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By Franz Wever

The importance of the Widmanstätten structure to structure theory in metallography has been recognized by many writers.l It is a structure produced by the precipitation of a, new phase from a solid solution upon cooling as a result of changing solid solubility, and displays a characteristic appearance indicating a crystallographic relationship between the new phase and the original solid solution (Fig. 1). First discovered in 1808 by Alois de Widmanstätten2, the structure has been traced by analogy through many alloy systems. Particularly is this true of the steels. Sorby's classic work3 on the microstructure of iron and steel was in essence an attempt to explain the origin of this characteristic structure in meteoric iron. He observed in a Ressemer steel and in a cast-steel ingot structures which we now recognize as typical Widmanstatten figures.4 Osmond Observed structures in a steel ingot analog-ous to those found in meteorites. Arnold and Mc William6 obtained (and recognized) a

Jan 1, 1931

By H. G. Warren, E. W. Hough

Correlation of interfacial tension of the methane-n-pentane and methane-n-decane systems was made by Hough and Stegemeier by the use of the Weinaug and Katz equation. The methane-n-heptane and ethylene-n-heptane systems were investigated by the authors. Additional systems taken from the literature were the me thane-propane system by Weinaug. and Katz, the methane-n-butane system by Pennington and Hough, and the n- butane -carbon dioxide system by Brauer and Hough. These systems were analyzed by the Weinaug-Katz equation and the Sugden equation on the IBM 1620 11 computer using a regression analysis program. Parachor and exponent values for each component and system were determined. The experimental work was close to the critical point of the light component in the n-butane-carbon dioxide and ethylene-n-heptane systems, between the critical points of the light and heavy components in the methane-n-pentane, methane-n-heptane and methane-n-decane systems, and close to the critical point of the heavy component in the methane-pmpane and methane-n-butane systems. An empirical formula was developed to find a value of the constant B in the Sugden equation for binary hydrocarbon systems from the parachor values of the two components. Interfacial tension for binary hydrocarbon systems was found to be a direct function of liquid-vapor phase density difference in the same manner as a single-component system. DISCUSSION Interfacial tension may be defined as the measure of the specific free surface energy between two phases having different compositions.1 The interfacial tension (IFT) for a binary system may be predicted for any temperature and pressure if the

Jan 1, 1967

By A. P. Young, F. C. Holden

IN many of the early investigations of the aging of titanium alloys, it was observed that the retained beta phase could be aged to a high hardness without an apparent change in microstructure; moreover, in some alloys it was found that even a very rapid quench produced beta having an anomalously high hardness. What appeared to be hard beta phase was designated as "beta prime," to distinguish it from the softer normal retained beta phase. Frost and co-workers'.' demonstrated that the increased hardness is caused by the formation of a metastable phase, omega, which can be identified from its X-ray diffraction pattern. This reaction also has been studied by Brotzen, et a1.,3 and the structure of the omega phase has been published by Silcock, et al.," and by Austin and Doig.3 The X-ray diffraction analysis by Austin and Doig indicated that omega is low in alloy content, approaching the composition of the stable alpha. The aging process proceeds by the path Thus, overaging results in the formation of alpha and the ultimate disappearance of omega. This is accompanied by a decrease in hardness and a recovery of ductility. The present work represents a study of the aging process in a high-purity Ti-6.4 Mn alloy, in which optical and electron microscopy, X-ray diffraction, and hardness data were correlated. The specimens, 1/8-in. sections cut from 1/4-in.-diam rod, were heated in argon to a temperature just into the beta field (810°C), held for 1 hr, and water-quenched. The aging samples were heated in air for 1 hr at 300 to 500°C. The specimens were ground and mechanically polished, finishing with alternate etching and polishing on a slow-speed wheel to remove disturbed metal from the surface. The surface finally was swab-etched, rinsed with tap water, and air-dried. The etchant used was an aqueous solution containing 1 1/2 pct HF and 3 1/2 pct HNO3. This procedure is identical with that used for preparing metallographic specimens, except that the optimum degree of final etching required for electron microscopy may vary from that used for light microscopy. Metal replicas, backed with silica, were prepared from plastic strip-pings for examination with the electron microscope. Complete details of the procedures used for preparing these replicas are available elsewhere." Fig. 1 shows a comparison between the structures revealed by the electron microscope and those obtained by conventional light microscopy. Hardness and X-ray diffraction data are listed in Table I. No evidence of a second phase is apparent in the optical micrographs for the as-quenched sample, or for the specimens aged at 300 or 400°C; fine alpha particles can be seen in the specimen aged at 500°C. In the electron micrographs, visible equiaxed pocks appear in the as-quenched specimen, and, with increasing density, in the samples aged at 300 and 400°C. After aging at 500°C, the structure becomes markedly coarser and develops an oriented appearance of a second phase, coincident with the appearance of visible alpha particles in the light micrographs. These observations are confirmed by X-ray diffraction and hardness data. In these specimens, aged for 1 hr, the intensity of the omega pattern increases to a maximum at the 400°C aging temperature, corresponding to maximum hardness and the maximum density of pocks in the electron micrographs. At this point the beta phase shows a definite enrichment in Mn. At 500°C, little or no omega re-

