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By Russell Franks

IN recent years a considerable tonnage of the 18 per cent chromium and 8 per cent nickel steels has been used in lightweight high-strength structures that must be resistant to deterioration under atmospheric conditions. These steels are austenitic in character and their strength can best be increased by cold-working. Although a marked increase in tensile strength is obtained, claims have been made that the cold-worked steels do not possess fully satisfactory elastic properties. Under certain conditions, however, this has caused no great concern, because, as explained by Ragsdale,1,2 the cold-rolled steels have been widely applied for construction of lightweight, high-strength trains using spot welding for joining purposes. Ffield3 agrees that the ease with which thin sections of the cold-rolled 18-8 steels can be joined by spot welding is greatly in their favor, but that they would be more satisfactory if higher elastic properties and a higher modulus of elasticity could be obtained. He states that, as far as the mechanical properties are concerned, the straight chromium stainless steel is superior to the cold-worked 18-8 steel, and in order to illustrate, he presented the data of Fig. 1, which also give a stress-strain curve for a low-carbon 13 per cent Cr steel. Ffield? pro-posed that columbium-bearing or titanium-bearing cold-rolled 18-8 steels be given a heat-treatment (preferably for 1 hr.) in the range 400° to 600°C. to precipitate carbides in order to obtain better mechani-cal properties. Discussions by Sutton,4,5 de Ganahl,6,7 8 Krivobok and Lincoln,9 Knerr,10 and Thaden11 have given further information on the properties of the cold-rolled 18-8 steels compared with other materials used in light-weight, high-strength structures. These investigators and others point out that the ultimate tensile strength of the cold-rolled 18-8 steel can be increased to 200,000 lb, per sq. in. or higher; Krivobok et al. indicate that

Jan 1, 1940

George IV. Goetz, Milwaukee, Wis.: Mr. Campbell deserves much credit for his interesting paper. The literature of the development of the open-hearth process is distributed in many technical journals, and is difficult of access to many engineers. Since the development of the basic process, the open-hearth furnace has been raised from a subsidiary to an independent position. Certain high grades of soft steel can be produced in the basic open-hearth furnace, which cannot be produced by any other known process. In the United States the charges for the acid process generally consist of either scrap and pig-iron or so-called wash-metal and scrap : the pig-and-ore process, as carried out in England, is practiced but very little. The introduction of the basic process has made it possible to use about four times as much pig-iron with scrap as can be used in the acid mixtures. The availability of a cheap pig-iron, very low in silicon and sulphur, and carrying several per cent. of manganese, is one of the reasons why the basic open-hearth process has developed so rapidly in Germany, as regards the output per furnace and the excellent quality of the material produced. The acid Bessemer steel has an inherent stiffness, which is plainly shown when spring steel is made by the Bessemer and by the openhearth processes. In order to get them of about equal stiffness, the open-hearth steel must have about 0.60 per cent. carbon ; whereas, the Bessemer steel must then have ahout 0.45 carbon, the remaining constituents being apparently about the same in each product. It has proved impracticable, with American coke-pig-iron, to interrupt blowing at a certain point in order to make hard steel; and experience has therefore shown that it is best to eliminate nearly all the carbon, and then to recarburize to the desired point. This practice

Jan 1, 1894

C. H. MATHEWSON, New Haven, Conn. (written discussion *).-In a recent discussion of Dr. Jeffries' paper on tungsten,1 J. C. W. Humfrey,2 after taking exception to certain of the author's ideas relative to the cohesion of A and C metal, expresses the opinion that future research is likely to develop a method of preparing tungsten possessing "mechanical properties in line with those of other metals." The present paper by Dr. Jeffries begins with a determination of comparative properties of tungsten, copper, and iron, in which much dissimilarity is apparent, and ends with a coherent explanation as to why much of this dissimilarity is natural and inevitable, thereby supplying theoretical means for visualizing the changing properties of metals in general, once certain fundamental facts are known. The author's reasoning is primarily from the standpoint of the amorphous theory and his principal achievement is the development of an idea f differential cohesion according to conditions of temperature, etc., between A and C metal (which was first plainly suggested by Rosehain and Ewen, in their papers on Intercrystalline Cohesion of Metals) along with associated ideas, so as to give us a really useful working theory. I have come rather reluctantly to believe in the amorphous theory, or some theory admitting a modification of the ordinary crystalline phase so as to permit differential properties within the conglomerate, mainly because in no other way does it seem possible to account for observed changes of properties with temperature, etc. The very best illustration f the competency f the amorphous theory in this respect is seen in this and other recent papers by the author. All fractures through normal or healthy metal that have been preceded by deformation are supposed, by Dr. Jeffries, to take place either through the amorphous phase or at certain boundaries between amorphous and crystalline material; his reference to fractures, both members of which are similar in appearance and do not reveal a preexisting coarse-grained structure because of a coating of amorphous metal, indicates his preference for the former interpretation.

