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By Donald Gilbert

PRIOR to July, 1919, the sampler at each mine of the Anaconda Copper Mining Co. in Butte did his work in his own way and was responsible to the mine foreman only. At that time, the sampling at all the company's Butte mines was placed in charge of a member of the geological department and stand-ardized methods of doing the work, were adopted. These standards were incorporated in a set of instruc-tions accompanied by blueprints representing typical conditions. The main features of the instructions were as follows: All samples to be cut at breast height and horizontally, regardless of dip of vein, and the horizontal width reported. A single sample to include not more than a 5-ft. width of the breast and to weigh not less than 4 lb. for this width. Where the vein is made up of two or more streaks of different hardness or mineral content, each streak is to be sampled sepa-rately and the average value of the combined width figured. If two streaks of ore are separated by a streak of waste, which is not sampled, in obtaining the average value of the breast the waste must be figured in with a zero assay. Drifts to be sampled in the breast after each round. Raises to be sampled for each floor raised. Each end to be sampled separately and the average width and value of the two ends to be used as the average of the floor. All veins cross-cut to be sampled along the side of the cross-cut, at breast height and horizontally. Where the vein strikes at an acute angle to the line of the cross-cut, the width of sample must be corrected to show the horizontal width at right angles to the line of strike of the vein. Rill stopes must be sampled across the full mining width. In square-set stopes, each set must be sampled separately along the line of the caps. Waste portions of the vein which are mined for filling must not be included in the sample.

Jan 2, 1922

By W. J. McKenna

THE International Smelting Co. concentrator at Tooele, Utah, first operated on a custom basis for the treatment of lead-zinc-iron ores on Nov.' 1, 1924, with a capacity of 500 tons per day. On May 1, 1925, the capacity was increased to 1000 tons per day by the addition of another 500-ton section. The concentrator has since operated on the two-section basis, each treating 500 tons per day entirely by flotation. LABORATORY AND TEST MILL In connection with the concentrator, a well-equipped laboratory and small continuous testing plant are maintained. The flotation equipment in the test plant is of both the Callow and Mineral Separations Sub-"A" types, so that actual concentrator conditions may be duplicated as closely as possible. PURCHASING OF ORE A new shipper usually sends to the plant a 25 to 50-lb. sample, representative of the ore to be shipped. Batch flotation tests are made on this sample to determine its amenability to the concentrator treatment flowsheet and reagent combinations. The results of these tests, which are accurately correlated with those obtained at the concentrator, both as to grades of products and recoveries, determine the actual value of the ore as submitted in the ore purchasing department's treatment schedule. Hearty cooperation has existed at all times between the ore purchasing and operating departments in the selection of ores as concentrator feed. ORE TREATED The basic tonnages for mixtures on the two sections come from the Park City and Bingham mining districts. The Park City tonnages are received by rail and consist of crude ores and gravity mill products. Those from the Bingham district are received by rail and aerial tramway,

Jan 1, 1928

By Edwin Ludlow

IN CONSIDERING the waste in the coal industry, which is the title of this discussion, we must entirely eliminate the anthracite region. The demand for anthracite has been constantly increasing and the mines have been able to run during this last year, while the bituminous field was idle for two-thirds of the time. It is on a 100 per cent. basis, which is the best answer to any waste in industry investigations. The anthracite region is also in a very much better position on account of its control by very large companies which realize that their resources are limited; they must husband these resources in every way and they are making the most careful study of methods of mining and preparation to avoid any possibility of waste. This is well known and realized by the managers of those companies. Even the fine slush which was formerly thrown away is now being stored in the hope that methods will be found by which it can be used economically, either in briquet or pulverized fuel in coking. This has been tried. The anthracite factor may be dismissed from the waste in industry discussion, except as it applies to the general public that burns anthracite; there is a tremen-dous waste of anthracite in the burning of it. Looking at the ash piles where anthracite is burned and seeing the amount of carbon that comes away with the ashes, one realizes that proper efficiency is not obtained in the burning of that coal. Even its higher cost does not seem to bring people to a realization of the necessity of conserving and burning properly the entire coal carbon content of what has cost so large a price. Many people feel that they want to have the coal as large as they can shovel into the furnace; they do not realize that the small coal makes just as many heat units and can be bought at half the price. Consequently, the demand is continually in excess of the probable pro-duction for the larger sizes of anthracite, while the smaller sizes, such as large buckwheat and pea, are a drug on the market and can be bought at nearly half the figure; and yet, if properly burned, these produce just as much heat and can be used with a much greater economy than the large egg and stove.

