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By J. Campbell

The hydrostatic tensions in pure metals and long freezing range alloys are evaluated theoretically considering the viscous flow of residual liquid and the general plastic collapse of the casting. The former mechanism operates until the radii of the remaining liquid channels are of the order of 10-3 cm radius, after which the second process limits the attainable negative pressures which range from —1500 to -4200 atm for nickel, aluminum, copper, and iron. In previous reports1'2 the maximum possible hydrostatic tensions developed during solidification have been evaluated employing spherical symmetry. This inevitably involves the concept of totally confined liquid regions, the reality of which has recently been brought into serious doubt3 following observations of the freezing of various transparent materials. Regions of interdendritic liquid which are apparently about to be isolated by the growth of dendrite arms are observed not to be cut off because the advance of the dendrite tips is arrested until the region has completely solidified. Although this may be the result of the very low melting point liquid available at this late stage in freezing, or the result of a higher rate of heat transfer to the dendrite tips because of the acceleration in liquid flow rate near the completion of solidification, this point need not concern us. In this paper an attempt is made to approximate more closely to real conditions; thus the assumption of confined liquid regions is abandoned and cylindrical symmetry adopted. It has also been necessary, therefore, to consider the viscous flow of residual liquid through the remaining channels in the pasty zone. Furthermore, the rather special conditions of spherically symmetric solidification led to extremely high solidification rates and hence unusually high tensile stresses as solidification neared completion; the cylindrical Symmetry appears to yield solidification rates and stresses which are more typical of real castings. The rate of solidification is first considered since this critically affects both the flow of the liquid and the creep of the solid.

Jan 1, 1969

By Wilbur T. Stuart

TO assist the mining industry in attacking problems of water control, the U. S. Geological Survey has begun a program of research in mining hydrology. In certain fundamental respects water control is similar to development of water supplies from wells or to the drainage of agricultural lands, as many of the tools developed in recent years for quantitative ground-water problems are applicable, with modification, to mine-water problems. In 1952 a 30-day pumping test conducted jointly by the Eureka Corp. Ltd. and the Defense Minerals Exploration Agency provided an opportunity to gain knowledge concerning water movements around a flooded mine shaft. The methods of analyzing the data may be used as a guide for the evaluation of similar problems elsewhere. The Fad shaft of the Eureka Corp. is on Ruby Hill, 1 1/2 miles west of Eureka, Nev. The shaft was completed at a depth of 2465 ft in November 1947 at a site adjacent to the downfaulted block in which the ore was found. As the drift on the 2250 level progressed toward the ore zone, a large flow of water was encountered after the Martin fault was intersected. This flow exceeded the installed pump capacity, and an unsuccessful attempt to recover the shaft and the 2250 level was made in 1948.1, 2 Geology and Hydrology: The complex structure of Ruby Hill is that of an anticline broken first by thrust faulting and later by normal faults. The present orebody comprises several mineralized zones within a block of the Eldorado limestone of middle Cambrian age which was downfaulted 1400 to 1600 ft, and it may be related to a similar body mined at a higher level south of the Ruby Hill fault. At the depth of the largest zone of ore the block is roughly rectangular in shape, about 1000 ft wide and 1500 ft long, and dips about 30" NE, see Fig. 1. It is apparently bounded on the south by the Ruby Hill fault, on the east by the Jackson fault, on the north by the Martin fault, and the west by the Bowman fault. Within the block, but between the Ruby Hill and the Martin faults, are the Office and Adams Hills faults; west of the block and the Bowman fault are the Albion and Spring Valley faults. There are many conflicting reports concerning the water-yielding characteristics of the Eldorado limestone and the condition of the fault zones, that is, whether they are open or tight. However, the diamond-drill records indicate that open spaces as much as 2 or 3 ft across were encountered, and considerable cementing and lining of holes was necessary to maintain circulation of drilling fluid. There is also evidence that the Eldorado limestone was cavernous where it was mined in the early days south of the Ruby Hill fault. At the site of the Fad shaft the formations encountered from the surface down included the Pogonip limestone, Dunderberg shale, Hamburg limestone, and Secret Canyon shale. These formations did not yield large quantities of water to the shaft. The Pogonip limestone, which appears to be permeable and might yield water elsewhere, is above the water table in the vicinity of the shaft. The Secret Canyon shale, immediately overlying the Eldorado in some places but in most places separated from it by the Geddes limestone,3 is apparently tight and does not transmit water. During the 30-day test period the shale briefly confined the water in the underlying formations so that artesian conditions were observed in drillholes E and F, which are cased into the Eldorado limestone, whereas unconfined conditions were observed in drillholes B, C, and D, which were open to the shale. The Geddes limestone, which normally lies between the Secret Canyon shale and the Eldorado limestone, was not encountered in the Fad shaft. The Geddes, a flaggy, fractured limestone, is reported capable of yielding large volumes of water. Water stored in the interstices of this thin-bedded limestone within the Ruby Hill fault zone on the 1200 level of the Locan shaft drowned the pumps in 1923 when the Richmond-Eureka Mining Co. attempted to explore the area along the fault. Eldorado limestone was not encountered in the Fad shaft. In the ore-block area the Eldorado limestone was not entirely offset from other water-yielding formations by movement along the Bowman fault; therefore it may be hydraulically connected with the other formations. Adjacent to the Ruby Hill, Jackson, and Martin faults, the Eldorado lies in contact with other possible water-yielding formations. One of these, the Prospect Mountain quartzite, is separated from the Eldorado by thin, sheared, and broken beds of the Geddes within the Ruby Hill fault zone. A limited examination by the author of the Prospect Mountain quartzite in the Richmond mine at a higher level and south of the Ruby Hill fault indicates that the quartzite is poorly permeable. The monzonite mass south of the quartzite would be a further barrier to the flow of water. The poor permeability of this area is substantiated by records of levels at which water was encountered south of the Ruby Hill fault. In view of the normally low rate of ground-water recharge, if this desert area had been permeable, water levels could not have been maintained at altitudes of many hundred feet above the present water table west and north of Ruby Hill. Thus the ore-bearing block of Eldorado limestone is in contact with possible water-yielding rocks on at least two sides, and if the fault zones are possible conduits for water circulation the geologic and hydrologic conditions are suitable for the infinite-aquifer type of analysis as used and modified here. History of Pumping: During sinking of the Fad shaft a maximum pumping rate of 1500 gpm kept the shaft dewatered sufficiently, but in March 1948, after the 2250 level drift passed through the Martin fault into the Eldorado limestone, the pumps and shaft were flooded. Subsequently additional pump-

