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By Ferit Gurses

EXTENSIVE coal and lignite deposits exist in Turkey. Bituminous coal is the nation's principal mineral resource; important not only as fuel for the industrial development of the country, but also as a means of obtaining foreign exchange. Of the electrical power generated during 1939, 82.8 per cent was derived from coal.1 It is anticipated that the lignite deposits will be one of the major sources of power for the electrification of the country. BITUMINOUS COAL The locations of the four principal bituminous-coal2 basins are indicated on Fig. 1. The Eregli-Zonguldak basin lies on the Black Sea northwest of Ankara; the Canakkale basin lies near the junction of the Dardannelles; the Trakya basin is in European Turkey northwest of the Bosphorus and the Erzurum basin lies far to the east. The Eregli-Zonguldak basin is the most important of the four. This coal basin was discovered in 1829 but did not arouse interest until 1848; up to 1865, its annual production had not exceeded 50,000 metric tons. In 1865, during the Sultanate, working of coal mines was started by the Navy department, and the annual production was 61,145 metric tons. In 1908, the Minister of Commerce and Agriculture was authorized to develop the whole coal basin. Production reached 264,397 metric tons in 1910, and during 1915-1922, preceding the revolution, the total production of the basin was 2,676,043, or an average of 334,000 metric tons annually. The period of national revolution that followed was marked by a steady increase in coal production in Turkey, although world production decreased, because of the crisis of 1929-1932, about 52 per cent. AREA AND GEOLOGY OF THE COAL BASIN The geology of the Eregli-Zonguldak area is not yet completely known. The basin begins at Gungazi, to the west of Eregli, and extends to Sogutozu, a distance of about 106 miles. The coal beds, however, appear only in places and the overlying Cretaceous strata hide them elsewhere. This area includes the most important centers, such as Kandilli, Alacaagzi, Teflenli, Kozlu, Gelik (see Fig. 2). The geological sequence of the district is correlated with the Cretaceous of the Balkans; which is, in turn, a prolongation of the Alpine zone. Geological surveys made by G. Ralli, R. Zeiller and P. Arni3 show that the Eregli-Zonguldak formations fall into three natural divisions. Series a, The Alacaagzi in the district of that name (Fig. 2), is of the Culm stage. The strata strike generally east-west and dip about 30° south. This series appears also around Kandilli and Camli, with a steeper angle of dip, but the deposits there lack regularity. The Alacaagzi stage appears also farther east, to the south of Kozlu and Gelik. The Alacaagzi series contains 15 seams of an average thickness of 2 ½ ft. of good coal. Series b, the Kozlu, best represented in Zonguldak, Kilimli, Catalagzi, and between

Jan 1, 1944

By H. R. Nelson, Martin S. Maier

The diffusion of metals plays an important role in many metallurgical processes,lJ as, for example, the formation of alloys by the annealing of mixed powders, the homogenization of segregated alloys, and the carburization of steel. Other equally important phenomena, such as recrystalli-zation and creep, are based on the movement of like atoms. Although much is known concerning the effects of diffusion in metals, very little is known concerning the details of the physical processes involved. 1,3-5 The data that should give most information concerning the processes involved in diffusion are those on the diffusion of like atoms—self-diffusion. Very little is known concerning the rates of self-diffusion of metals because before the discovery of artificial radioactivity in 1934 there was no means of detecting the movement of the diffusing atoms through the solvent metal except in the elements possessing natural radioactive isotopes—lead, thallium and bismuth. Using the induced radioactivity of the element as an indicator, atoms can now be "tagged" so that the rate of diffusion of the radioactive isotopes of an element (tagged atoms) into the stable isotopes of the same element can be measured. As the radioactive and stable isotopes of an element differ only in nuclear structure, it is quite certain that all isotopes of an element diffuse at the same rate. Two techniques have been used to measure self-diffusion. In one, a thin layer of radioactive metal is deposited on the face of the solvent metal, and the decrease in the surface activity as the radioactive atoms diffuse into the solvent metal is measured. This method has been used to determine the coefficients of self-diffusion of lead6-l0 and bismuth10 using natural radioactive isotopes, and of gold1' and copper12 using artificial radioactive isotopes. In the other technique a thin layer of the radioactive metal is deposited oil one face of the solvent metal, and after diffusion has occurred the specimen is cut in thin sections to obtain the concentration-penetration curve. This method has been used to determine the coefficients of self-diffusion of gold,13 zinc,14-l6 silver," and copper.17 The second method was used for the work described in this paper. Materials The coefficients of self-diffusion were determined in two grades of polycrystalline copper and in single crystals of copper. Commercial OFHC copper was used in the form of disks I in. in diameter by % in. thick. Samples of high-purity copper described by Phillips and Skinnerl9 were supplied through the courtesy of the American Smelting and Refining Co. The high-purity copper rod was used without remelting by cross-rolling to a thickness of 0.075 in., from which disks 7/8 in. in diameter were cut. A good grade of bus-bar copper was used to make the single crystals.

