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By F. R. Zachar

IT has always been understood, in northern West Virginia where both the Pittsburgh and Sewickley seams are mined, that pillaring or splitting in the lower Pittsburgh seam could break the interval strata and make mining in the overlying Sewickley difficult or impossible. In some instances, however, mining methods practiced in the overlying Sewickley have reversed the problem, resulting in a shifting of the intermediate layer and destroying valuable acreages of the Pittsburgh seam below. The Pittsburgh seam in this area is, on the average, 102 in. thick. About 18 in. of low-quality head coal are left for roof protection as it is mined. Immediately over the coal are two draw slates, two rider 'seams, and a good hard black shale, locally called black rock, which serves as a permanent roof where draw slates and riders are taken down on certain main haulroads. In most areas mined in this seam in the past the bottom has been satisfactory but soft. However, in areas now being mined by the Christopher Coal Co. in Monongalia County the bottom is very hard and unyielding. The Sewickley seam, lying 85 ft above the Pittsburgh, will average nearly 70 in. in thickness and is overlain by massive shales and sandstones. Much of the seam is mined only down to the "sheep skin," a hard band about 4 in. above the bottom, which is composed of relatively hard shale. Fig. 1 shows a typical cross-section through the Pittsburgh and Sewickley seams in the area being discussed. The thin Redstone seam is not deep-mined but is stripped in some locations where it outcrops. Most of the Sewickley seam in the Morgantown areas has been mined out from 10 to 30 years. There are at present only two large mines and five or six others of small production operating in that seam. Mining systems in the past were generally of the room and pillar type with some full pillar extraction. This seam in the Scott's Run area was operated by as many as thirty or forty different companies at one time, during an era beset with strikes, market failures, and depressions. Most of the barrier pillars along the many main haulroads were abandoned, and blocks of Sewickley coal that would be fully recovered with today's machinery were left unmined when conditions became anything less than favorable. Consequently the mined-out Sewickley is spotted throughout with solid blocks varying in size from 100x100 ft to 200x400 ft and larger. It is these unmined Sewickley blocks surrounded by worked-out portions that have caused transmissions of roof stresses to underlying Pittsburgh mining areas, see Fig. 2, resulting in untold difficulty. As the Christopher Coal Co. operates both the Pittsburgh and Sewickley seams, accurate maps of workings in both seams are readily available and are regularly consulted. The first Pittsburgh squeeze attributed to overlying Sewickley blocks occurred in the Arkwright mine, where a shuttle car crew was developing a section consisting of seven panel headings. These entries were being driven in solid coal 3400 ft from the nearest worked-out Pittsburgh area. As mining advanced it was noticed that certain ribs began to slough and certain areas to show signs

Jan 1, 1952

By C. D. Broadbent

INTRODUCTION The slope stability research plan at Kennecott was developed to serve the specific needs of large, open pit mines; primarily those developed in faulted and highly-fractured intrusive deposits. The program emphasis is on applied research; being defined in this case as research into the engineering mechanics of discontinuous rock and into the related rock property survey and slope design techniques. The program has been developed in phases, with each phase organized to explore more thoroughly the most significant findings of previous work and to improve on techniques found to be applicable. The current work is based on principles developed early in the program and that show promise of having engineering and economic value. A brief summary of the conceptual principles of the program is given to put our current work in context. This is followed by a review of the two cooperative programs done with the U. S. Bureau of Mines. Most recent work is described and interpreted in terms of practical slope design. Although failure-free slopes are a desirable goal, it is recognized that some failures will occur when overall slope designs approach a calculated safety factor of one. A discussion of failure control research is therefore offered. BACKGROUND In 1965 Kennecott management specified that a slope stability technology must be used to achieve optimum development of ore resources. The subject was carefully explored and by 1960 it had been established that there was no technology readily applicable to open pit slope design. Therefore, in 1962, Kennecott Copper Corporation and the U. S. Bureau of Mines agreed upon a cooperative research program having the objective of developing a mine slope stability science. One of the first decisions made by the cooperating groups was that the research must be conducted primarily in the field and not in the unrealistic environments of a laboratory. Accordingly, the Kimbley Pit, an abandoned mine once operated by Kennecott's Nevada Mines Division in Nevada, was selected for the full-scale research. Fortunately, there was near-universal agreement on the basic stability parameters and thus on the areas to be investigated. These parameters were acknowledged to be: (1) anisotropy (generally due to faults or joints), (2) stress, and (3) water; in that order of importance.

