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By W. J. Wrazej

THE measurements on the formation of multi-layered scales on pure iron1 and the metal -lographic examination of the produced layer of FeO, Fe,O,, and Fe2O3 shown in micrographs2 throw much interesting light on this apparently well-known subject. Professor Paidassi announced2 that in a few months7 time further results are going to be published with regard to the growth of Fe2O3 and Fe2O3 layers on an Armco iron as a function of temperature. Because of the very thin layers of Fe2O3 which are shown by Paidassi (Fig. 10 of ref. 2) when samples were scaled in air at 700°C for 4 hr and because this is not in agreement with the present author's previous observations, the following experiment was recently carried out. Polished cylindrical samples 13/64 in. in diam and 1/4 in. long from electrolytic iron used for spectro-graphic work (Hilger, H.S. Iron rods, F.693) and an Armco iron sample 1/4 in. in diam of the same length were suspended in a muffle furnace on Nichrome wire and annealed in air for 4 hr at 700°C 5OC. Because of the known easy peeling off of the Fe2O3 layer which is mainly in the form of powder (purple red dust on the surface) the samples were protected against any draft and shock. After annealing, the samples were cooled in air and placed in the mount-

Jan 1, 1954

By J. H. Swisher

ALUMINUM deoxidation equilibrium in liquid iron has been the subject of many investigations. Sawamura and Sano1 have written a critical survey of the literature on this subject and consider the data of Gokcen and chipman2 and of d'Entremont, Guernsey, and Chip-man3 to be most reliable. The present study was undertaken to check these data and extend the range of the experiments to lower temperature. The experiments consisted of equilibrating 5-lb Fe-Al melts with recrystallized alumina crucibles at 1580o + 10oC, and analyzing the solidified ingots for aluminum and oxygen. The electrolytic iron stock contained 100 ppm C, 20 ppm 0, and trace amounts of other elements.* The stock was induction-melted in an atmosphere of 5 pet H2 in argon to attain equilibrium between the melt and the crucible. The temperature was measured with a W, 3 pet Re/W, 26 pet Re thermocouple, and the equilibration time was about 4 hr. The results are plotted in Fig. 1 along with curves obtained from the data of d'Entremont et al.,3 for temperatures of 1740o and 1910°C. The present results can be seen to be consistent with the previously reported high-temperature data. The reaction under study is AI2O3 (s) = 2 Al (l) +3O [1] for which the deoxidation product is Kl =[% Al]2 [%O]3 [2] (Under the experimental conditions, Fe A12O4 is not expected to form.4) In Fig. 2, values of log Ki evaluated at 0.01 pet A1 are plotted against 1/T, using data obtained from all the investigations under consideration. The deoxidation product is plotted in Fig. 2 in lieu of the equilibrium constant (normally obtained by evaluating Ki as pet A1 — 0) because of the uncertainty involved in extrapolating to zero concentration. The difficulty in extrapolating the present data for 1580°C is apparent curvature in the log Ki vs pet Al plot. This curvature is perhaps due to the uncertainty in oxygen analysis for concentrations of 5 ppm and below. For the data of Gokeen and chipman,' the extrapolation is also difficult because of experimental scatter. The line drawn through the points plotted in Fig. 2 may be represented by the equation:

Jan 1, 1968

NEW MEMBERS The following list comprises the names of those persons who became members during the period Dec. 10, 1918, to Jan. 10, 1919. ADAMS, W. W., Mine Supt., Cia. Minera Paloma y Cabrillas, Higueras,,Coah., Mexico. ANKENY, CLEMENT W., Golden Cycle Min. & Reduction Co., Colorado Springs, Colo. ARGUE, WILLIAM H Mech. Engr., Ohio Brass Co;, Mansfield, Ohio. ARTHUR, WALTER Chem. and Met., Garford Motor Truck Co., Lima, Ohio. BANGSER, WILLIAM, Supt., Treatment Dept., Bethlehem Steel CO., Bethlehem, Pa. BEACH, C: S Asst. Supt. and Engr., Kemmerer Coal Co., Frontier, Wyo. BEAVER, A. B., Chem. and Engr. of Tests, National Cash Register Co., Dayton, Ohio. BORRIES, WILLIAM J., Min. Engr., Gen'l Mgr., American Zinc & Slate Co., Picher, Okla. BOTSFORD, CLARENCE A., Acting Gen'1 Mgr., Mogollon Mines Co., Mogollon, N. M. BOTSFORD, GEORGE B., Asst. Supt., Sunrise Iron Mines, Colorado Fuel &. Iron Co., Sunrise,. Wyo. COLLINS, GEORGE N., Mine Shift Boss, New York & Honduras Rosario Min. Co., San Juancito, Honduras, Central America. COTS, HOMER, Resident Engr., Arkansas and Oklahoma Dist., Central Coal & Coke Co., Huntington, Ark. CRICHTON, WALTER CREIG, Min.. Engr., 20S Charleston National Bank, Charleston, W. Va.

