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By N. K. Chen, C. H. Mathewson

Single crystals of high purity aluminum of various orientations were carefully documented after plastic extension. Special attention was given to the formation of slip lines, deformation bands, and asterism. An explanation for the geometry and mechanism of formation of deformation bands is considered. WHILE the general process of plastic extension of face-centered cubic metals is well understood,' the accompanying structural changes due to slip and rotation are far more complex than ordinarily assumed. In the case of stretched single crystals of aluminum, the complicated behavior is especially marked by the formation of deformation bands, as first indicated by Collins and Mathewson." Such bands were believed by them and also by others,".'7 who have discussed banded structure in general, to represent one of the important modes of lattice reorientation and to be intimately connected with the recrystallization process. Yet, despite their fundamental importance to the understanding of the mechanism df both plastic deformation and recrystallization, practically no study of the crystallographic features of these bands in their relationship to the conventional slip process has been attempted. This paper describes part of an extensive investigation on the structural behavior during plastic deformation of aluminum single crystals and is especially concerned with the characteristics of deformation bands. The investigation of the subsequent re-crystallization of deformed aluminum single crystals will be discussed in a later publication. Experimental Procedure Single crystal specimens of 99.996+ pct pure aluminum, Yz in. in diam and 5 to 6 in. in length were made both by the Bridgman method5 nd by a modified temperature gradient method.'* Crystals were selected in which the lineage deviation did not exceed 2"; i.e., as determined from the back-reflection Laue X-ray photograms. These crystals were radiographed to insure that no internal porosity was present. The orientations showed good coverage of the whole area of the Taylor and Elam triangle.' Orientations of the crystals were obtained by the back-reflection Laue technique described by Greninger." Crystals so selected were tapered very carefully in a lathe to obtain a linear decrease in diameter from 0.500 to 0.350 in. along a gage length of 3 in. This is considered desirable because it permits a strain gradient to be introduced in a single specimen at one initial orientation. The advantages of tapered crystals for studying the development of slip lines and recrystallized grains have been pointed out by previous investigators." The cold-worked layer resulting from the machining operation was removed by alternate etching in aqua regia and careful polishing with 2/0 emery paper until undistorted Laue back-reflection spots were obtained. A homogenization treatment at 600 °C for 24 hr was then introduced to insure the removal of residual stress. Two of the crystals so prepared were also checked by use of a glancing angle technique. Using a copper target, at 30 kv and 10 microamperes, a monochromatic beam was positioned at right angles to the axis of the crystal about which it rotated. The time of exposure was 24 hr. From these X-ray photograms, it was concluded that the present method of preparation of single crystals is satisfactory. Following this procedure, the crystals were elec-trolytically polished in a 2:l solution of methyl alcohol and concentrated nitric acid. Intermittent

Jan 1, 1952

By K. Huessener

INTRODUCTION THIS paper attempts a survey of the principles involved in the com¬bustion of blast-furnace gas in boilers and stoves. I do not expect to be able to give much information which is actually new, since the laws and methods of calculation pertaining to this problem are contained in a number of handbooks; but, so far as I am aware, they have nowhere been treated exclusively with reference to this one problem of gas economy. The road which I follow is less that of strictly scientific research than that of the practical engineer, faced by operation problems which require a. quick solution by easily accessible means without a prolonged search in scientific handbooks. For this purpose I give a number of tables and diagrams, as well as the results of many years' practical working experience as combustion engineer, which I trust will prove useful to my readers. HISTORICAL Considering the tremendous efforts made during the last 15 years to increase the efficiency of all kinds of power plants, it is highly surprising that until a comparatively very recent period, progress in the economical combustion of blast-furnace gas has been so slow. The explanation generally put forth, that fuel has been so cheap that it was hardly worth while to bother about this economy, will not hold good, for the greatest trouble was taken to improve the combustion of coal and to reduce the consumption of steam. The most plausible explanation appears to be the general impression, held as an accepted fact, that gas, especially hot, uncleaned, blast-furnace gas, was not a good boiler fuel. Many managers of high repute had tried unsuccessfully to improve the conditions of its use, and the dictum went forth that efficiencies of over 60 per cent., particularly with high loads, were impossible. This was the situation not only in the United States, with very cheap fuel, but also in Europe, where fuel prices are twice and three times as high.

Jan 2, 1916

By E. C. Carris

The loading of bituminous coal mechanically was recognized about the year 1900, but during the following 28 years less than 5 per cent of the bituminous production in the United States was loaded by mechanical means. During the past 16 years, however, the usage of some form of mechanical loader has had a very rapid and accelerated growth, until at present production of bituminous coal by mechanical means has reached an all-time high of approximately 46 per cent, and is still increasing. This rapid growth in the use of the mechanical loader has been supplemented by an increase. in mechanical cleaning. The importance of mechanical cleaning of coal was recogniaed many years before the mechanical loader was introduced. because of the impossibility of cleaning manually the sizes below 2 in.. and the increasing competition from other fuels. Utilization of mechanical loaders without nleclianical cleaning 011 the surface for at least one or more sizes is the exception, rather than the rule. One exception is a mine that employs caterpillar-mounted mobile loaders exclusively, and mines the entire seam without any selectivity, and yet loads and ships six grades of coal of the very highest quality without mechanical cleaning. Such a fortunate situation can exist only where mining conditions are ideal, where top and bottom are exceptional and there are no impurity partings, and where there is loader height. The conversion from hand loading to mechanical loading has definitely introduced many problems in the preparation plant of yesterday and in the modern streamline plant as well. Many of these problenis have been solved by good, sound, conscientious initiative on the part of the plant personnel, with minor expenditures; the solution taking the pattern of rearranging 2nd improving the equipment at hand. Other problems have caused, and are causing, considerable concern and difficulty. Large Impurities The removal of large quantities of large impurities from the lump coal, and their handling and disposal, is definitely a troublesome and costly problem. The cost of manually removing the impurities from the picking table alone, based on the actual recovered lump coal, can reach a cost of 42 cents per ton or more. In the design of future plants it would be wise to give this phase of preparation considerably more time and thought, particularly if the seam of coal contains one or more heavy partings and the mining procedure is all seam. This same caution applies to seams that may not contain heavy partings but have poor and heavy draw-slate top, which falls with the coal during the mining cycle. One of the more recent of the modern preparation plants has answered this problem by installing a rock crusher under the picking table in such a manner that the impurities can be diverted by gravity directly to the crusher. This reduces the

