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This investigation was supported by a grant from the American Iron and Steel Institute and a fellowship given by the Armco Steel Corp. We are indebted to J. F. Butler of the Jones & Laughlin Steel Corp. for a portion of the alloys used in this investigation and to R. L. LeRoy of the Armco Steel Corp. for chemical analyses.

Jan 1, 1962

By G. E. Steudel

THE study of the possibility of effecting a lower cost in the manu-facture of pig iron reveals the importance of the ever present question of slag chemistry and volume. Factors that determine slag chemistry and volume are the impurities in the ore available, the ash-sulphur content of the coke, and a flux material necessary to promote removal of sulphur. Of these, the ores present by far the major source of impurities and what may prove to be the lowest practical slag volume with desired chemistry in one locality may be considered low or high in some other center of iron manufacture. The Chicago district is not only blessed with ores of high quality, but with excellent coke and flux materials as well. It is the intent of this paper to discuss slag problems at the South Works only, where burdens consist of Mesabi ores, Michigan stone, and coke ranging from 7 to 9 per cent ash and containing an average of 0.57 per cent sulphur. Early in the development of modern blast-furnace practice, the con-sideration of slags was secondary to the many adjustments of mechanical difficulties, such as furnace lines, stock distribution, stove design for obtaining higher blast temperatures, improved chemical segregation and size of raw materials. Furnace operators, after making these improve-ments, turned their attention to the study of other refinements in practice, of which slag chemistry appeared to be the most important. It is only within the last two decades that operators have become familiar with the various aspects of slag compositions. The industry, while rather slow in its recognition, is indebted to such investigators as Rankin,1 Wright,1 Feild,2 Royster,2 McCaffery,3 Kinney,4 Holbrook,5 and Joseph5, whose researches concerning the elimination of sulphur within the blast furnace and the effect of slag composition upon melting point, viscosity, and desulphurizing power have established criteria for the selection of slags of the requisite quality.

Jan 1, 1939

By H. M. Howe

Page 1. Introduction............................514 2. Definitions.............................517 3. Brevity of the Heating........................517 I. THE HARDENING OF THE BORE..............517 4. The Hardening of the Bore.....................517 5. The Thickness of the Hardened Layer.................517 6. Martensitization..........................518 7. The Hardening Repetitive ......................519 8. The Temperature Cycle.......................519 9. The Hardened Layer is the Merged Layer............... 521 10. The Progressiveness of Merging....................521 11. The Progressive Thickening of the Hardened Layer from Round to Round. 523 12. Merging and Hardening are Cumulative................523 13. Three Additional Causes of the Progressive Thickening of the Hardened Layer 525 14. Progressive Roughening of the Bore..................525 15. Avoidance of an Endothermic Transformation.............525 16. Asymptotic Retardation of the Thickening of the Hardened Layer.....527 17. The Troostitic Layer........................ 529 18. The Usual Lack of Martensitic Markings................529 19. The Thickness of the Hardened Layer Should Increase with the Quantity of Heat Taken up by the Walls of the Bore.................530 20. The Decrease of the Thickness of the Hardened Layer from Breech to Muzsle 531 21. Phstic Deformation as a Contributory aCause of Hardening........531 22. In What Way May Plastic Deformation Hasten Hardening?....... 535 23. Possible Need of Coarsening.....................535 24. Carburization as a Cause of Hardening..........:.....536 25. Does Hardening Increase Erosion?..................-538 11. THE CRACKING OF THE BORE ...............539 26. Appearance of the Bore and Cracks in Elevation............539 27. The Cracks in Elevation in the Rear Ring...............539 28. The Cracks in Elevation in the Forward Ring.............540 29. The Copper Network in the Grooves.................540 30. The Cracking of the Lands......................541

