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By Ming-Kao Yen, W. R. Hibbard

Various rationalizations of preferred orientations in cold worked polycrystalline metals have been based on the operation of at least two three2 five, an indefinite number, and all,6 slip systems of the type occurring in single crystals. Pickus and Mathewson3 suggested that the cold rolling texture in face-centered cubic metals could be rationalized on the basis of two or more operating slip directions symmetrically disposed about the direction of flow in such a manner that the resolved shear stress factor is equal for all operating slip systems and lattice rotations cancel each other. The importance of the direction of flow, the necessity for the operation of slip systems capable of producing the required changes in external dimensions, the maintenance of a common surface between adjacent grains and a symmetrical arrangement of the operating slip systems in order to produce an end orientation which is stable under additional deformation lead to the following rationalization of textures based on the type of slip systems operative in single crystals. The rationalization is intended to explain why certain orientations are suitable for deformational flow without a change in orientation and thus are stable end orientations or ideal texture orientations. It does not attempt to explain how the grains of a randomly oriented polycrystalline aggregate will reach this orientation. The rationalization is based on the following four postulates: 1. The ideal textures for polycrystalline aggregates are the result of reorientations of individual crystals toward the same stable end orientation at which no further reorientation will occur even during additional deformation. Since, in simple slip, the relative orientations of the stress axis and the active slip system determine the change in orientation during slip, it is considered that the orientation of the stress axis with respect to the ideal texture determines what slip systems must be active to retain the stable end orientation. Therefore the stable end orientation should be a symmetrical one around the stress axis with respect to the active slip systems such that lattice rotations resulting from slip will cancel each other and prevent a resultant change in orientation. (Rotational symmetry only—not translation, inversion, nor others—is considered here.) Thus a metal under a pure stress should develop a texture consisting of one or more of the crystallographically symmetrical directions, <100>, <110> or <111> for cubic metals or <0001>, <1010> or <1120> for hexagonal close-packed metals, parallel to the stress axis. 2. Since the active slip direction is the direction of glide during simple slip and thus the direction of maximum shear movement, in the ideal texture the active slip

Jan 1, 1949

By N. K. Chen, C. H. Mathewson

Recrystallization of aluminum single crystals after plastic extension is carefully studied in relation to the structure of the deformed matrix. The shapes of the new grains are analyzed with regard to slip planes and to the presence or absence of deformation bands. A mechanism by which the orientations of the grains are related to the parent lattice is described. EXPERIMENTS previously reported&apos; have been extended to develop some of the characteristics of the new crystals which are formed on annealing axially strained crystals whose deformational characteristics had been documented with special care. Thus, the presence of deformation bands affects the growth contours of the crystals, some of the strained crystals produced single crystals anew, and some, polycrystals, on annealing, while others merely "recovered" or "polygonalized" after the 600°C annealing treatment generally adopted in these tests. In the matter of orientational relationships between new crystals and the strained matrix, the present experiments have added little to previous experience, which had demonstrated great variety in the range of orientations encountered and no simple theory or correlation. For example, there has been ample evidence for the predominance in various face-centered cubic metals of a favored orientational relationship; viz., a rotation of 30° to 40° around a <1ll> axis, between grains growing in a matrix with a strong single orientation texture and the matrix itself.&apos;-&apos; This reorientation has been interpreted by various investigators in support of both the "oriented nucleation" and the "oriented growth" hypothesis. In the case of axially extended single crystals of aluminum, no general relationship, such as the one stated above, can be used to correlate the orientations of the recrystallized grains with that of the original crystal. Thus, Carpenter and Elama and Burgers and Basart7 were content to assume that the orientational relationships so developed were random in nature. Mathewson, however, in the Campbell Lecture of 1943 "rgued on the basis of <112> slip that a complex strain, chiefly characterized by rotation around a variable axis in the slip plane combined with a principal rotation around the pole of the slip plane, could be responsible for such devious relationships. Nevertheless, owing to the limited data now available dealing with orientational relationships between new grains and the single crystals strained in tension from which they have recrystallized, no adequate examination of the above generalization could be made. Here, there is the disturbing preliminary condition that any desired orientational relationship may be expressed by means of two rotations about mutually perpendicular axes, so the process lacks a certain critical flavor and any successful choice of axes meeting certain theoretical requirements could be replaced by another differently selected pair. With this reservation clearly in mind the process of double rotations, as previously indicated, was used to relate the orientations of the single crystals which grew out of the strained single crystalline matrix and was construed as certain evidence in favor of the theory of incongruent shearing action proposed by Mathewsons as a necessary element in the (111) slip process with close-packed metals. There is here