Jan 1, 1956

By J. A. Singmaster

A REPORT that it did not pay to use present-day galvanized iron on account of the short life of the material, accompanied by proofs of the state-ment in the form of a tabulated history of the first costs of various kinds of building materials and their main-tenance expense, started an investigation of modern galvanized products. At the very outset it was apparent that our experience with galvanized products was by no means unique. Correspondence with the State Agricultural Depart-ments, the Agricultural Experiment Stations, the County Agents and State Granges all over the United States brought a mass of complaint on this same score. Visits to large buyers of galvanized sheet and wire revealed the same condition coupled with an ever-increasing use of substitutes for galvanized iron. We believe, therefore, that the title of this article is fully warranted by the experience of the consuming public. A study of the proceedings of the various societies having to do with the testing and use of sheet iron and steel products revealed a tremendous amount of work on the life of the base metal itself. Great stress was laid on differences in life of various types of iron and steel, the difference amounting at best to months rather than years. Very little recent attention has been paid to a study of the life of the zinc coating and the causes of its present-day lack of durability. There have been some real exposure studies published, how-ever, which show that the weight of the zinc coating determines the protection afforded by the galvanizing, which is of far greater influence on the life than the base-metal composition. An interesting paper was published by the Phillipine Journal of Science in 1916, entitled: "Galvanized Roofing in the Phillipines," a contribution from the Bureau of Science of the Phillipine Island Government. The author, Mr. Arguelles, found on 18 old galvanized sheets, after from 30 to 35 years' exposure, from 2.3 to 4.1 oz. of zinc per sq. ft. of sheet and sums up the study by saying: Of the various factors influencing the durability of galvanized iron which have been studied with a view towards accounting for the difference in behavior of old and modern sheet, it appears evident that the greater weight of zinc per unit of area on the former accounts for the greater durability.

Jan 10, 1922

By Graham Bright

Before the arrival of central-station power, all coal and metal mines generated their own power and, in many cases, these isolated power plants gave a fair continuity of service. In coal mines that produce considerable gas, it is essential that power be available at all times for operating the ventilating fan and the hoist, if the mine is of the shaft type. In the case of an isolated power plant, if trouble should develop with the fan the men can be hoisted quickly when the mine is of the shaft type. On the other hand, if trouble develops with the hoist, the fan can be kept in operation, and there will be no necessity of haste in getting the men from the mine. Now that central-station power is being used so extensively for mine service, the continuity of service with gaseous mines is very important. : Inherently, the central station is much more reliable than any isolated plant, but trouble may occur on the transmission lines which may prevent the transmission of power for a considerable time. : Some mines have kept their steam equipment intact and ready for operation in case the purchased power should fail. This is expensive procedure, for the boiler plant must be fired at all times so that the emergency power will be quickly available. In a number of instances, gasoline-engine driven generators have been installed to furnish emergency power for the service hoist. As most service hoists are of the alternating-current type, the generator of the gasoline-engine driven set is usually of the a.c. type and is arranged to drive the service hoist motor at full speed, or an extra motor that can be thrown into gear on either the main or service hoist and the hoist operated at a greatly reduced speed. This arrangement is used because it is difficult and expensive to obtain and install large gasoline-engine driven units. The author has recently developed a plan by which the main hoist and the fan can both be operated at reduced speeds, in case of loss of power from a central-station power system. In this plan a gasoline-engine

Jan 1, 1923

By Persifor Frazer

I DESIRE to say that, owing to the number of papers which have been more or less crowded at this session of the Institute, and the fact that, as one of the Local Committee, I have the distinguished honor to feel somewhat like one of the hosts, I should not tax the patience of members at this late hour, but would have my paper read by title were it in any way possible to do this. But the task I have set myself this evening is to present to the eyes of the members of the Institute certain objects which have occupied more or less of my time during the last eighteen months or two years. The objects I allude to are some of the igneous rocks of this country, which, until quite recently, have been less understood than any others. It will be well known to some of the members that some of the cooled lavas of a previous age of our planet, when not directly coarsely crystalline and granular, were considered and spoken of as " natural glasses," or perfectly uncrystalline, vitreous, or hyaline masses of matter. Among the first results of the use of the microscope was the dispersion of this fallacy. Sir David Brewster, Mr. H. C. Sorby, and William Nichol (the discoverer of the celebrated calcite prism, which bears his name), had, with greater or less success, examined sections of various rocks and minerals, both by transmitted and reflected light, and also in the form of powder. But, until the genius of Vogelsang undertook the subject, these investigations had no permanent value, nor did they constitute an independent line of mineralogical and geological research. Since the close of his labors, by Vogelsang's premature and much-lamented death, the subject has been made one of renewed interest by his brother-in-law, Ferdinand Zirkel, as well as by Rosenbusch, Tschermak, and many others abroad, and at home by the commencement of a systematic study of the traps of Connecticut by Messrs. E. D. Dana and G. W. Hawes, of New Haven, and by the splendid set of described sections of the traps of the West which have been furnished by Zirkel to illustrate Clarence King's report. I had the honor of presenting a large number of thin sections of our traps at the Washington meeting, for the inspection of the members, with the aid of a table microscope belonging to the Smithsonian Institution. Here I propose to project these sections upon the