Jan 1, 1959

By Thomas R. Mager

An in.t!estigation has been made of the equilibrium conditions at 1200°C in the reaction between hydrogen sulfide gas and sulfur dissolved in Fe-Si alloys From this the equilibrium constant, activity coefficient, and activity of sulfur in solution were calculated. A number of studies of the equilibrium of sulfur with iron and iron alloys have given closely agreeing results from which the activity and free energy of the dissolved sulfur may be found. Sherman, El-vander, and chipman1 discussed the significant researches of dilute solutions of sulfur in liquid iron prior to 1950, and the results of this study indicated that the relationship between the ratio of PH2S/PH2 in the environment and the percentage of sulfur in solution is not a linear one. Morris and williams2 studied the equilibrium conditions in the reaction between hydrogen sulfide gas and sulfur dissolved in liquid iron and Fe-Si alloys, and reported that silicon dissolved in iron has a pronounced effect on the equilibrium conditions. They found that the activity of sulfur in iron is increased by the addition of silicon. At a silicon content of 4 pet the activity coefficient of sulfur was about twice that for sulfur dissolved in pure iron. Sherman and chipman3 investigated the chemical behavior of sulfur in liquid iron at 1600°C through the study of the equilibrium: H2 + S = H2S; K = PH2S/PH2 . 1/as [1] From the known equilibrium constant of the reaction between H2, H2S, and S and the experimental data, the activity of sulfur in the melt was determined. They found that the activity coefficient of sulfur defined as fs = as/%s is increased by silicon and decreased by manganese. Morris4 and Turkdogan5 also reported that manganese decreases the activity coefficient of sulfur in liquid iron and iron-base alloys. A recent technique of sulfur analysis developed by Kriege and wolfe6 of the Westinghouse Research Laboratories permits an accurate sulfur analysis of 0.5 * 0.2 ppm in the range of 0.1 to 3 ppm, whereas in the range of 3 to 50 ppm the accuracy is ±1 ppm. This technique of sulfur analysis was utilized in this experiment. Previous unpublished data reported that sulfur analysis by the combustion technique was not accurate below 20 ppm. EXPERIMENTAL PROCEDURE Five 5-lb ingots of high-purity Fe-Si were prepared. Three of these ingots were prepared without the addition of manganese but with a variation of silicon contents from 2 to 4 pet. The remaining two ingots contained 3 pet Si with the addition of manganese. Ingots were made at each of three silicon levels: 2, 3, and 4 pet. No alloys were made with less than 2 pet Si since below approximately 1.8 pet Si the binary alloy exhibits a to ? transformation. The two additional ingots of 3 pet Si-Fe were made at each of two manganese levels: 0.20 and 0.50 pet. To minimize the effects, if any, of impurities on the activity of sulfur on Si-Fe, the best metals available were used for melting. All ingots were vacuum-melted in magnesium oxide crucibles. After obtaining samples for chemical analyses, the ingots were processed. This consisted of hot rolling and subsequently cold rolling the alloys. Each ingot was hot-rolled at 1000°C, reheating between every pass to minimize grain growth. All heating was done in a protective argon atmosphere. The slabs were hot-rolled to strips 50 mils thick. After hot rolling, all the material was pickled to remove the scale formed on the surface of the strip during hot rolling. The material was then cold-rolled to 12-mil strips. Single strips of the material used in this experiment were hydrogen-annealed at 1200°C for 16 hr in an alumina tube. Chemical analyses of strips M-1, M-3, M-4, M-7, and M-8 are given in Table I. Sulfur, silicon, and manganese analyses were made from the millings from the cold-rolled 12-mil strips. The oxygen analyses were made from slugs of the as-cast material. The hydrogen sulfide used in these experiments was supplied from cylinders containing a mixture of argon and 1 pet hydrogen sulfide. The parts per million of hydrogen sulfide were determined from the analysis of the exit gas of the annealing furnace during each anneal. The flow rate of hydrogen was approximately 1 liter per min in all anneals. The