Jan 5, 1919

By W. Irwin Moyer

Two methods for the rapid valuation of oil properties are in common use. The one best known and most widely used is the "per barrel" value, based on the present daily production of the well, without regard to its past performance or the history of the sand or pool from which it produces. The second method is the "time to pay out," or the lengt of time required for a well to place itself upon the credit side of the ledger, from which time the returns from its production (less the operating expenses) will be clear profit. The time basis for valuation is also commonly used in the appraisal of an undeveloped lease. In most oil fields, it is not thought good business to invest in production that will not pay out in at least 4 to 5 years. Nearly all buyers (except in certain regions of very persistent production like the deep-sand territory of the Appalachian field) expect wells to pay out in considerably less time than this. Like the barrel-per-day price, the time necessary for a well to pay out has been determined for each field, so that one frequently hears a field or district referred to as having a certain time to pay out. This is considered the norm for that field or district and the buyer and seller base their value, to greater or less extent, on their belief in the accuracy of this time. The writer long ago became convinced of the inaccuracy of the barrel-per-day method, except when greatly modified for local conditions, such as the age of the wells, their economic limit, operating conditions in the field, the future price of oil, and the persistence of the sand as a producer. When so modified, this method becomes more of an analytic or predicted probable-yield valuation. While the appraiser may not go through each step in a valuation based on future returnable revenue, his knowledge of the field and the local conditions surrounding his leases make it possible for him to estimate a fair sales value that, in many cases, will be a close approximation to the truth. This is quite different from she commonly understood barrel-per-day value, in that the conditions turrounding the sale of one lease or property at a fair market value may

Jan 1, 1923

By W. Irwin Moyer

Two methods for the rapid valuation of oil properties are in common use. The one best known and most widely used is the "per barrel" value, based on the present daily production of the well, without regard to its past performance or the history of the sand or pool from which it produces. The second method is the "time to pay out," or the lengt of time required for a well to place itself upon the credit side of the ledger, from which time the returns from its production (less the operating expenses) will be clear profit. The time basis for valuation is also commonly used in the appraisal of an undeveloped lease. In most oil fields, it is not thought good business to invest in production that will not pay out in at least 4 to 5 years. Nearly all buyers (except in certain regions of very persistent production like the deep-sand territory of the Appalachian field) expect wells to pay out in considerably less time than this. Like the barrel-per-day price, the time necessary for a well to pay out has been determined for each field, so that one frequently hears a field or district referred to as having a certain time to pay out. This is considered the norm for that field or district and the buyer and seller base their value, to greater or less extent, on their belief in the accuracy of this time. The writer long ago became convinced of the inaccuracy of the barrel-per-day method, except when greatly modified for local conditions, such as the age of the wells, their economic limit, operating conditions in the field, the future price of oil, and the persistence of the sand as a producer. When so modified, this method becomes more of an analytic or predicted probable-yield valuation. While the appraiser may not go through each step in a valuation based on future returnable revenue, his knowledge of the field and the local conditions surrounding his leases make it possible for him to estimate a fair sales value that, in many cases, will be a close approximation to the truth. This is quite different from she commonly understood barrel-per-day value, in that the conditions turrounding the sale of one lease or property at a fair market value may

Jan 1, 1923

By Raymond J. Kujawa

For general purposes, insulating materials may be any of those mineral substances that provide a barrier between a desired human environmental feature and an unwanted condition. In this sense, radiation shields, electrical insulations, cryogenic insulation, and acoustical barriers would qualify. For this chapter only the thermal and acoustic insulations used for the median range of normal comfort control will be covered. Because of their magnitude and complexity the other fields are left to other chapters. In another sense, this section deals only with the ultra-lightweight aggregates and insulations, rather than the multitude of light-weight structural materials. Definitions and Uses The insulating materials covered in this chapter are the three groups of mineral products that provide thermal or acoustic barriers through the median temperatures encountered in home and industry. The three mineral categories are perlite, vermiculite, and the silicate wools whether they be categorized as glass, mineral, or rock. Perlites are those amorphous aluminum silicates with minor impurities that take the form of a felsitic, glassy lava possessing a pearl-like luster and concentric cracking. In a more commercial sense the term is used to describe either the natural or processed acidic, volcanic glass, containing from 2 to 5% combined water, that may be converted to a frothy mass by heating rapidly to the softening point. Vermiculites are micaceous, hydrated magnesium iron aluminum sheet silicates of varying composition. Commercial vermiculites are any of these sheet silicates that are capable of sufficient expansion on rapid heating to make an acceptable, highly porous product. Mineral wools, rock wools, silicate cottons, glass fiber are generic names for manufactured fibers in which the fiber forming substance may be slag, certain rocks, or glass. The fibers may be made by a blowing or spinning process. The resultant fibers may be felted or matted or gathered in the manner best suited to the use. The three groups may be used competitively to insulate ceilings and walls. The fibers have strong advantages in this area as they may be manufactured in batts that are stable in residential wall construction. The perlites and vermiculites are more suited to insulate cores and cavities of masonry walls and as plaster and concrete aggregates for thermal insulations. Vermiculite is widely used for insulating attic floors. Because of manufacturing techniques and controls, the glass fibers have made great strides as composites in the plastics industry but only a few of these uses classify in the insulation category.

