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By O. B. Hopkins

The total production of oil in Peru in 1940 was 12,127,135 bbl., or about 10 per cent less than in 1939. Most of the reduction can be attributed to the fact that the export market under war conditions is much restricted and naturally is more than ordinarily competitive. Development and Exploration in Older Areas As evidenced by Table I, almost all production continued to come from the three established fields in coastal northwestern Peru. Zorritos Field.—Exploration in this small field, which was purchased by the Peruvian Government in 1939, continued with that in near-by areas in the adjoining National Reserve. Several wells were drilled, regarding which details are not as yet available. It is estimated that the production rate for a total of some 45 old and 15 new wells approximated zoo bbl. per day, or about 3 bbl. per well per day. Lobitos Fields.—The Lobitos area produced 2,435,504 bbl.; about 10 per cent less than the amount for 1939. La Brea-Pari9zas.—This property of International Petroleum Co. continued to account for nearly 80 per cent of Peru's production. During the year, drilling was stepped up to 139 wells, as compared with 73 wells completed in the previous year; 123 were producers and aggregated a total of 287,867 ft. Of this total, more than 85 per cent was drilled by rotary tools, which are steadily displacing other equipment. Although most of these wells were drilled in the proved or semiproved areas, eight

Jan 1, 1941

By O. B. Hopkins

The total production of oil in Peru in 1940 was 12,127,135 bbl., or about 10 per cent less than in 1939. Most of the reduction can be attributed to the fact that the export market under war conditions is much restricted and naturally is more than ordinarily competitive. Development and Exploration in Older Areas As evidenced by Table I, almost all production continued to come from the three established fields in coastal northwestern Peru. Zorritos Field.—Exploration in this small field, which was purchased by the Peruvian Government in 1939, continued with that in near-by areas in the adjoining National Reserve. Several wells were drilled, regarding which details are not as yet available. It is estimated that the production rate for a total of some 45 old and 15 new wells approximated zoo bbl. per day, or about 3 bbl. per well per day. Lobitos Fields.—The Lobitos area produced 2,435,504 bbl.; about 10 per cent less than the amount for 1939. La Brea-Pari9zas.—This property of International Petroleum Co. continued to account for nearly 80 per cent of Peru's production. During the year, drilling was stepped up to 139 wells, as compared with 73 wells completed in the previous year; 123 were producers and aggregated a total of 287,867 ft. Of this total, more than 85 per cent was drilled by rotary tools, which are steadily displacing other equipment. Although most of these wells were drilled in the proved or semiproved areas, eight

Jan 1, 1941

As we understand the functions of the A. I. M. E. Petroleum Division, they are to discover and promote knowledge for the benefit of society on the mining of oil and gas. To the individual member of the Petroleum Division, there are certain advantages of social and professional contacts, but the collective purpose is that described. And the individual is benefited by membership only as the Division measures up to the purposes of its existence. Consequently, the welfare of this Division and that of its members depends upon the extent to which it keeps pace with the needs of society on matters relating to the mining of oil and gas. To some extent, A. I. M. E. activities must be determined by the changing current needs of society. The great problem ahead of the world for some time is to evolve equitable types of production control in many industries, and especially is that true of the oil industry. Production control in this industry is as much an engineering function as is production development, notwithstanding it also involves the lawyer, the economist and the politician. It must be built on and around suitable engineering planning enforced by public opinion and legislation. We believe the prerequisite to any satisfactory solution of the oil industry's ills is an educational campaign establishing a better public understanding of the needs and merits of production control, by which we mean the maximum yield at the minimum cost coordinated to society's current needs. The underlying causes of the oil industry's ills are well known and generally agreed upon. In like manner there is general agreement among students of the industry that the first step toward their correction would be general adoption of oil-field developing and operating methods that would permit most efficient use of reservoir energy; that would provide for equitable distribution of oil and gas among the several owners in the pool; and also for the extraction of these products in response to market demand. It is now found, however, that general adoption of such developing and operating methods unfortunately cannot be brought about without changes being secured in certain basic laws of oil and gas, and perhaps also in the anti-trust laws. These legal changes are difficult to secure because of the widespread fear that they would tend to place the oil industry more exclusively in the hands of the major companies, and that