Jan 1, 1953

Report of the Secretary TO THE BOARD OF DIRECTORS AND THE MEMBERS OF THE AMERICAN INSTI¬TUTE OF MINING AND METALLURGICAL ENGINEERS GENTLEMEN As will be shown by the special reports of the Finance, Membership, Library, Papers and Publications, Increase of Membership, and other standing Committees, together with that of the Treasurer, the year 1927 was one in which the Institute made very satisfactory progress in a number of directions. In total numbers the membership is no larger but in revenue from dues there has been a marked increase. This has been due to the promotion to full membership of Junior Associates of earlier years, to the larger proportion that come in originally as members rather than juniors, and to the keener interest in the work of the Institute reflected in prompter payment of dues. The latter is important, since experience shows that of those who fall behind a large number must ultimately be dropped for non-payment. Conditions in the mining in¬dustries have been healthy though not booming. It has been much easier for members to find employment and meet their financial obligations but there has not been that flow of young men into mining, and hence in part into the Institute, that characterized certain earlier years. Rather the tendency toward centralization and larger industrial units has re¬stricted the number, though not the scope, of opportunities for technical men in the mineral industries. The Institute is constantly receiving resignations from members crowded out of mining into other lines of activity. On the other hand, those who remain in mining and metal¬lurgy have a greatly increased necessity for information and contacts with technology. A few years ago many superintendents and most foremen were non-technical men. Today the reverse rule obtains and shift bosses and men who occupy even lower positions in industrial units are called upon to know and to apply such an amount of technical knowl¬edge that graduate engineers are the rule rather than the exception. The curious situation has obtained that with a much smaller enrollment of students in the schools of mining and metallurgy there has been at times an actual shortage of young engineers for beginners&apos; jobs. The young men retort that the conditions of employment and pay offered in mining are not equal to those in other lines and, while it is undoubtedly true that the young engineer beginning in mining is able to start under conditions markedly better as to pay, living, and responsibility than did the men who are now leaders, they are required to know much more and have usually spent more in time and money to qualify for their jobs. The whole matter is one which warrants much more attention than has been given to it. For the Institute it is important since the young men

Jan 1, 1923

By J. H. Fletcher, S. M. Cassidy

Air has been cooled, heated, washed, humidified and dehumidified for many purposes and in many industries. At a number of metal mines air is conditioned to reduce the high humidity and unbearable heat found in deep workings, and at some mines air is washed to allay siliceous dust. Steam is introduced into the intake air at many coal mines, particularly in winter, for the purpose of keeping loose coal dust so moistened that the hazard of an explosion is lessened. This paper will describe a further successful application of air conditioning in a coal mine, where, for over three years, all intake air has been cooled to a constant temperature for the sole purpose of preventing roof falls. Effect of Warm Weather on Mine Roof It is generally known by mining men that some, if not all, coal mines have more trouble from bad roof during the warm summer months than in winter. Also, it has been observed that roof on intake airways is usually worse than on the return entries, after the air has circulated through the mine. Some mines and some coal seams are much more affected than others. In the Clinton district of Indiana, the No. IV coal seam has a good, firm, gray shale roof except during the summer months, when it deteriorates badly and falls in small slabs 1 to 6 in. thick. Timbering is not very efficacious during this period because in time the roof will shear around the supporting prop or crossbar and either dislodge the timber or leave it supporting only a few inches of crumbly shale (Fig. 1). This action is renewed each summer, choking airways with fallen slate, tearing down trolley wires, hampering haulage, endangering men and adding considerably to the deadwork cost. Only when mines have been worked for a period of years and have been advanced a long distance from the shaft do the active workings become comparatively free of this trouble, and even then the intake entries are still a source of much deadwork. Such was the annoying situation at the mine of the Saxton Coal Mining Co. operated in the No. IV coal just north of Terre Haute, Ind. During the months of warm weather it was possible to stand at any quiet spot in the mine and within 10 min. hear at least two or three falls,

