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By E. A. Gulbransen, W. S. Wysong

THE behavior of molybdenum and its surface oxides in oxidizing and reducing gas atmospheres and in high vacua at elevated temperatures is a question of scientific and technical importance The use of molybdenum as a metal or as an important component in alloys in oxidizing atmospheres at elevated temperatures has been limited because of the unprotective nature of its oxide film and the volatility of this oxide at moderate temperatures. This communication will present results of a vacuum microbalance study 1,2 of the following problems. (11) the oxidation kinetics in the temperature range of 250° to 450°C; (2) the reduction with pure hydrogen of thin oxide films formed on molybdenum; (3) the volatility of the thin oxide films, and (4) the vacuum oxidation of molybdenum at high temperatures. Molybdenum is an interesting metal to study for the following reasons: (I) although the oxide-to-metal-volume ratio is greater than one, the metal is not considered protective; (2) the metal oxidizes readily at temperatures of 250°C and higher; (3) the oxides of the metal are reduced at temperatures as low as 500°C by pure hydrogen; (4) the oxide MoO3 melts at 795°C; and (5) the oxides of molybdenum are volatile at moderate temperatures. The following variables are studied in the oxidation kinetics. time, temperature, pressure, surface preparation, surface area, concentration of inert gas in the lattice, cycling procedures in temperature, vacuum effect and high temperature vacuum oxidation The general interpretation of many of these factors has been previously discussed. LITERATURE The oxidation of molybdenum has not been studied critically. Although" many studies have probably been made on the kinetics of the oxidation process, none has been reported in the literature available to us. The crystal structures found in the oxidation of molybdenum have been studied by Hickman and Culbransen 4 Their results showed that MoO2 is the oxide which is stable in contact with the metallic subgtrate throughout the temperature range 300 to 700°C. As the film thickens in the low temperature range, MoO3 becomes predominant on the surface. Above 400°C, Mo03 is no longer observed, Mo02 being the only oxide found. Hagg and Magneli5 have shown from an X ray study that the a-phase, orthorhombic MoO3 is stable up to 1050°C. Two other phases, ß and ß', with compositions close to Mo02 90 are also obtained The formula for the ß phase is not given but that of the ß' phase is defined as Mo9026. The ß' phase is found to be built upon a monoclinic unit cell. A -?-phase is isolated from a preparation M00275 heated for 17 hrs at 670°C. This phase is

Jan 1, 1947

By M. D. Hassiallis

The claim is made in a number of patents1'2'3'4 that some compounds of the class known as aryl sulphides have collector properties. One of these patents generalizes the claim to include all aryl sulphides, whose generic formula is R-S2-R' (where x = 1,2, . . . ), with the restriction that if the aromatic radicals R, R' contain substituent groups these groups may not contain nitrogen or oxygen. Moses, Hess, and Perkins cite as evidence for their claims the results of flotation tests on Anaconda and Miami copper ores using diphenyl sulphide, ditolyl disulphide and dinapthyl disul-phide as collectors. The use of alkyl sulphides as collectors has also been reported5 with the conclusion that the alkyl sulphides are better collectors than the corresponding aryl sulphides. The experimental work cited appears to confirm this contention. In order to test these claims with respect to diphenyl sulphide, a sample, purchased from the Eastman Kodak Co., was tested against Anaconda ore. The procedure followed. was that of Moses, Hess, and Perkins. A sample of ore weighing 500 • grams was placed in a laboratory ball mill. To this was added 220 grams of water, 0.06 grams of commercial diphenyl sulphide (1/4 lb. per ton of ore), and 0.8 grams of lime (3 lb. per ton of ore). The material was ground until 93 per cent passed a 65-mesh screen. This pulp was diluted to 16 per cent solids. A sample of the diluted pulp was placed in a Minerals Separation type of laboratory flotation cell. After a a-min. agitation period, pine oil was added and the froth collected for a period of 15 min. This test recovered 68 per cent of the copper, with a ratio of concentration of 6.8:I. The tailing assay was 0.3 per cent Cu. Moses, Hess and Perkins attained a recovery of 75 per cent, with a ratio concentration of I2:I. Although these results do not compare too well with those of Moses, Hess and Perkins, subsequent tests showed an improvement, as judged by vanning of the tails. It is concluded, therefore, that the patent results are confirmed. Contact-angle Tests In order to study the response of the various minerals, found in Anaconda ore, to commercial diphenyl sulphide, some contact-angle tests were made. Polished particles of bornite, chalcodte, chalco-pyrite, pyrite and quartz were conditioned for 15 min. in a suspension of diphenyl sulphide in water. The concentration of this suspension was 0.284 grams per liter, this being the concentration of this reagent in the ball mill. The conditioned particles were rinsed with water (not rubbed with filter paper or boiled linen) and then tested against an air bubble in the bubble machine, with the following results: born-

