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By A. L. Bollens, R. H. Johnson

The appraisal of oil wells, now that we have the age-size method of making composite decline curves, and the present worth of successive time units method of valuation, has its greatest remaining uncertainty in the difficulty of extending into the future the price curve and the composite production curve. The point of attack in this paper is the carrying on (or extrapolation) of the production curve. Led by the valuable discovery of Lewis and Beal that the decline curve is nearer the hyperbolic class, y = (x + a)-", than any other form, the current practice is the graphic method. The data are plotted on logarithmic paper and shifted with successive trials until the line becomes straight. This straight line can then be extended into the future. The method was a great help during the period when, for tax purposes, there was need for a quick method even though the errors were large. Now that we seek greater validity in our methods we find the following faults with the current method. 1. Where the shift is great (it exceeds 10 in some cases) the scale cannot be read with the necessary precision so that the resulting data would give a very irregular and inaccurate curve. 2. Where the curve cannot be straightened on logarithmic paper because of sigmoid shape the method has a serious systematic error. We believe the sigmoid curves to be more common than usually supposed, indeed when one considers the number of variable causative factors this is to be expected. We have therefore been seeking a method that is free from these difficulties and yet not so laborious as fitting a curve to the data and the calculation from the formula which, since it involves looking up logarithms, is unduly time-consuming. The method here described has been developed on the basis suggested by Earl Oliver, that the amount of oil produced per month or year for each reduction of production of a barrel of oil per day could be plotted to advantage. A step forward was made by Earl Carpenter in this laboratory, and some of the

Jan 1, 1928

By R. S. Handy

The No. 2 unit of the West Mill of the Bunker Hill & Sullivan Mining & Concentrating Co., which went into commission Apr. 17, 1912, is structurally a twin of the No. 1 unit, which was started Nov. 9, 1909. Up to the point where the ore enters the concentrating-de-partment, it follows precisely the process described by G. Cae-tani in his article entitled, Milling of Lead-Silver Ores,' under the heading, Preparation of the Mill-Ore. The process from this point forward, in the No. 2 section, is outlined on the accompanying flow-sheet. In describing it I shall attempt to analyze the products of each separate process. The constancy of the tonnage and the uniformity of the quality of the feed render this practicable. No. 1.—550 tons of feed, all having passed 30 mm., is washed into two 15-mm. trommels, 4 ft, in diameter, 60 in. long, 17 rev. per min., 1 in. slope, 3/8-in. gauge steel.

Jan 1, 1913

By Paul A. Beck

IN several recent investigations1 ' considerable evidence was accumulated to show the predominance in various face-centered cubic metals of a certain relative orientation, corresponding to a rotation of 30" to, 40" around a [111] axis, between a matrix with a strong single orientation texture and grains growing in this matrix." This relative orientation was found to occur both in recrystallization and in coarsening, "secondary recrystallization", so that one is inclined to look for an explanation applicable in both cases. The abundance of growing grains in the described orientations proves that suitable "nuclei" are present in the matrix material and that they have the capacity to grow. The scarcity of growing grains in other orientations may be explained in one 'of two ways. Either the number of nuclei or the rate of growth must decrease strongly for orientations deviating from that predominating among the growing grains, Fig. 1. Both the "oriented nucleation" and the "oriented growth" theory found support in the literature. Because the frequency of nuclei as a function of orientation is in most instances not amenable to direct experimental investigation, a definitive decision is difficult to achieve. However, it is now known with great certainty that the rate of boundary migration is strongly dependent on the relative orientation of the two grains meeting at the boundary and that the orientation favored by high boundary mobility closely corresponds to that predominating in most cases of recrystallization and coarsening. Thus, it was found that, in general, the mobility is very low for boundaries between grains of nearly identical orientation, or for coherent twin boundaries. On the other hand, the boundaries between two grains of a relative orientation correspending to a [1111 rotation of 30" to 40" have the highest mobility in face-centered cubic metals. If a large variety of nucleus orientations are produced grow- by means of a highly inhomogeneous local deformation, nuclei close to the above orientation are found to grow fastest.z4 In view of this evidence and of the fact that the preferred orientation relationship is the same in recrystallization and in coarsening, the oriented growth theory appears by far the more promising one. Since the origin of nuclei in primary recrystallization is certainly different from that in coarsening, the occurrence of the same orientation relationship in the two processes would be difficult to explain on the basis of oriented nucleation. other advantages of the oriented growth theory are its capability of accounting for the often observed sharpening of the texture in coarsening, and its suitability for explaining the role in the formation of the ''cube texture,, of the most important variables, such as the degree of rolling, the penultimate grain size, and the time and temperature of the last anneal: No similarly consistent explanation of all these effects has ever been offered in terms of oriented nucleation. An important problem in connection with the oriented growth theory is the following: In the ce-c entered system there are four [111] axes and

