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By D. L. Gardner, H. L. Barr

THE following report covers the history of the development of the mine, present equipment, methods and costs of mining and milling. In addition, a description of the ore deposit is given with emphasis on the origin of the fractures, mode and types of ore occurrence, and mechanics of granite emplacement. An endeavor has been made to present a complete and accurate statement of the San Mauricio mine, the highest grade gold mine in the Philippine Islands. Credit is gratefully acknowledged to the mine staff for descriptions and details regarding their particular field of work. All analyses were made by Mr. T. A. DeVore, head chemist, San Mauricio Mining Co. Messrs. Edward Wisser, J. E. Fyfe, A. F. Skerl and W. B. Meek, geologists, have contributed geologic information and ideas, for which thanks are extended. The Executive Committee of Marsman and Co., Inc., Managers of the Company, has kindly given permission for publication. Mr. J. B. Stapler, Division Manager, Marsman and Co., has had the courtesy to read the manuscript and to give critical and helpful suggestions. LOCATION OF AREA AND SCOPE OF WORK San Mauricio Mining Co. controls a group of 113 claims that lie immediately north of the town of Jose Pañganiban (formerly Mambulao), Camarines Norte, Luzon, P. I. (Fig. 1). Exploration work commenced in the spring of 1934; active development began in the fall of that year and has continued to the present date. Mill construction was begun Oct. 15, 1935, and production started March 10, 1936. Total production to June 1, 1939, is P10,499,105.15 ($5,249,552.57). [+]

Jan 1, 1940

By G. H. Billings

The following data were collected some years since in the course of a series of experiments with oil as a substitute for coal in puddling, the earlier form of the Archer apparatus being employed. While I am not at liberty to give the name of the works at which the tests were made, I can personally warrant the accuracy of the record, and feel justified, therefore, in making this contribution to a discussion in which all trustworthy figures are likely to be helpful. Oil in Puddling. Starting with everything cold, we used 3518 pounds of oil to get the furnace in condition to charge a heat. After charging, we ran until we took out 13,340 pounds of puddled-blooms, using 8437 pounds, or 1333 gal1ons of oil. At 49 cents per gallon, the cost for oil per gross ton of blooms was $10.91; with coal at $4.871/2, and a consumption of 1.5 tons per ton of blooms (the usual quantity is ton for ton), the cost for coal is $7.31. The quantity of oil consumed in heating the furnace to the proper temperature and to make the bottom, is not included in the oil consumption stated. The quantity used was 3518 pounds of oil. Usually, the furnace need only be lighted, but in this case it had been repaired, and it was necessary to make a new .bottom. This required the quantity of oil necessary to make three heats of blooms, or 2109 pounds. Deducting this from the 3518 pounds leaves 1409 pounds of oil as the quantity consumed every week in lighting up.

Jan 1, 1889

PRESIDENT BENJAMIN B. THAYER,2 NEW YORK, N. Y. PAST PRESIDENTS JAMES F. KEMP,1 NEW YORK, N. Y. CHARLES F. RAND,2 NEW YORK, N. Y. FIRST VICE-PRESIDENT SIDNEY J. JENNINGS; NEW.-YORK, N. Y. TREASURER ' GEORGE C. STONE,1 .NEW YORK, N. Y. SECRETARY EMERITUS ROSSITER W. RAYMOND, NEW YORK, N. Y. SECRETARY BRADLEY STOUGHTON NEW YORK, N. Y.

