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By W. L. Freyberger, H. Alter, K. L. Woodruff, E. L. Michaels

Laboratory and pilot scale tests have been made to determine the utility of heavymedia separation, particularly a cone-type separator, as a means of recovering aluminum and other values from shredded municipal solid waste. The effect of the method of shredding on the behavior of aluminum in a heavy-media system was determined. Two-stage pilot-scale heavy-media separations were made with size fractions of shredded refuse. Recoveries of aluminum, as well as other components of the refuse, were measured and medium losses determined. The experimental results indicate that with certain reservations a heavy-media cone system can be utilized for aluminum separation and recovery from shredded and air-classified municipal solid waste. Observations made using two-stage heavy-media separation in a drum unit are included. Qualitatively, the results from the two types of separators are similar.

Jan 1, 1976

By H. L. Sauder, J. L. Newman, C. Waddell

An instrument capable of measuring subsurface flow rates is described. The instrument is self-contained and may be run on piano wire line. It detects flow by means of an impeller suspended between two torsion wires. The force of the well fluid striking the impeller causes the impeller to rotate, exerting a torsional force to the wires. This force is determined by recording the angle of rotation of the impeller on film using a battery-driven, clock-controlled camera. The impeller is sensitive to flow in either direction and the same instrument can be used to measure injection as well as production rates. Changes in direction of flow, such as might be caused by thief zones, are measurable and are indicated by a reversal of the direction of rotation of the impeller. Adjustment of the sensitivity of the instrument to measure a wide range of flow rates is accomplished by the use of different size torsion wires. An umbrella-type fluid trap, which contacts the casing or wellbore, diverts the flow through the flow tube. The fluid trap remains closed while rurrning in the hole and can be opened at any point in the well. The instrument with the trap closed is 1 3/4 in. OD and may be run through 2 in. tubing. Successful flow profiles have been made on wells with flow rates ranging from 60 BID to 4,000 B/D at surface pressure up to 4,500 psi. The instrument is designed for high-pressure and high-temperature operations. INTRODUCTION The need for an instrument that will measure flow rates in a wellbore is as old as reservoir engineering itself. A number of such devices have been designed within the past few years. Some of these have been described in the literature1,2,3,4,5,6 One of these devices1. a hot-wire anemometer type, made many successful jobs in dry gas producing areas. Difficulty was encountered when this flowmeter was used in wells producing liquids and development work was initiated to overcome this difficulty. The present flowmeter is the result of this work and provides an instrument with a wider range of application in the industry. Consider- able development work has been done on the tool involving many changes in the mechanics of recording the flow readings, however, the basic principle of flow detection has remained the same since its inception. PRINCIPLE OF OPERATION The basic principle of operation of the flowmeter is the utilization of a portion of the kinetic energy of flowing well fluid to impart a rotational force to an impeller suspended between two torsion wires. This impeller, Fig. 1, is a screw-type propeller with the blades having a pitch angle of 40. As the well fluid passes through the instrument it strikes the impeller. The resulting force rotates the impeller and twist\ the torsion wires to a balance point at which the torque imparted to the wires balances the force required for the impeller to deflect the well fluid. The impeller is symmetrical and a change in direction of the flow results in a reversal of the direction in which the impeller is deflected. Thus the direction of the flow as well as its velocity is indicated. A dial is attached to the impeller by means of a hollow tube through which the upper torsion wire extends. The angular position of the impeller is recorded by photographing the dial at frequent intervals. In any given set of torsion wires the modulus of shear and polar moment of inertia remain constant and the deflection varies directly with the applied torque. The deflection imparted to the torsion wires also varies as the square of the fluid velocity. Further, the velocities represented by any two given deflections hear the following relationships: and Where V = velocity of flow stream and O ;= deflection. This is the basic relationship which is used to calculate the relative velocities represented by a given set of deflections where the velocity represented by any one of the deflection readings is a known quantity. For a given torque, the deflection of the torsion wire varies inversely as the fourth power of the wire diameter. Wire sizes ranging from ,005 in. in diameter to .022 in. in diameter can be used. The range of

Jan 1, 1957

By Francis A. Thomson

IN reviewing mineral industry education a year ago, occasion was taken to congratulate the Institute in general and to felicitate the Education Di- vision in particular on "the most gratifying growth which is taking place in Institute consciousness in regard to its responsibility for the recruitment and adequate training of student personnel and for the successful bridging of the difficult gap between graduation and achievement of professional status." Continuation of this growth of interest throughout 1939 is a recognition of the validity of the splendid statement of George Otis Smith that the mining students of today are the ore reserve of the Institute for the future. In this connection one recalls the equally apt expression of another distinguished geologist, George M. Fowler, who, speaking of exploration for ore deposits, says, "The place to look for elephants is where elephants have been found."

