Search Documents

By J. D. Sullivan, Chester R. Austin, J. L. Nunes

IT is characteristic of most shales and surface clays that a bloated or vesicular structure is produced by burning to a sufficiently high temperature, usually about 150° to 200°F. above the normal maturing temperature used when making common brick of the same material. Early investigators recognized this phenomenon and attributed it to the release or expansion of gases in the vitrified piece. A number of theories have been advanced on the source of the gas and the manner in which it is evolved, but none has been proved conclusively. T. E. Jackson's1 early theory that bloating was due to oxygen evolved by ferric oxide in forming ferrous oxide or ferrous silicate was never substantiated by experimental work. Orton2 thought this explanation unlikely, as all clays should bloat at the same temperature, if this were true. He found that clays bloated in the range from 1100° to I700°C. Also, many clays containing iron did not bloat at all, but fused. Orton also stated that oxidation of different types of carbon was a source of gas during burning of clay and should be expelled before vitrification was reached. Seger3 said that he had dissolved ferric oxide in glass with no apparent evolution of gas. Matson4 came to the conclusion that ferruginous clays burned to vitrification in an oxidizing atmosphere did not have the iron in a ferrous form. According to Wilson,5 the gases responsible for bloating might be entrapped air, water, sulphur dioxide, carbon monoxide, oxygen, and hydrocarbons. He spoke of two causes of bloating: (I) incomplete oxidation below the vitrification temperature, and (2) decomposition of compounds and evolution of gases above the vitrification temperature. Decomposition of calcium sulphate was given as the principal example of the latter. Bleininger and Montgomery6 stated that if any time after vitrification began the evolution of gaseous matter was rapid enough so that pressure was produced within the clay, bloating was certain to take place, and a vesicular structure would be formed. They recognized that initial structure, rate of heating, kiln atmosphere, and many other variables affected bloating. Work done by the Emergency Fleet Corporation7 indicated that clays suitable for bloating should be high in compounds of metallic oxides, carbon, sulphur, sodium, potassium, or other equivalent compounds, which either act as a flux or give off gas. Orton2 studied the chemical status of the carbon, iron, and sulphur in clays during various stages of burning, using a Huron shale that bloated under oxidizing or reducing conditions. He found that only a small amount of sulphur remained in the clay and that it could be detected only by dissolving the clay in hydrofluoric acid,i.e., the sulphur was in combination with the silica. Orton said that this sulphur was probably in the form of iron sulphide dissolved in the glass phase. The iron sulphide was not broken down by heating, but was dissolved in the basic slag or glass,

Jan 1, 1942

By V. R. Garfias

EVEN before the arrival of Cortes in 1519, the history of Mexico was closely linked to that of its mineral production; the mining activities of the Aztecs being thus described by Clavigero, one of the early historians: In the mountains of Anahuac there abound in veins all kinds of metals, and infinite variety of other fossiliferous products. The Aztecs obtained gold from the countries of the Cohuijques, of the Mixtecas, of the Zapotecas and from various other places. They gathered that precious metal usually in grain, from the sands of the rivers, keeping a certain portion for the crown. They obtained silver from the mines of Taxco, of Tzumpango and others; however, this metal was not as esteemed by them as by other neighboring nations. They had two kinds of copper; one hard, which they used instead of iron to make sickles, lances and all kinds of rural and military instruments and another, soft, with which they made kettles, goblets and other receptacles. This metal abounds mainly in the province of Zacatula and in that of Cohuijques, which at present is in the kingdom of Michoacan. They obtained tin from the mines of Taxco and lead from those of Izmiquilpan, located in the country of the Otomiea. From the tin they made money, and the lead, we know they sold in the market places, but we ignore the uses to which they applied it. They also had mines of iron in Tlaxcala, in Taxco and in other places; but they either had not discovered them, or did not know how to make use of the metal they contained. In Chilapa there were mines of mercury, and in other places there were mines of sulphur, alum, vitriol, cinnabar, cohre and of a white earth which they esteemed highly. As regards mercury and vitriol, we do not know of what use they were to them; the other metals they used in paintings and dyes. There were then great abundance of amber and asphalt-bitu- men of Judea--on the coast of the seas and many cities of that territory paid tribute of one and the other to the kingdom of Mexico. They mounted the amber in gold, and it was only used as ornament and display by them. With the asphalt they made certain perfumes. The following extracts dealing with pre-Colonial gold are taken from the famous "Cartas de Relación" to Charles V, in which Cortea described the progress of the Conquest: . . . here there came two chiefs who owned lands in the valley; one four leagues down the valley and the other two leagues up the valley and they gave me some gold necklaces of little value and seven or eight girls. . . . . . . that day I left the City of Churultecal and traveled four leagues to some villages of the City of Cuasucingo where the natives received me very well and gave me women and pieces of gold. . . .