By Graham Bright

Before the arrival of central-station power, all coal and metal mines generated their own power and, in many cases, these isolated power plants gave a fair continuity of service. In coal mines that produce considerable gas, it is essential that power be available at all times for operating the ventilating fan and the hoist, if the mine is of the shaft type. In the case of an isolated power plant, if trouble should develop with the fan the men can be hoisted quickly when the mine is of the shaft type. On the other hand, if trouble develops with the hoist, the fan can be kept in operation, and there will be no necessity of haste in getting the men from the mine. Now that central-station power is being used so extensively for mine service, the continuity of service with gaseous mines is very important. : Inherently, the central station is much more reliable than any isolated plant, but trouble may occur on the transmission lines which may prevent the transmission of power for a considerable time. : Some mines have kept their steam equipment intact and ready for operation in case the purchased power should fail. This is expensive procedure, for the boiler plant must be fired at all times so that the emergency power will be quickly available. In a number of instances, gasoline-engine driven generators have been installed to furnish emergency power for the service hoist. As most service hoists are of the alternating-current type, the generator of the gasoline-engine driven set is usually of the a.c. type and is arranged to drive the service hoist motor at full speed, or an extra motor that can be thrown into gear on either the main or service hoist and the hoist operated at a greatly reduced speed. This arrangement is used because it is difficult and expensive to obtain and install large gasoline-engine driven units. The author has recently developed a plan by which the main hoist and the fan can both be operated at reduced speeds, in case of loss of power from a central-station power system. In this plan a gasoline-engine

Jan 1, 1923

By A. P. Anderson, J. H. Jensen, W. E. Breckoff

Bromine is the intermediate member of the halogen family of elements between iodine, a solid, and chlorine, a gas. The name is derived from the Greek "bromos," meaning stench. Bromine is the only nonmetallic element that is liquid at room temperatures with a melting point of -7.2° C and a boiling point of 58.78º C. Reddish brown in color, it dissolves easily in water to yield a red solution. Bromine volatilizes at ordinary temperatures to a red vapor that is very irritating to the eyes, nose, and throat. Density of the liquid is 3.12 and gas weighs 7.59 gpl at standard conditions. As the element is highly active, it exists in nature only as bromide compounds. Bromine was discovered by Antoine Jerome Balard in seawater bitterns in 1826 and first prepared in quantity in 1860. Distribution Bromine is widely distributed in nature and compounds occur in solution in natural brines, in seawater, saline lakes, oil and gas well brines, and in evaporite chloride minerals. The concentration of bromine salts ranges from 60-65 ppm in seawater to several thousand ppm in oil well brines and saline lakes. The distribution of bromine in marine evaporite minerals and in the solutions from which they crystallized was determined many years ago by H. E. Boeke (1908). Theoretical aspects regarding the geochemistry of bromine have been published in numerous papers (Raup and Mite, 1969). Bromine occurs in solid solution in carnallite and sylvite associated in potash deposits; in halite in salt beds; salt in oil shales; and in trona deposits. Its presence is useful as a guide in geochemical exploration. The analysis of small amounts of bromides in the presence of large amounts of chlorides is discussed by W. Schwerdtner (1963). Manganese, iron, and iodine may interfere with the determination. Other analytical methods are discussed at length in the literature (Stenger and Atchison, 1964). Sources and Reserves The sources and reserves of bromine, given in Table 1, appear ample to meet present and foreseeable requirements in all producing countries. With the occurrence of bromine salts in seawater and other brines, the potential for bromine production is worldwide. It has been estimated that 99% of all commercially recoverable bromine is in the ocean. However, actual subterranean brines having a higher bromine content than seawater will continue to be the preferred sources of bromine for the foreseeable future. [ ]

