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Operating Characteristics of Centrifugal Fans and Use of Fan Performance Curve Discussion of paper by. Louis W. HUBER, presented at the New York Meeting, 1926, .and issued, as Pamphlet No. 1542-A, with MINING AND METALLURGY, February, 1926. G. BRIGHT, Pittsburgh, Pa.-Apparently from the pressure curves for a forward-curved-blade fan, in Mr. Huber's paper, practically all ventilation-might be stopped with increased resistance. In order, to discuss the characteristics of a fan we need, some better way to measure the characteristics of a mine. You all know that. the average anemometer is not very-reliable. Sometimes two anemometers, supposed to be recently calibrated, will differ 50 per cent. Either this or some other committee should standardize measuring methods. The characteristic curves of fans, given by Mr. Huber, would indicate that the forward-curved-blade fan would cause trouble in attempting parallel operation, because two machines will not parallel unless they have dropping pressure characteristics. On the other hand, it is indicated that with the backward-curved blade, they could easily be paralleled. But few mines use more than one fan. Mr. Huber said that if the resistance of the mine was considerably more than contemplated, the quantity of air might be such that the efficiency of the backward-curved fan would be seriously affected, dropping say from 70 to 55 or 50 per cent. In such event, could a difference of speed be selected for the fan that would give the quantity desired at a higher efficiency? L. W. HUBER, Pittsburgh, Pa.-The backward-curved-blade fan responds to change in speed the same as any other fan; if' the speed is doubled, the quantity of air is doubled, the pressure is increased four times and the horsepower eight times. One point not mentioned in the paper is that the backward-curved fan is more efficient than the forward-curved or any other type. If the latter were more efficient, it would pay to install that type and keep the resistance of the mine constant, which is hard to do but it can be done with care. But the total mechanical efficiency of a fan with backward-curved blades is from 10 to 20 per cent. higher.

