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By Herbert Hoover

IT is always a pleasure for me to join in the Ameri-can Mining Congress, for not only has my own professional life been closely linked with the industry, but the Secretary of Commerce is specifically enjoined in the organic act creating the office to promote and foster the interests of the mining industry. And it is a vital part of our national life. It is one of those indus-tries without which. the nation could not go on for a week. It ranks second only to the agricultural industry in its contribution to our raw materials. Its production amounts to nearly 6 ½ billions annually, providing direct support to probably ten millions of our people through employment to about two million workers. But the in-dustry has a greater importance than even these figures indicate, for with agriculture, forestry, and water power it furnishes the raw materials upon which the whole work of our civilization rests. When the raw ma-terials of our mines emerge. from manufacture with the added expenditure of labor and capital upon them, they have a wholesale value of over fifteen billions of dollars. And in this, the second stage of their application, they give employment to another two million workers and support to about ten million more of our people. A large portion of these manufactured commodities must filter through the retail trade; their total value when delivered to the consumer exceeds twenty billions of dollars. And from this distribution arises the support of many more millions of our people. It is estimated that the products of agriculture when they reach . the consumer, with transportation, manu-facturing, and distribution costs added, have about the same value as the mineral industries-each of them thus contributing about one-quarter of our total na-tional income. No other continent has demonstrated its possession of such a magnitude of minerals as has ours, and such a bountiful distribution over our whole land. But our mineral resources differ in one essential from our other natural resources-they are not renewable. Agricul-ture, forests, and water power replenish their supplies from season to season. Some people conclude from the non-renewable character of the mineral supply that they must shortly be exhausted. The practical question is ,one of time, and time in these matters needs to be measured in generations, and apprehension of exhaus-tion needs to be tempered with many probabilities in-cluding the advance in technical methods of extraction. In some of our minerals, such as coal, iron, and building materials we can, through a knowledge of their geologi-cal structure and occurrence, make fairly good estimates of our reserves. We. know that they will outlast many generations of Americans. In non-ferrous metals and oil, geology affords us no great basis for an estimate of future supply. We only know of the occurrence of minerals of this type by actual exposure of them, and we can thus make no estimates except upon reserves which have been proved by actual development by the process of mining. To develop them ahead merely for national satisfaction of assured future supply would imply an unbearable waste of capital. The consequence is that in these groups there is never a demonstrable assurance of more than a few years' supply ahead of us. Yet we have never failed from year to year to find new deposits and extension of old deposits.

Jan 1, 1928

By T. A. Simpson

The search for ore continued at its relentless pace throughout 1967. Canada, South Africa and Australia plus a few scattered localities on the globe reported minerals finds of significant importance. Many of the reported finds were not high grade ore, but they nonetheless will assist in sup- plying a highly industrialized, mineral hungry world. No longer does inaccessibility and remoteness close an area to mineral exploration and development. The communication and transportation systems of today have closed the gap and, moreover, the demand for essential mineral commodities is causing price shifts which encourage exploitation of deposits heretofore considered uneconomical.

Jan 2, 1968

By Anson Hayes, John Chipman

The quality of sheet and strip products made of rimming steel is closely related to the structure and chemistry of the ingots. The variation in composition throughout the ingot, as affected by segregation, is of great importance, as are also the form and distribution of the voids that result from the gases evolved. It is because of this importance that the considerable literature in this field has accumulated. No attempt is made in the present paper to compile a bibliography of the excellent work that has already been done, as this has been adequately covered in the many excellent reports on the heterogeneity of steel ingots prepared by a joint committee and published by the Iron and Steel Institute.' From time to time, in any field of investigation new tools and new technique are developed, which make further progress possible. In the field with which this paper is concerned, this is true. The development of the vacuum-fusion method as a means of following oxygen segregation, and a technique for obtaining the volume and composition of the gases evolved during solidification, have opened the way to obtaining data by means of which some considerable progress has been realized in developing more of the detailed mechanisms of solidification and segregation in rimming-steel ingots. General Theory of Segregation The basic cause of segregation lies in the fact that the impurities are less soluble in solid than in liquid iron. The solid that forms from the impure liquid is more nearly pure than the liquid itself. If solidification proceeds slowly enough, or if the liquid and solid phases are maintained in contact with one another for a sufficient time, a condition of equilibrium is set up, which may be represented by a phase diagram. Portions of the