Jan 3, 1922

By Georges Millot

USUALLY the search for clays is left to chance in unexplored areas. A local working by the inhabitants or an outcrop is often the only guide. If the conditions of genesis of clays were always known, a set of general rules could be drawn up that would apply to this search. For example, a certain type of clay might be found wherever the sediment indicated a favorable environment. This paper sums up the considerable amount of knowledge that has been accumulated about the genesis of sedimentary days and offers some rules to be observed in prospecting for new clays. ANALYTICAL STUDY OF SEDIMENTARY CLAYS Clays may be found in many formations, both recent and ancient. All the intermediums exist between the deep-sea deposit and the mud deposited by a stream. In order to find out whether the nature of clay deposits depends on the environments in which they were formed, the samples used in the investigation described herein were very carefully chosen from: (1) ancient sedimentary series (a few from recent ones), (2) zones where conditions of genesis are typical. Ancient Formations Ancient formations were chosen because they are less difficult to sample than the bottom sediments of present-day lakes and seas. Moreover, a geo- logical section makes it possible to define the conditions of genesis of a deposit based on its facies, fossils, stratigraphic relations, and paleography. A present-day deposit is defined only by its aspect at the moment. Its previous history may have caused mixtures, alterations, and changes of environment, which escape detection. Typical Conditions of Genesis Samples from ancient deposits were taken from zones where typical conditions of genesis prevailed. Only clays from marine, lagoonal, and lacustrine environs are concerned in this study because the nature of the original en- vironments could be affirmed. In this way an inventory of the nature of sedimentary clays has been made for rocks formed in typical and individual environments; therefore the extent of the results that may be drawn from such a study will need discussion.

Jan 1, 1952

Discovery of a hitherto unsuspected extension of the Vermilion range iron formation in Northern St. Louis County, Minn., has been announced by the director of the State's geological survey, Dr. George M. Schwartz. USGS aeromagnetic maps show that the Vermilion range curves southeast from the Tower-Soudan area into the wilderness between Embarrass and Bear Head Lake. Dr. Schwartz believes that this new information justifies considerable exploration and drilling for iron ore in an area of about 20 sq miles southeast of Soudan. The aerial maps were a result of a three year USGS-Minnesota Geological Survey aerial search for iron formations in a 30,000 sq mile area in northern Minnesota.

Jan 12, 1950

George Smith, Sydney, N. S. Wales (communication to the Secretary): The very interesting paper by Mr. Emmons on " The Secondary Enrichment of Ore-Deposits " has just come under my notice; and its reference to my own paper* on " The OreDeposits of the Australian Broken Hill Consols Mine "† is therefore only noted some two and a half years after its publi-

