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By J. Rogers, K. L. Sutherland

THE relationships between collector and mineral, activator and mineral, and activator, collector and mineral will be considered herein. We propose to criticize current theories of flotation but we will not repeat the many pertinent arguments presented by Wark and Cox28 in 1937 in which the "chemical" or more strictly the "solubility" theory proposed by Taggart and co-workers22 is shown to be untenable. Recently Taggart, Arbiter and Kellogg24 have studied the long-chain aliphatic amines as collectors and have attempted to resuscitate the solubility theory for these particular collectors. Dean and Ambrose3 have felt that "we stumble over words" when we distinguish different mechanisms of adsorption. Our view is that nothing is more stultifying to the development of a science than attempts to force widely different phenomena into one classification. This oversimplification leads immediately to difficulties in the interpretation of results. EXPERIMENTAL PROCEDURE The response of minerals to activator and collector was determined by "captive-bubble" tests. The methods of preparation of specimens26 and of testing18 have been previously described. Results from captive-bubble tests were confirmed by flotation tests in glass-stoppered cylinders.25 The full lines shown in the figures relating solution composition to contact (flotation) distinguish solutions in which contact (flotation) is possible from those in which it is not. The curve is derived by successive approximation and the accuracy is ±0.2 pH units and ± 5 mg. per liter of collector or depressant. Solution compositions for which it was shown experimentally that contact or flotation is possible are marked by a circle, those for which it is not possible by a cross and those for which it is doubtful by a cross within a circle. It is assumed that at all other solution compositions within (without) the curve, contact or flotation is possible (not possible). After testing in the collector solution, the mineral was removed, washed, and tested by the captive-bubble method in water, or floated in a cylinder with frother only. In this way the composition of solutions in which a mineral was conditioned but in which properties of the collector solution prevented contact or flotation can be defined. The composition of solutions in which conditioning was possible lie between the full and broken curve, the experimental results being indicated on the figures by a square. The curves show the limits of composition of solution in which flotation in a cell would be possible. Many factors other than those considered in these tests determine recovery or grade of a given mineral in practice.

Jan 1, 1947

By K. L. Sutherland, J. Rogers

The relationships between collector and mineral, activator and mineral, and activator, collector and mineral will be considered herein. We propose to criticize current theories of flotation but we will not repeat the many pertinent arguments presented by Wark and Cox28 in 1937 in which the "chemical" or more strictly the "solubility" theory proposed by Taggart and co-workers22 is shown to be untenable. Recently Taggart, Arbiter and Kellogg24 have studied the long-chain aliphatic amines as collectors and have attempted to resuscitate the solubility theory for these particular collectors. Dean and Ambrose3 have felt that "we stumble over words" when we distinguish different mechanisms of adsorption. Our view is that nothing is more stultifying to the development of a science than attempts to force widely different phenomena into one classification. This oversimplification leads immediately to difficulties in the interpretation of results. Experimental Procedure The response of minerals to activator and collector was determined by "captive-bubble" tests. The methods of preparation of specimens26 and of testingin have been previously described. Results from captive-bubble tests were confirmed by flotation tests in glass-stoppered cylinders.26 The full lines shown in the figures relating solution composition to contact (flotation) distinguish solutions in which contact (flotation) is possible from those in which it is not. The curve is derived by successive approximation and the accuracy is ±o.2 pH units and ±5 mg. per liter of collector or depressant. Solution compositions for which it was shown experimentally that contact or flotation is possible are marked by a circle, those for which it is not possible by a cross and those for which it is doubtful by a cross within a circle. It is assumed that at all other solution compositions within (without) the curve, contact or flotation is possible (not possible). After testing in the collector solution, the mineral was removed, washed, and tested by the captive-bubble method in water, or floated in a cylinder with frother only. In this way the composition of solutions in which a mineral was conditioned but in which properties of the collector solution prevented contact or flotation can be defined. The composition of solutions in which conditioning was possible lie between the full and broken curve, the experimental results being indicated on the figures by a square. The curves show the limits of composition of solution in which flotation in a cell would be possible. Many factors other than those considered in these tests determine recovery or grade of a given mineral in practice.

