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By John M. Lovejoy

NATURAL resources become a source of wealth as they are exploited and made available to the people in usable form. Experience has taught us that Nature does not readily give up her treasures, but the ingenuity of man in the field of techologic progress is required to find and efficiently exploit these resources. History has also demonstrated that with advancing technologic knowledge the. world has become progressively richer in its resources. Those that could not be commercially exploited are now being turned to beneficial use. Through expanding technology and the use of substitutes and synthetics, availability of the world's sources of natural wealth is today many times that of a hundred or a thousand years ago. And so it is with petroleum. Technology is also the great multiplier of our petroleum resources. Through improvements in the art of finding, drilling, and producing, our ability to meet rapidly increasing demands over the last quarter century has been maintained. On the other hand, had our

Jan 1, 1944

W. L. Saunders, New York, N. Y. (communication to the Secretary*):—The Laramie tunnel, though a small one, compares very favorably in the speed of driving with the great Alpine tunnels which have the record so far. I think it safe to say that, taking all things into consideration, the record made at Laramie is the best American record, though it still falls short of the long-tunnel records abroad. In discussing tunnel-records it must always be borne in mind that there are conditions peculiar to each individual tunnel job, so that no comparisons are complete, fair and conclusive. At Laramie there is one point which stands out prominently, and which distinguishes this from any of the recently-built Alpine tunnels, and that is that here we have great progress in an American driven tunnel without the use of a carriage for mounting the drills. At the Arlberg and Loetschberg tunnels, the carriage was an essential condition for progress. All the heading-drills were mounted upon a bar which rested upon a small carriage. This carriage was withdrawn after the drilling and run into the heading after the blast without much disturbance of the drills, and with very little adjustment except that required in jacking the horizontal bar across the tunnel. The carriage was so small in its track-area that it required little mucking to run it in to the face; and as the rock-drills used were heavy machines 38 in. in diameter, progress in setting up and drilling was very much accelerated by the use of the carriage. At the Laramie tunnel hammer-drills were used instead of piston-drills, and here we have an important distinction which

Jan 1, 1913

By Emil-Paul Lorenz

Considered as a whole, the mineral resources of the Turkish Republic (Anatolia) are in their untapped virgin state, and the little development shown is not the result of modern systematic geologic exploration but the continuation of the ancient open-pit mining methods of the Orient. When I came to Turkey in 1924, I found myself confronted by a formidable task because of the lack of preliminary geologic mapping. Today this condition has not essentially changed; less than one per cent of the country is covered by topographic mapping adequate for modern requirements. However, I was able to bring a semblance of order in a presentation of the mineral deposits of this country, by tracing the story of the mineral deposits that showed surface evidence of their existence. At present only the easily discovered mineral deposits of coal, copper, and lead-silver ores are being exploited. In the case of coal, of 3,000,000,000 metric tons available, only 100,000,000 have been mined. The same is also true for copper, lead-silver, and other ores, as shown in Table 1.

Jan 1, 1948

By Sherwin F. Kelly

FRONTIERS of geological knowledge retreated further this past year before an ever-widening geophysical attack, as governments and endowed institutions continued to take an increasing practical interest in the geophysical line of approach to the study of earth phenomena. A year ago I opened this annual review with a brief account of the efforts to discover what formations lie concealed beneath the deep sediments which form the superficial portions of the Continental Shelf off the eastern United States. That work was but the beginning, and 1938 saw its continuation and expansion. With the assistance of a Guggenheim Fellowship, Maurice Ewing pushed his researches in the development of instruments and techniques for deep-sea seismic refraction studies. Ewing's early refraction profile from the Virginia Capes to the edge of the Continental Shelf has been followed by a similar traverse in Great Britain from the coast of Cornwall to the edge of the Continental Shelf southwest of England. This showed that the thickness of the sedimentary mantle and the rates of slope of the basement surfaces there are comparable to those in the Virginia Cape district.

