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By Donald W. Scott, Nathaniel Arbiter, A. C. Richardson

This paper describes the application of amine flotation to a specific problem—that of increasing the grade of magnetite concentrates derived from an iron ore requiring extremely fine grinding for mineral liberation. Experiments conducted on an iron ore from Wisconsin had shown that concentrates containing 60 to 62 per cent iron and 12 to 14 per cent silica could be produced by magnetic separation. The residual silica occurred as quartz and hornblende, either entrained or locked with magnetite. Most advantageous utilization of the concentrate, however, necessitated that the silica content be reduced to about 5 per cent, equivalent to an iron content of 67.5 per cent. It had been demonstrated that tabling of the magnetic concentrate removed sufficient quartz and hornblende to yield an acceptable concentrate, but disadvantages inherent in tabling dictated that flotation be investigated as a substitute. The goals set for the flotation investigation were: (I) the production of concentrates of about 68 per cent iron content from the magnetic concentrate; (2) an iron recovery of about 85 per cent of that in the feed to flotation; and (3) minimum reagent cost. Both batch and continuous flotation tests were employed; the former, to establish the procedure and the latter to verify it. Although the data were obtained on a specific ore, and with a commercial application in view, it is believed that they have a bearing on other problems where amine flotation is being used or is anticipated. Samples Two samples, designated "(minus 100-mesh magnetic concentrate" and "minus 150-mesh magnetic concentrate," were used for the batch experimental work. They differed only in the degree to which the crude ore was ground prior to magnetic separation. They were stored moist in steel drums in quantities sufficient for all the experimental work reported. This procedure had the advantage of allowing all tests to be made on common samples, but had the disadvantage that the individual flotation samples, because of the difference in storage time, were subject to various stages of surface alteration. Previous work had indicated that common samples were desirable for the batch studies, and it was decided that if these data appeared sufficiently promising the effect of surface alteration could be checked best by continuous tests. The size distributions and the assays of the samples are given in Table I. The minus 150-mesh magnetic concentrate, on which most of the flotation tests were made, assayed 60.9 per cent iron, 13.3 per cent silica, and 0.016 per cent phosphorus. The minus 325-mesh portion represented 78.I per cent of the sample by weight, and assayed 67.9 per cent iron. Thus, the insoluble, mainly silica, was concentrated

Jan 1, 1947

By L. B. McConville

The general term "tar sand" refers to sand that contains varying amounts of dense, viscous petroleum. Tar sand deposits have been found throughout the world, often in the same geographical area as conventional petroleum. The largest one by far is known as the Athabasca Tar Sands, in the province of Alberta, Canada. Actually a group of three deposits, these particular sands underlie an aggregate area of more than 12,000 sq miles. Current estimates place the contained raw petroleum at about 700 billion bbl; and via currently available technology, the amount of recoverable synthetic oil may be as much as 300 billion bbl-which is roughly equivalent to five times the combined US and Canadian total crude oil reserves. With the ever-widening gap between energy supply and demand, mining and petroleum companies are now evaluating all possible energy resources-both developed and underdeveloped-and, certainly, the Athabasca Tar Sand deposit is one of the more important ones to merit such attention. The first section in ME deals with the geology and historical developments; the other four sections, with mining methods, extraction technology, economics, and outlook.

Jan 1, 1975

By C. O. Swanson

In the iron ranges of northern Michigan, magnetic data have been used as an aid in geologic field work since the time of the earliest surveys. The presence of complex structures containing magnetic formations, and the general scarcity of exposures, guided the early work into this line of attack, and later field studies tended to place more and more emphasis upon this geophysical relationship, until, at present, the collection of magnetic data is a matter of routine in any areal survey. At first, horizontal deflections of the compass needle were the only data collected. In subsequent surveys, greater dependence was placed on dip-needle readings, which record variations in the intensity and inclination of the earth's magnetic field. Recently the trend has been toward adjusting the instrument so as to reduce the influence of changes in inclination, and using a more sensitive modification, called the Superdip,' in weakly magnetic areas. To a minor extent, the magnetometer has also been employed. The object of this paper is to present the writer's experience with magnetic data in this region. The conclusions are based on work covering a period of 10 years, and spread over nearly all of the iron ranges and a large part of the intervening areas. The viewpoints expressed are purely geological ones. In other words, any opinion as to the usefulness of a certain relationship is based upon the writer's experience with it as a guide in interpreting the structures of this region, and not upon its soundness theoretically, nor its usefulness under other conditions. A very brief summary of the conclusions is as follows. The most important step is that of collecting the magnetic data. This requires a suitable adjustment of the dip needle, and sufficient readings to accurately portray the variations in the magnetic field, which are apt to be irregular. Once the readings are taken and plotted in some clear fashion, the interpretation of them is usually merely a matter of observing their relation-

