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By R. I. Jaffee, C. M. Craighead, G. A. Lenning

THERE has been considerable discussion among A metallurgists and others interested in the development of titanium alloys as to the nature of the fine line markings which appear in the microstruc-tures of unalloyed titanium and a titanium alloys. These markings have been variously called x phase, etching pits, and twins. Figs. 1 to 3 show typical examples of the line markings as they appear, respectively, in high purity iodide titanium, commercial purity titanium rod, and a high purity a alloy containing 0.2 pct N. The commercial purity titanium sample, shown in Fig. 2, contains both line markings and some spheroidal retained-ß phase. The ß phase seen in this micrograph should not be confused with the line marking, since it originates from the iron present as an impurity in the sponge metal. It will be noted that the line markings seem to have a definite orientation pattern with respect to the grains and in titanium noticeably resemble the precipitation occurring in artificially aged high purity Al-Cu alloys. This similarity led to the hypothesis that the line markings observed in titanium and a titanium alloys resulted from precipitation of some unknown phase. With the work of Hägg1 and McQuillan2 as background, there was little reason to suspect hydrogen of being responsible for the line markings. Hagg reported that up to 33 atomic pct H was soluble in a titanium, and McQuillan reported an a solubility of up to 8 atomic pct. Furthermore, McQuillan examined metallographically a 5.1 atomic pct H alloy quenched from 300°C and stated that the structure appeared to be a single-phase a solid solution. Line markings have been observed frequently and were first noted by Jaffee and Campbell3 in 1949. They did not observe them in vacuum-annealed titanium and a Ti-O and Ti-N alloys, but did observe them in Ti-H alloys containing 0.25, 0.5, and 1 atomic pct H. They stated that it was doubtful that the markings were a second phase based on hydrogen, because 1 atomic pct was far from the accepted solid solubility of hydrogen in titanium. Finlay, Resketo, and Vordahl,4 in 1950, concluded that the markings were a true second phase as a result of observations on their etching characteristics. Anderson5 Commenting on these markings in titanium was inclined to associate them with hydrogen, but was loath to call them titanium hydride, because of the reported high solubility of hydrogen. Work at Battelle Memorial Institute for the Navy Bureau of Aeronautics," done concurrently with the work described in this paper, provided information on the experiment converse to that described by Jaffee and Campbell in 1949. This work showed that the amount of line markings in unalloyed titanium could be decreased by vacuum annealing at elevated temperature. It was suggested that this was the result of removal of hydrogen; previously, the data of Jaffee and Campbell9 howed that the markings appeared when hydrogen was added. Recent work at Battelle for the Ordnance Corps, Department of the Army, which is described here, now establishes the identity of the markings as a titanium hydride phase. A sample of high-purity titanium rod 1/4 in. diam, 0.009±0.001 wt pct H (0.43 atomic pct), Fig. 1, was resistance heated in a 0.05 micron vacuum for 41/2 hr at 1500°C. During the early states of heating, the pressure increased to 150 microns, indicating that gases were being evolved. After cooling in vacuum, the iodide titanium rod was analyzed for hydrogen. Vacuum-fusion analysis showed 0.0006 ±0.0003 wt pct H (0.03 atomic pct) to be present.* Metallographic examination of the vacuum-annealed rod showed only a transformed ß structure. There was no evidence of fine line markings, Fig. 4. A section of this vacuum-annealed rod was cold rolled to 0.040 in. thick sheet and annealed for 1 hr

Jan 1, 1953

By W. R. McMillan, E. A. Gulbransen, K. F. Andrew

Annealed and electrolytically polished pure iron was oxidized between 650° and 850°C at oxygen pressures of 0.1 to 2 microns Hg. Electron optical studies showed that oxidation occurs discontinuously over the surface and orients crystallographically with the substructure of the metal grains. IN previous papers', " the authors described the formation of oxide films on high purity iron at norrnal pressures and at temperatures below 300°C. Electron optical studies showed that the oxide film consisted of many individual oxide crystallites having nearly random orientation on each metal grain. The size of the oxide crystallites depended upon the temperature and upon the extent of oxidation. In these studies the crystallite size varied from 250 to 1800Å. Recently, Bardolle and Benard3 studied the crystal habit of the oxide crystallites formed on Armco iron between 650" and 850°C in what might be defined as a "poor vacuum" atmosphere in which the pressure could be varied between 10-1 to 10-3 mm of Hg. Their results showed that, at 850°C and a vacuum of l0-2 to 10-3 mm of Hg, a few well oriented nuclei of oxide were formed on the metal grains. At pressures between l0-1 to 10-2 mm of Hg, many oriented nuclei of oxide were formed. At 750°C the metal surface was bright although an oxide was present. Unfortunately, the extent of oxidation, the oxygen pressure, and the influence of carbon in the metal were not determined, and it was, therefore, impossible to give a theoretical interpretation to the very beautiful light micrographs. Bardolle and Benard used the light microscope to determine the crystal habit of the oxide and X-ray diffraction to determine the orientation relationships. It was believed that the use of controlled amounts of oxidation at high temperature is an important method for the study of the initial stages of oxidation of metals at high temperatures. This paper presents the first results of an electron optical study of this problem for iron. Since the electron microscope and electron-diffraction methods using stripped oxide films and surface replicas yielded finer details of the crystal habit and structure of oxide film, these methods were used in this study. Two types of iron having different carbon contents were used: Puron and Armco* iron. A com- parison of the results for these materials made possible a study of the influence of the surface oxide-carbon reaction on the initial stages of oxidation. Before discussing the experimental results, the thermodynamic equilibria of 1—the oxidation reaction, 2—the surface oxide-carbon reaction, and 3—the solubility of oxygen in iron, will be considered. In addition, it is important to consider the kinetic-theory predictions on the rate of collision of oxygen with the iron surface. Thermodynamic and Kinetic-Theory Calculations Only one type of reaction is usually considered in the oxidation of iron at normal pressures at high temperatures: Fe(a) + 1/2O2(g) = FeO(s) 3Fe(a) + 2O2(g) = Fe3O4(s) 2Fe(a) +3/2O2(g) = a-Fe2O3(s). [11 However, two other reactions may occur: FeO(s) + C (solid solution in Fe) + Fe(a) + CO(g) [2] and Fe(a) + O2(g) e Fe(a) (solid solution of 0,). [ 3 ] In addition, iron will react with the higher oxide at certain temperatures to form FeO. For a complete interpretation of the oxidation of iron at low pres-

