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President MRS THORNS E LLOYD 14 Green Hill Road Morristown, N J First Vice-President MRS A B PARSONS 52 Edgewood Road Scarsdale, N Y Second Vice-President MRS H A PROSSER 1001 Park Avenue New York, N Y Third Vice-President MRS HARRY J WOLF 3 Glenwood Avenue Littleneck, N Y Fourth Vice-President MRS MARK LAWRENCE REQUA 140 North Plymouth Blvd Los Angeles, Calif Fifth Vice-President MRS NEWELL G ALFORD 314 South Homewood Avenue Pittsburgh, Pa

Jan 1, 1952

By David W. Kennedy, Stephen P. Harrison

In the past few years, a new system has been developed for ventilating longwall panels in some gassy coal mines in the Northern West Virginia area. This system utilizes a five or six foot diameter air shaft to ventilate a group of three or more longwall panels dependent on conditions. This shaft exhausts all the air needed to, ventilate the active longwall and adjacent gob areas. By law, this bleeder fan can handle double the maximum methane concentration allowed in a normal return air course. As a result, the methane that must be diluted by the primary ventilation circuits is reduced. This new ventilation system was first conceived by mine management as a means of coping with a sudden shift in production mode that occurred a few years ago. Formerly, production often consisted of room and pillar mining with continuous miners. The high methane liberation rate was handled by driving entries around a large block of coal prior to mining. This isolated the future mining area from the adjacent coal seam and allowed a major portion of the trapped in situ methane to bleed off. Also, these bleeders served to exhaust return air from the mining area. Once the bleeders were established, productive mining could start. When the decision was made to shift production mode from continuous miners to longwall mining, some of the bleeders did not encompass large enough unmined areas under the old ventilation system to initiate longwall production. Also, many other established continuous miner section bleeders were either improperly positioned or too restricted for longwall ventilation. Unfortunately, standard bleeder development can take up to two years' time. In order to eliminate the old style bleeder system and maintain or increase the margin of safety for ventilation, the bleeder shaft system was conceived. With this system, the only entries developed are those necessary for the longwall, significantly reducing the production delay. In this area, the Pittsburgh #8 coal seam dips to the northwest. As a result of this dip, the bleeder shaft is constructed in the northernmost set of tailgate entries. In this manner, groundwater accumulations can be pumped to the surface and bleeder entries kept dry. During the initial longwall entry development, the bleeder fan can be used to ventilate entries adjacent to virgin coal where significant methane liberation often occurs. Once longwall production starts, the bleeder shaft exhausts the entire air quantity necessary to safely ventilate the longwall. As the bleeder entries deteriorate, the air quantity and pressure characteristics must be increased. The extreme flexibility of the centrifugal fan used at the surface allows the air quantity and pressure to be adjusted without stopping the fan. This improves safety by decreasing the possibility of a methane buildup resulting from the fan being out of service. The bleeder shaft system of ventilation, developed by mine management in Northern West Virginia, can provide a safe means for effectively ventilating longwall panels in excessively gassy mines. This system should be considered where mining conditions are comparable.

Jan 1, 1982

By R. G. Jones, W. L. Kinney, R. E. Schilson, R. S. Wilson, G. A. Clark, H. Suralo