Jan 1, 1934

By Paul D. Merica, R. G. Waltenberg

Although nickel was discovered and isolated as early as 1750 and its valuable properties recognized, many years passed before it was used commercially for wire, sheet, rods, etc., in the pure form. This was due partly to its high cost at that time and partly to the fact that it was not possible to refine and cast nickel into ingots sufficiently malleable to be amenable to the usual forging, rolling, or drawing processes. So remarkable was this fact, and so different from the experience at that time with metals such as copper and iron, that it has left its impress on the nomenclature within the nickel industry. To this day, furnace-cast nickel produced in such a manner as to be suitable for rolling and forging is called malleable nickel to distinguish it from the ordinary pig and shot nickel of commerce. In 1878, the firm of Jos. Wharton, of Philadelphia (which later became The American Nickel Works, a constituent of The International Nickel Co.) exhibited at the Paris Exhibition specimens of rolled pure nickel strip and of drawn nickel wire. About this time, there was considerable activity in the study of the refining of nickel and several methods were described, some of which were patented, for the production of furnace-cast malleable nickel including the use of manganese (Boed-dicker,1 Selve and Lotter2), the use of potassium permanganate (Berns-dorfer Metallwarenfabrik3) and the use of phosphorus (Garnier4). By far the most efficient method was discovered by Th. Fleitmann in 1879;5 it consisted in adding to the molten nickel, just before pouring the castings, from 0.05 to 0.125 per cent. of metallic magnesium. This soon became the recognized final malleableizing treatment for furnace-cast nickel.

Jan 1, 1925

By Kenneth C. Vincent, A. M. Gaudin

In a study1 of the action of amyl xan-thate on chalcocite in water suspension, it was found that if the xanthate is added in relatively large quantity the xanthate group can be accounted for in three forms: (1) as xanthate ion remaining in water, (2) as benzene-soluble cuprous xanthate on the chalcocite, (3) as a benzene-insoluble coating on the chalcocite. Reduction in the amount of xanthate added leads to disappearance of form I then of form 2. With minute quantities of added xanthate, substantially all the reagent is of the "unleachable" kind. Yet this unleach-able xanthate can be dissolved by pyridine to form a soluble cuprous xanthate complex, and it is sufficient in effectiveness to make chalcocite flotable even if insufficient in quantity to form a complete mono-molecular film on the mineral. In that study it was also found that chalcocite abstracts cuprous xanthate from benzene so1ution, in what may (or may not) be a case of molecular adsorption. It seemed desirable, therefore, to study further the "unleachable" xanthate on the chalcocite, and particularly to ascertain whether it is formed as a result of the benzene leach or is actually formed during the conditioning of chalcocite in aqueous xanthate solution. A 'splendid tool to make such studies has recently been perfected; that is, the use of radioactive spies or tracer atoms. With this tool, it was thought possible to answer the problem stated above, but, unfortunately, this did not prove to be true. Answer to the flotation question was clouded by the existence of rapid and selective diffusion of copper atoms in the solid mineral—a phenomenon that was totally unexpected yet remains interesting and perhaps important. Method of Radioactive Spies The method of radioactive spies is discussed in many places. Two convenient references are the article by Evans2 and the book by pollard and Davidson.3 The method was first developed by van Hevesy and paneth in 1013, when only natural radioactive isotopes were available. These isotopes are few in number, and so the method remained limited in scope. Recently the synthesis of over 350 active isotopes of all the known stable chemical elements4 has opened widely expanded possibilities for the method, A fundamental tenet of the method is that a radioactive atom and a nonradio-active atom are exactly alike until disintegration of the radioactive atom. Then, by its sudden death, the spy reveals its location. The relative abundance of spies at various locations makes it possible to ascertain the relative abundance of the corresponding nonradioactive atoms at the same times and locations. A second fundamental tenet of the method of radioactive tracers is that the radioactivity lies in the nucleus of the atom: transfer of radioactivity from one