Jan 1, 1903

By AIME AIME

CHARLES WASHINGTON MERRILL, the second to be honored by the award of the James Douglas gold medal, throughout his entire professional career has been identified with the cyanide method of extracting gold from ore. To his efforts this branch of the metallurgical industry owes a large measure of its success in continuing to treat some gold ores profitably, in spite of economic adversities. Mr. Merrill was born at Concord, N. H., Dec. 21, 1869, and received the degree of B. S. from the School of Mines at the University of California in 1891. Among his first professional connections was the Standard Mining Co., at Bodie, Cal., followed by a short engagement at Harqua Hala, Ariz. From 1895 to 1899 he was connected with the Montana Mining Co., at Marysvale, Mont., and then followed his nine years of fruitful association with the Homestake Mining Co. In 1909, the Merrill Co. was formed, to exploit more than a score of patents granted to Mr. Merrill, covering various phases of the cyanide process and numerous pieces of equipment for its operation; among the most noteworthy of these innovations were the Merrill filter-press, and the use of zinc dust as a precipitant. The Merrill Co. has a long record of successful accomplishments in its chosen field, to mention only the plants at the Dome mines of Ontario and at the Sta. Gertrudis mines of Mexico as among the more recent. Mr. Merrill is president also of the Western Ore Purchasing Co.; and a director in two gold dredging companies of California.

Jan 1, 1924

By A. B. Kinzel

INCLUSIONS of nonmetallic matter have long been recognized as objectionable in steel. A complete theory of the effect of inclusions, which is consistent with that held today, was outlined in Howe's early work on the metallurgy of iron and steel. This, by analogy with wrought iron, assumes that the observed difference in properties between specimens with and across the direction of rolling is due to slag enclosures. The fact that wrought iron shatters in ballistic test is taken as an indica-tion of the effect of inclusions on the resistance to shock. Since that time, the development of the metallurgical microscope has shown the discrete nonmetallic inclusions in the iron matrix. Better resolution has, brought out the great number of inclusions, and the availability of good microscopes in steel mills and laboratories has constantly drawn more attention to these inclusions. This recent emphasis on inclusions has resulted in studies as to their nature, mode of formation and methods of elimination, such as the work of Wohrman, Dickenson, Herty, and Schenk. In addition to the published works; many investigations which have not been published' have been carried out by private laboratories and have resulted in the application of specifications intended to limit inclusions in many qualities of steel. Nevertheless, a clear understanding of the quantitative effect of inclusions on the physical properties of steel has been lacking. It is the specific purpose of this study to determine the quantitative effect of inclusions on the physical properties of steel that determine its behavior under dynamic stress. The study has shown that a quantitative relation between counted inclusions and impact strength does exist in normalized steels, but 'that factors other than readily visible inclusions are equally important. Furthermore, the present commercial rating of inclusions is unreliable with respect to counted inclusions or dynamic tests, and this study indicates that the tensile-impact test is more reliable as a measure of quality.

Jan 1, 1931

By Herbert Clark Hoover, Lou Henry Hoover

PREVIOUSLY I have given much information concerning the miners, also I have discussed the choice of localities for mining, for washing sands, and for evaporating waters; further, I described the method of searching for veins. With such matters I was occupied in the second book; now I come to the third book, which is about veins and stringers, and the seams in the rocks1. The term "vein" is sometimes used to indicate canales in the earth, but very often elsewhere by this name I have described that which may be put in vessels2; I now attach a second significance to these words, for by them I mean to designate any mineral substances which the earth keeps hidden within her own deep receptacles.

