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By G. D. Van Arsdale

THE paper of Mr. Posnjak presents a laboratory confirmation of the well known facts that air ox-idation of pure solutions of ferrous sulfate is slow and difficult and that, like many other similar reactions, the speed, may be greatly accelerated by the presence of other substances, often in very small amounts, the effect of the presence of copper being determined ex-perimentally in this case. However, it should not be. overlooked that copper is always present in heap leach-ing solutions in amounts equal to or greater than those in the experiments described; therefore the paper may be considered as an explanation of present results rather than a possible improve-ment to be added to present practice. It is not practicable and it does not pay to precipitate copper by ce-mentation below a point about 5 lb. per 1000 gal., equivalent to about 0.0005 mol. Cu. per liter, compar-ing with the approxi-mately 0.0009 mol. per liter of curve 2 in the diagrams given of course, also, in the heaps local concentrations are usually very much higher than this, which is also true of the effluent li-quors, so that I feel that it is safe to say that copper is already present in amount sufficient to realize, as large an accelerating effect as is practicable. Too much im-provement or refinement cannot be expected in a method of this kind, due to commercial limitations. It should be remembered that chemically and physically there is no sharp dividing line between leaching in place, heap leaching, and the usual tank leaching practice, practi-cally the same reagents being used in all three. From the viewpoint of extractions, etc., it is not common sense to apply leaching in place to an orebody carrying enough copper to pay for mining; and the same is true of heap leaching, for an ore carrying enough to pay for the crushing, handling, etc., of ordinary leaching. That is to say, leaching in place should properly be consid-ered only for an ore too low-grade to pay for mining, and heap leaching for the next higher grade, still how-ever too low-grade to pay for crushing and other re-finements. There is no advantage in leaching without mining or in heap leaching except lower cost of in-stallation and handling; on the other hand there are very distinct disadvantages which are inherent and which should prohibit their use except where necessity requires. The object of metallurgy is to make money out of the handling of ore, and it is purely a question of money as to how far we can go in "improving" or

Jan 7, 1927

By R. H. Hiltz, N. J. Grant

Solid-solution titanium-cerium alloys, cold-rolled to 0.010 in. thickness, and annealed, were internally oxidized to produce a fine dispersion of CeO2 in the titanium matrix. The oxidized alloys were cut into sheet stress-rupture specimens and tested for rupture life at 426°C, 538°C, and 648°C. There was noted an improvement in strength over that of pure titanium, the internally-oxidized alloys showing curves with a much flatter slope on the log stress—log rupture life plot, characteristic of the stable metal-metal oxide class of alloy. DURING the past 3 to 4-year period, considerable interest has been aroused by the potential offered by alloys based on the ultra fine dispersion of a hard insoluble phase in pure metals or solid-solution alloys for use at high temperatures. The impetus to the development and study of such alloys was provided by Irmann.1,2 through the success of the SAP alloy (pure aluminum containing about 12-14 volume pct of A12O3). Subsequent studies have thrown light on the true potential of this class of alloys in the remarkable stability of the structure after long-time exposure at high stresses and high temperatures.a-5 While success has been demonstrated in the special case of the A1-Al2O3 alloys, and more recently

Jan 1, 1959

By John McCoy, Edward Thimons, Kenneth Heller

As the working levels in domestic mines are developed to greater depths and work areas move further from the shafts, maintaining a safe and healthful working environment becomes more difficult. Increased temperature and humidity at greater depths becomes first a factor in productivity and then a threat to the miner's safety. Initially, a miner might develop listlessness leading to reduced productivity and reduced alertness. Continued overexertion can lead to heat stroke and possibly death. Mine ventilation engineers, therefore, must not only provide clean air to work areas, but also must provide cooled air. The following article describes the United States Bureau of Mines (USBM) and Foster-Miller's successful development of a high performance, low maintenance direct water to air contact heat exchanger for mine cooling. While heat problems frequently do not develop until mining operations descend below sea level, problems will arise any time mining penetrates high temperature rock. Hot fissure water will increase the severity of the situation, causing increases in wet bulb temperature - the temperature to which perspiring miners reject metabolic body heat. All energy expended in mining adds to the heat load which must be absorbed by the ventilation air. Just when the cooling capacity of ventilation air is needed most, adiabatic compression (autocompression) of air descending the shaft raises air temperatures 1.3g°C (2.5'F) to 2.94"C (5.3OF)/305m (1000 ft) depending on humidity. Increased temperatures decrease the ability of the air to absorb heat from the mine, and work area temperatures rise. Once forced ventilation air can no longer maintain safe work area temperatures, refrigeration methods must be employed. Many mines now use cooling coils for this purpose. A cooling coil uses refrigerated mine water to cool the air by passing the air through banks of copper tubing filled with cold water. Heat from the air is transferred to the water through the pipe with the aid of fins. Conventional water to air heat exchangers prove troublesome for many mines be- cause of the high levels of dust that are encountered, causing these exchangers to operate at relatively low efficiencies. A more satisfactory approach to work- place cooling is desired - one that offers reduced maintenance and increased cooling efficiency.

