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By Giovanni B. Barla, Stefan H. Boshkov

The block caving method is examined in this paper on the basis of experimental results and observations in the field, and through the use of numerical modeling by the Finite Element Method. The Grace Mine, developed by a panel caving method, served as a reference case. However, the results obtained and the simulation techniques which have been developed may find useful application in more general conditions as encountered in other mining operations by block caving. Following a brief description of the Grace Mine and of the mining method, the problems associated with the behavior of underground drifts at the production levels, during undercutting and caving, are addressed. The most important results obtained through monitoring of strains and loads in the supports of a runway are discussed, while giving relevance to the sequence of mining operations in the immediate vicinity. The most important geomechanical data, as provided for subsequent modeling, are described with reference to: (a) rock mass characterization and (b) in situ state of stress. Then, the numerical modeling procedures, developed by the Finite Element Method in order to predict the caving phenomena and the behavior of underground openings during undercutting, are discussed. Finally, an attempt is made to compare the pre- dictions of the numerical analyses with, the measurements carried out at the instrumented site. Suggestions as to how to improve the results both qualitatively and quantitatively are also given.

Jan 1, 1984

By John C. Smock

The question of the proper valuation of mines of iron ore was suggested to me by the difficulties experienced in getting answers for the United States Census Office, while I was engaged in the work of collecting the statistics of mines in New Jersey and New York. The answers to the questions relating to values of real estate of mine properties varied so greatly that it was necessary to revise them according to some general principles of valuation. Generally the returns of mine proprietors seemed to be too low. There were, however, examples of what would be termed excessive valuation. The subject appeared to be of practical importance, and led to the paper here presented. The following table of selected mine statistics is given, prefacing the discussion of the principles of valuation. It is in part made up of census returns and partly of data obtained directly from mine owners and managers. The mines which were selected for the several groups and mining districts include nearly all of those from which the more full and carefully filled returns were received, and are also representative of their respective districts. Hence the averages obtained from them become good types of these groups or districts. The mines of New Jersey appear in six groups, each containing from three to eleven mines, or, in all, thirty-four mines. The magnetic iron ores of New York are in four well-marked groups, and there are twenty-six mines in them. Then follow the red hematite mines of St. Lawrence and Jefferson counties; and, lastly, the brown hematite groups of Dutchess and Columbia counties, and those of the adjacent parts of Connecticut and Massachusetts. The whole number of mines represented by the table is eighty-eight, of which twenty-eight are hematite mines. The first column gives the value of the real estate; the second that of the plant; the third is the sum of these two, or the capital invested. Then follow the number of men employed, the amount of wages paid during the census year, and the value of materials used in mining and preparing the ores for market." The seventh column gives the total expendi-

Jan 1, 1882

By H. E. Rorschach

Activity in Oklahoma fields declined in 1938 from the banner year of 1937. During the year, 1768 wells were completed as compared to 2632 completed during the year 1937. The following tabulation sets out details regarding the wells completed during the year: These computations do not take into account the wells drilled for repres-sure and salt-water disposal, and other nonexploratory wells. Purchasers' reports filed with the Corporation Commission of the State of Oklahoma show a total of 168,789,229 bbl. of oil purchased from Oklahoma leases in 1938, or a daily average of 462,436, a decrease of about 25 per cent from the year 1937. The outstanding operation of the year was the further development of the Ramsey pool, in western Payne County, the producing horizon being classified as the Wilcox. This pool was discovered on the last day in the year 1937, by the Mid-Continent Petroleum Corporation drilling on a unitized block in see. 18, T. 18 N., R. 2 E. The map in Fig. 1 shows the development at the end of the year 1938. An important discovery of the year was the Champlin Refining Company's No. 1 Boehm, in Garfield County, sec. 4-24N-8W., the producing horizon being the second Wilcox found at a depth of approximately 6700 ft. This pool was assigned the name of Hillsdale. Some of the offsets to this discovery well had not come up to expectations at the end of the year, but the discovery seems to be important as indicating that the Wilcox sand is productive in the Anadarko Basin area, providing that the right structural conditions are present.

