Search Documents

The Institute assembled in the room of the Board of Trade, Mercantile Library Building, on Tuesday evening, May 20th, at 8 o'clock P.M, Hon. W. D. Kelley made an address of welcome to the Institute, which was responded to by President Raymond. The Council reported, through the President, that the Institute had during' the past year, held three meetings, in New York, Pittsburgh, and Boston. Thirty-nine papers of great professional value had been read, and sixty-nine members and twenty-four associates added to the Institute. The finances of the Institute were in good condition, the report of the Treasurer, Mr. T. D. Rand, showing a balance on hand of $1569.74. The report was accepted. Prof. L. Gruner, of Paris, France, and Prof. Peter von Tunner, of Leoben, Austria, having been proposed by ten members of the Institute, and approved by the Council, were unanimously elected honorary members. The Council reported the names of the following gentlemen, with recommendation for election as members or associates. They were unanimously elected. *Barker, Prof. G. F.,.....Philadelphia, Pa. Chalfant, John W.,.....Pittsburgh, Pa. *Crawford, John J.,.....Philadelphia, Pa. *Crusius, O. H.,.Columbus, Ohio. Dibble, Theo. Hoyt,.....Pottsville, Pa. Everson, John,. Pittsburgh, Pa. Field, Robt. P.,.Philadelphia, Pa. *Fisher, F. A.,.Bristol, Tenn. *Fleming, W. E.,.Pioche, Nev. *Harden, E. B ,..Philadelphia, Pa. *Harding, G. E.,.New York. Hartshorne, J.,..'Philadelphia, Pa. Haupt, H., Jr.,.Philadelphia, Pa.

Annual Meeting, Philadelphia May, 1873 THE Institute assembled in the room of the Board of Trade, Mercantile Library Building, on Tuesday evening, May 20th, at 8 o'clock P.M, Hon. W. D. Kelley made an address of welcome to the Institute, which was responded to by President Raymond. The Council reported, through the President, that the Institute had during the past year, held three meetings, in New York, Pittsburgh, and Boston. Thirty-nine papers of great professional value had been read, and sixty-nine members and twenty-four associates added to the Institute. The finances of the Institute were in good condition, the report of the Treasurer, Mr. T. D. Rand, showing a balance on hand of $1569.74. The report was accepted. Prof. L. Gruner, of Paris, France, and Prof. Peter von Tunner, of Leoben, Austria, having been proposed by ten members of the Institute, and approved by the Council, were unanimously elected honorary members. The Council reported the names of the following gentlemen, with recommendation for election as members or associates. They were unanimously elected. *Barker, Prof. G. F., - Philadelphia, Pa. †Chalfant, John W., - Pittsburgh, Pa. *Crawford, John J., - Philadelphia, Pa. *Crasius, O. H., - Columbus, Ohio. †Dibble, Theo. Hoyt, - Pottsville, Pa. †Everson, John, - Pittsburgh, Pa. †Field, Robt. P., - Philadelphia, Pa. *Fisher, F. A., - Bristol, Tenn. *Fleming, W. E., - Pioche, Nev. *Harden, E. B, - Philadelphia, Pa. *Harding, G. E., - New York. †Hartshorne, J., - Philadelphia, Pa. †Haupt, H., Jr., - Philadelphia, Pa. * Members. † Associates.

Jan 1, 1874

His face wreathed in smiles, J. Richard Lucas, Chairman of the Keynote Session, conceded that "the papers appeared to have been of some interest." This was a modest description of the opening day of technical sessions at the SME Fall Meeting and Exhibition, October 13 to 15, in Tampa, Fla. The auditorium had capacity for 800 spectators and there was hardly a vacant seat visible. The topic, Resource Development of the Fertilizer Minerals, was covered in four authoritative papers. H. S. Ten Eyck set the stage. Resources are always viewed in relation to future requirements, and these depend largely on population. If the population trend continues, the world's 3.3 billion people will increase to 6.7 billion people by the year 2000. About 70% of this increased population will be in developing areas which are not capable of supplying sufficient food and fiber for their needs. Fertilizer is a means of bridging the crop shortage. Projections of fertilizer requirements by 1970 are from 53 million to 67.5 million long tons of plant nutrient which compares with 1964 consumption of 37.7 million tons. Looking ahead to 1980, the growth continues with an estimated demand of 80 million to 113 million tons combined of N P and K.