Jan 1, 1937

Discussion of the papers of FREDERICH LAIST and HAROLD W. ALDRICH, FREDERICH LAIST and F. F. FRICK, W. L. AUSTIN, and STUART CROASDALE, presented at the Salt Lake meeting, August, 1914, and printed in Bulletins No. 91 and 92, July, and August, 1914. R. C. CANBY, Wallingford, Conn. (communication to the Secretary*). -Apropos of the experimental reduction of copper from cuprous chloride by fusion with ground limestone and coke, as described by Messrs. Laist and Frick, and also proposed for use at Chuquicamata., it might be of interest to refer briefly to the experience at Argentine, Kan., in the smelting of the suboxide of copper (as produced in the Hunt and Douglas process) containing appreciable quantities of chlorides. In the Engineering and Mining Journal of June 10, 1911, I. gave some account of what had appeared to be crucial difficulties with the Hunt and Douglas process, and how the filter-press difficulty had been so rapidly overcome after my discovery of the effect of the sodium salts in the leaching solutions. I also described the effect of the cupola furnace gases upon the lime rock with which I had replaced the coke in the absorption tower, which apparently showed the presence of considerable-chlorine, clue to the imperfect conversion of the subchloride to suboxide, as well as that clue to the difficulties of washing thoroughly the suboxide with the means provided, and also to the presence of chlorides in the cement copper which was smelted With the suboxide. The fumes from the cupola, when issuing direct into the atmosphere, were very dense and white, except when a hot furnace top caused a reddish tinge due to dust. These, fumes had a peculiarly suffocating effect, so that when they were blown over into the town the population suffered the greatest actual distress, not the mere annoyance which would have been clue to a disagreeable odor. The absorption tower had been built at the instance of the city authorities to abate this nuisance, and not with the idea of making any additional metal savings. A serious feature in connection with the Argentine experience with the Hunt and Douglas process was, that it had been implicitly assumed that there could be no metal loss in the Hunt and Douglas process itself, and that all attempts to locate the ruinous copper losses which were accumulating in the metallurgical accounts were devoted to the roasting department. It is possibly unfortunate for metallurgical advance along these particular lines that just about the time of this discovery of this previously unsuspected volatilization loss, in the smelting of the suboxide, the Kansas City company made a contract with the Western Union Telegraph Co. for its supply of copper sulphate and the Hunt and Douglas

Jan 11, 1914

By H. M. Dess, S. R. Bolin

A modifiedl Czochralski technique has been utilized to grow single crystals of YVO, pure or doped with europium or neodymium, from 1 to 2 in. long and 4 to 1/2 in. in dianz. An oxyhydrog-en gas-fired furftace zuas used in this ulork, and melts were contained in iridium crucibles. Successful application of the Czochralski ~vzethod was found to depend upon atmosphere control to prevent crusting and to limit melt decomposition, the establishment of symmetrical thermal gradients in the melt to obtain stable growth, and the selection of high-quality single-crystal seeds to prevent propagation of misorientations during growth and subsequent catastrophic cracking. The suitability of YVO4 as a host for laser-active trivalent rare earth ions has long been recognized. However, the problems associated with the growth of sufficiently large, good-quality single crystals have, until quite recently, seriously hindered satisfactory evaluation of the laser potentialities of this material. Both flux growth and Czochralski growth techniques were investigated at an early stage of interest in YVO,. The former method proved incapable of yielding crystals large enough for practical use,ly2 and the latter was beset with difficulties which took some considerable time to understand and overcome. Recently, however, the Czochralski growth process for YVO, has been improved along separate but similar lines of development by groups working independently in the Crystal Products Department of Union Carbide's Electronics Division and Bell Telephone Laboratories3 so that now good-quality single crystals of satisfactory size can be produced on a routine basis. Stimulated emission from a neodymium-doped YVO4 crystal grown by the Crystal Products Department of Union Carbide was obtained by O'connor4 of MIT, Lincoln Labs. An oxyhydrogen gas-fired furnace was used in this work, Fig. 1, and melts were contained in iridium crucibles. The starting material was 99.9 to 99.99 pct pure YVO4 powder purchased from the Chemical and Metallurgical Division of the Sylvania Electric Products Co. Typical impurity levels, determined by spectrographic analyses, were as follows: Si, 50 to 500 ppm Al, Fe, Mg, 5 to 50 ppm Ni, Pb, Mo, Mn, Ce, Cs, 1 to 10 ppm Initially, YV04 powders predoped with neodymium or europium were obtained from Sylvania. Later, however, because of a desire to grow a series of crystals containing relatively broad concentration ranges of these dopants, it proved more convenient to start with pure YV04 and mechanically admix Nd2O3 or Eu@~ powders plus equimolar amounts of V2O5. The empty crucibles were preheated to 1900" to 1950oC, a temperature range where melting occurred readily. The powdered YVO4 feedstock was then added incrementally. However, a marked tendency toward