Jan 1, 1939

By Graham Bright

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

Jan 1, 1923

By B. Bernstrom

A 22-ft diam, 7-ft long, wet autogenous grinding mill was installed in the new Cretaceous plant of the Jones & Laughlin Steel Corp. to prepare crude iron ore for concentration in spirals and flotation cells. The paper describes the flowsheet and gives a description of the operating and metallurgical results that have been obtained. These results include capacity, horsepower, operating problems and a comparison of pilot plant results with those obtained in commercial operation. The Cretaceous plant at the Hill Annex mine of the Jones & Laughlin Steel Corp. was designed with a wet autogenous mill for grinding low grade iron ore so that it could be concentrated by spirals and flotation cells. The plant, on the west end of the Minnesota's Mesabi Range, went into operation in June 1961, and preliminary operating and metallurgical information describing the performance of this mill can now be given. The crude is lean ore from the Cretaceous iron foundation. This formation is a beach deposit of Cretaceous age that overlies the Precambrian direct shipping and concentrating ores. This rock in nature is not extremely hard but is quite resilient, resisting blasting in mining and size reduction in milling. It contains hematite as water-rounded particles and other fragments of the underlying iron formation and adjacent rocks cemented together by a high alumina-silica ferruginous matrix. It is interspersed with hard dense hematite agglomerates and also contains granite pebbles and boulders that were not cleaned off during removal of the surface. It has a 3.48 sp gr and in the stockpile the material consists of frag-

Jan 1, 1962

By R. R. Templeton

THE year 1924 was particularly notable in the petroleum industry of California as it was a period in which extensive town-lot drilling, with attendant overproduction and allied problems, virtually ceased and the industry returned to a nearly normal condition. Nearly all major field operations were conducted by large operating and marketing companies; in contrast to 1922 and 1923 field operations, when small promotion companies set the pace and forced the large companies to follow. The outstanding features of petroleum development were: 1. The three major fields of 1923, namely Huntington Beach, Long Beach, and Santa Fe Springs, declined from a production of 13,042,939 bbl., in January, to 6,764,417 bbl., in December, a drop of nearly 52 per cent: During this period, Huntington Beach declined 35 per cent., Long Beach 42 per cent., and Santa Fe Springs 63 per cent. 2. Methods of pumping deep wells were improved in some particulars; this contributed toward sustaining the productions of these three famous fields above what was predicted. 3. Of the fields producing previous to 1924, only three increased in production to any appreciable degree, during the year, as the result of bringing in new wells. These fields are Dominguez, Torrance, and Wheeler Ridge. Dominguez, discovered in September, 1923, produced 56,851 bbl. in January and increased regularly to a production of 1,641,042 bbl. in December. Torrance increased from a production of 972,261 bbl. in January, to 1,783,670 bbl., in May, and then declined to 1,393,215 bbl. in December. Wheeler Ridge, discovered in January, 1923, produced 23,254 bbl., in January, 1924, increased to a high of 33,678 bbl., in September, and declined to 27,430 bbl. in December. 4. Nearly all the production that had been shut-in during 1923 was opened in 1924, except some wells chiefly in Coalinga, Fullerton, and Santa Maria districts. The opening up of this shut-in production, combined with the increased productions from Dominguez and Torrance, were the chief factors that held the rate of decline for the state to a gentle slope.

Jan 7, 1925

By Kenneth K. Humphreys, Joseph W. Leonard, Robert L. Llewellyn, William F. Lawrence

INTRODUCTION Cleaning fine coal sizes utilizing air currents in machines as the primary separating medium is called dry concentration or pneumatic cleaning. In 1947 approximately 18 million tons (16.38 million mt) of bituminous coal were cleaned by air machines; in 1965, 25.4 million tons (23.1 14 million mt); but in 1975, only 7 million tons (6.37 million mt). Table 11-1 shows the tonnages cleaned of bituminous coal and lignite in the United States by various types of equipment from 1938-1963. Table 11-2 shows only tonnages cleaned by pneumatic methods from 1964-1975. The decrease in tonnage to approximately 7 million tons (6.3 million mt) is due to a higher moisture content in the mined coal and the greater difficulty in cleaning the coal by air. There also was a definite trend to load raw coal at the mines, especially the slack which is the most expensive to clean due to the dewatering and drying requirements. While there have not been any applications of pneumatic cleaning in the anthracite field, its use has not been fully explored. The same is true for lignite and subbituminous coals.