Jan 12, 1966

By Richard W. Greene, Joel S. Hirschhorn

MATERIALS containing very large amounts of porosity, in the order of 50 to 90 vol pct, are extremely difficult to evaluate according to conventional mechanical behavior tests. This is usually a consequence of their low strength and brittleness, and the difficulty of preparing standard test specimens. A simple fatigue test has been developed and used successfully on porous nickel sheet materials requiring no specimen preparation; it could also be used for configurations other than sheet or plate. Samples of the sheet. 2 in. sq and about 0.025 in. thick, are placed in a vessel that is evacuated to about 50 f Hg by a mechanical pump. Distilled and deairated water is allowed to enter the vessel thereby filling the porosity (virtually all the porosity in these nickel ma-

Jan 1, 1970

By G. W. Tracy, R. D. Carter

A method based on an approach by Hurst' is developed for calculating water influx behavior. Using this method, superposition calculations may be eliminated. The principal diflerence between this method and that of Hurst is that, over finite intervals of time, constant oil-productton rates are assumed by Hurst whereas constant water influx rates are assumed in the presently described method. By adopting the assumption of constant water influx rate for finite time periods, a method is developed for calculating water influx behavior which lends itself to convenient combination with the material balance equation in the Schilthuis form. Above the bubble point, an equation is given for the explicit step-wise calculation of pressure history for a prescribed oil-production history. Use of this method of calculating water influx behavior should result in a considerable saving of time as compared to superposition calculations when the calculations must be made without using a digital computer. The connection is shown between the method described herein and the method developed by van Ever-dingen and Hursr2 (which requires superposition cal-culations). Also, results obtained using the two methods are compared.

By J. H. Frye, J. W. Caum

ONE of the most important methods of increasing the hardness of metals is alloying. In spite of the widespread use of alloys, the fundamental mechanism of alloy hardening is little understood. This is true even of the simplest form of alloy, the primary substitutional solid solution in which solute atoms substitute for solvent atoms at random in the crystal lattice of the latter. A fundamental understanding of the mechanism of solid-solution hardening would be important, both because of the widespread use of alloys of this type and because of the light that might be thrown on the mechanism of hardening in more complicated alloys. The present investigation covers the hardness of primary substitutional solid solutions of zinc, gallium,, germanium; and arsenic in copper. All of these are B subgroup elements from the third period of the periodic table. Cu, Zn, Ga, Ge, and As are in groups I, II, III, IV, and V, respectively and lie just to the right of the transition elements. Because of their cost, it is unlikely that Ga-Cu and Ge-Cu solutions will ever be of commercial importance, but the intent of this study has been to discover some of the fundamentals of solid-solution hardening and it has been demonstrated that such a study is far more likely to be fruitful if alloys are made up on the basis of position of the constituent elements in the periodic table than if commercially important alloys are used. Many investigations have. been made of the hardness of substitutional solid solutions, but lack of attention to purity of the metals, infrequent grain-size control, and the use of varying testing techniques have virtually invalidated any comparisons. The purpose of most investigations has been to solve immediate problems and not to solve the primary problem: Why do solid solutions usually have a greater hardness than pure metals? PREVIOUS WORK Theories have been advanced to account for the hardness of solid solutions,, but relatively little experimental work has been done. Perhaps the first experimental work of merit was that of Norbury1 on copper alloys. He showed that for several alloys there was a correspondence between the hardness of one atomic per cent solutions and atomic volume of the solutions. More recently Brick, Martin, and Angier2 have investigated the effect of various solute elements on the hardness of copper. They concluded that the hardening effect of these solutes depended "primarily on the difference in atomic volume of solute and solvent or, relatedly, upon the parameter, change of the solvent or the extent of solid solubility." They also observed the effect of these elements on hardness and texture developed by rolling and by annealing of rolled material. Austin3 examined the hardness and response to heat-treatment of various iron solid solutions. Frye and Hume-Rothery4 measured the hardness of a number of silver solid solutions containing approximately

Jan 1, 1943

By J. A. Bowknocker

NATURAL GAS was secured in the Trenton limestone near Findlay, Hancock County, in 1884, and oil in the following year. Drilling was rapid so that the production increased by leaps and bounds; in 1896, it exceeded 25,250,000 bbl., the maximum for the field. Since that time, the yield has decreased steadily and in 1921 was only 1,447,243 bbl. The territory extends as an arc of a circle from near the western end of Lake Erie southwest into Indiana, which it enters in Adams and Jay Counties. Sixteen counties are listed in Ohio but five of them combined had a new production of only 264 bbl. and they might well be omitted. Progress in the Trenton limestone field of northwest Ohio in 1923 is shown in Table 1.