Jan 1, 1942

By Martin S. Maier, H. R. Nelson

The diffusion of metals plays an important role in many metallurgical processes,lJ as, for example, the formation of alloys by the annealing of mixed powders, the homogenization of segregated alloys, and the carburization of steel. Other equally important phenomena, such as recrystalli-zation and creep, are based on the movement of like atoms. Although much is known concerning the effects of diffusion in metals, very little is known concerning the details of the physical processes involved. 1,3-5 The data that should give most information concerning the processes involved in diffusion are those on the diffusion of like atoms—self-diffusion. Very little is known concerning the rates of self-diffusion of metals because before the discovery of artificial radioactivity in 1934 there was no means of detecting the movement of the diffusing atoms through the solvent metal except in the elements possessing natural radioactive isotopes—lead, thallium and bismuth. Using the induced radioactivity of the element as an indicator, atoms can now be "tagged" so that the rate of diffusion of the radioactive isotopes of an element (tagged atoms) into the stable isotopes of the same element can be measured. As the radioactive and stable isotopes of an element differ only in nuclear structure, it is quite certain that all isotopes of an element diffuse at the same rate. Two techniques have been used to measure self-diffusion. In one, a thin layer of radioactive metal is deposited on the face of the solvent metal, and the decrease in the surface activity as the radioactive atoms diffuse into the solvent metal is measured. This method has been used to determine the coefficients of self-diffusion of lead6-l0 and bismuth10 using natural radioactive isotopes, and of gold1' and copper12 using artificial radioactive isotopes. In the other technique a thin layer of the radioactive metal is deposited oil one face of the solvent metal, and after diffusion has occurred the specimen is cut in thin sections to obtain the concentration-penetration curve. This method has been used to determine the coefficients of self-diffusion of gold,13 zinc,14-l6 silver," and copper.17 The second method was used for the work described in this paper. Materials The coefficients of self-diffusion were determined in two grades of polycrystalline copper and in single crystals of copper. Commercial OFHC copper was used in the form of disks I in. in diameter by % in. thick. Samples of high-purity copper described by Phillips and Skinnerl9 were supplied through the courtesy of the American Smelting and Refining Co. The high-purity copper rod was used without remelting by cross-rolling to a thickness of 0.075 in., from which disks 7/8 in. in diameter were cut. A good grade of bus-bar copper was used to make the single crystals.

Jan 1, 1942

By W. D. Steele, S. D. Brady

The Pittsburgh coal seam in West Virginia contains the largest coal reserves of any coal seam in that State and is, therefore, one of the most important seams, and attains minable thickness and purity throughout that part of the seam extending from the Northern Panhandle to Monon-galia Co. thence south and southwest across the state to Wayne Co. near Hunt-ington. The Pittsburgh coal is also minable in the Upper Potomac region but is now practically exhausted there. The total minable areas of this coal amount to 2,165 sq miles and are estimated, by the West Virginia Geological Survey, to contain 13¼ billion net tons. The largest body of Pittsburgh coal outcrops on the western edge of West Virginia, along the Ohio River as far south as Moundsville, West Va., going under the river at that point and extending at various depths down the river as far as Wetzel Co. line where it thins out to such an extent that it has little practical value, and on the eastern edge this large body outcrops along the Monongahela River. The territory to be covered by this paper is the area known as the Northern West Virginia District comprising Wetzel, Mon-ongalia, Marion, Preston, Harrison, Dodd-ridge, Taylor, Barbour, Upshur, Lewis, Gilmer, Braxton and Calhoun Counties, and is also known as Dist. 3 under the Bituminous Coal Act. This region was originally opened for commercial mining along and adjacent to the Monongahela River around 1852 when the Baltimore and Ohio Railroad was constructed to Fairmont. It has been extensively developed, first, in 1880 (when the Monongahela River Railroad, now B. & 0. R. R., was constructed) between Fairmont and Clarksburg, and later, in 1916, between Morgan-town and Fairmont when the Monongahela Railway was constructed and placed in operation, this area furnishing the major portion of the production over the past years. With the mining out of a great deal of this territory adjacent to the Mononga-hela River considerable interest has been developed in the back acreage; and within the past few years a number of diamond core drill holes have been made in the back areas of Monongalia and Marion Counties. In this back area the oil and gas well drilling showed that the Pittsburgh coal seam was of minable thickness and ranged in depth from 350 to 1,000 ft below the surface of the stream valleys but this drilling did not furnish any definite data as to its thickness and quality. Economic Importance The Pittsburgh seam in Northern West Virginia is of primary importance as a coal resource not only because of its large reserves but because of its contributing a very large part of the coal used in this country for general steam uses. The Pittsburgh seam is a consistently thick seam, averaging 8 ft in thickness, with very easy grades underground, so it has always been

