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By Irving Crosby

ELECTRICAL prospecting by potential methods has been applied to mining problems for some years and determinations of the depth to bed rock have been made, but so far as is known it has not been used previously in the solution of civil engineering problems, such as investigating the foundations of dams. During the past winter and spring the senior author has been engaged as consulting geologist in studying the site of a large darn on the upper Connecticut River and has had the satisfaction of introducing electrical prospecting to foundation problems. The valley across which the dam is to be built is underlaid by a deeply buried preglacial gorge which is filled with glacial deposits. An extensive drilling campaign was in progress, but the work was unusually slow and expensive on account of the number of boulders in the overburden. The necessity of speeding up the work was pressing and it was decided that much of the needed information could be obtained by geophysical methods. After investigating the various methods and conferring with the company engineers and with the consulting engineer, Albert Crane, a contract was made with the Schlumberger Electrical Prospecting Methods, and an observer with apparatus was sent to the dam site the first of April, 1928. The problem was to determine the depth to rock at various points in order to prepare a contour map of the bed-rock surface and outline the buried gorge in the vicinity of the dam site. Over one hundred determinations of depth have been made and the bed-rock topography, is now known in considerable detail. In addition, some information has been obtained about the nature of the overburden. The drilling has been continued; in fact, two additional drills have been put to work, and the electrical determinations have been checked at several points. At one of these the depth to rock given by the electrical work was 142 ft. and the drill found rock at 147 ft., an error of less than 4 per cent. The electrical work has also been checked by the geological study, and it has been found that when the electrical determinations are in agreement with the geological expectations they are probably reasonably accurate. When the electrical interpretation of the sub-surface topography is incon-

Jan 1, 1928

By W. S. Hyler, L. W. Berger, R. I. Jaffee

Hydrogen additions of 390 ppm to A-55 titanium and 368 ppm to Ti-8 pet Mn have no deleterious Hydrogenadditionseffect on the unnotched and notched rotating-beam fatigue properties of these materials. 'These amounts of hydrogen, however, are sufficient to cause severe notch-impact thesematerials.embrittlement in A-55 titanium and pronounced loss of tensile ductility in Ti-8 pet Mn. The lack of embrittling effect in fatigue in the latter alloy is consistent with the postulated strain-aging mechanism of hydrogen embrittlement in a-ß alloys. There is a significant strain-agingincrease in the unnotched endurance limit of A-55 titanium with the addition of hydrogen. This increase may be explained as the result of internal heating effects which would dissolve the hydride and cause solid-solution strengthening. TITANIUM and its alloys may be seriously embrittled by relatively small amounts of hydrogen. The form which this embrittlement takes has been shown to vary with alloy type. The a alloys, for example, suffer most strongly from loss of notch-bend impact toughness' when sufficient hydrogen is added, and this effect has generally been associated with the presence of hydride phase in the micro-structure. In a-ß alloys, on the other hand, hydrogen is most detrimental to tensile ductility in slow-speed tests,2-1 and the embrittlement may be detected in a most convincing manner by means of rupture tests at room temperature. This particular kind of embrittlement has not been associated with a change in microstructure, but has been classified rather generally as associated with a strain-aging type of mechanism.' In the present paper, the effect of an embrittling amount of hydrogen on the rotating-beam fatigue properties of both an a and an a-ß titanium alloy is covered. For this study, annealed commercially pure (A-55) titanium was chosen as an a alloy, and equilibrated and stabilized Ti-8 pet Mn as representative of a typical a-ß alloy. Nominal hydrogen levels of 20 and 400 ppm were evaluated, the latter amount having been shown previously to be severely detrimental to the impact toughness of commercially pure titanium and to cause pronounced strain-aging embrittlement in the Ti-8 pet Mn alloy. The only report of the effect of hydrogen on the fatigue properties of titanium is given by Anderson et al.,° in which a push-pull type of fatigue test was conducted on as-received commercial-purity titanium sheet. Much scatter was found in the results, but generally the presence of hydrides slightly decreased the fatigue strength of unnotched specimens in the longitudinal direction. The results of notched tests were masked too greatly by scatter to be significant. Experimental Procedure Preparation of Materials—Analyses of the A-55 titanium and the Ti-8 pet Mn alloy used in this investigation are given in Table I, which indicates the 8 pet Mn alloy to be more nearly a 6 pet Mn alloy. This alloy will be referred to as Ti-8 pet Mn, however, since this is the commercially designated composition. Both alloys were received in the form of5/8-in. diam rod and, after suitable surface preparation, 5-in. lengths were vacuum annealed at 820°C. Half of the rods for each material were then hydrogenated at 820°C to a nominal hydrogen content of 400 ppm. The hydrogenated and vacuum-annealed A-55 rods were hot swaged at 700°C from 5/8-in. diam to 1/4-in. diam, and then annealed 1 hr at 800°C and air cooled prior to preparation into test specimens. Fabrication of the Ti-8 pet Mn alloy was by hot swaging to 3/8-in. diam at 760" and then 1/4-in. diam at 704°C. This material was then annealed 1 hr at 704", followed by furnace cooling to 593"C, and finally air cooling to room temperature. Evaluation—In order to examine more completely the effects of hydrogen on the particular materials studied, slow-speed tensile and notch-bend impact properties were determined in addition to fatigue data. Tensile specimens were of the standard ASTM type with a reduced section of 1/8-in. diam and a gage length of 1/2 in. A subsize cylindrical Izod specimen was used for impact tests. These specimens had a 45" notch with a 0.005-in. radius and a 0.150-in. root diam, and the stress concentration factor of this notch in bending was Kr = 3. Both the ten-

