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By AIME AIME

COUNCIL PRESIDENT OF THE COUNCIL. CHARLES KIRCHHOFF NEW YORK, N. Y. (Term expires February, 1912.) VICE-PRESIDENTS OF THE COUNCIL. BENJAMIN B. LAWRENCE NEW YORK, N. Y. JOSEPH W. RICHARDS SOUTH BETHLEHEM, PA. ALBERT SAUVEUR CAMBRIDGE, MASS. (Term expires February, 1912.) S. B. CHRISTY BERKELEY, CAL. W. A. LATHROP PHILADELPHIA, PA. GARDNER F. WILLIAMS WASHINGTON, D. C. (Term expires February, 1913.)

Oct 1, 1911

By John F. Blandy

Every new mining district has had its own peculiar experiences in inventing and experimenting upon new methods for the various operations of mining, and more particularly in the processes of crushing and dressing ores. As a matter of course, during this period many old things have been reinvented, patented, and cast aside, there to remain until at a future day other geniuses shall bring them forth again as new. In this respect the Copper Region of Michigan has not been behind other mining centres, and probably in no other part of the country has more money been expended in devising new machines and improvements upon old ones for the crushing of the rock. The appliances for washing the sand have not been so varied, simply for the reason that, having but one mineral, or rather metal, of high specific gravity to separate from rock material which varies but little in its character in any one mine, it requires much less care than is necessary in most mining centres of the world. At the beginning of operations in that district most of the work was in the control of Cornish miners, who introduced the simplest of Cornish mills, namely, wooden stem pestles, with wooden shafts and cams. These were well suited to the small mines, and particularly to the limited means of transporting more expensive machinery. As these facilities improved, they were enabled to change to iron, and to vary their patterns of rods, shafts, cams, and mortars. The most approved pattern, finally obtained, is the square or round stem, with collar adjustable by means of keys. In its present form it is a bar of cold rolled shafting, an eye in the top, an adjustable collar with key-plate and keys, the head and a shoe of chilled iron. The stem is fitted into the head by a slight taper. The battery has heretofore been of wood, lined with chilled cast plates, and bed-plate of the same, but within the past year the California pattern has been introduced. The screens are of sheet-steel, drilled with 16 holes to the inch. During this period of trial and gradual improvement in the pestle stamps, in the years 1855-6, the Ball steam-stamps were introduced, and after years of labor and expense, have been made the most efficient and powerful machines ever yet used for the purpose. It is ostensibly the Nasmyth steam-hammer, and yet the

By AIME AIME

COUNCIL.* PRESIDENT OF THE COUNCIL. D. W. BRUNTON DENVER, COLO. (Term expires February, 1910.) VICE-PRESIDENTS OF THE COUNCIL. J. PARKE CHANNING NEW YORK, N. Y. FREDERICK W. DENTON PAINESDALE, MICH. JOHN B. FARISH DENVER, COLO. (Term expires February, 1910.) W. C. RALSTON SAN FRANCISCO, CAL. W. L. SAUNDERS NEW YORK, N. Y. H. V. WINCHELL ST. PAUL, MINN. (Term expires February, 1911.)

Mar 1, 1909

By R. Adair, W. R. Hudspeth, W. T. McDaniel

A NEW method for concentrating the flake mica either from present washing plant tailings or from new feed has been developed. In this paper, flake mica refers to that which occurs in weathered granites, alaskites, pegmatites, and schists in a form too fine to be considered sheet mica. It ranges in size from 1 in. or more down to 200-mesh or finer and occurs with kaolin, quartz, and partially kaolinized feldspar. Scrap mica, a term often used indiscriminately to describe everything other than sheet mica, will be used to denote the waste product from sheet mica mines and fabricating plants. Both flake and scrap mica are used in the mica grinding plants to produce wet-ground or dry-ground mica, although some flake mica recovered from clay mining operations is fine enough to be marketed without grinding.

Jan 3, 1951

By AIME AIME

COUNCIL.* PRESIDENT OF THE COUNCIL. D. W. BRUNTON DENVER, COLO. (Term expires February, 1910.) VICE-PRESIDENTS OF THE COUNCIL. J. PARKE CHANNING NEW YORK, N. Y. FREDERICK W. DENTON PAINESDALE, MICH. JOHN B. FARISH DENVER, COLO. (Term expires February, 1910.) W. C. RALSTON..: SAN FRANCISCO, CAL. W. L. SAUNDERS NEW YORK, N. Y. H. V. WINCHELL ST. PAUL, MINN. (Term expires February, 1911.)

