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By R. B. Schluter, M. M. Fine

Development of a process for winning copper from pelletized chalcocite concentrate is underway at the Bureau of Mines, Twin Cities Metallurgy Research Center. The new route from concentrate to metal by which the Bureau seeks to eliminate matte smelting and converting includes a two-stage fluid bed treatment. In the first stage, pelletized concentrate containing 32%Cu and 7% S is first desulfurized to less than 1.0% S in an oxidizing atmosphere. In the second stage, the calcine is metallized by reduction with hydrogen. Thereafter, the reduced product plus 10% CaO is routed to a smelting furnace which separates metallic copper from the gangue. Recovery and Cu content at this point are in the 97-98% range. This product must be refined to remove sulfur and iron so the metal is suitable for making wirebar copper. An important feature of the process is fine concentrate pelletization prior to fluid-bed treatment. This permits a shorter reaction time, a decrease in dusting and easier subsequent processing. In a broad sense, sulfide copper pyrometallurgy is a batch sequence in three separate vessels, i.e., a reverberatory furnace to yield matte copper, a converter to produce blister copper and another reverberatory furnace to produce fire-refined copper. Matte-smelting has remained relatively unchanged since it became a universal practice some 50 to 60 years ago. It is now serving a wide range of smelter feed materials, but many concentrates are not immediately amenable to the process. There are abundant copper resources which lack sufficient sulfur and other elements lo sustain the full chemistry involved in matte-smelting. This necessitates adding sulfur to make the product fit the process, and usually none of the sulfur is recovered. From the standpoint of pollution alone, the development of a smelting technique for low-sulfur concentrates not requiring the addition of sulfur would be a significant gain.

Jan 1, 1970

By Karl S. Kurtenacker

In attempting to find a rapid and economical means for solving many of the subsurface problems that confront the highway engineer, the author for the past two years has utilized a Megger Ground Tester on resistivity surveys in conjunction with highway construction. Electrical surveys in connection with highway work are largely shallow depth surveys, thus differing from most other types of resistivity work. Consequently, the readings are affected by a great many qualifying factors such as the density and moisture content of the media under observation and the amount of weathering and leaching. In most cases the surface layer is decidedly heterogeneous in character, and, because of the great number of side hill cuts, the second layer, which in most cases is rock overlain by some sort of surface soil, silt, or debris, seldom lies in a horizontal position. Shallow strata, lacking homogeneity and not lying in a horizontal position, do not lend themselves readily to accurate theoretical interpretations, therefore the author has used empirical rules to a large extent in interpreting depth soundings. The following empirical rules of interpretation are surprisingly adequate for highway work, since much of the work is in the nature of reconnaissance surveying and the results are construed to be approximations. The writer is careful not to risk interpretation on some special feature of the curve, since such features are usually due to random errors or lack of homogeneity among the subsurface strata. Effect of Surface Medium A resistivity depth sounding taken to a depth of 200 or 300 ft. is not much affected by superficial conditions, but these conditions have a great effect in depth soundings to 25 or 30 ft. In shallow soundings the character of the surface medium has a very marked effect on the entire resistivity graph. Fig. 1 illustrates a very striking example. Graphs A and B are depth soundings taken in approximately the same place. The surface stratum is a clay loam but at the place where graph B was taken

Jan 1, 1934

By Donald W. Frommer

For many years the Bureau of Mines has been con- ducting comprehensive iron ore research programs with the objective of increasing domestic supplies and divising techniques that would enable profitable exploitation of low-grade and complex domestic iron-mineral deposits. Since 1962, much of the Bureau's flotation research at Minneapolis has been concerned with studies on the treatment of low-grade hematitic-goethitic jaspers of the Marquette range, Mich. Ores from Michigan require grinding to substantially minus 400-mesh for liberation that will permit production of quality concentrates. With such fine grinding, diminished flotation effectiveness can be expected because of slime interference. The word "slime" is an ambiguous term. Taggart states "Slimes in an ore pulp are loosely defined as the fine fraction that overflows a desanding separator. . ."