Jan 1, 1918

By Ernest M. Spokes

For bituminous and lignite coals the economic picture continued to improve as it has each year since the low of 1961, with production at 480 mil- lion tons in 1964 compared with 1963's 459 million tons. The anthracite industry produced 16.3 million tons in 1964 and 18.3 million tons in 1963. The industry is looking toward a further expansion; among the new developments will be a mining wheel producing 3 million tons of lignite per year in South Dakota. It is expected that electric power generation will continue to provide the market for most of the increase in consumption, with exports second in importance in the expansion. Improvements in methods of mining and transporting coal underground and in strip mines, and the cooperation of carriers in finding ways to reduce transportation costs to distant markets, have made possible these expansions. Research continues to reduce costs of mining, transportation, steam generation of electric power and production of steam for space heating and manufacturing processes, to retain some markets and expand others. Other research seeks to expand markets by developing fuel from coal which will be more attractive than competing fuels, by reducing sulfur and other sources of air pollution. Public relations efforts of the industry are bearing fruit in a greater acceptance of coal as a modern fuel.

Jan 2, 1965

By W. L. Saunders

(Wilkes-Barre Meeting, June, 1911.) I. INTRODUCTION. IT is now generally admitted by experts that at least so far as rapid progress is concerned the Alpine system of tunnel-driving is superior to any other. This is perhaps natural in view of the record of experience in driving tunnels through the Alps. These great mountain-chains cannot be treated in the ordinary way by shaft-sinking and driving headings, thus multiplying the points of attack. The work must be done from the ends only, hence speed in driving is of the utmost importance; and, as necessity is the mother of invention, the concentration of effort to make progress has resulted in an organization and in mechanical appliances that have produced results so much in excess of the usual practice, even in America, that a discussion of the subject in detail should be of much value to the engineer and contractor. The first Alpine tunnel was the Mont Cenis, length 7.5 miles, driven with a progress that averaged about 7.75 ft. per day. Next came the Saint Gothard, 9.5 miles long, 18 ft. per day; Arlberg, 6.5 miles long, 27.25 ft. per day; Simplon, 12.25 miles long, 36 ft. per day. The figures represent progress when driving from two headings, so that by dividing them in two we get the daily single-heading progress. The latest of the Alpine tunnels is the Loetschberg, now being driven. In this work the world's record has been beaten by a single day's record in one heading of 36 ft. and by an average daily record in. one heading of 29.5 feet. The Alpine range forms a natural barrier between a large section of northern and southern Europe. This range extends from the southeast of France to the frontier of Hungary, between Italy and the plains of southern Germany. The contour

Jul 1, 1911

By W. A. Tiller, W. C. Johnston

The solute distribution ahead of an advancing solid-liquid interface is controlled by varying the momentum boundary layer thickness in the liquid adjacent to the interface. Single pass zone-melting experiments on Pb-Sn alloys are described in which the liquid is caused to rotate in the plane of the solid-liquid interface due to the influence of a magnetic .field rotating in this plane. The variation of the diffusion boundary layer thickness with field strength is determined. DURING the freezing of an alloy a partitioning of solute occurs at the solid-liquid interface, the magnitude depending upon the difference in the solid and liquid solubilities at the interface temperature. Because the diffusion coefficient is so small in the liquid relative to normal freezing rates, either a pileup or a depletion of solute occurs at the interface when the partition coefficient, kO, is either less than or greater than unity, respectively. This solute distribution is completely characterized by i) the solute concentration in the liquid far from the interface, C) the ratio of freezing velocityf, to diffusion coefficient, D, iii) the partition coefficient, ko, and iv) the thickness of the diffusion boundary layer, 6,, at the interface (this assumes that an electric field is not applied across the interface). For a particular system, C ko and D are fixed so that the character of the solute distribution can be changed only by a variation of either f or 6c. As is well known, the freezing velocity can be changed by varying the thermal environment of the alloy. Whereas, the thickness of the solute rich layer can be changed by varying the fluid flow conditions in the liquid. It is the purpose of this paper to describe a technique for controlling the fluid flow conditions in the liquid. During most solidification experiments the driving force for fluid flow arises from either mechanical mixing, thermal convection or electromagnetic mixing. The momentum boundary layer thickness, 6m at the solid-liquid interface, within which negligible movement of the liquid occurs, has been calculated for the special case of mechanical mixing where crystals are solidified by the Czochralski technique.l,2 The calculation of 6m for the case of thermal convection has also been made.3 In some calculations it has been assumed that the momentum boundary layer thickness, 6,, may be equated to the thickness of the diffusion boundary layer 6c, at the interface. However, as may be seen from Appendix I this is only true in very special cases and in general where a is a constant of magnitude determined by the particular liquid alloy. Neither calculations nor experimental data exist for the dependence of upon electromagnetic mixing. In this paper experiments are described in which the liquid is caused to rotate in the plane of the interface due to the torque developed on it by a magnetic field, H, rotating in this plane. The variation of is controlled by the variation of H. A magnetic field rotating in a plane perpendicular to the interface has been used for the purification of aluminum. Experimentally, we determined the variation of 5C with H by using the zone-melting technique of pfann5and a theoretical relationship of Burton et a1.2 pfann5 has shown that, after the passage of one molten zone through a long cylindrical charge of uniform concentration, CO, the solute distribution, C,, in the solid is as shown in Fig. 1. The equation describing this distribution is