Jan 1, 1927

By Claude P. Heiner

mountain region to M tht Coast points for domestic consumption and for export are shown in Table 11. There is considerable disparity in rates from both Rock Springs, Wyo., and Castle Gate, Utah, to the four coast cities where the slack coal is to be used for purposes other than export. The rate on coal to be exported is the same from either starting point to any of the four coast cities even though there is a difference of as much as 341 miles in the shipping distance. It is interesting to note that the freight rate between Sunnyside, Utah, and Fontana, Calif., on coking coal is $5.05 per ton and that coal up to 8 in. can be moved on this rate if it is suitable for coking. This rate was published late in 1942 on a contemplated annual movement of more than 500,000 tons. There have been decreases in freight rates since 1923 on movements of slack coal from Utah into Seattle and Portland due to pressure on the railroads and to greater. quantity of coal shipped. It is the author,', opinion that a movement of slack coal in excess of 3 million tons of coal per year from Utah to any point in central California would justify a freight rate equal to that puhlished for Fontana, Calif.. or $5.05 per ton. The movement of 3 1/2 million tons of coal per year on the basis of 240 mine working days per year would require that 14,600 tons be handled each mine working day. If it is assumed that shipments could be arranged for a 6-day week, the average railway movement would he 11,200 tons, or approximately 3 trains containing fifty-five 70-ton coal cars per day. Such movements of coal would require railroad equipment represented by the investment amounts stated in Table 12 and entail the services of 250 men. Table 12 ... Railroad Equipment and Investment Required To Move 11,200 Tons of Coal a Day from Utah to California Railroad Equipment Cost 2800. 70-ton coal cara at $6.000 each $16,800.000 32 locomotives at $310.000 each. 9.920.000 Miscellaneous eauiument:.......... .5;000:000 Total........................ $31,720,000 It therefore appears that, under presently known mining methods, the lowest price at which coal could be sold f.0.b. the mine in amounts of 3 1/2 million tons per year for generation of power in central California would be $4.60. It also appears that the lowest freight rate that could be expecled between intermountain points and the central California area would be $5.05 per ton, making a total cost of coal delivered at a plant site of $9.65 per ton. Conelusions The following are the author's conclusions: 1. Coal mines in Utah and in the Kemmerer and Rock Springs districts of Wyoming could increase annual production by 6 1/2 million tons per year. 2. Under present conditions coal could probably be delivered to any steam electric plant in central California at a price not to exceed $9.65 per ton. 3. The use of coal at such a price, while higher than the equivalent present price of fuel oil, is entirely feasible. 4. There are adequate railroad facilities for movements of large quantities of coal from the intermountain region to the Rest Coast. 5. In a national emergency it probably would be extremely difficult, if not impossible, to obtain sufficient oil to meet requirements of the greatly expanded West Coast steam electric generatsing capacity. 6. The intermountain region contains ample coal reserves to supply all conceivable demands for West Coast power generation for a number of generations. 7. Increasing demands of labor threaten to lessen, if not eliminate, savings in cost of coal production through the use of new mining machinery. 8. Continuation of experiments in socialism by the Federal Government through construction of hydroelectric generating plants, particularly those unrelated to land-use reclamation, defies justification. Rates under this concept of a governmental function are subsidized through greater taxation of its people. Private capital is available to construct steam plants, or hydro plants where feasible, and should be permitted to continue in order to preserve the principles of our free enterprise system. DISCUSSION (L. C. McCabe and Robert P. Koenig, presiding) C. C;. BALl*—I was asked to lead off the discussion, but it is not with the thought that I might be able to add anything to the paper. The thoroughness with which it was prepared rather forestalls the asking of many questions. Your treatment, Mr. Heiner, is a very valuable contribution. I do want to suggest—that although you have limited your study to this specific question, with certain geographic limitations, many of the things in your paper apply just as well to the eastern coals. I want to agree 100 pct with your final conclusion concerning government-subsidized construction. Id. C. McCabe*—It is certainly worthwhile to take stock occasionally to see where we are going in problems of this nature. I agree with Mr. Heiner that ultimately the only reliable source of fuel that the West Coast has is coal hut the time factor is the difficult element to evaluate. Just before I came here I discussed this subject with N. B. Hinson, Vice President and Executixe Engineer of the Southern California Edison Company, and Chairman of the West Coast Inter-Power Exchange Committee. He has given much thought to utilities' fuel supply and it was very helpful to me in preparing a discussion of the paper to talk with him beforehand. Stock taking and forecasting of future development are essential to the continuing success of any enterprise. Mr. Heiner has called attention to the unprecedented growth of central and southern California and to the increased demands for fuel and power which have accompanied it. He discusses the increased fuel oil and natural gas requirements and the probable limits on the future use of these fuels and of hydroelectric power. In contrast to the calculable limits of these sources of electric energy, the author points to the availability of enormous reserves of coal in the Rocky Mountain States adjacent to the Pacific Coast which can be utilized for power generation. That there will be increased use of coal for power generation in the area under discussion is generally accepted hut it is in the timetable of such development that there is not complete agreement. In a recent report, Mr. Hinson reviewed the future power outlook for the Pacific southwest area. He pointed out that the use of steam plants in connection with water power plants in this region has made the maximum use of hydroelectric energy possible, and that the correct balance between hydro and steam generating plants produces the most economical overall system. Steam plants in the area which had been installed to protect against deficiency in hydro energy in dry years were used to carry war loads. Fortunately, no dry

Jan 1, 1950

By J. L. Keats

IN THE literature on the elimination of metalloids in basic open-hearth practice, there are a great many heats recorded in which excellent data on changes in slag and metal composition during refining are given, but in almost all of these heats either temperature data or weights and analysis of charge are unrecorded and observations on the physical characteristics of the slag are almost always lacking. With these points in mind, a test heat was made in which as complete as data possible on all the factors that affect the elimination of metalloids were obtained. THE TEST HEAT The test heat was made in a standard 100 ton stationary furnace at the Lackawanna Steel Co., Lackawanna, N. Y. on January 17, 1922. The Charge-Scrap.-The scrap consisted entirely of rail-heat butts, selected from a number of heats made, the week before the test. The average analysis of the scrap was calculated from the analysis of these heats-and from the weight of scrap from each heat. Pig Iron.-Two ladles of pig iron were used in the charge and two samples were taken from each ladle as it was poured into the furnace. These four samples were composited for the average pig-iron sample.

