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By Fred C. Bond

COMPRESSION TESTS THE standard method of determining the crushing resistance of rocks consists of crushing prepared shapes under slow compression, and expressing the ultimate crushing resistance at the load causing failure in pounds per square inch of crossectional area perpendicular to the crushing force, with the height approximately equal to the diameter. One-inch cubes or cylindrical drill cores are commonly used. Cubes and drill cores are cut by a high-speed steel disk with diamond dust embedded in the edges, and running under a water spray. Such a saw will cut one square inch or more of hard stone per minute. An oiled, spherical, swivel compression block of small diameter should be used to equalize the pressure. Each sample is crushed between sheets of cardboard or blotting paper extending about one-half inch beyond the edges of the stone. A cloth is wrapped around it to prevent dangerous explosive shattering. It is probably preferable to place the swivel block below the specimen, with either a rigid head or another swivel block above. Whatever the arrangement, the conditions should be selected that will develop the maximum crushing strength of the specimen, even though its top and bottom planes may not be precisely parallel. The cardboard pads may be dispensed with if the ends of the specimens are polished smooth. The use of lead pads was discontinued because of the observed tendency to split the material. The samples are weighed and measured before breaking, and the density is calculated. Cubes that contain bedding planes or veinlets are usually placed with these vertical and parallel to the crushing force, in order to develop the maximum resistance possible. A number of compression tests were made on Canadian ores, by Forrest Nagler, of the Allis-Chalmers Manufacturing Co., and are listed alphabetically in Table 1. These tests were made on one inch cubes or on diamond-drill cores approximately one inch in diameter and one inch long. The drill cores represent virgin rock, while the cubes may have been previously weakened by explosives. Compression tests have been made in the Allis-Chalmers Milwaukee Laboratory on a number of ores and other materials. These are listed alphabetically in Table 2. In test No. 1339, on limestone from the Hanna Coal Co., comparison was made between 2 by 2-in. diamond-drill core segments and one-inch cubes cut from the cores in the same strata. Results for the cylinders are tabulated directly below those for the cubes. The bedding planes were normal to the compressive force in breaking the cylinders and parallel in breaking the cubes, which accounts for the lower strength obtained from the cylinders. The percentage of net linear compression at the ultimate pressure was measured in test No. 1055 for Fontana TVA quartzite as 0.30 for cube A, and 0.37 for cube D.

Jan 1, 1946

By Fred C. Bond

The Standard method of determining the crushing resistance of rocks consists of crushing prepared shapes under slow compression, and expressing the ultimate crushing resistance at the load causing failure in pounds per square inch of cross-sectional area perpendicular to the crushing force, with the height approximately equal to the diameter. One-inch cubes or cylindrical drill cores are commonly used. Cubes and drill cores are cut by a highspeed steel disk with diamond dust embedded in the edges, and running under a water spray. such a saw will cut one square inch or more of hard stone per minute. An oiled, spherical, swivel compression block of small diameter should be used to equalize the pressure. Each sample is crushed between sheets of cardboard or blotting paper extending about one-half inch beyond the edges of the stone. A cloth is wrapped around it to prevent dangerous explosive shattering. It is probably preferable to place the swivel block below the specimen, with either a rigid head or another swivel block above. Whatever the arrangement, the conditions should be selected that will develop the maximum crushing strength of the specimen, even though its top and bottom planes may not be precisely parallel. The cardboard pads may be dispensed with if the ends of the specimens are polished smooth. The use of lead pads was discontinued because of the observed tendency to split the material. The samples are weighed and measured before breaking, and the density is calculated. Cubes that contain bedding lanes or veinlets are usually placed with these vertical and parallel to the crushing force, in order to develop the maximum resistance possible. A number of compression tests were made on Canadian ores, by Forrest Nagler, of the Allis-Chalmers Manufacturing CO., and are listed alphabetically in Table I. These tests were made on one-inch cubes or on diamond-drill cores approximately one inch in diameter and One inch long. The drill cores represent virgin rock, while the cubes may have been previously weakened by explosives. compression tests have been made in the Allis-Chalmers Milwaukee Laboratory on a number of ores and other materials. These are listed alphabetically in Table 2. In test NO. 1339, on limestone from the Hanna Coal Co., comparison was made between 2 by 2-in. diamond-drill core segments and one-inch cubes cut from the cores in the same strata. Results for the cylinders are tabulated directly below those for the cubes. The bedding planes were normal to the compressive force in breaking the cylinders and parallel in breaking the cubes, which accounts for the lower strength obtained from the cylinders. The percentage of net linear compression at the ultimate pressure was measured in test No. 1055 for Fontana TV A quartzite as 0.30 for cube A, and 0.37 for cube D.