Jan 1, 1982

By R. S. Christie

Reservoir pressure is the pressure at which a fluid is held in a state of equilibrium in a porous stratum. This pressure may be a result of the genesis of oil or gas and its subsequent migration into and through an adjacent porous stratum, or of hydraulic head. Reservoir pressure is an indication of the potential energy contained in the reservoir, and when it is known the engineer is in a position to use it to advantage in recovering and lifting the oil. It is important to know the pressures in any type of reservoir, but this knowledge is probably of greater value in a limestone reservoir, as at Hobbs, where producing rates or conditions may be more sensitive to changes in pressures. The Hobbs field is in east central Lea County, New Mexico. The discovery well was completed by the Midwest Refining C I. in 1928, but intensive development did not begin until after the completion by the Humble Oil and Refining Co. of No. 1-A Bowers in February, 1930. There are 143 producing wells on approximately 5500 acres. The field has not been defined to the northwest, but a projection of structural contours indicates that the productive area ultimately may cover 7500 acres. The producing horizon is the White or Crystalline lime of Permian age. The top of the lime is found at an average depth of 4000 ft. and the wells penetrate it an average distance of 200 ft. The main pay zone is an oolitic stratum about 25 ft. below the top, and varies from 2 to 15 ft. in thickness. Other porous or cavernous strata are found lower in the lime but have little saturation. The initial production varied from 100 to 25,000 bbl. per day, depending perhaps to some extent on the structural location but chiefly on the porosity of the pay. The initial gas-oil ratio varied from 325 to 16,000 cu. ft. per barrel. In wells where the top of the White lime was found below 350 ft. below sea level (Fig. 1)) the gas-oil ratio was usually less than 1500 cu. ft. per barrel, while in wells higher than 350 ft. below sea level, the ratio was usually above 2000 cu. ft. per barrel. The water table has been determined at about 620 ft. below sea level, by three wells on the west side of the field. With few exceptions, the wells have been completed with 7-in. casing cemented

Jan 1, 1932

By Albert E. Reed

THE development of the modern high-speed vibrating screen, together with the increasing availability of long-lasting stainless-steel screen cloth for relatively fine-mesh separations, means that more screen circuits will be used in the future. It seems pertinent therefore to examine a few characteristics of screen-circuit products, and especially the points of difference as compared with products of classifier circuits. The most noticeable change that takes place when substituting screening for classification in a grinding circuit is a substantial drop in the circulating load, owing to the greater ease with which the "fines" leave the circuit. Where circulating loads of 500 to 600 per cent are considered fairly normal in classifier grinding circuits, the grinding circuit equipped with screens for equivalent work will have a circulating load of only 20 to 75 per cent. As a result, the products of screen circuits will show a minimum of overgrinding or sliming as compared with a classifier circuit. The desirability of this characteristic will naturally vary according to the metallurgical requirement in each case. Because screen separations make a sharper division according to particle size, the products of screen circuits can be expected to show greater crowding of particles near the point of separation. These changes in product characteristics are so important that other factors, both in the grinding and concentration processes must be adjusted if the operator is to take full advantage of the increased tonnages and higher efficiencies available to him through the use of the screen circuit. One factor that too often is overlooked when changing to screen circuits is the importance of adjusting the ball-mill or rod-mill charge, to compensate for: (I) increased tonnage of new feed, (2) decreased circulating load, or (3) more granular character of feed. These same factors should also be taken into consideration for their effect on the various types of concentration or flotation equipment that may follow the screen circuit. Over a period of years, this equipment has generally been designed and adjusted to the product of the classifier, therefore it seems obvious that some research on the adjustment and adaptation of concentrating and flotation equipment to screen-circuit products will be most profitable to the operators. To illustrate the points mentioned above, the results from three recent installations follow, with data on the comparative characteristics of screen and classifier circuits. A range of separation from 10 to 48 mesh has been chosen, using two general types of screening equipment and two types of classifiers. The first of the installations of which the results are to be examined is that of an iron-ore installation where eastern magnetite was being concentrated prior to sintering. Fig. I shows the original grinding circuit, using classification, while Fig. 2 shows the same circuit equipped with a