Jan 2, 1919

By B. Habermann

Artificially consolidated sand models, representing one-quarter of a five-spot, have been developed and used to study factors aflecting misciblt. displacrmenr. Sweep efficiency at breakthrough, size of the mixing zone between two miscible liquids and per cent area contacted by drive after breakthrough were determined tor the high mobility ratios encountered in actual resvrvoirs. Quantitative relationships between the degree of viscous fingering and mobility ratio were obtained by measuring the length of the fluid interface. Scaled miscible-slug experiments, supported by field evidence reported in the literature, have shown that when the slug is followed by dry gas the process is less efficient than expected. In addition to low areal sweep efficiencies encountered for high mobility ratio displacements, the effectiveness of a miscible slug is greatly reduced. This is caused by an accelerated growth of the mixing zone between the driving and the displacing fluids. INTRODUCTION Considerable interest in miscible displacement as a secondary recovery process has been shown by the oil industry in recent years. In addition to extensive laboratory investigations, numerous field operations have been initiated so that 39 miscible displacement projects had been reported' in the United States by early 1959. By far the most popular approach in these projects is the use of an LPG slug followed by dry gas. Laboratory tests have indicated that with a small miscible slug, amounting to several per cent of the hydrocarbon pore volume, practically 100 per cent recovery of the oil in place can be achieved and that all of the slug material can be recovered by a subsequellt gas drive. However, these experiments were conducted on small-diameter long cores that can be considered as essentially uni-dimensional reservoirs that do not represent actual field conditions. It soon became apparent that the inherently adverse mobility ratios existing in the reservoir cannot be ignored in any miscible displacement field project. When a less viscous fiuid such as an LPG slug drives a more viscous reservoir oil, fingers develop that reduce the areal sweep efficiency. The slze of the miscible slug to be used is a subject of some controversy. It has been proposed that the size of siug needed be calculated by setting lengths of the mixing zone proportional to the square root of the distance traveled. This proposal is based on experimental evidence' and theoretical considerations"' in which fingering was not a factor. A prerequisite for successful application of the miscible displacement process to field operations is a better understanding of the following factors. L What is the effect of mobility ratio on the rate of deterioration of a miscible slug? 2. How large a slug should be used for given reservoir conditions? 3. What is the sweep efficiency? The purpose of this investigation was to provide some additional laboratory data that should help to answer these questions. More specifically, it was intended to study more quantitatively the effect of viscous fiinger-ing, mobility ratio and slug size on the efficiency of this relatively new secondary recovery process by means of experiments on thin, horizontal, porous medium models.

