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By C. D. Rugen

Ground raw material as fed to the cement kiln generally is a mixture of two to four components, each of which may have widely varying physical and grinda-bility characteristics. Chemically similar materials found in the same or different deposits may also differ appreciably in physical properties, depending on their crystalline structure. The calcareous or principal cement raw material may vary from a soft chalky limestone or friable cement rock at one plant to a hard limestone or oyster shell at another plant. Argillaceous materials include clays, shales and granulated slag. Siliceous and/or iron-bearing material, including sand, 'iron ore and cinders, may also be required in addition for certain types of mixes. Frequently differences in grindability characteristics are not given the attention they deserve in comparing grinding results at one plant with those at another or in selecting suitable circuits or equipment. Many types of crushing and grinding units are used, with numerous open and closed circuit arrangements. Both wet and dry processes are used successfully. When rebuilding or installing a new grinding department, the choice of process or circuit in some cases may be dictated by the nature of the materials being ground but in other cases it may be the result of good salesmanship or a compromise. An over-all evaluation of wet process vs. dry process grinding should not be made without considering the effects on all other *producing departments in the plant. In general, the more recent grinding installations, both wet and dry, have employed closed circuits, but many older open circuits are still in successful operation. In our experience, closed-circuit raw grinding pays, because of lower power consumption and less operating labor per ton of product. However, some dry open-circuit mills with improved equipment and operating methods compare favorably in performance with dry closed-circuit units. Character of Ground Raw Mix (Kiln Feed) Grinding in the cement plant in general requires a considerably finer product than in most ore-grinding operations. A distinction between fineness of kiln feed and of cement may be made in that kiln feed preferably should be ground to a limiting size,whereas finished cement should include a range of size fractions including sufficient fine flours to give a product with satisfactory physical qualities. Grinding raw mix for kiln feed therefore is more comparable to ore grinding, although the limiting size is smaller. Most kiln feeds are ground from 85 to 95 per cent passing 200-mesh, depending on mix composition. Some cement chemists believe that raw materials cannot be too fine, since her particles theoretically combine more readily and intimately in the kiln. However, there are certain definite practical objections to extremely he kiln feed, such as loss of kiln dust, unstable material flow through the kiln and greater difficulty in control of chemical composition due to dust loss, and the disproportion of fines from the more easily ground component. Our

Jan 1, 1948

By Stuart M. Buck, J. H. Bramwell, Edward H. Williams

The Southwest Virginia Improvement Company began operations in the Bluestone Flat-Top coal-field, situated in Tazewell County, Virginia, in the fall of 1881. In May, 1883, the company had built 200 coke-ovens, and by March, 188-1, had 9000 feet of entries, exclusive of air-ways, in the Nelson or Rig coal-bed of this district (which here averages eleven feet in thickness), and had extracted 200,000 tons of coal, representing an area of about twenty acres. About this opening has grown the recently incorporated city of Pocahontas, and the completion of the New River branch of the Norfolk and Western Railroad to this point enabled the company to make large contracts for supplying coal and coke, so that it was deemed necessary, on account of the limited area developed, to work the mine day and night to fill orders. At 1.30 Thursday morning, March 13th, the inhabitants of Pocahontas were awakened by a violent shock, and within a few minutes all knew that the East mine had been the scene of an explosion of so general a nature that, of the 114 men at work, not one had escaped. The daily papers gave more or less distorted accounts of the number of victims, the scenes in and about, the mine, and the probable cause of the disaster. At the request of the company, the President of the American Institute of Mining Engineers appointed the undersigned a committee of three to investigate the matter, and the committee thus constituted presents the following report, accompanied by a copy of the testimony taken daring the investigation, for preservation in the archives of the Institute. Pocahontas was reached on Thursday, April 24th, and left on Friday, May 2d. During this interval the committee made repeated visits to the mine, especially to the points, of most importance, examining it carefully in every part; and summoned a number of witnesses, twenty-six of whom appeared and testified. The mine had been left in the same state as when the bodies were

