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By John P. Norton

Microcrystalline silica has been mined in Illinois from the Clear Creek Formation since the turn of the century, especially in the area around Tamms in Alexander County, in the southernmost part of the state. This silica is consumed mainly by the abrasives and coatings industries, but is also sought after for many filler/extender uses. Production has grown with the economy with several new applications overshadowing traditional markets in recent years. Many of these applications are directly or indirectly related to energy saving factors. As a result of the "energy crisis" and "resin crunch," fillers have received a great deal of renewed attention as a desirable way of stretching the available resin supplies. With feedstocks in short supply and shortages existing in the entire petrochemical industry, the use of bulk materials to improve and extend existing resin is becoming an every increasingly important facet of plastics and coatings technology. Silica is the choise of fillers in applications where inertness, hardness, and low absorption are necessary characteristics. Microcrystalline silica has the additional advantage of being relatively easy to grind because the crude ore is a friable rock composed of tiny crystallites, many less than 0.1 u in diameter. Grinding represents a significant energy input in the production of silica flours. With energy costs increasing rapidly, comparable grades of silica flour made from microcrystalline silica have advanced less in price and it is expected this trend will continue in favor of the microcrystalline silica.

Jan 1, 1978

By C. M. St. John

INTRODUCTION The stress redistribution accompanying the excavation of a deep tunnel may induce failure of the rock. The role of the support system is to control the extent of the failed region and hence to limit closure of the tunnel within an allowable amount. In such circumstances, the design of the support system is generally based on the Ground Reaction Curve (GRC). The GRC is the relationship between the support pressure and the induced displacement at the tunnel wall for a circular tunnel under hydrostatic loading. In the calculation of the GRC (see Brown et al. (1983) for an exhaustive list of reference), the rock is generally treated as an elastoplastic material characterized by cohesive-frictional yield strength and by dilatancy during plastic deformation. A recent analytical development (Detournay, 1983) has allowed the generalization of the GRC concept for some cases of non-hydrostatic in-situ stress fields (Detournay and Fairhurst, 1982). As an application of that development, this paper describes design charts that provide powerful means of performing parametric analysis for tunnels subject to non-hydrostatic loading. BACKGROUND The in-situ stress in a plane perpendicular to the tunnel axis can be decomposed into mean and deviatoric components, Po and So (see Fig. 1). Since it is assumed that the rock is characterized by a Mohr-Coulomb yield strength, the deviatoric invariant So must be less than the limiting value Sl0 given by

Jan 1, 1984

By Y. Astafyev

In applying computers at the enterprises it is necessary to develop an open-pit model which completely corresponds in its structure, properties and characteristics to real open-pit mining. This model is used for controlling open-pit operations which ultimately define the system controlling ore reserves. The preparation and reserving of the latter are highly expensive and labour-consuming, therefore the investigations are aimed at developing the ore reserve control system which is capable to provide open- pits with the necessary ore reserves on the basis of equipment relibility characteristics, and thus helps to solve the ore reserves problem which is to define their optimum dimensions under conditions of stochasticity of production processes. In accordance with the tasks of the investigation it may be conventionally divided into three parts. The aim of the first part is to develop a structural open-pit system model consisting of a set of elements which are represented here by drill-rigs, shovels, trucks, unit trains, plant receiving bins and dumps (Fig. 1). The combination of similar elements makes up technological components the sequence of which forms simple systems. The latter, in their turn, grouping according to the type of mined rocks and inter- acting in parallel, form the "Stripping" and “Mining” subsystems. In addition to this, there is the "Ore Reserves" subsystem which serves as a "store" and includes opened-up, prepared and ready for extraction ore reserves.

Jan 1, 1977

MONDAY, FEB. 17 9.00 A.M. to 9.00 P.M. Registration at Institute Headquarters. 9.00 A.M. Meeting of Committee on Development of the Activities of the Institute, Room 905, 9th Floor. 10.00 A.M. Simultaneous Sessions of Institute of Metals Division, Room 2, 5th floor. Industrial Organization, Room 1, 5th Floor. 12.30 P.M. Luncheon at Headquarters, 5th Floor. 2.00 P.M. to 4.25 P.M. Simultaneous Sessions of Institute of Metals Division, Room 2, 5th Floor. Industrial Organization, Room 1, 5th Floor. Petroleum and Gas, Room 905, .9th Floor. 2.30 P.M. Sightseeing trip by automobile for the ladies. Among the points visited will be: The American Museum of Natural History. The Episcopal Cathedral of St. John the Devine. The Spanish Museum. The American Geographical Society. The American Numismatic Society. The visits will be followed by Tea. 4.30 P.M. Memorial Service to Dr. Rossiter W. Raymond, Auditorium. 8.30 P.M. Smoker, 5th.floor.

Jan 2, 1919

ALEXANDER, JOHN S, M,'74-6,'81-3 *ASHBURNER, C A, M, '85-7 ASMUS, GEORGE, Dl, '78-80 BACON, D H , M, '00-2 BAYLES, JAMES C , M,'80-2,'91-3 P, '84-5, V,'88-9 BIRKINBINE, JOHN, M, '83-5, V, 'S7-J, P, '91-2 BLAIR, THOMAS S , M, '74-43 BLAKE, WILLIAM P , V,'71-4,'76-7,'05-6 *BLANDY, JOHN F, V,'71-3,'78-9 BLOW, A A, C, '05-7 BOWIE, A J , JR, V,'93-4 *BRAMWELL, J H , A1, '89-91 BROOKS, THOS B , M, '72 BRUNTON, D W , V, 97-8 BUCK, STUART M , M, '83-5 *BURDEN, JAMES A, V,'80-1 BURNHAM, WILLIAM, M, '82-4. CAMPBELL, H H, M, '93-5 CHAMBERLAIN, H S , V, '96-7 CHANNING, J PARKE, V,'08 CHRISTY, S B , V. '91-2, '07-8 CHURCH, JOHN A, M, '79-8l,'94-6, V, '07-8 COGSWELL, W B, V, '74-5,'86-7

