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By R. K. Hopkins

For a great many years fusion welding has been used in and around petroleum refineries, but it is only within six or seven years that the more important pressure vessels have been constructed by this process, because before that time the properties of fusion welds would not withstand such rigorous service. Since the adoption of fusion welding for the construction of this equipment, the refiner has required pressure vessels suitable for operation over a very wide range of conditions. On the one hand, vessels must operate at extremely high temperatures, in the range of 950" to 1000° F., and on the other vessels must be suitable for operation at sub-zero temperatures down as low as —75" F. Also, vessels are required suitable for operation at pressures upwards of 1000 lb. per sq. in., and as low as a 29-in. vacuum. In addition, vessels are required to withstand the attack of very corrosive mediums. It has been a rather difficult task for the fabricator to meet all of these requirements, but as a result of the extensive research carried on by steel manufacturers and several fabricators of class I vessels, practically all of these demands have been met. In order to meet the refiners' requirements for this wide range of conditions, the fabricator has worked closely with the metallurgist. This has enabled him to choose the proper base metal for each service condition, but it has been the fabricator's problem to develop a welding rod and welding technique, as well as a heat-treatment, that would produce in the welded vessel characteristics in and around the weld comparable to those in the base metal. Where corrosion is not a serious problem, and where the operating temperatures are not too high, ordinary carbon steel has served very well. But, when corrosion is serious, and/or when the temperatures are either very high or very low, it is necessary to use some form of alloy steel to give satisfactory service. A great deal of credit is due to the members of the Boiler Code Committee and also to the members of the Joint A.P.I.-A.S.M.E. Committee, who have formulated codes that insure the safety of the

Jan 1, 1935

By R. K. Hopkins

For a great many years fusion welding has been used in and around petroleum refineries, but it is only within six or seven years that the more important pressure vessels have been constructed by this process, because before that time the properties of fusion welds would not withstand such rigorous service. Since the adoption of fusion welding for the construction of this equipment, the refiner has required pressure vessels suitable for operation over a very wide range of conditions. On the one hand, vessels must operate at extremely high temperatures, in the range of 950" to 1000° F., and on the other vessels must be suitable for operation at sub-zero temperatures down as low as —75" F. Also, vessels are required suitable for operation at pressures upwards of 1000 lb. per sq. in., and as low as a 29-in. vacuum. In addition, vessels are required to withstand the attack of very corrosive mediums. It has been a rather difficult task for the fabricator to meet all of these requirements, but as a result of the extensive research carried on by steel manufacturers and several fabricators of class I vessels, practically all of these demands have been met. In order to meet the refiners' requirements for this wide range of conditions, the fabricator has worked closely with the metallurgist. This has enabled him to choose the proper base metal for each service condition, but it has been the fabricator's problem to develop a welding rod and welding technique, as well as a heat-treatment, that would produce in the welded vessel characteristics in and around the weld comparable to those in the base metal. Where corrosion is not a serious problem, and where the operating temperatures are not too high, ordinary carbon steel has served very well. But, when corrosion is serious, and/or when the temperatures are either very high or very low, it is necessary to use some form of alloy steel to give satisfactory service. A great deal of credit is due to the members of the Boiler Code Committee and also to the members of the Joint A.P.I.-A.S.M.E. Committee, who have formulated codes that insure the safety of the

Jan 1, 1935

By K. B. Nowels

DATA pertaining to pipe line flow for both oil and gas in horizontal or nearly horizontal pipe lines are both extensive and accurate. However, the pipe formulas used to determine pressure drop for flowing fluids (liquids and gases) under conditions of horizontal flow are not generally applicable to flowing oil and/or gas wells. Except for some data developed in small laboratory set-ups, little or no information was available concerning flow of oil and gas mixtures in vertical pipes, when, in 1928, the writer began the development of a method for computing pressure drops in the pipes of flowing oil wells, as outlined in this paper. In 1929, Uren1 presented some findings based on laboratory experi-ments in which vertical flow of an extremely heavy crude oil was induced, by means of air through a 2-in. pipe, 41 ft. long. The friction factors derived from the experiment, as well as values for pressure drop per 100 ft., are not believed satisfactory in their application to flow problems in the field. Versluys,2 also in 1929, presented a mathematical development of the theory of flowing oil wells, and in 1930, gave a companion paper3 setting forth some principles governing the choice of length and diameter of tubing in oil wells. Since the termination of the study presented in this paper, another. valuable contribution pertaining to the problem, of vertical flow was made by Moore and Wilde.4 Although there were writings dealing with the principles of the gas-lift, a search of the available literature indicated that specific information on vertical flow was lacking with the exception of the writings of Uren, Versluys, and Moore and Wilde, to which reference .has been made.