Jan 1, 1940

By S. A. Braley

DRAINAGE water from coal mines is probably the most serious water pollution problem today, varying in importance according to location of the mines and geological structure. Drainage may be either acid or alkaline in character. Acid discharge, the most severely detrimental to a stream, is caused by natural oxidation of the sulfuritic material (FeS2) in the strata associated with the coal seam. Since the acid is the result of a natural reaction the acid water differs because it does not cease with abandonment of the mining operations. There is no known economical method of neutralizing acid mine water or any practical method to prevent oxidation of exposed pyrite. Since production of acid from a mine does not stop when mining stops, the total quantity produced depends entirely upon the excavated areas. The increasing volume of acid water in manv mines has greatly increased operating costs. Pumping is expensive and acid mine waters are destructive of all equipment, especially metals in pumps and piping, and necessitate the use of corrosion-resistant materials. Discharge of the acid mine drainage into streams neutralizes their normal alkalinity, causes them to become acid, and produces an environment unfavorable for aquatic life and unsuited for industrial or domestic use without costly treatment. Mine drainages vary in percentage composition over wide limits, although the usual dissolved substances are ferrous and ferric iron, aluminum, calcium and magnesium sulfates, and lesser amounts of sodium, potassium and manganese sulfates and chlorides. Some alkaline discharges may contain heavy concentrations of iron as iron bicarbonate. These waters may produce iron hydroxide deposits in the receiving stream but do not cause it to become acid. In the extensive literature on acid mine water there appears to be a great deal of confusion about the importance of various components and the methods for their determination. In many instances faulty conclusions have been drawn from use of unsuitable methods of analysis. It is desirable that the factors and terms used in evaluation of analyses of mine waters should be so clearly defined that any interested person could properly appraise any analytical report. Some analysts report complete chemical analyses of mine waters and neglect to record drainage volumes. Others report only a minimum of analytical data after taking no precautions to preserve the original composition of the water during the time elapsing between collection and analysis. Some use methods of analysis intended for so-called pure waters of the potable and boiler water classes. These methods are not applicable to highly buffered waters such as mine water. Probably the most common criteria for evaluation are pH, free acidity, or acidity or alkalinity to methyl orange or methyl red, total acidity or acidity to hot phenol-phthalein, and the sulfate content. If these determinations are made on carelessly collected samples after a few days to weeks standing in warm rooms, they do not in any way represent the character of the water flowing from the mines. It is hoped that a brief discussion of the fundamental value of some of these factors may lead to a bettqr understanding of the need for more careful evaluation of mine water discharges. The term pH is one used by chemists to express relative acidity or alkalinity in terms of concentration of effective hydrogen ion in a solution. It is defined as the negative logarithm of the hydrogen ion concentration or activity in equivalents per liter. pH = logarithm A neutral solution, which is one containing the same number of hydrogen and hydroxyl ions, has a pH of 7. As the hydrogen ions increase and the solution becomes more acid, the pH decreases toward zero; and as the hydroxyl ions increase and the solution becomes more alkaline, the pH approaches 14. When dissolved in water to a dilute solution acids like sulfuric and hydrochloric, commonly known as strong acids, ionize completely, and the pH or hydrogen ion concentration varies with molar concentration of the dissolved acid. However, in high concentrations of such acids, the pH or hydrogen ion concentration is less than the acid concentration because the acid does not completely ionize. In only very dilute solutions does the pH represent the total amount of acid that can be neutralized by an alkali. All ionization reactions are equilibrium reactions. If other chemicals are added to the solution of an acid and the added chemical produces an ion that is the same as one of the ions of the acid, the degree of ionization of the acid is altered and the pH changes to some value that represents the active hydrogen ion of the new solution. Thus if iron sulfate is added to a solution of sulfuric acid the pH increases, since the common sulfate ion suppresses the degree of ionization of the sulfuric acid and decreases the effective hydrogen ion. However, the total acidity of the solution is increased. There are two salts composed of iron and sulfate— ferrous and ferric sulfate. In these salts there is no hydrogen ion that can ionize to give an acid solution, but when they are dissolved in water, the pH is less than 7 and the solution becomes acid. This is caused by a reaction known as hydrolysis and is represented by the equations FeSO4 + 2H2O ? Fe(OH)2 + 2H + SO,: or Fe,(SO,)3 + 6H2O ? 2Fe(OH)3 + 6H+ + 3504 A solution with a total acidity of 5000 ppm according to the first equation will have a pH of 4.40 but one with an acidity of 75 ppm, according to the sec-

