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By C. M. Young

The safety lamp is the most common and convenient apparatus for detecting inflammable gases in mines, the presence of gas being shown by a blue flame, called the cap, if the wick has been lowered to suppress the luminous flame. The height of the cap increases with the proportion of gas and with the temperature of the lamp flame. Lamps of the Wolf type, the fuel of which is benzine, have a hotter flame than lamps in which vegetable oils are used, such as the Davy, and the Clanny, and are more sensitive than the latter and their many modifications. The Piehler alcohol lamp gives a still higher cap while the Clowes hydrogen lamp is most sensitive of all. While the effect of the temperature of the source of ignition is well known, the writer knows of no previous attempt to correlate the change of this temperature with change of the height of the cap produced, In order to determine the height of the cap at various temperatures, it was necessary to have a source of ignition the temperature of which could be accurately controlled over a considerable range. This condition was met by a coil of wire of high fusing point heated by an electric current controlled by a variable resistance. The use of a coil offered the further advantage of freedom from complications due to the flame of a burning fuel. Such a flame, being itself of variable height, would to some extent raise or lower the elevation of the base of the cap and therefore add to the difficulty of determining the height of the cap. Besides this, the presence of a small cap from the lamp fuel, commonly known as the "fuel cap," would interfere with the observation of small gas caps. After some experiment, a coil was made of platinum wire, No. 26, diameter 0.016 in. The coil was 17/64 in. (6.746 mm.) in outside diameter and had eight full turns in a length of 1/2 in. (12.69 mm.). This was connected to an electric circuit through an adjustable resistance, as shown in Fig. 1. In order to measure the temperature, a thermocouple was inserted in the center of the coil; the leads passed out at the ends and were ccnducted to a millivoltmeter. It is probable that the current of air passing upward through the coil resulted in the indication of a tempera-

Jan 1, 1920

By A. H. Tousley, C. L. Vickers

The author presents a history of the development of the Port of Long Beach from its beginning in 1905 to the present construction of a new bulk loading facility. In describing this new facility, emphasis is placed on such aspects as rail car and truck handling, gravity yard, rotary car dumping, bottom dumping, car dumping equipment, feeding and conveying, ship-loader-stockpiler, stockpiling and reclaim, dust control, and construction problems. Development of the Port of Long Beach, Calif. (see Fig. I), began in 1905. In that year private Long Beach interests acquired 800 acres of marshland in the Inner Harbor area and initiated a program of channel dredging and land reclamation. Efforts to establish a municipal port began a short time later and culminated in the opening of Pier 1 in 1911. An event of even greater significance to the port future also occurred in 1911. This was the tideland grant enactment by the state legislature that conveyed to the city of Long Beach all of the state's rights in the tidelands located within the city boundaries. The grant stipulated that all revenue produced from the tidelands be used for the development of navigation, commerce, and fisheries. During the next 15 years up to 1926, the port's commercial growth was steady, although relatively slow. During this period, several fundamental steps in the development of a major harbor were accomplished. These included the creation of the Board of Harbor Commissioners in 1917, the dredging of the Inner Harbor and entrance channel to accommodate deep draft vessels, and the correction of a serious silting problem through construction of the Los Angeles River Flood Control Channel. These efforts bore fruit during the ensuing 10 years in the establishment of more than $30,000,000 worth of industrial plants and private marine terminals in the Inner Harbor. Commerce over municipal wharves also increased more rapidly, and it became necessary to start the development of the harbor in a seaward direction. In 1936, oil was discovered in the harbor area, and the first Harbor Dept. well was brought in 2 years later. It soon became evident that the city of Long Beach would receive substantial revenue that, under the terms of the state grant of 1911, must be used in the development of the port. It was further realized that to properly guide and coordinate such development, a long range comprehensive plan was essential. The Board of Harbor Commissions contracted with G. F. Nicholson and J. F. Collins, consulting engineers, for the preparation of such a report that was completed in 1940. The Nicholson-Collins report proposed the development of an East Basin, between the entrance channel and the Los Angeles River, and a West Basin in the area now occupied by the Long Beach Naval Shipyard. Twenty full-size berths were to be provided in the East Basin and more than fifty berths in the West Basin. The report recommended extensive modern terminal facilities for handling waterborne cargo. Attention was given to improvement of the street and highway system to give better vehicular access and to avoid congestion within the port. To a large extent the recommendations of the Nicholson-Collins report were followed in the subsequent development of the East Basin. This development was greatly accelerated by World War 11, with its need for increased oil production and additional shipping facilities. The wartime and immediate postwar construction was largely concentrated on Pier A, with the development of Piers B, C and D following in more recent years. An important factor in the planning of these piers was their dual function as oil drilling sites and cargo piers. The Navy's acquisition of the West Basin area made it necessary to depart from the Nicholson-Collins plan and find other areas for future expansion. At the present time only one Inner Harbor Port-owned area having protected deep water frontage remains undeveloped. This is the property fronting on Channel 2 in the Inner Harbor acquired in December 1957, from Pacific Dock and Terminal Co. The growth of the port has been in a southerly direction since the construction of the Long Beach Naval Shipyard in the West Basin area. Recent extension of Piers F, G and J into the ocean follows typical port construction methods developed during the expansion of the Middle Harbor during the last 20 years.