Jan 2, 1926

By E. F. Johnson, V. O. Naumann, D. P. Bossler

A method is presented for calculating individual gas and oil or water and oil relative permeabilities from data obtained during a gas drive or a waterflood experiment performed on a linear porous body. The method has been tested and found both rapid and reliable for normal-sized core samples. INTRODUCTION Individual oil and gas or oil and water relative permeabilities are required for a number of reservoir engineering applications. Chief among these is the evaluation of oil displacement under conditions where gravitational effects are significant, such as a water drive or crestal gas injection in a steeply dipping oil reservoir. Numerous proposed methods of obtaining relative permeability data on reservoir core samples have been too tedious and time consuming for practical use, or have yielded questionable and sometimes inconsistent results. A method has been developed by which the individual relative permeability curves can be calculated from data collected during a displacement test. The method is based on sound theoretical considerations. Using this method, with a properly designed experimental procedure, relative permeability curves can be obtained using core samples of normal size (i.e., 2 to 3 in. in length and 1 to 2 in. in diameter) within a few days after receipt of the core. In a recent publication D. A. Efros1 describes an approach to the calculation of individual relative permeabilities that is based on the same theoretical considerations. We believe the approach described in the present paper is more adaptable to practical application than the method implied by Efros. In addition, comparisons with independently determined relative permeabilities are furnished to substantiate the reliability of the new method. DERIVATION Previously the theory of Buckley and Leverett as extended by Welge2 as been used to calculate the ratio of relative permeabilities. In the derivation which follows, this theory is further extended to permit calculation of the individual relative permeabilities. The theory assumes two conditions which must be achieved before the method is applicable. They are that the flow velocity be high enough to achieve what has been termed stabilized displacement,3 and that the flow velocity is constant at all cross sections of the linear porous body. In stabilized displacement the flowing pressure gradient is high compared with the capillary pressure difference between the flowing phases. The high pressure drop insures that the portion of the core in which capillary effects predominate will be compressed to a negligibly small fraction of the total pore space. The assumption of constant flow velocity at all

By S. S. Shen, M. J. Pool, P. J. Spencer

Heats of solution of silver and copper in dilute Ag-Cu-Sn alloys at 720°K have been determined using a liquid metal-solution calorieter. Values of the se2f-interaction coefficient n AgAghave been calculated at constant copper concentrations and n Cu Cuhas been determined at constant silver contents. The reliability of the experimental data is shown by the very good agreement between nCujAg and ij &$; these interaction coefficients have experimental values of -9100 and - 9590 cal per g-atom, respectively. Certain solution models are shown to be inadequate for prediction of solute interaction coefficients in dilute Ag-Cu-Sn alloys. In a previous publication' the results of a thermody-namic study of dilute Ag-Au-Sn alloys were presented. The present work represents the continuation of a program to investigate dilute alloys of the noble metals with tin and in particular is concerned with solute interactions in the Ag-Cu-Sn system. By determination of the magnitude and sign of the various interaction coefficients in dilute alloys it is possible to gain some understanding of the different types of solute-solute and so lute-solvent bonding changes that occur as the solute concentrations are varied. Hence systematic studies of alloys with similar physical characteristics as regards size, structure, electronegativity, and so forth, of their components can contribute a great deal to present theoretical knowledge of solutions. The recent definition of an enthalpy interaction coefficient, 11, by Lupis and Elliott2 is of particular value in calorimetric studies such as the present one: where j and i are solutes and s is the solvent; Si is the relative partial molar enthalpy of component i and x represents the mole fraction of solute or solvent. Values of ?Hi can be obtained directly by solution calorimetry and data for n are thus easily determined, often with a high degree of accuracy. ?Hi is related to the relative partial molar enthalpy at infinite dilution, ?Hi and to the enthalpy interaction coefficients by the expression: ?Hi?Hi + X;nz+ ... [2] The aim of the present work was to determine the self-interaction coefficients n AgAgand 178: in alloys of different compositions and also to establish values for n Agcg| and ncuAg. Since it is a thermodynamic requirement (resulting from the Maxwell-type relationships which can be applied to partial molar properties) that nAgcu and ncuAg should be equal, a further aim of this study was to demonstrate the agreement between experiment and theory. EXPERIMENTAL A description of the liquid metal-solution calorimeter used in this research has already been published,3 and no further details of its construction and operation will therefore be given here. Copper supplied by the American Smelting and Refining Co. was indicated by them as being 99.999 pct pure, and the silver obtained from A. D. Mackay, Inc., was also quoted as being 99.999 pct pure. A solvent bath consisting of between 70 and 80 g of 99.99 pct pure Sn was used for each series of experimental drops. Its weight was accurately determined and the appropriate amounts of copper or silver were added to give alloys of the desired composition. Approximately 0.00125 g-atom additions were used for determinations of the heat of solution of silver in the bath, while, for copper, specimens consisting of approximately 0.0015 g-atom were used. The heat capacity of the bath was determined at regular intervals during a series of drops using tin or tungsten calibration samples. The heats of solution of silver and copper in pure tin were first determined as a function of their concentration in order to establish the self-interaction coefficients 7AgAg and ncucu Alloys containing a constant 0.01, 0.02, 0.03, and 0.04 mole fraction of copper were then used to study 17:: in alloys of different copper content, while alloys of the same mole fractions of silver were used to determine equivalent data for 178: at constant silver concentrations. The composition of the bath was held at the desired copper or silver concentration by making calculated additions of the appropriate solute throughout the experiment. From the limiting values of ?HAg in the constant copper content alloys it was possible to study ?HAg as a function of xCu and hence to determine 42:. A similar analysis of the re, values permitted calculation of nAgcu. Heat content and heat capacity data from Hultgren et al* were used to calculate heat of solution values from the measured heat effects at the experimental temperature of 720°K. RESULTS AND DISCUSSION Determinations of ?HAg. A preliminary investigation of the heat of solution of silver in pure tin at 720°K was first made in order to establish the value of nAgAg before additions of copper were made and also to compare the value of ?HOAg(l) with that obtained in the previous study of Ag-Au-Sn alloys.' Then the heat of solution of silver in Cu-Sn alloys was investigated as a func-

