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By R. V. Lundquist

Leaching manganese-bearing materials with NaOH to remove caustic-soluble silica has been demonstrated as a method for upgrading manganese. Those materials containing opaline varieties of silica respond most readily. Spent leach liquors are regenerated by treatment with lime to precipitate calcium silicate and to reactivate the NaOH for leaching. ALL of our larger domestic deposits of manganese are very low grade, but estimated tonnages in these deposits are large enough to constitute a potential strategic reserve of manganese for emergency periods, provided these ores can be upgraded sufficiently to meet industrial specifications. Many types of processes have been suggested for upgrading these ores, several have been studied in pilot plants, and a few have attained limited commercial production for special purposes. The hydrometallurgical process to be described below proposes a leaching operation for removing caustic-soluble silica and other gangue minerals and consequently upgrading a manganese ore or flotation concentrate to a commercially acceptable moduct. It is known that some forms of silica and some silicate minerals are soluble in NaOH solutions under suitable conditions. This new process proposes to use NaOH for removing the soluble materials from manganese ores or concentrates and, as a result, upgrade the manganese content. Since spent leach liquors are not efficient leaching agents the liquor must be treated with lime to precipitate calcium silicate and reactivate the NaOH. Experimental Procedure Manganese-ore samples ground to —35 mesh were leached in iron containers into which the ore sample and appropriate NaOH solutions were placed. Flotation concentrates were already ground to —200 mesh. The slurries were then placed on a hot plate or into a pressure digester and stirred continuously during the period of digestion. Where the- digestion was performed at atmospheric pressures, water lost by evaporation was replaced at regular intervals to maintain approximately a constant volume of slurry. In the pressure digester, volume changes were not controlled. After digestion, the slurry was allowed to cool enough for easy handling, but it was filtered hot, 50" to 70°C, on a Buechner filter. Filtration under these conditions was satisfactory. The resulting filter cake was washed and dried. In most instances, a single leach would not produce maximum extraction of silica from the ore sample; consequently, the dried tailing was treated again in the same manner with a fresh solution of NaOH to obtain an additional extraction of silica. This procedure was repeated a number of times to get the maximum extraction of silica. Usually three or at most four stages of leaching were adequate for this purpose. This leaching procedure was used for obtaining the data reported in this paper on the effects of NaOH concentration, pulp dilution, temperature, and time of digestion on the efficiency of extraction of silica from the ore sample. The experimental procedure does not match industrial methods. consequently tests for counter-current leaching were set up. Data from these tests are not yet complete, but in a qualitative way they indicate that thickeners between stages of leaching will be satisfactory and that the quantity of silica in a leach liquor moving forward to a new solid has only a minor effect on the quantity of silica extracted from the new solid. A pilot plant is now being designed for operation in the near future to test and evaluate the merits of this process.

Jan 1, 1954

By John Gjers

Being on a visit to your great and prosperous country, and having been favored with an invitation to attend this meeting of your Institute, the author has been requested by your Secretary to give a short account of his invention of the " soaking-pit," which he has great pleasure in doing. The object of the soaking-pit is the rolling of steel ingots with their own initial heat, that is, to supply the missing link in that chain of metallurgical operations which Sir Henry Bessemer began in 1857, when he proved how it was possible to produce malleable iron or steel direct from the fluid cast-iron out of the blast-furnace, without any further direct use of fuel. The great Bessemer invention has revolutionized iron and steelmaking throughout the world; but it stopped short at producing the ingot, which, it was found, had afterwards to be heated in a furnace to enable it to be rolled or hammered; and it is only lately, twenty-five years after Mr. Bessemer's announcement, that the author of this paper has been able to show that furnacing can be dispensed with, and that it is practicable to roll a steel ingot into say a bloom, a rail, or a billet, with its own initial heat. It has no doubt suggested itself to many that there ought to be heat enough in the ingot just cast, for the purpose of rolling; and from time to time attempts have been made to utilize this heat; but such attempts always ending in failure, it became a settled opinion in the trade that it could not be done—an opinion which the author is aware that your late lamented countryman, Mr. Holley, than whom there was none more conversant with Bessemer steel-making, also entertained. But settled opinions sometimes prove to be great fallacies. As an instance, it is not many years since the opinion prevailed in the trade that steel ingots could not be rolled successfully, that is, so as to make good rails, unless they were first allowed to get quite cold, and afterwards heated. No greater boon was ever conferred on the