Jan 1, 1947

By E. C. Carris

The loading of bituminous coal mechanically was recognized about the year 1900, but during the following 28 years less than 5 per cent of the bituminous production in the United States was loaded by mechanical means. During the past 16 years, however, the usage of some form of mechanical loader has had a very rapid and accelerated growth, until at present production of bituminous coal by mechanical means has reached an all-time high of approximately 46 per cent, and is still increasing. This rapid growth in the use of the mechanical loader has been supplemented by an increase. in mechanical cleaning. The importance of mechanical cleaning of coal was recogniaed many years before the mechanical loader was introduced. because of the impossibility of cleaning manually the sizes below 2 in.. and the increasing competition from other fuels. Utilization of mechanical loaders without nleclianical cleaning 011 the surface for at least one or more sizes is the exception, rather than the rule. One exception is a mine that employs caterpillar-mounted mobile loaders exclusively, and mines the entire seam without any selectivity, and yet loads and ships six grades of coal of the very highest quality without mechanical cleaning. Such a fortunate situation can exist only where mining conditions are ideal, where top and bottom are exceptional and there are no impurity partings, and where there is loader height. The conversion from hand loading to mechanical loading has definitely introduced many problems in the preparation plant of yesterday and in the modern streamline plant as well. Many of these problenis have been solved by good, sound, conscientious initiative on the part of the plant personnel, with minor expenditures; the solution taking the pattern of rearranging 2nd improving the equipment at hand. Other problems have caused, and are causing, considerable concern and difficulty. Large Impurities The removal of large quantities of large impurities from the lump coal, and their handling and disposal, is definitely a troublesome and costly problem. The cost of manually removing the impurities from the picking table alone, based on the actual recovered lump coal, can reach a cost of 42 cents per ton or more. In the design of future plants it would be wise to give this phase of preparation considerably more time and thought, particularly if the seam of coal contains one or more heavy partings and the mining procedure is all seam. This same caution applies to seams that may not contain heavy partings but have poor and heavy draw-slate top, which falls with the coal during the mining cycle. One of the more recent of the modern preparation plants has answered this problem by installing a rock crusher under the picking table in such a manner that the impurities can be diverted by gravity directly to the crusher. This reduces the

Jan 1, 1947

By Charles R. Cavanaugh, John F. Elliott

The activity of nickel in liquid Pb-iVi alloys which are rich in lead was measured in the temperature region of 700° to 1100°C by means of the galvanic cell: The electrolyte used was stabilized zirconia. Tlze data were correlated using the a function, and a plot of the temperature coefficient aE/aT All subsequent calculations of the thermodynamic properties are based on these two functions. The activity, activity coefficient, and molar properties of mixing of nickel are reported. Nicke1 shows extreme positive deviations frorn ideality while lead shows a very slight positive deviation in the composition range studied The study of the activity of nickel in liquid Pb-Ni alloys reported herein was undertaken to explore the use of stabilized zirconia, an oxygen-ion electrolyte, with liquid-metal electrodes, and to obtain further information on the thermodynamic properties of the liquid binary Pb-Ni system. The cell The reversible electromotive force of the cell results from the difference in the chemical potential of the oxygen at the two electrodes: po, (left) - p~ (right) = -4E5 [I] The chemical potential of oxygen on the right is fixed by the activity of nickel in the solution and pure solid nickel oxide. That on the left is set by pure solid nickel in equilibrium with pure solid NiO. By definition: Since the chemical potential of nickel is related to the chemical potential of oxygen through the equilibrium constant for the formation of NiO from nickel and oxygen gas, the electromotive force of the cell is also expressed In this case, n is 2, E is the reversible potential of the cell, and 5 is Faraday's constant. The work of Kuikkola and wagnerl and Schmalz-reid2 has shown that the stabilized zirconia electrolyte is essentially an ionic conductor at the oxygen levels encountered in the experimental arrangement of the work, i .e., PG > 10-l7 atm. THE EXPERIMENTS The advantage of this type of reversible cell over those using a liquid electrolyte is the simplicity arising because the electrolyte also functions as one of the containing crucibles. A further simplification was the choice of the Ni (sat.)-NiO electrode as the standard. This permitted a ready check on the behavior of the electrolyte, as the potential of the cell must become zero when the right electrode becomes saturated with nickel, either because of a change of temperature or because of the addition of nickel to the electrode. It also permitted the potentials being measured to lie in the most satisfactory experimental range of 0 to 100 mv. Although it was not theoretically necessary, lead was included in the standard electrode as it assured good contact between the electrode and electrolyte. Cell Design. The general arrangement of the experimental cell assembly is shown in Fig. l(a) and the details of the cell itself are contained in Fig. l(b). The anode lead wire on the interior of the cell was connected to a coil of perforated sheet nickel. Within this coil were nickel oxide pellets which were held beneath the surface of the liquid Pb-Ni alloy. A disc of nickel oxide was held at the bottom of the external crucible (alumina) by means of the thermocouple protection tube. The nickel oxide disc and pellets were compressed dry at 10,000 psi and sintered at approximately 1000°C for an hour in air. A major experimental difficulty of reversible electromotive force cells with liquid electrodes is the selection of suitable materials for connecting