Jan 1, 1979

By Edward H. Robie

NEVER before have the annual company reports in the mineral industry field exhibited the typo-graphical art so abundantly as does the current crop. Time was when most company reports made a drab appearance and dry reading, mostly confined to financial data and text that gave little information to the public or technical men. Now, the dollar statistics assume less importance. Considerable information is given on what is going on at the company's plants, new equipment being installed, new methods, properties under development, ore reserves and grades, and similar information of interest to professional men working in the field. We have one suggestion for further improvement: The names of the officers and directors of the company are always given, but only a few companies give the names of the principal operating officials. We think, in the case of a mine for example, that the name of the general manager, his assistant, the mine and mill superintendents, and any other top operating officials who have been largely responsible for the success of operations, are worthy of mention. The reports are now widely read and this recognition is due them. Conspicuous among the annual reports that we happen to have seen, in point of typographical attractiveness, are that of the Texas Co., celebrating its fiftieth anniversary with a gold-plated cover and gold printing inside; and that of Noranda Mines Ltd., with a red and black cover that would attract attention anywhere. Comment on economics, taxes, and labor give an excellent picture of what our industry is facing. Consider the following, from the report of the Union Oil Co. of California:

Jan 1, 1952

By Milo Krejci

(Butte Meeting, August, 1913.) THE plant and quarries of the Inland Portland Cement Co. are located at Metaline Falls, Wash., about 128 miles north of Spokane, on the Pend Oreille river, and within 10 miles of the Canadian border. The plant is one of a chain of cement plants controlled by the Lehigh Portland Cement Co., of Allentown, Pa. Work on this plant was commenced in June, 1910, and was completed in April, 1911, but on account of some delays in 'the construction of the power plant, the works were not put into operation until August, 1911. Since then it has been in continuous operation and has furnished the Inland Empire with a high grade of cement. Fig. I is a view and Fig. 2 is a plan of the works. Water Power Development.-The source of the water supply for the hydro-electric plant of the Inland Portland Cement Co. is Sullivan lake, a body of water approximately 5.5 miles long and 0.5 mile wide, situated in the Kaniksu Forest Reserve. A wooden crib dam was installed so as to raise the elevation of the lake 25 ft., and the additional storage capacity was taken up by the diversion of Sullivan creek into the lake by means of a wooden flume, 0.25 mile long, 6 by S ft. in cross-section, and a ditch 1,200 ft. long. The water from the lake follows the natural water course to an intermediate storage reservoir, which was created by the construction of an earthen dam. This pond wits used in connection with the saw mill which was installed at this point. Besides the earth dam, there was also built a crib, at the point shown in the sketch map, Fig. 3. This crib dam is 35 ft. high. From this point the excess water follows the natural course of Sullivan creek to the Pend Oreille river.

Jan 7, 1913

By H. M. Howe

It has seemed to the writer that one important, and indeed sufficient reason, for our slow progress in learning the relation between the chemical composition and the physical properties of cast-iron, has been that the problem has not been attacked properly. It would be well to select the most probable working hypothesis which we can find, and proceed to test that hypothesis by comparison with observed facts, and by making new observations specially designed for such a test. Our first step, then, is to select the most probable working hypothesis ; and to attempt this selection, to state the hypothesis and its immediate corollaries, and to take some first steps toward testing it, is the object of the present paper. Its chief purpose is to bring the hypothesis to the attention of those who are more familiar with the evidence than the writer can pretend to be, and in a better position both to present new evidence and to discuss it. The hypothesis here selected is, that composition governs properties in the case of cast-iron, in the same general way and for the same reasons as in the case of steel, mutatis mutandis. This hypothesis, which of course makes no claim to originality, certainly seems reasonable and probable; its exposition and discussion are made easy by our existing knowledge of the constitution of normal or " carbon " steel; it therefore seems worthy of consideration.