Jan 1, 1943

By M. D. Hassiallis

The claim is made in a number of patents1'2'3'4 that some compounds of the class known as aryl sulphides have collector properties. One of these patents generalizes the claim to include all aryl sulphides, whose generic formula is R-S2-R' (where x = 1,2, . . . ), with the restriction that if the aromatic radicals R, R' contain substituent groups these groups may not contain nitrogen or oxygen. Moses, Hess, and Perkins cite as evidence for their claims the results of flotation tests on Anaconda and Miami copper ores using diphenyl sulphide, ditolyl disulphide and dinapthyl disul-phide as collectors. The use of alkyl sulphides as collectors has also been reported5 with the conclusion that the alkyl sulphides are better collectors than the corresponding aryl sulphides. The experimental work cited appears to confirm this contention. In order to test these claims with respect to diphenyl sulphide, a sample, purchased from the Eastman Kodak Co., was tested against Anaconda ore. The procedure followed. was that of Moses, Hess, and Perkins. A sample of ore weighing 500 • grams was placed in a laboratory ball mill. To this was added 220 grams of water, 0.06 grams of commercial diphenyl sulphide (1/4 lb. per ton of ore), and 0.8 grams of lime (3 lb. per ton of ore). The material was ground until 93 per cent passed a 65-mesh screen. This pulp was diluted to 16 per cent solids. A sample of the diluted pulp was placed in a Minerals Separation type of laboratory flotation cell. After a a-min. agitation period, pine oil was added and the froth collected for a period of 15 min. This test recovered 68 per cent of the copper, with a ratio of concentration of 6.8:I. The tailing assay was 0.3 per cent Cu. Moses, Hess and Perkins attained a recovery of 75 per cent, with a ratio concentration of I2:I. Although these results do not compare too well with those of Moses, Hess and Perkins, subsequent tests showed an improvement, as judged by vanning of the tails. It is concluded, therefore, that the patent results are confirmed. Contact-angle Tests In order to study the response of the various minerals, found in Anaconda ore, to commercial diphenyl sulphide, some contact-angle tests were made. Polished particles of bornite, chalcodte, chalco-pyrite, pyrite and quartz were conditioned for 15 min. in a suspension of diphenyl sulphide in water. The concentration of this suspension was 0.284 grams per liter, this being the concentration of this reagent in the ball mill. The conditioned particles were rinsed with water (not rubbed with filter paper or boiled linen) and then tested against an air bubble in the bubble machine, with the following results: born-