Jan 1, 1964

By G. S. Cole, G. F. Bolling

ThE exact type of fluid flow which occurs in a solidifying ingot is important in determining subsequent grain structure. This has been shown in studies of natural Convection" and of forced stirring or other disturbances of the melt."16 We shall explicitly argue that a complement to the existing natural flow in an ingot should be more effective than other types of flow in promoting the columnar-to-equiaxed transition. The ultimate effects of fluid flow upon structure is one of the topics of solidification that we have investigated in the alloy system Pb-Sb, under conditions simulating casting. In Fig. 1, the essential features of a bidirectional growth apparatus are shown; horizontal freezing from water-cooled faces within a low-thermal-conductivity lavite boat is a reasonable simulation of an ingot section. Details such as the furnace and thermocouples are omitted in order to show the location of four permanent. magnets, each with a pole separation of 21 in. providing a central field of about 1000 Gauss. When coupled with a dc current imposed through appropriate connections made at the cooled faces, a flow of fluid is produced as shown schematically. This technique described by Pfann and ~orsi" is ideal for our purpose since the flow indicated is the same as that we observe to occur naturally in this system. Components of 99.999 pct purity were used for study and all due precautions were taken in alloy preparation to avoid contaminants. Sections of the specimens were taken to ensure results representative of the interior as well as the surface of specimens. All proportions of equiaxed and columnar regions were measured by tracing the etched grain structures onto graph paper and simply counting squares. Four alloys were examined at superheats of 40" * 5°C and 100" * 9°C. Preliminary tests had shown that no appreciable enhancement of structure was obtained with magnetic field alone, so that this condition is not reported; it should nevertheless be noted that other configurations of magnetic field will reduce convection and thus enhance columnar growth.'8 For the tests reported the magnetic field was applied to a specimen by bringing the four preassembled magnets to a position 2 mm from an outer tube immediately after the ingot was poured. The dc current of 30 amps passed through the sample throughout the entire solidification cycle, resulting in a power dissipation of 9 w per sq cm of interface. This may be compared to the evolution of latent heat of approximately 18 w per sq cm. Table I contains the results of this experiment in terms of the total area ratio, equiaxed/columnar grains, as a function of the field interactions, solute concentrations, and superheats employed. The total structure of the ingot is seen to be most influenced when both the field and current are applied simultaneously; when current acts separately, little effect may be noted in spite of the heat supplied. In addition, the change in structure from the no field-no current case to the field-current condition is more pronounced at the higher superheat, and the higher the concentration of antimony. An example of the grain refinement, as well as the increased equiaxed zone, is shown in Fig. 2. It is now important to prove that there is indeed an increase in fluid flow due to the presence of the field-current interaction; this is done by temperature measurements in the liquid metal. Let us consider a bidirectional casting in which heat is applied to and removed from the system, in such a way that rate of solidification is zero.* When a sensitive thermocouple

Jan 1, 1967

By W. T. Stuart

THE increased demand for iron ore has necessitated a re-examination of ore-bearing lands on which the presence of water previously has indicated hazardous and expensive operating conditions. In view of the importance of iron ore production to the national economy and defense, the Ground Water Branch of the U. S. Geological Survey, in cooperation with the state of Michigan, began a study of mine drainage in the Iron River district in 1945, and later extended the work to the Marquette district. The purpose of these studies was to define the principles involved in the movement of surface and ground water toward the mined areas, with the hope that the information obtained in the research would lead to the development of methods of water control and to a reduction in the total mining costs. Not only are the direct costs of drainage increasing, but also the indirect operational costs of working a wet mine are becoming a larger proportion of the total mining costs. For some wet mines the direct costs of pumping and drainage may range from 35 to 40Ø per ton of ore produced, but the indirect costs due to handling wet ore and controlling the water may be five to ten times this amount. The methods of study were formulated as the work progressed, and inasmuch as they were the first large-scale studies of their kind, they should serve as a guide for the solution of similar problems in other mining areas. The Iron River district was chosen for a pilot study because in this district the longest records of mine pumpage and water-level observations were available, including, as they do, the records for the Homer mine of the M. A. Hanna Co., where pumping from surface wells began in 1930. The results of the first investigation by the Michigan Department of Conservation have already appeared." The first section of the report on a similar study of the Marquette district, which was started in 1948, will be published this year. Methods of Study In an effort to reduce the flow of water into the mine workings in the Iron River district, about 4500 gpm was pumped from the bedrock being mined and about 9000 gpm from the glacial overburden. In the Marquette district in the vicinity of Ishpeming and Negaunee, about 5000 gprn was pumped from the bedrock and about 4000 gpm was pumped from the glacial overburden. Where the water was pumped only from the bedrock, the rate of pumping ranged from a few hundred gallons per minute in the dry mines to many hundred gallons per minute in the wet mines. In each district, pumping from the overburden was localized on a few properties where costly pumping installations had been made and the expenditures for power had been large. In each district a comprehensive ground-water investigation was made of the whole area, involving the collection and interpretation of all the available data bearing on the source and quantity of water to be controlled. Although it is not the purpose of this paper to discuss the methods of making a ground-water investigation, it should be pointed out that a drainage study follows a pattern of engineering analysis that determines the occurrence, source, movement, disposal, and quantities of water involved. The investigation in the iron-mining districts of Michigan began with the construction of a map of the buried bedrock topography. Because the ground-water reservoirs occupy the low points in the bedrock basins, this map gives information concerning their areal extent, depth, shape, and degree of interconnection. The depth to water in the drillholes and wells indicates the altitude to which the ground-water reservoirs are filled, and the logs of the material penetrated in the drillholes and wells indicate the general character of the materials filling the reservoir. The slope of the ground-water surface indicates the direction of flow through the reservoir, the water movement being from the points of higher altitude to points of lower altitude. By analysis of the rise and fall of the ground-water levels in response to additions of water through recharge and to changes in the rate of discharge through pumped wells, estimates of the total quantity of water in storage and of the rate of flow through the reservoir