Jan 1, 1932

By Bailey Willis, George Otis Smith

I. Summary of General Features. Location.—The Clealum iron-ore deposits occur on Clealum river, a tributary of the Yakima river; in the eastern spurs of the Cascade range, Washington.† Mount Stuart, 9470 feet in altitude, is a dominant peak of the district, which will therefore be referred to as the Mount Stuart district. By way of the valley and cañon of the Clealum, the ores are 18 miles from Roslyn, the colliery-town, which is reached by a short branch from the Northern Pacific Railroad. Where they occur the valley has an elevation of 2900 to 8000 feet above sea; that of the end of the branch railroad at Ronald is 2345 feet. The grade of the valley from near Ronald to the junction of the Clealum and Salmon Lasac rivers, 144 miles, is 20 feet per mile; thence to the iron-ores it is 130 feet per mile, through a cañon 241/2 miles long. Abreast of the deposits the western wall of the valley is formed by precipices of sandstone; the eastern slope is comparatively gentle, being cut in easily eroded

Jan 1, 1901

By Barry K. McMahon

The fundamental problem in rock mechanics is accounting for the discontinuous and anisotropic nature of the jointed rock mass. It is this problem that makes rock mechanics distinct from the mechanics of steel, glass, or concrete. Existing mathematical models explain much of the behavior of rock cores in the laboratory but, in civil engineering at least, the rocks that matter are the ones that are already broken. On the other hand, the basically descriptive methods now used in engineering geology do not lend themselves easily to mathematical analysis. A set of indices of geological properties related to the strength and deformation characteristics of jointed rock is needed. Like the index properties used in soil mechanics these will probably not have precise mathematical meaning, but once correlations are established with large scale tests they can form a basis for the transfer of test results, obtained in one area under one set of conditions, to the prediction of rock behavior in another area under another set of conditions. Indices of rock properties are even more important in rock mechanics than in soil mechanics as the cost of testing is much higher. To be useful, these indices must be easily and quickly measured and give reproducible results when measurements are made by different people. In this paper the word "joint" means all naturally occurring rock fractures with less than 3 in. of clay or other soft coating material. EXISTING INDICES OF ROCK PROPERTIES A comprehensive review of indices of rock properties for intact rock is given by Deere and Miller.' They provide charts ". . . for estimating the strength or modulus properties for intact rock from the numerical indices obtained by either the Schmidt hammer, the Shore Scleroscope,

Jan 1, 1968

By Mason K. Banks

A process has been developed which produces spodumene concentrates assaying 6.0 pct Li2O and 0.45 pct Fe2O3, with 70 to 75 pct recovery of spodumene. Two flotation separations are required: the simultaneous removal of mica, feldspar, and quartz as a froth product using a cationic collector, and the subsequent removal of iron-bearing minerals as a froth product while spodumene is depressed as a tailing. SINCE the close of World War II there have been numerous developments resulting in the increased use of lithium by industry. Notable among these has been the development of an industrial lubricant, based on lithium stearate, which is fluid at low temperatures, stable at high temperature, and insoluble in water. A new bleaching agent, lithium hypo-chlorite, has also been developed recently.' Other well-known uses are listed below: 1—Lithium oxide in ceramics reduces firing time, lowers melting temperatures, lowers thermal expansion, raises refractive index, and improves chemical resistivity. 2—Lithium carbonate and lithium strontium nitrate are used in pyrotechnics for their brilliant red color.' 3—Lithium chlorides and fluorides are used as fluxes for welding aluminum and magnesium.' 4—The affinity of lithium for nitrogen is the basis for a process used in purifying helium." 5— Lithium chlorides and bromides are used in air conditioning for their powers to absorb organic amines, ammonia, and smoke.6-—Lithium hydride has been used as a source of hydrogen to inflate life rafts and balloons used by the Air Forces and Navy.' 7— Lithium metal and lithium hydride are useful in the atomic energy program in connection with the production of the isotopes of hydrogen." During the 1942-45 period of World War 11, Solvay Process Co. operated a flotation plant with a daily capacity of 300 tons of ore for the production of spodumene concentrate near Kings Mountain, North Carolina. The operation was shut down upon reduction of wartime demand for lithium chemicals, and until recently there has been no production from the Carolinas. In April 1950 an investigation of the problem of spodumene flotation from North Carolina ores was begun at North Carolina State College Minerals Research Laboratory at Asheville, N. C. This laboratory, operating under the combined auspices of North Carolina State College, North Carolina Department of Conservation and Development, and the Tennessee Valley Authority, undertook the spodumene project at the request of Foote Mineral Co. of Philadelphia. The work, involving a period of 15 months of intensive batch and pilot plant investigation, was completed in June 1951 and resulted in development of a process for concentration of spodumene by flotation which has been hereto unrecorded in the literature. A similar approach has been used before on iron, ilmenite, and other minerals, but the literature shows no record of its having been applied to spodumene. Parts of the process are now being used on a commercial scale at the Foote Mineral Co. plant near Kings Mountain, N. C., which has been in production since July 1951. It is the purpose of this paper to describe some of the results of the investigation. The Orebodies Spodumene-bearing pegmatites occur in a narrow belt 24.5 miles long and 1.8 miles wide extending southwestward from Lincolnton to Grover, N. C. According to statements judged to be conservative, the tin-spodumene belt of the Carolinas contains an estimated 4,300,000 tons of pegmatite ore averaging 15 pct spodumene. This amounts to "a reserve of at least 650,000 tons of spodumene (more than 20,000 tons of metallic lithium) to a depth of 100 ft."' This figure includes only bodies having an average thickness of 35 ft and length of 550 ft. There are hundreds of pegmatites in the belt, many of which are less than 10 ft wide. The largest pegmatite in the area has a maximum thickness of 395 ft and maximum length of 3250 ft.' These larger pegmatites are composed principally

