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By W. C. Krumbein

Geological problems are approached from a geometrical (space relations) viewpoint, a kinematical (time sequence) viewpoint, or a dynamical viewpoint. The first two require sound training in conventional geology and in field methods. The third approach requires a solid foundation of chemistry, physics, and mathematics. Modern training for geologists should include close integrltion of basic sciences with geological principles. Introduction Our knowledge of the earth has increased tremendously during the last half century. We know more about its surface configuration, the distribution of its natural resources, the proccssion of living forms that inhabited it in the past, the chemical composition of its oceans, the areal distribution of its surface rocks, the movements of its atmosphere, and so on. Not only do we know more facts about the earth, but we have a better understanding of the processes that take place on and within it, such as the nature of earthquakes, the thermodynamics of the atmosphere, the chemical equilibria involved in the formation of igneous rocks, the mechanics of stream flow, the dynamics of the earth's origin, and so on. Many sciences contributed to the sum total of this knowledge, including such established disciplines as geology, geography, physics, chemistry, astronomy, biology. Out of this accumulation of new knowledge grew also a group of new sciences, such as seismology, oceanography, meteorology, volcanology, hydrology. Collectively these latter are known as the geophysical and geochemical sciences, and to a large extent they began as branches of geology. Until the turn of the century, for example, the study of earthquakes (seismology) was a part of geology, although as early as 1846 Mallet, a physicist, had suggested that the subject could be investigated by elastic-wave theory. Comparatively little progress was made along these lines until the seismograph was developed near the turn of the century; since then, additional earthquake data have accurnul~ted rapidly, but more important, the interpretation of these data essentially has kept pace with their accumulation. In similar fashion, meteorology was generally considered a branch of geology as recently as one or two decades ago. Considerable progress had been made in such aspects as weather forecasting, but the science dates its recent rapid rise from the year 1911, when Bjerknes first applied the principles of dynamics to the analysis of air masses. The rapid development of such disciplines as oceanography, volcanology and hydrology was due in part to the application of principles of chemical equilibrium, of dynamics, and of thermodynamics to earth problems, by men who were essentially physicists or chemists by training. The last half century, therefore, and particularly the last two decades, saw the influx of numerous chemists and physicists into the realm of the earth sciences. In the meantime the main body of geology itself showed a marked growth, and

Jan 1, 1946

By John K. Hammes

INTRODUCTION This introductory paper presents a description and definition of what the finance function is and what it specifically means for the mining industry. In its simplest terms, finance is, "management of money matters". As an area within the discipline of business administration it draws heavily on the related fields of economics and accounting, and to a lesser extent on marketing and production. MINING FINANCE DEFINED In preparing to write about what finance means to the mining industry, I asked a number of mining people the question, "What does mining finance mean to you?" Most responded that mining finance was "How a company borrowed money for mine development", and perhaps half those questioned included "raising equity" in the definition. It is not surprising that the mining industry concept of finance is the providing of funds needed for the objectives of the business, for that was once a view shared by authorities in the field of business administration. Further, it is certainly the area where much of the emphasis has been placed in the past ten to fifteen years as the industry struggled with the development of more remote and more refractory or lower-grade orebodies while profitability and internal cash flow were below expectations. No wonder project finance became such a popular topic. Twenty years ago it is probable that the emphasis would have been on mine valuation, for that subject was the area of finance then most often examined in industry publications. Papers concerning the pros and cons of payback, internal rate of return, and discounted cash flow appeared regularly. Let's examine the following situations, each the result of a financial decision: - Funding the exploration program in a developing country was accomplished by buying the next six-months budget needs in local currency. One week later the currency devalued 30 percent. If the purchase had been delayed or the local currency borrowed short term, a substantial saving would have been made in funding the program. - A major mining company borrows heavily to finance both expansion of its primary mining business and its entry into several new industry segments. When markets for all of the commodities it produces turn down for a prolonged period, there is concern over the adequacy of cashflow to cover debt service in addition to other company needs. The company's financial officers, however, had arranged very large committed credit facilities from numerous financial institutions which assured the availability of funds for several years. This enabled the company to implement a strategy to conserve cash, sell assets and survive until conditions improved. Further, short term suppliers of credit also were comfortable with the assurance that longer term credit was there to support them. -A medium size mining company financed several mines independently with limited obligations on the part of the parent company. The company decided to refinance the operations under one agreement. More flexible terms, lower interest cost and a longer tenor financing were achieved in return for assuming the risk as a direct obligor. - The exploration and development group of a large mining company proposes to develop a new mine in a country in which the company does not presently operate. When the investment is rejected they are advised that one reason was that the reinvestment assumption inherent in the discounted