Jan 8, 1914

By Nicholas J. Grant, Michio Yamazaki

Cast copper alloys containing 10, 20, and 30 pct Ni and 0.75 to 0.80 pct Al were machine-milled into chips, then comminuted in a rod mill to fine flake powder utilizing a number of processing variables. The powders here internally oxidized, mostly at 800°C, in a low-pressure oxygen atmosphere. The consolidated powders were hot-extruded into bar stock. Room-tenmperature tension tests, stress-rupture tests mostly at 650°C, but also at 450° and 850°C, and hardness measurements after various annealing temperature treatments to study alloy stability were perfomted. Excellent room-temperature strength, high rupture strength at 650°C, and resistance to recrystallization at 1050°C were obtained. Problems in optimizing conditions for internal oxidation of Cu-Ni base alloys are discussed. THE interesting high-temperature properties of SAP' have stimulated considerable effort in the study of more refractory alloy systems where the potential for high-strength alloys at high temperature is great.2-13 A number of methods have been utilized to produce the desired fine, hard particle dispersions, of which internal oxidation2,9,7 of dilute solid-solution systems offers considerable promise by virtue of the potential for producing ultrafine, well-dispersed oxides. While most of the published works are concerned with pure metal matrices, a number of investigators have studied the effects of solid-solution strengthening.10,19 Use of more complex alloy matrices (for example, aging systems) has been unsuccessful because overaging still occurs at high temperatures in the oxide-containing alloys.14.15 Solid-solution strengthening is, however, effective at very high temperatures9,10 and might be expected to contribute importantly to the strength of oxide-dispersion strengthened alloys. For this study, internal oxidation of solid-solution alloys of copper and nickel, containing small amounts of aluminum, was chosen as the method of alloy preparation. PREPARATION OF ALLOYS Three copper alloys containing about 10, 20, and 30 pct Ni and each containing 0.75 to 0.80 pct A1 (enough to yield about 3.5 vol pct alumina) were prepared as air-cast ingots measuring 2.5 in. diameter by 6 in. high (see Table I for the analyses). Processing steps for all the alloys were as follows (also see Table 11): 1) Homogenization of the ingot at 982°C (1800°F) for 45 hr in an argon atmosphere. 2) Machine milling of ingots into fine chips. Average thickness was about 0.1 to 0.2 mm. 3) Hydrogen reduction of chips at 593°C (1100° F) for 1 hr to reduce copper and nickel oxides. 4) Rod milling of chips to finer powders. 5) Hydrogen treatment of powders as in step 3. 6) Internal oxidation of the powders. 7) Hydrogen treatment of oxidized powders as in step 3. 8) Hydrostatic compression of evacuated powders. 9) Sintering of compacts in hydrogen. 10) Hot extrusion. Variations in processing among the alloys were made in steps 4, 5, and 10 (see Table 11). In the past, two methods were utilized to internally oxidize alloy powders. Preston and Grant3 surface-oxidized dilute Cu-Al powders to obtain the necessary amount of oxygen to oxidize the solute metal (aluminum and silicon), and then permitted the formed copper oxide to diffuse and react with the solute in an argon atmosphere. Bonis and Grant4 exposed Ni-A1 and other nickel alloys to an oxygen pressure derived from the decomposition of nickel oxide at a preselected temperature, in an argon atmosphere. Both methods are applicable and can be modified to generate a range of oxygen pressures for oxidation of the solute but not the solvent metals. Procedure I: Surface Oxidation of Alloy A3, Cu-10Ni-0.76A1. Powders of -20 to +28 mesh were surface-oxidized at 500°C (932°F) to obtain the desired amount of oxygen for oxidation of the aluminum to alumina; the powder was then sealed in Vycor and heated at 900°C (1652°F) for various times up to

Jan 1, 1965

By C. E. Sims

IN an earlier paper by Sims, Moore, and Williams: data were given to show that hydrogen contents of 0.3 relative volume (0.00033 wt pct), existing at the center of 4-in.-square cast-steel coupons, could be removed by aging at 400°F for 125 hr. At the end of that time, complete restoration of normal ductility for the steel was obtained. Replicate specimens of the same steel were aged at room temperature up to 555 days or .18 1/2 months. At the end of that time, the hydrogen content at the center had fallen to 0.13 relative volume or 0.00015 wt pet, but there was no perceptible change in the ductility. On the basis of experience with accelerated aging of 1-in. and 4-in. coupons and room temperature aging of 1-in. coupons, it was predicted that, some time after two years and when the hydrogen content has been reduced to about 0.10 relative volume, there would be some recovery of ductility. One set of three bars remained, and these were held for 1310 days, or more than three years. Then tensile test bars were cut from the center, and these bars were sampled for hydrogen analysis at the time they were broken. The sample specimens were cylinders % in. in diam x 1 1/4 in. in length. The data showed that in this time the average hydrogen content had fallen to 0.096 relative volume or 0.00011 wt pct, and the ductility had increased sharply. Elongation had risen from 10 to 17.3 pct, while reduction of area increased from about 16 to 27.5 pct. On the basis of these data, fig. 1 was drawn to replace fig. 15 of the earlier paper. Extrapolation of the curves of fig. 1 indicates that it would require a period of about 2200 days or approximately six years at room tem- perature to reduce the hydrogen to the minimum value and to recover full ductility in the center of the coupons. The aging process apparently involves the movement of hydrogen from the interior to the surface of the bar and evaporation at the surface. This flux of gas presumably follows some diffusion mechanism, and an effort was made to use the aging data, obtained at room temperature and at 400°F, to calcu-late coefficients of diffusion, in the hope that they might indicate the nature of the diffusion. The conclusion was reached. however. that the data were inadequate for such a purpose.

