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By A. M. Adair

The effect of cathodically charging zone-refined iron with hydrogen and the resultant yield stress-grain size relationship has been investigated by tensile testing at -31°C. The resulting Petch plots (using a least-squares analysis) reveal a significant reduction in the slope and an increase in the intercept for specimens cathodically charged with hydrogen, regardless of whether the hydrogen is present during testing or is removed by evacuation. Other than surface blistering, the major effect of cathodically charging this material is to create occasional grain boundary cracks and thus presumably a large number of free dislocations at grain boundaries. These results are consistent with the hypothesis that the slope of the Petch plot is related to the stress required to activate dislocation sources at or near pain boundaries. While there is no significant effect of the presence of hydrogen on the lower yield stress of this material, the ductility is considerably reduced. After hydrogen removal by evacuation, the ductility recovers substantially and almost complete recovery of ductility is experienced by the smaller grain size specimens. THE influence of hydrogen on the mechanical properties of ferritic materials has received much attention throughout the history of the metallurgy profession. This interest has stemmed from the obvious importance of preventing the catastrophic failure of parts in service, and from the desire to determine what mechanism is responsible for the observed behavior. The various mechanisms proposed for hydrogen em-brittlement have been discussed in detail by Tetel-man,'who concludes that a combination of the applied stress and hydrogen pressure within voids best accounts for the many experimental observations reported. From a quite reasonable correlation of the strain aging and delayed-failure behavior of a variety of materials,2-7 Troiano and coworkers are of the opinion that the delayed-failure mechanism (slow strain rate embrittlement as well) is better explained as a lattice effect; solute elements diffuse to regions of high triaxial stress, form uncondensed atmospheres there, and effect a reduction in the cohesive strength of the lattice. Since hydrogen yield points8,9 have been observed in ferritic materials, and since the hydrogen embrittlement process may be related to strain aging, one further contribution to embrittlement could be hydrogen-dislocation interactions which make crack blunting by plastic deformation a more difficult process. The etch" relationship offers a means of comparing the relative ease of initiating and propagating plastic deformation in metals and alloys. In the present study, this relationship was used to compare the behavior of zone-refined iron in three conditions: uncharged, cathodically charged with hydrogen, and cathodically charged with hydrogen and evacuated. These Petch plots and the observed ductility parameters allowed a separation of the effects of the very presence of hydrogen and the act of cathodically charging hydrogen into this material. MATERIALS AND EXPERIMENTAL PROCEDURE An ingot of zone-refined iron was obtained from Battelle Memorial Institute which contained the following (typical) interstitial impurities in ppm: carbon, 10 * 5; nitrogen, 1; oxygen, 22; hydrogen, 0.9. The ingot was cold-reduced to a 1/2-in.-sq cross section, recrystallized 1 hr at 575°C, and then straight-rolled to a thickness of about 0.105 in. Tensile specimens were milled from the strip having a 1-in. gage length

Jan 1, 1967

By E. P. Pfleider, O. Rellensmann

In the May 1959 issue of [=] the authors reported on the gyrotheodolite as used for determining azimuths in surface and underground work. Further research has led to the development of a new type of gyro instrument, the band-suspended gyro attachment, which is essentially an upset gyro attached to the top of a theodolite. The new gyro attachment is light enough to be mounted on any angle-measuring instrument if the design of the telescope standard permits. Gyrotheodolite units have been used to transfer meridian lines underground in the Coeur d'Alene mining district, although they have not been used extensively in the U.S. In other parts of the world, however, they have been adopted as the standard surveying instrument by mining engineers.