Jan 1, 1954

By George Mixter

MINING, in contrast to manufacturing, deals with a wasting asset. That which is taken out of the ground is gone, the property is depleted to that extent, and will eventually become exhausted of profitable ore. So the life of a mining company is dependent upon the ability of its management to develop improved methods to permit extraction at a profit of the lower-grade ores which remain, to extend by intelligent exploration the limits of its known ore bodies, and to find and acquire new properties to take the place of those that, for one reason or another, are no longer operated. Its history is a story of constant change, of the working out of properties here and the acquisition and development of properties there, to maintain the vitality of the whole. It is a story of estimating with the tools and the knowledge available the location and extent of hidden ore bodies and of devising the means of extracting

Jan 1, 1948

By H. K. Shearer

There were no important developments in the oil and gas industry in South Arkansas during 1935. Oil production, totaling 11,138,340 bbl., continued the decline that has been normal since 1925, but the decline from 1934 was only 278,600 bbl., or 2.5 per cent. The principal decline was in the Smackover field, while only the Champagnolle and Garland City fields showed notable increases. More wells were drilled than in any recent year, with a total of 123 completions. There were 44 oil wells, with a total reported initial daily production of 10,013 bbl., or an average of 227 bbl. per well. Two small gas wells were completed in Union County, where the gas is used locally for pumping and field operations. There were 77 dry holes, of which 28 were in or near oil fields and 49 were wildcats. Active drilling oper-at'ions declined from 65 at the beginning of 1935 to 41 at the end. Most of the drilling was done during the first part of the year, espr-chially (luring the flurry caused by the discovery late in 1934 of the "Taylor" sand production in the Champagnolle field, but the producing area was soon outlined. In November, 1935, the J. E. Crosbie, Inc., NO. 1 Sullivant in sec. 12, 17s. 14W., producing 560 bbl. per day at 3175 ft., opened a new sand lens in the eastern part of the field. The Camden "oil field," discovered in the last week of 1934, remained a one-well field, although four offset tests were drilled, besides a number of others in the immediate vicinity. Several interesting deep tests were drilled during the year, which added a great deal to the general knowledge of the subsurface formations and the structure of south Arkansas, but were not particularly encouraging as to prospects for the very deep production. First, the H. L. Hunt, No. 15 E. F. Gregory well in sec. 10, 17S., 14\W., in the Champagnolle field, was drilled to a depth of 6911 ft. It pene-trated red beds for 2982 ft., from 2943 to 5925 ft., mostly if riot entirely of Lower Cretaceous age. There was some anhydrite in the last 135 ft. of red beds. This was followed by 890 ft. of limestone, probahly Permian, and the rock salt was struck at 6815 ft. The salt is now generally conceded to be of Permian age. Finding salt in this well strongly indicates

Jan 1, 1936

By H. K. Shearer

There were no important developments in the oil and gas industry in South Arkansas during 1935. Oil production, totaling 11,138,340 bbl., continued the decline that has been normal since 1925, but the decline from 1934 was only 278,600 bbl., or 2.5 per cent. The principal decline was in the Smackover field, while only the Champagnolle and Garland City fields showed notable increases. More wells were drilled than in any recent year, with a total of 123 completions. There were 44 oil wells, with a total reported initial daily production of 10,013 bbl., or an average of 227 bbl. per well. Two small gas wells were completed in Union County, where the gas is used locally for pumping and field operations. There were 77 dry holes, of which 28 were in or near oil fields and 49 were wildcats. Active drilling oper-at'ions declined from 65 at the beginning of 1935 to 41 at the end. Most of the drilling was done during the first part of the year, espr-chially (luring the flurry caused by the discovery late in 1934 of the "Taylor" sand production in the Champagnolle field, but the producing area was soon outlined. In November, 1935, the J. E. Crosbie, Inc., NO. 1 Sullivant in sec. 12, 17s. 14W., producing 560 bbl. per day at 3175 ft., opened a new sand lens in the eastern part of the field. The Camden "oil field," discovered in the last week of 1934, remained a one-well field, although four offset tests were drilled, besides a number of others in the immediate vicinity. Several interesting deep tests were drilled during the year, which added a great deal to the general knowledge of the subsurface formations and the structure of south Arkansas, but were not particularly encouraging as to prospects for the very deep production. First, the H. L. Hunt, No. 15 E. F. Gregory well in sec. 10, 17S., 14\W., in the Champagnolle field, was drilled to a depth of 6911 ft. It pene-trated red beds for 2982 ft., from 2943 to 5925 ft., mostly if riot entirely of Lower Cretaceous age. There was some anhydrite in the last 135 ft. of red beds. This was followed by 890 ft. of limestone, probahly Permian, and the rock salt was struck at 6815 ft. The salt is now generally conceded to be of Permian age. Finding salt in this well strongly indicates