Jan 1, 1947

By J. Rogers, K. L. Sutherland

The relationships between collector and mineral, activator and mineral, and activator, collector and mineral will be considered herein. We propose to criticize current theories of flotation but we will not repeat the many pertinent arguments presented by Wark and Cox28 in 1937 in which the "chemical" or more strictly the "solubility" theory proposed by Taggart and co-workers22 is shown to be untenable. Recently Taggart, Arbiter and Kellogg24 have studied the long-chain aliphatic amines as collectors and have attempted to resuscitate the solubility theory for these particular collectors. Dean and Ambrose3 have felt that "we stumble over words" when we distinguish different mechanisms of adsorption. Our view is that nothing is more stultifying to the development of a science than attempts to force widely different phenomena into one classification. This oversimplification leads immediately to difficulties in the interpretation of results. Experimental Procedure The response of minerals to activator and collector was determined by "captive-bubble" tests. The methods of preparation of specimens26 and of testingin have been previously described. Results from captive-bubble tests were confirmed by flotation tests in glass-stoppered cylinders.26 The full lines shown in the figures relating solution composition to contact (flotation) distinguish solutions in which contact (flotation) is possible from those in which it is not. The curve is derived by successive approximation and the accuracy is ±o.2 pH units and ±5 mg. per liter of collector or depressant. Solution compositions for which it was shown experimentally that contact or flotation is possible are marked by a circle, those for which it is not possible by a cross and those for which it is doubtful by a cross within a circle. It is assumed that at all other solution compositions within (without) the curve, contact or flotation is possible (not possible). After testing in the collector solution, the mineral was removed, washed, and tested by the captive-bubble method in water, or floated in a cylinder with frother only. In this way the composition of solutions in which a mineral was conditioned but in which properties of the collector solution prevented contact or flotation can be defined. The composition of solutions in which conditioning was possible lie between the full and broken curve, the experimental results being indicated on the figures by a square. The curves show the limits of composition of solution in which flotation in a cell would be possible. Many factors other than those considered in these tests determine recovery or grade of a given mineral in practice.

Jan 1, 1947

By W. Crafts, J. L. Lamont

Secondary hardening in tempering has long been recognized as a typical characteristic of steels containing large amounts of carbide-forming alloys. These steels, when quenched and tempered, tend to soften somewhat after tempering at low temperatures, and to reharden at intermediate tempering temperatures before finally softening to low hardness. This behavior in tempering has been studied by many investigators, chiefly with respect to thc secondary hardening of high-speed steels. The initial softening has usually been ascribed to decomposition of martensite and growth of iron carbide particles. The secondary hardening has been explained by formation of fresh martensite from residual austenite, formation of very fine alloy carbide particles and by precipitation hardening of metallic compounds in the ferritic matrix. However, factors derived for the calculation of tempered hardness in low-alloy steels1 indicated only a tendency toward retarded softening rather than a discontinuous rehardening. A study was, therefore, made to determine whether fresh martensite from residual austenite and precipitation hardening are essential to rehardening and the degree to which tempered martensite could be rehardened by precipitation of alloy carbides. The mechanism of carbide rehardening was also investigated to determine the nature of the process. The causes of secondary hardening in high-speed steel have received serious consideration for about thirty years. Among the earlier workers Bain and Jeffries2 in 1923 recognized residual austenite as a significant factor, but in addition, emphasized the effect of the formation of alloy carbide particles of "critical" size. They conceived that freshly quenched martensite forms low-alloy iron carbide at low tempering temperatures; with further tempering the iron carbide is then modified by alloying elements that can diffuse most readily at intermediate temperatures (850°F); and that the iron carbides grow in size by coalescence so that the steel tends to lose hardness. At higher tempering temperatures carbide stability rather than alloy availability becomes the controlling influence and in high-speed steel "iron-tungsten carbide is the most stable one and forms to the elimination of the earlier formed carbides. . . . The iron-tungsten carbide particles reach approximately the size for critical dispersion after a short reheat at II00 F." This concept, the formation of alloy carbide nuclei, redissolving of the iron carbide, and diffusion of carbon to the alloy carbide, was restated for vanadium steel in 1932 by Houdremont, Bennek, and Schrader. Subsequent studies have confirmed that iron carbide changes to alloy carbide at 1000 to IIOOOF, but the mechanism of the process has received little consideration.