Jan 1, 1945

By E. C. Truesdale, R. K. Waring

THE Research Division of The New Jersey Zinc Company (of Pa.) has conducted, over a period of years, numerous tests of the reducibility of various zinc ores and the reactivity of various kinds of coal, using a number of different experimental methods. Most of these tests have involved the reduction of mixtures of ore and coal. In such cases the following simultaneous reactions are believed to be mainly responsible for the production of zinc, as was shown by Bodenstein1 some years ago: ZnO + CO = Zn + CO2[I] C + CO2 = 2CO[2]. Each of these reactions is dependent upon the other for the supply of CO and C02, respectively, and the over-all rate of formation of zinc vapor will be determined by the slower of these two reactions. An analogous pair of reactions sometimes of importance is: ZnO + H2 = Zn + H2O[3] C+ H2O=CO+H2[4] While it is possible to obtain an indication of the relative reducibility of various ores, or of a fine versus a coarse ore, by testing them with a given coal, and while coal reactivities may be measured in a corresponding manner, a more direct determination of relative reaction rates is possible by carrying out the desired reactions, such as I and 2, separately and under reproducible conditions. It is one purpose of this paper to present some of the results that have been obtained by the latter method. C. G. Maier2 discusses the relative rates of reactions I and 2 and concludes that while at relatively low temperatures reaction I is faster than reaction 2, this difference becomes less with increasing temperatures, although at smelting temperatures reaction I is still the faster. He also says (p. 48), "At temperatures . . . between 1100° and 1300°C the zinc oxide reduction reaction is intrinsically more rapid than its physical limitations; that is, it is limited by gas diffusion rates." In the course of numerous reactivity tests involving the separate use of reactions and I and 2, we have obtained data that show by direct experiment, we believe for the first time, the correctness of Maier's statements concerning these reactions. We also include data on the relative rate of reaction 3, involving reduction by hydrogen. Finally, some interesting results obtained by carrying out the reduction of a zinc ore-coal briquet in streaming atmospheres of nitrogen, carbon monoxide and hydrogen, respectively, are presented.*

Jan 1, 1941

By Edward Steidle

It has been said that "the command of nature has been put into the hands of man before he knows how to command himself," and what we see about us gives particular emphasis to this observation. If this condition be granted, the vaunted boast of school and college, of the institution that had the training of this generation, and of its fathers, and of its grandfathers, the boast that education is a "preparation for life," stands exposed as a hollow claim, or as a ghastly, cynical conception of life, or else education has fallen far short of its intentions. It has been evident for some time that education was not meeting the fullest expectations of society. In recent years there has been a deal of speculation indulged in by both laity and faculty in regard to American education and American civilization, and some few and sporadic changes have been effected. Today, however, there is no longer time for mere hypothetical considerations; we are faced with certain definite facts and confronted with obvious conditions that will not wait for fine-spun theories. If educators do not put their house in order, someone else will do it for them. The trends in mineral industries education must be in harmony with this general realignment that is today visible on the educational horizon, and only as these trends are in conformity with this movement can they be called sound. Two questions, then, confront mineral industries educators: (1) What are the trends in mineral industries education, and (2) how do these trends correlate with the major educational movements of the day? Scope or Mineral Industries Education Before launching into these particulars, it might be well to define the scope of mineral industries education and to consider its present position. Mineral industries education embraces three main types of work: 1. Earth Sciences and Geography.—Geology, mineralogy, geography— courses basic to all mineral industries and to the humanities. 2. Mineral Engineering.—Mining, petroleum and natural gas—dealing with mineral producing industries. Application of earth sciences and all types of engineering to exploitation of natural mineral resources.

Jan 1, 1934

By John E. Miller

Unit Rig & Equipment Co., manufacturer of Lectra Haul trucks, is continually studying methods of reducing the operating costs of large haulage trucks. Reduction of haulage system operating costs is an important goal that equipment operators and equipment manufacturers constantly try to improve on. One of the most variable and important factors affecting operating costs is actual truck operating practices. An examination was centered on methods to optimize truck utilization. It was found that a very effective method of accomplishing this goal would be an automatic truck control (ATC) system to automatically control a fleet of haulage trucks in a predetermined pattern. Economic studies were conducted which showed a very favorable reduction in mine operating costs by use of an ATC system. In 1970, Unit Rig & Equipment Co., in conjunction with SAAB-SCANIA began preliminary development of adapting, for truck use, a proven automated control system, previously used for train systems, small trucks, and military target vehicles. In 1974, the first prototype system was installed on a Lectra Haul M-100 and tested extensively at Unit Rig's test track in Tulsa, OK. This truck and system were then displayed publicly at the 1974 convention in Las Vegas. In 1976, the system was redesigned for production to maximize reliability, ease maintenance, and to accommodate future control and-status reporting developments proposed for haulage trucks. The new design equipment was manufactured, and a full system test will be conducted in an actual open-pit mine for an extended period to evaluate reliability, compile economic data, and obtain application information to evaluate complete mine haulage system conversions to ATC. System Description The ATC system is designed to provide automatic control of all the vehicle functions normally accomplished by the vehicle operator. The basic system consists of the on-board control equipment and the wayside control equipment. The on-board equipment receives commands from the wayside equipment and controls all the truck functions. In addition, on-board sensors monitor all critical truck functions and provide instructions to the truck and system to assure safe operation. The wayside equipment consists of a buried guidewire, block control units and a central controller which provides predetermined signals to the on-board equipment for speed control, steering, and for auxiliary functions (dumping, horn, etc.) through the guidewire located in the truck's path. The wayside equipment also controls vehicle separation, system status, and provides truck location to a central display panel. The central control panel can vary the speed level signals over any segment and can also command an emergency stop to halt all the units. [Fig. 1] illustrates a typical ATC installation. If ATC is used in operations which require flexibility and mobility at the end of the ATC guidance network, the trucks can then be operated by either radio remote control or manually to complete their assigned functions.