Jan 1, 1959

By Lyman Taylor, Alexander R. Troiano

STUDIES of the transformation of austenite at constant subcritical temperatures have been numerous since the work of Davenport and Bain.1 Considerable information has been obtained on low-alloy steels and on high-carbon alloys containing undissolved carbide or graphite at the austenitizing temperature. Little is known of the isothermal transformation of austenite containing in solution large amounts of both carbon and a single alloying element. In this investigation four steels containing one per cent carbon and with chromium in the range 3 to 9 per cent have been examined with the view to establishing the fundamental character of the isothermal reactions when all carbon and chromium are initially in solution in austenite. EXPERIMENTAL PROCEDURE Alloys The chemical compositions of the steels investigated are given in Table I. The 4 per cent Cr alloy is a commercial steel. The other steels were made by the Carpenter Steel Co. as 50-lb., induction-furnace heats and rolled to 5/8-in. round bars. Bars were softened at 650° to 700°C. before the specimens were cut. [ ] Metallographic Method Most of the lines on the transformation diagrams presented here have been placed on the basis of the microscopic examination of partially reacted specimens. Thees specimens were approximately ½ by ¼ by 1/8 in. in size. Specimens of the 9 per cent Cr steel were held 10 to 12 hr. at 1200° to I225°C. before quenching to the various subcritical temperatures. The other steels were held for 2 to 2 ½ hr. at 1200°C. before quenching. These treatments, carried out in an atmosphere of purified nitrogen, produced an austenite grain size larger than A.S.T.M. No. I, some grains being 1 to 2 mm. in diameter. There were a few undissolved carbide particles in some specimens of the 9 per cent Cr steel. It is believed, however, that any errors in the results due to incomplete solution of carbon and chromium in austenite are negligible; that is, austenite compositions may be considered as being those listed in Table I. X-ray Methods Constituents were identified and martensite axial ratios determined from Debye

Jan 1, 1945

W. E., RUDER, Schenectady, N. Y. (written discussion *).-Professor Howe, with characteristic thoroughness, has demonstrated that Professor Jeffries' "Reversed Inheritance" explanation of the case in question is contrary to fact, as shown by many previous observers. Since the photographs were my own, I feel it my duty to say a few words in discussion. In the first place, it is to be noted that these photographs were of pressed powders, and although many of Professor Jeffries' original experiments were made from this kind of material, the nature of such a specimen must of necessity be different from that of the fused metal, although the same basic laws of grain growth may apply in both cases, certain factors, such as the rate of change, for example, are undoubtedly different in each case. That the 1000° C. grain is a natal grain is evident from its appearance contrasted with the more perfectly formed, though smaller, grains in the 1300° C. photograph. I am not sure that Professor Howe's explanation of the formation of this grain is necessarily the correct one, although it agrees with. Stead and Carpenter's results. I am inclined to think that this grain may have been formed on heating, because I have been able to produce grains of the shape and magnitude of Stead and Carpenter's grains by heating to 850° C. pure electrolytic iron, which has been subjected to a strain gradient. On reheating to 1300° C., the mobility being so much greater, the individual crystals had time for unhampered re-arrangement and growth after their second refinement on passing Ac3, so that we have in this case a true fused metal condition in which the individual crystals are arranged in true equiaxed grains of a size consistent with their high temperature anneal. In this case the grains are equiaxed, inheriting none of the columnar tendencies of the previous grain, because they were not affected by any strain gradient, except possibly some accidental local gradients. It seems to me that the introduction of pressed powders into the discussion of grain growth, where allotropic changes take place, unnecessarily complicates an already complicated problem.

Jan 1, 1918

Prior to World War I, zinc was universally made by the distillation process. Small plants were operated at Cockle Creek, N.S.W., and Port Pirie, S.A. Then the electrolytic process was developed at Great Falls, Mont., in 1915 and at Trail. B.C. encouraging the Broken Hill companies to investigate the process. England's war-time need for zinc gave impetus to the development, and the site at Risdon, Tasmania, coincided with the developing hydro-electric power there. Experimental work was begun in 1917 by a proprietary company formed and owned by Broken Hill interests. Then in 1920, the principal features of the process having been established, a public company. Electrolytic Zinc Company of Australasia Ltd. was formed, now known as E.Z. Industries Ltd.