By J. A. Herbst, D. W. Fuerstenau

This paper examines the zero order production phenomenon in the context of the size discretized batch grinding model. A restrictive interrelationship between the selection and breakage parameters of the model, which is mathematically sufficient to ensure zero order behavior, is delineated. Based on this interrelationship, a scheme is developed for predicting the values of the selection and breakage parameters for all size fractions from a minimum of experimental data. To test this scheme, dolomite was ground in a laboratory batch ball mill. Successful simulation of the comminution behavior of this system was achieved using the batch grinding model with the parameter values obtained from the proposed scheme. Historically, a preponderance of comminution research has centered on attempts to relate breakage energy to the performance of comminution machines. Concomitantly, grinding data were interpreted almost exclusively in terms of inherently empirical energy-size reduction relationships1-3 or "laws of comminution"4- 6 which were based on highly oversimplified descriptions of the fracture process. In some instances, these relationships provide a crude basis for the correlation of experimental data, but, invariably, this approach is inadequate for meaningful process simulation. The control and optimum design of comminution circuits require a mathematical model capable of depicting the size reduction behavior of every size fraction for grinding conditions of technological importance. Energy-size relationships do not provide this detailed information. For example, an energy-size analysis for batch ball-milled dolomite has recently been completed in the authors' laboratories.7 This analysis provided a satisfactory correlation between the hypothetical size modulus, which characterizes only the finer portion of the size distribution, and the input energy. However, this relation did not constitute an adequate description of the complete system. In general, one of two distinct viewpoints toward simulation has been adopted in recent comminution research. The first approach focuses on the fracture of single mineral specimens, with the essential aim of representing the over-all process in terms of the breakage characteristics of individual particles and the characteristics of the stress field which the particles experience within the particular size reduction device. As illustrated by Harris's review,' the actual incorporation of single-specimen fracture information into a description of the behavior of a multiparticle comminution system has seldom been attempted. The only model to accomplish this incorporation was the one developed by Schönert.8 The Schonert model treats single-passage grinding machines in terms of a distribution of effective loads acting on a particle, a distribution of required particle breakage energies, and the breakage product distribution. However, the use of single-particle fracture behavior to derive models of the size reduction process is at present limited to machines in which the particle residence time is approximately equal to the time required to apply stress. As a result, Schönert's analysis cannot be used to advantage to simulate the complex environment which prevails within a tumbling mill. For multiple-passage systems a second approach to the description of comminution processes has been more fruitful. This approach entails the formulation of a mathematical model which is phenomenological in nature in that it lumps together the entire spectrum of stress-application events which prevail in a system under a given set of operating conditions. The appropriately defined average of these individual events is then considered to characterize the over-all breakage properties of the device. Thus, to analyze the performance of a tumbling mill, the manner in which the particles of a particular size (or size fraction) are stressed need not be distinguished. Instead, a single parameter is assumed to represent the resistance of that size to fracture, given the average grinding environment which exists in the mill. The isolation of such a parameter and a related set of quantities, which constitute the breakage product size distribution for the average event in this size fraction, allows the formulation of physically meaningful descriptive equations capable of yielding precise and detailed information for simulation.

Jan 1, 1969

The War Department is appealing to skilled workmen and scientifically or technically trained men to enlist in any one of a large number of engineering troops needed for immediate action in France. Any registrant under the selective service law, who has not actually been called to service, may be immediately inducted into an engineer organization at his own request. Application for induction should be made to the Chief of Engineers, giving a complete statement of the applicant's qualifications. Any man who is physically qualified, between the ages of 18 and 21, or between 31 and 40, may voluntarily enlist for an engineer organization, provided he proves to the recruiting officer that he is experienced or skilled in any engineering trade, or is a handy main who is' especially suited for engineering work. There are about 600 recruiting stations in the United States, and an officer at any one of these will enlist a candidate for an engineer organization if he is suitable. Enlistment is in the grade of private. Subsequent promotion to the rank of non-commissioned officer is secured by merit. It is intended to fill many of the vacancies which will occur from time to time among the commissioned officers by selection from the ranks. A few of the special services, of most interest to mining and metallurgical workmen, urgently needed by the army, are as follows: Crane Operating and Maintenance Regiments; Depot Detachments; Electrical and Mechanical Regiments; General Construction Battalions; Mining Regiments; Quarry Regiments; Battalions for the construction, maintenance, and operation of railways; Road Building Battalions; Sapper Regiments; Supply and Shop Battalions; Surveying, Ranging and Map Reproduction Regiments; Water Supply Companies; and many others. All of these organizations will be assigned to such duties as competent

Jan 4, 1918

By C. A. Heiland

THE investigations described were made on a portion of Clear Creek basin near Golden, Colo. (A portion of the area under survey is shown in Fig. 1. The photograph was taken in the vicinity of station No. 2 of Line II.) Three principal purposes were in the minds of the investigators: 1. To repeat with modern, more sensitive and more reliable instruments magnetometric placer investigations previously made. 2. To disprove the recently advanced theory that deposits of the glacial period have no pronounced magnetic effects. 3. To develop in detail the theory of the magnetic effects produced by placer deposits. Six years ago, the first magnetic observations were published, which proved that it is possible to locate gold-bearing channels with relatively crude instruments.1 Two years ago, K. C. Laylander published results obtained with similar instruments.2 The measurements of the latter were discussed by the senior author of this paper.3 At that time, however, the material available for such a discussion was somewhat scarce and not made with the most modern magnetic instruments, although very brilliant results were obtained. Therefore, the senior author felt that magnetic investigations should be made on very clear geologic conditions with the most modern instruments.