Jan 1, 1968

By H. Q. Golder

INTRODUCTION The stabilization of slopes is not a design problem. A slope is designed before it is made. For a slope to be stabilized it must already exist. The basic problem has existed for a long time. It started with cuts in soil and rock made in the 18th century during the construction of the canals which were developed at that time, and continued into the 19th century with the development of the railways, and in the 20th century with motor roads and lately open pit mining. It is not difficult to stabilize a slope, but certain questions must be asked and answered. These are: i) How much stability is required? ii) For how long is it required? iii) How important is the cost? These three questions indicate the basic problem of Civil Engineering, which is that the solution to any problem is a compromise between safety, cost and time. Stabilization of slopes is no exception. If the slope exists why is stabilization a problem? There are many possible reasons, for instance, a neighbouring and similar slope may have failed, or it may be necessary to change the conditions of the slope, steepen it, increase its height, put weight at the top, or construct a building at the foot in which case added security is required, or guarantee its stability for a longer time. MECHANISM OF FAILURE In order to pick the correct method of stabilization the mechanism of failure must be understood and the immediate cause of failure known. Often to remove the cause is the best remedy. The mechanism of failure has been studied over a period of many years in landslide problems. Pit slope failures are very similar to some types of landslides. (1) (2) (3) (4) In one sense there are many causes of landslides. Terzaghi lists 19. This means that there cannot be a standard solution to a stabilization problem. In another sense, it can be said that there is only one cause, which is gravity. This is a constant, never failing force which cannot be

Jan 1, 1971

IT will be recalled that when educational instruction for the mineral industry began at Freiberg, at the beginning of the eighteenth century, the original aim was to organize and systematize the procedures previously followed by young men in gaining familiarity with the technology then in use. There must have been many other ideas current, even then, as to just what a young man needed to learn in order to become capable of assuming responsibility for the supervision and direction of such technical work. The problem in Europe was decidedly different from that in nineteenth-century America, because some of the European mines were actually owned and operated by the governing authority and the others were supervised, regulated, and taxed by it. The American problem was the efficient performance of technical operations; the European one was regulatory supervision. It was natural, therefore, that in the development of educational processes in Europe stress was laid on those factors which conserved and protected the interests of the state. The study of mineralogy and geology, leading to correct judgments as to the workability and value of mineral deposits; assaying, which gave the means of quantitative measurements, as did surveying; chemistry, which furnished a better basis of understanding for assaying, mineralogy, and geology; and physics and mathematics, which are the bases for the understanding and efficient use of mechanical appliances, became the core of systematic instruction for the mineral industry. It was early recognized that men could learn more than was already known about all of these subjects and education took on that dichotomy which still characterizes it; the teaching of established knowledge to the unlearned, and that of extending of the bounds of knowledge, now loosely termed research, which after two and a half centuries of work still shows

Jan 1, 1941

By S Bankoff

INCE1 proposed that electrostatic attraction between oppositely charged particles was responsible for slime-coating. Del Giudice2 postulated the metathetic formation of a cementing compound. Wark3 suggested that prevention of slime-coating was related to peptization of the slime. [ ] In the experiments of Table I the technique employed was essentially that of del Giudice, with the difference that the particle was examined under a film of water rather than dry.4 In general, the polished particle was agitated for 2 min. in a pulp consisting of 12.5 grams of the slime (-200 mesh) and 50 c.c. of distilled water, washed in three baths of distilled water, and examined at 220 diameters with the Leitz Ultropak. Observations of Brownian movement were made at 850 diameters with dark-field illumination. Several of these experiments do not jibe with the metathesis theory. According to published solubilities,5,6 the lead salts of the anions in experiments c through g are more insoluble than lead carbonate, there- [ ] fore should prevent the formation of lead carbonate on the galena surface. In experiment i the calcium oxalate, which presumably was on the calcite surfaces, should have permitted the formation of a lead carbonate cement by virtue of its greater solubility. Experiments j through m show that the addition of lime accelerates the deposition of quartz onto a galena surface. The writer is unable to postulate a satisfactory cementing compound, according to the metathesis theory, to explain this effect. These experiments led to the conclusion that the metathetic formation of a cement-

Jan 1, 1941

By P. Somasundaran, D. R. Nagaraj

Based on our finding that commercial copper chelating solvent extractants such as LIX65NR and LIX63R are excellent collectors for copper minerals, a detailed study was made using several water-soluble chelating agents belonging to the class of aromatic hydroxyoximes and having a gradual structural variation. A basic study of the system salicylaldoximetenorite was also carried out. Microflotation tests as a function of concentration of oxime, pH, addition of copper, etc., using oxidic copper minerals such as chrysocolla and tenorite, and batch laboratory flotation tests using synthetic mixtures of quartz and oxidic copper minerals were carried out. The results have demonstrated that the hydroxyoximes studied have comparable collector property, and in all cases the oxime was found to be partitioned between the mineral surface and the copper in the bulk aqueous phase in the form of a bulk copper chelate. The occurrence of the latter could be accounted for by formation in the bulk phase of a chelate between oxime and copper released from the mineral and/or by the detachment of the surface chelate. The role of surface and bulk chelates in flotation is discussed based on the results of partitioning of chelating agent into bulk and surface chelates in the salicylaldoxime-tenorite system. The effect of structural aspects such as isomerism and substitution in the molecule on the collector property of the oximes is also discussed. Substitution on oximic carbon by alkyl groups is found to promote collector activity. Only the anti-isomer has the ability to collect.

