Search Documents

By Walter Rose

Experimentation which measures differences in pressure across the interfaces of immiscible fluids in the interstitial spaces of porous media may be termed "capillary pressure experimentation". In the literature of petroleum technology since 1941 there have appeared twelve papers popularizing capillary pressure concepts and developing applications of these concepts for the solution of problems of practical reservoir engineering importance, such as the determination of connate water, fluid distribution. in transition zones, reservoir rock textural properties, and oil recovery from petroleum reservoirs. Although a review of the literature would be justified at this time in order to reconcile the conflicting viewpoints which are contained in the cited papers, the object of this note will be of more limited scope. It is believed that the recent paper of Muskat alls sufficient attention to many of the uncertainties which arise upon examination of the published literature. such that until satisfactory counter-proposals can be made it will serve our purpose only to mention some other like uncertainties. This will emphasize further the need confronting petroleum technologists to re. consider and reformulate the application possibilities of capillary pressure experimentation. In particular, I sug- gest that we examine the thesis that capillary pressure experimentation as above defined can lead to measurements reflecting the recovery of oil from petroleum reservoirs, as was proposed first" by Amyx and Yuster and was first reduced to practice by the experimentation of Welge . In fact. I shall deal exclusively with the Welge papers since it is the principle one on this subject which has appeared to date. I shall attempt to show that the possibility of describing oil recovery features in terms of capillary pressure phenomena has not been established entirely. The Welge paper was a pioneering effort to evaluate this recovery application possibility. P. P. Reichertz' comments on the Welge paper state that non-wetting phase discontinuities are developed occasionally in the Welge experiment, and restate Muskat's argument that discontinuous fluid elements (partially saturating the interstices of porous media which are elsewhere saturated with some other immiscible phase or phases) are not subject to the requirements of hydrostatic equilibrium. It is the purpose of my comment to show that it is unnecessary to make Reichertz' postulation regarding non-wetting phase discontinuities (however valid) when it is desired to criticize Welge's theoretical treatment of his problem. It can be shown that Welge's method of measuring values for ''capillary pressure" is invalid in many instances of application, such that his reported curves of capillary pressure Versus fluid saturation often have no physical meaning, even throughout the interval of fluid saturation where it might be otherwise suspected that no phase discontinuities occur. By considering established principles of capillary pressure experimentation it can be shown that the pressure difference experimentally observed between wetting and non-wetting fluid phases which are contained in external reservoirs will reflect on the capillary pressure difference at the interfaces of contact between these phases only when the following conditions are satisfied: (a) There shall be a balance between the opposing forces of gravity and capillarity, as obtains under conditions of hydrostatic equilibrium when the positions of the interfaces of contact become fixed in pore spaces of certain geometry (b) The wetting and non-wetting fluids within the interstitial spaces shall everywhere be continuous with the external wetting phase reservoir and the external non-wetting phase reservoir, respectively. It will become apparent immediately that in any instance when a greater pressure is recorded in the external wetting phase reservoir than in the external non-wetting phase reservoir, one may establish either that static equilibrium has not been attained or that discontinuities in one or more of the fluids have been developed. This is because the pressure otherwiee is always gereatest in the non-wetting phase at each static interstitial interface of contact with the wetting phase. such that the externally measured pressure in the non-wetting phase likewise must be greatest if the above conditions are to be satisfied.

Jan 1, 1949

By F. du Breuil, R. L. Mundell

Longwall methods to mine coal in the United States provide the potential advantages of greatly increased productivity, improved safety, and a higher percent recovery. However, use of longwall systems during the past 10 years has increased much more slowly than was anticipated. This paper discusses some of the problems inhibiting the increased use of longwall systems and a proposed research program to address one of the most critical problem areas.

