, TRoy, N. Y.: Again Dr. Dudley preaents to our cousideration a series of most carefully conductetl experiments, and ~llile I fully appreciate the labor and thought this work has cost him, I must still hesitate to accept his deductiono. This paper dilliirs from the previous one in that it denls esclrieively with the wearing qualitiei. of steel rails. Dr. Dudley gives his reason for this change in the following statement: " With the improvement in maintenance of way which has characterized the Pennsylvania Railroad during the last five or six yearn, the remova1 of rails from the track from the first two of these causes (i. e., broken and crushel), has, if I am right, quite notably diminished. This certainly is true with regard to broken rails. And if, as time advances, the number of crushed rails shall diminish, both because of the continued improvement in maintenance of way before referred to, and because, owing to improved and better methods at the steel works, there are fewer crushed rails caused by physical defects in the steel, the question of the wearing capacity of steel rails obviously becomes the allimportant one." Certainly the condition of the roadhd has much to do with mils brealring, crushing, and wearing. If the Pennsylvania and other railroads have done and are doing their part, Dr. Dudley oourteously admits that the steel works have performed part of theirs. But as far as I am informed, the formulas which they have used have been and are still quite wide of the one he continues to recommend. The rails which are not breaking or crushing to so great an extent as formerly, contain higher percentages of both carbon and manganese.

Jan 1, 1881