Jan 4, 1964

By H. N. Herrick

The flow characteristics of drilling muds, as described in this paper, and the method given for solving problems relating to the flow of these muds through pipe and accessory equipment, are based on a conception that drilling muds are plastic solids like paints or greases; not liquids. The data presented in this report have been obtained from studies of California muds, chiefly those used in the Kettleman Hills field, by the Producing Department of the Standard Oil Company of California. Although no claim of scientific exactness is made for the formulas and diagrams, since the data upon which they are based are not complete even for California muds, the method has proved to be a convenient means for estimating, closely enough for practical purposes, the pressures required to force muds at various rates through pipe systems in which-they are handled. Certain approximations have been made to simplify the procedures so that they can be used easily in the field. Viscosity and Shearing Strength of Mud For the purpose of this discussion a plastic solid is defined as a material in which no deformation or flow takes place when the material is subjected to shearing forces, until the shearing force reaches a value called the "yield point." With liquids, the smallest force will produce continuous deformation; that is, the yield point of liquids is zero. The difference between true liquids and muds is illustrated in Fig. 1, which shows rates of flow through a small tube under different pressures. The flow rate of the liquids is directly proportional to the pressure and that of the muds is not. The behavior of drilling mud does not conform in every detail with the definition of a plastic solid as given, because mud actually flows slightly at pressures below its yield point. However, for practical purposes the definition describes the condition adequately and has the advantage of simplicity. In order to make mud-flow calculations based on the theory that mud is a plastic solid, it is necessary to know the "yield point" of the mud, which hereinafter is defined by equation 1 under the caption "Viscosity

Jan 1, 1932

By E. I. Larsen, E. F. Swazy, F. R. Hensel

HIGH strength, high-conductivity copper-base alloys have found considerable use in the resistance welding and electrical industry in the form of castings, forgings, or wrought products. There are a number of parts utilized by these industries which would lend themselves to manufacture by powder metallurgical methods provided the required physical and electrical properties are obtainable with such methods. The present paper describes the results of a study of certain copper-base powder metallurgical products susceptible to precipitation hardening. COPPER POWDERS The general types of commercially available copper powders are flake, spherical and electrolytic. Micrographs of these three types are shown in Figs. I, 2 and 3. The difference in particle shape is pronounced and obvious. The type of powder used is determined, or at least indicated, by the final properties desired in the finished article. The type of powder employed during the present investigation was electrolytic powder shown in Fig. 3, and was chosen because of its particular adaptability to the work described in this paper. The screen and chemical analyses of this powder are shown in Table I. In the preparation of compacts of high electrical conductivity, the purity of the copper powder is of importance in addition to other factors, such as density and the state of internal stresses. These variables were studied briefly by pressing a number of compacts to various pressed densities, sintering them for one hour in hydrogen at 975°C. and repressing. The size of the finished compacts was ¼ by ¾ by 8 in. The time interval from the application to the termination of pressure was approximately 20 sec. Some of the compacts were annealed before testing. The results are listed in Figs. 4 to 8, inclusive. [ ] In Fig. 4 the curves of pressed density vs. compacting pressure, and sintered density versus compacting pressure show the typical direct relationship of pressure and density. Compacting pressures exceeding about 30 tons per sq. in. result frequently in expansion during sintering for the type of powder used. Fig 5. indicates that variations in the initial pressed density within the range of about 5 to 6 grams per c. c., affect only slightly the pressure required to obtain a