Jan 1, 1885

By L. L. Davis

The rapid increase in the use of pulvcrulent adsorptive materials in the so-called "contact filtration" process for decolorizing lubricating oils makes it desirable to consider some of the basic principles involved. The commercial methods and types of equipment now used arc fairly well known, having been extensively described in the trade journals. In spite of this very little has been published concerning the factors which must be considered in the selection of a process or of a decolorizing ing material. It is commonly understood that contact filtration more or less closely follows the laws of adsorption. These principles have been thoroughly drscribed by Gurwitsch.' The contacting of neutral mineral oils seems to be adsorptive in character and apparently follows Freundlich's law of adsorption which may be expressed by the formula: X = Color material adsorbed hy the clay. M = Amount of clay used. C = Concentration of color material after equilibrium. A and P = Constants for a given oil and clay. Fig. 1 shows the decolorization curve for a natural, dark colored cylin-der stock when contacted with various quantities of clay, curve R being made with natural Riverside Texas fuller's earth and T being made with an acid-treated clay from Texas. As the Tag-Robinson color is inversely proportional to the depth of color, the reciprocal of these colors ran be assumed to be a funct ion of the concentratlion of coloring matter. The values of and C' can, therefore., br calculated by using the reciprocal Tag-Robinson colors, and when these

Jan 1, 1928

By T. R. Schermerhorn, Samuel L. Hoyt

The hardness of annealed copper has been given in the literature and is easily obtained by any of the standard methods of hardness testing. It is not our intention to correct published values or to add to them, but to describe tests of two bars of annealed electrolytic copper in which the methods of Meyer's analysis were employed. Meyer's Analysis of Ball Indentation Test The ball indentation test is probably the most valuable hardness test we now have but, as it is carried out in the Brinell or Rockwell test, the result may be seriously in error without the operator suspecting such to be the case. This condition results from the isolated and uncontrolled nature of the measurement. The accuracy depends on the accuracy of the equipment and the care and skill used in the operations; there is nothing in the impression diameter, which is all that is measured, to indicate the presence of error. Meyer's analysis supplies a control of the measurements that goes far toward eliminating unsuspected errors. The principles of this work may be obtained from elsewhere.' As this subject has not received the attention of this Institute, it may be well to summarize the more important points as follows. The chief difference between the usual ball indentation hardness test and Meyer's test is the use of a number of loads, instead of one, covering the range from small to large loads. The reason for this may not be obvious; the resistance to penetration may, and generally does, vary with the penetration of the ball; consequently a single determination can give only the resistance at that particular load. At some other load, the resistance may be quite different. For example, a test on annealed copper at 250 kg. gave a resistance to penetration of 39.5 kg. per sq. mm., while a similar test at 3000 kg. gave a resistance of 56.8 kg. per sq. mm. For the purpose of finding some figure that might be used to represent the hardness of the sample of copper, there is no reason for selecting one of

Jan 1, 1926

By J. M. Flaitz, A. S. Parks

OF the various methods of sampling gas-condensate wells, a method that secures a continuous representative sample of the well stream is desirable. Such a method, consisting of a sampling tube introduced into the well tubing, has proved satisfactory. The method is sufficiently accurate for operating and engineering problems A portable testing apparatus can be used with the sampling tube to obtain data useful in studying the economic and technical aspects of the development and operation of gas-condensate properties. Introduction The recent discovery and development of gas reserves that contain hydrocarbons that condense with reduction of temperature or Pressure, or both, to form a product known as condensate, has brought many new problems to the oil and gas industries. With further discovery of deep, high-pressure fields it is presumable that many more gas fields of this type will be added to the steadily increasing number. Such gas reserves are found either associated with oil as a gas cap or in separate formations. There seems to be no positive correlation between the physical or geological nature of the reservoir, and the chemical composition or phase characteristics of its contents. Knowledge of the chemical make-up and phase behavior of gas-condensate reserves is needed to cope with many problems. A knowledge of the chemical composition and phase characteristics of the reservoir material is necessary to properly design a gasoline or recycling plant, to estimate natural gas and condensate reserves, to enable the operator to study the economic and technical aspects of various methods of operation and development, and to carry Out the plan of operating subsurface and surface lease equipment. This information is often useful in questions of mineral ownership, proration, legal position, and taxation. It is the purpose of this paper to discuss methods used by the writers to determine the chemica1 composition and phase characteristics of the fluids produced from a condensate well. The scope of the paper includes a discussion and description of the method of sampling, the results of tests on the accuracy of the sampling method, a description of a portable testing apparatus used to examine the phase characteristics, typical results of tests on wells from several condensate fields, and some of the applications of these data to production problems. References to previous work on this subject are cited at the end of the paper. The Problem At reservoir conditions of temperature and pressure, the fluids produced from a condensate well exist in a homogeneous vaporous condition. The consequent reduction of temperature and pressure that occurs as this gas enters and flows up the well tube results in condensation of some of the hydrocarbon material to form a liquid. The relative amount of liquid condensed at any point in the flowing system