Jan 1, 1939

A HIGHLY successful joint conference on coal-mine transportation was held at Pittsburgh on Oct. 20 by the Pittsburgh Section of the American Insti-tute of Mining and Metallurgical Engineers and Mining Section of the Engineers' Society of Western Pennsyl-vania. C. E. Lesher, executive vice-president of the Pittsburgh Coal Co., presided over 215 members and others in the morning and Graham Bright, sales en-gineer with the Mine Safety Appliances Co., presided over about 180 in the afternoon. There were four prepared papers and much discussion, as well as a good luncheon between the sessions. Mechanical loading in the Pittsburgh district was discussed by L. E. Young, production vice-president of the Pittsburgh Coal Co. More companies in this district are using loading machines, more types of machines are being tried, and more coal is being mined by them than heretofore. The draw-slate above the Pittsburgh seam is the main problem; but devices for supporting and moving draw-slate are being tested. Except in two mines, the slate is being taken down. The fundamentals of the machines are similar, but the electrical drive and other parts have been improved. The problem is to recover or move as much coal as possible without hand labor. Methods of cleaning coal must be improved to meet the new methods of loading. The Pittsburgh Coal Co. has ten Joy machines and others are under order, a Myers-Whaley machine, Jeffrey conveyors, and Eichoff conveyors. The last mentioned are used in entries and other conveyors in rooms. At Montour No. 10 mine, one Joy machine is worked in rooms and one in entries.

Jan 12, 1927

By John W. Langley

In the summer of 1888 it was the fortune of the writer to present the subject of the desirability of establishing a set of samples of steel, which should be analyzed with extreme care, in order that they might become standards to which scientific and commercial analyses of iron and steel could be subsequently referred; also, that greater uniformity in the results of analyses might be brought about, since these standards would bear towards analytical methods somewhat the position which the original units of weight and length, the gramme and meter, or the pound and yard, preserved in Paris, London, and Washington, do to the mechanical arts. The plan met with hearty co-operation, with the result that com mittees were appointed in Sweden, Germany, France, England, and America, to receive the material and to see that the necessary au alyses were executed. In England, the British Association for the Advancement of Science appointed a committee, which subsequently published a plan

Jan 1, 1891

By R. C. Ku, A. J. McEvily, T. L. Johnston

The microplastic response of a series ofas-quenched Fe-Ni-C martensites has been measured at 77°K. At strains less than JO'3 the flow stress is governed primarily by the transformation-induced dislocation structure of the martensite. Only at strains in excess of 10-3 is the influence of carbon manifested in the flow stress. At these macroscopic strains, typically 10-2, the solid-solution hardening is proportional to (wt pct C)1/3, and, in an alloy containing 0.39 wt pct C, amounts to 50 pct of the flow stress. THE technological significance of high-strength ferrous martensite has stimulated many investigations of its structure and properties. Although our knowledge of the characteristics of martensite has increased immensely, especially with the advent of high-resolution techniques, an understanding of the basic strengthening mechanism still remains elusive. The purpose of the present paper is to consider certain aspects of micro-plastic behavior of Fe-Ni-C martensite which we feel can help to resolve this important problem. Such alloys are particularly suitable for experimental investigation because their compositions can be adjusted to reduce the M, to a temperature low enough essentially to eliminate the diffusion of carbon in the freshly formed martensite.1 The mechanical properties in this condition are of interest inasmuch as they reflect a state that is free of the important but complicating influence of precipitation processes. In this virgin martensite the carbon is distributed as it was inherited from the parent austenite; i.e., it is present interstitially, and gives rise to tetragonality through strain-induced ordering.' In order to determine the source of strength of such alloys, Winchell and Cohen1 investigated the low-temperature macroscopic stress-strain behavior of a series of virgin martensites of increasing carbon content but of common M, temperature (-35°C). They found that the flow stress increased rapidly with carbon content up to 0.4 wt pct; beyond this point the flow stress increased at a much slower rate. It was concluded that martensite is inherently strong. To account quantitatively for the strength of virgin or as- quenched martensite in terms of the role of carbon, Winchell and cohen3 suggested that the carbon atoms, trapped in their original positions by the diffusionless martensite transformation, interfere with dislocation motion according to a model akin to that of Mott and Nabarro. 4 In this treatment, individual carbon atoms are considered to constitute centers of elastic strain and thereby generate an average stress resisting the motion of dislocations throughout the lattice. The additional stress necessary to move dislocations, over and above that necessary for motion in a carbon-free martensite, is given by where L is an effective length of dislocation capable of motion. L was assumed to be limited to the spacing between the twins that are an essential structural element of Fe-Ni-C martensites. They assumtd the spacing to be invariant and of the order of 100A. However, recent work5 has shown that L is variable and can be in excess of 1000Å, so that the assignment of an appropriate value of L is not straightforward. In contrast to the above conclusion that there is an intrinsically high resistance to plastic flow, it has been suggested by Polakowski6 that freshly quenched martensite is in fact "soft" in the sense that dislocations are initially free to move upon application of stress. The high indentation hardness and macroscopic yield stress of ferrous martensites are then a consequence of rapid strain hardening that depends upon carbon in solution. Consistent with this point of view are the results of Beau lieu and Dubé who measured the rate of recovery of internal friction as a function of aging (tempering) temperature in a freshly quenched steel containing 0.90 wt pct C, 0.37 wt pct Mn, 0.1 wt pct Cr, and 0.07 wt pct Ni. The kinetics were clearly consistent with the idea that many dislocations are unpinned in the as-quenched state and that during aging they become progressively pinned by carbon at a rate controlled by carbon diffusion in the body-centered martensite lattice. In order to provide a basis upon which to distinguish between the "hard" and "soft" interpretations indicated above, we have made studies of the initial stages of plastic deformation in Fe-Ni-C martensites similar to those'used by Winchell and Cohen. It will be shown that the results support the contention that dislocation segments in as-quenched material are indeed