Jan 1, 1949

By James W. Shaffer

Aluminum is the most abundant metallic element and forms 8% of the earth's crust. Because of its chemical activity it does not occur in nature in a metallic form but principally in the silicates, feldspar, mica, shale, and clay. Bauxitic raw materials-bauxitic clay, aluminous laterite, and bauxite-develop from these aluminum silicate sources. Bauxite and aluminous laterite are naturally occurring mixtures of aluminum hydroxides and mineral impurities, and they are the major sources of aluminum. End Uses Bauxite is the basic ore of the aluminum industry. It is refined into aluminum hydroxide and calcined for feed stock to electrolytic smelters. Over 90% of the tonnage mined is refined and smelted into aluminum. The total tonnage consumed by other industries is small in comparison, but bauxite and alumina are important for the manufacture of refractories, ceramics, chemicals, abrasives, pharmaceuticals, catalysts, cements, dessicants, and flame retardants. Some aluminum-containing industrial products are made from clays and other materials but the majority originate from bauxite directly or from aluminum hydroxide and alumina refined from bauxite. Lateritic type bauxite is also used as building and decorative stone. Geology Mineralogy and Properties Bauxite is a mineral raw material composed principally of one or more aluminum hydroxide minerals and impurities of silica, iron oxide, titania, and other elements in minor or trace amounts. The important aluminum hydroxide minerals are gibbsite, boehmite, and diaspore. Bayerite, nordstrandite, and tucanite are naturally occurring aluminum hydroxides but are rare and not commercially important. Mixtures of gibbsite and boehmite are common, boehmite and diaspore less common, and gibbsite and diaspore rare. Gibbsite is aluminum trihydroxide. Boehmite and diaspore are aluminum oxide hydroxides and have essentially the same composition, but diaspore has a greater hardness and a more tightly bonded and denser atomic structure. Although not technically correct, the commercial terms trihydrate and monohydrate are frequently used to distinguish types of bauxite. If bauxite is all or nearly all gibbsite, it is referred to as a trihydrate ore; if boehmite or diaspore or a mixture of both are the dominant minerals, the bauxite is called a monohydrate ore. If substantial amounts of both gibbsite and boehmite are present, the bauxite is frequently referred to as a mixed ore. Properties of major bauxite minerals are shown in Table 1. Silica, iron oxides, and titania are major impurities always present in deposits of bauxitic raw materials.. Silica impurities usually occur as clay minerals, micaceous minerals, or quartz, but cristobalite and feldspar are found in some deposits. The most common clay minerals are kaolins; however, illites and chlorites are often found in small quantities. Varying proportions of aluminum, iron, and clay minerals make bauxite, aluminous laterite, ferruginous laterite, and bauxitic clay deposits gradational with each other. Hematite and goethite are the common iron mineral impurities in many bauxites. Magnetite and ilmenite occur in deposits derived from basic igneous rocks. Other iron minerals associated with bauxite are maghemite, pyrite, siderite, and marcasite. The titanium minerals found in bauxites are anatase, leucoxene, rutile, ilmenite, titaniferous

Jan 1, 1983

The San Manuel district of Arizona was first prospected prior to the Civil War, but there was little or no production until 1881. Small operators tried to develop ore bodies from time to time after that without success. Then, in 1917, a drilling program was carried out; but it did not indicate a copper content of interest. Finally, in the 1940s, the U. S. Geological Survey drilled the property and obtained indications of a mineralized area. At that time, Magma Copper and its principal owner, Newrnont Mining Corporation, drilled many deep holes through the gravels and conglomerates and in 1948 proved an ore reserve of 367 million tons of 0.785% copper sulfide ore. Underground exploration and development were started in early 1948, and in 1953 design and construction of the surface facilities commenced. By the end of 1955 plant construction was completed. The ore deposit of disseminated pyrite, chalcopyrite, chalcocite, molybdenite, silver, and gold is in quartz monzonite porphyry gangue. Mine production, which is entirely underground, is by full-gravity block-caving. Initially, ore mined at a rate of 36,000 tpd was hoisted through two identical shafts. From the 5,000 ton coarse ore bins located at the collar of each shaft, the ore was hauled by a shuttle service rail- road in 100-ton bottom-dump rail cars a distance of seven miles to the rail bin. Fragmentation from block-caving supplemented by underground grizzlies at the loading stations controlled the oversize material to give a feed size acceptable to the two 7 ft standard Syrnons crushers. During operation, however, it became evident that a large amount of secondary breaking in the grizzlies was necessary to produce a suitable feed for the standard crushers. The decision was then made to install primary gyratory crushers on the surface adjacent to the shaft site ore bins. Under each 5,000-ton coarse ore bin, an 8ft by 20 ft (2.44 m by 6. 1 m) apron feeder transfers the ore to a 13 ft 6 in. by 10 ft (4. 1 m by 3. 05 m) grizzly set at 6 in. (152 mm) and sloped at 45 degrees. About 65% of the ore passes the grizzly and thus bypasses the 42 in. by 65 in. (1.07 m by 1. 65 m) Allis -Chalmers gyratory equipped with a Hydroset mechanism and having an open side setting of 5 ½ in. (140 mm). Grizzly undersize and crushed ore drop onto a 6 ft by 30 ft (1. 83 m by 9. 14 m) variable- speed apron feeder for transfer to a 54 in. by 90 ft 5 in. (1.37 m by 27.6 m) inclined conveyor equipped with a tramp iron detector. Indication of tramp iron automatically stops the conveyor and both apron feeders. When the iron is removed from the belt by the operator,

Jan 1, 1978

By W. R. Aufricht, E. H. Koepf

The theory, measurement, and application of capillary forces in reservoir rock have been treated ex-tensively in the various petroleum publications.1,2,3,4 These forces are of prime importance in oil production, and data on capillary properties are among the most important tools used in the study of reservoir mechanics. The principal application of measured capillary pressure data by the production and reservoir engineer is in the determination of the initial distribution and mobility of fluids in the reservoir. The distribution refers to the magnitude of the oil and interstitial water saturations under capillary equilibrium conditions and to their variation throughout the reservoir as a result of changes in rock properties and nearness to free water. The magnitude of the water (or oil) saturation, as well as the porosity, is required in volumetric calculations of oil in place. In low permeability reservoirs, where long transition zones are common, the magnitude of the oil content, even below the depth interval where commercial rates of flow of oil can be obtained, must be evaluated since this oil contains energy available to the production of the remainder of the reservoir. The mobility of the water phase is of particular importance in water-flood calculations since mobile water may condemn what would otherwise be a successful water flood. In reservoirs with predominantly small pores, high immobile water contents are possible. Conversely, reservoirs with predominantly large pores may contain mobile water even though the interstitial water contents are relatively low. This presentation reviews the distribution and mobility of interstitial water contents as determined from capillary pressure data and shows typical data for various types of carbonate reservoirs. A discussion of the variations found in different types of carbonate reservoirs is given. DISCUSSION Interpretation of Laboratory Data Fig. 1 is a typical laboratory capillary Pressure curve where water saturation as Per cent of Pore space is plotted vs capillary Pressure (psig) for an air-water system. This par- ticular curve was obtained by measurement on a sample of San Andres dolomite with intergranular-type porosity. The sample studied had a permeability of 10.0 md and a porosity of 18.8 per cent. The capillary pressure-saturation relationship illustrated is an inherent property of the rock (a function of the size and distribution of the pores) and represents the ability of this water-wet rock to retain water against the pressure differential exerted by a non-wetting fluid (oil or gas) to remove it. In the laboratory a known pressure differential is exerted from a pressure source; in the reservoir the pressure differential is controlled by the density difference between the hvdrocarbons and the water. The laboratory capillary pressure values may be converted into terms of equivalent height of water column using known values of reservoir oil and water density and measured or average values of interfacial tension