Jan 1, 1950

By C. T. Bischoff

This paper describes the results of testing with colorimetric methods, using "dithizone", soil samples taken over various known copper and zinc deposits covered by glacial till. Variation in results is shown for different depths and types of overburden as well as grade and type of deposit. Limiting factors for the practical application of this work are discussed. The method has proved successful for copper and zinc deposits under clay and fine sand with depths up to at least 30 ft but fails in coarse sand and gravel unless depths are very shallow. Swamps require penetration to the underlying subsoil for sample material. DURING the past few years geochemical testing for traces of heavy metals in water, soil, rock, and vegetation has aroused increasing interest. Various techniques for field and laboratory determinations have been described in the literature, as have some of the results of application. However, little information has been published regarding application to glacial terrain. Over 90 pct of the Canadian Shield is overburdened, resulting in high costs for mineral exploration once the outcropping ore deposits have been found. This has been largely responsible for the widespread application of mining geophysics in Canada, permitting concentration of effort on area or zones considered most favorable. However, geophysical interpretation has its limitations, since at least 90 pct of the structures indicated thereby contain no valuable minerals. A more direct approach is therefore highly desirable. If underlying base metal mineralization can be detected by sampling soil or vegetation at moderate cost this should prove of great help in locating new discoveries or extending known ones. A large proportion of Canadian ore deposits contain appreciable copper or zinc, even where these are not the principal economic metals. Consequently the field of application is a broad one. This paper deals with investigations along these lines with particular emphasis on soil sampling. The problems involved from the start were: 1—Which types of glacial soil, if any, would best lend themselves to testing, and conversely which types might be considered relatively hopeless? 2—Through what depths of overburden could significant mineralization be detected? 3—What sampling techniques would prove economically applicable? This included minimum depth of sample and maximum spacing that could be allowed.

Jan 1, 1955

By Ralph M. Hunter

UNTIL recent years, maintenance of surface coal handling facilities was a relatively simple task. Equipment consisted principally of conveyors, screens and crushers of comparatively simple construction. Electrical equipment consisted of motors and starters, with little, if any, interlocking. In most cases failure of any component affected only the grades of coal loaded so that even a prolonged break-down did not affect mine operation materially. However, with the introduction of modern cleaning plants, the picture has changed. The equipment is much more complex and therefore more difficult to maintain. In many cases failure of any component of the plant prevents loading of coal. Even if provision is made to by-pass, the quality of coal loaded is lowered, affecting markets. In the case of plants designed to permit full seam mining, marketable coal cannot be loaded without operation of the cleaning plant. Under these conditions it is apparent that considerable thought and effort toward better maintenance are justified. In order to assure continuous, efficient and economical operation, maintenance should receive consideration, not only after the plant is in operation, but while it is being designed. It is hardly necessary to say that the designer should strive for sturdiness and wearing qualities. It is sometimes not realized, however, that even the best parts will sooner or later require replacement or repair. The designer should, therefore, give consideration to accessibility. Anyone who has had to do with cleaning plant maintenance is familiar with installations where several hours are required to get at a part that can be repaired or replaced in a few minutes, once it is accessible. As in most cases, experience is the best guide. The men who operate and maintain this equipment know the problems encountered. Whenever available, the opinions of these men should be sought and heeded. As an example, we might consider the refuse elevator on a Chance Cone. Our company is now operating three of these cones, the first of which was installed in 1941, and the latest in 2946. Exact records are not available, but well over 50 pct of delays charged to the Chance Cones have been caused by the refuse elevator. This elevator receives refuse from the cone and carries it to a point above the water level of the cone, discharging onto a dewatering and desanding screen. Since the elevator operates under water and necessarily has close clearances in the lower boot, it tends to jam on large pieces of refuse or tramp iron. The chain, buckets and boot are also subjected to the action of water, sand and refuse, which accelerate normal wear. In case of jamming or chain-breakage it is necessary to drain the elevator and the cone so that even a minor fault in the elevator causes a considerable loss of time for the cone. In our new plant, which will contain two Chance Cones, the refuse elevator has been eliminated. This was accomplished by raising the cone so that the refuse gates could discharge directly onto the dewater-

Jan 1, 1948

By Gilbert E. Doan

IN a technical civilization, that is. one whose major difference from past civilizations is its enormous development of technology, in transportation, communication, labor saving, centralized control, and mass production, it is natural that the most critical problems should be those that arise out of technologic advances; it is natural also that a. man who understands these advances should be chosen as the leader to meet these problems. This was done in the selection of Herbert Hoover as President of the United States. Mr. Hoover was a good, and perhaps a great President. But he was not a great politician and that ensured his defeat when a crisis came.

