Search Documents

By N. O. Johnson

THE Hog Mountain mine is a pyritic-gold property in the north central part of Tallapoosa County, Alabama, at an elevation of 800 ft. in the southern Appalachian region. It is 13 miles by a good secondary road from Alexander City, a station on the Central of Georgia Railroad. Since its discovery in 1839, the mine has been worked intermittently. The records of past operations are few and are scattered over a long period of time; however, available information indicates a production of approximately 12,000 oz. of gold prior to the present company's activities, which started in 1933. Additional 7844 oz. has been produced under the direction of the present management. The ore from stopes has averaged 0.200 oz. gold per ton; the ore from development, 0.136 oz. gold per ton. Silver, copper, iron and sulphur are also present but to date are of minor importance. The grade of ore in comparatively narrow veins makes necessary extreme vigilance in the methods of mining. Geology Wall Rock.-Hog Mountain consists of a quartz-diorite intrusion approximately 5000 ft. long by 1200 ft. wide. Its resistance to weathering, as compared to the surrounding schists, has led to the formation of a conspicuous ridge rising 400 ft. above the adjacent country. All the mining operations are confined within the limits of this quartz-diorite formation. . Except where there is excessive shearing, either parallel or at flat angles to the quartz veins, all the walls of the stopes within the limits of the veins are strong enough to make timbering unnecessary. Where shearing exists, there may be a sloughing off of the walls, especially in the process of drawing the ore. When this occurs, stulls are placed in the stope, either while the stope is advancing, or while ore is being drawn from a completed stope. In general, very little timber is required. Veins.-The quartz veins have been deposited along fracture planes in the quartz diorite. There are 20 principal veins, all of which are roughly parallel and strike at right angles to the long axis of the formation.

Jan 1, 1937

By R. Kossowsky, W. C. Johnston

CONSIDERABLE experimental data has been published in recent years on a few directionally solidified aluminum base eutectic alloys. The mechanical properties of A1-Al3Ni eutectic have been studied by Lemkey, Hertzberg, and Ford1',2 and Salkind et a1.3 where the alloy has been demonstrated to behave as a whisker reinforced composite with superior properties over many aluminum alloys. It has also been shown4 that aluminum reinforced with Al3Ni whiskers R. KOSSOWSKY, Member AIME, is Senior Metallurgist, Westing-house Research Laboratories, Pittsburgh, Pa. W. C. JOHNSTON, formerly with Westinghouse Research Laboratories, is Head, Department of Physics, George Mason College, University of Virginia, Fairfax, Va. Manuscript submitted March 28. 1969. IMD__________________ possesses excellent microstructural stability to 508°C. The effect of lamellar structure in A1-CuA12 eutectic was compared3 to the rod-like structure in the A1-Al3Ni eutectic, and was found to be better in low cycle fatigue. This was rationalized3 by postulating that a lamellar reinforcement was more efficient at blocking lateral plastic flow than a rod-like rein-forcement. The purpose of this study is to explore eutectic strengthening in other aluminum base alloys. The Al-Pd system5 forms a eutectic with aluminum and the intermetallic compound A13Pd at 25 wt pct Pd, and has a melting point of 615°C. A13Pd has an orthorhom-bic structure and transforms to hexagonal Pd2A13 at 785°C. Growth characteristics, compression yield strength, creep rupture, and microstructural stability of directionally solidified and as-cast alloys are investigated. Eutectic ingots having a nominal composition of 25 wt pct Pd were prepared by first compacting 1/2 in. diam by a in. high pellets from 99.99+ pct A1 and 99.99 pct Pd powders. The pellets were then levitation cast into 1/4 in. diam by 2 in. long copper molds. Directionally solidified bars were prepared by grinding the cast ingots to 0.195 in. diam, inserting them into alumina