Jan 1, 1963

By Charles A. Kelliher

In November of 1957, the Aliquippa Works started operation of the third basic oxygen furnace shop in North America. This high speed basic steelmaking method provided a very economical increase in capacity at the Works. The success of these two (2) 81-ton furnaces led to the construction of a second B.O.F. shop, producing heats of 230 tons at J&L's Cleveland Works in 1962. The experience gained operating both shops provided the background for the design of the new steelmaking complex at the Aliquippa Works. This new complex consists of a three (3) furnace shop with two (2) furnaces blowing alternately producing heats ranging from 120 to 207 tons. This variation in heat size is predicated on the requirement that approximately 20% of the shop production will be used to supply steel to a six (6) strand casting machine, producing 4' through 7" billets. The new B.O.F. shop has replaced all other steelmaking units including the #1 Shop, where operations were discontinued in September of 1968. With the advent of the strand casting facilities in September of 1969, many of the standard shop practices had to be changed to compensate for higher tap temperatures, longer handling times, and reduced ladle availability. The subsequent changes in these areas led to the evolution of the strand cast ladle practice which is described in this paper.

Jan 1, 1972

By J. S. Pascover, J. K. Abraham

The influence of the early stages of precipitation on the kinetics and structure of martensite formation in Fe-27Ni and Fe-29.5Ni alloys containing from 0 to 10 pct Ti was examined with X-ray and electron microscopy techniques. The formation of a coherent, ordered preprecipitate had a profound stabilizing effect on the austenite. The Ms was decreased by increased titanium content and aging time up to a critical time. When the critical aging time was exceeded, the Ms was observed to increase markedly. The formation of the clusters was insuppressible and the volume fraction of clusters formed during the quench was a function of the titanium content. Martensite resulting from transformation of the clustered austenite is tetragonal with the c/a ratio increasing with titanium content. A model for the tetragonality is suggested. The morphology and substructure of the m artensite is inter-preted in terms of the above information and the cur-rent models of twinned martensite. ThE ramifications of precipitation in austenite to the properties of austenite have been the subject of numerous investigations. The current research is concerned with the influence of precipitation in austenite on the kinetics and structure of subsequent marten-site formation. In a previous investigation, Abraham et al.1 followed the aging reaction in an Fe-29.5Ni-4.2Ti* (at. pct) alloy using an X-ray diffraction technique. This technique, employing a Guinier camera, provided kinetic measurements through observation of the side band position as a function of aging time. The salient results of this work were: 1) The initiation of precipitation was not suppressed by quenching, i.e., there was a finite cluster zone size at zero aging time; and 2) The hardness of the aged austenite correlated extremely well with the zone size. During the previous work it was noted that the mar-tensite formed after aging was tetragonal, substanti-ating an earlier observation.2 Systematic investiga-tion revealed that the martensite was tetragonal in both the solution-treated then quenched, and the solu-tion-treated, aged, and quenched condition, and, furthermore, that a marked stabilization of the austenite occurred as a function of aging time. The present work is concerned with documenting the tetragonality and the stabilization phenomena as well as the ob- served microstruction with a suggested rationale for the behavior noted. EXPERIMENTAL PROCEDURE The compositions of the alloys are listed in Table I. The analyses were performed after the solution treatment of the strip material. Nickel was determined using the standard dimethy1-glyoxime procedure whereas titanium was determined colorimetrically with hydrogen peroxide and volumetrically by titrating with ferric iron. The materials were melted in a 5-lb vacuum induction furnace, cast into 2-in.-diam ingots, and forged in a temperature range of 950. to 1200°C to 1/2-in. slabs. The three higher titanium containing materials cracked during forging; therefore, to get the alloys into strip form, slices 1/8 in. thick were cut from the slab, homogenized 4 hr at 1150°C, then cold-rolled to a 0.04-in. thickness. The remaining slabs were hot-rolled, homogenized 4 hr at 1065"C, then cold-rolled to a final thickness of 0.03 in. All of the heat treatments were performed under a protective atmosphere of argon. The Ms temperature for most of the alloys is below room temperature; therefore, it was possible to solution treat, quench to room temperature, polish, and then observe the transformation optically on a cold-stage microscope. To determine the effect of aus-tenitizing temperature on Ms, eight of the alloys were treated at two temperatures, 1025" and 1120°C. No measurable variations in Ms were noticed. The remaining alloys were treated at 1025°C. The specimens, : by 5/16 by 0.03 in., were austeni-tized in a vertical tube furnace under a dynamic argon atmosphere. The bottom of the tube was submerged in water for quenching purposes. The question of stabilization that may be operating at room temperature was investigated and found to be negligible. Many of the specimens were held at room

Jan 1, 1970

By WALTER M. DAKE

WITH the renewal of the contract between bituminous miners and operators, whereby a period of three years is assured without the devastating effect of irregularity of operation due to general strikes; and, with the increasing comprehension on the part of the large consumers as to the stabilizing effect of adequate storage upon prices; the coal industry has reached that period of its history in which permanence of purpose towards necessary changes is being crystallized, and these changes accomplished by the industry. It is to be hoped that during this era the phrase- " Our National Coal Problem "-will be relegated to the limbo of' antiquated expressions. That this epoch is upon us is evinced by the fact that operators are turning to consolidations, whereby financially sound companies will acquire smaller production units and place themselves in position to maintain constant supervision and control of their development and output; and, as further proof of the arrival of these changes, may be cited the entrance of additional members of the engineering profession into the many phases of management and operation, where- by the cost per ton of output will be, constantly reduced through the increasing use of modern methods and equipment. As an instance, attention is specifically called to the developments in mechanical loading, proposed and actual continuous underground transportation systems and betterment in methods of preparation.