Jan 1, 1942

By J. M. Flaitz, A. S. Parks

OF the various methods of sampling gas-condensate wells, a method that secures a continuous representative sample of the well stream is desirable. Such a method, consisting of a sampling tube introduced into the well tubing, has proved satisfactory. The method is sufficiently accurate for operating and engineering problems A portable testing apparatus can be used with the sampling tube to obtain data useful in studying the economic and technical aspects of the development and operation of gas-condensate properties. Introduction The recent discovery and development of gas reserves that contain hydrocarbons that condense with reduction of temperature or Pressure, or both, to form a product known as condensate, has brought many new problems to the oil and gas industries. With further discovery of deep, high-pressure fields it is presumable that many more gas fields of this type will be added to the steadily increasing number. Such gas reserves are found either associated with oil as a gas cap or in separate formations. There seems to be no positive correlation between the physical or geological nature of the reservoir, and the chemical composition or phase characteristics of its contents. Knowledge of the chemical make-up and phase behavior of gas-condensate reserves is needed to cope with many problems. A knowledge of the chemical composition and phase characteristics of the reservoir material is necessary to properly design a gasoline or recycling plant, to estimate natural gas and condensate reserves, to enable the operator to study the economic and technical aspects of various methods of operation and development, and to carry Out the plan of operating subsurface and surface lease equipment. This information is often useful in questions of mineral ownership, proration, legal position, and taxation. It is the purpose of this paper to discuss methods used by the writers to determine the chemica1 composition and phase characteristics of the fluids produced from a condensate well. The scope of the paper includes a discussion and description of the method of sampling, the results of tests on the accuracy of the sampling method, a description of a portable testing apparatus used to examine the phase characteristics, typical results of tests on wells from several condensate fields, and some of the applications of these data to production problems. References to previous work on this subject are cited at the end of the paper. The Problem At reservoir conditions of temperature and pressure, the fluids produced from a condensate well exist in a homogeneous vaporous condition. The consequent reduction of temperature and pressure that occurs as this gas enters and flows up the well tube results in condensation of some of the hydrocarbon material to form a liquid. The relative amount of liquid condensed at any point in the flowing system

Jan 1, 1942

By Will H. Coghill, J. Bruce Clemer

Flotation has been so closely allied with the sulfide minerals and their early and associated oily reagents that the term "oil flotation" has erroneously been applied to the entire flotation process. Today, the term "chemical flotation" might be used to advantage. Flotation literature has dealt primarily with the removal of sulfides from non-sulfide gangues, and the separation of one sulfide from another. Now, the application of the process to the separation of nonsulfide minerals is coming to the fore; and from the standpoint of the number of commercial minerals involved, the flotation of nonsulfides offers the larger field. Here, soap or soap-forming substances, such as the fatty acids and their derivatives, are used; hence there may well be a subdivision of the chemical flotation process called "soap flotation." Early experimenters learned that it was easy to form a froth or foam that would carry a part or all of the ore charge over the lip of the flotation machine; but this could not be regarded as flotation because of the lack of selectivity. Doubtless soap was one of the first reagents tried, and doubtless it was rejected on account of its gangue-carrying properties. Now this same gangue-carrying ability makes soap an acceptable reagent, for we are dealing with that which, among sulfides, is considered "gan-gue." As in the flotation of sulfides, so in the flotation of nonsulfides, the selective flocculation of the mineral and the dispersion of the gangue are the first objectives. In fact, these two phenomena epitomize flotation. They depend upon the unlike surface properties of the respective minerals; and as long as the components of an ore have unlike surface properties, a separation is possible, at least in theory. Often in nonsulfide flotation it makes little difference which mineral floats and which is depressed; generally only a separation is sought.