Jan 1, 1964

By J. D. Lindner, Gene E. Roark

Waterflooding operations in the Langston-Kleiner field. Young County, Tex., are described. Widespread application of formation fracturing has been practiced in both producing and injection wells. Field performance data arc cited which indicate than no detrimental effect on sweep efficiencies and that probable benefits in imectivily have resulted from the fracture treatments. I N T R O D U C I O N This paper is a report on a waterflood operation which is being carried out in the Lanpston-Kleiner field located in Young County, Tex. The oil reservoir aflected by this flood operation occurs in a Strawn sand member at an approximate depth of 3.550 ft subsurl'ace. The operators of' the project are Kleiner Estate. Turncr. Fiske. and West who are hereinafter collectively referred to as the Operators. Although the operation is unusual in several respects, the distinctive feature of this flood has been the widespread application of hydraulic formation fracturing treatments as a means to improve productivity and injectivity of the wells. It shall he the purpose of this paper to present basic information regarding the reservoir characteristics. op- craling practices, and waterflood behavior so that conclusions may be drawn concerning the effects which the fracture treatments have had on the performance of this water flood to datc. DEVELOP MENT Development of the 3,550 ft Strawn sand reservoir occurred during 1951 and 1952. The early development occurred on the Langston and Davis leases which arc in the northern region of the Operators' holdings and the wells were drilled on 20-acre proration units according to the field rules. However, studies of the economics of this program. coupled with the decision to proceed with pressure maintenance by water injection. resulted in the adoption of wider spacing in the later stages of development. This variation in spacing is apparent upon inspection of Fig. I upon which only the 3,550-ft Strawn sand producing and injection wells have been located on the Operators' properties. The development to the north of the operators leases is Ihe Garvey Strawn field and that to the south is the Taylor Strawn field. It wits determined that unitization of the leases to he involved in the waterflood program was not feasihle. Consequently. a system of offset injection wells, or lease line injection wells, was adopted from place to place as required to protect correlative rights in the program. This resulted in a dispersed array of injection and producing wells with relatively close proximity of wells along lease line areas and wider spacing toward

Jan 1, 1956

By Stephen Krickovic

AS it is commonly understood in the bituminous coal mining industry, pillaring means removal, as completely as is practical, of all pillars formed in the development of headings and rooms on first mining. The degree to which this can be accomplished, termed percent of recovery, is of course dependent generally upon the physical conditions of the bottom and the overburden, the system of min-

Jan 1, 1956

CHARLES E. WILSON'S second quarterly report "Meeting Defense Goals" was encouraging on the outlook for the mining industry, as prolonged demand for minerals seems assured; but for the individual engineer things are not so rosy. Ten percent of the gross national product is going for defense but the gross national product has been increased by 9 pct since the national emergency was declared apparently a commendable rate of progress. The increased production does not seem to have had the stabilizing effect on prices it should and housewives have been revising domestic budgets upward on a quarterly basis. Government economists have reached the conclusion that more taxes and wage and salary freezing are necessary to counteract inflation.