Jan 1, 1931

INTRODUCTION Conditions for formation of porphyry copper deposits appear to have been propitious in the Appalachian orogen from the end of Precambrian into Middle Ordovician, and again from Middle Devonian into Mississippian. In the Appalachians we can now record the evolution of a porphyry copper province within a developing orogen, one that reached metamorphic and structural maturity by the end of Devonian. Fig. 15, after Irwin and Coleman (1972), locates that portion of the Appalachian orogen included in this study, and Fig. 16 illustrates general geology of the area. Deposits mentioned in Table 3 and in the text are shown in Fig. 16. Data presented summarize personal observations by the author, published descriptions of specific areas noted in the bibliography, and abstracts from Provincial assessment files. Sources of previously published data are acknowledged. Few comprehensive descriptions of individual porphyry copper deposits in this area exist, so much of the data presented is new to the literature. Porphyry mineralization has, for this chapter, been restricted to porphyry copper de- posits, although porphyry molybdenum de- posits (Clark, 1972) are also shown in Fig. 16 (Hollister, et al., 1974). Copper- molybdenum and tungsten-molybdenum skarns are also omitted to simplify discu sion, though each is known in the area studied. Gaspe Copper is included, however; min- eralization in this deposit is present in the intrusion as well as in the skarn adjacent (Bell and Scott, 1954). Porphyry deposits listed in Table 3 are included because of some important feature, although other deposits have been reported (e.g., Kirkham and Soregaroli, 1975 ) . Clearly, no table now compiled could be complete. The pace of exploration insures that new occurrences will probably be found. Summaries of features exhibited by intrusions shown in Table 3 should remain valid, however, since they appear representative and are based on an adequate number of deposits in the area studied. Paleozoic porphyry copper prospects (shown in Fig. 16) are more common, apparently, in the northeastern part of the orogen, rarely having been found south of Catheart or west of the Logan Line. Occurrences of molybdenum and other associated lithophile elements are, however, known to the south and west as well as further north. Killeen and Newman (1965), King (1970),

Jan 1, 1978

By C. D. Demond

In reverberatory smelting, fuel is the chief item of expense, as it commonly is in processes using large percentages of it. Hence the most suitable supply is eagerly sought; that is, the supply which, in the end, yields the greatest net profit. The better grades are not infrequently bought, even at an advanced price, because they are apt to be decidedly more economical. High price, of itself, however, is no merit, for freight is generally the largest part of the cost of fuel, and the nearby supply may yield as high efficiency as that from a greater distance. If a poorer grade is reasonably good, and if its cost is low enough to more than offset the decreased technical efficiency, it is of course the more suitable. Any smelting operation depends for both efficiency and economy on raising the furnace atmosphere considerably above the "critical" temperature; that is, above the temperature at which smelting is completed. If this temperature is not exceeded, smelting stops, no matter how much coal is burned; and the real value of a fuel depends on the number of degrees that the temperature is continuously kept above this point. For example, if one fuel maintains 2,500" F. and another only 2,100 F., while the "critical" temperature is 2,000" F., the first is worth at least five times as much as the second, although the increase above atmospheric temperature is only one-fifth more in one case than in the other. This "margin of temperature" above the smelting point is much more significant than the total number of heat units developed from the fuel. The case is parallel to that of water flowing from a pipe. The reservoir may contain a billion gallons of water; but, even though the fluid has come to the nozzle, not a drop will run out, where it can be of practical use, unless the level in the reservoir is higher than the nozzle; and the speed and volume of flow depend on how much higher the level is in the reservoir than at this point. If the temperature in a furnace is not above the critical level there will be no slag to flow over the skimming plate, even though there are enough heat units to bring an unlimited quantity of charge up to the point of slag formation; and just as the value of a water supply for the purpose of putting out a fire depends largely on the effective head, so the difficulties of furnace management

Jan 1, 1915

By G. L. Oldright

THE upper limit of richness of concentrates that can be smelted by means of the blast furnace without added diluents is fixed by the opera-tion of sintering. A sinter feed with normal gangue constituents, con-taining more than about 50 per cent of lead, tends to fuse; as a result, air does not come sufficiently into contact with the sulphides at roasting temperatures, and sulphur elimination is poor. Since most lead con-centrates now contain 55 to 80 per cent lead, it is necessary to add diluents to lower the grade of such sinter feed to about 50 per cent or less. This not only entails the expense of providing barren diluents when adequate diluents containing precious metals are not available but also appreciably lowers the capacity of the blast furnace to produce lead and increases slag losses. Attempts to desulphurize rich lead concentrates by methods other than sintering have not proved successful. Flash roasting, for example, converts much of the lead sulphide to lead sulphate rather than to oxide. However, this suggested the possibility that deliberate flash roasting of the concentrates to sulphate, followed by sinter roasting of the resulting product, might prove promising, particularly inasmuch as the elimination of sulphur from lead sulphate requires heat alone and not contact with atmospheric oxygen. The sintering of lead sulphate products has additional interest because important amounts of such products are now treated by lead smelters. Considerable quantities of lead sulphate are present in rich lead flue dusts and other by-products; lead-chamber sulphuric acid plants and other