Jan 1, 1935

By Walter Crafts, C. M. Offenhauer

In a previous study of the carbide phase of chromium steels, it was shown that chromium carbide (Cr7C3) is 2 more stable carbide than cementite (Fe3C) at tempering temperatures above about 500°C. in quenched steels containing from about I to 7.5 per cent chromium. Below this temperature the carbide phase was found to consist of cementite in all of the steels examined. In the present investigation it was found that a similar change in the carbide phase takes place in molybdenum and in chromium-molybdenum steels at approximately the same tempering temperatures. The approximate ranges of occurrence of the alloy carbides Cr7C3, Cr4C, and Mo2C have been determined in steels containing up to 5 per cent chromium, I per cent molybdenum and 0.60 per cent carbon. The experimental steels were made in small high-frequency furnaces from Armco ingot iron, low-carbon ferrochromium and calcium molybdate and were poured into 2-in. ingots, which were forged to I-in. round bars. Sections of the bars were heated to the carbide-solution temperature and cooled rapidly to induce austenite transformation at relatively low temperatures. The steels were subject to some segregation, therefore comparatively high temperatures were necessary to dissolve all of the carbides. The microstructure of the quenched specimens was examined to verify the belief that the carbides had been dissolved, and also to determine the nature of the nonmartensitic structure of incompletely hardened steels. Ferrite and pseudo-martensite were present in some of the specimens, but all specimens were quenched at such a rate that pearlite was not formed, in order to ensure the formation of the carbides at temperatures lower than about 500°C. It had been found previously1 that in chromium steels the chromium carbide could be produced by transformation of austenite in the pearlite range above 500°C., and, in order to start the tempering treatment with the carbide present as cementite, the absence of pearlite was considered to be essential. The specimens were tempered for 64 hr. to permit the formation of the stable carbide. After tempering, the specimens were submitted to microscopic and X-ray examination. The carbides were separated either electrolytically in a 5 per cent HCl electrolyte or with an acidified copper-potassium chloride solution. The crystal structure of the carbide phases was determined by the Debye-Scherrer type of X-ray patterns. The X-ray patterns obtained from specimens near the boundaries between two types of carbides were generally weak and diffuse as compared with the other patterns. For this reason, and because the more soluble components may be masked, the boundaries between the phases could not be determined precisely. However, the X-ray analysis of electrolytically separated carbides has given consistently reproducible results

Jan 1, 1943

By Walter Crafts, C. M. Offenhauer

In a previous study of the carbide phase of chromium steels, it was shown that chromium carbide (Cr7C3) is 2 more stable carbide than cementite (Fe3C) at tempering temperatures above about 500°C. in quenched steels containing from about I to 7.5 per cent chromium. Below this temperature the carbide phase was found to consist of cementite in all of the steels examined. In the present investigation it was found that a similar change in the carbide phase takes place in molybdenum and in chromium-molybdenum steels at approximately the same tempering temperatures. The approximate ranges of occurrence of the alloy carbides Cr7C3, Cr4C, and Mo2C have been determined in steels containing up to 5 per cent chromium, I per cent molybdenum and 0.60 per cent carbon. The experimental steels were made in small high-frequency furnaces from Armco ingot iron, low-carbon ferrochromium and calcium molybdate and were poured into 2-in. ingots, which were forged to I-in. round bars. Sections of the bars were heated to the carbide-solution temperature and cooled rapidly to induce austenite transformation at relatively low temperatures. The steels were subject to some segregation, therefore comparatively high temperatures were necessary to dissolve all of the carbides. The microstructure of the quenched specimens was examined to verify the belief that the carbides had been dissolved, and also to determine the nature of the nonmartensitic structure of incompletely hardened steels. Ferrite and pseudo-martensite were present in some of the specimens, but all specimens were quenched at such a rate that pearlite was not formed, in order to ensure the formation of the carbides at temperatures lower than about 500°C. It had been found previously1 that in chromium steels the chromium carbide could be produced by transformation of austenite in the pearlite range above 500°C., and, in order to start the tempering treatment with the carbide present as cementite, the absence of pearlite was considered to be essential. The specimens were tempered for 64 hr. to permit the formation of the stable carbide. After tempering, the specimens were submitted to microscopic and X-ray examination. The carbides were separated either electrolytically in a 5 per cent HCl electrolyte or with an acidified copper-potassium chloride solution. The crystal structure of the carbide phases was determined by the Debye-Scherrer type of X-ray patterns. The X-ray patterns obtained from specimens near the boundaries between two types of carbides were generally weak and diffuse as compared with the other patterns. For this reason, and because the more soluble components may be masked, the boundaries between the phases could not be determined precisely. However, the X-ray analysis of electrolytically separated carbides has given consistently reproducible results