Jan 1, 1955

By K. C. Ten Brink, Allen D. Garrison

A rrevious paper1 reviewed some of the properties of clays and shales and presented some data on the nature of the gelling phenomenon. It included a brief discussion of origin of clays and shales, their composition, structure, retention of water, ionization, base exchange, and the nature of the gelling of water suspensions. Other publications of the Institute2-8 have discussed the properties of clays and their relations to drilling-fluid behavior and control. It is the purpose of this article to present some new data obtained and arranged in a different manner and making possible a better understanding of the chemical reactions involved in the control of drilling-fluid characteristics during the normal drilling operations. Experimental Procedure The difficulties involved in the measurements of the flow characteristics of plastic fluids are too familiar to recite. The possible applications of some of the well-known instruments to this problem have been adequately discussed by Hobson9 and he has given an excellent bibliography. Although there are many viscosimeters of varied design, none of them appear to fulfill the most obvious demands of accuracy in the measurement of clay or shale suspensions. Since the fluid characteristics are dependent on the rate of flow of the fluid, and the viscosity usually falls off very rapidly as the rate is increased, it is clear that the first requirement is that the instrument shall be capable of a wide variety of speeds. The viscosity of the fluid at any fixed and constant rate of flow is also a function of time, so that the second demand is that the instrument shall be capable of a constant and continuous motion for a prolonged period of time.

Jan 1, 1940

By K. C. Ten Brink, Allen D. Garrison

A rrevious paper1 reviewed some of the properties of clays and shales and presented some data on the nature of the gelling phenomenon. It included a brief discussion of origin of clays and shales, their composition, structure, retention of water, ionization, base exchange, and the nature of the gelling of water suspensions. Other publications of the Institute2-8 have discussed the properties of clays and their relations to drilling-fluid behavior and control. It is the purpose of this article to present some new data obtained and arranged in a different manner and making possible a better understanding of the chemical reactions involved in the control of drilling-fluid characteristics during the normal drilling operations. Experimental Procedure The difficulties involved in the measurements of the flow characteristics of plastic fluids are too familiar to recite. The possible applications of some of the well-known instruments to this problem have been adequately discussed by Hobson9 and he has given an excellent bibliography. Although there are many viscosimeters of varied design, none of them appear to fulfill the most obvious demands of accuracy in the measurement of clay or shale suspensions. Since the fluid characteristics are dependent on the rate of flow of the fluid, and the viscosity usually falls off very rapidly as the rate is increased, it is clear that the first requirement is that the instrument shall be capable of a wide variety of speeds. The viscosity of the fluid at any fixed and constant rate of flow is also a function of time, so that the second demand is that the instrument shall be capable of a constant and continuous motion for a prolonged period of time.

Jan 1, 1940

By R. J. Brison, W. C. Bleimeister

The International Salt Company has long been interested in finding an efficient process for the removal of impurities from rock salt, and particularly from the rock salt produced at the Detroit mine. Methods which have been used previously at the Detroit mine included both hand sorting and differential crushing in a Bradford breaker with rejection of the oversize. Neither of these methods was adequately effective. The development of a new process for removal of impurities from rock salt has been described in the preceding article." Basically, the process consists of exposure of crude rock salt to radiant heating which selectively heats the impure particles. Subsequently the heated particles are removed by adhesion to a heat sensitive-coating on a conveyor belt. This method was found to be effective in improving both the quality and appearance of rock salt by the rejection of the dark, impure particles.

Jan 8, 1960

In late May, at its final session in Nairobi, Kenya, the UN Conference on Trade and Development (UNCTAD) narrowly rejected the US proposal for a new International Resources Bank suggested by Secretary of State Henry Kissinger. The proposal was defeated by a roll-call vote of 33 to 31, with most of the nay votes cast by communist countries, and with 89 of the less-developed countries abstaining or absent.