Jan 8, 1951

By Robert C. Paddock

INTRODUCTION A way of producing 3,000 tpd from the El Mochito Mine was needed. Of this production, 2,000 tpd must come from the San Juan orebody. The original sub-level stoping method did not give satisfactory results due to ground instability, and the highly irregular ore/waste contacts encountered . The experience gained from the initial system helped guide research into the ground instability problem. Results from this work, combined with knowledge gained about the orebcdy configuration, defined constraints that were previously not fully appreciated. These constraints, and others, combined with objectives, were considered together to develop a new mining method. No single technique was found to be suitable, so a hybrid mining system was developed. A combination of ramping, cut and fill, and vertical crater retreat, with an option to use top heading and benching was developed. To complement the mining system, the type of equipment needed was decided upoun. Also, to support the mining system at this expanded rate of product ion, major modifications of existing infrastructure were required. THE EL MOCHITO MINE The El Mochito Mine, of Rosario Resources Corporation, has been in continuous product ion since 198. The mine began operations in April of that yeas at a rate of 100 tpd. The reserves in 198 were 100,000 tons of silver ore assayed at 1,250 grams per tonne. As of the end of 1979, the El Mochito orebodies have produced over 5.6 million tonnes of ore averaging 516 grams per tonne silver, 6.8 lead, and 7.8% zinc. Present ore reserves are about 7.9 million tonnes, averaging 138 grams per tonne silver, 4.6% lead, and 8.7% zinc, with minor quantities of copper, cadmium and gold. An expansion plan to increase mill production two fold to 2,500 tonnes per day is underway. This expansion will require the mine to produce 3,000 tpd. The mine consists of numerous orebodies, all of which have been mined to a certain extent. Of all the orebodies, the San Juan contains 8% of known reserves. This amounts to about 6.7 million tonnes. The significance of the San Juan orebody to the future life of the El Mochito Mine is obvious. If the required mine production of 3,000 tpd is to be sustained, the San Juan must be the source of the majority of that production. Due to the mineability and overall logistics concerned with the other orebodies, the San Juan must be able to reach and maintain a production rate of 2,000 tpd by 1982. GEOLOGY OF THE SAN JUAN OREBODY The El Mochito Mine is a classic example of a chimney replacement deposit in limestone. Similar deposits axe found in Mexico, at the Naica, Providencia, and Santa Eulia Mines. The El Mochito Mine is located at the south- western end of the Sula Valley on the western edge of the Honduras Depression in the Central Cordillera and Central Highlands of Honduras in a setting of Mesozoic sediments. The orebodies occur in a structural basin developed between NNE trending normal faults and apparently hinged on the south end. Topographically, the Mochito Basin lies between the uplifted Santa Barbara mountain in the west and the Palmer Ridge on the east. The San Juan orebody occurs near the intersection of the NE trending San Juan fault and the ENE trending Porvenir fault. The downward continuation of the orebody is controlled by the westward rake of these NW and N dipping structures. The discovery of the San Juan orebody is attributed to analysis of structural evidence of known ore deposits by in-company geologists. The composition of the San Juan orebody is primarily garnet skarn, with local concentrations of hedenbergite and magnetite. The economically important sulfide mineralization consists of (in decreasing abundance), sphalerite , galena, pyrrhotite , and chalcopyrite. There is some indication that a Cu-Ag mineral such as tetrahedrite may also be present. The skarns were formed by replacement of the original limestone by hydrothermal water migrating upward roughly along the intersection between the Porvenir fault system and the San Juan fault system. Textural evidence suggests that the orebody is a composite of several pulses of hydrothermal activity which would explain, in pat, the great irregularity of the contacts and the large horizontal variation in mineralogy. A general pattern of skarn types can be seen in the orebody, partially accounting for the observed lateral variation in grades. This zonation is very generalized, and one or more zones may be missing in any given locality. The orebody is almost invaxiably surrounded by a 2 cm to 25 cm zone of bustamite skaxn with low values. The border skarn is usually

