Search Documents

By C. K. Leith

OTHERS here are far better qualified than I to discuss some of the specific proposals for government regulation of the oil industry. I shall make no attempt to carry oil to Oklahoma. The question of public control, however, is inherent in other branches of the mineral industry in varying degrees, and my comments will be directed mainly toward some of the trends affecting the mineral industry as a whole, as a background for your more specific consideration of oil legislation. A proud American tradition has been the insistence on freedom of competition, on equality of economic opportunity, on a policy of laissez faire. Nowhere has this principle been given wider application than in the mineral industry. The mineral field has been open to all comers, and the job of mineral exploitation has naturally attracted daring and independent spirits. The laws governing conditions of discovery and development, as well as the anti- trust laws, have been devised to foster the spirit of private initiative. The result has been the building of a mineral industry on a scale never before approximated anywhere in the world. The impetus thus gained, the methods, the technique, the financial resources, have been projected be- yond our boundaries and have made the American mineral industry the purveyor to the world for many essential commodities and first in the exploitation of the world's minerals. Our habits of individual self-reliance and success are deeply ingrained, and there is hardly an individual in the entire mineral field who does not instinctively recoil fro111 the extension of collective control, whether public or private.

Jan 1, 1932

Jan 1, 1971

By C. C. Hawes

SILICA is the main impurity in iron ore. It is intimately associated with the iron oxide, sometimes free but more often in the combined state, as a mineral silicate. Its separation and purification sometimes present difficult problems to the analyst. In the absence of any definite knowledge to the contrary, orthosilicic acid. H4SiO4, is supposed to be the only silicic acid made, all other forms, such as metasilicic acid, H2SiO3, representing different degrees of its dehydration. These acids are exceedingly weak but form the most stable compounds found in nature. They are known as the silicate minerals and are formed by the combination of the different metallic oxides

Jan 1, 1936

By AIME AIME

THE graduating class whom I am particularly addressing are going into the world at least a month earlier than normal, because of the war. You have been free to choose your work. You have chosen to be mining engineers. The principal importance of your engineering education to date has been in teaching you how to think and how through books to have ready access to the accumulated experience of previous generations, as well as the current experience of the day. You should by now have acquired something of the engineering point of view, the open skeptical mind. the power to observe, experiment, and draw conclusions, form theories and test these by further experiment, and weigh the inherent probability of conclusions drawn by others. I am asking you today to consider certain facts and the conclusions I am drawing from those facts.

Jan 1, 1942

By J. H. Nead, T. S. Washburn

The grades of commercial steel produced in large quantities can be divided into two general types from the standpoint of ingot structure— killed and rimmed. Killed steel covers a wide variety with carbon contents throughout the range of the steel portion of the iron-carbon diagram, and is the kind usually used in the production of alloy steels. Rimmed steel is normally associated with carbon ranges under 0.30 per cent, and is not yet used to a large extent in alloy practice, except for copper-bearing steels. The fundamental differences in the ingots made from these two types of steel can be seen most easily in Figs. 1 to 7. In the rimmed ingot shown in Figs. 5 to 7 there are two lines of blowholes approximately parallel to the sides and coming together at the top and at the bottom of the ingot. In the killed ingots shown in Figs. 1 to 4 these blowholes arc not present. Also, the rimmed ingot has no well defined pipe, as compared to the deep pipe on the killed ingots, and there are numerous primary blowholes in the lower portion of the rimmed ingot perpendicular to the surface and close to it, while on the killed ingot there are no blowholes of this type in the ingot shown in Fig. 1 and very small ones close to the surface in the lower part of the ingot shown in Figs. 2 to 4. With respect to the presence of pipe and the primary blowholes, the structure may vary considerably in both rimmed and killed ingots, therefore these cannot be considered as fundamental structural characteristics differentiating the two types of steel. The primary blowholes in rimmed ingots may be much less pronounced than those in the ingot shown in Figs. 5 to 7—as, for example, in "ingot iron," which is entirely free from them. An example of a cross section of an ingot-iron ingot is shown on page 16 of "Research and Methods of Analysis of Iron and Steel," published by the American Rolling Mill Co. (1920). A certain amount of pipe may also occur in rimmed ingots, though it is normally porous and not as well defined [or deep as in the killed ingot of Fig. 1. In killed ingots, primary blowholes may occur near the surface, as in Figs. 2 to 4, and