Jan 1, 1936

By Ajoy K. Ghose

INTRODUCTION Longwall mining made its debut in Indian coal mining scene around 1900. Despite this headstart, the application of the method has been slow and halting. Currently, there are some 16 operating longwall faces only in different Indian coalfields contributing to perhaps less than 3 percent of the total underground coal production. Ambitious plans for expansion of longwall mining notwithstanding, apprehensions on the cavability of Indian coalmeasure roof rocks and some unsavoury experiences with face collapses in caved longwalla have impeded wider adoption of the technique. Between 1960 and 1983, some 41 caved longwall faces were worked in Jharia, Raniganj, Karanpura and Korba Coalfields in India, of which 6 faces reportedly had collapsed(1). The first powered support longwall face was started in August 1978 at Monidih colliery which marked a major step forward in the introduction of advanced technological system in Indian coal industry. This paper attempts to analyse critically the experiences with longwall ground control in caved longwall faces in India. Experiences from powered support faces at Monidih, Dhemomain and Pathakhera are synthesized to provide an appraisal of the present status of caved longwall faces under the Indian coalmeasure roofs, which thus far have been characterised as “massive”. The geotechnical site factors at the powered support faces are evaluated and conclusions drawn on the pre-assessment of caving characteristics and support resistance required at the faces.

Jan 1, 1984

By K. C. McCutcheson

To a very large extent the quality of a mild steel ingot is determined by the manner in which it is poured into the ingot mold and its behavior during the first few minutes after it has been poured. The formation of the solid rim of metal around the periphery of the mold, the effervescent action of the liquid steel within this solidified rim and the upward or downward movement of the metal level are indications of what is going on beneath the surface of the liquid metal, especially at the interface at which solidification occurs. Observation of this "rimming action" enables an experienced observer to predict the thickness of the sound skin of the ingot and the location and extent of cavities or "blowholes" caused by entrapment of gases. The control of rimming action at the hands of a skillful steel pourer is a vital part of the control of quality in mild steel sheet, and the behavior of the liquid steel during the rimming period is a useful criterion of the melting and refining practices employed in the open hearth. The behavior of rimming steel during solidification depends primarily upon the evolution of gases from the molten metal and it is therefore a problem of considerable interest to determine the nature and amount of the gases evolved. A number of attempts to determine either the amount or the analysis of the, evolved gases have been reported. Klinger,1 in 1925, analyzed the gases extracted from rimming, semikilled and killed steel ingots and found that the chief constituent of the rimming gas was carbon monoxide. The relatively large amounts of nitrogen reported in his first few samples may have been due to incomplete removal of air from the gas-collecting mechanism. McKune2 reported similar studies of rimming ingots from which surprisingly large proportions of nitrogen and hydrogen were evolved. Ameen and Willners3 determined both the amount and composition of gases extracted from unkilled ingots with the aid of diminished pressure. Their ingots weighed only 80 kg. (176 lb.) and apparently were solid within two or three. minutes, so that their

Jan 1, 1938

By L. R. Gremillion, G. H. McClellan

Chemical and mineralogical data on 25 apatitic phosphate ores of diverse origins from commerical deposits around the world were widely variable. From 14 to 18 chemical constituents of each sample were determined, and each sample contained four to ten mineral phases. Altogether there were 34 different mineral phases, many of which occurred in only one sample. Samples contained varieties of francolites, fluorapatites, and mixed hydroxyfluorapatites. The apatite compositions calculated from chemical data showed that certain types of substitutions were characteristic of different apatite varieties, but every variety had some degree of substitution of (CO3)2- for (PO4)3-, and the P205 contents of the apatites ranged from 35.1 %for a North Carolina apatite to 41.9% for a Missouri apatite. In a concentrate with a grade of 32% P2O5, the North Carolina sample should contain about 8.7% gangue and the Missouri sample about 23.7% gangue. To optimize the digestion process of a phosphate ore, it is necessary to consider the dissolution behaviors of different mineral phases during acidulation and their possible effects on chemical properties of a fertilizer intermediate. In the production of wet-process acids or superphosphates, acidulation of certain minerals may cause foaming and formation of sludge, filtration, corrosion, and handling problems.