Jan 1, 1910

ALEXANDER, JOHN S, M,'74-6,'81-3 ASHBURNER, C A, M, '85-7 ASMUS, GEORGE, Dl, '78-80 BACON, D H , M, '00-2 BAYLES, JAMES C , M,'80-2,'91-3 P, '84-5, V,'88-9 BIRKINBINE, JOHN, M, '83-5, V, 'S7-J, P, '91-2 BLAIR, THOMAS S , M, '74-43 BLAKE, WILLIAM P , V,'71-4,'76-7,'05-6 BLANDY, JOHN F, V,'71-3,'78-9 BLOW, A A, C, '05-7 BOWIE, A J , JR, V,'93-4 BRAMWELL, J H , A1, '89-91 BROOKS, THOS B , M, '72 BRUNTON, D W , V, 97-8 BUCK, STUART M , M, '83-5 BURDEN, JAMES A, V,'80-1 BURNHAM, WILLIAM, M, '82-4. CAMPBELL, H H, M, '93-5 CHAMBERLAIN, H S , V, '96-7 CHANNING, J PARKE, V,'08 CHRISTY, S B , V. '91-2, '07-8 CHURCH, JOHN A, M, '79-8l,'94-6, V, '07-8 COGSWELL, W B, V, '74-5,'86-7

Jan 1, 1910

J. L. McK. YARDLEY,* Pittsburgh, Pa. (written dlscussion ?) .-It is interesting to observe how closely Mr. Hansen agrees with other investigators to the effect that the art of electrolytic zinc has left the realm of mystery. In his introduction, lie has said practically what Thomas French said in his paper "The Future of Electrolytic Zinc. "1 The successful electrolysis of zinc from sulphate solutions has not been an easy matter, and it is only within recent years that the difficult problem of depositing high-grade zinc has been satisfactorily: accomplished on a commercial basis. The principal requisite is. that the electrolyte shall be quite free from certain impurities. The methods by which freedom from these impurities is assured are now very well understood, and with experienced superintendents there is little difficulty in obtaining a high efficiency in that part of the process. When certain underlying principles are recognized, the difficulty encountered in dealing with the filtration of the acid and slimy solutions also largely disappears, although it has been a very serious one to the uninitiated. In the dissolving of the zinc from the roasted ore, there is nothing which any competent chemical' engineer cannot undertake, and any other operations connected with the electrolytic process are either of little or no difficulty, or are common to the retort process. Mr. Hansen also agrees with R. G. Hall's statement in " Some Economic Factors in the Production of Electrolytic Zinc:"2

Jan 10, 1918

By G. Hileman

At present there are three fields in commercial exploitation in the Argentine. In order of production they are: (1) Comodoro Rivadavia, (2) Salta, (3) Plaza Huincul. Comodoro Rivadavia.—This field is on the coast of the Territory of Chubut in the southern part of the republic. It is being developed and exploited by Yacimientos Petroliferos Fiscales, the government oil entity, and five private companies. The immediate coastal portion of the field, which embraces the original discovery area, is almost completely developed. This is especially true of the original government reserve and one private property. The Y.P.F. has extended its explorations and developments westward to Escalante, 27 km. distant on the state railway. This extension has been the most active and prolific section of the field for the past three years. The government has also continued its exploration drilling in the region lying south of Colonia Sarmiento and east of the Rio Senguer. Private companies have not been able to extend their operations beyond the claims they had in process of acquisition in 1924, when the government reserve areas were established. The Y.P.F. is the major producer of the field and employs modern methods and appliances. Practically all its drilling and pumping operations are electrically operated, from a central power plant. In view of t'he scarcity of water supplies, this facilitates operations and is an economic factor of considerable importance.

Jan 1, 1934

By L. H. de Wald, J. Walter Scott

The removal of lead by fire refining methods from copper of electrolytic quality is growing in importance. Particularly is this true of the refining of secondary copper and copper cathodes obtained from electrolytic cells where lead is used as the anode material, as in the electrolysis of ore-leaching solutions and foul electrolyte. When investigating the removal of small amounts of lead from molten copper in a reverberatory furnace during the refining of secondary copper of otherwise electrolytic copper quality,' it was found necessary first to know something about the distribution of the lead throughout the bath. The authors believe that it is not generally known how small amounts of lead as an impurity are distributed in a molten copper bath; that is, whether the lead is concentrated at the bottom or at the top, or whether it occurs more or less uniformly throughout the bath. The data contained in this report may help, therefore, in the development of a satisfactory fire refining method for the removal of this obstinate element from a molten copper bath. The first step was the development of a method for taking samples from various locations in the bath, at the surface and at various depths. The sampling device used, shown in Fig. 1, consisted of a 10-gram fireclay assay crucible fitted into a ring on the end of a steel rod handle of suitable length. A fireclay scorifier, 2 in. dia., with a ½-in. hole bored in the