Jan 10, 1964

By C. R. Simcoe, T. J. Koppenaal

The effect of direct and alternating currents on the quench aging behavior in an Al-4 pct Cu alloy has been investigated by use of resistivity measurements. The reaction rate increases with direct current density in the investigated range of 1000 to 3000 amps per sq cm. Alternating current of a specific frequency is observed to decrease the reaction rate by a factor of about two. ErDMANN-JESNITZER et al.,1,2 investigated the effect of direct and alternating current on the quench and strain aging behavior of low-carbon iron. In both cases they observed that direct current accelerates the aging reaction and that an alternating current can completely inhibit the aging process. The purpose of the present research was to investigate these phenomena in the quench aging behavior of an Al-4 pct Cu alloy and to determine the correlation, if any, between the increase in the observed reaction rate and possible heating effects accompanying the aging with direct current. EXPERIMENTAL PROCEDURE The aluminum-base alloy used in this investigation contained 3.98 wt pct Cu (1.72 at. pct) with impurities of 0.003 pct Si, 0.002 pct Fe, and 0.001 pct Mg. The alloy was rolled into a ribbon about 0.36 mm thick and 3.7 mm wide. The ribbon was split end from end with the ends being used as electrical contacts and the central unsplit section, about 5.3 cm in length, serving as the specimen. Solution treatment was accomplished by quenching from a salt bath at 520° ± 2°C into water at 25° ±0.5°C; the specimen was immediately transferred to a liquid nitrogen bath. All aging was done at 75° ± 0.2°C in a rapidly stirred ethylene glycol bath. Resistivity measurements were made by the double potentio-metric method employing a standard resistor; for purposes of convenience, the resistance measurements were made at 77°K. The transfer of the specimen from the aging bath to a liquid nitrogen dewar was accomplished in less than 1 sec. The aging kinteics were studied with the specimen being aged under the influence of direct current, alternating current, and without any type of current. The amount of heating caused by direct currents was investigated by soldering a thermocouple on the specimen surface and measuring the temperature change after applying various current densities. The temperature was observed to increase (from 75°C, the aging temperature) about 0.8°, 3.0°, and 8.5°C with direct currents of 1000, 2000, and 3000 amp per sq cm, respectively. When employing alternating current, the circuit was monitored with an oscilloscope and adjustments made to produce a normal sine-wave pattern. RESULTS Prior investigations3'4 in the aging characteristics of A1-4 wt pct Cu have shown that the resistivity initially increases, reaches a maximum, and then decreases to values significantly lower than the as-quenched resistivity. This type of behavior is seen in Fig. 1 which shows the resistivity at 77°K as a function of aging time at 75°C observed in this investigation. At this aging temperature, the resistivity maximum is seen to occur in about 1 to 1-1/2 min and it further decreases to the as-quenched value in about 24 min. The behavior observed with the application of direct currents of 1000, 2000, and 3000 amp per sq cm during aging is shown in Fig. 2. With increasing current densities, (+) ?pmax decreases and the rate of the aging process increases. The time necessary to reach the as-quenched resistivity value decreases from 24 min for aging without current to about 16, 10, and 7 min for aging with 1000, 2000, and 3000 amp per sq cm direct current, respectively. Fig. 3 shows the results obtained when two changes were made during the aging with 2000 amp per sq cm

Jan 1, 1963

By G. R. Countryman, G. H. Thomas, I. Fatt

Procedures are described for scaling up turbulent friction pressure drops of inelastic fluids and laminar friction pressure drops of inelastic/elastic fluids in circular ducts. The laminar scale-up calculation method does not require the use of arbitrarily defined flow models, and can be performed directly from laminar capillary viscometry data, or by means of a numerical solution of the integral equation for Poiseuille flow, inputing true shear rate-shearing stress data from other simple shearing experiments. e.g. Couette and plane Poiseuille flows. The turbulent scale up procedure, based on the Dodge-Metzner correlation for inelastic fluids, requires evaluating the characteristic rheological parameters at the existing wall stress under laminar flow conditions. Since the wall stress is the quantity sought in a pipe flow scale-up problem, a trial-and-err or solution is indicated, and therefore a calculation method has been developed and programmed for a medium-size magnetic-drum-memory digital computer. Laminar flow data from other somces may also be adapted to this turbulent scale-upmetbod for inelastic fluids. Comparisons between predicted and experimentally observed friction losses for generalized Reynolds numbers ranging from 3 — 32.000 indicate an error band width of less than 10 per cent in circular tubes ranging in size from 0.5 to 1.89 in. in diameter. INTRODUCTION Considerable effort has been devoted to the problem of establishing an accurate procedure for predicting the laminar and turbulent flow behavior of non-Newtonian materials in pipes from data obtained with small scale laboratory or pilot plant equipment, as evidenced by the variety of reviews on the subject.1-3 Although there does not appear to be a universally accepted scale-up method for laminar flow, the various methods currently employed can be divided into two principal categories depending upon whether a functional relationship between shear rate and shearing stress is assumed, or whether a generalized correlation is adopted. The methods of Hedstrom4 and of Weltmann are typical of the first category, while the generalized correlation of Metzner and Reed6 illustrates the second category. Under appropriate conditions either approach yields a reasonably satisfactory description of laminar flow behavior. In contrast, the prediction of non-Newtonian transitional and turbulent friction losses is much more complex. For example, certain types of materials have been observed to sustain laminar flow at much higher flow rates than Newtonian liquids. When turbulence does develop, the level of agitation is damped to such an extent that the friction factor is lower than that of the original low viscosity Newtonian medium. Extremely broad transition regions and "diameter effects" have also been noted in the turbulent flow of certain chemically complex materials.' Aside from the latter complications, which are attributed in part to viscoelasticity, the existence of a variety of scale-up procedures for predicting transitional and turbulent friction losses is due principally to the chioce of viscosity parameter used in the definition of the Reynolds number. In contrast, Dodge and Metzner have demonstrated that the friction factorReynolds number relationship for inelastic fluids can be satisfactorily generalized provided the fluid property parameters are evaluated at the existing wall shearing stress.* However, the quantity usually sought in a pipe flow scale-up problem is the wall stress, and hence a trial-and-error procedure is required when dealing with non-power law materials. In this report we discuss two calculation methods: (1) for determining the wall stress, and hence the friction pressure drop, for inelastic fluids under conditions of turbulent flow by means of an iterative procedure, and (2) for predicting laminar friction pressure drops without recourse to arbitrarily defined flow models.