Jan 1, 1885

By A. Schild

The effect of heating a producing well on the rate of oil recovery has been analyzed in the simple case of a well producing oil by a radial drive and in the steady state. Differences of production rates with and without borehole heating have been calculated and plotted; these measure some of the benefits of the thermal recovery process. A striking feature is that the production increase tends rapidly to a constant value for large production rates. Some concrete examples, including a rough comparison with field data. are discussed. Heating requirements have been calculated and plotted on the assumption that the heaters used are 100 per cent efficient. Heating has been thought of as applying only to low volume wells producing heavy oils. However, the calculations suggest that the thermal process considered might be profitable even for some wells producing large quantities of light oil, especially in unconsolidated formations where fracturing is not possible. In the case of wells producing other fluids with the oil or of wells producing partly or wholly by gravity drainage, the theory developed does not apply in detail. It can be expected, however, that any general qualitative be-havior will remain valid. Under normal temperature conditions, high viscosity emulsions sometimes form around the wellbore, lowering the permeability in the vicinity of the well and impeding the production of oil. Borehole heating often prevents such emulsification. This important effect is not easily amenable to mathematical analysis and has not been included in the theory presented here. It should therefore be kept in mind that the benefits due to borehole heating may in fact exceed the values given by the following calculations. INTRODUCTION The recovery of viscous, low gravity oils can often be stimulated by applying heat to the production zone. The higher temperature lowers the viscosity of the oil, increasing its mobility, and therefore its rate of production. One thermal method of recovery 1,2,3,4. consists in operating a heater inside a producing well and, at the same time, producing oil from the well. In this paper a simple theoretical model is analyzed to study the effect of such heating on the recovery of oil. The reservoir mechanics of the process is the only aspect of the problem which is considered here. The details of the heating system are ignored, and it is simply assumed that the heater raises the temperature in the immediate vicinity of the producing well to a pre-assigned temperature T w. Although heating requirements are calculated, these refer only to the heat supplied to the formation and to the oil being produced; they do not include heat losses due to the inefficiency of the heater. A short outline of the theory follows: The heat supplied to the producing well flows out into the formation by means of thermal conduction. At the same time, the flow of oil carries heat by convection from the formation towards the producing well. After sufficient time has elapsed, a steady-state is reached where the temperature, the velocity of the oil, etc., no longer vary with time but are functions of position only. In the steady state the temperature decays like an inverse power from the high value Tw at the wellbore to the original reservoir temperature T. at some distance away from the well. The effect of the high temperature and low oil viscosity near the producing well is the same as if the oil were produced at reservoir temperature To but through a producing well of a larger radius. From this point of view, the energy and money being expended to provide heat

Jan 1, 1958

By N. G. W. Cook

At present, tunnels can be driven in rock by either of two essentially different techniques, in one of which rock-breaking is accomplished by drilling and blasting and in the other by mechanical loading. The methods based on these techniques are comparable in terms of the rates at which tunnels may be advanced, although they differ widely in their range of applicability to different types of rock and lengths of tunnel. The method based on drilling and blasting has reached a high degree of development. It is applicable to even the hardest rocks and rates of advance in excess of 50 ft per day (fpd) are attainable. The main disadvantages of this method are that it involves a sequence of operations punctuated by blasting and that it is relatively uncontrolled, resulting in overbreaking the tunnel profile and damage to the surrounding rock. However, its flexibility, mobility, and low capital cost constitute real advantages in many situations, such as those involving short lengths of tunnel or low rates of advance. Tunneling machines based on mechanical breaking of the rock are a more recent development. They offer a continuous and controlled means of tunneling capable of rates of advance in excess of 100 fpd under favorable conditions. However, these machines weigh many tens of tons and consume several hundred horsepower, so that they are costly and lack mobility. At present, their applicability is limited to long tunnels in relatively soft rock where the high rates of advance and tunnel quality can offset their onerous capital cost. Many situations exist in which the superior quality of a machined tunnel and freedom from blasting would be real advantages, but where the rock is either too hard for existing machines or the length of the tunnel does not justify their capital cost: What are the possibilities of developing cheaper, more flexible, and mobile tunneling machines? Most existing tunneling machines fragment all the rock at the tunnel face to facilitate its disposal. If a machine were used to cut only the profile of a tunnel as one of a sequence of operations, it would be required to break