Jan 1, 1981

By R. Bakish, W. D. Robertson

IN the course of a study of stress corrosion cracking of AuCu,, it was necessary to develop new electropolishing and metallographic etching methods. The techniques are generally useful for Cu-Au alloys, including the AuCu composition in which transformation markings are well delineated. For electropolishing, the only satisfactory electrolyte and procedure that has been found1 has the composition given in Table I. The solution must be vigorously stirred while polishing and the temperature maintained in the range of 55" to 62°C. The electrolyte is very unstable and can be used only for 10 to 15 min after which its color changes and a dark-brown precipitate forms. The polishing time is between 1 and 4 min depending on the initial surface preparation. The use of a hood is recommended to avoid the danger of cyanide gas which may form at one of the electrodes even though the solution is alkaline. The optimum current and voltage conditions for vertical anode and platinum cathode are on the plateau shown in Fig. 1, in which voltage is measured across the cell terminals. At voltages below the plateau, etching of grain boundaries occurs and under some conditions, which have not been clearly defined, octahedral etch figures are observed. For general purpose grain-size determination in polycrystalline alloys, a 3 pct solution of iodine in methyl alcohol is used with excellent results. However, when it is necessary to reveal small orientation differences or concentration gradients in an alloy, the iodine etch is not satisfactory. For this purpose, a highly satisfactory etching procedure was developed during this investigation. It involves the use of the vapor given off by freshly prepared aqua regia. The solution employed is 3HC1 to lHNO, which decomposes in accordance with the reaction HNO, + 3HC1 = NOCl + 2H,O + Cl,. The polished specimen surface is held about 1 to 2 cm above an aqua regia solution for 2 to 10 sec depending on the intensity of the contrast required and the surface is not subsequently washed. The results obtained with a coarse grained cast structure are shown in Fig. 2. Subgrain boundaries in a single crystal and concentration gradients within the boundaries are developed by the same treatment with the results shown in Fig. 3. Obviously, any conclusions regarding structure-dependent properties will be modified by the pronounced heterogeneity, which is not clearly evident when more conventional methods are used. Interesting structural details are also revealed by treatment for 4 hr at 850°C in unpurified tank argon. Fig. 4 shows a pattern characteristic of orientation-dependent oxidation.

Jan 1, 1956

No. 484.-A mining engineer and geologist of long and varied experience in North and South America is open for an engagement. Exploration and development work preferred. Rare minerals a specialty. No. 485.-Member, mining engineer, technical graduate, married, age 28, exempt, with 9 years experience at gold and silver, copper, lead, and coal mines, 4 years with present employers, is open for engagement as mine superintendent or foreman, or in charge of cyanide plant. Boston or New York interview after Oct. 10. Present position, day foreman at producing gold-silver mine in Montana. References. No. 486.-Member, age 34, married, varied experience in iron, copper, nickel, talc, etc., principally as surveyor, mine and surface geologist, and superintendent of explorations, is open for engagement. Preference, connection with some eastern consulting engineer or firm of engineers. No. 487.-Member, mine superintendent, 18 years' experience in the West and in the Lake Superior districts. Thorough business and technical training. Personal interview, preferably Chicago.

Jan 10, 1918

By Bernard York, John J. Reed

J. P. Zannaras (U.S. Tungsten Corp., Congress, Ariz.) —In the investigation described in the paper by Bernard York and John J. Reed, the 8x8x8-in. square block was subjected to compressive forces from three sides, top, side, and rear. Let us refer to the stresses set up by these forces as Sz due to top pressure, Sy due to side pressure, and Sx due to rear pressure. At the section across the 2-in. hole (when failure occurred at 317 psi) the compressive stress Sy was equal to 317 x 8/6 = —422 psi, the top compressive stress S; is of the same intensity, —422 psi, and the rear compressive stress S, equals —317 psi. The true stress is T = Sy — S — S Taking as 0.2,* Taking the case when the opening was ½ in. and failure occurred at 517 psi, 8 Sy - 517 x -----= —537 psi 7.5 8 Sz = 517 x-----= —537 psi 7.5 Sx = —517 psi The true stress T = Sy — Sz — S, T - —537 + 0.2 x 537 + 0.2 x 517 = —327 psi. It can be shown that the above fundamental formula holds good not only for the above two examples but for all sizes of openings used, because when this formula is expressed in terms of the external pressure and size of the opening it agrees perfectly with the experimental results obtained by the authors and given in Fig. 12 of their paper. General formula: T = Sy — s: — S....