Jun 1, 1909

By P. W. Bakarian, John C. McDonald

Three magnesium alloys were processed in various ways to exhibit a wide variation in the ratios of yield strength and tensile strength in the rolling direction compared to the cross-rolling direction. Basal-plane pole figures were prepared from several specimens. A fair correlation was observed between the property ratios and the ratio of percent of poles oriented in the cross-direction quadrants compared to the percent oriented in the rolling-direction quadrants of the pole figures. THE modes by which magnesium crystals deform are such as to lead to marked preferred orientations in all forms of wrought products. The effect of the active modes at room temperature, coupled with these orientations, is often to produce a lower compressive yield stress compared to the tensile yield stress. The phenomenon is due to easy twinning in compression, and has been well-related to the preferred orientations as described by basal-plane pole figures of the hcp magnesium single crystal. The literature contains some information on the variation with test direction of the tensile properties of sheet, but no quantitative relationship to the observed pole figures has been established. These effects have been reviewed in the few com- prehensive treatises in English which have been written on magnesium technology and metallurgy.1°3 Roberts presents several pole figures, but no tensile-property data in the plane of the sheet. Raynor has no pole figures, but quotes Frommer's4 results. The information in Beck's compendium more or less parallels the results of Jones and powell.5 In both a Mg + 1.5 Mn alloy and a Mg + 4.6 A1 alloy, cold rolling was found not to change the general situation of higher properties in the cross-rolling direction,* than in the rolling direction. Thomas'6 X-ray studies of Jones and Powell's specimens did not permit correlation of properties and preferred orientation. Ansel and Betterton7 report tensile and compressive properties on three other alloys as a function of degree of cold rolling, plus a recrystallizing anneal. As rolled, there was a change in anisotropy with degree of reduction, but all alloys were reasonably isotropic in tension when annealed. X-ray diffraction photograms illustrated the kinds of orientations present, but were not correlated with the properties. Bakarian8 has described a method of determining quantitatively a preferred orientation, and illustrated the method by applying it to pure magnesium and two of its alloys. This method was used in the present work as a basis for correlating the strength properties with the texture.

Jan 1, 1965

By B. Haimson, C. Fairhurst

A criterion is Proposed for the initiation of vertical hydraulic fracturing taking into consideration the three stress fields around the wellbore. These fields arise from (1) nonhydrostatic regional stresses in earth, (2) the difference between the fluid pressure in the wellbore and the formation fluid pressure and (3) the radial fluid flow through porous rock from the wellbore into the formation due to this pressure difference. The wellbore fluid pressure required to initiate a fracture (assuming elastic rock and a smooth wellbore wall) is a function of the porous elastic constants of the rock, the two unequal horizontal principal regional stresses, the tensile strength of the rock and the formation fluid pressure. A constant injection rate will extend the fracture to a point where equilibrium is reached and then, to keep the fracture open, the pressure required is a function of the porous elastic constants of the rock, the component of the regional stress normal to the plane of the fracture, the formation fluid pressure and the dimensions of the crack. The same expression may also be used to estimate the vertical fracture width, provided all other variables are known. The derived equations for the initiation and extension pressures in vertical fracturing may be employed to solve for the two horizontal, regional, principal stresses in the rock. INTRODUCTION Well stimulation by hydraulic fracturing is a common practice today in the petroleum industry. However, this stimulation process is not a guaranteed success; hence, the deep interest shown by the petroleum companies in better understanding the mechanism that brings about rock fracturing, fracture extension and productivity increase. Geologists and mining people became interested in hydraulic fracturing from a different point of view: the method may possibly be employed to determine the magnitude and direction of the principal stresses of great depth. Numerous articles in past years have dealt with the theory of hydraulic fracturing, but they all seem to underestimate the effect of stresses around the wellbore due to penetration of some of the injected fluid into the porous formation.1-4 Excellent papers on stresses in porous materials due to fluid flow have been published5,6 but no real attempt has been made to show the effect of these stresses in the form of a more complete criterion for vertical hydraulic fracturing initiation and extension. This paper is such an attempt. ASSUMPTIONS It is assumed that rock in the oil-bearing formation is elastic, porous, isotropic and homogeneous. The formation is under a nonhydrostatic state of regional stress with one of the principal regional stresses acting parallel to the vertical axis of the wellbore. This assumption is justified in areas where rock formations do not dip at steep angles and where the surface of the earth is relatively flat. This vertical principal regional stress equals the pressure of the overlying rock, i.e., S33 = —pD, where S33 is the total vertical principal stress (positive for tension), p is average density of the overlying material and D is the depth of the point where S33 is calculated. The wellbore wall in the formation is considered to be smooth and circular in cross-section. The fluid flow through the porous elastic rock obeys Darcy's law. The whole medium is looked upon as an infinitely long cylinder with its axis along the axis of the wellbore. The radius of the cylinder is also very large. Over the range of depth at which the oil-bearing formation occurs, it will be assumed that any horizontal cross-section of the cylinder is subjected to the same stress distribution, and likewise that it will deform in the same manner. STATE OF STRESS PRIOR TO DRILLING OF WELLBORE At a depth D from the earth surface within the oil-bearing strata, it is assumed that the following are 1References given at end of paper.