Jan 1, 1982

By E. A. Gulbransen, J. W. Hickman

IN a previous paper1 the authors have investigated the structure of the oxide films formed on most of the metals that make up the alloys of this study. The metals were studied in order to provide basic information on the structures, both physical and chemical, of the oxide films and to determine how these structures are effected by the temperature, time of oxidation, and surface preparation. It was felt that an understanding of the physical and chemical structure as well as the stability of the oxide film might furnish clues as to the nature of the reaction process and the protective quality of the film. The oxidation of the metals was studied over the temperature range 300° to 700°C. except for copper, where the range selected was 100° to 500°C. The results of these studies were presented in graphical form as existence diagram, of the oxides on a time-temperature scale. For some of the metals the existence diagrams were simple and showed few chemical transitions, but there were numerous cases where the physical state of the oxide surface was a function of time and temperature. In general the physical state of the oxide surface changed with increasing temperature so as to increase the sharpness of the diffraction patterns and to cause orientation effects to be more pronounced. Deviations in lattice parameters from X-ray values were noted. In general these deviations were of positive nature and may be due to solid solution of the metal in the oxide lattice. This effect might be expected in thin oxide films. In a study of the oxidation of alloys containing two or more metals, there may arise the complicating factor of identification of the oxides formed. A thorough understanding of the oxides formed on the pure metals, therefore, was, essential before investigation of the oxidation of alloys. In this paper it is our purpose to present a study of the following problems: I The existence diagrams of various alloys. [2.] The effect of the structure of the [ying] metal on the existence diagram of Iron. 3. The effect of the percentage of chromium on the oxides formed on Fe-Cr alloys. 4. The relationships, if any, between the oxides formed and the protective quality of the oxides. The following alloys are included in this study: alloys of iron with body- centered cubic, face-centered cubic and other metals, 13 Cr-Fe, 18-8 stainless steel, K42B1 Nichrome V, Hipernik, Inconel, Stellite " 21," Refractaloy, Kovar, mild steel, a series of Cr-Fe alloys and a series of Co-Fe alloys. Since many of the commercial alloys in this list contain more than two metals, various complicating factors in the identification of the oxides formed may arise.

Jan 1, 1946

By H. W. Maynor, C. J. McHargue

DURING the course of an investigation of materials suitable for use as thermocouples at elevated temperatures by one of the authors, several nlolybdenum-rhenium alloys were prepared. Micrographs of an annealed alloy containing 25 pct Re (intended concentration; analysis not obtained) showed a number of twins, Fig. 1, suggesting a face-centered cubic structure. This note reports the structure and recrystallized wire texture of an alloy containing 25 wt pct Re. Alloys were prepared from 99.9 pct Mo (Fansteel Metallurgical Corp.) and rhenium obtained from the University of Tennessee (purity unreported). Powders were combined and briquetted at 56,000 psi and sintering was carried out at 2400°C for 5 hr in vacuum. Ingots so prepared were swaged at 982.2" to 1037.8oC into wires 0.036 in. diameter, a reduction in diameter of 85.6 pct. These wires were vacuum-annealed 1 hr at 2000°C. A North American Philips 114.59 mm powder camera and nickel-filtered copper radiation were used for structure determination. For the texture determination a Laue-type camera was used with zirconium-filtered molybdenum radiation and, because of the high background, aluminum foil was mounted next to the film. Exposures were taken with the wire perpendicular to the X-ray beam and tilted by 10". It was found that the X-ray pattern could be indexed on the basis of a face-centered cubic structure. Because of difficulties associated with obtaining a good X-ray pattern for this material, accurate parameter determinations were not made. An indicated parameter value of 3.70A was obtained. The X-ray data are given in Table I. The annealed wire texture was observed to be a sharp [111] texture. The spread about this fiber axis was k8" at the surface of the 0.036 in. wire. The annealed wire textures of aluminum have been reported as retention of the [Ill] deformation texture for anneals below 500°C and a new [1121 texture for anneals above 600°C.1 In copper wires, with a [Ill] plus [loo] deformation texture, results indicate a retention of this texture for annealing at lower temperatures and new components or the disappearance of components for annealing at higher temperatures.' The presence of the strong [I111 texture in the molybdenum-rhenium alloy after a 2000 °C anneal suggests that the deformation texture was the same. Acknowledgment The wires used in this study were prepared and heat-treated at the Institute for Atomic Research, and Ames Laboratory, Iowa State College, and the authors wish to express their thanks to the Institute for allowing the use of the material and permission to publish the results.

Jan 1, 1954

By K. P. Chong

Introduction One of the requirements of processing oil shale or other energy bearing rocks is to optimize particle sizes and permeability distributions in fragmentations as indicated by Hommert (1984). Basic to the understanding and planning of in situ fragmentation and ex situ mining of oil shale are the mechanical properties. During the past six years, an innovative and unique program was established by Chong et al. (1979, 1980a, 1980b, 1982a, 1982b) that developed an efficient methodology for standardized and simplified mechanical testing of the western oil shale. The experiments include precise, representative, and duplicable sample preparation; uniaxial static compression testing; "modified" split cylinder testing; uniaxial creep and relaxation testing under extended periods of time; dynamic testing with varying strain rates; and 3-D constitutive relationships. However, as far as the fracture mechanics is concerned, as Edl (1980) pointed out, there is still a lack of understanding "of the fundamental explosive rock breakage mechanisms," which "has necessitated extensive reliance on very costly empirical approaches." Fracture mechanics of rocks and oil shale (Costin, 1981; Schmidt, 1977; Abou-Sayed, 1977; and Barker, 1977) has been based on conventional fracture mechanics using regular notched samples with limited variations of oil yields and assuming the material to be isotropic and elastic (Kobayashi, 1975; Caddell, 1980). A cylindrical double cantilever beam (DCB) specimen with a "V" slot, known as a short rod specimen, has been used by Barker (1977) to determine fracture toughness of rock materials. The inherent geometric stability of the reinforced DCB specimen makes it suitable to be used with all brittle materials. Due to its remarkable stability for the initial crack growth, the DCB specimen can be used for dynamic fracture toughness testing as well. This specimen is more suitable for the evaluation of fracture toughness at high strain rates than most other fracture specimens. However, Barker's DCB specimen is not very well adaptable for short cores or layered rocks since the specimen contains numerous layers (say in a 100-mm (4-in.) long specimen), and the rock properties change from layer to layer. Schmidt (1977) studied the fracture mechanics of oil shale with two oil yields, using notched beams. Using several independent established testing methods, Costin (1981) pioneered the investigation of the static