Jan 3, 1924

By Daniel L. Noble

Riparian communities are those related to, or near a natural watercourse (or sometimes of a lake, impoundment, or tidewater). Generally, riparian communities contrast sharply with the dominant vegetation type in an area, for example, the willow-birch-aspen- dominated watercourse in the Black Hills with its associated beaver- muskrat-trout habitat as compared to the dominant monotype ponderosa pine forest on either side of the drainage. Riparian ecosystems are valuable for the aesthetics, namely, varied landscape; photography and art; human awareness; diversity of plant and animal life, some of which may be unique to that habitat; cover, food, and water for associated wildlife and domestic animals; for recreation; for domestic water supply; and as natural outdoor laboratories. One major negative impact on riparian communities is hazardous chemicals from effluents from agricultural, industrial, and mining- metallurgical processes. One such chemical is cyanide, long used in the processing of gold and silver, and discharged previously directly into some of our natural ecosystems. With present environmental awareness, industry and government are attempting to minimize or eliminate this contamination. Homestake Mining Company began processing gold ore in the Lead- Deadwood area of South Dakota in 1878 and has remained in production at variable activity levels to the present time. The amount of cyanide (and heavy metals) entering the ecosystem during this time can only be crudely estimated, in part because of the variability in activity and the lack of understanding and concern about environmental pollution until the 1960's. Whitewood Creek, a tributary of the Belle Fourche River which flows into the Cheyenne River and

Jan 1, 1983

By E. J. Westerman

Prealloyed powders of nickel-base superalloys were sintered to almost theoretical density in short sinterilzg times. It was ascertained that the rapid densification was caused by a small amount of liquid phase at the grain boundaries, which apparently ovriginated by incipient melting at temperatures considerably below those at which macroscopic melting of the compacts occurred. An increase in the quantity of liquid phase present during sintering-, caused by an increase in the sintering temperature, increased the densification rate, but resulted in a decrease in the room temperature tensile propevties. NICKEL-base superalloys, which presently comprise an important group of high temperature alloys, are difficult to fabricate by the forging, casting, and machining operations presently used. As it was felt that fabrication by powder metallurgical techniques might offer advantages in the production of super-alloy parts, a basic investigation of the most important process in the sequence of powder metallurgical operations, the sintering process, was undertaken on Rene 41, Udirnet 500, and Nimonic 90 and 100 powders. These alloys age harden by the precipitation of the ? Ni, rA1,Ti) phase. Nickel-base superalloys of the Nimonic type have been fabricated by powder metallurgical methods, and their mechanical properties reported in detail.' Other alloys for high temperature service which have been fabricated by powder metallurgical methods include a Co-base alloy of the Vitallium type;2,3 alloys with a Co-Ni-Fe-Cr base;4 stainless steels;5'6 Cr-W-Co alloys;" and a Co-base alloy, X-40.8 METAL POWDERS The superalloy powders investigated were: a) a prealloyed at.omized Rene 41 powder; b) a prealloyed atomized Udirnet 500 powder; c) a prealloyed atom-