Jan 1, 1972

By A. Josefsson

The transition temperatures of 0.01 to 0.02 pct carbon steels are shown to be strongly influenced by cooling rate in the a range, quenching from A, causing a very low transition temperature even after strain aging. In a titanium-stabilized steel and in a steel with 0.05 pct C this effect is absent. NORMAL mild structural steels usually show a structure of more or less pure ferrite, as a matrix, in which cementite grains or pearlite are embedded. Of these components, ferrite is by far the most interesting one as far as ductility and brittle (cleavage) fracture are concerned. Obviously, pear-lite and carbide are by no means necessary for a cleavage crack to nucleate and grow in the ferrite, as steels with a very low carbon content (Armco iron with 0.02 pct C) have an impact transition temperature just as high as semikilled steels with 0.26 pct C.1 Although it has been argued that a very embrittling effect is to be expected from cementite, precipitated as continuous films along the ferrite grain boundaries,'. " the micrographic evidence for a direct causal connection between the brittleness and these films does not seem to be very convincing. On the other hand, it has been stated that cementite particles in ferrite are able to stop ferrite cracks.4,5 In any case, the properties of the ferrite itself seem to be of overwhelming importance to the ductility of steels, justifying a thorough study of steels consisting of ferrite of different compositions, but principally free from pearlite, which means a carbon content below 0.02 pct. Such investigations have been carried out using the impact transition temperature as a criterion of the tendency to brittle fracture and have given some rather unexpected results. One result is the profound influence of carbon on the transition temperature of the steel in normalized condition. If the carbon content is reduced from 0.02 to 0.015 pct and below, a nearly discontinuous decrease in transition temperature appears even with high percentages of such elements as phosphorus and nitrogen present. This will be reported elsewhere." The present paper deals with another effect of carbon upon transition

Jan 1, 1955

By C. E. MacQuigg

MAN?S desire to harden metal is older than recorded history and obviously would date from the moment when he found his implements were not equal to the demands of service. This need for hardness in metal may be divided roughly into two main classifications: (1 :I need for hardness through- out-for purposes of greater strength or elasticity of the whole implement or member, and (2) need for surface hardness alone. A strong steel needed to transmit stresses or resist de- formation is an example of the first class. In metals only surface- hardened, the chief need is for resistance to wear. Obviously the whole gamut of all uses can be imagined- from the extreme of a simple cantilever supporting a load in space to that of a solidly supported face plate serving to resist wear. It is the in- creasing of wear resistance which I propose to discuss.

Jan 1, 1939

By David B. Reger

Exploration for new pools of gas in the Oriskany sand and continued exploitation of areas already known to be productive in that sand were the main features of petroleum activity in West Virginia during 1938. To a considerable extent the exploration program resulted in failure, but the extension of former areas was eminently successful. Throughout the state, in general, less drilling was done than in 1937. According to the West Virginia Department of Mines, only 631 permits to drill were issued, as compared to 1034 in 1937. The account of operations, as reported by trade journals and other sources, shows that 766 wells were drilled, resulting in 131 oil wells with 1609 bbl. of daily production; 484 gas wells with 1,232,216,000 cu. ft. of daily open flow; and 151 dry holes. Several discoveries indicate new pools of oil and gas; and several extensions of old gas pools have been made. In spite of a decreased number of total wells, the figures for new gas and oil are both larger than in 1937. The new oil average is 12.3 bbl. per well per day; the gas average is 2,545,900 cu. ft. per well per day, the ratio of dry holes to completions is 19.71 per cent. No general attempt was made to discover new pools of oil. A continued low price, coupled with reduced takings, combined to make drilling unattractive. The principal oil wells completed, by counties are: Boone, 6; Calhoun, 10; Clay, 7; Gilmer, 5; Kanawha, 5; Lincoln, 7; Pleasants, 13; Ritchie, 32; Roane, 6; Tyler, 7; and Wirt, 14. Production for the year, according to the Oil and Gas Journal, was 3,724,750 barrels. The leading counties in gas, with the number of successful wells in each, are: Boone, 16; Braxton, 13; Cabell, 47; Calhoun, 29; Doddridge, 10; Gilmer, 55; Kanawha, 127; Lincoln, 18; Ritchie, 29; Wayne, 19; and Wetzel, 26. Production for the year is estimated as 150,000,000,000 cubic feet. Pipe-line construction, which was extensive in 1937, was insignificant in 1938. Exploration was not as active as in 1937. Field prices of both oil and gas have severely declined.