Jan 1, 1949

When the writer first began his search for the early history of coal he was amazed at the paucity of information in literature about it, and while after six years many of the reasons for such a scarcity are understood, there are still many cases, even within the last two centuries, when one who can appreciate the tremendous part coal has played in the development of modern times, finds it hard to realize how little attention was paid to this material in those early clays. Occasionally a traveller or observer is found who foresaw how valuable coal was to be when industries were developed, but these were few and to most of those recording its occurrence it was just another mineral. George Washington was farsighted in his view of the development of this country and the need for means of transportation across the mountain barrier, but it was at least sixteen years after he must first have known of coal before he made any reference to it in his journals. He did, however, knowingly or not, select some valuable coal properties in the lands lie obtained in the West. This was then almost entirely an agricultural country, and what industries there were found a great abundance of wood fuel within easy access, there were no steam plants, and all iron was made with charcoal; in fact, the "captive mines" of the iron industry then were large timber "plantations," and when these were exhausted the furnace usually was abandoned and another one built elsewhere, as transportation of charcoal was quite expensive. Along the seaboard the cities and industries began to import coal from England and Nova Scotia early in the eighteenth century, but until the war of the Revolution began the total quantity of coal used yearly in this continent did not exceed nine thousand tons. In 1800 only two places, Pittsburgh and Richmond, Virginia, were using coal to any extent for domestic purposes and it was much later. than this that the amount of coal used in Philadelphia, New fork, and Boston exceeded that of wood. Practically all of the early travellers and writers mentioning coal are noted in the following pages. Several Englishmen who were evidently familiar with its use and value at home, mention its presence as being of great future promise to the young nation, but to nearly all it was more or less of a curiosity and the smoke caused by its use an abomination, and it

Jan 1, 1942

By L. W. Saperstein, D. Yeung, L. B. Phelps

Introduction The success of preventive methods for the mitigation of coal mine drainage formation will require a marriage of the minimization of initial coal mine drainage formation, the minimization of toxic fluid formation after toxic material disposal, the minimization of the mobilization and transpor¬tation of formed toxic fluids, and the maximization of the rate of diultion and attenuation of the formed toxic fluids. This paper contributes to the understanding of factors af¬fecting mobilization and dilution and attenuation of formed toxic fluids. When water containing a salt content different from in situ pore water in the soil is passed through a body of soil, the concentration of salts in the outflow will gradually change composition in a manner that depends on the kinds of hydraulic processes that occur in the soil. These processes are molecular diffusion, lateral dispersion, longitudinal dispersion, chemical reactions or exchange, physical adsorp¬tion, and biological retardation. This note considers only the first three processes. These three microscopic processes can be analyzed statistically on a probability basis. Such results, confirmed experimentally, indicate that a tracer introduced instantaneously as a point source will tend to form a Gaussian normal distribution as it moves downstream (Todd, 1964). Dilution During Flow The closed-form soltuion for pulse or instantaneous injec¬tion of a tracer during confined flow in a homogeneous porous medium shows that the maximum tracer concen¬tration at a point in space, x, after the time interval, t*, is given by [ ] where Aa is the effective flow cross-sectional area; A is the column cross-sectional area; a is soil porosity; M is mass of the injected tracer; C is concentration of the tracer in the permeating fluid and is a function of x and t*; D is the longitudinal dispersion coefficient; and va is the interstitial fluid velocity (Klotz and Moser, 1974). Therefore, the following conclusion can be made: • For a medium with a constant longitudinal dispersion coefficient, D, a constant soil porosity, a, a constant cross¬sectional area, A, and a fixed mass of injected tracer, M, Cmax will decrease as the time of peak outflow concen¬tration t* increases. • For a medium with a constant longitudinal dispersion coefficient, D, a constant soil porosity, a, a constant cross¬sectional area, A, a fixed mass of injected tracer, M, and a constant interstitial fluid velocity, va Cmax will decrease as the distance of travel, x, increases. • For a medium of constant cross sectional area, A, con¬stant soil porosity, a, a constant mass of injected tracer, M, and a fixed distance of travel, x, Cmax will decrease as D/va increases. Klotz and Moser (1974) concluded that D is about proportional to no.3 where r) is the kinematic viscosity; D is about proportional to a-3 where a is soil porosity; D in¬creases with increasing grain size; D increases as grains become less spherical; D increases with greater grain rough¬ness and angularity; D increases with increasing uniformity coefficient; and D is significantly affected by grain size and uniformity coefficient. The remaining parameters are not significant. Numerical Simulation Studies Numerical simulation studies were used to investigate the nature of flow and the optimum length of a toxic package within a saturated porous medium of fixed dimensions and configuration (Fig. 1). The width and position of the package was maintained constant (Phelps et al., 1981). Results indicate that if the package extends throughout the length of the model, the flow is vertically downward and