Jan 1, 1943

By Robert W. Thompson, Darry A. Ferguson

In August, 1977 the United States Congress passed Public Law 95-87 which has been commonly referred to as the Surface Mining Control and Reclamation Act (or SMCRA). This title is somewhat misleading in that the act creates as many regulatory requirements for underground coal mines as for surface coal mines. How- ever, this paper will concentrate on the effects of SMCRA on designs and stability for various activities of surface coal mines, specifically those concerning "Disposal of Excess Spoil". In the past, the objective of most laws and regulations applicable to the mining industry has been to achieve goals of safety or environmental concerns for all types of mining. However, SMCRA is unique in that it sought to regulate-all-activities of coal mining from initial data gathering, exploration, mine design and facilities design to reclamation activities and design. More specific to the stability of the activities of surface coal mining, special criteria for design and construction performance standards have been promulgated for the construction and maintenance of roads, dams and embankments, coal processing waste, ex- cess spoil piles, backfilled reclamation and pit slides. The criteria for design for the previously mentioned facilities has been enumerated by regulations and in many ways restrict the use of site specific design parameters. The restrictions imposed by regulations significantly inhibit the engineer's ability to develop the best practical and economical design and in some cases may re-

Jan 1, 1983

Experiments on the Rate of Heat Transfer from a Hot Gas' to a Cooler Metallic Surface Members of the American Institute of Mining Engineers will be much interested in the subject of teat transfer from a hot gas to a cooler metallic surface, and although the book on this subject recently published by the Babcock & Wilcox Co., of New York, deals primarily with boilers, it contains a great deal of information which metallurgical engineers will find of great value. The book starts out with an introduction giving some of the current theories regarding this subject; it then describes in detail the experimental apparatus used, and the methods of conducting the experiment's and recording the data. Then follow some account of the determination of radiation losses in jackets and cooler; measurement of metal temperatures; detection and correction of errors; etc., concluding with a discussion of the results and derivation of corrective formula for heat absorption; heat pressure rate and specific heat of gas.

Jan 5, 1916

By Zay Jeffries

Discussion of the paper of ZAY JEFFRIES, A. H. KLINE and E. B. ZIMMER, presented at the New York meeting, February, 1916, and printed in Bulletin No. 108, December, 1915, pp. 2359 to 2369. ZAY JEFFRIES, Cleveland, Ohio.-The original portion of this paper represents a laboratory method for determining grain size in metals. It was developed not so much to find a quick method as it was to facilitate certain work which I was carrying on a couple of years ago. I had a great many determinations to make and the planimeter method was very slow, as was the Heyn method, and both of them were laborious, so I tried to shorten the time of the determinations. Since preparing the present paper, Dr. T. M. Focke, Professor of Mathematics at Case School of Applied Science has called my attention to the fact that both the Heyn and Intercept methods are mathematically

Jan 5, 1916

THERE are two general classes of problems in connection with electric furnaces. First, those relating to the best utilization of the electrical power inside the furnace; second, those connected with the bringing of the electrical power to the point where it is to be utilized. Referring particularly to the latter class of problems, many calculations have been made, covering a wide variety of furnaces, to check the electrical capacity and power factor found from test. The following analysis, made for the purpose of determining the maximum capacity and approximate performance of a new furnace, to operate at 160 volts on a 60-cycle circuit, may be of interest. The first characteristic necessary to determine is the inductance, since this is the factor that limits the amount of power which can be put into the furnace. Inductance is calculated from the dimensions of the furnace, according to formulas of the U. S. Bureau of Standards,1 as

Jan 10, 1918

By J. E. Castle

THE title of this article is descriptive, but not complete, for psychological evaluation is almost as important as rigid economic evaluation. This refers to those human traits that cause people to be too optimistic about the projects they are sponsoring, to overlook obvious weaknesses, to base decisions on incomplete and inaccurate data, and to gloss over embarrassing problems. Investment of capital in a new industrial mineral project is warranted only after rigorous economic analyses based on unquestionable facts. A plunge into production cannot be justified solely because these minerals have been deposited in the ground and are therefore free. There are no specially favorable economic laws that make the business of industrial minerals more attractive than any other. The factors of supply and demand, marketing, technological changes, taxes, competition, and fluctuating prices apply as much to industrial minerals as to other business enterprises. What is more, industrial minerals are subject to the higher risks that all mining enterprises face.