Jan 1, 1939

By David B. Reger

Exploration for new pools of gas in the Oriskany sand and continued exploitation of areas already known to be productive in that sand were the main features of petroleum activity in West Virginia during 1938. To a considerable extent the exploration program resulted in failure, but the extension of former areas was eminently successful. Throughout the state, in general, less drilling was done than in 1937. According to the West Virginia Department of Mines, only 631 permits to drill were issued, as compared to 1034 in 1937. The account of operations, as reported by trade journals and other sources, shows that 766 wells were drilled, resulting in 131 oil wells with 1609 bbl. of daily production; 484 gas wells with 1,232,216,000 cu. ft. of daily open flow; and 151 dry holes. Several discoveries indicate new pools of oil and gas; and several extensions of old gas pools have been made. In spite of a decreased number of total wells, the figures for new gas and oil are both larger than in 1937. The new oil average is 12.3 bbl. per well per day; the gas average is 2,545,900 cu. ft. per well per day, the ratio of dry holes to completions is 19.71 per cent. No general attempt was made to discover new pools of oil. A continued low price, coupled with reduced takings, combined to make drilling unattractive. The principal oil wells completed, by counties are: Boone, 6; Calhoun, 10; Clay, 7; Gilmer, 5; Kanawha, 5; Lincoln, 7; Pleasants, 13; Ritchie, 32; Roane, 6; Tyler, 7; and Wirt, 14. Production for the year, according to the Oil and Gas Journal, was 3,724,750 barrels. The leading counties in gas, with the number of successful wells in each, are: Boone, 16; Braxton, 13; Cabell, 47; Calhoun, 29; Doddridge, 10; Gilmer, 55; Kanawha, 127; Lincoln, 18; Ritchie, 29; Wayne, 19; and Wetzel, 26. Production for the year is estimated as 150,000,000,000 cubic feet. Pipe-line construction, which was extensive in 1937, was insignificant in 1938. Exploration was not as active as in 1937. Field prices of both oil and gas have severely declined.

Jan 1, 1939

By JESSE L. MAURY

DEVELOPMENT of new gold mines in Canada since the price of that metal was increased in 1932 and 1933 has been of interest and importance to many of us. The day-by-day story has given an impression of aggressive effort and enough good luck so that the spirit of enterprise has been encouraged. It is the purpose of this article to report the results of a statistical appraisal which give emphatic numerical confirmation to this impression, together with certain side lights on the costs of development and equipment of new mines. The data presented have been taken from all readily available published sources up to the close of 1938 and are representative of that year. A. B. Bower did a large part .of the spadework and Weston Thomas offered many helpful suggestions.