Jan 1, 1981

By S. J. Rothman, J. J. Hines, D. Rokop, R. Bastar

Self-diffusion has been measured along each principal axis of mosaic-structured and relatively perfect a uvaniuln single crystals. The anisotropy reported before,' D[loo] = D[001] » D[010 , has been confirmed. and is shown to represent volume diffusion. Diffusion along the dislocations in the imperfect crystals increases the measured value of D significantly without changingr either the shapes of the penetvation plots or the anisotropy. SINCE a uranium is orthorhombic, the diffusion coefficients along the principal crystallographic axes need not be equal. A previous measurement of self-diffusion in three mosaic-structured a uranium single crystals1 showed that Dil00| =D[001 >>D[010 This result was deduced from penetration plots similar to those in Fig. 1. That is, the plots for diffusion along [loo] and [001] were the straight lines expected from the solution of the diffusion equation for the boundary and initial conditions of the experiment, while the plot for diffusion along [010] was curved so that the part near X = 0 had a much steeper slope than the straight lines did. The observed anisotropy could have been due either to volume diffusion or to diffusion along the very large number of dislocations in such crystals, according to the model proposed by aart.' The authors of Ref. 1 argued that the latter possibility was unlikely, but did not exclude it. To settle the question, a simultaneous measurement of self-diffusion in mosaic-structured and mosaic-free crystals was carried out. This paper reports the results, as well as a measurement of the temperature dependence of self-diffusion in a uranium. EXPERIMENTAL The single crystals of a uranium used in this experiment are listed in Table I, together with other experimental details. '(Mosaic structured" here means crystals grown by solid-state phase change.3 The Laue spots from such crystals spread over about 6 deg of arc, which indicates that the density of dislocations is very large. "Perfect" crystals are ones grown by Fisher's grain-coarsening tehnique; the Laue spots from these are quite sharp,4 which shows that the dislocation density in these crystals is much lower. All of the crystals were made from high-purity uranium; a typical analysis is given in Ref. 1. The actual diffusion directions were within a few degrees of the nominal. The thin layer-sectioning method was used. The experimental techniques were similar to those described in Ref. 1, except the sectioning. Crystals Za, 2b, 2c, 4a, 4b, and 4c were sectioned on a lathe. Crystals 3a, 3b, and 3c were sectioned by grinding on glass plates, with 1 p diamond powder in butyl alcohol as the abrasive. The use of glass plates eliminated the crowning noted in Ref. 1, and the use of butyl alcohol as a lubricant simplified the chemical processing of the sections. Material from the sides of these three crystals was removed by spark machining before sectioning. The sectioning of crystals 4a and 4c was botched. A small cylinder of metal was extruded from the center of crystal 4a while turning off material from the side of the sample. Crystal 4c was misaligned by 2.1 x 10"3 cm because the dial gage jammed during the alignment. Notwithstanding these errors, useful data were still obtained from these crystals. The points

Jan 1, 1967

By J. Chipman, J. B. Gero, T. B. Winkler

D. C. Hilty—This paper is a useful and timely addition to our store of quantitative data relating to manganese distribution between slag and metal in steel-making processes. For some time, many of us have suspected that the values of Kmn derived by Körber and Oelsen might be too low, and this paper now appears to confirm that suspicion. Application of the new constant to openhearth data should prove interesting. The manganese deoxidation curves of fig. 4 agree fairly well with direct measurements of isothermal solubilities of oxygen in liquid iron containing manganese that have recently been made at the Union Carbide and Carbon Research Labs., Inc. According to the solubility data just mentioned, however, the curves for 1550" and 1600°C lie much closer to each other than the authors have indicated. In other words, the solubility measurements suggest that the logarithm of the oxygen solubility is not a linear function of the reciprocal of the absolute temperature, as the authors have assumed for their calculations. It seems possible that this discrepancy may be due in part to the authors' use of the distribution coefficient, L,,, obtained from Taylor and Chipman's curve for the solubility of oxygen in iron as shown in fig. 2. Taylor and Chipman gave the equation of this curve as —6320 Log % 0 - ---T + 2.734 Their data, however, can be fitted equally well by a curve having the equation: 13.23 x104 1.18x10" Log % O = 36.350 -13.23x10 Moreover, this curve also fits the authors' oxygen distribution data somewhat better than does the linear curve of Taylor and Chipman. Its use in the derivation of Lo for calculation of the deoxidation curves by the authors' eq 15 causes the effect of temperature on the calculated curves of fig. 4 to agree quite well with the temperature effect that has been observed. An experimental determination of the temperature coefficient of the manganese reaction appears to be desirable. J. E. Stukel—Because the authors have done such an excellent job, my comments will be confined to additional information. Very shortly Professor T. L. Joseph and I will publish the results of a study of the reaction between molten manganese and silica. It was found that electrolytic manganese, melted in silica crucibles, reacted with the silica to form a silico-manganese alloy containing 18 pct silicon (1500°C) and a silica saturated MnO-SiO, slag. Therefore, the presence of silicon and its oxides in the Fe-Mn-0 system will affect the equilibrium. Carbon is also an important factor. The higher the carbon content of the iron the less ability manganese has to reduce silica. As a matter of interest, recently a study of the manganese equilibrium in carbon saturated iron and blast furnace slags was completed at Carnegie Institute of Technology. As a comparison to the present study, 2 to 5 hr were required to reach equilibrium and temperature was a much more important factor than slag composition in determining the (Mn)/(MnO) ratio. These results will also be published in the near future. It can be seen, therefore, that the results of this paper cannot be applied directly to openhearth studies without a degree of flexibility. J. Chipman (authors' reply)—With regard to the effect of silicon on the manganese constant, this effect is, of course, known. Much more data is needed in order to establish it accurately, and I hope we can look forward to having some accurate data on that. Mr. Hilty suggests that a three-term expression for the Taylor-Chipman solubility of oxygen in liquid iron might fit a little better than the two-term equation. I think that it would be too great a compliment to the precision of the data to employ a three-term equation, and I would still recommend the simple, two-term expression.