Jan 1, 1984

By Richard H. Olson

"Rarely in our technological society does the discovery of a new class of inorganic materials result in such a wide scientific interest and kaleidoscopic development of applications as has happened with the zeolite molecular sieves." That opening sentence in a landmark volume on zeolite molecular sieves by D. W. Breck (1974), is, if anything, an understatement. Zeolites were recognized as a new group of minerals in the 1750s, but it was not until 1930 that the first analysis of the crystal structure of a zeolite mineral was made. In the late 1940s research workers at Union Carbide Corp. began a program of zeolite synthesis and study which has resulted in one of the major research achievements of all time. Naturally, with the vast research and development efforts devoted to the synthetic molecular sieves, Union Carbide became concerned in the mid-1950s about its position should minable deposits of natural analogues be discovered. Zeolite minerals have diverse origins, and even a brief discussion of these is beyond the scope of this paper. The early work on zeolites was confined to igneous rock occurrences (e.g., amygdules and veins) which were formed by "space-filling;" these crystals tend to be euhedral, thereby rendering them appealing to both mineralogists and collectors. During the first year or so of Union Carbide's exploration (which began in mid-1957) attention was devoted solely to such igneous, occurrences. A landmark paper by Bramlette and Posnjak (1933) heralded the potential significance of the occurrence of zeolite minerals as alteration products of vitric ash and similar materials. In the summer of 1958, full attention was directed by Union Carbide to the search for deposits of this type in the western United States. Since then, such exploration has been continuous by both commercial firms and private parties. The future economic potential for natural zeolite deposits seems to be restricted to those of the "open-and-closed system" types as described by Sheppard (this chapter). Therefore, this and the following discussions will concentrate upon these types; the other types of zeolites in sedimentary rocks (e.g., deep-sea sediments, burial metamorphic, and hydrothermal) will be, for the most part, ignored. Despite the relative cheapness of natural zeolite deposits as compared with the cost of synthetic molecular sieves, there has been minimal development of zeolite mining in the US over the past 25 years or so. Mumpton (this chapter) discusses the present commercial utilization of natural zeolites and their future potential in detail, but perhaps the following will serve as useful background. In the early days of synthetic molecular sieve research and production, the efforts were concentrated largely upon such high-value applications as physical separation of components in a stream (based upon molecular size and geometry) and in catalysis. Due to a number of reasons (some of which are difficult for an outsider to understand), natural zeolite ores (beneficiated or not) have not made substantial inroads upon the use of the higher-priced synthetic molecular sieves for the foregoing applications, but this is not to say that such a condition will exist forever. Furthermore, in view of the many other uses which are now known, or which loom in the future, the competitive position of the natural zeolites vs. the more expensive

Jan 1, 1983

By T. A. Read, H. M. Otte

THEORETICAL analysis by Wechsler, Lieberman and Read of the crystallography of martensite formation has shown that the requirement for the existence of a macroscopically undistorted plane between austenite and martensite permits a calculation of the indices of the habit plane of the marten-

Jan 1, 1958

By M. Oka, C. M. Wayman

It has been known for some time1 that (110)b twinning is possible in bct martensite.* Any plane of the form (110) not parallel to the fourfold axis of tetra-