Jan 1, 1943

By G. W. Tuffnell, S. Floreen

Three Fe-18 pet Ni-base ternary alloys cortaining carbon, molybdenum, or cobalt were aged to pgroduce hardening by carbides, Ni3Mo, or ordering, respectively. Each alloy was tested in rotating-beam fatigue tests after hardening to 195 ksi ultim.ate tensile strength. The fatigue properties of three alloys soere essentially identical. The results suggest that tlze fatigae strength of an igron-base alloy should depend primarily upon the tensile strength, and not iipon the hardening mecaanisrn. THE fatigue strengths of many steels have been found to be directly related to their ultimate tensile strengths. For ultimate strengths below 200 ksi, the fatigue endurance limit at 107 to 10' cycles is approximately half the ultimate strength. Essen- tially all of the steels that have been tested, however, have been hardened by carbon. Thus it is not certain whether the relationship between fatigue and ultimate strengths is a general one that applies for other types of hardening in steels, or whether it applies only for the particular method of hardening by carbon. The recent developments of the martensitic precipitation-hardened stainless steels and the marag-ing steels have shown that it is possible to achieve high strengths in iron-base alloys by other hardening mechanisms than that due to carbon. Therefore, it is now possible to compare the fatigue properties of several iron alloys having the same ultimate strengths but hardened by different mechanisms. For the present study a binary Fe-18 pct Ni martensite was selected as a base material. This particular matrix composition has been found to have deformation characteristics very similar to pure iron.' Three ternary alloys were prepared by adding either 0.23 wt pct C, 5 wt pct Mo, or 20 wt pct Co to this base composition. After suitable heat

Jan 1, 1965

By Oscar A. Glaeser

THE mine and plant of the United Verde Copper Co., located in Yav-api County, at Jerome, Arizona, have been described in various technical publications and, therefore, a brief outline of its essential features will suffice. The orebodies are of the schist replacement type, the main sulfide mass being a large lens-shaped body approximately 7 acres in cross-sectional area. In general, the mineralization is found along the iron-schist contact, with the orebodies extending about 1000 ft. along this contact and varying from a few feet to 250 ft. in width. The mine is located on a mountain slope and has openings into it on three horizons, as follows: 1. Raises and ore passes open vertically into the shovel pit. These extend down to the 1000-ft. level, where they terminate as loading bins in the Hopewell adit. The main fan intake air shaft, which also extends vertically down to the 1000-ft. level, has its surface opening on the hillside at the extreme north end of the shovel pit, and the main mine air return exhausts through a raise at the extreme south end of the shovel pit. 2. The 500-ft. level adit. 3. The Hopewell adit on the 1000-ft. level. The mine has a vertical downward extent of 2000 ft. below the 1000-ft. level. Underground operations are carried on through two main shafts, both of which are wholly underground. Shaft 5 is the ore-hoisting shaft. It has three compartments and extends from the 800 to the 3150-ft. level. Shaft 6 is the service shaft, and is used for lowering and hoisting men and material. It has a large cage compartment and three smaller compartments for counterweights, ladderway, and pipe and power lines. This shaft extends from the 500 to the 2550-ft. level, and is now being extended to the 3000-ft. level. An air shaft for the downward movement of fresh air from the fan has been provided, and extends to the 2550-ft. level at this time. Work has been started to extend this air shaft to the 3000-ft. level. A return airway for vitiated mine air, in the form of raises and short connecting drifts, extends downward to the 2100-ft. level. The underground mining operations extend from the 300 to the 3000-ft. level. There are about 45 stopes in active operation on the 17 levels