Jan 3, 1968

By Kyle Wightman

INTRODUCTION CRA Limited is the largest mining group in Australia by value of sales and the second largest company in Australia in terms of share market capitalisation. In the past 25 years, CRA, its predecessors and affiliates have been involved in a number of mining and further processing developments in Australia and elsewhere. Many of these have been financed using project financing techniques. These include Comalco's development of the Weipa bauxite deposits in Northern Queensland in the late 1950's, the Hamersley iron ore developments in the Pilbara region of Western Australia in the mid 1960's, the Queensland Alumina Limited alumina refinery in Gladstone, Queensland, at about the same time, and the Bougainville copper project in 1969/70. In the past three years CRA has again utilised project financing techniques to fund its Tarong steaming coal project in Queensland, the Blair Athol steaming coal project also in that State and CRA's interest in the Argyle diamond project in the Kimberley region of Western Austrlia. PROJECT FINANCE DEFINED Nevitt Definition Nevitt's is the most frequently quoted definition - "A financing of a particular economic unit in which a lender is satisfied to look initially to the cash flows and earnings of the economic unit as the source of funds from which a loan will be repaid and to the assets of the economic unit as collateral for the loan." Risk and Balance Sheet Treatment It is important to focus in more detail on two aspects of project financing, risk and balance sheet treatment. The assessment of the various elements of risk in a project and the sharing of that risk between sponsors and lenders is the most critical feature. At one end of the spectrum is full absorption of risk by the sponsor(s). This can be described as "on risk" or "on credit" or "full recourse" to the sponsor(s) and is effectively a corporate financing. At the other end of the spectrum the lenders absorb the whole risk in a non-recourse financing which is "off risk" or "off credit" for the sponsor. The other aspect is the sponsor's balance sheet treatment. If the balance sheet of the economic unit undertaking the project and the financing need not be consolidated into the balance sheet of the sponsor (because ownership does not exceed 50%) then the financing may be described as off-¬balance sheet. If consolidation is required then the financing is described as on-balance sheet. Most project financings involve some recourse to the sponsor, i.e. they are limited recourse. Very few are non-recourse or off credit to the sponsor. Limited recourse financings may be on-balance sheet although many may also be off-balance sheet insofar as consolidation is concerned. However, sponsor support may very well be a contingent liability to the sponsor and require disclosure by way of note to the balance sheet should consolidation not be required. CORPORATE FINANCE CONTRASTED A financing which is on credit or full recourse to the sponsor, whether it is directly borrowed or guaranteed by that sponsor, is a corporate financing. Lenders will tend to base their credit assessment on a historical assessment of the sponsor's activities and its financial results rather than an assessment of the project or a detailed assessment of the future activities and prospects of the sponsor. PROJECT FINANCE - A BORROWER'S PERCEPTION Although CRA could choose to arrange all finance on a corporate basis (except perhaps for the very largest projects or acquisitions), project financing techniques provide a number of specific advantages which CRA has noted and which should be carefully considered by a project sponsor. Advantages

Jan 1, 1985

By Sydney H. Ball

A QUARTER of a century ago, a pessimistic Belgian financier in conversation with the founder of the Belgian Congo, that great ruler, Leopold II, emphasized the danger to the colony should the synthesis of rubber be discovered. The king replied, "I do not worry. The Congo has had its ivory period; it now has its rubber period. Tomorrow it will have that of its mineral wealth; eventually that of agricultural products." That "tomorrow" arrived some twenty years ago. Through her mines the Belgian Congo has survived the present depression, and her mines for the next decade will safeguard her. The Congo, in turn. is the surest foundation industrially and financially of Belgium itself. In few, if any, political units is mining as dominant as in the Belgian Congo. In 1930, 1931 and 1932 mineral products represented respectively 67.9 per cent. 70.5 per cent and 59.3 per cent, of the total exports. In 1933 for each white person in the colony, there was produced about $1,675 worth of gold, diamonds, copper, tin ore and minor mineral products and in 1930 the per capita production, notwithstanding the larger population, was almost $2,000.

