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By Howard N. Eavenson

From the Pittsburgh coal bed in the four states of Pennsylvania, Ohio, Maryland and West Virginia has been produced an output that, at mine prices, represents a greater value than any other single mineral deposit in the world has yielded.12 While this distinction may in a few years pass to the gold reef of the Witwatersrand, it is possible that eventually, owing to the tremendous reserves still remaining, the ultimate yield of the Pittsburgh bed will be greater than that of any other known single deposit. Considering its importance, not a great deal has been written of its early history and development as a whole; most of the accounts have been of limited localities, or, at the most, of the area within a single state. In "Coal through the Ages" the writer mentioned some references to its early history, but this study will deal not only with its history but with the character of the bed, where and why it was first developed, and its effect upon the states in which it is found. It has not been the intention to write a detailed history of the development of the seam in each locality, as neither time nor inclination were available for doing such work, but only to show the influences that tended to hasten or retard such development. In general the historical matter ends about 1830, when geological surveys began to be made. Some of the maps show data available only since that time, and the sections about coal preparation and coking have been extended to the present time to show the changing conditions. It is believed that the early history includes all published records, and many more sources than those shown in the bibliography were consulted. It is quite likely that some references to coal in this area may be found in the unpublished papers of some of our early soldiers and colonizers, which exist in several libraries, and it is hoped that some future * Dedicated to Dr. Thomas S. Baker, President Emeritus, Carnegie Institute of Technology, whose labors in promoting the International Coal Conferences and in establishing the Coal Research Laboratory have done much in showing the industry how science can be of help to it. Manuscript received at the office of the Institute Feb. 15, 1938.

Jan 1, 1938

By Howard N. Eavenson

From the Pittsburgh coal bed in the four states of Pennsylvania, Ohio, Maryland and West Virginia has been produced an output that, at mine prices, represents a greater value than any other single mineral deposit in the world has yielded.12 While this distinction may in a few years pass to the gold reef of the Witwatersrand, it is possible that eventually, owing to the tremendous reserves still remaining, the ultimate yield of the Pittsburgh bed will be greater than that of any other known single deposit. Considering its importance, not a great deal has been written of its early history and development as a whole; most of the accounts have been of limited localities, or, at the most, of the area within a single state. In "Coal through the Ages" the writer mentioned some references to its early history, but this study will deal not only with its history but with the character of the bed, where and why it was first developed, and its effect upon the states in which it is found. It has not been the intention to write a detailed history of the development of the seam in each locality, as neither time nor inclination were available for doing such work, but only to show the influences that tended to hasten or retard such development. In general the historical matter ends about 1830, when geological surveys began to be made. Some of the maps show data available only since that time, and the sections about coal preparation and coking have been extended to the present time to show the changing conditions. It is believed that the early history includes all published records, and many more sources than those shown in the bibliography were consulted. It is quite likely that some references to coal in this area may be found in the unpublished papers of some of our early soldiers and colonizers, which exist in several libraries, and it is hoped that some future * Dedicated to Dr. Thomas S. Baker, President Emeritus, Carnegie Institute of Technology, whose labors in promoting the International Coal Conferences and in establishing the Coal Research Laboratory have done much in showing the industry how science can be of help to it. Manuscript received at the office of the Institute Feb. 15, 1938.