Jan 1, 1939

By Anson Hayes, John Chipman

The quality of sheet and strip products made of rimming steel is closely related to the structure and chemistry of the ingots. The variation in composition throughout the ingot, as affected by segregation, is of great importance, as are also the form and distribution of the voids that result from the gases evolved. It is because of this importance that the considerable literature in this field has accumulated. No attempt is made in the present paper to compile a bibliography of the excellent work that has already been done, as this has been adequately covered in the many excellent reports on the heterogeneity of steel ingots prepared by a joint committee and published by the Iron and Steel Institute.' From time to time, in any field of investigation new tools and new technique are developed, which make further progress possible. In the field with which this paper is concerned, this is true. The development of the vacuum-fusion method as a means of following oxygen segregation, and a technique for obtaining the volume and composition of the gases evolved during solidification, have opened the way to obtaining data by means of which some considerable progress has been realized in developing more of the detailed mechanisms of solidification and segregation in rimming-steel ingots. General Theory of Segregation The basic cause of segregation lies in the fact that the impurities are less soluble in solid than in liquid iron. The solid that forms from the impure liquid is more nearly pure than the liquid itself. If solidification proceeds slowly enough, or if the liquid and solid phases are maintained in contact with one another for a sufficient time, a condition of equilibrium is set up, which may be represented by a phase diagram. Portions of the

Jan 1, 1939

By Ross W. Smith, Salim Akhtar

INTRODUCTION Flotation of oxide minerals, particularly silicates, with cationic collectors differs substantially from classic flotation of sulfide minerals using sulfhydryl collectors. In the case of cationic flotation of these minerals, in general: 1. There is a greater importance of electrostatic interaction between mineral and collector. 2. Longer-chained collectors are required; as a rule at least 10 carbons must be present in the hydrocarbon chain. 3. Moderate concentration of collector is required. 4. Attachment between collector and mineral appears to be less strong even though the system may exhibit a large contact angle. 5. Required conditioning time before flotation is usually relatively short. 6. There is sensitivity to slimes. 7. The collectors usually possess frothing power. 8. Selectivity of cationic collectors for specific minerals is usually poor. Almost any of the oxide and silicate minerals may be floated using cationic collectors. However, specific response to these collectors varies with mineral type. The following classes and minerals are

Jan 1, 1976

By Edgar Kidwell

To any one acquainted with the practical conditions surrounding the mining engineer and mine-manager, especially in this country, the presentation to the American Institute of Mining Engineers of a paper on the above subject will need no explanation. The members of this profession are continually called upon to design and erect, both above and underground, structures which involve the use of beams. Not to mention the various buildings connected with large mining operations, I need only refer, in support of this statement, to trestles, derricks, headworks, etc., on the surface, and to timbered stations and other spaces of large span in the mine-workings. Notwithstanding the rapidity with which iron and steel are replacing wood in the construction of large buildings, there will always be cases in which the use of metal will be unadvisable. Especially will this be true in districts remote from large cities. Works of temporary character will continue to use timber. High freight-charges, the liability of delays in delivering iron, and the temporary character of many of the structures, will for many years to come make it advantageous for the mines west of the Mississippi and on Lake Superior to construct their buildings almost exclusively of wood. The timber-resources of the country are decreasing so rapidly that already the engineer finds difficulty at times in obtaining beams of large size. This difficulty will steadily increase, and will force the constructor to resort more frequently to built-up beams, such as have long been used in Europe, owing to the difficulty of obtaining there such large sizes of timber as have

Jan 1, 1898

By J. M. Johns

INTRODUCTION The Climax Mine is located on the continen¬tal divide, on Fremont Pass, about 145 Km south west of Denver, Colorado. Molybdenum, along with the by products, tungsten, tin, and pyrite are produced from both the open pit and under¬ground operations. The underground operation utilizes a panel caving mining system, and produces in excess of 27,000 mt per day. In the mid 1930's, the Climax mine began changing from a grizzly level layout to the slusher drift system which is still in use to¬ day. Over the years, the slusher drift layout has been refined to correct, improve, and sim¬plify minor operational problems. In common with most older hardrock mines, the development equipment used at Climax was the standard rail mounted, pneumatic mining machinery. This type of equipment remained in use, at least to some degree, until about four years ago. For production, 112 Kw electric slushers were used, while mine traffic was rail with trolley locomotives. Beginning about ten years ago, Climax began