Jan 1, 1958

By Ferit Gurses

Extensive coal and lignite deposits exist in Turkey. Bituminous coal is the nation's principal mineral resource; important not only as fuel for the industrial development of the country, but also as a means of obtaining foreign exchange. Of the electrical power generated during 1939, 82.8 per cent was derived from coal.' It is anticipated that the lignite deposits will be one of the major sources of power for the electrification of the country. Bituminous Coal The locations of the four principal bituminous-coal2 basins are indicated on Fig. 1. The Eregli-Zonguldak basin lies on the Black Sea northwest of Ankara; the Canakkale basin lies near the junction of the Dardannelles; the Trakya basin is in European Turkey northwest of the Bosphorus and the Erzurum basin lies far to the east. The Eregli-Zonguldak basin is the most important of the four. This coal basin was discovered in 1829 but did not arouse interest until 1848; up to 1865, its annual production had not exceeded 50,000 metric tons. In 1865, during the Sultanate, working of coal mines was started by the Navy department, and the annual production was 61,145 metric tons. In 1908, the Minister of Commerce and Agriculture was authorized to develop the whole coal basin. Production reached 264,397 metric tons in 1910, and during 1915-1922, preceding the revolution, the total produc- tion of the basin was' 2,676,043, or an average of 334,000 metric tons annually. The period of national revolution that followed was marked by a steady increase in coal production in Turkey, although world production decreased, because of the crisis of 1929-1932, about 52 per cent. ARea and Geology of the Coal Basin The geology of the Eregli-Zonguldak area is not yet completely known. The basin begins -at Gungazi, to the west of Eregli, and extends to Sogutozu, a distance of about 106 miles. The coal beds, however, appear only in places and the overlying Cretaceous strata hide them elsewhere. This area includes the most important centers, such as Kandilli, Alacaagzi, Teflenli, Kozlu, Gelik (see Fig. 2). The geological sequence of the district is correlated with the Cretaceous of the Balkans; which is, in turn, a prolongation of the Alpine zone. Geological surveys made by G. Ralli, R. Zeiller and P. Arni3 show that the Eregli-Zonguldak formations fall into three natural divisions. Series a, The Alacaagzi in the district of that name (Fig. 2), is of the Culm stage. The strata strike generally east-west and dip about 30" south. This series appears also around Kandilli and Camli, with a steeper angle of dip, but the deposits there lack regularity. The Alacaagzi stage appears also farther east, to the south of Kozlu and Gelik. The Alacaagzi series contains 15 seams of an average thickness of 2 ft. of good coal. Series b, the Kozlu, best represented in Zonguldak, Kilimli, Catalagzi, and between

Jan 1, 1944

By Ferit Gurses

Extensive coal and lignite deposits exist in Turkey. Bituminous coal is the nation's principal mineral resource; important not only as fuel for the industrial development of the country, but also as a means of obtaining foreign exchange. Of the electrical power generated during 1939, 82.8 per cent was derived from coal.' It is anticipated that the lignite deposits will be one of the major sources of power for the electrification of the country. Bituminous Coal The locations of the four principal bituminous-coal2 basins are indicated on Fig. 1. The Eregli-Zonguldak basin lies on the Black Sea northwest of Ankara; the Canakkale basin lies near the junction of the Dardannelles; the Trakya basin is in European Turkey northwest of the Bosphorus and the Erzurum basin lies far to the east. The Eregli-Zonguldak basin is the most important of the four. This coal basin was discovered in 1829 but did not arouse interest until 1848; up to 1865, its annual production had not exceeded 50,000 metric tons. In 1865, during the Sultanate, working of coal mines was started by the Navy department, and the annual production was 61,145 metric tons. In 1908, the Minister of Commerce and Agriculture was authorized to develop the whole coal basin. Production reached 264,397 metric tons in 1910, and during 1915-1922, preceding the revolution, the total produc- tion of the basin was' 2,676,043, or an average of 334,000 metric tons annually. The period of national revolution that followed was marked by a steady increase in coal production in Turkey, although world production decreased, because of the crisis of 1929-1932, about 52 per cent. ARea and Geology of the Coal Basin The geology of the Eregli-Zonguldak area is not yet completely known. The basin begins -at Gungazi, to the west of Eregli, and extends to Sogutozu, a distance of about 106 miles. The coal beds, however, appear only in places and the overlying Cretaceous strata hide them elsewhere. This area includes the most important centers, such as Kandilli, Alacaagzi, Teflenli, Kozlu, Gelik (see Fig. 2). The geological sequence of the district is correlated with the Cretaceous of the Balkans; which is, in turn, a prolongation of the Alpine zone. Geological surveys made by G. Ralli, R. Zeiller and P. Arni3 show that the Eregli-Zonguldak formations fall into three natural divisions. Series a, The Alacaagzi in the district of that name (Fig. 2), is of the Culm stage. The strata strike generally east-west and dip about 30" south. This series appears also around Kandilli and Camli, with a steeper angle of dip, but the deposits there lack regularity. The Alacaagzi stage appears also farther east, to the south of Kozlu and Gelik. The Alacaagzi series contains 15 seams of an average thickness of 2 ft. of good coal. Series b, the Kozlu, best represented in Zonguldak, Kilimli, Catalagzi, and between