By H. C. Chang, N. J. Grant

Creep of very coarse grained, high purity aluminum was studied at 400° to 1100°F with an initial stress range of 50 to 1200 psi. The process of boundary sliding and migration was studied. The driving force of boundary migration under creep conditions is shown to be a combination of strain energy migrationand surface energy. A theory is presented regarding the strainenergyrole the grain boundaries play under creep conditions. From this thetheory intercrystalline failure of commercial alloys can be explained. Also from this theory an optimum grain size should exist for good high temperature properties of high purity materials. IN the investigation of the creep of very coarse grained, high purity aluminum previously reported,' the cyclic nature of the process of grain boundary sliding and migration has been established by microscopic observation of the actual creep process as well as metallographically. It was also substantiated by measuring localized strains across the grain boundaries. In addition, it was shown how extensive subgrain and fold formation may result from boundary sliding and how the slid grain boundary may become sharply wavy as a result of subgrain formation. Since the publication of those results, additional information on the process of grain boundary sliding and migration has been obtained. It is the purpose of this paper to report on the direction and driving force of boundary sliding and migration, the effect of grain size, and the effect of temperature. Finally the effect of decreasing purity (alloys 2s and 3s) on the process of boundary sliding and migration is noted. From these results, an explanation is presented for the intercrystalline failure of alloys under creep conditions. The effects of grain size on the creep properties of impure and high purity materials are discussed in the same light. The experimental procedures and technique have been presented elsewhere.' It is only necessary to state how the 2s and 3s aluminum specimens are prepared. Machined specimens were first annealed at 600°F for about 12 hr. In order to produce a large grain size the specimens were then stretched 3 to 8 pct. The specimens were marked with reference marks, electropolished, annealed at 900°F for 24 hr and at 1150°F for 12 hr, and repolished. The grain size of 2s aluminum produced by this treatment is comparable to that of high purity aluminum in the direction of its width of the specimen, i.e., there are 2 to 4 grains across the width of the specimen. However, the grains of 2s aluminum are 3 to 10 times longer in the direction of the specimen axis. On the other hand, the grain size of coarse grained 3s aluminum ranges from 10 to 20 grains across the width of the specimen due to the treatment just outlined and therefore is much smaller than that of both high purity and 2s aluminum. As in 2s aluminum, the grains are about 3 to 10 times longer in the direction of the specimen axis than in the direction of the width of the specimen. The arrangements of the grains in 2s and 3s aluminum were generally irregular; therefore it was difficult to follow the course of the grain boundaries. Results Method of Presentation: In order to show the arrangement of the grains, especially the direction and positions of the grain boundaries, traces of the grain boundaries on the four surfaces of the specimens were unfolded and mapped out after macroetching. Figs. 1 and 2 show the structural development drawings of specimens P-3 and P-8 respectively. The two flat surfaces (of which the front one faces the microscope) and the round-edged surfaces will be called the "front surface" and "back surface" and