Jan 1, 1947

By Arthur B. Yates

DIAMOND drilling has advanced and expanded during the past few years. Along with this increase there has been a marked trend to rely more and more upon drilling for the outlining of ore for reserve purposes. This is especially true underground, where men have not been available for opening up ore by crosscuts, drifts and raises. During the recent heavy call upon known ore reserves, more drilling has been done for exploration and it has become expedient to drill longer lateral holes from underground and deeper holes both from surface and from exploration headings in the mines. Furthermore, these deeper holes have to be drilled closely enough to warrant calculation of "probable" if not "proven" ore, from the results obtained therefrom. Interpretation of diamond-drill results has become more precise and reliable with the growing knowledge and understanding of the geologic structures that control the geometry of ore distribution, and this has broadened the field of usefulness of the drill. All of this has created a necessity and a demand for more accurate control of the hole as to direction, a more precise and reliable method of surveying for position, and a need for better and more complete core recovery, as well as larger cores, to provide an adequate sample. At depth the control becomes more difficult and, at the same time, more important. CONTROL A close study of drilling in various parts of the world for a period of more than 20 years has brought to light one definite rule, practically invariable; namely, that diamond-drill holes tend to deviate into a position normal to any structure existing in the rocks, such as bedding, schistosity, gneissosity, or even parting or jointing-even if the hole is started at almost any angle other than parallel with the structure. It also appears that the better developed the structure is, the more quickly will the hole get into a position perpendicular to it. It has often been said that there is a tendency for holes to "drift" in the direction of rotation. This is obviously untrue, for in a vertical hole the measure of deviation would depend upon the azimuth chosen as zero, and there is an infinite number of choices. It has been proved, however, that in homogeneous rocks there is a tendency for the hole to corkscrew, and that the direction of the spiral is the same as the direction of rotation. This may account for the belief that holes drift in that direction. Some tests have been made using right-hand and left-hand rods, and these show that no matter what the direction of rotation the hole will swing into a position perpendicular to the structure. Methods of Control The foregoing empirical rule may be used as an indirect method of control. If the prevailing structure is known, it may be advantageous to start the hole as nearly normal to it as possible, for the nearer the direction of the hole is to this ideal, the straighter it will remain. This, of course, is not always practical and in some cases is impossible. Usually such a

Jan 1, 1946

By Galen Clevenger

TELLURIUM has had the rare and unpleasant distinction of having fewer uses than any of the other common elements; indeed, it has had no regular or important uses. It is not only a useless and disagreeable element, but to the metallurgist it has been a nightmare. The interference of tellurium with the recovery of gold and silver from certain ores, as well as the difficulties it occasions in the electrolytic refining of copper, lead, and silver, are too well known to require enumeration here. In fact, the potential producers of the element have been quite willing to throw the crude products from which it might be recovered into the sewer. First isolated from a gold ore in 1782, although remaining a practically unknown element to the general public, it has long been a guiding star to the Western prospector in his quest for the "golden fleece." On the burning sands of the desert, in the frigid North, and in the mountain fastnesses of the more temperate regions of this and other continents, he has endured all manner of hardships in his search for tellurides; for where he found indications of tellurium, there he expected also to find rich deposits of gold and silver. This peculiar superstition, that tellurium, associates itself in nature with the precious metals, is not with-out reason, for witness the fabulously rich gold tellu-ride deposits of Cripple Creek and Western Australia. Selenium, the sister element of tellurium, which it resembles in many of its properties, was first isolated in 1817. It is found in small amounts in certain native sulfur deposits, and in many copper and silver ores from all parts of the world. Until a few years ago, selenium, like tellurium, was practically useless. The, unusual property of having its electrical conductivity influenced by light has long been known. Selenium cells, which for many years have been a scientific curios-ity, in the future may come to be of more commercial importance, but this use could scarcely absorb any large amount of the element.

Jan 1, 1923

By Archer E. Wheeler, Milo W. Krejci

There are two general methods in use for the production of metallic copper from matte which are worthy of consideration : (1) the Welsh blister process, and (2) the converter process.' As practically all of the copper produced to-day is made in converters, we will give a brief outline of that process before proceeding with the special subject of this paper. Matte may be roughly defined as a mixture of the sulphides of copper, iron, nickel, silver, etc. In the converter process this is blown up to metallic copper in a modified type of Bessemer converter. The conversion of matte consists mainly in, (1) the removal of sulphur in the form of SO2, and (2) the slagging of the iron. With this brief statement we come to the two subdivisions of the process of converting mattes: Converting with acid linings. Converting with basic linings. Converting with Acid Lininys, This is carried out by lining the converter with siliceous rock or ore, which performs two functions: It protects the iron shell of the converter from the molten charge, and it furnishes the silica for combining with the iron as it is oxidized from the matte, to form a ferrous silicate. It follows from the second of these functions that this siliceous lining must be replaced from time to time, and in practice it has been necessary to reline converters every 8 to 40 hr., this time varying in different plants and even with different linings in the same plant, the life of a lining depending upon the grade of the matte treated, and upon the composition, the thickness, the tamping, and the drying of the lining.