Jan 1, 1985

On June 1, the offices of the Engineering Division of the National Research Council were moved from Washington to the sixteenth floor of the Engineering Societies Building, 29 W. 39th St., New York City.

Jan 7, 1919

By R. Adair, W. R. Hudspeth, W. T. McDaniel

A NEW method for concentrating the flake mica either from present washing plant tailings or from new feed has been developed. In this paper, flake mica refers to that which occurs in weathered granites, alaskites, pegmatites, and schists in a form too fine to be considered sheet mica. It ranges in size from 1 in. or more down to 200-mesh or finer and occurs with kaolin, quartz, and partially kaolinized feldspar. Scrap mica, a term often used indiscriminately to describe everything other than sheet mica, will be used to denote the waste product from sheet mica mines and fabricating plants. Both flake and scrap mica are used in the mica grinding plants to produce wet-ground or dry-ground mica, although some flake mica recovered from clay mining operations is fine enough to be marketed without grinding.

Jan 3, 1951

By R. Schuhmann, J. Th. Overbeek, P. L. De Bruyn

THE technique of concentrating valuable minerals from lean ores by flotation depends upon the creation of a finite contact angle at the three-phase contact, mineral-water-air. If the mineral is completely wetted by the water phase, contact angle zero, there is no tendency for air bubbles to attach themselves to the mineral. However, when the contact angle is finite, the surface free energy of the system, water-air bubble-mineral particle, can be diminished by contact between the bubble and the particle, and if not too heavy the mineral will be levitated in the froth. With a few exceptions, all clean minerals are completely wetted by pure water. Thus the art of flotation consists in adding substances to the water to make a finite contact angle with the mineral to be floated, but to leave the other minerals with a zero contact angle. The contact angle concept and experimental measurements of contact angles have played important roles in flotation research for several decades.'-" Nevertheless, there remain unanswered some basic questions as to the scientific significance of the contact angle and the nature of the processes by which flotation reagents affect contact angles. The contact angle is a complex quantity because the properties of three different phases, or rather of three different interfaces, control its magnitude. Considering the interfaces close to the region of ternary contact to be plane, the relation among the contact angle and the three binary interfacial tensions is easily derived. The condition for equilibrium among the three surface tensions, Fig. 1, or the requirement of minimum total surface free energy leads to Young's equation, Eq. I: ysa — ysl = yLA cos 0 [1] According to this equation, the contact angle has one well-defined value. Actually it is found in many experiments that the value of the contact angle depends on whether the air is replacing liquid over the solid (receding angle) or the liquid is replacing air (advancing angle). The receding angle is always the smaller of the two.4 Two explanations have been offered for this experimental fact. According to some investigators,5-8 roughness of the surface causes apparent contact angles that are different for the receding and the advancing cases although the actual local contact angle may be completely determined by Eq. 1. The other explanation involves the hypothesis that the solid-air interface after the liquid has just receded is different from the same interface when no liquid has previously covered it.1,4 Adsorption of constituents of the air or liquid might play a role here. In this discussion the difference between advancing and receding contact angle will be neglected and plane surfaces where Eq. 1 describes the situation will be considered. But there is still a fundamental obstacle to the application of Young's equation. The surface tension of the liquid (rla) can easily be determined, but the two surface tensions of the solid (rsa and ySL) cannot be measured directly. Eq. 1, however, is not without value. By contact angle measurements it is possible to establish how ysl — ysl varies with the addition of solutes to the liquid phase. Also, Eq. 1 affords a convenient starting point for calculating net forces and energy changes involved in the process of bubble-particle attachment.1,2 . If for the moment surface tension of the liquid (yLa) is considered a constant, an increase in ysa — ysL, will tend to decrease the contact angle. A decrease in ySA — ysl, corresponds to an increase of the contact angle. In cases where ySA — ySL > yLa the contact angle is zero; it will only reach finite values when ysa — ysa has been decreased below YLA. Thus on the basis of Young's equation and contact angle measurements alone, it can be learned how flotation reagents affect the difference Ysa — ysl, but no conclusions can be drawn as to the effects of reagents on the individual surface tensions ysa, and ysL, not even as to signs or directions of the surface tension changes resulting from reagent additions. A quantitative relationship between the surface tension or interfacial tension and the adsorption occurring at a surface or an interface is given by the Gibbs equation, which for constant temperature and pressure reads dy = — 2 T, du, [2] where dy is the infinitesimal change in surface tension accompanying a change in chemical potential