Jan 1, 1983

By A. H. Geisler, J. H. Keeler

Preferred orientations in unalloyed zirconium were determined by the Geiger-counter spectrometer X-ray diffraction technique. With increasing P-annealing temperature the following textures were obtained: l—a retained a-annealing texture, 2—additional orientations predictable from the a-p (Burgers) relationship, and 3—a texture derived from a cube texture in the p phase. Earlier work on cold-worked and a-annealed zirconium was reappraised to show a quantitative dependence of rotations on temperature and to identify spurious areas of some of the pole figures. IN a previous paper,' the preferred orientations of high purity zirconium sheet were described for cold-rolled and annealed samples. Annealing temperatures up to 900°C, which is slightly above the allotropic transformation temperature, were explored. Of interest was the observation that the orientation of the hexagonal-close-packed material after annealing in the temperature range of the stable body-centered-cubic phase was similar to that of the material which had been annealed in the a temperature region, although a change in texture would be expected because of the many new orientations based on an orientation relationship between the two forms of zirconium. The reversion to an original orientation after an allotropic transformation cycle is not unusual. It has been found for titanium,"* for thallium," and for cobaltB among the hexagonal metals. Burgers found in his original work7 that, when zirconium was cooled through the allotropic transformation and then reheated, the body-centered-cubic phase reverted to the original orientation. Additional experimental work has been carried out to further explore the textures of zirconium after annealing in the temperature range above the allotropic transformation. In addition, a reappraisal was made of the earlier results for zirconium' in light of recent work on titanium4 which has shown that the texture type depends quantitatively on the temperature of annealing and that spurious areas may be encountered in the pole figures of hexagonal metals determined by the X-ray spectrogoniometer technique of analysis. Experimental Procedure Crystal-bar zirconium prepared by the iodide process was the material used in this investigation. The major impurity was hafnium which was less than 0.3 pct. The composition obtained by spectro-graphic analysis is given in Table I. Cold-rolled specimens were prepared from crystal bar by a series of reductions of approximately 0.010 in. until the sheet reached a thickness of 0.010 in., after which it was cold rolled to 0.001 in. thickness between sheets of alloy steel. The total cold reduction amounted to about 99.8 pct. Specimens were annealed for % hr at 1000" to 1100" to 1200°C or 1 hr at 1400°C in an evacuated Vycor or quartz tube. The transmission pole figures were obtained by

Jan 1, 1956

By Sidney Powers

CONTENTS PAGE Distribution of fields 4 History of development 6 Origin of oil 7 Structure, accumulation and migration 8 Reservoir rocks 9 Methods of drilling and exploration 10 Oil-field statistics : 12 Description by regions: United States: Appalachian region ; 12 East-central states 17 Kansas 18 Oklahoma : 19 Texas : 24 Arkansas : 32 Louisiana 33 Mississippi ....... 34 Rocky Mountain region : 34 California 37 Canada 41 Mexico 43 Cuba 46 Bibliography 46 THE purpose of this brief account- of the occurrence of petroleum in North America is to make available to those who have a knowledge of geology, but who are not engaged in the petroleum industry, a few salient facts about the location of oil and gas fields, their productivity, the important structural types of accumulation and the age of the rocks containing petroleum. A few useful data and statistics are furnished, yet not complete statistics that are available elsewhere. Geology has been treated in simple terms because the reader is presumed to have little interest in the names of formations and of oil sands. Mineral deposits are more or less analogous. Whether oil or metals, minerals are found in rocks, largely in sedimentary rocks which carry water or have at one time carried it. A genetic or accumula-

Jan 1, 1931

By Russell W. Dayton

The metallurgical polarization microscope has been utilized in several researches in the last few years, thus attaining a fair degree of prominence, but little has been written in a manner suitable to a metallurgist concerning the theory of this instrument. In this investigation the theory was carefully studied, and the results are presented here in a detailed manner, yet as simply as possible. The theory is discussed with particular reference to the three chief functions of the instrument: (1) determination of anisotropy; (2) effect of strain; and (3) identification of inclusions. Each of these is investigated experimentally, with especial attention to the mechanism of producing any effect. Where possible, the discussion is supplemented by photomicrographs. The instrument used had numerous defects as a polarization microscope; these and their remedies are discussed. In the microscopic study of transparent mineral sections (chalcography) the use of polarized light has aided tremendously in the identification of a mineral. The determination of strain in transparent substances (photoelasticity) by the use of polarized light has lately become a commercial process, used in testing finished glass articles. The success of the use of polarized light with opaque materials has not been so great. The magnitude of the effects obtained is much less than that of the corresponding effects with transparent materials, and the mechanical difficulties are much greater. Königsberger,"' i in 1909, was the first to apply polarized light to the microscopic study of opaque substances; Endell and Hanemann(2) were the next, in 1913. In 1919 and 1920, Wright(3,4) prepared two papers on the subject. In the first he developed the detailed mathematical theory from the viewpoint of the electromagnetic theory of light, and in the second described the various methods in use, giving improvements of his own. Schwarz(5)

Jan 1, 1935

By Russell W. Dayton

The metallurgical polarization microscope has been utilized in several researches in the last few years, thus attaining a fair degree of prominence, but little has been written in a manner suitable to a metallurgist concerning the theory of this instrument. In this investigation the theory was carefully studied, and the results are presented here in a detailed manner, yet as simply as possible. The theory is discussed with particular reference to the three chief functions of the instrument: (1) determination of anisotropy; (2) effect of strain; and (3) identification of inclusions. Each of these is investigated experimentally, with especial attention to the mechanism of producing any effect. Where possible, the discussion is supplemented by photomicrographs. The instrument used had numerous defects as a polarization microscope; these and their remedies are discussed. In the microscopic study of transparent mineral sections (chalcography) the use of polarized light has aided tremendously in the identification of a mineral. The determination of strain in transparent substances (photoelasticity) by the use of polarized light has lately become a commercial process, used in testing finished glass articles. The success of the use of polarized light with opaque materials has not been so great. The magnitude of the effects obtained is much less than that of the corresponding effects with transparent materials, and the mechanical difficulties are much greater. Königsberger,"' i in 1909, was the first to apply polarized light to the microscopic study of opaque substances; Endell and Hanemann(2) were the next, in 1913. In 1919 and 1920, Wright(3,4) prepared two papers on the subject. In the first he developed the detailed mathematical theory from the viewpoint of the electromagnetic theory of light, and in the second described the various methods in use, giving improvements of his own. Schwarz(5)