Jan 1, 1970

By H. P. Schwede, H. G. Doll

This paper describes a method to provide identification of particular depths in a borehole through the use of radioactive markers. The correlation of a marker, placed in the wall of a borehole, with known points of the electrical log and with the casing collars in the cased hole permits accurate positioning of tools with respect to a formation, regardless of absolute depth. Such a process is particularly useful in gun perforation of a casing in a well. Technique and equipment are discussed and illustrated. Examples are given of practical application in the field. Introduction During the past decade the search for petroleum has increased the importance of testing zones at depths in wells which have become progressively deeper. The development of new techniques, such as electrical logging, has permitted the identification of producing formations which consist of comparatively thin strata. When thin beds are to be produced at great depths, the problem of positioning tools accurately to place the well in production becomes acute.l Continuous consideration is being given in the petroleum industry towards the improvement of depth measurements in a borehole. The accuracy in absolute depth measurements, whether made in an open or cased hole, whether determined by a cable or a drill pipe, depends upon a number of factors, such as tension, temperature, and calibration. For example, the effects of tension from the weight of 10,000 ft of drill pipe and the thermal expansion of this length . of pipe, where its average temperature has increased SO"', will Produce an elongation as much as 8 ft.2 The effects Of such factors can be minimized through the use of care in depth measurements, the application of corrections based on experience, and continuous calibration or checking. The fact that different methods and different tools are used to determine the depths of formations in wells will sometimes give rise to a difference between measurements. It is evident that an important requirement in a well is the ability to locate at will any subsurface point. While absolute depth measurements have ion in recent years, it is reassuring to have other means to verify, for example, that a casing is perforated at a particular place with reference to a zone within a formation. Such a check on measurements may be had by placing a reference marker at a point known with respect to the electrical log of the borehole. That point is usually chosen to be in proximity to the 'One to be perforated. Thus, only short in depth measurements are made and any inaccuracy becomes very small and of minor importance' The use of reference markers located at fixed points predetermined in each zone where future operations are contemplated enables the operator to position any tool

Jan 1, 1948

By H. G. Doll, H. P. Schwede

This paper describes a method to provide identification of particular depths in a borehole through the use of radioactive markers. The correlation of a marker, placed in the wall of a borehole, with known points of the electrical log and with the casing collars in the cased hole permits accurate positioning of tools with respect to a formation, regardless of absolute depth. Such a process is particularly useful in gun perforation of a casing in a well. Technique and equipment are discussed and illustrated. Examples are given of practical application in the field. Introduction During the past decade the search for petroleum has increased the importance of testing zones at depths in wells which have become progressively deeper. The development of new techniques, such as electrical logging, has permitted the identification of producing formations which consist of comparatively thin strata. When thin beds are to be produced at great depths, the problem of positioning tools accurately to place the well in production becomes acute.l Continuous consideration is being given in the petroleum industry towards the improvement of depth measurements in a borehole. The accuracy in absolute depth measurements, whether made in an open or cased hole, whether determined by a cable or a drill pipe, depends upon a number of factors, such as tension, temperature, and calibration. For example, the effects of tension from the weight of 10,000 ft of drill pipe and the thermal expansion of this length . of pipe, where its average temperature has increased SO"', will Produce an elongation as much as 8 ft.2 The effects Of such factors can be minimized through the use of care in depth measurements, the application of corrections based on experience, and continuous calibration or checking. The fact that different methods and different tools are used to determine the depths of formations in wells will sometimes give rise to a difference between measurements. It is evident that an important requirement in a well is the ability to locate at will any subsurface point. While absolute depth measurements have ion in recent years, it is reassuring to have other means to verify, for example, that a casing is perforated at a particular place with reference to a zone within a formation. Such a check on measurements may be had by placing a reference marker at a point known with respect to the electrical log of the borehole. That point is usually chosen to be in proximity to the 'One to be perforated. Thus, only short in depth measurements are made and any inaccuracy becomes very small and of minor importance' The use of reference markers located at fixed points predetermined in each zone where future operations are contemplated enables the operator to position any tool