By M. H. Pilkuhn, H. Rupprecht

p layers on n-type substrates of GaAs were prepared by difhsion of zinc into these substrates. Experimental details about the diffusion technique will be presented. It will be shown that inhomogeneity in the substrate doping level and crystal shucture defects cause nonplanarity in the junction plane. These nonplanarities give rise to high threshold current densities. From incremental sheet-conductivity measurements the zinc profile is derived. Data about surface concentration and gradient of the zinc concentration at the junction are presented. Finally, some results of laser diodes, which were made of wafers with extremely planar diffusion fronts, are discussed. ThE investigations reported here are part of a program concerned with the materials aspect in the fabrication of GaAs laser diodes. This includes studies of the influence of crystal defects introduced both during the growth of the crystal and as a consequence of subsequent diffusion. Compared with the progress made in the investigation of structure defects, for instance by X-ray microscopy in materials like silicon, no similar results are known so far for the case of GaAs. The further progress in laser diodes will depend very much upon our knowledge of these structure defects and subsequently upon our ability to avoid them. Laser diodes of GaAs had been made mostly by diffusing an acceptor impurity, normally zinc, into an n-type substrate. This procedure was found more convenient than the inverse one for various technical reasons. We will follow this line and restrict ourselves to zinc diffusion only in this paper. DIFFUSION TECHNIQUES AND EXPERIMENTAL DETAIL In order to set a refgrence for our experiments, we used a standard procedure for the diffusion runs. The diffusions were carried out in a sealed quartz tube for 2-1/2 hr at 850°C. One milligram zinc arsenide (ZnAsz) per cu cm of the tube volume served as zinc source. Under these conditions the junction depth was between 25 and 30 p. It is assumed, according to the investigations of the zinc arsenide system by V. Lyons and V. ilvestri,' that ZnAs2 dissociates completely at 850°C into ZnsAsz and Asg. Since there is a condensed phase of ZnsAs2 in the tube at 850°C, the partial pressure of zinc is controlled by the pressure of the arsenic formed by the dissociation of ZnAs2. Due to the fact that the zinc partial pressure resulting from the dissociation of ZnsAsz is only a weak function of the partial pressure of arsenic, the amount of the initial ZnAs2 is not very critical. Experimentally, we found that the junction depth, as well as the surface concentration, was practically the same, if the ingots of ZnAs2 varied between 0.2 and 5.0 mg per cu cm. The wafers were oriented with the main faces in (100). Surface damage due to cutting and lapping was removed by a chemical-etch treatment in a rotating beaker (etch solution: HzSOr, H202, and HzO in a ratio 3:l:l). The GaAs substrate material was n type and doped with tellurium, selenium, silicon, or germanium. It was grown by means of horizontal or Czochralski techniques. After the diffusion process, junction depth and planarity were checked either by grooving with a

Jan 1, 1964

[Appalachian Petroleum Section: James M. Kimbrough, chairman; John H. Adair, first vice-chairman; Walter L. Diddle, second vice-chairman; Byron M. Finch, secretary-treasurer. Balcones Section: Robert V. West, chairman; Frank W. Jessen, first vice-chairman; Zane V. Morgan, second vice-chairman; Brantley G. Myers, secretary-treasurer. Meets 4th Wed., Petroleum Club (San Antonio) or Terrace Dining Room (Austin) Billings Petroleum Section: Charles B. Evans, chairman; L. M. Lyon, first vice-chairman; Gordon E. Lansford, second vice-chairman; Fred. A. Haddenhorst, secretary-treasurer. Meets 3rd Tues., Billings Petroleum Club. California Coastal Section: Robert L. Richardson, chairman; David K. Hayward, first vice-chairman; W. Jackson Bransford, secretary; William N. Harwell, treasurer. Meets 3rd Thurs., Pierport Inn, Ventura. Caracas Petroleum Section: Edwin A. Moo re, chairman;. Jose Cirigliano, vice-chairman; Frank B. Davis, secretary; Robert N. Powers, treasurer. Meets 2nd Tues., Caracas Theater Club.]

Jan 1, 1961

Research and Development, once considered a luxury item only for well-heeled companies, has in the last two decades come into its own as a vital contributor to the fortunes of electronic, automotive, chemical and aerospace firms. In terms of money and talent poured into research, the mining industry is still far behind those industries. Although the U.S. Bureau of Mines, plus various mining and manufacturing firms and universities have made notable contributions to mining technology, the historical pattern of mining R&D shows a heavy reliance on the results of research in other industries. It is difficult to tell whether this pattern will change significantly in the future, but there is evidence of a growing awareness by mining officials that greater R&D efforts are going to be required not only to meet the nebulous demands of tomorrow's world but to meet the ever-present, mounting pressures being generated by "intra-metals" and "inter-materials" competition.