Jan 1, 1955

By John S. Brown

AT opposite ends of a mineralized belt of northeast-southwest trend, and ten miles apart, are the Edwards and Balmat zinc minas, in St. Lawrence County, New York, west of the Adirondacks. The principal town is Gouverneur, fifteen miles west of Edwards, eight miles northwest of Balmat, and the area is often referred to as the Gouverneur district. (See Fig. 1.) At various times the district has been noted for its hematite mines, pyrite mines, and marble quarries, all now abandoned. At present, in addition to zinc, it is the country's largest source of industrial talc. A short distance to the east important magnetite mines are operating. Geologically the district lies at the southern margin of the Canadian shield, where this great expanse of Pre-Cambrian igneous and metamorphic rocks merges into the foothills of the Adirondacks. The rock formations in approximate order of areal extent and importance are as follows:

Jan 1, 1947

By Philip S. Mathews

THE tremendous stimulus given to the mining industry by the gold and silver policy of the present administration has found the capital market for mines ill prepared to afford practical means of financing. Particularly has this been true of the host of abandoned high-cost producers and prospects which increased gold and silver prices have made potentially profitable. In a comparatively short time, experience has demonstrated abundantly that valuable properties have frequently failed to secure capital, while questionable properties have drawn to themselves and their promoters more of the public moneys than their prospects justify. Singularly enough the fault is usually attributable to faulty financing. Discussion and study of this problem are vital to the industry.

Jan 1, 1936

By D. J. McAdam

As shown in three recent papers by the author,6,7,8 in two papers by McAdam and Mebs,9,10 and in a paper by McAdam, Mebs, and Geil,11 the technical cohesive strength of a metal, in any particular state as regards mechanical treatment and heat-treatment, cannot be represented by a single stress value, but must be represented by a diagram with the principal stresses? as coordinates. Each point on the boundary of such a diagram represents a technical cohesion limit. The technical cohesive strength thus comprises an infinite number of technical cohesion limits, each representing fracture under a specific stress combination. Moreover, neither the yield strengths nor the ultimate strength can be represented completely by a single stress value, but must be represented by a diagram with the principal stresses as coordinates. All combinations of the principal stresses may be classified in three groups as illustrated by Fig. I. Fig. Ia shows three typical stress combinations with no two principal stresses equal. The magnitude of each principal stress is indicated qualitatively by the length of the arrow. Arrows pointing away from the cube indicate tensile stresses; arrows pointing toward the cube indicate compressive stresses. Typical stress combinations with two principal stresses equal are illustrated in Figs. Ib and Ic. Such stress combinations would be produced by subjecting a cylinder to combinations of uniform axial and radial stresses. The uniform radial stress may be resolved into two equal principal stresses, with the mutually perpendicular directions rotatable around the axis of the cylinder. Fig. Ib shows stress combinations with S2 equal to Sa. The greatest principal stress is in the axial direction, and the stress combination tends to cause either absolute or relative increase in length.* Fig. Ia shows stress combinations with Ss equal to Sl. The greatest principal stress is in the radial direction, and the combination tends to cause either absolute or relative decrease in length. The complete representation of either technical cohesive strength, yield strength, or ultimate strength generally requires a three-dimensional diagram. When two of the principal stresses are kept equal, however, the strength of a metal may be represented by a two-dimensional diagram with the coordinates representing the axial and radial stresses.6-11 In this paper, attention will be confined almost entirely to stress combinations with two of the prin-

Jan 1, 1944

By J. S. Vanick

AN extremely hard, tough, and strong, white or chilled cast iron has been applied for the past several years to industrial and mining services in which its unusual properties have been confirmed by its ability to deliver in many instances much better performance than plain chilled iron, or other wear-resistant materials. It is being produced regularly by alloying a good base composition of chilled or white cast iron with essentially 4 to 6 per cent of nickel and 1 to 2.5 per cent of chromium. Such a material can attain a hardness exceeding 600 to 750 Brinell as against 380 to 530 for corresponding grades of plain chilled iron. The strength is approximately doubled and the toughness significantly increased. These properties make it especially useful for many applica-tions requiring a high hardness for resistance to wear, abrasion, attrition, deformation; to some extent to high compressive loading and to a lesser but important degree to corrosive action. A wide variety of commercial castings is being successfully produced from this iron, ranging in size from the small-grain grinding plates or burrs through medium-sized castings such as sand pumps up to large, heavy castings such as rolls for metal rolling or cement grinding. The composition of this white cast iron may be roughly bracketed within the range shown in Table 1.