Jan 1, 1930

By P. L. Hendricks, J. W. Spretnak

The interstitial atom principally responsible for the yield point and strain aging in electron-beam-melted tantalum is identified by analysis of the kinetics of the return of the yield point after an increment of plastic deformation. Two sets of specimens contained two levels of oxygen with very low hydrogen contents and the third set had comparable oxygen and hydrogen contents. The activation energy for the return of the yield point agrees well with that for diffusion of oxygen for the first two sets of specimens. For the third set of specimens, the activation-energy value lies between those for diffusion of hydrogen and for diffusion of oxygen. The advent of the dislocation model of plastic deformation in metals has revitalized interest in the yield point and strain aging in bcc metals containing a certain minimum content of interstitial solute elements. Much theoretical and experimental work has been performed in recent years to elucidate the detailed mechanism of these phenomena. The purpose of this investigation is to attempt to identify the principal interstitial element responsible for the yield-point phenomenon in electron-beam-melted tantalum by analysis of the kinetics of the return of the yield point after an increment of plastic deformation. Some of the earlier theories of the yield-point phenomenon proposed a grain boundary film of iron carbide. Such models could not satisfactorily explain all features of strain aging and the yield-point phenomena. The most widely accepted explanation is that of Cottrell,1 later extended by Cottrell and Bilby.2 Strain aging is ascribed to "locking" of dislocations by interstitial solute "atmospheres". The yield-point phenomenon results when the dislocations are torn away from their atmospheres. The strain-aged condition is re-established after sufficient time to allow the interstitial atoms to diffuse to the dislocation lines and re-establish the locking atmospheres. Clearly, the Cottrell-Bilby model is concerned with the bulk of the grain and does not specifically involve the grain boundary. The recent modification of the Cottrell-Bilby model is a redirection of attention to the role of the grain boundary and the possibility of multiplication of a limited number of free dislocations rather than unlocking all of the dislocations. Theories have been advanced by Hahn3 and conrad4 which are modifications of the Cottrell-Bilby theory. The model proposed by Hahn indicates that, although the possibility of un- locking anchored dislocations is not excluded, it implies that unlocking is not necessarily required to explain yield drop. Locking of dislocations during the aging treatment is a necessary part of the theory; however, it assumes that dislocations once locked remain locked. It is suggested that the yield drop observed is a result of the following factors: 1) the presence of a small number of mobile dislocations initially, 2) rapid dislocation multiplication, 3) the stress dependence of dislocation velocity. In the case of bcc metals, locking is considered to be the means by which dislocations are immobilized. Cold working of the metal results in the generation of larger numbers of new dislocations and the stress dependence of the dislocation velocity accounts for yield drop observed. Conrad' has proposed a model similar to the one just described which applies to strain aging of iron and steel and which logically could be extended to other bcc metals. This model also does not require large-scale unlocking of dislocations. It is proposed that, during initial loading of a specimen below the upper yield stress, a few dislocations are torn free of their Cottrell atmospheres at regions of stress concentrations. With an increasing stress, some multiplication of dislocations occurs by a double cross slip mechanism, thus giving a preyield microstrain. At some critical stress represented by the upper yield stress, sudden profuse multiplication of dislocations occurs, enabling plastic flow to proceed at a lower stress. In this model, microstrain, preyielding, and flow represent the movement of free dislocations. It should be noted that this model also requires the locking of dislocations by interstitial solute atoms for the occurrence of a yield point; however, unlocking of large numbers of dislocations is not required. If it is assumed that the yield point will return when some fraction of free dislocations produced during pre-straining are pinned, the number of solute atoms required to pin unit length of a dislocation line can be calculated when prestrain and reloading are done at the same temperature and strain rate. Since the migration of solute atoms back to the stress fields of dislocation lines is controlled by the diffusion rate of interstitial solute atoms, it is to be expected that the activation energy for strain aging would be identical to the activation energy for diffusion. It would also be expected that the strain aging observed will be controlled by the fastest diffusing species capable of producing locking over the temperature range investigated. The rate of yield-point return has been found to be adequately expressed by an empirical rate equation of the form: rate=Ae-Q/RT [1] where A = constant, Q = activation energy, R = gas constant, and T = absolute temperature. Cottrell and Bilby2 have expressed the number of atoms per unit length of dislocation line which arrive

Jan 1, 1967

By T. Seldenrath

In the development of a fluid -operated hammer drill' for accelerated penetration of hard rock formations in oil wells, a research investigation was conducted to evaluate the percussion effects obtained with different design characteristics and to determine the possibilities of percussion in the low frequency range. Tests were conducted on granite blocks and comparable impact forces were measured with a load cell under selected test conditions. These full-scale laboratory tests provided an evaluation of the effectiveness of percussion which was further supported by actual downhole field performance. While much pertinent data have been presented by other investigators the method of evaluation described in this article resulted in good correlation between laboratory and field performance and may be applicable in other low frequency percussion developments. EXPERIMENTAL METHOD For these tests the bit was held stationary and the test block was rotated and forced upward against the bit by a hydraulically-lifted rotary table. "Weight on bit" was calculated from pressure readings on the fluid system of the lifting cylinders—corrected for tare and friction. Percussion was obtained with several tubular hammers of different weights up to 320 lb. These were lifted mechanically and allowed to drop by gravity from various heights onto a slidably-mounted bit sub or "floating anvil" for calibration of the load cell response with known kinetic energy of the hammers. During evaluation of percussion effects, the hammers were hydraulically operated to provide a range of percussion frequencies up to 1,020 blows per minute delivered to the anvil. To obtain comparable test readings, the load cell of the strain gauge type, was attached to the bottom of the anvil or bit sub in place of the bit. The load cell rested on a typical granite test block mounted on the drilling table. The latter was hydraulically supported as in the actual drilling operation. The effect of support resistance was the same for all tools when calibrating. Impact forces so determined werethusdirectly comparable with one another for the purposes of this investigation. When a roller bit was substituted for the load cell for actual drilling, the impact force would probably be reduced due to the resiliency of the bit body, legs. cones and teeth and the penetration of the teeth into the rock. However, since the bits and rock specimens were uniform in these tests, an evaluation of actual tool performance, in terms of parameters previously determined with the load cell at the selected standard conditions of calibration, proved satisfactory. Throughout these tests, 8¾-in. standard tricone, hard rock toothed roller bits and carbide-insert roller bits were used. Rotary speeds were 50 and 100 rpm; static weight on bit was applied up to 40,000 Ib, and percussion frequencies up to 1,020 blows per minute were available. During this investigation it was found that toothed bits on which the teeth had developed flat ends about 3/16 in. wide did not change appreciably for the duration of a test. Hence, all toothed bits used in this study were in this condition. Conventional reference curves obtained in these tests show that increasing weight on hit by 2:1 yielded an increased penetration rate of approximately 2.7:1, while an increase in rotary speed of 2:1 netted an increased penetration rate of roughly 1.7:l. Results are thus of the same order as those reported for hard rock drilling by other investigators." CALIBRATION Under the selected standard test conditions previously described, with the lifting table hydraulically supported, and the anvil interposed between hammer and load cell, the hammers were dropped from known heights. Thus, with the kinetic energy of the hammer known, the corresponding maximum impact force shown by the cell was determined. (It may be of passing interest to note here that special drop tests with the hammers showed that no appreciable reduction in impact force resulted from introduction of the anvil or hit sub.) From these calibrations, it was possible to determine the theoretical kinetic energy available in the hammer from the maximum impact force shown by the load cell while operat-