Jan 6, 1958

By Guy R. Johnson

Like many other similar plants the ore-washer of the Longdale Iron Company has been a growth of years. In its principal features there is probably nothing new, as the type is that of the well-known " log-washer." Some of its minor details may, however, be of interest to those members who have to deal with the washing of large quantities of brown iron-ores, the principal gangue of which is clay. * Until 1883, the ore at Longdale, being of unusual purity, needed no washing, and was charged to the furnaces as it came from the mines—both lump and fine—the only attempt at cleaning being the' picking over a screen of 1½-inch iron bars, 3½ inches from center to center, set in the top of the bins through which the cars for the furnaces were loaded." In 1883 it was no longer possible to win the ore by open cuts, and regular underground work became necessary. It was very

Jan 1, 1895

By Guang Ping Cui

In this paper the imminent relationship between rock burst and its phenomenon with normal rock pressure and its appearance, as well as the factors of one changing into another have been analyzed. Based on this, the necessary and sufficient appearing factors of rock bursts have been put forward, and the term ''burst pressure" has been defined. According to the statistics data of tremendous rock bursts which appear in collieries in Hunan Province, the features of high frequency, great strength and shallow depth of the beginning burst have been found. There are some special structures in the coal seams, which are closely related with the burst phenomenon. A hypothesis of "star structure" has been suggested for the appearing mechanism of bursts. Inside and around this star structure the distribution rule of burst pressure and rock strength has been researched depending upon the theory of the limited stress field. A new description of the appearing causes of bursts has been raised.

Jan 1, 1984

By H. E. Sadler, B. Silliman

INTRODUCTORY NOTE. THE research here recorded was undertaken early in the present year, and has been prosecuted steadily for about eight months. While the work has been under my constant supervision and advice, the labor has all been performed by Mr. Sadler, to whom is chiefly due the development of the successive steps which have led to the final result. The process is better than I dared to hope, and we are able to place at the command of chemists and engineers interested in the matter an apparatus of continuous and uninterrupted action, and methods of analysis by which the daily averages of the two variable and inconstant factors of illuminating gas, ammonia and sulphur, may be determined with all needful accuracy, even by those little skilled in chemical manipulation, and with very little loss of time. This research has been carried out in the laboratory of the New Haven Gaslight Company. B. SILLIMAN. October 17th, 1876.

Jan 1, 1877

By A. Haas, L. Bubenicek

The Lorraine deposit of minette iron ore has been mined for more than a century. During this time, the economic conditions have changed frequently, and especially during the past decade. Thus, it has become economically prudent to proceed to new iron ore reserves with consideration of many and varied parameters. In the past, only traditional mining parameters were considered. Today, the quantity of information that must be taken into account is of such magnitude that the only practical means of data processing is by use of a digital computer and a mathematical model. One such model, based on geostatistics, was developed by G. Matheron. Much of the required input information, such as the petrology of ores, has been generated through IRSID investigations. This paper deals with several aspects of data processing in mining including information recording, reserves calculation, and stages of shrinking data in the calculation of mining iron beds, variograms, kriging, and tonnages.

Jan 1, 1969

By Robert W. Bartlett

A computer model for predicting the rate of oxidative leaching of copper from fragmented low grade sulfide ores is presented. The model involves the kinetics of the dissolution of chalcopyrite grains and solution diffusion of oxygen within rock pores. Adjustable curve fitting parameters are not used. The model was tested by comparing computed extraction curves with experimental results for a -11 inch ore obtained by block caving and leached at 90°C and 400 psi oxygen for one year at the Lawrence Livermore Laboratories.