Jan 1, 1914

By Samuel Storchheim

IT was noted that variations existed in the magnetic properties, namely, coercive force, He, and rema-nence, Br, of 18/8 stainless steel wires of the same analysis when these wires were given the same percentage of reductiori of area at different rates of reduction. In order to determine the extent of these variations, a program was initiated whereby commercial 302 and 304 stainless steels were drawn with a wide variation of speeds. Ultimate tensile strengths and specific resistances, as well as the Hc-BT measurements, were determined. If variations of considerable magnitude were found, it was thought that the knowledge accrued from the investigation could probably aid in determining the particular drawing speed required to obtain desired properties for a given specification for a particular analysis of wire. Drawing Procedure Two specimens (set I, No. 302 and No. 304), the chemical analyses of which are given in Table I, were drawn at different speeds, namely, 45 to 3900 ft per min, directly from 0.016 in. diam wire to 0.004 in. diam wire, a 93.7 pct reduction of area. To obtain this high percentage of reduction, the wire at 0.016 in. was softened by annealing at 1150°C. It was then strung in a No. 16CF variable speed Vaughn drawing unit and passed through 13 B.&S. gage dies of successively smaller diameter, as shown in the accompanying table. Following this step, several hundred feet of the wire was drawn, at a particular speed, through the dies and wound upon a spool. Once the sample of wire was drawn at the desired speed, the spool with the finished sample was removed, tagged for later identification, and an empty spool was placed in the machine. Another wire sample was drawn at a different speed, after making the necessary adjustments upon the Vaughn unit. At the greater speeds, several thousand feet of sample were drawn to insure that the wire to be used for testing would be uniform. This was done because the desired speed was not reached instantly; the wire taking a short while to attain the required drawing rate. All speed measurements were made by placing a tachometer against one of the machine's pulleys during the actual drawing of the specimens. 84.4 pct reduction of area. The 0.072 in. diameter wire was also annealed at 1150°C. The process of obtaining samples was the same as described above. The only difference between the two was that the rates involved were not as extensive, set II covering a range of 625 to 1150 ft per min. Tensile tests were carried out for the 0.004 in. diam wires on a horizontal Scott Tensile Tester, while tensile tests for the 0.028 in. diam wires were made on a vertical Scott Tensile Tester. Each value listed in the tables represented the average of five samples with a maximum deviation of approximately 3 pct among the samples. Resistance per foot of the wires was determined by use of standard bridges accurate to the nearest hundreth of an ohm for the 0.004 in. wire, and to the nearest thousandth of an ohm for the 0.028 in. wire. The resistances per foot were then converted to resistivities by use of the following equation: P = RxCM where R is the resistance per ft in ohms per ft; CM, the area in circular mils; and P, the resistivity in ohms—CM. The values listed in the tables likewise

Jan 1, 1952

By Jasper L. Stuckey

It is not known when kaolin mining was first begun in North carolina, Evidence, in the form of excavations and primitive tools, indicates that some of the deposits were worked in prehistoric times. It has been suggested that the prehistoric mining was for mica, but the workings were all in altered or partly altered pegmatite material and the dumps do not represent the amount of material removed. some of the early openings may have been made in search of kaolin or semi-kaolinized feldspar which was sold to English1 traders along the coast and used in some Of the early English porcelains. In 1744,2 an application was made for an English patent to produce porcelain from an earthy mixture obtained from the Cherokee Nation in North America. It is well established, however, that the occurrence of kaolin in western North Carolina was known in England by 1767. In that year, Josiah Wedgewood sent T. Griffiths3,4 to what is now Macon County, North Carolina, to secure a supply Of kaolin for use in England. Griffiths diary, now in Etruria Museum, Stokes-on-Trent, contains a most interesting account of his experience. Kaolin was discovered at St. Austell, England, shortly after the voyage Of Griffiths, which probably accounts for the lack of further interest in American kaolin. Between 1767 and 1888, there are no records of kaolin mining in North Carolina. In the latter year, however, mining was begun near Webster, Jackson County, and, in the intervening period, has become an important industry. 'Or some 20 years, kaolin mining was carried On chiefly in Jackson, Macon, and Swain Counties. About 1904, it was begun in the Spruce Pine district and for the past 20 Yea's most of the kaolin mined in the State has come from Avery, Mitchell, and Yancey Counties. Distribution The kaolins of North Carolina are limited in occurrence to the Piedmont Plateau and Appalachian Mountain area of the State. While kaolins are widespread in the Piedmont Plateau, having been prospected for in Rutherford, Cleveland, Gaston, Granville, Lincoln, Catawba, Ire-dell, Richmond, Moore, Randolph, and Montgomery Counties, the production from that area has never been important. The known deposits of commercial importance are limited entirely to the mountain area of the State. While kaolins occur widely distributed throughout the mountain area and have been prospected for in many counties of that area, commercial production has come chiefly from two districts. One of these includes Jackson, Macon, Swain, and Haywood Counties. The other includes Avery, Mitchell, and Yancey Counties. Geology With few exceptions, all the known kaolin deposits in North Carolina contain

Jan 1, 1948

By Jasper L. Stuckey

It is not known when kaolin mining was first begun in North carolina, Evidence, in the form of excavations and primitive tools, indicates that some of the deposits were worked in prehistoric times. It has been suggested that the prehistoric mining was for mica, but the workings were all in altered or partly altered pegmatite material and the dumps do not represent the amount of material removed. some of the early openings may have been made in search of kaolin or semi-kaolinized feldspar which was sold to English1 traders along the coast and used in some Of the early English porcelains. In 1744,2 an application was made for an English patent to produce porcelain from an earthy mixture obtained from the Cherokee Nation in North America. It is well established, however, that the occurrence of kaolin in western North Carolina was known in England by 1767. In that year, Josiah Wedgewood sent T. Griffiths3,4 to what is now Macon County, North Carolina, to secure a supply Of kaolin for use in England. Griffiths diary, now in Etruria Museum, Stokes-on-Trent, contains a most interesting account of his experience. Kaolin was discovered at St. Austell, England, shortly after the voyage Of Griffiths, which probably accounts for the lack of further interest in American kaolin. Between 1767 and 1888, there are no records of kaolin mining in North Carolina. In the latter year, however, mining was begun near Webster, Jackson County, and, in the intervening period, has become an important industry. 'Or some 20 years, kaolin mining was carried On chiefly in Jackson, Macon, and Swain Counties. About 1904, it was begun in the Spruce Pine district and for the past 20 Yea's most of the kaolin mined in the State has come from Avery, Mitchell, and Yancey Counties. Distribution The kaolins of North Carolina are limited in occurrence to the Piedmont Plateau and Appalachian Mountain area of the State. While kaolins are widespread in the Piedmont Plateau, having been prospected for in Rutherford, Cleveland, Gaston, Granville, Lincoln, Catawba, Ire-dell, Richmond, Moore, Randolph, and Montgomery Counties, the production from that area has never been important. The known deposits of commercial importance are limited entirely to the mountain area of the State. While kaolins occur widely distributed throughout the mountain area and have been prospected for in many counties of that area, commercial production has come chiefly from two districts. One of these includes Jackson, Macon, Swain, and Haywood Counties. The other includes Avery, Mitchell, and Yancey Counties. Geology With few exceptions, all the known kaolin deposits in North Carolina contain