Jan 1, 1962

By Frank C. Green

Drilling for oil and gas in Missouri in 1935 was mostly confined to proven areas, but was marked by the completion of one of the largest oil wells, 53 bbl., and one of the largest gas wells, 2,000,000 cu. ft., drilled in recent years. A new oil pool, discovered in southern Cass County late in 1934, was further developed; a new pool in southern Platte County is possibly indicated by the completion of a single small well, which flowed naturally; and a deeper sand was developed in the Marota gas pool in Jackson County. Completions dropped to a lower level than in any recent year. A total of 73 wells, which included the deepening of 8 old wells, was drilled. In Bates County, there was one gas well with an open flow of 100,000 cu. ft., and one dry hole. Cass County had six oil wells with about 100 bbl. initial production; one gas well with an open flow of 500,000 cu. ft., and three dry holes. In Jackson County there were seven oil wells with 25 bbl. initial production; 24 gas wells with 7,358,968 cu. ft. open flow, and 27 dry holes. Platte County had one oil well, one small gas well and one dry hole. The oil well flowed naturally about 4 or 5 bbl. per day. It is rather difficult to obtain production figures on either oil or gas leases, but in cases where the figures have been given to the writer in confidence, they disclose conditions comparable with many other regions. One oil lease of 32 acres has produced 125,000 bbl. in four years, or nearly 4000 bbl. per acre. Another lease has made 50,000 bbl., or about 3000 bbl. per acre. It is probable that the total daily production at the end of 1935 was close to 200 hill. per day. A gas pool covering less than one square mile has made 110,111,000 cu. ft. in about 18 months. In this period, the open-flow capacity has been reduced from about 10,500,000 cu. ft. per day to about 3,500,000.

Jan 1, 1936

By Frank C. Green

Drilling for oil and gas in Missouri in 1935 was mostly confined to proven areas, but was marked by the completion of one of the largest oil wells, 53 bbl., and one of the largest gas wells, 2,000,000 cu. ft., drilled in recent years. A new oil pool, discovered in southern Cass County late in 1934, was further developed; a new pool in southern Platte County is possibly indicated by the completion of a single small well, which flowed naturally; and a deeper sand was developed in the Marota gas pool in Jackson County. Completions dropped to a lower level than in any recent year. A total of 73 wells, which included the deepening of 8 old wells, was drilled. In Bates County, there was one gas well with an open flow of 100,000 cu. ft., and one dry hole. Cass County had six oil wells with about 100 bbl. initial production; one gas well with an open flow of 500,000 cu. ft., and three dry holes. In Jackson County there were seven oil wells with 25 bbl. initial production; 24 gas wells with 7,358,968 cu. ft. open flow, and 27 dry holes. Platte County had one oil well, one small gas well and one dry hole. The oil well flowed naturally about 4 or 5 bbl. per day. It is rather difficult to obtain production figures on either oil or gas leases, but in cases where the figures have been given to the writer in confidence, they disclose conditions comparable with many other regions. One oil lease of 32 acres has produced 125,000 bbl. in four years, or nearly 4000 bbl. per acre. Another lease has made 50,000 bbl., or about 3000 bbl. per acre. It is probable that the total daily production at the end of 1935 was close to 200 hill. per day. A gas pool covering less than one square mile has made 110,111,000 cu. ft. in about 18 months. In this period, the open-flow capacity has been reduced from about 10,500,000 cu. ft. per day to about 3,500,000.