Jan 1, 1986

By K. S. Benson

DEPLETION is a subject of vital importance to the mining industry. Yet, in spite of its importance, its significance is not generally understood. The purpose of this discussion is to clarify the main aspects of the subject from the viewpoint of a metal mine taxpayer. To define the term depletion, it is necessary to distinguish among its various uses. In the economic or geological sense, depletion means the exhaustion of a natural resource. A mineral deposit is a wasting asset and once exhausted is nonrenewable. Millions of years were needed to produce an ore deposit, which may be consumed in a few years and which cannot be replaced except by the discovery of new sources of supply. The wasting asset feature of the mining industry has a vital bearing on the impact of the Federal Income Tax Law on this industry. This is recognized in the law by the various provisions dealing with the depletion allowance, and in this sense the term depletion has an income tax meaning. Depletion from the tax viewpoint means the statutory deduction from gross income designed to permit the return to the taxpayer of the capital consumed in the production and sale of a natural resource. The mining enterprise realizes income on the extraction and sale of minerals and a portion of the income realized represents capital consumed. As the resource is exhausted, the mining enterprise approaches the end of its existence unless new sources of supply can be acquired. Depletion from the tax viewpoint is a creature of statute with limited meaning and application and, in essence, is a method for amortizing the value of the primary asset of a mining enterprise. An example can best illustrate the significance of depletion from the tax viewpoint. Compare a manufacturing concern with a mining company. In computing taxable income of a manufacturing concern, consideraion is given to the cost of producing such income, the principal costs being capital investment for plant and equipment, labor, and raw materials going into the products produced. A mining enterprise, on the other hand, is faced with a different problem because its principal asset is the natural resource which it is producing. In computing its taxable income, consideration is given also to its capital investment for plant and equipment and the cost of labor; but in addition, recognition must be given to the fact that a portion of the proceeds realized on the sale of mineral represents capital. Without such recognition, the mining company would be taxed not on income but on capital and income, and Congress has never intended that capital be taxed as income. Thus, when depletion allowable is referred to in the mining industry, it means the statutory deduction allowable in computing taxable income of a mining enterprise. For guidance the appropriate provisions of the Internal Revenue Code, Income Tax Regulations, and the judicial decisions interpreting and construing them must be examined. It is important to identify and distinguish three methods of determining the allowance for depletion: 1—Cost depletion, 2—Discovery depletion, and 3—Percentage depletion. The basic method is cost depletion and in addition some taxpayers may be entitled to use discovery depletion and other taxpayers may be entitled to use percentage depletion. Discovery depletion and percentage depletion, however, are mutually exclusive and if a taxpayer is entitled to percentage depletion, he is not entitled to discovery depletion. By statute, a metal mine taxpayer is entitled to use cost depletion or percentage depletion, whichever produces the highest deduction. Thus, discovery depletion is merely of academic interest to such taxpayers and to most others. Briefly and broadly speaking, these methods of determining depletion may be described as follows: 1—Cost Depletion: Under this method, the allowable deduction for depletion is based upon the cost of the particular deposit to the taxpayer, unless the deposit was owned prior to Mar. 1, 1913, in which case the taxpayer may use the fair market value of the deposit on that date or actual cost, whichever is higher. This method is sometimes described as basis depletion or adjusted basis depletion, but in this discussion it will be referred to as cost depletion. 2—Discovery Depletion: Under this method, the allowable deduction for depletion is based on the fair market value of the deposit at the date of discovery or within 30 days thereafter and was originally designed to take into account deposits discovered subsequent to Feb. 28, 1913. 3—Percentage Depletion: Under this method, the allowable deduction for depletion is based on a specified percentage of the income realized during the taxable year from a particular property. As stated, the concept of depletion is based upon the exhaustion of a natural resource as distinguished, for example, from the concept of depreciation based on the exhaustion of property used in trade or business. From the tax viewpoint, depletion first became important in the administration of the Corporation Tax Act of 1909, which provided for an excise tax on net income. As soon as this act went into effect, mining taxpayers attempted to claim a deduction for depletion in computing net income although there was no specific mention of a deduction for depletion in the statute. The courts in these cases uniformly held that the statute did not permit an allowance for depletion in computing net income and also held that the provision permitting a reasonable allowance for depreciation did not include depletion. These early cases are quite significant because they establish the principle that the