Jan 1, 1938

By John C. Calhoun, Alfred Chatenever

An exploratory study wap made to examine the possibilities of a visual approach in investigations into microscopic mechanisms of fluid behavior in porous media. Appropriate apparatus and techniques were developed so that microscopic phenomena could be recorded on color movie film as well as be observed visually. The observation flow cells in which tlie fluid behavior studies were made were essentially single-layered matrices of spheres between plates. sometimes all-glass, sometimes all-Lucite and sometimes a combination of the two. The fluids were limited to water and a filtered crude oil. Two flow regimes were observed during the flow of the immiscible liquids: channel flow and slug flow. In the former, transport was effected through stable networks of interconnecting channels; and in the latter, part of the movement took place in the form of slugs. Under certain conditions, flood-front patterns were found to be different depending upon which liquids were the displacing and displaced phases and not depending upon whether the matrix was water-wet glass or oil-wet Lucite. Residual formations of oil and water were observed and are described. Some of the ramifications and significance of the ohservetl phenomena are discussed. INTRODUCTION In recent years considerations of microscopic mechanisms of fluid flow in porous media have taken on greater significance. Much needs to be learned before the fundamentals of petroleum technology are completely established. For example, many unanswered questions exist in connection with relative permeability, displacement phenomena, residua! fluid formations. flow structure, etc.; and further analytical mathematical formulations are seriously indicated. It is hoped that systematic investigations into the microscopic mechanisms connected with the behavior of fluids in porous media will shed some light on some of the problems extant. Until recently microscopic mechanisms have been considered almost exclusively as speculative hypotheses. Within the past few years, however, the problem has been submitted to a limited number of experimental investigations. Nuss and Whiting' made some studies on the pore-space geometry of sandstones and limestones by impregnating cores with an inert plastic and leaching the solid matrices to leave behind plastic models of the pore spaces. SchaeferZ traced pore spaces microscopically through lengths of limestone cores by cutting away thin sections from the exposed faces normal to the line of view. In 1949 two projects were organized in which dynamic flow phenomena were examined microscopically to uncover microscopic mechanisms. One was set up at the Pennsylvania State College where Lowmanb bserved heterogeneous fluid flow phenomena in capillaries. The second was the American Petroleum Institute Research Project 47B at the University of Oklahoma where microscopic studies of dynamic fluid phenomena in synthetic porous matrices have been made by visual observation and cinephotomicrography.' It is with the latter that this paper is concerned. treating the techniques involved and the observations made. TECHNIQUES Observation Flow Cells The observation flow cells formed a focal point in the techniques employed. Essentially, these were matrices composed of a single layer of spheres sandwiched between two flat plates. This design was arrived at after a series of pre-

Jan 1, 1952

By T. J. Koppenaal

The surface slip line structure has been investigated by optical microscopy during the easy glide deformation of Cu-A1 single crystals as a function of composition, testing temperature and prior thermal treatment. The slip line structure in alloys of 2.5 or less at. pct Al is similar to pure copper, while alloys of 5 or more at. pct Al show slip tracings typical of a brass. Cross slip is observed in the "a-brass type" crystals and the amount of this type of slip increases rapidly with aluminum content. The cross slip tendency in 14 at. pct Al crystals is signicantly higher when tested at 150°C as compared to 4.2" and 77°K. In addition, cross slip is more pronounced in this alloy in the furnace cooled condition than when quenched from 450°C. The cross slip behavior is analyzed in terms of existing models for this type of deformation. In two previous investigations, reports of yield points1 and solid solution strengthening2 in Cu-A1 single crystals have been given. This paper enlarges upon the brief description of the slip line structure discussed in these reports. Since the easy glide slip line pattern of copper changes markedly with the addition of -30 pct Zn (-brass),3 a study of slip lines as a function of solute additions in Cu solid solutions should help to explain some of these differences. In addition to composition variables, slip lines have also been studied as a function of testing temperature and prior thermal treatment. PROCEDURE The slip line observations were made on single crystals of 0.5 to 14 at. pct Al using a light microscope. Details concerning the preparation and basic testing procedure are given elsewhere.' Prior to testing, each crystal was homogenized at 900°C for 24 hrs, furnace cooled, and electrolytically polished in a 60 pct phosphoric acid solution. The strain rate was-5 X 10 sec-I in each case. Unless otherwise stated, all observations reported upon here were made during the early stages of easy glide. RESULTS AND DISCUSSION The maximum magnification generally used was 1000X, and slip lines could be resolved down to about 105 cm (1000A). This resolution is appreciably less than obtainable with electron microscopy replica techniques where the replication can resolve slip lines down to about 40 A. Thus, while many qualitative features could be studied, the type of quantitative data obtainable with an electron microscopy replica study could not be made. Crystals containing 0.5 and 2.5 at. pct Al deform much like pure copper exhibiting a high density of fine slip lines that cover the entire gage length of the specimens. Fig. 1 shows the surface slip line pattern in a 2.5 at. pct A1 extended 0.01 shear strain at room temperature. Crystals having 5 to 14 at. pct A1 showed appreciably coarser slip lines that were generally concentrated at one end of the gage length. During easy glide these coarse slip lines propagate along the gage length in a manner similar to that observed in a-brass single crystals by Piercy, Cahn, and cottrel14 and refered to by them as a Lüders band propagation. Fig. 2 shows a typical area of these coarse slips in a 14 at. pct A1 crystal after a room temperature shear strain of 0.01. Two slip systems were apparently active. Using a method described by Cullity, the angles, between the specimen axis and the normals of the primary and secondary slip planes were determined to be 50 and 84 deg, respectively. 'From the Laue photograph, was 52, 81, 66, and 30 deg for the primary, cross, conjugate, and fourth slip planes, respectively. The secondary active plane in Fig. 2 is thus established as the cross slip plane, and the operative slip system is evidently the cross slip system, e.g., slip

