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By C. A. Heiland

GEOPHYSICAL methods are playing an ever increasing part in various engineering fields. About ten years ago, geophysical exploration was first applied in civil engineering to the study of foundations and the location of construction materials and water. Its usefulness is now being extended into the field of structural engineering. Almost every structure has to be so designed that it will withstand any force to which it may be subjected. Such forces may result from its own weight, applied loads, pressures of various kinds, including those due to wind and water, ground subsidence and vibrations. The last two, problems involving the nature and dynamic behavior of surface and subsurface formations, are within the scope of geophysical investigations. In the design of any structure, the disposition and dimensions of its members as well as their materials must be so selected that they will withstand any or all of the forces enumerated above. In other words, its "resistance" to such forces must be sufficient, allowing for a definite margin of safety. Often a static treatment of the problem leads to satis-factory results, but the static method entails serious errors when vibra-tions are involved, as in resonance with an impressed vibration the displacements of a structure or parts thereof may dangerously exceed the allowable values. The principle of "dynamic design"? is, therefore, avoiding or reducing resonance by suitable selection of the natural frequency of a structure, or by the provision of damping.

Jan 1, 1939

By W. C. Maurer

Although millions of feet of rock are drilled annually, the basic drilling mechanisms involved are not well understood. The primary reason for this lack of knowledge is because the basic principles of rock failure are not well understood and rock failure is the primary mechanism in drilling. A better understanding of the drilling mechanisms would enable a more scientific approach to the design and use of drills and bits. The paper reviews several models which have been proposed to explain various aspects of the different drilling methods. These models are described and their limitations and areas of application are discussed. Drilling rate relationships are developed and related to the basic rock failure mechanisms. TYPES OF MECHANICAL DRILLS There are three basic methods of mechanically attacking rock: 1) percussive action, 2) rotary action, and 3) combined rotary-percussive action. A percussion drill applies a force perpendicular to the rock surface and the bit moves into the rock perpendicular to the surface, forming a crater beneath it (Fig. 1). A rotary drill applies a constant thrust to the bit while a torsional force moves the bit parallel to the rock surface, breaking the rock ahead of it. A rotary-percussive drill applies both a rotary force and a percussive force to the bit which moves into the rock at an angle to the surface. The commonly used drills can be classified as: rotary-drag, diamond; percussive-hammer, piston, churn; and combination-rotary-percussive, roller.

Jan 1, 1967

By Robert Corcoran, George Wiener

A study of the orientations and microstructure of 3 pct Si Fe alloys after deformation and recrystallization has been made. The components found after deformation agreed with recently published work on single crystals, being primarily (001) [110], (111) [110], and (111) {112}. A pronounced effect of temperature of recrystalliza-tion was found on microstructure and orientation. Low temperature recrystallization was interpreted in terms of low angle boundaries which resulted in the retention of a large amount of the deformation texture. High temperature recrystallization was interpreted in terms of high angle boundaries which gave rise to new components. No simple angular relation between the deformation and high temperature recrystalliza-tion textures could be detected. DEFORMATION and recrystallization behavior of 3 pct Si-Fe has been the subject of scientific investigation for many years. The fact that it is a single phase body-centered-cubic alloy from room temperature to the melting point permits study over a wide range of temperature without the complications of phase transformations. There is an important commercial interest in this material as well, since it is widely used in the electrical industry. In the present work the deformation and recrystallization behavior of poly crystal line silicon iron has been studied with the primary purpose of evaluating the effect of a second phase impurity on both processes as well as the effect of temperature on the recrystallization characteristics. With regard to deformation, the emphasis has been placed on a study of the crys-

Jan 1, 1957

By A. N. Winchell

Petrographic studies of over 1400 rock and mineral samples, and studies of their field relations, show that there is a complete gradation between sandstone and limestone; the lime-silicate rocks were produced by recrystallization of limestone; mineralization and silicification occurred after silication and at considerably lower temperature; carbonation occurred at still lower temperatures. IN CONNECTION with law suits between mining companies at Bingham, Utah, a few years ago, the writer made petrographic studies of more than 1400 rock and mineral samples in thin sections, and also careful studies of their field relations. In petrographic studies, even when an area is studied intensively, attention is commonly centered very largely on the unusual features of special interest, so that the relative abundance of rock types (or minerals or textures) can only be determined by a study of map areas outlined largely by field methods, and cannot be based directly on microscopic work. It is very uncommon, and usually impossible, to take samples at regular short intervals along and across formations. It is precisely because such methods were used at Bingham that the work presents a rare opportunity for determining, on a microscopic basis, the relative abundance of rock types and the continuity of gradations between rock types. At the same time, a study was made of the alteration of sediments under the influence of igneous intrusions, with results that are believed to be of interest and importance.