Jan 1, 1937

By G. L. Kulcinski, R. D. Leggett

Irradiated uranium containing 635 ppm of carbon, mostly in the form of UC precipitates, was annealed at temperatures from 650" to 900°C under hydrostatic pressures of 0 to 1000 bars. Postirradiation examination revealed that the carbide particles are not stable in the r phase of irradiated material but are stable in unirradiated material annealed under identical conditions. The degree of carbide dissolution appears to be connected with the fission product concentration and independent of annealing pressure. THIS paper describes the change in appearance of carbide particles in irradiated uranium after the uranium has been postirradiation-annealed. It has been proposed by several investigators&apos;-5 that fission gas-induced swelling in irradiated uranium may be reduced by incorporating a fine dispersion of second-phase particles into the metal. Because of the low solubility of carbon in uranium6 and the apparent stability of UC precipitates at high temperatures,6-8 this system has received some attention. The stability of UC particles to low-temperature irradiation has been demonstrated many times, as well as their stability during postirradiation anneals in the high a or B phases.9 Unirradiated uranium containing UC particles has been annealed high in the r phase, and the solubility of carbon was found to be only -115 ppm at 1050ºC.6 Vacuum annealing of irradiated uranium to the same temperature produces a spongelike sample, due to the formation and growth of fission gas bubbles."14 This highly disrupted lattice has made any determination of the stability of UC at these temperatures impossible. Nevertheless, it has always been tacitly assumed that the UC particles were still present. Recently, postirradiation, high pressure-high temperature tests have been performed on irradiated uranium containing a secondary phase of UC. 14 Examination of these samples after 100-hr, 900°C tests revealed that the carbides are not stable, and the results of these tests are presented here. 1) EXPERIMENTAL PROCEDURE The samples, high-pressure equipment, and subsequent analytical techniques are the same as those described elsewhere.14,15 Briefly, cylindrical samples of commercial-purity uranium that had been irradiated at <350°C to 0.37 at. pct B.U. were subjected to 90O°C, 100-hr anneals in NaK at pressures ranging

Jan 1, 1970

By Robert C. Linares

Cubic zinc sulfide has been grown from molten salt solutions substantially below the hexagonal-cubic phase transition of 1020°C. Crystals free of birefringence have been grown from molten lead chloride at temperatures from 500° to 800°C. Factors affecting the optical transmission and the birefringence are discussed. CUBIC zinc sulfide is of interest for electrooptic devices and as an optical coating material. However, it cannot readily be produced as large crystals which are free of birefringence. The birefringence arises from the fact that the cubic ZnS is usually grown as the high-temperature hexagonal phase and is transformed to the lower cubic phase by annealing.&apos; This results in stacking faults, stress, and birefringence. A requirement for the growth of cubic ZnS is that it be grown below the phase transition of 1020°C.2 Crystals of cubic ZnS have been grown below 1020°C by the hydrothermal,3 flux,4 and vapor transport5 techniques. However, these all appear to have limitations in size or quality of material produced. It was felt that a new flux method might have a good chance of overcoming some of the previous problems. Mita6 reported the growth of hexagonal ZnS from molten NaCl and wilke7 reported the growth of iron sulfides from molten lead chloride solution, indicating that molten chlorides make good solvents for sulfides. An investigation of a number of possible molten chlorides as solvents showed that molten PbCl2 has an appreciable solubility for zinc sulfide and that crystals can be grown at temperatures from 500° to 800°C. EXPERIMENTAL Crystal growth was performed in open or sealed Vycor or fused silica tubes, in an argon atmosphere or vacuum. There were no deleterious effects due to using vacuum; however, a sealed essentially isothermal system must be used to prevent vapor transport mechanisms from dominating. This will be discussed later in detail. Noble metal containers were not usable as they were severely attacked by these melts. The materials used were: reagent-grade PbC12, reagent-grade ZnS, optical-coating-grade ZnS, and Irtran 2 (ZnS). Crystal growth was accomplished by both slow cooling techniques and gradient growth techniques. In the slow cooling techniques, 15 g of ZnS and 100 g of PbCl2 were used. The components were placed in the silica tube, heated at 800°C for 2 hr, and then slowly cooled (l° to 10° C per hr) to 500°C. The furnace was constructed so that the tube could be inverted, thus allowing the liquid to drain off the crystals at the end of the run. The gradient runs were made by placing the above mixtures in a silica tube at 550° to 600°c, Fig. 1. A temperature gradient was maintained such that the floating mass of undissolved sulfide was 10° to 50°C warmer than the bottom of the tube. Growth occurred on spontaneously nucleated sites at the cooler bottom. RESULTS When using high cooling rates (5° to 10°C per hr), crystals form in thin sheets perpendicular to the {111} face. Crystals 5 by 5 by 1.2 mm, Fig. 2, have been ob-