Jan 1, 1929

By J. O. Brittain, N. R. Adsit

It has been suggested that grain boundary motion during creep is a two-stage process, i.e., sliding followed by migration. Wienbergl found alternate sliding and migration of aluminum tricrystals tested in shear. He concluded that curves of grain boundary sliding (G. B. S.) vs time were not reproducible from specimen to specimen. Couling and Roberts,' who worked on polycrystalline magnesium, found that sliding and migration were interdependent. They were able to correlate the amount of sliding with the number of sliding-migration cycles, i.e., the amount of migration observed metallographically. Rhines, Bond, and Kissel found that the curves of grain boundary sliding vs time were spasmodic but they did not find any migration of the boundary. Some recent creep tests on bicrystals of high-purity zinc (99.99 pct) help to elucidate the role of grain boundary migration in the G. B. S. process. The experimental technique and apparatus are described elsewhere. The tests were conducted in vacuum or a protective atmosphere of argon. All specimens were stressed in simple shear along

Jan 1, 1961

By Waldemar Lindgren, Clyde P. Ross

To the miner, as well as to the geologist, the eastern part of Cuba is a most interesting region. Here we find, in contrast to the moderate relief predominating elsewhere in the island, an imposing mountain range, the Sierra Maestra, extending east and west parallel to the coast, its precipitous front facing the blue Caribbean Sea. In a geological sense this range is largely an unknown land, the only well-explored region being that in the vicinity of Santiago. The range also contains the most important mineral deposits of the island. They comprise, first, a series of iron deposits yielding a partly hematitized magnetite with low content of phosphorus; second, a remarkable copper-bearing vein at El Cobre; and third, various manganese deposits. Probably more deposits will be found, for the larger and western part of the range is as yet little explored and its slopes are covered by a thick tropical jungle. The following notes are based on a short visit by the senior author in January and February of 1914 to the mines at Daiquiri, El Cobre, and Mayari. For many courtesies and great assistance he is deeply obliged to Charles F. Rand, President of the Spanish-American Iron CO.; to George W. Pfeiffer, General Manager, and to the several members of his staff. Geological Features of the Sierra Maestra For our knowledge of the geology of the Sierra Maestra we are indebted to reconnaissance work by Fernandez de Castro, R. T. Hill, Mr. C. Hayes, T. W. Vaughan, and A. C. Spencer. The summary by the latter three geologists furnishes the best guide to the region.' The range is undoubtedly outlined by a great east-west dislocation. Its southern slope drops abruptly to the sea, while on the north side a much gentler declivity leads down to the rolling plateau of Tertiary limestone which occupies much of the adjacent part of the island. Viewed

Jan 1, 1916

By Earl S. Greiner, Bradley Stoughton

As a part of the systematic study of the alloys of iron under the auspices of the Engineering Foundation, and preliminary to the commencement of comprehensive work on this larger subject, the authors have undertaken an investigation of the available literature dealing with the alloys of iron and silicon. The purpose is to collect all the data in English and foreign languages and present them in two monographs, one of a more scientific and the second of a more industrially useful nature. Of course, a great deal of information upon the constitution of the iron-silicon alloys was found specificially upon the changes of phase in the equilibrium diagram and the different phases present, such as solid solution, chemical compounds (iron silicides), etc. While no extended research was contemplated in the particular study undertaken, nevertheless the data collected proved to be so contradictory in many respects that a simple study of some of the outstanding problems involved in the constitution and equilibrium diagram was undertaken. Because research was not a primary object of the work, and also because of the extreme industrial importance of the silicon alloys between 0.80 and 14 per cent. silicon, and finally because of the unsatisfactory state of knowledge existing as to these alloys, the experimental investigation was limited entirely to alloys with less than 10 per cent. silicon. Discussion oF Continuous Series It has often been said in print that the iron-silicon alloys form a continuous series of solid solutions from 0 to 15 per cent. silicon. This claim the authors are inclined to doubt: first, because the alloys from 0 to 4.25 per cent. silicon are ductile and malleable at atmospheric temperature, while those with 5 per cent. or more of silicon are comparatively hard and brittle. Furthermore, the alloys with more than 4.25 per cent. silicon are comparatively hard and low in ductility at atmospheric temperature, but become much more ductile when heated slightly. It is well known, for example, that the alloy containing 4.75