Jan 1, 1951

By B. J. Bayles, J. A. Ford, M. J. Salkind

Unidirecltonally sulidijied AL-A13Ni was found to exliibit excellent microstructural stability to 508°C. Above this temperature the transverse micvostructure coarsened in a manner analogous to "Ostwald Ripening", but the A13Ni whiskers did not spheroidize or foreshorlen. The coarsened whiskers reinforced the matrix as effectirely as the finer whiskevs and no reduction in room-temperature tensile strength mas noled after exposure for 90 hr at 96 pel 0-1 the absollite melling temperature of the eulectic. The slability was auribucted to the presence of low-index (and presurrlably lor-energy) cvystallographic interjaces between phases. The driving force for microstructural coursening was presumed to be the reduction of interfacial energy between the phases. Finer micvoslructures were found to coarsen more rapidly than those which weve imitally coarser. FIBER-reinforced metals have been shown to exhibit good short-time tensile properties at elevated temperatures.1-4 However, many elevated-temperature applications require long-time property retention which dictates the necessity for microstructural stability. Two types of instability are common to fiber composities. The first, chemical instability, is due to chemical reaction between the matrix and the relnforcing phase. Petrasek and weeton5 have shown that chemical reaction between tungsten wire and several copper alloy matrices resulted in degradation of the reinforcing phase and reduction in strength of the composite materials. Kreider and Leverant4 have noted similar behavior for boron-reinforced aluminum above 400°C. The second type of instability arises in systems in which the phases are essentially chemically stable with respect to each other and is characterized by spheroidization and/or agglomeration of the reinforcing phase. parratt6 has reported this type of degradation to occur relatively rapidly at moderate temperatures for nickel and cobalt alloys containing whiskers of silicon nitride, aluminum oxide, and silicon carbide and has identified it as "physicochemical" instability. Although both types of instability are the result of the differences in the chemical potential between the fibrous phase and the matrix, they may be differentiated by the fact that the second type, "physicochemi-call' instability, results in little or no net change in the composition or amount of each phase present. It does, however, result in a morphological change which profoundly affects the strengthening mechanism. Chemical interaction. on the other hand, results in a change in the composition and amount of one or more of the phases present, or the appearance of a new phase. In the latter case, the appearance of the mi-crostructure, that of a fibrous phase aligned in a matrix, may remain essentially unchanged, but the chemical degradation of the fiber results in markedly reduced composite strength. This investigation was initiated in an attempt to evaluate the microstructural and related mechanical property changes of a whisker-reinforced eutectic composite after elevated-temperature exposure. The composite system chosen for this study was the uni-directionally solidified A1-A13Ni eutectic which Lemkey. Hertzberg, and Ford7,8 demonstrated to behave as a whisker-reinforced composite. The microstructure of the unidirectionally solidified material consists of aligned needles of A13Ni in a matrix of aluminum. EXPERIMENTAL PROCEDURE Eutectic ingots having a nominal composition of 6.2 wt pct Ni were produced by melting 99.99+ pct A1 and 99.99 pct Ni in recrystallized alumina crucibles in an argon atmosphere. The analyses of the starting materials are listed in Table I. These master heats were cut up? melted by induction heating, and unidirectionally solidified vertically in 1/2 -in.-ID. 6-in.-long graphite crucibles, in a dynamic argon atmosphere. Therma1 gradients in the liquid were determined by measuring the temperature in the melt as a function of apparatus travel distance, as discussed by Kraft and Albright.9 The rate of solidification was assumed to be equal to the uniform rate at which the crucible assembly was withdrawn from the furnace. Ingots representative of nominal growth rates of 2, 5, and 11 cm per hr were produced and the solidification parameters are summarized in Table 11. Ingots used for met allographic analysis were pre-