Jan 1, 1945

By T. D. Yensen

AGING is a term that connotes a slow change in properties under ordinary operating conditions. It can be accelerated by increasing the temperature and by mechanical straining. The magnetic properties of iron and some of its alloys have for many years been known to be subject to such a change. But the cause of the change was not recognized until a few years ago after mechanical age-hardening in non-ferrous alloys of the "duralumin" type had been definitely shown, by means of solid solubility curves, changes in electrical resistance and microanalysis, to be caused by slow precipitation of one or more con-stituents from the solid solution. The similarity between the solid solubility curves of such alloys (Fig. 1) and those for iron-nitrogen (Fig. 2) and iron-carbon alloys (Fig. 3) below the Al transformation point suggested at once that magnetic aging of iron might be caused by a similar process; namely, by the slow precipitation of carbon and nitrogen in the form of Fe4N and Fe3C at ordinary temperatures because of a cooling rate that had been too rapid to permit complete precipitation according to equilibrium conditions. This suggestion has since been amply confirmed, particularly by the comprehensive work of Köster1 on the effect of nitrogen and carbon. Typical curves are shown in Fig. 4 for the relationship between aging temperature and coercive force. Previous to the establishment of the precipitation-hardening theory it was thought that the effect of nonmetallic elements like C, N, 0, etc., on the magnetic properties of iron was greatest when these elements were retained in solid solution, atomically dispersed throughout the interstitial spaces of the iron lattice2.

Jan 1, 1935

By S. J. Shale

Recent changes at Cornwall are highlighted by development of a panel caving method, with slushing drifts, for underground practice as open pit operation nears close. Metallurgy keeps the pace with high recovery from increasing amounts of harder to liberate, higher sulphide content, underground ore.

Jan 7, 1953

By K. J. McGrew, J. W. Murphy

Introduction Maximization of profit consistent with environmental protection is the principal goal of new applications development for any conventional or in situ mining technique. Efficient evaluation of all the parameters that contribute to mining costs and production hinges on proper design and evaluation of testing programs and data. The program discussed uses several field and laboratory procedures to estimate ore deposit characteristics and optimize lixiviant compositions. Ore characteristics and lixiviant compositions are then used in a long path leaching test (stream tube test). Stream tube test data are analyzed by mathematical models with computer assistance to predict such wellfield rate parameters as target metal production, lixiviant consumption, and restoration. When these predicted rates are combined with market values for target metals, capital expenditures, prices of lixiviant chemicals, and other economic variables (labor costs, power rates, and licensing fees), an assessment of the relative feasibility of various proposed mining plans is possible. The flowsheet in Fig. 1 illustrates this process. [ ] Field and Laboratory Procedures In general terms, the procedures followed in the evaluation of an in situ leaching application aim at accomplishing: •rapid leaching and maximum recovery of the target metal in a marketable form, •low consumption of lixiviant chemicals, •unquestionably satisfactory restoration of the mined aquifer, and •minimization of capital and operating costs for the above through development of an optimum mine plan. Keeping these goals in mind, the following minimum test program is generally recommended. Geology •Estimate of ore reserves and their variability. •Average disequilibrium value for uranium deposits. •Ore thickness, depth to ore, water level, degree of confinement, and consolidation. •Characterization of quality and quantity of other ore deposit constituents (e.g. sulfide minerals, ion exchange parameters). Hydrology •Single well pump and injectivity test. •Downhole vertical permeability test to compare flow rates of barren and mineralized formations. •Groundwater quality as it may affect licensing, hydro metallurgy, and restoration. Hydrometallurgy • Flask or autoclave tests for optimization of lixiviant parameters and determination of specific reaction rate constants. • Flask or autoclave tests for assessing amenability of lixiviant solutions with ore, consumption of lixiviant, stability of metal in solution contacting ore, and environmentally important species mobilized. • A long-path leach test for modeling the behavior of the lixiviant solution flowing through a long mineralized streamline (stream tube testing). •Metal recovery tests from lixiviant solutions (ion exchange, electrowinning, etc.). •Lixiviant regeneration tests. •Environmental restoration tests.