Jan 1, 1962

This volume summarizes characteristics and the geological setting of porphyry copper deposits of the Western Hemisphere. Grouped by characteristics, porphyry copper deposits are described in six regions: Andean orogen, Appalachian orogen, Alaska, northern Cordilleran orogen, southern Cordilleran orogen, and the Caribbean. Each region has its own peculiarities of geologic setting, and those deposit characteristics that may be projected from one chapter to another will be used in reaching the conclusions from which to draw genetic models for porphyry copper deposits. The term porphyry in this volume denotes a type of ore deposit, rather than a rock classification. The classification of intrusive igneous rocks used in this volume is shown in Figs. 36a and 42 (pp. 103, 130). Some modern classifications suggest mineral-ratio definitions other than those used in this volume; however, most literature references cited are based on the classification shown in Figs. 36a and 42. The reader should be aware, therefore, that quartz monzonite in this volume contains from 35% to 65% potassuim feldspar and at least 10% quartz. A term used in this volume is defined where introduced within the context of a specific chapter. Distensional tectonic conditions are used in the sense of Cady (1972) in the Appalachian orogen, for example. Porphyry copper deposits are defined as large bodies of mineralized rock, usually including a porphyritic intrusive phase, that have copper sulfide minerals disseminated through them. The definition has no commercial connotation and is used strictly in a noneconomic sense to encompass the spectrum of copper mineralization associated with these deposits. Terms commonly accepted in the literature are not defined. Porphyry molybdenum and porphyry copper deposits commonly are distinguished by most economic geologists. The basis for the separation is summarized in one chapter of this volume. To permit the reader to more easily peruse the bibliography for any particular region, references will be found at the end of each chapter. The bibliography is not intended to be complete, but is designed to provide adequate minimum coverage for descriptions of deposits in the chapter concerned. Each entry is properly referenced in the text of that chapter to facilitate the reader's research into any particular topic. This volume is written from the point of view of the exploration geologist whose task it is to evaluate the structural, petrographic, mineralogic, and metallogenic characteristics of a porphyry copper deposit. The goal of the evaluation is to determine if, and where, concentrations of metals may exist in an igneous- hydrothermal system that includes the most complex set of geologic factors found in any of the many types of ore deposits. The successful porphyry copper geologist is simultaneously a petrographer, geochemist, structural geologist, and mineralogist. Some porphyry copper deposits have developed in volcanic arcs underlain by a Benioff seismic zone with a trench paralleling the arc. The most convincing example of a deposit known to have developed in an environment where subduction is an active process is the 3.3 m.y. (million years) old Dry Creek occurrence in the Aleutian arc (this volume). On the other hand, the younger deposits in the Cascades appear to have formed in a volcanic arc lacking both the Benioff zone and the offshore trench. Subduction is not widely accepted as an active mechanism for the period when the younger Cascade deposits formed. Subduction has also been questioned for deposits formed at a great distance from a plate boundary (e.g., Bingham). Regardless of the pros and cons regarding subduction, most deposits are associated with regional faults. Strike-slip

Jan 1, 1978

By M. Kashiwada

The zinc leach residues are introduced into waelz kiln to fume volatile metals and before the end of 1967, the waelz-fume containing zinc, lead, cadmium and indium was directly recycled back to the leaching process for the production of electrolytic slab zinc. However, since 1968, we have been recovering with success those valuable metals contained in the fume separately instead of direct leaching. According to the improved process, the waelz-fume, after being mixed with chloridizing agents, is fed into the rotary kiln to be roasted, wherein most of lead and cadmium content is collected as fume and most of zinc remains in the calcine. Zinc calcine thus obtained, containing 70 to 75 per cent zinc and, less than 1.0 per cent lead is sent to zinc plant for further recovery and the fume containing 40 to 50 per cent lead and 3 to 6 per cent cadmium is further processed to recover lead, cadmium and indium. The advantage of this process can be secured to the utmost when it is combined with the following subsequent treatments. (a) Blast furnace smelting of non-magnetic waelz slag to recover copper, silver and gold as matte. (b) Gallium recovering process from magnetic waelz slag. (c) Soda process of lead bearing cake produced after removing cadmium and indium from the said fume. Thus the extractions of zinc, lead and cadmium from leach residues account for 87 per cent, 72 per cent and 85 per cent respectively.