Jan 1, 1935

By B. S. Norris, Charles R. Austin

The stresses which initiate deformation processes in metals are fundamentally important in the study of the mechanical properties of metals. A point of inflection in the load-elongation curves obtained for single crystals' has been rather too readily interpreted as a true yield point, and the critical resolved shearing stress on the plane of slip taken as a material constant. Even early work showed that the stress at this point varies with rate of loading, but it has not been generally appreciated that creep tests under static loads alone are suited for determining the existence or nonexistence of a yield point.* It has now been shown by Miller that single crystals of zinc3 when loaded statically begin to yield at loads too small to measure; as a result there is no case now known, apart from that cited in the present paper, in which a true critical stress for yielding has been demonstrated for single crystals of metals. The case of iron has especial interest: the existence of an upper and lower yield point and of an elongation at the yield point in ordinary iron and steel marks this substance as unusual, though the effects have been found to a very minor degree in other metals and alloys. $ Most alloys do not show such marked phenomena when appreciable yielding begins, and accordingly modern practice is to speak of the yield strength of such materials, a stress read from the load-elongation curve after elongation has begun, rather than yield point. The special behavior of iron suggests that it is more likely that single crystals of iron should have a true yield point than other metals. The study of the mechanical properties of metals and alloys requires a determination of the crystallographic mechanism of deformation, wlletller deformation proceeds by slip, twinning, or cleavage, or a combination of these, and a determination of the stresses that induce these modes of deformation. With this information, a study of the rates of work-

Jan 1, 1938

By B. S. Norris, Charles R. Austin

The stresses which initiate deformation processes in metals are fundamentally important in the study of the mechanical properties of metals. A point of inflection in the load-elongation curves obtained for single crystals' has been rather too readily interpreted as a true yield point, and the critical resolved shearing stress on the plane of slip taken as a material constant. Even early work showed that the stress at this point varies with rate of loading, but it has not been generally appreciated that creep tests under static loads alone are suited for determining the existence or nonexistence of a yield point.* It has now been shown by Miller that single crystals of zinc3 when loaded statically begin to yield at loads too small to measure; as a result there is no case now known, apart from that cited in the present paper, in which a true critical stress for yielding has been demonstrated for single crystals of metals. The case of iron has especial interest: the existence of an upper and lower yield point and of an elongation at the yield point in ordinary iron and steel marks this substance as unusual, though the effects have been found to a very minor degree in other metals and alloys. $ Most alloys do not show such marked phenomena when appreciable yielding begins, and accordingly modern practice is to speak of the yield strength of such materials, a stress read from the load-elongation curve after elongation has begun, rather than yield point. The special behavior of iron suggests that it is more likely that single crystals of iron should have a true yield point than other metals. The study of the mechanical properties of metals and alloys requires a determination of the crystallographic mechanism of deformation, wlletller deformation proceeds by slip, twinning, or cleavage, or a combination of these, and a determination of the stresses that induce these modes of deformation. With this information, a study of the rates of work-

Jan 1, 1938

CONTENTS PAGE HESSE, A. W,-Safeguarding Coal-mining Operations against Danger from Oil and Gas Wells. Discussed by A. W. Hesse, T. G. Fear, George H. Ashley, George S. Rice, W. E. Fohl, R. V. Norris, S. A. Taylor, F. B. Tough, C. W. Gibbs, A. Hurlburt, S. W. Meals 1 DAWSON, THOS. W.-Belt Conveying of Coal at H. C. Frick Coke Company Mines. Discussed by F. F. Jorgensen, Thos. W. Dawson, Graham Bright, A. W. Hesse 13 OTTO, HENRY H.-Ultimate Recovery from Anthracite Coal Beds. Discussed by R. V. Norris, S. A. Taylor, Henry H. Otto, Douglas Bunting, Graham Bright, Howard N. Eavenson, J. B. Warriner 15 HOSLER, Rush N.-Schedule Rating Coal Mines in Pennsylvania for Compensation Insurance Rates. Discussed by E. A. Holbrook, W. W. Adams 17 ARCHBALD, HUGH.-Application of Gaussian Curve to Mining Industry. Discussed by Donald A. Laird, T. T. Read 19 ASH, SIMON H.-System of Coal Mining in Western Washington. Discussed by Eli T. Conner, Simon H. Ash 21 MILLER, J. S.-Method of Mining a Steeply Pitching Anthracite Vein by Successive Skips. Discussed by Eli T. Conner, J. S. Miller, J. B. Warriner 22 HARRINGTON, GEORGE B.-New Orient, an Unusual Coal Mine. Discussed" by George S. Rice, Eli T. Conner, John A. Garcia, George B. Harrington, F. F. Jorgensen, Graham Bright, W. M. Hoen, George N. Simpson, W. C. Adams, R. W. McNeill, Chas. C. Whaley, Carl Scholz, E. T. Gott, Andrews Allen 23 PERROTT, G. ST. J.-Properties of Liquid-oxygen Explosives. Discussed by George S. Rice 48 Safeguarding Coal-mining Operations against Danger from Oil and Gas Wells Discussion of the paper of A. W. HESSE, presented at the New York Meeting, Feb-ruary, 1925, and issued, as Paper No. 1412-F, with MINING AND METALLURGY, February, 1925. A. W. HESSE.-The well under investigation, No. 101, Fig. 2, was started about Sept. 5, 1921, and drilled-in in November. The first hole was started with a 13-in. bit and reached the Pittsburgh coal at a depth of 563 ft.; at 602 ft. the 10-in. casing was run in and the well was continued with a 10-in. bit and 1400 ft. of 8-in. casing was put in. It was then continued to a depth of 1770 ft. and 6-in. casing put in; then continued to a depth of 2555 ft. where the gas was struck. As the well produced only about 100,000 cu. ft. per day. 2-in. tubing was used to conduct the