Jan 1, 1970

By H. A. Stacy

THE ability of galvanized sheet steel to withstand severe bending is of very great importance as relates to all such sheet material which, in service, is not used in the flat condition in which it is purchased. A "bend-test" clause is found in, all specifications for material of this kind. In the attempt to draw up a specification for galvanized sheet steel the subcommittee of the Federal Specifications Board having this work in charge, soon found that there was a surprising lack of published data and apparently very little available from manufacturing sources upon which to sustain or reject the various requirements embodied in the tentative specification which, in turn, had been based largely upon other specifications submitted to the subcommittee for this class of material. Specifications from 25 sources were received; 10 Government specifications, 10 from private users of such material, and five from manufacturers. The main points raised were: (1) The minimum mandrel thickness, expressed in terms of the thickness of the sheet tested, over which sheets with different weights of coating can be bent 180°, without serious damage to the coating; (2) the minimum radius of curvature on the inside of the angle in 90°-bends in such material; (3) effect of double seaming on the coating; (4) uniformity in the thickness of coating over a sheet, particularly as relates to the results of bend tests. In view of the uncertainty existing, it was considered very desirable for the subcommittee to conduct a series of tests in order to secure reliable information.

Jan 10, 1926

By George Otis Smith

A PHILOSOPHER has pointed out that inventive genius, in substituting mechanical power for human brawn, leaves' man the intellectual factor in the industrial life. "Almost human" is the description sometimes applied to the automatic machine, yet the true characteristic of the perfect machine is its unquestioning obedience. "Its not to reason why." The human operator, not the mechanism of gears and levers, has freedom of choice: he wills; the machine obeys: There map be a grinding monotony, a tiring rhythm, that passes from machine to man, but the responsibility resides in the man. In no proper sense call the machine worker be called the slave: whether he guides an electric shovel or tends a group of automatic 1athes.in the machine shop.