Jan 1, 1982

By T. N. McVay, E. E. Creitz

INTRODUCTION Object RATHER large amounts of titanium minerals and some zircon and monazite are being recovered from dune sands about 10 miles west of Jacksonville Beach, Fla. The Mining Branch of the Bureau of Mines, Southern Experiment Station, has been interested in developing additional large deposits of similar sands in other areas of Florida. The results of a field study have been published1 concerning the sands occurring on Trail Ridge which runs north and south about 30 miles southwest of Jacksonville. This investigation was undertaken in order to identify the opaque titanium minerals occurring in Trail Ridge and because of the economic importance of Florida titanium minerals. Nature of the Problem The minerals present in the heavy fractions (sp gr > 2.94) of the sands are principally opaque minerals; staurolite, zircon, sillimanite, tourmaline, kyanite, rutile, a small amount of corundum, traces of the zinc spinel gahnite and garnet. Epidote, monazite, hornblende and titanite are present in other dune sands but these minerals were not noted in the samples collected on Trail Ridge. All of the minerals except those which are opaque can be readily identified by the usual petrographic methods. However, opaque minerals cannot be examined satisfactorily by transmitted light. Polished sections of the opaque-mineral grains were examined but these sections did not furnish useful information. Consequently, it was necessary to use means other than the usual petrographic methods to identify them. Previous Investigations of Heavy Minerals in Florida Sands Martens2 has described the heavy minerals in the Florida beach sands and has classified the opaque minerals as ilmenite with minor amounts of leucoxene. Miller3 studied a number of sands collected by Ross and Mertie in Florida. He states that the material from the Florida beach and dune sands that commonly has been called ilmenite has essentially the chemical composition of the material that has been called arizonite.4 The X ray diffraction patterns of several samples indicated that the supposed ilmenite is essentially amorphous, with only weak lines corresponding to ilmenite, and hence the material is unlike the type of arizonite from Arizona. Opaque Titanium Minerals Rutile is essentially titanium dioxide. However, as pointed out by Dana,5 important amounts of Fee and Fe3 as well as Cb and Ta are reported in some analyses.

Jan 1, 1947

By W. F. Hosford

A quantitative explanation is offered for the peculiar curled grain shapes found in the microstructures of drawn wires of bcc metals and compressed aluminum specimens. It is shown that once an [011] fiber texture is developed, the slip system are so oriented that further slip tends to produce plane strain rather than axially symmetric flow of individual grains. With plane -strain flow, however, compatibility of neighboring grains can be maintained only by a bending of grains about one another. PROBABLY the most obvious microstructural feature of heavily worked metals is the distorted shapes of grains. In the course of deformation, the shape change of each grain must be compatible with that of neighboring grains; otherwise holes would be formed at grain boundaries. In analyses of poly-crystalline deformation by Taylor and subsequent workers it was assumed that grain boundary compatability was maintained by each grain undergoing the same shape change as the polycrystalline aggregate in which it is imbedded. According to this assumption, when simple tension or compression is applied to a random polycrystal or to one with a fiber texture, each grain ought to deform with axially symmetric flow. Initially equiaxed grains should become cigar-shaped during wire drawing and pancake-shaped during compression. While microstructural observations of deformed metals are generally in accord with such a picture, certain striking exceptions may be noted. Peck and Thomas5'8 found that grains in heavily drawn tungsten, iron, and niobium (columbium) wires become shaped like ribbons curled about the wire axis, Fig. 1. At a suggestion from the author, they rationalized the development of these micro-structures by considering the orientation of the slip systems in the [011] texture formed by the wire drawing. It is shown in this paper that marked departure from axially symmetric flow of grains is also observed when polycrystalline aluminum is severely compressed. Again the explanation must lie in the orientation of the slip system in the [011] texture, which is formed in fcc metals by compression.' THEORY A simple quantitative argument will be presented to show that the development of these microstructures is a result of flow on the combination of slip systems for which the minimum amount of mechanical work is expended in producing a unit tensile (or compressive) strain. First it must be realized that the macroscopic strains of a crystal resulting from slip are given by: where d dy, and dc, are normal strain increments parallel to the x, y, and z reference axes; are crystallographic shear-strain increments on slip systems