Jan 1, 1973

By R. W. Nelson

The theoretical basis is presented for energy dissipation methods of measuring permeability in saturated heterogeneous media. Analysis starts with the equation for single-phase flow in heterogeneous porous media which is a first-order partial differential equation in the unknown permeability. This equation is reduced to a system of characteristic equations useful in deriving a differential expression for the permeability as a function of the known potential distribution. For steady flow systems the expression is integrable, giving the permeability integral for direct calculation of the distribution along successive streamlines. The boundary condition in permeability is presented and includes a discussion of the special requirement to assure uniqueness. Theoretical results and necessary computations are incorporated into two general computer programs capable of determining the permeability distribution in two- and three-dimensional steady flow systems. Results are then presented for an energy dissipation analysis using the methods and soltware to determine a field permeability thickness distribution. INTRODUCTION Theoretical work leading to the description of fluid flow in heterogeneous porous media has developed slowly and somewhat sporadically, although the areas of engineering applications predominantly involve flow in nonhomogeneous media. The lack of accurate and economical methods for measuring field permeability distributions has been a major limitation to realistic description of natural flow systems. The economical measurement of permeability using energy dissipation methods may overcome this limitation. Among other things, any permeability measurement method involves consideration of energy dissipation; as used here, "energy dissipation method" denotes the following general approach. The areal energy distribution is measured on an existing flow system in porous media. Then through appropriate analysis of the dissipation of energy in the flow system, the permeability distribution is determined throughout the region using the minimum boundary conditions required to assure a mathematically unique result. This paper presents the theoretical basis for such a method, as well as the techniques and computer software needed to carry out the analysis. The method and techniques are then used in a preliminary field application. EQUATIONS DESCRIBING FLOW IN HETEROGENEOUS MEDLA Heterogeneous as used here implies differing in kind, having unlike quantities or possessing different characteristics. Accordingly, a heterogeneous porous medium has unlike quantities or differing characteristics at different locations. More precisely, if a porous medium is heterogeneous with respect to some property, then that property is functionally dependent on the spatial location. (Media properties are considered here as macroscopic.) Specifically considering permeability k,** then k = G(x, y, z) ,............(1) or the permeability is a scalar function G of the location (x, y, z). Spatial variation of several other properties, of which porosity, dispersivity and medium compressibility are but a few, is implied by the broad title of heterogeneous porous media. The term will be used hereafter to imply only heterogeneity with respect to permeability. The porous medium is considered isotropic as implied by G being only a scalar function. Anisotropy

Jan 1, 1969

By P. F. Gnirk, J. B. Cheatham

The results of combined analytical and experimental studies involving simulated multiple bit-tooth penetration into mck are incorporated into a drilling rate equation for roller-cone bits assuming rather idealized downhole conditions. In particular, it is assumed that the rock behaves statically in a ductile fashion during bit-tooth penetration and that the rock chips are instantaneously removed from the bottom of the drill hole. The general analysis demonstrates an application of plasticity theory for the rock/bit-tooth interaction to the formulation of an upper limit on rotary drilling rate. INTRODUCTION Extensive experimentation involving single and indexed bit-tooth penetration into rock in a confining pressure environment has demonstrated that the chip formation process is of a ductile, or pseudoplastic, nature at sufficiently low differential pressures so as to be of interest in rotary drilling. Coincident with the experimentation, analytical consideration has been given to the theoretical problems of single and indexed bit-tooth penetration into rock. In general, the analyses have assumed that the rock behaves statically in a rigid-plastic fashion and obeys the Mohr-Coulomb yield criterion. The quantitative comparison between experimental and calculated values of bit-tooth load required for chip formation has been remarkably good for a variety of rocks commonly encountered in drilling and at simulated differential pressures as low as 500 to 1,000 psi. Results obtained recently for indexed bit-tooth penetration indicate that the work (or energy) required to produce a unit volume of rock chip can be minimized by a proper combination of bit-tooth spacing and bit-tooth load for a given rock type and differential pressure. By utilizing this information, it is possible to formulate a drilling rate equation, at least in a preliminary fashion, for a roller-cone bit performing under rather idealized downhole conditions. In particular, through the use of characteristic dimensionless quantities pertinent to a roller-cone bit and to indexed bit-tooth penetration, interrelationships among bit weight, rotary speed, rotary power, bit diameter, rock strength and bit-tooth shape and spacing can be explicitly expressed. In the formulation of the equations, however, it is assumed that the rock chips are instantaneously removed from the bottom of the drill hole and- that the rock behaves in a ductile manner during bit-tooth penetration. In addition, the effects of bit-tooth load application and penetration by a yawed tooth at an oblique angle are neglected. Although the analysis is presented in the light of some rather restrictive conditions, it does demonstrate a method of applying fundamental rock/bit-tooth interaction data, obtained by combining the results of analysis and experiment to the formulation of a drilling rate equation for rotary drilling. JNDEXED BIT-TOOTH/ROCK INTERACTION PREVIOUS RESULTS The mechanics of bit-tooth/rock interaction under simulated conditions of borehole environment have been extensively described in a number of papers.l-ll In particular, the effects of differential pressure, mechanical properties of rock, pore fluid, bit-tooth shape and spacing, rate of bit-tooth load application and dynamic filtration below the bit-tooth have been investigated experimentally. From a sequence of experiments.1-4 it was demonstrated that, for dry rock at atmospheric pore pressure, the mode of chip formation exhibits a transition, with increasing confining pressure, from predominantly brittle to predominantly ductile. This transition