Jan 1, 1982

By A. T. Robinson, J. E. Dorn

The electrical resistivities of aluminum alloys containing CU, Ge, Zn, Ag, Cd, and Mg were found to increase linearly with the atomic percentage of the solute atoms. Application of Linde's rule to these data suggests that each aluminum atom contributes 2.5 electrons to the metallic bond. ALTHOUGH aluminum invariably exhibits a Jt\. valence of three in ionic solids, it does not follow necessarily that its valence in the metallic state is also three. As a matter of record, many properties suggest that the number of bonding electrons in metallic aluminum is less than three. For example, as shown in Fig. 1, the atomic radii1 of the metallic elements in the solid state decrease with increasing atomic number at the beginning of any one period. The atomic radius of aluminum, however, is greater than that which would result from a regular decrease in atomic radius with increasing atomic number, suggesting that the number of bonding electrons in aluminum is somewhat less than three. Correlated with the anomalously large atomic radius of aluminum is its abnormally low melting temperature. As the atomic numbers increase in any one period, the melting temperatures of the metallic elements increase.' As shown in Fig. 2, however, the melting temperature of aluminum (13) is only slightly greater than that of magnesium (12). Again the number of bonding electrons in metallic aluminum appears to be nearer two than the expected value of three. In addition Ageev and Ageeva3 alculated the electron density distribution in the aluminum lattice. A comparison of such electron density curves for various assumed valence states of aluminum with experimentally determined curves suggests that the actual number of bonding electrons in metallic aluminum is between two and three. Hume-Rothery and Raynor', " have suggested that the above-mentioned abnormalities are associated with the overlapping of the Brillouin zones of metallic aluminum when it is in the usual face-centered cubic structure. The importance of the number of bonding electrons in metals has been extended recently into the field of mechanical properties. While formerly it was thought that the plastic properties of alpha solid solutions were primarily dependent upon the lattice strain induced in the solvent by the solute, it is now known that the difference in the number of bonding electrons of the solute and solvent also has its influence on the plastic properties."1' In order to achieve a satisfactory correlation of the effect of alloying elements on the plastic properties of aluminum alloys,"'T however, it was necessary to assume that the number of bonding electrons contributed by aluminum was about two rather than the expected value of three. It appeared to be desirable, therefore, to seek other criteria for evaluating the number of bonding electrons contributed by aluminum to its alpha solid solutions, especially in view of the practical as well as the theoretical importance of the effect of valency on the plastic properties. Norbury' was perhaps the first to illustrate that the increase in resistance of alpha solid solutions is associated with the differences in valence of the solute and solvent metals. In a series of illuminating investigations Linden-'' has shown that the electrical

Jan 1, 1952

By A. A. Smith

THE application of indium to bearings was first advocated by C. F. Smart1 in 1938, for the purpose of inhibiting corrosion of certain bearing alloys. He found that a thin layer of indium plated on the bearing surface and subsequently diffused at elevated temperatures markedly decreased the rate of corrosion in lubricating oils containing organic acids. Most of his work was done on cadmium-base alloys, although he showed that the treatment was also effective for copper-lead and other alloys. Since their introduction, indium-treated bearings have found considerable use, particularly in connection with airplane motors.2 Undoubtedly the effectiveness of the indium plate in resisting corrosion depends upon its relative concentration on the bearing surface after the diffusion treatment and after prolonged use at operating temperatures. Some diffusion experiments were made on a number of base metals that had been indium plated, to determine the depth of penetration after heating for reasonably long periods of time. As only the practical aspects were desired, no attempt was made to determine actual diffusion constants. METHOD Two different series of experiments were carried out to study the diffusion of indium into several base metals. Cast cylinders about one-inch diameter were machined to 0.750-in. diameter, so as to remove all surface imperfections, and final finishing was done with oo sandpaper. The original diameters were very carefully measured with micrometers and then a layer of indium was electrolytically deposited on the cylinders from a sulphate bath.3 In the first series of experiments, about 0.002 in. of indium was deposited and diffusion was carried out at 150°C. for a period of 500 hr. in a thermostatically con- trolled electric oven. After the diffusion period, successive layers were machined from the specimens and analyzed spectro- graphically and chemically-the spectro- graphic examination serving as a guide to determine which layers should be chemically analyzed. Apparently there was some surface oxidation of the indium plate due to the long heat-treatment, which may have had some effect on the diffusion. Also, the cadmium alloy showed some incipient melting, which probably was caused by the formation of a low-melting eutectic. To eliminate these factors, another series of experiments was carried out by heating in an electrically heated, automatically controlled, oil bath at lower temperature. The preparation of the specimens was the same as before except that a layer of indium 0.0001 in. thick, an amount commonly used commercially on bearings, was deposited on each of the cylinders. Diffusion was carried out at l20°C. for a period of 200 hours.