Jan 1, 1955

By F. H. Daniels

IN this, paper it is my intention to, call your attention to* a few of the many producers using blast, now, in common use in Sweden, and also those constructed by the Washburn & Moen Manufacturing Company at their Quinsigamond Works. During a prolonged stay in Sweden the writer had an opportunity

Jan 1, 1881

By F. H. Daniels

IN this paper it is my intention to call your attention to a few of the many producers using blast, now in common use in Sweden, and also those constructed by the Washburn & Moèn Manufacturing Company at their Quinsigamond Works. During a prolonged stay in Sweden the writer had an opportunity

Jan 1, 1881

By J. H. Hensley

The mine of the Miami Copper Co. is in the Miami district, Gila County, Ariz., approximately 7 miles west of Globe. In 1906, the General Development Co. secured the ground now owned by the Miami Copper Co., and about a year later discovered ore in a prospect shaft at a depth of 220 ft. The Miami Copper Co. was organized in 1907, the claims held by the General Development Co. were transferred to it, and an active development campaign was inaugurated. The railroad was extended from Globe to Miami in 1909, a concentrating plant was constructed, and the company began producing early in 1911. The unit size of mineral tract in the district is the standard lode claim 600 ft. in width by 1500 ft. in length. Ownerships of land are held in fee. The geology of the district has been described by F. L. Ransome.' The formations of local importance are: The pre-Cambrian Pinal schist, which consists mainly of metamorphosed sedimentary rocks and is commonly of a thinly laminated sericitic variety; the diabase, which is thought to have been intruded in late Paleozoic or early Mesozoic times; the Schultze granite and granite porphyry, considered early Tertiary; the dacite of late Tertiary time; and the Gila conglomerate of early Quaternary. General Items Influencing Mining Methods The bodies of disseminated ore in the district are flat lying masses of irregular outline and variable thickness. As a rule, these masses lack definite boundaries; the orebody follows a curve along one of the main ridges, approximately 5500 ft. in length with a maximum width of 1600 ft. The minerals occur as finely divided and uniformly disseminated chal-cocite in the Pinal schist and Schultze granite. The typical overburden or capping is a barren rusty brown, very friable, highly siliceous, leached schist, or granite-porphyry. The topography of the district is fairly rugged and irregular; the altitude ranges from 3400 ft. above sea level, at the town of Miami, to 3900 ft. on the hills above the Miami orebody. The climate is mild; the mean annual temperature is 63.°F.