Jan 1, 1954

By F. Brons, V. E. Marting

In the past, other authors.1, 2 have studied the influence of a skin effect on the productivity of a well. This skin effect, expressed by the skin factor S, is considered to be caused by a thin layer of impaired permeability immediately around the wellbore and extending vertically over the whole productive interval penetrated by the well. The skin factor S is defined as follows. Based on this, the impairment in productivity caused by a skin can be expressed by the fractional loss in productivity I, which is the loss in productivity divided by the total unimpaired productivity. For compressible flow in a stabilized well which drains a circular area of radius re, 1 is given by The present paper deals with a different kind of productivity impairment. Consider a well in which part of the productive formation is blocked off completely, either by incomplete penetration or by exclusion of parts of the productive zone by blank casing. In Fig. 1 (A, B and C), three examples are shown. Fig. 1(A) shows the situation where a well only partially penetrates the formation. This often is done to combat the actual or imagined danger of bottom-water coning. Fig. 1(B) shows a well producing from only the central portion of a productive interval. This type of completion is sometimes used where both water and gas coning are a problem. Although the case of a well producing through perforated casing cannot be treated in a manner similar to the previous two cases (where radial flow in the horizontal plane is assumed), Fig. 1(C) shows several intervals open to production and qualitatively describes this case (as will be discussed later). To study the loss in productivity in all these cases, two parameters are introduced which fully determine the impairment. The first is the penetration ratio "b," i.e., the total interval open to fluid entry divided by the total thickness of the productive zone. The second is the ratio hlrw. In this ratio, rw is the wellbore radius. The definition of h is more cumbersome. In Fig. 1(A), h is the thickness of the total productive interval. The streamline configuration for this case of partial penetration is basic to the other two cases considered (Views B and C of Fig. 1). It will be obvious from Fig. i (A) that the flow lines in the uppermost portion of the formation will be essentially horizontal, while those in the lower portion will curve upward toward the well. In Fig. 1(B), with only the middle portion of the zone open to production, the streamline configuration. of the upper half will be an exact mirror image of that in the lower half of the zone. Hence, for the case illustrated in Fig. 1(B), h is defined as one-half the total sand thickness. It follows, then, that in Fig. 1(C) h is one-half the distance between corresponding points in adjacent intervals. (In gun-perforated casing, h would be one-half the distance between perforations.) In a paper by Nisle4 and a paper given by the present authors5, the mathematical theory was developed for the cases under consideration. In the present publication, the emphasis is put on the results of these studies; consequently, the equations derived in Refs. 4 and 5 will be omitted, for the most part. The pressure drop p in a well producing from only a portion of the total formation thickness can, in analogy with Eq. 1, be expressed by Numerical solution of Eq. 5 by use of the IBM 650 leads to the following important conclusions. First, during a short period after starting production (usually on the order of a few minutes), the function p(b) is given by

By AIME AIME

. COUNCIL.* PRESIDENT OF THE COUNCIL. D. W. BRUNTON DENVER, COLO. (Term expires February, 1911.) VICE-PRESIDENTS OF THE COUNCIL. W. C. RALSTON SAN FRANCISCO, CAL. W. L. SAUNDERS : NEW YORK, N. Y. H. V. WINCHELL ST. PAUL, MINN. (Term expires February, 1911.) BENJAMIN B. LAWRENCE NEW YORK, N. Y. JOSEPH W. RICHARDS SOUTH BETHLEHEM, PA. ALBERT SAUVEUR CAMBRIDGE, MASS. (Term expires February, 1912.)

Apr 1, 1910

By AIME AIME

COUNCIL PRESIDENT OF THE COUNCIL. D. W. BRUNTON DENVER, COLO. (Term expires February, 1911.) VICE-PRESIDENTS OF THE COUNCIL. W. C. RALSTON SAN FRANCISCO, CAL. W. L. SAUNDERS NEW YORK, N. Y. H. V. WINCHELL ST. PAUL, MINN. (Term expires February, 1911.) BENJAMIN B. LAWRENCE NEW YORK, N. Y. JOSEPH W. RICHARDS SOUTH BETHLEHEM, PA. ALBERT SAUVEUR CAMBRIDGE, MASS. (Term expires February, 1912.)