Jan 1, 1934

W. E. WRATHER, Wichita Falls, Tex. (written discussion*).-The appearance of Mr. Brokaw?s with-the chemical composition of "paraffin dirt" will be welcomed by oil geologists who have worked in the Gulf Coast district. It is to be hoped that it will lead to a discussion of the subject which will throw some light on the relation this peculiar substance bears to the occurrence of oil deposits. The problem of locating oil pools in advance of drilling is at the best a very intangible matter in the district along the Gulf Coast, and it is therefore desirable to make the most of any clew which may be of the least assistance to this end. Geologists have been familiar with "paraffin dirt" for a number of years, and have informally discussed its value as a surface indication of oil. But doubtless owing largely to the fact that they have been unable to define its exact composition, very little information has appeared in print on the subject. The presence of this baffling and somewhat indeterminate substance is now quite generally accepted as one of the most reliable indications of a gas seepage. The question is whether paraffin dirt necessarily indicates that the escaping gas is an emanation from an oil deposit, or whether it merely indicates that marsh gas (urethane) has here escaped from its source in "the abundant decomposing vegetation entombed in the sediments of the old Mississippi Embayment, and the Gulf Coastal Plain. The presence of this material has been relied upon to a great extent, both by oil producers and geologists, in the location of wildcat wells, since the discovery that it was associated with gas seepages. It is quite true that other surface indications were often present at such localities, but if, in addition, paraffin dirt could be found in the vicinity, this fact was accepted as the final justification for drilling a test well, despite the fact that no one seemed to understand its chemical composition or to know why it should be associated with oil. In fact, for a long time it has generally been accepted that the name is a misnomer, that very little, if any, paraffin is present in it, or, for that matter, any other known fraction of crude oil.

Jan 7, 1918

By Robert H. Hafner, Irvin R. Kramer

In recent years considerable interest has been shown in surface-alloyed metals, particnlarly those of chromium (chromized steels), which have excellent corrosion resistance under a variety of severe conditions, and may undergo bending and flanging operations without spalling. An early method1 employed to produce a high-chromium case on steel was developed by Kelley in 1921. It consisted of heating a low-carbon steel in intimate contact with powdered chromium in the presence of hydrogen at temperatures sufficiently high to permit diffusion of chromium into the steel. The usefulness of this process was limited because the extremely high tem- peratures of 1200º to 1400ºC. (2200° to 2550°F.) caused excessive grain growth and warpage. Louenstein and Ulmer2 packed iron castings in ferrochromium and com- mon salt, and heated for approximately three hours at 930º to 1040°C. (1700º to 1900ºF.). A recent and more practical method of depositing chromium on steel surfaces has been developed in Germany by Daeves, Becker and Steinberg3-8 and in Russia by Izgaryshev and Sarkisov.9 This process consists of passing gaseous chromium chloride over the steel to be chromized at temperatures of 900º to 1000ºC., or packing them in a porous, ceramic material that previously had been saturated with chromium chloride. They reported obtaining a Chromized layer, 0.004 in. thick, on low-carbon steels. Later, Daeves4 established a relationship between the carbon content

Jan 1, 1943

By Robert H. Hafner, Irvin R. Kramer

IN recent years considerable interest has been shown in surface-alloyed metals, particularly those of chromium (chromized steels), which have excellent corrosion [ ] resistance under a variety of severe conditions, and may undergo bending and flanging operations without spalling. An early method1 employed to produce a high-chromium case on steel was developed by Kelley in 1921. It consisted of heating a low-carbon steel in intimate contact with powdered chromium in the presence of hydrogen at temperatures sufficiently high to permit diffusion of chromium into the steel. The usefulness of this process was limited because the extremely high temperatures of 1200° to 1400°C. (2200° to 2550°°F,) caused excessive grain growth and warpage, Louenstein and Ulmer2 packed iron castings in ferrochromium and com- [ ] mon salt, and heated for approximately three hours at 930° to 1040°C. (1700° to 1900°F,). A recent and more practical method of depositing chromium on steel surfaces has been developed in Germany by Daeves, Becker and Steinberg3-8 and in Russia by Izgaryshev and Sarkisov.9 This process consists of passing gaseous chromium chloride over the steel to be chromized at temperatures of 900° to 1000°C., or packing them in a porous, ceramic material that previously had been saturated with chromium chloride. They reported obtaining a chromized layer, 0.004 in, thick, on low-carbon steels. Later, Daeves4 established a relationship between the carbon content