Jan 1, 1924

By D. Harker, M. J. Murphy

The mechanism by which age-hardening takes .place is still not completely understood. The principal theories range from the extreme of "precipitaiion-hardening" to that of "order-hardening," with many intermediate gradations. In the hope of obtaining new data on which to base a choice among the many theories, the authors have made electron micrographs of formvar replicas taken from metallic specimens at various stages of age-hardening. The results so obtained on an alloy of 2 per cent beryllium in copper and one of 20 per cent molybdenum in iron will be described in the following pages, as well as the technique used in preparing the replicas. Preparation of Formvae. Replicas of Metallic Specimens This section is concerned with the techniques that have roved successful in preparing formvar replicas for studying the microstructure of metals with the electron microscope. Because of its simplicity and accuracy, the formvar replica1 method developed in the General Electric Research Laboratory has been used exclusively, since it is much simpler than the silica replica method of Heidenreich and Peck2 and produces as good results. The formvar method to be described requires a technique acquired only by practice, and no foolproof set of rules can be given. it is a rapid method and a replica can be obtained in less than five minutes under favorable conditions. This does not mean that perfect replicas can be produced every five minutes, but rather that one can well afford to take several strippings* in order to produce a replica of high quality. The metallographic technique required for replica work—very fine polishing and etching with very dilute solutions—is described here. It can be said, in general, that almost any surface that has been carefully prepared for a photomicrograph at 1000 or more diameters can be used to obtain a replica for the electron microscope. Preparation of Metallographic Specimens The preparation of the metallographic specimens is somewhat more exacting than that usually given to samples to be used for inspection under the light microscope. After much experimentation, it was concluded that the best method consists in polishing the metal through to the coarse cloth, then etching and repolishing on final cloth until the layer of distorted metal is removed. After this procedure has been completed, a dilute etch—to approximately the depth necessary for a micrograph at 1000 diameters—usually produces a sur-

Jan 1, 1945

LIST OF MEMBERS, ASSOCIATES AND JUNIOR ASSOCIATES ALPHABETICALLY ARRANGED ||Abad, Leopoldo F, College of Min, Univ of California Berkeley, Cal '23 ||Abarquez, Ramon F, Met, Bureau of Seience Manila, P I '24 ||Abbey, Robert Graham, Student, Case School of Applied Science Cleveland, Ohio '21 Abbort, A N , Mines Supt , Mazapil Copper Co , Ltd Concepcion del Oro, Zacatecas, Mexieo '23 Abbott, Clarence E , Gen'l Supt , Iron Mines Div , Tenn Coal, Iron & R R Co , 1405 Minnesota Ave , Bessemer, Ala '04 Abbott, Louis Benjamin, Chief Engr, Consolidation Coal Co, Elkhorn Div Jenkins, Ky '15 Abbott, Robert R , Met Engr , Peerless Motor Car Co Cleveland, Ohio '12 ||Abbott, Wells Osborn, Ray Consolidated Copper Co Hayden, Ariz '23 Abeel, George H, Jr, Cons Min Engr 4812 W 17th St, Los Angeles, Cal '18 Abel, Albert E, Asst to Pres, Valley Mould & Iron Corpn Sharpsville, Pa '19 Abeloff, Miran S Address Wanted '21 Abernathy, G E, Kansas State Teachers College Pittsburg, Kans '20 Abey, Hiroshi, Min & Met Engr. Takata & Co, 2 Yeirakucho, Niehome, Kolimachi-ku, Tokyo, Japan '17 ||Aborn, Robert H 24 Groveland St, Auburndale, Mass '19 Abouchar, Sylvain Sley, Min Engr & Geol , Care of S H Sekaly, 13 Rue El Nimr, Cario, Egypt '17 Abraham, Arthur W 1828 N Alexandria Ave, Los Angeles, Cal '20 Abrahams, A. I 115 East 82nd St. New York, N Y '14 ||Abrahamson, C. Walter, Min Engr, Brule Min Co Stambaugh, Mich '21 Abrams, Charles Jackson Columbia Bldg, Spokane, Wash '21 Abrams, David H, Min Engr, S E Dickey & Co, 809-11 Johnstown Trust Bldg, Johnstown, Pa '20 Acker, E 01C, Met 128 East Washington Lane, Germantown, Philadelphia, Pa '86 Acker, William L, Diamond Drill Contractor Mears Bldg, Scranton, Pa '18 Ackerman, Ernest R, Pres Lawrenee Portland Cement Co Plainfield, Union Co, N J '15 Adachi, Jinzoo 11 Shiba Park, Shiba-Ku, Tokyo, Japan '88 Adachi, Yuich, Meeh Engr, Anzan Steel Works, Anzan, South Manchuria, China, (Via Dairen) '21