Jan 1, 1958

By E. R. Gilbert, D. E. Munson

Creep of copper under 75 to 1.50 kg per sq cm stresses at temperatures near the melting point was found to he a complex reaction controlled by three mechanisms acting in parallel. In order of appearance with decreasing temperature, the auerage activation energies, Qc , are 168, 79, and 24 kcal per mole. Stress dependence of the minimum creep rate was found to he an exponential for the two high-Qc processes and a power law for the low-Qc, process. Transition of control occurs from one mechanism to another. The relative transition temperature depends upon the applied stress, and the range oiler which the transition occurs depends upon the difference in the activation energies of the mechanisms. The creep behavior at high temperature is explained by the climb of dislocations through thermally or mechanically formed jogs, CREEP in pure fcc metals at temperatures in excess of one half the absolute melting point is normally controlled by dislocation c1imb.1,2 A climb model which seems applicable, according to an extensive analysis of data,3 was derived by Weert-man.4 This model assumes jog-saturated dislocations and predicts an activation energy, Qc, nearly equal to that for self-diffusion, USd. Although the requirement of jog saturation is restrictive, agreement between theory and experiment seems adequate. Many other theoretical treatments, including an early model by Mott,5 include detailed consideration of jog formation as an initial requirement for climb. These models predict activation energies for creep which differ from those of self-diffusion. Seeger6,7 postulates an observed activation energy related to the stacking-fault energy. Thus, Usd <Qc<5Usd + Uj where Uj is the jog-formation energy. Seeger incorporated qualitatively the influence of the relative numbers of thermal and athermal jogs. Expanding this concept, Shoeck8 explicitly states a function based on formation mode and relative numbers of vacancies: e r ci exp {-uf/k T} exp {-Um/k T} [ 1 ] where Uf and Um are energies of vacancy formation and migration, respectively. The concentration of jogs, Cj, depends upon the manner of jog production. For intersection jogs, Cj is not sensitive E. R. GILBERT, Junior Member AIME, formerly with De- to temperature; for thermal jogs, Cj is proportional to exp {—Uj /k T}. Schoeck regards each mode as a distinct mechanism; therefore, the mechanisms may act together.299 The diversity predicted by theory, surprisingly, has not been substantiated by experimental results. A significant investigation must include the extremes in stacking-fault energy. Extensive creep studies of aluminum10 and nickel,11,12 high stacking-fault energy metals, have been made. Comparable studies on a low stacking-fault energy metal, such as copper, have not. It is the purpose of this paper to report the results of an investigation of the creep of copper under conditions which favor thermal jogs. EXPERIMENTAL Cylindrical compression creep specimens (0.240 in. in diameter by 0.400 in. long) were machined from cold-drawn rods of electrolytic tough-pitch copper containing 0.0007 Mg, 0.002 Fe, 0.001 Ni, 0.0005 Ag, Cd < 0.005, and Pb < 0.005 wt pct impurities. Undetected spectrographically was a nominal 0.04 wt pct 0, which occurs as a Cu2O constituent distributed discontinuously at grain boundaries. Vacuum annealing at 900°C for 15 min produced a stable 0.03-mm average grain diameter. Testing was carried out using apparatus similar to that described by sherby,13 modified by enclosing platens and a push rod in a vacuum cylinder. Normally this arrangement resulted in pressures less than 10 Only a slight surface tarnish, less than 0.0005 in. in thickness, occurred during the test. The applied stress, corrected for atmospheric pressure, was maintained within 2 pct of the desired true stress by the addition of lead shot at fixed strain increments. Creep strain was measured with dial gages as a relative displacement of the upper and lower platens; accuracy of measurement was 0.0001 in. Two creep-test methods were used, the differential or cyclic temperature14 and the isothermal, to obtain creep data at stress levels of 150, 100, and 75 kg per sq cm over the temperature range of 620° to 1032°C. Minimum creep rates were used from both test methods; this was considered proper because comparable temperature tests or cycling to the same temperature gave the same creep rate, within experimental error. The cold vacuum test chamber, with the unstressed specimen in place, was heated to temperature by placing a preheated furnace over the chamber. Temperature equilibrium was attained within 30 min. For the cyclic tests, the stress was removed during the 5 to 10 min necessary to effect the temperature change and re-