Jan 1, 1925

By C. H. Hewitt, J. T. Morgan

The Fry cocurrent in situ combustion project was carried out in a 3.3-acre portion of a lenticular body of Robinson sandstone of Lower Pennsylvanian age. This particular sand body is about 12,000 ft long and 3,500 ft wide; it varies in thickness from 0 to 55 ft, trends northeast-southwest, and occurs at depths between 880 and 936 ft. The reservoir is made lip of three distinct types of sandstone, each having characteristic reservoir properties. (See Table I.) Textural gradients, sedimentary structures, erosional basal contact, absence of marine fossils, and geometry of the sand body all indicate that the sandstone is of fluvial origin and part of an extensive complex of river-deposited sedirnents. Geographically oriented cores reveal that the direction of depositing currents was to the southwest, parallel with the sand-body trend. Directions of maximum pernleability also parallel the northeast-southwest trend. The layered nature of the sandstone reservoir and its directional properties have controlled the areal distribution of produced gas, the ignition behavior, and the vertical profile and horizontal extent of the conbustion zone. INTRODUCTION This paper is the first of a series of three papers that describe Marathon Oil Co.'s Fry in situ combustion test. This first paper contains the results of a detailed study of the geology and reservoir characteristics of the Robinson sandstone reservoir in which the Fry test was conducted. The second and third parts of this series report on the field operations' and performance. The geologic work reiated to cores cut through the combustion zone, and to the effect of reservoir properties on the combustion process is included in the third paper.' GEOLOGIC STUDY OF THE FRY RESERVOIR The close spacing of continuous cores in the Fry combustion site provided an unusual opportunity to study the details of distribution of lithology and reservoir properties within a petroleum reservoir. The objectives of the study were: 1. To determine the distribution of rock types within the Robinson sandstone in the Fry area; 2. To determine the relationship of porosity and permeability to rock properties and establish the distribution and homogeneity of reservoir properties; 3. To determine the origin of the Robinson reservoirs so that attempts could be made to predict the size, shape, distribution, extent and continuity of Robinson reservoirs; and 4. To determine what effects, if any, the reservoir rocks might have on the combustion process, so that the process might be better evaluated. AVAILABLE MATERIALS Continuous cores were cut from 14 wells in the vicinity of the Fry site. Ten of the cores are from within the 3.3-acre pattern; six of the 10 were cut prior to combustion, and four were cut through the combustion zone. Cores from the Emma Fry No. 15, Wampler 0-2 and Fry B wells (Figs. 1, 2 and 9) were geographically oriented by the Eastman Oil Well Survey Co. Maps, electric

Jan 1, 1966

By F. J. Menzer, E. M. Schern

The Morenci/Metcalf porphyry copper mining operation, located in southeastern Arizona, currently processes approximately 91,000 tonnes of ore per day and has copper ore reserves estimated to be in excess of one bill ion tonnes. Functional groups within the Geology Department (currently staffed with six professional and two support personnel include mine geology, project geology, and hydrogeology. The primary task of mine geologists is daily preblast bench face mapping with grade and mill amenability estimates. Auxiliary duties include detailed in-pi t metal distribution evaluation, mineragraphic work and flux quarry geology. Project geologists conduct exploration and preliminary development projects both within and outside the Morenci district and provide support to ore reserve block modeling and geotechnical work performed by the Morenci mine engineering group. Hydrogeologists handle exploration for and development of groundwater resources and groundwater flow modeling, mine dump leach solution penetration and recovery evaluation, and tailing dam water reclamation.

Jan 1, 1984

By W. Mostowitsch, H. O. Hofman

The mineral gypsum, CaSO4 + 2 H2O, has been used for many years as a sulphurizing and basic flux in several smelting-operations. Thus, in smelting oxide nickel-ore in the blastfurnace, it is commonly added to the charge to furnish the sulphur necessary for collecting the metal in a matte, and a base for slagging the siliceous gangue. In the concentration of lead-copper matte in the reverberatory furnace it has been used for years at Preiberg, Saxony,1 for a similar purpose, and for producing at the same time a copper-matte with less than 0.15 per cent. of Fe. The latest use gypsum has been put to is in the blast-roasting process of Carmichael-Bradford.2 The term " blast-roasting," given by A. S. Dwight3 to the Dwight-Lloyd method of roasting and agglomerating: is a happy generic term which covers the ground better than the " lime-roasting " of Ingalls5 or the " pot-roasting " of Austin: in that it leaves the operation independent of the character of the flux and the form of apparatus, and retains the characteristic feature of this class of processes—namely, that of using forced draft. In the Carmichael-Bradford process the dehydrated material, mixed with galena-concentrate, acts as a diluent and a flux. The process differs in this from the Huntington-Heberlein7 and the Savelsberg8 processes, in both of which limestone is used.