Jan 3, 1924

By G. B. Craig, J. Rezek

The critical resolved shear stress of zone-refined zinc single crystals deformed in tension is found to increase with increasing amount of striation substructure. The increase in strength with numbers of striations can be accounted for by a dislocation pile-up mechanism. A somewhat different means of plotting stress-strain data is introduced which allows a more unambiguous choice of yield stress to be made. FEW systematic studies of the role played by mac-romosaic or striation-type substructure in the de- formation of high-purity metal single crystals grown from the melt have been reported. McGrath and Craig' found that striations increased the critical resolved shear stress of zone-refined aluminum crystals, postulating a dislocation blockage by the striations as the strengthening mechanism. Lauri-ente and Pond2 found that, as the etch pit density increased in aluminum crystals grown from the melt, the critical resolved shear stress also increased. Fleischer and Chalmers3 also found changes in the critical resolved shear stress of aluminum crystals grown from the melt at varying rates, but could not be certain whether an increase of strength with rate was due to a higher concentration of impurity in the gage length or to an increase in the number of small-angled boundaries. An early work by Hibbard4 indicated that copper crystals containing lineage boundaries were stronger than those free from this type of imperfection.

Jan 1, 1962

By W. R. Crane

The effect of mining in the red-ore mines of the Birmingham district has been observed for some time, but, except in a few localities, little difficulty has been experienced from disturbance of cover. Cave-ins near the outcrop and fracturing of the surface at greater distances are the most pronounced manifestations of disturbance, while limited areas at points distant from the outcrop and under greater depth of cover have actually subsided. were it not that the orebed is overlain by one or more water-bearing formations, the fracturing or settlement of the surface would not be serious; but because of these formations, fracturing of the top rock may in itself be of sufficient importance to warrant the adoption of protective measures. Further, the collapse of pillars over a wide area may develop squeezes that, if not controlled, may jeopardize the integrity of the mines and necessitate a change in development, from slopes to vertical shafts, at a much earlier period than is now contemplated. Drainsge in these mines has been discussed in papers on mining practice,' but the fact that water, varying from 0.16 to 3.46 and averaging 1.43 times the amount of ore mined, has to be pumped from the mines daily, indicates the importance of the problem and the advisability of making a thorough investigation of the source of mine water, its mode of entry into the mines, its effect upon mining conditions, and consideration of means of improving the conditions.

Jan 1, 1927

By Arthur Knapp

The practical application of mud-laden fluids in wells has been the subject of many papers.' However, there seems to have been little investigation of what actually happens when mud-laden fluids are applied to a loose porous sand. The assumption is that the fluids penetrate the sands and that there is some plastering action. The degree of penetration and the relation of plastering action to wall stability is not generally known. This paper describes a series of experiments made in an attempt to observe, in laboratory apparatus, the action of mud-laden fluids under conditions simulating those to be found in a well. For the purposes of this discussion all fluids containing solid matter in suspension are mud-laden fluids. Series I: Penetration of the Pores of Uncemented Sands The subject of the penetration of porous formations by water is discussed in detail in Water-Supply Paper No. 67 of the U. S. Geological Survey. No attempt was made to repeat the experiments described therein. The results of the first experiment of this series are given simply to show the capacity of the apparatus used. The conditions in this first experiment were maintained throughout the remainder of this and the second series, except where noted. The experiments of Mills, McCoy, and others on subsurface flows, adjustments, migrations, etc., deal with the oil, water or gas within the porous beds.V he experiments described herein deal with the conditions immediately surrounding the bore hole.

Jan 1, 1923

By Charles Barrett

THE experiments reported in this paper have been fruitful in disclosing the mechanism of the deformation of iron in compression. They have established the nature of "deformation bands," "etch bands," or "X-bands," that have been a recognized but little understood feature in the structure of cold-worked metals since the early days of metal-lography, and have shown the role of the bands in the development of preferred orientations by cold-working. The work has also shown the relation of the orientation of individual grains to the preferred orientation of the aggregate. Some of the methods previously used in the determination of the indices of slip planes and slip directions are shown to be untrustworthy in the presence of deformation bands. The conclusion is reached that many slip planes and slip directions must operate during each stage in the compression of a single crystal, and that theories failing to take account of this require revision. In conducting the experiments a method f compression has been used by which extreme reductions can easily be reached, even to the limit set by the metal's capacity to deform with-out fracture. The work is a portion of a research program on the plastic properties of iron and steel. It is being used as a foundation for studies of orienta-tions resulting from recrystallization and is being extended to other metals and other types of deformation.