Jan 1, 1948

By D. Torrey

Considering the two great interests of to-day, in iron upon the one hand and steel upon the other, and recognizing with measurable distinctness the peculiar fitness of each for special services to which they are applied, the proposition to unite the two metals in combination, to bring into simultaneous use the peculiar advantages which each offers, has great attractions. The limited success which has been attained by trying to bring about such combinations of the two metals through the use of fluxes in welding, has led to the general adoption of the opinion that an effective union of the two metals is impracticable, or to the view that if practicable it would have but limited commercial value. Such opinions are, I think, premature and erroneous, and having gained some knowledge of the character and value of the "Wheeler process" for welding iron and steel without the use of fluxes, I submit the following observations and opinions of the matter for your information, with the hope of eliciting such a discussion of the subject as it may require. The principle of the invention is to bring the two metals simultaneously to a welding heat in one pile, and then to manipulate it.

Jan 1, 1879

By A. G. Weber, R. L. Ledbetter, A. L. Hicks

A procedure which makes use of both analog and digital computers has been developed for predicting the pressure-production behavior. of water-drive reservoirs. The electric analyzer is used for matching the past pressure and production history of the reservoir and inferring the physical characteristies of the aquifer. When the history has been matched, a .set of base curves called influence functionce" are derived and the future behavior of the reservoir is calculated from these curves. INTRODUCTION Electric analog methods are particularly well-suited for complex water-drive problems. Like all other methods of analyzing water-drive reservoirs, however, analog methods are subject to certain limitations. One of the more obvious and serious of these results from inaccurate or insufficient knowledge about physical characteristics of the reservoir and aquifer. However, it is not insurmountable because the unknown characteristics can usually be inferred from the reservoir's previous behavior. Simons and Spain have shown that even with scant reservoir data and limited production history, electric analyzer studies can provide useful and reliable results. Aside from this limitation on analyzer predictions, the main disadvantage has been lack of a technique for keeping predictions abreast of latest production forecasts. Pressure behavior of a reservoir depends on the rate at which fluid is withdrawn; it is therefore necessary to specify the future withdrawal schedule before the future pressure behavior can be calculated. Conventionally, the electric analyzer predicts pressure behavior for a specific production schedule. If this schedule is abandoned in favor of some new one, as is frequently the case, either the study must be rerun or results adjusted in some manner. The usual procedure is to predict pressures for several different forecasts covering a wide range of production rates. Pressures for specific rates other than those studied can then be approximated by interpolating between the analyzer predicted curves. However, reliability of this type of prediction is doubtful. This paper describes a technique for predicting future behavior of water-drive reservoirs that retains all advantages of electric analyzer analysis and eliminates the main disadvantage. That is, the analyzer is used conventionally to infer unknown reservoir parameters from the pressure history, but not to predict the future behavior directly. Instead, a derived set of base curves, called influence l'unctions, can be used to calculate future behavior for any production schedule.