Jan 1, 1942

By Robert H. Hafner, Irvin R. Kramer

In recent years considerable interest has been shown in surface-alloyed metals, particnlarly those of chromium (chromized steels), which have excellent corrosion resistance under a variety of severe conditions, and may undergo bending and flanging operations without spalling. An early method1 employed to produce a high-chromium case on steel was developed by Kelley in 1921. It consisted of heating a low-carbon steel in intimate contact with powdered chromium in the presence of hydrogen at temperatures sufficiently high to permit diffusion of chromium into the steel. The usefulness of this process was limited because the extremely high tem- peratures of 1200º to 1400ºC. (2200° to 2550°F.) caused excessive grain growth and warpage. Louenstein and Ulmer2 packed iron castings in ferrochromium and com- mon salt, and heated for approximately three hours at 930º to 1040°C. (1700º to 1900ºF.). A recent and more practical method of depositing chromium on steel surfaces has been developed in Germany by Daeves, Becker and Steinberg3-8 and in Russia by Izgaryshev and Sarkisov.9 This process consists of passing gaseous chromium chloride over the steel to be chromized at temperatures of 900º to 1000ºC., or packing them in a porous, ceramic material that previously had been saturated with chromium chloride. They reported obtaining a Chromized layer, 0.004 in. thick, on low-carbon steels. Later, Daeves4 established a relationship between the carbon content

Jan 1, 1943

By Robert H. Hafner, Irvin R. Kramer

IN recent years considerable interest has been shown in surface-alloyed metals, particularly those of chromium (chromized steels), which have excellent corrosion [ ] resistance under a variety of severe conditions, and may undergo bending and flanging operations without spalling. An early method' employed to produce a high-chromium case on steel was developed by Kelley in 1921. It consisted of heating a low-carbon steel in intimate contact with powdered chromium in the presence of hydrogen at temperatures sufficiently high to permit diffusion of chromium into the steel. The usefulness of this process was limited because the extremely high temperatures of 1200° to 1400°C. (2200° to 2550 F.) caused excessive grain growth and warpage. Louenstein and Ulmer2 packed iron castings in ferrochromium and com- [ ] mon salt, and heated for approximately three hours at 930° to 1040°C. (1700° to 1900°F.). A recent and more practical method of depositing chromium on steel surfaces has been developed in Germany by Daeves, Becker and Steinberg3-8 and in Russia by Izgaryshev and Sarkisov.9 This process consists of passing gaseous chromium chloride over the steel to be chromized at temperatures of 900° to 1000°C., or packing them in a porous, ceramic material that previously had been saturated with chromium chloride. They reported obtaining a chromized layer, 0.004 in. thick, on low-carbon steels. Later, Daeves4 established a relationship between the carbon content