Jan 7, 1976

By E. C. Bitzer

THE primary object of the work described in the following pages was to simplify the equipment in the separating circuit of the heavy-media process by substituting a spiral classifier for the separatory cone. Mechanical considerations were the leading attraction and the best that was hoped for on metallurgical performance was that the new vessel would give results equal to those obtained by conventional equipment. Tests have demonstrated in commercial operation on iron ore that the mechanical advantages of the spiral separator are about as predicted; also, the metallurgical performance is superior to the cone on the ores treated. Treatment of iron ore involves the separation of two products: a concentrate that sinks and a float product that contains true float material plus a controlled division of interfering middling. The middling material is heavier than the average specific gravity of the separating medium. Recent work with the spiral separator on Tri-State zinc ore showed that the middling material had to be recovered as concentrate because this fraction contained the bulk of the-zinc in the ore. It has been demonstrated that it is possible to make three products with the new separator on an ore such as this: a float tailing, a float middling, and a high grade heavy sink product. It appears from this last work that the new separator has definite mechanica1 and metallurgical advantages over any type of separating cone for treating feed that contains large amounts of material of a specific gravity close to that of the separating medium. However, either type of separator should perform equally well, metallurgically, on feed that is free of middlings. Each series of experiments with the spiral separator as required additional work to fully develop the possibilities of the machine. For this reason the paper is divided into chronological parts. History of Development A drag-type classifier was first proposed as a substitute for the cone separator by Butler Brothers technicians during the initial tests with galena medium at Crosby, Minn., in 1937. The desire for finding a substitute for the cone arose from trouble with interfering middlings and certain operating disadvantages of the cone. The possibility of using a spiral classifier was also suggested at this time by Emmett Butler and C. J. Abrams. However, inability to satisfactorily recover fine galena, which was used as a medium, terminated all development work at Crosby. During the winter of 1937--1938 investigation started on magnetic medium with concurrent s development of the inverted or closed- top cone, which was found necessary to eliminate iron-ore middlings with the float product. About

Jan 1, 1947

Scores of visitors who had never in their lives seen a piece of rough-and-ready mining machinery flocked around the display of Russian equipment presented as part of the Soviet Exhibition at New York's Coliseum. The Russian show, which ran from June 30 to August 10, presented an impressive view of an emerging technology. The exhibitors, however, made little attempt to appeal to the visitor who came only to be amused. In the mining show, as well as elsewhere throughout the exposition, the exhibits were devastatingly highbrow. If a coal mine's hydraulic roof support were "designed to support the prop- , free face front in longwall faces of flat seams, from 1.0 to 1.6 m thick, with medium-stable side rock," the visitors were told just that.

Jan 9, 1959

By A. W. McReynolds

One characteristic of plastic deformation which distinguishes it from elastic strain is the essential inhomo-geneity of plastic strains. Elastic strain varies continuously through a material, and average relative displacements of initially adjacent atoms are only small fractions of their initial spacing, (strains of the order of 0.01 or less). On the other hand, plastic flow corresponds to the appearance of discontinuities in strain of the lattice, such as dislocations or slip bands, where local strain, on an atomic scale, is several orders of magnitude higher. These discontinuities are visible on a microscopic scale as the familiar slip lines (Fig 1). In spite of this obvious microscopic inhomogeneity, however, macroscopic measurements almost invariably show a smooth curve of stress vs. strain (Fig 2b) even if measurements of linear strains be made to an accuracy of one part in 107. This macroscopic homogeneity of strain indicates that the discontinuities in strain on slip planes occur in increments too small or too slow to be recorded individually, and further that they occur sufficiently independent of one another so that the small increments add at random to a smooth stress-strain curve. The present paper describes observations of plastic strain in aluminum of commercial purity and in high purity Al-Cu alloys, where there exists a strong coupling between slip in various regions of the specimen such that once initiated it spreads rapidly through a large volume. The total effect is that of relatively large, rapid, and regularly spaced steps of strain followed by periods of only elastic strain. Fig 2a illustrates the type of "stair-step" stress-strain curve which results. The properties of this cooperative slip phenomenon will be described further in the section on results: in par- ticular it will be shown that each step corresponds to the propagation of a wave of plastic deformation through the specimen. Some interpretations of the mechanism by which it occurs will be made in the following section. Although the type of plastic wave phenomena to be described has not previously been reported, there are numerous cases of related effects in the plastic yielding of metals: YIELD POINT PHENOMENA The most familiar of such effects is the "yield point" observed in low carbon steels, brass, duralurninum, and the like. It consists in the sudden termination of the elastic portion of the stress-strain curve by a large plastic strain. Since the usual tensile machine is such that yielding of the specimen relieves the load, the resulting curve is as shown in Fig 3. As the strain continues, deformation occurs at a lower stress for some time, then follows a rising curve, but with no further sudden yielding. This effect has been observed in brass by Sachs and Shojil and later by many others. Edwards, Phillips and Jones2 made extensive studies of the effect in steel, and of the role of various alloying elements. Although there seems to be fairly clear evidence that the yield point is caused by a hardening of the material by precipitation of impurities, no satisfactory explanation for the sudden yielding has been given. Winlock and Leiter3 have shown that the strain. level of the upper yield point depends strongly on the rate of loading, the yield point increasing by almost a fac- tor of two as the strain rate goes from 0.002 in. per in. per min. to 4.4 in. per in. per min. This effect would seem to imply an incubation period before yielding is initiated at a certain stress. On the other hand, by going to very slow loading rates, Edwards, Phillips and Jones2 showed that the yield point does not become lower and eventually disappear as might be expected, but, on the contrary, begins to rise at loading rates below about 25 Ib per in. per min. becoming much higher than at rapid loading rates. STRAIN AGING If, instead of continuing straining of a specimen after occurrence of a yield point, the load is removed and the specimen aged, resumption of the test results in occurrence of another yield point as shown by the dotted curve of Fig 3. The new yield stress is generally higher than the previous maximum applied stress. This hardening of the material by straining and subsequent aging is undoubtedly related to quench age-hardening resulting from the aging of a specimen quenched from high temperature. Since neither effect is observed in pure metals, it is generally accepted that quench-aging in all cases is the result of hardening by precipitation of a supersaturated alloying element, and that strain-aging is probably a similar precipitation, accelerated by disruptions of the lattice by previous strain. Pfeil4 has shown that strain-aging does not occur in iron from which all of the carbon has been removed, but that only a very small carbon content, around 0.003 pct, is necessary to cause strain-aging. In accord with this observation is recent work by Dijkstra5 in this laboratory showing that the solubility limit of carbon in iron is extremely low, less than 0.001 pct at 400°C. Edwards, Phillips and Jones2 have shown that the strain-aging effect is also removed by the addition of small quantities of elements such as Mo, Mn, Ti, and the like, which readily form carbides. Their results demonstrate the