Jan 1, 1963

By Edward H. Robie

THOUGH the final figures are not available as this is written, it seems certain that the Institute accounts will show $7000 to $8000 surplus for the year 1951. This is the first time this has happened since 1941. No money had to be taken from any of the Funds to bring about this happy condition. Furthermore, the amounts allowed for depreciation, bad debts, and inventory adjustment were more liberal than in the past. Income increased some $29,000 over 1950. Dues received from old members increased moderately, but dues from new members dropped off $2000 and from initiation fees quite severely-from $17,000 to $11,000. The number of new members did not come up to expectations and a change in procedure caused a delay in getting some of them on the rolls. A large number of the new members paid an installment of $5 on their initiation instead of the full $20. Junior Members, of course, pay no initiation fee. Brightest spot in the income picture was the increase in advertising income-from $103,000 in 1950 to $143,000 in 1951. All three of the journals shared in this, Mining being up $18,000; Metals, $9000; and Petroleum $13,000. Nonmember sales of the journals dropped off slightly, and sales of Transactions volumes more so from $35,000 in 1950 to $27,000 in 1951, with a further drop of $5000 accounted for by a change in accounting procedure. On the other hand, sales of other publications increased by $10,000.

Jan 1, 1952

By F. D. Wright, H. D. Fara

The solution to the plastic and elastic stresses around a circular shaft in a hydrostatic stress field that has appeared in two editions of a widely used book on rock mechanics1 is in error. Although this is a relatively minor matter, the correct solution was not found by a literature survey, so it appears worthwhile to present it. For a homogeneous, isotropic, rigid plastic-elastic body in plane strain which obeys Tresca's yield criterion the following equations must be satisfied:'," In the plastic zone,

Jan 1, 1963

By C. W. Gennet

Announcement was made in the spring of 1926 that the Boston & Maine R. R. Co. had contracted with the well-known German steelmakers, Messrs. Fried Krupp, for the manufacture of 15,000 tons of basic open-hearth steel rails at the Rheinhausen Works, for delivery to Boston, Mass. The manufacture of rails in the United States has for many years been almost a national pride, and as this feeling is chiefly the result of a long-time liberal and consistent patronage of American rails by American railroads, it is not strange that this somewhat unusual announcement should arouse more than ordinary interest. Since the end of the World War, the importation of foreign rail has been fairly large, principally because the newly created economic conditions have rendered some American competition more difficult, but the tonnage imported, for the most part, has been made up of small orders for miscellaneous use; and the contract referred to constitutes the largest single importation of foreign rail in over ten years. In 1915, the Algoma Steel Co. of Sault Ste. Marie, Canada, supplied the Illinois Central R. R. with 30,000 tons of rails,' and various other American roads with smaller amounts. In 1902, 1903 and 1904, large tonnages of rail from abroad were purchased, the Louisville & Nashville R. R. alone obtaining 30,000 tons from German mills. It is the object of this paper to present, in what is believed to be a new and concise form, figures showing the production and consumption of rails in the United States, and to record some of the testing and inspection results of the recent Krupp rails; also, to direct attention to two quite unique departures from American practice that were regular features of the Krupp process and which are worthy, it is thought, of careful study. Production and Consumption of Rails in the United States Table 1 shows the tonnage of rail produced in the United States and the amount imported, exported, and consumed by years since 1849. That, evidently, was the first year of record, for the statistics of the American Iron and Steel Institute and its predecessor, the American Iron and