Jan 1, 1964

JESSE L. JONES,* Pittsburgh, Pa. (written discussion?).-The most important criterion on which judgment of the quality of manganese bronze can be based is its freedom from lead. Not over 0.03 per cent. of lead should be present in a good grade of manganese bronze. While it is not questioned that manganese bronze with a high tensile strength and considerable ductility can be made .from materials that will give a lead content of possibly 2 to 3 per cent., there is no doubt that such material, while it may machine readily, will be found to withstand the impact test very poorly, and hence be unsuited for high-grade engineering work. When lead is present in considerable amounts, it forms in small pools in the alloy and the material has little strength at these points; in fact, such spots in the metal are equivalent to nicks in a test bar as far as their effect on tensile strength is concerned. A further objection to a high lead content is the ease with which it oxidizes and its consequent tendency to produce dross. A second characteristic of a high-grade manganese bronze is a low content of manganese. This should not exceed 0.05 per cent.; in fact, very many of the best grades of manganese bronze show, on analysis, only a trace of manganese or no manganese whatever. Manganese is a deoxidizer and its ready oxidation protects the other metals of the alloy; but if it is present in large amounts it will produce considerable manganese dioxide, which does not separate readily from the molten alloy and may produce black specks or drossy spots and render the obtaining of clean castings difficult. Aluminum should be present in a good grade of manganese bronze in only very small amounts. A content of 0.10 per cent. aluminum is ample. Larger amounts have a tendency to increase the shrinkage of the alloy, to give the ingots and castings a white, scruffy appearance, and to prevent the beautiful, golden, oxidization color characteristic of high-grade manganese bronze and a most excellent indication of quality. The work that the author of the paper has done is valuable from a con- servation standpoint, and it will supplement, in a marked degree, the advances that have been made by a number of manufacturers of manganese bronze in utilizing the turnings from this material. A number of firms have succeeded in making a very good grade of ingot metal from turnings and other light scrap, obtaining a tensile strength and elongation

Jan 4, 1919

By Richard H. Willey

EFFICIENT handling of large tonnages in open-pit mining demands, primarily, an abundance of well fragmented rock. To accomplish this, a drilling and blasting department composed of a well-knit, versatile group of workers and supervisors must be established. Some costs will remain relatively on the same level over a period of years, while others can be greatly lowered as will be shown. The Utah Copper Division, Kennecott Copper Corp., Bingham Canyon, Utah, has been ever alert for improvements in operating methods and equipment to gain increased efficiency and lower costs. BINGHAM CANYON MINE The greatest dimension of the mine is 8000 ft northeast-southwest with a width of 5000 ft southeast-northwest. From the lowest level, at an elevation of 6040 ft above sea-level, the mountain rises in 27 benches on the west side to W level (elevation 7800 ft) and 21 benches on the east side to Q level (elevation 7460 ft). At the inception of open-pit mining in 1906, the overcapping of leached porphyry had to be removed to reach a commercial grade of sulphide ore. The overcapping or waste now remaining is quartzite with intercalated limestone beds. The limestones are usually soft in nature except in the south-middle portion of the mine where they have been metamorphized along the contact zone. This area usually gives drilling and blasting operations a great deal of trouble. Here occurs the greatest amount of secondary blasting, as the well-established fracture planes cause the altered beds to break into large boulders. Several massive quartzite "ribs" occur in the overburden, and as a result, the uniform breakage is difficult to obtain. The major quartzite areas have been subjected to complex folding, fracturing and faulting because of the intrusion of the underlying stock. The monzonite porphyry, which carries the commercial values, presents no serious drilling problem because of its softness and extensive minute fracturing throughout the mass. A series of major slips or faults pass through the ore body which, although of considerable advantage to the drilling and blasting department, sometimes works to the disadvantage of the track department. Drilling and blasting of the porphyry apparently becomes easier as depth is attained, but highly siliceous streaks throughout the pit still present difficulties. At no place is the rock of such character as to allow excavation without preparations. On certain higher elevations or levels, old fill material can be dug by the shovels, but only at some risk to equipment because of bank slippage. PAST METHODS At the outset of shovel operations in 1906, drilling was done with the Ingersoll-Rand F-24 piston drill mounted on an un-

Jan 1, 1947

By M. Muskat

Calculations are reported on the differential sensitivity of the updip invasion of oil strata of varving permeability to the driving pressure differential. It is assumed that the water-oil interfaces advance with sharp fronts, or that the microscopic displacement efficiency is independent of rate and capillary pressure effects. It is found that, under such conditions, limitations of withdrawal rates will not greatly inhibit the "fingering" and bypassing tendency through high permeability strata unless the differential fluid head across the original oil column is of the order of or exceeds about 80 per cent of the driving pressure differential. In practice, such restrictions will be feasible only for oil reservoirs and aquifers of high permeability and dip, but may develop automatically under combined gas injection and water drive operations. INTRODUCTION A commonly expressed view regarding the intrusion of edge-waters into oil producing formations is that the geometry of such advance is rate sensitive. Specifically, it has been suggested that high rates of advance, stimulated by rapid withdrawals, will lead to "fingering" and an irregular type of invasion, whereas at low withdrawal rates the water encroachment will be more uniform. Two factors tend to support this view. One is the resultant effect of capillary pressure and gravity gradients in the displacement processes' involved in water intrusion, which are magnified at low rates of flow so as to improve the recovery efficiency. The other is the direct retarding effect of the rising water head as it advances upslope into the producing area. Capillary pressure forces give rise to a rate sensitivity of the oil recovery by water displacement in uniform strata as well as differential effects in non-uniform formations. These are basically independent of the effect of gravity and would also occur in horizontal beds or when the oil and water have the same density. Unfortunately, however, the fundamental equation describing the displacement process under the action of capillary pressures can be solved only by numerical or graphical procedures, and moreover the solutions are sensitive to the character of the capillary pressure and relative permeability curves.* On the other hand, the direct effect of gravity can be given a formal analytical solution if the simplifying assumption is introduced that the water advances with sharp fronts in the individual uniform strata. It depends on the absolute permeabilities of the water invaded zones and hence results in a rate sensitivity of the differential invasion in stratified media. Although a tieatment of this factor alone will not give a complete evaluation of the effect of rate on water intrusion in non-uniform pays, it should provide at least a semiquantitative measure of the sensitivity of "fingering" to withdrawal rate. Such a treatment will be presented in the following sections. GENERAL THEORY The basic element of the theory is the history of water advance updip in a uniform stratum (Fig. 1). In contrast to the assumption of constant flow rate, generally made in the analysis of displacement processes, we shall assume here that