Jan 1, 1944

By David Cornell

Back pressure test data on natural gas wells are short time test data of unsteady state nature. Performance curves from which unsteady state effects have been eliminated, called stabilized performance curves, are necessary for understanding the behavior of gas wells and for scheduling gas fields for periods up to 20 years. A calculation procedure has been developed whereby three day, seven day, 30 day, or other duration stabilized performance curves may be calculated from back pressure test data. Such curves are essential for correct gas deliverability calculations and gas field scheduling. I NTRODUCTION The manner in which a back pressure test is made will affect the slope of the back pressure curve because the radius of drainage changes with the length of time that the well is allowed to flow. The reciprocal of the slope of the back pressure curve is defined as n in Equation 1 and varies from 0.5 to 1.0. If the flow is viscous and the radius of drainage constant, n will have a value of 1.0. Because of turbulence in the formation near the wellbore, the pressure drop is usually greater than the viscous flow pressure drop and the exponent n is frequently less than 1.0. In addition, since the radius of drainage moves away from the well-bore during the test, the gas flows a greater and greater distance as the test proceeds, with a resulting increased pressure drop at the high flow rates, and, again, n for the test tends to be less than 1.O. The effect of the changes in the radius of drainage may be calculated and the results used in preparing stabilized performance curves for fixed values of the radius of drainage. Such curves can be made for a defi- nite time period, such as three day, seven day, or 30 day stabilized performance curves. These cukes will show the effect of turbulence near the wellbore and can be used to predict the performance of the gas well at any flow rate or for any production period. In order to discuss the importance of the radius of drainage quantitatively, it should be defined. Muskat" defines the radius of drainage as follows: "... the radius of drainage gives the distance from the well to which the approximately steady state condition has been established ... it being assumed that no gas is removed from any point until the radius of drainage has passed that uoint." An eauivalent definition of the radius of drainage is that radius at which the extrapolated portion of the steady state portion of the pressure gradient gives a pressure equal to the shut-in reservoir pressure. This definition is also implied in the back pressure equation. The radius of drainage is, then, the distance into the reservoir from which the gas appears to originate at any time. It is, however, only a useful concept and does not actually exist. Fig. 1 illustrates the definition of the radius of drainage. At the end of each flow period the radius of drainage may depend on three factors: (1) the duration of each flow period; (2) the rate of gas production; and (3) the rate and duration of the previous flow periods. In general, back pressure tests are conducted with various lengths of production time and at various flow rates. Each individual back pressure test, therefore, requires an individual analysis. The calculations of the change in the radius of drainage have been made, however, for the case of equal flow periods for all four production rates and several sets of increasing flow rates. Fig. 2 illustrates the results of such calculations made by the method of Cornell and Katz2 for the case of 8, = 50,000 and the flow rate increasing in the ratio 1.0:2.0:3.0:4.0 for each flow period. The increase in the radius of drainage during the test is apparent.

Jan 1, 1956

By Samuel Dolbear

PUBLIC discussions of mine finance in the tech-nical press have been confined mainly to methods of providing funds for the development of pros-pects or other mining operations which have not reached the stage of productivity. The application of modern financing methods to mines which have behind them a successful record of net earnings has, for some reason, been given scant consideration by mine owners and managers. In a few conspicuous cases, such for example as the Anaconda Copper Mining Co., Chile Copper Co., and one or two others, industrial finance has been applied to mining operations on the scale and after the fashion of other operations. When extensions are needed re-course is usually had, however, to the sale of common stock, with the obvious disadvantage of diluting the holdings of every stockholder of record prior to such financing. In some cases, it has been sought to over-come this disadvantage by issuing stock purchase rights to shareholders of record. If the stockholder is in a position to acquire additional stock, he may then pre-serve his interest intact, otherwise he must suffer a dilution of his holding. If he purchases additional stock he is, from one point of view, paying more for his in-terest than he bargained for when he made his original purchase. In many cases development and equipment are paid for out of surplus or current earnings. It is sometimes most difficult to explain to a manager why he can afford to borrow money when funds are available from a sur-plus account. Nevertheless, industrial enterprises with adequate surplus accounts often finance new construc-tion by the issuance of bonds. Such a procedure enables the company to maintain its surplus intact, and to con-tinue the payment of dividends during a temporary period of unusual expenditures.