Jan 1, 1951

By B. A. Cheadle, K. P. Steward

Axial tensile, ring tensile, closed end burst, and free end burst tests were done at room tempe.vature and 300°C on three batches of Zircaloy-2 sheathing zuith different textures. Knoop hardness tests were also done on all batches. The mechanical properties of the tubes were largely dependent on the percentages of cold work, but were also markedly affected by the textures, particularly with respect to deformation behavio'r. The deformation behavior observed confirmed Picklesimer's predictions, zuhereas Knoop hardness results could be correlated with texture and yield strength anisotropy after the ,method of Wheeler and Ireland. From the mechanical properties, and from efjectiue strain values deterrlzined at the fractures using a photoqid technique, it zuas concluded that tubing witlz a single preferred orientation of radial basal poles best combines strength and ductility for any given deqee of cold work. THE mechanical properties required in collapsible Zircaloy-2 fuel sheathing for water-cooled power reactors are strength to resist wrinkling deformation by coolant pressure and ductility to accommodate a small amount of deformation in service without rupturing. Zircaloy-2 tubing during fabrication develops pre- ferred orientations of the a Zr grains due to aniso-tropic deformation behavior, and these textures markedly affect mechanical properties. Picklesimer' had predicted the deformation behavior of tubes with various textures, but the texture required to provide the optimum strength and ductility for a given degree of cold work has not been reported. To investigate this problem, tests at three transverse to axial stress ratios were done at room temperature and 300°C on three batches of Zircaloy-2 tubing covering a wide range of textures and percentages of residual cold work. Knoop hardness values were also measured to correlate with preferred orientation and yield strength anisotropy after the method of Wheeler and relland.' 1) MATERIAL For this investigation, three batches of tube-reduced tubing were chosen from the Zircaloy-2 sheathing produced for the Douglas Point Reactor. Individual tubes were 191/2 in. long, 0.600 in. OD, and 0.0165 in. nominal wall thickness. The identities of the batches, together with their textures, are shown in Table I. The tubes had the normal Zircaloy-2 composition3 of 1.5 wt pct Sn, 0.3 wt pct Fe, Ni, Cr combined with the following oxygen concentrations: Batch VII 1140 to 1390 ppm 0 Batch VIII 1400 to 1750 ppm 0 Batch IX 880 to 1320 ppm 0

Jan 1, 1968

By John H. Hollomon

THE interpretation of notched-bar impact results has been a matter of controversy since the introduction of more or less standard tests by Fremont,1 Charpy2 and others at the turn of the century. Many investigators3-l1 have contributed to the understanding of the significance of such tests. Several symposiums12,13 have been held with the express purpose of discussing the significance and interpretation of the impact tests. It is not the purpose of this paper to review all these contributions to the development of the knowledge on this subject, but rather to present an interpretation of notched-bar impact tests that appears to be in agreement with the available published data. Fundamentally, the interpretation discussed in this DaDer of the brittle failure of some steels in notched-bar impact test is similar to the qualitative analysis presented by Ludwik3 in the 1920's. Essentially, Ludwik stated that the function of the notch was to increase the tensile stress necessary for yielding, and that brittle failure occurred when the stress necessary for yielding exceeded the normal stress required for fracture (with no plastic de- formation). Ludwik, however, had no means of measuring this normal stress necessary for failure of a plastically* undeformed metal, therefore he could not extend his interpretation beyond the qualitative stage. Kuntze14 and recently MC- Adam15 attempted to determine the effect of deformation on the stress necessary for fracture by testing, in tension, specimens notched to various depths and angles. Because of the uncertainties in Kuntze's (and RlcAdam's) analysis of the stresses (which have been pointed out by SachsI6) and the inherent nonuniformity in the stress distribution in notched bars, the results of such investigations are difficult to interpret. A more direct method of measuring the effect of deformation on the fracture stress was suggested in previous papers17-l8 and has been utilized in the present investigation. The present paper concerns itself primarily with the behavior of notched impact specimens. The effects of strain rate, temperature, and stress distribution, which are discussed with reference to the impact specimen, apply just as well to the behavior of metal at the bases of notches in any engineering structure. All that is necessary is to determine the stress distribution in the structure at the base of the notches.