Jan 1, 1923

By J. A. Roberson, Robert A. Rapp

From the observation of platinum wire marker movement in the oxidation of columbium at high lemperatures and low oxygen pressures, predonzinant cation diffusion in CbO, has been demonstrated. The Cu,0 molecule was used as an oxidizing species to study the nature of the porous scale and the location of the reduction site in the oxidation of colum-bium. The Cb205 scale contains microporosity and forms by alternate ionic diffusional growth and fracture. The oxidation of columbium at high temperatures and very low po, results in a relatively compact and protective Cb205 layer. THE observation of marker movements during oxidation is one means for the identification of the mobile ionic species in an oxide lattice. Previous marker experiments in the oxidation of columbium have all resulted in the markers being found on the outside surface of the Cbz05 scale. The Cr203 powder markers of Klopp et a1.,' the gold film marker of Kofstad and ~jijllesdal,' and the platinum wire marker of Cathcart et a1 .3 were found at the oxide/gas interface for oxidation temperatures ranging from 450" to 120O0C. However, in all experiments relatively high oxygen pressures were used. As discussed by Mrowec, even the interpretation of marker experiments in simple scales containing only one compound is not without ambiguities. In brief, it can be said that a marker may be found almost anywhere in the scale layer if the metal oxidizes by cation diffusion through the scale; the position of the marker depends upon morphological happenings in the scale. When considering marker movement in a polyphase scale one must proceed with extreme caution. For example, in the past (and present) work markers have never been found at the columbium-scale interface, and one might infer that the oxygen ion is mobile in CbO and CbO,. However, only trace quantities of CbO and CbOz have been present on any of the specimens, so no firm statement is justified on this basis. Despite previous experimental work, considerable doubt still exists concerning the role of the oxides CbO and CbOz in the oxidation of columbium. The identification of the mobile ionic species in CbO and CbOz from the observation of platinum wire markers was one goal of the present investigation . The linear kinetics of columbium oxidation at high temperatures (T - 1000°C) suggests that the Cbz05 scales which form on columbium are porous. From mercury absorption measurements on a Cbz05 scale formed at 500"C, Aylmore et al.' reported a minimum volume fraction of connected voids equal to 0.15. While these scales often appear to be quite porous when viewed in metallographic cross section, they are so brittle that metallographic preparation is likely to exaggerate any porosity originally present. In this investigation, porosity developed during the oxidation of pure columbium and present at the high temperature was detected by oxidizing specimens in sealed evacuated capsules containing large compacts of mixed copper and CuzO powders. wooda has demonstrated that the CuzO, or (CuzO),, molecule is volatile and that oxygen is transferred by the CuzO molecule from a Cu/CuzO mixture to materials having a greater affinity for oxygen. For each molecule of CuzO that is reduced at a sink for oxygen, two atoms of copper are deposited. Quantitatively, essentially all of the oxidation carried out by a Cu-Cu20 compact results from a displacement reaction involving the CuzO molecule. When a metal which oxidizes to form a porous scale is exposed to the CuzO vapor, the CUZO molecules are reduced in the pores leaving a deposit of metallic copper to mark the site of the reduction. This technique has the rather unique advantage that any copper-coated pores found in the scale are unambiguously related to the reduction site in the growth of the scale under consideration. Pores or cracks which form in a msition*- external to the reduction site or which occur as a result of cooling or handling of the specimen will not exhibit the copper deposit. EXPERIMENTAL PROCEDURE Marker experiments were made on columbium metal, and on pellets of CbO which had been pressed and sintered. Platinum wire markers (0.001 and

Jan 1, 1968

By Ronald W. Utley

INTRODUCTION The ''Do's and Don'ts" of installing equipment in a comminution circuit begin during the study stage of a proposed project, continue through preliminary engineering, detail engineering, procurement, the actual placement of equipment at the job site, and end with turnover to the owner. Equipment supplied for a modern comminution circuit will be high quality, rugged machinery designed according to appropriate manufacturing standards for long hours of trouble-free service. However, certain precautions and procedures must be observed in plant design and layout, equipment handling, installing and servicing in order to obtain optimum performance. This chapter contains general installation "DO'S and Don'ts" for the major equipment in the circuit. •Primary Gyratory Crushers •Rock Breakers (Hammer) •Belt Conveyors •Apron Feeders •Weigh Belt Scales •Secondary Crushers •Vibrating Screens •Grinding Mills •Mill Liners •Open Gear Sets •Speed Reducers •Electric Motors •Cyclones •Slurry Pumps Some questions will not be covered in this chapter, or may not be applicable to the actual equipment purchased, as requirements do vary from manufacturer to manufacturer. Additional specific information can be obtained by contacting the manufacturer's local representative or the factory. All inquiries should be accompanied by the following information: •Unit size and type of equipment •Manufacturer's shop order number (after order placement) •Serial number (after manufacture) DO'S 8 DON'TS FOR INSTALLATION OF ALL COMMINUTION CIRCUIT EQUIPMENT Installation By Design DO obtain tables of weights and clearances from manufacturer. DO obtain WR2 forces from manufacturer to determine that the foundation is adequate. DO determine compression strength of foundation soil and/or rock. DO obtain manufacturer's recommended typical foundation drawings. If substantial alteration to manufacturer's drawings is required, check with the manufacturer before proceeding.