Jan 2, 1927

By T. J. Fabiniak, R. A. Dodd, R. Balow

ALTHOUGH the (111) slip direction in pure bcc metals is well established, the information on operative slip planes is less unambiguously interpreted. So far, (110) {112), and (123) slip planes have been identified, but it is not certain whether glide on (112) and (123) really occurs or if it is composite slip on non-parallel (110) planes. The second of these possibilities is supported by the work of Chen and Maddin on niobium and molybdenum, and a subsequent analysis by these same workers of slip in bcc metals generally.3 The alternative possibility is exemplified by the work of Opinsky and smoluchowsky4 who concluded that slip in Fe-Si crystals can occur on any one of the systems {110}(111), {112}(111), and {123)(111), depending on which system the resolved shear stress is highest. Allen et alS5 also found that glide in ar iron could occur on any of these three systems, the operative system being determined principally by orientation. By an analysis of crystal rotation, slip lines, and X-ray asterism Harris6 concluded that niobium also deforms on these same systems, but if one of these glide planes does not coincide with the plane of maximum resolved shear stress, composite slip on nonparallel (110) planes may occur giving a macroscopic high indices slip plane. Earlier work on iron by Vogel and Brick reached the same conclusion.7 The analysis of slip in bcc metals is made more difficult by the fact that the slip lines may be quite wavy. In fact, the generality of wavy slip lines suggests that screw dislocations slip readily from one plane to another in the (111) zone ("pencil glide") although, as noted, it is not certain whether planes other than (110) really contribute to the slip. If planes of higher indices than {110} do operate, there is a possibility they may do so more readily at higher temperature Argon and Maloof9 observed {100}{211}(111) slip in tungsten single crystals plastically strained at low temperatures, but the results were interpreted in terms of an orientation-dependence rather than temperature-dependence. Therefore, at the present time corroborative evidence for the operation of higher indices slip planes at higher temperatures is lacking. The present results were obtained during the course of an investigation into the effect of cathode and anode surface crystallography on the prebreakdown currents of vacuum insulated devices. In the experiment of particular interest, the 1/8-in.-diam anode and the in.-diam cathode were tungsten crystals (total impurities -230 ppm) with (110) and (100) faces respectively. The faces were electrolytically planed and examined for initial perfection by plastic/carbon replicas and a study of Kikuchi lines in reflection electron diffraction patterns. They were aligned precisely parallel in an insulating holder incorporated into the electron microscope, the measured microscope vacuum being 2 x 10-5 torr, and the electrode spacing 0.01524 cm. The anode structure shown in Fig. 1 was obtained

Jan 1, 1970

By Ralph H. Sweetser

In these days of the almost exclusive use of byproduct coke as the blast-furnace fuel in this country, it may seem out of place, and smacking too much of reminiscing, to say anything about the use of anthracite coal for blast-furnace fuel. Viewed in the light of present day research and of developments in alloy steel, some observations seem appropriate regarding this raw material that played such an important part in the development of the iron and steel industry during 50 years of the past century. The research work of that period, in which the whole iron and steel industry was revolutionized, passing from wrought iron to steel and from charcoal to three new mineral fuels for blast furnaces, was done chiefly in the full-sized plants of that day; and it was done largely by the ironmasters themselves. The laboratory had not become a part of the ironworks, and scientific instruments were lacking around the blast furnaces; "rule o' thumb" and erroneous theories prevailed—and have not yet all been eliminated. The recent interest in meteoric iron in connection with nickel steels and other alloys proves that it is worth while to search for the reasons for excellence and the causes for failures in the metallurgy of bygone days. Turner1 gives the reasons why the blast furnace of Dr. F. W. Geissen-hainer on Silver Creek, Schuylkill County, Pennsylvania, about 10 miles northeast of Pottsville, was operated successfully with anthracite2 in August and September, 1836, and why several other attempts failed. It has taken a long time for us to find out that there are great differences in the behavior of anthracites from the several parts of the anthracite region, as well as differences in coking coals from the bituminous fields.

Jan 1, 1935

By Ralph H. Sweetser

In these days of the almost exclusive use of byproduct coke as the blast-furnace fuel in this country, it may seem out of place, and smacking too much of reminiscing, to say anything about the use of anthracite coal for blast-furnace fuel. Viewed in the light of present day research and of developments in alloy steel, some observations seem appropriate regarding this raw material that played such an important part in the development of the iron and steel industry during 50 years of the past century. The research work of that period, in which the whole iron and steel industry was revolutionized, passing from wrought iron to steel and from charcoal to three new mineral fuels for blast furnaces, was done chiefly in the full-sized plants of that day; and it was done largely by the ironmasters themselves. The laboratory had not become a part of the ironworks, and scientific instruments were lacking around the blast furnaces; "rule o' thumb" and erroneous theories prevailed—and have not yet all been eliminated. The recent interest in meteoric iron in connection with nickel steels and other alloys proves that it is worth while to search for the reasons for excellence and the causes for failures in the metallurgy of bygone days. Turner1 gives the reasons why the blast furnace of Dr. F. W. Geissen-hainer on Silver Creek, Schuylkill County, Pennsylvania, about 10 miles northeast of Pottsville, was operated successfully with anthracite2 in August and September, 1836, and why several other attempts failed. It has taken a long time for us to find out that there are great differences in the behavior of anthracites from the several parts of the anthracite region, as well as differences in coking coals from the bituminous fields.