Jan 1, 1969

By W. R. Ingalls

IF, in this study of the outlook for the copper industry of the United states, I find myself assuming to be prophetic in some respects I shall express myself with hesitation and with the foresight that after the end of the war with Germany the war with Japan may continue; anyway there is sure to be an uneasy period before copper and the other metals begin to flow smoothly through the natural channels of consumption. It is mainly my purpose to survey conditions and suggest some probabilities, or possibilities, rather than to prophesy. In interpreting them it will be necessary to make certain aasurnptions, among which will be (1) expectation of a rise in the general price level,, which so far has been one-sided; (2) continuance of the k. tariff on copper imports; and (3) lock-up of government-owned copper as a military re- serve. Of these assumptions the first is indicated by the lessons from economic history, and by current symptoms. The second and third depend upon political action by Congress.

Jan 1, 1944

By Gordon MacVean

THE adoption of rock dusting, as a safety measure, has made notable progress in the West Virginia coal mines since May, 1925. At that time there were but two mines in the State that were thoroughly rock dusted, mines No. 2 and No. 12 of the Boone County Coal Corp., at Sharpless. Since then it is probable that 75 per cent of the coal operators in the State have given consideration at one time or another to rock dusting. This growth of interest followed the meetings of the various mining institutes all over the country, during the summer of 1925, at which papers were presented, drawing the attention of the coal mining operators to the merits of this safety measure. Yet outside of the experience with rock dusting at the Old Ben Coal Corp., of Southern Illinois, and the Carbon Fuel Co., of Rains, Utah, there had been no actual occurrence in the coal mines of the United States, which could be taken as positive evidence of the efficacy of rock dusting in the prevention of the propagation of coal dust explosions. The U. S. Bureau of Mines, however, had run innumerable tests under conditions which closely approximated actual coal mining conditions and had clearly shown that rock dusting was effective.