Jan 1, 1936

By Andrews Allen

WE all remember when, a few years ago the preparation of coal was nothing but a matter of having somebody at the face or somebody in the railroad car pick out the impurities; also the sizes were generally' made" over a bar screen. Anything that was black was coal; and the only matecia1 picked out was the slate or rock-impurities that could be distinguished by eye or by hefting. This was all right as long. & coal could be sold at. a good price. After all, we are all in business to -make the most money honestly out of a certain acreage of coal and a certain plant. For this purpose what is required is the greatest possible recovery of marketable coal and the highest market price.

Jan 1, 1929

AARONS, J. BOYD, Major. AGNEW, FRANK VANS. ALLEN, HERMAN H., Private, D Co., 8th Reserve Engineers. BANKS, H. R., Lieutenant, Canadian Engineers, B. E. F. BARBOUR, PERCY E., Deputy Supt. (Captain), New York State Troopers; Captain, 22d Regiment, N. Y. N. G. BARLING, H. B., 1st Lieutenant, Engineer Officers' Reserve Corps. BIGELOW, BRAXTON. BLOOMFIELD, E. C., Lieutenant. BORROW, F. K. BROOKS, ALFRED H., Captain, Engineer Officers' Reserve Corps. BROWNE, DE Courser, 1st Lieutenant, Ordnance Dept., Fortress Monroe, Va.

Jan 8, 1917

By J. R. Sturgul, J. C. Wynn

Computers and computer applications in geophysics are fairly recent innovations. The area of data handling is one that has found many immediate applications. Initially, the use of computers involved in almost all cases, a batch-input arrangement requiring a trip to the local computer center, a wait and another trip. Even though the computer worked at incredible speeds, the time-delays, in case an error in the input data developed, often could be several days. Use of computers in mining exploration by medium-sized or small-sized companies and contractors has been almost non-existent beyond simple data reduction work. The principle J. R. Sturgul, SME member, and J. C. Wynn, both affiliated with the Dept. of Geosciences, University of Arizona, Tucson, presented this paper at the Eleventh International Symposium on Computer Applications in the Minerals Industry, reasons appear to be the time factor and the inconvenience of the frequent trips involved. With the advent of time sharing systems, whereby a company need only have access to a terminal, the main objections can be overcome. An Apparent Solution An apparent solution to the time and distance inconveniences which would permit more extensive use of computers in geophysical exploration, is to buy or lease/purchase a medium-sized computer and install it in or near one's office. This is a formidable proposition in terms of cost and programming time on both respects, but several mining companies of larger size have already gone this route. In most cases, the computers have been expensive devices with a limited memory or core size. For routine data handling this memory size is not restrictive; however, for many geophysical applications such as three-dimensional modeling this can be critical.