Jan 1, 1981

By N. Tiner

THE mechanical properties of magnesium-alloy castings are greatly improved by grain refinement, and at present considerable attention is being paid to methods of obtaining fine-grained castings. One method of achieving this end is the use of proper melting and superheating techniques. These have been employed commercially to a great extent, but no comprehensive study of the subject appears to have been published at present. Numerous investigations found in the literature include some reference to superheating techniques, 1-4 and Achenbach, Nipper and Piwowarsky,5 based principally on thermal analysis, ascribe the grain-refining action of superheating to the influence of solid foreign particles or dissolved gases present in the melt upon the course of crystallization. The primary purpose of this paper is to present the principal facts concerning the effect of superheating on grain size of magnesium alloys. Attempts are also made to explain the experimental results in terms of a general hypothesis. The investigations are limited chiefly to common commercial casting alloys. In order to carry on this work, it was necessary to determine the factors influencing grain size and to develop a proper technique for the preparation of samples. The preliminary tests made by the author indicated that the grain size of magnesium alloys resulting from the solidification of a melt is determined by alloy composition, presence of impurities, rate of cooling during solidification, thermal history of the melt and to some extent the structure of the charge used. The rate of cooling is in turn dependent upon the mass of the melt, pouring temperature, and dimensions, properties and temperature of the mold into which the melt is poured. The final grain size of the alloys is still further modified by heat-treatment subsequent to casting. It is not within the scope of the present paper to discuss all of these factors, and it would suffice to note here that when equal amounts of magnesium alloys are prepared from the same alloying materials, melted in graphite crucibles under the same thermal conditions, then cast into graphite molds at a constant temperature, the .resultant solids have the same grain size. By maintaining all other factors constant, it is thus possible to vary thermal conditions of a melt and to examine the grain size of resultant castings. PREPARATION OF SAMPLES AND GRAIN-SIZE TESTING The alloys investigated in this paper were taken from ingots made by Permanente Metals Corporation or prepared by the author with pure carbothermic magnesium and necessary alloying elements. Melting was carried out under a flux in a graphite crucible heated uniformly by an

Jan 1, 1945

By J. G. Faller, L. P. Skolnick

The distribution of cobalt and vanadium over non-equivalent crystallographic sites in C14-type Zr(VCo), alloys has been investigated. An anomalous X-ray scattering technique developed by Skolnick, Kondo. and lavine7 by which the separation in the scattering factors of two similar atoms can be enhanced was employed. Six alloys spanning the pseudobinary section ZrV1.6Co0.4-ZrVO.6CO1.4 at 10pct steps showed a nonrandom compositionally dependent distribution. Specifically, at high vanadium content cobalt preferentially occupied sites of type (6h) and vanadium, sites of type (2a; at low vanadium content the reverse was observed. In addition to the distribution fraction the structural parameters x and z were obtained. There was no significant deviation of these parameters from those obtained in the ideal C14 structure. Certain suggestions are made to account for the observed nonrandomness in the distribution of atoms on the two types of sites. INTERMETALLIC compounds of formula AB2 iso-morphous with MgCu2, MgZn2, and MgNi2 are known as Laves phases. Because Laves phases exhibit high symmetry and coordination numbers, the highest possible for an AB2-type compound,1 they are among the most frequently observed compounds in nature. In recent years interest has centered about the purely transition metal Laves phases2-' in efforts to understand the function of atomic size and electronic structure in the formation of these compounds. It has been observed that pseudobinary Laves phase systems often show a variation of structure across the phase diagram. Such a system is the ZrV2-ZrCo2 in which the structure varies from cubic MgCu2 to hexagonal MgZn2 to cubic MgCu2.4 Some understanding about the conditions under which the second modification is stable can perhaps be gained by studying the distribution of cobalt and vanadium atoms on lattice sites in the MgZn2 modification of the system ZrV2-ZrCo2. In both the MgZn2 and MgNi2-types there exist nonequivalent positions open to occupancy by the B element, whereas in the MgCu2 prototype all sites are equivalent. Skolnick, Kondo, and La-vine7 have developed an anomalous scattering technique suitable for this type of investigation. Whereas the influence of size on the formation of a Laves phase is well recognized, no substantial evidence has been put forth in support of the size ratio dependence of a particular prototype. Berry and Raynor8 suggested that RA /RB ratio does indeed affect the type of structure that is chosen, MgZn2 compounds tending to cluster about 1.225 while MgCu2 compounds were found at larger deviations from this ratio. Dwight,3 however, from a study of 164 Laves phases does not believe this generalization to be justified. Electronic effects are certain to play a part in the stability of Laves phases in general and in the choice of a structure type in particular. For example, size along would favor the formation of Laves compounds of Ti, Zr, Hf, Ta, or Nb as the A element with nickel or copper as the B element. The absence of such is attributed to an unfavorable electron : atom ratio by Elliott and rostoker.4 Early experiments of Laves and witte9 with pseudobinary and pseudoternary systems of the three prototypes established the dependence of crystal structure upon electron: atom ratios. They observed that the MgCu2 structure dissolved elements of higher valency until the electron: atom ratio of =1.8 was reached; the MgZn2 likewise dissolved elements of lower valency replacing zinc. witte,6 from calculations of the electron : atom volumes of Brillouin Zones, obtained limits of stability for the prototypes MgCu2 and MgZn2. Elliott and Rostoker4 used these limits with considerable success in the all-transition element Laves phases they investigated. According to witte,6 compounds between the electron :atom ratios of 1.80 and 2.32 were of the MgZn2 type; those above and below exhibited the MgCu2-type structure. On the basis of these limits and an assumed valency of zirconium based upon the near tetra-valence of titanium, Elliott and Rostoker obtained valencies for the first transition series elements. For the Laves phases with which this investigation is concerned, ZrV2 and ZrCo2, the authors calculated electron :atom ratios of 2.54 and 1.56, respectively. These ratios are for the MgCu2-type structure and straddle the stability band of the MgZn2 modification. One could, therefore, predict that a pseudobinary system ZrV2-ZrCo2 should pass through the MgZn2 modification in traversing the composition diagram from one end to the other. Implicit in this assumption is a smooth change of the electron: atom ratio from 2'54 to 1.56. MOSS10 states that his finding the low temperature structure of ZrCr2 to be C15 instead of C14 alters greatly Elliott's valency of zirconium and hence the assumed valencies of the other metals. Such a quantitative correlation of structure with electron : atom