Jan 1, 1932

By Karl W. Mote

CALIFORNIA'S iron and steel industry had its beginning in San Francisco in 1849 when the first iron casting was poured at the old Union Iron Works. Soon after, in 1856 at Grass Valley, enough iron ore was smelted to supply pig iron for the castings of a quartz mill there. From 1880 to 1886, iron ore was produced from the Hotaling mine in Placer County and converted to pig iron in a local blast furnace using charcoal. From 1907 to 1914, the Noble Electric Steel Co. produced pig iron from iron ore mined at the Shasta Iron Co. mine, and followed this for three years in the production of ferro-alloys. Between 1917 and 1941, the State's industry in- creased its capacity for open hearth and electric furnace scrap treatment, but the real impetus was supplied by the need for more steel at the beginning of World War II. The result was the State's first integrated steel plant-the Kaiser Steel Corp. facilities at Fontana.

Jan 7, 1958

By Ralph Arnold

IN OPENING the symposium under the auspices of the Petroleum and Gas Committee of the American Institute of Mining and Metallurgical Engineers, I wish to call to your attention the following, among other subjects, which it is hoped may receive proper attention: 1. The recording of as accurate an appraisal of the oil possibilities of the various countries as is possible, with information as to the immediate availability of their supply. 2. The development of further support for the move-ment to bring about active cooperation among Ameri-can oil companies in their foreign exploration and development work. 3. The furtherance of the efforts of the industry in securing governmental assistance in foreign oil develop-ment: (a) along the lines of a modification of our domestic oil policy, so that we can go to foreign coun-tries and consistently ask fair treatment as to royalties and bonuses; (b) by a closer cooperation between the State and Commerce Departments and the oil industry. 4. The calling of attention to the unjustifiably drastic action of the price-fixing group of the oil industry during the last year or so, with the hope that it will use gentler methods in the future. None of these subjects are new, and some of them have been discussed before various organizations for years. Our justification for again bringing them forward is the hope that by everlastingly harping on them the industry, the Government, and the people who shape the destinies of this country may some time, some how, realize their importance and take effective constructive action.

Jan 6, 1922

By Victor Rakowsky

A CLEAR understanding of the factors that deter-mine the consumption of zinc metal is essential to a proper survey of the future of the industry and the relation of the several producing districts. With a view of explaining a sound basis for the consider-ation of some of the problems facing the zinc-mining industry of the Oklahoma-Kansas and Missouri district some of these factors are here set out. The zinc industry of the United States furnishes metal for three major uses, viz.: (1) zinking iron and steel (galvanizing); (2) brass making; (3) sheet rolling. Other important uses are for lead desilverization, the manufacture of castings, including die castings, and the manufacture of zinc oxide by the French process, which consists in burning spelter. The use of zinc for galvanizing comprises the coating of sheets, tubes, wire and shaped products, the latter ranging from chains to buckets. The brass-making industry may be sub-divided into manufacture of red brass, yellow brass and white brass, the percentage of zinc in these products being roughly 30, 40 and 80 respectively. The use of white brass is relatively a new thing and it may attain considerable proportions as a substitute for yellow brass. Ingalls estimated the percentage of total metal consumed for the above purposes in pre-war times as follows: HIGH PRODUCTION RECORD, SHORT TONS USES PERCENTAGE OF METAL Galvanizing 60-65 210,000 in 1912 Brass making 17-20 175,000 in 1916 Rolled sheets 10-12 57,000 in 1917 Other uses 5- 7