Jan 1, 1952

By James K. Stanley

Preferred orientation, particularly in irons and low-carbon steel, is a phenomenon that is both of considerable importance and theoretical interest. At times it is a liability and at other times an asset. In deep-drawing operations, preferred orientation is extremely undesirable because it necessitates trimming operations and increases scrap loss. Furthermore, oriented metals are likely to crack more easily than randomly oriented material because the forming of symmetrical and unsymmetrical shapes out of preferentially oriented metals and alloys increases the probability of rupture in regions of high stress, owing to differential ductility.' In the electrical industry, on the other hand, preferentially oriented silicon irons are in demand for transformer application because of the improved magnetic permeabilities in the rolling direction.2 This phenomenon of preferred orientation in soft magnetic materials has been responsible for the tremendous improvement in transformer design and construction in recent years. Directional properties in metals have received a great deal of attention in the metallurnical -literature,3-9 in which much of the information reported about orientation has been obtained by conventional methods, mechanicai properties and X-rays. A wealth of data has been obtained and often at a great expenditure of time. The recent introduction of the magnetic torque measurements on ferromagnetic materials provides a very simple and rapid method of evaluating orientation. The judicious use of the method can supply important information, but it should be borne in mind that such studies must be supplemented by X-rays, optical methods,10 and etch and pressure figures" to get a rational understanding of the orientation phenomena. No claims are made that the magnetic torque of evaluating orientation will reveal the behavior of the metal in deep drawing. For this purpose the accepted tests for deep-drawing quality must be used. For a good drawing stock, which must have low impurities, desirable grain size, ductility, strength, hardness, good surface, random orientation, and good recrystallization behavior, it cannot be expected that any simple test will be satisfactory for appraising all the factors. The only factor on which the magnetic method can be used is orientation, which is, of course, of considerable importance. When directionality can cause a 10 to 15 per cent change in tensile strength and a IOO to 300 per cent change in tear length,12 it goes without saying that a reliable as well as rapid method for detecting these changes would be desirable. There are certain inherent advantages in testing orientation by the torque method: The method is rapid with the proper type of equipment; no elaborate preparation of specimens is required—it is only necessary to punch or machine a I-in. disk of the sheet material and insert it into the testing device.

Jan 1, 1944

By James K. Stanley

Preferred orientation, particularly in irons and low-carbon steel, is a phenomenon that is both of considerable importance and theoretical interest. At times it is a liability and at other times an asset. In deep-drawing operations, preferred orientation is extremely undesirable because it necessitates trimming operations and increases scrap loss. Furthermore, oriented metals are likely to crack more easily than randomly oriented material because the forming of symmetrical and unsymmetrical shapes out of preferentially oriented metals and alloys increases the probability of rupture in regions of high stress, owing to differential ductility.' In the electrical industry, on the other hand, preferentially oriented silicon irons are in demand for transformer application because of the improved magnetic permeabilities in the rolling direction.2 This phenomenon of preferred orientation in soft magnetic materials has been responsible for the tremendous improvement in transformer design and construction in recent years. Directional properties in metals have received a great deal of attention in the metallurnical -literature,3-9 in which much of the information reported about orientation has been obtained by conventional methods, mechanicai properties and X-rays. A wealth of data has been obtained and often at a great expenditure of time. The recent introduction of the magnetic torque measurements on ferromagnetic materials provides a very simple and rapid method of evaluating orientation. The judicious use of the method can supply important information, but it should be borne in mind that such studies must be supplemented by X-rays, optical methods,10 and etch and pressure figures" to get a rational understanding of the orientation phenomena. No claims are made that the magnetic torque of evaluating orientation will reveal the behavior of the metal in deep drawing. For this purpose the accepted tests for deep-drawing quality must be used. For a good drawing stock, which must have low impurities, desirable grain size, ductility, strength, hardness, good surface, random orientation, and good recrystallization behavior, it cannot be expected that any simple test will be satisfactory for appraising all the factors. The only factor on which the magnetic method can be used is orientation, which is, of course, of considerable importance. When directionality can cause a 10 to 15 per cent change in tensile strength and a IOO to 300 per cent change in tear length,12 it goes without saying that a reliable as well as rapid method for detecting these changes would be desirable. There are certain inherent advantages in testing orientation by the torque method: The method is rapid with the proper type of equipment; no elaborate preparation of specimens is required—it is only necessary to punch or machine a I-in. disk of the sheet material and insert it into the testing device.