Jan 1, 1940

By Leslie F. Tedsen, Alan E. Flanigan, John E. Dorn

It is necessary occasionally to use aluminum-alloy sheet where moderately elevated temperatures are encountered. Considerable attention has been directed toward determining the influence of "artificial aging" on the room-temperature properties of the precipitation-hardenable alloys, as testified by numerous company reports and by references I to 4. Investigations on the properties at elevated temperatures are few, however, and have not always covered the range of times and temperatures of greatest interest. The present investigation was instituted to overcome this deficiency. The work was done for the Office of Production Research and Development of the War Production Board, under the supervision of the War Metallurgy Committee, as a part of the "restricted" Project NRC-548. It has been released for publication by the Office of Production Research and Development. AS is well known, the high-strength aluminum alloys achieve their remarkable properties as a result of precipitation-hardening. In production they are subjected to a solution heat-treatment followed by quenching, to retain the supersaturated solid solution. The solution treatment is followed by "aging" (precipitation-hard- ening) either at room temperature or at a suitable elevated temperature. A considerable increase in tensile and compressive yield stresses results from precipitation at room temperature ("natural aging"). Through the elevated-temperature process ("artificial aging") it is possible to obtain values of yield stress considerably higher than those attainable by natural aging. The increase in yield stress is accompanied by a smaller gain in ultimate tensile stress and by a decrease in elongation. During the first stages of artificial aging the yield stress increases steadily until it reaches a maximum value. In this condition the material is said to be "fully aged." Further exposure results in "averaging," attended by a steady decrease in yield stress. In the production of the artificially aged materials, temperatures and times are selected to achieve full aging. The following important characteristics are associated with the process: 1. The higher the temperature, the more rapidly is the fully aged condition attained. :7

Jan 1, 1946

By Etienne A. Ritter

The Evergreen mine, located at Apex, in the northern part of Gilpin county, Colorado, has opened a very peculiar and interesting copper-deposit, in which both bornite and chalcopyrite occur as rock-minerals. The country-rocks are crystalline schists cut by dikes of granu-lite and of pegmatite. At the Evergreen property they have been cut by a dike of a uew kind of eruptive rock, to which I have given the name " Evergreenite." The rock is composed of quartz, alkali feldspars, orthoclase and albite (often interlocked as microperthite), with augite of the ægirine variety and long needles of enstatite and diallage. For reasons stated below, I believe the dike to be of Tertiary age. It is easily traced on the surface of the ground, from a point in the bottom of Pine creek, about a mile below Apex, to the top of Nevada hill, 1,500 ft. beyond and 600 ft. above it. (See Fig. 1.) It varies from 3 to 12 ft. in width, and is bounded on both sides by contact-zones about 60 ft. wide, in which the crystalline schists have been changed into pseudo-quartzites or pseudo-gneisees, according to the injection of an excess of quartz or of feldspars through the special layer of the schists. The most interesting feature is the presence of the pyroxenes, which are always found, though in very variable proportions from place to place, in the layers of these metamorphosed crystalline schists. The dike has torn from its walls a large number of fragments of the wall-rock. It must have been in a viscous state when that happened, because these fragments of the wall-rock do not show any sign of resorption or of assimilation by the magma. In places they are so distinct and so numerous that the rock looks to the naked eye like a pseudo-breccia, of which, never-

Jan 1, 1908

By H. W. Morse

The experimental work on the oxidized copper ore at the New Cornelia mine at Ajo, Ariz., ended on Jan. 12, 1916. On that date final decision was made on the general nature of the process to be used in the 5,000-ton leaching plant, and on many of the details, as far as experience on a 40-ton scale could decide them. With the approval of the Board of Directors and the General Manager, John C. Greenway, we have compiled what seem to be the most interesting data on the results obtained during the experimental period. The most important part of the data resulted from the operation of a 1-ton and a 40-ton plant at Ajo. Experimental work on Cornelia oxidized ore dates back to April, 1912, and has been going on nearly continuously since that time. A good many variations from the original idea have been tried, but the process finally decided upon is in principle and in all of its details a simple one. The history of the leaching work on this ore has been brought down to about a year ago in papers presented to this Institute by Stuart Croasdalel and Dr. L. D. Ricketts.2 The present paper will, therefore, deal principally with the results obtained during the last year of the work. Preliminary Tests by Mb. Croasdale Preliminary tests were begun by Stuart Croasdale in July, 1912. A number of important points were definitely decided by his work. Among these were: 1. New Cornelia oxidized ore, not very finely crushed (to about 2-to 3-mesh) showed good extraction with 5 per cent. sulphuric acid. It appeared that better than 80 per cent. extraction could be expected. 2. The consumption of acid for this extraction was not prohibitive. It was apparently 3.5 to 4 1b. gross per pound of copper recovered.