Jan 1, 1952

By A. E. Dwight, P. A. Beck

A search was made for ordered phases of AB3 composition in various combinations of Ti- and V-group elements with CO-and Ni-group elements. Three new TiNi3-type phases ZrPd3, HfPd3, and HfPt3 were found. In addition, twelve new Cu3Au-type phases TiRh3, Tilr3, ZrRh3, Zrlr3, HfRh3, Hflr3, VRh3, VIr3, CbRh3, Cblr3, TaRh3, and TaIr3 were also found. The lattice contraction for all three structures considered increases with increasing relative size of the A atom, suggesting that it is mostly the A atom that cont~acts. It was noted that, for the same radius ratio the lattice contraction is larger when the A atom is Ti than if it is Cb OY Ta. It is well known that elements or disordered solid solutions, which have structures with spherical close-packing, may be described in terms of various stacking schemes of close-packed layers. Stacking of the type abab corresponds to the hexagonal close-packed structure, and stacking of the type abcabc corresponds to the face-centered-cubic structure. In binary alloys of the first, second, and third long period transition elements various AB3 phases occur with close-packed ordered structures. It was observed that these ordered structures also may be described by suitable stacking of close-packed ordered layers, Fig. 1, as first shown by Laves and Wallbaum for TiNi3.' It is clear that the units of translation in such a close-packed layer consist of four atoms, one of which (black circle) is atom A and the three others (empty circles) are atoms B. Because of the alternation of A and B atoms in every second row of each layer, the unit-cell dimension in the layer is equal to the sum of the diameters of atoms A and B: a0 = 2(rA + rB). Stacking of such layers in the sequence abab results in a hexagonal close-packed structure of the MgCd, type. The unit-cell dimension in the basal plane is approximately double of that for the disordered hexagonal close-packed structure, but in the direction of the hexagonal axis it is about the same, so that 2co/uo = 1.63 in case of spherical close-packing. Ordered hexagonal close-packed structures of this type were found to occur in MoCo3,2 WCo3,, and UPt, .4 When the ordered layers shown in Fig. 1 are stacked according to the scheme abcabc, the resulting ordered structure is of the AuCu, type (cubic). Structures of this type were found to occur in TiPt3,5 CrPt,,' CrIr,,' and URu, .4 Finally, the stacking scheme abacabac of the same ordered layers results in a hexagonal close-packed structure of the TiNi3 type.' In this case, the unit-cell dimension is doubled not only in the basal plane, but also in the direction of the hexagonal axis, so that co/ao = 1.63. Structures of this type were found to occur also in TiPd3,5 ZrPt,," and UPd,.4

Jan 1, 1960

By Sidney Diamond, Charles Wert

The anelastic behavior of Ni-C alloys of nominal 0.5 wt pct C has been determined over a wide temperature range. The most prominent damping effect, that due to the presence of C-C pairs, was measured both above and below the Curie temperature. The effect on diffusion of the C-C pairs by magnetic spin ordering is deduced to be very small. The diffusion coefficient for C-C pairs in nickel is given by the expression ThE solid-state diffusion of both interstitial and sub-stitutional solutes in ferromagnetic solvents has been the subject of a number of investigations. Measurements of the self-diffusion of iron,"' the diffusion of nickel1,4 gold,"1 and cobalt4 into iron, the diffusion of vanadium in an Fe-V alloy,' and the diffusion of cobalt and nickel in Co-Ni alloys9 show an unusual behavior. In both the ferromagnetic and paramagnetic regions, far removed from the Curie temperature, the diffusion coefficient, D, obeys an Arrhenius relation. However, in the ferromagnetic region D is markedly lower than would be expected from an extrapolation of D from the paramagnetic region; this results in an increase in the activation energy in the ferromagnetic region. The cause of this effect for self- and substitutional diffusion is uncertain. Since substitutional diffusion is presumed to proceed by the vacancy mechanism, it has been variously suggested that the increase in activation energy below the Curie temperature is due to one of the following causes: 1) an increase in the energy of formation of a vacancy because of local demagnetization around the vacancy,2,3 2) a decrease in vacancy mobility in the ferromagnetic state,' or 3) an effect on the entropy of motion of a vacancy in the ferromagnetic state.5 Quite another explanation for the observed effect has been proposed by Borg.7 The diffusion coefficient is a function of the elastic constants of a metal. Since the temperature dependence of the elastic constants often changes at the Curie temperature, the temperature dependence of D might be expected to undergo a universal change in the vicinity of the Curie temperature. The magnitude of the change in D would, of course, depend on the magnitude of the change in the elastic constants. One might attempt to differentiate between vacancy effects and elastic effects by making measurements on interstitial alloys, in which vacancy effects play no role. Some measurements of this type have been made; this paper reports additional observations. Measurements of the diffusion of carbon in a Fe by a tracer technique8 and of the diffusion of carbon in a Co and in Co-Fe alloys by a decarburization method9 reveal a small effect, if any, on D of the magnetic change at the Curie temperature. If the effect of spin ordering is only to alter the parameters controlling formation or mobility of a vacancy, interstitial diffusion should indeed remain unchanged through the magnetic transition, as these measurements imply.