Jan 1, 1985

By Eugene Stephenson

CRITICAL analyses of the work expended in producing oil by the utilization of gas energy have appeared in the publications of Shaw,1 Pierce and Lewis,2 and Herold,3 authors who have ably discussed the factors which must be taken into consideration in comparing energy consumed per barrel in various wells which are flowed by means of gas-lift. However, two distinct phases of oil production are concerned with the ratio of gas energy consumed to oil produced. One of these phases is the gas-lift, which utilizes the differential gas pressures for the purpose of flowing oil, whether these pressures be natural reservoir pressures or be induced by artificial compression of gas or air. The other phase has to do with prorating oil production in pools which are operated either as units, or are subject to such restrictions as those imposed at Oklahoma City by the Corporation Commission, or, by similar controlling groups in other fields. An abundance of literature is available relative to the problems of flowing wells by gas-lift, but the first suggestion that the energy of the gas within the oil and gas pool might serve as a basis for proration, appeared in the timely article by McWilliams.4 Much of the. dissatisfaction with proration in certain fields is because some operators feel that besides the hazard to the wells which accompanies the test, the method of allocating production on the basis of the "potential" gage is inequitable and gives some operators a distinct advantage over others.5 The most severe penalty may be exacted from the most progressive operators or those who attempt to produce their oil with a minimum quantity of reservoir gas. If :no difficulties ever

Jan 1, 1931

Organization Place Date 1919 National Drainage Congress St. Louis, Mo. Nov. 11-13 American Mining Congress St. Louis, Mo. Nov. 1.7-21 Canadian Mining Institute Vancouver, B. C. Nov.. 26-28 American Society of Mechanical Engineers:.... New York, N. Y. Dec. 2-5 American Institute of Chemical Engineers Savannah, Ga. Dec. 3-6 Geological Society of America...; Boston, Mass. Dec. 29-31. American Society of Heating and Ventilating 1920 Engineers New York, N. Y. Jan. Mining and Metallurgical Society of America ... New York, N. Y. Jan. 13. American Institute of Min. and Met. Engineers... New York, N. Y. Feb. 16-19 American Ceramic Society Philadelphia, Pa. Feb. 23-26

Jan 11, 1919

By T. Sterry Hunt

THERE are about sixty bodies which chemists call elements ; the simplest forms of matter which they have been able to extract from the rocky crust of our earth, its waters, and its atmosphere. These substances are distributed in very unequal quantities, and in very different manners. As regards the frequency of these elements in nature, neglecting for the present those which constitute air and water, and confining ourselves to the solid matters of the earth's crust, there are a few which are exceedingly abundant, making up nine-tenths, if not ninety-five hundredths, of the rocks so far as known to us. The elements of which silica, alumina, lime, magnesia, potash, and soda are oxides, are very common, and occur almost everywhere. There are others which are much rarer, being found in comparatively small quantities. Many of these rarer elements are, however, of great importance in the economy of nature. Such are the common metals and other substances used in the arts, which occur in nature in quantities relatively very minute, but which have been collected by various agencies, and thus made available for the wants of man. It is chiefly of the well-known metals, iron, copper, silver, and gold, that I propose to speak to-night; but there are two other elements not classed among the metals, which I shall notice for the reason that their history is extremely important, and will, moreover, enable us to comprehend more clearly some points in that of the metals themselves. I speak of phosphorus and iodine. You all know the essential part which the former of these, com- * An address before the Polytechnic Association of the American Institute, during the meeting of the American Institute of Mining Engineers in New York. Printed in this volume by request of many members.

Jan 1, 1873

The University of Illinois, by Prof. H. H. Stock, professor of mining engineering, sent out to its mining students a long letter urging them to attend a Chicago meeting of the Institute. It stated that the University Council authorized the remission of the registration fee for sophomore, junior and senior mining engineers who would attend the meetings and present a written account of the sessions and excursions attended. Young engineers are rarely flushed at the beginning of their careers but if they ever expect to amount to anything at the end of 10-years-they are going to regret that they have not long been a member of the Insti-tute. So that the slogan "Do it now" is snore than particularly appli-cable in their cases and nothing will better indicate to them the scope of the Institute's work and the advantages which they are to get from mem-bership than attendance at one of the big meetings of the Institute and the preparation of a written report on the sessions and excursions attended to be returned to the University.