Jan 1, 1970

By E. H. Griswold, W. J. Wilkins

Pressure control of oil wells may be defined as the adjustment of pressures within a well to obtain the most efficient and economic utilization of the natural gas energy with a minimum of sand troubles or irregular water encroachment. The purpose of this paper is to present the methods used by the writers in applying pressure control and a discussion of the various effects occurring within the wells affected. The benefits to be derived from the conservation of natural gas energy have been so adequately discussed and demonstrated in prior papers by various engineers that the effects on ultimate production will not be discussed other than to mention a few representative cases. The detrimental effects of irregular edge-water encroachment and of sanding up arc of general knowledge to the industry. Effect on Ultimate Production One of the strongest objections voiced against pressure control is that of the danger or inadvisability of deferring oil production by cutting the rate of production. It has been our experience that such deferred product'ion is returned within a few weeks or months rather than years and that an increased cumulative oil production is obtained in the early life of the well by conserving the natural energy. In many cases the rate of production is increased rather than decreased by the adjustment of pressures to obtain the minimum gas factor. Fig. 1 shows the history of a Wilcox sand well in northern Oklahoma, which was pressure-controlled from completion. It is noted that during the early months while flowing naturally through the casing the gas factor was decreased rather than allowed to follow its natural tendency to increase. A string of 21/2-in. tubing was run to restrict the flow and resulted in a decreased gas factor with a more sustained rate of production. When first placed on gas-lift the gas factor again tended to increase, but after the proper pressure adjustments were made, remained approximately steady. It was necessary to defer 100 bbl. per day of oil production in order to maintain this low gas factor. In March serious

Jan 1, 1929

By David White

While a country is small and its coal fields are not many, it may be possible to classify its coals on some basis that avoids both overlap and inconsistency, and that may be satisfactory to the particular country, such as geographic distribution or geologic age, or regional uses. In the adjoining country, however, the coals may differ more or less; broad areas may have escaped the erasure of transition zones by erosion, and the stages of alteration of the coals may lead to a classification different from and even incompatible with that of the other country. Such classifications, developed primarily along national lines, are essentially opportunistic. Further, many even of the "use" terms that have been in more common employment with a degree of international application have lost their significance and value, due to changes in industrial methods and urban life. When the number of coal fields is large and the classification is designed to cover the coals of many countries, the groups or divisions into which the coals are integrated are found to verge one into another; and, though the main divisions may be so naturally composed and oriented that they are relatively distinct and readily separated as entities or units when taken by themselves, the sequence, through classes, groups, and subdivisions, is so complete that we find transition zones through which boundaries must be arbitrarily drawn with minute technical definition. This situation, which is conspicuously illustrated in the United States, is due to the progressive evolution of all coals, irrespective of geologic age, from peats to successively higher ranks, which, if the progressive alteration goes far enough, ends with graphite. This evolution is now firmly established and its complete acceptance is but a matter of time. A classification of all coals in all coal fields can not escape this fact and must take into account all the stages in the transformation of the fuel from rank to rank through division to division, and through group to group. The plan here outlined aims at a natural classification of coals based on their evolution from peats to graphite. As in other classifications, the differentiation of the various groups and divisions takes account of changes resulting from the progressive losses of moisture and .of oxygen of constitution; the relative conservation of carbon; the progressive increase in fixed carbon (inverse to the loss of volatile matter) in

Jan 1, 1930

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 C. Richard Honeycutt, Frederick C. Langenberg, Guenter Pestel