Jan 1, 1939

By M. B. Bever, A. B. Michael

The solidification of aluminum-rich aluminum-copper alloys was investigated for different solidification rates. The measured amounts of nonequilibrium eutectic were compared with the amounts calculated on the assumption of no diffusion in the solid. The morphology of the eutectic was studied and dendritic spacings were measured. Compositions of the cored primary solid solutions were determined by quantitative autoradiography after activation of the solute copper by neutron irradiation. CONSIDERABLE progress has been made in recent years toward an understanding of the solidification of metals. This is especially true for the factors involved in nucleation, the controlled growth of metal crystals from melts, and various aspects of the freezing of ingots and castings. Many features of the solidification process, however, are not understood adequately and much further work is required. In the research reported here the solidification of a series of aluminum-rich aluminum-copper alloys was investigated. Different degrees of deviation from the idealized case of equilibrium solidification were attained by varying the rate of solidification. Thermal analysis and microscopic examination were supplemented by lineal analysis and autoradiography. The latter required the use of radioactive tracers and was adapted to the quantitative determination on a microscale of concentrations of copper dissolved in aluminum. The tracers were produced in situ by activating the copper with neutrons. These techniques permitted a correlated interpretation of the temperature-time history, the amounts of nonequilibrium eutectic and the general morphology of the alloys, and yielded quantitative data on microsegregation. Nonequilibrium Solidification In the general case of the solidification of a solid solution in accordance with the phase diagram, the composition of the coexisting liquid and solid must change continuously. This change requires diffusion, which at best remains incomplete in the solid during solidification. The resulting inhomogeneity of the solid solution crystals is well-known as coring, dendritic segregation, or microsegregation. The generally accepted analysis of coring assumes that, 1—no diffusion occurs in the solid, 2—diffusion is complete in the liquid, and 3—the composition of the solid formed on cooling through any infinitesimal temperature interval is given by the solidus of the phase diagram. On this basis, In this equation m designates mass, x designates the concentration of solute and the subscripts L and S refer to the liquid and solid phases, respectively; the subscript o indicates the initial state, in which the liquid is identical with the entire system. Eq. 1 or its equivalent has been derived repeatedly'-7 and an analogous equation, known as Rayleigh's equation, has been used for distillation. The assumptions on which Eq. 1 is based do not include an infinitely fast cooling rate as sometimes stated. In fact, Olsen and Hultgren %ave shown by experiment that very high solidification rates suppress coring, presumably by preventing diffusion in the liquid and by the effect undercooling has on the composition of the nucleus. Coring thus occurs at rates of cooling which are too fast for a close approach to equilibrium in the solid and too slow to suppress diffusion in the liquid and to cause marked undercooling. If the liquidus and solidus approximate straight lines, Eq. 1 simplifies to The fraction of liquid present at any temperature during nonequilibrium solidification can be calculated from Eqs. 1 or 2. By the lever relation it is