By George H. Ashley

The Legislature of the Commonwealth of Pennsylvania at its last session passed a new act dealing with barrier pillars, which may have a wide interest in other states. In the past the laws of Pennsylvania have required that the superintendent of a mine "shall not permit the mining of coal within 50 ft. of any abandoned mine containing a dangerous accumulation of water, until said danger has been removed by driving a passageway to tap and drain off said water, as provided for in this act: Provided, That the thickness of the barrier pillars shall be greater aid shall be in proportion of one foot of pillar thickness to each one and one-quarter feet of water head, if in the judgment of the engineer of the property and that of the district inspector it is necessary for the safety of the persons working in the mine." Thus it has happened that a thickness of several hundred feet has necessarily been left in pillars in mining. It has seemed to many in the mining industry that this left an unnecessary amount of coal in pillars, and did not provide that the pillar be left equally on the two sides of the mine. As a result the General Assembly of 1927 by Joint Resolution authorized the Governor to appoint a Commission of "seven prominent citizens, of whom four shall be recognized mining engineers, one shall be a hydraulic engineer, one a geologist of recognized standing in his profession, and one a State mine inspector from the bituminous coal mining district, to investigate and report upon barrier pillars in the bituminous coal region." The Governor appointed the following Commission: Morris Coulter, Clearfield Bituminous Coal Corp., Indiana, Pa.; A. E. Roberts, Monroe Coal Mining Co., Revloc, Pa.; George T. Lewis, Westmoreland Coal Co., Irwin, Pa.; Morris Knowles, hydraulic engineer, Pittsburgh, Pa.; Thomas A. Mather, State Inspector of Mines, Tyrone, Pa.; A. B. Jessup, Anthracite Coal Operators Association, Jeddo, Pa.; George H. Ashley, State Geologist, Harrisburg, Pa. Mr. Coulter was elected Chairman and Mr. Ashley, Secretary. This Commission held meetings in Harrisburg, Johnstown and Pittsburgh. It obtained and considered the laws and experiences of other states and European countries. Some of its members conferred at length with the directors and other members of the U. S. Bureau

Jan 1, 1930

By M. Muskat R. D. Wyckoff

The phenomenon called "water-coning" is that, observed in many oil wells, in which bottom water gradually and frequently sudderlly displaces a part or all of the oil production when a certain rather critical production rate from the well is exceeded. To follow in detail the process of the formation of a water cone as it breaks through the oil zone and enters the well bore is a problem so complex as to make a theoretical analysis practically impossible. However, an analytical treatment of the flow system before the water has broken through and during the time that it lies statically beneath the oil zone with an elevated or "coned" surface can be carried through under certain approximations. To present an analysis which shows the essential characteristics of the coning mechanism is the purpose of the present discussion. Physical Basis of Theory and Meaning of Approximations As will always be true for flow systems where true water-coning is at all possible, the water will be supposed to lie beneath the oil zone because of its density contrast with respect to the oil. In fact, tinder the usual field conditions, when the pay horizon is reasonably homogeneous, the water most frequently enters the well through the lower zones, but even when it enters from intermediate zones it may, in the later life of the well, displace the bottom layers of oil, thus resulting in a system wherein the oil is effectively floating on the water.