Jan 1, 1968

By K. M. Rolls, J. Wulff, D. A. Colling

Solid-solution alloys of the Ta- Ti system containing up to 70 at. pct Ti were melted and fabricated into wire. Steady magnetic-field measurements of cold-worked wires at 4.2°K indicate that the resistive critical field increases smoothly with increasing titanium, reaching a maximum of 93 kG (J = 1 amp per sq cm) for a composition of about 50 at. pct Ti. The composition dependence of the resistive critical field indicates it is largely paramagnetically limited for alloys containing more than 35 at. pct Ti. For cold-worked wires the value of the critical current density, Jc , was found to be insensitive to composition changes for compositions in excess of 20 at. pct Ti. It was observed that Jc could be increased by final-size heat treatment at 400°C without altering the value of- the resistive critical field. Experimental data are used to calculate the electronic specific-heat coefficient and the "upper critical field" for the alloys studied. THE effect and importance of metallurgical structure on superconducting properties have been summarized by Livingston and Schadler.1 Specific work on solid-solution alloys such as Nb-zr2-7 and Nb-Ti5-7 have shown that critical current density (Jc) and superconducting transition temperature are structure-sensitive. Berlincourt et al.6,8,9 in their studies of transition-metal alloys find that Ta-Ti alloys remain superconducting at fields comparable to Nb-Ti alloys. 6,8 Transverse critical current tests of a Ta-10 at. pct Ti alloy10 and longitudinal critical current tests of a Ta-25 at. pct Ti alloy1' indicate that such alloys are capable of carrying high currents at intermediate fields (-40 kG). The work reported in the present paper was undertaken to explore the superconducting properties of further compositions in the Ta-Ti alloy system as well as the structure sensitivity of the superconducting properties. I) EXPERIMENTAL PROCEDURE Alloys were prepared by melting tantalum (Fansteel Metallurgical Corp., 99.96 pct purity) and iodide, crystal bar titanium (Foote Mineral Co., 99.92 pct purity) mixtures in an arc furnace on a water-cooled copper hearth using a tungsten electrode. Melting was accomplished in a purified, gettered argon atmosphere at pressures from 250 to 400 Torr. Each alloy was turned and remelted fourteen times to assure complete mixing of tantalum and titanium. Ex- cessive coring in the cast samples was, nevertheless, observed. This was somewhat reduced by annealing in vacuo at 1000°C for 13 hr. The ingots were then machined to 0.250 in. diam, jacketed in Type 304 stainless-steel tubing, and swaged to 0.140 in. diam. They were then drawn to 0.010-in.-diam wire. Alloys containing up to 70 at. pct Ti were readily cold-drawn to wire in this manner. Later experiments showed that oxygen additions up to -3000 ppm could also be cold-worked into wire. Test samples for superconductivity measurements in the 2-in, air-core Bitter solenoids of the M.I.T. National Magnet Laboratory were prepared from 10-in. lengths of 0.010-in.-diam wire, cleaned of residual wire-drawing lubricant. Current contacts were made by clamping clean copper tubing over both No. 18 current lead wire and the ultrasonically indium-tinned ends of the specimen wire.12 Potential leads of No. 32 copper wire were connected to the specimen by ultrasonic soldering in an indium bath. The potential lead separation was about 4 cm, corresponding to the circumference of the Bakelite rod to which the wire was affixed with half-mil Teflon tape. The final specimen configuration is shown in Fig. 1. Specimens were lowered into a liquid helium bath (4.2oK) in a double solenoid dewar and positioned so that the maximum magnetic field was oriented transverse to the wire axis of the gage section. Measurements were made by passing a current through the specimen at a preset solenoidal magnetic field. The current was increased until a 1-pv potential difference appeared across the gage section (1/4 µv per cm). At low magnetic fields, however, it was not possible to use this criterion because power-dissipation difficul-

Jan 1, 1967

By R. G. Wheeler, J. W. Goffard

The Larson-Miller parameter was used to correlate time, temperature, and indentation creep of magnesium, aluminum, and some of their alloys. In the temperature range 300" to 450°C, the short-time Meyer hardness of pure magnesium was less than that of the magnesium alloys tested, but for long times the pure magnesium has greater indentation creep resistance. Aluminum (1100 alloy) had 1.5 to 2.5 times more indentation creep resistance than magnesium at 300" and 450oC, respectively. Hardening of aluminum with a dispersion of Al2O3 was effective in the time and temperature ranges studied. New technologies have required the development of new materials and the utilization of the more familiar materials for new and unusual applications. The use of magnesium and aluminum and some of their alloys, because of their desirable nuclear characteristics, light weight, low cost, and ready availability, has been extended to the 300" to 450°C temperature range. In this temperature range the basic consideration of these materials must be their rate of plastic flow rather than offset yield strengths. The indentation testing reported here arose from a need for design data for the load-holding ability of supports made of these materials. Test Procedure—Hardness indents were made with a 0.275-in.-diam quartz indentor and a 10.65-lb load. The indentor was made by fire-polishing a spherical surface on the end of a fused quartz rod. The samples were held at temperature in a graphite crucible controlled to ±2°C. A thermocouple was attached to the sample and test temperatures were recorded. The diameter of the spherical indentation was measured at the end of a test period and the compression stress (Meyer Hardness) was determined by: H___________load__________ m = projected area of indent Samples were 1 in. in diam and at least 1/4 in. thick. It was observed that at the higher temperatures and longer times, the quartz indentor would stick to the magnesium sample. The quartz indentor was, therefore, frequently inspected and fire-polishing repeated when necessary. The area of sticking was always a small fraction of the area of indent and was therefore considered to have an insignificant effect on results. Correlation of Hot-Indentation Test Data with Time-Temperature Parameter—Sherby and Dorn' have correlated creep or tensile data of a' solid solutions of aluminum with a temperature and strain-rate parameter suggested by Zener and Holloman. underwood2 used this parameter to correlate creep properties of some steels with hot hardness, and upon the basis of this correlation a means of obtaining creep properties from short-time (and inexpensive) hot hardness tests has been demonstrated. Since the validity of the correlation of creep properties with a time-temperature parameter and the correlation of creep properties with hot hardness have been shown, it follows that hot hardness may correlate with the time-temperature parameter. The hot-indentation data obtained was expressed as Meyer hardness, and was shown to be time and temperature dependent. Correlation of Meyer hardness, time, and temperature with the parameter was made using the relationship: Hm = Meyer hardness t = time, hours T = absolute temperature, OK K = constant A value for the constant K was calculated by equating In l/t + K/T at different temperatures and times but at the same hardness. The correlation was tested by plotting Hm vs the parameter, In 1/t +K/T. Since materials are being sought which have high hardness at low indentation creep, i.e., a high Meyer hardness for long time at high temperatures, low values of the parameter are ofthe most interest. TEST RESULTS Magnesium—Pure magnesium (99.98 pct) cut from extruded rod was indentation tested perpendicular to the rod axis at temperatures of 300°, 350°, 400°, and 450°C for times ranging from 6 sec to 112 hr. Fig. 1 shows the time dependency of Meyer hardness at the four constant temperatures. Fig. 2 shows the correlation of the Meyer hardness of pure magnesium with the time-temperature parameter using a K of 22,720 in Eq. [I]. At the bottom of Fig. 2, the effect of doubling the time of indentation t2 = 2(t1), on the abscissa for any time is shown graphically. This effect is of constant magnitude. Also shown graphically are the magnitudes of the effects on the