Jan 1, 1933

By Y. C. Liu, G. A. Alers

measurements of the anisotropy in Young's modulus produced in copper by rolling 95 pct reduction in thickness below room temperature have been carried out in order to study the dependence of the texture on rolling temperature. The results clearly show the transition from a copper-type texture to a brass-type texture as the temperature of rolling is lowered. The intermediate textures observed can be described very well as a simple mixture of the two terminal textures. These results cormbined with other texture measurements make possible afresh review of the experimental facts velating to rolling textures in fee metals and, as a consequence, a critical examination of the current theories is presented. PREVIOUS experiments have shown that the transition from the copper- to the brass-type rolling texture is clearly displayed and can be quantitatively analyzed by measurements of the anisotropy of Young's modulus.' Application of this method to the Cu-Zn alloy system showed that the description of the texture transition as a gradual rotation of the grains from the orientation characteristic of the copper texture to the {110}(112) texture of brass2 was inconsistent with the data. Instead, the data suggested that the texture within the transition region could be described as a simple mixture of the two terminal textures.5 Unfortunately, it was difficult to establish this point conclusively because of the inadequacy of corrections for the composition dependence of the single-crystal elastic constants. Since a rigorous establishment of the nature of this texture transition is essential to our understanding of the formation of rolling textures in fee metals, it is clearly important to undertake an investigation in which the composition dependence of the elastic constants would not enter. A suitable composition-independent texture transition is provided by the well-established variation in the rolling texture of copper with rolling temperature. This temperature-dependent texture transformation has been studied by smallman' in several fee alloys and by Müller5 and others"' in copper. They observed that the texture characteristic of copper rolled at room temperature changed to a brass-type texture when the rolling temperature was lowered to 77°K. Although it is not possible to decide unequivocally from the published pole figures whether or not the 77°K rolling texture of copper is entirely of the brass type,' this complication does not affect the main purpose of the present investigation. In addition to establishing the nature of the texture within the transition region, the modulus data should also provide a determination of the temperature at which the transition occurs as well as the temperature range over which the transition extends. This information when combined with the modulus data on Cu-Zn alloys would then provide a considerable body of new information on textures in fee metals. Since these modulus results and the data obtained from pole-figure studies must be internally consistent, it is appropriate to compile a brief summary of the experimental observations based on all available methods rather than on the pole-figure data alone as has been done in the past. The primary purpose of such a summary would be to yield a more precise definition of the experimental facts on the rolling textures of fee metals, and thus greatly facilitate our evaluation of various proposed theories in this field. The final section of this paper is devoted to this compilation of consistent, experimental facts and their application to the various theories. EXPERIMENTAL PROCEDURE Two 18-lb ingots of cathode copper of 99.99 pct purity were induction-melted under a nitrogen atmosphere in a graphite crucible and chill-cast into a steel mold. The ingots were repeatedly cold-rolled and annealed (I hr at 500°C) into slabs about 1 1/8 in. thick. Blocks 3 1/4 in. wide, 2 1/4 in. long, and 1.000 in. thick were machined from each slab. The rolling schedule used was the same as in the previous investigation1 and the final thickness of the sheet was 0.050 in. with a rolling reduction of thickness of 95 pct instead of 97.5 pct as in the previous work.' The compositions and temperatures of the cold baths used for the low-temperature rolling were as shown in Table I. After each pass the rolled strip was immediately immersed in the cold bath for about 1 min or until the bubbling of the bath had subsided. The modulus data were taken within 2 hr after the rolled strip was warmed to room temperature for the first time, so that effects due to recrystallization were minimized. The modulus specimens were in the shape of flat bars, 3 in. long, 4 in. wide, and 0.050 in. thick, cut with their long dimensions oriented at 15-deg intervals between the rolling direction and the transverse direction. The values of Young's modulus were deduced from measurements of the frequency at which these long narrow bars were set into longitudinal, resonant vibration as previously described.9 To excite the mechanical vibrations in the specimen, an electromagnetic drive similar to that employed by Thompson and lass" was used. The maximum in the amplitude of