Jan 1, 1952

By Byron Johnston

IN 1926 I had occasion to make numerous measure-ments with a Pitot tube. The differential gage was mounted in a box, and since the work entailed setting upon girders, staging, and flues of various shapes and slopes, much time was generally expended in getting the box blocked into the level position. This inconvenience was so considerable that I devised the gage stand shown in the accompanying illustration. The gage is bolted to the board seat, the bolt per-mitting unlimited adjustment in the plane of the paper. The seat, carrying the gage, revolves on trunnions, per-mitting unlimited adjustment in a second plane, per-pendicular to the first. Consequently, the stand may be stood up, hung by one corner, leaned against some-thing or simply laid down, and the gage levelled from any position. On uneven surfaces, where the stand naturally rests on only three of its legs, it may be swung in the manner peculiar to the tripod, bringing the center of gravity within the triangle formed by the legs, thereby providing a firm set-up. Rubber stoppers under compression were found to give sufficient friction to hold the seat in the desired position.

Jan 3, 1928

By Earl Kennedy

The Northern West Virginia Region of Consolidation Coal Company consists of ten underground mines. The Pittsburgh seam of coal is being mined. This seam is approximately seven feet in thickness in our area. The mining equipment consists of twelve longwall systems and a combination of Joy and Jeffrey ripper type miners. There are a few boring type machines still in use, but these are rapidly being phased out. The auxiliary ventilation fans being utilized vary in type from single stage carriage mounted 20 horse-power Joys to 40 and 50 horsepower two-stage Joys, Buffalo Forge, and Peabody brands. The particular fans that we have primarily been working with on noise reduction are the two-stage 40 and 50 horsepower types.

Jan 1, 1982

By Chris Weyand

Throughout the past 40 years we have been drawing inevitably closer to the conclusion that coal will be our chief source of energy. Our reserves of natural gas and petroleum, on which we depend, are dwindling. Knowing that we will soon reach our physically extractable limit of these energy sources. The US government has created many incentives to encourage energy companies to transfer technology and resources from natural gas and petroleum to coal. Such encouragement is stimulated through taxation methods. Coal mining engineers deal mainly with production, which involves planning and design throughout the acquisition, exploration, development, production, and reclamation of a mine. Though taxation is not one of the areas analyzed by the engineer, it should be considered and understood as it is involved in the mine life cycle. This paper will discuss coal taxation in the five stages of mining and will explore certain tax saving decisions.

Jan 1, 1983

By H. Engelmann

THE very extensive development of a brown coal formation, in the region of the Rocky Mountains, is well known to all of you. The existence of these coals was known years ago, but they were of no practical importance until within a few years, when the mineral wealth of that country began to be developed and railroads were built. As their qualities became better known, their adaptability to domestic manufacturing and metallurgical purposes was more appreciated. They are still much undervalued, although they are mined at some points on a very extensive scale. A large portion of this coal formation is of cretaceous age, while it appears to extend into the tertiary epoch; but whatever difference there may be in the ages of these coals of different localities, they all have some common characteristics which distinguish them from our Eastern stone coals of the