Jan 1, 1965

By Anthony J. Chasteen

Although geothermal energy has been used by mankind for thousands of years and has even been used to generate electricity since the turn of the century, it is only in the last few years that the threatened energy crisis has focused attention on this resource. Geothermal exploration and development is being carried out in at least thirty-five countries on five continents. The status of geothermal energy production, however, is rudimentary with about 800 MW installed generating capacity worldwide, equal to about 0.1% of the world&apos;s total energy production.&apos; The world&apos;s first (1904) commercial generating site at Lardarello, Italy, will soon be surpassed by developments at The Geysers, Calif. There are other successfully operating geothermal power projects in New Zealand, Japan, USSR, Mexico and Iceland with pilot plants planned or under construction in Chile, El Salvador, Nicaragua, Turkey and the Philippines. The preponderance of exploration and development is being sponsored or assisted by individual governments, by the UN or by the U.S. Agency for International Development

Jan 10, 1972

By Thomas T., Read

TWO American students entered the Ecole des Mines in 1856, Joseph Lesley of Philadelphia and Thomas Egleston of New York. Lesley remained there only one year, but Egleston completed the whole &apos;curriculum and received, in 1860, the certificate given to foreign students .in lieu of the official appointment and degree. awarded French students. Returning home he received, in 1861, an appointment by Secretary Henry of the Smithsonian Institution to sort, label, and arrange the collections of mineralogical and geological specimens which had been brought to Washington by the various government exploring expeditions in the West. Thomas Egleston, born in New York City on Dec. 9, 1832, was the son of Thomas Jefferson Egleston, who came to New York from Massachusetts some time before 1829. The first American ancestor of the family had settled near Dorchester. in 1630. T. J. Egleston and Joseph Battell established an iron-merchandizing business* at 166 South St., New, York, which prospered exceedingly; so much so that when Thomas J. Egleston died, July 12, 1861, his estate had a book value of over $500,000. Since an older brother was expected eventually to take over this business, Thomas, who had a liking for science, went to Yale,, where he completed the regular four-year course in 1854, and then remained another year for advanced work in chemistry under Silliman. I One biographer says he went to Europe, . early in 1-856, on account of his health. It was the custom at that time for wealthy young men to make a tour of Europe after completing their academic education. Whatever the precise reason, he began scientific work at the Jardin des Plantes in Paris but soon trans* It still operating as Egleston Bros. Inc., though no direct descendants of its founder are now living.

Jan 1, 1941

By H. R. Green, D. M. Lamb, A. D. Taylor

The design of slurry launders has usually been based on strictly empirical concepts. An examination of the most common procedures reveals that they do not account for many of the variables that are recognized as significant for slurry transport. These may include flow rate, volume concentration of solids, solids specific gravity, solids size distribution, particle shape, launder geometry, and roughness of the wetted surface. It was decided to develop a design procedure, which would accomplish two things: First: Take into consideration most of the known significant variables and systematize the procedure to assure consistent results. Second: Provide a rational basis for examining and utilizing operating data to refine and improve the system. To accomplish this, it was necessary to develop a basic design concept. This concept has been developed through a complex development history, and yet still appears workable and technically sound. That concept may be outlined as follows: First: The solids transport velocity is the fundamental basis for slurry launder design. Second: The stream configuration, hence the launder size, is integrated with the solids transport velocity so that the actual stream velocity exceeds the solids transport velocity. Third: The launder slope is that which will achieve the

Jan 1, 1979

Payloader The Frank G. Hough Co. has made available another four-wheel drive tractor-shovel. It has a 1 cu-yd bucket with 60 hp Diesel or 54 hp gasoline power optional. The use of large pneumatic tires, same size all around, and drive on all four wheels gives this new Payloader traction to work effectively in sand, mud and snow, and travel on pavements with- [ ] out injuring the surface. Rear wheel steer with power booster plus short wheel base makes it easy to operate and highly maneuverable. Four speeds in both directions insure fast travel speeds for transport and fast operating speeds on shuttle loading or similar operations. Bulldozer blade, crane hook, fork lift and snow plow attachments are available, quickly interchangeable with the bucket to further increase its multi-purpose usefulness. Circle No. 1