Jan 1, 1948

By E. F. Johnson, F. H. Brinkman, H. J. Welge, A. L. Hicks

A method is presented for predicting the character of gas or water displacement in a radial system, which can be either horizontal or inclined. The latter case would comprise cone-shaped or dome-shaped symmetry. The method conriders the one dimension of radial distance, taken parallel to the bedding planes. Approximate allowance can be made for segregation of the two fluids perpendicular to the bedding planes. A complete saturation history can be obtained in about a day's time with the use of a desk calculator. Results of an example calculation agree well with the performance of simulated gas drive in a large model representing a section of a cone. This pie-shaped, sand-packed model was 8-ft long and 4-in. thick. The method of solution is useful in handling other partial differential equations of first order and first degree. INTRODUCTION A new analytical method has been developed for predicting the performance of gas or water drive in a reservoir having radial or cone-shaped symmetry (see Fig. 1). In addition, this new development offers a general method of handling partial differential equations of first order and first degree. This work extends those methods developed previously'- "or predicting the displacement of oil by gas or water in linear systems. The method of calculating oil recovery in a radial system involves two major parts. The first part is a calculation of the distribution of saturations at various times of depletion. The second part is the calculation of oil recovery and producing gas-oil or water-oil ratios through volumetric balance on the saturation distributions obtained in the first part. This second part differs only slightly in principle from similar calculations made with linear systems, for instance. The basic assumptions used in the calculations are as follows. 1. One-dimensional radial flow. An approach is explained later for approximating a second vertical dimension. (With- drawals of oil, and of the driving fluid after breakthrough, are assumed uniform around the periphery of the dome.) 2. Constant-volume fluid flow. Thus, in a gas drive there is no change in gas solubility, or in oil or gas volume due to viscous and gravity pressure drops. 3. Capillary forces are negligible. 4. Constant rate of injection. A program has been written for carrying out the calculations needed on a digital computer. However, a prediction can also be arrived at using a desk calculator; this latter method of work requires about a day's time for each prediction made. CALCULATION OF SATURATION DISTRIBUTION For definiteness, we describe the development of our method for the case of gas drive from the crest of the structure. The reader will note, however, that the method is just as applicable to an advancing radial water drive. The equation describing gas flow over an infinitesimal

By Charles Behre

UNDER the caption "fault," geologists intend to include all mass movements of solid rocks over adjacent rock masses. When these are studied long after their origin, however, circumstances make it possible to recognize as "fault" only formations showing clear evidence of actual movement of one side with' respect to the other. Necessarily the chief evidence consists of the offset of a vein, bed, or other key structure. Planes of movement parallel to the bedding; or nearly so, are recognized with difficulty or are overlooked and hence many important faults are wholly unrecorded. Indeed, among standard American references on structural geology, one alone emphasizes the importance of bedding-plane movements and that' one only briefly1. For some time the writer, cognizant of this difficulty, has paid special attention to such movements, both as observed in the field and as recorded in the literature. It is believed that enough data are now at hand to justify a short-discussion. Its purposes are fivefold. It is desired first to briefly classify and describe at least the more common kinds of bedding-plane faults, and second, to examine the causes and manner of their formation, at least in instances where the subject has not yet been well covered by other investigators. Third, certain by-products of bedding-plane movements are of such conspicuous importance to the economic geologist and mining engineer as to merit mention. Fourth, concrete illustrations should be placed before the reader in order to lend reality and to furnish a basis of comparison with his experience; such illustrations will necessarily be scattered through the text of this paper. They' are only in part from the writer's own field observations. The fifth and prime objective of this paper is to direct attention to the great importance of movements on the bedding planes, in the hope that the recognition of such movements and their significance may simplify mining problems.

Jan 1, 1937

A GREAT and incomparable speculation is whether the discovery of A compounding the powder used for guns came to its first inventor from the demons or by chance. With this invention he certainly far surpassed all men of every age from the creation of the world up to that day when it was announced by him-men so very learned, indeed like angels and of divine intellect, powerful in every knowledge and power. These had not only revived-arts and sciences and discovered new ones with their intellects, but they had information about all natural