Jan 1, 1955

By John Chipman

THE equilibrium between titanium in liquid iron and titanium oxides has been studied by Hadley and Derge.' They have shown that a minimum occurs in the oxygen content of the metal between 0.1 and 1.0 pct Ti, but its exact level was not fixed. The oxide phase in this minimum range was principally TiO, containing some iron oxide. On the other hand, for concentrations above 5 pct Ti the oxide phase was TiO and the oxygen content of the metal increased rapidly with increasing titanium content. From their observations and the free energy of Ti0 and TiOz reported by Kelley and ah,' it is possible to derive approximate values for the activity coefficients of titanium and oxygen in liquid iron-titanium alloys and the conditions for equilibrium in steel deoxidation. Neglecting possible departures from the stoichio-metric composition, the condition of equilibrium with Ti0 may be expressed as follows: TiO= Ti_ + C) log K = log NTl + log [% O] + log yTi + log fQ Here as a matter of convenience the titanium concentration is expressed in mol fraction while that of oxygen is in weight percent. The activity coefficients are yTi and fo. The value of log fo approaches zero as the concentration of titanium approaches zero, while that of log yTi approaches a limiting value of In Fig. 1 the sum of log NTi + log [% 0] is plotted for mol fractions of titanium between 0.05 and 0.50. The smooth extrapolation gives a value of —4.15 which corresponds to log K — log y:i . We therefore have the equation: According to the data of Kelley and Mah,' the free energy of formation of Ti0 at 1900°K is -82,400 cal. The free energy of solution of half a mol of oxygen in iron, taking 1 pct 0 as the standard state, is -29,300 cal. From these we write: From these equations the activity coefficient of titanium at infinite dilution in iron is found to have a value of 0.011 or log y°. = -1.96. This is only an approximate value but is certainly better than the estimated 0.05 in Basic Open Hearth Steelmaking To obtain approximate values for the activity coefficient at intermediate concentrations, it is as- sumed that log yTi(l is constant and equal to -1.96. This corresponds to a value of E;: = 3 In yTi/aNTi = 9.0 which is not unreasonable We now have the value for the activity of titanium and the percentage of oxygen in equilibrium with TiO. It is therefore a simple matter to calculate the activity coefficient of oxygen which is shown in Fig. 2. The effect of titanium is rather large, being comparable to that of vanadium, but not so large as has been reported for aluminum. The slope of the line at low concentrations corresponds to E: = aln yo/ aNTi=-0.37. At concentrations below 1 pct Ti the deoxidation constant and oxygen content for equilibrium with TiO, can be calculated from the foregoing data and the free energy of formation of TiO,, which according to Kelley and Mah is -144,600 cal at 1900°K. The free energy of solution of oxygen has been given; that of Ti to form a dilute solution with 1 pct Ti as the standard state is RT ln (0.5585 y:i/47.9) = -34,800 cal. From these data we find (for concentrations in wt pct): TiO, = Ti + 2 -0; hFTgO0= + 51,200 cal log if =-5.89 The interaction coefficients, concentrations being expressed as wt pct, are e;: = alogfTi/a[% Ti] = +0.048 and e:' = a logfo,/a[ojTi] = -0.187. The calculation gives the following results which, in view of the impurity of the oxide phase, must be regarded as approximate:

Jan 1, 1961

By AIME AIME

In taking account of stock, on the occasion of the recent removal of the office of the Institute, it was found that pamphlet copies of the papers named in the list given below were on hand, in excess of the average number deemed adequate for future casual demand. Special reduced rates will be made for these surplus copies to members applying promptly. "First come; first Served." Author. Title. Ref. No. ASHBURNER, C. A. " Petroleum and Natural Gas in New York State." 273 MARTENS, A. "The Microstructure of Ingot¬ Iron and Cast Ingots." 626

Jan 1, 1907

Meeting of Apr. 23, 1915.-The Iron and Steel Committee was authorized in its discretion to defer the date of acceptance of papers for the Hadfield Research Prize to Nov. 1, 1916. The sum of $250 was appropriated as a guarantee fund to establish a Library Research Bureau in co-operation with the other Founder Societies. The sum of $50 was appropriated to the Puget Sound Section. The sum of $250 was appropriated to the San Francisco Section. The sum of $125 was appropriated to the St. Louis Section. The matter of memorializing the New York State Constitutional Convention was referred to the New York Section of the Institute with authority to act as a Section only. Upon recommendation of the Committee on Membership, 50 Mem¬bers, 1 Associate, and 6 Junior Members were elected.