By A. J. Teplitz, R. J. Goodwin

A new type water shut-off for use in air drilling has been developed. The method has been 99 to 100 per rent effective in several different formations of inter-ranular-type porosity. Since costs for materials, time and equipment used are relatively small, the process should extend economies of air drilling to many new areas. The treatment involves a new technique for forming a water-inroluble precipitate within the pores of a rock. Advantage it taken of the difference in mobility of a liquid and a gas in porous media to achieve the greatest volume of precipitate in a given pore. Reactants selected for the laboratory (2nd field tests were aluminum sulfate solution and gaseous ammonia. This process has been tested in both intergranular and fractured-type porosities. It has consistently shut-of between 99 and 100 per cent of the water flowing from formations having intergranular-type porosity and perrlreuhilities ranging from a few millidarcise to over a darcy The treatment is not particularly suitable for shutting-off water from fractured formations although plugging of the order of 50 per cent or greater has been achieved in all such applications. Among advantages of the treatment are: (I) no reaction waiting rime after a relatively short placement time, (2) a low mate-rials cost of about $3/f1 of hole treated, (3) use of common service-type equipment for treatment, and (4) no unusual requirements for mixing and placement. INTRODUCTION In rotary drilling with air or gas it has been possible to increase bit life by tenfold and more than double rate of penetration over corresponding performance when drilling with mud. These factors have amounted to as much as 22 per cent savings on total cost of drilling a well. However, these advantages are rapidly lost when water is encountered in an air- or gas-drilled well because water interferes with the removal of cuttings from the hole and also gives rise to other difficulties. In attempting to combat water troubles, operators have commonly resorted to such measures as mist drilling, treatment with cement or chemicals, converting to conventional mud drilling, or setting casing. In many cases these measures have either been costly or ineffective. In an effort to overcome this problem, studies were undertaken to develop an effective and economical water shut-off technique for use in formations possessing inter-granular-type porosity. Extensive laboratory experimentation finally led to a unique method for producing a water-insoluble precipitate within the pores of a sandstone. The unique part of the treatment is use of a liquid and a gas to form the precipitate, and in this case the reactants used were aluminum sulfate solution and gaseous ammonia. The reaction between these two materials is shown in the following equation. Al2 (SO1)3 - 18 H20 6NH2? saturated Water- Solution Cat 2A1(OH)3 . n H20 3(NH4)2SO • n H20 Solid Solid That is, a solid precipitate consisting of aluminum hydroxide and ammonium sulfate is formed when ammonia reacts with aqueous aluminum sulfate. The aluminum hydroxide is insoluble in water and the ammonium sulfate, though soluble, can only be removed from the formation pores by diffusion—an extremely slow process. Although the precipitate formed by the reaction is not particularly firm, great strength is not needed for a precipitate to bridge and plug intergran-ular-type porosity. A flow path in such a system is extremely tortuous and involves a great variety of pore

By Robert E. Green, T. Hinton

The velocities of the three possible modes of elastic-wave Propagation have been calculated for single-crystal aluminum at 1-deg intervals throughout the standard steveographic triangle. The results are presented as isospeed contours. The deviations between the direction of maximum energy propagation and specirzen axes are presented as arrows drawn within the standard triangle. The orientation factors associated with dislocation nzotion on the primary slip system only and also on all twelve slip systenzs have been calculated for all three elastic waves. The orientation factors associated with a longitudinal standing--7aue resonant specivnen hazle also been calculated. The relevance of these results to ultrasonic attenuation measurements is discussed. DUE to the widespread use of ultrasonics in the investigation of the properties of solids a number of authors15 have discussed in detail the theory of elastic-wave propagation in solids. In this paper the modes of wave propagation are evaluated according to the procedure suggested by reeen' for the case of single-crystal aluminum at 1-deg intervals throughout the standard stereographic triangle. The wave speeds are presented in the form of contour diagrams within the standard triangle. The deviations between the direction of maximum energy propagation and the normals to the wave fronts are presented as arrows drawn within the standard triangle. The orientation-de pendent factors (orientation factors) associated with dislocation damping as derived in the preceding paper6 have been calculated for the case of aluminum at 1-deg intervals throughout the standard triangle. The orientation factors for dislocation motion on the primary slip system only and on all twelve slip systems are presented in the form of contour diagrams, for both the traveling- and the standing-wave conditions. The relevance of these results to ultrasonic attenuation measurements is discussed. ELASTIC-WAVE PROPAGATION Three waves can be propagated in a linear elastic homogeneous anisotropic medium. The velocity of propagation v of each of these waves in a medium of density p can be obtained from the determination of the eigenvalues and eigenvectors of the matrix equa- The A's are a series of moduli which are functions of the elastic constants cij and the direction cosines 1, m, and n of the specimen axis. In the case of cubic single crystals where there are only three nonzero elastic constants cll, c12, and C, the A's are, The solution of Eq. [I] will give the wave speeds (eigenvalues) and the direction cosines a, 0, and y of the particle displacements (eigenvectors). To obtain the direction of maximum energy flux requires the calculation of the energy-flux vector ET with com- w is the angular frequency, A, the amplitude, and v the velocity of the wave. The direction cosines a, b, and c of the energy flux vector are then given by

Jan 1, 1967

By M. M. Fidlar, Ralph E. Esarey

A marked decrease in drilling during 1937 in Indiana seemed to have no undesirable effect upon the oil and gas industry. Instead, production figures for oil showed a small increase over those for the preceding year, although not so much gas was marketed as in 1936. Drilling activity was centered in proven areas, and the proportion of dry holes to the number of wells drilled decreased somewhat. During 1937, including old wells drilled to deeper horizons, 134 wells were completed in Indiana, of which 39 were oil wells, 39 gas wells, and 56 dry holes. Nearly 75 per cent of the holes were drilled in proven areas. Of the 36 wells drilled in wildcat areas, only four found commercial production. Wildcat wells were especially numerous in Vigo, Pike, Perry and Spencer Counties. Exploratory drilling activity in Vigo County resulted in part from the drilling of the discovery well in the new Prairie Creek field. In Pike County, wildcat wells were drilled in the search for new supplies of gas to meet the demand in the southwestern portion of Indiana. Drilling in both proven and wildcat areas in Perry and Spencer Counties continued to be heavy, because of the presence of shallow Missis-sippian sands and the resulting low cost of drilling and equipping. At the end of the year, 42 of the wells started in 1937 were not completed. Only a few locations were drilled in the old Trenton field, but the wells, many of them 40 years old, continued to furnish a small supply of gas for domestic consumption. Oil production in the Jay County portion of the Trenton area was nearly twice that of 1936, owing in part to a vacuum system installed on several leases. The Harrison County (Laconia) gas field is being developed northward to offset water encroaching from the south. This water in the black shale threatens to put an end to the steady production that this field has furnished for many years. During 1937, the Oaktown gas field again furnished more gas than any other field, but production in that area showed a marked decrease over the marketed gas for 1936. During the early months of the year, seven wells were completed in the Oaktown field to bring the total number of producing wells to over 40. At present, all the operators in the area are

