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Jan 1, 1920

By B. K. Larkin

Solutions to the diffusion equation for a line source located anywhere in a region bounded by a circular discontinuity are presented. Such solutions follow automatically from the Green&apos;s function presented by Jaeger.4 Petroleum industry applications of this problem would include transient compressible fluid flow in porous media bounded by a discontinuity. Since several recent papers have treated the subject in less general form, it would appear that many workers in this area of the petroleum industry are not aware of Jaeger&apos;s work. STATEMENT OF THE PROBLEM In several trearments1,2,3 of the transient flow of compressible fluids in porous media it was convenient to consider a region to be bounded by a circular discontinuity. In such a region (Fig. I), the properties in Region 1, r < a, are constant but different from the properties in Region 2, r > a. Hurst, l using the Laplace transform, obtained solutions for a line source located in the center of such a porous medium. The purpose of this work is to point out that a much earlier paper by Jaeger4 presents the solution for a line source located anywhere inside the discontinuity. The assumption is made that a line source may be used to approximate a well. In the following material it is convenient to use the terms source and well as being equivalent; however, the reader should remember the distinction in applications. SOLUTIONS Jaeger presented the Green&apos;s function for a line source, or well, in the composite region shown in Fig. 1. In the most general form, the solution for a system of j wells in Region 1, each producing at a time varying rate, qi (t), is

By John Cobb

THE attempts of British investigators to arrive at definite knowledge concerning the nature of the nitrogenous constituents of coal have been mainly made through studies of the behavior of coal on carbonization and gasification. There have been carried out numerous determinations of ,the distribution of nitrogen in the products of carbonization under laboratory and large-scale conditions; and by a careful consideration of the extent to which nitrogen is liberated, say as ammonia, at different temperatures and under different conditions of operation as regards atmosphere, it has been possible to form some general notions as to the nature of the nitrogenous compounds present in the coal, and at the same time to arrive at clearer ideas as to what are the important operative factors in determining the ammonia yield under working conditions. This work has been spread over many years and is summarized below. The difficulties of connecting the results in such a way as to allow of the nitrogenous constituents of the coal being described in terms of specific organic structure are great. They arise, for example, in the carbonization process, because the phenomena of decomposition observed at any one temperature can only refer to compounds decomposing at that temperature, each of them with a previous history of chemical transformations occurring at lower temperatures. To put it in another way, the compounds occurring in the coke at any stage are not in the least likely to be those present in the original coal. The same difficulty, in a milder form, occurs when the method of differential solution is attempted. There is always the preliminary question, almost impossible to answer, as to how far the separation by the use of the solvent has involved some form of decomposition of the original compounds. In the following summary, an attempt has been made to bring together results obtained by British workers.

Jan 3, 1925

By P. H. Scott, Walter Rose

Recent papers by S. T. Yuster have called attention to the largely ignored concept that there will be a transfer of viscous forces across fluid-fluid interfaces during the flow of immiscible fluid phases through porous media. This leads to the implication that the relative permeability us saturation function, as applied to each of the fluid phases of the system, will in some way be dependent on the viscosities of all the other fluid phases which are contiguous to the flowing fluid of interest. In fact, Yuster has selected and analyzed the properties of a capillary-tube model of the reservoir-prototype flow systems and concludes from his studies that relative permeability values will be very markedly influenced by the viscosity ratio in two-phase systems. On the other hand, relative permeability data have been reported in the literature for more than 20 years; and where these data are consistent at all, they consistently how no dependence on viscosity ratio (cf. chapter 7 of Muskat3 for a resume of past experiniental work). This paradoxical situation has prompted us to re-evaluate Yuster&apos;s work. The major flaw we find has to do with the properties of the model Yuster employed to give qualitative support to his predictions. This model is defective in that important surface area parameters characteristic of the prototype-reservoir flow system have not been propertly scaled. Fig. 1 shows how we believe Yuster&apos;s model should be modified to circumvent this difficulty. It depicts the capillary tube of radius R and length L, comprised of two elements in series. The first part of length, L has the nonwetting phase flowing centrally out to a radius distance r, where an interfacial boundary exists with the wetting phase which flows in the concentric annular pace of the tube. The second part of length, L-L,. has the

Jan 1, 1953

By R. V. Lundquist

Leaching manganese-bearing materials with NaOH to remove caustic-soluble silica has been demonstrated as a method for up- grading manganese. Those materials containing opaline varieties of silica respond most readily. Spent leach liquors are regenerated by treatment with lime to precipitate calcium silicate and to reactivate the NaOH for leaching.

Jan 4, 1953

By E. Wysocki

In the production of magnesium oxide, dolomitic lime and magnesium chloride are reacted to produce an intermediate product, magnesium hydroxide. Consistent product quality requires close monitoring of the soluble calcium hydroxide level during the reaction. Traditionally, this analysis has been done by manual titration; however, the product quality could improve with more frequent analysis and better control. A feedback control system was developed based on frequent automatic titrations, and reactor modelling was used to discern a control strategy. The system development and implementation are described.