Jan 1, 1938

By Alexander Field

INTRODUCTION THE Bureau of Mines is investigating the problem of slag viscosity, its variation with the temperature and with the composition of the slag, and its effect upon the distribution of the sulphur between molten iron and slag, as introductory to a series of contributions to the theory of the metallurgical processes. The method of measurement, viscosity, apparatus, furnace and other accessories mentioned in this paper have been described fully in a Bureau of Mines report.1 THE LITERATURE ON SLAG VISCOSITY The viscosity of blast-furnace slag had not been measured previous to the investigation described in this report. A number of investigators have determined the "fusibility," or softening temperature, of slags by means of the cone method or, other deformation method, but these methods supply only limited information regarding the temperature-viscosity relations.-of the slag in question. Any deformation method that may be employed indicates only the temperature at which the slag attains a more or less definite viscosity, the magnitude of the value obtained depending on the method used. For details of the various methods used by different investigators, see, the Bureau of Mines paper already referred to. An isolated measurement by Doelter on a single mixture at 1,300° C. represents the highest temperature reached in the various viscosity investigations previous to those described in this report, in which results have been referred to absolute units. Arbitrary deformation tests have of course been made at much higher temperatures.

Jan 2, 1917

By E. N. Doyle

Since the mid-1930's a number of plants, using the principles of heavy media separation, have been installed throughout the world. In cases involving lead, zinc or lead-zinc ores the reasons for the choice of this type of beneficiation process have fallen into four major categories: A) The economic recovery of additional distinctly separate products, such as dolomite limestone at the Mascot Plant (1) of the American Zinc Co., and the ferrosilicon produced by St. Joseph Lead Company. (2) B) The elimination of a large portion of run-of-the-mine ore prior to grinding and flotation, to allow increased throughput with low capital cost. Examples of this approach are the Levante and Ponente plants of the Montevecchio Company in Italy (3) and the frequent choice of the Sink-Float process by the Penarroya Company of Paris. C) The processing of a sedimentary deposit, in which the valuable mineral is contained in the matrix separating the boulders, as was the case at the St. Joseph Lead Company plant at Haydon Creek (4) and also at Bunker Hill Mining and Smelting, Kellogg, Idaho. D) The simplification of Around support programs in mines by allowing greater freedom of action in the extractive pattern. An example of this choice is Cominco’s Sullivan plant which came into being as part of an extensive proposal to update the mining, crushing, transportation, grinding and beneficiation processes. (5)

Jan 1, 1970

By Frederick Apgar

(Butte Meeting, August, 1913.) THE valuable results that have followed the application in recent years of microscopic methods of research to problems of ore genesis have been significant, but possibly the recognition of their practical importance is not as general as might be, and while, as a scientific method of investigating ores and rocks, the advantage derived through the use of the microscope is unquestioned, its utility as an aid in solving shining problems arising during actual every-day mine examination and operation may not be fully appreciated. Perhaps the roost logical method of showing some of these practical applications of the microscope will be to consider first the prospect stage of a mining venture, then the uses to which the instrument may be put during the operation of a working and developed mine, and, finally, to discuss some of the problems of a metallurgical nature that ii-my arise during milling and smelting the ore. The valuation of mining property as a preliminary to acquiring ownership or determining the advisability of investing time and money in an enterprise is one of the most important and delicate problems that come before the mining engineer. The many and variable factors that have to be taken into account, as, for example, the geology of the district, availability of supplies, probable mining costs, transportation facilities, and the quality of ore, require a careful balancing of costs against recoverable values.

Jan 6, 1913

By R. Van A. Norris

Although mechanical appliances for the ventilation of mines have been known siuce very early times (one being mentioned in Agricola's De Re Metnllica, 1657), it is only within the last forty years that such appliances have been generally used. A great number of different ventilators have been invented and used, but the varions forms of centrifugal machines having proved their efficiency, have now almost conlpletely replaced all others. Most if not all of the machines in use in this country are of this class, being either open-periphery fans, or closed, with chimney and spiral casing, of a more or less modified Guibal type. The theory of such machines has been demonstrated by Mr. Daniel Murgue in Theories and Practice of Centrifugal Ventilating Machines, translated by A. L. Steavenson. His statement may be condensed thus : Let a = orifice in a thin plate, of such area that its resistance to the passage of a given quantity of air equals the resist ance of the mine. I o = orifice in a thin plate of such area that its resistance to the passage of' a given quantity of air equals that of the machine. Q = quantity of air passing in cubic feet per minute. V = velocity of air passing through a. Vo = velocity of air passing through o. h = head iu feet air-column to produce velocity IT h, = head in feet air-column to produce velocity V,.