Jan 1, 1982

By John K. Hammes

INTRODUCTION This introductory paper presents a description and definition of what the finance function is and what it specifically means for the mining industry. In its simplest terms, finance is, "management of money matters". As an area within the discipline of business administration it draws heavily on the related fields of economics and accounting, and to a lesser extent on marketing and production. MINING FINANCE DEFINED In preparing to write about what finance means to the mining industry, I asked a number of mining people the question, "What does mining finance mean to you?" Most responded that mining finance was "How a company borrowed money for mine development", and perhaps half those questioned included "raising equity" in the definition. It is not surprising that the mining industry concept of finance is the providing of funds needed for the objectives of the business, for that was once a view shared by authorities in the field of business administration. Further, it is certainly the area where much of the emphasis has been placed in the past ten to fifteen years as the industry struggled with the development of more remote and more refractory or lower-grade orebodies while profitability and internal cash flow were below expectations. No wonder project finance became such a popular topic. Twenty years ago it is probable that the emphasis would have been on mine valuation, for that subject was the area of finance then most often examined in industry publications. Papers concerning the pros and cons of payback, internal rate of return, and discounted cash flow appeared regularly. Let's examine the following situations, each the result of a financial decision: - Funding the exploration program in a developing country was accomplished by buying the next six-months budget needs in local currency. One week later the currency devalued 30 percent. If the purchase had been delayed or the local currency borrowed short term, a substantial saving would have been made in funding the program. - A major mining company borrows heavily to finance both expansion of its primary mining business and its entry into several new industry segments. When markets for all of the commodities it produces turn down for a prolonged period, there is concern over the adequacy of cashflow to cover debt service in addition to other company needs. The company's financial officers, however, had arranged very large committed credit facilities from numerous financial institutions which assured the availability of funds for several years. This enabled the company to implement a strategy to conserve cash, sell assets and survive until conditions improved. Further, short term suppliers of credit also were comfortable with the assurance that longer term credit was there to support them. -A medium size mining company financed several mines independently with limited obligations on the part of the parent company. The company decided to refinance the operations under one agreement. More flexible terms, lower interest cost and a longer tenor financing were achieved in return for assuming the risk as a direct obligor. - The exploration and development group of a large mining company proposes to develop a new mine in a country in which the company does not presently operate. When the investment is rejected they are advised that one reason was that the reinvestment assumption inherent in the discounted

Jan 1, 1985

OFFICERS AND DIRECTORS (The Officers are the President, 6 Vice-Presidents, the Treasurer, and the Secretary ) President and Director LEO F REINARTZ Middletown, Ohio Past President and Director ANDREW FLETCHER New York City President-elect and Director H DeWITT SMITH New York City

Jan 1, 1954

By L. D. Jaffe, H. C. Mann, E. L. Reed

The authors have recently published1 evidence that brittle transgranular fracture of polycrystalline metals does not originate at a point and propagate continuously across the material, but rather develops at numerous related points, leading to a series of micro-cracks which subsequently link up. Series of related microcracks were observed in steel specimens broken in fatigue—specifically, at the central portions which broke during the final sudden fracture. Microcracks of the type mentioned have also been reported by Baeyertz, Craig and Bumps'2 in steel broken under impact. % Some micrographs published by Irwin3 may possibly be interpreted as showing discontinuous brittle cracks. This paper presents additional observations of the authors on discontinuous crack propagation under various conditions. Impact Test Specimens The impact test specimens were cut longitudinally from a steel forging containing: The heat treatment consisted of oil quenching in a heavy section from 1600°F and tempering at 1260°F. The resulting yield strength was 78,000 psi, tensile strength 100,000 psi, elongation 20.0 pet in 2 in., and reduction of area 55.0 pet. Standard V-notch Charpy specimens were broken in a 217 ft-lb machine at a striking velocity of 16.8 fps. Energy absorption and fracture appearance of this material in the V-notch Charpy test are plotted as functions of temperature in Fig 1. After test, fractured halves of specimens appearing 0, 40, 80, and 100 pet fibrous (to the unaided eye) were electroplated with nickel, sectioned longitudinally (perpendicular to the notch at its midpoint), polished and etched with Cohen-Hurlich-Jacobson (C-H-J) reagent (picric acid plus Zephiran chloride in ethyl ether)4 or with Vilella reagent (1 pet picric plus 5 pct hydrochloric acid in ethyl alcohol).5 Fig 2 and 3 show cracks near the path of final fracture in the specimen rated 0 pct fibrous. Many of the cracks terminate at the boundaries of ferrite grains, some at boundaries of pre- existing austenite gzains. * A crack often starts near the end of another. Cracks within the same ferrite grains are parallel or approximately parallel in several cases. A large percentage of the cracks are branched. Fig 4 illustrated a group of cracks in the 40 pct fibrous specimen. Branching and parallelism are well marked. No more than three directions of crack have been observed on the polished surface in one ferrite grain. This is consistent with the evidence6 that brittle fracture of ferrite takes place on the cube face crystallographic planes: the {100} planes. The appearance of some cracks suggests that they have passed around a projecting corner of a second ferrite grain by going outside the plane of polish. In Fig 5 cracks in the 80 pet fibrous specimen may be observed. Some of

