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By H. M. Morse

Mississippi, during the year 1941, experienced the greatest diversity of oil activity since the beginning of oil interest in the state—core tests for exploration, core tests for sulphur, continued drilling at Tinsley for production, and wildcatting, which brought to light two new oil fields and two new salt domes. There were 45 wildcat wells drilled in 1941, which showed greater results and findings geologically than the 85 drilled in 1940. Tinsley Oil Field (Yazoo County).—The Tinsley oil field, with its boundaries fairly well defined now, is 8 miles long and 3 miles wide at its widest point. During the past year 213 producing wells were completed, which brought the total number of producers in the field by the end of 1941 to 325 wells. Seven producing sands have been logged, with a total average thickness of 30 ft. of oil sand. The producing formations are the Selma, Eutaw and Tuscaloosa. The average total depth of the wells is 5012 ft. The average gravity of the oil is 35.4°. Production for 1941 was approximately 15,500,000 bbl. of oil. Vaughan-Pickens Oil Field (Yazoo County).—At the end of 1941 only three wells were Producing in this field, the fourth having been abandoned. The total production for the field for the year was approximately 250,000 bbl. of oil. The producing sand is the Wilburn, in the Eutaw formation. Cary Field (Sharkey County).—The British American Oil Producing Co. completed, on Sept. I, 1941, its F. B. Houston No. A-I well, sec. 23, T. 11 N., R. 7 W. It is

Jan 1, 1942

By H. M. Morse

Mississippi, during the year 1941, experienced the greatest diversity of oil activity since the beginning of oil interest in the state—core tests for exploration, core tests for sulphur, continued drilling at Tinsley for production, and wildcatting, which brought to light two new oil fields and two new salt domes. There were 45 wildcat wells drilled in 1941, which showed greater results and findings geologically than the 85 drilled in 1940. Tinsley Oil Field (Yazoo County).—The Tinsley oil field, with its boundaries fairly well defined now, is 8 miles long and 3 miles wide at its widest point. During the past year 213 producing wells were completed, which brought the total number of producers in the field by the end of 1941 to 325 wells. Seven producing sands have been logged, with a total average thickness of 30 ft. of oil sand. The producing formations are the Selma, Eutaw and Tuscaloosa. The average total depth of the wells is 5012 ft. The average gravity of the oil is 35.4°. Production for 1941 was approximately 15,500,000 bbl. of oil. Vaughan-Pickens Oil Field (Yazoo County).—At the end of 1941 only three wells were Producing in this field, the fourth having been abandoned. The total production for the field for the year was approximately 250,000 bbl. of oil. The producing sand is the Wilburn, in the Eutaw formation. Cary Field (Sharkey County).—The British American Oil Producing Co. completed, on Sept. I, 1941, its F. B. Houston No. A-I well, sec. 23, T. 11 N., R. 7 W. It is

Jan 1, 1942

By G. Baralis, P. Gondi, I. Tangerini, G. Scandola

The precipitation behavior of Zn-0.5 pct A1 alloy single crystals was studied by means of electrical resistivity measurements and by optical and electron microscopy. The single crystals for the resistivity measurements were prepared by an original method in - 100-p -thick sheets. The order of the precipitation kinetics ranged between 1 and 1.5. The dislocations play a relevant role in the first-order kinetics. Precipitation always occurs both on dispersed particles and on dislocations. Statistical examinations have shown that the first-order kinetics can have two different activation energies; i.e., the precipitation can have dz;fferent mechanisnrs which could not be identified, however, in the course of the research. During the tnetallographic exanzination of the precipitation structures a specific process of dislocation decoration was obsereed. The main purpose of this work was to study the contribution of dislocations to the precipitation. A number of authors have observed precipitation on dislocations and reference might be made to several monographs on the ubject.'' The possibility that dislocations also accelerate precipitation has been considered by Turn-bull3 and Fischer et al.4 The studies described in the present paper were carried out on zinc, chosen as a base metal owing to the ease with which dislocations can be introduced into it and because of the absence of excess vacancies after quenching in conditions where phenomena of accelerated precipitation still occur. Aluminum was preferred as alloying element because of the accelerated precipitation phenomena that resulted in a preliminary reearch. EXPERIMENTAL METHODS The observations refer to a Zn-0.5 pct A1 alloy. The zinc was 99.995 pct pure; a typical spectroscopical analysis is given in Table I. As a rule the alloy was subjected to homogenization, quenching, or slow cooling and annealing. Homogenization was carried out by heating at 390" to 410°C for 24 hr. From the homogenization temperature, some specimens were quenched and some slowly cooled at a rate of 2°C per sec. At this rate no precipitate was detectable under the optical microscope just after cooling. Quenching was carried out simply by dropping the specimens into water, aqueous ethylene glycol solution at -30" c, or liquid-nitrogen baths placed close to the homogenization oven. Vaseline oil baths were used with a thermal stabilization of 10-20 for both the aging treatments and the measurements; aging was generally carried out at 90" or 130°C. To avoid oxidation phenomena during heating, the vaseline oil baths had to be frequently renewed. The precipitation kinetics were studied by means of electrical resistivity measurements, using ans potentiometric method (reproducibility ± 5 x 10 5 v, that is 0.5 pct of the total voltage decreases on the specimens during precipitation). First, various types of specimens were tested, i.e., polycrystals, single crystals grown in capillary quartz tubes, and thin single-crystal sheets prepared by means of an original method requiring no container except for the natural oxide. Even if fully annealed, the polycrystals and the capillary grown single crystals showed resistivity in -creases, most probably due to dislocations introduced in the course of the measurements. Similar resistivity increases in pure zinc were noticed by another author. Only the single-crystal sheets showed no resistivity change; thus they were chosen for the subsequent tests. As already mentioned, these single crystals were obtained by using, as a container, the natural oxide on the zinc surface; the oxide strength is sufficient to maintain the original shape during melting with sheets up to 500 p thick. An initial zone melting and subsequent zone leveling, which led also to formation of the single crystals, were thus carried out on rolled sheets of the required thicknesses (- 100 p) and shape, lying on a flat silica surface. The resistivities were first evaluated by measurements at the liquid-nitrogen temperature. This method gave poor reproducibility, however, and this was attributed to the thermal cycles which had to be operated. To avoid cycles and handling, it was therefore decided to make measurements directly in the annealing oil baths; this required thermal stabilization at ilo-' "C. In this way only the resistance changes were measured. Specimens of pure zinc and of completely annealed alloy were always examined as controls together with those under consideration; only those measurement runs were taken into account where the reference samples showed no resistance increases. Again, the main inconvenience was due to oxidation and this was avoided by renewing the oil baths; even so data reproducibility was poor and the observations were therefore carried out on a large number (many hundreds) of specimens so as to provide indications of statistical value. For the transmission observations under the elec-