Jan 3, 1923

PUBLIC hearings began before the Committee for Reciprocity Information on May 24, 1950, for the purpose of unearthing data and opinion that will be helpful in the forthcoming reciprocal tariff and other trade-barrier negotiations at Torquay, England, on September 28th of this year. The conference this fall will constitute the "third round" of tariff negotiations under the General Agreement on Tariffs and Trade concluded at Geneva in 1947. The United States plans to negotiate with 17 other countries on possible tariff modifications on various articles all the way from baby carriages and bottle caps to lead and zinc-bearing ores. On May 31, June 1 and June 2, spokesmen appeared before the Committee for Reciprocity Information on behalf of the domestic lead and zinc mining industries. Producers of these metals protested the inclusion of paragraphs 391 (lead-bearing ores, dust and mattes), 392 (lead bullion, lead in pigs and bars, and scrap lead), 393 (zinc-bearing ores of all kinds), and 394 (zinc in blocks, pigs or slabs, and zinc dust) of the Tariff Act of 1930, as amended in the list of articles to be considered for possible tariff concessions at Torquay. It was pointed out that although operating costs have more than doubled since 1939 tariffs on these metals were actually higher in that year than at present. This, coupled with the detrimental effects of the recent series of devaluations, has sounded the death knell for a substantial number of domestic lead and zinc mines-a most undesirable development in the face of the ominous international situation, according to these spokesmen. It was urged that higher rather than lower tariff rates are needed on these metals. The opinion was expressed that it was inconsistent to foster a high living standard in our western areas and then, once it is attained, to undermine that condition by minimizing the protection that was partly responsible for it. The main theme of some arguments implied that although every effort should be made to close the "dollar gap" abroad, serious consideration must be given the methods employed lest our national security position be jeopardized in the process. The House Committee on Foreign Affairs completed hearings on H. J. Res. 236, to provide for United States membership and participation in the International Trade Organization. Hearings began on April 19th and ran for over five weeks. Many witnesses from industry and government presented voluminous testimony, which will not be available for public distribution for several weeks. However, it is no secret that the most controversial provisions of the Draft Charter of the ITO are: (1) Article 17 (Chapter IV on Commercial Policy) which would obligate members to negotiate for the reduction of tariffs and the elimination of trade preferences; (2) Article 20 which would prohibit the use of quantitative restrictions for protective purposes; (3) Article 16 which promulgates rules to implement the principle of non-discrimination in international trade; and (4) provisions permitting the use of protective measures for promoting economic development, particularly in backward areas, even though such provisions are inconsistent with those of the three articles cited above. United States membership in the International Trade Organization is essential to the successful operation of that body in view of this country's position as the economic giant in the present international trade pattern. Many countries are reluctant to take any action toward the ratification of the charter until it is known what course America will pursue. However desirable or undesirable the ideal of free multilateral trade may be it is unlikely that this Government's participation in the ITO will materialize soon. Advices in Washington indicate that H. J. Res. 236 will not be enacted during the present session of Congress. The legislative pattern designed to secure Congressional approval of the ITO is similar to that of the St. Lawrence Seaway project. The Seaway project was pending in treaty form for several years before the Foreign Relations Committee of the Senate and when the Administration decided to incorporate this project into bill form it was found that, while it passed the House promptly, the Senate decided to pigeonhole it because of the obvious intent to circumvent the constitutional prerogative of the Senate to advise and consent to the ratification of treaties. The ITO bill may be slated for a similar fate. It is deemed essential by western Senators and Congressmen that the present session of Congress enact some form of mining legislation before its adjournment, now set for July 31st. These legislators from prominent ore-producing states do not desire to return to their home areas in the fall emptyhanded. Aside from that, it is entirely superfluous to reiterate the necessity for maintaining a healthy domestic mining industry as a bulwark against a sharp rise in the temperature of the "cold war". Now that S. 2105 has failed a new bill is taking shape in the Senate Interior and Insular Affairs Committee. It is similar in language to H. R. 8221 (to encourage the conservation and development of the mineral resources of the United States) reported by the House Public Lands Committee on May 3, 1950, but so far has failed to receive approval of the House Committee on Rules. There are some qualified observers in high circles in Washington as well as in the mining industry who favor a tax incentive program to stimulate investment in mining enterprises, as opposed to a conservation and exploration program. The Bureau of Mines and the Treasury Department have undertaken a joint study to determine the need for modification of the tax laws as they apply to mining. The study is scheduled for completion before the end of the year, and appears to be supplementary to the investigation initiated by the National Minerals Advisory Council which culminated in the submittal of recommendations to the Secretary of the Interior in December 1949. The "cold war" is largely responsible for the increased demand for metals. Stock-pile purchases and heavy industrial demand due to military needs distort markets and disrupt normal price trends. Such activity has an unhealthy influence on metal production, luring some producers into a state of dependency on the continuation of this condition. When stock-pile objectives are met sometime in the future purchases must then come to a halt unless international "fireworks" are touched off. It can only be hoped that technological improvements and further mechanization of mines coupled with the stimulus of a rising population will offset the anticipated drop in industrial demand and cessation of stockpile purchases when the international crisis abates.