Jan 1, 1975

By W. Irwin Moyer

Two methods for the rapid valuation of oil properties are in common use. The one best known and most widely used is the "per barrel" value, based on the present daily production of the well, without regard to its past performance or the history of the sand or pool from which it produces. The second method is the "time to pay out," or the length of time required for a well to place itself upon the credit side of the ledger, from which time the returns from its production (less the operating expenses) will be clear profit. The time basis for valuation is also commonly used in the appraisal of an undeveloped lease. In most oil fields, it is not thought good business to invest in production that will not pay out in at least 4 to 5 years. Nearly all buyers (except in certain regions of very persistent production like the deep-sand territory of the Appalachian field) expect wells to pay out in considerably less time than this. Like the barrel per day price, the time necessary for a well to pay out has been determined for each field, so that one frequently hears a field or district referred to as having a certain time to pay out. This is considered the norm for that field or district and the buyer and seller base their value, to greater or less extent, on their belief in the accuracy of this time. The writer long ago became convinced of the inaccuracy of the barrel per day method, except when greatly modified for local conditions, such as the age of the wells, their economic limit, operating conditions in the field, the future price of oil, and the persistence of the sand as a producer. When so modified, this method becomes more of an analytic or predicted probable yield valuation. While the appraiser may not go through each step in a valuation based on future returnable revenue, his knowledge of the field and the local conditions surrounding his leases make it possible for him to estimate a fair sales value that, in many cases, will be a close approximation to the truth. This is quite different from the commonly understood barrel per day value, in that the conditions surrounding the sale of one lease or property at a fair market value may

Jan 1, 1922

By H. R. Barnhurst

IT would be a difficult matter to trace from the beginning the very few improvements made in the burning of fuels prior to 1860. Doubtless the crossing of the sticks of wood in building a, wood fire early appealed to our savage ancestry as a means of expediting its effectiveness for their crude culinary purposes. Stones and andirons came later in assisting the admission of air to the under part of the fuel bed, while beacons and cressets utilized metal bars as supports for the same purpose. It is probable that Tubal Cain owed his success to the use of bellows making possible the use of mixed fuel and charge upon a hearth. With the development of working in east iron, grate bars cane in, and they are still with us doing duty in every household and almost every art where heat is a factor. Little was done beyond these crude methods prior to 1860. With the advancement of knowledge came the fuel-gas producer, a. natural child of the retorts employed in supplying illuminating gas. It is only within the last 15 years that the conclusion became general that complicated systems for saving heat would not remedy deficiencies in its primary development, and within that tine there has been great advancement in the means of producing initially fire of high efficiency, so that to clay we are moving rapidly toward loth high development and high absorption, with the resultant of high efficiencies. In studying the subject of the availability of pulverized coal as a fuel, it may occur to ask, why has this not come up earlier? This question would be naturally prompted by recalling the fact that Thomas Crompton's English patents upon his methods were issued to Min nearly 40 years ago. A conclusive answer to this, however, is that Crompton at that time had very crude facilities for raking what was at best a, very imperfect pulverization of the coal, and the expense of preparation was very great. He does not seem to have been aware of the advantage of a thorough drying of the coal in the