Jan 1, 1969

An abstract of a paper from the Canadian Mining and Metallurgical Bulletin of August 1978 by E. Stamboliadis, J. McHardy, T. M. Salman, Department of Mining and Metallurgical Engineering, McGill University, Montreal, Quebec, states that: “The recovery of gold, silver and other heavy metal cyanides from mill solutions is technically possible using the ion exchange technique. However, the costs involved are greater than the costs of the zinc precipitation technique used for gold recovery. There are two main reasons for this: one, the fact that in gold ore cyanidation metal cyanides other than gold and silver occupy most of the resin capacity and hence reduce the adsorption efficiency of the resin for the Au and Ag cyanides; secondly, the high cost of the eluting agents.” Resin, therefore, cannot in most cases be efficiently used for recovery of precious metals. With copper in solution, only 1.47% of the resin capacity is used for gold and 0. 8970 for silver; the rest is occupied by unwanted metal cyanides, such as copper occupying 73.7%. On the other hand, although activated carbon will adsorb copper cyanides, they will be preferentially displaced by gold and silver cyanides. Ion exchange is by one or two orders of magnitude more expensive than the conventional method of zinc precipitation. The cost of removing impurities, such as copper from the resin, is greater than the cost of recovering gold. With an oxide ore amenable to cyanidation and with a low content of other metals, such as may occur with some of the Soviet gold deposits, ion exchange would be an efficient as Carbon-In-Pulp.

Jan 1, 1981

By J. D. Price, W. M. Bertholf

One of the chief difficulties with which the operator of a coal washing plant has been forced to contend is the handling of the very fine coal. First he has the problem of separating the fine coal from washery water. This is usually accomplished by the use of settling cones or Dorr thickeners: in either event the separated fine coal contains a high amount (40 to 80 pct) of water and, somewhat loosely, dependent upon the size of the coal particles present, may be known as sludge or slurry. His second problem is the satisfactory further dewatering of such separated sludge and/or slurry.

Jan 1, 1949

By J. A. Ede

The property of the Spring Valley Coal Company, situated in Bureau county, Ill., comprises something more than 30,000 acres of coal-lands, on which have been opened four mines, designated as Nos. 1, 2, 3 and 4. Figs. 1, 2, 3 and 4 are plans of the first three; and Fig. 7 is a view of the surface-plant at No. 4, the workings of which it is not necessary to illustrate, as this mine has been practically merged in No. 2. No. 4 shaft is only 500 feet from No. 2, and both are ventilated by the same fan, and are in the same circle of air-supply. In speaking of No. 2, we now include No. 4. The system pursued in all the mines is " long-wall advancing," and the shafts are all vertical. The seam worked is locally and commercially known, in the Illinois series, as No. 3; but its position in the geological series is that of No. 2. It averages in thickness about 42 inches, arid has no partings, but mines in rectangular lumps, which stand a large amount of handling before breaking. An analysis made from Colliery No. 1 gave the following : Per cent. Moisture,.......... 1.45 Volatile combustible matter,.47.27 Fixed carbon,.........41.97 Sulphur,.........2.46 Ash,....... .. .. .. 6.85 Plate 6 shows a photographic view of this seam. The staff seen in the view is 37 inches long. The table on page 188, recorded in my office, which I presume to be correct, may be of interest. The bottom is fire-clay, varying in thickness from 6 to 24 inches. It affords what is considered good mining-ground. The roof immediately above the coal is a dark shale, lying in small bands, from 4 to 9 inches in thickness. Between the