Jan 1, 1960

By L. J. Gurevich

IN the course of the examination, at the Bureau of Standards, of fusible tin boiler plugs for the Steamboat Inspection Service, it became evident that an investigation should be undertaken to determine the precautions necessary in the manufacture of acceptable plugs. The results of the tests of these plugs show that their manufacture has improved, though at present not all of the plugs tested are satisfactory. Table 1 gives the result of tests of some 1500 plugs from about 100 makers. Records of the tests show that several of the makers were able to produce satisfactory plugs with every pouring. The Steamboat Inspection Service has the following specifications for fusible plugs: "Fusible plugs for use in boilers of steam vessels under the Jurisdiction of the Steamboat Inspection Service shall be made of bronze casing with the bore tapering continuously and openly from end to end, and filled from end to end with tin not less than 99.7 per cent. pure and to contain not more than 0.1 per cent. of lead and not more than 0.1 per cent. of zinc. The small end of the bore may be countersunk not more than 1/32 in. in depth and width, but no recess, thread, or cavity other than this countersink shall be allowed."

Jan 8, 1919

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 W. Evans, C. E. Ells

The agglomeration of hydrogen in pure aluminum and A1-Mg alloys has been studied through use of hydrogen introduced into the metal by cyclotron proton irradiation. Both the growth and dispersal of the agglomerates have been followed by metal-lographic techniques. During the cyclotron irradiation, agglomeration occurs at temperatures i 100°C for hydrogen concentrations as low as 1 ppm. On heating at elevated temperatures, 300°C to 600°C, intragranular agglomerates first coarsen and then disperse. The agglomerates formed at grain boundaries are much larger than the intragranular agglomerates; with hydrogen concentra- tions > 10 PPm, heating for 1 hr at 500°C results in extensive grain-boundary cracking. The hydrogen agglomerates have been shown to inhibit grain growth, but no inhibition of recrystallization has been observed. The ability of hydrogen to enter aluminum at a free surface, combined with its high-diffusion rate at elevated temperatures, accounts both for growth and dispersal of the agglomerates. Irradiations at elevated temperatures give results consistent with the explanation proposed for agglomerate behavior on post-irradiation heating. 1 HE formation of hydrogen-filled bubbles, or blisters. in aluminum and its alloys has been studied for over' thirty years. The work up to 1952 has been reviewed by Kostron' and since then Ransley and