Jan 1, 1952

By J. A. Rowland, C. W. Funk

THIS investigation is a part of the United States Bureau of Mines work in conserving the Nation&apos;s resources. The isothermal sections presented were developed as a guide to a comprehensive investigation of the properties and fabricating characteristics of copper-base alloys containing manganese and tin. These alloys are being investigated as possible replacements for the commercial bronzes containing substantial quantities of tin. Development of the isothermal sections has, therefore, been limited to the area between 0 to 20 pct Mn and 0 to 25 pct Sn. Since Heusler1 reported the ferromagnetic properties of the Cu-Mn-Sn alloys in 1903, the system has been the subject of several investigations. These studies were largely concerned with correlation of magnetic properties and crystal structure.2-6 Vero,&apos; however, established the solidus surface of the system, between 20 pct Mn and 40 pct Sn, by thermal and microscopic methods. The a, ß, and y solid solutions were also observed by Vero and reported to extend into the interior of the ternary system. For the present study, the annotated diagram of the Cu-Sn system prepared by Raynor&apos; and the Cu-Mn diagram by Dean and coworkers9 were used as the binary borders of the ternary system. Procedure The metals used in this investigation were electrolytic manganese, washed cathode copper, and three-star tin. The manganese, produced at the Boulder City pilot plant of the Bureau of Mines, had a purity of 99.9 pct; the copper contained less than 0.004 pct Bi and 0.001 pct S; the tin contained 0.070 pct Pb, 0.070 pct Sb, 0.050 pct Fe, and 0.065 pct Si. Heats of 1 lb were melted in alundum crucibles with a 3-kw induction furnace. The heats were chill-cast in iron or copper molds to form 6-in. ingots 3/4 in. in diameter. Molds were washed with graphite or zirconia, depending on the manganese content, and preheated to 150°C. The maximum impurity content of any alloy was 0.03 pct Fe, 0.02 pct Si, and 0.02 pct Al; in most cases, they contained less than half this quantity of any of these impurities. Composition of the alloys and their treatment prior to homogenizing are shown in Fig. 1. Designations adjacent to each composition refer to the heat numbers. With a few exceptions, ingots containing 20 pct Sn or less were hot-swaged. These ingots were swaged, after a 24-hr preheat at 650°C, to obtain a total reduction of 70 pct in cross section. Intermittent reheating was necessary, and reductions were limited to either 0.025 or 0.050 in. in diameter per pass. Selection of a 200-hr homogenizing treatment was based on extensive experiments which indicated that virtual equilibrium was reached after 150 hr. Structures were retained by quenching in water. Grain sizes in the specimens homogenized at 350" and 450°C were generally small. These homogenizing treatments were preceded by a 50-hr anneal at 650°C to facilitate phase identification by increasing the grain size in these specimens. The specimens were furnace-cooled from this temperature to the homogenizing temperature, and the heat treatment was continued for the standard 200-hr period. The homogenized samples were bisected to provide an internal section for metallographic examination. Optimum definition of the microstructure was obtained by successive polishing and etching. Quarter-strength ASTM copper reagent No. 13 gave the most satisfactory results.10 Filings from interior sections of the samples were used for diffraction studies. These filings were annealed in evacuated glass tubes at homogenizing temperatures for periods exceeding 50 hr and quenched in water. During this treatment the manganese content was reduced by significant amounts, probably by vaporization. This change in composition was considered in applying the diffraction data, which were used only as a means of identifying phases where the data were consistent with the metallographic evidence. Phase Identification The a solid solution is readily distinguished by the copper-colored, twinned, polyhedral grains, as shown in Fig. 2, and a face-centered cubic X-ray pattern. Tukon indentations, using a 25-g load, indicate a Knoop hardness of 155 for a quenched from 650°C. Using white light developed by a Wratten 78 A filter, the ß grains in etched specimens have a dark brown tint in contrast to the lighter copper-colored grains of the a phase. Knoop hardness values of 284 were obtained for the ß structure in specimens quenched from 650°C. The ß structure was also distinguished from the a phase by its body-centered cubic lattice. The acicular structure appearing in Fig. 3 was evident in several alloys of higher tin content after quenching from either 750&apos; or 650°C. Since a trans-