Jan 1, 1950

By C. H. Herty

The reactions that occur in the basic open-hearth process are complicated and are subject to many different factors such as temperature, slag composition and rate of boiling of the bath. It is difficult, therefore, to present an extended theoretical discussion of open-hearth operations without confusing the theory of the process with the application of the theory. This paper attempts to present some of the theory of the open-hearth process without mentioning theory at any point, simply giving some of the practical applications of results founded both on theory and practice and on experimental work both in small and large furnaces. It is hoped that an answer to a number of questions commonly asked by the open-hearth operator may be found in this paper. Discussion of the subject matter is taken up more or less in the order in which a heat ie worked, beginning with the oxidation of the scrap charged, sulfur absorption by the scrap, calcination of the limestone, and extending into the pig iron for the charge, the slags formed during the process, and some of the phenomena occurring in deoxidation of the steel and in its action in the molds. Oxidation of Scbap When scrap is charged into a furnace it immediately begins to oxidize, Oxidation is carried out by.three reactions: Fe + H20 + FeO + Hz (absorbs heat) (1) Fe + C02 + FeO + CO (absorbs heat) (2: Fe+ ½O2 + FeO (gives off heat) (3: The product of oxidation contains some Fe3O4, but FeO usually predominates on account of the iron present in close contact with the scale formed For a given type of scrap the amount of oxidation is controlled by thc fuel and by the excess air being carried in the furnace, the temperature 01 the furnace, and the length of time that the scrap is in contact with the furnace gases. In general, less oxidation occurs when the furnace is rur hot so that the scrap melts rapidly. More important in operation thar the two variables atmosphere and temperature, is the type of scrap being

Jan 1, 1929

By Leo Tarasov

MAGNETIC torque studies of ferromagnetic single crystals have been carried out in a number of laboratories during the last decade1,2 and some work has been reported on polycrystalline material showing preferred orientation. Goss3 used the method extensively in developing electrical sheet with desirable magnetic properties, but he used it as a control rather than as a means of studying the texture. Bozorth4 made a quantitative correlation of a torque curve he obtained from some cold-rolled iron with the texture as determined from X-rays, but did not extend his studies beyond the one specimen. Other studies, which have been reported from time to time 1.5 have also been incomplete in the sense that no effort was made to study a whole series of samples, differing only in degree of cold reduction, or in the annealing temperature, in order to ascertain the effect of such treatments on the texture as revealed by torque measurements. It is the purpose of this investigation to make such a study, mainly in order to see how useful the method can be made when used under favorable circumstances and to find what kind of a correlation can be expected between magnetic and X-ray studies of texture. Before proceeding further, it is desirable to say a little about single crystals, so as to make clear the concepts involved in magnetic torque measurements.

Jan 1, 1939

By John Brownson

Ge-Si N-N heterodiodes hare been built recently which show promise as high-speed logic devices. Low-resistivity germanium is deposited on silicon substrates held at temperatures above the germanium melting point and an alloyed heterojunction formed. The diodes are fabricated from this material using conventional mesa techniques. Over-all device qualify has been greatly improved by the use of epitaxial silicon substrates, that is, a subsirale consisting of a film of thin, high -resistivity silicon on a thicker Piece of low-resistirily silicon crystal. A semimpirical device design equation has been devised which predicts switching performance fairly well within the range of resistivitics and geometries employed. Switching times 01 0.9 ns and PIV 's of —20 v are typical of the better 10-ma diodes. Switching times as low as 0.5 ns have been observed for 10-ma diodes and as low as 2.8 ns for 200-ma diodes. With further development it should be possible to improve switching speed by a factor of four. IN our laboratory, Ge-Si heterodiodes have been built recently which show promise as high-speed logic devices. The diodes have been built using a process reported in some detail in an earlier publication.' The process in short involves alloying a thin film of low-resistivity germanium into a silicon substrate. the germanium having been transported and deposited by the well-known Theuerer halide reduction process.2 This process contrasts with that reported earlier by Oldham who used an essentially conventional direct epitaxial deposition technique.3 Oldham's process, unlike ours, requires cleavage of the silicon sample inside the reactor furnace the instant prior to deposition. Our process has the advantage of yielding large-area macro-scopically plane heterojunctions. Heterodiodes in general have several interesting properties. Without attempting to summarize the theory of heterojunctions.4 two of these properties which have direct relevance should be mentioned. First, N-.V and P-P heterojunction diodes rectify alternating current. Provided that either the band gap or the electron affinity of the two materials is different (which in general is the case), electronic barriers will exist in the junction band structure. When the device is sufficiently forward-biased, the barriers shift so as to permit current flow, and when it is reverse-biased. the barriers block current flow. Second, for N-N and P-P heterodiodes. the foward-conduction process involves majority carriers only. Consequently. when such a device is turned off. there is no minority-carrier storage and hence the diodes switch on and off quite rapidly. As we have reported earlier. N-P and N-N Ge-Si heterodiodes have been built in this laboratory. As one would predict from theory, the N-P heterodiodes were rather slow in turning off while the N-N's were quite fast. Similarly, the turn-off time of the N-P's increased rapidly with forward current while that of the N-N's was independent of forward current. Both N-N's and N-P's were moderately photosensitive. Photocurrents resulting from normal room illumination were as high as 1 µa at 1 v for small-area devices. The most disappointing parameter of the early N-N devices was reverse leakage.' The reverse characteristic was invariably "soft" and leakage at only several volts reverse bias was intolerable. The reverse characteristic was greatly improved by using higher-resistivity silicon substrates. Leakage becomes large at voltages about one third of the avalanche voltage one would expect of a P-N homo-junction formed on silicon of the same resistivity. Thus leakage could be reduced to reasonable limits by using unconventionally high-resistivity silicon. Medium-power diodes formed on 30 ohm-cm substrates leaked typically 15 to 50 µa at 100 v reverse bias. The use of high-resistivity silicon substrate material, however, created a new problem. In order to have an acceptable forward-conductance characteristic. the area of the diodes had to be increased. With this increase in area, the capacitance increased. Switching time for N-N heterodiodes is essentially a linear function of capacitance. Thus when the resistivity was raised. so was the switching time. A SEMIEMPIRICAL HETERODIODE DESIGN EQUATION As a result of our experiments with a limited range of diode geometries and resistivities. a semi-