Jan 6, 1925

By Charles S. Barrett

This paper is a progress report covering metallographic applications of the electron microscope that have been made during the past year at Carnegie Institute of Technology. An account is presented of the techniques that have been most satisfactory, the difficulties encountered, the resolution obtained, and the peculiarities that have been noted in the microstruc-tures. About 1200 exposures have been made during the year on the instrument, which is an RCA type B2 transmission microscope,' and a number of these have been selected to illustrate the results obtained. prints are also included showing the common types of falsities—to borrow a term from the biological field, the "artifacts." ln brief, the paper is a record of our attempt to determine the value of the electron microscope in the study of the structure of metals and alloys. In addition to comments on techniques and the quality of photomicrographs obtainable with them, the paper discusses the nature of the etch attack on a few metals, and the possible relation between the fine structure revealed by etching and the mosaic block structure of the grains, since numerous papers and reviews are available on the subject of imperfection in crystals, the comments here may be very brief; in fact, are restricted almost entirely to points having to do with recent theories relating the strength of metals to imperfections and to spacings of slip lines. Specimen Preparation and Photographs Mechanical polishing by hand was used throughout this work. Precautions that must be taken in microscopy at high magnification, which have been well explained by Vilella in his book on Metallographic Technique for Steel, are likewise important with the electron microscope. This applies particularly to the need for these polishing and etching (each successive polish becoming less severe and each etch lighter), since the fina1 etch should in general be no heavier than is used for oil-immersion optical microscopy and in many instances should be much lighter (compare Figs. 6a and 7a, 6d and 7b). An extremely light etch, of course, is incapable of cutting through a flowed layer of appreciable thickness. Unquestionably it would be very advantageous in each instance to compare the structures obtained by electrolytic polishing with those obtained by mechanical polishing, but difficulties with the electrolytic method have prevented this in the following collection of prints. The choice of etchant is important, of course; for example, picral proved superior to nital for tempered martensite. With the exception of Figs. Ib and 16, the replicas used were of silica, deposited upon polystyrene and floated from the polystyrene in ethyl bromide according to the method of Heidenreich and Peck.2 The samples were mounted in Bakelite, polished and etched, then the polished Bakelite

Jan 1, 1944

By Charles S. Barrett

This paper is a progress report covering metallographic applications of the electron microscope that have been made during the past year at Carnegie Institute of Technology. An account is presented of the techniques that have been most satisfactory, the difficulties encountered, the resolution obtained, and the peculiarities that have been noted in the microstruc-tures. About 1200 exposures have been made during the year on the instrument, which is an RCA type B2 transmission microscope,' and a number of these have been selected to illustrate the results obtained. prints are also included showing the common types of falsities—to borrow a term from the biological field, the "artifacts." ln brief, the paper is a record of our attempt to determine the value of the electron microscope in the study of the structure of metals and alloys. In addition to comments on techniques and the quality of photomicrographs obtainable with them, the paper discusses the nature of the etch attack on a few metals, and the possible relation between the fine structure revealed by etching and the mosaic block structure of the grains, since numerous papers and reviews are available on the subject of imperfection in crystals, the comments here may be very brief; in fact, are restricted almost entirely to points having to do with recent theories relating the strength of metals to imperfections and to spacings of slip lines. Specimen Preparation and Photographs Mechanical polishing by hand was used throughout this work. Precautions that must be taken in microscopy at high magnification, which have been well explained by Vilella in his book on Metallographic Technique for Steel, are likewise important with the electron microscope. This applies particularly to the need for these polishing and etching (each successive polish becoming less severe and each etch lighter), since the fina1 etch should in general be no heavier than is used for oil-immersion optical microscopy and in many instances should be much lighter (compare Figs. 6a and 7a, 6d and 7b). An extremely light etch, of course, is incapable of cutting through a flowed layer of appreciable thickness. Unquestionably it would be very advantageous in each instance to compare the structures obtained by electrolytic polishing with those obtained by mechanical polishing, but difficulties with the electrolytic method have prevented this in the following collection of prints. The choice of etchant is important, of course; for example, picral proved superior to nital for tempered martensite. With the exception of Figs. Ib and 16, the replicas used were of silica, deposited upon polystyrene and floated from the polystyrene in ethyl bromide according to the method of Heidenreich and Peck.2 The samples were mounted in Bakelite, polished and etched, then the polished Bakelite