Jan 1, 1944

By V. M. Karve, K. K. Majundar, K. V. Viswanathan, J. Y. Somnay

The effect of calcium, magnesium, iron (both ferrous and ferric) and aluminum ions, which are commonly encountered in a typical beryl ore, was studied in the flotation of pure beryl, soda-feldspar and quartz. The vacuumatic flotation technique was employed. With sodium oleate as collector and in the absence of any activator, beryl floated in a pH range of 3 to 7.5, whereas feldspar and quartz did not float at any pH up to 11.5. The pH range of flotation increased in the presence of the ions studied. With calcium and magnesium ions beryl floated from 3 to 11.5 pH and beyond, soda-feldspar floated beyond pH 6 and quartz floated beyond pH 8. Ferrous ion activation was found to be similar to that of calcium and magnesium. Activation by ferric and aluminium ions was found to be complex and the lower and upper critical pH for all the three minerals was around 2 and 10 respectively. These studies indicated the possibility of separation of beryl from feldspar and quartz even in the presence of calcium, magnesium and ferrous ions between pH 4 and 6. Flotation tests on a mixed feed of pure minerals in a 10 g cell revealed that beryl can be selectively floated from feldspar and quartz if ferric ion is reduced to ferrous state or if it is complexed. Beryl occurs mostly in pegmatites, and hence is associated with feldspar, quartz and micas and small amounts of other minerals such as apatite and tourmaline. The separation of beryl from these minerals is difficult because all the silicates accompanying beryl have more or less the same physical properties. Specific gravities of beryl, feldspar and quartz are 2.70, 2.56 and 2.66 respectively. Electrostatic separation has been suggested but no work has been reported. ' The adsorption of sodium tri-decylate tagged with Cl4 on beryl, feldspar and quartz reveal similarity in surface properties. Much work has been reported on the flotation of beryl from ores, either directly or indirectly as a by-product, but little is known about the fundamental aspects of beryl flotation. Kennedy and O'Meara3 laid emphasis on prior cleaning of the mineral surfaces with HF. Mica is removed first by flotation of beryl with oleic acid, around neutral pH. Runke4 introduced calcium hypochlorite conditioning in a final separation stage for activating beryl in a mixed beryl-feldspar concentrate, and after washing to remove the hypochlorite, floated beryl with petroleum sulphonate. The Snedden and Gibbs5 procedure is somewhat similar to that of Kennedy and O'Meara. Emulsified oleic acid is used as collector. Recently Fuerstenau and Bhappu6 studied the flotation of beryl, feldspar and quartz with petroleum sulfonate in the presence of activators and stressed the importance of iron in the flotation of beryl. From the studies conducted in this laboratory, it was found that feldspar and quartz as such do not float with sodium oleate, but in practice selective flotation of beryl from feldspar and quartz in an ore is found to be impossible with sodium oleate as collector. A glance at the chemical analysis of typical beryl ore indicates the presence of several ions like Ca ++, Mg++, Al + + + and Fe+++ in abundance and Ti++++ and Mn++ in traces. Hence, in an attempt to explain the behaviour of feldspar in the beryl flotation, the effect of Ca++, Mg++, Al+++ and Fe+++, which are known as gangue mineral activators7'8 has been investigated. Materials and Methods: Lumps of beryl ore (hand picked) were boiled with 10% sodium hydroxide and washed with distilled water. They were further boiled many times with 10% hydrochloric acid till no positive test for iron was obtained with ammonium thio cyanate. This was followed by thorough flushing with double distilled water. The lumps were crushed in a porcelain mortar and pestle under water. The minus 65 + 100 mesh fraction was used for testing and was always stored under distilled water. Pure feldspar and quartz were similarly prepared and the minus 65 + 100 mesh fractions collected. Inorganic ions tried as activators were ca++, Mg++ , Fe++, Fe ++ and A1 +++ . Calcium nitrate, magnesium chloride, ferrous ammonium sulfate, ferric ammonium sulfate and aluminum nitrate of G.R.E. Merck grade were used. B.D.H. technical grade sodium oleate was used as a collector. The vacuumatic flotation technique developed by Schuhmann and Prakash was used for studying the effect of pH on flotability. 7 The indications given by this work were confirmed by using 10 g miniature cell.'

Jan 1, 1965

By Edward Thomas

THE late George S. Rice was active in the investigation of bumps, particularly in the last ten years of his career as chief mining engineer of the U. S. Bureau of Mines. Since most of his investigation was carried out in Great Britain, continental Europe, and-to a lesser extent-Canada, his thinking on prevention was influenced considerably by the experience of those countries. It is not surprising, therefore, that when he was called upon a few years before his retirement to investigate bumps in the U. S. and suggest ways to prevent them, he turned to longwall mining. A longwall method had been most successful in combating the bump hazard in mining coal under deep cover, especially in Great Britain, but the prevailing method there at the time was advancing longwall mining, which he knew was uneconomical under U. S. mining conditions. For this reason he proposed a modified retreating longwall system that he believed included the best features of the advancing method. As brought out by Rice,1 if the cover is 2000 ft and 50 pct of the coal is extracted, the static load on the remaining pillars will be about 4000 psi, which exceeds the ultimate crushing strength2 in most instances. If the pillar coal is overloaded before a pillar line is established, then the abutment zone preceding a line of extraction is no place to split pillars or extract them by any method other than an open-end system. Rice therefore advocated open-end mining, preferably by longwall, but he was willing to compromise with long-face mining if the longwall method was not acceptable.

Jan 8, 1958