Jan 10, 1913

By Charles B. Dudley

While working, during the summer of 1877, upon the "Chemical composition and Physical Properties of Steel Rails," the results of which are given in my report with this title, I was struck with the surprising wear which some of the rails, which would ordinarily be called soft rails, had endured. At that time I knew of no chemical measure of softness except low carbon, and I found that a numher of rails with low carbon had endured as high or higher tonnage, with apparently as little loss of metal by wear, as those with higher carbon. My own work on steel rails that summer did not embrace any definite experiments as to the amount of metal worn off the rail per million tons which had passed aver it; and so I could get no more definite answer from that work, to the question at the head of this paper, than was given by comparing the appearance of the worn section of the rail with its tonnage. This comparison, however, served to arouse in my mind the query, whether the commonly received opinion as to the relation between the hardness and wearing power of steel is correct, as applied to steel rails. This opinion, if I am right, is: the harder the steel, the better will be the wear, and the limit of hardness is simply one of safety; hard, brittle steel being, of course, more liable to break than soft, tough steel. The query, although aroused, did not bear any immediate fruit, and, as will be evident to any one reading it, the report above referred to was written with the commonly received opinion in mind. Since that time I hare collected a little information upon this subject, which I should be glad to submit to the Institute, if for no other purpose, for the sake of arousing attention, and directing study to the question of hardness versus wear in steel rails. Before making known this information, howevcr, permit me a few words in reference to hardness. How shall we measure the hardness of steel ? Of the various ways of getting indications as to the hardness of steel, which are known, three mill serve our present purpose. These are: 1st. High carbon. It is generally agreed, I think, that at least within proper limits, the greater the amount of combined carbon in a piece of steel, the harder the steel, and I need not do

Jan 1, 1879

By Chas. B. Dudley

WHILE working, during the summer of 1877, upon the "Chemical Composition and Physical Properties of Steel Rails," the results of which are given in my report with this title, I was struck with the surprising wear which some of the rails, which would ordinarily be called soft rails, had endured. At that time I knew of no chemical measure of softness except low carbon, and I found that a number of rails with low carbon had endured as high or higher tonnage, with apparently as little loss of metal by wear, as those with higher carbon. My own work on steel rails that summer did not embrace any definite experiments as to the amount of metal worn off the rail per million tons which had passed over it; and so I could get no more definite answer from that work, to the question at the head of this paper, than was given by comparing the appearance of the worn section of the rail with its tonnage. This comparison, however, served to arouse in my mind the query, whether the commonly received opinion as to the relation between the hardness and wearing power of steel is correct, as applied to steel rails. This opinion, if I am right, is: the harder the steel, the better will be the wear, and the limit of hardness is simply one of safety ; hard, brittle steel being, of course, more liable to break than soft, tough steel. The query, although aroused, did not bear any immediate fruit, and, as will be evident to any one reading it, the report above referred to was written with the commonly received opinion in mind. Since that time I have collected a little information upon this subject, which I should be glad to submit to the Institute, if for no other purpose, for the sake of arousing attention, and directing study to the question of hardness versus wear in steel rails. Before making known this information, however, permit me a few words in reference to hardness. How shall we measure the hardness of steel ? Of the various ways of getting indications as to the hardness of steel, which are known, three will serve our present purpose. These are: 1st. High carbon. It is generally agreed, I think, that at least within proper limits, the greater the amount of combined carbon in a piece of steel, the harder the steel, and I need not do

Jan 1, 1879

By M. F. Trice

Pyrophyllite is a hydrous aluminum silicate (A1²Si4O10(OH)²)1 that, occurs in both the foliated and the massive forms. The foliated variety resembles talc in that it has a greasy feel, a pearly luster, perfect basal cleavage, and usually is white, although in some deposits apple green, gray, brown, russet, and nearly black specimens may be found. The massive deposits of pyrophyllite yield pearl gray to light tan aggregates, some of which are so friable that they may be crushed with the hands into a fine gritty powder. Frequently specimens of the massive variety are studded with crystals of radial structure. The mineral has a specific gravity of about 2.7 and a hardness of 1 on Mohs' scale.' The chemical composition of commercial pyrophyllite reflects the mineralogy of the deposits, which, according to Stuckey12 contain pyrophyllite and quartz, together with chloritoid, sericite, and a few other minerals of negligible importance. The latter, he says, ('are noticed in but small quantities to the extent they might occur as accessory constituents of an igneous rock or as products of regional metamorphism or weathering. . . . Quartz is abundant everywhere except in the very best grades of pyrophyllite." Analyses of specimens from several deposits are listed in Table 1, showing that the silica content varies from 57 to 73 per cent and the alumina from 22 to 33 per cent. Oxides of iron and the alkaline metals are collectively present, with one exception, to an extent of about 1 to 1.5 per cent. Sources At present, North Carolina is the only commercial source of pyrophyllite, although the mineral has been found in small quantities in many parts of the world. The North Carolina deposits are in the "Carolina Slate Belt," which traverses the center of the state in a southwesterly direction. This belt varies from 8 to 50 miles in width. Two major deposits of pyrophyllite lie along its eastern boundary, in what is known as the Deep