Otto Schaaber (Institut für Harterei-Technik, Bremen-Schönebeck, Germany)— Langenberg, Pestel, and Honeycutt gave an interesting example of the grain refining effect nonstationary magnetic fields may execute on a solidifying metal. Probably some additional comments, based on more than a decade of experience with this method of influencing crystallization, may be useful. They refer to an attempt to explain the mechanism of grain refinement by such fields, and to recent European developments which have not been mentioned in the paper. I. During studies of the temperature distribution in a metal body near the phase boundary solid/liquid, an anomaly was observed under certain special conditions: a) direction of heat transfer as horizontal as possible, b) steady state (equilibrium, i.e,, solidification resp. melting rate exactly zero). In the liquid phase, immediately adjacent to the phase boundary, the temperature was found to be constant over an appreciable distance in spite of a high value of heat transfer (40.000 to 70.000 keal/ m2h).3 Convection, which might explain this phenomenon, could not be observed. Therefore another explanation had to be sought. The assumption that a metallic melt, especially at temperatures near the point of solidification, contains some sort of atomic arrangement with a higher degree of order than the surrounding liquid, now is generally accepted. Considering the differences in energy between such an arrangement and its environs, a transport of heat even in absence of any temperature gradient is conceivable by continued formation and redissolution of regions with a higher degree of order, i.e., with lower energy level.3 At this stage, it was not necessary to postulate any special condition as to the form or size of these regions or the distance between arrangements to be newly formed and those to be redissolved. However, a simple consideration shows that an energy transfer from one region to another will only be possible without loss of energy, if the distance between will be equal to the lattice parameters, and if, secondly, crystallographic axis or planes will be parallel.4 By the way, this assumption might give a reasonable explanation of the well known orientation effect of the heat flow during solidification. Any measures to prevent columnar crystallization should act upon this ordering mechanism: a) the regions with a lower energy (higher order) should not be allowed to arrange themselves parallel to the direction of heat flow, and their growth should be disturbed; b) all conditions leading to an appreciable heat flow of uniform direction should be avoided or removed. Condition a) may be satisfied by a physical force preferably under 90 deg to the main axis of the columnar crystals (i.e., parallel to the solidification front) acting on the ordered regions; condition b) by equalizing any differences in

Jan 1, 1962

Jan 1, 1969

By A. T. Corey, J. H. Henderson, M. R. J. Wyllie, C. H. Rathjens

The results of three-phase relative permeability tests on nine water-wet consolidated Berea sandstone samples are presented as composite ternary diagranls showing isoperms of oil, water and gas. Capillary pressure control was exercised over the flow of gas and oil in the presence of water. The water saturations ranged from 17 to 71 per cent pore volume. A method of calculating both the oil and water permeabilities of a three-phase system from the easily measured gas relative permeability is presented. EXPERIMENTAL PROCEDURE AND RESULTS A renewed interest has been shown in three-phase relative permeability as a result of recent developments involving underground combustion processes, steam injection, and other multiphase displacement processes. The experiments and results described here involved simultaneous flow of oil and gas in consolidated Berea sand with brine present as the wetting phase. Gas and oil relative permeabilities were measured on nine cores with CaC12 brine present as the wetting phase in saturations ranging from 17 to 71 per cent. The average residual liquid saturation of the cores was approximately 20 per cent. In order to make certain that brine was the wetting phase, the test cores were saturated with brine before contact with hydrocarbons. As an added precaution to avoid having oil displace brine from the wetting position as a result of changing wettability, each core was only used twice, i.e., first with a fixed percentage of brine and then for a gas-oil permeability determination with no brine present. The results, therefore, are presented as composite ternary diagrams representing the flow tests on nine individual cores having very similar properties. All tests were made using a modification of the capillary pressure techniquc described elsewhere. The effective oil permeability was measured before gas was introduced using a very small pressure gradient (a few centimeters of oil). This determination was made without selectively wet barriers in contact with the core. The cores were then placed between capillary barriers and gas-oil relative permeability curves obtained. The capillary barriers had been made water repellent with a silicone treatment. In determining gas-oil-water relative permeability in this fashion, control was exercised over the capillary pressure existing between the gas and oil. No control was exercised over the pressure difference existing between the oil and water. Athough an equal pressure gradient was applied to the gas and the oil phases, this pressure gradient does not exist in the water phase. Since the pressure gradient across the core was always much less than the displacement pressure of the fully saturated core, the pressure gradient can have caused only a very slight distortion of the oil-water interfaces. This slight distortion of the oil-water interfaces had a negligible effect on the validity of the oil permeabilities measured. The oil permeability, measured in the presence of water but with no gas present, was in every case equal. within experimental error, to the gas permeability of the gas-oil system when the oil saturation was the same as that of the water. Gas and oil relative permeabilities were plotted as a function of total liquid saturation. It was found that the gas relative permeability curves obtained on cores with brine present were identical with those obtained on the same cores with no brine present. The denominator for calculating oil relative permeabilities was the permeability found by extrapolation to infinite mean pressure (A la Klinken-berg). Fig. 1 illustrates gas-oil relative permeability results obtained on a typical core. The solid permeability curves represent the experimental data. The dashed oil relative permeability curve was calculated using the relationship;