Jan 1, 1951

By John P. Bryant, Samuel Kincheloe

Plant nutrients are obtained by plants from both the air and the soil. Carbon dioxide, a gaseous form of carbon and oxygen, supplies the carbon which usually makes up 50% or more of plant structure. Plants are capable of absorbing carbon dioxide directly from the air. Most of this nutrient comes from the air, although some carbon dioxide is absorbed by soil water and taken into the plant as liquid. Growing plants use more water than any other substance. Plant nutrients in the soil dissolve in soil water; soil water entering the plant carries nutrients into the plant structure. Water is then given off into the air as the plant breathes or transpires. Inorganic or mineral nutrients essential to plants are supplied through the soil. Inorganic or mineral composition of plants usually is less than 5% of their weight. In most crop-growing areas, much of this nutrition is inadequately supplied from the soil and must be provided by fertilizers. Proper fertilization of a soil to improve its mineral level and productivity is the role of the fertilizer industry. The 13 essential plant nutrients which often must be added to soils or plants and are generally considered fertilizer minerals are categorized as primary minerals (nitrogen, phosphorus, and potassium); secondary minerals (calcium, magnesium, and sulfur); and micronutrients, or trace minerals (boron, iron, manganese, copper, zinc, molybdenum, and chlorine). These classifications are based on quantity of nutrients utilized by plants and have no implication as to function or degree of necessity. One point of major significance to the fertilizer industry is that not all nutrient carriers supply that nutrient in a chemical form which will be available to the plant. Thus, a product which may be considered a fertilizer mineral may require substantial processing or may require substantial processing or treatment before it becomes useful as a nutrient carrier. Fertilizer Industry Scope Until about 1900 demands for higher crop yields were met simply by bringing new agricultural lands into cultivation. Since that time great progress has been made in increasing yields through fertilization and improved varieties and cultural practices. The importance of the fertilizer industry to the economy and welfare of the US is widely recognized. Fig. 1 illustrates the relationship of lime and fertilizers to crop yields. In terms of tons of fertilizer products, the growth of the industry has been phenomenal, particularly between 1950 and 1980. Table 1 shows the increase in fertilizer usage. Primary Plant Nutrients in Fertilizers Primary minerals (nitrogen, phosphorus, and potassium) are designated as such because [ ]

Jan 1, 1983

By A. L. Simpson, J. M. Edwards

The application of the Scintillometer to radioactivrty surveys in boreholes of oil wells has made it possible to determine bed thickness with a high degree of accuracy. This fact, combined with known relation of logging variables, makes thin bed porosity determination practical. With the use of the Scintillometer a method hot been derived whereby the apparent level of radiactivity, as recorded on radiation logs, may be converted to the true level. The true level of radioactivity is that level to which the recording pen would have traveled had the detector remained at a given depth for on infinitely long period of time. This factor is: radioactivity level, Ra, is the apparent radioactivity level, T is the bed thickness, D is drag, and L is the length of the detecting system. This method depends entirely on accurate measurements of bed thickness and drag. A thorough discussion of the concept of time constant and logging speed as related to drag is undertaken. INTRODUCTION Neutron curve interpretation has become one of the accepted methods for porosity determination in oil field practices. A great deal of literature has been published about neutron derived porosities, but this has been concerned with thick beds, or possibly even averaging of a series of thin beds as a single unit. There has been a lack of written information on methods whereby porosity can be evaluated for beds less than 10 ft in thickness. In certain areas, production is derived from relatively thin formations. The importance of thin bed evaluation, the fact that the Scintillometer is an adequate tool for this application, and the general lack of published information concerning neutron porosity for thin beds are the fundamental reasons for presenting this method of porosity determination. This concept is not put forth with the idea of discounting existing methods, but is merely suggested as a modification of other accepted methods of porosity determination which makes no allowance for quantitative evaluation of thin beds. The effects on the neutron log of counting statistics, statistical variation in the porosity of earth materials, and hole size must be taken into account to obtain neutron derived porosities. Since these effects have been described in past literature, the authors have not made an attempt to go into the subject in detail. With the use of statistical and repeated sections on the log, it may be determined which responses on the log actually correspond with lithologic changes. EFFECT OF DRAG AND ITS RELATIONSHIP TO TIME CONSTANT AND LOGGING SPEED Before entering into a discussion of porosity determination of thin beds, there should be a thorough