Jan 1, 1900

By C. A. Rowland, R. C. Nealey

Until recently there were very few dry grinding rod mills used. The early installations performed as anticipated. In the last seven years a number of dry grinding rod mills have been made, most of which have been used for grinding iron ore. The recent installations have not operated as anticipated in accordance with practices learned from wet rod milling. The paper does not establish any definite rules for the application of dry grinding rod mills but does attempt to establish some guidelines that can be followed. The paper reviews a number of flowsheets describing the problems encountered and some of the solutions found. Completely dried compared to partially dried feed is reviewed. Problems encountered in scaling up from pilot plant to production-size mills are described. Rod sizing, effect of rod length, rod bending, rod breakage, and rod tangling are discussed. While wet grinding rod mills have been used for 50 years to grind ores and make specifications sands, dry grinding rod mills have only recently come into significant use in the mineral industries. Among the materials now being processed in dry grinding rod mills are (1) lead sinter, lead slag, and limestone; (2) iron ore; (3) silica; (4) cement clinker; and (5) coke. Because the application of wet grinding rod mills was well understood at the time that dry grinding rod mills were introduced, the criteria and guidelines for selecting the former were carried over to the selection of the latter - in some cases with the anticipated results, but in many cases not. It is the purpose of this paper to describe, through a series of flowsheets, some of the recent problems encountered with dry grinding rod mills, to point out the solutions to these problems, and to set forth some guidelines for the selection and application of these mills. When dry grinding rod mills came into use, the following facts about their wet grinding counterparts were already well established: (1) The performance of large-sized mills can be accurately predicted from the performance of rod mills 5 or 6 ft in diameter. Wet grinding mills as large as 14 ft in diameter (inside shell) by 20 ft long with rods 19.5 ft long can operate satisfactorily.

Jan 1, 1970

By A. W. Cochardt

THERE are a number of effects that can cause material damping or internal friction. Some of these are frequency dependent, such as the thermo-elastic effect' and the stress-induced ordering.' Others depend on the amplitude of vibration, i.e., the damping related to the motion of dislocations3 and that due to magneto-mechanical hysteresis.' While many of these effects have been studied, only the magneto-mechanical effect has found extensive practical application. It is the principal source of damping in the current blade material in steam turbines.A magneto-mechanical hysteresis loop is seen in Fig. 1. If an unmagnetized, polycrystalline wire of a material exhibiting magneto-mechanical hysteresis, such as an Fe-14 pct A1 alloy, is twisted in torsion, a relation between shear stress and shear strain y is observed as indicated. The stress-strain curve does not follow Hooke's law -dashed line. Instead, the strain y increases nonlinearly and partly irreversibly, due to the motion of ferromagnetic domain walls,* until a critical stress is reached, which in this case is about 3,500 psi. If the applied stress is raised further, the strain appears to increase linearly and reversibly in accordance with Hooke's law, since all domains are now aligned in easy directions of magnetization nearest to the direction of the applied stress, and plastic flow has not yet started noticeably. On removing the applied stress, a remanent shear strain y, is observed, which is related to the irreversible magnetostriction of the material.' The energy dissipated in the material during a stress-strain cycle is proportional to the critical stress t, and the remanent magnetostrictive shear strain 7,. The purpose of this investigation was to make a survey of the magneto-mechanical damping of ferro-

Jan 1, 1957

By J. A. B. Forster

The operations of the Electrolytic Zinc Co. of Australasia Ltd. involve the preliminary roasting of zinc concentrate from Broken Hill, New South wales, at a number of acid-making centers on the Australian mainland. The partially roasted material is shipped to the Tasmanian plant where it was formerly re-roasted prior to leaching,' but this practice was gradually abandoned in favor of the flotation of leach residue for the recovery of a concentrate containing about 22 pct sulphide sulphur and known as secontlary or Risdon concentrate.2 This change, together with increased zinc production, called for new furnaces at Risdon for the roasting of 10-50 tonst of secondary concentrcite and 90 tons of new concentrate per day. The war situation made it imperative that construction be commenced without delay and to save time it was decided to base the design on that of Skinner type furnaces which had been built in South Australia twenty years earlier. This involved some sacrifice of desirable features but did not prevent the incorporation of provisions which had enabled small Herreshoff type furnaces to roast secondary concentrate autogenously. The roasting rate in existing furnaces was 10-12 Ib sulphide sulphur per sq ft of hearth area per day, and eleven hearths, 20 ft in diam, were provided in the two new furnaces in anticipation that they would prove capable of the autogenous roasting of 130-140 tons of concentrate per day from 28-29 pct sulphur down to 4.5-5 pct, with an oxidation rate of 11-11.5 lh S/S per sq ft of hearth area per day. It was soon realized, when the first of the furnaces went into operation, that a much better performance than this might be given, and the purpose of this paper is to show how a treatment rate of 100 tons per furnace day, and oxidation rates approaching 15 lb S/S per sq ft per day have been reached. Furnace Design General specifications for the design were based on the results of experience with several other types of furnace and on the special operating conditions