Mar 1, 1910

By Norman Yarborough

Much has been written about the energy fuels including their standing with respect to reserves, their delivered Btu costs, their potential in the electrical generating market and their capabilities to meet a burgeoning demand. Yet, when all factors are placed in their proper perspective, the spiraling electrical energy market alone should guarantee each fuel a better than average market for the foreseeable future. In fact, a study made by the U.S. Federal Power Commission on the spare capacity utilities have on hand indicated that 39 of the 181 major utility systems had less than 10% reserves on hand at the end of 1969. Fuel supplies are critically low in some areas, especially in the Southeast, South Central and Midwest areas of the U.S. In other systems equipment shortages resulting from faulty equipment or delays in getting new equipment deliveries causes power failures during peak loads. In addition, lack of labor curtails the erection of some new facilities and prevents many other facilities from operating at capacity.

Jan 1, 1970

By AIME AIME

COUNCIL.* PRESIDENT OF THE COUNCIL. D. W. BRUNTON DENVER, COLO. (Term expires February, 1910.) . VICE-PRESIDENTS OF THE COUNCIL. J. PARKE CHANNING NEW TORE, N. Y. FREDERICK W. DENTON PAINESDALE, MICH. JOHN B. FARISH DENVER, COLO. (Term expires February, 1910.) W. C. RALSTON SAN FRANCISCO, CAL. IV. L. SAUNDERS NEW TORE, N. Y. H. V. WIINCHELL ST. PAUL, MINN. (Term expires February, 1911.)

May 1, 1909

By A. M. Gaudin

THE large increase in the use of selective flotation as contrasted with the collective flotation of a few years ago has focussed attention on the desirability of achieving accurate control of the pH of mill circuits. Although it is well-known that alkaline circuits result in dropping pyrite and that acid circuits conversely float it, but drop the gangue, there is little that is known, beyond question, ass to the action of the acidity or alkalinity of the circuits. A complete answer is not available at present but experiments -are now in progress at the University of Utah, whose aim is to find out what the effect is on recovery of a change in hydrogen-ion concentration and how this change is brought about. Broadly speaking, a change in hydrogen-ion concen¬tration seems to affect either the mineral surface, as was suggested by A. W. Fahrenwald in his paper "Surface Reactions in Flotation"1 (TRANS. 70, 647) or the attachment of the collecting agent on the mineral surface.

Jan 1, 1929

By W. E. Bearce

The recent concern for the recovery of even the finest fractions of coal preparation plant feeds has created needs for new equipment. Thermal dryers currently available have difficulty reducing the filter cake moisture on down to the desired point. This difficulty involves 1) the physical problem of handling this wet, sticky material and making each particle accessible to the hot gases, and 2) removing the extremely fine dried particles from the cooled gases. The dryer described in this paper handles the first of these problems, and eliminates the second by the substitution of steel balls for air as the heat transfer medium. As a general statement, the cost of preparing coal for market is inversely proportional to the size of the lumps or particles. In the not too distant past the finer sizes were discarded as being uneconomical to treat and this practice might be still continuing if it were not for the insistence of the public that this material be kept out of our streams. This being the only cost-free outlet, the disposal of fine refuse became a significant item of expense in every preparation plant. When this happened it was only reasonable to look to the recovery of the values in this material, not only to defray this expense, but to reduce the tonnage which had to be wasted. There seemed to be no device available suited to reducing the moisture in this material to what the market requires. All of the fine coal dryers commonly employed make use of air to bring the heat of combustion into contact with the coal particles. Any device employing air as a heat transfer medium, has the following two strikes against it in attempting to handle 28 mesh by 0 filter cake: 1) It is practically impossible to bring the hot air into intimate contact with the enormous number of fine particles stuck together in the cake. 2) Even if this can be effected, it is impossible to remove the dried coal from the air. A wet scrubber must be employed, the discharge of which must go back to the filter and dryer as a circulating load of the most objectionable sort, being the extreme fines. Various compromises have been used to cope with the problem of drying this relatively small tonnage of high moisture coal. Often some of the dried coal is mixed back with the feed to the dryer in an attempt to make the mixture more handleable and more available to contact with the hot air than the filter cake alone would be. This may help to some extent with the first problem but it does nothing about the second and a dryer operated in this way has to be oversized. Sometimes the filter cake is mixed with a coarser fraction for the same reason. Here again, while this may make a mixture (the particles of which are more readily brought into contact with the hot air), the problem of getting the fine coal out of the air remains and a larger percentage of the total coal to be dried is handled by the most expensive means. Mechanical dewatering has accounted for more and more of total coal drying lately and in many cases would satisfactorily handle the whole load, down to 28 mesh, if there were a means available for doing a good job on the —28 mesh by itself. The dryer which is the subject of this paper was designed expressly for doing this job — drying fine material by itself regardless of how wet it may be to start with, how fine it may be, or how gummy and sticky these properties in combination may make it. The essential features are depicted in Fig. 1. A rotating cylinder is supported on a frame in such a way that one end may be raised or lowered by hy-