Jan 1, 1942

By C. W. Beattie, R. L. Solter

ALUMINUM-KILLED, low carbon steel sheets are used extensively for severe deep drawing and other difficult forming operations. They usually, but not always, have a characteristic grain structure in which the grains are elongated both in the lengthwise and in the transverse direction. As described by Burns and McCabe,&apos; a typical grain in the plane of the sheet has its two axes in that plane from 1 Y2 to 4 times as long as the axis normal to the plane of the sheet. Rickett, Kalin, and MacKenzieZ have also reported on the recrystallization behavior of such steel. The contrast in grain structures of fully processed sheets of aluminum-killed and rimmed steel is illustrated by Figs. 1 and 2. The elongated grain structure of the aluminum-killed sheet is not developed on all heats or lots of this metal, and studies of the factors controlling and influencing its formation are reported in this paper. Jeffries and Archerb tate that unstrained grains are normally equiaxed, but exceptions are common. For example, if a metal containing a material mechanically obstructing grain growth is subjected to considerable working followed by thorough annealing, it may exhibit grains consistently elongated in the direction of working. Our experiments demonstrate that aluminum-killed, low carbon steel is such a metal, and that the substance mechanically obstructing grain growth is aluminum nitride. The effectiveness of aluminum nitride in inhibiting grain growth has been found to be influenced by the degree of cold reduction, the rate of heating in annealing, the thermal history of the sample before cold reduction, and the residual aluminum content. A correlation between grain shape and austenitic grain coarsening temperature also was indicated and additional experiments demonstrated that aluminum nitride is also the principal cause for the fine grain characteristic of aluminum-killed steels. Manufacture In conventional practice, aluminum-killed sheet steel is manufactured from a low carbon steel containing approximately 0.02 to 0.07 pct residual (HC1 soluble) Al. With the exception of certain samples containing greater or lesser amounts of aluminum, the steels used in these investigations were within the following composition range: C, 0.03 to 0.06 pct; Mn, 0.28 to 0.38; S, 0.017 to 0.032; Al, 0.03 to 0.06; P, <0.01; and Si, <0.01. Properly heated ingots are rolled to slabs about 4 in. thick. After surface conditioning, the slabs are reheated to about 2300°F and hot rolled continuouslv to strip about 1/10 in. thick. The strip rolling is completed at a temperature of 1550°F or higher, and the strip is coiled, usually at a temperature near the lower critical transformation. After cooling, the strip is pickled to remove oxide, cold reduced 40 to 70 pet to final thickness, then annealed to 1250° to 1350°F in 20 to 80 ton charges, the size of which results in slow heating and cooling rates. Effect of Cold Reduction According to Sachs and Van Horn,&apos; the deformations of the individual grains in rolling are similar to those of the total volume. Thus individual grains would elongate in rolling according to the amount of cold reduction imposed. This is true theoretically, but as cold reduction increases the individual grains tend to fragment, and measured grain elongations become less than theoretical. The amount of grain elongation may be described by a numerical rating based on grain counts made by the intercept method. Specimens are polished normal to the plane of the sheet, with the polished surface extending parallel to the rolling direction. After etching, grain intercepts are counted along a 50 mm line on a micrograph of suitable magnification. In random locations parallel to the plane of the sample 20 counts are made and 20 are made in the thickness direction of the sample the average count in the thickness direction divided by the average count parallel to the plane of the sample gives a numerical rating of the grain shape called grain elongation. For example, a grain elongation of 2.00 means that the average grain is twice as long as it is thick. The average of both counts may be converted to grains per sq mm by a nomograph relating intercept counts and grain count. By the same procedure the grain elongation in the plane of the sheet but transverse to the rolling direction may be determined, using transverse metallographic samples. A comparison of theoretical and measured grain elongation was obtained on an aluminum-killed

Jan 1, 1952

By O. N. Carlson, K. E. Solie

The brittle-ductile transition temperatures of single and poly crystalline chromium metal were studied as a function of nitrogen concentration and chromium nitride distribution. It was observed that In recent years there has been an increasing interest in chromium-base alloys for high-temperature applications. The principal disadvantages, however, have been the difficulties of fabrication and the design problems associated with a material of such limited ductility. Various studies have been the effects noted in the poly crystalline material are essentially reversed in the single crystals. These observations are discussed in terms of existing theories for the brittleness of chromium. conducted recently directed toward a determination of the cause of this brittleness and to find ways for minimizing its effects. Allen et al.,&apos; Wain Abrahamson and rant,&apos; and weaver4 have carried out studies on the effects of interstitial impurities on the brittle-ductile transition of chromium metal of various degrees of purity. These investigations have shown that oxygen has little or no effect on the transition temperature of chromium in all conditions studied but that carbon increases the transition temperature under all conditions tested. Nitrogen was found to increase the transition temperature in the wrought condition and in the quenched or cast conditionS but reportedly has no effect in the furnace-cooled condition.