Jan 1, 1968

By Robert M. Lewis

Can wet-ground mica be produced from mica schist ores, and if so, would its properties be comparable with products now on the market? This was the problem which prompted the development of a flowsheet for the beneficiation of mica schist. The fine-ground mica industry relies on weathered pegmatites and alaskite ores as sources of raw material. The mica concentrates obtained from these ores are relatively clean and require moderate beneficiation to meet color and bulk-density specifications. Mica obtained from mica schist is iron-stained and decrepitated and requires additional beneficiation to produce a wet-ground mica product. Despite these adversities, there are several advantages to be gained by mining and processing mica schist ores. The mica content of these ores is considerably higher than that of the pegmatites and alaskite ores now being mined, often containing in excess of 40% mica. This higher-grade mica feed should promote a lower mining and milling cost. The mica schist ores with their higher mica content would mean less tailings to handle; however, there would have to be a means for disposing of acid and sulfate wastes. A flowsheet was developed whereby mica could be recovered from mica schist ores and beneficiated in a way that would result in a high-quality end product.' The essential phase of the process involves using reducing reagents to increase the magnetic susceptibility of iron contaminants which then can be removed with a magnetic separator. General Treatment Procedure The mica is floated by either of two methods, an amine float in an acid circuit' or the U.S. Bureau of Mines (USBM) amine-fatty acid float in an alkaline circuit' The flotation mica is ground in a pebble mill to liberate contaminated particles and expose iron-stained surfaces. The concentrate is then conditioned with a reducing reagent and passed through a Frantz Ferrofilter for the removal of magnetic material. The nonmagnetic product is acid-leached to further reduce the iron contamination. The leached material is then ground to product size and checked for specifications. Discussion of Flowsheet and Its Development Flotation: The mica is concentrated by flotation using either of two methods: an amine float in an acid circuit, or the USBM amine-fatty acid float in an alkaline circuit.' The writer does not wish to elaborate on the relative merits of the two flotation procedures; however, after investigating ores from various localities, it was felt that the amine float in an acid circuit was more consistent when using a standard procedure. Iron Reduction and Magnetic Separation: This phase of the flowsheet may be considered the key to the process. It was developed when it became apparent that hot acid leaching had just about reached its maximum effective¬ness for color improvement. S. C. Sun and William Hirsh in "Hydrochloric Acid Leaching of Iron From Pennsylvania Aluminous Clays,"` reported iron extraction for -20-mesh minerals of 82.20% for hematite and only 33.46% for magnetite. The test procedure employs a 19% hydrochloric acid solution, 104°C temperature, and 10% solids. It was felt that magnetic removal of some of the iron contaminants before leaching therefore would be advantageous. Since the iron minerals present as contaminants vary in magnetic susceptibility, it was decided to experiment with reducing reagents as a means of influencing their magnetic properties. Zinc hydrosulfite or sodium hydrosulfite were the reagents used throughout the tests. The procedure developed consists of conditioning the mica concentrate in a closed container at approximately 5% solids with a reducing reagent. Approximately 10.0 lb of zinc hydrosulfite per ton of mica concentrate is used. The ferric iron is reduced to the ferrous state (magnetic) and oxidation is retarded by isolation from the atmosphere in a closed container. After the desired conditioning time has elapsed, the material is passed through a Frantz Ferrofilter where the magnetic particles are retained and discarded as

Jan 1, 1972

By James M. Link

Slurry transport of industrial minerals has proven to be practical, economical, and efficient. Industrial minerals currently being pumped for long distances include cement, clay, phosphate, sand, and various waste product from industrial mineral processing operations. This paper will touch upon the basic theory of hydraulic transport of solids and then consider the economic and engineering considerations upon which construction and operation of such a line would be based. Where possible, actual cost data will be presented.

Jan 1, 1974

By G. F. Leaming

The paper by R.V. Ramani and R.J. Sweigard is a wonderful description of the labyrinthine web that has been spun about the mining industry by energetic bureaucrats and politicians over the past 50 years. The remedy for the problem, however, is not more of the same, but less. That may be difficult for the industry to achieve, for it is not a technical solution but a political one. And the current fervor for more detailed planning at all levels of government and private enterprise has become deeply ingrained. The authors recommend the provision of more information about mining and mineral resources to "macro" (i.e., government) land use planners. They apparently overlook, however, the already strong tendency on the part of most government land use planners to consider themselves omniscient. Thus, giving them more information about the technical problems of mining will only make them want to get more and more involved in the "micro" (private, site specific) mine development and production plans of the individual mining firm. In fact, this has already happened at all levels of jurisdiction from municipal to federal government. Examples are legion. The most effective way to ameliorate the adverse impacts of government land use planning on existing and potential mining operations is to: (1) introduce greater flexibility in the definition of land use zones by local and state governments; (2) adopt realistic and relevant ambient environmental performance standards in governing relationships between mineral land uses and concurrent or subsequent nonmining land uses; (3) allow greater leeway for economic considerations in land use decisions in contrast to the explicit legalistic approach now in vogue; (4) recognize that all minerals are not the same and that sand and gravel mining should not be treated the same as underground metal mining, coal stripping, oil field production, or in situ leaching; and (5) eliminate the notion that mining operators should be responsible for determining in detail the use of land by subsequent owners of mined land. This last bit of conventional ethic really makes no more sense than requiring the builders of every shopping center or government office complex to provide detailed plans for the use of that land when its use for shopping or government is ended. Did the builder of Ebbetts Field plan for Brooklyn after the Dodgers went to Los Angeles? Should the developer of the Bingham Pit plan for suburban Salt Lake City after the copper mining goes to Chile? The nation's mining industry must address these questions before further bankrupting itself to provide more data to planners and spending thousands of dollars per acre to create land that when reclaimed is worth only a few hundred dollars per acre. ? Reply by R.V. Ramani and R.J. Sweigard We thank Mr. Learning for his valuable contribution. His views on the problems of land use planning and mineral resources are most welcome additions to our paper. As the title indicates, our paper was more concerned with the impacts of land use planning on mineral resource conservation than with the details of the planning process. On the whole, his five recommendations would be helpful for mineral resource conservation. However, we would suggest that the argument he presents for his final recommendation does not address the differences between mining as a land use and commercial or institutional uses. We believe that this difference is the crux of the issue. We share Mr. Learning's desire to ameliorate the adverse impacts of land use planning. Possibly the most detrimental impact is the loss of mineral resources. Any development, whether mineral or community, that does not give proper consideration to other resources can result in permanent loss or sterilization of resources. With proper planning, some of these losses can be avoided. As our paper indicated, one factor that limits the consideration of mineral resources, and ultimately leads to their sterilization, is the generally inadequate levels of resource characterization and understanding of the unique nature of mineral resources and mining operations. The last point raised by Mr. Learning is also important. In terms of reclamation and land use planning in mining districts, we certainly do not advocate spending more than what the results are worth. The main thrust of the paper was to explore the avenues for conserving the mineral resources so that, at some appropriate time, the issue of mining and reclamation can still be addressed. ?