Jan 7, 1950

By AIME

D R. GILLSON, who was born in Evanston, Ill., in 1895, is another one of those geologists who received his early inspiration and foundation in his science from that great teacher at Northwestern University, the late Professor U. S. Grant, and then went on to give his time and interest to Institute affairs-like those other Northwestern men, Arthur Blair, Gilbert Cady, Charlie Behre, Evan Just, Ian Campbell, Clayton Ball, and many others. After serving in the Navy in the first World War as, of all things for a geologist, a commissary officer on a transport, he went on to MIT and took his doctor's degree under Waldemar Lindgren in 1923. He even assisted in mineralogy at Harvard and thus had training under another great teacher, Charles Palache. He taught mineralogy and petrography at MIT from 1923 to 1928. After several summers of field work as an assistant in the U. S. Geological Survey, Dr. Gillson joined the staff of the du Pont company.

Jan 1, 1947

By Bashir Ahmed, Fred D. Wright

Numerous investigators have studied the various factors that influence the ultimate strength of model mine pillars, such as ratio of height-to-least width; restraint or friction on the top and bottom; 1,2 the effect of stress distribution in pillars on their strength;3 and the scaling factors involved in applying the results of model pillars to full-scale pillars. However, the load-bearing capacity of pillars after initial failure does not appear to have been investigated. Yet many mines employ methods in which small pillars or pillar remnants are left systematically; these pillars crush as mining progresses and, of necessity, affect the behavior of surrounding rock even after initial failure. The effect of such crushed or crushing pillars depends largely on their load-deformation characteristics. This chapter presents the results of a preliminary investigation to determine the load-deformation characteristics of a few model mine pillars to and beyond initial failure. Various investigators have also studied the elastic and viscoelastic behavior of mine structures. In such studies, computers are frequently employed to obtain numerical results by the finite difference or finite element methods. It would be entirely feasible to write a program that would approximate the load-deformation characteristics of pillars to and beyond the crushing stage if these characteristics were known. More accurate information on the induced stresses and deformations in overlying strata and on surface subsidence could be obtained, information which should result in better strata control by enabling the engineer to calculate more accurately the effects of changes in pillar spacing, size, and shape.

Jan 1, 1972

By S. R. Elliott

The principles of the caving system, as they apply to mining soft iron-ore deposits, are well known, as this method has been in use for many years. It is, however, necessary to give a general description of it before describing the Athens method. The shaft and surface equipment should be placed at a sufficient distance from the orebody, so that the caving and pulling of the surface will not disturb the operations of the mine. Levels are started at the proper intervals, and when raises are completed, slicing commences at the top of the orebody and progresses downward. The necessary precautions are taken to avoid the occurrence of large open rooms and it is customary to break sufficient capping to form a mat to prevent heavy falls of ground from crushing through to the lower sublevels and endangering the lives of the workmen. Slicing is continued, and when sufficient width and length are undercut, the capping commences to cave, and in time a settlement occurs at the surface. As soon as this caving commences, the pressure on the timber increases; after it extends to the surface, the amount of pressure has a certain relation to the depth. In other words, the pressure increases with the depth, but not in direct proportion. At great depths, such as are found at the Athens, 2500 ft. (760 m.), the pressure might be so excessive that the cost of keeping working places open would be prohibitive. The actual caving of the surface in a deep mine, with a great thickness of capping, is slow and often takes years to accomplish. After sufficient width and depth have been undercut, the capping starts to break away, but, through arching, large masses of rock fill the opening, support the capping, and retard the continuation of caving. Caving to the surface is, therefore, retarded until either a sufficient thickness of the orebody is removed, or the width and length of the undercut part have been greatly increascd. I wish to emphasize this fact of slow caving, for it is on this principle that the success of the Athens system largely depends. Assuming that work is begun at the top, in this case at an elevation of about 1500 ft. (456 m.); that there is a thick bed of sand saturated with