Jan 1, 1964

By Larry J. Tucker

INTRODUCTION The orebody at Pea Ridge strikes NE-SW and dips at about 800 to the SE. The ore and surrounding rocks are Pre-Cambrian in age. These rocks are usually very competent. Locally strong jointing has caused problems and toward the hangingwall dikes have caused particular problems during or after the open stoping phase of production. About 396 m of sediments lie over the ore. The shape and mineral content of the orebody has been fairly consistent so far with production areas lying from the 1375 to the 2475 levels. The deeper limits of the ore- body haven&apos;t been found yet. The ore is high grade magnetite with a strike length of over 600 m and a maximum width of over 180 m on some levels at the center of the orebody. Production at Pea Ridge for the first three years of operation came from two types of open stopes. The original stopes were recovered with horizontal production rings being drilled and blasted from vertical raises. Later a more typical sublevel stoping method using vertical production rings from one or more drilling sub- levels was used. There were a number of reasons for the selection of open stoping as the initial production method at Pea Ridge. First, it was judged that the ore was not of a block cave quality. After fifteen years of production, this assumption can be verified. There was some concern during the planning days for the potential for high flow rates of water into the mine from aquifers in the sediments lying over the orebody. Dewatering wells from surface and underground were put in as a precaution and nothing came of this potential problem. Open stoping and its resulting pillar structure put off this problem by supporting the sediments a few years longer. For a moderate investment in level development some production from open stoping was quickly realized. The first open stopes were brought in on what was then the bottom mine production level (2275), near the shaft pillar and situated on the footwall. This production practice of stoping on the heels of development from shaft pillar westward and from footwall to hangingwall continued through the open stope phases of production at Pea Ridge for many years. From the standpoint of mine efficiency and pillar stability, this would not seem to be a recommended mining practice. 74 570 w electric slushers, using 1.37 m dippers, pulled the open stope ore out into 18 ton bottom dump cars. Ordinarily five of these cars made up a train, which was pulled to the dump area by a trolley powered electric locomotive. Open stoping had the disadvantage that 100% of the recoverable portions of the orebody had to be developed in order to recover 33% of the ore. 67% of the ore was left behind in a large pillar system. For many years we had no planned method for recovery of these pillars. Mining methods are of course, limited by the existing technology. Advancing technology, coupled with the limited production capabilities of open stoping, low efficiencies and high relative cost early in the history of the operation recommended that other mining methods be looked at. In Sweden, considerable practical experience, coupled with a large amount of theoretical work had become available on sublevel caving. To Pea Ridge it offered the apparent benefits of: 1) The flexibility of diesel powered trackless haulage. 2) The efficiency of two machines to one operator on longhole drilling. 3) A multilevel production picture with a large number of drawpoints for ore recovery. 4) 100% recovery of the mineable portion of the orebody in one production pass, with no pillar recovery problems left behind. This paper outlines the experiments and experiences which Pea Ridge has gone through with sublevel caving from 1967 to this date.

Jan 1, 1981

By Joseph E. Pogue

The past year in the petroleum industry was one of overproduction, rising inventories, low prices, and meagre to vanishing profits. This outcome was the result of a long period of intensive and uncompensated effort on the part of both financial and industrial interests, to stimulate supply on the theory that the primary problem facing the petroleum industry was the development of an adequate reserve of raw material to protect a large and ever-growing investment. The stimulus was applied in various forms and through diverse channels: capital had long flowed into the industry in excessive amounts under the attraction of large expected profits; the price level for crude petroleum had persistently been influenced by speculative considerations, with the result that prices declined slowly in periods of flush production and were quick to advance in anticipation of statistical improvement, thus maintaining a superfluous degree of stimulus on wildcatting and on drilling; speculation in inventories had led to the unsound, or at least unusual, business practice of accumulating huge stocks of oil; and, above all, the industry had directed the potent force of technology to the expansion of supply and achieved radical results in accelerating oil discovery, speeding up the rate of oil extraction, and enlarging the recovery of gasoline and lubricating oils from the raw material. In short, the economic conditions of 1927 were exactly those to which the objectively driven enterprise of the petroleum industry had long been directed; and the undesirable financial consequences arising therefrom reflected no lack of success in what had been set out to be achieved, but rather the failure to have established concurrently the necessary means of economic control to prevent the immediate conversion of reserves into current supply, and likewise the oversight in neglecting to apply the technological force to the enlargement and diversification of the market for petroleum products. Perhaps, when viewed in its longer perspective, 1927 will stand out as the turning point in the economic policy of the petroleum industry, when the technique of rationalizing production made its initial claim for recognition.