Jan 1, 1986

By Harold M. Mooney

WHEN apparent resistivity data are taken with the symmetrical Wenner 4-electrode spread, a fixed center position is used and readings are taken for values of electrode separation. Basic data consist of apparent resistivity plotted against separation of adjacent electrodes . The interpreter attempts to infer geologic structure, such as the depth to discontinuities and the nature of subsurface earth materials. An earlier paper' described methods for interpreting resistivity data. All of these involve a severe assumption, namely that the earth in the region of interest consists of horizontal layers, electrically homogeneous and isotropic. The actual earth never satisfies this assumption exactly and may deviate from it so much that none of the above methods can be applied. Attempts in three directions have been made to modify the assumption so that it approaches known geologic complexity more closely. First, curves have been calculated for dipping discontinuities. Stern' and Aldredge hose a few widely separated dip angles. Trudu confined his attention to small dips. Berel'kovskiy and Zubanov computed gradient curves for widely separated dip angles. Unz as given the most complete solution, with a brief attempt to treat the three-layer case. Second, anisotropy can be taken into account. It seems geologically probable that layered materials have different vertical and horizontal conductivities. Cagniard, Maillet, and Pirson et up methods for finding an equivalent hypothetical isotropic medium. Standard interpretation methods can be applied to this, and the actual medium can then be deduced. Belluigi'" discounts the practical importance of anisotropy; Geneslay and Rouget do not agree with his conclusion. Third, the effect of variable resistivity in a layer can be considered. Keck and Colby" examine the mathematics of an exponential increase in a surface layer. Several authors, for example, Stevenson,'' consider a continuous variation of resistivity with depth. The present paper deals with a linear variation of resistivity in a surface layer. Geologically, surface variations should be expected. Unconsolidated materials such as glacial drift show marked irregularities over short distances. The effects of weathering change with depth. The moisture content of material above the water table may vary from a dry sand to a saturated clay, and both of these will be changed by rainfall. Figs. 1 to 6 present apparent resistivity curves to show the effect of a variable surface layer. In all cases resistivity varies linearly with depth down to a depth of one unit. Material beneath this depth has constant resistivity. Electrode separation is plotted in depth units. Insets on each figure show the corresponding cross-sections, plotting true resistivity against depth. To illustrate, consider curve A of Fig. 1. The true resistivity of material at the surface of the earth is taken as 0.4 units. Resistivity increases with depth, reaching a value of 1.0 at 0.5 depth units and 1.6 at 1.0 depth units. Below a depth of 1.0, all the material has very low resistivity (zero, for purposes of calculation). Curve A in the main part of Fig. 1 shows how apparent resistivity varies for this case as the electrode spacing is increased. To illustrate further, curve E of Fig. 4 corresponds to true resistivity of 1.2 units at the surface, 1.0 at a depth of 0.5 units, 0.8 at a depth of 1.0, and 1.5 for all depths greater than 1.0. Apparent resistivity curves have been plotted logarithmically so that the shape of the curves becomes independent of the units, giving the curves wide validity. A certain drift-covered area, for example, shows a gradual decrease of resistivity from 230 ohm-meters at the surface to 150 ohm-meters at the bedrock surface, 275 ft down; bedrock resistivity is 800 ohm-meters. Curve E of Fig. 5 indicates that true resistivity decreases from 1.2 units at the surface to 0.8 at a depth of 1.0, then increases abruptly to a constant value of 4.0 units. Since resistivity and depth ratios are the same, this can be used to predict the field curve. For Fig. 5, multiply true resistivity and apparent resistivity by

Jan 1, 1955

By W. M. Myers

MINERAL Economics is the most recent profession to be recognized as a separate division of the mineral industries. It has originated from the increasing awareness of the importance of the economic aspects of industries concerned with discovery, extraction, and utilization of minerals. It is concerned with the interrelated fields of economics and technology. The individual trained in economics alone cannot qualify. The curriculum in the School of Mineral Industries at The Pennsylvania State College was approved in May 1946, and enrollment begun in September of that year. Due to the transfer of advanced students from other courses, particularly metallurgy and electrical engineering, it was possible to graduate the first seniors in June 1947. The next class was graduated in February 1948. From experience derived from placing these graduates in industry, and from information supplied by prospective employers, valuable data have been obtained in the organization and operation of the course of study.