Jan 1, 1963

By R. J. Charles, G. Agar

Experiments on single particles show that the amount of material created during impact that is finer than any chosen size is proportional to the energy of the impact. As the underlying principle of comminution, it might be stated that each unit of energy input to a given comminution system tends to add to the system an identical assembly of new particles and subtract an equivalent volume of larger particles. Thus, two of the consequences of the fact that each unit of energy tends to add identical assemblies of new particles to the system are: 1) on continued application of energy the total charge in any batch comminution system tends to assume the characteristics of this assembly, and 2) the process of comminution may be described by a relationship such as E = Ak-a. Recently Schuhmannl presented a theory of comminution which puts rational perspective on the extensive controversy surrounding most of the existent theories of comminution. With hindsight the origin of controversy can be ascribed to a relatively simple circumstance. In general, a progressive shift of a size distribution curve towards finer sizes is observed as energy is added to a comminution system. It is also observed that, with continued grinding, the size distribution curves usually change and appear to approach some constant shape. Inves-tigators generally felt that an appropriate method of relating and generalizing such data would be to consider the hypothetical case where particles in the system were uniformly subjected to comminution such that each of these particles, receiving its proportion of input energy, was transformed into a number of smaller particles of uniform size. Since the changes in shape of the size distribution curves during size reduction were clearly associated with the coarse particles in the system, it was also assumed that these changes accounted for little of the input energy and one could deal solely with the equilibrium shape towards which the size distribution curves tended. Although the unrealistic nature of the foregoing points of view was realized some justification was felt for such treatments since, in most cases, the resulting mathematical formulae could, by the adjustment of at most two parameters, satisfactorily describe experimental observation. Difficulties arose, however, in that the formulae required a specific influence of the feed size on the comminution process. In actual fact, the application of a feed size term in fitting experimental data was often found to be unnecessary or contrary to the above formulae. Secondarily, much discussion arose concerning the appropriate energy number that would relate the size change of one particle to the amount of comminution energy it received. As has been previously shown3 all the above theories that treat comminution as a continuous process of size reduction may be related to a proposition of the following form: dE = -Cfn [1] where dE is the increment of energy, dx is the size change, x is the particle size, and C and n are constants. It is now clear, as pointed out by Schuhmann, that Eq. 1 is inapplicable to comminution processes, since comminution cannot be considered other than as a discontinuous mixing process in which the overall size distribution of the product results from mixing, in various proportions, finished material with unfinished, and sometimes untouched, material. A striking illustration of this mixing phenomena may be obtained by comparing the size distributions of grinds in a typical batch ball mill with size distributions calculated on the basis of mixing various proportions of feed material with a ground material which obeys a power law size distribution relationship. Figs. la and lb illustrate such a comparison and the similarity of these figures indicates that mixing plays an important role in determining the overall shape of the product size distributions. Figs. la and lb illustrate, additionally, the underlying basis of the comminution theory presented by Schuhmann.' In the preliminary grinding of relatively close sized feed particles in a batch ball mill, one may visualize that, when a successful encounter of a ball with a feed particle occurs, then the particle undergoes severe size reduction and the size range in which the resultant particles reside is far removed from the size of the feed particles. After a number of feed particles are reduced by independent but similar impacts and one examines the size dis-

Jan 1, 1961

By George H. K. Schenck

Diminishing returns in management's fight to lower manufacturing expenses have added luster to savings that can be achieved in delivered costs through creative management of the distribution function. This is especially true for companies engaged in the production of bulk commodities, for which transport costs may represent 25 to 50% or more of total delivered price, A. E. Cascino, vice president of International Minerals and Chemical Corporation, recently gave an example of why top management in his firm is concerned with distribution: "The price of a ton of phosphate rock, f.o.b. mine, is about $7. The cost of warehousing, freight, and handling frequently totals an additional $11 . . . . If one of our competitors . . . discovers a way in which he can cut his distribution costs by $3, we're dead! Even if we wanted to offset our competitor's more efficient means of shipping with reduced f.o.b. price for our product-we don't have that much profit margin . . . ." In a special report on the revolution now occurring in transportation of goods, Business Week stated in its September 24 issue: "Moving and storing goods on their way from mine and mill through various sub-assemblies to their final markets costs anywhere from $50 billion to $75 billion a year- $100 billion if paperwork costs are included.