Jan 1, 1967

Discussions of the paper of Mr. Gayley read by title at the Lake Superior hieeting, but first presented at the New York meeting of the Iron and Steel Institute, October, 1904 (see p. 746). With the exception of Mr. Pourcel's discussion (p. 1038), these papers are here published under a mutual agreement between the Councils of the two Institutes, and will also be found, with others, in the Journal of the Iron and Steel In-slitute for the pear 1904, Mr. E. Windsor Richards, Past-President,' said that in 1799 Mr. Dawson, of Low Moor, read a paper before a scientific society in York pointing out the great diff'erence in the moisture of the air going into the blast-furnace in the hot months of the year and in the winter months. A cold blast-furnace was a very sensitive instrument, and showed this very clearly, for in June, July and August the furnace did not drive so well; it did not make the quality of iron and required more fuel; so that Mr. Gayley was on the right road to effect an enormous improvement in this direction. He considered that Mr. Gayley was on the way to great success, and hoped that the apparatus would not be a very expensive one. He supposed it mas too early for Mr. Gayley to let them know what the saviug was

Jan 1, 1905

By Blamey Stevens

(San Francisco Meeting, October, 1911.) My previous paper is entitled, The Laws of Igneous Emanation Pressure. The present paper lays no claim to the exactitude and completeness of a law, since it is of a provisional nature and may be disregarded when experiments have established a basis for more exact reasoning. The general physical states in which aqueous emanations may occur are first considered. The possible physical conditions under which the mineral elements may occur in emanations are then discussed, and a classification of deposits, dependent on emanation, is proposed. A system of scientific experimental investigation is outlined, and it is shown that the physical and chemical properties of emanation may be exactly determined thereby. The investigation is urged as feasible and simple, and not necessarily requiring large and costly apparatus. It is the only step necessary to make possible the formulation of a complete set of laws of igneous emanation. Process of Emanation. In a rising column, magma ranges in temperature from 900° to 1,200°C. Exhalation must begin at some fairly great depth. What this depth may be we can only surmise, since no experimental evidence is available. Exhalation, however, continues as the magma flows upward, until at another level the occluded gases have all escaped. This depth is probably upward of 5,000 ft. (See Fig. 1.) All exhalations must come from between these two levels. As the whole emanation is the sum of the exhalations and residues, the residues must come from below the uppermost level. They will be most abundant when coming, from those parts of the intrusion which have solidified below the lower level.

Apr 1, 1912

By R. W. Diamond

Low-grade ores can be designated by two main classifications: (1) simple low-grade ores, and (2) complex low-grade ores. As a rule the first type has a relatively small metal content, although low- grade iron ores contain a rather high percentage of metal. As the simple type is the one that is ordinarily in mind when the term "low-grade ore" is used, the paper will be devoted mainly to ores in this general category. Cheap treatment is the prime requirement in utilizing low-grade ores of the simple type, although in some cases the value of nonmetallic by-products, such as limestone for fer- tilizer and silica for flux, allows a little more lati- tude than in the usual situation. When the costs are divided under the three headings-mining, milling, and smelting-it is apparent that the last group will not constitute an important factor as a rule because the high concentrating ratio makes the smelting cost per ton of ore fairly low.