Jan 1, 1968

By G. R. Speich

A cellular precipitation reaction in which cells consisting of an Ni3Ti (DO24) phase and austenite are formed has been studied in an austenitic Fe-30 Ni-6 Ti alloy. The variation of the growth rate and interlamellar spacing of the Ni3Ti cells with temperature has been determined m the range 400" to 975°C; the interlamellar spacing is proportional to the degree of undercooling; the growth rate can be expressed by an equation of the form G = K?T)2 exp(-Q/RT). The habit of the Ni3Ti lamellae is (001)Ni3Ti (111)y;[010]Ni3T2 [010]y. An almost perfectly coherent interface is formed between Ni3Ti lamellae with this orientation rela -tionship and the intervening austenite. This first Ni3Ti cellular product is subsequently consumed by a second cellular reaction of much coarser spacing. CELLULAR precipitation reactions have been studied in copper-base,1,2 Au-Ni,3 pb-sn,4 and iron-base ferritic5,6 solid solutions, and this mode of precipitation has been treated theoretically by smith," Turnbull,8,9 cahn,10 and more recently by bohm.11 In the case of substitutional austenitic iron-base alloys little or no data are available, Cellular precipitation reactions are well known in austenitic nickel-base alloys12,13 but usually these reactions do not proceed to completion because of general precipitation occurring in the matrix, and they have not been studied in detail. Precipitation from an austenitic Fe-30 Ni-6 Ti alloy was studied as part of a larger investigation of the mechanisms of precipitation from substitutional iron-base alloys. This alloy, austenitic at high temperatures, decomposes at lower temperatures by a double cellular precipitation reaction. The first decomposition product consists of alternate lamellae of an Ni3Ti(DO24) phase and austenite. The reaction proceeds to completion, consuming all of the original austenite. This first cellular product is subsequently consumed by a second cellular reaction of much coarser spacing. The first cellular reaction was studied in detail by light and electron microscopy, hardness measurements, and by X-ray and electron diffraction. Interlamellar spacings and growth rates were measured during isothermal aging in the range 400" to 975°C. The orientation relationship between the Ni3Ti and austenite lamellae was determined and indicates that an almost perfectly coherent interface exists between the two phases. This first Ni3Ti cellular reaction is of particular interest because it occurs over such a wide temperature interval. This allows cellular growth rates and interlamellar spacing data to be obtained for much larger degrees of undercooling than reported hitherto. MATERIALS AND EXPERIMENTAL PROCEDURE The Fe-30 Ni-6 Ti alloy was prepared from electrolytic iron, Mond nickel shot, and sponge-purity titanium* by vacuum melting in a zirconia crucible

Jan 1, 1963

By Arnulf Muan, D. P. Masse

PHASE relations in the system CoO-SiO2 have been determined as a basis for further investigations of thermodynamic properties of olivine solid solutions involving Co2SiO4 as a component. Previous data on the system CoO-SiO2 are incomplete or uncertain. Biltz and Lemke1 determined the melting point of cobalt orthosilicate as 1345°C , but Asanti and Kohlmeyer2 have later found a considerably higher temperature, 1420°C. The latter authors also studied melting relations of one mixture on the CO side and two mixtures on the SiO2 side of the orthosilicate composition and sketched a tentative phase diagram for a limited composition range of the system. However, no phase identification was carried out, and the authors left unanswered the question of the possible existence of a stable meta-silicate phase. Greig3 showed that a 90 wt pct SiO2-10 wt pct Co mixture at 1725°C consists of two immiscible liquid phases. The quenching technique was used in the present investigation. Mixtures of high-purity cobalt oxide ("Fisher Certified") and dehydrated silicic acid ("Baker Analyzed") were equilibrated in air atmosphere. The samples were then quenched to room temperature and the phases present were identified by microscopic and X-ray examination. The samples were kept in small envelopes made from thin (0.0004 in.) platinum foil. Thermodynamic data which have become available recently for Pt-Co alloys4 were used to check that the losses of COO from the oxide samples by alloying of cobalt with platinum in the present investigation were too small to change significantly the compositions of the oxide material during the equilibration. A vertical tube furnace with an 80 pct Pt 20 pct Rh resistance winding was used in runs up to 1510°C. Temperatures in these runs were measured with a Pt vs 90 pct Pt 10 pct Rh thermocouple calibrated against the melting point of diopside (CaMgSi2O6, 1391.5?C). The given temperatures as measured by this technique are estimated to be accurate to *5°C. Quench runs at temperatures above 1650°C were made with a modified Roberts and Morey5 strip furnace, using strip resistors composed of a 60 pct Pt-40 pct Rh alloy. Temperatures were measured with an optical pyrometer which was calibrated against the liquidus temperature of a mixture composed of 10 wt pct CaO, 90 wt pct SiO2 (1707°C). The temperatures measured with this technique have an estimated accuracy of +15°C. The results are shown graphically in Fig. 1. Only one intermediate phase, the orthosilicate Co2SiO4 with olivine-type structure, is stable in addition to the end members cobalt oxide and silica. The melting point of the orthosilicate was found to be 1415" ± 5°C. The metastilicate CoSiO3 is not stable at the temperatures of the present investigation. The two eutectic points in the system CoO-SiO2 where COO plus olivine, and olivine plus silica, coexist with liquid were found to be 72 wt pct COO and 1407°C and 63 wt pct COO and 1381°C, respectively. The melting point of cobalt oxide in air was taken as 1745?C, based on the previous data of Aukrust and Muan.6 Within limits of error (+ 5?C), identical eutectic temperatures to those determined in air were found when two representative mixtures were equilibrated at 1 atm O2 pressure and in an atmosphere of 84 vol pct CO2, 16 vol pct H2. This suggests that changes in oxidation state of cobalt in the condensed phases are not significant as far as their effect on the phase relations are concerned. This inference was substantiated by failure to detect7 any "excess oxygen" (i.e., oxygen in excess of that contained in Co2SiO4) in a sample of orthosilicate composition equilibrated in air 10°C above the liquidus temperature and subsequently quenched to room temperature. This work was carried out as part of a research program sponsored by the U.S. Atomic Energy Commission under Contract No. AT(30-1)-2781.