Jan 1, 1970

By T. H. Ramsey, Richard Shield

A process has been developed for fabricating thin-film resistors that are compatible with integrated circuits. Films are produced by evaporation of single refractory metals using an electron beam heating source. Resistor paths are then made using standard photoresist etching techniques. A low-temperature coefficient of resistance is obtained by control of nucleation during deposition of the film. One application of the process has been the development of a discrete resistor used for current setting in linear integrated circuits. Multiple thin-film resistors were formed on oxidized silicon substrates using molybdenum metal as a source. An evaporated protective layer of SiO2 over the resistor prevents resistance changes which might occur during subsequent high-temperature processing. Properties of a typical resistor are as follows: R = 15.7 ohm per sq, tolerance surface dimensions = 0.028 by 0.028 in., stable after 4000 hr at 0. 75 w without heat sink. THIN-FILM resistors have been investigated for many years with a large selection of usable resistors resulting from a wide variety of materials. Many of the processes necessitate a high degree of complexity but in nearly all cases the conclusions have been that the materials used in each case were acceptable provided the deposition process was reproducible and could be controlled sufficiently to give the required tolerances. It is our opinion that simplicity is still the key to thin-film resistor fabrication. In this regard, the single metal is obviously the simplest process to control, provided all the necessary properties can be obtained. The idea is not original in this laboratory by any means. Others have taken this approach.' It has been demonstrated that a fairly wide range of resistivities can be obtained by careful control of deposition parameters for any given metal, and by selection of several single metals a very broad range of stable resistors can be obtained. The transition from one metal to the next is made when a film becomes too thin for adequate process control or long-term stability. A great deal of emphasis is once again being placed on the thin-film resistor. Although they have been thoroughly studied in the past, new applications have been found that require the properties obtainable only from thin-film resistors. Integrated circuits, in general, are advancing toward higher speeds and radiation environments which require replacement of the present diffused resistors. Linear circuits in particular are requiring high-power, high-precision resistors for the more advanced applications. The particular requirements of some linear circuits are such that a discrete resistor is required. The resistor described in this paper was developed as a 15.7-ohm precision discrete resistor for use in a current regulating circuit requiring a +2 pct end of life overall tolerance, a dissipation of 750 mw, and the ability to operate over a fairly broad temperature range (i.e., a low temperature coefficient of resistance, TCR). State-of-the-art integrated circuit and silicon processing technology lends itself well to the fabrication of thin-film resistors. Not only is the resistor thin film well-suited to integration on individual circuits, but the oxidized silicon surface provides one of

Jan 1, 1969

Alpha Portland Cement Co.'s mining operations at Manheim W. Va., produce 750,000 bbl of limestone yearly, averaging 2200 bbl per working day. Thirteen parallel entries have been driven to date, each almost 30 ft high and about 45 ft wide, extending back 5000 ft to the working faces. Pitch of the seam from the lowest to the highest entries is steep enough to provide excellent year- round natural ventilation, and this, together with the size of the entries and a good bottom, has allowed face crews to drive right up to the working areas in the family car.

Oct 1, 1956

E.T. CONNER;. Scranton;. Pa-I had the honor of being associated with Mid. Griffith in an investigation of the Scranton mine cave problem several years ago; in the course of which we investigated rather carefully the bearing strength of various materials that might be utilized for, the support of over We found that there were no reliable data as to the resisting strength, for instance, of gob pillars or timber cogs or cribs, nor as to the amount of compression that might be expected under a given burden. We made a series of tests at the Fritz engineering laboratory of Lehigh University, from which we, reduced certain conclusions, subject, however, to further test before they could be definitely recommended. Onr study of the subject was later checked by a commission appointed by the Governor of the State of Pennsylvania, to investigate the same subject the subsidence of the surface, and the danger entailed thereby. The State, commission made a series of tests on a much more ambitious scale at Pittsburgh, in the laboratory of the U. S. Bureau of Mines, and their tests agreed quite closely with those that Mr. Griffith and I had made. As the result of our study, we determined that the most elastic support is the ordinary timber cog or crib, while the most rigid support is a