Jan 1, 1969

By N. M. Levine

WHETHER the United States and its allies can W meet the challenge of a war brought by the Communists will depend largely on who wins the battle of steel production. At the present stage of the world situation, the United States and the other members of the Western family of nations have the lead on iron curtain countries. But we have no sure way of knowing what is happening at Magnetogorsk and other Russian iron and steel producing centers. We must also face the possibility that we may have to meet the challenge alone. The fortunes of war and world politics can strip us of friends and co-fighters quickly. The destruction of Hiroshima and Nagasaki are indicative of what the world can expect if war-madness ever grasps the earth again. Our domestic supply of high grade open-pit and underground iron ore is dwindling because of the drain of three wars and higher than ever civilian consumption. The production of iron ore and its eventual use in blast furnaces are the critical problems of an armed democracy today. The world crisis has led to efforts towards beneficiation for increasing ore supplies. The huge reserves represented by the magnetic taconites at the eastern end of the Mesabi, once in production, should provide us with a substantial portion of our native ore for many years. The estimated 10 to 20 million tons of concentrates annually can be increased in an emergency. If we had a certainty of peace for the next 50 to 100 years, the situation would be a stable, hopeful one, aided by importations of high grade ore from sources such as Canada and Venezuela. The hard truth is that we have little surety of peace tomorrow morning. Let us assume 'the U. S. could build sufficient processing plants for increasing production of magnetic taconites under the pressure of national emergency. We must also recognize the power of atomic warfare to contaminate an area as large as the Eastern Mesabi. Thus, it becomes imperative to seek some means of protecting our ability to produce the steel we may one day need to survive. The nonmagnetic taconites, completely dwarfing the magnetic taconites areawise as well as tonnage-wise, might provide us with this insurance. Present indications are that they will be considerably more expensive to treat, but in a desperate situation we might be very grateful for ores yielding 40 to 50 pct Fe recoveries at grades of 53 to 58 pct Fe carrying low phosphorus. The University of Wisconsin, because of the difficult iron ore situation in the state, has been working on the nonmagnetic taconite problem for the past three years in the hope of making a contribution toward its eventual solution. In Wisconsin, the Western Gogebic Range has been the state's most effective iron producing area. Today however, only two mines are in operation, both underground and approaching depths of more than 3000 ft. The range, however, does have a large supply of nonmagnetic taconites and presents a promising field for study. While the Gogebic offers one large source of nonmagnetic taconites, Michigan and Minnesota have even greater supplies of such material. Alabama, the northeastern states and the West all have low grade iron ore sources which might be utilized under extreme conditions. The Gogebic Range located in northeastern Wisconsin and northwestern Michigan has a total length of about 70 miles, about 45 of which are in Wisconsin. The iron formation averages 500 to 600 ft in width, dips 70' to the north and strikes at approximately N 63° E. The formation is sedimentary and consists of six distinct members characterized by alternating divisions of ferruginous chert and ferruginous slate. The footwall is generally quartzitic and the hanging wall of a sideritic slatey character. The iron minerals are mainly hematites with some magnetites, goethites, limonites and small amounts of siderite. In the area studied, very small amounts of iron silicates were observed. The magnetites occurred mostly in the Anvil-Pabst and Pence members, mixed with hematites and representing roughly about 10 to 20 pct of the total iron in the formation, thereby characterizing it as nonmagnetic. The gangue is of various forms of silica such as chert, opal and flint. Complete liberation of iron and gangue minerals is rare. There is always some iron present in the chert ranging from jasper-like solutions to fairly coarse iron oxide specks. Likewise, one always finds finely dispersed silica within the iron minerals. In late 1943 the Bureau of Mines carried out a trenching and sampling program in the two mile stretch between Iron Belt and Pence in Iron County, Wis. Preliminary work was based on samples from one of the four trenches cut by the Bureau of Mines. More detailed work following the preliminary analysis was then undertaken on samples composited from all the trenches, thereby giving a wider and more representative coverage of the area. A study of the