Jan 1, 1935

By J. E. Miller, W. E. DeVaney, L. Stroud

During a recent phase study of a natural gas, two stable equilibrium liquid phases were observed at temperatures below —200°F and pressures above 200 psi. This paper reviews the published literature on the occurrence of multiple equilibrium liquid phases and presents analytical data for the vapor and two equilibrium liquid phases of the liquefied natural gas at five experimental conditions. In addition, data for 30 conditions of two-phase equilibria are included. INTRODUCTION The low-temperature phase behavior of gases, most of which contained helium, has been investigated in the laboratories of the Helium Activity for many years. Since 1952, experimental studies of these systems have been continuous as part of the research program at Amarillo, Tex. Because of their value to private industries interested in participating in the Helium Conservation Program, several "Open File" reports containing phase equilibria data for heliurn-bearing natural gases have already been released by the Helium Activity. A paper containing information on the general phase behavior, operating criteria and extensive vapor-liquid data for two helium-containing systems was recently published.2 Additional publications presenting experimental data on the phase relationships of various gas systems are now in process and will be available in the near future. PREVIOUS EXPERIMENTAL WORK Although the formation of multiple liquids has been reported for various systems, to our knowledge this paper is the only substantiated evidence of a vapor-liquid-liquid equilibria in a naturally occurring gas. In 1940, Vink, Ames, and others13 reported the presence of two liquid phases in a hydrocarbon system consisting of mixtures of crude oils, solvents and natural gas. Eilerts and co-workers; published data on the recombined fluids from a gas-condensate well. This condensed gas, containing approximately 76 per cent methane and 24 per cent ethane-plus, exhibited two distinct liquid phases. Weinaug and Bradley 14 observed "unusual" phase behavior in a reservoir mixture. These workers postulated that the anomalous phase behavior was due to the "imminent formation of a second liquid phase". Botkin, Reamer, Sage and Lacey 1 studied two California crude oils that exhibited multiple phases. Kohn and Kuratal0 recently reported two equilibrium liquid phases in the methane-hydrogen sulfide system. Roof and Crawfordl1 and Eakin, et a16 also have reported experiments with binary systems that formed two stable equilibrium liquid phases. APPARATUS AND PROCEDURE A U. S. Bureau of Mines Phase Equilibrium Apparatus was used in conducting this study. The apparatus and procedures employed in its operation have been previously described3 and will not be repeated in detail ill this report. Briefly, the apparatus consists of a windowed cell which can be maintained within ±0.5°F for temperatures between room temperature arid -320°F. Pressure within the cell can be maintained within 0.1 per cent of gauge reading up to 800 psig. Equilibrium vapor and liquid samples are obtained in special containers4 for analysis by a mass spectrometer. Although the accuracy of the analyzer is about ±0.1 mol per cent, the reproducibility of the phase-equilibrium apparatus is considered relatively poor. Values reported from methane and nitrogen are considered accurate to ±l.0 and ±0.6 mol per cent. Data for ethane-plus in the vapor are accurate within 0.2 mol per cent; liquid-phase data for this aggregate compolnent are accurate within 1.5 mol per cent. For helium in the vapor phase, the analytical data are accurate within 0.2 mol per cent; liquid-phase analyses for this component were obtained by the charcoal adsorption method described by Frost8 and are accurate within 0.006 mol per cent. All of these references to the accuracy of reported values are conservative estimates based upon a statistical treatment of reproducibility data obtained with the apparatus.

By R. V. Smith

The theory for unsteady radial flow of gas, as simplified by Aronofsky and Jenkins, has been reviewed and compared with actual well performance. This study indicated that the theory should be modified by the introduction of an empirical "rate of flow" function "Y(q)". The expansion of the theory on the flow of gas to include a Y(q) term bridges the gap between the theory of unsteady-state flow of gas and actual gas-well behavior. Apparently, the Y(q) term is a function only of the rate of flow for a given well. The completion factor or skin effect is associated with the Y(q) function in such a manner that at least two or more sets of drawdown or pressure build-up tests are needed to separate the Y(q) function and the completion factor. Since the Y(q) function used in this report represents an energy loss dependent on rate of flow near the well-bore of a gas well which is in addition to the loss required by Darcy's law, the Y(q) function is related to the exponent of the back-pressure curve for a gas well. Techniques and equations are presented which permit the estimation of stabilized and "short-time" deliver-abilities. INTRODUCTION The published theory of radial unsteady-state flow of gas through porous media may be divided into papers1-" which use Darcy's law as a premise and other papers4-7,16-10 which recognize that Darcy's law may not hold for flow into gas wells. Miller8 compared theory based on Darcy's law with actual gas-well behavior and concluded that flow into gas wells deviates from Darcy's law. Houpeurt4,5 in a thorough investigation of flow into gas wells concluded that the flow rate into a gas well is proportional to the difference between the squares of upstream and downstream pressures elevated to a power between 1.0 and 0.5. Houpeurt also concluded that the deviation from Darcy's law is caused by irreversible, kinetic energy exchange between the flowing gas and the porous media. Tek9 presented a complete evaluation of the flow problem in gas wells. Several investigators state that the inclusion of gas compressibility into flow equations based on Darcy's law does not begin to explain the flow problems suggested by gas-well behavior. For many years, natural-gas engineers have realized that gas wells by actual test exhibit behavior which cannot be explained entirely by Darcy's law. Many tests on gas wells have indicated that a value of 0.85 for the exponent in the back-pressure equation is a fair average for many wells. However, Darcy's law either for steady or unsteady-state conditions indicates that the exponent should be 1.0. The purpose of this paper has been to examine this deviation from Darcy's law and to present a reasonable mathematical means of evaluating the deviation. The method presented in this paper combines previous theory with an empirical function to provide a description of gas-well behavior. All equations in this report are for constant terminal-rate-of-flow conditions. While present methods of testing wells usually are not based on this concept, they are believed to approach the constant terminal-rate conditions closely in many tests. However, several gas wells were tested by holding the rates of flow constant in order to approach more closely the constant terminal rate of flow; the results confirm the concepts presented in this paper. REVIEW OF THEORY FOR UNSTEADY-STATE FLOW OF GAS The basic partial differential equation for the flow of natural gas has been given in technical literature; the equation for a cylindrical reservoir with the well in the center is