By A. H. Geisler, J. H. Keeler

Preferred orientations in rolled and annealed titanium sheets were determined by the Geiger counter spectrometer X-ray diffraction technique. Five annealing textures dependent upon the temperature range of annealing were found, and in order of increasing annealing temperature pendent upon the temperature range are: 1—a deformation like texture, 2—a rotated inorder a-recrystallization temperature texture, 3-a retained u-recrysraIlization texture, on annealing at lower temperatures of the ß-region, 4—a transformation texture based on recrystallized a and predicted by the Burgers' relationship, and 5—a ,ß-cube texture. These results are examined in terms of current theories of recrystallization textures. UMEROUS investigators have described the tex- ture obtained by cold rolling the hexagonal metals, titanium, zirconium, and beryllium, which have c/a ratios less than that of ideal packing, 1.633. The basal planes are rotated out of the rolling plane, about the rolling direction, so that the basal poles are tilted toward the transverse direction as shown schematically in Fig. la. In all instances but one,' it was also reported that the [1010] direction was parallel to the rolling direction (see Fig. lb). Hot rolling has been reported as causing a similar tilt of the basal poles in the transverse direction (see Fig. la) and causing the [1010] direction also to be parallel to the rolling direction as shown schematically in Fig. lb. Annealing after deformation does not appreciably change the tilt of the basal poles in the transverse direction." Beryllium2-7 continues to have the [1010] direction in the rolling direction after annealing, and similar observations for titanium and zirconium' . have been reported for annealing at fairly low temperatures, again as in Fig. lb. At higher annealing temperatures, however, the recrystallized grains of titanium" and zirconium have an orientation such that the [1120] direction is approximately in the rolling direction, although the basal poles are still inclined in the transverse direction. Figs. la and lc show the resulting orientations schematically. This change in orientation has been described as a nominally ±30° rotation of the hexagonal crystallites about the basal poles of the cold rolled texture and is apparent from the results which are summarized in Table I for investigations with the X-ray diffraction technique employing film. The angles y, , and ß are indicated in Fig. 2 which represents the stereographic projection of (1070) poles for the mean orientation of a pole figure. Texture determinations for titanium using the Geiger counter spectrometer have provided similar results except that in some instances additional components of the texture were proposed, as shown by the summary of data in the upper half of Table 11. On the other hand, the spectrometer technique, when applied to zirconium,* has revealed a splitting Recently completed studies of the textures of annealed zirconium", show zirconium to possess textures very similar to those reported here for titanium. Therefore, much of this discussion will include zirconium by virtue of its close similarity to titanium in pref erred orientations. of the intense areas of the pole figure for samples annealed at 600°C. This splitting could be described by a 7" rotation of the tilt axis about the normal to the rolling plane. Such a splitting for the annealed texture relative to the cold rolled texture was not observed in other determinations for either zirconium or titanium using the less sensitive film X-ray methoe and makes the relationship between the two types of texture more complex than the simple rotation about the (0001) pole based on film work. The more precise investigations on zirconium permit the descriptions in the lower part of Table 11, which show that the texture depends quantitatively on the temperature of annealing. When zirconium is annealed at temperatures up to 400°C, the texture is similar to the cold rolled texture, while annealing in the range 500" to 900°C produces a texture which is only approximately described as [11%] in the rolling direction. More precisely described results for zirconium show that the two types of splitting ( 1—about an axis in the rolling plane through an angle given in the second column in Table II and 2—about the normal to the rolling plane through an angle given in the third column of Table 11) depend on annealing temperature. The [1120 is the rolling direction only when the annealing temperature is in the vicinity of 900°C

Jan 1, 1957

By A. E. Blakeslee

Morphological and electrical properties of GaAs epitaxial layers are influenced not only by changes in the nominal substrate orientation but also by small amounts of misorientation from the exact crystal planes. Deviations up to 5 deg from {11IA}, {11IB}, and (100) planes were investigated. Growth rates increase progressively with angle, approximately I u per hr per deg. Size and density of growth pyramids fall off with increasing angle, but other effects that are deleterious to the surface may occur which are heightened by increased misorientation. Carrier concentration decreases and electron mobility consequently increases as the angular offset increases, except in the case of strong compensation, where the mobility trend is reversed. It has long been known that changes in the crystallo-graphic orientation of the substrate may cause pronounced effects on the morphological properties of vapor grown semiconductor films. Reports of orienta-tion-dependent growth rates and surface characteristics are as old as the literature on epitaxy itself. shawl has recently published a comprehensive study of the dependence of growth rate on substrate temperature and orientation in epitaxial GaAs. It is also well-known that misorienting the substrate surface a few degrees away from the nominal low-index crystal-lographic plane often produces a much smoother epitaxial surface. This was reported by Tung2 for silicon, Reisman and Berkenblit3 for germanium, and by Kontrimas and Blakeslee4 for GaAs, and use is commonly made of this fact in the semiconductor industry to help guarantee smooth vapor deposits. The effects of substrate orientation on the carrier concentration and mobility of vapor grown GaAs were first documented by williams5 in 1964 and have been observed by several other authors since then,6,7 but no one has yet reported a careful study of how small changes influence these properties. We have made such a study and have found that sizable differences in growth rate, morphology, carrier concentration, and mobility can indeed be observed for epitaxial films grown on substrates that are oriented by progressive small increments away from the exact crystal plane. EXPERIMENTAL Early in the investigation an arsine synthesis system of conventional design8 was employed to produce growths on {111A}-oriented GaAs substrate crystals. In that early work, pronounced effects on carrier concentration and electron mobility were observed as a function of slight misorientation from this low index plane. That observation led to the more careful study that is reported here. An AsC13 system, differing in major aspect from those commonly in use today9 only in that the reactor is vertical rather than horizontal, was used for the detailed study. The gallium source was at 900°C and the substrates were at 750°C. The flow rate of pal-ladium-diffused H2 through the AsCl3 bubbler was 200 cu cm per min, and the flow rate of bypass H2 was also 200 cu cm per min. The substrates consisted of chro-mium-doped semiinsulating GaAs to facilitate elec-trical evaluation of the overgrowth by means of Hall and conductivity measurements on conventional eight-legged Hall bridges. They were misoriented by 0 to 5 deg from the {111A}, {111B}, and (100) planes, toward the (100) from the {111A} and {111B} and randomly toward the <111A> or <111B> from the {loo). The crystals were oriented for sawing by the Laue back-re-flection technique, which is good only to about ±1/2 deg; but after polishing or sometimes after epitaxial growth the wafers were checked by a diffractometer technique which is accurate to about * 0.1 deg. After lapping, the wafers were polished with NaOCl after the technique of Reisman and Rohr,10 and just before use they were cleaned in NaOC1, thoroughly rinsed with de-ionized water, and blown dry with nitrogen. Each run employed four wafers, each misoriented by differing amounts from one of the three major faces, and at least two runs were made for each orientation. The runs were continued long enough to provide at least a 15-µ or thicker layer. SURFACE MORPHOLOGY The appearance of all the films that were grown in a given run always changed from wafer to wafer as a function of increasing misorientation, but not always in the same regular fashion. At least three different trends were observed. These are more easily seen than described, and reference to the series of photo-