Jan 1, 1963

By R. Schuhmann, G. W. Powell

The concept of local equilibrium is examined and, in particular, the applicability of the concept to two-phase binary diffusion couples is discussed. It is concluded that, if binary solid solutions are treated thermodynamically as ternary solutions, vacancies being the third component, then recent experimental observations of nonequilibrium interface compositions (i.e., compositions different from the phase diagram values) are consistent with a state of complete dynamic equilibrium at the interface. CLASSICAL approaches to diffusion and to other irreversible processes often utilize a postulate of "local equilibrium". That is, one assumes even in the presence of gradients, fluxes, and time changes of properties, a) that the Second Law can be formulated locally, and b) that thermodynamic equations of state among intensive properties are identical with those for equilibrium phases. A direct consequence of this assumption, for example, is that one would calculate the total entropy of a nonequilibrium phase simply by integrating the entropy density (eu per unit volume) over the volume of the phase, assuming that entropy density is the same function of energy and particle density as for equilibrium phases. In the study of diffusion and of diffusion-controlled phase transformations, metallurgists take this concept of local equilibrium for granted and utilize it automatically. In fact, experimental evidence of all kinds is overwhelming that "local equilibrium" is a valid limiting law, approached more and more closely as gradients and rates of change approach zero. On the other hand, we have neither experimental nor statistical thermodynamic proof that this principle of "local equilibrium" should remain rigorously valid at high gradients and for rapid processes. Theoretically, in fact, one would expect deviations because interactions between adjacent volume increments of material affect the evaluation of entropy. Also one observes experimentally structural and small energetic differences between equilibrium and nonequilibrium phases. The purpose of this paper is to present a thermodynamic framework for the study and correlation of deviations from strict local equilibrium in isothermal diffusion and related processes. This procedure, in effect, preserves the principle of local equilibrium by thermodynamically assigning the deviations from static equilibrium properties to a defect component. Although this theory is entirely phenomenological, the possibility does exist of correlating the theory with experimental observations of defects under favorable circumstances. The most immediate application appears to be to the equilibria at the interfaces in two-phase binary diffusion couples. A recent pertinent work by Eifert et al.1 has shown that the concentrations of aluminum in the a(fcc) and B(bcc) phases at the 0-8 interface in Cu:Cu-12.5 wt pct A1 diffusion couples are greater than those given by the phase diagram. It is postulated by these authors that the supersaturation of the o phase at the interface provides the driving force for the a-to-B lattice transformation; the excess free energy of the a phase, ?Gaxs, arising from the greater-than-equilibrium aluminum concentration is about 3 cal per g-atom. On the basis of the schematic free energy-composition diagram shown in Fig. 1, Eifert et al. concluded that the thermodynamic situation at the interface is one of the partial equilibrium; that is, = for the more mobile aluminum whereas will be reexamined in the latter part of this paper. THERMODYNAMIC PROPERTIES OF DEFECTS A rigorous analysis of the thermodynamics of defects requires an added degree of freedom in the Phase Rule sense, because the standard formulations of solution thermodynamics (partial molal properties of components, free energy minimization, equality of chemical potentials, and so forth) involve the implicit

Jan 1, 1970

By F. von Gemmingen, E. J. Fasiska, L. Zwell

EARLIER studies of the dependence of creep on structure1 and of the dependence of creep rupture on creep behavior2 did not include detailed discussion of the phases present in the specimens under examination. It is of interest to determine the nature and amounts of such phases present since it is well known that these are dependent on composition, heat treatment and creep conditions.3 This investigation has therefore been undertaken to identify these constituents and to determine their relative amounts. This report presents the results of this investigation and describes an improved "extraction replica" technique developed in the course of the work. The composition of the Type 316 austenitic stainless steels studied in this investigation is given in Table I. The specimens were solution treated at 2000°F for 1/2 hr and water quenched. Those specimens subjected to prestrain at room temperature Methods for extracting precipitate particles from materials for electron and X-ray diffraction analysis have been described by Fisher,4 Smith and Nutting: and Booker and coworkers.6'7 Electrolytic extraction methods have been described by Andrews and Hughes.8 The first two methods have been used at this Laboratory, but have not proved satisfactory for many problems requiring X-ray diffraction analysis. It has been difficult to remove the replicas or to avoid tearing them during removal. These difficulties are overcome by backing the replica with a water-soluble plastic such as Dupont 51-05 Elvanol (polyvinyl alcohol). The backing increases the thickness of the replica so that it can be mechanically stripped from unloosened particles without folding or tearing. This procedure eliminates the stripping of wet replicas, which usually have a low tear strength. By stripping replicas after drying, it is possible to extract partially loosened particles which otherwise would remain imbedded in the metal. The modified method is as follows: after the specimen is polished, it is etched for 60 min in modified glyceregia consisting of 30 ml glycerol, 7 ml nitric acid, and 4 ml of hydrochloric acid. The sample is then washed, air dried, and coated with a 20 pct Baker and Adamson 1611 collodion (85 pct amyl acetate by volume) film. After the collodion film is dry (about 15 min), the sample is again etched in the modified glyceregia for 50 min, washed with isopropyl alcohol (to prevent dissolving the collodion) and air dried. A very thick coat of polyvinyl alcohol (about 50 pct solution "Elvanol Dupont 51-05" in water) is poured over the sample and is permitted to dry for about 24 hr. The composite film containing the precipitates is then stripped from the specimen and floated, polyvinyl alcohol side down, in water (at about 50°C) until the polyvinyl alcohol dissolves. This usually takes about 15 min. Should any of the polyvinyl alcohol remain on the replica, it does not give a crystalline diffraction pattern and therefore does not hinder identification of the precipitates. The extraction replica, floating in water, is picked up on a glass fiber and mounted in the Debye-Scherrer camera for X-ray diffraction analysis. Concentration of the etchant, and also etching time, had to be increased for several of the samples. Fig. 1 shows two extraction replicas taken from different areas of spec. M74-37; X-ray analysis showed a strong diffraction pattern of M23C6 and a medium one of u phase. A