Jan 1, 1956

By C. E. Siebenthal

produce attractive and consequently more salable products. It would seem, however, that if solder and babbitt were cast in closed molds, just as good practical results would be obtained by the user, without his being able to give preference to solders of unnecessarily higher grade on account of their appearance. It would be hopeless for any one. manufacturer of solder to undertake a change of this kind, but if all manufacturers of solder agreed upon it, they would be able, in my opinion, to get the users of solder to take, and to approve by their practical tests, metals containing less tin than they have been accustomed to. The same is true with regard to babbitt metals. An illustration of how, in the use of an alloy, appearance sometimes is deceptive, is to be found in the case of what may be called intermediate grades of babbitt. I am thoroughly convinced that high-tin or high-lead babbitts are better than those containing both lead and tin with relatively high percentages of each. A high-tin babbitt should not contain more than about 10 per cent. of lead, and a high-lead babbitt should not contain more than 10 per cent. of tin, unless the percentage of antimony can be correspondingly increased. The intermediate babbitts, such as those that contain from 30 to 70 per cent. of lead or tin, may give nice appearing castings that flow easily, but they have not the serviceability of the high-lead or high-tin babbitts. Their hardness diminishes very rapidly as the temperature rises, and they have a relatively low softening point due to the eutectic components present. The Cadmium Supply of the united States* C. E. Siebenthal, † Washington., D. C.—From being one of the most maligned of metals—a veritable bugaboo—cadmium has almost overnight become respectable, though its slender claim to respectability rests almost wholly on the possibility of its substitution for tin. Preliminary to any campaign for such substitution, particularly for enforced substitution, the possible supply of cadmium should be determined as closely as possible; for that reason the statistical inquiry of which this paper embodies the results was undertaken. Production Cadmium is marketed in two forms, as metallic cadmium, in sticks or bars, and as cadmium sulfide, the pigment. The metal has found its greatest field of use in this country as a component of an easily fusible alloy that is used in automatic fire extinguishers. The sulfide is used to some extent in paints but chiefly to give color and luster to glass and porcelain. The metal was first made in this country by the Grasselli Chemical

Jan 1, 1919

By T. Sterry Hunt

But little was known of the coals of Southeastern Ohio until the present survey of the State under Dr. Newberry began its work. The results of the geological investigations of Prof. E. B. Andrews in this region, and of the chemical investigations of Prof. T. G. Wormley, both of which appear in the reports of the survey for 1869 and 1874, and more recent special reports by the former, together with some data for which I am indebted to the kindness of Dr. Newberry, and my own limited observations, have served me for the preparation of the following notice of the coals lying on the western border of the great Appalachian coal-basin in the region drained by the Hocking River and its tributaries, and belonging to the Lower Coal-Measures. Some uncertainty exists as to the place in the suc- ' cession of the lower coals to be assigned to the seams known and mined in the Hocking Valley. It is the opinion of Prof. Andrews that the inequalities of the original surface were such that we cannot identify in that region the lowest coals known in Northwestern Pennsylvania and the contiguous parts of Ohio, but that we must rather count from above downwards. These conclusions Dr. Newberry is not prepared to accept, and further researches will be necessary before certainty can be attained in this matter. Meanwhile it seems, from a study of its relations to the Pomeroy or Pittsburgh seam, that what is known as the great vein of the Hocking Valley, occupies the horizon of the Upper Freeport coal, E of the Pennsylvania survey, or No. 6 in Dr. Newberry's enumeration, counting from the base. This seam, in the region in question. assumes certain characteristics which, taken in connection with its geographical position, give it a great importance among the coals of the State. The area to be noticed includes the whole or parts of several townships in Perry, Hocking, Vinton, and Athens Counties, lying near the margin of the basin over which the vein in question assumes the character of a dry-burning or splint coal, and has a thickness varying from six to ten and even twelve feet. Its precise limit southward cannot at present be clearly defined, but it has been found as far south as the line of the Marietta and Cincinnati Railroad, with a thickness of six feet, and is mined at various points along the valley of the Hocking River, near Nelsonville, where it attains six or seven feet. To the northward, along the tributaries of this river, Sunday and Monday