Jan 1, 1965

By S.H. Ash, P.S. Miller

Extensive and diversified resources justify large populations and great industries. To carry on the business of commerce and meet the demands of large populations, the utilization of tunnels in some form for transportation purposes constitutes an important link in modern civilization. The driving of tunnels has been appropriated by the tunneling branch of the heavy-construction industry, and the progressive steps taken by modern tunnel builders were not even dreamed of 50 years ago. Great strides have been made toward more rapid progress in tunneling in the United States during the past I0 years. Tunneling consists of a definite cycle of operations developed from ideas that are crystallized and translated into action programs through various engineering phases that begin with the first preliminary survey and do not end until the job is completed. Once the line of the bore is established and a time set for the completion of the work, the face must advance according to estimates prepared before the work commences. This schedule must be followed in regular sequence from the moment the drills start against a new face of rock until they are ready again to drill the Succdeding face, constituting a round. Mining is largely tunneling carried on under conditions often more inherently hazardous than actual tunnel construction, but for various reasons" tunne1ing is more hazardous than mining in any branch of the mineral industry. On the other hand, obstacles are sometimes encountered in heavy-construction tunneling projects that when met in mining enterprises do not offer comparable tasks to avoid or overcome them. One is the existence of water under high pressures. In mining enterprises, various alternatives offer a solution in driving a tunnel, even to the extent of its discontinuance or the abandonment of the mine, but a "construction" tunnel usually must go forward because some important project depends largely if not entirely upon it. This paper describes an unusual method of driving a water-supply tunnel through rock carrying water under pressures and conditions that did not permit the use of ordinary tunneling methods. The Delaware Aqueduct The new Delaware aqueduct is a Manhattan project of some magnitude; when regular it will contain what probably will be, for some time to come, the longest tunnel in the world. Various features in its construction are currently described in the trade journals of the construction industry, and informative engineering details are given in the Delaware Water Supply News, published twice a month by the Board of Water Supply of the City of New York. Work was begun on this project on March 24, 1937. The tunnel will convey water from reservoirs at the headwaters of the Delaware River to the City of New York.

Jan 1, 1943

By P. S. Miller, S. H. Ash

Extensive and diversified resources justify large populations and great industries. To carry on the business of commerce and meet the demands of large populations, the utilization of tunnels in some form for transportation purposes constitutes an important link in modern civilization. The driving of tunnels has been appropriated by the tunneling branch of the heavy-construction industry, and the progressive steps taken by modern tunnel builders were not even dreamed of 50 years ago. Great strides have been made toward more rapid progress in tunneling in the United States during the past I0 years. Tunneling consists of a definite cycle of operations developed from ideas that are crystallized and translated into action programs through various engineering phases that begin with the first preliminary survey and do not end until the job is completed. Once the line of the bore is established and a time set for the completion of the work, the face must advance according to estimates prepared before the work commences. This schedule must be followed in regular sequence from the moment the drills start against a new face of rock until they are ready again to drill the Succdeding face, constituting a round. Mining is largely tunneling carried on under conditions often more inherently hazardous than actual tunnel construction, but for various reasons" tunne1ing is more hazardous than mining in any branch of the mineral industry. On the other hand, obstacles are sometimes encountered in heavy-construction tunneling projects that when met in mining enterprises do not offer comparable tasks to avoid or overcome them. One is the existence of water under high pressures. In mining enterprises, various alternatives offer a solution in driving a tunnel, even to the extent of its discontinuance or the abandonment of the mine, but a "construction" tunnel usually must go forward because some important project depends largely if not entirely upon it. This paper describes an unusual method of driving a water-supply tunnel through rock carrying water under pressures and conditions that did not permit the use of ordinary tunneling methods. The Delaware Aqueduct The new Delaware aqueduct is a Manhattan project of some magnitude; when regular it will contain what probably will be, for some time to come, the longest tunnel in the world. Various features in its construction are currently described in the trade journals of the construction industry, and informative engineering details are given in the Delaware Water Supply News, published twice a month by the Board of Water Supply of the City of New York. Work was begun on this project on March 24, 1937. The tunnel will convey water from reservoirs at the headwaters of the Delaware River to the City of New York.

Jan 1, 1943

By F. E. Streigert, J. H. Mallery, A. H. Geisler

The existing data on precipitation in Cu-Be alloys have been reconciled with some new data to present a more complete and rational analysis of the atomic rearrangements involved in the process. Two different coherent precipitates were proposed. Each is responsible for a type of diffuse X-ray diffraction effect. THE nature of the atomic rearrangement involved in the precipitation of the compound y-Cu-Be from supersaturated solid solutions of the copper-base alloys has been the subject of two extensive investigations.'-" he precipitate in this alloy system has a rather simple structure; at equilibrium it has a body-centered cubic unit cell with copper atoms on the corner sites and beryllium atoms on the center site. While a simple mechanism would be expected to obtain for the precipitation process, those which have been proposed do not adequately explain all of the reported data. The purpose of the present report is to rationalize some of the previous observations and to contribute new data on the subject obtained by the usual techniques of structure analyses. The Cu-Be system of alloys represents one of the most extensively investigated precipitation systems, so a detailed review of the pertinent literature on structure is in order. Striations: Since one of the important features of the mechanism—the habit plane—is determined by microscopic examination, microstructural features that have been observed should be considered at this time in order to assess their role in the precipitation process in Cu-Be alloys. One of the most prominent features appears as regularly oriented markings or stripings (ripples or striations) across the crystals on a suitably polished and etched sample of the aged alloy. These have been observed and interpreted by many workers. Masing and Dah14 observed striations in both the a and /3 phases of a 2.5 pct Be alloy, and attributed them to the beginning of the precipitation of very fine y crystals along favored planes of the a matrix and to the local decomposition of the £ crystals into a plus y. These markings were apparent in both the a and /3 phases of the micrographs given by Smith5 for a 2.75 pct Be alloy, while Moore" detected them in the a matrix phase using polarized light. Desch7 attributed the markings to fine precipitate particles lined up on a family of matrix planes like Masing and Dahl had done, and he identified the planes as those of the (111) family, the slip planes of the matrix. The striations were presumably the structure which Northcott- eferred to as "martensitic." He found that this structure was present in samples that had been aged under widely different conditions with hardness values ranging from 160 to 400 VHN. Later Guinier and Jacquet' also found striations in both the a matrix and secondary /3 phase. Their analyses showed that the striations were along (110) planes of the matrix phase, apparently in contradiction of the results of Desch. They found that the striations were developed during aging on the surface of a specimen that had been polished prior to aging.' On this basis they concluded that the striations represented mechanical deformation by slip along (110) planes of the matrix resulting from precipitation stresses.'" Similar but fainter striations were observed in the same manner on an A1-Cu alloy sample, in which the change in volume was much less than for Cu-Be alloys and