Jan 1, 1938

By Hugh Spence

THE use of natural feldspathic rocks, as opposed to straight feldspar, for ceramic purposes is not new. "Cornwall stone," a semi-kaolinized granite containing fluorite, has long been used by the English pottery trade instead of feldspar, and "Carolina stone," a similar rock, is now being offered to the American trade. A recent report of the U. S. Bureau of Mines states that trachyte, a glassy volcanic rock, is being used in California instead of feldspar in ceramic bodies. In Germany, phonolite and basalt have been investigated, and possibly also used, as ceramic raw materials, and extensive research has been conducted in Russia in recent years looking to the utilization of the immense bodies of nepheline syenite of the Kola Peninsula, which is the host rock of the apatite deposits now being exploited on a large scale in the Murmansk region; the nepheline is recovered as a by-product of the concentration of the apatite. Long used principally as a raw material for the pottery and allied industries, where, in bodies, glazes, enamels, etc., it serves as a fluxing ingredient and forms, on firing, a glassy bond with the more refractory clay, flint and coloring particles, feldspar has been finding ever increasing employment in glass. In 1936, over half of the nearly quarter of a million tons of feldspar sold in the United States went to the glass trade. Its usefulness for this purpose is due to the resistance to thermal shock which it imparts to glass products, particularly bottles, containers and tableware, because of its alumina content, which averages from 16 to 20 per cent. Active search has been made on the American continent during the past few years for other minerals of feldspathoid type, with comparable or higher alumina content, that may be suitable for glass and other ceramic purposes. One of the most important results of this work has been the delimiting in central Ontario of large bodies of nepheline syenite of excellent ceramic grade.

Jan 1, 1938

By K. V. S. Sastry, V. P. Mehrotra

A laboratory investigation was carried out to study the influence of asphalt, bentonite, and corn starch binders on the pelletization kinetics of coal fines and on the quality of the resulting pellets. Pellet quality was evaluated in term of the compression strength, impact resistance (drop test), abrasion resistance, and resistance to severe weather conditions. The amount of binder addition did not significantly influence the pellet growth kinetics. However, the pellet quality varied markedly depending upon the type and the amount of binder wed. Experimental results are explained on the basis of the mechanism of interaction between the coal particles and the binders. Of the three binders tested, corn starch proved to be the best in all respects but for the resistance to water penetration. Finally, a combination of corn starch (imparting strength) and asphalt emulsion (imparting resistance to water penetration) was found to yield the best quality coal pellets.

Jan 1, 1983

By D. O. Ehrenburg, R. J. Watson

During the earlier period of electrical prospecting, the search for orebodies was by far the most important application of this method of geophysical prospecting. In the past few years, however, increasing attention has been paid to the possibilities of this method in the investigation of subsurface structures. Not only have fault zones been located, but attempts have been made to determine the depth to certain strata and thus contouring on some bed which proves to be a good "electrical marker." Many workers have published the results of field tests showing how their particular interpretations have agreed with the actual field conditions, but very few have stated their method of interpretation. Weaver, Hummel and Stefanesco and Schlumbergerl have given a more theoretical discussion of the resistivity methods. Hummel and Stefan-esco and Schlumberger have published mathematical solutions for the flow of electricity in a medium involving four layers. In this paper the authors present a solution for the flow of electricity in a medium of any number of horizontal strata. By means of this solution, curves showing the relationship between the apparent resistivity and the electrode spacing can be computed for ideal cases. Point-source in an Infinite Homogeneous Medium In resistivity measurements the current is conveyed to the earth by means of two electrodes, which can be mathematically treated as point-sources of equal and opposite strength. A point-source of strength I is defined as a point at which electricity is being generated at the constant rate of I coulombs per second, or I

Jan 1, 1932

INTRODUCTION The International Finance Corporation (IFC) is affiliated with the International Bank for Reconstruction and Development (World Bank) but operates with a separate staff and funding. It supplements the activities of the Bank by providing, to private business, equity and loans without government guarantees in whatever form and combination most suited to the project. IFC frequently complements the Bank's activities by utilizing, for example, the Bank's public sector infrastructure activities to support IFC's private sector projects. In the case of local financial institutions especially, IFC collaborates with the Bank by providing technical and financial assistance. IFC is the world's largest multilateral organization which finances private sector business in developing countries. IFC's fundamental purpose is to promote the economic development of its developing member countries through the support of the private sector. Of the 124 member countries of IFC, more than 100 are developing countries. Since it began operations in 1956, IFC has been associated with more than 2,000 companies and financial institutions in supporting over 700 business ventures in more than 80 countries. The total capital costs of these projects exceeds $26,000 million. In the 1984 fiscal year, IFC approved 62 projects in 37 countries with a total project cost of $2,473 million. IFC will make investments only if sufficient capital cannot be obtained on reasonable terms from other sources. IFC often serves as the catalyst for a project by encouraging other investors--from inside and outside the host country--to make their own equity investments along with the local sponsor for a particular project. IFC'S SPECIAL ROLE The significance of IFC's role extends beyond just its financing and technical assistance: IFC's capability to raise investor confidence in a project and to help all the participants to arrive at mutually satisfactory investment arrangements is its distinctive character. Direct Investments IFC invests in all types of projects both large and small. Heavy industrial ventures not only supply essential materials and equipment for other domestic enterprises, but also earn foreign exchange through exports. In recent years, increased emphasis has been placed on agriculture and agribusiness products, aquaculture, food and food processing, and other renewable and nonrenewable resources such as metals and energy. [ ] An overall objective of IFC is to assist entrepreneurs and others in the private sector raise the needed capital for business ventures. IFC does not compete with, nor seek to replace private initiative and capital. Rather, IFC helps to raise funds in order to undertake projects that would otherwise be held back by the lack of adequate funding. IFC can do this in several ways: IFC can invest in equity and make loans for its own account. But beyond that, IFC can reach out into the international capital markets in search of additional capital. Because of IFC's 25 years experience and record, outside investors who might otherwise be