Jan 1, 1902

By P. B. Liebermann

THE resistance to motion offered by mine cars is caused principally by: Rolling friction, flange friction, bending rails, bearing friction and wind resistance. With proper construction and with a fair amount of attention and care, that is, under favorable conditions, the first three items cannot be greatly improved. The wind resistance ordinarily is negligible on account of the slow speeds commonly used. The bearing friction, however, is a variable item, depending upon the design, the bearing material, the lubrication, the location (whether in wheel-hub or on car-body) and the alignment. Under the most favorable conditions the bearing friction will reach a lowest possible value. By the development of a successful anti-friction mine-car bearing this lowest value has been improved to such an extent as to affect the whole system of mine haulage. After being satisfied of their durability and certainty of operation, any investigation into the advantages of anti-friction bearings for mine cars will have to be based upon reliable information as to the saving in power of such bearings. While numerous tests have been made in this direction, the results have not always been convincing, principally because of the rather crude methods that were employed. These crude methods are the main cause of the wide variations existing in regard to the exact amount of the frictional resistance. Frequently an ordinary spring balance is used and the pull necessary to move a certain car or train of cars is obtained by a number of readings. Such spring balances necessarily have a coarse graduation and the continuous vibration and fluctuations to which they are subjected make them highly dependent upon the individual observer. Further, they must be frequently calibrated. Sometimes these tests were made without regard to acceleration, speed or even grade.

Jan 6, 1916

By R. C. Gifkins, A. Gittins

A. Gittins and R. C. Gifkins (University of Mel-houvne)— Evidence from somewhat similar experiments to those described in this paper has led us to the conclusion that possibility 2) of the four listed on p. 319 is a description of what happens in grain boundary sliding. That is, sliding is limited by accommodation deformation, it being necessary to the Continuance of sliding that this accommodation should take place. An example of such accommodation, though probably not the most important, is fold formation at triple points. The evidence and arguments for this point of view are set out in Refs. 14 to 16. In particular, an experiment with a lead bicrys-tall5 seems to support point 2) rather than 3). In creep of this specimen it was found that at least 90 pct of the extension of a zone 0.3 mm wide at the boundary was supplied by sliding at the boundary. The sliding was localized in a region at the boundary very much smaller than 0.3 mm, in fact, in a region too narrow to resolve optically. In poly crystalline Specimens&apos; there appears to be a surface effect, as found by Rachinger," but it appears that this may not manifest itself at low strains. "Low strains" means <10 pct for a Pb-TI alloy, <2.5 pct for magnesium or "Magnox" A12 alloy, or <40 pct for a 0 brass. Up to this extension the sliding, measured by the mean vertical step at boundaries, is proportional to extension. We are able to say this with some confidence, since the error bars on our points are statistically derived. Our results would lead us to think that the error bars on other work, including that of Mullendore and Grant, are much too large at low strains to show this

Jan 1, 1963

By Julius Pohlman

The history of Niagara Falls, as currently told, is simple, and by that very simplicity it has been rendered plausible. AS the story runs, the Falls were once situated at Lewiston, 7 miles to the north of their present site; and, since all the rocks in this section are alternate hard and soft strata, the waters acting readily upon the soft shales caused their removal, and the overlying hard lagers, deprived of support, broke down under the weight of the large volume of water that rushed over them; and this erosive action has sent the edge of the fall more and more southward, until it now has excavated the seven-mile gorge between Lewiston and the village of Niagara Falls. (See Fig. 1.) As early as 1790" we find this theory advanced in a description of this region; and it has been practically endorsed by subsequent observers, the most prominent of whom was Prof. James Hall, the State Geologist of New York, who surveyed the Falls in 1841, and gave the most exact description of their surroundings in the publications of the State Survey.? Not until 1883 was the correctness of the accepted theory of the Falls questioned.‡ The geology of the basins of the Great. Lakes, as elucidated by Newberry,§ Speneer,ll and others, has added largely to a clearer understanding of the life-history of the Falls. The investigators have shown us that Lake Erie, as a lake, is, geologically speaking, quite young; that its valley was excavated in pre-glacial times by a series of rivers; and that the Maumee, Sandusky, Cuyaboga, Alleghany and other rivers carried the drainage of the surrounding