Jan 1, 1944

E. T. DUMBLE, Houston, Tex.-This paper is a continuation of one that was published by Mr. Garfias, I believe, in the Journal of Geology, 1912, in which he gave the results of his investigations in Mexico, showing that the basalt extrusions frequently did not come up as cones. but reached the surface as a small neck and then mushroomed out into a sill, penetrating the beds both in limestones and in shales. He has continued his investigations to show that as these basalt protrusions came up they forced the strata into a funnel shape at the top instead of throwing them out altogether. While this may be true concerning these particular beds, there are other places at which the basalt does appear clearly as cones and dories, and there the funnel structure does not exist. We know that the sills are there, because we find them in the wells. In one well that I know of. we found a 2-ft. sill of basalt at about 1600 ft. and oil below it at about 2100 ft.; others have gone through similar beds. We also know that there. are cones, because north of the Ranuco River one well struck basalt at about 800 ft. and continued in it for several hundred feet-did not pass through it at all. This paper of Mr. Garfias will give us considerable help in that oil field. W. E. WRATHER, Wichita Falls, Tex.-I would like to ask for information as to the temperatures of Mexican oils. I have heard a number of conflicting reports about the high temperatures of the water and oil, and the relationship between them.

Jan 1, 1918

By S. S. Shen, M. J. Pool, P. J. Spencer, J. R. Guadagno

VERY few thermodynamic data are available for rare-earth alloys, partly because of the difficulties of obtaining the metals in sufficiently pure form and also because of their comparative scarcity up to the present time. The rare earths form a very interesting series in the periodic table in view of the progressive filling of their 4f subvalence electron shell and would be expected to provide useful information with regard to alloying characteristics of transition elements. It has been found in recent calorimetric investigations that the heats of solution of a number of the rare-earth metals in liquid tin are highly exothermic.1-4 Exceptionally strong bonding between rare-earth and tin atoms is clearly indicated in the liquid solutions. Continued thermodynamic studies of the behavior of rare earths in solution could thus contribute a great deal to present theoretical knowledge of alloying behavior and would yield an insight into bonding of a strength hitherto unencountered in liquid alloys. The determination of the heats of solution of the pure components in liquid tin is an essential preliminary to calorimetric work of this nature. Heats of solution of praseodymium, neodymium, and samarium in liquid tin at 750" ' and the heats of mixing of Pr-Nd solid solutions' have already been determined in this laboratory. The present investigations with lanthanum continue the study of rare-earth elements. Details of the construction and operation of the liquid metal solution calorimeter used in this work have been published previously by Pool and Peluso and no further description will be given here. The lanthanum used in heat of solution determinations was supplied by Lunex who quoted the purity as 99.9 pct. Their detailed analysis of the material is given in Table I. Samples of 0.0003 to 0.0005 g-atom were used for each run and great care was taken to remove all surface oxide prior to weighing. The samples were stored at all other times in a beaker of oil to prevent their otherwise rapid oxidation. The compounds LaSn (Cudu, L1P type structure) and La&, (structure not classified) were prepared from the appropriate quantities of the two pure components by arc melting under a purified argon atmosphere and once again great precautions were taken to avoid any subsequent oxidation of the specimens. Although no structural examination of the compounds was made, the consistency of thermodynarnic measurements carried out on twenty or so individual samples of each indicates that the compounds were in fact homogeneous, single phase alloys. Samples of the compounds consisting of 0.0003 to 0.002 moles were used in the calorimetric measurements. A solvent bath consisting of approximately 80 g of 99.9 pct pure Sn was used for each series of runs and its heat capacity was determined at regular intervals throughout the experiments using pure tin or tungsten calibration samples. Measurements were made of the heat of solution of lanthanum in liquid tin at 725", 750C, and 775°K and at compositions up to 2.21, 4.76, and 5.25 at. pct La at the three temperatures respectively. In every case, the heat of solution of lanthanum remained constant at its limiting value, within experimental limits, up to the highest lanthanum concentration investigated. Since no change in was observed, it was concluded that the liquid/liquid + LaSn, phase boundary had not been