Jan 1, 1985

By N. E. Brown, F. L. Versnyder

THE apparent dependency of the electrical characteristics of hexagonal crystalline selenium on microstructure has aroused much interest in microscopical studies of selenium. Microscopic observations on the crystallization of selenium have been made by Escoffery and Halperin,' P. H. Keck,' and other investigators. It is the purpose of this paper to discuss the microstructural changes observed on polished cross-sections of single layers of selenium after various heat treatments. Observations were also made on crystallization of the free-surface layer of these deposits. In general, all of the transformations studied were either transformations of the vitreous selenium to hexagonal selenium or micro-structural transformation of the hexagonal selenium itself. Procedure The selenium used in this work was obtained from the American Smelting and Refining Co. and was approximately 99.96 pct pure. An intentional impurity of 1 part per 2,000 of bromine was added to the material prior to evaporation. A thickness of approximately 0.002 in. of this selenium was vapor deposited on an aluminum base plate. The maximum plate temperature during the vacuum vapor deposition was 140°C. Mounting of the cross-sectional specimens for metallographic study could not be done in plastic mounting media, as is customary, since temperatures in excess of 50°C would cause unwanted transformations. Consequently, a simple clamp-type device was used to mount the specimens for preparation. All grinding operations were then done carefully by hand in order that the specimen not become heated during this operation. Wet polishing was done on the conventional metallographic polishing laps, using successively finer grinding powders. An extremely careful polish is necessary, since observation and micrography of the specimens are done in the unetched condition under polarized light. The two observations of crystallization made on the free surface of vitreous selenium deposits (Figs. 4 and 5) were made on surfaces which were perpendicular to the cross-sections studied. These free-surface layers were examined directly, i.e., no pre- vious metallographic preparation, as obtained from the vacuum vapor deposition. Microscopic Observations A study was made of polished cross-sections of the vitreous selenium as-deposited. It was noted that in all cases there was columnar crystallization adjacent to the base plate, which appeared to occur during the vacuum deposition process. This observation has also been made by Keck? It also was observed that vagrant spherulitic crystallization occurred in the vitreous selenium. The term "vagrant" is used, since these spherulitic grains appear to crystallize at random throughout the vitreous selenium during the vacuum deposition process. Columnar crystallization at the A1-Se interface and a typical spherulite observed in a polished cross-section of "as-deposited" vitreous selenium may be seen in Fig. 1. Cross-sectional samples of vitreous selenium studied after heat treating individual samples for 20 min in 10" steps from 80" to 220°C revealed that crystallization—in this case, columnar crystal growth —proceeds from the aluminum base plate to the surface of the specimen (Fig. 2). Crystallization was microscopically observed to be complete after the 130°C heat treatment. Visual examination of the free surface of the specimen after the 130 °C heat treatment revealed the readily recognizable grey appearance of the completely crystallized selenium, in corroboration of the microstructural observations. No microstructural transformations then appeared to take place between 130" and 190°C. At 190°C the beginning of recrystallization appeared and proceeded until the columnar grain structure had been completely transformed to equiaxed grains between 210" and 220°C (Fig. 3). Naturally, the grain size of the recrystallized grains at the lower temperatures (190" to 210°C) was smaller than is illustrated in Fig. 3. In addition, polished cross-sections of deposits heat treated at 140°C for 10 min to cause complete crystallization and, subsequently, heat treated in 10" steps from 80" to 220°C for 20 min were studied. As expected, no microstructural transformations took place until the beginning of recrystallization was observed at 190°C. A comparison with the previously studied specimens revealed that recrystallization proceeded almost identically in the two experiments although in the first case the deposits were vitreous prior to the series of heat treatments and in the second case they had been crystallized by a previous heat treatment. By heat treating for longer times (180 min) at lower temperatures, the