Jan 1, 1970

By Allan E. Martin, Harold M. Feder, Irving Johnson

The cadmium-uranium system was studied by thermal, metallographic, X-7-ay and sampling techniques; special emphasis was placed on the establishment of the liquidus lines, The single inter metallic phase, identified as the compound UCd11 melts peritectically at 473°C to form a-umnium and melt containing 2.5 wt pct uranium. The cadmium-rich eutectic (0.07 wt pct uranium) freezes at 320.6°C. Solid solubilities in uraizium and cadmium appear to be negligible. Between 473°C and 600°C the liquidus line is retograde. NO publication relating to the cadmium-uranium phase diagram was found in the literature. The establishment of this diagram was of considerable interest to us because of a possible application of the system to the pyrometallurgical reprocessing of nuclear fuels. Analysis of liquid samples, metallographic examination, thermal analysis, and X-ray diffraction analysis were used to establish the phase diagram from about 300° to 670°C. Particular emphasis was placed on the establishment of the liquidus lines. The same system was concurrently studied in this laboratory by the galvanic cell method.&apos; Both studies benefited from a continual interchange of information. MATERIALS AND EXPERIMENTAL PROCEDURES Stick cadmium (99.95 pct Cd, American Smelting and Refining Co.) contained 140 ppm lead as the major impurity. Reactor grade uranium (99.9 pct U, National Lead Co.) was most often used in the form of 20-meshspheres. This form was particularly suitable because it does not oxidize as readily as finer powder. The liquidus lines were determined by chemical analysis of filtered samples of the saturated melts. The liquid sampling technique is described elsewhere2 alumina crucibles (Morganite Triangle RR), tantalum stirring rods, tantalum thermocouple protecthecadmiumtion tubes, Vycor or Pyrex sampling tubes, and grades 60 or 80 porous graphite filters were used. Uranium dissolves in liquid cadmium rather slowly. In order to achieve saturation of the melts it was necessary to modify the procedure of Ref. 2 by the use of more vigorous stirring and longer holding periods (at least 3 hr) at each sampling temperature. The samples were analyzed for uranium by spectro-photometry (dibenzoyl methane method) or by polar- ography. The analyses are estimated to be accurate to 2 pct. Thermal analysis was performed on alloys contained in Morganite alumina crucibles in helium atmospheres. Standard techniques were employed; heating and cooling rates were about 1°C per min. For the determination of the peritectic temperature, Cd-10 pct U charges were first held for at least 50 hr at temperatures in the range 435° to 460°C to form substantial amounts of the intermediate phase. For the determination of the effect of cadmium on the a-p transformation temperature of uranium, charges of Cd-25 pct U (-140+100 mesh uranium spheres) were first held near the transformation temperature, with stirring, to promote solution of cadmium in the solid uranium. The holding times and temperatures for these treatments were 18 hr at 680°C for the cooling run and 28 hr at 630°C for the heating run. Alloy specimens for X-ray diffraction and metallographic examination of the intermediate phase were prepared in sealed, helium-filled Vycor or Pyrex tubes. Ingots from solubility runs and thermal analysis experiments also were examined metallographically. Crystals of the intermediate phase were recovered from certain cadmium-rich alloys by selective dissolution of the matrix in 20 pct ammonium nitrate solution at room temperature. Temperatures were measured with calibrated Pt/Pt-10 pct Rh thermocouples to an estimated accuracy of 0.3°C. However, the depression of the freezing point of cadmium at the eutectic is estimated to be accurate to 0.05°C because a special calibration of the thermocouple was made in place in the equipment with pure cadmium just prior to the measurement. EXPERIMENTAL RESULTS The results of this study were used to construct the cadmium-uranium phase diagram shown in Fig. 1. This diagram is relatively simple; it is characterized by a single intermediate phase, 6 (UCd11), which decomposes peritectically, and which forms a eutectic system with cadmium. The solid solubilities in the terminal phases appear to be negligible. An unusual feature of the diagram is the retrograde slope of the liquidus line above the peritectic temperature. The Liquidus Lines. The liquidus lines above and below the peritectic temperature are based on three separate solubility experiments. The data are shown in Fig. 1 and are given in Table I. It is apparent from the figure that the solubility data obtained by the approach to saturation from higher temperatures fall on substantially the same lines as those obtained