Jan 1, 1967

By P. L. Raffo, T. E. Mitchell

Single crystals of Ta-Re alloys have been deformed in tension and compression as a function of solute concentration and temperature. The temperature dependence of the yield stress is decreased by alloying. At low temperatures there is a minimum in the yield stress (at about 2 at. pct) as a function of concentration. Three-stage hardening was not observed in the alloys. Linear hardening rates, where observed, were characteristic of stage II in pure tantalum. At low temperatures and high concentrations, work softening was often prominent at high strains. Electron microscopy revealed that dislocations are mostly of screw orientation, although heavily jogged and cusped, and often occurring in dipole pairs. The alloys become more prone to cleavage with increasing rhenium content, due mostly to an increasing yield stress rather than a change in cleavage strength. Alloying apparently decreases the Peierls stress of bcc metals at low temperatures by facilitating kink nucleation at solule atoms on screw dislocations. Higher solute concentrations further increase the yield stress. Quantitative calculations and comparisons with other bcc alloy systems are made to show that the predominant hardening mechanism is due to the interaction of dislocations with misfitting solute atoms close to their slip planes. The interaction is so localized that the core dilatation of dislocations could be important. CONSIDERABLE interest has arisen in recent years concerning the mechanical properties of unalloyed bcc metal single crystals.'-7 These and similar studies on polycrystalline materials have resulted in a considerable understanding of the macroscopic yielding characteristics8, 9 and the process of work hardening.'' This latter advance is due in a large part to the increased use of transmission electron microscopy in P I RAFFO junior Membar AlMF is Metallyureist Iewis such studies and the general observance of three stages of work hardening in the shear stress-shear strain curves. The properties of substitutional alloy single crystals of bcc metals have not been determined in as much detail as in the pure metals. Insufficient systematic studies have been made on the effect of alloying on the magnitude and temperature dependence of the yield stress or the stress-strain curves. The alloy systems which have been studied to some extent have been Ta-W,11, 12 Ta-Mo," Ta-Nb,12'14 Mo-Re,15 W-Re,16 and alloys of iron with nickel,17 platinum,17 vanadium,18 and aluminum.18 A large body of data exists on Fe-Si alloys, but these have mainly been a result of the experimental convenience of using this material in place of unalloyed iron, rather than a comprehensive study of the mechanical properties of the alloy system per se. The present authors have previously reported additional data on the properties of Ta-Re, Ta-W, and Ta-Mo alloy single crystals.1g Some of the data on Ta-Re alloys will be described later in this paper. Briefly, single crystals of Ta-Re (1.2 to 10.6 pct), Ta-W (6.2 and 10.2 pct), and Ta-Mo (2.9 and 9.0 pct) were grown by the floating zone method in vacuum. Compression tests were performed in the temperature range 77" to 623°K. Slip was found to occur in Ta-Re alloys at 77' and 298°K on the (~ll)[lil] system and slip lines were coarser and straighter than in unalloyed tantalum. No three-stage hardening was observed in any of the alloy systems and the curves were nearly parabolic. At temperatures above 175°K the yield stress* increased monotonically with in- creasing composition while at 77" and 175°K the yield stress initially passed through a minimum after which it began to increase again for concentrations greater than about 2 pct Re. Similar minima were observed in Ta-Mo alloys and to a lesser extent in Ta-W alloys. The minimum was interpreted as being a result of a

Jan 1, 1969

By B. W. Frazier

At a recent meeting of the North of England Institute of Min ing and Mechanical Engineers, during a discussion upon the com pression of air, attention was called to an apparent anomaly in the phenomena attending the compression. At a subsequent meeting this apparent anomaly was explained by Prof. Herschel, and all the facts observed shown to be strictly in accordance with the laws of thermodynamics. Upon reading the report of the discussion in the published transactions of the society, it occurred to me that an attempt to determine mathematically the amounts of energy (whether in the form of heat or of work) expended and absorbed in compressing air, and causing it to perform work by expansion, might prove of use to some who have not access to any treatise upon the application of the laws of thermodynamics to the compression of air, and who have not the time or the inclination to make such application for themselves. The apparent anomaly noticed was this: If air be compressed, and at the same time, by the sufficient application of a cooling medium, kept at a constant temperature, the indicator diagrams in the