Jan 1, 1922

By E. V. Given

In speaking of the concentration of oxidized lead ores at St. Anthony, I do not wish to infer that we believe all lead ores of a similar grade can be mined and treated at a profit. Our oxidized ore is low grade, and certainly the mine under present economic conditions could not operate on this ore by itself. Because of favorable conditions we can operate the oxide circuit at a small profit although we do not allocate overhead, pumping, and certain other general charges to it. Operations in the oxidized zone were started as an essential part of the development necessary to outline and mine the sulphide ores. Nearly all of our oxidized lead ore comes from the Collins section of the mine, with the transition from oxide to sulphide ore lying between the 600 and 700-ft levels. Production from sulphide ore is much larger than from the oxide, both in tonnage handled and in grade of ore. The oxide and sulphide ores are never mixed either in the mine or the mill. The oxide mill sections have their own ore bins, grinding, and flotation departments. The lead minerals contained in the ore, in the order of their importance are cerussite, wulfenite, galena, anglesite, and vanadinite. The ratios of the different lead minerals change as the ore is pulled from different parts of the mine-total lead being approximately 50% to 60% cerussite, 20% wulfenite, 15% galena, zero to 10% anglesite, and 2% vanadinite. About 3% of the lead was unidentified.

Jan 5, 1950

President Howe: It is, of course, not easy to discuss off-hand the paper which Mr. Becker has presented with so much lucidity. I will only make one remark, which is outside of the line of his argument, and concerns merely a passing allusion in his paper. Mr. Becker speaks of the fact that glass breaks with a flat or conchoidal fracture, and that steel shows a rough or " cupped " surface of frac-

Jan 1, 1895

By W. A. Oates, J. S. Blakemore, E. O. Hall

AS part of an investigation into the effect of hydrogen on the serrated yielding of Ni-Cu alloys,' it was necessary to determine the solubility of hydrogen in the alloys of interest. With the exception of the work by Fukusima and Mitui2 who investigated the solubility of hydrogen in solid Ni-Cu alloys at 20 wt pct intervals at 1050°, 700°, and 350°C, the information in the literature is limited.3-10 Alloys were prepared from deoxidized Analar Copper and Mond Nickel pellets.' Wire samples were hydrogenated at 7.8 atm in an autoclave consisting of 5 ft of thick-walled Inconel 600 tube with a resistance furnace around the middle portion. The top end, at room temperature, was fitted with a safety valve, a calibrated pressure gage, and a sample inlet, while the bottom end, again at room temperature, was filled with water. After reaching equilibrium samples were quenched by dropping from the high-temperature region of the autoclave into water. They were then quickly transferred to liquid nitrogen where they were stored until analyzed for hydrogen using an Exhalograph.11 The results, which are shown in Fig. 1, represent the mean of two separate determinations on each sample. Because of the lower level of hydrogen at the high copper end of the series, the results here are of poor precision using this method. Fortunately, the results of Himmler9 using the Sieverts technique are available for these copper-rich alloys (>80 at. pct Cu)

Jan 1, 1969

By R. S. Dean

ALTHOUGH it is obvious that in any flotation process we must have a froth, in recent years the development of collecting reagents has caused the possibilities of better frothing agents to be overlooked. Some investigators have even gone so far as to say that the number of satis-factory frothing agents was sufficient. A little consideration will show, however, that the reagents available in the past were far from ideal frothers. The properties of an ideal frother for flotation work may be set down as follows: 1. It. must form in low concentrations a copious but not too persist-ent froth. 2. It must be insensitive to hydrogen-ion concentration of the pulp; that is, it must froth equally well in an acid or alkaline medium. 3. It must be insensitive to salts, even in high concentration. 4. It must be absolutely noncollecting to both sulfides and nonsulfides. 5. Its frothing properties must not be affected by collecting reagents, including soap, the most generally used nonsulfide collector. 6. It must readily emulsify and disperse any insoluble collecting agent that is likely to be used. Clearly the existing frothers do not qualify. Pine oil, for example, is an acceptable frother for many purposes but if used in soap flotation a delicate balance between pine oil and soap must be struck because, as pointed out by Coghill1, these two reagents are incompatible in certain concentrations. The objections to soap itself as a frother are obvious, and the cresols and their substitution products all have some collecting Dower and very little emulsifying power.