Jan 10, 1973

By J. H. Kittel

THE properties of the metal molybdenum have been the subject of recent investigations1,2 = which have included studies of the changes that occur in the metal when it is annealed after having been cold worked. Most of the data which have been reported have pertained to only one aspect of annealing, that is, the conditions under which recrys-tallization has been observecl. The process of recovery which may precede recrystallization docs not appear to have been investigated, and it is the purpose of this note to report observations on the recovery process in cold-worked molybdenum as determined by changes ill the thermoelectric power which occur as the metal is annealed. The measurements were made on commercially pure molybdenum wires which, after annealing at 1035°C in dried hydrogen for 1 hr, were swaged to give a series of reductions up to a maximum of 84.5 pct. The variously cold-worked wires were then annea1c.d in dried hydrogen for periods of 16 hr at progrc:ssively highel. temperatures from 200" to 1000 c with a final annealing treatment of 70 hr at. 1100°C. After each annealing treatment the ther.ma1 emf's were determined against a length of original unwo~,ked material that had received the initial hydrogen anrit,aling treatment. The difference in temperature between the hot and cold junctions was maintained at about 75'C. and. the thermal emf's were measured with a potentiometer that could be read. to 0.01 microvolt. Fig. 1 shows the thermoelectric power. (dE/dT) in microvolts per C between annclalcd and cold-worked molybdenum as a function of the degree of cold work. The effect of annealing is shown in Fig. 2. The general shape of the curves in both figures is similar to results which have been obtained for copper." It was observed that after annealing at temperatures as low as 200°C recovery was well under way. The rapid changes irt thermoelectric power observed near 900 C are probably associated with recrystallization, since such a relation has been observed with copper. Beyond 900°C the thermal emf's changed in polarity. indicating that from this point or1 the specimens were more highly annealed than the standard. Annealing treatments could not be given at temperatures higher than 1100°C due to limitations of the furnace, and it is evident that, since equilibrium values of thermoelectric powers were far from having been attained, temperatures considerably higher are required to fully anneal molybdenum. References Robert M. Parke: Molybdenum, A New High-Temperature Material. Metal Progress (1951) 60, pp. 81-96. * R. A. Long, K. C. Dike, and H. R. Bear: Some Properties of High-Purity Sintered Wrought Molybdenum Metal at Temperatures up to 2400 °F. NACA TN 2319 (March 1951): G. W. Brindley: A Thern-io-Electric Study of the Cold-Rolling and Heat-Treatment of Copper, Report of a Conference on the Strength of Solids. Physical Society, London (1948) pp. 95-106.

Jan 1, 1953

By Notman, Arthur

THIS is a day of surpluses, some good and some not so good. One can hardly pick up a newspaper, magazine, review or economic treatise without confronting the fact that we have or are threatened with more .of certain goods than we have use for, whether it be corn, wheat, cotton, coal or oil, -lumber, 'leather, newsprint, automobiles, zinc, lead, copper or what not. How did this unprecedented state of affairs arise? Who is to blame? How shall we avoid smothering ourselves in our own production? The voice of the farmer is raised in appeal to the Government to relieve him from the dilemma of his own fertility. In answer the Government employs thousands of experts and spends millions of dollars to aid the farmer. But to what end? To make him still more efficient so that he may produce even greater surpluses? Not satisfied with the result, it spends other millions to prepare vast areas of the arid land of the West for more farmers to cultivate and insure yet larger surpluses. Then what? Naturally another appeal to the Government to fix prices by financing the