By Ravindra M. Nadkarni, Milton E. Wadsworth

The kinetics of cetnentation of copper with iron were observed to follow first-order kinetics and increase with speed of agitation to a limiting value. Maximum rates agree closely with theoretical values based upon a model of aqueous solution diffusion through a litniting boundary film. Back reaction kinetics are shown both theoretically and experimentally to be independent of ferrous iron concentration in solution. The inlportance of attnospheres of air, oxygen, nitrogen, and hydrogen was studied and the results have been correlated with several impovtant oxidation processes involving metallic iron and copper. The kinetics of the reaction of ferric ion with metallic iron were found to be slow in the absence of metallic copper and essentially proportional to the surface area of metallic copper present in the system. THE precipitation of copper on iron is classic as an example of a relatively ancient art applied successfully for centuries with little fundamental understanding of the important parameters involved. There is some indication that the process has been a commercial means to produce copper since the sixteenth century.' The amount of fundamental work on the cementation of copper with iron is not great. Wartman and Roberson2 carried out a series of detailed copper cementation experiments using natural and synthetic mine water. The following were presented as the three principal reactions: Reaction [I] is the desired cementation reaction and accordingly 0.88 lb of iron would produce 1 lb of copper. In actual practice iron consumption would more normally fall in the range of 1.5 to 2.5 lb per lb of copper. Wartman and Roberson attributed the excess consumption of iron to Reactions [2] and [3]. They found that Reactions [I] and [2] proceeded at approximately the same velocity while Reaction [3] was much slower and would be diminished by controlling the contact time. It was also pointed out that increased agitation is beneficial in removing hydrogen bubbles and barren layers of solution at the iron surface as well as removing contaminants resulting from the hydrolysis of iron. Episkoposyan3 and Episkoposyan and Kakovskii4 studied copper and silver cementation on rotating iron disks in chloride solutions. The kinetics based upon a diffusion model were first order and varied linearly with surface area and with angular velocity raised to the one-half power according to the Levich equation. The experimental activation energy for both copper and silver was approximately 3 kcal per per mole. Excess iron consumption was found to increase with temperature. The rate of cementation first increased with increasing acidity and then diminished at high acid concentrations. sutolov5 has presented an excellent review of the Leach-Precipitation-Flotation (LPF) process including a discussion of copper cementation from an electrochemical point of view although few experimental results were presented. From voltage considerations he predicted that cementation should not be influenced by the concentration of ferrous iron in solution. He considered several secondary reactions including Reactions [2] and [3] and pointed out the importance of oxidation of ferrous iron to ferric with oxygen. In addition it was suggested that Reaction [2] was enhanced by the dissolution of metallic copper by ferric iron which in turn consumed excess iron by the cementation reaction, Eq.[1]. Cementation of copper on metals other than iron has been studied by several investigators but, as in the case of iron, the amount of fundamental work is not extensive. Bashkova and kovalenko6 and Bashkova7 studied the cementation of copper on indium from copper and indium sulfate solutions. The rate was found to be first order and to increase with acidity. This was associated with a decrease in potential (EIn — ECu) and the simultaneous reduction of hydrogen ions at low pH. The rate of cementation also decreased with increasing indium concentrations which was postulated to be due to the decrease in the rate of diffusion of the ions in solution. Below 97°C the experimental activation energy was found to have the unusually low value of 2 kcal per mole and was attributed to diffusional control. Above 97°C the rate increased suddenly and was explained as a change in the rate-controlling step to a chemical reaction. In Part I of this study Nadkarni et a1 .1 have reported on preliminary results obtained in a laboratory study of the kinetics of the cementation process. The rate was found to be first order, proportional to the surface area of the iron, and to increase with speed of stirring until a maximum rate was observed. At low stirring speeds the deposit was spongy and adherent. At medium speeds the copper peeled off in bright strips and at high speeds finely divided copper was produced and continually removed from the surface. The amount of excess iron consumed increased with speed of stirring and with temperature. The average experimental activation energy combining results from several types of iron was 5.8 + 1.6 kcal per mole suggesting diffusional control through a limiting boundary film. Traditionally copper cementation has been carried out over the centuries in gravity-fed launders of various design containing scrap iron. More recently rotating drum precipitators and activated launders8'10 have been used. In the latter, copper-bearing solutions are

Jan 1, 1968

By C. D. Keen

IN the latter part of the summer of 1913 the Conservation Commission of the State of Louisiana, under presidency of M. L. Alexander, decided to stop the waste of natural gas going on at the "burning gas-well," located about 3/4 mile southeast of Oil City, La. On several occasions, both in newspapers and in reports, comment had been made on the condition of this well, its harmful effect on the Caddo gas field, and the considerable loss, estimated at several thousand dollars each month, caused by the escape of the valuable fuel. But nothing had been done to bring the well under control and prevent further waste of gas until the State Conservation Commission took the matter in hand. The gas fields of Louisiana are among the greatest in the country. So far most of the gas has been found in the Caddo field proper, although considerable development has been done in and around the city of Shreveport and near the town of Mansfield in DeSoto parish. To extend the life of the gas fields and to prevent the quick exhaustion of the supply of the natural fuel are matters of vital importance for this section of the country. Four gas companies have entered the Caddo field and supply the surrounding towns and cities with gas. The Arkansas Natural Gas Co. has pipe lines to Little Rock, Ark., and supplies gas to the following cities and towns in that State: Texarkana, Hope, Garland, Emmet, Prescott, Boughton, Beirne, Gurdon, Arkadelphia, Gum Springs, Malvern, Donaldson, Gifford, Perla,- Beaton, Beauxite, Mabelvale, Bryant, Sheridan, Pine Bluff, Little Rock, Argenta, Pulaski Heights, and Hot Springs. The Southwestern Gas & Electric Co. transports gas to Mooringsport, Blanchard, Caddo, Rodessa, Oil City, Vivian, Bloomburg, Hosston, Ida, Dixie, Belcher, and Shreveport. The Marshall Gas Co. supplies gas to the town of Marshall, Texas. The Louisiana Co. has a line to Shreveport.