Jan 1, 1969

By Felix B. Shay

The Agua Fria mine is in eastern Honduras at Lat. 140" 06' N., Long. 86" 36' W. Danli, the seat of the local municipal government, is the nearest town. The property is approximately 44 miles east of Tegucigalpa, the terminus of a truck road from the Pacific coast. The mine lies at an altitude of 3300 ft. with surrounding elevations as high as 6000 feet. For 20 years the oxidized croppings of the Agua Fria vein had been worked intermittently when in 1927 an attempt was made to open the property. A shaft was sunk 300 ft. and considerable ore was blocked out, but before a mill could be installed financial difficulties arose and the mine reverted to the original owners. Erle Y. Halliburton, of Los Angeles, purchased the property in 1934. At that time a careful consideration of all factors involved showed that air transport was the only practical method of moving the equipment and machinery necessary to commence production. The other alternative was by muleback, which required sectionalizing all equipment to a maximum load of 200 lb., and during the rainy season this type of freighting was subject to serious delays. It was decided to purchase a trimotor Ford powered by three Pratt and Whitney Wasp B motors developing 400 hp. each. There were several reasons for the choice: (1) this type of plane was available at a reasonable price, owing to its replacement by faster models on most of the airlines in the United States; (2) the ship was capable of carrying a pay load of 3000 Ib. over the required distance; (3) since this airplane had been widely used there would be no difficulty in securing competent personnel or in purchasing spare parts. It was necessary to rebuild the plane for cargo servicc. The windows were removed and the fuselage was entirely covered. A hatch was cut in the top of the fuselage to receive heavy crane loads and pieces of freight that were too large or too long to go through the rear door. The seats were removed and the interior of the plane was lined with Duralumin sheets. A heavy-duty landing gear was installed and the floor was reinforced. The nearest site for an airport was two miles north of the mine. The necessary grading was done by a small track-type tractor with a wheeled grader, which was brought in overland. Six weeks was required for bring-

Jan 1, 1940

By Felix B. Shay

The Agua Fria mine is in eastern Honduras at Lat. 140" 06' N., Long. 86" 36' W. Danli, the seat of the local municipal government, is the nearest town. The property is approximately 44 miles east of Tegucigalpa, the terminus of a truck road from the Pacific coast. The mine lies at an altitude of 3300 ft. with surrounding elevations as high as 6000 feet. For 20 years the oxidized croppings of the Agua Fria vein had been worked intermittently when in 1927 an attempt was made to open the property. A shaft was sunk 300 ft. and considerable ore was blocked out, but before a mill could be installed financial difficulties arose and the mine reverted to the original owners. Erle Y. Halliburton, of Los Angeles, purchased the property in 1934. At that time a careful consideration of all factors involved showed that air transport was the only practical method of moving the equipment and machinery necessary to commence production. The other alternative was by muleback, which required sectionalizing all equipment to a maximum load of 200 lb., and during the rainy season this type of freighting was subject to serious delays. It was decided to purchase a trimotor Ford powered by three Pratt and Whitney Wasp B motors developing 400 hp. each. There were several reasons for the choice: (1) this type of plane was available at a reasonable price, owing to its replacement by faster models on most of the airlines in the United States; (2) the ship was capable of carrying a pay load of 3000 Ib. over the required distance; (3) since this airplane had been widely used there would be no difficulty in securing competent personnel or in purchasing spare parts. It was necessary to rebuild the plane for cargo servicc. The windows were removed and the fuselage was entirely covered. A hatch was cut in the top of the fuselage to receive heavy crane loads and pieces of freight that were too large or too long to go through the rear door. The seats were removed and the interior of the plane was lined with Duralumin sheets. A heavy-duty landing gear was installed and the floor was reinforced. The nearest site for an airport was two miles north of the mine. The necessary grading was done by a small track-type tractor with a wheeled grader, which was brought in overland. Six weeks was required for bring-

Jan 1, 1940

By G. F. Tagg

Earth-resistivity measurements are often of service in obtaining information regarding geological formations, particularly when applied to structural problems. In such problems the masses of the various bodies are large, and have a corresponding effect on the average resistivity of the soil. Much work has been done using such measurements, but in general the method of interpretation employed is empirical. Since certain simple cases can be investigated mathematically, it appears to be quite sound to endeavor to apply the mathematical solutions to the practical results, in order to deduce from the latter such unknown quantities as depth. This paper deals with such a method of interpretation for the simple case of a single horizontal stratum. In the method described by Wennerl for measuring earth resistivity, four stake electrodes are driven into the earth in a straight line as shown in Fig. 1. A current I amperes is passed between the two outer stakes and the potential difference V volts between the two inner stakes is measured. Then if a is the electrode separation, the specific resistance of the soil, which is assumed to be homogeneous, is given by the formula P = 2?v/1 [1] v or if v/1 is called a resistance R ohms, p = 2?aR [2] If a is in inches, p will be in ohms per inch cube, or ohm-inches, and if a is in centimeters, p will be in ohms per centimeter cube or ohm-centimeters. As stated above, this formula is true only if the earth is homogeneous, and when this is not the case an application of one of these formulas