Jan 1, 1965

By Robert S. Moehlman

Is recent years, exploration and development by diamond drilling has become a popular attack on the problem of finding new ore shoots and developing extensions of known shoots. Diamond drilling has been used in recent years in extensive sampling of disseminated copper deposits, in preference to churn drilling. At the Harvard gold mine, near Jamestown, California, Philip R. Bradley, Jr., general superintendent, reports that: "The Harvard work was a singular example of the reliance that can be placed on diamond drilling in evaluating an ore body." Drilling at the Harvard mine will be discussed in a subsequent section of the paper. So popular has diamond drilling become, indeed, that many who have had slight experience with drilling are inclined to regard it as a cheap cure-all. This paper proposes to show some of the limitations on the application of drilling and some of the steps that should be followed in drilling programs to obtain reliable results. Cost oF Drilling Drilling has the advantage, over shaft sinking and drifting, of lower cost and greater speed. As compared with churn drilling, the advantage of bringing up a coherent sample instead of fine cuttings for a sample is obvious. Diamond drilling is generally more expensive, however, and more engineering effort is required in combining the average of core and sludge samples. Exploration of drift walls by hammer drills to a depth of less than 30 ft. is generally cheaper than diamond drilling, but beyond this depth the diamond drill is cheaper and more efficient. The principal factor in determining cost of drilling is the character of the ground drilled. Broken ground with many fissures is most expensive to drill. Hard ground is less of a problem with diamond drills than with ordinary machine drills. Hardness or softness affects only the speed of drilling. Caving, easily washed, sandy or clayey ground requires continual cementing and casing, which is the greatest cost problem. Thus, soft, incompetent ground is more costly to drill than hard, massive ground. Cost of drilling per foot in good to fair ground varies from less than $I per foot, achieved in some districts in Ontario, the Mother Lode, and Missouri, to $5 per foot in many western states. In bad drilling ground, costs may range from $5 to $15 or more per foot, thus approaching the cost of drifting. Other factors that increase the cost per foot are: I. Short total length of hole drilled, so that the cost of moving in crews and equipment must be spread over a relatively few feet. 2. Cost of drilling per foot increases with depth beyond about 500 ft.. as more time is consumed in pulling rods' 3. Cost of preparing drilling stations, getting air underground to stations? etc' 4. Inaccessibility and lack of water on the job make for higher costs.

Jan 1, 1946

By Philip S. Mathews

THE tremendous stimulus given to the mining industry by the gold and silver policy of the present administration has found the capital market for mines ill prepared to afford practical means of financing. Particularly has this been true of the host of abandoned high-cost producers and prospects which increased gold and silver prices have made potentially profitable. In a comparatively short time, experience has demonstrated abundantly that valuable properties have frequently failed to secure capital, while questionable properties have drawn to themselves and their promoters more of the public moneys than their prospects justify. Singularly enough the fault is usually attributable to faulty financing. Discussion and study of this problem are vital to the industry.