Jan 1, 1935

By D. L. Katz

A PHASE diagram showing boundary curve and quantity of liquid in the two-phase region was determined for a mixture of natural gas and natural gasoline in the region of its critical conditions. The tempera-tures and pressures of phase measurements were in the range of 85° to 212° F. and 1300 to 2600 lb, per sq. in., respectively, with the critical conditions at 169.5° F. and 2615 lb. per sq. in. abs, Color phenomena were observed in the region of the boundary curve from 102° to 192° F. Approximate densities of the single-phase and two-phase regions and analysis of the system are included. Boundary curves between the single-phase and the two-phase regions have been determined for several binary mixtures containing hydro-carbons. 2,3,4,6,7,10,11,12,14 These investigators did not report the relative amounts of liquid and vapor within the two-phase region. The equilib-rium values obtained from the dew-point and bubble-point data can be used to compute the lines showing percentage of liquid on the pressure-temperature phase diagrams but the positions of the lines near the critical temperature and pressure are uncertain. Relative amounts of vapor and liquid were obtained for a gasoline and a naphtha' within the two-phase area but not in, the region of the critical temperature and pressure. The bubble-point and dew-point lines, as well as the percentage liquid lines within the two-phase region, were determined by visual observations in glass apparatus.

Jan 1, 1939

By R. L. Andelin, J. D. Knight, M. Kahn

Self-diffusion in single-crystal tungsten and diffusion of rhenium tracer in single-crystal tungsten have been measured over the temperature range 2660° to 3230°C by direct sectioning and radio-chemical analysis of W185 and Re183 and Re184 tracers. The initial radioactive layer was produced on the diffusion specimens by bombardment with 9.0-mev deuterons. Diffusion heating of the samples in high vacuum was accomplished by induction heating. Temperatures were measured by optical pyrometry, and the system was calibrated ALTHOUGH a considerable body of experimental information has been accumulated on self-diffusion in solids, the major part of the detailed work has by reference to the melting points of tantalum (2996°C), molybdenum (2620°C), niobium (2468°C), and rhodium (1966°C). The diffusion coefficients for the two systems, obtained by least-squares analyses of the data, are well-represented by the equations thus far dealt with relatively low-melting systems. Diffusion studies on the high-melting elements niobium,1 tantalum,2,3 and tungsten4'5 have been limited to polycrystalline material, for which data interpretation and theoretical analysis are sometimes difficult. Only recently, a study has been made with single-crystal molybdenum.6 The present work deals with the measurement of self-diffusion in single-crystal tungsten at temperatures approaching the melting point (3410°c).7 Since the method chosen for producing the radioactive tracer layer-bombardment with deuterons—produced detectable isotopes of rhenium as well as of tungsten, the diffusion of rhenium was measured also.

Jan 1, 1965

By E. D. Hummer

During the planning of the fine coal cleaning addition at the Gary, W. Va., Coal Preparation Plant of United States Steel Corp. careful consideration was directed toward the problem of minus 48 mesh refuse disposal. The plant flow sheet included wet screening the raw coal at ¼ in., pumping the minus ¼ in. raw coal to bowl desiltors for desliming, and then cleaning the deslimed raw coal on tables. The material to be removed from the circuit as minus 48 mesh refuse consisted of the minus 100 mesh desiltor overflow thickened in two 120 ft diam thickeners and minus 1 mm screened from the table refuse. Later a flotation plant was added to recover coal from the desiltor overflow, and a classifier replaced the screens to make a sharper size separation of the table refuse at 48 mesh. Today the minus 48 mesh refuse at Gary consists of thickened flotation tailing and thickened spiral classifier overflow. The transportation of large quantities of fine, wet refuse filter cake mixed with jig and table refuse over existing conveying equipment would have been neither dependable nor economical. Filtration was therefore impractical, and disposal of the fine materials was a problem. The decision was to pump the material to storage ponds.