Jan 1, 1918

By K. E. Brown, G. H. Fancher

An 8,000-ft experimental field well was utilized to conduct flowing pressure gradient tests under conditions of continuous, multiphase flow through 2 3/8-in. OD tubing. The well was equipped with 10 gas-lift valves and 10 Maihak electronic pressure recorders, as well as instruments to accurately measure the surface pressure, temperature, volume of injected gas and fluid production. These tests were conducted for flow rates ranging from 75 to 936 B/D at various gas-liquid ratios from 105 to 9,433 scf/bbl. An expanding-orifice gas-lift valve allowed each flow rate to be produced with a range of controlled gas-liquid ratios. From these data an accurate pressure traverse has been constructed for various flow rates and for various gas-liquid ratios. A comparison of these tests to Poettmann and Carpenter's correlation indicates that deviations occur for certain ranges of flow rates and gas-liquid ratios. Numerous curves are presented illustrating the comparison of this correlation with the field data. Poettmann and Carpenter's correlation deviates some for low flow rates and, in particular, for gas-liquid ratios in excess of 3,000 scf/bbl. These deviations me believed to be mainly due to the friction-factor correlation. However, Poettmann and Carpenter's correlation gives excellent agreement in those ranges of higher density. This was as expected and predicted by Poettmann. He pointed out that their method was not intended to be extended to those ranges of low densities whereby an extreme reversal in curvature occurs.l As a result of these experimental tests, correlations using Poettmann and Carpenter's method were established between the friction factors and mass flow rates which are applicable for all gas-liquid ratios and flow rates. Definite changing flow patterns do not allow any one correlation to be accurate for all ranges of flow. INTRODUCTION The ability to analytically predict the pressure at any point in a flow string is essential in determining optimum production string dimensions and in the design of gas-lift installations. This information is also invaluable in predicting bottom-hole pressures in flowing wells. Although this problem is not new to industry, it has by no means been solved completely for all types of flow conditions. Versluys,2 Uren, et al, 3 Gosline,4 May,5 and Moore, et al,6,7 were all early investigators of multiphase flow through vertical conduits. However, all of these investigations and proposed methods were very limited as to their range of application. Likewise, many are extremely complicated and therefore not very useful in the field. Only in the last decade have any significant methods been proposed which are generally applicable. The most widely accepted procedure in industry at the present time is a semi-empirical method developed from an energy balance, proposed by Poettmann and Carpenter8 in 1952. Their correlation is based on actual pressure measurements from field wells. Accurate predictions from this correlation are limited to high flow rates and low gas-liquid ratios. Although this method will be discussed in detail later, it should be pointed out that two important parameters, namely the gas-liquid ratio and the viscosity, were omitted in their correlation. The viscosity was justifiably omitted since their data was in the highly turbulent flow region for both phases, and most wells fall in this category. The gas-liquid ratio was incorporated to some extent in the gas-density term. In 1954, Gilbert9 presented numerous pressure gradient curves obtained from field data for various flow rates and gas-liquid ratios for the determination of optimum flow strings. However, no method is presented for predicting pressure gradients except by comparison to these curves. Baxendell, et al,10 proposed a method based on Poettmann and Carpenter's procedure

By Portland P. Fox, Berlin C. Moneymaker

THE development, within recent years, of core drills capable of drilling holes up to 72 in., or even more, in diameter, has made possible an entirely new and valuable method of geologic exploration. Although little used until recently as an exploratory tool except in the United States, by the Tennessee Valley Authority and the Corps of Engineers of the U. S. Army, for the exploration of damsites, the large-diameter core drill may be used to good advantage in other types of geologic exploration. Its principal utility is that of supplementing, rather than replacing, other means of exploration. Although core is frequently recovered intact, the greatest advantage of large-diameter drilling is that the holes produced are large enough to be entered by the geologist and engineer, and thus afford an excellent means of examining undisturbed rock. The walls of the holes are smoothly cut, and in some rocks nearly or quite polished, so that the most minute details of structure and stratigraphy are clearly disclosed. Such features as faults, joints, bedding planes, weathered "seams," and beds or layers of soft materials, which are not always amenable to disclosure by cores recovered from small-diameter holes, are conspicuously displayed in the walls of large holes. Frequent reference to the drilling of large-diameter holes is made in engineering literature, but comparatively little emphasis has been placed on their value in geologic investigation. It is, therefore, intended that the present paper acquaint the geologist, as well as the engineer, with the large-diameter core drill and the technique involved in its use, and also with its advantages, disadvantages and limitations as an implement of geologic exploration. THE EQUIPMENT The equipment generally employed in the drilling of large-diameter holes consists of a trunnion-type drill head mounted on a sliding base, which allows it to slide clear of the hole and thus permit the introduction

Jan 1, 1938

By J. B. Sellers, G. R. Haworth, F. W. Brackebusch, P. G. Zambas

Results of large-scale mining experimentation carried on in Stage II of the Anvil Points Oil Shale Research Program, Rifle, Colo., are reported. After a new adit was excavated, over 500,000 tons of oil shale was extracted during a 13-month period by a modified room and pillar method. Experiments in drilling and blasting headings, benches, and crosscuts are reported. Roof-bolting procedures, loading and hauling, and ventilation design are discussed. Results of the extensive investigations carried out by the cooperative industry group and earlier work by the U.S. Bureau of Mines indicate that mining oil shale is technologically feasible.