Jan 1, 1950

By W. M. Courtis

. There seems to be a well-established belief that there is an indescribable something in the appearance of gold-quartz not to be learned from books, that enables those who are fortunate enough to have acquired the power to recognize this characteristic, to pronounce at once that a certain quartz will or will not pay. The stronger this claim is made, the more certain is the claimant to be one of the self-styled practical miners. After several years spent among the gold-mines of California with practical and professional gold-miners, I have come to the conclusion that very few care to risk an opinion on a piece of quartz until some of it has been "horned out." Nevertheless, there is what the miners call a " kindly " appearance, that is more often followed by good results than is a vitreous, water-wet-looking quartz. A dark, resinous quartz seems to be most in favor, but there are so many exceptions that even quartz as " white as a hound's tooth " produces gold in some mines.. The ribbon-quartz, a laminated variety, separated by thin talc or chlorite partings, has a well-known good name. The slides of rich quartz specimens show that this parallelism is a microscopical characteristic of the only macroscopical distinction that, as a rule, these quartzes show. This is shown by Nos. 12 and 13, photographs of the richest quartz, that averaged $65 per pound. It is noticeable, also, in Nos. 7 and 9, and others. Dr. Hensoldt, of Columbia College, who prepared, excellently, a large number of my slides, and whom I have to thank for descriptions and suggestions, says of Nos. 12 and 13: "This variety of quartz differs considerably, microscopically, from the others of your locality, and is, in more than one respect, remarkable. Like the

Jan 1, 1890

By Robert W. Thomas

LEACHING of mined-out areas at the Arizona property of the Ray Mines Division, Kennecott Copper Corp., was started on Jan. 20, 1.937, and by July 1, 1938, 10,000,000 lb. of copper had been produced by this method. Leaching operations at present are confined to the western portion of the ore body and over an area of approximately ten acres. The ore in this area was extremely high in pyrite and the copper content, which averaged slightly in excess of 1 per cent, was the result of incomplete secondary enrichment by solutions which apparently worked laterally from the main ore body. Above the ore was an unaltered zone of primary or protore averaging 125 ft. in thickness and containing approximately 0.6 per cent copper. Above this was the capping or leached zone averaging 50 ft. thick.

Jan 1, 1938

By Nev A. Gokcen

PUBLISHED data on the solubility of nitrogen in liquid manganese are widely discordant. Ochsenfeldl observed that a Mn-N alloy with 3.6 pct N consisted of solid and liquid phases at 1260°C but at 13 00° to 1340°C the solid phase disappeared and the liquid contained 0.1 to 0.13 pct N. In contrast Saito's measurements at approxhately 1400°C yielded an average value of 0.97 pct N. Sieverts3 volumetric method is not suitable for the determination of gas solubility in manganese because the liquid metal vaporizes readily and condenses in the cooler parts of the apparatus where it can absorb large amounts of nitrogen. The purpose of this investigation was, therefore, to determine the solubility of nitrogen in manganese accurately in the range of 1273" to 1500°C. The experimental method used in this study was as follows. Electrolytic manganese of 99.9 pct purity, and weighing 50 g, was melted in a pure alumina crucible placed in a tubular furnace. Temperature was measured with a Pt-10 pct Rh thermocouple and controlled within ± 5°C. Pure nitrogen was bubbled through the melt for 1 hr at constant temperature and then a sample was taken by sucking the metal into a 2-mm clear silica tube and immediately quenching in water. The sample was broken into small pieces and found to be sound to the naked eye. The entire sample was then dissolved and the resulting solution was analyzed for nitrogen by the well-known solution-distillation method. The experimental results are presented in Fig. 1. All the nitrogen solubility data refer to 1 atm of nitrogen pressure; hence the observed values are slightly corrected by using Sieverts' equation when the atmospheric pressure differed more than 5 mm Hg from 760 mm, and further, in the case of the runs at 1500°C the correction arising from the presence of Mn vapor has been made. (Cf. Eq. [3]). Scattering in the data is within ±5°C in temperature measurement and ±3 pct in total nitrogen analysis. The straight line in Fig. 1, correlating the percentage of dissolved nitrogen, %N, with the inverse temperature in OK-1, can be expressed by:

Jan 1, 1962

By K. A. Slagle, D. K. Smith

weight obtained. Additives used in conjunction with salt in these slurries have included silica flour, calcium ligno-sulfonate and cellulose retarders, granular lost-circulation materials, bentonite and selected low-water-loss additives that are not significantly deteriorated by the presence of the chloride ion. In some other areas of South Texas, the salt-saturated slurries have been used quite extensively for improvement of the flow properties of slurries and attainment of better circulation characteristics at lower displacement rates. Concurrently with this property, the protection of shales and shaly sands is also realized, as well as useful retardation of the slurry. Resultant superior cementing jobs have been indicated by both communication tests and acoustic logs for bonding to pipe and formation.' In one section of Louisiana, a major oil company has been using salt-saturated API Class A cement with calcium lignosulfonate retarder for cementing through the Miocene at 9,000 to 10,000 ft. This is another of the situations where interbedding of sands and shales exists, creating difficulty in maintaining formation competency when a fresh-water slurry contacts the clay minerals of the formation. Further work has also been done in the shaly Miocene formation at 13,000 to 15,000 ft where fairly close water or gas contacts are encountered. Indications thus far are that better segregation of these various fluids is obtained by use of the saturated salt slurries because of their improved formation bonding characteristics. In addition to the properties of salt in this situation, attainment of turbulent flow at minimum displacement rates has also been accomplished by use of an additive to help provide exceptional dispersion and viscosity reduction of the slurry. Another oil company was encountering considerable expense in completing wells in Southwestern Louisiana due to extensive block squeeze requirements for effective separation of zones. A very effective mud program was being used to minimize washout in the shale sections and, apparently, a nearly gauge-size hole was being obtained. However, primary cementing results with fresh-water slurries were generally poor. On a few occasions when slurry was actually circulated to the surface, large pieces of shale formation were brought out of the hole with the slurry, indicating a severely water-sensitive, sloughing formation. Inhibition of shale heaving was being accomvlished in the drilling program, and immediately indone ipon circulation of the fresh-water slurry even though it contained a low-fluid-loss additive to reduce filtrate damage in the sands. The subsequent change to salt-saturated slurry yielded 11 successful primary cement jobs out of 12, compared to the previous success ratio of practically zero. Since these were deep, high-temperature wells in the range of 13,000 ft with high-pressure zones necessitating 17.5-lb/gal fluid densities, the slurry used was API Class E cement, silica flour, weight material, retarder, salt saturation (which also reduced the amount of weight material) and maintenance of low fluid loss by use of a salt-compatible additive. Other salt slurries have been used to a limited extent in this same general area for similar problems at depths ranging from 5,000 to 17,000 ft. In the shallower wells, the cement has usually been API Class A where the salt functions as a retarder, and in the deeper wells API Class E cement is used with the additional salt advantage being its increased slurry weight and inability to dissolve salt stringers. A considerable number of squeeze jobs have also been done on older wells using the salt-saturated slurries with very good results. MID-CONTINENT In North Texas, salt-water slurries have been used for cementing the Woodbine sand, Strawn sand, KMA sand and Pettit lime. Shales surrounding these formations have created the same difficulty in obtaining separation of producing zones that has been the problem in other areas. Depths in this area range from 3,400 ft for the Strawn to 7,400 ft for the Woodbine, and concentration of salt has varied accordingly. In the deeper wells, where retardation is desired, saturated salt-water cement is used; for the shallower wells, in order to provide shorter waiting-on-cement times, the amount of salt has been 18 per cent by weight of the mixing water. Results have been excellent with no reported failures on any of the salt cement jobs; where acoustic bond logs have indicated indifferent bonds previously, they are indicating very good bonding for the salt slurries. In Oklahoma various shales of Pennsylvanian age exhibit a high degree of sloughing in the presence of fresh water, causing severe washouts above and below sand formations which it is desired to isolate. This situation exists to some degree in practically all parts of Oklahoma and includes formations of other ages such as the Wood-ford shale. For the past few years, salt-saturated cements and displacement rates as high as practical have been used as a remedy for this problem, with very good results. The Layton and Bartlesville formations are two examples of shaly sands where saturated slurries have been helpful. In one area where five wells were drilled through this type of problem shale without obtaining a satisfactory primary cement job, a change was made to salt-saturated cement preceded by a suitable chemical wash for the drilling mud involved. Acoustic bond logging indicated excellent bonding, and final completion bore out this result by being trouble-free. This type of slurry has also been used extensively on squeeze jobs where shales have been heaving around the producing formations. Predominantly, the basic slurry has been either API Class A cement or a pozzolan cement—although, as deeper wells are being drilled, the use of salt in Class E cement is also increasing. Salt cement in West Texas has been used primarily to help prevent channeling through the shales around the Delaware sand, Queens dolomite and Hope lime. Many of the shaly and dirty sands of this area are sensitive to the filtrate from a fresh-water cement. Salt at 16 to 18 per cent by weight of mixing water has been added to centent, and has been effective in controlling formation damage and communication between zones in these formations. Use of these lower salt concentrations is dictated in this area by the relatively low formation temperatures where retardation of the slurry would create unduly long waiting-on-cement times. Also, quite a bit of cementing has been done in this area using salt concentrations in the accelerating range— that is, 2 to 5 per cent by weight of water. Specifically, these concentrations have been used in coiljunction with high percentages of gel to overcome the retarding effect of the calcium lignosulfonate dispersant, although there are probably several shales where these concentrations could provide some degree of formation stability. On several occasions, the salt has also been used to lower the critical velocity or rate for turbulence with the slurry, particularly in the pozzolan cements. On wells in the Hope lime, it has usually been necessary to squeeze the shale above and below the lime to get a water-free completion. Use of salt-saturated slurries has largely eliminated this