Jan 1, 1968

By B. Wilshire, W. J. Evans

The high-temperature creep properties of nickel, zinc, and iron have been determined over a range of stresses. The creep strain, E, was found to vary with time, t, as: where e0 is the instantaneous strain on loading, ET the total transient creep strain, $ the steady creep rate, and m is a constant relating to the rate of exhaustion of transient creep. Deviations from this relationship occurred during the initial 10 to 15 pct of the transient stage. These deviations result in the initial creep rate, go, calculated as (m . ET + es), being considerably lower than those obtained by measurements on the creep curve. For all materials, the initial creep rate, the constant m, and the duration of transient creep are all related to the steady creep rate. These relationships suggest that transient and steady-state creep should not be regarded as distinct stages.

Jan 1, 1969

By P. Somasundaran, D. R. Nagaraj

Based on our finding that commercial copper chelating solvent extractants such as LIX65NR and LIX63R are excellent collectors for copper minerals, a detailed study was made using several water-soluble chelating agents belonging to the class of aromatic hydroxyoximes and having a gradual structural variation. A basic study of the system salicylaldoximetenorite was also carried out. Microflotation tests as a function of concentration of oxime, pH, addition of copper, etc., using oxidic copper minerals such as chrysocolla and tenorite, and batch laboratory flotation tests using synthetic mixtures of quartz and oxidic copper minerals were carried out. The results have demonstrated that the hydroxyoximes studied have comparable collector property, and in all cases the oxime was found to be partitioned between the mineral surface and the copper in the bulk aqueous phase in the form of a bulk copper chelate. The occurrence of the latter could be accounted for by formation in the bulk phase of a chelate between oxime and copper released from the mineral and/or by the detachment of the surface chelate. The role of surface and bulk chelates in flotation is discussed based on the results of partitioning of chelating agent into bulk and surface chelates in the salicylaldoxime-tenorite system. The effect of structural aspects such as isomerism and substitution in the molecule on the collector property of the oximes is also discussed. Substitution on oximic carbon by alkyl groups is found to promote collector activity. Only the anti-isomer has the ability to collect.

Jan 1, 1982

By John F. Blandy

IT is not my intention in this article to consider this subject in the light of the geographer or geologist, but rather in that of the mining engineer, and to endeavor to show the necessity and value to him of studying the minor details of the field or district in which he may be engaged. I t has been said by a distinguished geologist that "the natural boundaries of the geographer are rarely described by right lines. Whenever they occur, however, the geologist may look for something remarkable." And again : " Physiognomy is no idle or doubtful science in connection with geology. The physiognomy of a country indicates almost invariably its geological character." Our country furnishes examples enough of the truth of these remarks, and in no part of it is it so beautifully illustrated as in our own State, which has been so ably described by Prof. Lesley in his admirable little work on the "Topography of Coal." As the great mountain lines become guides to the geologist in determining and mapping out the geography of the formations, so do the minor details of topography become guides to the mining engineer in conducting his explorations, discovering of dislocations, and determining the character of the deposits which are the object of his search. I t is therefore requisite that he should, whilst making his surveys, pay the strictest attention to every variation of the landscape and surface of the ground. Until he has mapped out every feature he may be unable to read the geological changes which may have