Jan 1, 1942

By A. B. Cook, C. J. Walker, G. B. Spencer

Although water will displace oil from a petroleum reservoir to a greater extent than gas will, there are some reservoirs in which gas rather than water should be used for pressure maintenance. This is indicated by the high-percentage oil recovery in the case history reports on the Pickton field1 in East Texas and the Raleigh field2 in Mississippi. In gas cycling, total oil recovery includes vaporized products from the immobile oil in addition to oil produced by displacement. If a large part of the immobile oil is vaporized, total oil recovery may be higher than that obtainable from pressure maintenance by water injection. However, the amount of immobile oil vaporized may range from almost 0 to 100 percent, and no simple and reliable method has been presented in the literature for calculating oil vaporization. Development of such a method was the purpose of this study. Several papers concerning the calculation of oil vaporization have been published,3 6 and each is based on the concept dealing with K values — equilibrium constants for the various components in reservoir oils. (K for a component in a system of vapor and liquid in equilibrium is the mole fraction in the vapor phase divided by the mole fraction in the liquid phase.) This appears to be the most logical approach. Yet, the problem is too great for a perfect solution, even with modem laboratories to analyze oils and high-speed digital computers to perform calculations; the number of components in reservoir oils is too large. Because of their complexity no two reservoir oils are exactly alike. Also, K values change not only with variations in pressure and temperature but also with composition of the reservoir oil. In addition, during gas cycling, the lighter hydrocarbons tend to vaporize first. Thus, the reservoir oil becomes more dense and less volatile as gas cycling continues. Furthermore, the greatest amount of oil vaporization occurs near the injection well. Therefore, a simplified method is required for calculating oil vaporization because a rigorous method is not practical. The present methods of calculating vaporization generally require knowledge of the reservoir oil composition in which the mole fractions of the lighter components through hexanes are given; the remaining oil is described as C, + (heptanes and others of greater molecular weights). Assigning one K value for the C,+ system provides the simplest solution, but this incorrectly assumes that K for C, + does not change as gas cycling continues. This assumption can cause large errors because the K value may become less than a thousandth of the original after a large amount of oil vaporization. Another way to solve the problem is to determine changing K values for C, + according to how much of the C, + has been vaporized. To determine these values a sample of the reservoir oil is injected into a pressure-volume cell, and dry gas is batched in and out of the cell. Appropriate measurements and tests are made to determine K

Jan 1, 1970

By D. L. Katz, M. J. Rzasa

The derivations of three methods of computing the static pressure gradients in natural gas wells have been presented to show the assumptions made. Charts were developed from which the pressure gradients may be read when the well-head pressure, the well fluid gravity, depth, and the average well temperature are given. A chart for estimating the well fluid gravity from the condensate content and separator gas gravity is included. The effect of the increased average well temperature after flow on the calculation of the static pressure gradient is discussed. Introduction Reservoir pressures have been calculated from well-head pressures for gas wells for many years. As the pressure measurements become more accurate, the need for a reliable calculation of the static pressure gradient often arises. This paper will develop the several methods for computing the pressure gradient in gas wells and make a comparison between them. The method of calculating static pressure gradients in common use is Eq. I (ref. I) or its counterpart which includes a factor for the deviation of the gas from the ideal gas law. P2 - P1 = P1(e0.0000347GX _ I) Eq. [I] in which P1 = pressure at well head, lb. per sq. in. abs. PP = pressure at bottom of well, Ib. per sq. in. abs. G = gas gravity X = depth of well, ft. An alternate method is to compute the average density of the gas in the well and multiply by the well depth in a manner similar to that used for liquid gradients. Derivation of Formulas A static pressure gradient is a special case of the general fluid-flow equation. Consider a pound of fluid flowing in a vertical column from point I to point 2, Fig. I. By an energy balance for fluid flowing from I to 2: U1 + P1V1 + u12/2g + X1 + q = U2 + P2V2+ u22/2g+X2 +W [2] in which U = internal energy, ft-lb. per lb. P = pressure, lb. per sq. ft. V = volume, cu. ft. per lb. u = average linear velocity, ft. per sec. X = height above datum, fl. q = heat absorbed by fluid, ft-Ib. pcr lb. W = work done by system, ft-lb. per lb. An energy balance on the fluid itself gives: U = ?TdS - ?PdV + etc. [3] in which T = temperature, deg- R- S = entropy, ft-lb. per deg. R. per lb.