Jan 1, 1909

By A. N. Holden

A DISLOCATION mechanism has been described by Cottrell' by which metals can yield locally, I. form Liiders bands, giving rise to a characteristic stress-strain curve with a sharp yield point and appreciable strain at constant or decreasing stress. It is undoubtedly the best mechanism that has been suggested to date." In its present development, however, the dislocation mechanism provides a more satisfying explanation for the sharp yield point than for the extensive localized flow occurring at the lower yield stress. The primary objective in this paper is to extend the dislocation mechanism to account for localized cataclysmic flow by a dislocation collision process and to give experimental evidence to support such a process. Only the yielding of iron containing carbon -will be discussed, although other metal-solute systems are known to behave similarly. Cottrell Mechanism In brief, Cottrell explains the yield point in the following way: The dislocations in iron which must propagate to produce slip usually lie at the center of local concentrations of carbon atoms, since segregation about these dislocatlons relieves some of the local stress resulting from them. A dislocation surrounded by a "cloud" of carbon atoms is thus anchored, and a higher stress is required to set it in motion than to move a free dislocation. Considering all available dislocatlons to be anchored in this fashion, the iron exhibits a yield point when the first dialocations break free and move through the lattice causing slip. This first breaking away of a dislocation enables other dislocations to break loose by "interaction" and the process becomes a cataclysm producing local deformation or Luders bands. The yield point in the stress-strain diagram for iron is absent in freshly deformed material, but returns gradually with time; the phenomenon is one aspect of what is called strain aging. The rate at which the yield point returns following straining depends on the temperature of aging. According to Cottrell the rate of return of the yield point in strained iron is limited by the rate of diffusion of carbon at the aging temperature, the mechanism is onr: of reforming the solute atmospheres around carbon-free dislocations that had stopped moving coincident with the removal of stress. If the specimen is retested immediately after straining and unloading, carbon will not have had time to diffuse to, and re-anchor, dislocations and the yield point will not occur. The carbon diffusion limitation for the rate of strain aging apparently applies if the criterion for strain aging is either the change in hardness" or the change in electrical resistance" of the strained speci- men with aging time. The possibility exists, however, that the yield point actually returns to strained iron at some rate other than that deduced from hardness or electrical resistance data. Therefore, as a preliminary experiment, the rate of yield point return in a rimmed sheet steel strained 6 pct in tension was measured at 27°, 77°, and 100°C. A plot of yield-point elongation for each of these temperatures against aging time appears in Fig. 1. The aging process is described by curves which rise to a plateau value of elongation that seems independent of temperature, but at a rate that depends on temperature. Very long times lead to a further rise in the yield-point elongation above the plateau value. However, if the later increase in yield-point elongation is ignored and the log of the time to reach half the plateau value of elongation is plotted against 1/T, a straight line results for which an activation energy of about 25 kcal pel- mol may be assigned. Within the accuracy of this sort of experiment this is approximately the activation energy for the diffusion of carbon in iron (20 kcal per mol), and the carbon diffusion limitation suggested for the yield-point return on strain aging is valid. The Cottrell mechanism thus explains in a qualitative manner the occurrence of a yield point in iron and its return with strain aging. It fails, however, to explain some of the other experimental observations that have been made of the yielding behavior of iron. For example, it is known that the yield point in iron becomes less pronounced with increasing grain size. Annealed single crystals of iron have very small yield-point elongations .if indeed they have any,' compared to a polycrystalline steel. If the only requirement for a yield point is that the dislocations in the lattice of the annealed. material be anchored by carbon atoms, the difference in the behavior of single crystals and polycrystals is not explained. That a dislocation mechanism may be entirely consistent with little or no yield point in an annealed single crystal will become apparent later when dislocation interaction is discussed. Strain aging produces a definite yield point even in single crystals. This accentuation of the yield-point phenomenon in single crystals after strain