By James Douglas

No one mill attribute it to the partiality of friendship if I claim for Thomas Sterry Hunt the right to a place among that little band of men whom nature has endowed with what seems an almost magical power of insight into her mysteries. But those of us who knew him well, while me never ceased to wonder at the breadth of his genius, the fertility of his imagination, and the wonderful capacity of his memory, learned that these native powers would have availed little to win him his rank in science, had they not been stimulated by ceaseless mental activity, indomitable perseverance, and unflagging industry. Thomas Sterry Hunt was born in Norwich, Connecticut, on September 5, 1826. He came on his mother's side from that good old stock which gave to Puritan England the gentle mystic Peter Sterry and that uncompromising preacher Thomas Sterry, who wrote the notable tract, " The Rot among the Bishops " in 1667, and that gave to New England Consider and John Sterry, the mathematicians. While lie was a child the family moved to Poughkeepsie on the Hudson. There the father died when Thomas, the oldest son, was twelve. The mother and her family of six young children returned to the old home in Connecticut. For a short time Thomas attended the public school; but it was for a short time only, as he, thus early, was required to share the burden of the family support and to seek employment. This he found first in a printing-office, then with an apothecary, afterwards in a book-store. The surroundings may have been congenial, but the occupation probably was not; for he re-

Jan 1, 1893

By HILLARY W.

THAT colleges and technical schools constitute a vital factor in our industrial system is being realized more and more of late years. Consequently it is desirable that there should be a constant interchange of ideas between the 'school and the industries and that there should be a more intimate contact between the student and his future employer. Business and industry demand certain proficiencies and qualifications of the student and he, in turn, sees certain rewards and advantages in the industry. . In a meeting of this kind, whose primary purpose is to promote a greater intimacy between the students and those men who are active in the mining profession, it is quite fitting that each state his demnds upon the other in order to establish a common understanding. It is probable that a student, not being conversant with actual conditions in the industry, may be unfair in what he asks of his employer. Therefore criticism, constructive or other- wise, is not only accepted, but is invited.

Jan 1, 1930

LIST OF REFERENCES COMPILED BY ENGINEERING SOCIETIES LIBRARY FUEL POSSIBILITIES IN STEEL MAKING. Iron Age, November 6, 1913, p. 1056-1059. Paper read before the American Iron and Steel Institute, by William Whigham. The author discusses the use of pulverized coal as a fuel for open-hearth furnaces. IMPROVED PULVERIZED FUEL FEED DEVICE. Iron Age, November 6, 1913, p. 1024. Brief description of the Dunn apparatus, especially intended for cement kilns, but used also in the nodulizing of iron ore. WIDER UTILIZATION OF PULVERIZED COAL, H. R. Barnhurst. Iron Age, October 23, 1913, p. 906-908. Part of discussion of paper by James Lord on The Use of Pulverized Fuel in Metallurgical Furnaces, read before the Engineers' Society of Western Pennsylvania. POWDERED COAL FOR OPEN HEARTH FURNACES. Iron Age, October 16, 1913, p. 855. Abstract from the "Coal and Coke Operator." USE OF PULVERIZED COAL AS A FUEL FOR BOILERS, R. C. Carpenter. Sibley Journal of Engineering, December 1913, p. 85. COAL-DUST FIRED BOILER. Indian Engineering, November 29, 1913, p. 301. PROGRESS IN FUEL UTILIZATION. Mining and Scientific Press, October 25, 1913, p. 638. BUFFALO GRAIN-ELEVATOR DUST EXPLOSION. Engineering News, July 31, 1913, p. 223-24. Reprinted in the National Fire Protection Association Quarterly, October, 1913, p. 149-151. Mention is made of the danger of explosions in connection with the burning of powdered coal. POWDERED FUEL AND EXPLOSIONS. Railway Age Gazette, July 18, 1913, p. 53-84. Letter by W. D. Wood. USE OF PULVERIZED COAL IN METALLURGICAL FURNACES, James Lord. Engineers' Society of Western Pennsylvania, Proc., October, 1913, p. 363-371; discussion, p. 371-417. With bibliography.

Jan 3, 1914

By John H. Hollomon

In a recent paper,' a very early suggestion by Ludwik2 concerning the nature of the mechanical behavior of metals has becn reexamined and extended. In essence it was suggested that there exists, at least under certain conditions, a mechanical equation of state; that the stress required for flow depends upon the instantaneous values of the strain, strain rate, and temperature, and not upon their past values. It is proposed that under these circumstances thc stress does not depend upon past history of these variables, but is like the temperature of a gas that depends only upon the instantaneous values of the pressure and volume. This notion has not been applied to present-day studies of metals, though it is especially applicable to the study of creep. It is the purpose of this paper to analyze the significance and possible range of applicability of this idea and to determine how it influences the accepted ideas concerning creep. Stress-strain Relations It is wcll known that the stress-strain curves of metals are influenced by both train rate and temperature. For a fixed strain rate and temperature there is associated with each metal a stress-strain curve. If either the strain rate or temperature is changed a new stress-strain curve will be characteristic (Fig. I). A much more genera1 relation between the effects of these variables is possible, however. Consider the stress-strain curves of Fig. I determined at

Jan 1, 1947