Jan 1, 1926

By EDWARHD HALSE

Discussion of the Paper of Dr. H. M. Chance, presented at the Lake Superior Meeting, September, 1904. EDWARD HALSE, Puerto Berrio, Colombia, So. Amer. (communication to the Secretary*) : The Taviche mining-district is generally known as a Taviches," being named from the two villages called respectively San Pedro Taviche and San Jeronimo Taviche. It is so called by José G. Aguilera, in his paper on the Geographical and Geological Distribution of the Mineral Deposits of Mexico;&apos; and in published reports by the late N. W. Rudston Read ;2 and by Juan de Dios Villarello.3 The region is a large one, measuring about 24 miles long and 7 miles wide. Dr. Chance, in his interesting paper, tells us very little about the nature of the ores, and, with regard to the geology of the district, contents himself with observing that ? the country, as a rule, consists of eruptive rocks; and no evidences of sedimentary strata appear near the mines.? The latter part of the above statement is hardly correct. The formation is mainly eruptive, being hornblende-audesite of Tertiary age, which is limited on the east by the calcareous (Cretaceous) formation, and on the west by the Huronian rocks of Ocotlan. Limestone is seen close to the Santa Càtarina mine, at the northern end of the region. In the surface-working known as La Cueva, a little northeast of San Pedro, limestone forms the eastern wall of the deposit which consists of spots (moscas) of pyrargyrite in white opaque or transparent quartz. Ill one place the ore is associated with stibnite, and the quartz frequently exhibts a

Sep 1, 1905

By C. E. Berner

Since 1933, the Coal Mine Rating Schedule in Pennsylvania has provided credits in the Workmen&apos;s Compensation insurance premium rates for the use of safety hats, goggles and shoes. In that year, the worth of such protective clothing had just been well established and satisfactory articles were being made by a number of manufacturers. Standards for these three items of safety clothing&apos; were written in the Rating Schedule and have been little changed through the years. The credit in the premium rate for a bituminous mine is $0.14 for hats, $o.08 for goggles, $o.08 for shoes. In order to earn such credit, it is necessary that all the employees in the particular mine be equipped with safety hats, goggles or shoes, as the case may be. In fact, it is not unusual for mines to qualify in all three categories, thus earning a rate reduction of $o.30 per $100 of payroll. These credits have been a decided stimulus to the use of safety clothing, and at present insured bituminous mines are credited as follows: Hats........ 63 per cent, or 22,600 employees Goggles..... 28 per cent, or 10,000 employees Shoes....... 44 per cent, or 15,800 employees Of course, many other employees wear these protective articles but they are in mines that are not fully equipped and so are not given the rate credit. The growth in use of this equipment has not been spectacular but it has been steady, as shown in Table I. An interesting thing about this is that it covers virtually all of the small and medium-sized bitumi- nous mine operations in Pennsylvania. A number of large operations are included, but many large mines are self-insured. It is difficult to keep alive interest in safety work in the smaller mines: first, because employment of safety engineers is out of the question and the one or several mine officials employed are often concerned only with production; second, because the life of many small mines is brief, so that safe conditions although established do not last long. Conditions as to safety in mines of this class rest chiefly with inspectors of state mine departments and of casualty insurance companies. Many millions of tons of production come from these mines, so that

Jan 1, 1944

By C. E. Berner

Since 1933, the Coal Mine Rating Schedule in Pennsylvania has provided credits in the Workmen&apos;s Compensation insurance premium rates for the use of safety hats, goggles and shoes. In that year, the worth of such protective clothing had just been well established and satisfactory articles were being made by a number of manufacturers. Standards for these three items of safety clothing&apos; were written in the Rating Schedule and have been little changed through the years. The credit in the premium rate for a bituminous mine is $0.14 for hats, $o.08 for goggles, $o.08 for shoes. In order to earn such credit, it is necessary that all the employees in the particular mine be equipped with safety hats, goggles or shoes, as the case may be. In fact, it is not unusual for mines to qualify in all three categories, thus earning a rate reduction of $o.30 per $100 of payroll. These credits have been a decided stimulus to the use of safety clothing, and at present insured bituminous mines are credited as follows: Hats........ 63 per cent, or 22,600 employees Goggles..... 28 per cent, or 10,000 employees Shoes....... 44 per cent, or 15,800 employees Of course, many other employees wear these protective articles but they are in mines that are not fully equipped and so are not given the rate credit. The growth in use of this equipment has not been spectacular but it has been steady, as shown in Table I. An interesting thing about this is that it covers virtually all of the small and medium-sized bitumi- nous mine operations in Pennsylvania. A number of large operations are included, but many large mines are self-insured. It is difficult to keep alive interest in safety work in the smaller mines: first, because employment of safety engineers is out of the question and the one or several mine officials employed are often concerned only with production; second, because the life of many small mines is brief, so that safe conditions although established do not last long. Conditions as to safety in mines of this class rest chiefly with inspectors of state mine departments and of casualty insurance companies. Many millions of tons of production come from these mines, so that