Jan 1, 1942

By M. F. Trice

Pyrophyllite is a hydrous aluminum silicate (A1²Si4O10(OH)²)1 that, occurs in both the foliated and the massive forms. The foliated variety resembles talc in that it has a greasy feel, a pearly luster, perfect basal cleavage, and usually is white, although in some deposits apple green, gray, brown, russet, and nearly black specimens may be found. The massive deposits of pyrophyllite yield pearl gray to light tan aggregates, some of which are so friable that they may be crushed with the hands into a fine gritty powder. Frequently specimens of the massive variety are studded with crystals of radial structure. The mineral has a specific gravity of about 2.7 and a hardness of 1 on Mohs' scale.' The chemical composition of commercial pyrophyllite reflects the mineralogy of the deposits, which, according to Stuckey12 contain pyrophyllite and quartz, together with chloritoid, sericite, and a few other minerals of negligible importance. The latter, he says, ('are noticed in but small quantities to the extent they might occur as accessory constituents of an igneous rock or as products of regional metamorphism or weathering. . . . Quartz is abundant everywhere except in the very best grades of pyrophyllite." Analyses of specimens from several deposits are listed in Table 1, showing that the silica content varies from 57 to 73 per cent and the alumina from 22 to 33 per cent. Oxides of iron and the alkaline metals are collectively present, with one exception, to an extent of about 1 to 1.5 per cent. Sources At present, North Carolina is the only commercial source of pyrophyllite, although the mineral has been found in small quantities in many parts of the world. The North Carolina deposits are in the "Carolina Slate Belt," which traverses the center of the state in a southwesterly direction. This belt varies from 8 to 50 miles in width. Two major deposits of pyrophyllite lie along its eastern boundary, in what is known as the Deep

Jan 1, 1942

By C. H. Li, R. J. Stokes, T. S. Liu

Poly crystalline silver chloride specimens having different micro structures were prepared by extruding monocrystals or precompressed powder at varying temperatures. Extrusion at high temperature (370°C) produced a Fully recrystallized equi-axed material which was brittle and fractured by simple cleavage below its transition temperature (60°C for notched specimens). Extrusion at low temperatures (down to -196°C) produced an extremely tough cold-worked material with grains elongated in the extrusion direction. This material fractured below its transition temperature (which varied from —20" to —200°C) by an intergranular mode. It is concluded that cold work increases the resistance to transgranular cleavage. Fracture is then de-flected to propagate intergranularly ouer surfaces making an angle with the tensile axis with a corresponding improvement in notch toughness. This deflection is greater for extruded powder than for extruded monocrystals because of the extremely elongated grain shape. PREVIOUS work1,' on the fracture properties of fully recrystallized silver chloride under notch impact conditions has indicated that the fracture behavior is rather invariant. Thus polycrystalline materials originating from a number of sources ranging from relatively pure Harshaw single crystals to commercial-purity powder and prepared by hot extrusion at 370°C all fracture by simple cleavage with a ductile-brittle transition at 60°C, see Fig. 1. This behavior is also typical for fully annealed single crystals and appears to be fundamental to silver chloride for the particular loading conditions and notch configuration adopted. One way in which this characteristic fracture behavior can be modified is by the dispersion of alumina particles in the silver chloride matrix.' Then, particularly when the alumina particles are in the shape of spheres, the duc tile-brittle transition is much less sharply defined and occurs over a range of temperature, the transition temperature is lowered considerably and the fracture mode changes from simple cleavage to a fibrous or shear mode. The reason for this change is believed to be partly due to the nucleation of cavities in the region of the dispersed alumina particles which influences the state of stress locally and the distribution of plastic constraint at the root of the notch. It is emphasized however that this is not the sole factor responsible for the increase in toughness. In extruded materials it is reasonable to expect that the resultant grain size, texture, and the residual cold work will be influenced by the presence of a dispersed phase. The present experiments were initially designed to determine the extent to which cold work influenced the fundamental ductile-brittle transition temperature and fracture mode of silver chloride. They were stimulated by the discovery that silver chloride could be extruded at temperatures as low as -25°C when commercial-purity powder was used and as low as -196°C when single crystals were used. This working temperature was far below that previously used (370°C) and it was found that such extruded material was exceedingly tough. The reasons for the enhanced toughness and its relation to the previous work on silver chloride-alumina compacts will be discussed. EXPERIMENTAL PROCEDURE Materials Used. Two forms of silver chloride were used in this study: i) silver chloride powder