Jan 1, 1954

By Ernest Gayford

This is a nontechnical paper on flotation, subdivided under three general headings: (I) Definition of flotation; (2) what flotation is now doing in Utah; and (3) what is the future of flotation? Definition T. A. Rickard defines flotation&apos; as "the act or state of floating," from the French flottaison, water-line and flotter, to float. The dictionary defines flotation as "the science of floating bodies." The flotation process is a method of concentrating ores by frothing. Weinig and Palmer,2 define flotation as follows: What is the flotation process? Briefly, it consists in the agitation of finely divided ore in water containing bubbles of air or gas, a small amount of oil and, usually, other reagents, soluble and insoluble; under these conditions the small particles of native metals, sulfides, arsenides, antimonides, selenides and tellurides show a tendency to attach themselves to the films of the bubbles, and are thus carried to the surface of the water. The oxidized gangue minerals, such as quartz, feldspar, limestone, hematite, etc., show much less affinity for the bubbles, are easily wetted by the water, and either remain in suspension in the water, or sink to the bottom of the vessel. If the bubbles are sufficiently stable they can be removed, carrying their load of sulfide-mineral particles with them. Thus there can be effected a separation of the two classes of minerals from each other, assuming that the grinding has been sufficient to unlock all of the particles of different composition. The separation does not depend upon differences in specific gravity of the various minerals; in fact, the sulfides are usually heavier than the oxides, and some of the heaviest sulfide minerals are the easiest to float. A particle of mineral may be so large, however, that its weight will counteract its affinity for the film of the bubble. In most cases the ore must be fine enough to pass a screen having at least 48 meshes to the linear inch. Taggart3 defines flotation as follows: Flotation is a method of wet concentration of ores in which separation of mineral from gangue is effected by causing the mineral to float at or above the surface of a body of liquid pulp while the gangue becomes or remains submerged. The method

Jan 1, 1928

By Kirtley F. Mather

FROM almost every point of view, petroleum was "strategic mineral number one" during the World War that ended in 1945. Even the spectacular advent of the atomic bomb in the final days of the conflict did not displace it from its position of prime importance, although within a few years uranium will almost certainly be the "number one" material in the minds of military strategists, if it is not even now in that position. But both as fuel and as raw material for chemical industries, petroleum will hold the center of the stage for many years to come. Hardly any other substance illustrates so fully the manner in which science and technology may be combined to achieve the utmost success in contributing to human efficiency and comfort. Fundamental to any understanding of the problems implied by my topic

Jan 1, 1948

By Anthony Lucas

THE discovery of oil in 1901 on the Spindletop dome, Texas, inaugurated a new industry on the Gulf Coast, an industry which has grown with the discovery of successive fields, until today it engages the services of thousands of workers and employs enormous capital. New fields are being discovered from time to time and doubtless some still remain to be found, though of late years discoveries have become more infrequent. Nowadays several hundred dry holes are drilled each year in a fruitless and blind effort to discover new fields, for as yet geologic science has developed no effectual method of locating the coastal oil deposits in advance of drilling. Moreover, despite the occasional discovery of new fields, the total production of the Gulf Coast is today no greater than it was in 1906, for the added production of the new fields has been offset by the rapid decline and more or less complete exhaustion of some of the older ones. Careful geologic work within the fields has in some cases increased the production temporarily, but has developed no really new supplies. The Gulf Coast oil industry seems to have passed its period of greatest expansion and to be declining at a fairly steady rate, and this condition is naturally viewed with alarm by the more farsighted operators. In my opinion, the time has come for the adoption of radical and aggressive methods of prospecting, and a fraction of the money wasted yearly in drilling shallow wells in hopeless locations might well be devoted to this purpose. Many facts lead me to believe that all the salt-dome oil has had a common origin; that it has migrated up from considerable