The papers discussed in the following pages were presented during two sessions of the Geophysics Education Committee of the Mineral Industry Education Division on Feb. 17 and 18, 1941. At the first meeting, to consider the "Influence of Geophysics upon Geology Curricula," this Committee was joined by the Geophysics and Mining Geology Committees of the A.I.M.E., the Society of Economic Geologists, representatives of the American Geophysical Union, and delegates from the Committees on College Curricula and on Applications of Geology of the American Association of Petroleum Geologists. Quentin D. Singewald and Sherwin F. Kelly presided. At the ensuing session, especially emphasizing the integration of geology, physics and chemistry for the solution of earth problems, the joint participants with the Geophysics Education Committee were the Geophysics Committee, and representatives of the American Geophysical Union and of the Committee on College Curricula of the American Association of Petroleum Geologists. Richard M. Field and W. R. Chedsey presided. In the following summary of the discussion at the two meetings, written discussion submitted subsequently is not differentiated from that offered orally at the session. A provisional report of the Geophysics Education Committee was presented at the second session, and some of the following discussion refers to it. This report has not been printed (it is anticipated that a more comprehensive, final one will be rendered at the 1942 annual meeting). A few mimeographed copies of this provisional report were made. Dr. W. P. Haynes presented some notes prepared by Dr. F. H. Lahee, Chairman of the American Association of Petroleum Geologists' Committee on College Curricula. This Com- mittee's inquiries reveal the general opinion that a four-year academic preparation is inadequate, five or six being advisable. The fundamentals, mathematics, physics, chemistry, and English composition, should be stressed in the first three years, with specialization in the last two or three years. Some companies provide an apprenticeship period, and themselves give additional training. During academic years more attention needs to be given to engineering training, to field mapping, and in geology to stratigraphy and sedimentation. The amount of mere memory work should be cut, and men trained to observe and reason. Dr. Lahee emphasized the need of more adequate preparation in English composition, because of the inability of many graduates to compose acceptable reports. Sherwin F. Kelly pointed out that much time in university training, which ought to be devoted to technical subjects, was taken .up with English courses. He emphasized that it is the part of the universities to demand of the high schools that the students they send to the university be properly trained to speak and write English. Prof. W. T. Thom protested against the crowding of high-school material into already overcrowded college curricula. C. E. Dobbin, chairman of the Committee on Applications of Geology of the American Association of Petroleum Geologists, described briefly the work of his committee in publicizing geology, and said that it found a widespread popular interest in the subject but a lack of appreciation of its importance. He recommended that attempts to coordinate the works of geologists and geophysicists be expanded somewhat toward the further developing and encouraging of a "species of geopolitician" capable of assisting the progress of geology and geophysics by more vigorous advertising of

Jan 1, 1946

The papers discussed in the following pages were presented during two sessions of the Geophysics Education Committee of the Mineral Industry Education Division on Feb. 17 and 18, 1941. At the first meeting, to consider the "Influence of Geophysics upon Geology Curricula," this Committee was joined by the Geophysics and Mining Geology Committees of the A.I.M.E., the Society of Economic Geologists, representatives of the American Geophysical Union, and delegates from the Committees on College Curricula and on Applications of Geology of the American Association of Petroleum Geologists. Quentin D. Singewald and Sherwin F. Kelly presided. At the ensuing session, especially emphasizing the integration of geology, physics and chemistry for the solution of earth problems, the joint participants with the Geophysics Education Committee were the Geophysics Committee, and representatives of the American Geophysical Union and of the Committee on College Curricula of the American Association of Petroleum Geologists. Richard M. Field and W. R. Chedsey presided. In the following summary of the discussion at the two meetings, written discussion submitted subsequently is not differentiated from that offered orally at the session. A provisional report of the Geophysics Education Committee was presented at the second session, and some of the following discussion refers to it. This report has not been printed (it is anticipated that a more comprehensive, final one will be rendered at the 1942 annual meeting). A few mimeographed copies of this provisional report were made. Dr. W. P. Haynes presented some notes prepared by Dr. F. H. Lahee, Chairman of the American Association of Petroleum Geologists' Committee on College Curricula. This Com- mittee's inquiries reveal the general opinion that a four-year academic preparation is inadequate, five or six being advisable. The fundamentals, mathematics, physics, chemistry, and English composition, should be stressed in the first three years, with specialization in the last two or three years. Some companies provide an apprenticeship period, and themselves give additional training. During academic years more attention needs to be given to engineering training, to field mapping, and in geology to stratigraphy and sedimentation. The amount of mere memory work should be cut, and men trained to observe and reason. Dr. Lahee emphasized the need of more adequate preparation in English composition, because of the inability of many graduates to compose acceptable reports. Sherwin F. Kelly pointed out that much time in university training, which ought to be devoted to technical subjects, was taken .up with English courses. He emphasized that it is the part of the universities to demand of the high schools that the students they send to the university be properly trained to speak and write English. Prof. W. T. Thom protested against the crowding of high-school material into already overcrowded college curricula. C. E. Dobbin, chairman of the Committee on Applications of Geology of the American Association of Petroleum Geologists, described briefly the work of his committee in publicizing geology, and said that it found a widespread popular interest in the subject but a lack of appreciation of its importance. He recommended that attempts to coordinate the works of geologists and geophysicists be expanded somewhat toward the further developing and encouraging of a "species of geopolitician" capable of assisting the progress of geology and geophysics by more vigorous advertising of