Jan 1, 1917

By Charles Y. Clayton

The shank, to give good service, should not upset nor should it cause excessive wear on the various parts of the machine. To fulfill these requirements, the steel must have a certain hardness—that is, resistance to deformation. The hardness is expressed in conventional terms, as Brinell or scleroscope number. Before deciding on the hardness that is proper, several factors should be considered; the most important are: type of drill steel used (whether hollow or solid), length of steel, nature of ground, air pressure, and hardness of hammer or anvil block (usually 600 Brinell). These are not all, but they are the most cogent ones. Without doubt, it would be better to use a shank that is too soft than one that is too hard. Most satisfactory service will be obtained from shanks that are just hard enough to resist any tendency to upset. To express the proper hardness in terms of Brinell numbers would mean a great many tests over a long period of time, or a study of drill steels that are being used successfully in the various districts. To obtain some information along this line, the persons making this investigation requested, a number of companies to send to them drill shanks that had been given the usual treatment at that mine. The results of the hardness tests are given in Table 1. The hardness values given in Table 2 are those of shanks known to have been quenched in water and drawn. These results show that where water quenching and drawing are in vogue the hardness is rarely under 400 Brinell.

Jan 1, 1923

By J. F. Fidiam, T. F. Ford, A. G. Loomis

It is only within the past 10 years that serious attempt appears to have been made to improve rotary drilling fluids by the application of the principles of colloid chemistry, although the use of chemicals to control the rheological properties of clay slips has long been known in the ceramic industry. The main difficulty apparently lay in the lack of a complete analysis of all of the functions of a drilling fluid in the drilling of the well, together with the lack of adequate consideration of how colloid science could be applied to secure these ends, and particularly how apparent antithetical properties of the fluid could be compromised. Thus one analvsisl of the many requirements of a drilling fluid proved conclusively that the viscosity should be low, in order that cuttings and entrained gas might be eliminated effi-ciently in the settling ditch, while the loss in carrying capacity accompanying low viscosity could be regained by increasing either the density of the mud or the upward velocity of the mud stream in the annular space of the well, and the danger of sticking of the drill stem due to rapid settling in case of enforced suspension of drilling operations could be eliminated by enhancing the thixotropic properties of the fluid. The desired properties of the drilling fluid having thus been established, it was a natural step to treat the fluid with vis-cosity-reducing chemicals, such as salts of weak organic acidsl for example, sodium tannate or gallate—and to adjust the pH to the alkaline side to such a degree of thixo-tropy as would give low viscosity and low yield point under the conditions of flow prevailing in the settling ditch, but rapid gelation and high yield point when quiescent in the annular space during shutdowns. In fact, flow in the settling ditch should be just short of turbulent while flow in the well, together with the flow of mud past the cuttings, is practically always turbulent. The use of chemicals other than those mentioned, such as Calgon (sodium hexametaphosphate) and certain other phosphates together with sodium tannate, has now become standard practice and it is the consensus that this method of treatment has proved to be an important step in the development of the art of drilling oil wells. It is safe to assume that the application of colloid chemical principles can also help in solving other outstanding problems of drilling fluids, such as the development of cheaper and more efficient viscosity reducers ; the development of chemicals that do not lose their effectiveness in a short time during drilling operations; the finding of chemicals to preserve the plastering properties of muds when concentrated brines are encountered or in drilling through salt beds; improvement in the plastering properties of poor muds by further defloc-culation, and, conversely, the prevention of excessive deflocculation of certain marine shales sometimes encountered; the preparation of muds suitable for the successful drilling of heaving shale formations; the finding 0f chemicals to treat the mud to prevent or to diminish lost circulation; the development 0f muds that will not impair 6

Jan 1, 1941

By Benjamin L. Miller, Charles H. Breerwood

From earliest recorded times, limestone has been employed in the industrial life of peoples of all sections of the world where it exists. It is widely distributed and therefore has been available in almost every country and has been employed for a variety of purposes. Its earliest use was for buildings, since it is more easily quarried and dressed than most other kinds of rocks and so could be utilized by early inhabitants, poorly equipped with tools. The next use was in the manufacture of lime, which was employed by the ancients in mortar. These two uses of limestone are still all important, but they have been overshadowed in scores of regions by literally hundreds of new applications for raw limestone or products made from it. Anyone familiar with modern manufacturing processes can quickly call to mind many industries in which limestones are essential, and new uses are continually coming to notice. Any enumeration would probably be incomplete and soon out of date. Origin of Limestone Disregarding details and unusual types concerning which often there is insufficient evidence and considerable difference of opinion, limestones have been formed by the precipitation of calcium carbonate from solution through the action of organisms, both plants and animals, or in a limited number of instances by chemical reactions without the intervention of living forms. Some of the organisms extracted the calcareous material in order to build up hard structures, either as bony skeletons or as coverings (clams, snails, etc.), whereas others in their life functions emitted substances that resulted in the precipitation of the soluble constituents outside the organisms themselves. In some instances the organisms utilized only calcium carbonate but in some cases other compounds as well were precipitated. Various materials have been found in the hard parts of animals, and for that reason it is almost impossible to find a pure natural limestone; that is, one composed entirely of CaCO3.