Jan 1, 1944

By R. Ebeling, M. F. Ashby

The paper is in two parts. The first develops the formulae and method needed to calculate the size, nu)nber, spacing, and volume fraction of hard or inert particles in the interior of a specimen from measurernents made on an extraction replica; throughout, the spread of- particle sizes in a single specimen is taken into account, and the extraction efficiency of the replica is considered. A method for testing whether the particles are randotnly distributed in space is described, and the spacing of randomly distributed particles is discussed. The second Part describes the application of the method to copper containing spherical particles of silica; the description includes an estimate of the errors involved, and a comparison of this with alternative methods. All parameters except uolume fraction can be determined satisfactorily, and the method offers advantages over other electron-,rzicroscopic techniques when dealing with hard particles in a softer matrix, or inert particles in a chem-ically less inert matrix. 1 HE experimental measurement of sizes and numbers of discrete particles of a second phase embedded in a matrix material from opaque, plane sections has been considered by many authors, notably by Fullman.' It is assumed that, when the specimen is sectioned, the particles are also sectioned, so that the diameters of the circles of intersection of particles with the plane of the cross section ("surface diameters") are measured. It is difficult to derive the distribution of true particle diameters ("volume diameters") from measurements of the distribution of "surface diameters" on a plane section. The measurement of size and numbers of small second-phase particles by transmission electron microscopy through thin foils of matrix containing the particles has been described by Cahn and ~uttin~' and by ~illiard.~ Because of overlap and the fact that particles which intersect the foil surface may be sectioned whereas those in the bulk of the foil are not, it is again difficult to measure the true distribution of particle sizes. The use of replicas for this sort of measurement has not been analyzed in detail. A replica made from an opaque cross section, thus replicating the circles of intersection of particles with the plane of section, is analyzed by Fullman's method and suffers from the same difficulties. Under certain circumstances, however, extraction replicas can be used, and offer a special advantage in that they make the determination of the true distribution of particle diameters particularly simple. It is the purpose of this paper to describe this extraction replica method. Consider the example of an alloy consisting of SiOz particles, whose mean diameter is about 1000A, dispersed in a copper matrix. When the alloy is sectioned and mechanically polished, the particles are not sectioned, because they are much harder than the matrix, and so will be either left in the surface or pulled out whole, and because the particle size is smaller than the abrasive size of even the finest abrasive. The particles are chemically inert in solutions which chemically etch or electropolish the matrix, so that chemical treatments do not section the particles either. (Experimental measurements of particle shape in this alloy confirm this—truncated particles are never seen.) Small, hard or inert, particles are therefore not sectioned when the specimen is sectioned and polished. An extraction replica taken from this polished surface shows the true "volume" diameter of each extracted particle; the distribution of diameters seen on the replica is the surface distribution of true "volume" diameters, and the volume distribution of true "volume" diameters is easily derived from it. The extraction replica method is not subject to the difficulties associated with sectioning of particles, and avoids the problem of overlap from which the transmission method suffers. The method is well-suited for studying hard particles in a soft matrix. Examples are provided by internally oxidized alloys, oxide-dispersion strengthened metals like T.D. Nickel, and carbides, nitrides, and strong intermetallic compounds in metals. It should be possible to adapt polishing techniques in alloys containing softer but inert particles to avoid sectioning the particles (say by electropolishing or etching). The method is tested and illustrated in Sections 8 and 9 by applying it to a dispersion of spherical SiO2 particles in a copper matrix. I) SYMBOLS Symbols are defined where they first appear in the text. Volume fractions of particles are denoted by the symbol f, particle diameters by x, center-to-center particle spacings by D, and numbers of particles by N. Mean particle diameters and standard deviations about these means are denoted by x and a. Both arithmetic (subscript A) and geometric (subscript G) means are employed. In this paper we measure the distribution of true diameters of particles which touch or pass through a random-plane section of the specimen. We may want to know the distribution of particle diameters in the

Jan 1, 1967

By E. P. Polushkin, Henry L. Shuldener

THIS paper describes the results of microscopic examination of a series of brass pipes removed from apartment and office buildings in New York City, adjacent localities on Long Island, and Philadelphia. They were selected as typical of approximately four hundred pipe specimens obtained over a period of five years during an investigation of corrosion in hot-water installations. A part of the investigation is reported in this paper and includes a brief history of the pipes, a description of their inside surface and microstructure, and a study of the effects of corrosion, with particular reference to the structural aspects of local and selective dezincification. Although the bibliography on the corrosion of brass pipes is quite extensive, it refers almost entirely to corrosion in sea water. The authors believe that their examination of this series of pipes, which had been subjected to the corrosive action of fresh water for various lengths of time, may throw some additional light on the problem of corrosion. PIPES EXAMINED The pipes were made by different manufacturers and their sizes range from ¾ in. to 4 in. nominal inside diameter, the majority being within I to 2 in. They can be divided into two groups according to chemical composition: (I) with a copper content of 60 to 62 per cent and (2) with a copper content of 65 to 68 per cent. The first group (pipes made of Muntz metal) comprises 22 pipes and the second (pipes made of high brass) comprises 18 pipes. The pipes had been in service in various locations in the hot-water systems of the buildings involved. Some were taken from horizontal lines in the basement, some from overhead distributors and some from vertical risers. The distance, in terms of feet of pipe, of the specimens from the hot-water generator was no less than 75 ft. and often 100 to 300 ft. In the majority of cases the water-heating equipment was provided with a regulator to limit the temperature of the hot water supply. The normal range of temperature in pipe systems of this kind is 100° to 160°F. WATER SUPPLIES The average chemical composition of the water supplies carried by the pipes is shown in Table I. In evaluating the corrosiveness of a natural water, four factors are considered of prime importance: namely, hardness, alkalinity, pH and silica content. The waters listed in Table I are characterized by relatively low hardness, low alkalinity, low pH and low silica content. The waters of lower pH and higher CO2 content are more corrosive. A characteristic of all of these waters is that they do not deposit a protective mineral coating as do waters with high bicarbonate of lime content, which would be reflected