Jan 1, 1889

By B. Silliman

THE remarkable outflow of natural gas recently developed in Western Pennsylvania, and along the valley of the Ohio and its tributaries, has called attention to an important series of patents for improvements in glass-fnrnaces and the manufacture of glass, which the brothers Siemens have made since 1872. The basement-patent of this series, is No. 127,806 of the U. S. Patent office, and is of date June 11th, 1872. This has been followed by eleven other patents (including one re-issue), all for improvements in glass-furnaces, or methods of manufacture, of which the latest is of date July 11th, 1882. Nine of these patents were issued in 1880-82. The following is the list of these patents, in order of dates, viz.: 1872. June 11th. No. 127,806 (U. S. office), Improvement in glass-furnaces; 17 sheets drawings, 5 pages text. This is the basement-patent. 1877. April 17th. No. 139,800. Improvement in the manufacture of glass; 3 sheets drawings, 2 pages text. Boats and floating vessels swimming in the liquid glass of the tank-furnace. Re-issued in 1880. q. v. 1880. April 27th. No. 226,931. Furnace for annealing and tem pering glass. " July 13th. No. 220,846. Glass-melting-furnace. " August 3d. No. 230,668. Glass-melting-furnace; 4 sheets drawings, 2 pages text.

Jan 1, 1885

By George F. Comstock

It has been known for many years that the alloy containing 90 per cent. copper and 10 per cent. aluminum can be hardened, like steel, by quenching from a suitable temperature, and that the hardened alloy can be softened again by annealing or drawing the temper. It does not seem to be generally appreciated, however, that the effect of the first slight reheating after quenching is actually increased hardness, the softening effect not taking place until a certain temperature of "drawing" has been exceeded. This paper gives the results of a few experiments on various specimens of cast 10 per cent. aluminum bronze, quenched for maximum hardness, and subsequcntly annealed at different temperatures. The hardness measurements were made with both a scleroscope and a standard Swedish Brinell machine; some peculiarities of the scleroscope test on this material are described. The author is not aware of many previous investigations of the hardness of this alloy when quenched and drawn, but two important papers on the subject should be mentioned. The earliest was by Portevin and Arnou,1 in which it was stated that tempering quenched 10 per cent. aluminum bronze at 400" C. increased the hardness as compared with the quenched untempered alloy and that reheating above that temperature &apos; was necessary to obtain any softening effect. A later paper was by Seidell and Horvitz,2 who mentioned Portevin and Arnou&apos;s work, but did not report any increase in hardness obtained

Jan 1, 1925

By R. F. Shurtz

The author proposes a method used with some success on a magnesite deposit at Gabbs, Nev. He believes this procedure to be more sound than the blind practice of assigning uniform quality to large, soinetimes vast blocks or ore on the basis of analyses made of a small number of samples. When an ore deposit is evaluated on the basis of core sampling, questions always arise as to how much weight should be given the various sample grades and how the deposit should be divided into specific volumes assigned to corresponding grades. For a tabular deposit it is customary to use the so-called zone-of-influence. This zone is usually defined as the polygon in the plane of the deposit having corners halfway between a given core drill intersection and each of the nearest neighboring intersections. The volume of the ore in this polygon is assigned the analysis obtained from the drill core taken at the intersection. In massive or irregular deposits, volumes of various shapes may be defined with respect to the locations of drill core samples. These volumes may be regarded as three-dimensional zones-of-influence; the theory involved in assigning the values of the central analyses to the ore in the volumes is the same as that used in the case of a tabular deposit. The zone-of-influence method was used in evaluating one of the magnesite deposits at Gabbs, Nev.&apos;-"