Jan 1, 1938

By E. A. Anderson, P. W. Ramsey, E. J. Boyle

Only a few zinc-rich alloys are in commercial use today, and these depend largely upon solid solution effects for their desirable properties. Typical examples are rolled alloys containing about 1 Per cent of copper, with Or without additions of elements such as magnesium, and die-casting alloys containing about 4 Per cent of aluminum with small amounts of magnesium and sometimes copper." A number of elements are capable of forming alloys with zinc, Which do not enter into solid solution except in limited degree. The Present Paper considers One such system, zinc-titanium, in which alloys having potentially useful properties in the rolled form were found. Zinc-titanium System The zinc-rich portion of the zinc-titanium diagram, as determined by standard methods in this laboratory,3 is shown in Fig. I. The portion of the diagram of significance in the present work extends from 0 to about 0.5 per cent titanium. Gebhardt4 places the eutectic at 0.45 per cent, but the evidence in favor 01 the composition given in Fig. I is considerable. The solid solubility of titanium in zinc is very low indeed and possibly places these alloys in a somewhat different category from the commercial alloys previously mentioned. Alloy Preparation All of the alloys used in this work were prepared with titanium metal of 98.9 per cent purity. In most cases high-purity zinc (99.99 per cent) was used but sufficient work was done later to show that zinc of about high-grade composition would yield approximately equal results. Best practice in alloy manufacture seemed to be to prepare a zinc-titanium hardener by adding about 4 per cent of titanium metal to molten zinc and holding under a boric acid cover, with frequent stirrings, at 750°C, until the titanium had dissolved. The desired titanium content could readily be obtained in the final alloy by adding the calculated amount 01 this hardener. The alloys proved to be quite stable in composition, unless overheated, and, with reasonable temperature control, required no cover or flux to prevent loss of titanium content by oxidatioll, Hot-rollig Tests Three alloys containing, by analysis, 0.05, 0.12, and 0.23 per cent titanium were selected for preliminary study. Slab cross sections a a marked grain refinement* (Fig. 2) in the two alloys of highest titanium content. Cast unalloyed zinc has a columnar grain structure similar to that shown for the alloy of lowest titanium content but without the scatter of small equiaxed grains at the center.

Jan 1, 1944

By Robert Wamsley, W. E. Jones

ONE of the earliest problems in the life of any community is the provision of an adequate supply of water sufficiently free from all types of contamination to be suitable for domestic purposes. Generally speaking, the location of most communities is determined to a great extent by the availability of an adequate supply of satisfactory water. For a mining camp, that consideration cannot be foremost. Here, the ore takes first place, and the men who mine it must do the best they can under the existing conditions. If there is no local source of water, it must be brought from some distant source or must be found by sinking shafts or drilling wells. Fortunate indeed is the mining company that discovers a commercially valuable ore deposit beside a never failing creek full of pure water, with sufficient water rights available, because the acquisition of water in any other manner nearly always involves not only a considerable period of time but the expenditure of considerable money. The experience of Climax Molybdenum Co. demonstrates the measures that sometimes are necessary in order to provide a suitable supply of water. The Climax mine and mill are on the Continental Divide, about 13 miles northeast of Leadville. The elevation of the domestic part of the camp varies from a minimum of 11,320 ft. to a maximum of approximately 11,550 ft. above sea level, and, as is common at such altitudes, the near-by streams that might be suitable for a water supply are small and intermittent, usually flowing only during the summer months. The only streams of any size in the immediate vicinity of Climax are the Ten Mile and Arkansas Rivers. The headwaters of Ten Mile River are on the Company&apos;s property, and its water has been used for the domestic supply. The headwaters of the Arkansas River are about 2 miles distant and have not been used as a source of supply by the company. During the past 11 years of the production of molybdenum at-Climax, the number of families living there has increased from about 45 to 283, and the population has increased from about 200 to 1200 persons. Consequently, the capacity of the water-treatment facilities, and the amount of water available, had to be increased to meet the requirements of the camp. As early as 1932 it was recognized that the water in Ten Mile River would not continue to be adequate for domestic purposes and after considerable discussion it was decided to drive a drift through the major fault in an effort to find additional water. This drift was completed in 1935 and tapped sufficient water to make the supply adequate. This water was treated in a tank underground, where lime was added, and was then piped into the domestic supply lines. At about the time this line was completed, the presence of fluorine in harmful concentrations was discovered in the water. This problem was submitted to the International Filter Co. and in November 1937 a plant of its design was put in operation for treating the water to remove the fluorine. This plant proved entirely successful,