Jan 1, 1939

By Richard E. Chism

If internal commotion can be called life, the Mexicans have certainly lived more in the last seventy-five years than any other people. To the oppression of the Spanish viceroys succeeded the sanguinary tumults of the Revolution of Independence, after which the Supreme Congress bequeathed its heritage of uncertain power to the empire of Iturbide, the only one ever established by Americans upon American soil, with an American at its head. That shortlived reign mas followed by years of ceaseless, bloody, and, to the superficial observer, meaningless revolutions—the deeper political and ecclesiastical significance of which it is beyond the scope of this paper to discuss. Then came foreign intervention, the ill-fated Austrian's brief supremacy, and the final triumph of the patriot cause under rugged old Benito Juarez, who crowned the victory of arms by a series of reforms breaking forever the temporal power of the Church and ushering in the calmer era which has lasted from the first accession of Diaz to the present day. During all those troublous times, the revolutionary ocean, that rolled so deeply over all other relics of Spanish dominion, had left almost unaltered the ancient laws of Spain, still lifting themselves above the tide, like landmarks of a flooded world. Many of these laws were obsolete ; some were absurdly inadequate to the demands

Jan 1, 1886

By AIME AIME

The Washoe plant, 1 in Anaconcla. Mont., together with the local street-railroad, ranches a. foundry and machine-shop a brick-plant and the Montana hotel, form a property under one management; to which should be added the mines in Butte owned by the company, from which part of the ore-supply of the plant comes. The Anaconda Copper Mining Co., controlled by the Amalgamated Copper Co., was reorganized under the laws of Montana in 1893. A map of the plant, showing the numerous departments and illustrating the details of tracks, pipe-lines, and charging-stations for compressed-air locomotives, is given in Fig. 1.

Jul 1, 1906

By R. T. McLamore

Lack of sufficient native permeability or skin damage caused while drilling wells for in situ leach mining projects may necessitate stimulating injection and production we1ls to increase the leaching rate to economic levels. Such stimulation processes could include acidization, hydraulic fracturing, or explosive fracturing. This paper describes an explosive fracturing process that is being developed primarily to stimulate the production of oil and gas wells, but may be useful in in situ leach mining projects as well. The process utilizes a liquid explosive that has unique safety features. The chemicals that form the explosive are subdivided into two pumpable, non- detonable components. Technology has been developed to pump these two components independently but simultaneously into the well and blend them together downhole to form the explosive. As such, surface facilities and personnel are not exposed to explosive hazards. The explosive formulations utilized in the process have been subjected to numerous safety and characterization tests and been qualified for use in deep wells with temperatures and pressures up to 250°F and 10,000 psi. The explosive composition can be varied to produce an explosive ranging, energetically, from a blasting agent to a high explosive that can be detonated after injection into a borehole, a porous media or into thin naturally occurring fractures within the roc

Jan 1, 1974

By Charles Will Wright

MINERAL production in almost all European countries suffered a sharp setback because of the war. Plants were damaged, transportation facilities disrupted, and labor dispersed and demoralized. Since the war, due to lack of confidence and economic stability, there has been little incentive to rebuild and expand the mineral industries even though a big demand at high prices exists for mineral products. Most mining and metallurgical companies in Europe hesitate to invest their capital because of the tendency towards nationalizing industry, high taxes, and low output of labor, as well as the deficiency of mine supplies and equipment within their countries. In short, they do not have faith in the future, and for these same reasons and fears most of the mining companies in America will not risk capital investment in Europe. In Europe, including the United Kingdom, free enterprise has been losing ground and as a result the foundation of their economic welfare is being undermined. American mining interests willing to take the initiative could help in counteracting this influence if a way were found for them to co-operate with the European producer without too great a risk.