Jan 1, 1949

By H. B. Probst

Mechanical twins were produced in zone-refined tungsten single crystals by explosive working at room temperature. These twins are parallel to (112) planes and have irregular boundaries rather than the classical plane twin boundaries. These boundaries aye grooved surfaces in which the grooves themselves are parallel to a <111> direction and the sides of the grooves appear to be par-allel to (110) planes. TWINS were produced in tungsten single crystals by explosive working at room temperature. These twins differ in character from any previously reported for tungsten; however, they are similar to those found in molybdenum after compression at -196°C.1 Deformation twins "resembling Neumann bands in ingot iron" have been observed in tungsten by Bech-told and Shewmon.2 This observation was made with sintered polycrystalline tungsten pulled in tension to fracture at 100°C and using a strain rate of 2.8 x 10-4 sec-1. More recently Schadler3 found deformation twins in zone-refined tungsten single crystals pulled in tension at -196"&apos; and -253°C. These tests were conducted using a strain rate of 3.3 x l0-4 sec-1, and the twin bands were found to be parallel to a (112) plane. Deformation twins in tungsten&apos;s sister metal, molybdenum, were observed by Cahn.4 These twins were produced by compressing small (0.7 mm) vapor-deproducedposited molybdenum single crystals at -183°C. The compression was performed &apos;by impact." By the use of precession X-ray techniques, Cahn was able to identify the twin plane as {112} and the shear direction as <1ll>. Mueller and Parker1 produced deformation twins in polycrystalline electron-beam-melted molybdenum by compression at -196°C. Their "loading rate" was 5000 psi per min which, judging from their stress-strain curve, corresponds to a strain rate of approximately 0.3 x 10-4 sec-1. These twin bands were found to be parallel to (1 12) planes; however, they differed in appearance from previously observed twins. In place of straight and parallel twin boundaries they were found to be irregular, jagged, and sawtoothed. The sides of the saw teeth were identified as (110) planes and irrational planes of a (111) zone. The twins observed in the present work in tungsten single crystals are similar in appearance to those of Mueller and Parker in polycrystalline molybdenum. The starting material used in this investigation was 3/16-in. diam commercial tungsten rod produced by powder-metallurgy techniques. This material was converted to a single crystal by the electron-bombardment floating-zone technique.= The process was carried out in a vacuum of 10-5 mm of Hg using a traversing speed of 4 mm per min. Segments (=2 in. long and 3/16 in. in diam) of two crystals (A and B) produced in this manner were studied. Crystal A received one zoning pass, while crystal B received two passes. The two crystals were explosively worked at Bat-telle Memorial Institute in the following manner. A 1/2-in.-thick layer of plastic was applied to the crystals to serve as a buffer in an attempt to prevent cracking. The composite, crystal and buffer, was then wrapped with 1/8-in.-thick DuPont sheet explosive EL506A2 and detonated in water at room temperature. Metallographic samples of the worked crystals were prepared, and back-reflection Laue X-ray patterns were obtained using unfiltered molybdenum radiation. RESULTS AND DISCUSSION Blasting the crystals as described above failed to prevent cracking. The crystals fractured into several fragments about 3/16 to 1/2 in. long; however, the fragments were of sufficient size to be useful for the subsequent study. The diamond pyramid hardness of the crystals after blasting was in the range 430 to 450 as compared with 340 for the as-melted material, which shows a definite hardening resulting from plastic deformation. These hardness values were obtained using a 1000-g load and taking readings only in sound portions of the crystals free of cracks. The crystals exhibited profuse twinning as shown in Fig. 1. No such structure is present in the as-melted condition. Most of these twins have jagged twin boundaries and are similar in appearance to those found in molybdenum by Mueller and Parker. The twins in both crystals were found to be parallel to {112} planes. This identification was made by using the conventional two-trace method. Subsequent efforts to describe these twins more fully were carried out on crystal A. If the longitudinal axis of crystal A is placed in the (001)-(011)-(Il l) basic triangle of the standard cubic stereographic projection, as in Fig. 2, then the two sets of twins shown in Fig. 1 are parallel to the (112) and (121) planes. Fig. 3 shows a schematic representation of a twin with jagged boundaries. This type of twin with a <111>