Jan 1, 1964

By Cecil Desch

THIS annual lecture, under the auspices of the Institute of Metals Division, and which was illus- trated by lantern slides, has been printed in full and a limited number are available for distribution on request. Some excerpts from the lecture are given below: Ever since the simple geometrical relations of crystals were discovered, it has been recognized that their proper-ties are best explained by assuming that their ultimate particles are arranged on a space lattice, and that the char-acteristics of that lattice determine the shape of the crystal and its physical and mechanical properties. Modern ex-amination by means of X-rays has widened that concep-tion and given it greater; definiteness, and the atoms are now regarded as the particles forming the space lattice. The splendid achievements of investigators in this field have made it possible to state, for a large number of sub-stances, the form and dimensions of the lattice. The char-acteristic of a lattice is that a unit of simple geometrical form is repeated at regular intervals in three dimensions so as to fill the entire crystal. It follows that there must be certain planes in which the atoms are more closely packed than in planes drawn at any angle to them, and it is these planes of closest packing which play the greatest part in determining the growth and other properties of the crystal. There are actually two stages in crystallization, what-ever be the medium in which it occurs. The first is the ap-pearance of crystal nuclei; the second the growth of those nuclei to form crystals of appreciable .size. The first is clearly a kinetic phenomenon. In the molten mass, solu-tion, or vapor, the molecules are in a state of rapid motion and frequent collision. When the temperature has fallen so far. that it is possible for a crystal to exist, a few col-liding molecules may fail to rebound, and so become at-tached to one another, the balance between the attracting and repelling forces-between them causing them to arrange themselves on a space lattice, to which other molecules sub-sequently attach themselves. It was once maintained that the X-ray evidence demanded that the molecule should dis-appear in the solid crystal, but this was a wrong inference, and in many crystals, but not in all, the chemical molecule retains its identity in the solid state. In pure metals the atom and the molecule are identical, so that the conditions are unusually simple. How many. nuclei will be formed in a given mass is evi-dently a problem in probability. Experiments to deter-mine the relation between the temperature and the number of nuclei formed in a given time have been made with some success by using viscous organic substances, but metals offer much greater difficulties, and the few determinations which have been published are vitiated by serious errors. However, the examination of sections of ingots of the same composition and cast at 'the same temperature in similar molds will show, that the number of crystals does not vary widely.

Jan 3, 1927

By Stanley W. Sundeen

2.3-1. Introduction. The subject-"Preliminary Evaluation of Coal, Metallic and Industrial Mineral Deposits for Surface Mining'-seems at first glance to be definitive and not likely to be misinterpreted. Nevertheless, there are widely divergent opinions as to what is meant by "preliminary" and even as to what is meant by "evaluation." Some definition and qualification is necessary in order to provide a readily recognized basis for discussion. Evaluation evokes the idea of organizing extant data and judging its significance especially in the economic sense. It also may evoke the concept of the physical processes of acquiring the data that will characterize the deposit such as the geologic mapping, drilling, etc. Castle (5) considers that evaluation may embrace psychological aspects wherein human traits as, for example, over optimism might cause the evaluator to overlook obvious project weaknesses. In this chapter, evaluation is discussed primarily from the viewpoint of economically appraising a project from data available at a given point in time. The qualifying adjective "preliminary" is not easily defineable. In fact, some kind of evaluation proceeds, if not continuously, intermittently over the full span of exploration and early stages of development of a deposit. Bailly (1) comments: "Sometimes, before starting exploration in new areas or countries for a given commodity, we establish models to define what minimum combinations of re- coverable grade and tonnage are needed to give the minimum acceptable rate of return established by corporate policy. Then, before starting physical exploration in any target area we try and guesstimate optimistically what best 'geometry-grade-tonnage' can be expected. If these are acceptable in light of above minimum combinations, exploration is started as soon as funds are appropriated for the target area.''