Jan 1, 1948

By S. T. Wlodek

The scale md subscale reaction products were identified and their rates of formation were studied in air over the range 1600" to 2000°F (871 " to 1149°C) for periods of up to 400 hr and for hoth the solution-annealed and aged conditions. The effect of prior sltrface preparation on suhscale oxidation was also studied The general oxidation behavior of both Ni-Cr-Mo-Al-Ti type alloys was similar. A surface film of a, Al2O3, forms immediately on exposure Subsequent oxidation continued at a linear rate (QL = 55 * 5 kcal per mole) as colonies of Cr2O3 nucleated at the A12O3/gas interface Further oxidation proceeded at a paraholic rate zvhiclz could he fitted to two successive rate constants. During paraholic oxidation, and depending on temperature, the scale consisted of Cr2O3, NiCr2O4 , and TiO2 with traces of NiO. In the case of Rene 41, the activation energy of both paraholic processes was 66 * 3 kcal per mole suggesting that diffusion of cations tlzrozrgh Cr2O3 was the rate -determining process. An unusual decrease in the oxidation of Udimet 700 at 1900°F where a spinel of Ni(A1,Crh0, zuas the predominant reaction product prevented the accurate assignment of activation energies for this composition. In both alloys internal oxidation of Al2O3 commenced shortly after parabolic scaling was observed. Prolonged exposure prod7tced intemal oxidation of TiN, and in Udimet 700 a complex Mo-Ni nitride was also found. At 1900oF, the subscale reactions in Udimet 700 undergo an inversion which parallels the decrease in surface oxidation; internal oxidation ceases hut is replaced by the formation of "spherodized" 3.' colonies. Surface-preparation techniqtles which introduce appreciable working, such as coarse surface grinding or grit blasting. increase the amount of alloy depletion and internal oxidation in Reni 41. The reverse is true of Udimet 700 for which electropolished or mechanically polished specimens show much more subscale oxidation than strongly worked stirfaces. The strongest commercial nickel-base alloys presently available are generic to the Ni-Cr-Mo-A1-Ti base which exploits the precipitation of Ni3(A1,Ti) as the main strengthening mechanism, while relying on solid-solution strengthening by molybdenum and chromium reinforced by the pre- cipitation of carbides to attain maximum properties. This study characterizes the oxidation behavior of Rene 41, the strongest alloy of the Ni-Cr-A1-Ti type commercially available in sheet form, and Udimet 700, whose higher aluminum and titanium content allows it to exhibit one of the more attractive combinations of high-temperature properties available in a wrought product. The scaling processes of complex, type nickel-base alloys have received relatively little attention. Malamand and vidal as well as Poulignier et al.2'3 have determined the composition gradients across the metal/oxide interface produced by high-temperature oxidation and considered the effect of surface perature, Limited weight-gain data has also been published by Fere 5 for alloys of this type and Radavich6 has identified the reaction products on Udimet 500 and Inco 702 after oxidation at 1832°F. Reference can, of course, be made to the excellent reviews of Kubaschewski and Hopkins7 or Ignatov and Shamgunova8 for a summary of the data available on the oxidation of binary and ternary alloy systems which are related to the more complex alloys considered here. EXPERIMENTAL The analyses of the different commercial heats studied are given in Table I. Using the experimental procedures previously established,9 continuous weight-gain data were obtained on both heats of Rene 41 sheet (A and B) and 150-mil-thick slices of cast Udimet 700. Subscale oxidation reactions were followed by static exposure of cylindrical specimens obtained from swaged Rene 41 (Heat C) and Udimet 700 (Heats E and F). In brief, continuous weight-gain tests were performed on specimens with a surface area of 10 to 12 sq cm. These were abraded through 600 grit Sic paper, electropolished to 2p rms in an electrolyte of 10 pct H2So4 in ethanol, and lightly etched in 10 pct HCl in ethanol before final washing and rinsing in ethanol. All continuous weight-gain data were obtained in dried (-70°F dew point) flowing (1 liter per min) air to an accuracy of +0.1 mg. Subscale oxidation processes were followed by the metallographic examination of 0.5-in-diam by 1.0-in.-long specimens. After an initial center-less grinding, various additional surface treatments were employed to determine the effect of surface preparation on subscale oxidation processes. Before exposure in zirconia crucibles, all samples were lightly etched in 10 pct HCl-ethanol, washed in ethanol, and dried. The depth of internal oxidation was measured to ±0.00025 in. on unetched specimens mounted so as to provide a taper mag-