Jan 7, 1918

By Denton R. Wieland, Harvey T. Kennedy

The frequency of bubble formation is measured for oils from the East Texas field and the Slaughter field in cores from these fields. East Texas oil was also tested in a Slaughter core. The data checked previous results in that a definite supersatrtration may exist without the formation of bubb1es in periods of observation totaling 158 hours. Measured frequencies varied from zero at supersaturations below 14 psi to 3.1 bubbles/sec/ cu ft of rock at 40 psi supersaturation INTRODUCTION The formation of bubbles is essential in a solution gas-drive reservoir in the displacement of oil. In formations where the basic pore structure consists of fine pores or fractures connected to larger pores or crevices, bubble formation in the fine pores may be the most effective means by which the oil may be displaced, even if secondary methods are applied. The most efficient oil displacement would occur where at least one bubble would form in every pore. As the pressure decreased, the bubbles would expand, due to the gas diffusing into the bubbles, and displace the oil toward the lower pressure area around the wellbore. Kennedy and Olson&apos; have shown that the total number of bubbles formed in a reservoir is primarily dependent upon the rate of pressure drop, the rate of diffusion of gas through oil, and surface area of the rock. The surface tension of the liquid and other characteristics of the rock may also exert an important effect, which would give a different frequency to different rocks and oils and various combinations of different rocks and oils. The purpose of this paper is to present frequency measurements on two rocks and two oils. A hydrocarbon liquid is at equilibrium with gas when it contains the maximum volume of gas in solution that it can have at the prevailing temperature and pressure. If the temperature is maintained constant and the pressure is reduced below the equilibrium pressure, the liquid is supersaturated to the extent of the difference in the two pressures until the gas comes out of solution as a free phase. As shown by previous work, and confirmed in the present investigation, the number of bubbles formed per second increases with an increase in supersaturation. Kennedy and Olson showed that a tenfold increase in the rate of pressure decline resulted in a tenfold increase in the number of bubbles formed per cubic foot of reservoir rock, e.g., for decline rates of 0.1, 1, and 10 psi/day, the number of bubbles formed per cubic foot would be 40, 400, and 4,000, respectively. For another hypothetical system, Stewart, Hunt, and Berry&apos; estimated that for pressure declines of 0.1, 1, and 10 psi/day, the number of bubbles formed would be approximately 10, 100, and 1,000 cu ft of reservoir rock. Their value of bubbles formed is lower than given by Kennedy and Olson; however, the order of magnitude agreed satisfactorily. The rate of diffusion will also affect the number of bubbles formed. If the diffusion coefficient is high, the gas in solution in the oil surrounding a single bubble will tend to diffuse into the bubble rather than forming other bubbles. On the other hand, the formation of more bubbles will tend to occur if the diffusion coefficient is very low. In his thesis dated Aug., 1953, Wood" reports on the frequency of bubble formation in a system consisting of oil and rock from the Rangely field. In the present work, the apparatus of Wood was redesigned to allow greater precision, especially at low supersaturations, where bubble growth is slower, and detection is more difficult.

Jan 1, 1958

By Arthur Notman

IN VIEW of the wide publicity given to the charges by the Couzens Committee of the United States Senate of discrimination by the Bureau of Internal Revenue in favor of the copper companies, it becomes a matter of interest to consider the basis for these charges. The point to be determined is whether they rest on a foundation of fact or are purely and simply matters of opinion. The whole question boils down to the purpose of the Tax Law as applied to mines, which is to afford the same protection to them as provided for all other taxpayers, namely: that they were to be allowed to pay back as depletion to their owners the values of their properties as they existed or were estimated to exist on May 1, 1913, free from tax. To determine these valuations it was? necessary to select from a wide range of possibilities a set of values for a number of essential factors.

Jan 1, 1925

By Fred D. DeVaney and

The coercimeter, as its name implies, is an instrument for measuring the coercive forcet of magnetic substances. It was developed by Davis and Hartenheim in the Special Studies Section, Metallurgical Division. A detailed description of this apparatus may be found elsewhere.2 The coercive force determinations of magnetic materials are interesting because of the relationship established by Gottschalk,4 who showed a linear relationship between the magnetization coercive force and the specific surface of comminuted particles. The value of this relationship in determining grinding efficiency has been shown by Dean.3 The determination of the surface contained in the subsieve sizes has always been a difficult problem for investigators. They made approximate measurements of the surface of coarse materials by sizing on screens, but for the determination of the surface of the sub-sieve sizes it was necessary to make detailed grain counts or elutriation tests, or to study dissolution rates. The technical literature contains many references to other methods for determining these surfaces, either by some special apparatus or by mathematical calculations based on distribution lines. Many of the methods are long and tedious, and the results of some, at least, are questionable. he turbidimeter gives quick results on ground cement. By using magnetite as the material to be ground, a simple determination of its coercive force by the coercimeter, requiring 10 minutes or less, can be transposed directly and accurately into units of relative surface. This subject has been pursued further by the U. S. Bureau of Mines in cooperation with the Missouri School of Mines and Metallurgy, Rolla, Mo., and the following is a description of the results.