Jan 1, 1947

By D. H. Davis, I. Fatt

Oil bearing rocks, usually found at depths of 2,000 to 10,000 it, are elastically deformed by overburden pressure. Although the change in porosity with pressure in a number of example rock.: has been shown to be small, it was thought that overburden pressure might have a significant effect on permeability. This note presents results of an investigation to determine the magnitude of the change in permeabilty with pressure. In routine core analysis permeabilities are measured on rock samples which are not under overburden pressure. If permeablity measured in this way differs from permeabilities measured under overburden pressure, a systematic error is introduced into well productivity calculations. The experiments described in this report were made to determine the magnitude of the change and thus to give an estimate of the error introduced into the calculations. The error introduced by the neglect of the change in permeability when overburden pressure is removed may account for part of the difference between well productivity calculated from core analysis and the actual well productivity. The results obtained in this investigation have only quali-tative significance because of the difficulty in reproducing in the laboratory the stress conditions on the rock buried in the earth. The assumption which is usually made is that the rocks in the earth are under a uniform pressure equal to the weight per unit area of the vertical overburden column from the rock in question to the surface of the earth less the pressure of the liquid in the pores of the rock. For an overburden consisting of sandstones and shales (of assumed average specific gravity of 2.3) and for a liquid pressure equal to the pressure in a salt water column (of specific gravity 1.0) reaching from the rock to the surface, the resulting net pressure on the rock is approximately 0.56 psi per ft of depth. EXPERIMENTAL METHOD Clean, dry sandstone core plugs one in. in diameter and about three in. long were mounted in a copper foil jacket as shown in Fig. 3 or molded in a Lucite jacket as shown in Fig. 4. All cores except those labeled "2" in Fig. 1 and "8" in Fig. 2 were measured in the copper foil jacket. Cores "2" and "8" were measured in the Lucite jacket. The jacketed core was placed in a high pressure hydraulic bomb in which the liquid pressure outside the jacket could be raised to 15,000 psi. Flow lines from the core were brought out of the bomb through special fittings in the bomh head and connected to a laboratory type gas permeameter. Measurements were made with nitrogen gas; the maximum mean gas pressure in the core was 16.1 psia. RESULTS The specific permeability of sandstone decreases with in. crease in overburden pressure. Most of the decrease takes place over the range of zero to 3,000 psi overburden pressure. If the net pressure on the rock is assumed to be 0.56 psi per ft of depth as discussed above, 3,000 psi of overburden pressure is equivalent to about 5,000 ft of overburden. At 3,000 psi overburden pressure, the permeability of the eight sandstone core samples tested ranged from 59 to 89 per cent of the permeability without overburden pressure. Figs. 1 and 2 show the permeability reduction as a function of overburden pressure. The permeability of the eight cores without overburden pressure ranged from 4.35 md to 632 md; these permeabilities are listed in Figs. 1 and 2. REFERENCES 1. Carpenter and Spencer: "Measurements of Compressibility of Consolidated Oil Bearing Sands," U. S. Bureau of Mines, R.I. 3450, (1940). * * *

Jan 1, 1952

By E. C. Bohlen, H. l. Burghoff

THE work reported in this paper was carried out to supplement the existing information concerning directional properties and recrystallization textures of annealed brass sheet and strip. These characteristics are of direct interest when the forming and drawing properties of such material are being considered. Among those who have made contributions in this field are Bass and Glocker;1 Bauer, Göler and Sachs;2 Phillips and Samans;3 Pratt;4 Price;5 Cook;6 Richards;7 Brick;8 and Brick and Williamson.9 These investigators have found, in general, that in brass strip that shows directional variations in properties, tensile strength has a minimum value and elongation has a maximum value at 45° to the rolling direction. The most pronounced directional properties have been found in material given the greatest reductions in rolling followed by high annealing temperatures. Recrystallization texture of brass has been variously reported as (113)[112], (001)[100], and a combination of (110)[115] and traces of the primary rolling texture, (110)[112]. The directional studies have been very informative, but actual tests appear to have been confined to material in its final condition. Tests at intermediate stages have received little attention although previous history of some materials has been partly considered. Perhaps the most comprehensive investigation was made by Cook,6 who studied the directional properties of 70-30 brass strip for which the final and penultimate, or next to the last, anneals and the final reductions were varied. He found that, for any given combination of penultimate anneal and final reduction, the tendency toward the development of directional properties was reduced as the temperature of the final anneal was decreased. In addition to drawing cups and making tensile tests of the finished material at various angles to the rolling direction, he measured the frequency and the angles of twins in grains for several specimens. Plots of his twin counts showed directionality for the materials that produced eared cups. TEST MATERIALS AND EQUIPMENT For this investigation, one commercial heat of 68-32 brass was cast in the form of bars for cold-rolling, 13 ½ in. wide and 1 ½ in. thick. The analysis was as follows: 68.83 per cent copper, 0.04 per cent lead, 0.01 per cent iron, 31.12 per cent zinc (by difference). The bars were so processed to the final thickness, 0.020 in., as to obtain on this thickness all possible combinations of the variables listed below except those involving the sequence of 84 per cent penultimate reduction and 84 per cent final reduction: I. Penultimate reductions of 37 per cent, 50 per cent and 84 per cent; 2. Penultimate anneals at 800°, 900°, 1050° and 1200°F.; 3. Final reductions of 37 per cent, 50 per cent, 69 per cent and 84 per cent;