By J. J. Tietjen, D. Richman

Single-crystal Gap lms been epitaxially grow from the vapor phase at a rate oJ 3 p per nzin without encountering a7Zy low-ang-le grain boundaries or debwading- the electrical properties of the material. This growth rate exceeds any value previol~sly reported for the vapor phase growth of Gap. In pure material, mObilities ns high as 175 sq cm per U-sec at room tenzperature and 1450 sq cm per v-sec at 77°K have been obtained. These values are anLong the highest that have been attai)led for this material. For the first time, Gap possesses a number of important properties which make it well-suited for use in electro-optic modulators. First, the transverse electro-optic effect is operable in this material, which makes it possible to increase the path length of the modulated iron doping of Gap has been achieved; this results i?z resistivities of approximately 10" ohm-cm. The problelrls of residual strain and isolated shorting paths in these crystals have been partially solved. Electro-optic modulation of visible radiation has been demonstrated with this material. It is anticipated that further improvement with regard to the probleins of strain and shorting paths will result in a practical Gap electro-optic modulator. radiation without increasing the applied voltage. In addition, this permits the use of thin crystals so that relatively small voltages are needed to provide the requisite high electric fields. Second, GaP is a cubic crystal and therefore does not introduce critical optical-alignment problems associated with birefrin-gent crystals, such as ammonium dihydrogen phosphate (ADP), and potassium dihydrogen phosphate

Jan 1, 1968

By John. C. Reed

THIS paper presents briefly some of the principal results of 3 ½ months field work during the summer of 1938 in the Chichagof mining district, southeastern Alaska. The report is preliminary and presumably will be followed later by a more complete report to be published by the Geological Survey. The paper is concerned principally with the structural geology of a block of steeply dipping graywacke as revealed underground in the Hirst Chichagof and the Chichagoff mines, the two principal mines of the district. The two mines have produced about $16,000,000 worth of gold and silver. The attitude of the graywacke, which is locally cut by dikes and sills of aplite, is remarkably uniform and trends about N. 62° W. The average dip is about 67° SW. The graywacke is cut by large faults, the best known of which are the Hirst and the Chichagof, whose average trends are about N. 30° W. and average dips about 75° SW. The faults at some places split into the bedding of the graywacke and at others are deflected from their normal trends for considerable distances along the bedding. The relative movements along the faults was northwest and up at about 30° for the south-west or hanging-wall sides. The ore bodies are elongate quartz lenses in the faults. Most of the quartz is mineralized but locally large quartz masses are too low grade to be mined. The emplacement of the ore bodies appears to have been structurally controlled in large part by the intersections of the faults with the bedding surfaces. Places where the faults split or are deflected appear to have been particularly favorable places for ore deposition. There has been some post-quartz movements along the faults but it is thought that such movements have not been extensive enough to greatly modify the original positions and shapes of the ore bodies.

Jan 1, 1939

By M. J. Saarivirta, P. P. Taubenbla

This paper presents some high-temperature properties of copper-zirconium conductor alloy compared to copper-chromium alloy. Definite superiority of the copper -zirconium alloy over the copper-chromium alloy at high temperatures is shown. RECENT investigations have shown that cold-worked copper-zirconium alloy possesses good room-temperature strength, ductility, and conductivity and maintains most of its strength at temperatures up to 450°C (840°F). As a result, this alloy is now used for many applications, such as commutator segments, resistant welding wheels and tips, rectifier bases, electrical contacts, and so forth. Early investigations1-3 have shown that the maximum solid solubility of zirconium in copper is close to 0.15 pct and the alloy containing Cu-0.10-0.15 pct Zr exhibits the optimum mechanical and physical properties. Results2 have also shown that the alloy has better elevated temperature strength and ductility than copper-chromium and copper-silver alloys. The present investigation was undertaken to learn more about the elevated temperature properties of copper-zirconium alloy and to compare these properties with those of the copper-chromium alloy. WORK PROCEDURE The commercial copper-zirconium alloy, Amzirc was selected for this investigation. Because this alloy is composed of oxygen-free high-conductivity copper and 0.10-0.15 pct Zr, it was believed that possible disturbance from impurities would thus be negligible. Copper-chromium alloys used in this investigation contained 0.40 and 0.70 pct Cr and balance copper. The Cu-0.40 pct Cr alloy was a commercial brand, whereas the Cu-0.70 pct Cr alloy was made from OFHC copper and Cu-5 pct Cr master alloy. It was made in a graphite crucible under argon gas cover and cast. In the preparation of specimens, all three alloys were treated to give the optimum properties; thus the Cu-0.15 pct Zr alloy was solution annealed at different temperatures to determine the desirable solution annealing temperature. It was then cold worked and aged at 375" to 400°C (705" to 750" F). A solution annealing temperature of 1000°C (1830°F) was selected for the copper-chromium alloys because this temperature is widely used in commercial practice. The same alloy was aged at 450°C (840°F) after solution annealing and cold working. It was found that the maximum precipitation hardening of the copper-chromium alloy occurred at this temperature. When aged after solution annealing, the aging temperature was 500°C (930"F) for both alloys. The following properties were determined: 1) Tensile properties as a function of temperature. 2) Effect of solution annealing temperature on high-temperature tensile properties. 3) Stress to rupture strength at 350° and 400°C (660"to750°F). 4) Impact strength. 5) Electrical conductivity and resistivity as function of temperature. 6) Thermal expansion.

Jan 1, 1961