Jan 1, 1953

By L. E. Snow, L. F. Pett

AT the Utah Copper Pit of Kennecott Copper Corp. a versatile mobile drill unit has been developed and tested. Through increased drilling speed and additional available drilling time, an improvement of 233 pct in drill performance has been realized. Operators using drill power can quickly and easily convert the unit from a vertical to a toe hole drill. Drilling is done with the machine in line with the unit or at right angles to it. Table I covers the 1950 drill record at the mine, showing the types of machines used and the footage obtained. Development of the new units was prompted by a desire for solution of the following problems: 1—The ever-expanding operations within the Utah Pit, requiring some 65 miles of transmission pipe lines radiating from a central compressed air plant, have now taxed this compressor plant beyond capacity. While 100 lb per sq in. pressure is maintained at compressors, transmission losses from innumerable small leaks result in low terminal pressure at the drills. Fig. 1 illustrates that while terminal pressure varies according to size of air hose and fittings used, the average drill is operating on air pressures within the 60 to 70-lb range. The compressor plant is operated primarily for air rock drills. All drilling is done on day shift, but it is necessary to run two of the three 3720 cu ft capacity compressors during night shift in order to prevent drastic loss of pressure through leaks. On day shift all three compressor units are operated at capacity, so that there is no reserve safeguard available for extensive repairs to any compressor. The calculated volume of compressed air required for operation of 25 drills is but 33 pct of three day-shift compressors. While compressed air is being used to a minor extent for purposes other than drilling, it is felt that satisfactory substitute facilities could be pro- vided in the event that air lines were no longer available. 2—Drill performance has increased beyond the capacity of present 3-in. drifter machines. 3—The installation, maintenance, and moving of air lines in routine mining is a growing problem. The 2-in. level lines are placed outside electrification towers and must be moved to new location upon completion of each shovel cut. In addition to these moves it is often necessary to dismantle level lines so that excessive shovel spillage, or material covering track following a blast, can be pushed in the clear with bulldozers. Where level room is limited, it is often necessary to remove air lines in giving bulldozers room to prepare grades for wagon drills. In spite of precautions taken, many level lines become buried, twisted, and constricted, with excessive air loss resulting. Excessive back break in blasting often leaves several sections of air line suspended in mid-air. Occasionally air lines come in contact with defective electric transmission towers, so that holes are burned through pipe. 4—Rail-handling of drilling equipment such as wagon drills from one location to another requires considerable locomotive crane crew time. Any new unit developed should travel under its own power. 5—Present practice requires accessory material including hose, water pressure tanks, water barrels, drill steel, and bits to be transported by means of push cars when drill locations are changed on any level. 6—In order to supply numerous drill locations with material, many stock piles of new drill rods, drill bits, and other essentials must be left at strategic points, usually in the vicinity of powder magazines. This practice makes for poor housekeeping and contributes to the loss of supplies. Planning the Unit It was felt that a mobile drill unit which would rectify the foregoing problems should meet certain demands: 1—It must furnish compressed air to operate a 4-in. rock drill at a pressure of 90 to 100 lb.

Jan 1, 1953

By L. E. Snow, L. F. Pett

AT the Utah Copper Pit of Kennecott Copper Corp. a versatile mobile drill unit has been developed and tested. Through increased drilling speed and additional available drilling time, an improvement of 233 pct in drill performance has been realized. Operators using drill power can quickly and easily convert the unit from a vertical to a toe hole drill. Drilling is done with the machine in line with the unit or at right angles to it. Table I covers the 1950 drill record at the mine, showing the types of machines used and the footage obtained. Development of the new units was prompted by a desire for solution of the following problems: 1—The ever-expanding operations within the Utah Pit, requiring some 65 miles of transmission pipe lines radiating from a central compressed air plant, have now taxed this compressor plant beyond capacity. While 100 lb per sq in. pressure is maintained at compressors, transmission losses from innumerable small leaks result in low terminal pressure at the drills. Fig. 1 illustrates that while terminal pressure varies according to size of air hose and fittings used, the average drill is operating on air pressures within the 60 to 70-lb range. The compressor plant is operated primarily for air rock drills. All drilling is done on day shift, but it is necessary to run two of the three 3720 cu ft capacity compressors during night shift in order to prevent drastic loss of pressure through leaks. On day shift all three compressor units are operated at capacity, so that there is no reserve safeguard available for extensive repairs to any compressor. The calculated volume of compressed air required for operation of 25 drills is but 33 pct of three day-shift compressors. While compressed air is being used to a minor extent for purposes other than drilling, it is felt that satisfactory substitute facilities could be pro- vided in the event that air lines were no longer available. 2—Drill performance has increased beyond the capacity of present 3-in. drifter machines. 3—The installation, maintenance, and moving of air lines in routine mining is a growing problem. The 2-in. level lines are placed outside electrification towers and must be moved to new location upon completion of each shovel cut. In addition to these moves it is often necessary to dismantle level lines so that excessive shovel spillage, or material covering track following a blast, can be pushed in the clear with bulldozers. Where level room is limited, it is often necessary to remove air lines in giving bulldozers room to prepare grades for wagon drills. In spite of precautions taken, many level lines become buried, twisted, and constricted, with excessive air loss resulting. Excessive back break in blasting often leaves several sections of air line suspended in mid-air. Occasionally air lines come in contact with defective electric transmission towers, so that holes are burned through pipe. 4—Rail-handling of drilling equipment such as wagon drills from one location to another requires considerable locomotive crane crew time. Any new unit developed should travel under its own power. 5—Present practice requires accessory material including hose, water pressure tanks, water barrels, drill steel, and bits to be transported by means of push cars when drill locations are changed on any level. 6—In order to supply numerous drill locations with material, many stock piles of new drill rods, drill bits, and other essentials must be left at strategic points, usually in the vicinity of powder magazines. This practice makes for poor housekeeping and contributes to the loss of supplies. Planning the Unit It was felt that a mobile drill unit which would rectify the foregoing problems should meet certain demands: 1—It must furnish compressed air to operate a 4-in. rock drill at a pressure of 90 to 100 lb.