This paper describes the field opeturluns at the Fry in situ combustion project in Crawford County, 111. Field operations may be divided into three phases—-preliminary engineering studies of 1960 and 1961, ignition, and, finally, operation of the test. The Fry combustion project was a pilot test of cocur-rent in situ combustion on a 3.3-acre inverted five-spot. In the summer of 1960, air injection tests were conducted using old wells in the area and a new air injection well drilled especially for the test. In the summer of 1961, four new oil wells were drilled on a 3.3-acre pattern for the pilot test. All old wells in the near vicinity of the pilot test were abandoned to preclude any possibility of gas escaping to adjacent formations. A compressor plant was also installed at the test site in 1961. Air injection tests and other engineering studies were made. At the conclusion of these tests, ignition was accomplished with a 40 kw electrical igniter. Operation of the Fry combustion test was little different from the usual oilfield operation with the exception of the high rate of air injection. No difficulty was found with the openhole completion. There were no unusual corrosion or emulsion problems until bottom-hole temperatures exceeded 150F. Four cores were drilled into the burned-out portion of the reservoir with no mechanical difficulties. INTRODUCTION A cocurrent or conventional in situ combustion test was conducted on the Fry unit of the Marathon Oil Co., in Crawford County, Ill. Besides testing combustion in the Fry type of reservoir, the test was intended to evaluate various operating procedures. This paper presents a discussion of the Fry combustion test field operations. The geology of the reservoir and the test performance are discussed in other papers.'.' HISTORY OF THE FRY UNIT The Fry unit consists of 11 leases totaling 337 acres in an area in which oil was originally discovered in 1906. Production from this reservoir, as from all Robinson sand reservoirs in the area, was very high during the first few years. As the dissolved-gas energy was dissipated, early attempts to retard the decline consisted of vacuum, air, and gas repressuring, and recently, most of the area has been subjected to water flooding. Following early air repressuring, the Fry waterflood unit was formed and water flooding initiated in July, 1952. In the area in which the Fry combustion test was conducted, a peripheral water flood of a 160-acre area was developed as shown in Fig. 1. Between 1956 and 1960, it became apparent that the water flood was unsuccessfd. In looking for a suitable site for an in situ combustion test, the Marathon Oil Co. selected the Fry unit as possessing those features most desirable for such a research project. Field operations associated with the Fry combustion test began in the spring of 1960.

Jan 1, 1966

By Charles M. Packer, Oleg D. Sherby, Roy H. Johnson

Originally round tensile specimens of a eutectic Zn-A1 alloy develop elliptical cross sections during superplastic deformation. This observation, coupled with a detailed study of the microstructure and preferred orieniation, suggests that crystallographic slip and continuous grain boundary migration or re-crystallization are important processes during super-plastic deformation. In spite of the extensive activity in superplasticity1-15 and the numerous explanations proposed, no single model has had universal acceptance. It has been established, however, that the general requirements for superplastic extension of two-phase alloys include an extremely fine, stabilized grain size of the order of a few microns, a temperature about equal to or greater than one-half the melting point, a critical range of strain rate, and a similarity in the mechanical strength of the major phases. The proposed models can perhaps best be characterized in terms of the important phenomena associated with them. These phenomena include: phase instability,1 diffusional creep by volume diffusion3 or grain boundary diffusion4,5 slip and continuous grain boundary migration or recrystalliza-tion,= grain boundary Sliding,7-9,13,14 and dislocation glide.'5 In this paper, experimental observations will be reported which support a model involving slip and continuous grain boundary migration or recrystalliza-tion. Specifically, a correlation will be made between this model and the development of elliptical cross sections as originally round specimens are superplas-tically deformed. For the most part, superplasticity studies have been conducted with eutectic or eutectoid alloys. Probably the most thoroughly studied material has been the monotectoid Zn-A1 alloy.1,2,6,12,13,15 No attention to the eutectic Zn-A1 alloy has previously been reported, and the results discussed in this paper represent part of a general study of the superplastic properties of this alloy. MATERIALS The alloys used in this investigation were prepared by melting appropriate quantities of 99.99+ pct A1 and 99.999 pct Zn in air, mixing, and pouring into a water- cooled stainless-steel mold. Wet-chemical analysis was conducted with each heat of alloy prepared, using the procedure of Fish and smith.16 The composition of the eutectic alloy was 95.1 wt pct Zn. Ingots about 2 in. thick were rolled to 0.4-in. plate at about 300°C with a reduction of 5 to 10 pct per pass. Specimens were machined from the plate with the tensile axis parallel to the rolling direction. The specimens were round, with 0.150-in.-diam, 1.25-in.-long gage length, and 0.25-in.-diam threaded grip sections. EXPERIMENTAL PROCEDURE Specimens were mounted inside a uniform-temperature quartz tube which was surrounded by a double elliptical radiant furnace with a 12-in.-long uniform-temperature hot zone and a low thermal capacity. The tube extended through the top and bottom of the furnace and permitted rapid quenching of the loaded specimens when quickly filled with cold water at the conclusion of the test. The quench precluded any effects on specimen microstructure from a normal, slow cool. Constant stress was applied to test specimens by suspending a load on a constant stress cam of the type described by Hopkin.17 The design of this cam permitted application of a constant stress for elongations up to 200 pct. For greater elongation, approximately constant stress conditions were maintained by systematically reducing the load manually. RESULTS As part of an investigation of the superplastic properties of the eutectic Zn-A1 alloy, evidence was obtained for the development of elliptically shaped cross sections as originally round specimens were extended. For example, after an elongation of about 100 pct, a round specimen with an initial diameter of 0.150 in. became elliptical with major and minor axis of 0.128 and 0.88 in., respectively. Photographs are presented to illustrate the ellipticity developed during superplastic deformation, Fig. 1. The specimen shown was deformed at a stress of 500 psi, at a temperature of 285°C, and a strain rate of 2.28 x 10-2 min-1. The strain-rate sensitivity exponent* was measured at *The strain-rate sensitivity exponent, m, is defined as d In o/d In c where o is the steady-state flow stress and E is the strain rate. this temperature and in the strain rate range 10"3 to 10-1 min-1 was found to be about 0.5. This value is typical of those observed with superplastic materials. The material studied exhibited negligible strain hardening during superplastic deformation, the creep rate remaining constant under constant stress and temper-