Jan 1, 1964

By W. M. Weigel

Economic deposits of barite occur in Missouri in two main districts. The most important, the Southeastern or Washington County district, is in the southeastern part of the state, mostly in Washington County with a small extension into the northeastern part of St. Francois County. Roughly, it embraces nine townships or about 200,000 acres and accounts for from 80 to 90 per cent. of the state production. The Central district, is in the central part of the state, includes most of Morgan and Miller counties, and parts of Camden; Benton, Moniteau and Cole counties. The area embraced is much larger than the Washington County district, but the deposits are more infrequent. The location and general area covered by the two districts is shown in Fig. 1. There is another small area in southern Franklin County but so far its production has been of small consequence. It might be considered as a northward extension of the Washington County field. An, area in the central part of Hickory County has also produced a small amount. The outline of the districts as shown indicates the general area in which deposits have been found. The total area covered by deposits of barite is only a small part of this, as, in the Central district especially, there may be miles of supposedly barren areas between ore-bearing areas of an acre or two in extent. The date when barite was first mined in Missouri cannot be definit stated, but the industry probably dates back to about 1860. The occurrence of barite was known long before this, as it was encountered in the lead mines in Washington County and mentioned by several earlier writers." Missouri is reported as producing 8000 tons in 1882 so it is evident the industry was well under way in the seventies in order to have arrived at this substantial production. By 1893 Missouri production had increased so that it ranked with that of Virginia, then the largest producer it increased until in 1914 Missouri accounted for about 65 per cent. of the total United States output.

Jan 1, 1929

By Magnus Troilius

INTRODUCTION BY C. P. SANDBERG. SINCE the discussion On steel rails in America has forcibly drawn attention to the value of chemical analysis, if not as a necessary stipulation, at least as a guide to control the usual mechanical tests, some doubt has been thrown upon the accuracy of the analytical results Obtained by different chemists. To any One having the least acquaintance with chemistry., it is quite clear that if exactly similar results are to be obtained from the same borings of steel, exactly the same methods must be used by the different analysts. Hence the necessity (if complications are to be avoided) of establishing what I may call standard or normal methods, to be used both by the inspectors and by the chemists at the works. Remembering that the application' of chemistry to steel-rail inspection is yet in its infancy, it is of great importance to possess a perfect acquaintance with the best methods in use. Being myself a grateful pupil of Professor Eggertz, of the School of Mines in Sweden, it Occurred to me, two. years ago, that I could not do better than start a laboratory of my. own, and engage One of his pupils, Mr. Troilius, for the purpose of analyzing the steel borings from mechanically-tested rails, so that I might thus Obtain without delay thoroughly accurate determinations. Moreover, in Order to carry on the, operations in perfect accordance with the methods used at the steel works in England and Germany, where I had to control the manufacture, I deemed it desirable to allow Mr. Troilius to go through a course of training at these works; and I gladly seize this opportunity of expressing my grateful acknowledgments to several works in England and in Germany for affording every facility for such an exchange of information as was found necessary in arriving at the best analytical methods to be used.

Jan 1, 1882

By C. W. Davis, L. R. Messer

THE name fuller's earth, which was derived from its early use in "fulling" or removing grease from woolen goods, is a term that is generally considered to designate mineral matter, containing hydrous aluminum silicates of the clay group, which has a high capacity for removing colors from oils, whether of animal, vegetable, or mineral origin. Fuller's earths are usually dried and may be "tempered" by heating or may be treated with water or reagents to improve their efficiency. For our purpose the term "acid-treated earths" will include those products from the partial decomposition of mineral water by acid which are equal to or more efficient than an untreated fuller's earth from Quincy, Fla., when used in bleaching mineral oil by the "contact" process. In general, the contact process for treating oils consists of heating and agitating a mixture of oil and finely divided adsorbent, the latter being subsequently removed by filtration. The term "adsorbent" is used because, although there has been a great deal of controversy over the mechanism of removal of impurities from oils by mineral matter, there is no doubt that adsorption, which involves the surface of the solid, plays a major part.' The properties that make fuller's earth useful in the treatment of petroleum products by "percolation1' and in the purification of edible oils by the contact process have long been studied, but the comparatively recent adaptation of the contact process to the bleaching of petroleum products has made desirable the further investigation of fuller's earth and other adsorbent earths.