Jan 1, 1962

By Philip R. Strand, O. F. Stewart

Vermiculite is the name generally applied to the group of hydrated ferromagnesian aluminum silicates that are characterized by the ability to expand when heated. This process, called exfoliation, results in a lightweight product of commercial value. Most uses of vermiculite are for the expanded material. The chief markets are in construction, agriculture, and horticulture, with lesser uses in general industry. Composition and Properties Vermiculite, in its natural state, has the characteristic micaceous habit, a perfect basal cleavage which causes splitting into thin laminae that are soft, pliable, and inelastic. The structure of vermiculite is basically that of a talc. The prominent monoclinic crystal faces are often marked by lines at 60° and 120°. Hardness varies from 1.5 to 2 or more; specific gravities are between 2.1 and 2.8; color varies from almost clear to amber, bronze, brown, green, or black. Vermiculite feels like talc, especially when wet. Although much research has been performed on the chemical and structural composition, there is not yet complete agreement on the exact formula. This is to be expected when different workers have examined the many different varieties. Vermiculite is not considered to be a single mineral species but a family of related minerals. The structural formula for a trioctahedral vermiculite may be written: (H20)-(Mg,Ca,K)-(A12,Fe,Mg)-(Si,A1,Fe)4O10 (OH) 2 Hydrobiotite also occurs with vermiculite and is usually considered a vermiculite for commercial uses. When heated quickly to elevated temperatures, vermiculite expands by exfoliating at right angles to the cleavage into wormlike particles. The name vermiculite is derived from the Latin vermiculare, to breed worms. This characteristic of expansion is the result of the mechanical separation of the layers by the rapid conversion of contained water to steam. The decrease in bulk density of commercial grades is usually approximately 10 times, from 50 to 5 lb/ft3, but varies depending on the quality, size, and furnace efficiency. Individual flakes may expand up to 30 times. Vermiculite may also be expanded by soaking in chemicals such as hydrogen peroxide, weak acids, and other electrolytes. Color change during expansion is dependent upon the type of vermiculite and furnace conditions. Heating in an oxidizing atmosphere produces a dull gray or tan color, whereas a reducing atmosphere can produce a bronze or gold color. The expansion of the vermiculite crystal results in large pores being formed between the platelets. Thus, exfoliation makes available a large increase in void volume which is important in the application of vermiculite as a chemical carrier. Mathieson and Walker (1954) state vermiculite must be regarded as a true clay mineral. The characteristic properties of the mineral, such as high cation exchange capacity, organic complexing ability, and variable interlamellar distance are very similar to those of montmorillonite. The cation exchange capacity of vermiculite is one of the highest of all the clay minerals. The interplatelet space is accessible to penetration by some electrostatically neutral molecules. Water and glycerine are two common substances whose molecules may be so imbibed. In the natural state and under normal atmospheric conditions, water occupies the spaces between the silicate layers. The crystal d-spacing is near 14.2A. By differential thermal analysis, it has been determined that the water

Jan 1, 1983

THE strike and dip of bedded formations is readily determined by trigonometry if some marker horizon is intercepted by three holes. If no marker can be identified and if orientation of the cores is unknown, as is the usual case in diamond drilling, the determination still can be made readily by the use of a stereonet if the bearing, inclination, and angle the bedding makes with the core axis is known for each of the three holes. Such determination, valid only if the bedding orientation is fairly uniform within the area drilled, is considered simpler, faster, and more effective than any solution previously published. Method: The steps of this procedure are as follows: 1) Mark north and south poles on tracing paper placed over stereonet.* 2) Plot the three diamond drillholes by drawing a line from the center of the net in the direction of the bearings of the holes. Then rotate the paper until each line, in turn, lies along the equatorial diameter of the net; the end of each line is determined by the inclination of the hole measured in degrees from the periphery toward the center of the net along the equatorial diameter. Fig. 1 illustrates a vertical hole and a hole inclined at —23" due east. 3) With the projection of one diamond drillhole along the equatorial diameter, measure from the end of the hole, to the east and then to the west, a dis- tance in degrees equal to the core axis-bedding plane angle. Find two more points by measuring the same number of degrees north then south along the great circle from the end of the drillhole. Draw a circle, the center somewhere along the direction of the projection of the drillhole, to connect these four points. Draw circles for the other two diamond drillholes in the same manner. See Fig. 1 for two circles representing core axis-bedding plane angles of 35" and 23" and Fig. 2 for these plus a third circle representing a core axis-bedding angle of 42" in a hole bearing S 50 W inclined at —52". 4) Rotate the tracing paper until one great circle on the stereonet is found which is tangent to all three of the circles or parts of circles derived in the previous step. Trace this great circle on the paper and join its ends with a straight line passing through the center of the net. The bearing of this line is the strike of the bedding. In Fig. 2 the bedding strikes N 77 E. 5) Rotate the paper until the strike is along the polar diameter of the net. The dip of the bedding is determined by measuring along the equatorial diameter the distance in degrees from the periphery of the net to the great circle derived in step 4. The dip of plane illustrated in Fig. 2 is 55" to the N 13 W. Fig. 3 indicates the solution for three holes whose bearings and inclinations are N 20 W and —43o, due E and —30°, S 30 W and 23" with core axis-bedding angles of 30°, 50°, and 43" respectively. The bedding (stippled area) strikes N 44 W and dips 70" to the southwest.