Jan 1, 1962

By K. E. Brown, G. H. Fancher

An 8,000-ft experimental field well was utilized to conduct flowing pressure gradient tests under conditions of continuous, multiphase flow through 2 3/8-in. OD tubing. The well was equipped with 10 gas-lift valves and 10 Maihak electronic pressure recorders, as well as instruments to accurately measure the surface pressure, temperature, volume of injected gas and fluid production. These tests were conducted for flow rates ranging from 75 to 936 B/D at various gas-liquid ratios from 105 to 9,433 scf/bbl. An expanding-orifice gas-lift valve allowed each flow rate to be produced with a range of controlled gas-liquid ratios. From these data an accurate pressure traverse has been constructed for various flow rates and for various gas-liquid ratios. A comparison of these tests to Poettmann and Carpenter&apos;s correlation indicates that deviations occur for certain ranges of flow rates and gas-liquid ratios. Numerous curves are presented illustrating the comparison of this correlation with the field data. Poettmann and Carpenter&apos;s correlation deviates some for low flow rates and, in particular, for gas-liquid ratios in excess of 3,000 scf/bbl. These deviations me believed to be mainly due to the friction-factor correlation. However, Poettmann and Carpenter&apos;s correlation gives excellent agreement in those ranges of higher density. This was as expected and predicted by Poettmann. He pointed out that their method was not intended to be extended to those ranges of low densities whereby an extreme reversal in curvature occurs.l As a result of these experimental tests, correlations using Poettmann and Carpenter&apos;s method were established between the friction factors and mass flow rates which are applicable for all gas-liquid ratios and flow rates. Definite changing flow patterns do not allow any one correlation to be accurate for all ranges of flow. INTRODUCTION The ability to analytically predict the pressure at any point in a flow string is essential in determining optimum production string dimensions and in the design of gas-lift installations. This information is also invaluable in predicting bottom-hole pressures in flowing wells. Although this problem is not new to industry, it has by no means been solved completely for all types of flow conditions. Versluys,2 Uren, et al, 3 Gosline,4 May,5 and Moore, et al,6,7 were all early investigators of multiphase flow through vertical conduits. However, all of these investigations and proposed methods were very limited as to their range of application. Likewise, many are extremely complicated and therefore not very useful in the field. Only in the last decade have any significant methods been proposed which are generally applicable. The most widely accepted procedure in industry at the present time is a semi-empirical method developed from an energy balance, proposed by Poettmann and Carpenter8 in 1952. Their correlation is based on actual pressure measurements from field wells. Accurate predictions from this correlation are limited to high flow rates and low gas-liquid ratios. Although this method will be discussed in detail later, it should be pointed out that two important parameters, namely the gas-liquid ratio and the viscosity, were omitted in their correlation. The viscosity was justifiably omitted since their data was in the highly turbulent flow region for both phases, and most wells fall in this category. The gas-liquid ratio was incorporated to some extent in the gas-density term. In 1954, Gilbert9 presented numerous pressure gradient curves obtained from field data for various flow rates and gas-liquid ratios for the determination of optimum flow strings. However, no method is presented for predicting pressure gradients except by comparison to these curves. Baxendell, et al,10 proposed a method based on Poettmann and Carpenter&apos;s procedure