Jan 1, 1944

By R. H. Lynn, T. C. Craig

During the year 1933, in the Texas Panhandle, 113 oil wells were completed, adding 33,337 bbl. to the daily potential of the field. The field potential on Jan. 1, 1933, as determined by the Texas Railroad Commission, was 149,260 bbl., with a daily allowable production of 41,000 bbl. The potential was raised gradually, until on July 16, 1933, it reached 155,344 bbl. with a daily allowable of 55,000 bbl. This potential and allowable was maintained over a period from July 16, 1933, to Sept. 8, 1933, when the potential was reduced to 136,893, with a daily allowable of 43,727 bbl. Since Sept. 8, 1933, there has been a gradual increase, until on Jan. 1, 1934, the field potential reached 159,740 bbl. with a daily allowable of 42,000 bbl. Of this amount 26,429 bbl. arc "marginal oil" and 2682 bbl. are exempt on account of water. Deepening of Wells During the year 64 wells were deepened, increasing their total oil production 9631 bbl. per day. Of this amount the Gray County granite wash contributed 9256 bbl. from 57 wells. It has been found in many places that the granite wash carries an additional oil pay from 50 to 75 ft. below sea level. The majority of the wells that were .drilled during the early development in Gray County encountered their oil above sea level. When the wells producing from the upper horizon have become unprofit-

Jan 1, 1934

[Secretary&apos;s Note.—The following official tables, prepared by the government of the State of Nuevo Leon, and presented to the Institute at the fifth seseion of its Mexican meeting, held at Monterrey, November 26, 1901, present in compact form a general summary of the mineral and metallurgical industry of the State for the preceding calendar year, together with a statement of the railway-shipments of ores from January 1 to October 31, 1901, which, in the absence of direct official mining and metallurgical statistics (not yet available for that year), clearly indicates an increased activity and productiveness of these industries. In other words, the mines are reported to have yielded in 1900 a total product of 83,960,169 kilos of ore; whereas, the railway is reported to have carried, in 10 months of 1901, a total of 108,318,647 kilos of ore. At this rate, the railway-shipments for 1901 mould amount to nearly 130,000,000 kilos. It is, of course, possible that the railwaystatistics include other freight than ores, or that they include duplications, such as would be involved in the record, first of certain ores transported, and afterwards of the " base bullion " produced therefrom. An accurate comparison is therefore impossible ; yet, after making all reasonable allowances for such items as have been named, it seems safe to infer that the mining and metallurgical industry of this State accomplished in 1901 a substantial progress.]

Jan 1, 1902

By A. E. Brugger

SOME 2,000 years ago Pliny is supposed to have said, "Out of Africa always something new." It may perhaps even now be news to a great many that the Belgian Congo has in recent years been producing approximately a quarter of a ton of diamonds annually. For that is what the 1 1/4 million carats, the recovery from 40-odd operating mines, and about 20 or 25 per cent of the world&apos;s normal consumption, amounts to. In 1915, first exploitation operations produced less than 50,000 carats from two mines. The rapid expansion of operations following the Euro¬pean war meant a most rapid development of a virgin land. The interior is now reached by air in one day from the mouth of the Congo River, where steamers unload mail and passengers from Antwerp. This trip formerly consumed 4 to 6 weeks by a narrow-gage, wood-burning, railroad around the rapids of the lower Congo and Livingston Falls; by river boat to the heads of navigation, Djoko Punda on the Kasai or Luebo on the Lulua; and thence by caravan of native porters over narrow-trails to head¬quarters on the Tshikapa. Hundreds of miles of automobile roads have been constructed over veldt and through forest, bridging streams and ferrying rivers. The railway from Capetown to the Katanga copper district to the East, once two months away by trail is now reached in 2 or 3 days over fair automobile highway. Native "boys" who a few short years ago wore little more than a smile and a string of beads and to whom a wheelbarrow was a complicated piece of machinery, are today driving Fords, tending boilers and engines and operating electrical equipment, or are capable mine workmen, machinists and artisans, and dressed in all manner of cast-off white man&apos;s clothing. Even as late as 1920, due to difficulties of securing and transporting machinery during and just after the war, the crudest hand operations were the rule for the excavation, sizing, and concentration of the diamondiferous gravel. All washing and concentration is now mechanized, using steam or electric power, and where operations are sufficiently large to permit competition with native labor costs, excavation and transportation are also accomplished by machinery.