Jan 1, 1930

By Albert H. Fay, William B. Plank

In practically all rock-excavation problem there is need for a careful study of the rock structure, its fault, cleavage or bedding planes, and even the texture of the rock itself. These studies should form the bases upon which an excavation method is selected and they should be carefully considered in predicting the amount and extent of the excavation. The need for such studies was forcibly illustrated in the problems involved in a cut made in 1929, along and underneath a 200-ft. high rock projection for a State highway near the City of Easton, Pennsylvania. The rock mass was badly faulted and also contained a number of cleavage planes at approximately right angles to the fault planes. Much of this structure was visible and could have been studied and analyzed before the work was begun. The State had rigid specifications as to finished grade and slope of cut, which apparently were made without reference to the geologic structure. The contractor complied with the specifications, under the close inspection of the State engineers. A tunnel blast was placed in the base of the cliff, with the result that 65 per cent more rock was broken than was intended by the specifications. About four years after the blast, the writers of this paper studied the circumstances surrounding the operation, to determine the cause of this excess excavation. Scope of Work The section of the roadway involved was about 200 ft. long and on a 6' curve. It was necessary to relocate points on the curve, from which all faults and cleavage planes were located and measured by the use of transit and clinometer. A plan (Fig. 1) showing the blasting tunnel, the roadway, and traces of the faults and cleavage planes on the level of the roadway, was prepared; also 13 cross-sections at varying intervals, showing the original face of the hill and the face after the blast. The original and final profiles of the rock face, taken from the plans of the State engineers, are shown in Figs. 2, 3 and 4.

Jan 1, 1937

By Wilford L. Stork

Certain influences of oxygen on iron have been known for many years and it has always been considered one of the worst enemies of the iron and steel founders. Nobody had a good word for it, hence little was done to make use of this oxygen. In all the fields of foundry practice, the desideratum was "melt without oxidation of the metal." In the consideration of the influence of oxygen on cast iron, we must not confuse this condition with oxidized iron caused by poor melting conditions, due to a high bed, heavy charges, low coke ratio, excessive melting rate, high blast, or poor charging. It is admitted that oxygen absorbed by iron melted under these conditions has a deleterious effect on the properties of the iron. The writer has had experience both in the melting under such poor conditions and in remedying these bad conditions and considers the product far inferior to iron melted under normal conditions. As stated by Dr. Richard Moldenke,l such iron has a higher melting point and high combined carbon, is sluggish, and contains slags and oxides in solution in the liquid, causing slag inclusions and gas occlusions, 'thus producing defective castings. This oxidized condition cannot be counteracted or removed by any of the known deoxidizers; it can be remedied only by proper melting conditions. Such iron is redly burned, whereas the iron considered in this paper was melted under normal conditions with moderate blast, correct bed height, light charges of iron, and low coke consumption and is not in this category at all. In 1914, the late J. E. Johnson, Jr., startled the metallurgists of the . world when he published his results on the advantages of oxygen on cast iron.2 His work is so convincing and so logical, in spite of the common and well-established notions on the subject, that nobody has been able to refute a single argument. Such an eminent authority on iron and steel metallurgy as Prof. H. M. Howe has accepted the work in all its details in his latest book.3 The work of J. E. Johnson, Jr., has revolutionized the metallurgy of cast iron and it seems apparent that all future work must include an oxygen determination just as we include silicon, sul-

Jan 1, 1920

By Frank Foote, V. H. Nordstrom, Eric R. Jette, Bernard Queneau

The nickel-chromium alloys form the base for many industrial heating alloys, so that this system is of considerable practical importance. The literature on these alloys, however, contains much conflicting evidence, not only regarding the solubility limits of the terminal solid solutions at different temperatures but even regarding the number of phases existing in the system. Part of the difficulty undoubtedly arises from the fact that chromium of sufficiently high purity has been available only during the last few years. A second and possibly even more important difficulty arises from the ease with which chromium reacts with silicon and carbon compounds and the atmosphere to form silicides, carbides, nitrides and oxides. Pilling and Kihlgrenl in 1929 reviewed the existing scanty information. They did not consider the diagram by which they summarized the various bits of information to be entirely satisfactory. Matsunaga2 investigated the system by thermal analysis, microscopic examination and other means. Electrolytic nickel of 99.9 per cent purity and thermit chromium containing 0.30 per cent Al, 0.40 per cent Fe, 0.25 per cent Si and 0.04 per cent C were used. A Tammann furnace with hydrogen flowing through it was used for melting. Sekito and Matsunaga3 reported an X-ray investigation, presumably on these same alloys, which, as far as can be judged from the abstract, essentially confirmed the thermal and microscopic results. Nishigori and Hamasumi4 found compositions for the terminal solid solutions in equilibrium at the eutectic temperature which agreed fairly