Jan 1, 1948

By William H. Emmons

CONTENTS. [ ]

Jan 1, 1913

By Alexander Gakner

Since the end of World War II the Soviet Union has made great strides toward economic development of the country. Today it is firmly established as the world's second largest industrial power after the United States and it has committed itself before the people on both sides of the Iron Curtain to catch up with and to overtake us within a few decades. No nation could achieve such a degree of industrialization or aspire to become the world's industrial leader without a large supply of many basic mineral raw materials or at least easy access to such resources. In addition, it requires technical competence, a large skilled labor force, and a high rate of capital investment. Why should we concern ourselves with these Soviet aspirations? The Free World's yardstick of measuring a nation's well-being is the standard of living of the people in that country. Presumably even Communist governments are committed to some, however gradual, improvement in the standard of living of their people. The population of the USSR is 20 pct greater than that of the United States. Hence, if they ever achieve a standard of living equal to ours, they must by all logic reach a greater overall industrial output. However, in the U.S.S.R. the standard of living of the masses has not kept pace with the expanding industrial production and is still far behind that of the United States. Our concern, therefore, is with what the USSR intends to accomplish with its expanding industrial power: Will they produce large mineral raw-material surpluses and manufacture products to compete with us for world markets and attempt to put us out of business if not use it directly to wage war; or will they use their resources merely to produce more consumer goods for the Soviet people; or will they, along with other Communist nations in the not-too-distant future, compete with us for the world's sources of mineral raw-materials to maintain a high level of mass consumption?

Jan 6, 1960

By Ashok K. Sinha

During the course of an in~*estigation into the occurrence of ordered AB3 structures, the following new phases have been found —CrRh3 (AuCu3 type), CrCo3 (MgCd3 type), HfCo4 (Ths Mn23 type), and WPt, MoPh type). The composition of the TiPt3-x phase (TiNi, type) is close to Ti23Pl77. The alloy chenzistry of transition rnetal AB3 structures is rezliewed in the light of electron concentration correlations of hex-agonality recently obtained for quasi-binary alloys. The relatizte colurne contraction in the AB3 structures increases with increasing difference in volume of the conzponents. A family of ordered close-packed layered structures is formed by stacking identical layers of composition AB, in various sequences, such that the coordination is twelvefold throughout and there are no A-A contacts. Previous work' on quasi-binary AB3 alloys has led to the conclusion that the stacking sequence of the AB, structures changes with increasing radius ratio RA/RB from a purely cubic, through different mixtures of hexagonal and cubic stacking to a purely hexagonal stacking. However. for binary AB3 alloys, a correlation between the type of the crystal structure and the position of the components in the various volumns of the periodic table has been noted.2-5 It has been noted6 that this correlation appears to hold even though the radius ratio RA/RB may vary over a considerable range with the location of the components in the three long periods. Another study7" of several quasi-binary systems led to the conclusion that an increase in hexagonality of the stacking is associated with increase in the electron concentration e/a. as defined by the average per atom of the total number of electrons outside the inert gas shells. In apparent conflict with this conclusion, it is known that seven binary alloy structures isotypic with TiNi3 which is 50 pct hexagonal occur at a higher electron concentration (e/n = 8.5) than that (e/a = 8.25) for the 100 pct hexagonal MgCd3 type structure present in seven binary AB3 alloys. Table 111. In the present work, an investigation into the occurrence of binary AB3 structures in transition metal alloys was made, and a survey of binary AB3 structures is presented. EXPERIMENTAL The starting materials were pure metals of 99.9 wt pct purity. The alloys were arc-melted under partial pressure of argon and annealed in sealed silica capsules lined with molybdenum foil under argon at- mosphere. The total weight loss upon melting and subsequent annealing was always less than 1 pct and hence the alloys will be referred to by their intended (unanalyzed) compositions. Wherever the constitution permitted. the alloys were given a homogenizing treatment at 1200°C (3 days) prior to annealing. Unless otherwise stated all alloys were annealed at 900°C for 1 week and water-quenched. Sometimes the final annealing treatment was carried out on powders to accelerate the attainment of equilibrium. X-ray powder patterns were taken using a Guinier-de Wolff focusing camera (CuK, radiation) or an asymmetrical focusing camera (Co or CrK, radiation). For lattice parameter determination. internal silicon standards were employed. The intensity calculations were made using a Fortran IV program written by Jeitschko and parthe.9 RESULTS Twenty AB3 and three AB4 alloys were investigated. Table I lists the crystallographic data on some of the intermediate phases encountered in the present work. Table II contains the X-ray data for HfCo, (Th,,Mn,, type). The positional parameter, x. was assumed to be 0.378. the value for Th6Mnn2310 The X-ray pattern of ZrCo, was very similar to that of HfCo, and the previous structure determination of ZrCo, by Kuzma el al." was confirmed. Ordering in the alloy CrCo could be ascertained by the presence of only one weak super lattice line (101). the others being too weak presumably owing to the small difference in the scattering powers of chromium and cobalt. This line was observed in the X-ray pattern of powder from the massive sample annealed at 830°C (7 days) after the powder had been reannealed at 600°C (24 hr). The diffraction pattern of the powder similarly reannealed at 830°C (24 hr) contained only the lines due to a mixture of hcp and fcc Co(Crj solid solutions. Therefore, it appears reasonable to assume that O2 and/or N2 contamination which would be less likely to occur during the 600°C anneal was not responsible for the observed weak reflection. Also. this reflection cannot be identified with any of the strong lines of the neighboring s phase which is present in the Co-Cr system at higher chromium contents. The composition corresponding to the TiNi3 structure observed by Raman et al.12 in the two-phase alloy Ti,zt,, has been established in the present work as being between There was satisfactory agreement for the low-angle lines (up to d = 1.997A) between the observed diffraction pattern of TiCua and that calculated assuming the ZrAu, structure. as recently proposed by Pfeifer-et a1.I3 However. some of the superlattice lines. e.g., at d = 1.937 and 1.919A. predicted by the ZrAu, structure were not actually observed eve? though neighboring lines. at d = 1.947 and 1.986A. of comparable calculated intensity were present. The ZrAu