By David W. James

DURING a recent investigation of the transition from a planar to a nonplanar solid/liquid interface for the systems H20-NH4F and 0-AIR,&apos; an apparatus was developed which enabled the morphology of the ice-water interface to be examined during the transition. The slightly curved interface was viewed at a glancing angle with a Bausch and Lomb X30 stereomicro-scope. The interface was obliquely illuminated by a polarized light source. It was thus possible to differentiate between small projections or depressions at the interface, both by a shadowing effect and by the way in which they distorted the colored interference fringes across a particular crystal surface. Many attempts were made to photograph the various stages of interface breakdown. Unfortunately, the limited depth of focus of the microscope rendered the system unsuitable for photographic recording. Visual examination, however, was facilitated by continuous adjustment of the microscope focus control. The following observations of the interface transition were recorded for dilute solutions of ammonium fluoride in water. They are compared with iller&apos;s postulated morphologies shown in Fig. 1. i) The initial departure from planarity was characterized by the appearance of a large number of small depressions or "pores" in the interface. ii) The pores were arranged in wavy rows all lying roughly in the same direction within a particular grain. iii) The pores did not appear to form near to grain boundaries. iv) The pores appeared in certain grains before others. v) The transition from the pore structure to the elongated cell structure, Fig. l(d), was difficult to follow. It occurred quite rapidly and no truly irregular cell structure, Fig. l(c), was noticed. vi) The elongated cells gradually became more uniform in size and shape, with straight cell boundaries. They remained elongated, however, and no regular hexagonal cells were observed, cf. Fig. l(e). Several conclusions may be drawn from these observations. Firstly, the appearance of a poxed or, more accurately, a pore structure can be used as a criterion for the onset of constitutional supercooling. Care should, of course, be taken to distinguish between the true pore structure and artifacts caused by splashed-back liquid, particles of oxide, or inefficient decantation of liquid retained between cell boundaries, as described by Spittle et al? Secondly, and contrary to the suggestions of Tiller el l., it seems that interfacial perturbations are characterized not by curved projections but by small depressions or pores. A recent independent investigation by Biloni, Bolling, and cole5 reported in this issue indicates that the depressions might be explained in terms of dislocations intersecting the solid/liquid interface. It is possible that the dislocation concentration is reduced in the vicinity of grain boundaries. This would then explain the grain boundary depleted areas noted in (iii) above. This work was partially supported by the Air Force Office of Scientific Research, Contract No. AF 49-(638)-1029.

Jan 1, 1967

By Raymond O. Ladoo

FUSED quartz is a glass made by the fusion of nearly pure silica. Some confusion in terminology exists but in the trade today "fused quartz" generally refers to the perfectly transparent colorless product made from rock crystal whereas "fused silica" is a white, translucent product made from silica sand. Vitrified silica is the term preferred by purists for all quartz glass, but it lacks the definiteness of -the trade terms. Since the raw materials, methods of production, and properties of the finished products arc different for the two types, the trade terms are preferred. As fused quartz is amorphous, it-physical properties differ greatly from those of quartz crystal. Lacking crystallographic directions and having no piezo-electric properties, fused quartz. of course, has no value for the making of radio oscillator plates; but it does have other valuable and unique properties. Perhaps the &apos;best known and most useful properties are its extremely low coefficient of expansion and its ability to transmit short-wave ultraviolet radiant energy. Crystal quartz not only has an aver-

Jan 1, 1947

By R. H. Wightman, G. H. ADAM

In order to secure good results in the prevention of accidents, it is generally recognized that the desire for such accomplishment, as well as the aggressive and constructive action to achieve it, must emanate from the Top Management and permeate successively down through the "Chart of Authority" to the workmen. Several years ago, with the above as a basis and with full support of the Top Management, the Mining Department started a program of selling the foremen and bosses the idea that safety could be achieved and that it was desired and required. Using psychology, persistence and numerous other methods, the foremen and bosses were finally impressed with the idea that "It can be done" and "It will be done." With this in mind, new ideas were brought forth by the foremen and bosses regarding the caving operation and the specific jobs in the operation. These new ideas were taken up in round-table discussions and resulted in certain changes in the undercutting method and the actual drawing of the blocks. These changes resulted in increasing fragmentation of the blocks which prevented the usual hang-up areas in the blocks. With the rock smaller in size and within reasonable reach from the tapping drifts, accidents were prevented in the tapping section. At the same time, an enforced campaign of housekeeping throughout the mine was undertaken with very beneficial results. The foremen and bosses then, in turn, educated and trained the workers themselves to become safely conscious. In so doing, a constant re- minder was given on all jobs assigned that the job was to be done safely as well as efficiently. No man is assigned a job who is not qualified for the type of work required. Efficiency and safety go hand in hand.