Jan 1, 1928

By William C. Hagel

Oxygen-18 exchange between gaseous oxygen, held at a pressure of 125 mm Hg in a PL-IORh chamber, and splzeres of a Fe2O3 containing three or less grains was determined from 9000 to 1250°C. Isotope equilibrum on crystal surfaces appears to be quickly established, and the rate-determining factor is self-difiusion confbvrning to the relation D = 2.04 esp(- 77,900/RT) sq cin sec-'. Changing sphere diameters caused no detectable variation in diffusion coefficients. Oxygen ions diffuse faster than cations at low temperatures, but a crossover may occur at about 1150°C. INVESTIGATIONS by Davies et al.' and Himmel et al2 have suggested that the mechanism of iron oxidation above 600°C involves a predominance of cation migration in the wüstite (FeO) and magnetite (Fe301) layers and oxygen-ion migration in the hematite (a Fe2O3) layer. Evidence for little cation migration during hematite growth consists of: 1) the disappearance of radioactive-silver markers, presumed to vaporize from the oxide-gas interface, and 2) a large discrepancy between parabolic rate constants for magnetite oxidation and those calculated from Lindner's3 data for cation self-diffusion, D:, using Wagner's theory.4 Reversing the calculations gave anticipated self-diffusion coefficients, D:, for oxygen ions of 3.6 x 10-9 sq cm sec-1 at 1100°C and 5.9 x 10-10 sq cm sec-1 at 1000°C. Since then Kingery et a1.5 reported three values for oxygen-ion diffusion in polycrystalline, sintered hematite. These were obtained near 1200°C, at an oxygen pressure of approximately 150 mm Hg, and could be represented by the Arrhenius expression, Dg = 1 x 10 11 exp(-146,000/RT) sq cm sec-1. Extrapolation to temperatures below 1100°C infers that oxygen ions are less mobile than cations. This contradicts the aforementioned oxidation evidence and also coble7s study of the initial sintering of hematite. From the latter, apparent diffusion coefficients for the slowest rate-controlling species could be calculated, and fair agreement was found with an extension of Lindner's data for cation diffusion. Fig. 1 depicts such comparisons graphically. Three points have been included for the determinations of Himmel et al. on cation diffusion in large, natural hematite crystals surrounded by pure oxygen at atmospheric pressure. No dependence on crystal log raphic direction was noted. Since the value of 10-l4 sq cm sec-' at 1000°C actually represents an upper limit, one might interpret that there is a small decrease in D: when single crystals are employed. On the whole, however, cation diffusion appears relatively well-defined,* while the few results tension to lower temperatures. After having gained experience measuring oxygen-ion diffusion in certain glasses7 and in the corundum oxide, a Cr2O3, the purpose of this work was to determine D; values for hematite and thus possibly assist a mechanistic understanding of the kinetics of the oxidation and reduction of solid iron oxides. I) EXPERIMENTAL PROCEDURE A) Material. Hematite powder of moderately high purity was received from the Columbian Carbon Co. An accompanying lot analysis listed 0.03 H2O, 0.008 weight percents, with the remainder Fe2O3. Subsequent treatments were ball milling, drying, prepressing, and hot-pressing for 60 min at 1350°C under 5000 psi. Since graphite dies coated with a slurry of alumina were used for hot-pressing, the surrounding atmosphere at temperature was sufficiently reducing to form some magnetite on the outer surface of each cylinder. After removing any attached alumina, a stabilizing anneal of 50 hr at 1300°C in oxygen was added. The final product was nonmagnetic and exceeded 97 pct of the density (5.24 g cm-3) usually given for FezO3. On polishing cylindrical ends, counts were made of the number of grain boundary intercepts per

Jan 1, 1967

By J. E. Berg

THE geology of the Coeur d'Alene mining district is so familiar to every one interested in mining that I will only note as an introduction that the main producers are mines whose orebodies lie in the Revett or Burke quartzites ; that the known orebodies in the eastern part of the district all lie north of the Osburn fault; that the Prichard formation is quite generally looked upon as being unfavorable for lead deposits ; that the monzonite intrusive mass extending north from Gem to Sunset Peak, and over into Cedar Creek divide, is considered to have been the prime agent in the crea-tion of our orebodies, and that diabase dikes are a quite common feature at most of the properties with which I am familiar. Some of the exceptions to these statements may be mentioned. The Interstate-Callahan mine is considered the exception disproving the alleged relation between large ore-deposits and the Prichard formation, but this property was primarily a zinc producer, with lead secondary, though of sufficient tonnage to be a valuable product. A second interesting occurrence in the Prichard worth calling to your attention is the Jack Waite property, on Tributary Creek, north of Murray. This vein lies at a low horizon in the Prichard forma-tion, and the ore differs essentially from others in the same horizon elsewhere in that it is a clean, medium to coarsely crystalline, lead ore carrying very little zinc, about one ounce silver to ten units lead, and is accom-panied by a clean quartz gangue or vein filling. I believe that quartz was the primary mineral in the fissure, and that the lead ore was deposited in the vein as a replacement of the quartz.