Jan 1, 1942

By C. Ernest Birchenall, Robert F. Mehl

APPLICATION of diffusion laws in the customary form to experimental studies in binary metallic solid solutions has shown the diffusion coefficient to vary with concentration for all systems investigated. The factors determining this variation have not been ascertained. However, the question of whether the diffusion coefficient would become a constant, independent of concentration throughout a single phase if the concentration gradient in the diffusion equation were replaced by an activity gradient has been an attractive subject for speculation. Wagner1 derived an expression for the force acting on a diffusing particle in terms of the chemical potential. This was also the approach chosen by Jost2 in his monograph. From a somewhat different point of view, Eyring3 and his co-workers have used activity gradients when dealing with diffusion in concentrated nonideal solutions. The only actual test with experimental data is that given by Darken,4 though this is more qualitative than quantitative. Many others opposed the application in any way of thermodynamic concepts to kinetic phenomena, including diffusion processes. A rigorous examination of this principle requires good data expressing the relationship between activity and concentration for solid solutions for which reliable diffusion work has been done. The literature provides such information only for the interstitial solution of carbon in gamma iron (austenite) and for the substitutional copper-zinc solutions (alpha brass). Activity data for carbon in austenite at 800°C and 1000°C are available from the recent work of Smiths on the equilibrium of hydrogen-methane and carbon monoxide-carbon dioxide mixtures with gamma iron. Combining these with the diffusion studies of Wells and Mehl6 makes possible a quantitative test for this interstitial solid solution. The vapor-pressure determinations for zinc over brass by Hargreaves7 allowed the calculation of activities in this system over a wide range of temperatures and concentrations. Extensive investigation of diffusion in this substitutional solid solution has been carried out by Rhines and Mehl.8 ACTIVITIES IN BRASS9 If the vapor phase of zinc is assumed to behave as an ideal gas, any solid or liquid solutions that are in equilibrium with the same partial pressure of zinc at the same temperature have the same thermodynamic activity of zinc. In order to assign a numerical value to the activity azn, it is necessary to choose some standard reference state to which an activity value of unity is arbitrarily assigned. It is customary to choose the liquid or solid state of the pure material. Then azn is defined numerically by azn = Pza/Pzn° [I]

Jan 1, 1947

By John Wulff, J. H. Hollomon

THE opinion has been widely held that the corrosion of alpha brass occurs by the selective solution of zinc. As late as 1939, Fink1 and Evans2 suggested that in the initial stage of the corrosion the selective solution of zinc produces copper-rich areas, which subsequently act as cathodes that facilitate the deposition of copper. Previously Abrams3 had shown that most of the copper found on corroded brass was redeposited and not residual, although he did not consider the nature of the initiation of the corrosion process. Enough data exist to indicate that any metal surface is sufficiently heterogeneous to provide the anodes and cathodes necessary for the initiation of corrosion.4,5 Thus, for alpha brass we need postulate not an initial selective solution of zinc, but only the existence of local differences in electrochemical potential. The heterogeneity responsible for potential differences may arise from oxide and other films as well as from alloy concentration gradients. Even though selective corrosion may be possible in some alloy systems, previous data on alpha brass as well as the experimental work reported in this paper do not require this supposition. Bengough and May,6 in a discussion of Abrams' paper, first suggested the addition of small amounts of arsenic (0.03 per cent) to alpha brass to prevent the redeposition of copper (dezincification). This suggestion was later substantiated by Nixon.7 In their studies of the inhibiting influence of arsenic, Evans and Fink were led to the selective-solution hypothesis in order to explain the initial corrosion of such alloys. They believed that an arsenic film covered anode areas and prevented the formation of copper-rich spots capable of acting as cathodes for the deposition of copper. They did not consider, however, the mechanism by which the arsenical film was formed. Bengough and May,8 in another publication, suggested that the commonly found gray or black arsenical film may act to: (I) carry oxygen to the brass surface, (2) increase the discharge potential of copper on brass, (3) precipitate cuprous chloride from colloidal suspension in chloride solutions. Masing9 assumed that the film found upon arsenical brass was metallic arsenic. His measurements of hydrogen overvoltage of bulk arsenic led him to believe that the inhibition of dezincification occurs because the overvoltage of a brass surface is lowered by the arsenic film. He reasoned that this film would permit the more rapid reduction of hydrogen at the cathode, which would prevent the redeposition of copper. In a recent paper,10 we have pointed out that the film formed during the corrosion of arsenical brass and copper in stagnant solutions is essentially arsenious oxide (As203),

Jan 1, 1942

By Clarence Zener

THE heat-treatment of steels will not pass from the stage of an art into that of a science until the mechanism of the phase transformations associated therewith is thoroughly understood. Such an under- standing will involve two distinct types of inquiry: (I) the direction of the trans- formation, (2) the speed of the transformation. The first type of inquiry, which involves only the equilibrium relations between the various phases in steel, is the subject of the present and of a succeeding article; the second type, which involves the kinetics of transformations, will be the subject of a later article. In order that a theory of equilibrium relations may give useful information, certain experimental data must be put into the theory. It is customary for these data to be of a thermal nature. In the system discussed here in steel such thermal data are very scarce. In medium-alloy steels another type of data might possibly be used. In these steels the concentration of solute is so low that it may be possible to use the approximation of dilute solutions, an approximation that leads to linear relationships. The unknown functions, or constants, may then be determined in some cases from the binary iron- alloy system and in other cases from the ternary iron-carbon-alloy system. From the functions, or constants, so determined may then be computed the equilibrium relations in more complex medium-alloy steels. In the present article this second approach is used, the necessary experimental data being obtained from the simple binary and ternary equilibrium diagrams. FUNDAMENTAL EQUATIONS In this article are derived the equilibrium relations between the gamma, alpha and cementite phases. In these three phases all important alloying elements except carbon form substitutional solutions, each alloying atom occupying a potential site for an iron atom. Carbon, on the other hand, forms an interstitial solution. In the face-centered cubic gamma phase, the interstitial positions are at the center of the unit cube and at the centers of the cube edges. There are therefore four interstitial positions per unit cell, or one per iron atom. In the body- centered cubic alpha phase, the interstitial positions are probably at the face centers, and also at the centers of the edges, which are crystallographically equivalent to the face centers. There are therefore six interstitial positions per unit cube, or three per iron atom. In cementite, (Fe, Alloy)3C, the carbon atoms may be regarded as filling all the lattice positions of a given type. The introduction of the fundamental equations of equilibrium has presented the author with a quandary. These equations are formally so similar to other equations that have been derived1,2 for related systems that they may appear to some readers