Jan 1, 1950

By R. F. Mehl, C. E. Birchenall

SINCE Maxwell1 first considered the self-diffusion process in 1872 its importance in the kinetic theory of matter has been recognized. Until the discovery of isotopes in 1913, a direct measurement of this quantity seemed impossible. The only information that could be gathered indirectly was for gaseous systems for which the kinetic theory was well developed. When methods of direct observation be-came available, investigations on self-diffusion were carried out in condensed phases. In metals these data are presumably of potential importance in the study of recovery, recrystallization, creep, sintering, and related phenomena. Following the pioneer work of Von Hevesy2 and his collaborators, who determined the rate of self-diffusion in lead with the naturally occurring thorium B isotope, several metals have been investigated. Pb, Ag³, Au.6,5, and Cu6,7,8,9 are examples of isotropic crystals existing in only one phase modification. Anisotropy of diffusion has been demonstrated in Bil6 and Znll. This paper is a study of a single metal in two allotropic forms and also of self-diffusion in a body-centered cubic lattice. Despite the fact that the measurements in each of the papers cited on self-diffusion in copper seem to be internally consistent to about 10 to 15 pet, the curves reported by different authors differ by factors of 2 to 4 at the same temperatures. This uncertainty may account, in part, for the failure to establish a successful correlation between the self-diffusion rates and other physical characteristics of the metals. No satisfactory theory of metallic self- diffusion has as yet been proposed to account for all the existing data and to permit estimation in other metals. Experimental Part: Two units of radioactive iron were used in these experiments, each a mixture of Fe53 and Fe59 (12). Fe53 decays by K electron capture and the emission of an X ray with a half life of about 4 years. Fe59 emits two beta spectra, one with a maximum energy of 0.26 Mev, the other 0.46 Mev, and gamma rays of 1.1 and 1.3 Mev, with a half life of about 44 days. They were present in nearly equal concentration initially. The composite half life started at about 50 days and increased as the Fe59 decayed, leaving Fe55 relatively more abundant. After aging a year, the half life was too long to measure significant decay in a month. The absorption properties also changed with time. Because of the importance of the absorption coefficient in the diffusion calculations, it was necessary to determine this quantity frequently over the period during which these experiments were carried out. This correction was unsuspected at the time of publication of notesl3 on this work and accounts for the discrepancy in alpha iron and for part of the discrepancy in gamma iron.* * The data in the present paper supersede those given in the notes entirely. In one note the scale of log D was inadvertently reversed. In addition to the correction for the drift in absorption coefficient, the D values for gamma iron at low temperatures were high owing to insuficient correction for diffusion occurring during heating and cooling through the high temperature part of the alpha range at a rate much slower than that employed in the runs reported here. The high temperature alpha rates are much higher than the low temperature gamma rates and correspond to large equivalent times at these temperatures. These experiments were discarded and new measurements taken. Independent experiments with the same activity units indicated a radioactive contaminant in the iron, but exhaustive attempts to isolate and identify it chemically failed. These experiments? indicate † These experiments will be discussed in a later publication from this laboratory. that the contaminant represented only a trace of little importance in the diffusion results. The active iron was plated from an iron chloride solution. Enough of the solution was dropped on a 1% in. square of filter paper to wet it thoroughly.

Jan 1, 1951

By Albert E. Wood, Edgar R Shepard

The interest of the Federal Government in improvement of waterways dates from 1820, when Congress appropriated $5000 for making a survey of the Mississippi and Ohio Rivers and assigned this work to the Corps of Engineers of the Army. Since that time the Government has gradually assumed increasing jurisdiction in the matter of improvement and control of inland waterways until, by the River and Harbor Act of Jan. 21, 1927, Congress assigned to the Secretary of War and to the Chief of Engineers the duly of making surveys, in accordance with House Document No. 308, 69th Congress, to formulate plans for the most effective improvement of the navigable streams of the United States and their tributaries, for navigation, development of water power, control of floods, and the needs of irrigation. Virtually all the preliminary investigations and surveys required by this act have been completed. The reports made to Congress have been published and often are referred to as ''308 Reports." The map shown in Fig. 1 is merely a skeleton distribution of the projects covered by these reports, but it serves to indicate the magnitude of the proposed undertaking. In many instances, a single character on the map stands for a major development involving several dams and reservoirs or many miles of canals or levees. The devastating floods of 1936, and the need for worthy public works to take up the slack in employment, gave further impetus to this program and in 1936 led to the enactment of a bill authorizing a large number of these projects. The National Flood Control Act of 1936 specifically authorizes some 270 flood-control projects in 31 states, and affecting nearly every state in the Union, with an estimated construction cost of about $300,000,000. In addition, the 1936 Act directs the Secretary of War to make preliminary examinations and surveys for flood control in some 230 additional localities, and to continue surveys and studies of 18 reservoir sites. The Corps of Engineers is proceeding rapidly with foundation investiga-