Jan 1, 1984

By Niles E. Grosvenor

Complex underground mining problems are increasing as mining depths increase. Many of these problems have been solved mainly by unsystematized trial-and-error methods based on individual experiences. This system of solving mining problems has resulted in over-cautiousness whereby a large quantity of our mineral resources are left in the ground, or not enough caution with a resultant failure of the underground opening. From studies made of physical properties of rocks, large volumes of data have been collected as a source of finding correlation among the different physical tests or among certain rock types. Most of these studies have not produced satisfactory results because the investigator usually arrives at the conclusion that the results are too scattered to be reliable. The reasons usually given as the cause of this scatter are that rocks are nonhomogenous and non-isotropic. Similar types of poor correlation that were being obtained from compression tests in the Colorado School of Mines Mining Research Laboratory led to an investigation of a good method of making a simple unidirectional compressive strength test.

Jan 1, 1963

By J. J. Pelley

NOT being a scientist, an engineer or a metallurgist, I consider it a very great honor indeed to be asked to address the American Institute of Mining and Metallurgical Engineers. Your program indicates that any lack of intricate and technical knowledge on my part in the field of metals will be well taken care of by others. Therefore, I believe any remarks that I have to make might well be devoted to the practical side of metals in railroad service and to the general railroad situation as I view it today. The experiments now being conducted on the railroads with so-called streamlined, light-weight trains and cars would not have been possible had it not been for scientific and engineering research in the past that made these lighter weight metals available. The railroads now have approximately forty units of these new trains in operation. Experi-ence with them will no doubt be a guidepost for future construction in that direction. While the best known experiments are in the passenger service, they are being extended into the freight service. Within the past three years there was constructed for the Association of American Railroads a new standard box car of ordinary carbon steel, in which, by reason of superior design, weight was reduced by 3500 to 4500 lb. under that of existing cars of like capacity. The Association is now testing a box car that weighs approximately six or seven tons less than practically all of the box cars of like capacity in service today. If these tests are successful a very large field for the use of lighter weight metals will immediately be opened, provided the costs of such metals are not too high. The fact that various experiments are being carried on with other classes of equipment constructed with so-called light-weight and non-corrosive metals no doubt will have a considerable effect upon the rebuild-ing of old equipment. The question then will be: How much can we afford to spend on the rebuilding of an old car weighing six to seven tons more than a new car constructed with the latest available materials?

Jan 1, 1936

By James Bowron

Considering the importance of the steel trade and the strategic position occupied in it by the Birmingham district, it may be surprising to many to learn that the first pig iron smelted with coke was made in Alabama on Feb. 28, 1876, although merchant pig iron had been produced in Rockwood, Tenn., in 1867 -a plant that is still in operation The heavy deposit of Clinton ore, extending from Pennsylvania into Alabama, varies greatly in accessibility, on account of geological changes such as erosion or anticlinal upthrow; it varies equally as much in thickness and in quality. The brown ores extensively scattered through the South also vary materially in quality—some are relatively low in phosphorus and high in manganese, and vice versa. The red ore varies materially in phosphorus, but the iron produced from this ore was always considered too high in phosphorus for treatment by the acid bessemer or open-hearth process and did not contain sufficient phosphorus for the basic bessemer process. Under these conditions there remained only the basic open hearth as a possible process; and for many years it appeared impossible to use this, because, with coke smelted iron, the silicon was too high to permit its use in basic lined furnaces. Various attempts were made, from time to time, to produce a low-silicon iron, by carrying high lime burdens together with harder blowing, but the blast furnaces of the South were not equipped with the blowing power of today and from 31/2to 5-lb. pressure was the normal working condition. The result of these experiments, therefore, was that a furnace would get a lime set or be hastily changed to avoid scaffolding, and engineers and superintendents were careful not to renew the experiments. After the development of the beds of dolomitic stone in East Birmingham, the carrying of sufficient lime to bring down the silicon in the blast furnace to the permissible open-hearth limit was successfully done at the Alice furnace in Birmingham, commencing July 22, 1895. In a very short time the entire output of that furnace was being sold to different Northern steel manufacturers, with a guarantee that silicon and phosphorus should run below 1 per cent.