Jan 6, 1915

By Charles Goodale

With notes on other mines of the Marysville district by WALTER McDERMOTT, London, England, and F. L. Sizer, Dos Cabezas, Ariz. (Salt Lake Meeting, August, 1914) THE purpose of this paper is to review the history of the Drumlummon, one of the famous old mines of the West. Mining engineers, when sent to examine new mines in old districts, or to decide whether an old property, under new conditions, will pay to re-open, have had difficulty in learning anything authentic regarding workings which are under water, and historical facts about the working character of the ore, the total production, and the value of the ore with increasing depth. Not many years elapse after the pumps are pulled, before maps, books and records are destroyed, and the value of the publications of the Institute would be increased if they contained the history of many old mines now abandoned. The unsuccessful efforts of the writer quite recently in trying to obtain reliable information about a gold mine which was reported to have produced several million dollars between 1880 and 1888, the workings of which are now partially caved and under water, impressed upon his mind the desirability of having a permanent record of old properties. In this particular case, the owners insisted that under present conditions of improved methods of treatment -particularly by the use of cyanide, which was not an applied process when the mine was operated, the property. could be made to pay a handsome profit on ore left in sight in the old workings, but no assay records could be found to confirm these assurances, and even the records of bullion shipments had been destroyed. If surveys and maps were made as the work progressed, no trace of them could be found, and therefore opening of the ground through a new shaft and drifts therefrom would be attended by some risk while exploring near the old workings. Fatal accidents by flooding under these conditions have occurred, and as an evidence that miners have fears of such dangers, it was urged upon the Mining Committee during a recent session of the Montana Legislature, by a delegation of

Jan 8, 1914

By Gorr W. W., Wyche E. H, R. Smith

The combination of high strength and corrosion resistance of cold-worked 18 Cr, 8 Ni steel has been advantageously utilized for some time, particularly in aircraft and rail car structures. There are, however, certain limitations on the use of such materials because the high strengths can be obtained only by cold-working, limiting the available products to sheets, strip, wire and tubes. The authors sought to overcome these limitations by resorting to precipitation-hardening, which has been used so successfully in nonferrous metallurgy but only to a limited extent in iron-base alloys. Accomplishment of this objective not only overcame the limitations, but also effected certain improvements in mechanical and other properties. This paper is an account of the development by Carnegie-Illinois Steel Corporation of a precipitation-hardening 18-8 stainless steel (called Stainless W‡ and tentatively identified as type 322). A description is given of its composition and metallurgical characteristics, heat-treatment, physical and mechanical properties and corrosion resistance. Development of the New Steel For a considerable length of time the authors were unable to determine the mechanism of the precipitation-hardening process that had been noted by Ffield18,19 in 18-8 Ti or 18-8 Cb after cold-working and reheating to moderately elevated temperatures. All known variables were exhaustively studied, but with little success. However, results began to indicate that chemical composition was the most important variable, particularly the ratio of austenite-forming to ferrite-forming elements. The investigators then focused their attention upon the composition, and, in particular, upon the element titanium and its mode of alloying in the presence of other elements. A heat was obtained that could not be brought to the softness level of annealed 18-8. The response to cold-straining and aging* was very marked by previous standards, and, more important, cold-straining was found to be entirely unnecessary to produce the precipitation-hardening effect. The chemical composition of this heat was: C, 0.06 per cent; Mn, 0.54; P, 0.016; S, 0.016; Si, 0.58; Ni, 7.28; Cr, 17.60; Ti, 0.90; Al, 0.17. For some time the development work, particularly on composition, was carried