Jan 1, 1962

By A. Szirmae, Hsun Hu

The early stages of recrystallization in a 70 pct cold-rolled Si-Fe crystal of the (110) (0011) orientation were studied with a Siemens electron microscope. Orientation studies based on electron-diffractzotz. patterns confirm the results of previous texture analysis. The driving energy for recrystallizatior and the critical radius for growth were calculated from the dislocation energy and the energy of the subgrain bourzdaries, and it was found consistent with the observed size of the recrystallized grains. The recrystallization characteristics of crystals with different initial orientations are discussed. The recrystallization of cold-rolled (110)[001] crystals of Si-Fe has been widely studied by various investigators.1-4 Their results on both deformation and annealing textures are in good agreement. The rolling texture after 70 pct reduction consists mainly of two crystallographically equivalent (111) [112] type textures and a minor component of the (100) [011] type. The latter is derived from the deformation twins, or Neumann bands, which are formed during the early stages of deformation and later rotate to the (100) [011] orientation upon further rolling reduction. Between the two main (111) [112] type textures, there is some orientation spread, because of which very low intensity areas appear in the pole figure. If these very low intensity areas are considered to be a very weak component in the texture, then a (110) [ 001 ] orientation may be assigned to them. When this rolled crystal is annealed at a sufficiently high temperature for recrystallization, the texture returns to a simple (110) [001]. The purpose of the present investigation was primarily to seek a better understanding of the recrystallization process by using the electron transmission technique. The (110) [0011 type of crystal was selected because orientation data for it are well known from previous studies with conventional techniques. Direct observations on the recrystallization of such a crystal have also been made by using a hot-stage inside the electron microscope, and the results will be reported in another paper. MATERIAL AND METHOD A single-crystal strip of the (110) [001] orientation was prepared from a commercial grade 3 pct Si-Fe alloy by the strain-anneal technique.= The strip was approximately 0.014 in. thick, and was rolled 70 pct at room temperature to a thickness of 0.004 in. Specimens were cut from the rolled strip and were annealed in a purified hydrogen or argon atmosphere. They were then electrolytically polished in a chromic-acetic acid solution to very thin foils. Best results were found by polishing first between two narrowly spaced flat cathodes with the specimen edges coated with acid-resisting paint, followed by polishing between two pointed electrodes until a hole appeared in the center as described by Bollmann.6 It was found that a thin transparent film always formed along the thin edges of the polished specimen. This film was then removed by rinsing the specimen very briefly in a solution of alcohol with a few drops of HF or HCl. RESULTS AND DISCUSSION 1) The Deformed Crystal. From the electron-diffraction patterns taken at various areas of an as-rolled specimen, the texture components as deduced - from ordinary pole-figure analysis were confirmed. Over most of the areas where orientation was examined, a (111) pattern with a [112] direction parallel to the rolling direction was obtained. This corresponds to the main deformation texture of the (111) [112] type. In a few areas the diffraction pattern was (100) [Oil], corresponding to the minor-texture component derived from the Neumann bands. The (110) [001] orientation, which corresponds to the very weak intensity area in the pole figure, was found infrequently. A typical example of the deformed matrix having the (111) type main texture is shown in Fig. 1, where (a) is the microstructure and (b) is the diffraction pattern taken from that area. It was also frequently observed that in other areas more or less continuous rings of weaker intensity were superimposed on the simple (111) diffraction pattern, suggesting the presence of a wide range of additional orientations. Other evidence indicated that the recrystallization characteristics are different in these two different types of areas. The hot-stage observations which provide this evidence will be discussed in another paper. AS shown in Fig. l(a), numerous dislocation-free areas of very small size are embedded in the "clouds" of high-dislocation density. This indicates that the deformation of a single crystal, even after a rolling reduction of 70 pct, is far from uniform on a micro-

Jan 1, 1962

By Charles L. Mantell, George Ferment

This investigation determined the jeasibility of current-potential curves as an analytical tool for monitoving manganese electroicinning solutions for metallic impurities. Nine metallic impurities were studied: trickel, cobalt, silver, copper, zinc, molybdenum, catlmiun magnesium, and sodium. The individual effect of each metallic irzplrl,iLy on the standard point-izatiorr was determined for a range of &apos;concentration. Not all of Ihe impurities affected the polarization curve; correlation between transition current and cotrcetztration of impurity. Molybdenum had an uncorrelated effect on the polarization curie. The effects of binary mixtures of impurities were studied to see if the transition current of the mixture could be predicted. Interactions occurred between impurities which prei&apos;etzted the pvecliction the transition current of tile rrlisLitr.e by additive laws. The polarization curve was shown to be sensitive to metallic impurities which affect the current efficiency of a manganese cell. THE application of current-potential curves in manganese electrowinning is not new but played an important part in the conversion of an inoperative large-scale pilot plant into a continuous comnercial operation.1"" The effects of trace metallic impurities in manganese electrowinning solutions on cathode current-potential curves,5-19 specifically nine impurities (nickel, cobalt, silver, copper, zinc, molybdenum, cadmium, magnesium, and sodium) were studied for a range of concentrations. Cadmium, magnesium, and sodium had no effect. Nickel, cobalt, silver, copper, and zinc yielded a correlation between transition current and concentration of impurity: molybdenum had an uncorrelated effect. Binary mixtures of impurities were studied to de-termine if the transition current could be predicted from the values for the individual constituents. Interactions between impurities prevented the prediction of the transition current of the mixtures by an additive law. The polarization curve was shown to be sensitive to metallic impurities which affected the rurrent efficiency of a manganese cell. The electrowinning of manganese relies upon maintaining a high-purity electrolyte. Purification schemes were developed to remove all of the heavy metals, the magnesium and calcium. Concentration limits have been established for single impurities. With high-purity electrolytes, favorable cell efficiencies are consistently obtained; but with impure solutions there is a reduction in efficiency. With the rapid rise to commercial prominence of electrochemical processes, there has been a lag in developing rapid methods for determining whether an electrolyte is sufficiently pure for efficient electrolysis. The most sensitive test for impurities is the behavior of the electrochemical cell. Impure electrolytes will cause a serious reduction in cell efficiency, and in many cases metal deposition will be prevented or reversed. The effects of impurities are not usually evident until after long periods of electrolysis, resulting in a disruption of the process. A method which could predict the behavior of an electrolyte in terms of cell efficiency prior to reaching the commercial cell is needed. Van Arsdale and Maier," Allmand and Campbell,a1&apos;22 and others attempted to develop an electrochemical process for manganese,"3"29 but all met with some degree of difficulty. Jacobs et a studied the effects of metallic impurities in manganese electrowinning. Plant methods were based on a 2-hr plating in a small electrolytic cell. The final method was based on a 24-hr plating run, performed in a relatively large test cell. Here, current efficiencies were calculated with and without impurities in the electrolyte, and the critical concentration was established as the maximum amount of impurity that the electrolyte could tolerate before there was a serious loss in efficiency. The amount of impurity that could be tolerated decreased as the plating time increased, indicating deposition of the impurity. This test duplicated the conditions of commercial practire, and was sensitive to impurities. Small amounts of impurities significantly affect the hydrogen overvoltage at a metal surface, increasing or decreasing it depending upon the nature of the impurity. ockris established the limit for the onset of poisoning at 10-l moles per liter. The effects of impurities were studied by potential-time curves at a constant current density. The technique did not lend itself to rapid analysis in that several hours were needed to establish stable potential-time curves. Serfass and coworkers3&apos; developed calorimetric and spectrophotometric techniques for analyzing for trace impurities. Our method4&apos;" is based on current-cathode potential curves produced by continuously changing the cell voltage at a programmed rate. Starting with a clean stainless-steel cathode, the cell voltage was initially adjusted to yield zero current: the program was then started and the current was plotted as a function of the cathode potential. Fig. 1 is a typical current-potential curve. In initial region A the hydrogen-evolution reaction predominates and the polarization curve