Jan 7, 1927

W. P. PUTNAM,. Detroit, Mich.-There is one company that is heating these tubes in an upright position by passing electrical energy directly through the tube itself. The lower connection is attached to an indicator, which shows the point at which the steel passes through the critical range At that point the clamps are released and the tube is dropped into a well of oil. This method simplifies the heat treatment of tubes in long lengths. H. J. FRENCH.-I am not entirely familiar with. the method outlined, but it appears to have one serious disadvantage; that is, the length of tubing that is directly connected with the electrical contacts is wasted and must be cut off due to either heavy oxidation or burning. That is a serious difficulty, if true in all cases, and cannot be overcome, inas-much as it is very difficult to draw long tubes of thin wall. Having once obtained a lot of tubes, to cut, say 14 ft. in length, there is often little excess metal available to discard. Am I correct concerning the burning or heavy oxidation of the metal where it comes in contact with the tube.

Jan 12, 1919

By Robert Peele

TWO outstanding members of the Institute will be honored at the Annual Meeting this month: Robert Peele, who will accept his election to the small group of Honorary Members; and Clinton Hoadley Crane, president of the St. Joseph Lead Co. and William Lawrence Saunders Medalist for 1936. Eminence in the profession character, interest in Institute activities, and general recognition as a gentleman and a friend by so many people, have contributed to the election of Professor Peele. The Saunders Medal is for "achievement in mining." In awarding it to Mr. Crane the citation reads "For distinguished achievement in the successful development and operation of low-grade lead mines."

Jan 1, 1936

By H. P. Croft

[ ] Professor Hibbard's paper presents a very interesting theory concerning the influence of texture on the tendency of brass tube to stress-corrosion crack. I should like to present the result of some work done in 1941 which may throw further light on the subject. In the first place, in regard to his review of the influences of grain boundaries, we not only confirmed the findings which he quoted, but also were unable to crack single crystals of beta brass in the standard mercurous nitrate test in 50 hr under loads up to 18,500 psi. Samples containing two or more crystals of beta brass always cracked at grain boundaries and generally followed the same pattern as for alpha brass, although cracking occurred sooner than in alpha brass under the same conditions. Such a specimen is shown in Fig 4. Second, at the possible risk of repetition, we should like to call attention to the reported role of grain size as influencing the tendency to stress-corrosion crack. This phenomenon, originally mentioned by Dr. Allan Morris in the Transactions, AIME, 1931, is illustrated in Fig 5, showing the effect of variations in grain size on the tendency of drawn brass wires to crack under load in the mercurous nitrate solution. This was taken from my work published in Proceedings A.S.T.M. 41, (1941), 905.

Jan 1, 1948

By T. A. Rickard

The history of this State is that of one generation. Thirtysix years only have elapsed since the birth of that beneficent industry whose footsteps were the first to traverse the wilderness of the prairies and penetrate the solitude of the mountains. So soon is history made. The men who halted on the rolling plain where Denver now stands and gazed westward at the snow-clad ranges in eager questioning of their possibilities of golden wealth, have lived to see a noble city built where once their camp-fires burned, and have participated in the discovery of a magnificent series of productive mines amid the mountains which seemed at that time the Ultima Thule of their pilgrimage. To those who investigate the workings of our complicated mining and metallurgical industries, the story of their evolution from humble beginnings will appear an instructive romance. The record that tells it presents features common to the growth of modern mining regions, but also bears aspects peculiar to

Jan 1, 1897

By Allen Rogers

THERE are few natural monopolies comparable with the nitrate industry. Perhaps the only other one is, curiously enough, also an essential fertilizer material, viz., potash, of which the Germans have heretofore held practically a-monopoly due to the existence in their territory of the most important known deposits of potash salts. And although nitrates in minute amounts are found in many desert regions, the only deposits callable of being worked commercially exist in Chile. Combined nitrogen in the oxidized form is an essential for plant life. Nature provides it mainly through the agency of nitrogen-fixing bacteria. But where lands are cropped artificially this supply is too small; and gradually the nitrogen supply becomes exhausted. In order to continue farming, it is necessary to furnish a supply of nitrogenous plant food, and this is clone by putting on various substances containing combined nitrogen. These consist of various animal wastes, ammonium sulphate, the ammonia of which is obtained in the destructive distillation of coal, and Chile saltpeter. The latter is immediately available as a plant food, the nitrogen being in the required form. The other substances must oxidize before they are available. Besides its use as a fertilizer, Chile saltpeter is the source from which the bulk of the nitric acid of commerce is derived. The use of nitric acid in the manufacture of almost, all modern explosives is, of course, well known.