Jan 1, 1892

By Arthur Knapp

The practical application of mud-laden fluids in wells has been the subject of many papers.' However, there seems to have been little investigation of what actually happens when mud-laden fluids are applied to a loose porous sand. The assumption is that the fluids penetrate the sands and that there is some plastering action. The degree of penetration and the relation of plastering action to wall stability is not generally known. This paper describes a series of experiments made in an attempt to observe, in laboratory apparatus, the action of mud-laden fluids under conditions simulating those to be found in a well. For the purposes of this discussion all fluids containing solid matter in suspension are mud-laden fluids. Series I: Penetration of the Pores of Uncemented Sands The subject of the penetration of porous formations by water is discussed in detail in Water-Supply Paper No. 67 of the U. S. Geological Survey. No attempt was made to repeat the experiments described therein. The results of the first experiment of this series are given simply to show the capacity of the apparatus used. The conditions in this first experiment were maintained throughout the remainder of this and the second series, except where noted. The experiments of Mills, McCoy, and others on subsurface flows, adjustments, migrations, etc., deal with the oil, water or gas within the porous beds.V he experiments described herein deal with the conditions immediately surrounding the bore hole.

Jan 1, 1923

By Arthur Taggart

SOME years ago, A. M. Gaudin and one of the authors published a paper showing removal of tar acids from solution by sulfides preferentially as compared to gangues (specifically by galena as compared to quartz).1 The underlying phenomenon was classed as adsorption, and the paper went on to develop the general thesis that so far as water-soluble frothing and collecting agents in flotation are concerned, the phenomenon of adsorption is one of controlling importance. Adsorption was defined in that paper as "a process of rearrangement of a system, which results in establishing a difference in concentration, as between the interfacial layers and the bulk of the phases, of a substance or substances initially uniformly dispersed in one or several of the phases." The paper went on to develop the relation between adsorption and surface energy according to Gibbs' equation (which may be thrown into the form U/c = KdT/dc, where U = excess concentration in surface layer, c = concentration, T = surface tension, and K is a constant), and pointed out that, according to this equation, degree of adsorption and change in surface tension vary directly. The present paper offers a somewhat different definition for the term adsorption; and sets up, in sweeping terms, the generalization that simple chemical reaction underlies the functioning of the flotation reagents which control mineral collection, when these reagents are soluble in and act from solution in the water of the pulp.

Jan 1, 1930

By Richard H. Rein, John Chipman

Liquid slags of the system SiO2-Ca0-MgO-A1~03 were equilibrated with liquid Fe-Si-C alloys in graphite or Sic crucibles at 1600°C in pure CO gas at atmospheric pressure, and the silicon content of both phases determined. Ternary slugs of the systern SiO2-CaO-A12O3 were also studied at 1550°C. The silicon content of the metal phase saturated with both graphite and SIC is 22.0pct at 1550°C and In the iron blast furnace, as in nearly all carbon-reduction processes, some silicon is transferred from slag to metal. The importance of this reaction is enhanced by its indirect effect on the transfer of sulfur from metal to slag, and this has stimulated a comprehensive research program on the equilibrium distribution of silicon between slag and metal. Earlier studies'-3 of this same problem provided data for calculation of the thermodynamic activities4 of the components in SiO,-CaO-A1,O3 slags. 22.4 pct at 1600°C. The temperature at which the phases cristobalite, gvaphite, $ SiC, liquid slag, Fe-Si-C alloy, and CO gas at 1 atm pressure can coexist in equilibrium was found to be 1533°C. The results agree well with earlier studies. They are shown graphically as lines of constant silicon cmtent in the metal which also are lines of constant SiO, activity in the slag.

Jan 1, 1963

By Edward Estabrook

THE Salt Creek oil field in Natrona County, Wyo., is the largest pool that has been found in the Rocky Mountain region and one of the largest in the United States. Many features of its production records are of peculiar interest, because of the unusual slowness with which it has been developed. This paper is published by the permission of the Midwest Refining Co., whose records have been freely drawn upon. Many mem¬bers of the Midwest organization have assisted in the collection of the material, but Messrs. F. E. Wood and L. E. Smith have been particularly helpful. The Salt Creek oil field is situated on a great dome with a closure of about 1500 ft., which rises at the northern end of a long anticline extending north-northwest by south-southeast for fully 25 miles. The productive area includes parts of townships 39 and 40 north and ranges 78 and 79 west of the sixth principal meridian. The Teapot oil field occupies a minor dome at about the center of the same anticline and adjoins the Salt Creek oil field on the southeast. The Teapot Naval Reserve includes the Teapot Dome and about 760 acres of the Salt Creek dome. In this paper, the Salt Creek oil field will be considered as' including all of the dome, except that part which lies within the Teapot Naval Reserve and the area west of the dome where oil is produced from shale crevices.