Jan 1, 1935

By John V. Beall

One Sunday night last month the phone rang and it was George Schenck from Penn State. How would we like to see a big scrap operation, he wanted to know. A few days later we were on the Connecticut turnpike headed for New Haven to visit a large scrap operation, M. Schiavone and Sons. George had a large clam basket in the back which he explained was for collecting trophies. The car shredder, he said, turns out some fancy metal shapes. In fact, they have gained a certain acceptance as objets d’art among George's friends and relatives. He thinks there may be a small, but possibly lucrative secondary market for shredded cars in the art world if the idea is imaginatively promoted. On the way to New Haven we received a briefing on the scrap industry. The scrap business grew from humble beginnings. Mostly it was started by a few immigrant Jews who collected junk in hand- or horse-drawn carts. The fortunate one might even have had a truck. Before proceeding further, we hasten to point out that the word "junk" is strictly taboo among scrap people, who prefer to refer to their industry as the "secondary metals industry."

Jan 1, 1970

By Raja P. Upadhyay

An evaluation of the economics of mining the deep, thick oil shale deposits of the central portion of the Piceance Creek basin, Colorado, U.S.A. is presented in this paper. For the analysis, a modified large scale underground mining system developed by Cameron Engineers, Inc. and the Gas Combustion retorting process developed by the U.S. Bureau of Mines were used to determine capital investment and annual operating costs. A modified risk analysis computer program was then used to calculate DCFROI’s for various grades of oil shale and selling prices of partially refined shale oil. Sensitivity analyses were performed to quantify the affect of bonus bid payments, operating costs, capital investment, and all costs on DCFROI. In addition, a probabilistic evaluation was made to determine the risk involved in obtaining desired rates of return. Results of the economic evaluation indicate that for current selling prices of crude oil a high risk is involved in obtaining a DCFROI of 15%, unless only higher grades of oil shale are mined. However, mining only the higher grade oil shales, 125 l/mt (30 gpt) and above, would effectively reduce the potentially mineable resources by 90%. Risk can also be reduced through higher selling prices of shale oil. Sensitivity analyses indicate that the capital investment has a three times greater effect on required selling price than total operating costs.

Jan 1, 1977

By H. Herman, C. Chiou, M. E. Fine

From variation in Young's modulus and Vicker's hardness during GPl zone formation in A1-2 at. pct Cu the following was observed: 1) the presence of grain boundaries does not have any perceptible? effect on the aging reaction; 2) the modulus charge is orientation dependent; 3) the activation energy for zone growth is confirmed to be 11 * 1 kcal per mole; 4) reaging after reversion is preceded by an incubation time that varies with temperature. An analysis is applied to the present data and to data of other workers and kinetic laws dependent on the quenching rate are determined. In Al-base Cu alloys the decomposition product of a supersaturated solid solution at low temperatures (for example 25°C) and the first product at moderate temperatures (for example 150oC) are Guinier-Preston zones of the first kind (GPI).' These zones are nonideal and are thought Jo 'Onsist roughly of sheets of Cu atoms up to 150A in diam and one or two atoms thick.' The kinetics of the reaction, ass — a2