Jan 1, 1876

By H. Engelmann

The very extensive development of a brown coal formation, in the region of the Rocky Mountains, is well known to all of yon. The existence of these coals was known years ago, but they were of no practical importance until within a few years, when the mineral wealth of that country began to be developed and railroads were built. As their qualities became better known, their adaptability to domestic manufacturing and metallurgical purposes was more appreciated. They are still much undervalued, although they are mined at some points on a very extensive scale. A large portion of this coal formation is of cretaceous age, while it appears to extend into the tertiary epoch; but whatever difference there may be in the ages of these coals of different localities, they all have some common characteristics which distinguish them from our Eastern stone coals of the

By R. M. Murray

Although blister copper has been produced at the Mount Lyell Mining and Railway Company's works since 1896, it is only during the past five years that electrolytic refining has been undertaken locally, this having been done previously at customs refineries, at first in the United States, and afterwards at Port Kembla, New South Wales. Left to right: smelter building, converter building, blower building (in which converter-generators are housed), tank house and anode dock. Wire-bar furnace building in background at center. Possessing a hydroelectric power plant capable of generating power considerably in excess of the requirements of its mines and works at the time, the company was in a favorable position to undertake its own refining work, provided this advantage was not offset by the high cost of coal, which would have to be imported from the mainland, and provided also that the capital cost of the plant would not be unduly large in regard to the relatively small amount of copper to be treated. A study of these several conditions led to the adoption of a high-density plant using blister-copper anodes and equipped with an electric boiler to provide any

Jan 1, 1934

By Rudolph G. Wuerker

The scarcity of values of tensile strength of rocks has been explained by the lack of successful testing procedures. In the case of mine rock a description is given' of the difficulties encountered in testing a cylindrical specimen, such as a core, by conventional methods. Over a period of years the following method has given definite and reproducible results with the weakest as well as with the strongest rocks. It does not completely supersede the use of cores with special fixtures but is a supplement in all cases where cores cannot be obtained, as from soft rocks, or in cases where it is less expensive to prepare test specimens by cutting them out of the rock instead of drilling cores.

Jan 2, 1955

By D. Ott

Results of a research project on investment or lost wax casting will be presented. The project was concerned with various aspects of the process as they are typical for the production of jewellery from gold alloys. During these investigations testing methods for investment quality as well as for casting quality and the various process parameters were developed and charateristic defects as they occur in practice were traced back to their origin in the process. Investigated were various static casting and centrifugal casting methods in different atmospheres as well as vacuum casting in devices of different design. It was shown that independent of the method a close control of the many process parameters interfering with each other is essential for a quality casting.

Jan 1, 1984

By R. E. Reed, C. J. McHargue

Poly crystalline aluminum specimens having random and diffuse (001) initial orientations were reduced 90 pct in area at room temperature by drawing, extruding, and swaging. Although each procedure produced the duplex (001)- (111) texture, there were marked dqferences in the relative amounts of each component. This also produced variations in the tensile properties of the aluminum rods. It is generally agreed that the fiber texture found in aluminum rods consists of a strong (111) and a weak (001) component after reductions in area of 90 pct or more. An examination of data summarized in recent reviews'-3 shows much spread in the values for the relative amounts of the two components reported by different investigators. That the initial orientation has a marked influence on the final texture even after reductions in area greater than 90 pct is well-documented.4-7 Another factor which may influence the relative amounts of the two components is the method of fabricating the wires or rods. Barrett and ~assalski' state that the center of wires formed by rolling, swaging, and drawing have the same textures. The data cited in support of this conclusion came from qualitative X-ray techniques. In recent years there has been renewed interest in correlating the type of preferred orientation with such parameters as stacking fault energy and onset of mechanical twinning.'' Since these analyses have often used many sources of data, it is essential that the data be evaluated for the effect of fabrication variables. In this study we have produced aluminum rods by drawing, swaging, and extruding and have quantitatively determined their textures. All specimens had the same purity and fabrication temperature, and the amount of deformation and the starting textures were determined. We have compared our results with published studies on similar materials and fabricating parameters. We have also compared results from the same three fabricating procedures for single-crystal specimens in three instances. EXPERIMENTAL PROCEDURE The aluminum was 99.99+ pct with the only detected impurities being (by weight) 0.002 pct Cu, 0.001 pct Si, and 0.001 pct Mg. Cylinders a in. in diam by 1 in. long with a fine-grain random texture were made by the following method. Cubes 1+ in. on a side were machined from 2-in.-diam ingots. These cubes were slowly pressed about 30 pct in each of the cube directions. The material was recrystallized by annealing 1 hr at 350°C. Three deformation-anneal cycles produced the desired material. Polycrystalline specimens with a diffuse (001) texture were made by casting into a graphite tube 1 in. ID, li in. OD, by 8 in. long which had been preheated to 900°C. One end of the tube was placed on a water-