Jan 1, 1953

By Hugh Rose

JAY A. CARPENTER, Tonopah, Nev: (communication to the Secretary*).-This description of the Santa Gertrudis mill is of great interest to the operators of similar silver mills in Nevada. At the San Francisco meeting last September there were two excellent papers presented on Nevada silver mills; one by A. H. Jones on The Tonopah Plant of the Belmont Milling Co., and the other by E. E. Carpenter on Cyaniding Practice of the Churchill Milling Co., Wonder, Nev. At the same meeting, I presented a paper on-Slime Agitation and Solution Replacement Methods at the West End Mill, Tonopah, Nev., covering this .particular feature of our milling practice. A comparison of the data presented in these four papers is interesting in that, while the general design and practice is much the same in all cases, there is a wide difference in the design and practice in the various departments of 'the mills. It is to be regretted that Mr. Rose did not round out. this excellent article by following Mr. Jones's and Mr. Carpenter's' lead in giving the average gold and silver content of the ore milled and the resulting tailing, with the consumption of chemicals and the? cost of milling. The practice of the Santa Gertrudis mill in the use of ?cyanide and zinc offers an interesting comparison with that of the Nevada mills, and a discussion of this point may bring out the reasons for the differences that exist.

Jan 12, 1916

By R. W. Jordan, J. Winter, A. J. Goldman

Kirkendall diffusion of copper and nickel atoms across the bond interfaces, as well as oxygen diffusion in the core to the interfaces, are the mechanisms which control the variation in bond strength with annealing time at 1600°to 1800°F in the cupro-nickel clad copper Mint composite. The unequal mass transfer resulting from the high diffusion rate of copper in cupro-nickel compared with that of nickel in copper caused void formation in the core. Small voids also formed in the cladding after short annealing times. These may have been nucleated by nickel oxide particles which are formed by the dissociation of the cuprous oxide in the core and the movement of oxygen to the cupro-nickel interfaces. The bond strength drops to very low values for annealing time up to 3 hr when the void density is greatest. The increase in bond strength after 16 to 72 hr at 1600°F is a result of the decrease in the void density in the cupro-nickel cladding and the growth of grains across the interface. The void density decrease is attributable to grain boundary diffusion of vacancies to the surface. The abnormally large grains in the copper preclude a similar process from taking place in the core. THE solution to many engineering materials problems that cannot be satisfied by using a single metal or alloy is often attained by combining two or more metals in such a way that each component performs a different function, while the composite meets the overall requirements. The Coinage Act of 1965 authorized a changeover from the traditional 90 Ag-10 Cu dimes and quarters to a bimetallic laminate of 75 Cu-25 Ni clad on a copper core. Economic considerations as well as physical, chemical, and mechanical properties provided a basis for the selection of this composite as a substitute for the silver-bearing alloy. An extensive survey of alloys suitable for use as coinage was prepared by Battelle Memorial Institute for the U.S. Mint.1 It was found that the cupro-nickel/cop-per/cupro-nickel composite satisfied the required color, density, mechanical properties, corrosion resistance, electrical properties, and magnetic properties to make it completely acceptable to the general public and the vending machine industry. This investigation is part of a program to determine the feasibility of reclaiming composite scrap by thermally degrading the bond strength of the cupro-nickel clad copper laminate. The composite exhibits bond degradation and subsequent bond improvement during annealing in the temperature range 1600" to 1800°F. A study of the operative diffusion processes and the resultant structural changes was made in order to explain the observed variations in bond strength with annealing time. EXPERIMENTAL PROCEDURES AND RESULTS Bond Degradation. A measurement of the forces required to peel the cupro-nickel cladding from the

Jan 1, 1969

By John Carter Anderson

The theory of a zonal deposition of ores from ascending solutions which were differentiation products of a cooling magma, first propounded by Spurr,l in a measure explained by Lindgren,2 and recently re-emphasized by kemp,3 while perhaps accepted in principle by many mining geologists, so far has not been accepted as capable of practical application in the study and development of ore deposits. From his observations, the writer is convinced that there are laws governing the primary deposition of ores which, when properly worked out, will be of greatest economic value; and that the application of this knowledge to the development of new mines will mark an advance in the mining industry similar to that following the working out and application of the theory of secondary enriehiment. That there has been a tendency to a zonal distribution in the formation of ore deposits, by which the ores of one metal have been precipitated from tile mincralizing solutiolis at a greater distance from the source than those of another, cannot be disputed; and the nature of this zoning in a given deposit or district has been frequently described.4 But that a selection precipitation of the ores of two or more metals, other than lead and zinc, in successive zones may have taken place in a single deposit within limits economically possible of exploration is not generally recognized or admitted.

Jan 1, 1923

By John Carter Anderson

The theory of a zonal deposition of ores from ascending solutions which were differentiation products of a cooling magma, first propounded by Spurr,l in a measure explained by Lindgren,2 and recently re-emphasized by kemp,3 while perhaps accepted in principle by many mining geologists, so far has not been accepted as capable of practical application in the study and development of ore deposits. From his observations, the writer is convinced that there are laws governing the primary deposition of ores which, when properly worked out, will be of greatest economic value; and that the application of this knowledge to the development of new mines will mark an advance in the mining industry similar to that following the working out and application of the theory of secondary enriehiment. That there has been a tendency to a zonal distribution in the formation of ore deposits, by which the ores of one metal have been precipitated from tile mincralizing solutiolis at a greater distance from the source than those of another, cannot be disputed; and the nature of this zoning in a given deposit or district has been frequently described.4 But that a selection precipitation of the ores of two or more metals, other than lead and zinc, in successive zones may have taken place in a single deposit within limits economically possible of exploration is not generally recognized or admitted.

Jan 1, 1923