Jan 1, 1969

By Robert F. Mehl

THE purpose of a symposium, I take it, is to gather together a group interested in a common intellectual field, in order to exchange views, and to appraise the state of knowledge. Symposia are the more successful, the greater the activity in the chosen field and the wider the range of applicability of the information gained. From time to time, as emphasis changes from one field of research to another, a given subject may enjoy popularity and later retire into a scientific somnolence, for fashions change even among engineers and scientists. The subject of this symposium, however, enjoys the advantages of wide applicability and of high current interest and productivity in results. It is a timely subject for a symposium; with much new information, surely metallurgical engineers should now devote an increasing attention to its application to practice. In beginning the symposium, I shall attempt briefly to appraise our basic knowledge in the field, to survey instances of practical usefulness, and to suggest where new work might be most productive of useful results. There are many examples of direct practical application of diffusion knowledge, and it is the purpose of the several papers in this symposium to review these. In this introduction I shall attempt to take a broad view, which, while it will but poorly serve the engineer in the solution of any given problem, may perhaps be of some use in assessing the state of knowledge in this field. RATE OF DIFFUSION Liquid Metals The process of diffusion among liquid metals, of gases in liquid or solid metals, or among solid metals, is ubiquitous, to say the least. The manufacture of alloys by the intermelting of metals, the addition of ferroalloys to molten steel, the deoxidation of molten alloys, all involve diffusion in the liquid state. The oxidation of molten copper for purposes of purification, the unsought oxidation of alloys generally during melting and casting, the reaction of liquid steel with oxidizing slags in the open-hearth furnace, the absorption of nitrogen by liquid steel, particularly in the bessemer furnace, all operate by the diffusion of gases in liquid metals. These processes have not been studied much from the viewpoint of rates of diffusion. Alloys are made by melting metals with stirring and with allowance of time for mixing (which is diffusion) but I know of no studies that seem to define the necessary times, and though in only very rare cases can faulty properties of the finished castings be ascribed to inadequate mixing, and though certainly in most cases, with stirring, the rate of diffusion is adequate to give sufficient mixing, a more quantitative treatment would be good to have. It is not wholly certain that thorough and sufficient mixing is at all times attained, for I suspect that ferroalloy additions to steel, and that additions of aluminum to steel as a deoxidizer, especially in the sampling of steels