Jan 1, 1969

By E. H. Sellards

PHOSPHATE rock like most other mineral substances is found in nature in varying degrees of purity. Of the impurities that are present some are constituents of the rock itself; others are inclusions of a foreign substance within the rock; while still others represent merely associated materials or minerals, either clinging to the rock or found in cavities and natural depressions, and hence largely removed in mining. Some of these impurities are distinctly deleterious to the processes of manufacture for which the phosphate is mined, while others, although neutral in action or nearly so, yet by their presence reduce the average grade of the rock and thus acid useless bulk to the shipment. It is the object of refined processes of mining to bring the product, as delivered from the mine, to the highest possible grade consistent with the market requirements and demands. This, however, is not accom-plished without actual loss in the form of discarded phosphate. It is evident, therefore, that the devising of methods for reducing this loss in mining, and yet maintaining the grade of the rock which the market requires, is one of the serious problems that the producers have to face.

Jan 9, 1914

By Lawrence Wright

ON the steep slopes of the Kootenays, 15 to 20 miles south of Nelson, B. C., are a number of ore occurrences (Fig. 1). One that has many features of mining and geological interest is the Ymir Yankee Girl Gold Mines Limited. Discovery of this property was made in 1899 at an outcrop on the hillside, some 2500 ft. above the village of Ymir. This proved to be a branch vein 20 ft. long leading to two main veins, the Yankee Girl and the Spur (Fig. 5). The ore pattern as now delimited shows a remarkable increase in ore area with depth below the outcrop. This recent development is of interest particularly in view of the fact that the property was nearly con-demned, professionally. Another interesting feature, which has a bearing upon its history, is the persistent excess of tonnage produced from period to period over visible reserves. This is not ascribed to lagging mine development, but to detailed vein characteristics, which we will endeavor to make clear by giving a description of the veins and their surroundings.

Jan 1, 1938

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

Jan 7, 1919

By Forbes K. Wilson

"For his vision, determination, dedication, and leadership in the conquest of the remote and rugged Ertsberg and the technical and human barriers to its development and for his lecture ..." It is a great honor for me to be included among the Jackling Award recipients, many of whom have been close friends and associates. My subject is the development of the Ertsberg, a copper mine located 4' south of the equator, 70 miles (113 km) from the south coast of Irian Jaya---the easternmost province of the republic of Indonesia at an elevation of 12,000 ft (3658 m) in an area which was inhabited by a few "stone age" people when I first arrived there in 1960. Persistence, tenacity, immagination and innovation were all required to bring the Ertsberg into production. The technical, financial and political problems that have been faced over the past 16 years were unique in many respects. I hope that my paper will give some encouragement and help to future developers of mines in difficult and inhospitable surroundings.

Jan 1, 1978

By F. F. Aplan

The past year has been another year of vigorous fundamental research in mineral processing as evidenced by the active publication of results, particularly in Germany, Japan, United Kingdom, United States and USSR. It was also noteworthy for several significant meetings and conferences. The Basic Science sessions at the AIME Annual Meeting continued to attract an increasing audience and the sessions were especially notable for the active discussion of papers. The third Engineering Foundation Conference on Particulate Matter Systems,1 chaired by F. F. Aplan, was held in Milwaukee in August and attracted over 100 experts from five continents. Sessions at this week-long conference covered comminution, particle characterization, separation of fine particles, fluid-solid separations as applied to pollution control, flotation kinetics, particle-particle interactions and particle agglomeration. This popular conference will be continued under John Karpinski of Bethlehem Steel Corp. as 1968 chairman.