Jan 1, 1953

By Lester A. Blackner

The Ray Consolidated Copper Co.'s mining property is located on Mineral Creek, 6 miles north of Kelvin, at Ray, Pinal County, Ariz. (Fig. 1). The mining claims now owned by the company consist of 126 lode claims, comprising 2,144.9 acres, containing at the beginning of operations 82,904,368 tons of 2.19 per cent. copper ore. General Characteristics of the Orebody The main orebody is a disseminated deposit in schist and porphyry formed by secondary enrichment. Its existence was proved by churn drilling, and it is at present one of the largest proved copper deposits in the world. The orebody itself covers 205 acres with an average thickness of 121 ft., and occupies a definite belt which has a northwest direction. Its length is approximately 5,000 ft. The width varies, being about 2,000 ft. at the west end and 2,500 ft. at the east, narrowing down irregularly from both ends to a few feet in the center. The thickness of the body varies greatly along the line of lode, ranging from a few feet up to 470 ft. thick. The ore horizon is not constant, but varies, following in a broad sense the topography. The body in general dips slightly to the northeast, and is broken up by numerous small faults and fractures. The ore-bearing formations, consisting of mineralized schist and mineralized granite porphyry, stand fairly well and offer no difficulty in mining operations. The bulk of the ore is chalcocite disseminated in schist. In places cupriferous pyrite is closely associated with the chalcocite. The mineralized gr'anite-porphyry forhations are contiguous to the ore-bearing schist. • Overlying the orebody is an oxidized zone of leached iron-stained schist, averaging 252 ft. in thickness, termed "capping." The Line of

Jan 1, 1916

By R. W. Raymond

The relations of Eckley B. Coxe to the Institute, as one of its founders and early Presidents, and, throughout its history, an enthusiastic supporter and a valued contributor, would alone

Jan 1, 1896

By Cyril Smith

SEVERAL investigators, mainly concerned with the mechanical proper-ties of the alloys, have studied the so-called aluminum bronzes after various quenching and reheating treatments. Of these works, perhaps the most complete is that of Bouldoires,1 who studied changes of length, electrical conductivity, thermoelectric force, hardness and micro-structure oh tempering quenched alloys containing 5 to 20 per cent of aluminum, although the work of Carpenter and Edwards,2 Curry,3 Greenwood,4 Braesco,5 Matsuda;6,7 Grard8 and others has added much to our knowledge of the changes occurring during tempering. The so-called acicular ß decomposes on tempering at temperatures between 350° C. and the eutectoid, giving rise to a Widmanstätten structure of a needles in a matrix of d or fine a + d, associated with an increase in hardness and almost complete loss of ductility. Matsuda, studied the' eutectoid transformation by means of dilatation and electrical "conductivity measurements during cooling at different rates. He found that on cooling at the rate of 10° C. per minute there was a decrease in electrical resistance and in length instead of the usual increase which occurred with slow rates of cooling. On tempering the rapidly cooled samples, the increase commenced at about 400° C. and at 520° C. the resistance and length had reached the equilibrium values. These peculiarities he accounted for as being due to a transitional phase ß' being formed, ß having an electrical resistance and volume less than either ß or a + d.