Jan 1, 1973

By Donald J. Drinkwater, M. C. Fuerstenau

Many important contributions to the more fundamental aspects of mineral processing have been made this past year. Mular1 researched the flotation characteristics of pure zinc oxide and also samples that had been doped with Al+++ and Cu++. Correlation of the response of pure zinc oxide to oleate flotation with a calculated zpc (from solution equilibrium) suggests that adsorption of oleate ion is coulombic in nature. Doping the sample with Al+++ (which will make the ZnO more n-type) had a marked effect on the maximum value of pH at which 50% recovery was obtained at constant collector addition. That is, when 0.5 mole percent Al+++ was added, the pH for 50% recovery was reduced by about four units. Treatment with Cu++ was found to have little effect on the flotation response of zinc oxide, even for additions of one mole percent. Since the zero points of charge of the Al+++ doped powders were not measured, it was not possible to correlate flotation data of these samples directly with charge phenomena.

Jan 2, 1966

By Charles C. Fatino, Joel S. Hirschhorn

Loose compacts of strained and annealed stainless-steel powders were sintered at various temperatures and times to determine the effect of residual strains on the sintering behavior. The atomized powders were prepared by annealing, ball milling, and rean-nealing. The residual strains and domain size were determined by a Fourier analysis of X-ray diffvaction dala. The specimens were prepared by siwzultaneously sintering cylinders of both strained and unstrained powder. The evaluation of the sintered compacts included density measurements, metallographic examinations, and analyses of X- ray diffraction data. The results of these studies reveal a definite increase in sintered density and sintering rate for the strained powders. THE pressure compacting of metal powders causes deformation of the particles, mechanical interlocking, and increased contact area. After the deformation, severe residual strains remain in these particles. The subsequent contributions of these strains to the sintering process have been considered to be negligible, since the recovery and recrystallization temperatures usually occur prior to the temperature required for the sintering process. Sintering is con-sidered to be the process by which the powders are transformed into solid compacts at temperatures below their melting points. The sintering operation for stainless steel usually takes place in the range of 2050" to 2400°F (0.84 to 0.95 T,, where T, is the absolute melting point or liquidus temperature) while the temperature required for recovery is approximately 1800°F (0.75 T,). However, it has been shown for several metal powders that densification becomes significant in the range of 0.35 to 0.45 T,.' It is the purpose of this study to determine what effect residual strains have upon the sintering behavior of stainless-steel compacts. Loose compacts were selected for study in order to isolate the strain contributions and eliminate the variables inherent in sintering of pressure-formed compacts. Additional variables were minimized by using only one mesh size, one composition, one particle shape, and also by simultaneously sintering both types of powder. Very little work has been carried out previous to the present study to delineate the effect of strains on sintering behavior. Lenel et 01.2 observed that residual stresses in copper compacts caused shrinkage at comparatively low temperatures. Delisle3 loose-sintered ball-milled electrolytic iron and observed that bonding among particles began at a lower temperature as compared to the behavior of annealed powder. Increased densification of ball-milled oxide powders has also been noted.4'5 EXPERIMENTAL PROCEDURES Powder Preparation. The powder used for this study was a commercial-type 316L stainless steel made by the atomization process. A typical chemical analysis is: C- 0.025 pct Mo- 2.2 pct Cr-18.6 pct Ni-12.5 pct Fe—Balance The atomizing process is essentially the rapid freezing of liquid droplets. This nonequilibrium cooling causes coring to occur and two distinct phases are present within the solid particle, the austenitic phase and the ferritic phase. Due to the presence of this ferritic phase, the particles tended to fracture as well as become cold-worked during the subsequent ball-milling operation. (It was also found that this type of cooling produced a broadened and shifted

Jan 1, 1968

By Henry B. Estabrooks

As was true with many mining companies, the management of Tennessee Copper Co. followed with interest the successful application of AN-FO as an explosive in coal stripping, construction, open-pit mining, and finally in underground salt mines. Since Tennessee Copper's operations required about 1,250,000 lb of dynamite annually, the potential savings in explosives costs that could be realized by switching to AN-FO could not be ignored. From a cautious start, AN-FO is now being used for stoping, development work and secondary blasting in all mines of Tennessee Copper Co. AN-FO accounts for 80% of the explosives used in such work. Fragmentation, fumes, crew acceptance, and cost savings have been quite attractive without any decrease in safety.

Jan 11, 1962