Jan 1, 1944

By A. Phillips, D. H. Killpatrick, V. Kerlins

The tensile failure of two dispersion-strengthened Ni-20 Cr alloys was studied and compared to the fracture of a similar alloy with no dispersoid. The fracture characteristics were studied using electron fruc-tography and transmission electron microscopy. In all three cases, the mode of failure was found to be microvoid coalescence. The failure in the dispersion-strengthened alloys was found to have initiated at the particles. The size of the dimples in the fracto-graphs was found to be related to the spacing of the particles, but not to the total elongation before failure. The elongation before failure was found to be related only to the amount of dispersed phase. These results are compared to those predicted by a theoretical model of ductile failure. THE continually increasing strength requirements for creep-resistant materials capable of long life at service temperatures above 1600"F (875"C) have developed considerable interest in dispersion-strengthened nickel-base alloys. The high yield strength of these alloys results from the presence of a dispersion of fine particles of thoria which act to impede the normal motion of dislocations. Many theories have been presented to explain the role of the dispersion in the strengthening of these alloys. A good review of these theories is presented by Ansell.' The ultimate strength of such alloys is not only related to mechanisms raising the yield strength, but also to the amount of work-hardening which occurs. This work-hardening is determined by the work-hardening rate and the amount of plastic strain before failure. Since fracture limits the amount of plastic strain, a study was undertaken to gain a better understanding of the fracture mechanisms in these alloys. Electron fractography and transmission electron microscopy were used to study the fracture characteristics in two dispersion-strengthened alloys and one similar alloy containing no dispersoid. These results are related to the tensile properties of the dispersion-strengthened alloys at room temperature and at 2000°F (1095°C). The results are also related to a theory for ductile fracture. 1) PROCEDURE Standard tensile specimens were made from 0.020-in. (0.051-cm) sheets of three different Ni-Cr alloys. The alloys had nominal compositions of Ni-20Cr, Ni-20Cr-2Th0,, and Ni-2OCr-4Th0,. All alloys were supplied in an annealed condition. The specimens were fractured in tension at room temperature to determine the effect of the dispersed thoria on the fracture appearance. The tensile properties were determined from the average of a minimum of three ten- sile specimens for each condition tested. The fracture surface of all of the alloys was examined by electron microscopy using standard two-stage plastic-carbon replica techniques. Thin foils of the dispersion-strengthened alloys were used to investigate the size and spacings of the dispersion particles, and to investigate sections of the 2 pct thoria alloy taken from areas of the specimen adjacent to the fracture surface. The thin foils were mechanically ground to 0.010 in. (0.025 cm) and then chemically polished to approximately 0.001 in. (0.003 cm) in a solution of 29 g of ferric chloride and 10 ml hydrochloric acid in a liter of water. The polishing solution was maintained at 150"F (65°C) during the thinning operation. The final thinning of the foil was done electrolytically using a solution of 700 ml ethanol, 100 ml 2-butoxy eth-anol, 120 ml distilled water, and 78 ml perchloric acid (70 pct). The potential was maintained at 15 v and the bath temperature at -20°~ (-29°C) during the thinning operation. The final thickness of the foil was approximately l000A as determined from the width of twins boundaries observed in many of the foils. 2) RESULTS AND DISCUSSION The electron fractographs of the fracture surfaces of the alloys are shown in Figs. 1, 2, and 3. The normal interpretation of this type of fractographz is that, as a result of the difference between elastic and plastic properties of the matrix and the particles or other inhomogeneities in the alloy, microvoids are formed

Jan 1, 1969

By E. W. Johnson, M. L. Hill

Equilibrium concentrations of hydrogen in iron were measured at H2 pressures up to 136 atm and temperatures down to 145°C. Residual hydrogen was prominent near 600°C in air-melted but not in vacuum-melted iron. The diffusible hydrogen solubility is abnormally high below 390°C, confirming the hypothesis of hydrogen trapping.' It appears that the traps for hydrogen in iron form suddenly on cooling. The estimated H2 pressure in equilibrium with 5 ppm hydrogen in steel at room temperature is less than 1000 atm. It was shown previously1 that the diffusivity of hydrogen in a-Fe below 200°C is anomalously low, a behavior attributed to the presence in the metal structure of hydrogen "traps." The energy of the trapped hydrogen was computed as 4.8 kcal Per g-atom below that of the interstitially dissolved hydrogen. The strongest confirmation of the trap hypothesis should be obtainable from measurements of the hydrogen solubility at low temperatures. such measurements have been performed and are reported in this paper. The "residual hydrogen" effect1'' must be carefully controlled if valid measurements of the solubility are to be obtained, and such an effort was made in the present work. Previous data for the solubility of hydrogen in iron have been summarized by Geller and Sun.3 Their equation for the most probable solubility at 1 atm in a-Fe above 400°C is