Jan 2, 1918

By L. J. M. Smits

A theoretical equation is developed describing membrane potentials of shaly sands as a function of the cation-exchange capacity per unit pore volume of the rock and saturating water salinity. This equation is based on the same simple physical model as that employed earlier7 describing the electrical conductivity of shaly sands. Experiments conducted with NaCl solutions showed that the equation is obeyed, except in the case of saturated salt solutions where minor deviations were observed. A possible explanation is given for this discrepancy. As the clay content and the porosity of shales may vary appreciably, shale membrane potentials also vary. It was found that membrane potentials of shales can be calculated accurately with the aid of the same theory. Consequently, changes in membrane potentials can be accounted for by simple measurement of cation-exchange capacities per unit pore volume of both shales and shaly sands. Charts are given to facilitate interpretation of the electrochemical part of the SP in terms of cation-exchange capacities and the salinities of mud filtrate and formation water. INTRODUCTION A spontaneous potential (SP) log is a record of the way in which the electrical potential of a sonde varies as it passes down a borehole. Such variations frequently reflect rock texture, e.g., permeable beds intercalated in an impermeable series often are indicated by a sharp change in potential. Nowadays it is recognized that SP logs may be interpreted in terms of formation-water salinity and formation shaliness. The four sources of the SP are illustrated in Fig. 1. El and E4 represent streaming potentials generated by the flow of mud filtrate through mud cake opposite permeable formations and through shale, respectively. An extensive review of the literature on the evaluation of these streaming potentials is given by Lynchl and will not be discussed here. The remaining part of the SP generally is called the electrochemical potential, which is divided into two parts: a membrane potential across the shale (E3, Fig. 1) and a membrane potential in the permeable sand at the diffusion boundary between formation water and mud filtrate (E2, Fig. 1). It was found by wyllie2 that the membrane potential across the shale, E3, is the most important contribution to the electrochemical potential, the shale acting as a semi permeable membrane. When the sand is clean it does not influence the diffusion process, so E2 equals the value of the so-called liquid-liquid junction potential observed when the two solutions diffuse freely into each other. When the sand contains clay, however, this interferes with the diffusion process and affects the diffusion potential generated. The greater the proportion of clay, the stronger this effect will be. Wyllie,3 Doll4 and Poupon et al.5 took this effect into account theoretically, starting from a physical

Jan 1, 1969

All the TECHNICAL PUBLICATIONS and CONTRIBUTIONS published in 1934 are available at Institute headquarters, unless otherwise noted They are also on file in many public, university and technical libraries and, when so indicated in the list, may be found in the TRANSACTIONS Copies of the TECHNICAL PUBLICATIONS have been mailed to those members of the Institute who are registered in the different classes A-Metal Mining, B-Milling and Concentration; C-Iron and Steel Division; D-Nonferrous Metallurgy; E-Insti¬tute of Metals Division; F-Coal Division; G-Petroleum Division; H-Nonmetallic Minerals; I-Mining Geology; J-Mineral Industry Education Division; K-Mining Administration; L-Geophysical Prospecting Other members may obtain copies by writing to the Secretary Copies of CONTRIBUTIONS may also be obtained from the Secretary's office Additional copies are sold at the rate of 1 cent per page, minimum charge, 25 cents Nonmembers may purchase the papers at the prices mentioned