Jan 1, 1961

By Walter Crafts, W. D. Forging, John J. Egan

Although many elements reduce the tendency to porosity in steel castings, manganese, silicon, aluminum, calcium, titanium and zirconium appear to be most generally suitable for the purpose. The manganese and silicon contents are usually maintained in a fairly constant range. Silicon-killed castings often are made to be sound with little or no addition of the stronger degasifiers. In many cases, however, it is more practical to utilize the stronger degasifying elements, aluminum, calcium, titanium and zirconium. Since they greatly modify the composition, shape, and distribution of the nonmetallic inclusions, and thereby the ductility, the strong deoxidizers must be used in such a way as to form the least harmful types of inclusions. As the reasons for failure always to obtain good results have not been obvious, an effort has been made to determine the mechanism of solidification of steels deoxidized to produce certain types of inclusions. Diagrams representsing the mechanism of their formation have been constructed from the appearance of the nonmetallic constituents and have not only illustrated the limiting features of specific deoxidizing treatments with respect to inclusion formation and ductility, but have also indicated a relation between inclusions and resistance to hot tearing. Three different types of deoxidation treatment have been used for obtaining sound castings with relatively high ductility. The first method is to make and cast the steel under such conditions that deoxidation with silicon and a small addition of a strong deoxidizer assures soundness. The effective addition that will promote soundness without causing the formation of intergranular inclusions varies with the furnace practice and composition, but may be limitled to about 0.025 per cent Al, Zr or Ti. Up to 8.10 per cent Ca and 0.15 per cent V are also used for this purpose. The inclusions in these steels are characteristically glassy silicates and round or irregular sulphides. As pointed out by Sims and Lillieqvist,1 the formation of fine intergranular inclusions, which are detrimental to ductility, limits the amount of strong deoxidizers that may be added.

Jan 1, 1940

By John J. Egan, W. D. Forging, Walter Crafts

Although many elements reduce the tendency to porosity in steel castings, manganese, silicon, aluminum, calcium, titanium and zirconium appear to be most generally suitable for the purpose. The manganese and silicon contents are usually maintained in a fairly constant range. Silicon-killed castings often are made to be sound with little or no addition of the stronger degasifiers. In many cases, however, it is more practical to utilize the stronger degasifying elements, aluminum, calcium, titanium and zirconium. Since they greatly modify the composition, shape, and distribution of the nonmetallic inclusions, and thereby the ductility, the strong deoxidizers must be used in such a way as to form the least harmful types of inclusions. As the reasons for failure always to obtain good results have not been obvious, an effort has been made to determine the mechanism of solidification of steels deoxidized to produce certain types of inclusions. Diagrams representsing the mechanism of their formation have been constructed from the appearance of the nonmetallic constituents and have not only illustrated the limiting features of specific deoxidizing treatments with respect to inclusion formation and ductility, but have also indicated a relation between inclusions and resistance to hot tearing. Three different types of deoxidation treatment have been used for obtaining sound castings with relatively high ductility. The first method is to make and cast the steel under such conditions that deoxidation with silicon and a small addition of a strong deoxidizer assures soundness. The effective addition that will promote soundness without causing the formation of intergranular inclusions varies with the furnace practice and composition, but may be limitled to about 0.025 per cent Al, Zr or Ti. Up to 8.10 per cent Ca and 0.15 per cent V are also used for this purpose. The inclusions in these steels are characteristically glassy silicates and round or irregular sulphides. As pointed out by Sims and Lillieqvist,1 the formation of fine intergranular inclusions, which are detrimental to ductility, limits the amount of strong deoxidizers that may be added.

Jan 1, 1940

By William Victor Vietti

West Texas and New Mexico have been overshadowed by the dcvelopment in East Texas to such an extent that the area has been placed on a settled production basis by most of the operators. Considerable develop-mCnt work on both proven and unproven acreage remains to be carried 011, but the incentive, a ready and profitable market, has been lacking. The main characteristics of the fields in this area are so well known that they are not described again in this paper, which thus resolves itself into a statistical review of the more important production features of the area. Proration has been in effect during the year and has been rigorously applied with the full cooperation of all producers. Proration in West Texas and New Mexico is based in the more productive fields on a potential and acreage distribution of the allowance to the individual wells or acreage units. Potentials are determined generally by a short production test of from 1 to 4 hr.; and the hourly rate is multiplied by 24 to obtain the 24-hr. production or rated potential of the separate wells. The potential values thus set up have been questioned by many production men who are not willing to concede that the instantaneous (hourly) capacity of a well to produce is its potential capacity for a day with all other wells in the pool producing at their capacity. However, the potential of a well determined as above remains its chief rating as a measure of the permeability in place and as an indication of the possible reserve feeding that well. The acreage factor has made it unnecessary to overdevelop properties in order to obtain an allowance proportionate to neighbors who are willing to drill an excessive number of wells on a piece of acreage in the hopes of a quick drainage and a corresponding profit. Proration has resulted in an orderly development of many of the pools in this area on the base as outlined above, resulting in more reasonable spacing of wells and the more even withdrawal of oil and the ensuing expectation of high recoveries. Big Lake.—Production from the shallow or 3000-ft. pay at Big Lake totaled a little more than 3,000,000 bbl. during the year, and we may expect a smaller recovery for 1933. The deep or Ordovician production