Jan 1, 1944

By D. J. Weintritt, R. G. Hughes

Statistics show arz increase in the average depth of wells drilled in recent years. As a corollary to this trend, drilling fluids have been improved in an effort to meet the problems inherent at temperatures approaching 500°F. Of importance are (1) deterioration of mud components and (2) the effect of solids on filtration and rheological properties. High-temperature, stable water-base and oil-bare muds are discussed. Those areas in which differences exist are pointed out. Results are based on data taken from the Fann consistotneter, rheometer and shear-strength measurements, static and dynamic filtration tests, methy-lene blue test for bentonite solids and specific heat measLrrenlents of muds. INTRODUCTION Higher well temperatures go along with the fact that the average depth of wells continues to increase. Recent data by Gardner' lists 137 completions deeper than 15,000 ft for the first half of 1964 with a record second-half total of 167 wells drilling or proposed. In addition, there has been an increase in drilling for steam for power production or mineral recovery. In this application the depths are modest, but the mud may approach the critical pressure and temperature of water. Scearce and Magnon' report drilling mud used at temperatures of about 700°F in the Salton Sea area of California. Most deep wells have been drilled with water-base muds. In recent years, however, there has been a substantial increase in the use of oil-base muds because of technological advances in effective additives. The significance of this development was dealt with in considerable detail by Simpson and his co-workers.3 Additiona1 field data have now been obtained to indicate that oil muds are competitive in control, performance and cost with the best types of water muds for use at high temperaturc. This parallel offer of two very different fluid systems, each offering a similar variability in performance, cost and convenience, has created the need to evaluate the merits of these fluids under specified conditions so that the advantages and disadvantages of each can be weighed in relation to the over-all drilling program. This paper is not intended as a review of all the factors. Rather, it attempts to emphasize: (1) important condltions and facts peculiar to high-temperature drilling muds, (2) that more than one imposed test condition or testing method is necessary to describe the quality of a mud at high temperature and (3) that elaborate experimental precautions are necessary whenever laboratory data are used in selection of a mud for field use. WHAT IS A HIGH-TEMPERATURE DRILLING FLUID? For the purpose of this discussion, a high-temperature drilling fluid is any system so formulated or treated to economically minimize the effects of temperature on the properties of the fluid. Our experience in drilling fluids suggests that these effects become obvious for many mud materials at temperatures of 300F or higher. It is understood that hydrolysis of starches, depoly-merization of certain organic thinners, or irreversible chemical reactions (such as that of clay and lime) can affect filtration, viscosity and shear strength at less than 300F. However, the temperature level is not a serious point and in no way affects the precautions and techniques used in this study. An up-to-date review of the literature on high-temperature drilling fluids and the many variations was treated by Rogers'in 1963. EXPERIMENTAL REQUIREMENTS TESTING EQUIPMENT AND PROCEDURES With the advent of deeper drilling and increased demand for temperature-stable drilling fluids, new testing equipment and laboratory techniques were devised for the evaluation of drilling fluids subjected to elevated temperature and pressure. While the equipment has not been standardized, it is in widespread use. Milligan et al. Qescribe a filtration cell for determining the filtration properties of drilling fluids at temperatures in excess of 300F. They showed the effect of variations in temperature and pressure on oil and water muds filtered in the 300 to 400F range. The dynamic filtration apparatus described by Simpson6 permits the study of the filtration properties to temperatures of 350F for drilling fluids circulated over sandstone cores. Watkins et al.' describe the use of pressure bombs for studying the effect of prolonged periods of elevated temperature upon the gelation or solidification of drilling fluids. Chisholm et a1.' describe the use of a modified cement consistometer adapted for use in drilling fluid evaluations. A similar consistometer is used in this study, although the application and data-recording method have been changed. The consistency of a mud sample is measured by timing the movement of a soft iron bob which is magnetically moved up and down in the sample container.* Changer in the time of travel and the temperature of the mud at that moment are plotted with a two-point Brown Elec-tronik Recorder. A 10-in. chart with a speed of 4-in./hr is used. Fia.- 1 is a generalized internretation of the data ob-

Jan 1, 1966

THE CHAIRMAN (G. H. CLEVENGER, Stanford University, Cal.).¬I would like to ask Mr. Pyne if he has had any experience inn the use of chromite as refractory under conditions that are highly reducing? I am reminded of an experience I once had with an electric furnace. I imagined that chromite would form a splendid lining, but it soon disappeared; hence it seems probable that, under highly reducing conditions at a high temperature, chromite is a very poor refractory. F. R. PYNE.-In copper smelting the atmosphere is generally neutral, or slightly oxidizing; we do not use highly reducing atmospheres at all, not even in the matting furnace. You can take the chromite brick and treat it as you would an iron ore, obtaining ferro-chrome very readily, from which the copper will separate. We have done this; in fact, at one time we considered installing a small electric furnace for the production of ferro-chrome. FOREST RUTHERFORD, New York, N. Y.-During the time I was general superintendent at the smelter of the Copper Queen Consolidated Mining Co., at Douglas, Ariz., a great many experiments were made on the furnaces and settlers with different kinds of brick, and I agree with Mr. Pyne's statements about chrome brick. Their power to absorb metals is very great, and as they cannot be smelted at any temperatures obtainable in a copper furnace, to get rid of the bats and extract the metal from them is quite a problem. We finally got down to using chrome brick only for lining the settlers, out of which we often got a life of upwards of 2 years, and for lining the blast-furnace bottoms, for the reason that chrome brick can be heated and wet, or wet after being heated, without going to pieces, whereas under these conditions magnesite brick will break down very rapidly. We also used a layer of chrome brick above and below an 18-in. band of magnesite brick put on the slag line of the reverberatories, in order to separate the magnesite from the silica brick, fearing that they would slag each other and let the wall drop. The idea worked, but became unnecessary on account of a change made in the method of feeding the furnaces. Chronic brick will not stand up under pressure so well as a good Grecian or Austrian magnesite brick, on account of the poorer bonding properties of the materials from which the chrome brick is made.

Jan 4, 1918