Jan 1, 1962

By Wilbur I. Duvall, Thomas C. Atchison

Over the past ten years a series of investigations have been conducted to determine some of the physical processes involved in breaking rock with confined concentrated charges. Detailed discussions of many of these investigations have been published elsewhere.1-6 Laboratory experiments made by other investigators using Hopkinson pressure-bar techniques have shown that solid materials are fractured in tension by the reflection of an incident compressive stress pulse at a free surface.7-12 In these tests a small charge of explosive is placed in contact with one end of a bar. Detonation produces some plastic flow and crushing of the bar near the charge and generates a compressive stress pulse that travels along the length of the bar. At the free end of the bar the compressive stress pulse is reflected back into the bar as a tensile stress pulse. If the tensile strength of the bar is exceeded during this reflection process, a tensile fracture normal to the length of the bar is produced, and the broken end of the bar moves forward with a constant velocity equal to the average particle velocity trapped in the broken fragment. The new surface formed by the fracture becomes the new free end of the bar that reflects the remaining portion of the incident compressive stress pulse. This process is repeated any number of times until all of the incident stress pulse is reflected.

Jan 6, 1959

By W. J. Babyak, F. N. Rhines

It has long been supposed that, regardless of the mechanism by which grain boundaries increase the hardness of a ductile metal, the effect should be linearly proportional to the grain boundary area. At the present time two methods for determining grain boundary area in an isotropic aggregate are available. The first, derived by Angus and Summers,' presumes that the grain boundary area is equal to 3vn, where n is the number of grains per sq mm in a random section through the metal. This estimate is based upon the assumption that the grains are equivalent to cubes whose faces correspond with the grains as observed in the micro-section. Measurements on copper, bronze, and a brass showed that a nearly linear relation exists between 3vn and hardness. This is illustrated, for the case of brass, in Fig. 1. The second method, developed independently by Smith and Guttman2 and by Duff in, Meussner, and Rhines,3 is absolute and employs a simple linear intercept count for measuring grain boundary area. It involves no assumptions with respect to the shape and distribution of the grain boundaries. The total surface in unit volume is 2 NL , where NL is the number of intercepts between grain boundary and unit length of a test line passed randomly through the sample. In practice, NL,, the average number of grain boundaries intercepted by unit length of traverse across a prepared microsection, is ob-

Jan 1, 1961

By Ramkrishna Agarwal

The problem of the measurement of in situ stresses in rock masses has, in recent years, become one of the prime concerns of investigators and researchers in the field of rock mechanics. Numerous instruments have been developed for that purpose and various techniques have been used to determine the absolute values of these stresses at a point.l The "stress-relief" technique has gained the widest acceptance. In its usual application it relies on one of the two following principles: (1) Measurements of the changes in a "solid inclusion" in a borehole,2 or (2) Measurements of the diametral deformation of a borehole with a free boundary." The theoretical development, in the case of the latter, is based upon an evaluation of the deformation of a circular hole in an infinite plate under the action of a uniaxial stress field. Expressions for the deformations may be obtained by using either the plain strain or the generalized plane stress theoretical approach of the classical theory of Elasticity, which assumes that the material is linearly elastic, homogeneous and isotropic. The solution for the case of a biaxial stress field is obtained by the Principal of Superposition. The circular hole becomes elliptical after deformation takes place under the action of a uniaxial or biaxial stress field applied to the plate. In the practical application of the technique, the reverse procedure is applied. A borehole is drilled in the rock and a deformation-measuring