Jan 1, 1934

By New kensington P. A, W. L. Fink, H. R. Freche

The investigation of aluminum alloy systems prior to 1923 was severely handicapped by the low purity of the best aluminum available. However, by that time, the electrolytic purification of aluminum had been developed by the Aluminum Company of America,(1)† and in May, 1923, there was initiated, under the direction of E. H. Dix, Jr.,(2) a program for the investigation of the aluminum-alloy systems using the purest electrolytically refined aluminum. Up to the present time 15 papers (3) have been published, most of which are on the binary aluminum systems. Work is now in progress on the ternary systems, and it seems probable that most of the future work will be on ternary systems. Therefore this survey of the binary aluminum systems investigatcd up to the present time (the sixteenth paper of the series) concludes the first phase of this program. Certain qualitative relations between corresponding portions of the various binary diagrams as well as between different parts of the same diagram were noted some time ago by R. S. Archer.(4) In the present paper these relations and others are considered quantitatively by the application of well-known thermodynamic equations or by newly discovered empirical relations. No attempt will be made here to present the history of the development of the thermodynamic equations defining equilibrium or their application to metallic systems, although a list of references is given at the end of this paper for those who are interested in this phase of the subject. Two thermodynamic equations, which will be employed extensively in this paper, are: loge x1 = - L/RT + C

Jan 1, 1934

By Frederick N. Rhines

Because of the nature of the environments in which metals are handled, it is natural that gases should be suspected of intruding into metallurgical operations, there to produce effects both beneficial and detrimental. The problem of tracing and controlling such effects is often made difficult by the complexity of the conditions surrounding their occurrellce, even though the fundamental mechanisms invalved may be simple and of familiar type. Many gas-metal reactions are known to be implemented by Processes of diffusion. These form a homogeneous group of phenomena which become more readily understandable when viewed together, in that the knowledge gained from one serves to interpiet the next. It is the purpose of the present Paper to present, by means of examples drawn from practice, a brief survey of the ways in which gas-metal diffusion serves and obstructs the Purposes of the metal-fabricating industries. The selection of the cases described was made by consulting more than thirty-six practicing experts whose combined experience provided an extensive coverage of the field and who were in a position to supply examples of occurrences of present day interest. The response was generous and it is regrettable that space permits the description of only a limited number of typical examples with ' but brief mention of parallel cases. The Nature of Gas-metal Diffusion The term ugas-metal diffusion," although commonly used, is ambiguous in so far as it implies that a definite group of " substances may be identified as gases and may be expected to behave in a manner distinct from other substances in association with metals. "Gases" such as oxygen and hydrogen when diffusing through a liquid or solid metal are properly components of the liquid or solid solution; they behave as alloying elements and are not to be distinguished in their diffusion characteristics from other elements, except that each has an individual rate of diffusion. On the other hand, a number of metals in certain.temperature ranges are volatile to the extent that they may appear in the form of vapor in metallurgical operations. For the sake of greater definiteness, therefore, it will be convenient to regard as "gas-metal diffusion" any process in which the result depends upon one or more of the diffusing elements appearing, at some stage, in the gaseous state, or as a compound gas. NO element, gaseous or otherwise, can diffuse through a liquid or solid metal unless it is at least slightly soluble in that metal. The elements of low atomic number

Jan 1, 1944

By Frederick N. Rhines

Because of the nature of the environments in which metals are handled, it is natural that gases should be suspected of intruding into metallurgical operations, there to produce effects both beneficial and detrimental. The problem of tracing and controlling such effects is often made difficult by the complexity of the conditions surrounding their occurrellce, even though the fundamental mechanisms invalved may be simple and of familiar type. Many gas-metal reactions are known to be implemented by Processes of diffusion. These form a homogeneous group of phenomena which become more readily understandable when viewed together, in that the knowledge gained from one serves to interpiet the next. It is the purpose of the present Paper to present, by means of examples drawn from practice, a brief survey of the ways in which gas-metal diffusion serves and obstructs the Purposes of the metal-fabricating industries. The selection of the cases described was made by consulting more than thirty-six practicing experts whose combined experience provided an extensive coverage of the field and who were in a position to supply examples of occurrences of present day interest. The response was generous and it is regrettable that space permits the description of only a limited number of typical examples with ' but brief mention of parallel cases. The Nature of Gas-metal Diffusion The term ugas-metal diffusion," although commonly used, is ambiguous in so far as it implies that a definite group of " substances may be identified as gases and may be expected to behave in a manner distinct from other substances in association with metals. "Gases" such as oxygen and hydrogen when diffusing through a liquid or solid metal are properly components of the liquid or solid solution; they behave as alloying elements and are not to be distinguished in their diffusion characteristics from other elements, except that each has an individual rate of diffusion. On the other hand, a number of metals in certain.temperature ranges are volatile to the extent that they may appear in the form of vapor in metallurgical operations. For the sake of greater definiteness, therefore, it will be convenient to regard as "gas-metal diffusion" any process in which the result depends upon one or more of the diffusing elements appearing, at some stage, in the gaseous state, or as a compound gas. NO element, gaseous or otherwise, can diffuse through a liquid or solid metal unless it is at least slightly soluble in that metal. The elements of low atomic number