Jan 1, 1967

By O. C. Baptist

The Umiat oil field is in Naval Petroleum Reserve No. 4 between the Brooks Range and Arctic Ocean in far-northern Alaska. The Umiat anticline has been tested by 11 wells, six of which produced oil ; however, [lie productive capacity and recoverable reserves of the field are subject to considerable speculation because of unusual reservoir conditions and because several wells appear to have been .seriously damaged during drilling and completion. Oil is produced at depths of 275 to 1,100 ft; the depth to the bottom of the permanently frozen zone varies from about 800 to 1,100 ft, .so that most of the oil reserves are in the permafrost Reservoir pressures are estimated to range from 50 to 350 psi, increasing with depth, and the small amount of gas dissolved in the oil is the major source of energy for production. Laboratory tests were made on cores under simulated permafrost conditions to estimate oil recoverable by solution-gas expansion from low saturation pressures. The cores were also tested for clay content and susceptibility to productivity impaiment by swelling clays and increased water. content if exposed to fresh water. The results indicate that oil can be produced fronz reservoir rocks in the permafrost and that substantial amounts of oil can be produced from depletion-drive reservoirs by a pre.s.r~lrr drop of as little as 100 psi below the saturation pressure. Freezing of formation water reduces oil productivity much more than that due to increased oil viscosity: Failure of we1ls drilled with rtuter-base mud to produce is attributed to freezing of water in the urea immediately surrounding the wellbore. Swelling clays apparently contributed very little to the plugging of the wells. INTRODUCTION Naval Petroleum Reserve No. 4 lies between the Brooks Range and the Arctic Ocean in northern Alaska. The Umiat oil field is located in the southeastern part of the Reserve and is about 180 miles southeast of Point Barrow (the only permanent settlement in the Reserve and the primary supply point for drilling of the wells at Umiat). Eleven wells were drilled for the U. S. Department of the Navy, Office of Naval Petroleum and Oil Shale Reserves, between 1944 and 1953 to test the oil and gas possibilities of the Umiat anticline. Six of these wells produced oil in varying quantities and the best one pumped about 400 B/D.&apos; Estimates of recoverable oil range from 30 to 100 million bbl. The main oil-producing zones are two marine sandstone beds in the Grandstand formation of Cretaceous age: these are referred to as the upper and lower sands. Good oil shows were found throughout the sand settions in the first three wells drilled on the structure, but the highest rate of oil production obtained on any 01 the many tests was about 24 BOPD. These first wells were drilled with conventional rotary methods using water-base mud; later wells were drilled either with cablc tools using brine or rotary tools using oil or oil-base mud. These experiments were successful as is shown by comparing the oil production from Well No. 2 with that from No. 5. These two wells are only 200 ft apart and are located at about the same elevation on the structure. Well No. 2. drilled with a rotary rig using water-base mud, was abandoned as a dry hole after all formation tests were negative. Well No. 5. drilled with cable tools and reamed with a rotary using oil, pumped 400 BOPD which was the maximum capacity of the pump and less than the capacity of the well. These field results indicated that the producing sands were extremely "water sensitive" and it was assumed that the cause of this sensitivity was the presence of swelling clays in the sands. Because of the very unusual reservoir conditions and the difficulties encountered in completing oil wells in the permafrost. the Navy asked the U. S. Bureau of Mines to make laboratory studies under simulated permafrost conditions to assist them in estimating the production potential of the field and the recoverable reserves. These tests were designed to determine the cause of the plugging of wells in the permafrost and to test oil recovery from frozen sand by solution-gas expansion with the oil gas-saturated at very low pressures. EXPERIMENTAL METHODS AND PROCEDURES Samples Analyzed Core samples were analyzed that represent the lower sand in Umiat Well No. 7, the upper sand in No. 3. and both the upper and lower sands in No. 9. These sands should be productive in all of the wells because of their location on the structure. Core samples from

By R. V. Mrazek, F. E. Block, S. B. Knapp

The mixed homogeneous and heterogeneous kinetics of the thermal decomposition of tungsten hexacarbonyl were studied by employing a batch reactor. The system was such that a sample of tungsten hexacarbonyl could be injected into the preheated reactor, and the progress of the reaction followed by a simple pressure measurement. Both the homogeneous and heterogeneous reactions were found to be first order, and approximate activation energies were determined for each reaction. It is shown that the dis-proportionation of carbon monoxide to give carbon and carbon dioxide cannot be the source of carbon in tungsten deposits prepared by this reaction. The kinetics of the thermal decomposition of tungsten hexacarbonyl have been investigated as part of a continuing study by the U.S. Bureau of Mines on the decomposition of organometallic compounds. Reactions involving the thermal decomposition of metal carbonyls have a potential application in the preparation of pure metals and fine metal powders. Indeed, it was these applications which provided the impetus for much of the early work involving the carbonyls of nickel1 and iron.&apos; The relative lack of study of other metal carbonyls can be traced to the comparative difficulty in synthesizing these compounds. The most common use for tungsten hexacarbonyl has been as an intermediate in vapor-phase plating.7&apos;8 However, attempts to obtain a carbon-free deposit of tungsten by this method have not been successful, and some investigators have taken advantage of the carbon contamination and used this process to form tungsten carbide deposits.lo Other investigators have studied the thermodynamic properties11"14 and molecular structure of tungsten hexacarbonyl. However, very little is known about the kinetics of this thermal decomposition, the mechanisms involved," or the source of carbon in the resulting plate. In contrast, studies have been made of the kinetics of the thermal decomposition of nickel tetracarbonyl, iron pentacarbonyl, and molybdenum hexacarbonyl.&apos;l It has been found that these thermal decompositions occur by a mechanism which is partially heterogeneous in nature. Information available on the equilibrium constants for the decomposition of tungsten hexacarbonyl was used to determine a temperature range, 500" to 560°K, in which the reaction could be expected to be essentially complete. APPARATUS The apparatus used allowed the injection of a sample of tungsten hexacarbonyl into a preheated batch reactor and the use of a simple pressure measurement to follow the progress of the reaction in the sealed reactor. The pressure was sensed by means of a pressure transducer (Consolidated Electrodynamics Corp., 0.3 pct)* capable of operating at the *Reference to specific products is made to facilitate understanding and does not imply endorsement of such brands by the Bureau of Mines._______ reaction temperature. This type of sensing element was chosen to avoid the problem of condensation of the sublimed carbonyl in the capillary tubing leading to any type of remote pressure-sensing device. stirring was provided by rotating the entire apparatus. Glass beads placed in the reactor provided a pulsating agitation. To minimize thermal gradients in the reactor walls, the reactor was constructed of aluminum. The support tube which held the reactor in the furnace was thin-walled stainless steel to minimize heat conduction out of the reactor. As a result of these measures, a nearly uniform temperature (°C) was maintained throughout the reactor. Fig. 1 is a schematic diagram of the apparatus. The small gear motor rotated the entire apparatus at about 200 rpm. The bearings shown at the ends of the air cylinder were perforated to allow air to be fed to the charging piston and to allow inert gas to be fed to the reactor during the preheating period. The sample was simultaneously injected and sealed inside the reactor by operation of the air piston. Fig. 2 shows a cross section of the air cylinder and the adjoining portion of the support tube leading to the reactor. The sample carrier is shown in place at the right-hand end of the injection rod extending from the air piston. The piston is shown in the retracted position, as it would be prior to the start of an experiment. The small Teflon gasket which encircled the sample carrier at the end of the injection rod sealed the reactor when the sample was injected. This seal was maintained throughout the test by maintaining air pressure on the piston. The sample carrier was a 2-in. section of thin-walled, -in.-diam nickel tubing with an internal blank about 1 in. from the base and with the base end sealed.