Jan 3, 1965

By R. S. Sandhu, L. E. Baker, W. Y. Shieh

The finite element method of analysis was introduced by Clough.1 Within a short period, it has developed into a powerful solution technique in structural and continuum mechanics. It has been used to solve boundary value problems in two and three-dimensional elasticity.2-5 Anisotropy and heterogeneity of materials were allowed for at the earliest stages. 1,4 Its application has been extended to allow for cracks,5 creep and viscoelasticity, 6,7 incremental construction,6-8 nonlinear elasticity3,9 effect of joints in rock,10 and to materials with different behavior in tension and compression.7 Because of its versatility, the finite element method has found increasing application in the field of rock mechanics. In fact, several of the more significant developments have been motivated by problems in this field. Elasto-plastic material behavior based on the incremental or rate-type theory of plasticity rather than the deformation theory was considered by Reyes and Deere11 A material law based on a generalization 12 of the Mohr-Coulomb criterion was used. In this chapter, the formulation of material laws developed by Reyes and Deere 11 is used. An efficient analysis procedure, incorporating recent developments in finite element analysis, is developed for plane-strain conditions. To demonstrate its effectiveness, the procedure is applied to three cases, one for which an exact solution is available, another for which field observations had been made, and a third one for which a parallel study was made, using an accepted limit-equilibrium method.

Jan 1, 1970

By Haim Chiswik

IN recent years considerable attention has been devoted to the devel-opment of new commercial uses for silver, chiefly because of lowered prices and large stocks of the metal. This has led to increased interest in the phase diagrams of silver alloys. The silver-lead diagram is reported' to be of the simple eutectic type, but no measurements of the solubility of lead in silver have been made. The solubility of silver in lead has been estimated2 from diffusion experiments and resistance measurements to vary with temperature from 0.09 to 0.18 atomic per cent (0.05 to 0.10 weight per cent). Silver-rich silver-lead alloys have recently been recommended as high-strength bearing metals.3 The silver-bismuth diagram is similar.' The solubility of bismuth in silver has been estimated to be about 5.5 weight per cent on the basis of X-ray work.4 Matthiessen5 found a solubility of silver in bismuth from 0.25 to 0.50 per cent by conductivity measurements. Silver and thallium form the same type of diagram,1 with no data on their mutual miscibilities. We have studied the first two of these diagrams by X-ray methods, verifying their main features and determining the solubilities of lead and bismuth in silver at several temperatures. We also determined the solubility of thallium in silver at one temperature. The solubilities of silver in lead and in bismuth were found to be too low to be detectable.

Jan 1, 1940

By David White

THE search for potash salts in the great "Red Beds? region of the Southwest, conducted for several years by the U. S. Geological Survey, the work being carried on for a part of the time in coöperation with the Bureau of Economic Geology and Technology of the University of Texas, has resulted in the discovery, within shafting depth, of potash salts, apparently of workable thickness and commercial quality, and prob-ably of great extent. Definite information is lacking as to the exact thickness of the potash beds, the size and boundaries of the areas underlain by workable strata, and the locations of the deposits richest and most favorably situated for exploitation. Briefly to review the salient features, of the general situation: We have in the great Red Beds region of the southwestern United States, embracing portions of central Kansas, western Oklahoma, eastern New Mexico, and northern and western Texas, .a series of sandstones. shales, anhydrite beds, clays and limestones, which; through an interval of 1000 ft., more or less, carry beds of salt, estimated by Darton1 to contain over 30,000 billions of tons of rock salt. It is the greatest known salt field of the world. At some points the intercalated beds of rock salt, one of which is reported by the driller to exceed 300 ft. in thickness, aggregate, accord-ing to the drillers' records, over 1000 ft. The sedi-mentary strata are similar in composition to those carrying the potash deposits of western Europe, and they were laid down at the same time and under condi-tions which, in many respects at least, were similar The stratigraphy and character of the beds are des-cribed by Darton2 and a, part of the area and the reported aggregate thicknesses of salt are shown, with some revision after Darton, in the accompanying map Fig. 1. The assumption that in the great areas of shallow evaporation basins spread over -the vast base-level region of saline deposition in the Southwest during Permo-Triassic time, potash salts were in some places, and at different stages, thrown down in crystalline deposits associated with the beds of rock salt, anhydrite, and gypsum, is, geologically speaking, more than reason-able. They are to be expected, and the conviction that they are probably present has long been held both in the Texas Bureau of Economic Geology and Tech-nology, under Dr. J. A. Udden, and in the- U. S. Geological Survey. Accordingly, for many years, efforts to determine whether potash deposits are present in this region have been made, though under very great difficulties, such as insufficient funds for boring, hack of drilling on private initiative in the more promising regions, hack of interest at first on the part of the drillers and companies, and, hater, inadequacy both of the methods of boring and of the sampling, to reveal in definite terms the thickness-of any saline stratum of given composition.

Jan 4, 1922