Jan 1, 1929

By D. J. McAdam

In 1917 Haighl presented evidence that under simultaneous corrosion and cyclic stress metals may fail at lower stresses than if the corrosion is prior to the cyclic stress. In 1926 the author, while investigating the cooling effect of water on the fatigue resistance of metals, found that under these conditions steel specimens fail at stresses far below the endurance limit.2 (By "endurance limit" is here meant the fatigue limit obtained with specimens as free as possible from stress concentration and corrosive influences.) This led to an investigation (at the Naval Engineering Experiment Station, Annapolis, Md.) of the influence of cyclic stress on corrosion. This investigation may be divided into three parts. The first part was a general survey of the conditions necessary to cause complete failure under corrosion and cyclic stress of relatively high frequency. The entire process by which metals fail under these conditions was called LLcorrosion-fatigue." Corrosion-fatigue limits" for a large number of metals were determined and the relationships of these limits to chemical composition, heat treatment and physical properties were established. The conclusion was reached that corrosion-fatigue is due to the accelerating influence of cyclic stress on corrosion. Results of this part of the investigation were presented in five papers.*-= The second part of the investigation was a preliminary study of the influence of cyclic stress on corrosion. Each experiment was conducted in two stages. The first was a corrosion stage in which the specimen was corroded under cyclic stress; the second was a fatigue stage, in which the previously corroded specimen was tested (without further corrosion) to determine its fatigue limit. The difference between this fatigue limit and the endurance limit was used as a criterion of the "damage" due to

Jan 1, 1932

By Magnus Troilius

SINCE the discussion on steel rails in America has forcibly drawn attention to the value of chemical analysis, if not as a necessary stipulation, at least as a guide to control the usual mechanical tests, some doubt has been thrown upon the accuracy of the analytical results obtained by different chemists. To any one having the least acquaintance with chemistry, it is quite clear that if exactly similar results are to be obtained from the same borings of steel, exactly the same methods must be used by the different analysts. Hence the necessity (if complications are to be avoided) of establishing what I may call standard or normal methods, to be used both by the inspectors and by the chemists at the works. Remembering that the application of chemistry to steelrail inspection is yet in its infancy, it is of great importance to possess a perfect acquaintance with the best methods in use. Being myself a grateful pupil of Professor Eggertz, of the School of Mines in Sweden, it occurred to me, two years ago, that I could not do better than start a laboratory of my own, and engage one of his pupils, Mr. Troilius, for the purpose of analyzing the steel borings from mechanically-tested rails, so that I might thus obtain without delay thoroughly accurate determinations. Moreover, in order to carry on the operations in perfect accordance with the methods used at the steel works in England and Germany, where I had to control the manufacture, I deemed it desirable to allow Mr. Troilius to go through a course of training at these works; and I gladly seize this opportunity of expressing my grateful acknowledgments to several works in England and in Germany for affording every facility for such an exchange of information as mas found necessary in arriving at the best analytical methods to be used.