Jan 1, 1968

By Robert R. Turner, Arthur R. MacPherson

This chapter reviews the steps which should be taken from the time it is decided to consider autogenous grinding in the development of a new ore deposit or the expansion of an existing plant up until the purchase of the new autogenous mills. In this case the term autogenous includes semi -autogenous, secondary pebble mills, and lump milling as well as fully autogenous grinding systems. Also, both wet and dry grinding alternatives have been included. Before the test program it must be decided how many bulk samples are required to properly assess the autogenous grinding possibilities of the deposit. Also, a decision must be made on where and how the samples are to be ground i.e. pilot mill at site or in established location, wet and or dry grinding, etc. In the test program itself, certain fundamental data must be obtained. The testing should include enough work to determine whether fully autogenous or semi-autogenous grinding should be used and what type produces best power efficiency. Also, all the other pertinent data should be collected such as power; tonnages; feed, charge, and product sizing; circulating loads, etc. If a secondary mill is required to produce a final grind the decision on whether a pebble or ball mill should be used may require additional test work. Finally, the concentration of the mineral may play an important part in selection of the circuit and should become a part of the final testing once the grinding has been established.

Jan 1, 1978

It is claimed that the first mining of copper by Americans in Arizona was done at Ajo, near the Mexican border, in 1854,* a year after this region had been added to the United States, under the terms of the Gadsden purchase. A group of adventurers, organized at Los Angeles under the name of the Arizona Mining & Trading Company, came, to the district. This party of prospectors consisted of 20 men, led by Major B. Allen, J. D. Wilson, and William Blanding. † They went first to Yuma, where the party divided, some of them going southward into Mexico while the remainder took the trail to Tinaja Alta, where they heard of the copper deposits of Ajo, which is 85 miles southeast from Yuma.‡ They found attractive outcrops of copper ore, and set to work energetically, but their operations suffered many interruptions, because that part of the country was still controlled by the Mexicans, who were uncertain about the exact position of the new international boundary. The Mexicans tried to expel them, but they held their ground. The first shipment of ore, consisting of native copper and cuprite, came from what is now the western end of of the New Cornelia workings; it was hauled in ox-carts to San Diego, 400 miles across the desert. § Later shipments were hauled to Yuma and floated on barges down the Colorado river to the Gulf of California, whence the ore was loaded on

Jan 1, 1932

In recent years, with the advent of new steelmaking procedures, the emphasis has turned away from conventional teeming and has been directed toward continuous casting. This paper points out the fact that there are still new methods being considered to decrease the problems and costs associated with conventional teeming. Although Inland has had no experience with the repair of mold lugs, we do find some problem with damaged ears associated with mechanically capped steel. When pouring bottle tops, any crane movement or leak from the pouring nozzle may result in steel over the top of the mold which, in turn, may result in the shearing of the mold lugs during stripping. Recent back pouring practices increase the chances of this occurring. At Inland's steelmaking shops, we have tried to combat this problem by various methods such as burning the steel from around the top of the mold at the pouring stand with oxy-gas torches. Last year, No. 4 BOF began a conversion from round to elliptically shaped bottle top caps. This change has greatly reduced the chance of splashing due to crane swing by increasing the dimension in the direction on normal swing. The answer to this particular problem is, however, tighter control of pouring performance. We are presently engaged in a process of re-education of personnel and experimentation with different materials and designs of nozzles, heads, and sleeves to help us achieve our goal.

Jan 1, 1972

The following is an incomplete list of members and guests who called at Institute headquarters during the period June 10, 1919, to July 10, 1919. Anvil A. Anderson, Rapid City, S. D. Roy N. McBride, U. S. Army. R. Hay Anderson, Mexico City, Mex. R. S. McIntyre, Berkeley, Calif. W. A. Barnes, San Francisco, Calif. H. R. Maier, Brooklyn, N. Y. Bennett R. Bates, Denver, Colo. Wm. D. Mainwaring, Philadelphia, Pa. Harlan H. Bradt, Duluth, Minn. Wm. E. Milligan, Chrome, N. J. H. Brings, San Francisco, Calif. Willard S. Morse, Tacoma, Wash. Robert S. Burg, Ocean Park, Calif. Arthur Notman, Bisbee, Ariz. D. W. Butner, Congo Belge, Africa. P. Nugue, Chalon Sr. Saone, France. George A. Camphuis, El Paso, Tex. George A. Packard, Boston, Mass. Fred Canan, Denver, Colo. C. L. Petzel, New York City. Walter H. Coleman, Prescott, Ariz. V. Porreaud, Paris, France. Fred Crabtree, Pittsburgh, Pa. Fred S. Porter, Seattle, Wash. Ross E. Douglas, Rancagua, Chile. R. W. Prouty, Morenci, Ariz. F. A. Downes, Golden, Colo. Charles E. Prior, Brooklyn, N. Y. W. G. Eberhardt, Tucson, Ariz. Louis Ravicz, Minneapolis, Minn. Charles H. Fulton, Cleveland, Ohio. Wm. Reed, El Oro, Mexico. Wm. R. Grunow, New York City. E. J. Ristedt, Globe, Ariz. Orr R. Hamilton, Lansing, Mich. A. M. Rodgers, Middletown, N. Y. T. N. Havlin, St. Louis, Mo. J. C. Scoles, Salt Lake City, Utah. G. M. Henderson, Weston, Mass. C. E. Siebenthal, Washington, D. C.