Jan 1, 1933

By E. C. Wright

THE bessemer process is nearly one hundred years old. William Kelly, the American inventor, was able to demonstrate that he had accomplished the pneumatic purification of molten pig iron as early as 1847; Henry Bessemer's English patent was granted in 1855. The application of this steelmaking process since then and the present position of bessemer steel are concisely discussed on pages 355 and 356 of the fifth. edition of "The . Making, Shaping and Treating of Steel." The great expansion of the automotive, machine-tool, chemical and oil industries after 1910 opened up a large market for special steels, whereas the output of steel before that time was mainly for structural purposes. The need for building more blast-furnace capacity complementary to bessemer operations, combined with the availability of the necessary amounts of steel scrap, both contributed to the extension of open-hearth plants at the expense of bessemer capacity. The ability of the open-hearth furnaces to consume virtually all types of raw materials as far as phosphorus content is concerned, and the need for selecting low-phosphorus ores of rapidly decreasing sources for the bessemer, also played a part in the reduction of bessemer steelmaking operations and the increase in basic open-hearth plants. As a consequence, the proportion of bessemer steel made in this country decreased from 65.7 per cent of the total in 1900 to 37.1 per cent in 1910, and only 6.8 per cent of the total in 1937. The metallurgical concepts existent between 1910 and 1920 caused the writing of many specifications of very low phosphorus and sulphur content, which definitely barred bessemer steel from many commodities. Now sulphur is being added to many open-hearth and bessemer steels in amounts far exceeding the maximum sulphur content of good bessemer steel. Rephosphorizing is also widely practiced for several specific applications. Even today, the chemical-analysis limits of many important steel specifications have an arbitrary and archaic tinge. The old standard "0.30 .to 0.60 per cent manganese" might be mentioned in this connection as similar to the rigid requirements for maximum sulphur and phosphorus that were established at least 25 years ago. The literature is full of vague and complex discussions of the effects of nitrogen and oxygen where these elements existed in steel in amounts less than 0.02 per cent. Many failures have been attributed to these elements without reasonable proof on which to base the conclusion. Methods of determining oxygen in steel require such complicated equipment that only a few research laboratories have the required apparatus. Even so, the accuracy of oxygen determinations in steel has been only recently reproducible. Up to the present time, no one has succeeded in obtaining a sample of molten steel that accurately indicates the full. oxygen content of the metal in the furnace or ladle because the molten sample

Jan 1, 1944

A regular feature of the December issue is to be abstracts of graduate theses in the mineral industry field presented during that year. The following abstracts were submitted for this first article in the series.

Jan 1, 1975

By Wayne E. Glenn

The San Miguelito Field of Ventura County, California, lies along the coast approximately five miles northwest of the city of Ventura. The structure is one of several in the Ventura anticline, a series of anticlinal folds trending northwest-southeast through the San Miguelito Field. The Ventura Avenue Field lies to the southeast along the anticline, and Padre Canyon and Rin-con Fields lie to the northwest; the series then extends beneath the Pacific Ocean. Production is obtained from the Lower Pico and Repetto formations of Pliocene age, and oil accumulation is controlled by faulting, lithology and structure. The first well in the First Grubb Pool was completed in November, 1931, and to date 48 producing wells have been drilled on the 276 productive acres. Approximately 685 ft of net pay are contained in the eight sand bodies grossing 1,220 ft of section. Production of oil to date has been 15,-600,000 bbl. A gas injection project was instigated in April, 1940, but was discontinued in September, 1949. This paper is confined to a discussion of the development and performance history of the First Grubb Pool of the San Miguelito Field. LOCATION AND GEOLOGY The San Miguelito Oil Field is located in Ventura County about five miles northwest of the city of Ventura along the coastal highway to Santa Barbara. It is located within sections 23, 24, 25, and 30 of Township 3 North, Range 24 West, San Bernardino Base and Meridian. Surface elevation in the field ranges from sea level to plus 1,200 ft, and the terrain is extremely rugged. The structure is well defined on the surface and on the wall of the Amphitheatre Canyon where appears a so-called "text book" anticlinal section. The San Miguelito structure is an asymmetrical, elongated anticline about two miles long and three-fourths of a mile wide. The trend of the axis of the anticline is northwest-southeast. Fig. 9 illustrates the contours and major faults of this structure. Dips on the southwesterly flank average about 40 degrees, whereas the northeasterly flank ranges from 60 to 75 degrees. There are several faults striking generally east and west. These faults do not appear to affect materially the area of accumulation or performance behavior. It is believed that accumulation was affected by steeply dipping beds and extremely low permeability of the northeast flank of the structure. As shown by the typical log, Fig. 1. the San Miguelito Field is divided into two stratigraphic producing intervals. The First Grubb Pool comprises the interval from the "G" to "L" markers; the Second Grubb Pool from the "L" to "M" markers. The First Grubb Pool, ranging in thickness from 1,105 to 1,680 ft, with an average of 1,220 ft, includes approximately 685 ft of oil-bearing sands. The First Grubb zone consists of eight sand intervals separated by shales. The shale bodies separating the eight sand intervals within the First Grubb Pool are continuous throughout the major part of the structure and serve as an effective barrier. Many of the thin, irregular shale or siltstone streaks within these sand bodies are discontinuous and do not affect well performance appreciably. The productive horizons in the First Grubb Pool are siltstones and sandstones of the Lower Pico and Repetto formations of Pliocene age. It is apparent from inspection of the typical log that the "G" to "L" interval might have been separated into at least six producing zones and selectively pro. duced. Unfortunately the electric log and some of our modern tools were not available or were in their infancy dur. ing the period 1931 through 1937. Not until 1937 when eight wells had been completed were there sufficient geological data to permit definition of the sand bodies. Then the problem of reservoir control in this multiple-sand field, where all sands are open to a common