Jan 2, 1968

The suggestions of the members of the Institute are very much desired by the Committee on Nominations prior to deciding upon its nominations to fill the places of those officers who retire early in 1917. The Committee must make its final report to the Board of Directors early in October. The members are, therefore, asked to send in promptly their suggestions for Directors as well as for Vice-Presidents and President. The Committee hopes to hear from a large number of the members. The officers to be elected at the annual meeting in February, 1917, are: One officer, known as Director and President. Two officers, known as Director and Vice-President. Five officers, known as Director. The attention of members is called to Articles V and VII of the Constitution, and to By-Law XIII, which reads as follows: "The geographical districts to be considered by the Committee on Nominations shall be as follows, until otherwise ordered by the Board. District No. 1. New England, New York, and-New Jersey, excepting New York City and district, which is provided for in the Constitution. (N. B.-New York City and district is designated District 0.)

Jan 7, 1916

The suggestions of the members of the Institute are very much desired by the Committee on Nominations prior to deciding upon its nominations to fill the places of those officers who retire early in 1917. The Committee must make its final report to the Board of Directors early in October. The members are, therefore, asked to send in promptly their suggestions for Directors as well as for Vice-Presidents and President. The Committee hopes to hear from a large number of the members. The officers to be elected at the annual meeting in February, 1917, are: One officer, known as Director and President. Two officers, known as Director and Vice-President. Five officers, known as Director. The attention of members is called to Articles V and VII of the Constitution, and to By-Law XIII, which reads as follows: "The geographical districts to be considered by the Committee on Nominations shall be as follows, until otherwise ordered by the Board. District No. 1. New England, New York, and New Jersey, excepting New York City and district, which is provided for in the Constitution. (N. B.-New York City and district is designated District 0.) District No. 2: Pennsylvania.

Jan 6, 1916

By P. O. Metz, E. L. Wiehe, J. S. Foster

BASED on their analyses of growth kinetics, ibbs' and Harris et al.' have recently proposed that the rate of subcritical graphitization of steel is controlled by the rate of diffusion of carbon in ferrite. illert has concluded that this is the rate controlling growth mechanism when the growing graphite particles are relatively large. Harris et al.' also propose that the matrix surrounding a growing graphite particle is plastically deformed to make room for the growing particle. If this plastic deformation does occur, then preferred recrystallization may be observed around the larger particles. If diffusion of carbon in ferrite is rate controlling, then a graphite particle growing in a matrix of, say, tempered martensite or pearlite, should be surrounded by a carbide depleted zone. Thus, the simple metallographic experiments reported here are sufficient to determine whether or not diffusion of carbon in ferrite is the dominant mechanism for the growth of graphite in steel. The present investigation considers graphitization in five alloys. The compositions are given in Table I. Graphitization was carried out at three temperatures: 900°K (627"C), 950°K (677"C), and 990°K ('717°C). Samples were reacted in both the martensitic and the pearlitic initial conditions. In the hypoeutectoid steels, Sets 7 and 8, .and in the hypereutectoid Fe-C binary, Set 6, graphitization was very limited after 1000 hr at temperature. In these samples graphite particles observed were less than 10 p in diam. In the hypereutectoid commercial steels, Sets 1 and 3, large graphite particles (100 p) did not appear until after 250 hr at temperature. The limited number of graphite particles observed and the range of sizes obtained prohibited measurement of growth rates in this investigation. However, in all samples showing graphitization, neithe a carbide depleted zone nor recrystallization was observed. illert's model predicts that diffusion of carbon in ferrite should become dominant for graphite particles larger than about 300 p in diam. The largest graphite particle observed in this investigation was approximately 450 p in diam. No evidence of carbide depletion was noted. Fig. 1 shows a typical graphite particle. This nodule is from an initially pearlitic sample from Set 3 after

Jan 1, 1970