Jan 1, 1936

By P. R. Swann, R. M. Fisher, W. R. Duff

Observations by transmission electron microscoPy of the microstructures in quenched Fe-A1 alloys provide the basis for revision of the Fe-A1 phase diagram. The diagram is characterized by first-order transitions between the disordered ferromagnetic a! solid solution and the two ordered phases FeAl and Fe3Al. However, second-order transitions showing corre-luted fluctuations in the degree of order near the critical temperature occur between the paramagnetic a! and FeAl and the FeAl and FeAl phases. ELUCIDATION of the true nature of the Fe-A1 equilibrium diagram has proven to be an extremely challenging problem as evidenced by the fact that six quite different versions of the iron-rich portions have been published since 1958.&apos;-6 The most recent diagram shown in Fig. 1 was proposed by Rimlinger6 based on X-ray diffraction analysis and dilatometry. He shows the single-phase fields of the ordered phases of the types FeAl(L20) and Fe3A1(D03) and the disordered bcc Fe-A1 solid solution, a, separated from one another in every case by large two-phase regions. Thus, he implies that in Fe-A1 alloys ordering always occurs via a classical phase transition. In contrast to this view, theoretical studies3&apos;" have concluded that the transitions a — FeAl and FeAl — Fe3A1 should be second- or higher-order in character. A further revision of the Fe-A1 diagram of state is presented in Fig. 2 based on our previous8,9 and current observations by transmission electron microscopy of the microstructures found in quenched specimens. The average quenching rate was 50,000°C per sec and although this was sufficiently rapid to prevent Fe3A1-type ordering below -550°C it was not sufficient to suppress ordering of the type FeAl in the temperature range -650" to 800°C. However, ordering during the quench is easily recognized since the FeAl phase formed during holding at temperature rapidly develops large antiphase domains whereas FeAl formed during quenching has a very fine domain size, -50Å diam. Each symbol in Fig. 2 indicates the result of a micro-structural examination of specimens heat-treated (-1 hr) until equilibrium was established. The results will be discussed in the order of the points, A - Dl marked on both diagrams with reference to the phase fields, critical temperature, and "transition" ranges, respectively. The dark-field micrograph corresponding to point A is shown in Fig. 3 and was obtained using a 111 reflection of the Fe3A1 structure which reveals both a&apos;/4<111> and a&apos;/2<100> antiphase domain boundaries.10 The structure observed in this specimen is typical of single-phase Fe3A1 and shows no evidence for FeAl or any other additional phase. The dark-field micrograph shown in Fig. 4 corresponds to point B on the two diagrams. It was taken with a 100 FeAl reflection which reveals a/2(111) domains and exhibits the typical structure of single-

Jan 1, 1970

By E. G. Leonardon, C. Schlumberger, M. Schlumberger

Last year the authors presented a paper that discussed the various electrical measurements they perform in drill holes, which they name "electrical coring."&apos; The object of the present paper is to give a brief account of the points of scientific interest that have been elucidated by further field work and laboratory research, as well as the economic results that have been attained recently. The practical examples given in this paper are drawn, for the most part, from the field work performed in Russian oil fields during the years 1931 and 1932. This is due to the fact that, thanks to the comprehensive cooperation of the Russian geologists and scientists, the authors are allowed to make public a large amount of recant information. In other countries in which the authors are engaged in similar work, the competition between private companies makes it imperative, for a considerable lapse of time, to avoid publication of the results obtained. The following points will be discussed successively, under separate headings: 1. Electrochemical phenomena in drill holes. 2. Stratigraphic correlations and tectonic studies. 3. Relations&apos; between the productivity of oil horizons and their electrical resistivity. 4. Location of coal seams. 5. Summary and conclusions. Electrochemical Phenomena in Drill Holes Technical Publication 462l described the author&apos;s discovery concerning the existence of important differences of potential spontaneously gener-

Jan 1, 1934

By O. C. Holbrook, George G. Bernard

A new theoretical treatment has been obtained for the behavior of pattern waterflood injection wells when closed in. Two cases are treated: Case I where oil and water are assumed to have the same properties, and Case 2 where they arc different. In applying the method, one plots log (p — p,) vs closed-in time, where p is well-bore pressure at any tims and p, is static pressure. The value of p. is determined by trial and error as that value which makes the plot linear at large time. A value for the permeability-thickness product can be determined from the intercept of this linear part, and a value of the skin factor from the injection pressure at time of closing in. Application of the method to data from water floods at three fields seems to give reasonable results. For the case of unit mobility ratio, it is proved that this new method should give the same value for permeability-thickness product as the conventional pressure build-up method. In addition, the new method gives correct values for static pressure, whereas the conventional method does not, often indicating negative static pressures. The new method may be used in cases where the surface pressure persists after closing in as well as in cases where it does not. INTRODUCTION It is of considerable interest and importance to be able to determine the characteristics of the reservoir in an area surrounding a water injection well. Thus, if we can determine early in the life of an injection well that there is a considerable "skin effect", remedial measures can be started before a full-scale pattern flood begins. Similarly, if it can be shown that a gradual buildup of skin effect is occurring with time, measures to free the water of plugging material can be taken. Determination of static pressure in the water-injection well may show that the water is entering a thief zone and not the desired reservoir. Finally, determination of the permeability of the sand around the injection well will allow estimation of the future relation between injection pressure and rate. It should be possible to determine average reservoir permeability, skin effect and static pressure from pressure fall-off data. However, at the time we began work on this subject, it was thought that no adequate theory on which to base such determinations&apos; was available. According to the conventional method which considers the reservoir to be filled with one fluid of small compressibility (see Van Everdingen, Joers2, and Nowak2), shut-in pressure is plotted vs log where is injection time, and At is closed-in time. The physical significance of injection time, may well be questioned in this case, since in a reservoir completely filled with a single fluid (as required by this theory) and with input and output rates equal, the pressure behavior after an initial transient is independent of t,. Attempts by our Tulsa area to use this theory led to negative values of static pressure in most cases. Because of these limitations of the method discussed above, it was decided to attempt to develop a new theory of pressure behavior in water injection wells, one which would apply when there is a gas saturation, as is so often the case in water floods. In the following treatment the assumptions and basic equations are given first, then the method of application of the equations. A complete example is given to clarify details of application. All difficult mathematics has been placed in the appendices so that the reader can follow the text without difficulty. However, if he wishes only to apply the results without knowing the basis for them, he can learn how to do this from reading only the sections entitled "Plotting of Experimental Results" and "Example." ASSUMPTIONS AND BASIC EQUATIONS Statement of Problem It will be assumed that a horizontal layer of constant thickness contains in its pore system a mixture of oil, gas and water. While water is being injected into this pore- system through a well at constant rate, an oil bank is built up, gas being expelled from the space taken by the oil as shown in Fig. 1. The saturations within each