Jan 1, 1934

By C. H. Wilson, J. W. Daly, J. J. Jakosky

Meteor Crater, Arizona, is a natural wonder which for years has been the subject of considerable discussion and study as to its origin and age (Fig. 1). Of the various theories advanced regarding the origin, two have been considered as most probable by a majority of investigators. The first theory is that the crater was formed by a meteorite or a swarm of meteoric material striking the earth at a high velocity and burying itself. The second theory is that the crater was formed by a "steam explosion" from hot solutions or gases coming from underneath the present sedimentary beds which overlie the area. In order to obtain more detailed information regarding the conditions existing at the crater, the present management decided to have a detailed geophysical examination made. The origin of the crater is of considerable scientific importance and interest. More or less active mining operations have been carried out during the past 20 years by various groups who believed that the crater was of meteoric origin, and who hoped that sufficient quantities of such material had been buried to be commercially valuable. Fragments of meteoric material found on the surface of the ground in the debris around the rim gave analysis of approximately 92 per cent iron and 8 per cent nickel, with some platinum and iridium. The material having a gross value of approximately $50 per ton, mining would be commercially profitable if sufficient quantities of the material existed in condition for mining. In the early work numerous drill holes and shallow shafts were put down, mainly in the northern portion of the crater. Pulverized material and debris caused considerable difficulty, and in an effort to overcome this the present management started a 1500-ft., two-compartment shaft on the south rim of the crater and outside of the fill zone. The intention was to sink the shaft in the solid rock outside of the crater, and then to crosscut toward the crater at a depth of 1500 ft. The work was finally stopped when a depth of 650 ft. was reached, because water poured into the shaft through large cracks and fissures in the rock. The enormous force responsible for the crater had also broken

Jan 1, 1932

By Peter G. Tregelles, Derek K. Barham

Introduction A successful step towards mechanisation of the collier's work was taken in 1954 when the first Anderton shearer loader was commissioned in Lancashire, and progress was reinforced in 1956 when the first powered supports were installed in Nottinghamshire. By 1970, virtually 100% of the coalfaces in the United Kingdom were mechanised and the industry's productivity had doubled. In 1961 the National Coal Board recognised that the next move towards greater productivity and improved safety would be to automate the longwall system. What was not well enough understood, however, was that the basic prerequisites of automation - reliability and measurement - had not yet been achieved. Consequently, the schemes for automatic longwall faces and for an entirely automated colliery were abandoned at the close of the decade. A review of mining research and development policy, commissioned by the Board in 1974, confirmed that the system of longwall mining had great potential for investment and that the short-term policy of automation must once again be pursued. Since then, aided by advances in computer technology, systems for automating the transport of coal from the face to the coal preparation plant have been successfully instituted. Applications of sub-systems dealing with the conveyor, coal preparation plant, and various items of fixed plant are now at the exploitation stage. In the medium term, a number of key problems have been identified, which will arise once the productivity from the coalfaces has doubled, as it is now expected to do in the next five years. One of the most important of these problems is machine guidance, and considerable research and development work is now being carried out in this area. This paper reviews the work on machine guidance prior to 1974 and explains the programme on which the National Coal Board's Mining Research and Development Establishment is currently working.

Jan 1, 1981

By AIME AIME

WITHOUT frills, but with an admirable program of technical papers and discussion, many opportunities for social contact, and all New York for a playground, the 142d Meeting of the Institute will make the Engineering Societies Building a lively place from Feb. 20 to 23. Prices are down, even in New York. Come and forget the depression listening to the stories of old friends. Hear at first hand what is going on in your professional world. The fare is varied, of wide appeal. The program on the opposite page has been arranged carefully to minimize conflicts between the subjects in which you are interested. If it is not possible to come for all four days, check over the sessions that are most important to you. No changes in the scheduling are likely.

Jan 1, 1933