Jan 1, 1944

By J. L. Whitlock

An attached growth aerobic biological treatment process has been developed at Homestake Mining Co.'s Lead operation which not only oxidizes free and complexed cyanides, including the stable iron complexed cyanides, but also thiocyanate, and the oxidation byproduct ammonia. Through the employment of a mutant strain of bacteria which has been gradually and specifically acclimated to the waste, these potential pollutants are mineralized to relatively harmless sulfates, carbonates, and nitrates. The resultant effluent, through toxicological testing, has been shown compatible with the receiving stream, which serves as a cold water marginal trout fishery.

Jan 1, 1985

By Zay Jeffries

A MORE complete interpretation of the amorphous theory in metals is given than has heretofore been offered. It is believed that Le Chatelier, Tammann, and Heyn, at present the ablest opponents of the amorphous theory, will not he able longer to continue their beliefs that surface tension alone can account for all the observed variations in the properties of single constituent metals. It is strongly advocated that the properties of any solid substance be studied from the standpoint of the number of constituents present, the quantity and arrangement of each constituent, and the properties, of each constituent. Each deformable crystalline constituent by plastic deformation will produce amorphous material, thus changing the properties. Considerable attention is given to the variations in properties of the amorphous and crystalline phases of any substance. These are summarized as follows: 1. The cohesion of the amorphous phase of a substance is substantially zero at the melting point while the cohesion of the crystalline phase is considerable at the melting point. With decrease in temperature, the cohesion of the amorphous phase increases at a faster rate than that of the crystalline phase; this differential rate of change of cohesion holds between absolute zero and the melting point. At a certain temperature

Jan 2, 1919

By David J. Selleck, Eugene P. Pfleider

9.61. Introduction. Open pit mining methods produce more than 80% of all raw materials today in the United States. Much of this comes either from properties that formerly employed underground methods and were converted to open pit or from mines that ultimately must go underground when the economic stripping limit is reached. Generally the ores are transported over large vertical distances and techniques have been developed to do this economically. One approach is to combine conventional surface trucking, over relatively level roads, with the use of gravity and underground facilities. There are various modifications, depending upon the character of the orebody and the topography. Several schemes, as used in Sweden, Canada, and the United States, merit describing. One of the critical problems involved in the transference of ores from surface to underground is that of flow of bulk solids. Must it be crushed? Will it hang up in the transfer? What size and inclination of ore pass are required. How is the ore best fed onto the transporting device underground? As an example, the planning engineers for the Carol Project of the Iron Ore Company of Canada faced these problems in making their designs for the production and transportation of some 55,000 tpd from their Smallwood Mine in Labrador. Other operations, facing somewhat similar conditions, used other approaches of interest. This chapter describes some of the factors involved in the design, construction, and operation of a combination surface underground transportation system as applied to open pit mining operations. 9.62. Tunnel-Ore Pass Systems. The type, shape, dip, and size of the orebody, as well as the surface topographic features, generally estab-

Jan 1, 1968

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from September 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining-maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued, and similar material, which will be classified, indexed, and, made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 6, 1914

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from Sept. 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library, freely, and assurance is given that most careful service will be rendered to them.

Jan 5, 1916

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week days, except holidays, from September 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The, time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued,-,and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 5, 1914

By S. C. Sun, D. R. Mitchell

T LTRASONICS can be used to deslime and up-grade ores, such as tungsten and tin, which slime excessively with high losses of value in the tailing and are difficult to deslime with conventional methods. Experimenta] work has been performed with a test-tube size ultrasonic classifier. Larger equip-

Jan 1, 1957

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from September 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Membebs of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining-maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can he of service to the Library by forwarding copies of mining-reports, maps privately issued, and. similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will he welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 4, 1914