Jan 1, 1933

By W. M. Brown

SEQUACHEE Valley includes portions of the counties of Marion, Sequachee, Bledsoe and Cumberland. It extends in a general direction parallel with the Great Valley of East Tennessee, some 75 miles northward from the Alabama state line. It is separated from the Valley of East Tennessee by a mountain arm about a dozen miles wide, known as Wallen's or Walden's Ridge. The genesis of the valley, geologically speaking, is simple. It is an erosion-valley along the axis of an anticlinal. The point of the wedge remains in a row of low "saw-tooth" hills, running up the center of the valley. These hills are of Lower Silurian age, and consist of Trenton limestone, covered and protected in some measure by chert. Walls of Carboniferous age form the inclosing mountains on either side; whilst a magnificent arch of Hudson River, Niagara, Hamilton and Subcarboniferous strata closes the valley at the

Jan 1, 1886

By W. C. Kerr

A brief sketch only is here intended, with a few illustrations, in order to give a general notion of the character and structure of these veins. I have stated elsewhere, several years ago, that these veins were wrought on a large scale and for many ages by some ancient peoples, most probably the so-called Mound Builders; although they built no mounds here, and have left no signs of any permanent habitation. They opened and worked a great marly veins down to or near water-level; that is, as far as the action of atmospheric chemistry had softened the rock so that it was workable without metal tools, of the use of which no signs are apparent. Many of the ladgest and most profitable of the mines of the present day are simply the ancient Mound Builders' mines reopened and pushed into the hard undecomposed granite by powder and steel. Blocks of mica have often been found half imbedded in the face of the vein, with the tool-marks about it, showing the exact limit of the efficiency of those prehistoric mechanical appliances. As to the geological relations of these veins, they are found in the gneisses

Jan 1, 1880

For the past several years the policy of a large section of our mining industry in relation to our present bureaucratic form of government has become increasingly amusing, if not a little disgusting. In the past, mining men have always featured themselves the self-announced champions of free enterprise, and, generally, this conviction, was substantiated by their deeds. In recent years, however, a large group of the industry, while still expounding, from the front porch, the principles of free enterprise and a sound economy based upon the law of supply and demand, have gone around to the back door with palm extended, to join labor, farmers, bureaucrats, and other pressure groups to get their share of the take. The procurement of subsidies, bonuses, increased metal prices, and government assistance in a multitude of forms seems to have obscured from their thinking the welfare of the country as a whole and the sounder economic principles of a balanced budget and lower taxes. At the recent Colorado Mining Association convention in Denver, I. was alarmed to see just how far this specialinterest type of thinking has progressed within the mining industry. Government assistance to mining. was generally considered inadequate, and a flat bonus for any new mineral discovery was proposed. It was disquieting, too, to learn how far the federal alphabet agencies have entered into the mining industry and of the thousands of highly paid technical. men on the federal payroll required to man these numerous overlapping agencies and bureaus. Now all this is very fine, and some aspects of the federal give-away program can be very appealing to the unsuspecting in the mining industry as they have been to those in other groups. Some of these expensive programs may bring about a few dividends or even several new mines. But to this whole line of pump-priming reasoning there is one big disastrous fallacy.