Jan 1, 1946

By B. B. Betty

H. L. Burghoff.*—Have the authors any information on the effect of grain size in these materials? There is a material difference in the grain sizes shown for the Monel and the Inconel. Is a wide range of grain size normally found for each material, and, if so, what is its effect upon creep strength? 11. L. Eiselstein.—The grain size for Monel shown in the micrograph is the usual size found in that product. The grain size of Inconel is about the same as that, too. However, we have run tests on Inconel at higher temperatures than those reported in this paper, and have found that the coarser grain size has a better creep resistance; and that the grain size that gives the best creep resistance at 1600°F. is about 0.005 in. in diameter. We have no test on Monel with varying grain size. J. J. KANTER.†-It has been known for a long time that Monel metal exhibits ductility anomalies at elevated temperatures. Even in short-time test, it can be demonstrated in the range of 900°F. that there is a distinct falling off of the ability of Mone1 metal to elongate, and in rupture tests this shortcoming is still further accentuated. Knowledge of this rupture anomaly of Monel metal may be one of the reasons for which designer's approach certain high-temperature applications with reservations. The authors of this paper have merely demonstrated that for 900°F. the alloy has an ability to elongate 1.7 per cent over a period of some 2700 hr. Before any conviction can be expected from designers that Monel metal is applicable to stress design in such range of temperature, I think it is desirable to demonstrate the capacity for the material to elongate over a longer period of time than has been done in this presentation.

Jan 1, 1945

By T. L. Johnston

MUCH has been said and written about deep mine shafts and deep drill holes as man in his search for mineral wealth digs deeper into the earth's crust. Each year some new extra depth is heralded as a record, but with unlimited possibilities of going still deeper. In contrast to "digging deep," "mining high" is limited by the height of the mountains (Mt. Everest being the maximum with its 29,000-ft. elevation) and also by the extent of human endurance. An ex- ample of what might be called near- stratosphere mining in what is probably the highest mine worked by compressed air in the world is seen in a recent project in the Andes mountains of southwestern Bolivia.

Jan 1, 1939

By E. R. Helderman, C. Y. Ang, C. C. Nealey

Beryllium-base alloys have been successfully p7.-epared by the liquid-phase sintering technique. Depending orz the composition and amount of the intended liquid please, microstructures either single -phase or duplex in feature with randomly oriented grains have been obtained. Qualitative and semi-qualitative determination of distribution of alloying elements md microsegregations in some experi)uzental alloys haue been made by electron-micro-probe analysis in conjunction with microliardness testing and standard metallography. Tensile tests reoealed that some conzpositions possess attractive elastic properties with Young's mot1uli greater than 40 X 10' psi. In powder metallurgy, liquid-phase sintering is a process or phenomenon that has proven to be of practical value. For example, the heavy metals such as tungsten-copper-nickel, high-strength heavy gyro alloys,' heavy-duty electrical contacts,' and tungsten carbide tool materials are all products of liquid-phase sintering. Mechanisms involved in liquid-phase sintering, however, are not completely understood. Questions regarding the exact roles played by rearrangement of particles, liquid/vapor surface energy, solution and precipitation, and so forth, have not been completely answered. Evidence has been cited3 that at least volume shrinkage in the densification process is diffusion-controlled. It is possible that the predominant mechanisms for the complete densification and grain growth in a liquid-phase sintered system depend primarily on the alloy systems involved, in addition to processing conditions. Despite the lack of sound understanding of the mechanisms of the process, liquid-phase sintering has been and is being used to advantage either to synthesize microstructures for their special properties or to prepare alloys which are difficult to form by fusion process. Liquid-phase sintering of beryllium alloys was first attempted by Jones and Williams.4 They first tried infiltrating beryllium with magnesium, and then succeeded in preparing the alloy by sintering Be-Mg powder compact in molten magnesium bath. This investigation resulted in the identification of some Mg-Be intermediate phases. Crossley et a1.5 also used liquid-phase sintering technique in an attempt to produce ductile beryllium alloys for structural applications. The major liquid-phase components investigated by Crossley et al. were aluminum and silver with minor additives of germanium, calcium, lanthanum, cerium, and yttrium. The lack of wetting and the bleeding out of liquid phase were the difficulties encountered during experimentation. According to Hodge,6 the two compositions investigated by Crossley, which showed some promise based on compression tests, involved large amounts (over 35 wt pct) of silver, thus making them too heavy to be of practical interest to the aerospace industry and military users. The present investigation was prompted by the search for light-weight (density less than aluminum) beryllium alloys exhibiting small anisotropy in physical properties for precision inertial navigation instrument applications. In addition to isotropy, good structural properties such as high elastic modulus or desirable combination of mechanical and physical properties are also objectives of this investigation. The technique of liquid-phase sintering was chosen for its versatility in producing either duplex or homogeneous microstructures. This report is concerned with the use of copper and aluminum, with or without silicon addition, as the intended liquid phase, and the resultant micro-structures and some physical properties of the beryllium alloys. Qualitative and semiquantitative electron-microprobe analyses of some of the alloys are presented to illustrate the usefulness of this microanalytical technique for the identification of microconstituents and their distribution. EXPERIMENTAL PROCEDURES The beryllium powder used was -200 mesh Brush Beryllium Co. QMV NP-50 grade. Typical chemical analysis of the powder is shown in Table I. Commercial high-purity copper, aluminum, and silicon powders all screened to —100 mesh were used as additions. Mixed powder compositions were ball-milled in ceramic jars for 1/2 hr to ensure thorough blending. Milled powder was loaded either in 3/4-in.-diam button die or in Metal Powder Association flat tensile specimen die and compacted under top and bottom pressure. No lubricant or organic binder was used. Sintering was carried out in a quartz tube under a vacuum of 50 to 100 µ pressure. Surface hardness and some microhardness readings were taken on sintered specimens. Sintered density was