Jan 1, 1949

By Harrison Schmitt

DURING the past decade the writer has studied and mapped certain ore deposits and their structural associations in the states of Chihuahua, Durango, New Mexico and Arizona, and he believes that these deposits, with the exception of the manto-chimney, are representative of the principal types in the area of the states named. In this paper the deposits are described; then generalizations are drawn so far as seems appropriate. HANOVER, NEW MEXICO The Hanover; New Mexico, zinc deposits were briefly described by Lindgren and others,1 Paige2 and recently in more detail by Schmitt.3 These, the kind ordinarily called contact metamorphic, border the southern end of an oval area of granodiorite intrusive 3/4 mile wide and 2 1/2 miles long (Fig. 1). The granodiorite has intruded, folded, and metamorphosed sedimentary and igneous rocks, which range in age from pre-Cambrian to Upper Cretaceous. About 90 per cent of the ore has replaced coarse, recrystallized, pure, fossiliferous, lower Mississippian, nonmagnesian limestone (Hanover limestone) 110 ft. thick;4 about 75 per cent of it occurs in the upper 50 ft. of this horizon just below an 18-ft. lower Pennsylvanian shale bed, which lies on a locally inconspicuous unconformity representing upper Mississippian time. The orebodies show five shapes or attitudes, each dependent on a special structural situation: 1. Most of the ore occurs as podlike; thick lenslike or other "three-dimensional" shoots extending from top to bottom of the Hanover limestone and lying adjacent to the outer contact of a silicate zone largely of andradite, which follows the intrusive contact (Figs. 1 and 2).

Jan 1, 1933

By William D. Manly, John Towers, Paul A. Beck

RECENT work on grain growth in high purity aluminum and in a solid solution type alloy of aluminum and magnesium&apos; showed that the isothermal increase of the average grain diameter D with time follows the equation [D = K(to + A)-Eq I] Here [to] is that portion of the total annealing time [t], which is available for grain growth, i.e. the annealing time less the time necessary for complete recrystallization. The parameters A and n depend only on the temperature. A has the dimension of time, and is usually of the same order of magnitude as the time for recrystallization: R. In some instances R may be substituted for A in Eq I. This is the case for example at long periods of annealing or at high temperatures, where both A and R become small in comparison with t. In such instances Eq I is simplified to [D-K-tnEq2] For high purity aluminum the exponent n increases in the ratio of about 1 to 5 in the temperature range of 350° to 600°C. 70-30 brass has been long known to exhibit grain growth of the continuous type, such as occurs in pure metals. For this reason, it was of interest to determine whether grain growth in brass also follows Eq I and 2 as it does in aluminum. Isothermal grain growth data for 70-30 brass were published in recent years by R. S. French2 and by H. L. Walker3 Fig I shows a log D vs. log t plot of French&apos;s data, together with the 500, 600 and 100°C data by Walker for 42.8 pct reduction by rolling. In such a log D vs. log t plot Eq 2 corresponds to a straight line with a slope of n. As seen in Fig I, the data of French and the 600°C data of Walker can be represented by straight lines. However, the 500 and 700°C data of Walker give curved lines and the average slope of his 500°C line is very different from the slope of the line representing French&apos;s data for the same temperature. Furthermore the curvature of the 700°C line suggests a tendency for grain growth to stop after 8 hr. If confirmed, this would constitute a definite deviation from Eq 2, not explainable on the basis of the specimen thickness effect found in high purity aluminum.1 Walker&apos;s specimens were 0.125 in., i.e. 3.18 mm thick, while the deviation occurs at a grain size of approximately 0.4 mm. A further point of divergence arose recently, when J. E. Burke suggested4 on the basis of Walker&apos;s data, that, instead of Eq 2, grain growth in 70-30 brass follows the equation [D-D. =K• t,Eq3] Here D, is the grain size as recrystallized at the temperature in question. Although it was possible to show5 that, for pure aluminum, for which isothermal grain growth has been carefully investigated, Eq 3 is incompatible with the experimental facts, the situation remained somewhat obscure with respect to 70-30 brass. In view of the discrepancies between the