Jan 1, 1932

By F. B. Sherman, Keros Cartwright

Sanitary land filling has become one of the most widely used methods of disposing of solid refuse. A principal concern of regulatory agencies and the public itself is that landfill operations do not degrade the physical environment, including water resources, and the ground-water reservoir in particular. Knowledge of ground-water and engineering geology can guide landfill operations into suitable terranes or develop measures to compensate for natural limitations at a particular site. Experience and research in Illinois suggest four activities relating to landfill disposal that warrant attention by geologists and engineers: (1) regional delineation of favorable and unfavorable hydrogeologic conditions to facilitate planning and preliminary screening of potential landfill sites; (2) site evaluations, with considerations of geologic materials, topography, water levels, flow systems, and local occurrence and use of water resources; (3) research on aspects of the hydrogeologic environment that control effects of, or are modified by, landfills; and (4) formulation of practices in the siting, construction, and operation of landfills that prevent, mitigate, or isolate deleterious effects. The first two activities are basically in the domain of earth science, requiring the application of fundamental concepts of geology and hydrology and conventional site-exploration methods. The third activity, research, requires contributions from geology as well as other disciplines, including soil physics, sanitary engineering, and chemistry. The fourth calls for policy decisions by regulatory agencies and elected officials, using the contributions of scientists and engineers. Throughout history, man has disposed of unwanted materials by dumping. As urbanization has increased, haphazard dumping practices have given way to disposal under more controlled conditions because of increasing congestion of population and production of waste and greater concern for public health and environmental amenities. Many states and communities have already outlawed open dumping and open burning of refuse. The only practical methods of disposal of large volumes of refuse, therefore, are contained, high-temperature incineration, or burial in a sanitary landfill. In Illinois, regulation of solid waste disposal has been delegated to the Environmental Protection Agency. Each session of the legislature since 1965 has passed increasingly strict laws regulating waste diposal. As a result, the work of evaluating sanitary landfill sites has increased significantly for both the Department of Public Health, now the Environmental Protection Agency, and the Illinois State Geological Survey, which advises the Agency on matters of ground-water geology and pollution. In fact, our ground-water staff spends as much time on studies relating to waste disposal, primarily sanitary landfills, as on ground-water resource studies. Many other geological agencies are experiencing similar demands for increased assistance in solving waste-disposal problems. This paper summarizes some of the salient features of the sanitary landfill concept, describes activities of the Illinois Geological Survey in ground-water and engineering geology relating to landfills, and suggests policies that need consideration. A sanitary landfill is located and operated in such a way that vermin and pests, nuisances, and degradation of air and water are kept at acceptable levels. Some of the physical requirements of a sanitary landfill are all-weather roads for year-round access, fences to retain blowing paper, a daily cover of at least six inches of suitable earth material, and a final cover of at least 2 ft of earth material. Dumping into or adjacent to standing water generally is not allowed. Two common operating techniques are used. In the first, trenches are dug, the refuse is placed in them, and the earth removed from the trenches is used to cover the waste. In the second method, area fill, refuse is placed in low ground and covered with earth from adjacent high areas. The hydrology of the site is a prime consideration in locating sanitary landfills. Putrescible refuse, if saturated above field capacity, produces a leachate that usually has a high concentration of dissolved solids.2 As the leachate also acts as an agent for transporting bacterial pollutants, it constitutes a potential pollution hazard. To reduce the production of leachates, the topography of the landfill area should be such that surface water will not flow into or through the fill. Operations that will result in refuse disposal below or near the highest known water-table elevation may be required to take corrective or preventive measures to protect the ground water. In practice, under humid conditions such as prevail in Illinois, locations where disposal can take place above the water table are relatively few because surficial materials are commonly fine-grained, which permits slow gravity drainage and results in high degrees of saturation (100% moisture content) near the surface. At some sites, although disposal has taken place above the water table, ground-water mounds have developed, resulting in permanent saturation of the refuse. Permeability barriers usually are required to protect the ground-water reservoir from degradation by leachates. The convention in Illinois is to have a minimum of