Jan 1, 1947

By Gorr W. W., R. Smith, Wyche E. H

The combination of high strength and corrosion resistance of cold-worked 18 Cr, 8 Ni steel has been advantageously utilized for some time, particularly in aircraft and rail car structures. There are, however, certain limitations on the use of such materials because the high strengths can be obtained only by cold-working, limiting the available products to sheets, strip, wire and tubes. The authors sought to overcome these limitations by resorting to precipitation-hardening, which has been used so successfully in nonferrous metallurgy but only to a limited extent in iron-base alloys. Accomplishment of this objective not only overcame the limitations, but also effected certain improvements in mechanical and other properties. This paper is an account of the development by Carnegie-Illinois Steel Corporation of a precipitation-hardening 18-8 stainless steel (called Stainless W‡ and tentatively identified as type 322). A description is given of its composition and metallurgical characteristics, heat-treatment, physical and mechanical properties and corrosion resistance. Development of the New Steel For a considerable length of time the authors were unable to determine the mechanism of the precipitation-hardening process that had been noted by Ffield18,19 in 18-8 Ti or 18-8 Cb after cold-working and reheating to moderately elevated temperatures. All known variables were exhaustively studied, but with little success. However, results began to indicate that chemical composition was the most important variable, particularly the ratio of austenite-forming to ferrite-forming elements. The investigators then focused their attention upon the composition, and, in particular, upon the element titanium and its mode of alloying in the presence of other elements. A heat was obtained that could not be brought to the softness level of annealed 18-8. The response to cold-straining and aging* was very marked by previous standards, and, more important, cold-straining was found to be entirely unnecessary to produce the precipitation-hardening effect. The chemical composition of this heat was: C, 0.06 per cent; Mn, 0.54; P, 0.016; S, 0.016; Si, 0.58; Ni, 7.28; Cr, 17.60; Ti, 0.90; Al, 0.17. For some time the development work, particularly on composition, was carried

Jan 1, 1947

By L. A. Rapport, J. R. McCord, W. P. Drews, K. H. Coats

Water movement about an oil or gas reservoir can be predicted provided an aquifer influence function is known. This function is generally determined from an electric analyzer study or by fitting an idealized mathematical model to field data. A prohlem arises in determining that influence function which best reproduces field data and satisfies certain smoothness requirements, without making any idealizations concerning aquifer geometry and heterogeneity. This study shows the problem to be solvable through the linear programming technique and presents applications to one oil reservoir and two gas storage reservoirs. In addition, a theorem is stated and proven which confirms influence junction smoothness requirements heretofore accepted on physical intuition and establishes additiotzal smoothness constraints formerly not recognized. INTRODUCTION The pressure decline accompanying production results in water encroachment into oil and gas reservoirs situated adjacent to aquifers. The importance of this water movement derives from the significant dependence of production rate upon reservoir pressure and of pressure, in turn, upon water encroachment. Pressure and rate of water movement are uniquely related through an "influence" function which may be in the form of reservoir pressure response to a unit water encroachment rate or of water movement caused by a unit reservoir pressure drop. This influence function reflects the heterogeneity and geometry of the aquifer and is therefore particular to each reservoir. If the influence function is known, then reservoir pressure may be predicted from a production rate schedule, or vice-versa, with the aid of the material balance equation which relates water influx to reservoir production and pressure. The problem of determining this influence function for a given reservoir has been approached in three different ways. Van Everdingen and Hurst calculated and tabulated certain influence functions pertinent to idealized mathematical models which satisfy simplifying assumptions such as aquifer homogeneity and elementary reservoir-aquifer geometries.' Other studies developed additional tables for a variety of elementary reservoir-aquifer geometrical con- figurations and demonstrated their validity and utility.:' Hicks, et al. described the use of an electrical network to determine an influence function giving "best" match of field history and allowing prediction of future performance.' Finally, Hutchinson and Sikora5 and Katz, Tek and Jones attempted to develop a calculation method for deriving the influence function directly from field data with no idealizing assumptions concerning aquifer geometry and homogeneity. They encountered difficulties with inaccuracies in field data and with satisfaction of well-known smoothness requirements of the influence function. This study is concerned with the determination of influence functions from field data and, more specifically, treats the following problem: given field pressure-production data of arbitrary accuracy, how does one determine the influence function which, subject to satisfaction of known smoothness requirements, gives best agreement with field history? A rigorous solution to this problem is ohtained through linear programming as described below. Example applications to one oil and two gas storage reservoirs are presented. In addition, a theorem is proved which confirms influence function smoothness requirements heretofore accepted on physical intuition and establishes additional smoothness requirements formerly not recognized.

Jan 1, 1965