Jan 1, 1928

By V. R. Garfias, R. V. Whetzel

It has been repeatedly questioned whether estimates of oil reserves are of any practical value, as the greater number of such calculations previously made have subsequently been proved to be grossly inaccurate. But even admitting partial justification for such statements, it must be evident that some idea, however approximate, of the available reserves of essential minerals—petroleum included—is of vital importance in mapping their development and the future trend of the related industries, particularly if it is kept constantly in mind that these estimates are not only never intended as a final word but must continually be subject to revision in accordance with the changes in their component factors. The value of these estimates, therefore, hinges on the clear understanding of what is meant by reserves and that the figures can only apply within the limited time when the controlling factors remain unchanged. It should be understood, further, that while estimates of possible and probable oil deposits are as a rule but idle conjectures, appraisals of proven oil reserves can undoubtedly be made with an ever-increasing degree of accuracy. And it is with this in mind that in the present study the endeavor has been to estimate only the world&apos;s proven oil reserves and to leave out of consideration the questionable volume of the probable and possible oil reserves. Such a survey presupposes further a clear distinction between the known amount of oil underground in proven fields at any one time, and the proven reserves: the portion that can be economically brought to the surface and made available for utilization. Only a fraction of the petroleum stored underground in proven fields— usually associated with natural gas—is or can be economically brought to the surface, and not all of the oik brought to the surface is economically utilized; also, although practically all the natural gas can be economically recovered and utilized, in actual practice a large part of the total volume that reaches the mouth of the well is wantonly blown into the air and wasted. It is thus estimated that in the United States only some 25 per cent of the petroleum stored underground in proven fields is actually brought to the surface; and in actual practice close to 25 per cent of the total gas produced is now absolutely wasted. And the dissipation of this

Jan 1, 1936

By V. R. Garfias, R. V. Whetzel

It has been repeatedly questioned whether estimates of oil reserves are of any practical value, as the greater number of such calculations previously made have subsequently been proved to be grossly inaccurate. But even admitting partial justification for such statements, it must be evident that some idea, however approximate, of the available reserves of essential minerals—petroleum included—is of vital importance in mapping their development and the future trend of the related industries, particularly if it is kept constantly in mind that these estimates are not only never intended as a final word but must continually be subject to revision in accordance with the changes in their component factors. The value of these estimates, therefore, hinges on the clear understanding of what is meant by reserves and that the figures can only apply within the limited time when the controlling factors remain unchanged. It should be understood, further, that while estimates of possible and probable oil deposits are as a rule but idle conjectures, appraisals of proven oil reserves can undoubtedly be made with an ever-increasing degree of accuracy. And it is with this in mind that in the present study the endeavor has been to estimate only the world&apos;s proven oil reserves and to leave out of consideration the questionable volume of the probable and possible oil reserves. Such a survey presupposes further a clear distinction between the known amount of oil underground in proven fields at any one time, and the proven reserves: the portion that can be economically brought to the surface and made available for utilization. Only a fraction of the petroleum stored underground in proven fields— usually associated with natural gas—is or can be economically brought to the surface, and not all of the oik brought to the surface is economically utilized; also, although practically all the natural gas can be economically recovered and utilized, in actual practice a large part of the total volume that reaches the mouth of the well is wantonly blown into the air and wasted. It is thus estimated that in the United States only some 25 per cent of the petroleum stored underground in proven fields is actually brought to the surface; and in actual practice close to 25 per cent of the total gas produced is now absolutely wasted. And the dissipation of this

Jan 1, 1936

By F. Louis Grammer

The following study of flue-dirt and the influences controlling it may be interesting to many. It is published because it represents observations at about thirty furnaces at different times. It may assist in giving an impetus to the making of similar observations elsewhere. Until ten years ago, the metallic waste in furnace-gases was not considered a problem of pressing urgency in iron metallurgy—certainly not in the blastfurnace end of it. Many plants at present ignore, or pay but little attention to, top-pressures. Prior to the introduction of Mesabi ore, the losses in escaping gases, if considered at all, were regarded as thermal losses, or losses of fuel (except by those interested in lead, zinc, silver, etc.). In a high-priced material like ferro-manganese, such losses were, indeed, considered important. But the behavior of the Mesabi ores, corning, as they did, in practically inexhaustible quantities, could not be disregarded by the furnaceman. These ores came to stay. The tables appended below have purposely been altered to disguise the plant, the company and the ores used. The comparative values are maintained. In these tables, the influencing elements and conditions which are constant, or practically so, namely, size of furnace, quantity of wind, fuel used, etc., are not mentioned. The figures represent observations consistently followed up for a long period. The weights of flue-dirt were obtained from cars on which no other dirt was thrown. The analyses and calculations are based on the best of sampling. The effects of slips are excluded. Slips should not occur at well-regulated or properly-constructed furnaces, excepting under unusual and rare conditions. Allowances are made for moisture, scrap charged and silicon in the metal. The cutting effect of Mesabi