Jan 11, 1919

By J. Sharshall Grasty, Thomas L. Watson

The users of barite in the United States derive their supply partly from the domestic production and partly from the imports from foreign countries. According to the Mineral Resource division of the U. S. Geological Survey, the domestic production of barite in 1913 was 45,298 short tons, valued at $156,275, or $3.45 a ton, and the imports of crude barite were 35,840 short tons, valued at $61,409, or $1.71 a ton. These figures clearly show a decided advantage in cost of the foreign over the domestic barite to users in the United States. The difference in cost is the only advantage to the consumer of foreign barite, for there are large reserves of the mineral in the United States of good grade. The production of many of the operating mines is capable of decided increase, and it is believed that the operating mines together with the large reserves of undeveloped deposits of barite are entirely adequate to meet the demands of the users in the United States. Deposits of barite are known in California, Idaho, Nevada, and Alaska, but most of them are undeveloped because there is, apparently, no market for the material in that region. The domestic production is derived from Missouri .and the Appalachian States, the greater part being obtained from Missouri. Following the outbreak of war in Europe many users of foreign barite in the United States have been forced to seek their supplies at home. It seems opportune at this time, therefore, that a general review be given of the barite industry in the Appalachian States, one of the two areas from which the domestic supply of the mineral is derived, and that attention be directed to the undeveloped deposits in the region. Briefly, then, this paper reviews the barite industry in the Appalachian States, and describes the occurrence, preparation, and uses of the mineral. General Character Barite, known commercially as barytes or heavy spar, is barium sulphate (Baso4), containing when pure BaO, 65.7 per cent., and S03, 34.3 per cent. The specific gravity is 4.3 to 4.6, and the hardness 2.5

Jan 1, 1915

By Ernest Burchard

A RECONAISSANCE of the chrome and manganese'1ore deposits of Culm was made in the spring of 191s by Albert Burch representative of the U. S. Bureau of Mines and the writer representing the U. S. Geological Survey. The object of the study was to obtain authentic information for use of the: United States Government as to the location, character, size, and availability of the Cuban deposits of the ores of these important steel-alloy metals. The Cuban Government courteously detailed Sr. E. I. Montoulieu, a mining engineer connected with the Treasury Department, to act as escort and associate throughout the work on the Island. Mr. George A. Wright, of Baracoa, Cuba, a mining engineer especially familiar with the chromite deposits of Oriente Province, was a member of the party from Feb. 25 to Mar. 20. It was possible to visit most of, the chrome-ore deposits that seemed to be of promise, but there was not sufficient time to visit all that were brought to our attention, some of which may have merit. Furthermore, no attempt was made to examine the extensive chromiferous iron-ore deposits of the Mayari, Moa, and Cubitas districts, as these deposits cannot be regarded as sources of chromium except indirectly. At the close of the field work the essential data concerning the quantity and quality of ore probably available for shipment during 1918 and 1919, in the event of the continuation of the European war, and of the tonnage of ore in reserve, were furnished to such Government bureaus as were interested, including the Shipping Board and the War Industries Board, and as soon as chemical analyses of the chrome ores could .be obtained, a press bulletin on the subject was published by the Geological Survey. In the present paper the engineering data, and tonnage estimates contained in the unpublished notes of Mr. Burch have been freely used, and their helpfulness is hereby gratefully acknowledged. Many thanks are due Senor Montoulieu and Mr. Wright for their valuable work in the field; to the officials of the Spanish American Iron Co. and of the various other companies; and to individuals holding chromite claims, for courteously facilitating the work of the party. In the study of material for the present paper, chemical analyses have been made by R. C. Wells and petrographic determinations and descriptions were furnished by Miss E. F. Bliss, both of the U. S. Geological Survey.