Jan 1, 1935

By Glenn C. Waterman

Richard Strong (Oliver Iron Mining Div., U. S. Steel Corp.)—Mr. Waterman states (p. 59, Trans., January 1954): "Core-sludge combining factors have been calculaied for any combination of core-sludge recovery on the basis of several logical assumptions: 1—The sludge sample loses reliability geometrically as sludge recovery drops. 2—The sludge sample should not be used if the percentage of sludge return is less than the percentage of core recovered. 3—A core sample should receive a weighting at least equal to the percentage of core recovery." Assumptions 1 and 2 seem justified at Chuquicamata and most geologists would agree to the validity of assumption 3. However, contrary to the statement quoted above, the core sample does not in general receive a weighting at least equal to the percentage of core recovery when the Chuquicamata methgd is used. Furthermore, the basic Chuquicamata method is identical to the Longyear or relative volume core-sludge assay combining method. Finally, the Chuquicamata method does not, in its present form, reflect true geometric loss in sludge sample reliability according to the relationship L = AR (N-1) The basic equations representing the two steps of the Chuquicamata method can be combined algebraically as follows (using the symbology of the original article except as noted): Vol A + B Assay 2 = ASA = Assay 1 Vol A VolB Core Assay [I] Vol A CA.F + ASA (100 —F) Combined grade =[21 100 Pct where F and (100 — F) are the core and adjusted sludge assay factors from Fig. 3. Substituting Eqs. 1 and 2 and collecting terms Combined grade = Vol B Vol A + B CAF (100—-F) + Assay 1 (100-F) Vol A Vol A 100 pct Eq. 3 is a unified and general statement of the Chuquicamata method. The true core factor includes not only the factor F from Fig. 3 but also the quantity VolB ------------- (100 — F), which is implicit in the value of Vol A the adjusted sludge assay. This quantity is real and positive for all values of F and core recovery less than 100. Therefore the true core factor is always less than F except when F is equal to 100. If sludge recovery is 100 pct, Eq. 3 can be further simplified as follows: Let F = percentage of core recovered. Let Vol A = Vdh (100 Pct — Pct CR) where Vdh is the total volume of the sampled interval and let Vol B = (Vdh — Vc.) Pct CR where V, is the core volume in the sampled interval at 100 pct core recovery. Then combined grade = Vo V. CA Pct CR- + Assay 1, 100 Pct — Pct CR Vdh Vdh [4] 100 Pct Eq. 4 shows that when sludge recovery is 100 pct the laboratory sludge assay receives significant weight in the Chuquicamata method, even at 100 pct core recovery. The maximum weight assigned to the laboratory sludge assay depends on drillhole size, as follows: Eq. 4, with suitable changes in symbology, is identical to Royce's formula 8,' which is a statement of the Longyear or relative volume method of combining core and sludge assays. If Mr. Waterman's assumption 3 is of paramount concern to the geologist, the Royce method (for core recoveries of 60 pct and above) or a method employing the percentage of core recovered as a core weighting factor are the only recognized methods known to the writer which achieve the desired result. A modification of the latter method embodying Mr. Waterman's assumptions 1 and 2 would result from applying the factors from Fig. 3 directly to the laboratory core and sludge assays.

Jan 1, 1956

By J. T. Williams

The equilibria in the V-Zr alloy system were investigated by solidus temperature determinations, thermal analysis, dilatometry, electrical resistance measurements, microscopic examination, and X-ray diffraction analysis. There is a eutectic reaction at 1230°C between a compound, V2Zr, and a solid solution containing 10 pct V in ß zirconium. V2Zr decomposes at 1300°C into liquid and a solid solution containing about 10 pct Zr in vanadium. The eutectic composition is probably about 30 pct V. A eutectoid reaction between V2 Zr and a zirconium takes place at 777°C at a very high rate. The eutectoid composition is 5 wt pct V. The limit of solubility of zirconium in vanadium was estimated to be 5 pct at 600°C. No attempt was made to determine the liquidus for the system. THE recent availability of large quantities of high purity zirconium has stimulated the study of zirconium binary systems. The equilibrium diagram for the V-Zr system has received little attention, however. Wallbauml appears to have made the first report concerning the equilibria in these alloys. He reported the existence of a compound, V2Zr, having the MgZn2 ((214) type of structure with a, = 5.277 kX and c° = 8.647 kX. Anderson, Hayes, Roberson, and Kroll2 made a survey of some potentially useful zirconium binary alloys and found that zirconium probably dissolves a small amount of vanadium. They reported the probable existence of a compound between the two elements and suggested that the zirconium-rich solid solution undergoes a eutectic reaction with this compound. Pfeil," in a critical review of the existing information, estimated that the solubility of vanadium in zirconium is less than 4.7 pct and probably less than 1.8 pct. Rostoker and Yamamoto' proposed a partial diagram for the V-Zr system in a survey paper on vanadium binary alloys. Their diagram indicates the compound, V,Zr, a eutectic reaction at 1360°C, a peritectic reaction at 1740°C, and a limit of solubility of zirconium in vanadium of about 3 pct. They obtained no information on the equilibria in the zirconium-rich alloys. In view of the potential utility of the V-Zr alloys and the incomplete knowledge concerning the equilibria in the system, an attempt was made to establish the constitutional diagram. Preparation of the Alloys Raw Materials: The vanadium for making up these alloys came from the Electro Metallurgical Corp. Zirconium came from two sources. In the beginning of the investigation, sponge zirconium from the Bureau of Mines was used in making some of the alloys. Later, iodide metal made at the Westinghouse Atomic Power Development Laboratories became available. This material was used in the preparation of all the dilatometric and resistance specimens and about two-thirds of the solidus temperature specimens. A typical manufacturer's analysis of the vanadium is shown in Table I. No other analysis of the vanadium was made. The metal contained a dispersed second phase and did not have a sharp melting point. Typical results of spectrographic analysis of the Westinghouse zirconium are shown in Table 11. These data indicate a very high purity. The Bureau of Mines sponge metal was probably less pure but had good ductility. Melting: All of the alloys used in the investigation were made by melting pieces of vanadium and zirconium together in a dc electric arc furnace similar to those of Geach and Summers-Smith, craighead, Simmons, and Eastwood," and others. Melting was done in an atmosphere of helium scavenged of residual air by the preliminary melting of a separate charge of zirconium. Each ingot was turned over and melted at least three more times before removal from the furnace to aid in the attainment of homogeneity. Alloys prepared for use in the investigation are listed with the results of solidus determinations in Table III with the exception of the following compositions upon which no solidus determinations were made: 0.29, 0.54, 4.57, and 5.55 pct V. Analysis: The weight of each ingot made from iodide zirconium was within 0.1 g of the total weight of the initial charge, about 90 g. Since each component of each charge was weighed to the nearest 20 mg for amounts less than 10 g and to the nearest 0.1 g otherwise, the gross composition of an ingot could be calculated accurately. Chemical analysis for the vanadium content of several alloys agreed