Jan 1, 1939

By Fred D. DeVaney and

The coercimeter, as its name implies, is an instrument for measuring the coercive forcet of magnetic substances. It was developed by Davis and Hartenheim in the Special Studies Section, Metallurgical Division. A detailed description of this apparatus may be found elsewhere.2 The coercive force determinations of magnetic materials are interesting because of the relationship established by Gottschalk,4 who showed a linear relationship between the magnetization coercive force and the specific surface of comminuted particles. The value of this relationship in determining grinding efficiency has been shown by Dean.3 The determination of the surface contained in the subsieve sizes has always been a difficult problem for investigators. They made approximate measurements of the surface of coarse materials by sizing on screens, but for the determination of the surface of the sub-sieve sizes it was necessary to make detailed grain counts or elutriation tests, or to study dissolution rates. The technical literature contains many references to other methods for determining these surfaces, either by some special apparatus or by mathematical calculations based on distribution lines. Many of the methods are long and tedious, and the results of some, at least, are questionable. he turbidimeter gives quick results on ground cement. By using magnetite as the material to be ground, a simple determination of its coercive force by the coercimeter, requiring 10 minutes or less, can be transposed directly and accurately into units of relative surface. This subject has been pursued further by the U. S. Bureau of Mines in cooperation with the Missouri School of Mines and Metallurgy, Rolla, Mo., and the following is a description of the results.

Jan 1, 1939

By Frederic Dewey

HAVING shown1 the difficulty of assaying so-called cyanide bullion and the extreme variations often found in the results, an investigation was undertaken to discover if possible the causes of these variations by a series of tests upon the specific action of various metals during cupellation. Zinc.-In order to test the effect of zinc, 48 assays were made in sets of 6, 2 rows of 3. The charge for the middle cupels consisted of 500+ mg. Au, 1,125 mg. Ag, 10 mg. Cu. To the end cupels 50, 75, 100 and 125 mg. Zn were added, and a set of each proportion was cupelled with 4 and 8 grants Pb. The cupels were assayed and showed the following gold contents in milligrams, the figures being arranged as the cupels stood in the muffle: TABLE 1 50 Mg. Zn 75 Dig. Zn 100 Mg. Zn 125 Mg. Zn 4 grams, Pb 0.2S 0.25 0.2S 0:29 0.27 0.34 0.33 0.28 0.41 0.31 0:30 0.36 0.30 0.33 0.34 0.31 0.31 0.29 0.35 0.37 0.42 0.41&apos; 0.34 0.38 8 grams, Pb 0.40 0.43 0.42 0.38 0.36 0.43 0.35 0.34 0.41 0.33 0.37 0.37 0.54 0.17 0.59 0.44 0.43 0.43 0.38 0.39 0.41 0.57 0.38 0.46 _ In many instances the zinc does not appear to affect the cupel gold, but various exceptions are apparent, generally in the cupels in the back row. With 100 and 125 mg. Zn, in some cases the Zn burned with its characteristic flame before it could alloy with the other metals. Also, less fusible oxidized lumps were observed during the cupellation and some cupels showed a scum. In order to lessen the premature burning out of the Zn, an alloy of 2 parts Ag to 1 part. Zn was used. A uniform charge of 500,+ mg. Au,

Jan 7, 1917

By R. E. Phelan

WHILE 1931 was a most important year in the history of Canadian copper smelting and refining, nevertheless, due to the low price of copper and the in- ability of the International Nickel Co. to market its full capacity of nickel. the production of both copper and nickel was considerably less than the total installed capacity for the production of these metals. IIY the nor- mal course of events, 1931 should have seen a great increase in the production. of both copper and nickel in Canada, because the large extensions to both the copper smelting plants and the copper and nickel refinery capacity, which had largely been completed in the year 1930, should be showing their effect.

Jan 1, 1932

By W. H. C. SIMMONDS

The mining, metallurgical, and petroleum industries can be viewed as financial or as social institutions or both. The differences between these two conceptions of their businesses will influence their environmental &apos;and social actions. During the next 10-20 years western industry will be subject to a drop in the growth of a more highly educated labour force and to the emergence of holistic economics, new national goals, and a new ecological perspective. The profitability of the mining industry may therefore be influenced by the human side of its business to a greater degree. The increasing human, social, and environmental responsibilities can be discharged by improving the miner&apos;s equipment; by learning to look at situations through the eyes of all those involved; by developing common &apos;languages&apos; which governments and the public can understand; and by mediating where feasible on the international scene.

Jan 1, 1978