Jan 1, 1946

By Zay Jeffries

It has been known for centuries that iron and steel could be hardened by cold hammering and that the metal could be restored to the normal condition by heating to a red heat arid cooling, either rapidly or slowly with nearly pure iron, but slowly with steels containing considerable carbon. The art of tempering steels is also very old. When a medium- or high-carbon steel is quenched from a cherry-red heat, the hardness is increased; this hardness can be reduced by heating to various temperatures below the lower thermal critical point,, which is near 700" C. The present paper will not consider these old and well known changes in iron and steel below the thermal critical range but will confine itself to the more unusual changes, some of which have been studied recently. Stromeyer,1 for example, In 1886, reports that both working steel and heat treatment of steel in the blue-heat range arc highly injurious. Recently, however, some metallurgists believe that the straiglltening of warped steel forgings at a blue heat produces a beneficial effect on the metal2 The Engineering Division of the National Research Council has constituted a committee on Physical Changes in Iron and Steel below the Thermal Critical Range, which has the following personnel: K. R. -Abbott, H. C. Boynton, William Campbell, J. V. Emmons, F. B. Foley, H. J. French, H. M. Howe, Zay Jeffries (chairman), F. C. Langenberg, J. A. Mathews, P. D. Merica, A. H. Miller, J. H. Nelson, G. A. Reinhardt, W. E. Ruder, H. F. Wood. This committee is studying several aspects of the physical changes in iron and steel. The results, reported in the literature and obtained by recent experimentation, will be given; this will be followed by a general theoretical discussion of the more important

Jan 1, 1922

By Earl W. Palmer, Cyril Stanley Smith

A study of the precipitation-hardening of copper steels1 led the authors to investigate malleable iron containing copper, for the low-carbon ferritic matrix in malleable iron should lend itself admirably to precipitation-hardening. It was soon found that in addition to rendering malleable iron susceptible to improvement by precipitation-hardening treatments, copper has another potentially useful effect as an accelerator of graphitization. Brief mention of these effects was given in a general paper by Lorig and one of the present authors2; the present paper gives further details on the graphitization and precipitation-hardening effects only. After the completion of this work a paper by L. Lykkin3 appeared, confirming the authors' conclusions regarding graphitization. Material Used After some preliminary heats had been made in the laboratory to determine the effect of copper, several castings from commercial air-furnace heats were obtained, and data from these alone are given here. Part of the metal was poured directly and part was treated in the ladle with the desired amount of copper before pouring. Green-sand molds were used, each holding two tensile test pieces of the form adopted by the Malleable Iron Research Institute, or two bars for graphitization studies, 5/8 in, in diameter and 9 in. long, fed through two enlarged sections equidistant from the middle and ends of the bars. Risers of suitable size insured sound castings. Tensile tests were made on the castings after commercial mallealleizing and after special heat treatments to be described. The analyses of the white irons are given in Table 1.

Jan 1, 1935

By Charles R. Austiuon, Carll H. Samans

It has been known for several years1 that certain alloys of the Konal type, containing commercial cobalt (99.32 per cent Co and 0.42 per cent Ni) and varying amounts of ferrotitanium, exhibit very high tensile strengths at 600°C. However, their proportional limits and yield pints are relatively low. published data' for the alloys quenched in water from 950°C. and then tested at 600°C. are summarized in the upper section of Fig. I. Similar specimens that were aged at 650°C. for 72 hr., after quench and prior to testing at 600°C., gave the result; shown in the: lower section of Fig. I. In the present work the investigation of the properties of these materials has been extended by a study of the tensile deformation characteristics in moderately longtime tests at 600°, 700' and 800°C. after quenching from various solution temperatures. In addition, some metallographic studies have been made to correlate with the deformation tests, and to obtain information on the quasi-binary system cobalt-Fe2Ti. The material, very kindly furnished by the Westinghouse Electric and Manufacturing Co. in the form of hot-swaged rods of 3/16-in. diameter, analyzed as shown in Table 1. The alloys, when originally made up,' were based upon an iron-titanium compound, Fe3Ti, as indicated by the work of