Jan 1, 1965

By William B. Plank

ENROLMENT data given in this report of the seventh study of the schools by the Mineral Industry Education Division reveals the critical situation in the mineral engineering schools of the United States. Complete figures for the year 1942-43 show that at that time, about one year after Pearl Harbor, the enrollment of mineral engineers was 6385 or 30 per cent less than in 199441. By October 1943, however, enrollment had dropped to 2050, as reported in the Journal of Engineering Education of January 1944. This was a further reduction of 68 per cent in one year, or 77 per cent in three years. With accelerated programs in effect during the current year, with many graduations since last October, and with the military forces taking practically all the high school graduates, the present enrollment is, of course, much lower than the 2050 above given. There are no late data on the exact situation. In Canada, the same situation exists in the mineral engineering schools, only

Jan 1, 1944

By K. W. Smith, E. A. Thomas

Various grades of synthetic mullite have been developed in recent years to replace or supplement natural sources of mullite deriued from the mullite group of minerals consisting of sillimanite, kyanite, and andalusite. Raw materials and heat treating processes used in making synthetic mullite are described. Chemical and physical data are given for typical grades and crystalline structure is illustrated with micrographs. Use of synthetic mullite as a refractory material in the glass and metallurgical industries is discussed. Mullite (3A12O3.2siO2), the only stable compound formed in the alumina-silica system, is usually present to some degree in all aluminum silicate ceramic products. The formation of mullite is considered beneficial to give rigidity to the structure and is dependent upon the ratio of Al2O3 to SiO2 in the original composition, particle size, degree of mixing, firing temperature, cooling rate, and the presence of auxiliary glass-forming fluxes. Mullite may also be formed at the reaction interface of fire clay or alumina-type refractories in contact with glass or slag melts. The term synthetic mullite is commonly used today to identify a class of sintered and fused aggregates or grains in the alumina-silica system having a highly developed mullite structure but derived mainly from raw materials other than the sillimanite group of minerals. Within the past 15 years extensive research has been done to develop economical processes to form sintered synthetic mullite aggregate to replace calcined Indian kyanite in super-refractories. Severa1 brands of such mullite are now being produced in commerical quantity and finding extensive use in refractories. Based on the service results of such refractories in many applications throughout the metallurgical, ceramic, and glass industry these developments have been considered successful and suitable substitutes for Indian kyanite now appear assured. EARLY DEVELOPMENT The conversion of kyanite, sillimanite and anda-lusite minerals of the sillimanite group to mullite and their use in refractories and porcelain have been discussed quite extensively in the literature by peck,' Grieg,' Riddle and Foster,3 Bowen and Grieg,4 and others and will only be mentioned here for reference to compare properties with synthetic mullite. In 1928, curtis5 reported on the development of a high temperature gas-converter process for forming synthetic mullite. The raw materials were derived mainly from lumps of high alumina clay of the correct natural composition or blends of clays and alumina that was interground and briquetted to form a suitable charge to maintain a surface combustion firing within the converter. Curtis was, no doubt, the first to illustrate by micrographs in natural color the crystalline structure of mullite derived from kyanite and mullite derived by sintering clay and alumina mixtures at temperatures above cone 32 (3123°F) and by electric fusion. In 1937, sei16 was issued a patent covering the use of a mixture of alumina-silica minerals and alumina in the proportion to form a mullite-yielding material at temperatures in excess of 3100' F. During the period from 1930 to 1940, economic conditions were not favorable for the production of synthetic mullite mainly due to an adequate supply of good grades of Indian kyanite ore suitable for conversion to mullite. Uncertain conditions on availability of the Indian kyanite during the early stages of World War II fostered further study on the development of synthetic substitutes. In 1943, McVay and wilson7 reported on an extensive investigation of domestic substitute materials. Their work covered essentially the use of mixtures of electric furnace mullite, calcined topaz, and calcined domestic kyanite. Compositions were found that gave equivalent or better hot load strength than Indian kyanite in mullite-type brick compositions; however, the calcining of the topaz presented certain physical and chemical problems on the disposition of silicofluoride and hydrofluoric acid while the high cost of electric furnace mullite was a limiting factor. In this work it was pointed out that water-quenched fused mullite was found to be unstable on reheat and gave poor hot load strength due to excessive glass present whereas the slow cooled or annealed mullite contained large crystals of mullite and corundum with little glass and gave superior results.

Jan 1, 1961