Jan 1, 1968

By Samuel Daniels

In this paper are given the mechanical properties, determined by the Engineering Division, Air Service, U. S. A., of the 94 per cent. aluminum, 5 per cent. copper, 1 per cent. silicon alloy as sand-cast and as heat-treated commercially to Air Service Specification No. 11,300. This particular alloy was tested both in the cast and in the heat-treated condition. Tension and tension modulus values were obtained from machined and from un-machined test specimens; while data for shear, compression, impact, torsion, and for Brinell and Rockwell hardness were found from machined bars. Specific-gravity tests were made on sanded, un-machined specimens. The metallography of the alloy is useful as a control to heat treatment and presents some interesting peculiarities in regard to the two iron-bearing compounds. THE demand for an aluminum alloy, suitable for sand castings, that may be heat treated to meet requirements of high strength, ductility, shock and corrosion resistance, and ready machineability has led to the commercial development of a proprietary material that contains from about 4 to 5 per cent. of copper, 1 per cent. of silicon, and such impurities as iron, up to a maximum of 0.75 per cent., and manganese, in quantity usually less than 0.1 per cent.1 Magnesium is not generally present, for it tends to nullify the beneficial influence of the added silicon by forming magnesium silicide. The function of the silicon is to minimize casting difficulties and, structurally, to favor the precipitation of (insoluble) iron-bearing skeletons rather than the needles, which prevent full realization of tensile properties from heat treatment by stimulating intergranular fracture. The amount of silicon necessary to counteract the ill effect of iron is equal to or slightly more than the content of iron; the excess of silicon over this ratio, under certain conditions of heat treatment, enters with CuAl2, the principal hardening constituent, into solid solution and contributes somewhat to the strength of the alloy without appreciably impairing its ductility. The schedule of heat treatment of this alloy depends on the design (cross-sections) of the castings and on the nature of the tensile properties desired. Essentially, the process consists in heating the material at about-950° F., quenching in oil or in cold or boiling water, and artificially aging

Jan 7, 1925

By D. M. Warner, Samuel Daniels

In this paper are given the mechanical properties, determined by the Engineering Division, Air Service, U. S. A., of the 94 per cent. aluminum, 5 per cent. copper, 1 per cent. silicon alloy as 8and-cast and as heal-treated commercially to Air Service Specification No. 11,300. This particular alloy was tested both in the cast and in the heat-treated condition. Tension and tension modulus values were obtained from machined and from un-machined test specimens; while data for shear, compression, impact, torsion, and for Brine11 and Rockwell hardness were found from machined bars. Specific-gravity tests were made on sanded, un-machined specimens. The metallography of the alloy is useful as a control to heat treatment and presents some interesting peculiarities in regard to the two iron-bearing compounds. The demand for an aluminum alloy, suitable for sand castings, that may be heat treated to meet requirements of high strength, ductility, shock and corrosion resistance, and ready machineability has led to the commercial development of a proprietary material that contains from about 4 to 5 per cent. of copper, 1 per cent. of silicon, and such impurities as iron, up to a maximum of 0.75 per cent., and manganese, in quantity usually less than 0.1 per cent.' Magnesium is not generally present, for it tends to nullify the beneficial influence of the added silicon by forming magnesium silicide. The function of the silicon is to minimize casting difficulties and, structurally, to favor the precipitation of (insoluble) iron-bearing skeletons rather than the needles, which prevent full realization of tensile properties from heat treatment by stimulating intergran-ular fracture. The amount of silicon necessary to counteract the ill effect of iron is equal to or slightly more than the content of iron; the excess of silicon over this ratio, under certain conditions of heat treatment, enters with CuAl2, the principal hardening constituent, into solid solution and contributes somewhat to the strength of the alloy without appreciably impairing its ductility. The schedule of heat treatment of this alloy depends on the design (cross-sections) of the castings and on the nature of the tensile properties desired. Essentially, the process consists in heating the material at about 950" F., quenching in oil or in cold or boiling water, and artificially aging