Jan 1, 1970

By A. B. Hildebrandt

P. B. Baxendell is to be complimented for an exccllent piece of work. To our knowledge there has been no previous publication of field data on the flow of oil and gas through the annulus of a well. It is certainly gratifying to see this work on annular flow confirm the previous published correlation procedure on tubing flow. It extends considerably the range under which reliable gas-lift calculations can be made. Baxendell discussed this work with us about a year ago and was kind enough to send a large scale plot of his correlation. We had been designing gas-lift installations on flow through the annulus, assuming that the original correlation of the f factor based on tubing flow' was valid as long as we stayed within the same mass velocity range on which the correlation was based. Doing this work necessitated the use of an equivalent diameter for the annular flow. The equivalent diameter is defined as area' of stream cross section wetted perimeter and for the case of an annulus is D, — D,. Substituting this in the basic equation correlating energy loss along with the area to flow required to convert the velocity, to volumetric flow rate, D (Baxendell's Eq. 7) becomes dell's expression, D,). Similarly, the D in 1.4737 X 10 (M&/D) becomes (D, + D;) for annular flow. On receipt of Baxendell's data, we. of course, recalculated it to put it into the form we were using, and to see how well it agreed with the correlation based on tubing flow. Fig. 1 shows the results, which were certainly gratifying. For low values of (D, - D,) pv, the data coincide with the data on flow through tubing, whereas at high values the data on flow through the annuli appear to be leveling off to a constant value. For very high rates of flow where the turbulence is very high, one might expect the value f to level out and become constant. A bulletin published in 1914 by the U. of Wisconsin presented results of a large number of laboratory teats in air lifting water through short lengths of 1.25-in. tubing. It was possible to correlate a random sampling of

By Charles H. White

+1HARVARD UNIVERSITY, CAMBRIDGE, MASS. The equipment of a laboratory in which students are to be trained for practical work in metallurgical chemistry presents many difficulties not encountered in the fitting up of a commercial or works laboratory. At an industrial plant the chemical work required usually demands the frequent repetition of a comparatively limited number of methods. In a steel-works laboratory, for instance, by far the larger part of the work consists in making determinations of the usual impurities found in iron and steel; at a smelter the great bulk of the work is confined to the analysis of ores, slags, mattes, and fuels, which involve the frequent application of perhaps not more than a dozen different methods. In a laboratory of this character, therefore, those operations most frequently applied may each have a certain section set apart and fitted permanently with such apparatus as best facilitates the carrying out of this one operation. The work of a commercial or custom laboratory is perhaps more varied than that of a works laboratory, but the couditions are similar in these respects, that there is usually no great need for economy of space, and that a few skilled workmen are employed to carry the determinations through from beginning to end without interruption. On the other hand, the laboratory of a technical school should be planned on such a scale that a comparatively large number of students may work at the same time, and each desk should be equipped for general metallurgical analysis. In most institutions for technical education the student's program is so arranged that his day is divided among several subjects in the course of study; only a few consecutive hours being devoted to one subject, or spent in one laboratory. Therefore, those appliances should be provided that render possible the safe continuation of such processes as