Jan 1, 1960

By F. L. Wolf, G. E. Alderson

The reclaiming of nietallics from slag and sweepings is of vital interest to every brass-foundry man, but the first cost and interest on the investment often make it prohibitive for the small foundry to enjoy the benefits of a complete concentrating unit. However, the cost of such an installation and the cost of operation are often exaggerated to such an extent that foundries dispose of their copper-bearing refuse at a great loss. This paper gives the actual costs and the returns obtained in the reclaiming plant used at the Ohio Brass Co. This plant is divided into two sections—the preliminary treatment and concentrating departments. In the former occur the screening, crushing, and hand-picking operations whereby rnost of the non-valuable and heavy metallic constituents are removed. The concentrating equipment consists of an elevator, bins, jigs, ball-mill, arid table. Preliminary Treatment The preliminary treatment varies, depending on whether the material is slag, foundry-floor sweepings, or brass casting-floor sweepings. Material of the first class is produced from the operation of six Steele-Harvey and six Schwartz furnaces; the second class represents sweepings from an average of thirty-five. molding floors per day: and the last is collected around the sprue cutters and knockout bench. Treatment of Slag The slag, analyzing 30 to 40 per cent. copper, is passed over a 3-mesh yard screen (Tyler standard mesh) stretched on an inclined rectangular frame supported by adjustable legs and equipped with a hopper which directs the undersize into a barrow. The fine product, running about 20 per cent. copper and representing 20 to 25 per cent. of the total slag, goes direct to a storage bin for concentrator frrd. The oversize is charged into a No. 2 Hill cinder crusher, which takes 175 to 200 11,. to a charge and crushes two charges per hour through &apos;a No. 4 riddle. It

Jan 1, 1921

By G. Das, S. V. Radcliffe

The substructural features developed in tungsten as a function of annealing temperature (up to 2200°C) and type of material [undoped and doped powder metallurgy (PM) tungsten and electron beam melted tungsten] have been investigated by transmission electron microscopy. For doped PM tungsten wires, characteristic "par-ticulate" substructural features developed rapidly with increase in annealing temperature above 700°C. The features consisted of parallel rows of elongated or circular shapes (500 to 1000A diam) lying along the direction of the wire axis and were identified as internal voids by diffraction contrast experiments. In recrystallized doped PM rod, larger voids were observed and were identified by precision dark field analysis to be cubic in shape and bounded by (100) planes. In marked contrast with both the doped PM materials, recrystallized undoped PM rod exhibited only very occasional and randomly arranged voids. Furthermore, no voids were observed in either material after electron beam melting. The high concentration of voids in the doped PM materials is attributed primarily to vaporization of doping additions or their pvoducts situated at the original grain boundaries , whereas the few voids in undoped material are considered to be traces of microporosity which were not eliminated during sintering. A tentative mechanism is suggested for the dezlelopment of the voids in relation to the processing sequences (sintering and working) and to the subsequent annealing. In recent years, a characteristic substructural feature consisting of rows of small elongated or circular regions of light contrast lying along the direction of working has been seen in thin foil electron microscopy studies of annealed sheet, wire, and rod tungsten. These features were present in the published micrographs of sheet by Weissmann et al.1 and of wire by Meieran and Thomas2, although the authors did not draw attention to them. Wronski and Fourdeux3 observed similar features in sintered rod tungsten (it was not specified whether or not the material was doped*) and interpreted them on the basis of their ap- particles, based on extraction replica evidence from the fracture surface of the initial hot-rolled slab material from which the sheet was prepared. No diffraction contrast experiments on the features were reported in any of these studies. The present investigation was undertaken with the primary objectives of: a) identifying the nature of these substructural features in tungsten by electron diffraction contrast experiments, since the contrast for voids can be expected to differ from that for crystalline or glassy particles, and b) elucidating the origin of the features and their development. For the latter purpose, doped and undoped powder metallurgy tungsten was obtained as rod and wire to represent different stages of reduction during final processing. These materials were examined both in the as-processed condition and after annealing to successively higher temperatures. In addition, the same doped and undoped materials were examined after vacuum melting in rod form. I) MATERIALS AND PROCEDURE Doped powder metallurgy (PM) tungsten wire (commercial purity 99.9 pct W) was obtained in the as-drawn and surface ground condition (0.030 in. diam "ground seal rod"). Doped and undoped tungsten rod (0.075 in. diam) representing an earlier stage of final processing was obtained from the same commercial source (Refractory Metals Division, General Electric Co.). Lengths of both the doped and undoped rod materials were single-pass melted in an electron-beam zone refiner to examine the effect of vacuum melting on the substructure. Annealing was carried out in a tungsten crucible in a tantalum strip resistance furnace under a vacuum of l0-15 mm Hg. Longitudinal sections of the wire and rod materials were examined by light and electron microscopy. The preparation of thin foils suitable for electron transmission from 0.030 in. diam tungsten wire and the rod specimens was carried out by means of a high-precision microjet technique developed to provide lack of jet stability and precise control of the area thinned. The method is described in detail elsewhere.&apos; The foils were examined in a JEM 6A electron microscope using a goniometer stage (±20 deg tilt, 360 deg rotation) and operated at 100 kV. To minimize contamination problems a 200 µ condenser aperture was used in conjunction with a useful beam current of 50 µA. II) RESULTS AND DISCUSSION A) Diffraction Contrast Analysis. In order to determine the optimum conditions for the development of the substructural feature, a series of isochronal 30 min annealing experiments were carried out on specimens of the doped PM tungsten wire. The transmission electron microscopy analysis showed that the as-drawn wire, Fig. 1(a), consists of &apos;fibers&apos; whose long axis is closely parallel to the wire axis of (110). The fiber width averages some 0.5 µ. Dense disloca-