Jan 1, 1941

By Robert B Sosman

The relative temperature distribution within a coke oven and among the ovens in a battery can be obtained automatically for the operator's guidance by sighting a total-radiation pyrometer on the face of the coke as it is pushed out, and recording the surface temperature. Keeping the instrument clean and keeping its view of the coke unobstructed by smoke and dust are the principal problems. Typical records from three plants are presented in this paper, showing that the temperature patterns are reproducible. Development OF Method The method of coke pyrometry described in this paper was introduced in 1936 by E. A. Lee, then Assistant Superintendent, now Superintendent, of the Coke Plant at Lorain Works, National Tube Co., Lorain, Ohio. At the request of the Coke Committee of the United States Steel Corporation, the Research Laboratory of the Corporation undertook to adapt the method to the somewhat different conditions met with at the Gary Works of the Carnegie-Illinois Steel Corporation, Gary, Ind., and at the Clairton Works of the same Corporation at Clairton, Pa. This work was done in cooperation with the Leeds and Northrup Co. of Philadelphia and later with the Brown Instrument Co. Division of Minneapolis-Honeywell Regulator Co., Philadelphia. We of the Research Laboratory wish to express our appreci- ation of the courtesies extended by Mr. Lee, by A. N. Cole, Superintendent of the Gary coke plant, and by D. P. Finney, Assistant General Superintendent in charge of coke-plant operations at Clairton. We are also indebted to the instrument companies for the loan of a part of the equipment. At Gary and Clairton the instruments were installed and various experiments were made by J. W. Bain, of the Research Laboratory of the United States Steel Corporation. Pyrometry of Coke The coke inside a by-product oven is almost completely inaccessible to pyro-metric instruments. The temperature in the walls can conceivably be measured with thermocouples, but the atmosphere is usually strongly reducing, a condition well known to be destructive to the accuracy of the customary high-temperature couples. In some plants, periodic readings are taken with an optical pyrometer sighted into the top of the combustion flues. This is a useful measure for safety and general control, as it tends to prevent the damage that would result from overheating of the ovens. It does not, however, tell much about the temperature of the coke itself, because of the continually changing gradient in the wall between the coke and the combustion chamber. The best indication of the temperature of the coke itself must therefore be obtained by observation of the product as it is pushed out of the oven. The human eye is very sensitive to variations in brightness of a surface, and particularly to differences in brightness over a continuous hot surface.

Jan 1, 1943

By J. M. Bugbee

The engineer and the conservationist agree that effective water drive is the desirable reservoir production mechanism. Water drive may result either from the expansion of edge water, the reservoir water bordering an oil pool, or from the artesian flow of edge water from the outcrop. Thus, the extent of the reservoir has an important bearing upon both the rate and the ultimate quantity of water influx to an oil pool. Lens-type reservoirs are generally recognizable, but the complete structure of the more important domal types, having possible limitations from crestal and synclinal faulting, is not well understood. The delineation from cores, electrical logs and exploitation phenomena of the crestal portions of reservoirs is increasingly exact. This paper suggests that inference from these factual pictures, combined with the scattered well and geophysical data of the synclines and with consideration of the dynamics of structural formation, may be applied to solving the complete geologic structure. Since faulting on the domes and in the synclines may effectively seal and thus limit the size of a reservoir and bar additional water influx, consideration of geologic structure and its possible effects is essential to complete analysis and prediction of reservoir performance. Introduction Implicit in reservoir studies is the fact that the oil must be displaced from the reservoir rock by some other fluid, either gas or water, and this understanding yields the terms descriptive of the major reservoir production mechanisms, gas expansion and water drive' Three recent papers1-2-3 make clear the economic and conservation preeminence of Water drive as a production mechanism; in fact, the title of the latest of these is " Production under Effective Water Drive as a Standard for Conservation Practice." There appears to be an assumption at times among analysts that the effectiveness of a water drive is solely dependent on the rate of oil production; that is, if water drive appears to be insufficient or lacking, a lower oil-recovery rate would increase or reveal it. This assumption might result from the fact that the analysis has been wholly developed during the period of production curtailment; that is, since 1929. The writer takes it that the recurrent phrase in De Golyer's paper,3 "some degree of water drive," is related to this assumption. In California, an extraordinary phrase, "inactive water drive," is rather common and the connotation of uncertainty regarding our knowledge of reservoir performance is evident. Wyckoff2 speaks of the type of reservoir and performance as follows: "In general, reservoirs may be any one or a combination of domal, faulted, lenticular, or stratigraphic traps. Insofar as the dynamic performance of such reservoirs is concerned, the particular type merely determines whether regional flow is symmetrical as in a uniformly developed domal or lenticular type, or one-sided as in many stratigraphic or faulted traps." But whether the flow is