Jan 1, 1905

By W. O. Philbrook, H. W. Hosking, N. B. Melcher

A simple and inexpensive mercury-tracer method has been develohed to study rates and Patterns of gas flow in blast furnaces. A Pulse of mercury is injected into the hot blast, and its arrival at the sampling Point is recorded by an electronic circuit that measures resonant absorbtion of ultraviolet light by mercury vapor in the gas aspirated .through the detecting. cell. A rapidly developing interest in blast-furnace technology in recent years has created a strong demand for precise knowledge of the rates and patterns of gas movement through the stock column. Classical fluid-flow theory cannot supply the desired information because the complexity of the blast-furnace situation precludes the accurate determination of many of the parameters required for solution of the equations. In fact some of the terms employed in fluid-flow treatments become almost meaningless under blast-furnace conditions. The void fraction of the stock column, for example, varies widely from place to place and is affected by the segregation of charge materials, attrition of lumps during descent, and channeling. Gas density varies with changes in local pressure, temperature, and composition, while viscosity varies with temperature and composition. Even if mean values for these functions were acceptable, they would be either impossible or extremely difficult to determine with a high degree of accuracy since the value of the mean for all gas properties would depend upon the flow distribution itself. Attempts to study gas movement by the pitot-tube determination of kinetic pressures have met with little acceptance. Reproducibility of results is extremely difficult to achieve in a situation where alignment of the tube orifice with respect to the flow direction in tortuous channels cannot be guaranteed. Because of these difficulties it would appear that progress can be achieved only with a direct method of measuring gas velocities and determining the shape of flow paths through the stock. The establishment of such a method is described in this paper. SELECTION OF METHOD Direct measurement suggests the use of a tracer by means of which the progress of a "parcel" of gas can be followed through the furnace. Several requirements must be met before any selected material can be considered a suitable tracer. First of all, it must be a substance not normally present in blastfurnace gas or dust; otherwise its presence in a gas sample will have little significance. It should be volatile at temperatures normally existing within the furnace, to ensure that it will travel with the gas, as a gas. It should possess special properties enabling its presence in the gas to be detected readily, and it should not undergo exchange reactions with any material normally present within the furnace, including refractories and coke as well as all components of the metal and slag. Radioactive materials naturally are considered because their radioactivity renders them susceptible to detection. However, of the many radioactive materials available, almost all are eliminated from final consideration by their unsuitability in terms of other properties. Radioactive silicon, carbon, calcium, phosphorus, and many others have been considered and discarded, either because they are not volatile over the whole range of significant temperatures, or because they could be expected to undergo exchange reactions with burden or refractory materials. Others which might be suitable in terms of these properties are eliminated because of a low activity, short half life, or the necessity for fragile counting apparatus. Of the many elements available in radioactive form, perhaps radon is the only one suitable for blast-furnace gas-flow studies. This has been used in several investigations1-4 with considerable success. The use of radiotracers has certain inherent disadvantages. One is the cost. An appreciable sum must be allowed for materials each time a test is made. Also, special methods of handling must be employed, and very often the progress of an investigation must be governed by the availability of isotopes and the delivery arrangements that can be made for them. An advantage is immediately gained if the tracer material can be a substance which can