Jan 8, 1919

Papers presented at two joint meetings of the Mineral Industry Education Division, Geophysics Committee, the American Geophysical Union and the Committee on College Curricula of the American Association of Petroleum Geologists, at the A I M E meeting in New York on Feb 17 and 18, 1941 At the first meeting, the Musing Geology Committee, the Society of Economic Geologists and the Committee on Applications of Geology of the American Association of Petroleum Geologists also took part [ ]

Jan 1, 1941

Papers presented at two joint meetings of the Mineral Industry Education Division, Geophysics Committee, the American Geophysical Union and the Committee on College Curricula of the American Association of Petroleum Geologists, at the A I M E meeting in New York on Feb 17 and 18, 1941 At the first meeting, the Musing Geology Committee, the Society of Economic Geologists and the Committee on Applications of Geology of the American Association of Petroleum Geologists also took part [ ]

Jan 1, 1941

[ZAY JEFFRRIES, Vice-chairman PAUL D, MERICA, Chairman W, M, CORSE, Secretary Executive Committee J. It, FREEMAN, JR., Local Section S. SKOWRONSKI, Papers Committee R. S, ARCHER, Non-ferrous Data Sheets H, C, JENNISON, Membership Committee E, C, BAIN, Journal Committee L, W. SPRING Local Section Committee J. R, FREEMAN, JR,, Chairman R. J, ANDERSON, Cincinnati R. L. DOWDELL, Minneapolis R. S. WILLIAMS, Boston G, H, CLAMER, Philadelphia W. A. SCHEUCH, Chicago R, F, WOOD, New York]

Jan 1, 1928

President and Director GROVER J HOLT, '59, Ishpeming, Michigan Past President and Director CARL E REISTLE, JR, '58, Houston, Texas President-elect and Director AUGUSTUS B KINZEL '60, New York City Vice-Presidents and Directors W A DEAN, '58, Cleveland Ohio W W MEIN, JR, '58, San Francisco, Calif L E ELKINS, '59, Tulsa, Okla J L GILLSON,'59, Wilmington, Delaware E C BABSON, '60, Calgary, Alberta, Canada R V PIERCE, '60, Salt Lake City, Utah

Jan 1, 1957

By Freeman Bishop

The Bureau of Mines is working on a long-term program to completely revolutionize mining-to create a mine-systems technology that integrates the need to recover minerals at low cost under safe and healthful working conditions while protecting the environment. Everyone should be brought into the planning process preceding each new mining development, the Interior Department urges, and Assistant Secretary Hollis M. Dole seems determined to push this kind of systems approach with everything he can move.

Jan 1, 1970

By F. J. Deadrick, A. L. Ramirez, R. J. Lytle

This article describes the evaluation of a new geophysical technique used to map fractures between boreholes: electromagnetic geotomography used in conjunction with salt water tracers. An experiment has been performed in a granitic rock mass. Geotomographic images have been generated and compared with borehole geophysical data: neutron logs, acoustic velocity logs, caliper logs and acoustic televiewer records. Comparisons between the images and the geophysical logs indicate that clusters of fractures were detected but single fractures were not.

Jan 1, 1982