Jan 1, 1928

By R. G. Davies

Isothermal annealing of quenched Fe3Al reveals that the superlattice forms by the nucleation and growth of ordered domains. The activation energy for isothermal ordering and initial domain growth is -29 keal per mole, which is thought to he the activation energy for vacancy migration. Domain growth, in the absence of excess vacancies, has an activation energy of -100 keal per mole. A maximum in the hardness is observed when the structure consists Of ordered domains, -35-4 in size, growing into a short-range ordered matrix and, also as a function of degree of order, S, with an infinite domain size at S = 0.4 to 0.5. It is proposed that both maxima are due to a transition from deformation by unit dislocations to deformation by superdislocntions. FE-AL alloys containing more than -23 at. pet Al, when quenched from above the critical temperature for the Fe3A1 type of order, always contain the maximum possible amount of FeAl (B2) type of order' (see Fig. 1). Thus when the Fe3A1 superlattice forms, in a 25 at, pet A1 alloy, it does so from an imperfect FeAl structure. The formation of the Fe3Al superlattice has been the subject of several recent X-ray,1, 2 electrical-resistivity,3"6 and dilatometric3 investigations. McQueen and Kuczynski3 concluded that the isotherma1 ordering of Fe3Al, after quenching from 800°C (T,, the critical temperature for order, is 55O°C), takes place by the nucleation and growth of ordered domains. However, Feder and Cahn4 found that the isothermal ordering was complex but more like a homogeneous nucleation process than a nucleation and growth process. Lawley and Cahn2 reported that the degree of order is a continuous function of temperature which is a characteristic of a homogeneous nucleation process. Thus, the evidence is conflicting as to the nature of the Fe3Al ordering reaction. Lipson7 was the first to suggest that ordered domains should exist in the Fe3A1 structure since, as

Jan 1, 1964

[1-Iron and Steel JOHN A. MATHEWS, Chairman RALPH H. SWEETSEH. Vice-chairman WILLIAM CAMPBELL. Vice-chairrmn MAX ROESLER, Secretary Iron Ore R C. ALLEN W. 0. HOTCHKISS MAX ROESLER ERNEST F. BURCHARD THOMAS T. READ DWIGHT E. WOODBRIDGE M. M. DUNCAN WILLIAM KELLY CARL ZAPFFE]

Jan 1, 1928

By Edwin Dudley Martin

DURING the past twelve years the iron and steel industry has made a major advance through the development of the continuous wide strip rolling mill. So far-reaching have been the results that not only has a better product been sold at a lower price but this improvement in quality has permitted manufacturers of products using steel to make important savings in the cost of fabrication. The net result has been a better product at lower cost to the consumer without reduction in either employment or of wages paid within the industry. That is why the iron and steel industry is proud of its attainment. Being a basic industry of strategic importance, such an advance in technology has had its effects on our internal economy, our standard of living, and our industrial power as a nation in both peace and wartime.