Jan 1, 1925

By A. J. M. Ross

BACKFILLING of stopes and other underground openings in the Homestake mine with sand tailings was undertaken primarily to reduce surface subsidence, which was wrecking much of the surface plant and a substantial part of the town, and to make possible maintenance of open-ings into the top of pillar stopes as mining progressed. The progress of this type of filling has been rapid and the results very satisfactory. Sand is now used in filling timbered stopes, shrinkage stopes, and abandoned drifts and crosscuts. A permanent pipe-line system for transporting sand tailings into the mine by gravity has been installed. The close filling of all stopes has resulted in important benefits other than the two major ones. The ore bodies in the Homestake mine occur as replacements in one distinctive layer of the metamorphosed pre-Cambrian sediments along a group of minor folds that together form a complex anticline that pitches at 35° to 40° to the southeast. The ore bodies are extraordinary for their magnitude. Widths of over 300 ft. have been mined and continuous ore has been followed for over 1200 ft. along the strike on some of the upper levels. Mining has been by shrinkage stoping with square-set mining of crowns and pillars. In the standard plan, shrinkage stopes 60 ft. in the direction of strike and the full width of the ore have been taken up to within 25 ft. of the level above. After filling, the crown has been mined by square-set methods, as have also the 40-ft. pillars between shrinkage stopes. In former days, when the supply of ore seemed inexhaustible, the mining of pillars was allowed to lag far behind because of the high cost. Many pillars were rather badly fractured on the level and in some places between levels. Coarse waste was used for backfilling all stopes, but in pillars it became increasingly difficult to maintain haulageways for the transporta-tion of this fill over the top of the stopes as mining progressed. The cost of maintaining these crosscuts was excessive and in many pillars prac-tically impossible. Therefore it became the practice to fill pillar stopes by tapping the back and sides of the stopes.

Jan 1, 1939

Jan 1, 1887

Jan 1, 1939

Jan 1, 1939

Jan 1, 1929

By Swapan Bhattacharya

United States federal and state regulatory authorities require underground mine operators to adopt adequate measures to minimize material damage to the surface caused by mine subsidence. This paper presents an approach to define and determine the extent of material damage due to subsidence from underground coal mining. The basic steps involved in the development of adequate criteria have been enumerated together with the approaches and methodologies used.

Jan 1, 1984

The volumes of Transactions, which are published annually, contain the list of officers, rules, etc., the Proceedings, and the papers revised for final publication. (In this revision, after the preliminary publication, authors are permitted to use the largest liberty; and the changes and additions made in papers are sometimes important. It should be borne in mind by those who study or quote a paper in the preliminary edition, that they may not have in that form the ultimate and deliberate expression of the author&apos;s views. It should be added, however, that in the majority of cases there are no important changes.) These volumes are for sale as follows, in paper covers:

Jan 1, 1917

By E. D. Slone, F. L. Dillard

When a new mine is in the planning stages, one of the most important decisions to be made is the selection of&apos; face haulage equipment and the interrelated transportation system to the surface. Equally important is the method of transporting personnel supplies and repair parts from the surface to the working places. When Bell & Zoller management elected to open the new Zeigler mine in the No. 9 seam near Madisonville, Ky., last year, various transportation systems were considered. It was agreed early that a slope mine would be preferred to a shaft mine, and that belt conveyors would be more economical than a rail system.

Jan 1, 1970

By J. S. Li, J. C. Edwards

A prediction is made of the airflow at the Bureau of Mines Lake Lynn Laboratory with a ventilation computer program that accounts for fan-driven forced ventilation and temperature-induced natural ventilation. There was substantial agreement between measured and predicted airflow rates. The capability of the program is demonstrated as a planning aid for ventilation under emergency conditions in a multilevel coal mine. Smoke spread in a multilevel mine is analyzed following the occurrence of two events, the failure of the main exhaust fan and the development of a fuel-rich fire in a passageway.

Jan 1, 1983

By Milton E. Wadsworth, Edward M. Eyring

Better understanding of solid surfaces and their associated adsorption products is of both academic and practical value. The study of detergents and their behavior in cleaning surfaces is fundamentally related to the nature of the products adsorbed and their ability to compete for certain surfaces. Similarly in flotation, the nature of the adsorbate before and after adsorption is basic to clear understanding of the process. The recently developed pellet technique employing infrared spectroscopy provides a powerful tool for the study of solid surfaces. Absorption bands, which are infrared-active, may be observed for adsorbed products. Also any changes in the surface substrate that occur as a result of adsorption may be detected by means of differential spectra

May 1, 1956

By J. S. Smart

The six countries which make up the European Economic Community-Belgium, France, German Federal Republic, Italy, Luxembourg and The Netherlands-are populated by about 170 million consumers. Their economic abilities and their standard of living have increased at a high rate during the past few years. Consequently, the policies and trade practices adopted by the group will have International repercussions within the nonferrous Industry whether or not other nations are eventually admitted to the group. Considering the hopeful prospects of only a few months ago, it is surprising that we must now face up to the fact that Great Britain and Norway, in particular, will achieve membership status only after prolonged and difficult negotiations, if at all. However, this is but one of many factors that should remind us that the Common Market is yet in its formative stage and has by no means reached maturity.

Jan 6, 1963