Jan 1, 1930

By J. J. Stokes

Literature on the electrolysis of aluminum from cryolite melts and on the structure of these melts is surveyed critically. Data on density, freezing point, and other properties are reviewed. Theories of the electrolysis are examined in the light of these data. Two theories are presented which account equally well for the observations. ALTHOUGH the production of aluminum is a large-scale industrial process, consuming approximately 3 pet of all of the electric current generated in this country, the mechanism of the Hall Process remains a 70-year-old mystery. It is a remarkable fact that the aluminum industry, which was established largely through research and owes much of its growth to research, still employs as its basic process the one developed by Charles Martin Hall while he was still a young man working in a woodshed. There are, of course, modifications in detail and a tremendous expansion of the size of the units used, but basically the process employs carbon anodes and a carbon-lined iron vessel as a cathode for the electrolysis of alumina dissolved in molten salt. Of the almost infinite variety of salts available, the relatively minor Greenland mineral, cryolite, 3NaF.A1F3, is still the only one which gives good performance in the electrolysis. In the early days, the process was thought of as a simple one. The dissolved alumina dissociated and, during the electrolysis, the aluminum was carried to the cathode where it was discharged and collected in a pool of metal. The oxygen was carried to the carbon anode where it reacted to form primarily carbon dioxide together with some carbon monoxide. About the only virtue that can be claimed for this hypothesis is that of simplicity. The actual mechanisms must be tremendously more complex. This paper is devoted to a rather narrow part of the whole subject, namely, what ions are present in the bath, and by what mechanism the current is carried. The complexity of the literature on this system is demonstrated in Table I, which shows the ions postulated as being present during the process. This system is not easy to investigate. Cryolite melts at about 1000°C, so that all the investigations are at relatively high temperatures. Molten cryolite fumes in air, particularly if excess aluminum fluoride is present. The cryolite changes composition on heating at 1000°C, principally by reaction with moisture in the air, but apparently also by reaction with oxygen. Cryolite reacts with most of the customary materials of construction, and those that are not attacked by cryolite seem inevitably to react with molten aluminum. Graphite is the only common material that is inert to the electrolytic bath. Pure cryolite can be held in platinum. There is hope that some of the newer refractories will stand up in bath, and their development for this purpose would be a major advance in the field. The techniques to be discussed, then, are not the most advanced ones. Rather, they are examples of old standardized methods applied under difficult conditions. The principal methods that shed real light on the mechanism are density, electrical conductivity, freezing-point lowering, transport number, viscosity measurements, and reactivity of bath with carbon dioxide. The first measurement to be discussed is density. This procedure is relatively straightforward. A hollow platinum bob is suspended by fine platinum wire from an analytical balance into the melt being investigated. Density1-4 of the system sodium fluoride-aluminum fluoride is shown in Fig. 1. There is a maximum in the density near the cryolite composition, but actually the maximum is on the NaF-rich side of cryolite, close to the composition NaF - Na3AlF8. Density measurements are also useful in giving a clue to the nature of cryolite-alumina melts.1, 4 On the first addition of alumina, density decreases, Fig. 2, although the density of alumina, either solid or liquid, is higher than that of cryolite. These density results indicate that the systems are not simple. A great deal of effort has been spent in measuring the electrical conductivity of molten cryolite and of cryolite with various additives. Conductivity measurements are quite easy for fused salts that can be measured in a dip cell, but no successful dip cell has been made available yet for cryolite. Recourse is had

Jan 1, 1959

By F. F. Sharpless

ON Saturday evening, Sept. 9, a small party of Institute members, their wives and friends, left New York to attend the Fall Meeting of the Institute at San Francisco. In this party there were: President and Mrs. Arthur S. Dwight; Mr. and Mrs. George D. Barron; Mr. and Mrs. H. J. Stehli; N. S. Spencer and Miss Spencer; the Secretary and Mrs. F. F. Sharpless. They were joined at Chicago by E. F. Eurich, and by Mr. and Mrs. R. L. Baldwin and daughter. Our party was met at Chicago by Mr. and Mrs. L. V. Rice, Mr. and Mrs. A. D. Terrell and W. F. Boericke, who constituted themselves an impromptu entertainment committee and proceeded to carry out a delightful little program. We were taken to the Lake Shore drive, where a stiff wind off the lake refreshed us after a sultry day on the train, and on our return to the city saw Chicago illuminated with all its brilliance of electricity. We were entertained at dinner at the Drake Hotel. In spite of being two hours late getting into Omaha, we were right on the dot at Denver on Tuesday morn-ing. Horace F. Lunt came to the hotel soon after breakfast, and told us that a trip to the mountains had been planned. Having learned the number in the party, he began to gather up his automobiles for a 10 o'clock start.

Jan 10, 1922

By W. E. STOKES

SOME extension of flying service to the mining industry occurred in 1938, particularly in Canada, where freighting activity radiated from Edmonton into the new northern mining districts. Again the airplane demonstrated its usefulness in getting new equipment rapidly into the field and in decreasing shutdown time while waiting for repairs. An 18-ton Caterpillar tractor with shovel attachment was disassembled, brought in by plane, and placed in operation at Berens River, Ont., within seven days after its de- livery at Winnipeg. At Central Patricia a mill breakdown required the replacement of a full mill head and trunnion with ball bearings, weighing 2700 lb. The Canadian Airways Junkers, termed the "flying boxcar," was called in from Yellowknife, 1300 mi. away, and the new installation was completed three days later.

Jan 1, 1939

By AIME AIME

THOUGH the Annual Meeting of the Institute-officially numbered 158 on the records was delayed a bit at the start by low steam pressure on the locomotives bringing members to New York, the crowd that finally arrived more than lived up to expectations, and the technical program had few difficulties because of absent authors or lack of competent discussers. The transportation difficulties were occasioned by the fact that Monday, Feb. 15, was the third coldest day in the 72 year history of the New York Weather Bureau, the official temperature being 8 below zero. The New York Central's premier train, the 20th Century, due at 9:30 a.m., arrived about 6:30 p.m., and the Commodore, another crack train from Chicago, was about equally late.