Jan 1, 1957

By C. P. Besse, G. W. Osborne

Drilling operations on the Gulf of Mexico continental shelf are following two general plans. The first plan placed all buildings. equipment, and materials on a large platform while the second copies Lake Maracaibo drilling methods by placing a minimum of equipment on the platform and using a floating drilling tender or drill barge anchored adjacent to the platform in an attempt to take maximum advantage of flotation in an effort to reduce costs. A complete power rig, mud pits, pipe racks, and small auxiliaries have been placed on the platform as shown in Figure 1, to assure proper handling of drilling operations under the most adverse weather. This has the economic advantages of eliminating the fabrication of a large structure, a material reduction of rigging up time on each structure. and elimination of delay time on equipment while quarters and equipment placed on the tender are being rigged up. These factors have certainly proved their economic value in drill barge operations in the Louisiana and Texas coastal area. Naturally the heart of such an operation is the anchorage. This anchorage, to permit taking advantage of maximum economies. must hold the ship in a relatively fixed position under the following weather conditions: (1) Winter northwesters (2) Southeasterly gales (3) Severe rain squalls In hurricane weather all operations must be suspended regardless of method of operation and the floating tender will, if possible, be moved to a protected location. However, in case of an emergency the floating tender should be prepared to swing with the wind and seas on a single anchor as there is considerable doubt that either ship or anchorage could withstand the severe strains imposed by fixed anchorage in hurricane weather. Northwesters are reported to have developed wind gust velocities as high as sixty miles per hour and steady winds of approximately forty-five miles per hour. Fortunately these winds do not travel a great distance over water before arriving at our location, and, while they can possibly develop seas approximately eight feet high, the waves are short, and if taken on the bow or stern of a ship 250 feet or more in length they should not present a difficult problem. On the other hand southeast gales having a long fetch and maximum steady wind velocities of approximately thirty miles per hour can possibly develop long swells approximately twelve feet in height. These should develop the most severe anchorage problem. To combat these waves any workable anchorage plan should permit maneuvering the ship in such a manner as to head the bow or the stern into the seas and still maintain contact with the structure. Rain squalls develop wind gust velocities as great as sixty miles per hour. However, they are local and the seas have not been a source of great trouble. To permit continuous operation the anchorage must be able to withstand these winds broadside to the ship as the wind direction often changes radically in a very sliort time. All of these weather conditions are dangerous to small craft, deck cargoes,

Jan 1, 1949

By C. P. Besse, G. W. Osborne

Drilling operations on the Gulf of Mexico continental shelf are following two general plans. The first plan placed all buildings. equipment, and materials on a large platform while the second copies Lake Maracaibo drilling methods by placing a minimum of equipment on the platform and using a floating drilling tender or drill barge anchored adjacent to the platform in an attempt to take maximum advantage of flotation in an effort to reduce costs. A complete power rig, mud pits, pipe racks, and small auxiliaries have been placed on the platform as shown in Figure 1, to assure proper handling of drilling operations under the most adverse weather. This has the economic advantages of eliminating the fabrication of a large structure, a material reduction of rigging up time on each structure. and elimination of delay time on equipment while quarters and equipment placed on the tender are being rigged up. These factors have certainly proved their economic value in drill barge operations in the Louisiana and Texas coastal area. Naturally the heart of such an operation is the anchorage. This anchorage, to permit taking advantage of maximum economies. must hold the ship in a relatively fixed position under the following weather conditions: (1) Winter northwesters (2) Southeasterly gales (3) Severe rain squalls In hurricane weather all operations must be suspended regardless of method of operation and the floating tender will, if possible, be moved to a protected location. However, in case of an emergency the floating tender should be prepared to swing with the wind and seas on a single anchor as there is considerable doubt that either ship or anchorage could withstand the severe strains imposed by fixed anchorage in hurricane weather. Northwesters are reported to have developed wind gust velocities as high as sixty miles per hour and steady winds of approximately forty-five miles per hour. Fortunately these winds do not travel a great distance over water before arriving at our location, and, while they can possibly develop seas approximately eight feet high, the waves are short, and if taken on the bow or stern of a ship 250 feet or more in length they should not present a difficult problem. On the other hand southeast gales having a long fetch and maximum steady wind velocities of approximately thirty miles per hour can possibly develop long swells approximately twelve feet in height. These should develop the most severe anchorage problem. To combat these waves any workable anchorage plan should permit maneuvering the ship in such a manner as to head the bow or the stern into the seas and still maintain contact with the structure. Rain squalls develop wind gust velocities as great as sixty miles per hour. However, they are local and the seas have not been a source of great trouble. To permit continuous operation the anchorage must be able to withstand these winds broadside to the ship as the wind direction often changes radically in a very sliort time. All of these weather conditions are dangerous to small craft, deck cargoes,