Jan 1, 1956

A. V. ADAMSON,* New York, N. Y. (written discussion).-The experience of users of pulverized fuel in metallurgical work, particularly for open-hearth furnaces, has demonstrated that high ash and sulfur in pulverized fuel are a detriment, the sulfur in the coal entering into the finished product; hence, in this class of work it is extremely important, when pulverized coal is to be used, that the coal be selected with care, and only those having low percentages of sulfur be used, in combination with proper means for combustion. I have found that no general statement can be made as to the cost of pulverized coal, each installation being an individual engineering problem and necessitating a varying capital expenditure; as each installation has its own power cost, the actual cost of pulverizing varies between wide margins. It has been found that no general rule can he laid down as to either fineness or dryness; for some uses a wide range is permissible in both factors, while some classes of fuel require different treatment from others. Anthracite, coke breeze, and lignite ash will, under certain conditions, form slag, the melting point of the ash from fuel of this character being practically the same as of that from bituminous coal; furnace temperatures above the melting point of ash must therefore cause the formation of slag. However, it should he noted that furnace temperatures attainable with this class of fuel are not usually so high as those from bituminous coal, which probably explains the statement that the former do not slag. In a well designed furnace, temperatures above 2250° F. (1235° C.) will be obtained with that class of fuel, and slags will be formed. Too much attention apparently has been centered on high CO2 contents of stack gases. A high percentage of C02 is frequently obtained at the expense of the brickwork, the furnace temperature being increased by diminishing the excess air; a high percentage of C02 thus simply means a small proportion of 02.

Jan 12, 1918

By John McDonald

THE amount of published literature in the field of mechanical proper-ties of magnesium alloys is not great; particularly with respect to rolled alloys. Haughton and Prytherch1 have summarized most of the articles to 1937, including their own work on sheet. Although many papers can be found dealing' with the technology of magnesium and the alloys now in commercial use, there does not seem to be any work dealing exclusively with the variation in properties of rolled alloys as caused by changes in alloy composition. Comparison of published data reveals considerable discrepancies in, properties of alloys of the same composition, probably due to differences in the details of working and heat-treating followed by different workers. The purpose of this paper is to study the proper-ties of alloys in conditions where the effect of such differences have been eliminated. It is well known that the strength and ductility of metals are functions of the working and heat-treating they have received, as well as of their chemical composition. In comparing alloys with respect to these proper-ties, therefore, all possible combinations of the variables of the fabrication procedure ought to be carried out on each alloy. One or more of these treatments will produce the highest ductility, or strength, or both. These highest properties would then be selected as characteristic of each alloy, and alloys would be compared on the basis of those properties. Thus a separation of the effect of composition and that of working and heat-treating would be achieved. In this paper, however, a compromise with completeness has been made by carrying out a restricted number of treat-ments. As a consequence, the properties obtained are not necessarily the best that the alloy is capable of exhibiting; but since all alloys have been treated by the same method, the results ought to be comparable. The elements selected for the study comprise a class that will alloy easily with magnesium, and that are relatively cheap. Each was added in different amounts, up to a limit that varied with the element.

Jan 1, 1939