Jan 9, 1919

By H. S. Price, J. C. Cavendish, R. S. Varga

This paper presents a new technique for solving some of the partial differential equations that are commonly used in simulating reservoir performance. The results of applying this technique to a simple problem show that one obtains accurate pressure values near wells, as well as accurate pressure pdients, which can be explicitly calculated. The method is completely rigorous in that convergence of the discrete numerical solution to the continuous solution for both pressure and pressure gradient is established. High-order, piecewise-polynomial approximations are used near the wells where pressure gradients are steep, while low-order, piecewise-polynomial approximations are used elsewhere to reduce greatly the calculation time. This combination is shown to give a uniformly good approximation to the solution. These approximations, obtained by using a Galerkin process with suitable Hermite subspaces, are shown to be theoretically and numerically superior to the usual approximations obtained from standard finite-difference techniques. Not only are much greater accuracies obtained, but computer times are also greatly reduced. The application of this technique to multiphase flow problems (e.g., single well coning problems) would have considerable practical interest, but such extensions of this technique with full mathematical rigor have not been made as yet. However, the numerical methods presented here are general, and in principle extend to multidimensional, multiphase flow. Moreover, the preliminary results given in this paper are sufficiently encouraging that we feel the effort in attempting these extensions is justified. INTRODUCTION The problem of obtaining accurate pressure distributions and pressure gradients around wells is of considerable importance in the numerical simulation of reservoir performance. The most common approach to solving this problem is to use finite difference techniques (see McCarty and Barfield9 or Peaceman and Rachfordl0). This approach, however, has many disadvantages, the major one being that many grid points are generally necessary for accurately describing the pressure distribution and the pressure gradient around wells. This need for a fine grid results in large computer times and often in prohibitively high costs. Besides investigating the method of finite differences, some authors, such as Welge and weber17 and Roper, Merchant and Duvall,13 have considered a combination of analytical and numerical techniques with some success. These approaches, however, are all nonrigorous and quite often cannot even be applied. In this paper, we present a numerical formulation of high-order accuracy, based on the Galerkin method, for solving this problem. We treat here only the partial differential equation that describes steady-state, single-phase flow. However, the methods presented are general and in principle extend to multidimensional, multiphase flow. Specifically we treat special cases of the problem in two dimensions described by: where G is a rectangle (with sides parallel to the coordinate axis) with boundary ?G, ?/?n denotes the outward normal, and y and B are non-negative constants such that y + B > 0.

Jan 1, 1970

By Jonathan Ludlow, Paul J. Guay

Based on two studies that were funded by the U.S. Department of Energy, the authors provide an overview of the benefits expected from mining deeper webs on United States longwalls. The first study, completed in November 1979, identified the limits and potential gains from taking deeper webs with presently available equipment. The second on-going study discusses the conceptual design and benefits of a future system for taking very deep webs.

Jan 1, 1981

By Thomas T. Read

Readjustment of the industrial world to a peace basis after more than 4 years of war will involve many fundamental and far-reaching changes that cannot as yet be clearly foreseen or definitely provided for. Such problems may be subdivided, in the vocabulary of war, into those involving material and those centering about personnel. Of the two, the latter group is the more difficult and obscure, as the factors involved are less clearly understood and the methods to be followed are not yet tested and standardized. When it is said that the market is weak, stocks large, and demand light, every business man understands clearly what is meant and what course he should adopt to adjust himself, so far as possible, to such conditions. But when it is said that the rapid spread of Bolshevism in Europe is a danger to industrial organization in this country, it is difficult to have any assured sense that all that the statement may mean is clearly understood or that the means to be followed to meet such a situation are definitely known. Since Bolshevism is primarily a mental phenomenon and since the rupture it brings about in industrial organization should be prevented, if possible, it is my purpose to restrict this discussion of the activities of the Committee on Industrial Organization to some of its mental aspects, as the chairmen of the sub-committees, from their special knowledge of their own fields, can best set forth recent progress in the lines with which they are especially concerned. The first requisites of success in industrial organization, as in the biological organism of which it is the social counterpart, are unity of purpose and coordinated activity. Typical good and bad examples of this' are the relative parts that the United States and Russia have played in the great war. These two factors are primarily mental, and it is not difficult to view the mental aspects of all problems of industrial organization as the most important ones. Unless we can attain unity of purpose and coordinated activity in industry, the provision of comfortable homes at reasonable rent, the assurance of steady work at good wages, the elimination of industrial accidents, and provision against want in old age or in case of disability will have brought us no nearer to our real goal.