Jan 1, 1943

By Robert S. Moehlman

Is recent years, exploration and development by diamond drilling has become a popular attack on the problem of finding new ore shoots and developing extensions of known shoots. Diamond drilling has been used in recent years in extensive sampling of disseminated copper deposits, in preference to churn drilling. At the Harvard gold mine, near Jamestown, California, Philip R. Bradley, Jr., general superintendent, reports that: "The Harvard work was a singular example of the reliance that can be placed on diamond drilling in evaluating an ore body." Drilling at the Harvard mine will be discussed in a subsequent section of the paper. So popular has diamond drilling become, indeed, that many who have had slight experience with drilling are inclined to regard it as a cheap cure-all. This paper proposes to show some of the limitations on the application of drilling and some of the steps that should be followed in drilling programs to obtain reliable results. Cost oF Drilling Drilling has the advantage, over shaft sinking and drifting, of lower cost and greater speed. As compared with churn drilling, the advantage of bringing up a coherent sample instead of fine cuttings for a sample is obvious. Diamond drilling is generally more expensive, however, and more engineering effort is required in combining the average of core and sludge samples. Exploration of drift walls by hammer drills to a depth of less than 30 ft. is generally cheaper than diamond drilling, but beyond this depth the diamond drill is cheaper and more efficient. The principal factor in determining cost of drilling is the character of the ground drilled. Broken ground with many fissures is most expensive to drill. Hard ground is less of a problem with diamond drills than with ordinary machine drills. Hardness or softness affects only the speed of drilling. Caving, easily washed, sandy or clayey ground requires continual cementing and casing, which is the greatest cost problem. Thus, soft, incompetent ground is more costly to drill than hard, massive ground. Cost of drilling per foot in good to fair ground varies from less than $I per foot, achieved in some districts in Ontario, the Mother Lode, and Missouri, to $5 per foot in many western states. In bad drilling ground, costs may range from $5 to $15 or more per foot, thus approaching the cost of drifting. Other factors that increase the cost per foot are: I. Short total length of hole drilled, so that the cost of moving in crews and equipment must be spread over a relatively few feet. 2. Cost of drilling per foot increases with depth beyond about 500 ft.. as more time is consumed in pulling rods' 3. Cost of preparing drilling stations, getting air underground to stations? etc' 4. Inaccessibility and lack of water on the job make for higher costs.

Jan 1, 1946

By J. S. Lasater

Resu1ts of experinmental measurernents of heat capacities and thermal conductivities of some typical porous rocks are presented. Measured heat capacities agree closely with va1ues calculated front known chenlical . compositions of the rocks. On the basis of this agreement, heat capacitir.7 of fluid-satttrated rocks were calc~ililted. Therrnal conductivities of the rock samples were measured under varioits conditions of fluid saturation. From these data therrnal dif-fvsivities were calculated. A significant variation of thermal diflusivity with trnlperature is indicated. Knowledge of the thermal characteristics of fluid-bearing porous rocks has become increasingly important with the development of thermal oil-recovery processes. Reliable thermal data for petroleum reservoir rocks are not available and approximate values are generally assumed for reservoir calculations. 'The effects of temperature, pressure and fluid saturation on thermal properties of porous rocks have not been carefully studied. The purpose of the present work was to measure and report the thermal characteristics of some typical porous rocks. A group of eight sedimentary rock samples, including limestone, shale, sandstone and silt-stone, was selected for the study. Properties reported include heat capacities, thermal conductivities and thermal diffusivities. The effect of fluid saturation on these properties was also considered. Determinations of thermal properties require precise measurements which are time consuming and difficult to reduce to a routine basis. Methods have not been developed for measurement of thermal proper-ties under conditions of pressure, temperature, and fluid saturation, which may be encountered in thermal recovery processes. As one approach to these problems, some preliminary work on methods of estimating thermal properties from other more readily measurable characteristics of the rock-fluid system is reported. The samples selected for the studies were oilfield cores from within, or closely associated with oil-productive zones. Descriptions of individual samples are given in Table 1. Clay minerals present in the samples were determined by differential thermal analysis (DTA). Quartz content was estimated from DTA cooling curves. For all but the thermal conductivity tests, a representative 200-gm sample of each core was disaggregated, thoroughly extracted in diox-ane and oven dried at 100°C. The cleaned and dried sample was care- fully split into appropriate portions for the several tests. Chemical analyses of the samples were obtained to permit calculations of heat capacities by methods which are outlined later. Resuits of chenlical analyses are given in Table 2. Heat contents of the test samples were measured by a Runsen-type calorimeter. The heat content of the unknown sample is measured relative to the known heat content of platinum. The apparatus is referred to as a relative error type because of the comparative measurements, and has the advantage of canceling systematic errors. Experimental results are reproducible within 0.5 per cent. A temperature base of 298.16 K is taken for heat content measurements. Measurements were made at five temperatures (260, 440, 620, 800 and 980° F). It was necessary to preheal the sample above the maximum experimental temperature to eliminate volatile constituents. Assuming the weight loss on pre-heat, ing was mostly water, a correction to the observed heat content was made to account for the water originally present in the sample. This latter procedure was followed in the determination of calculated heat contents as will be described later. The apparatus and the method of measure-