Jan 1, 1956

By F. R. Hensel

THE demand for clean steel is increasing daily. New processes of refining steel are being developed in order to remove all nonmetallic inclusions as completely as possible, as it is the general opinion that. inclusions affect the dynamic properties of steel and iron to such an extent as to justify great expense for their removal. It is surprising to note at the same time the commercial development of a new process for making artificial wrought iron. By this process slag and steel are thoroughly mixed, the amount of nonmetallic inclusions usually exceeding 2 per cent in weight. The contradiction in these two efforts is obvious and is responsible for the investigation reported in this paper. H. W. Gillett also has recently emphasized the need for further research on wrought iron.1

Jan 1, 1932

By James R. Evans

Forecasting demand is an art as well as a science, and much personal judgment is required. National forecasts made for sand and gravel, crushed stone, and/or aggregate may be misleading or unhelpful locally. This is because of significant variation in demand within different geographic and/or political areas in the US, and/or the use of an inadequate data base and forecasting methodology. The best forecasts may be made for local or regional market areas, irrespective of geographic or political boundaries, provided a proper data base is available.1 The Bureau of Mines compiles detailed statistics on commodities sold or used in the construction industries and, therefore, is in an advantageous position to make national aggregate demand forecasts. Definitions of some terms used in this presentation are necessary before proceeding.

Jan 1, 1980

By H. N. Thomson

(Butte Meeting, August, 1913.) GENERAL. THE Tooele plant. off the International Smelting & Refining Co. is situated at the mouth of Pine canyon, Tooele county, Utah. It is connected with the main line of the San Pedro, Los Angeles & Salt Lake railroad by the Tooele Valley. railway, and is about 7 miles from Tooele Junction. Fig,. 1 is a general view of the plant. The copper plant has been in operation since July, 1910, and the first blast furnace it the lead plant was blown in on Feb. 29, 1912. The location of the plant was selected on sloping ground with the idea of using gravity to the fullest extent and thus keeping labor at a minimum. Practically the entire plant is constructed of steel, reinforced concrete, and. brick.

Jan 7, 1913

By W. C. Knopf, G. Samsel

For several years International Minerals & Chemical Corp. has used a radiation method to assay potassium content of products from potash and feldspar beneficiation. The procedure is rapid, accurate, and inexpensive and is easily handled, if necessary, by nontechnical personnel. Data are presented to show the accuracies that may be expected if the technique is used for control of pilot plants or large- scale plants. Natural potassium is composed of three isotopes -K39, K40 and K41. Five other isotopes, artificially produced, have been detected. In natural potassium only the K40 isotope, with a half life of 1.4 x 109 years, is radioactive. Its modes of decay are beta and gamma rays, positrons, and x-rays. Only the more abundant beta rays, however, are important in radiation measurements using geiger tubes.

Jan 10, 1958

By Oscar Lee

RESERVE Mining Co., owned jointly, by Armco Steel Corp. and Republic Steel Corp., controls 9% miles of magnetic taconite ore on the eastern end of the Mesabi Range lying between Mesaba and Birch Lake. The ore reserve which can be mined by open pit methods is conservatively estimated at 1.5 billion tons under a shallow, loose overburden requiring no rock stripping. Taconite now being mined is in the upper cherty horizon. It has been metamorphosed by the intrusion of gabbro and most of the iron oxide is altered to magnetite. The nonmagnetic portion of the iron is practically all in the form of silicate. The magnetic iron is finely disseminated through the rock and requires grinding -150 mesh for clean liberation of the iron oxide from the gangue.

Jan 5, 1954