Jan 1, 1972

By H. H. Podgurski, F. N. Davis

In silver alloys containing less than 0.2 wt pet Cu. the reaction 9 + 1/2 0, = CuO(s) was found to proceed to equilibrium between 700o and 808oC. From measurements of the equilibrium dissociation pressures of the CuO at several temperatures, the differential heat of solution and the activity coeflicients for copper in silver were calculated. These values were found to be in reasonable agreement with those calculated from data appearing in the literature. A metastable "copper oxide" with an atom ratio of oxygen to copper as high as 1.7 was formed by internal oxidation at 300°C of these same dilute Ag-Cu alloys. No anomalous behavior was noted in the temperature dependence of oxygen solubility in silver. The solubility minima between 300" and 800°C reported several years ago can be accounted for, at least in part, by reactions with trace impurities, such as copper. Cold-worked siloer exhibits an enhanced permeability to oxygen. THIS investigation was undertaken because of our interest in interactions between solute and lattice defects in metals. The reason for the choice of the O-Ag system for study is the anomaly in the solubility of oxygen in silver reported by Steacie and Johnson1 in 1926, specifically that isobars between 100 and 800 Torr show solubility minima at 400°C. It was also claimed that the copper impurity in the silver was not responsible for the minima. Recently, Eichenauer and Müller2 proposed that surface adsorption might have been responsible for this solubility anomaly, but no adsorption isotherms are available to check the pressure and temperature dependence observed at the low temperatures. Surface-tension measurements on silver made by Buttner, Funk, and udin3 suggest that a considerable fraction of a monolayer of oxygen exists on silver at 922°C and at an oxygen pressure of 150 Torr. To account for the pressure sensitivity reported by Steacie and Johnson1 at 300°C, the oxygen bound to the surface at 922°C cannot be considered relevant; the existence of a surface layer at 300°C characterized by a lower energy of binding would be required to explain the effect. All of our attempts to detect an interaction of this type with surface sites have failed. In this investigation we have not been able to associate the dissolution of oxygen in silver with a dislocation interaction. Evidently, severely cold-worked silver does not contain a sufficient number of trapping -sites for oxygen. Indeed, our work shows that oxidation of trace impurities in the silver was probably responsible for Steacie and Johnson&apos;s results. In addition, we have been able to establish the nature of the reaction with copper impurity in silver by thermodynamic considerations. EXPERIMENTAL PROCEDURE Measurements of both the internal oxidation rates and the solubility were made volumetric ally in a system equipped with a gas burette, a mercury manometer, a McLeod Gage, and a mass spectrometer. The silver and the silver-alloy samples were protected from contamination by mercury vapor from our pressure gages by suitably placed refrigerated (-78°C) traps. Silica reaction vessels were employed for experiments performed above 500°C. Spectroscopically pure gases were used in this investigation. The highest-purity silver used in the solubility measurements was 99.999 pet. By chemical analysis 2 ppm of Cu were found in this silver. The two Ag-Cu alloys used in this research were made up to 0.14 and 0.15 wt pet Cu starting with 99.999 pet Ag. An unexpected source of error was discovered in the course of the work. At temperatures near 800°C silver distilled from the hot silica reaction tubes into cooler regions of our system. Although the weight loss of silver from the sample was not important in itself, oxygen was being consumed by the silver distilled into the cooler part of the system to form a stable oxide phase from which the oxygen was not recovered. In a separate experiment conducted to determine the necessary correction, losses between 0.2 and 0.3 cu cm (stp) of 0, in 24 hr were measured at 810°C. On the assumption that the flux of silver from the vessel to form Ag2O de-