Jan 1, 1939

By Eugene S. Meieran

The effects of methods of crystal growing, wafer sawing, polishing, routine handling, diffusion, and epitaxial growth on the defects in GaAs are reviewed and studied using reflection and transmission X-ray topographic techniques. In general, it was found that boat-grown crystals exhibited fewer defects than Czochralski crystals, although all crystals showed large numbers of precipitates visible when examined in the electron microscope. Mechanical surface treatments such as sawing and mechanical polishing introduce damage to a depth of about 5 µ, most of which can be removed by suitable chemical or chem-mechanical polishing. In addition, defects can be introduced through routine handling of wafers, for example with metallic tweezers. These defects can be quite severe, and have been observed 20 µ below the wafer surface. Defects can also be introduced through diffusion and epitaxial growth. These defects, which include precipitates, growth pyramids, stacking faults, dislocations, and so forth, can be detrimental to device fabrication. It is shown that wafers or films which appear defect-free optically can contain defects visible in the X-ray topographs. WHILE the use of GaAs in the semiconductor industry has increased very rapidly in the last few years, due mainly to the recent development of many important GaAs devices,1,2 the major limit to the production of commercial quantities of many GaAs devices remains a severe lack of suitable materials technology. This lack is apparent in two critical areas. First, production quantities of high-quality GaAs crystals, reproducibly doped and precipitate-free, simply are not available commercially, although some reasonable quality material is available on a limited first-come, first-serve basis. Second, in comparison to silicon technology, little is known about the effects of processing variables on the defects either present in as-grown GaAs or introduced through processing and handling of wafers. These areas are now receiving some attention from semiconductor device manufacturers, who are studying defects in GaAs in order to better understand how either to prevent their occurrence or to cope with their existence. Most investigations of the defects in GaAs have been made by optical microscopy3-5 or transmission electron microscopy techniques.'-' Recently, however, the imaging techniques of X-ray topography, electron mi-croprobe analysis, and scanning electron microscopy are being applied to the study of GaAs.9-14 In the case of X-ray topography, a one-to-one image is obtained that must be photographically enlarged. In compensa- tion, the defects within entire wafers may be imaged by simple scanning (Lang technique15) if the wafer is reasonably perfect, or by using the scan oscillation technique developed by Schwuttke16 if the wafer is warped or distorted. The purpose of this paper is to both review and extend the general application of X-ray topographic techniques to GaAs. Emphasis will be placed on the effects of growth and process variables on the quality and perfection of both bulk and epitaxial GaAs. Reference to optical or electron microscopy results will be made when useful. Since the effects on defects of a wide variety of processing variables such as crystal growing, sawing, polishing, diffusion, and epitaxial growth will be somewhat superficially reviewed, a fairly extensive bibliography of the most important recent results in these areas is included. However, for completeness, important defects will be illustrated here, although such defects have been previously shown by others. While this paper is concerned with defects rather than with the physics of X-ray scattering, the mechanisms of contrast formation in the topographs will of necessity be briefly mentioned. EXPERIMENTAL GaAs crystals, both boat-grown18 and Czochralski-grown,'8 containing a variety of dopants of various concentrations, were purchased from outside vendors. Wafers were sliced from the crystals using a Hamco ID saw and were mechanically polished using 1 µ diamond paste. Chem-mechanical polishing was done in bromine-methanol as described by Sullivan and Kolb.18 Chemical polishing was done using a modified sulfuric-peroxide solution, 11 parts H2SO4, 1 part 30 pct H2O2, 1 part DI water.5 Zinc diffusion was carried out in a closed tube, using a 10 pct Zn-In source at 825°C for 1 hr. Oxide masking techniques were used to select the area to be diffused. Epitaxial wafers were either purchased or prepared here. All epitaxial runs prepared here were carried out using a Ga-GaAs-AsC13 source in a closed tube at a substrate temperature of 750°C. Wafers were chem-mechanically polished and gas-etched prior to deposition. The X-ray topographs were taken on a Krystallos Lang camera, operating in the transmission scanning geometry (Lang technique15) or in the reflection scanning geometry (modified Berg-Barrett technique20,21). MoKa, radiation was used for all transmission topographs using a Jarrell-Ash 100-µ spot focus. CuKal radiation was used for all reflection topographs using a General Electric CA-7 1-mm spot focus X- ray tube. Topographs were printed from an intermediate contrast inversion film, so the contrast shown in all figures here is the same as that of the original 50-µ-thick emulsion L4 Iiford nuclear plate used to record the topograph.

Jan 1, 1969

By F. A. Hill

Coal mining in the State of Washington offers many interesting problems for the mining engineer, due to the varied physical conditions occurring in different fields, and often in, the same mine. The different coal seams worked in the same mine commonly require different mining and transportation methods for economical operation. The coal measures have inclinations ranging from 5° to vertical, and in the same mine the dip of the coal may vary from 30° to 50°. In all fields, the seams are extensively faulted, folded, and sheared. The quality of the coal produced ranges from brown lignite to bituminous- coking coal, the following being typical analyses: Lignite Sub Coking Coal bituminous Moisture 23.5 14.30 0.57 Volatile hydrocarbon 31.0 33.03 23.57 Fixed carbon 37.4 41.30 65.55 Ash 8.1 11.37 10.31 100.0. 100.00 100.00 Very little of the coal contains as much as 0.75 per cent. sulphur. The brown lignites occur mostly in Lewis and Thurston Counties, and, as a rule are very cheaply mined. This coal has been successfully used in locomotives of the Oregon & Washington Railroad, after equipping them with specially designed fireboxes. The sub-bituminous coals occur in all the coal-mining counties. Their cost of production varies widely, according to the character of the formations, the pitch, and the wall conditions. This makes a fairly good steam coal, but the lump is used mostly for domestic trade, after grading into lump, nut, and pea.