Jan 1, 1969

By Chas. A. R. Lambly

In the extreme northeast corner of the State of Washington, on the Canadian border, lies the Metaline mining district. This district is old in history, but young in production. Geology The Metaline district is a zinc-lead area of the replacement type in dolomite and limestone. The ore bodies of the Josephine horizon are in many ways similar to the ore bodies of the famous Tri-State zinc fields. The beds are faulted and folded and have varying low dips in varying directions, and underlie large areas of the district. History Production started in 1927 on a very limited basis. The property is now mining and milling 700 tons per day. The mine is opened by adit tunnels and a vertical shaft. As the ore horizons gained depth, it was necessary to sink inclines to follow the ore horizon (see Fig 1). From 1927 to date, approximately 600,000 ft of diamond drill was put down This work indicated that suficient tonnage existed to justify a redesigning of the whole operation, surface and underground. After four years of general study, the following program was planned: 1. A new mine entrance, which would be an incline, that could follow the ore body down at whatever pitch was necessary. The incline will be equipped with conveyors for the moving of ore and waste to the surface and with tractor-type locomotives for man and supply transportation. 2. The new incline also required a new type of mining which was developed and is now in use. It is called contour mining and will be described in a future paper. 3. The new incline exit would necessitate the moving of the mill and mine shops across the Pend Oreille River. This part of the program is now underway. The Incline The sinking of the incline was to start as soon as World War II ended and was as follows: The first leg of the incline was to be sunk from the surface 1600 ft on a 17" slope. The collar and first level at elevation 2180 ft, the second level at elevation 2000 ft, the third level at elevation 1875 ft, and the fourth level at elevation 1700 feet. From the 1700 ft elevation the incline was to flatten out to 12" for 400 ft to give the necessary depth for the ore pockets below the 1700 ft level and the necessary clearance for future sinking (see Fig 1 and 2). Due to lack of manpower in 1946, the program was changed and was as follows: A drift was driven from the old mine workings on the 1700 ft elevation in an easterly direction. At 1300 ft the drift was turned N 50" E and at this point a raise was driven 180 ft on a 50" slope. This raise intersected the Josephine horizon and commercial ore was encountered. At the 2000 ft mark, a main raise was driven, 245 ft on a 50" slope, and the 1875 ft elevation was cut. Exploration drifts were started on this level and production followed on a limited basis. The main drift at the 2500 ft point was turned N 35" E and ran parallel to and 10 ft east of and under the proposed incline line. At the proposed intersection of the drift and incline on the 1700 ft elevation, it was planned to raise the incline to intersect the 245 ft raise and to continue on to the surface, a distance of 1600 ft. When this proposed intersection point was reached, a heavy flow of water, approximately 800 gpm, was encountered and all work on the main drift face was stopped. This water flow flooded the main pump station in the old mine and the two lower levels with approximately 20,000,000 gal of water. The water was controlled and finally drained from the cave areas and lower levels after six months of pumping. After the heavy flow of water was encountered in the main heading, it was decided that the incline would have to be started from the surface, as originally planned, so that too much time would not be lost. The surface overburden had to be removed, a total of 6000 yards. A temporary dry house for 6 men was built. An 8 in. churn drill hole was intersected in the first raise driven from the 1700 foot elevation tunnel. Air and water lines were placed in this hole, and air and water were delivered to the collar of the incline from the mine working. The incline started down at 15 ft wide and 7 ft high through the Leadbetter slates. After sinking 4 sets, it was

Jan 1, 1950

By Lars Thomassen, Ernest Kirkendall, Clair Upthegrove

THE amount of research done in the last few years on the subject of diffusion in solid metals is significant of the importance of this problem. To review the literature dealing with diffusion is unnecessary here. Desch1 in 1912 reviewed the work that had been done on diffusion in solids and gave a bibliography of the literature published before that time. Mehl&apos;s paper in 19362 is an excellent review of diffusion in metals and contains a large bibliography. Of importance also for its review and bibliography is an article by A. I. Krynitsky.3 While considerable material has appeared in the literature on diffusion in brass, the amount of information is not great compared to that pertaining to some of the other alloys. Most of the information published is of a qualitative nature; that which is quantitative varies considerably. Thus the quantitative determination of the rates of diffusion of copper and zinc in alpha brass by a new method appeared worth while. In the present investigation the rate of diffusion of zinc in approximately the same composition alpha brass has been determined at three temperatures. PROCEDURE The method used consisted of plating copper on a beta brass, heating it to allow diffusion to take place, and measuring the concentration of copper by determining the lattice constant of the alloy. This method is unique in that it uses a beta brass of such a composition that at the temperature at which diffusion takes place the beta brass is saturated with copper. Thus, while the beta brass supplies the zinc, no diffusion takes

Jan 1, 1938