Jan 1, 1882

By C. H. Li, R. D. Carnahan, R. J. Stokes, T. L. Johnston

When silver chloride deforms by pencil glide at temperatures of 26ºand 72°C, grain size has no effect upon the proportional limit and the material necks down to a knife edge under tension. At -196ºC, deformation takes place on fewer slip systems to produce straight slip traces, the flow stress becomes sensitive to grain size and fracture occurs by cleavage from an intergranular source without any reduction in area. THERE are significant differences between the appearance of the slip bands formed in silver chloride and in the alkali halides at room temperature. The bands in sodium chloride, e.g., are fine and geometrically straight, whereas in silver chloride they are coarse and wavy.' Such differences in the slip behavior prompted us to inquire what the effects of grain boundaries might be on the mechanical properties of these solids. As an introduction to a general study of ionic poly-crystal behavior, we have investigated the effect of grain size on the stress-strain relationships in silver chloride at different temperatures. We have chosen silver chloride chiefly because polycrystals can be easily prepared free from cracks and macroscopic voids by conventional techniques. Moreover, as we shall see, the slip behavior can be readily modified by changing the temperature. It will be shown that the effect of grain size on the yield stress of silver chloride is strikingly dependent upon the temperature of deformation and that this temperature effect comes about through a change in the number of slip systems which operate at the onset of plastic flow. EXPERIMENTAL PROCEDURES Polycrystalline tensile specimens were made by recrystallizing cold-rolled AgCl sheet. Thirty-gram quantities of AR grade silver chloride powder were melted in a low heat capacity furnace, cast into cylindrical forms 3/4 in. in dim and approximately 1 in. in length and then extruded with a 16:l reduction ratio into rods 3/16 in. in dim. Extrusion temperatures were varied from room temperature to 350°C. In order to impart various degrees of cold'work to the extruded rod. All extrusions were then cross rolled to sheet 0.040 in. in thickness at room temperature and machined to form tensile specimens having a gage length of 0.750 in. with a width of either 0.250 or 0.145 in.* Annealing was carried out in an air oven at 200°C for periods up to 20 hr. specimens having average grain diameters ranging from 0.024 to 0.40 mm were prepared by varying the extrusion temperature and annealing time in the conventional manner. To obtain specimens with grain sizes larger than 0.40mm, lightly deformed thin prisims of silver chloride single crystals (supplied by Harshaw Chemical Co.) were recrystallized. Grain size determinations were made by an intercept method and revealed that the grains were equi-axed. Laue back-reflection X-ray patterns showed little tendency to form a preferred orientation texture. Specimens which were to be used for the slip band studies were polished by immersion in fresh boiling concentrated NH,OH for 60 sec. They were then etch polished for 10 sec on each side by hand lapping on a stationary velveteen lap wetted with a dilute Hypo solution (5 g of Kodak Acid Fixer in 100 cc H20). Finally the specimens were rinsed in warm water and alcohol, blown dry and carefully mounted in the tensile machine for testing. Tensile tests were performed at three temperatures, namely, 26º, -72º, and -196°C. A screw-driven hard tensile machine was used at a constant strain rate of 0.006 in. per in. per min. Loads were determined with a light- proof ring fitted with A-18 strain gages and extensions were measured with a 0.0001 in. dial gage. Constant level baths of alcohol with dry ice and liquid nitrogen were used to maintain the two lower test temperatures. EXPERIMENTAL RESULTS Reproducibility—In view of the light sensitivity and reactive nature of silver chloride, it was necessary to determine whether reproducibility depended upon either exposure to light or to the condition of the surface. However, during the course of the work it became clear that variation of laboratory lighting

Jan 1, 1962

By N. H. Jensen

SINCE the sixties, Utah has been one of the leading metal mining states of the Union. During the last fifteen years its mines have supported the largest smelting center in the world. Its rank as a metal producing state is reflected by its 1924 production which had a value in excess of $65,000,000 making it the leading silver producing state, third in both copper and lead and sixth in gold production. During the past year, metallurgical developments for the recovery of zinc contained in lead ores has made rapid progress so that the future zinc output will be of substantial importance. The largest silver mines of the nation and the world's largest open cut copper mine are within its borders. Settlement of Utah started in 1847, with the advent of the "Mormons," and originally the area of the state was much greater than now. The first metal mining

Jan 1, 1925

By A. H. Bell

DEEPEST hole in the earth, and deepest producing oil well in the world-such is well No. K.C.L. A-2, of the Continental. Oil Co., completed on April 12 in the San Joaquin valley about four miles west of Wasco, Calif. It penetrated the earth's crust to a depth of 15,004 ft.- almost three miles-a depth that exceeds by over 2200 ft. that of the previous record holder in western Texas. It is now producing oil from sands at a depth from 13,092 to 13,- 175 ft., which is about 1500 ft. deeper than the record formerly achieved in Louisiana. Continental's new well was bottomed in what is possibly Domengine-Avenal Eocene sand, and is producing from the Middle Miocene equivalent to the Rio Bravo sand.

Jan 1, 1938