Jan 1, 1960

By H. H. Evinger, M. Muskat

A methoD of calculating productivity factors for oil, gas, and water systems in the steady state is presented as an illustration of the quantitative application of the fundamental data on the flow properties of heterogeneous fluid systems. While the numerical results of the calculations cannot be applied directly to field conditions, because they are based on permea-bility data for unconsolidated sands and involve specific assumptions regarding the nature of the reservoir fluids, the methods of analysis and interpretation should havc significance in considering certain specific field situations when the necessary field and laboratory data become available. Moreover, it is felt that even under the idealized conditions to which the numerical calculations refer they should serve to give at least the orders of magnitude of the effects of gas-oil ratio and connate water on observed productivity factors. Within the indicated limitations, the computations imply that the foregoing factors can explain only a part of the apparent discrepancy between the homogeneous fluid productivity factors and those obtained recently in field measurements on the West Coast. IntroductioN Sufficient laboratory research has been carried out in the last several years on the fundamental features of the flow of heterogeneous fluids through porous media to call for consideration of what can be done with this type of information. It has, of course, already led to a, much clearer general understanding of the mechanics of oil production. However, examples of the quantitative application of the results of such laboratory studies are few in the literature. part of the explanation for this fact lies undoubtedly in the lack of sufficient laboratory data relating to practical fluids and sand systems such as would occur ill actual oil reservoirs. However, unless it can be shown that if such data were obtained quantitative applications could be made, serious doubt may be cast upon the desirability of carrying on further extensive experimental research work on fluid flow. The purpose of this paper is to present one approach to the problem of quantitative application of laboratory data to practical field problems. Because the published results on the basic experiments with three-phase fluid systems in porous media are limited entirely to uncon-solidated sands, the numerical applications made here will not pertain directly to any actual field situation. However, they should serve to illustrate what could be done with fundamental laboratory data if they were extended to cover the field of consolidated sands. From this point of view, it is hoped it will serve to encourage further laboratory research on this problem. The particular application to be treated here relates to the calculation of the productivity factors for oil-gas-water systems in the steady state. This specific problem seems especially appropriate for discussion in view of the recent publication by Johnston1 of the results of produc-

Jan 1, 1942

By M. Muskat, H. H. Evinger

A methoD of calculating productivity factors for oil, gas, and water systems in the steady state is presented as an illustration of the quantitative application of the fundamental data on the flow properties of heterogeneous fluid systems. While the numerical results of the calculations cannot be applied directly to field conditions, because they are based on permea-bility data for unconsolidated sands and involve specific assumptions regarding the nature of the reservoir fluids, the methods of analysis and interpretation should havc significance in considering certain specific field situations when the necessary field and laboratory data become available. Moreover, it is felt that even under the idealized conditions to which the numerical calculations refer they should serve to give at least the orders of magnitude of the effects of gas-oil ratio and connate water on observed productivity factors. Within the indicated limitations, the computations imply that the foregoing factors can explain only a part of the apparent discrepancy between the homogeneous fluid productivity factors and those obtained recently in field measurements on the West Coast. IntroductioN Sufficient laboratory research has been carried out in the last several years on the fundamental features of the flow of heterogeneous fluids through porous media to call for consideration of what can be done with this type of information. It has, of course, already led to a, much clearer general understanding of the mechanics of oil production. However, examples of the quantitative application of the results of such laboratory studies are few in the literature. part of the explanation for this fact lies undoubtedly in the lack of sufficient laboratory data relating to practical fluids and sand systems such as would occur ill actual oil reservoirs. However, unless it can be shown that if such data were obtained quantitative applications could be made, serious doubt may be cast upon the desirability of carrying on further extensive experimental research work on fluid flow. The purpose of this paper is to present one approach to the problem of quantitative application of laboratory data to practical field problems. Because the published results on the basic experiments with three-phase fluid systems in porous media are limited entirely to uncon-solidated sands, the numerical applications made here will not pertain directly to any actual field situation. However, they should serve to illustrate what could be done with fundamental laboratory data if they were extended to cover the field of consolidated sands. From this point of view, it is hoped it will serve to encourage further laboratory research on this problem. The particular application to be treated here relates to the calculation of the productivity factors for oil-gas-water systems in the steady state. This specific problem seems especially appropriate for discussion in view of the recent publication by Johnston1 of the results of produc-

Jan 1, 1942