Jan 1, 1945

By B. W. Prof. Frazier

I PROPOSE in this paper to treat of the chimney merely as a heat engine, as one of the devices resorted to in practice for the conversion of heat into mechanical work. For the sake of simplicity and clearness in the discussion, let us consider the subject in its simplest form. Conceive a chamber, heated from without, in free communicatioH at one end with the external atmosphere, and at the other end opening into a vertical chimney. Let the. cross-section of the chamber be so great, relatively to that of the chimney, that we can neglect the actual energy of the air passing through the chamber. We will neglect, also, all passive resistances to the passage of the air. We will assume that the cross-section of the chimney is constant, and that the air in passing through it neither gains nor loses heat. The following symbols will be employed in the discussion : Po = the normal pressure of the atmosphere, which, it is assumed, is the pressure existing at the level of the chamber. Po = 10332.96 kilograms per square meter. P2 = the pressure of the external atmosphere at the top of the chimney. To = the, absolute temperature of melting ice by the centigrade scale. This is assumed to be the temperature of the external air at the level of the chamber. To = 273°. T2 =the absolute temperature of the air as it passes from the chamber to the chimney. T3 =the absolute temperature of the air as it issues from the chimney. to, t2, t3 are the temperatures, as recorded on the centigrade ther¬mometer, corresponding to the absolute temperatures To, T2, T3 re-spectively to = 0° C. In general, t = T- 273. Io, I2, I3, represent the intrinsic energy of the air at the temperatures To, T2, T3 respectively.

Jan 1, 1882

By Theodore W. Robinson

WHEREVER the amount of work renders it practicable the plan of using permanent standard solutions, in connection with the colorimetric carbon test, affords such manifold advantages that it is to be strongly recommended. That it has not attained a wider and more general application, is mainly due to the fact that, as the method is generally employed, the difficulty attending the production of the colors, and their doubtful stability when produced, have been only too evident to those who have undertaken their composition. The old method of using standard solutions made from sugar, coffee, etc., has always been hampered by the tendency of the colors to change upon exposure to the light, and the consequent liability to serious error, unless they are closely watched. Appreciating these difficulties, while recognizing the desirability of permanent colors, Mr. Magnus Troilius, at the suggestion of Prof. F. L. Erkmann, investigated the properties of cobalt, copper and ferric chlorides, with the view of determining their efficacy in the production of standard solutions. His results, as obtained, seem to have been satisfactory, but his treatment failed to eliminate many of the objections that have rendered the use of organic colors undesirable. The

Jan 1, 1888

By B. J. Steblay

Roof bolts are the primary means of supplemental support in coal mines and are widely used in other mines. Presently, post installation loads are measured infrequently on only about 10% of the bolts by using standard torque wrenches that limit accuracy to about ± 30%. Because mine roof bolts are long, slender, non-uniformly sized, roughly forged, placed in a difficult environment, and subject to severe bending on installation, researchers have been unable to use ultrasonic reflection techniques to measure strain. A complete measurement system has now been assembled by the US Bureau of Mines, Denver Research Center. Obstacles such as bolt preparation, transducer mounting, reliable reflection, and calibration have been dealt with. The seemingly simple concept of measuring the time of flight of an ultrasonic pulse to a reflector is actually complex due to the need to measure to 0.0025 mm (0.0001 in.) accuracy, the sensitivity of velocity to temperature, and stress, and the stability required to make measurements over several years.

Jan 1, 1986

By J. H. Swisher

ALUMINUM deoxidation equilibrium in liquid iron has been the subject of many investigations. Sawamura and Sano1 have written a critical survey of the literature on this subject and consider the data of Gokcen and chipman2 and of d'Entremont, Guernsey, and Chip-man3 to be most reliable. The present study was undertaken to check these data and extend the range of the experiments to lower temperature. The experiments consisted of equilibrating 5-lb Fe-Al melts with recrystallized alumina crucibles at 1580o + 10oC, and analyzing the solidified ingots for aluminum and oxygen. The electrolytic iron stock contained 100 ppm C, 20 ppm 0, and trace amounts of other elements.* The stock was induction-melted in an atmosphere of 5 pet H2 in argon to attain equilibrium between the melt and the crucible. The temperature was measured with a W, 3 pet Re/W, 26 pet Re thermocouple, and the equilibration time was about 4 hr. The results are plotted in Fig. 1 along with curves obtained from the data of d'Entremont et al.,3 for temperatures of 1740o and 1910°C. The present results can be seen to be consistent with the previously reported high-temperature data. The reaction under study is AI2O3 (s) = 2 Al (l) +3O [1] for which the deoxidation product is Kl =[% Al]2 [%O]3 [2] (Under the experimental conditions, Fe A12O4 is not expected to form.4) In Fig. 2, values of log Ki evaluated at 0.01 pet A1 are plotted against 1/T, using data obtained from all the investigations under consideration. The deoxidation product is plotted in Fig. 2 in lieu of the equilibrium constant (normally obtained by evaluating Ki as pet A1 — 0) because of the uncertainty involved in extrapolating to zero concentration. The difficulty in extrapolating the present data for 1580°C is apparent curvature in the log Ki vs pet Al plot. This curvature is perhaps due to the uncertainty in oxygen analysis for concentrations of 5 ppm and below. For the data of Gokeen and chipman,' the extrapolation is also difficult because of experimental scatter. The line drawn through the points plotted in Fig. 2 may be represented by the equation:

Jan 1, 1968

By Robert Job

Up to five years ago the pig-iron used by the Philadelphia & Reading Railway Co. had been obtained solely upon the appearance of the fracture; but as the service was unsatisfactory, an investigation was made to determine the quality best adapted

Jan 1, 1905

By D. V. BURR

THE ORIGINAL HUDSON RIVER TUNNEL. NOT quite forty years ago a man of uncommon character entered New York. He had several hundred thousand dollars earned by railroad building in the Nest. He was not an engineer, but he had ideas of engineering work which he was destined to prove correct.. He introduced new ways of tunneling, but his plans had only one distinguishing feature-they were simply interesting as showing how such work could be done; they added nothing to the science, have never been used since his clay, and never will be used again. Engineers of repute ridiculed his proposition ; he was an Ishmael in the profession. But if engineers looked askance at him, he certainly returned their contempt in the heartiest fashion, and had no hesitancy about expressing his views of them individually and collectively. This worked to. his disadvantage when he afterward tried to raise the means to go on with the work. He found that the opinion of engineers was respected by financiers, and that money would not flow contrary to their advice. While his conception of large constructions was distinguishingly original, much more marked was his method of demonstrating the feasibility of, his schemes. In the present clays of great undertakings it is the custom to make the other man pay for the experiments. But the man from the West had other notions of how the thing ought to be done. Having wonderful confidence in his own ability and in his perception of the task before him, he used up all his own money before seeking outside assistance. By building several hundred,, feet of tunnel he proved the correctness of his theory, and the tunnel then dug forms a part of the present tube. The result-he failed to finish the tunnel. He was blind in

Mar 1, 1908

By Kenneth J. Kurry

12.2-1. Introduction. Successful management constantly strives to improve its methods and equipment in order to produce a better product at reduced cost. It is not enough that managers be cost conscious and industrious in these days of rapid, dramatic technological development. They must keep abreast of these developments-new or improved methods, machines, and equipment. Most of the machines and equipment have been carefully designed and perfected by reliable companies. However, improvements and progress often evolve from a definite need and are most successful in a particular operation. What may be the "answer" to the requirements of one company may be totally useless or inefficient to those of another. The manager of today must continuously evaluate the myriad proposals for change that result from modern technology-in terms of the particular needs and objectives of his company-to determine correctly which will best satisfy those needs and reach those objectives. Each new method or piece of equipment must receive careful study to make certain it is compatible with the entire operation. It may solve a problem in one department only to create a new problem in another. There are many pitfalls to be avoided in obtaining the necessary facts, and often these problems are unrelated to the actual use of the equipment or method being studied. All facets of the operation being considered must be thoroughly studied to determine if the method is compatible to the entire operation. For example, in considering a possible recommendation that a certain method and type of equipment be used to transport ore, some of the factors that should receive close scrutiny are: blasting procedure, maintenance, turning radius, percent grades, weather extremes, dumping problems, tire problems, length of haul, operator acceptance, or mismatched equipment. Failure to consider every factor-large and small, present and future-in evaluating a proposed change can mean a large investment in a new method or machine that will have to be continued for years at higher-than-antici-