Jan 1, 1949

Jan 1, 1883

Jan 1, 1956

Jan 1, 1942

Jan 1, 1942

[ ]

Jan 1, 1907

Jan 1, 1922

Jan 1, 1935

Jan 1, 1890

Jan 1, 1881

By R. A. Graham, R. W. Rohde, J. R. Holland

In a shock wave compression study of a martensitic Fe-30 pct Ni alloy, Graham, Anderson, and Holland' found a region of unusual compressibility extending from a few kilobars up to about 20 kbars. This region was characterized by a continuously decreasing shock wave velocity with increasing stress. In this note, we report the results of a study initiated to determine the source of this unusual compressibility. In earlier shock-loading experiments on martensitic Fe-30 pct Ni, Loree et a1.' determined that a phase change occurred at about 80 kbars. Subsequently, Bowden and elly found that samples of a similar material shock-loaded at about 100 kbars experienced a martensite-to-austenite transition. Their crystal-lographic analysis showed the transition was a direct reversal of the established martensite system to the austenite phase. The shock loading in the present experiments was accomplished by precisely controlled plane impact between two discs of the sample material. This configuration created a state of uniaxial strain in the two the front of a projectile which was accelerated to various velocities. Planarity between the impacting discs was controlled to 5 x 10-4 rad, and impact velocities were measured to 0.5 pct. From a knowledge of the Hugoniot relationships of the material and the impact velocity, the shock-wave stress can be calculated. Samples were shocked at 18, 50, 70, and 100 kbars. The specimen discs shocked at 18 and 50 kbars were instrumented with quartz gages to observe the stress time profile. A more detailed description of the experiment has been given previously.4 The shock-loaded specimens were recovered intact by decelerating them in a catcher filled with soft wood. Discs of Fe-30 pct Ni nominally 12.7 mm thick and 64 mm in diam were cut from bar stock. Chemical analysis of the material provided the following composition in weight percents: 29.5 Ni, 0.50 Mn, 0.21 Si, and 0.10 C, with traces of Cr, Cu, Mo, Al, and Co. The discs were austenitized at 650° C for 2 hr at a pressure of less than l0-' torr, and furnace-cooled. Martensite was then produced by quenching the discs at -196" and holding 168 hr. The initial martensitic structure formed is shown in Fig. l(a). Typical microstructures of samples shock-loaded at 18 and 100 kbars are shown in Figs. l(b) and l(c). The banded structure with the austenite regions running parallel to the shock propagation direction was characteristic of samples shock-loaded at all stresses. No such banding was found in samples that were not shock-loaded. Comparison of Figs. l(b) and l(c) shows that, although under the optical microscope the two microstructures are quite similar, the martensite plates of the specimen shocked at 100 kbars etched in a distinctly different manner. This unique etching behavior of martensite in samples shock-loaded above the 80 kbar transition point has also been observed by Leslie el al.' These investigators determined from X-ray and electron microscope studies that fcc martensite, similar in appearance to normal bcc martensite, had been formed under shock loading. A quantitative determination of the amount of austenite present after shock loading was made by X-ray techniques. Both the methods of Lindren' and Miller' were utilized. The results are shown in Table I. The error limits are those experimentally observed from two independent analyses of each sample and represent the precision of the experiment. The absolute error, which should be similar for each sample, is believed to be about 10 pct. It is seen that as the shock stress increases the amount of austenite present also increases. On the basis of the X-ray and microscopic observations, we conclude that shock loading below the 80 kbar ersal will initiate a martensitic reversal: the amount of reversal that occurs increases with in-

Jan 1, 1969