Jan 1, 1964

By R. C. FLEMING

G OLD MINING is enjoying a real revival in the West, and a considerable portion of the production is coming from small properties. The large mining companies of the world get most of the publicity, but in the last year the small gold property has often proved a more attractive field for the mining engineer looking for something to do. Old mines have been re- opened, prospects have been more closely examined, and many properties that were out of the running with the high commodity and labor costs of two or three years ago, have recently been making money for their operators. An interesting phase of this activity is the operation of so-called one-man mines. The west is dotted with these small properties, without the resources or reserves to warrant large-scale operation, but which return a living and often something over to one or two men who under- stand mining and simple methods of treatment.

Jan 1, 1932

By E. T. Hunter

Surrounded by the 13,000-ft high peaks of the San Juan Mountains in southwestern Colo., the town of Silverton is the site of the extensive development operations initiated 20 months ago by Standard Metals Corp. Appropriately termed the Silverton Project, Standard&apos;s operation has now passed the half-way point in its program to reopen two mines that were once sizeable producers of copper, lead, and zinc ores.

Jan 1, 1961

By R. W. Powers, M. V. Doyle

ThE solution of a diatomic gas such as 0, or N2 in a metal usually follows Sieverts&apos; law; i. e., Here C is the solute concentration at equilibrium and P, the gas pressure. The proportionality constant Ks is also the equilibrium constant for the reaction 1/2 02 (at pressure, P) - 0 (in solution at [21 concentration., C). to use oxygen as an illustrative gas. Sieverts&apos; law is therefore interpreted to indicate that diatomic gases go into metallic solution atomically and that the solute "gas" atoms interact negligibly with each other. Of course, this interpretation is strictly valid only over the temperature interval in which the reaction indicated in [Z] can be investigated. At temperatures several hundreds of degrees below this interval, the possibility of interactions between solute atoms is conceivable. Indeed, from internal-friction measurements some evidence for the existence of groupings of oxygen atoms in tantalum solid solutions was presented a few years ago.1,2 Over a range of solute concentration, the experimental oxygen internal-friction peak in tantalum, measured as a function of temperature at constant frequency of vibration, can be described as the sum of two elemental peaks, each corresponding to a separate relaxation process. At 0.7 cps, the height of the elemental peak found at 137°C is proportional to the oxygen content, whereas the height of the one at 162°C varies as the square of the oxygen concentration. The 137°C peak was presumed to arise from the stress-induced ordering of oxygen atoms among various classes of octahedral sites in the manner proposed by Snoek.3 The 162°C peak was attributed to a somewhat similar stress-induced ordering process, in which each oxygen atom was interacting with a neighboring oxygen atom. Similarly, the experimental peak due to nitrogen in tantalum can also be described as the sum of two peaks. The height of one varies as the nitrogen concentration and the other as the square of this quantity. In fact, some evidence of solute interactions exist for all oxygen and nitrogen solid solutions of Group V transition metals. However, the interaction energy was not obtained previously for any alloy. The determination of this quantity, as a part of a more intensive study of the interaction between oxygen atoms in solid solution in tantalum, is reported in this paper. PRINCIPLE OF THE EXPERIMENT Consider an equilibrium in a solid solution of tantalum between oxygen atoms which are bound together pairwise and those solute oxygen atoms which are not so associated. 20 (Ta) - O2 (Ta) [3]

Jan 1, 1960