Jan 1, 1956

By D. J. Carney, E. Van Meter, J. J. Oravec

A study was made of combustion-air temperatures and factors affecting air temperatures in the open-hearth regenerative systems. Air-temperature surveys in the regenerative system revealed marked thermal gradients in the air above the checkers. The design of the fantail-uptake region plays a prominent part in increasing the heat recovery of the regenerative system. THE efficiency of the open-hearth regenerative system is one of the most important factors affecting open-hearth performance. Until recently, this factor has not received the attention in the literature given to many other items affecting performance, such as the type of charge, speed of charging, and the mechanical equipment of the open hearth. J. S. Marsh' emphasized the importance of the flame temperature and its dependence upon the combustion-air temperature. By means of measured air temperatures in open-hearth furnaces, data were presented which showed a remarkable degree of correlation between production rate and combustion-air temperature. This correlation was extremely good in view of the numerous factors, other than air temperature, which affect open-hearth production rates. In Marsh's work, a 100°F increase in air temperature reduced the heat time by approximately 45 min. Realizing the importance of combustion-air temperature, it is desirable to know which factors control the regenerative efficiency of the open-hearth furnace. B. M. Larsen recently discussed this subject.' The present paper illustrates a few of the more important items that affect regenerative efficiency and combustion-air temperature. In the latter part of 1951, a study of open-hearth combustion-air temperatures was begun at the South Works of the United States Steel Corp. In the initial work at open-hearth shop X, which produces low carbon steel products, temperatures were measured in the uptake in a manner similar to that used by Marsh' and the results obtained were very similar to the Bethlehem data. When it was decided to expand the study of combustion-air temperatures, open-hearth shop Y was selected because of the greater variety of furnace-design features, types of steel produced, and firing rates used. With the use of aspirating thermocouples, continuous gas analyzers, thermocouple and optical pyrometers, a study was made of: 1—effect of combustion-air temperature on open-hearth production rate, 2—thermal gradients present in various zones of the regenerative system, 3—effect of furnace-design variations on air temperature and heat recovery, 4-—effect of furnace-operating variables on heat recovery, and 5—variation in heat recovery with furnace age during the normal furnace campaign. Data collected on individual heats at 15 min intervals included air-flow rate, firing rate, checker temperature, combustion-air temperature, and furnace pressure. These data were collected on approximately 230 heats of steel. In addition, information was obtained at random on air infiltration and combustion-gas compositions. The data gathered have shown the desirability of closer control of open-hearth firing practices, a need for reducing air infiltration in the uptake zones, and a need for further study of design of checkers and of uptake-fantail areas. Equipment Air is practically a nonradiating medium. Consequently, in the measurement of air temperatures, the principle of heat conduction must be used rather than heat radiation. For this reason, aspirating-type thermocouple pyrometers normally are used to measure air temperatures. With these devices, air

Jan 1, 1956

By J. Hudy

An investigation has been made to determine the applicability of the Cendrex X-ray instrument for the measurement of the ash contents of washed bituminous coal products. The results obtained for selected products from five preparation plants in the northern Appalachian region are described. Emphasis of the study was placed on low-ash bituminous coals suit-able for utility or metallurgical markets. There was good agreement between the results obtained by conventional ash determination methods and by the Cendrex for all the products tested. A principal disadvantage of coal in competition with other fuels has been its inconsistent quality, especially with respect to ash content. Mine rnechanization and production from coalbeds of inferior quality have accentuated this failing. Present quality control methods in coal preparation plants are inadequate because (1) control samples taken over a production shift only serve to give the average quality of the product, (2) conventional sampling and analysis data are usually not available at the time a shipment is scheduled, and (3) the plant operator does not have the use of such data when the coal is being processed so that operating conditions may be adjusted for correcting variations in quality. Thus, the development and use of continuous-control monitoring instruments is of prime importance. The Federal Bureau of Mines arranged to investigate an instrument using x-rays for rapid continuous ash determinations. Developed by the Dutch State Mines and first described in 1958,' this instrument, which has found widespread acceptance in Europe, is designed to provide ash analysis of any desired coal feed or product stream with only a five-minute time lag between sample collection and analytical results. With limit controls, this unit could be used to feed back signals to preset the separating gravity of coal washers, control the ratio of various coals needed to produce an acceptable blend, and permit the sorting of a washed product into two qualities, one which is below and the other which is above a prescribed ash content. This unit can also be used discontinuously for rapid determination of coal samples taken in the usual manner. THEORY Di jkstra and Sieswerda of the Dutch State Mines studied the effect of chemical composition and ash content on the absorption coefficient of coal with the transmitted radiation method.' They found that with an X-ray wavelength of 1.79 A and values calculated for the absorption coefficients of ash and combustibles, the absorption coefficient of coal gave a linear relationship when plotted against the ash content. Thus, a method of measuring the absorption coefficient of coal could also be used to measure the ash content. However, practical attempts to measure the ash content of coal by comparing the intensities of the transmitted X-rays failed. The absorption coefficient of coal can also be obtained by irradiating a layer of coal with x-rays and measuring the intensity of the diffused reflection (backscatter method). The relationship between the diffused reflection and the ash content is actually hyperbolic but approximates a straight line over a narrow range. A measuring circuit that balanced the difference in intensity of the reflected radiation from a standard surface against that from a coal sample was used. By plotting this difference of reflected radiation against the ash content, a curve which approximated a straight line over a range of 8 percentage points of ash was obtained. DESCRIPTION OF EQUIPMENT The apparatus performs two distinct functions: (1) the preparation of the sample to a suitable size consist and moisture content for delivery to the x-ray element, and (2) the measurement of the ash content by the x-ray element. In a continuous operation the coal sample is delivered to a conditioner where it is dried to a maximum of 1% surface moisture and pulverized in a high speed mill to -48-mesh. This material is fed, at a rate of 250-300 gpm onto a rotating disk, shown in Fig. 1, where it is mixed with material already present. The mixture is rotated on the disk and

Jan 1, 1969