Jan 1, 1948

By E. Sengier

At the Director&apos;s dinner of the A.I.M.E. on. April 22, Mr. Sengier of the Union Minière du Haut Katanga was a guest. Though a member of the Institute for sev-eral years this was the first occasion on which he had had opportunity to meet with it, and in response to an invitation from President DeGolyer, after expressing his pleasure at being present, he told informally of the present development of the Congo with which he has been so closely related. From his remarks the follow-ing has been prepared.-EDITOR. AS you know, the Belgian Congo, a fairly large colony compared with the territory of Belgium, is in the center of Africa. Natural waterways, railroads now built and new railroads under construc-tion, give increasing means of transportation and are helping toward development. The mining industry is by far the most important part of our colonial activity. Considering that we are all engineers, I will confine my figures to mining enterprise. First I will show you the relative importance of the mining industry com-pared with the total exports of the Belgian Congo. During 1925 there was exported 100,000 tons of cop-per, valued at about $25,000,000; 900,000 carats of diamonds, 8000 lb. of gold, 1700 tons of cassiterite, 300 .tons of cobalt, and 20 grams of radium, of a total value of about $35,000,000. Other products to a value of about $12,000,000 and consisting mainly of palm nuts, palm oil, cotton, ivory, copal, rubber, were also exported. From this you will see that mineral products account for about 72 per cent of the total exported value. Copper alone amounts to 52 per cent of the total and 72 per cent of the mineral exports. All minerals, with the exception of gold, which is mined by the government, belong practically toy two mining companies in which American and British capi-tal is interested with Belgian. These two companies (one called Forminière, interested in the diamond busi-ness, and the other called the Union Minière, interested in copper, cobalt, tin and radium) were formed twenty-five years ago. They started producing in 1911, but the war prevented normal operations, and active de-velopment could only be carried on after the Armistice.

Jan 5, 1927

By James Aston

A PROPER consideration of this subject is not confined to the technical channels of production and metallurgy. It concerns an industry, and should cover economic aspects which are of material importance in any program of development. The discussion may logically be treated under three subdivisions, as follows: (1) manufacture, (2) characteristics related to quality of material; (3) adaptability and exploitation of product. MANUFACTURE OF WROUGHT IRON The manufacture of wrought iron is the most ancient art of the ferrous metal industry. The eighty years or less of existence of processes identified with our modern "Age of Steel" is a relatively brief interval compared with the several thousand years associated with the production of wrought iron by man. From the primitive early methods of production, manufacture for many centuries followed the line of direct reduction. There were developments as experience was gained through the years; but man&apos;s needs for a strong, ductile, forgeable product were met by reducing the ore to metallic iron in a single-stage operation. Following the development several centuries ago of what has become our modern blast-furnace operation, manufacture of wrought iron was gradually transformed into a two-stage method of first producing cast iron and then refining this to the desired degree of forgeability; the forerunner in principle of today&apos;s scheme of manufacture of steel. The product retained the essential characteristics of highly refined base metal with iron-silicate slag incorporation, which were associated with the material resulting from direct reduction methods. Cort&apos;s invention of the puddling process in 1784 is a landmark in wrought-iron manufacture. It consisted essentially in adapting a coal-fired reverberatory furnace to the refining operation; thus lifting the industry out of the slough of

Jan 1, 1935

By J. T. Burwell

The crystal orientation in silicon iron that has been given a particular treatment described by Goss,l has been studied by Goss, by Bozorth2 and by Sixtus,3 but their results do not agree and are almost entirely qualitative. The following pages give a description of the orientation of the crystals in the material as determined by means of X-rays and expressed graphically in a pole figure. The treatment consists of hot-rolling the material into strip and then giving it two cycles of cold reduction followed by recrystallization. This produces remarkably good properties in the rolling direction, the product having a maximum permeability in this direction of more than 25,000 and a permeability at 16,000 Gauss of more than 2200. It is now generally agreed that Goss&apos;s original conclusion1 that the crystals in the final product are randomly oriented was incorrect, since Bozorth2 and Sixtus,3 using different methods, have shown that there is a decided preference in orientation. Those writers, however, expressed their results only in terms of one or more ideal orientations with deviations therefrom. X-ray Data A strip of the material containing 3.1 per cent Si, prepared by Goss,† 1.2 by 0.0125 in., was etched rapidly in warm dilute hydrochloric acid until it was 0.005 in. thick, in order to eliminate the effect of the two surface layers. The specimen was then mounted in an integrating camera similar to one described in the literature.4 The purpose of this camera is to translate the specimen during exposure, so that a statistically large number of grains contribute to the pattern photographed. The camera also allows the plane of the specimen to make various angles with the X-ray beam. An area 5 by 1.2 in. was scanned by a beam of unfiltered radiation from a molybdenum target tube operating at 37 kv., and the measurements were made principally on the peak of the white radiation. X-ray photographs were taken at intervals of 15" in a plane

Jan 1, 1940