Jan 1, 1919

By James T. B. Ives

The map exhibited* as an example of my method of construct ing geological strata-maps is essentially an educational appliance. The method, however, is available for the production of maps of comparatively small areas, which, I am confident, will be found of great practical value to mining engineers. Before stating how the method may be so applied I will briefly describe the map exhibited, as the easiest way of making my meaning clear. Almost any region might be taken. This map represents the eastern half of the United States; and the geology is that of the map issued by the Geological Survey, and revised and extended subsequently by Professor Hitchcock for your Institute. I use ten cards, of the colors used in the geological map, each having the geog raphy of the area printed upon it; and I superimpose these in the order in which the colors occur in the index to the map. I next cut away a portion of each card, excepting the lowest, leaving only so much of each as represents the exposure of the formation of that color plus all those which overlie it. When that is done, the whole, looked at from a distance, appears to be an ordinary geological map. Looked at more closely, however, the formations are seen to overlie one another, as in nature. The cards are covered with glass in a frame, which, hinged at the bottom edge, can be let down. The cards are then found to be all hinged in the same manner, and they, too, may be lowered, one after the-other. I am told by teachers of geology of great experience and the highest reputation that by this appliance they will be assisted in im parting to students the first facts and principles of geological sci ence. Having let down the whole series of cards, until that repre senting the Archaean is seen underlying all the rest, the teacher will gradually rebuild it. The Cambrian will thus be laid down upon the Archaean before the eyes of the class, the Silurian upon that,

Jan 1, 1888

Organization Place Date 1919 American Society of Mechanical Engineers... New York, N. Y. Dec. 2-5 American Institute of Chemical Engineers.... Savannah, Ga. Dec. 3-6 Geological Society of America..: Boston, Mass. Dec. 29-31 American Society of Heating and Ventilating 1920 Engineers New York, N. Y. Jan. Mining and Metallurgical Society of America.. New York, N. Y. Jan. 13 American Institute of Min. and Met. Engineers New York, N. Y. Feb. 16-19 American Ceramic Society Philadelphia, Pa. Feb. 23-26 American Electrochemical Society Boston, Mass. Apr. 8-10* *On Apr. 9, a joint meeting will he held with the A. I. E. E.

Jan 12, 1919

Arthur H. Elliott, New York, N. Y.: We have all been very much interested in the results of Dr. Bone's work, which Mr. Ellis has presented to us this evening. The high temperatures attained by this method perhaps afford us an explanation of the temperatures reached in the puddling-furnace with its crude and almost primitive methods of burning fuel, by means of which we have, nevertheless, been able to melt iron in a comparatively short time, and keep it in a molten condition down to a high degree of purity. No doubt many of us have wondered, as I have done, how such a result could be obtained in such a way; and it occurs to me that, perhaps, Dr. Bone has supplied the explanation in disclosing the effect on combustion of burning gas and air after passing through, and in contact with, a porous refractory body. May not the fettling of the puddling-furnace have, in some degree, an effect upon the combustion like the influence of the porous diaphragm employed by Dr. Bone ?

Jan 1, 1913