Jan 1, 1940

By Albert E. Wood, Edgar R. Shepard

The interest of the Federal Government in improvement of waterways dates from 1820, when Congress appropriated $5000 for making a survey of the Mississippi and Ohio Rivers and assigned this work to the Corps of Engineers of the Army. Since that time the Government has gradually assumed increasing jurisdiction in the matter of improvement and control of inland waterways until, by the River and Harbor Act of Jan. 21, 1927, Congress assigned to the Secretary of War and to the Chief of Engineers the duly of making surveys, in accordance with House Document No. 308, 69th Congress, to formulate plans for the most effective improvement of the navigable streams of the United States and their tributaries, for navigation, development of water power, control of floods, and the needs of irrigation. Virtually all the preliminary investigations and surveys required by this act have been completed. The reports made to Congress have been published and often are referred to as ''308 Reports." The map shown in Fig. 1 is merely a skeleton distribution of the projects covered by these reports, but it serves to indicate the magnitude of the proposed undertaking. In many instances, a single character on the map stands for a major development involving several dams and reservoirs or many miles of canals or levees. The devastating floods of 1936, and the need for worthy public works to take up the slack in employment, gave further impetus to this program and in 1936 led to the enactment of a bill authorizing a large number of these projects. The National Flood Control Act of 1936 specifically authorizes some 270 flood-control projects in 31 states, and affecting nearly every state in the Union, with an estimated construction cost of about $300,000,000. In addition, the 1936 Act directs the Secretary of War to make preliminary examinations and surveys for flood control in some 230 additional localities, and to continue surveys and studies of 18 reservoir sites. The Corps of Engineers is proceeding rapidly with foundation investiga-

Jan 1, 1940

By Richard W. Markley

The predominant methods for mining coal in the USA are room and pillar and longwall. Approximately 95 percent of the coal is mined by room and pillar and 5 percent by longwall. The U.S. Department of Energy (DOE) has an ongoing program to improve the rate, quality, and cost effectiveness of stabilizing the roof for both of these mining systems. In room and pillar mining, the installation of permanent roof support is often the task which paces the system operation, and it thus controls the level of production achieved during any mining shift. Two automatic roof bolt insertion equipment developments are discussed, as well as a flexible drill for operation in thinner seams. Progress will be reported on under- ground trials of a particular flexible drill which has been combined with a bolt inserter to form a compact, reliable module for retrofitting to continuous mining machines. In longwall mining, the use of hydraulic supports on the working face provides roof stability. The DOE has several trials ongoing with shield- type supports in difficult strata conditions which are described, as well as a co-funded project with the Bureau of Mines on a resin injection remedial method for consolidating a shear zone at one site. A project to improve the match of strata conditions to shield design is also described, which involves the use of a 1360 tonne vertical load mine roof simulator.

Jan 1, 1983

By J. W. R. Rayner

THE conventional method of making water gas involves individual plants for the separate carbonization of coal to coke and the subsequent gasification of coke with steam. The process demands lump coke, preferably made from the best quality of coking coals. The ash in the coke should have a high melting point and the gasification process suffers a loss of efficiency when cokes with law ash-melting points are used. In Britain, these coals are generally the most expensive and they are readily available only in certain localities. The coals not suitable for making lump coke, or yielding only poor quality coke, are much more widely available and are generally cheaper. DEVELOPMENT OF ALTERNATIVE PROCESSES In Germany, processes have been developed and operated commercially for the production of water gas from very low-rank coals such as brown coal and lignites, but much less effort has been spent on processes to use coals of intermediate rank, which are widely available in Britain. The brown-coal processes use coal in the form of either dust or briquettes. The most successful of the dust-gasification methods is the Winkler process, which made a substantial contribution to German oil production during the war. It uses coal in the site range 0 to 8 mm and the fuel bed is blown with a mixture of oxygen and steam at a rate high enough to give it a characteristic boiling motion or, in present-day phraseology, at a rate more than sufficient to fluidize it (Fig. 1). Air cannot be used to provide the heat required for gasification, for various reasons. In the first place, to make the process continuous by mixing air and steam would involve the production of a lean gas-containing much nitrogen. If a separate blow were used, a large amount of potential heat would be lost because the blow gas in such a process would contain a very high percentage of carbon monoxide. Oxygen is necessary therefore and oxygen remains relatively expensive for use in gasification. In the Winkler generator, formation of clinker caused by local overheating does not occur, because of the mobility and high heat transfer of a fluidized bed. These properties of fluidized dusts have been used most successfully

Jan 1, 1953

By J. L. W. Birkinbine

INTRODUCTION. This paper is a discussion of a part of the mineral wealth of the States of Oaxaca and Puebla, Mexico. It does not refer to the precious metals, some miles of which, in these States, are said to have been worked before the advent of the Spanish conquistadores in the sixteenth century, as my purpose is to invite attention to the exploration of deposits of coal and iron-ores in the Mixteca region. The prominence given to coal is warranted by the great effect of the scarcity of fuel upon the industrial development of Mexico. Under the progressive administration of President Porfirio Diaz, the Republic has made wonderful advances in the past three decades; and this progress would have been greater but for the limitations imposed by expensive fuel. In the spring of 1906 I was detailed by the Birkinbine Engineering Offices, of Philadelphia, to accompany A. B. Adams, of New York, in a reconnoissance of reported deposits of iron-ores in the State of Oaxaca. The result of this expedition was the formation, in 1907, of the Oaxaca Iron & Coal Co., of which Mr. Adams became, and has remained, President and General Manager, and I have spent the past three years as Chief Engineer of this company in Mexico, principally in western Oaxaca, where field-headquarters were established. GEOGRAPHY AND POPULATION. Although the geographical anti topographical, features of the Republic of Mexico are well known, few realize that the majority. of its population is domiciled in the States which immediately surround the capital city of Mexico, including the Federal District, Mexico, Tlaxcala, Morelos, Puebla,