By Sherwin Kelly

THE need for geophysicists to adopt a uniform mode of expressing the electrical resistivity of geological formations has been stressed by Dr. A. S. Eve.1 The present paper is to emphasize the point he raised, to bring the weight of disinterested authority to bear on the matter, and to urge the adoption henceforth, save in exceptional cases, of a standard expression for resistivity; all in the hope that the needed reform will thus actually be brought about. The general definition of the resistivity of a material is the resistance in ohms between two opposite faces of a unit cube of that, material. No account need be taken here of the cases in which the unit volume is not a cube, and the units of length and cross-section are different, encountered principally when dealing with metallic conductors such as wires. The idea of the resistance of a unit volume of earth or rock has found expres-sion in geophysical literature in a number of forms and with a variety of units. Fortunately, the metric system has been adhered to in most cases, so ordinarily the meter or the centimeter, usually the latter, has been the measure chosen. The resistivity is then the resistance of a cube of the given rock, or soil, one centimeter on, an edge. This is far from always being the same thing, however, as the resistance of a cubic centimeter. A long thin wire could contain a cubic centimeter and have a high resistance, whereas the same volume formed into a flat plate would have an entirely different, and quite low, resistance between faces. Con-sequently, it is not proper to express resistivity in ohms per cubic centi-meter, inch, etc., as has been done occasionally by .some writers. In an effort to emphasize the idea of cubic volume, some geophysicists, the writer among them, have used the phrase, ohms per centimeter cubed. This is a graphic way of picturing the measure, but is not in favor among highly qualified authorities. In this connection, an appeal was made to the U. S. Bureau of Standards for advice, and the Director, George K. Burgess, kindly replied in detail as to the practice adopted by his Bureau: ." . .' such expressions as ohms per centimeter cubed' or any similar expressions are objectionable, because they certainly carry the implica-tion that the resistivity is found by dividing ohms resistance by the volume in cubic centimeters." Actually, of course, resistivity is found

Jan 1, 1932

By J. Gordon Parr, M. J. Bibby

In addition to the (bcc) - (cph) transformation at 882°C a second distinct change of slope has been observed on a titanium cooling curve between 905" and 960°C.1,4 Duwez,1 commenting on work by McQuillan,2-4 attributed this arrest to contamination of the specimen with oxygen—a possibility that existed even at the reduced pressure of 10-5 mm Hg at which the experiments were conducted.