By Albert Wiggin

THE copper-bearing sulphide ores from the mines in Butte, Mont., which are for the most part concentrated at the Boston & Montana duction Works in Great Falls and at the Washoe Reduction Works in Anaconda, contain the following minerals of economic value: Chalcocite, Cu2S; enargite, Cu3AsS4; cupriferous pyrite; bornite, Cu3FeS3; covellite, CUS; tetrahedrite, 4 CuS2Sb2S3; and tennantite, Cu8AsS7;. All of the ores carry a high percentage of pyrite. Many of the above sulphides are argentiferous and also carry from 10 to 20 cts. per ton in gold. The gangue is quartz and highly altered granite, with sphalerite and galena and more rarely barite and hubnerite as accessory minerals. An average chemical analysis of the second-class ore concentrated at Great Falls and Anaconda would be as follows: Copper 3.2 to 3.4 per cent. Silver 2. 3 to 3.0 oz. per ton. Gold 0.0-1 to 0.15 oz. per ton. Si02.. 55 to 60 per cent. FeO 12 to 15 per cent.. Sulphur 12 to 1.5 per cent. Al2O3, S to 10 per cent. CaO 0.5 to 0.8 percent. As203, 0.5 to 0.6 percent. Lead 0.2 to 0.3 percent. Before describing the Great Falls flow sleet as installed, at Anaconda, a brief history of the Great Falls concentrator will be given, including a description of the various concentrating machines and systems which have been tested in the search for a flow sheet which would give a higher recovery of copper.

Jan 8, 1913

By Henry D. Hibbard

FoR the purpose of this paper all steels will be divided into two divisions: effervescing and non-effervescing. This classification must be borne in mind as many statements true of one class are not true of the other. Effervescing steels are those that effervesce in the molds, evolving large volumes of gases, which, in escaping, throw up a spray of molten particles of steel and give the molten metal in the mold a rapid stirring or churning motion until it freezes, or, at least, becomes pasty. This effervescing is intended and proper. The non-effervescing steels, which are more or less completely killed, should not evolve any gas in the molds. Many years ago the writer proposed to call the two classes of steels evolution and solution steels, depending on whether the gases in the molds are evolved or kept in solution, but the present designations seem to be better. In America, at least, effervescing steels are in a class by themselves and include steels made for boiler, tank, and ship plates, steel pipe, soft steel wire, wire nails, soft machincry, and structural steels. These are all low-carbon steels with less than 0.40 per cent. carbon. Low-carbon steels that do not effervesce but are killed are also made; these are put into ingots and castings but they are outside the limits of this paper. Effervescing steel is cast into square or slab molds, either top or bottom poured. Most of the effervescing steel is made in the basic open-hearth furnace, though much is made by the acid Bessemer process and a little is made in the acid open-hearth. It is not made by the crucible or electric-furnace process, in which the volume of gas required cannot be produced in the steel and evolved from it in the mold to give the effervescence desired. Any steel ingot, when teeming is finished, is of a certain size or volume. Leaving out of consideration for the moment the lessening of the over-all dimensions of the ingot through contraction due to loss of heat, the ingot may be placed in one of three classes: It may settle, losing in volume; it may stand, that is, remain constant in volume; it may rise, that is, increase in volume. Into which class an ingot will fall depends on the gases of the steel,

Jan 1, 1920

By J. F. Wolff

During the past 4 or 5 years, much has been added to the detailed geologic knowledge of the Mesabi Range. This has not been in the direction of discovery of any new fundamental facts, but of detailed study, subdivision and correlation of different parts of the whole formation and of individual orebodies. Prior to this time, mining engineers in the district were so engaged with the commercial interests of exploring and developing orebodies that close geologic study and subdivision were done in a few instances only. The demand for refinement of work in .this direction has led 'the engineers of the Oliver Iron Mining Co. to do extensive structural subdivision and correlation in all exploration work during the past 4 years. Such work has become a commercial necessity rather than a scientific refinement, and at the present time is being extended to all parts of the Range. In the summer of 1914, the author of this paper wrote a series of articles on the orebodies and special features of the Mesabi Rangc, which was published in the Engineering and Mining Journal, issues of July 17 to Aug. 7,1915. Since that time studies of subdivision of the iron-formation have been extended considerably. The principal feature of this paper is the presentation of the subdivisions of the iron-formation. To this is added a discussion of the relations of the orebodies to the gentle folding and fracturing of the formation, and special features of the Range. The outline will be as follows : I. General geology. 11. Subdivision of Biwabik iron-formation. 111. Relation of orebodies to folding and fracturing of the iron-formation. IV. Special features. Acknowledgnlent is due to W. J. Olcott, President, and John Uno Sebenius, General Mining Engineer, of the Oliver Iron Mining Co., for permission to use the information presented in this paper.

Jan 1, 1917