Jan 1, 1944

By James Norman

BARITE (BaSO4) is the most important industrial barium mineral from the standpoint of quantity consumed. In 1938 the amount was 365,000 tons. Its uses are numerous, some of the more important being in the production of pigments, as an inert filler in a wide variety of products, as a weighting material in oil-well drilling muds, in the manufacture of some kinds of glass, and in the production of barium chemicals. The barite studied in this investigation occurs as the massive variety in a shale replacement formation near Magnet Cove, Ark. It is intimately mixed with quartz and small amounts of iron oxide and residual shale. Complete liberation of barite and quartz is not obtained when the rock is ground to loo per cent through 325 mesh. The crude rock with which all test work was done assayed 85.1 per cent BaSO4, 11.11 per cent SiO2, and 2.85 per cent R2O3. Its specific gravity was 4.03. It was found in the course of the investigation that the barite contained a small amount of uniformly distributed carbonaceous material, so intimately dispersed that it could not be seen with the microscope, but gave a definite gray cast to the barite concentrates. The color of the barite in polished sections of the crude rock ranged from gray to almost black, while finely ground powder was a reddish gray. The reddish hue was due to the iron oxide present. In 1939, under the supervision of Oliver C. Ralston,* the Bureau of Mines, in cooperation with the Milwhite Company, of Houston, Texas, undertook to study the flotation of barite from Magnet Cove, Ark. Flotation of several southern barite ores had already been investigated by the Bureau of Mines.' The Magnet Cove barite was unique, however, in that it had to be ground to such an extremely small particle size for liberation. The flotation of nonmetallic minerals in the presence of a large amount of slime is usually very difficult and when done is an innovation calling for conditions different from those under which granular material is separated. LABORATORY FLOTATION WORK Preliminary investigation showed that the flotation reagents recommended by O'Meara and Coe1 for separating barite and siliceous material were suitable, but much larger quantities of reagents were required to separate such finely divided material. Moreover, it was found that careful control of the frothing was necessary. When oleic acid and sodium silicate were used a voluminous froth was observed at the beginning of a test, and toward the end there was not enough froth to effect complete recovery of barite. The addition of pine oil as a frother gave proper frothing for the duration of the test, and the substitution of coconut fatty acid (crude lauric acid) for oleic acid produced a more heavily burdened froth. Two different paper-mill fatty-acid products were tested

Jan 1, 1941

By T. L. Joseph

S. T. Killian (Johnstown, Pa.)—This is one of the finest papers I have read. Tying in stoichiometric calculations with furnace performance and practice is a step which had to be taken sooner or later. The noteworthy difference between Dr. Joseph's type of calculations and regular blast furnace calculations is that the Ib mol system is used as a basis. With the Ib mol system, weights, volumes, and chemical reactions can all be expressed in the same equation. In the paper, wind, ore, flux, and fuel are all expressed as lb or lb mols. Probably Dr. Joseph does not realize it, but the vague word coke appears only twice in the entire paper. Lb of C and Ib mols of C are followed through reactions but the word coke appears only as 1560 lb coke per ton of pig and 1700 lb of coke per ton of iron. Obviously in order to understand furnace reactions, the coke should be expressed as lb or lb mols of C. Furnaces can also be compared more easily. In some respects the paper is too thorough and too complete. The effects of the metalloids reduced into the iron upon the top gases represents a difference of less than 3 pct of the CO formed in the bosh. Due to the completeness of the calculations in relation to the CO/CO2 ratio, this was included and was necessary. However, the exclusion might have enabled more furnace men to follow the lb mol system of calculations through the blast furnace to a better degree. By considering only irons of similar analysis, this part of the calculations might have been omitted. However, if this had been done, total rewriting of the paper later would have been necessary in order to make the work complete as it is now. It also would not have been nearly as authoritative. In the paper, there appears the reaction: H2O + CO ? CO2 + H2 [I] Dr. Joseph states that he did not take this reaction into consideration in any calculations pertaining directly to the paper. The piobable reason- for this is that although it contains all the main reacting top gases except N2, it is rather inflexible since it is monomolecular in relation to each of the reacting gases and does not tie in with the gasification of C. Actually the reactions: H2O + C ? CO + H2 [2] 2H2O + C ? CO2 + H2 [31 and the solution loss reaction: CO2 + c ? 2c0 [41 tend to assume an equilibrium through the reaction: H2O + CO ? CO2 + H2 [I] which should be considered a balancing or equilibrium reaction. Reactions 2, 3 and 4 permit furnace conditions to balance with the CO/CO2 ratio and H2 formation. They tie in with the solution loss. Reaction 1 unites them chemically. Probably the best calculation to make at this time would be to try to find the relative importance of the CO2 from the flux and the H2 in the dilution on an actual furnace gas analysis. For this purpose the Dob-scha-Carnegie-Illinois paper—"Effect of Sized and Sintered Mesabi Iron Ores On Blast Furnace Performance" is chosen. This paper was presented before the blast furnace section of the AIME in 1948. This represents the best large scale furnace operation available to me. Unfortunately the changes were brought about by beneficiation of the burden and not by changes on one burden. In choosing the basis for the calculation in relation to the furnace, 100 mols of dry top sgas is chosen. This leaves something to be desired inasmuch as the nitrogen basis is changing but I believe it will be better understood than any other type and it is the easiest to use.

Jan 1, 1952