By J. F. Peters

The term solution loss is discussed and defined. Examples are given showing that solution loss may either have a favorable or unfavorable effect on blast furnace performance. A theory is advanced explaining the contradictions encountered during earlier studies of the problem. MANY papers have been written and numerous theories advanced concerning the chemical reactions in the iron blast furnace. Richards, discussing the utilization of fuel in the blast furnace, said: "All the carbon burnt in the furnace should be first oxidized at the tuyeres to CO and all the reduction of oxides above the tuyeres should be caused by CO, which thus becomes CO,. This dictum is not Gruner&apos;s own words, but expresses their sense, and from the point of view of the present discussion, it is the correct principle upon which to obtain the maximum generation of heat in the furnace from a given weight of fuel." Richards also said the cubic feet of wind per pound of coke does not express how efficiently a furnace is running, but it will be shown later where Howland paid much attention to this figure. Richards pointed out a shortcoming of Grun-er&apos;s discussion in that Richards claimed there is not enough CO generated in a good working blast furnace to possibly combine with the oxygen of the ore, so some of it must be reduced by solid carbon. Mathesius2 made two important contributions. First, he wrote the direct and indirect reduction equations showing the heats of formation in each case and stressed that the indirect reduction reaction produces heat while direct reduction absorbs heat. Secondly, he substantiated Richards&apos; conclusion that there may be a deficiency of CO gas and that some direct reduction is required, but he pointed out that "direct reduction in the hearth has often been confused with direct reduction in the stack, which more correctly should be termed &apos;premature combustion&apos;." Then he said that "as this carbon is consumed partly by economical (direct reduction in the hearth) and partly by wasteful reactions in ever varying proportions, it is evident that the relation of this total carbon gasified above the tuyeres to the fuel consumption of a furnace cannot possibly have a direct bearing on the economy of furnace operation. The premature combustion of carbon (CO2+C?2CO) must therefore in all cases be considered a detrimental reaction." Johnson3 discussed this whole problem. Through experience Johnson found that when departure from Gruner&apos;s ideal working is considerable, the fuel economy is poor, and when the quantity of blast goes up, the fuel economy goes up in the same proportion. Johnson said that the wind per pound of coke is a measure of fuel economy, which will be shown to be wrong. Howland4 established the fact from operating data that there was no relationship between the coke consumption of a furnace and the percentage of coke burned at the tuyeres. But some of his calculations have led to questionable conclusions, such as "it is practically impossible to obtain low coke consumption unless we keep our wind low." Howland made an important contribution when, in his concluding paragraphs, he reached certain negative decisions as to why one coke works better than another. He said the reason one coke works better than another in a blast furnace is not because: 1—there is any difference in the percentage gasified at the tuyeres, or 2—there is any difference of wind required per pound of coke. Korevaar5 propounded a new theory on combustion which disagrees with Gruner because "as far as we can see, this is sufficient proof for the invalidity of Gruner&apos;s ideal, for if it was valid, the Low coke consumption should always be accompanied by a higher percentage of carbon burned at the tuyeres. This not being the case, we must deliberately give up our belief in Gruner&apos;s ideal." The part in italics will be proved to be wrong. Martin" contended that there was not enough reducing capacity in the blast furnace unless solution loss occurs. He came to a series of conclusions, such as: 1—The greatest efficiency of the blast furnace may not be attained when the reduction is performed entirely by carbon monoxide as demanded by Gruner&apos;s definition of the ideally perfect working of the blast furnace. 2—The so-called solution loss reactions, which should more properly be termed direct reduction reactions, promote furnace efficiency. 3—In modern blast furnace practice, the carbon consumption of the process is determined primarily by the carbon needed for reduction purposes, any thermal deficiency created by the reduction process being balanced in practice by the use of blast heat. From a practical standpoint further discussion of the theory of chemical reactions is of little moment. There is however one phase of the general theory of chemical reactions which is very important and that is the combustion of coke in the blast furnace. The purpose of this paper is to show that the reaction

Jan 1, 1955

Alexander N. Winchell, Butte, Mont. (communication to the Secretary): Mr. Spurr calls attention to the fact that an ore-deposit may be due to a succession of concentrations at different geological epochs. He cites an example of such a condition on Napoleon creek, a branch of Forty-Mile creek, Alaska. It will perhaps be of interest to call attention to another example of the same general character, not so remotely situated. The example referred to is located on Pole creek, a tributary of Cherry creek, in the extreme northeastern part of Madison county, Montana. An excellent geological map of this region is to be found in the Three Forks folio (No. 24) of the United States Geological Survey. According to this map, Pole creek, in its upper course, occupies the contact between the " Flathead " formation, which Peale correlates with the Middle and Lower Cambrian, and an area of gneisses and schists supposed