Jan 1, 1963

By Charles F. Hickey, Eric B. Kula

Thermomechanical treatments applied to the maraging steels include a) cold working in the austenitic condition at 650°F, followed by transformation to martensite and aging, b) cold working in the murtensitic condition and aging, and c) cold working in the aged condition with and without subsequent reaging. The strength increases in these steels are very small compared to the increases observed in conventional carbon and alloy steels. The changes that are observed are compatible with the strengthening mechanisms operative during thermomechanical treatment of conventional steels, however. Differences are caused by the absence of a carbide precipitate and the low work-hardening rate in both the solution-treated and the aged conditions. ThE 18 pct Ni maraging steels represent a class of steels which are finding great interest for high-strength applications.1~2 They are essentially carbon-free, and contain 7 to 9 pct Co, 3 to 5 pct Mo, and 0.2 to 0.8 pct Ti. Although austenitic at elevated temperatures, they can be air-cooled to room temperature to form a martensite, which because of the absence of carbon is relatively soft. On subsequent reheating age hardening occurs and strength levels of 250 to 300 ksi yield strength can be attained. These steels appear to be particularly suitable for studying the response to various thermome-chanical treatments for additional reasons other than the obvious one of attempting to improve their already attractive properties. Thermomechanical treatments can be defined as treatments whereby plastic deformation, generally below the recrystal-lization temperature, is introduced into the heat-treatment cycle of a steel in order to improve the properties. With an absence of intermediate transformation products on air cooling the maraging steels have good hardenability and hence can readily be cold-worked in the austenitic condition prior to transformation to martensite. Further, they can be worked in the martensitic condition prior to aging, and even can be deformed in the fully aged condition. Finally, it is of interest to compare their re- sponse to that of the more conventional alloy and carbon steels, where the role of carbides is important in the strength increase by thermomechani-cal treatments. The thermomechanical treatment of conventional steels has been the subject of a recent review.' I) MATERIALS AND PROCEDURE The steel used in this investigation was a commercially produced vacuum-melt heat, which had been rolled to 0.090 in. and mill-annealed. The composition of the alloy was as follows: 0.02 C, 0.08 Mn, 0.10 Si, 0.009 P, 0.009 S, 18.96 Ni, 7.34 Co, 5.04 Mo, 0.29 Ti, 0.05 Al, 0.004 B, 0.01 Zr, and 0.05 Ca. Unless otherwise stated the heat treatments used were the standai-d solution treatment at 1500°F for 1 hr, air cool, followed by a 900°F, 3 hr age. In this condition, the material exhibited 232 ksi yield strength and 239 ksi tensile strength. Mechanical properties were determined by Vicker's hardness measurement (20 kg) and by tensile tests on standard 1/2-in.-wide, 2-in.-gage-length sheet tensile specimens. Notch tensile tests were run using the 1-in.-wide NASA type, edge-notched specimen.4 Fracture-toughness determinations were made on 3-in.-wide, center-notched, fatigue-cracked specimens, following the recommendations of the ASTM Committee on Fracture-Toughness Testing.4 An electric-potential technique was used for measuring the crack size at the onset of rapid crack propagation5 which is necessary for calculations of Kc, the critical stress-intensity factor under plane-stress conditions. The critical stress-intensity factor under plane-strain conditions KI, was also calculated, using the stress at which the first observable crack growth occurred. 11) RESULTS A) Cold-Worked in the Austenitic Condition. The reported M, temperature for the 18 pct Ni maraging steel is about 310°F.1 Therefore, a temperature of 650°F was selected as suitable for rolling in the austenitic condition. Specimens were solution-treated at 1500°F for 1 hr, air-cooled to 650°F, and rolled varying percentages from 0 to 60 pct, at 20 pct reduction per pass. Tensile and hardness properties after aging at 900°F for 3 hr are shown in Fig. 1. The tensile strength increases from 253 to 271 ksi and the yield strength from 247 to 265 ksi as a result of a reduc-

Jan 1, 1964

By S. Norton, S. LeFevre

In the West, capitalists have expended many millions of dollars developing the low-grade porphyry ores of copper. Half a dozen of these great enterprises have proved to be wonderful commercial successes. They have demanded improved crushing and concentrating machinery and consequently it has been developed. Many improved methods, cheap power, superior business organization, all these have contributed to this success, but the main feature is the handling of the material in enormous quantities, on a manufacturing scale. The mining chance of "striking it rich" has been eliminated by the manufacturing certainty of handling large quantities of material of known value, which while of relatively low grade, is available in large tonnages, assuring a supply for many years' run of the mill. Then the returns on the money invested are sure. The concentration of low-grade magnetic iron ores, separating the magnetite crystals from the gangue by the use of magnets, is a field of work in which the lessons taught by the development of the porphyry coppers can be studied to advantage. Large-scale operations, and the liberal expenditure of enough money at the start to insure the most economical operations, are the means of securing the desired results. The problem is to utilize millions of tons, and we may safely say billions of tons, of now worthless iron-bearing rock and to produce from it 10,000,000 to 20,000,000 tons per year of high-grade ore carrying 60 per cent. iron or higher; to take the lean material as found in nature, varying widely in iron content, and bring it up to a uniform standard of shipping ore. At present these ores are mined carrying from 25 to 50 per cent, iron, and the shipping product is brought up to 60 or 65 per cent. Fe. If future economies of operation make it possible to extend this process so that 15 per cent. iron in the crude ore can be treated as a commercial success, the additional tonnage available will be enormous. A 15 per cent. Fe crude ore raised to 60 per cent. Fe concentrate with 5 per cent.