Jan 1, 1970

By Elton A. Youngberg

J. H. HEARDING, Jr.*—Extremely hard ferruginous chert (taconite) was encountered in driving a drift at the Fraser underground mine near Chisholm, Minn., on the Mesabi Iron Range. In order to get better results in drilling in this ground, it was decided to try tungsten carbide bits. In the beginning, 1½ in. tungsten carbide bits and 1 1/8 in. round-lugged alloy steel drill rods with "jack-stud" inserts were used. Considerable difficulty was encountered because the jack-stud became loose in the drill rods. Because there was not enough alloy steel drill rod on hand, we began to insert jack-studs in the ordinary high carbon drill rods and found, to our surprise, that there was less trouble with jack-studs working loose in these rods than there had been with the alloy steel rods. As a result, use of the alloy steel rods has been discontinued entirely. Under the heading "Drilling Procedures" the statement is made that all holes are started with detachable bits or conventional steel to prevent undue strain on the tungsten carbide bit inserts when collaring a hole on uneven ground. This practice was followed in our work originally for the same reason. It was soon found, however, that the holes could be started with the tungsten carbide without injuring the inserts if the drill operator was careful and did not give the drill too much air until the bit had a chance to seat itself in the rock. J. C. FRANZ*—In a discussion of other technical papers with reference to percussion drills and the use of carbide tungsten bits, it was my impression that the authors reported one of the first difficulties experienced with the use of standard, conventional percussion drills, was insert bit failures due to crushing of the bit inserts when the bits became dull. During the past few years, some of the rock drill manufacturers, I am told, have adopted an air drill for use with the carbide bits that have a lighter blow and faster rotation than the regular machine. This machine has been tested and the carbide bit failures have been considerably reduced. L. W. DUPUY†—The difficulties Mr. Youngberg mentions that were had with rod and coupling breakage call to mind similar troubles experienced at the Picacho mine in California near Yuma.6 The commercial couplings then available were found to be tempered almost to brittleness. Rod breakage was usually in the threads near the end of the rod. The highly-tempered couplings would break as soon as the rod broke. The solution was to thoroughly anneal the couplings and to put in only a very mild temper. Subsequently the alloy used in making the couplings was changed from the original by the manufacturer, but still only a very mild temper was used. The result was that the softer coupling would give but would not snap and release its hold on the broken rod thread. Fishing jobs were reduced to the few where the rods broke at the rod end of the thread. Thread breakage on the rods was further reduced by thorough annealing prior to tempering. The data Mr. Youngberg presents regarding the use of carbide inserts on long blasthole drilling is most interesting and it would appear that the use in this manner of percussion drills and carbide bits will have many applications. W. M. WOODWARD*—How many feet of hole, on the average, do you get from a tungsten carbide bit, and is there much variation from this average? E. A. YOUNGBERG (author's reply) —In recent months the 2 in. tungsten carbide bit footages in long hole drilling hake varied from 115 .to 140 ft monthly. The footages obtained from individual bits vary from several feet to over 300 ft, however the life of a majority of the bits will be within 25 ft of the average.

Jan 1, 1950

By G. W. Crane

When ore was discovered on the Tintic Standard property in the spring of 1916, new developments were immediately started both north and south of that property, on the supposition that in East Tintic the ore would be found to occur in northerly trending channels, similar to those so characteristic of the older camp. But 9 years of developments have failed to establish the existence of such a channel. This is due undoubtedly to important differences in the geology of the two camps, that were not recognized, and is indicative of the danger in the general tendency toward interpreting the geology of East Tintic too strictly in terms of that of the older camp. It should not be forgotten that while the two sections have had practically the same geological history, the net results of a long series of geologic processes have developed in them conditions that differ so widely and in so many particulars that the necessity of regarding them as essentially different districts seems apparent. In an effort to emphasize this fact, this paper is devoted chiefly to a comparison of the geological conditions as found in the two camps and is addressed more particularly to those familiar with the geology of the Tintic district. Following a short description of the several ore discoveries and of the Tintic Standard mine is a brief discussion of the evidence of ore channels in East Tintic. For my information regarding the Tintic Standard mine, I am indebted to the courtesy and generous assistance of Messrs. Wade and Snow of the Tintic Standard Mining Co. East Tintic District The Term East Tintic district is here used to represent that eastern part of the Tintic mining district lying between the productive portion of the old camp of Tintic on the west, the foot hills of Goshen Slope, on the east, the Denver and Rio Grande Railroad on the north, and Silver Pass on the south, all in Utah County. As represented by the geological map, Fig. 1, it includes an area about 4 miles wide, east and west, and 5 miles long, north and south, within which the Tintic Standard mine is about centrally located. The map is a compilation of data supplied, for the most part, by the Chief Consolidated Mining Co. and represents the

Jan 1, 1927