Jan 1, 1943

By James E. York

THE honor so fairly earned and so incompletely and tardily paid to Henry Cort, the inventor of the puddling-furnace and the, rolling-mill, has been fully set forth by Mr. Charles H. Morgan,1 and needs no further emphasis here. In view of the importance of the rolling-mill in the treatment of iron and steel, the paucity of information concerning it is surprising. With the exception of a hook, written about 35 years ago, by Peter Bitter von Tunner, an Honorary Member of this Institute, and of desultory articles on simple sections, which have appeared in technical journals, I know of no pub¬lication attempting to treat this subject, although volumes have been written on the scientific theory and technical manipulations involved in other branches of the iron- and steel-industry. This strange anomaly may be due to the fact that roll-turning cannot be called a scientific business. It does not ordinarily come within the range of an educated engineer; yet it cannot be performed by an ordinary mechanic. It demands some of the qualifications of an engineer, in designing, and those of a mechanic, in execution. The men who have followed this trade have controlled the training of their successors. In many cases the technical knowledge required bas been handed down from father to son, and there has been a motive of private interest to prevent its public dissemination. Moreover, the statement of the various principles involved in the process would require, besides manual experience, a degree of scientific knowledge which roll-turners do not usually possess; and, finally, any book on the subject, in order to possess real, practical value, would have to be so fully illustrated as to make it very costly to publish. Regarding my own experience, I may say that I served a six-

May 1, 1906

By J. N. Sicking, F. H. Brinkman

A new method for obtaining equilibrium vaporization ratios (K-values) for reservoir fluids has been developed and tested. By application of the method, complex experimental measurements of liquid and vapor phase compositions are eliminated. This simplified technique reduces the cost of experimental equilibrium-ratio data for reservoir studies of condensates and volatile crude-oil systems. The method is designed for systems of constant composition and, therefore, is best suited for depletion studies where compositional changes at high pressures are minor. The basic data required, in addition to the composition of the initial reservoir fluid, are the relative vapor-liquid volumes and densities at reservoir temperature and variom reservoir pressures. Tests demonstrated that the method predicts equilibrium ratios accurately for condensates. A single test on a crude oil was not conclusive; further testing will be necessary before the accuracy of the method can be determined for crude-oil systems. In addition to determining equilibrium ratios, the calculation method provides information on the physical properties of the "plus" component in the vapor and liquid phases. The "plus" component is that mixture of components heavier than the least volatile fraction analyzed. This information is useful in studies of both natural depletion and cycling operations for condensate reservoirs where the heptanes-plus component in the gas phase is produced from the reservoir. INTRODUCTION As more volatile oil and condensate reservoirs are found, the use of phase behavior techniques to predict their performance is increasing in importance. These techniques have long been used for condensate fields and have more recently been applied to crude-oil fields containing oils of medium-to-high volatility. In these phase behavior methods, equilibrium ratios (K-values) are used to predict compositional changes in the reservoir fluids—thereby accounting for the recoverable oil that exists in the gas phase. The reliability of the predictions depends to a large extent on the equilibrium ratios used. These values must be obtained for each component for the entire pressure range being investigated. Unfortunately, because of the complex nature of hydrocarbon mixtures, accurate K-values are hard to obtain. The equilibrium ratios for a particular component will vary not only with the temperature and pressure, but also with over-all composition of the system. The importance of composition is quite critical at elevated pressures, but becomes negligible at pressures below about 300 psia. Therefore, because most phase behavior problems involve the high-pressure region, each fluid system becomes a special case. Experimental programs to determine characteristic K-values are quite difficult and time-consuming. Thus, it is often necessary to resort to approximations of the K-value data. Charts giving K-values for various mixtures and classes of mixtures are available in the literature. However, there are two major difficulties in using them: (1) the K-values of the "plus" component (that mixture of components heavier than the last one analyzed) must be obtained by extrapolation from the K-values of the other components; and (2) the K-values obtained must finally be adjusted by trial and error to agree with observed volumetric data. To eliminate these difficulties, a new method of determining equilibrium ratios was developed. Briefly, after the composition of the system as a whole has been analyzed, the method uses empirical correlations and the gross fluid properties of the system (relative vapor-liquid volumes and densities) to calculate K-values. Because the calculative procedure is long, it is best solved on a digital computer. About one hour of machine time on an IBM 650 computer is required to develop a K-chart for the fluid being examined. DEVELOPMENT OF THE METHOD OF OBTAINING K-VALUES Equilibrium ratios are defined as the ratio of the mole fraction of a component in the vapor phase to its mole fraction in the liquid phase. This statement is expressed in Eq. 1. A typical plot of equilibrium ratios for a particular system is shown in Fig. 1. It should be noted that, at pressures near the saturation pressure, the K-values appear to converge to a common point. This apparent convergence point is called the convergence pressure and is a characteristic of the system involved. Various empirical correlations of K-values have been noted. It has been observed that an isothermal plot of