Jan 1, 1968

By Henry Kreisinger

IN evaluating coals as steaming fuel on the basis of chemical and physical properties of the coals, the only properties that can be used are those for which the methods of determination are well established and standardized, and those that affect all methods of burning the coals in the same way. The discussion is written from the standpoint of the coal consumer. The production of steam is the largest field for the use of coal. It includes stations for generating electric power, central heating plants, industrial power plants where steam is used for power generation, factory processes and heating. The field also includes steam locomotives. Small house-heating boilers are not included in this field because such small boilers generally burn specially prepared domestic fuel. The plants using the steam coal are equipped to burn the coal when fired by one of the three general methods: namely, hand, stoker, and pulverized coal. The hand firing is now restricted to small plants and to locomotives. Central stations and larger industrial plants use either stoker or pulverized-coal firing. Some locomotives also use stokers. Pulverized-coal firing has been tried in locomotives but so far its adapta-tion to this use has been handicapped by practical difficulties. The coals used for steaming purposes are generally of the bituminous and semibituminous classes, with volatile matter ranging from 15 to 35 per cent. Coals belonging to these classes are produced in many parts of the United States and form by far the largest part of the total coal production of the country. The value of any coal as fuel for steaming purposes depends on the following factors

Jan 1, 1935

By D. R. McCord

Data of a known statistical quality has been successfully used in a system of conventional fluid mechanics equations essentially free of empirical "conformance factors to prediet early detailed field 03 in a reservoir where gravity drainage is important and oil and rock properties vary con. siderably. The system is useful where comparative recovery predictions for one or more cases of natural depletion and gas cap pressure maintenance are needed and the reservoir is not too heterogeneous. INTRODUCTION Many authors, have examined various facet* of the gravity drainage-gas cap pressure maintenance problem over the last several years. Two of them. Burtchaell and Elkins, have published practical studies. In the case described in the present paper the best development and operating plan for one of the important reservoirs of the Bolivar Coastal Field in Western Venezuela was urgently needed. It was requested that sound comparative economics be presented along with an engineering evaluation of no additional drilling, maximum drilling. several cases of gas pressure maintenance, of water flooding and combination cases. A rapid analysis of the effect on recovery of the range of crude and rock properties indicated that none of the published methods using average properties would yield adequate comparative predictions. This paper covers the predictive system developed to deal with natural depletion and gas cap pressure maintenance. The large amount of data available for this field permitted statistically reliable correlations to be made of most rock and oil properties, and the evident smooth areal variations of these properties encouraged the construction of a lineal mathematical model of material balance and fluid flow equations, which could be manipulated by a modified iterative procedure. The manipulation is much more adaptable to computing machines than manually operated calculators and subsequent studies have been prepared for the IBM Card Program Calculator. A matrix as opposed to linear model has been tentatively worked out by other members of our group to deal with more heterogeneous reservoirs. It is more adaptable to computers such as IBM-701 or the Remington-Rand Univac. In 1950, when the system reported below was developed, no rapid computing machines were available to the author. Their existence and promise encouraged an initial approach by hand. Some details of oil and rock Property correlation are included because there are a surprisingly large number of medium-sized reservoirs in the world that show systematic property variations which are significant for a rigorous analycon. All large reservoirs (over half a billion barrels recovery) with which the author is familiar contain at minimum a significant temperature variation. Using the rock and oil property correlations, past pressure and production, the gas-oil ratio history of the reservoir was computed and found to be in close agreement with field measurements. The future performance under cases of natural depletion, gas injection of 100 MMcf/day, and of 130 MMcf/day, was then computed; a 70 MMcf/day case was also carried far enough to provide data for comparative economics. The 130 MMcf/day case proved to be the most attractive. A 50,000 horsepower gas turbine driven centrifugal compressor plant to take this quantity of adjacent field gas from 30 to 1,950 psia and inject it into the reservoir is under construction. The total cost of the project will exceed 20 million dollars.

Jan 1, 1953