Jan 1, 1952

By B. T. Brady, Wilson Blake

One of the more widespread experimental procedures currently used in experimental rock and soil mechanics work involves the use of a short circular cylinder loaded axially between nonrigid end plates1-5 (Fig. 1a and b). It is widely recognized 6 that a number of undesirable features are connected with this test procedure ; the most noteworthy of these is the development of a nonuniform stress distribution throughout the specimen resulting from an elastic mismatch between the specimen and the end plates. In general, the end plates and specimen possess different elastic properties. As a result of this elastic mismatch, the uniform distribution of stress and strain applied to the end plates is altered at the interface, the degree of which is dependent not only on the magnitude of the elastic mismatch but also on whether there is any relative movement between the specimen and the end plate. A convenient measure of the elastic mismatch is the ratio (vp/Ep) / (v8/E3), where v and E are Poisson's ratio and Young's modulus and the subscripts s and p refer to the specimen and end plate, respectively. For most tests that use steel end plates, (v8/E8) is greater than (vp/Ep) ; i.e., the specimen tends to expand or contract laterally more than the end plates. Because of the frictional restraint offered by the end plates, shearing stresses are developed at the interface that, for compression testing, act inward producing a "clamping" effect (Fig. lc). The effect of this "clamping" is to produce a state of triaxial stress throughout the specimen. Fig. Id illustrates the coordinate system and stress nomenclature used. In a homogeneous, elastic two-dimensional plate loaded uniaxially at the edge, a uniform stress distribution is obtained at a distance from the

Jan 1, 1972

By L. F. Mondolfo, F. A. Crossley

The mechanism of grain refinement by the addition of small amounts of titanium, molybdenum, zirconium, tungsten, and chromium to aluminum was investigated. The results indicate that the grain refinement is caused by the peritectic reaction which, by transforming the intermetallic compound into crystals of aluminum solid solution, seeds the melt with nuclei above the freezing point of aluminum. THE feasibility of reducing the grain size of aluminum alloy castings by the addition of small amounts of titanium, zirconium, molybdenum, tungsten, columbium, boron, and chromium has been known for a long time, and the use of some of these elements as grain refiners is common practice in the aluminum foundry industry. The purpose of the present investigation was to determine the mechanism by which these additions produce the grain refinement. Asato et al., on the basis of extensive work on copper, antimony, and silver alloys, presented a theory of grain refinement based on the occurrence of the peritectic reaction. Briefly, this theory states that during cooling of the melt crystals of the primary phase form, which react peritectically with the liquid upon further cooling. The peritectic reaction transforms at least partially the primary crystals into crystals of the secondary phase, which then act as nuclei for solidification of the remaining melt. As the peritectic reaction takes place the primary crys- tals break in pieces, and each piece acts as a nucleus. Fine dendritic crystals which can easily break are the most effective for grain refinement. Sicha and Boehm," in investigating the refining effect of titanium on an AI-Cu alloy, concluded that TiA1, crystals serve as nuclei to initiate crystallization, but did not offer further information on the mechanism of refinement. Bonsack in the discussion of their paper suggested that refinement was due to clouds of some solid in the melt, probably TiO² which hindered grain growth. Eborall,' after studying the effect of titanium, zirconium, vanadium, tungsten, columbium, chromium, and boron on some alloys, concluded that the peritectic reaction was not an essential feature of grain refinement. Her conclusion was based mainly upon the observation that under her experimental conditions (sand casting) the Al-Cr alloys, which undergo a peritectic reaction, did not show appreciable refinement. Cibula" investigated the mechanism of grain refinement and reported that two types of grain refinement exist: 1—Grain refinement produced by restriction of grain growth by the concentration gradient mechanism proposed by Northcott.' 2— Grain refinement produced by the presence of particles in the melt, upon which the melt crystallizes easily. He further concluded that very marked grain refinement results from a combination of the two mechanisms. Since Tic was found present in aluminum alloys refined by the addition of titanium, it was identified as the nucleating agent. In the case

Jan 1, 1952