By Robert Gilman Brown

The original power-plant of the Standard Company has been described* by Mr. T. H. Leggett, late president and manager of the company; but since the presentation of his paper considerable additions have been made, which will be found interesting because of the engineering features involved and of the attainment of a high degree of flexibility with the inflexible, two-wire, alternating system of electrical transmission. Although these additions have been completed during the last year, they constitute, to a large extent, only the carrying out of plans that belonged to the original conception of the installation. The regular operation of the water-power through the winter proved very difficult; there was a considerable length of ditch to be kept open, and, as the stream is small and any freezing night may stop the whole flow of water, there was the .additional trouble of having no reserve to draw upon. The rule for the winter is, that after a night of hard frost water begins to move in the canon before noon on all but the coldest days. To obviate the nuisance of the anchor-ice, and to make available all of the water, a dam of sufficient height to impound several days' run of water has been built across the canon, 3875 feet above the power-house, and provided with pressurepipe well below the surface. In place of the 1571 feet of pipeline from penstock to power-house, there has been substituted a line 3875 feet long to bring water direct from the dam. The dam is of logs, cribbed up in squares of about 12 feet, ballasted with earth and rock and sheathed on the water-face with 3-inch plank.

Jan 1, 1897

All the TECHNICAL PUBLICATIONS and CONTRIBUTIONS published in 1940 are available at Institute headquarters, unless otherwise noted. They are also on file in many public, university and technical libraries and, when so indicated in the list, may be found in the TRANSACTIONS. TECHNICAL PUBLICATIONS in Classes A-Metal Mining, B-Milling and Concen-tration, H-Industrial Minerals, and I-Mining Geology are distributed in MINING TECHNOLOGY, which is issued every other month. Technical Publications in Classes C-Iron and Steel Division, D-Nonferrous Metallurgy and E-Institute of Metals Division are distributed in METALS TECHNOLOGY, which is issued twice quarterly. TECHNICAL PUBLICATIONS in Class G-Petroleum Division are distributed in PETRO-LEUM TECHNOLOGY, which was issued quarterly in 1940 but will be issued every other month in 1941. TECHNICAL PUBLICATIONS in Classes F-Coal Division, J-Mineral Industry Education Division, K-Mining Administration, and L-Geophysical Methods of Exploration are issued as separate pamphlets. An Institute member is entitled to one copy of any TECHNICAL PUBLICATION or CONTRIBUTION. Copies of TECHNICAL PUBLICATIONS listed have been mailed to members of the Institute accord-ing to their registration by classes. CONTRIBUTIONS and other TECHNICAL PUBLICA-TIONS will be sent upon request. A member may purchase an additional copy of a TECHNICAL PUBLICATION or a CONTRIBUTION at one cent a page; minimum charge, 25¢. Nonmembers may purchase any CONTRIBUTION or a TECHNICAL PUBLICATION of the F, J, K, or L classes at the same rate, but the nonmember price per copy for METALS TECHNOLOGY, MINING TECHNOLOGY or PETROLEUM TECHNOLOGY is $1.25 domestic, $1.35 foreign countries. TECHNICAL PUBLICATIONS (separate pamphlet form), $2 per annum domestic, $2.50 foreign. METALS TECHNOLOGY, $7 per annum domestic, $7.80 foreign (Iron and Steel Division and Institute of Metals Division ferrous and nonferrous papers). MINING TECHNOLOGY, $6 per annum domestic, $6.60 foreign (metal mining, milling and concentration, Industrial Minerals Divi-sion, and mining geology papers.) PETROLEUM TECHNOLOGY, $6 per annum domestic, $6.60 foreign. Bound volumes have been mailed to members that have requested them, and MINING and METALLURGY is mailed each month. A member is entitled to one volume a year on his membership and he may purchase for $2.50 one copy of a volume not already received; additional copies of the same volume, $5. Nonmembers may pur-chase the volumes listed, at $5 each, plus 60 cents for Canadian or foreign postage. Extra single copies of MINING AND METALLURGY, 25¢ current issue, back numbers 50¢ each to members; to nonmembers 506 current issue and $1 each, back issues. Subscription price to nonmembers and to members for extra copies, $3 per annum domestic, $4.00 foreign.