Jan 1, 1969

By F. E. Bash

About three years ago, the writer presented a paper1 on the rate of heating and cooling of a 24-in. round ingot. The present paper deals with work done on larger ingots at the plant of the Allis Chalmers Mfg. Co., Milwaukee, Wis., in August, 1919. Sufficient data on ingots of all sizes were desired to enable one to calculate in advance the rate at which any ingot could be raised to a forging temperature without injury to the steel, determining also the temperature gradient between different sections of the ingot and the length of time necessary to heat to the center. This has now been experimentally determined for 24-in. and 45-in. ignots by the writer and for a 18-in. cube by E. F. Law.2 J. F. Harper has also made tests on heat-treating temperatures on 30-in, ingots; which data are included in this paper. No attempt is made here to work out a formula for the heat penetration of steel, for too many factors are involved concerning which we have not sufficient information, as for instance, the specific heat of steel up to 2300&apos; F. It is hoped that eventually a set of formulas will be developed so that one may calculate maximum allowable temperature differences within an ingot for any particular kind of steel and the rate of absorption of heat and temperature gradient within the ingot for a definite temperature head. EXPEEIMENTAL INGOT The ingot tested was 45 in. in diameter, having been forged into the shape shown in Fig. 1 from 54 in. diameter. Seven -in. holes were

Jan 1, 1923

THE opening session* was held in the hall of the Franklin Institute, on Tuesday evening, June 20th, President Holley in the chair. The President introduced. Mr. Franklin B. Gowen, who addressed the Institute as follows MR. PRESIDENT AND GENTLEMEN : It has been made my pleasant duty to welcome you to the city of Philadelphia, but in so doing I shrink, with some natural reluctance, from appearing before an audience so much better fitted than I am to cope with the subjects which are usually presented to your association, and I can assure you that no trembling neophyte, first venturing within the groves of the Academy, or walking, with sacred reverence, in the gardens of Plato, felt more natural dread at the consequence of his own temerity than I do in appearing before an audience composed of gentlemen belonging to a scientific society of which I am but too sensible that until now I have been a member only in name. In olden times, upon entering a temple sacred to the worship of any deity, it was customary to lay some offering upon the altar, and, in following this custom, it will be my duty, before entering upon the more pleasant part of the task which is assigned me, to call your attention to a subject with which I have been somewhat familiar, and which is entirely within the scope of your investigations, in the belief that I may throw out some hints or some suggestions of a pro¬cess that may be fully developed by some of you, and eventually lead to the introduction of that which may be of service to the human race. The satirist who described the philosopher whom he met, as engaged in the process of extracting sunbeams from cucumbers, * A joint discussion of the subject of Technical Education, by the members of the American Society of Civil Engineers and the American Institute of Mining Engineers, was held in the hall of the Franklin Institute, on Monday evening, June 19th, and Tuesday morning, June 20th. This discussion has been printed in a separate pamphlet by both societies.

Jan 1, 1877