Jan 1, 1968

(Separates of all the Pamphlets published within the last three years (starting with No. 1469) are available, with few exceptions, at Institute headquarters. Separates of all the Technical Publications are also available. All the papers are on file in public, university and technical libraries, and when so indicated in the list, may be found either in the TRANSACTIONS or in the special volumes issued by the Institute.] METAL MINING TRANS. PAMPHLET VOLUME NUMBER TITLE AUTHOR MEETING AND PAGE'S 1033 Relation of Air Pressure to Drilling H. W. Seamon New York 66, 743, 756 Speeds of Hammer Drills Feb., 1921 1034 Time Factor in Depletion of Mines J. W. Roberts New York 66,711 Feb., 1921 1035 Calculation of Ore Tonnage and Grade J. E. Harding New York 66, 117, 122 from Drill-hole Samples Feb., 1921 1038 Discussion of Papers Presented in 1920 1041 Run-off and Mine Drainage H. N. Eavenson New York 66, 624,630 Feb., 1921 1043 The Health of the Underground Worker A. J. Lanza New York Feb., 1021 1045 Dust-ventilation Studies in Metal D. Harrington New York 66, 272, 289Mines Feb., 1921 1046 Discussion of Papers Presented at New York Meeting, 1021 1072 Breakage and Heat Treatment of Rock- B. F. Tillson New York 66,1758 drill Steel Feb., 1921 1073 Discussion of Papers Presented at New York Meeting, 1921 1076-M Analysis of Some Drill-steel Testa F. B. Foley New York 66, 789 Feb., 1921 1077-M Application of Magnetic. Analysis to C. W. Burrows New York 66, 796 Rock Drills Feb. 1921 1078-M Heat Treatment of Rock-drill Steel G.H. Gilman New York 66, 779_ Feb., 1921 1080 What is the Ideal Drill Steel? F. H. Kingdon New York 66,807 Feb., 1921 1051 Rock Drill Steels, etc. - W. T. Ober New York 66,814 Feb., 1921 1082-C Underground Mine Development, Its J. B. Dilworth Wilkes-Barre 66,715, 7.21 Definition and Valuation Sept., 1921 1084 Drill Steel from Hollow Ingots P. A. E. Armstrong New York, 66, 809 Feb., 1921 1088 Authors' Replies to Recent Discussion 1092 Heat Treatment of Rock Drill Steel A. E. Perkins New York 66,811 Feb., 1921 1096-M Octagonal Ventilation Shaft. of Davis- J. L. Bruce Wilkes-Barre 66, 252, 268 Daly Copper Co. Sept., 1921 1100-C Determination of Electrical Equip- G. Bright Wilkes-Barre 66, 580, 605 ment for a Mine Hoist Sept. 1921

Jan 1, 1927

By A. K. Snelgrove

This symposium is designed to marshal a state-of-the-art account of approaches and solutions to problems arising out of waterlogging and salinization in the world's largest irrigation system which was dismembered by legal beheading of the Eastern Rivers under the lndus Waters Treaty of 1960. In this introduction, the geological and historical backgrounds of surface waters and groundwaters in the Indus Basin are presented with a summary of remedial measures undertaken and proposed to combat waterlogging and salinization. At a time when water-resource planning is proceeding on a continental scale, a study devoted solely to the Indus River Basin may seem to require an apologia. None is offered, however, for three major reasons: (1) Although the Indus is a single river basin, it is one of great magnitude and importance. The Indus River, which comes from Himalayan sources to form part of the great Indo-Gangetic Plain drainage system, is vital to agriculture and hydroelectric power in the thickly populated northern subcontinent of Indo-Pakistan. (2) The Indus has become a plexus of extraordinary problems since the dismemberment of the world's largest irrigation system of which it was a part. The break-up of this system occurred with the legal beheading of the Eastern Waters under the Indus Waters Treaty of 1960. (3) Th River Basin has been the target of a Herculean effort to contain the twin encroachments of waterlogging and salinization that now threaten it with a shortage of fresh water. The British irrigation system of barrages and canal on the Indus was a venture admirable in conception. Unfortunately, it is now a legacy burdened with unwanted consequences due to interference with the hydrological regimen, particularly the rise of water table occasioned by leakage. To cope with this situation, there has been a possibly unprecedented concentration of domestic and international engineering and scientific talent on the Indus and its problems (about a score of organizations by recent count). To marshal a state-of-the-art account of their approaches and solutions is the purpose of this Symposium. The coordinated effort now being made on a variety of fronts under the general supervision of West Pakistan Water and Power Authority (WAPDA) is directed toward the modification and control of interactions and relationships between geological materials — soils, water and its salt balance, and air —in what has been termed a huge "underground lake" in an alluvial basin. The problem is an intriguing one in that a highly complicated case history of river-course changes visible in the present surface must be projected downwards through Recent and Pleistocene sediments in order to decipher the environmental controls of deposition in terms of vertical and lateral variations in lithology and patterns. Such studies must be extended to compaction, deformation, and fabrics of the alluvium. Geohydrology is often defined as groundwater hydrology. As employed herein, it includes the distribution, quality, and behavior of surface and subsurface waters, including their evolution, vagaries, and geological, climatological, and botanical milieux." GEOGRAPHY The Indus (Sanskrit, Sindhu = river) rises at nearly 17,000 ft above the sea in the glaciers on the northern slopes of Kailas Parbat, Tibet. It is about 1800 miles long and has a total drainage area estimated at 372,000 sq miles. The average discharge is 196,000 cfs at mouth. Leaving the Plateau of Tibet, the river flows at a level which is miles above the sea, and in places miles below Himalayan peaks, in a structurally controlled northwestward course. Joined in this course by six tributaries and swollen by the melt waters of giant glaciers, it swirls about the base of the famous