Jan 1, 1903

By William Y. Holland, Roger H. Cook

Dexter H. Reynolds (Chapman and Wood, Mining Engineers and Consulting Geologists, Albuquerque, N. M.)—A number of questions are raised by conclusions and inferences made in the above-mentioned paper. The more troublesome of these concern use of the various pozzolans to combat the deleterious effects of the alkali-aggregate reaction. The most alkali-reactive materials listed are opal and rocks containing opaline silica. The pozzolans mentioned specifically for use as amelioratives are opaline shales and cherts. These are stated to retard the expansion caused by the alkali-aggregate reaction. Another well-recognized pozzolan is diatomaceous earth, which consists principally of opaline silica. A pozzolan presumably owes its effectiveness to its high reactivity with the alkaline liquid phase of the concrete mix. It appears reasonable to expect that finely divided opaline silica added as a pozzolan would be more susceptible to reaction with the alkalies present than would larger particles of the same material. The authors report that work with high and low alkali cements indicates that in the presence of alkali-reactive materials, deleterious expansion depends upon the alkali content of the cement. The total effect, therefore, should be more or less independent of the amount of reactive aggregate present, and still more independent of its state of subdivision. The deleterious effects should, if anything, be aggravated by the addition of a finely divided, highly reactive pozzolan. Further, if the alkali-aggregate reaction is of great importance in the long-term soundness of concrete structures, the addition of a pozzolan to a concrete made with aggregate free from known deleterious materials would be a questionable procedure. The benefits reportedly accruing from such use of pozzolans are greater ultimate strength for a given cement content, increased resistance to deterioration by exposure to sulphate solutions and other mineral waters, and greater resistance to damage by wetting and drying and freezing and thawing. In view of the deleterious effects of highly reactive materials are these benefits ephemeral? The same considerations apply to another alkali-reactive material, chalcedony, which appears to consist of ultrafine-grained quartz, with opal absent in detectable amounts. Quartz flour is notably reactive chemically and physiologically (cf. Ref. 11 of Holland and Cook&apos;s paper), a fact borne out by its effectiveness as a pozzolan, which presumably might be expected to offset the deleterious effects of the presence of chalcedony in the aggregate. A second question of some importance concerns the reportedly highly deleterious reactivity of acidic and intermediate volcanic glasses, such as rhyolite, perlite, and pumice. Air entrainment is listed as one of the ameliorative measures to combat the deleterious effects of the alkali-aggregate reaction. The alkalic-silica gel formed by the reaction may expand into air bubbles and thus not cause appreciable expansion of the concrete mass. It would appear then that pumice and perlite, particularly perlites of the pumiceous types and other types after expansion, would also tend to counteract the expansion, since these materials consist largely of voids and air bubbles. Certainly this would be expected of structural concrete in which pumice or perlite is used as total aggregate. Finely ground pumice, perlite, and volcanic ash have been demonstrated to be active pozzolans (cf. Pumice as Aggregate for Lightweight Structural Concrete by Wagner, Gay, and Reynolds, Univ. of New Mexico Publications in Engineering No. 5, Albuquerque, 1950). In fact, the term pozzolan was first associated with finely divided pumice or volcanic ash. Such materials were used with hydrated lime as the sole cementitious agent in constructing public buildings, roads, and aqueducts by the ancient Romans. The deleterious alkali reactivity of the volcanic glass, itself containing several percent of the alkalies, apparently did not contribute to the remarkable state of preservation of those ancient structures, as exemplified by the Appian Way and the Pantheon Dome. Still a third question involves .the reactivity of constituents of concrete when exposed to various salt solutions. Resistance to. deleterious expansion and cracking as a result of contact with mineral waters and its relationship to the mineral content of the aggregate are not mentioned by the authors. Yet the phenomena pictured in Fig. 1, and especially in Fig. 2, appear very much like those caused by exposure to mineral waters. The deterioration of concretes exposed to sulphate waters is generally considered related to the chemical constituency of the cement itself, particularly to the relative amount of tricalcium alum-inate contained. Could not many of the ill effects presently blamed on alkali-aggregate reaction really have been caused by contact with sulphate or other salt-containing mineral waters? Or perhaps their use as mixing waters? May not the deleterious expansion be as much a function of the chemical makeup of the cement as it is of the mineral constituency of the aggregate? Would it not be just as important to use alkali-free mixing water as it is to use a low-alkali cement? It appears obvious that resistance of cements and concretes to sulphate and other salt solutions cannot be left out of account in discussion of deterioration of concrete structures with time. This factor may be of equal or even greater importance than the alkali-aggregate reaction, particularly for concrete subjected to wetting and drying cycles, such as airstrip paving, water-retaining dams, and highway structures. Another very important factor is called to attention on page 1022 of the article in Mining Engineering, October 1953, in that failure of concrete structures may result from poor construction practices and use of too high water-cement ratios. Both of these can contribute remarkably to decreased resistance to attack by sulphate waters, and presumably could have an equally remarkable effect upon extent of damage resulting from the alkali-aggregate reaction. From the above remarks it appears that while alkali-aggregate reaction may be an important factor in decreasing the useful. life of a concrete structure, it is not the only factor involved, and it may not be even a controlling factor. Likewise, many of the phenomena apparently associated with the alkali-aggregate reaction may have resulted from cond&apos;itions which had little relationship to the alkali-reactivity of a constituent of the aggregate. Certainly if alkali-aggregate reactivity is a major factor in bringing about early failure, one cannot help feeling anxiety concerning the future of the many concrete structures in this country and abroad in which pumice and perlite were used as total or partial aggregates. This anxiety can only be dispelled by calling to mind that among the best-preserved relics coming down to us from ancient times are structures made with mortars containing highly alkali-reactive aggregates.

Jan 1, 1955