Jan 1, 1945

By Charles H. Breerwood, Benjamin L. Miller

From earliest recorded times, limestone has been employed in the industrial life of peoples of all sections of the world where it exists. It is widely distributed and therefore has been available in almost every country and has been employed for a variety of purposes. Its earliest use was for buildings, since it is more easily quarried and dressed than most other kinds of rocks and so could be utilized by early inhabitants, poorly equipped with tools. The next use was in the manufacture of lime, which was employed by the ancients in mortar. These two uses of limestone are still all important, but they have been overshadowed in scores of regions by literally hundreds of new applications for raw limestone or products made from it. Anyone familiar with modern manufacturing processes can quickly call to mind many industries in which limestones are essential, and new uses are continually coming to notice. Any enumeration would probably be incomplete and soon out of date. Origin of Limestone Disregarding details and unusual types concerning which often there is insufficient evidence and considerable difference of opinion, limestones have been formed by the precipitation of calcium carbonate from solution through the action of organisms, both plants and animals, or in a limited number of instances by chemical reactions without the intervention of living forms. Some of the organisms extracted the calcareous material in order to build up hard structures, either as bony skeletons or as coverings (clams, snails, etc.), whereas others in their life functions emitted substances that resulted in the precipitation of the soluble constituents outside the organisms themselves. In some instances the organisms utilized only calcium carbonate but in some cases other compounds as well were precipitated. Various materials have been found in the hard parts of animals, and for that reason it is almost impossible to find a pure natural limestone; that is, one composed entirely of CaCO3.

Jan 1, 1938

By P. W. Ramsey, E. J. Boyle, E. A. Anderson

Only a few zinc-rich alloys are in commercial use today, and these depend largely upon solid solution effects for their desirable properties. Typical examples are rolled alloys containing about 1 Per cent of copper, with Or without additions of elements such as magnesium, and die-casting alloys containing about 4 Per cent of aluminum with small amounts of magnesium and sometimes copper." A number of elements are capable of forming alloys with zinc, Which do not enter into solid solution except in limited degree. The Present Paper considers One such system, zinc-titanium, in which alloys having potentially useful properties in the rolled form were found. Zinc-titanium System The zinc-rich portion of the zinc-titanium diagram, as determined by standard methods in this laboratory,3 is shown in Fig. I. The portion of the diagram of significance in the present work extends from 0 to about 0.5 per cent titanium. Gebhardt4 places the eutectic at 0.45 per cent, but the evidence in favor 01 the composition given in Fig. I is considerable. The solid solubility of titanium in zinc is very low indeed and possibly places these alloys in a somewhat different category from the commercial alloys previously mentioned. Alloy Preparation All of the alloys used in this work were prepared with titanium metal of 98.9 per cent purity. In most cases high-purity zinc (99.99 per cent) was used but sufficient work was done later to show that zinc of about high-grade composition would yield approximately equal results. Best practice in alloy manufacture seemed to be to prepare a zinc-titanium hardener by adding about 4 per cent of titanium metal to molten zinc and holding under a boric acid cover, with frequent stirrings, at 750°C, until the titanium had dissolved. The desired titanium content could readily be obtained in the final alloy by adding the calculated amount 01 this hardener. The alloys proved to be quite stable in composition, unless overheated, and, with reasonable temperature control, required no cover or flux to prevent loss of titanium content by oxidatioll, Hot-rollig Tests Three alloys containing, by analysis, 0.05, 0.12, and 0.23 per cent titanium were selected for preliminary study. Slab cross sections a a marked grain refinement* (Fig. 2) in the two alloys of highest titanium content. Cast unalloyed zinc has a columnar grain structure similar to that shown for the alloy of lowest titanium content but without the scatter of small equiaxed grains at the center.