Jan 3, 1914

By E. P. Klier

The work of Klier and Lyman1 on the bainite reaction has led to the full description of this reaction for medium-carbon low-alloy steels. Certain experimental data reported by Klier and Lyman appear, however, to be improbable of obtaining in very high-carbon steels. The study herein reported consists of an analysis of the transformation characteristics of a 3 per cent chromium, I per cent carbon steel by means of X-ray and metallographic methods. From the results obtained it is concluded that the bainite reaction in this steel is more complicated than that reported by Klier and Lyman for the low-carbon low-alloy steels. Henever, the mechanism of bainite formation in this steel appears to be essentially the same as proposed for the low-carbon low-alloy steels with the modification that the first volumes to transform are carbon-rich rather than carbon-poor. Experimental Procedure The analysis of the steel studied was: Cr, 2.89; C, 1.02; Mn, 0.33; Si, o.35; S, 0.012; P, 0.020. The stock was received from the Carpenter Steel Co. in rolled bars. Specimen Preparation Specimens were austenitized at 1200°C. (2192°F.) for 25 min. in purified nitrogen. The resultant A.S.T.M. austenite grain size was 0-1. Isothermal transformation was allowed by quenching the specimens into liquid metal baths controlled to 5°C. at 540°C. (1004°F.) and above, and to 2°C. at 490°C. (914°f.) and below. Following the desired degree of transformation all specimens were water quenched. Metallographic Examination Specimens 1/4 in. round by 1/4 in. were used for nietallographic examination. Etch-ants used were Vilella's reagent (I gram picric acid, 10 ml. hydrochloric acid to make 100 ml. ethyl alcohol solution) and alkalinc sodium picratc (electrolytic). Vilella's reagent was effective in revealing all microconstitucnts, while the alkaline sodium picrate developed the carbon-rich structures or carbides only. X-ray Examination Two X-ray techniques were used—the Debye-Scherrer method and a back-reflection method. 'The small specimens necessary for the Debye-Scherrer method were austenitized and then allowed to transform, or were cut from the larger metallographic specimens. The metallographic specimens were used for the back-reflection X-ray analysis. When it was desirable to determine the structure of the carbide present, sliver specimens were electrolytically etched to develop a carbide coating, then were exposed in the cameras. This technique was frequently necessary to allow positive identification of the carbide.

Jan 1, 1945

By E. P. Klier

THE work of Klier and Lyman1 on the bainite reaction has led to the full description of this reaction for medium-carbon low-alloy steels. Certain experimental data reported by Klier and Lyman appear, however, to be improbable of obtaining in very high-carbon steels. The study herein reported consists of an analysis of the transformation characteristics of a 3 per cent chromium, 1 per cent carbon steel by means of X-ray and metallographic methods. From the results obtained it is concluded that the bainite reaction in this steel is more complicated than that reported by Klier and Lyman for the low-carbon low-alloy steels. However, the mechanism of bainite formation in this steel appears to be essentially the same as proposed for the low-carbon low-alloy steels with the modification that the first volumes to transform are carbon-rich rather than carbon-poor. EXPERIMENTAL PROCEDURE The analysis of the steel studied was: Cr, 2.89; C, 1.02; Mn, 0.33; Si, 0.35; S, 0.012; P, 0.020. The stock was received from the Carpenter Steel Co. in rolled bars. Specimen Preparation Specimens were austenitized at 1200°C. (2192°F.) for 25 min. in purified nitrogen. The resultant A.S.T.M. austenite grain size was 0-1. Isothermal transformation was allowed by quenching the specimens into liquid metal baths controlled to ±5°C. at 540°C. (1004°°F.) and above, and to ±2°C. at 490°C. (914°°F.) and below. Following the desired degree of transformation all specimens were water quenched. Metallographic Examination Specimens 1/4 in. round by 1/4 in. were used for metallographic examination. Etchants used were Vilella's reagent (1 gram picric acid, 10 ml. hydrochloric acid to make l00 ml. ethyl alcohol solution) and alkaline sodium picrate (electrolytic). Vilella's reagent was effective in revealing all microconstituents, while the alkaline sodium picrate developed the carbon-rich structures or carbides only. X-ray Examination Two X-ray techniques were used-the Debye-Scherrer method and a back-reflection method. The small specimens necessary for the Debye-Scherrer method were austenitized and then allowed to transform, or were cut from the larger metallographic specimens. The metallographic specimens were used for the back-reflection X-ray analysis. When it was desirable to determine the structure of the carbide present, sliver specimens were electrolytically etched to develop a carbide coating, then were exposed in the cameras. This technique was frequently necessary to allow positive identification of the carbide.