Jan 1, 1926

By K. K. Kershner, W. A. Calhoun, C. W. Funk

Future resources of aluminum may require the utilization of low grade ores to provide a more permanent protection for the nation. Aluminum minerals such as cloy, shale, and high iron laterites may become important sources. An evaluation of reserves is given. New laboratory results are reported on the Vereinigte desilication process. THIS report on future resources of aluminum metal emphasizes the necessity for investigating utilization of low grade potential ores to provide more permanent protection for the nation. Partial or complete interruption of the importation of high grade aluminum ores must be given consideration. Ultimately, aluminum minerals such as clay, shale, and high iron laterites may become the principal sources of aluminum. The development of extractive processes for treating these low grade materials is a step in long-range national preparedness that should receive more attention. In formulating such processes, the application of beneficiation methods for the purpose of classifying the several types of minerals before subjecting each type to the more expensive extractive procedures should be considered, and a careful survey of the basic factors of power sources, transportation facilities, and sources of raw material should be made. Domestic Bauxite Resources Of the domestic supply of current, treatable-grade bauxite, 95 pct comes from Arkansas. The present reserve of Arkansas bauxite suitable for metal production, including abrasive-grade, Bayer-grade, and modified Bayer-grade ores, is 34,000,000 tons. The total reserve of bauxite of all grades is approximately 75,000,000 tons. Reserves are estimated on a mined and dried basis. Data available to the Bureau of Mines in 1948 to 1949 were used in preparing Table I, which shows a breakdown by grades of bauxite for about a half of the reserves of the state. The modified Bayer ore, 10,555,500 long dry tons, is based on a cutoff of 8 to 15 pct silica. The sub- marginal 10,074,700 long dry tons is assumed to contain more than 40 pct gibbsite, more than 15 pct silica, and less than 32 pct available alumina. A considerable amount of this low grade material was consumed in 1949 and 1950. Additional tonnages of bauxitic and kaolinitic clays are indicated by the Bureau of Mines drilling project.' Applying a 50 pct factor to arrive at long tons mined and dried, the results of this project are approximately 31,500,000 tons kaolinitic clay at +35 pct Al²O3 and 11,800,000 tons kaolinitic clay at 20 to 35 pct A1,0,. Total reserves of kaolinitic clays are probably quite extensive—several times the reserves shown in the Bureau's work. Total reserves of bauxitic and high iron clays from the drilling program and previously established figures are 63,980,000 tons. The mineral dressing methods,' the lime-sinter process, he lime-sinter modification of the Pederson process," the lime-soda sinter process,"-' and the Alcoa combination processa. have been described in the literature and will not be elaborated upon here. The less familiar Vereinigte Aluminium-Werke process used by the Germans during World War 11 may require some amplification. It was used to bene-ficiate boehmite ores containing 12 to 18 pct silica for a feed to the European Bayer process. Ore was

Jan 1, 1952

By Leonid Bryner

For many years, geologists have inferred a connection between the evolution of the earth's crust and ore deposition, a connection coming under the heading of metallogeny. In recent years the concept of metallogeny has assumed major importance in the exploration planning of Russian geologists in their quest for new mineral sources. As defined by Radkevich, metallogeny is "the science which studies the laws governing the distribution of ore deposits in the earth's crust." However, since it can be argued that metallogeny does not contain enough certitude to be classified as a "science," it would be more appropriately defined as the study of metallogenic provinces, and metallogenic epochs.

Jan 6, 1963

By AIME AIME

COUNCIL.* PRESIDENT OF THE COUNCIL. CHARLES KIRCHHOFF NEW YORK, N. Y. (Term expires February, 1912.) VICE-PRESIDENTS OF THE COUNCIL. BENJAMIN B. LAWRENCE NEW YORK, N. Y. JOSEPH W. RICHARDS SOUTH BETHLEHEM, PA. ALBERT SAUVEUR CAMBRIDGE, MASS. (Term expires February, 1912.) S. B. CHRISTY BERKELEY, CAL. W. A. LATHROP PHILADELPHIA, PA. GARDNER F. WILLIAMS WASHINGTON, D. C. (Term expires February, 1913.)

Mar 1, 1911