Jan 4, 1918

By Alfred Wandke

The problem of vein formation has been of particular interest to the writer for years. As his work for a long time was confined largely to districts showing large deposits of copper ore, it was natural that the efficiency of replacement, as one if not the chief control of the emplacement of the ore, seemed a particularly attractive hypothesis. Of late years, in almost daily underground work in the Guanajuato district, he has collected evidence which makes it certain that in a number of cases the ore solutions were under sufficient pressure to force the rock walls apart and to hold them apart, thus offering an open space for the deposition of vein and ore-bearing material. This paper will concern itself with conditions frequently met with in hypogene ore deposits of the vein type, and will deal in particular with ore occurrence in precious-metal veins of the type classified by Lindgrenl as epithermal deposits, or metalliferous deposits formed near the surface by ascending thermal waters2 and in genetic connection with igneous rocks. To account for the emplacement of this type of ore deposit various writers have suggested the following agencies: 1. Shattering of the wall rocks. 2. Pressure of growing crystals. 3. Magmation, as treated at length by Spurr3. 4. Replacement. 5. Openings produced by folding. 6. Shearing due to gravity. 7. Shrinkage produced by the passage of pre-ore solutions. 8. Contraction joints produced by lateral secretion. To this list there may be added another agency, a discussion of which forms the basis of this paper: 9. Pressure of the ore-bearing solutions.

Jan 1, 1931

By Michel T. Halbouty

The area for which oil and gas developments in South Texas are reported for 1940 in this paper covers the same counties that were included in the reports for 1938 and 1939, with the addition of LaSalle County. LaSalle County is includcd in the Laredo district of South Texas, which totals seven counties for that district. The Corpus Christi district remains the same, with nine counties. The two districts together comprise what is known as the South Texas area for this report. Continued exploration along established trends and beyond proven field limits during 1940 provided South Texas with new fields and new producing levels at a rate of discovery fairly comparable with the high records set during recent years. The wells drilled in the counties within this district (including LaSalle) numbered 1656, approximately 8 per cent below the 1801 figure of last year. However, rank wildcats totaIed 336, an increase of 17.5 per cent compared to the 286 drilled in 1939. Therefore, since new field discoveries numbered 25 in 1940 against 29 in 1939, the rate of new field discoveries in 1940, based upon rank wildcats drilled, was I/I3.4 while that of 1939 was I/9.86, which shows a decrease of about 25 per cent in the rate of new fields. The rank wildcat tests in 1940 gave the following results: 18 produced oil, 4 produced distillate with gas, 3 produced. only gas, and 3r1 were dry holes (Table 5). Of the 1320 tests drilled in already proven fields or as extensions to pro+en areas (representing a decline of 12.8 per cent from last year's total of 1515 tests), 1048 produced oil or distillate, 60 produced gas and 212 were dry holes (Table 4). Of the producers, 50 found new sands or crude-in-distillate-sands in existing fields. Among the several fields subjected to extensive development were: Colorado, Jim Hogg County; East White Point, San Patricio and Nueces County; Rincon and Sun, Starr County; Glen, Webb and Zapata Counties; Wade City and Orange Grove, Jim Wells County; Stratton and South Clara Driscoll, Nueces County, and Aransas Pass, San Patricio and Aransas Counties. The development of important crude reserves on structures formerly considered primarily distillate fields has probably been the most important phase of the year's operations in South Texas. The Rincon, Stratton, Agua Dulce, Wade City, Odem and Robston fields provided the new crude sand discoveries. At some places crude production was opened by exploratory wells that found new sand horizons; in others by flank wells that found already discovered distillate sands sufficiently low to provide crude production. Rincon, Starr County, with its multiple sands, is now believed to be one of South Texas' largest crude-oil reserves. Offshore drilling showed important results during the year, including the discovery of two new submerged fields and the extension of the East White Point field into offshore Nueces County. The new marine fields are: East Flour Bluff) 76

Jan 1, 1941