Jan 1, 1940

By Raymond E. Zimmerman

The Swirl Cyclone developed in Japan, although based upon the same principles as the standard cyclones for heavy-media or water-only cyclones for cleaning coal, is novel in that it is invested with the apex on top, discharging rejects at the top, and clean coal at the bottom. It also uses a variable air vent tube for controlling the vortex. Tests conducted indicate that its efficiency is not only as sharp as standard cyclones but it also performs using a much coarser grain magnetite, promising higher magnetite recovery. The author describes the results of tests conducted in Japan on a very difficult coal.

Jan 1, 1979

By Earl Oliver

IN times like these, the A. I. M. E. and similar societies have their greatest usefulness. . . . Individuals and companies acting alone in the development of public opinion are merely voices crying in the wilderness. United and organized they make a great force that can and does influence public action. . . . What part, if any, then, shall the A. I. M. E. take in these great stabilization processes of civilization? Shall it help to give direction and force to scientific knowledge which comes within its field of activity or shall it merely develop more of it? . . . Is it the A. I. M. E.'s function to help bring system, order and direction out of this situation so that the world can again have forward economic movement, or should it rest on its oars until other agenciess develop that public understanding and direction so necessary for economic progress? As we understand the functions of the A. I. M. E. Petro¬leum Division, they are to discover and promote knowl¬edge for the benefit of society on the mining of oil and gas. To the individual member of the Petroleum Division, there are certain advantages of social and professional contacts, but the collective purpose is that described. And the individual is benefited by membership only as the Division measures up to the purposes of its existence. Consequently, the welfare of this Division and that of its members depends on the extent to which it keeps pace with the needs of society on matters relating to the mining of oil and gas.

Jan 1, 1932

By AIME AIME

THE MODEL LAW previously referred to', in these columns several times, prepared by Engineering Council, to be o ered in any state where legislation is introduced for licensing engineers, is given in abstract below. , Mining engineers throughout the country should watch legislation of this sort and see that the draft prepared by Engineering Council is in the hands of any state legislative committee which proposes to frame a licensing law. So far as this office is informed, the mining engineers are a unit against licensing, but if we must be licensed the most innocuous law that has been submitted is the draft prepared by Engineering Council. ABSTRACT OF MODEL LAW -FOR REGISTRATION OF PROFESSIONAL ENGINEERS, ARCHITECTS, AND LAND SURVEYORS

Jan 1, 1920

By H. L. Barr

THE following report covers the history of the development of the mine, present equipment, methods and costs of mining and milling. In addition, a description of the ore deposit is given with emphasis on the origin of the fractures, mode and types of ore occurrence, and mechanics of granite emplacement. An endeavor has been made to present a complete and accurate statement of the San Mauricio mine, the highest grade gold mine in the Philippine Islands. Credit is gratefully acknowledged to the mine staff for descriptions and details regarding their particular field of work. All analyses were made by Mr. T. A. DeVore, head chemist, San Mauricio Mining Co. Messrs. Edward Wisser, J. E. Fyfe, A. F. Skerl and W. B. Meek, geol-ogists, have contributed geologic information and ideas, for which thanks are extended. The Executive Committee of Marsman and Co., Inc., Managers of the Company, has kindly given permission for publication. Mr. J. B. Stapler, Division Manager, Marsman and Co., has had the courtesy to read the manuscript and to give critical and helpful suggestions.

Jan 1, 1940

By Thomas T. Read

THE benefits derived from stabilization of industry that might possibly be attained through some scheme of centralized economic planning have been much discussed of recent months, and opinions on the subject range from those who believe that some agency like the War Industries Board would be practicable to create and wholly beneficial in effects, to those who are equally convinced that none of the suggestions so far advanced are at all practicable, or likely to be productive of more of good than of evil. The discussion has been on the general topic, but-many of those who have written or spoken on it have introduced economic problems of the pinera1 industry; for example, Newton D. Baker, who referred to the coal industry in his address on economic planning at the Williamstown Institute of Politics on July 31, and then went on to say, "Industrial progress is made by the development of new things, but new things upset the equilibrium of any plan. Who could have planned the industrial effects of the development of the railroads, or the economic changes which you have seen attend the development of the internal combustion engine. Obviously, unless we are prepared to put world economics in a strait-jacket and, like the encyclopedists, write its full history on the theory that further progress is impossible, no such plan could be made for nations which are forging ahead as is entirely rational for nations which are still catching up."

Jan 1, 1931