Jan 1, 1904

By John F. Havard, Armine F. Banfield

Sooner or later, we all get involved in the economic study and valuation of a mineral deposit. To communicate clearly the necessary information, we must scrupulously use various terms with specific meaning. All these terms-such as ore, exploration, development, production, reserves, proven ore, probable ore, possible reserves, resources, as well as similar terms applying to coal-are continually on the lips of anyone who reports on the economic aspects of a mineral deposit at the exploration, development, and production stages. The meaning of these terms is even more important in feasibility studies to determine whether a deposit should be put into production. Finally, careless use of these terms in reports published for public financing may, and sometimes does, lead to prosecution of the writer for misleading information.

Jan 7, 1975

By D. McLean

For many pu@oses uniform strength is desired over a long temperature range, coupled to a band of softness at the hot end for easy shaping. Various types of material fulfill such a requirement to different degrees, depending on the regularity of their atomic structure. In long-chain polymers and vitreous glasses the irregular structure leads to a steep temperature dependence of deformation resistance and the temperature band between the hard and brittle condition and the soft condition is only about 100 C. In crystals and especially metals the atomically regular structure leads to a much smaller sensitivity over a wide temperature band, thus approaching the ideal behavim. The reason for this insensitivity is that the regular crystalline structure deforms by the movement of dislocations and the elastic interactions of dislocations in- PLASTICS, GLASSES, AND CRYSTALS The ease or otherwise of deformation varies with temperature much more in some substances than in others. This is an important matter when service over a wide temperature range is needed, especially volve energies of several hundred electron volts compared with which the energy of thermal agitation is insignificant. However, temperature affects a metal&apos;s defmmation resistance through its influence on the annealing, m coarsening, of the three-dimensional dislocation network. This coarsening is a phenomenon very similar to grain growth and ideas about grain growth can be applied to it. Taking into account also the temperature dependence of the glide resistance from alloying additions, a reasonable account can be given of the overall effect of temperature on deformation strength and of stress and grain size on deformation rake. Special structures me described. some arising from these ideas and as yet untried, which may benefit metals and polymers but not ni-treous glasses. when in addition a degree of softness suitable for shaping is required at some stage. It would be nice if one could write on this subject in as much detail about plastics, glasses, and so forth, as about metals, but there has been far more study of this matter in metals than in other substances, which is one reason why most of this paper concerns metals. However, in Fig. 1 there are shown the deformation strengths of several nonmetallic substances as a function of temperature. In many tests the attempt at deformation caused breakage and the graph lines are then drawn dashed. Long-chain plastics, a glass, and a crystalline substance are included in Fig. 1. The notable feature of all of them is the sensitivity of the

Jan 1, 1969

By AIME AIME

DESPITE the fact that its membership is spread over every continent of the globe, the Petroleum Division was able to report a very substantial attendance at its meetings. Careful planning on the part of its chairman, J. B. Urnpleby, and his associates resulted in the presentation of a program that was of timely interest -and led to discussions that will unquestionably prove to be of major value to the petroleum engineer and to the oil industry in general. Scheduling of meetings so as to avoid all conflicts made it possible to obtain a higher average attendance at the several sessions* than in previous years, and gave everyone a chance to hear all of the papers that he was interested in. The chairmen of the various meetings are to be congratulated especially for their skill in handling them so that at .no time was there the least indication of lagging interest.

Jan 1, 1930

By C. M. Fellman

THE over-all picture of safety in mining has been encouraging during the past few years, and in mining activities as a whole the trend in accident occurrence is downward. This is the more noteworthy when the type of labor used in mines during the war period is taken into consideration. The drafting of young mining employees into the armed services and the departure of others for work in other war industries took a heavy toll of young, husky, active men. Their places were taken in large part by older men who returned to the mines, or by inexperienced men with little if any knowledge of mining. Despite the lack of labor and especially of skilled labor, and the difficulty of obtaining new equipment as well as maintaining and replacing worn or broken equipment, and numerous other difficulties the mining industry not only reached and maintained maximum production but made the increase with little if any sacrifice of safety. In fact, in many instances better safety records were. established than in normal

Jan 1, 1946