Jan 1, 1950

By John E. Miller

The Miller Number System is a well established method of measuring the relative abrasivity-friability of slurries, resulting in data that can be used in the selection of pump type and in forecasting wear-life of pumps and pipelines in slurry service. 1,2 Then after the pump type is selected, a Flow Analysis is determined by computer using pump design and operating parameters. This is used to determine pulsation control, suction requirements and stabilization, etc.

Jan 1, 1977

By E. C. Wright

The bessemer process is nearly one hundred years old. William Kelly, the American inventor, was able to demonstrate that he had accomplished the pneumatic purification of molten pig iron as early as 1847; Henry Bessemer's English patent was granted in 1855. The application of this steelmaking process since then and the present position of bessemer steel are concisely discussed on pages 355 and 356 of the fifth edition of "The Making, Shaping and Treating of Steel." The great expansion of the automotive, machine-tool, chemical and oil industries after I9I0 opened up a large market for special steels, whereas the output of steel before that time was mainly for structural purposes. The need for building more blastfurnace capacity complementary to bessemer operations, combined with the availability of the' necessary amounts of steel scrap, both contributed to the extension of open-hearth plants at the -exense of besskmer capacity. The ability of the open-hearth furnaces to consume virtually all types of raw materials as far as phosphorus content is concerned, and the need for selecting low-phosphorus ores of rapidly decreasing sources for the bessemer, also played a part in the reduction of bessemer steelmaking operations and the increase in basic open-hearth plants. As a consequence, the proportion of bessemer steel made, in this country decreased from 65.7 per cent of the total in 1900 to 37.1 per cent in 1910, and only 6.8 per cent of the total in 1937. The metallurgical concepts existent between 1910 and 1920 caused the writing of many specifications of very low phosphorus and sulphur content, which definitely barred bessemer steel from many commodities. Now sulphur is being added to many open-hearth and bessemer steels in amounts far exceeding the maximum sulphur content of good bessemer steel. Re-phosphorizing is also widely practiced for several specific applications. Even today, the chemical-analysis limits of many important steel specifications have an arbitrary and archaic tinge. The old standard "0.30 to 0.60 per cent manganese" might be mentioned in this connection as similar to the rigid requirements for maximum sulphur and phosphorus that were established at least 25 years ago. The literature is full of vague and complee discussions of the effects of nitrogen and oxygen where these elements existed in steel in amounts less than 0.02 per cent. Many failures have been attributed to these elements without reasonable proof on which to base the conclusion. Methods of determining oxygen in steel require such complicated equipment that only a few research laboratories have the required apparatus. Even so, the accuracy of oxygen determinations in steel has been only recently reproducible. Up to the present time, no one has succeeded in obtaining a sample of molten steel that accurately indicates the full oxygen content of the metal in the furnace or ladle because the molten sample

Jan 1, 1944