Jan 1, 1945

By Samuel Hoyt

This paper gives a short account of plastic deformation as observed in single crystals of zinc, zinc having been selected for the experiments described herein because the phenomena are comparatively so simple and can be studied throughout such a wide range. It is hoped that the paper will serve to show the type of information which studies of single crystals afford and will contribute toward the solution of the general problem of metallic behavior. PRODUCTION OF ZINC SINGLE CRYSTALS The method of Czochralski,1 as modified by vow Gomperz,l was used to produce the crystals studied. The equipment is shown in Fig. 1. Molten zinc is held in a crucible at a temperature which is not far above its melting point, as measured by a pyrometer. A lava disc floats on the melt, and is provided with a central hole about 1 min. in diameter. A glass tube, drawn into a capillary at the lower end, is suspended from a string which is wound up by an electric drive at the speed desired. At the start, the glass capillary is let down into the melt and the hoist is started. The capillary brings up a small quantity of molten metal with it to a point just above the lava disc. At this point, a jet of hydrogen cools it and causes it to crystallize, with the result that a -small crystal forms. As the hoisting is continued, more molten metal is drawn up, in turn to be solidified by the jet of hydrogen. This additional metal continues the growth of the crystal already formed, and a long, cylindrical crystal results. The speed of hoisting used was generally between 0.1 and 0.5 mm. per sec., and the crystals were from 4 to 6 in. long and about 1 mm. in diameter. By varying the conditions, crystals of quite different orientations were obtained and were used in the study of the phenomena to be described.

Jan 1, 1927

By H. K. Work, H. B. Emerick

IN the past year the steel industry underwent an abrupt conversion from a war tempo to a highly competitive peacetime schedule. It is still too early to gain a comprehensive picture as to which of the measures in production metallurgy, that made the war effort so successful, will remain in the postwar production of steel, but many of them undoubtedly will fill an important place after the war. Considerable speculation has developed regarding the disposition of the war-born production facilities of the steel industry. These include new open-hearth and electric furnaces, as well as vast numbers of auxiliary, supplementary, and balancing units that increased and speeded up production beyond the normal capacities of existing melting furnaces and finishing mills. Although these facilities were installed primarily to help meet war requirements, consideration was also given, in planning, to their possible peacetime use. The new equipment is generally modern and efficient, and it seems reasonable to suppose that strategically located units will gradually be absorbed by various steel companies to supplement their own facilities, or to replace in kind, obsolete and inefficient equipment now ready to be scrapped. Some, however,

Jan 1, 1946

By Vernon Taylor

CANADA'S oil production is obtained almost entirely from the Turner Valley gas and oil field, in the Province of Alberta. This field, about 30 miles southwest of the city of Calgary and approximately 115 miles north of the United States border, supplied 92 per cent of production in Canada during 1937. In 1938 considerable development took place in this field and total production for the year amounted to 6,688,716 bbl., an increase of 3,922,146 bbl. over the production in 1937, which increased the percentage of production to approximately 97 per cent of Canada's total. In the British Empire, Canada's production is thus comparable to that of Bahrein Island and Burma, each of which produced approxi-mately 7,800,000 bbl. in 1937, being second to Trinidad's production of 15,500,000 bbl. The total production of the British Empire in that year amounted to 2.07 per cent of the world's total. HISTORY Development of the Turner Valley field commenced in 1913, when a well was started near a gas seepage on the banks of the South Fork of Sheep River in the central part of the Valley. This well found small quantities of a light crude oil in beds of Upper Cretaceous age and pre-cipitated a wild boom in 1913-1914 which ended with the beginning of the Great War in 1914. A small amount of drilling was done in the years from 1914 to 1922 and a few wells found small crude-oil production in the upper sands. In 1922 a few wells were started, including the Royalite Oil Company's No. 4 well (R, Fig. 1), which became the discovery well of naphtha pro-duction from the Paleozoic limestone. In October 1924, this well was completed at a depth of 3740 ft., being approximately 300 ft, in the lime-stone, with an initial flow of 600 bbl. of 72° A.P.I. gravity naphtha and 20,000 M cu. ft. of gas per day. Intense activity was not started until the latter part of 1928, when the Okalta No. 1 well (Q, Fig. 1) was drilled, with an initial production of 500 bbl. of naphtha per day. This well was only 1 ¼ miles from Royalite No. 4, but it was approximately 1300 ft.

Jan 1, 1939