Sep 1, 1910

By A. R. Marder

Fe-C alloys have been investigated at temperatures below the eutectoid transformation to determine whether the superplasticity phenomenon exists for these materials. As a result of void formation at the carbide-ferrite interfaces that led to void coalescence and premature failure, the large elongations characteristic of superplustic matem'als did not develop. It had generally been assumed that the conditions for obtaining superplasticity include: a) T/Tm =0.5, b) a strain rate sensitivity of the flow stress that results in m s 0.3, and c) fine-grain structure. Although superphsticity was not observed in the alloys studied, stress-strain rate measurements indicated that an additional condition for the existence of superplasticitv in Fe-C allovs is that the fine-wain structure be equiaxed in agveement with previous results on Zn-Al al1oys. MANY investigations have been made on the hot deformation of iron-base alloys in order to obtain an understanding of the variables that may affect high-temperature strength and ductility.'-6 However, only a few papers have studied the effect of carbon content on the high-temperature properties of iron-base alloys. Peretayat'ko and Zaikov and Wallquist and carlen4 studied the effect of carbon on strength in the y temperature range, and recently Robbins, Shepard, and sherby6 studied the influence of carbon on the torsional behavior of iron in the a and cu-plus-cemen-tite temperature ranges. In addition to studying hot deformation behavior, current investigations have also been concerned with the phenomenon of superplasticity in nonferrous materials, and, in particular, ferrous alloys. Superplasticity is identified by the increased resistance to necking that results from a high strain rate sensitivity of the flow tress. ackofenr proposed the strain rate hardening coefficient m = d log a/d log e as a measure of strain rate sensitivity and showed that m must be "-0.3 for superplasticity to exist. In addition, a fine-grained microstrcture,- a eutectic or eutectoid ornosition,- and a test temperature in the creep range (TITm > 0.5)" have also been advanced as necessary conditions for superplasticity. Although many workers""23 investigated superplasticity associated with the allotropic transformation in iron and the eutectoid transformation in steel, and recently chadler " and orrison have studied superplasticity in the a - y phase region, no one has measured the superplastic effect in the a + cementite temperature region. Therefore, the purpose of this investiga- tion was to determine the effect of carbon content, microstructure, and test temperature on the strain rate sensitivity of Fe-C alloys at temperatures below the eulectoid transformation. EXPERIMENTAL PROCEDURE Fe-C alloys with carbon contents of 0.2, 0.4, 0.6, 0.8, and 1.0 wt pct were prepared as 100 lb 54 in. ingots by vacuum-induction melting. The compositions are listed in Table I. All the ingots were soaked at 2100°F for 2 hr prior to rolling to 4 in. plate. The minimum finishing temperature for rolling was 1800°F. The plate was sheared in 10-in. lengths and tensile bars were rough-machined prior to heat treatment. The samples were heat-treated according to the schedule in Table I1 in order to obtain a fine-grained microstructure consisting of finely dispersed carbides in a matrix of small ferrite grains. All the tensile specimens were heat-treated prior to finish machining, and tensile testing was accomplished on an Instron machine in conjunction with a clamshell furnace. The buttonhead specimen configuration is shown in Fig. 1. An inert atmosphere, helium, was maintained during testing with a steel tube shroud in a bell jar arrangement. Predried helium was continually purged over the buttonhead specimens and exhausted through ceramic fiber at the bottom of the tube to keep oxidation at a minimum and to prevent

Jan 1, 1970

(SECRETARY'S NOTE.) The following discussion of the papers of Van Hise, Emmons, Lindgren and Weed, read at the Washington meeting, February, 1900, and printed on pp. 282 to 498 of this volume, comprises communications to the Secretary, received at various times before the Richmond meeting, February, 1901, and, for the most part, presented at that meeting. These communications are introduced at this point in the present volume, in order that they may precede the papers of Vogt, hemp, Lindgren, Rickard, etc., presented at Richmond, and therefore not forming part of the material considered in them. Since many of the contributors have mentioned in one communication several of the papers referred to, no attempt is here made to divide their remarks and distribute the fragments under separate headings. In each contribution, however, the several topics are indicated by subtitles. R. BECK,* Freiberg, Saxony : Prof. Veal Hise's Paper.-The paper of Prof. Van use (p. 282) represents a great step of scientific progress, in that the circulation of underground waters has never before been presented with such clearness, ill the light of modern chemical and physical knowledge. The theories of the formation of ore-deposits which follow the author's general survey of the currents and solvent power of atmospheric waters in the earth's crust do not, indeed, seem to be novel, being essentially an amplification of Le Conte's views; but the proofs adduced in their support are in many particulars so original that no one can read without profit this portion of the paper. Entirely new (though largely in agreement with the papers of Emmons and Weed, presented at the same meeting of the Institute) are the sections dealing with the formation of the rich sulphides of the precious metals, and especially the regeneration of normal sulphides, such as galena, etc., in vein-zones immediately beneath the ground-water level. Nevertheless, it appears to me that Prof. Van Hise, in the course of his most instructive exposition of unquestionable, yet still locally limited, phenomena, has been too much biased in favor of the " descensionists." This is indicated by the small importance which he attaches to the intimate genetic relation between epigenetic deposits and the plutonic hearths of the earth's interior.

Jan 1, 1902