Jan 1, 1917

By Gilbert H. Cady

Extensive sampling of coal in Illinois during the past 10 or 12 yegrs by the State Geological Survey, in cooperation with various organizations, such as the U. S. Bureau of Mines, the University of Illinois, and the Illinois Cooperative Mining Investigations, has made possible the delineation of two areas of low-sulfur coal in the southern part of Illinois. The $fur content is less than 1.25 per cent., so that, if otherwise suitable, these coals can be employed for metallurgical uses and for the manufacture of water-gas and retort gas. One of these areas is small and lies in Jackson County, near Murphysboro, the other is much larger and includes a large part of the famous Franklin County field. A small area of No. 2, or Murphysboro, coal has been worked for many years near the town of Murphysboro, Jackson County, Ill. In two mines, at least, the coal has a sulfur content of less than 1.25 per cent. It is doubtful, however, whether this field will ever be a source of large tonnage as the total area underlain by low-sulfur coal in workable thickness is probably less than 15 sq. mi. (24.14 sq. km.), and a large part of it has already been worked out.. The location of the area of low-sulfur coal in the Franklin County field is shown in the accompanying map. The small area underlain by the Murphysboro low-sulfur coal is shown near the town of that name in the central part of Jackson County. The larger area lies in the west side of Franklin County, extending also about 6 mi. (9.65 km.) south into Williamson County, about 4 mi. (6.43 km.) west into northern Jackson and western Perry County, and northward an undetermined distance into Jefferson County. All but the northern limit of the area is fairly well defined by sampling in numerous mines. The inner cross-lined area is underlain by coal having less than 1 per cent. sulfur, the outer boundary surrounding the area underlain by coal having less than 1.25 per cent. sulfur. The coal mined in the district is No. 6 or Herrin coal, commonly known as the Carterville or Franklin County coal. The bed has a thickness varying from about 8 ft. (2.4 m.) on the border of the low-sulfur area up to more than 10 ft. (3 m.) in the central portion, locally having a thick-

Jan 1, 1920

By J. F. K. Brown

ANTHRACITE in 1943, in common with the coal industry as a whole, passed through a year of wage negotiations that seemed endless. In the early months discussion of the United Mine Workers' demands was taken up and carried on continuously until May, finally reaching an impasse when the Union refused to continue at work, while submitting their demands to the War Labor Board. Thus a strike threatened, averted by the Federal Government taking over the industry, effective May 1, by order of the President. An office of the Bureau of Mines was established in Wilkes-Barre under the direction of J. J. Forbes, Mineral Production Security Division, as regional manager, who conducted operations until September, 1943, when the collieries were turned back to the operators. But the miners did not agree with the War Labor Board's award rendered in the fall, resulting in a recurrence of the previously threatened strike. again averted by Government control. In addition to the major upsets, a number of individual suspensions occurred at various mines. In spite of these drawbacks, to which might be added the difficulty of obtaining equipment and the scarcity of man power, the industry by November was only little less than a million tons short of the previous year. and in all probability, finally produced but little less than in 1942. This little less. however, was greatly missed in the market.

Jan 1, 1944

By John Chipman, Daniel Dutilloy

The equilibrium of gaseolis H2O-H2 mixtures with liquid iron-phosphorus alloys in the range 0 to 3 pct P is used to establish the increuse of the activity coefficient of oxygen, in the presence of phosphorus. Two different sampling techniques are used. THE importance of oxygen as a refining agent in steelmaking operations makes it desirable to improve our understanding of its behavior. Phosphorus which is always present in the ores has adverse effects on steel properties and its removal is necessary. The present study was undertaken to evaluate the interaction of oxygen and phosphorus in molten iron. Bookey, Richardson, and welch1 have studied the phosphorus-oxygen equilibria in liquid iron in the presence of lime. They used a mixture of hydrogen and water vapor to control the oxygen potential and worked with crucibles made of tetracalcium phosphate and lime. At low phosphorus concentration, i.e., at high oxygen, they observed a marked deviation in their results. They tentatively ascribed this to a large negative effect of oxygen on the activity of phosphorus. This was then included by chipman2 in his review of interactions in liquid iron. Pearson and Turkdogan 3 have later reported an interaction parameter They equilibrated a mixture of hydrogen and water vapor with an iron-phosphorus alloy contained in an alumina crucible and sampled the melt by suction in a silica tube. The solubility of oxygen in iron-phosphorus alloys has been studied by Levenets and Samarin.4 They reported an interaction parameter

Jan 1, 1961