Jan 9, 1925

By Frederic Becket

IN a recent article,1 which described the softening effect of columbium in plain high-chromium steels, the authors stated that their investi-gations had shown columbium to be also a particularly valuable inhibitor of intergranular corrosion in steels of the 18 per cent chromium, 8 per cent nickel type. It is the purpose of the present paper to record some of the results obtained through the introduction of columbium to the austenitic chromium-nickel steels. The damaging effects of this type of corrosion have become so widely known as to restrict considerably the applications of the steels under consideration, and therefore there is little question of the importance of the goal to be attained. Numerous contributions concerning the susceptibility of the aus-tenitic chromium-nickel steels to intergranular corrosion have appeared during the past few years, and among others who have dealt construc-tively with the subject are such well-known authors as Strauss and Houdremont of Germany, Hatfield of England, and Bain in the United States. Different theories have been propounded as to the cause of intergranular corrosion, and various remedial measures have been proposed, the majority of which involve the use of addition agents. Titanium is the addition agent at present most generally employed, as suggested by Houdremont and modified as described by Bain, Aborn and Rutherford.2 Little has been published on the effects of holding these steels for long periods at the relatively lower temperatures in the presence of

Jan 1, 1934

By Douglas R. Piteau, Dennis C. Martin

Instability of rock slopes may occur by failure along pre- existing structural discontinuities, by failure through intact material or by failure along a surface formed partly along discontinuities and partly through intact material. Although certain fundamental failure modes are recognized, the mechanisms of slope failure are varied and complex. Such mechanisms are governed by the engineering geology conditions of the rock mass, which are almost always unique to a particular site. An understanding of failure mechanisms requires a knowledge of the physical, mechanical and strength properties of the intact material and discontinuities which make up the rock mass, as well as the structural geology and hydrogeology. These engineering geology parameters also must be evaluated with respect to the slope geometry to determine failures which are kinematically possible. Only after obtaining a reasonable appreciation of the possible failure modes can a rational mechanical stability analysis be carried out. Both two-dimensional and three-dimensional failure mechanisms should be considered in assessing the design of rock slopes. Simple analyses methods are used initially to identify those possible failures which could control slope stability. More complex and detailed analyses usually are required for a few critical failure modes which could control stability, or where a more complex type of failure mechanism is envisaged. Complex failure mechanisms are usually identified when assessing previous slope failures. More detailed information concerning slope geometry and engineering geology parameters must be acquired where analyses must be more rigorous.

Jan 1, 1983

By Augustus Locke

In 1900, when. the public first heard of "secondary enrichment," the Butte chalcocite seemed clearly supergene. Mining, through successive regions of leached capping, bonanza sulfide, and sulfide less rich, had paused at lean bottom levels which, though chalcocite-bearing, suggested the waning of copper. The deepest chalcocite, at 1500 ft., was yet too shallow to disturb the supergene hypothesis. But, with deeper mining, lean levels yielded to fat ones. Here and there they showed, within the same vein, an inverted distribution, chalcopyrite above and chalcocite below. To the miners' astonishment, they carried chal-cocite, unaffected by cross faults, on an independent course to the depth of 2500 ft. The pattern of ore distribution, hitherto revealed only in fragments, was now appearing in perspective, and, in the depth of the chalcocite, was beginning to make Butte differ from all districts where the chalcocite is indubitably supergene. The idea of hypogene origin at length came into favor; by 1913, when Sales' advocated this origin, the argument had become a powerful one. This argument rested on field evidence; but, already, there was beginning to emerge microscopic evidence not included in this argument. Especially pertinent was the proof that (1) the deep chalcocite lies in-mixed with bornite, often microscopic; (2) the deep chalcocite often replaces bornite; and (3) replacement of bornite by chalcocite is accomplished more easily than that of pyrite, enargite, or chalcopyrite. The microscopic evidence has been accumulating for ten years and it demands

Jan 1, 1924

By D. B. Gillies

IN 1938 the Republic Steel Corp. announced that it had leased the ore mines and other property of the Witherbee Sherman Corp. at Port Henry, N. Y. The announcement brought forth an interesting reaction. Two questions were asked repeatedly: (1) Is the iron product high grade? (2) Is there a substantial reserve? The answer to both questions was and is a decided and emphatic "Yes."

Jan 1, 1943