Jan 1, 1944

By M. Prats, D. G. Russell

The performance of a well in a bounded, layered reservoir with interlayer crossflow has been investigated mathematically. The system studied comprises a centrally located well in a bounded cylindrical reservoir composed of two layers of contrasting physical properties. The reservoir contains a single fluid of small and constant compressibility. In the case of a well producing at constant pressure, the production rate of the crossflow system declines exponentially after the early transient behavior dies out. For wells which produce with constant rate, the pressure-time relationship is linear following the transient. For very early production time, the production rate of the two-layer crossflow system behaves as that of the two-layer stratified system (the case in which the layers are in communication at the well only). Except for early time, in most practical cases the performance of a two-layer reservoir with cross-flow can be duplicated by that of a single-layer reservoir. The equivalent single-layer reservoir must have the same pore volume and the same drainage and wellbore radii as in the two-layer case. In addition, the equivalent reservoir must have a "kh" (permeability x thickness) product equal to the sum of the "kh" products of the respective layers in the crossflow system. If the porosity and permeability distributions are known, the production and pressure behavior of a well with and without crossflow can be predicted. From a comparison of the observed pressure or production performance of a well and the theoretical behavior, the occurrence of interlayer crossflow can be detected. INTRODUCTION When flow is possible across the bedding plane from a low-permeability layer into an adjacent layer of moderate or high permeability, the earlier depletion of the more permeable layer will cause such flow to occur. If this situation exists, the oil recovery from tight layers can be appreciable; thus, the economic ramifications of interlayer crossflow are apparent. The possible importance and extent of flow between adjacent and connected layers — whether resulting from capillary, gravitational, or viscous forces — have been the subject of considerable speculation for many years. Jacquard1 presented a rigorous analysis of the crossflow due to single-fluid expansion occurring between two adjacent and connected layers when the well produces at constant rate. His presentation was entirely mathematical, however, and no numerical results from evaluation of the mathematical solutions were presented. Our objectives in the preparation and presentation of the present paper are essentially twofold— (1) to analyze the behavior of a well which produces a single compressible fluid from a bounded, layered reservoir with interlayer crossflow, and (2) to present practical numerical results and simplified formulas to facilitate engineering analysis of reservoirs with crossflow. The constant-terminal-pressure case was analyzed rigorously, whereas the constant-terminal-rate case was treated only for semisteady-state conditions. DESCRIPTION OF THE IDEALIZED TWO-LAYER RESERVOIR The reservoir to be studied is assumed to be bounded and cylindrical in shape, with a completely penetrating well at its center. The reservoir is composed of two adjacent horizontal layers between which fluid is free to flow. Each layer is assumed to be homogeneous, isotropic and completely filled with a fluid of small and constant compressibility. The total thickness of the reservoir is small enough

By W. C. Phalen

INTRODUCTION NOBODY will dispute the fact that the conservation in every legitimate manner of our valuable high-grade phosphate-rock deposits is a present-day problem of importance. The table and curve, given herewith, show. that during the past 10 years the exportation of high-grade rock has averaged very close to half the total output of the entire country. The bulk of this exportation is from Florida, for obvious reasons. It is plain that the deposits in this State, more particularly, are being wastefully depleted under a system of selecting the cream of the product for exportation to Europe, leaving the comparatively low-grade rock, running from 65 to 70 per cent., and under, in bone phosphate of lime, for our own n fertilizer manufacturers to work up when all the best rock is gone. In this paper the writer has endeavored to make a point of describing in some detail the important methods of production and conservation in Tennessee. These ought to prove of educational value to our American agriculturists and fertilizer manufacturers, and should result in a demand for the highest-grade rock, both for direct application to the soil and for use in making acid phosphate. It is certainly evident that the European

Jan 10, 1916

By A. U. Seybolt

The pressure-temperature relations required to maintain the existence of Si3N4 in silicon-iron of 0.44-11.7 pet Si have been partially explored. The critical data obtained have allowed the calculation of some thermodynamic quantities, and have shown evidence of an order-disorder two-phase field extending at 800°C from about l pet to 5.5 pet Si. THE presence of silicon nitride in electrical sheet, nominally about 3 1/4 pet silicon, balance iron, has been described by several authors&apos;" but there has been some discrepancy among them regarding the identity of the nitride. Also, little has been reported on the quantitative thermodynamic prop- erties. In the work to be reported here, the nitride has been found to be more stable than described by Corney and Turkdogan." Several silicon nitrides have been described in the past, including SiN, Si3N4 and Si2N4 (see, for example, Abegg6 and Pascal7). However, the literature on nitrides other than Si,N, is all very old. No recent investigators using the more powerful tools available today have reported the presence of any nitride other than S3,N4. W. B. Hicke and L. R. Brantley8 in 1930 determined the dissociation pressure of Si3N4 which they made by reacting nitrogen

Jan 1, 1959