Jan 1, 1970

By T. L. Joseph

LARGE deposits of manganiferous iron ores, representing several million tons of metallic manganese, occur in the United States. The Minnesota deposits of such ore-are of outstanding importance because of their size, state of development, ease of mining and proximity to the Great Lakes, which permits water transportation to steel centers. In' view of the fact that our steel industry requires large quantities of manganese, for which no satisfactory substitute-has been found, and because our reserves of ferro-grade ore are comparatively small, the development of methods that will make our large deposits of manganiferous iron ores available as a source of ferromanganese is an important problem. Realizing the importance of this problem, some years ago the North Central Station of the U. S. Bureau of Mines and the Minnesota School of Mines Experiment Station undertook jointly the development of methods for recovering the manganese content of manganiferous iron ores in a: form suitable for the production of ferromanganese, the 80 per cent. alloy indispensable in producing steel. Two types of manganiferous iron ores have been described in previous reports. I The brown ores are higher in iron and lower in manganese than the black ores; the black ores are more siliceous but contain less phosphorus. The utilization of the iron content of the brown ores in the production of steel appears to furnish the best basis for their treat-ment. The method of attack has been to work out modifications in iron and steel practice so as to recover manganese in the form of slag comparable to ferro-grade ores. The greater part of the experimental work has been conducted with a 6-ton blast furnace and a Y2-ton basic open hearth. This paper is devoted mainly to open-hearth tests in which high-phosphorus spiegel

Jan 1, 1930

By William Kent

Mr. ASHBURNER's paper on the Classification and Composition of Pennsylvania Anthracites, read at this meeting, well shows the need of new and accurate determinations of the heating value of these coals. A similar need exists for the determination of the value of bituminous coals, since the variation in quality of the latter is greater than the variation in anthracites. The recent extensive use of liquid and gaseous fuels, " patent" fuels, tan-bark, and other refuse fuels, also makes a necessity fix some correct method of determining the relative values of each of these fuels. Mr. Ashburner has recommended that tests of coals should be undertaken by the Second Geological Survey of Pennsylvania, and Professor Dewey, as stated in Mr. Ashbnrner's paper, has suggested a plan for tests of American coals, by the Smithsonian Institution, for which an appropriation by Congress will be asked. It is to be hoped that if any extensive series of tests of coals is carried on under either Government or State auspices, the erroneous methods of test which were followed by Professor Johnson in 1842, and by Quartermaster-General Meigs in 1882, will not be adopted.* The first requisite in determining the heating-power of a fuel is proper apparatus, such as has not been used in any of the tests of American coals yet reported. In the hope that more accurate means may be used in future tests, the writer desires to call attention to an apparatus which he has designed for the purpose. Not having had opportunity for making a trial of it, nor even of having it criticised by others, he does not offer it as the best possible apparatus; but if it contains any points of value, and leads to the design of still more suitable devices by others, the object of the presentation of this paper will be accomplished. The tests by Professor Johnson and General Meigs were made by evaporating water into steam in ordinary steam-boilers. A steamboiler of ordinary construction is not a good apparatus for determining the heating power of a fuel, for the following reasons:

Jan 1, 1886

By Stanley Herold

A FEW notes on the occurrence and significance of mud volcanoes in Colombia may be of interest at the present time, owing to the renewed activity in geological exploration of, the coastal regions bordering the Caribbean Sea. The best-known volcanoes are found a few miles from the seacoast. One is situated to the south of Puerto Colombia; the second, to the east: of Cartagena near the village of Turbaco; and the third, near the village of Puerto Escondido south of the Sinu River. Others. are reported in more inaccessible localities. Usually they stand 2 1/2 or 3 ft. (0.762 or 0.914 m.) above the surrounding ground at the crater, though several craters from 10 to 20 ft. (3.04 to 6.09 m.,) apart will often build up an extensive mound at low gradient. The shallow mound may cover 1/2 or 3/4 acre (0.2 to 0.3 ha.) with an elevation of 12 or 15 ft. (3.65 or 4.57 m.) at the center. The craters are formed of hardened blue clay; the inside diameters vary from 14 to 24 in. (35.56 to 60.96 cm.). The rim is continuous, except on one side where there is usually a cut 3 or 4 in. deep, thus allowing an overflow. The craters are filled to the rim-cut- with a thick mixture of blue clay mud and water, which is kept in agitation by escaping gas. Fig. 1 shows the bubble in the act of bursting and Fig. 2 the appearance of the surface of the viscous fluid a second or so later. The frequency of the explosions is determined by the weight of the column of fluid in the neck of the volcano, consequently, such explosions are not synchronous in a group of craters. Ordinarily, there are two or three explosions in about 3' minutes. The supply of gas is small but steady and sufficient pressure must accumulate before the bubble can enter the column of fluid. The water is derived from the surface and enters the sedimentary strata not` far distant from the volcano. During long dry seasons, as the supply of water fails the volcano dries and geyser action ceases.

Jan 7, 1919