Jan 1, 1952

Located 19 km (12 miles) north of the Carlin gold mine and 43 km (27 miles) north of Carlin, Nevada, is Carlin Gold Mining Company's Bootstrap mine. This deposit is similar in character to the Carlin ore, except it occurs in the upper plate formation of the Roberts thrust fault rather than in the lower plate rocks. The deposit was discovered over 50 years ago and operated on a small scale in the early 1960s using vat cyanide leaching. Newmont Mining Corporation acquired the property in 1967, and from an open pit mined 650,000 mt (717,000 st) of ore which was trucked to the Carlin conventional cyanide plant. (See Gold and Silver Cyanidation Plant Practice by F. W. McQuiston, Jr. and R. S. Shoemaker, Society of Mining Engineers, AIME, 1975. ) With the same grade of ore, the gold recovery by conventional methods is somewhat lower than that of the Carlin ore, even with a finer grind. Leaching tests were first conducted by the United States Bureau of Mines in 1968; and in 1971, ‘72, Carlin conducted extensive cyanidation investigations by bottle testing, simulated heap leaching in tall columns, and small scale pad heap leaches. Gold extractions ranged from 55% to 95% with low reagent consumptions. In 1974, a 545 mt (600 st) heap leach test was made at Carlin on pit-run low-grade material assaying 1.37 g per mt (0.04 oz per st). In a six week period the extraction of gold was 47.57'0. Carlin uses atomic absorption analyses on cyanide leach liquors to determine potential leach ore grade rather than fire assaying because it gives a more practical assessment of leach recovery than does fire assaying, which accounts for the total gold content. Before open-pit mining was started, plans were made to heap leach, the ore at Bootstrap which was too low grade for transport to Carlin. The topsoil outside of the designed pit area overlaid ancient lakebed clays which were found suitable for compaction to form an impervious base on which the dumps to be leached could be placed. By using the cost of truck haulage and milling at the Carlin plant and the price of gold 'at that time, a cutoff grade was established which resulted in the gold content of the first 150,000 mt (165,000 st) of the heap leaching ore being 1.51 g per mt (0.044 oz per st). An additional 500,000 mt (552,000 st) of lower grade material, assaying 0.96 g per mt (0.028 oz per st), is available for leaching as economics permit.

Jan 1, 1981

By H. M. Chance, T. M. Chance

The term 'Llow-sulfur coal," as used in this discussion, is limited to coals containing less, or very little more, than 1 per cent. sulfur. For certain purposes it might be advantageous to include coals that contain as much as 1.25 per cent. sulfur, because such coals have been considered as available for making metallurgic coke of fair grade; but the same reasoning might apply to coals containing as much as.1 1/2 per cent. sulfur, if facilities exist for utilizing such coal by admixture with coal containing less sulfur. , In Pennsylvania, it is not possible to define the exact geographic limits of the areas in which coals relatively low in sulfur exist, because variations in the percentage of sulfur occur irregularly and often abruptly. It is not uncommon to find areas, more or less circumscribed in extent, in which the coal is relatively high in sulfur although all the surrounding territory contains low-sulfur coal; and, similarly, small areas of low-sul. fur coal exist in districts where the coal is normally high in sulfur. These generalizations apply, with few exceptions, to the whole area underlaid with bituminous coal in the State of Pennsylvania, and also to each of the individual beds of coal in this state. Pennsylvania is poorly supplied with coals of the low-sulfur class. We find, however, as an offset to this condition, very large areas in which coal ranging from 1 to 2 1/2 per cent. sulfur exists in beds of good workable thickness. This coal, by washing, can be reduced in sulfur low enough to make coke of a high grade. While a considerable tonnage of workable low-sulfur coal remains in the Pennsylvania bituminous districts, it has been necessary to turn to the areas of higher sulfur coal for the supply of metallurgical coke. This utilization of the higher sulfur areas has been made possible either by washing or by selective mining. Washing.—Fine crushing of the entire feed is not generally necessary to the successful washing of Pennsylvania coals. This is due to the fact that the pyrite is rarely finely and uniformly disseminated throughout the coal but is usually confined to high-sulfur benches in the bed or to concentrations on the cleavage planes of the coal. Hence, by graded crushing and sizing it is frequently possible to at once reclaim those portions of the coal bed containing coal that is relatively free from pyrite.

Jan 1, 1920

By W. T. Cardwell, R. L. Parsons

This paper discusses the practical problem of estimating a single equivalent permeability for an oil reservoir, or a portion thereof, whose actual permeability varies in an irregular manner. Limiting averages for general types of permeability variation are developed, and illustrated by examples involving important, specific types of variation. Introduction The theory of the flow of fluids through porous media1"4 is becoming increasingly important in predictions of oil-reservoir behavior. In practical applications, however, reservoirs are seldom found to which simple theory strictly applies. Actual reservoirs have complicated shapes and nonuniform permeabilities and porosities. This paper discusses the problem of estimating a single equivalent permeability for an oil reservoir, or a segment of an oil reservoir, whose actual permeability varies in an irregular manner. The equivalent permeability of a reservoir segment is defined as the permeability of a homogeneous segment of the same dimensions that would pass the same flux under the same pressure drop- It is the permeability value that can be used in simple theoretical formulas to calculate the reservoir behavior. To the authors' knowledge, previous theoretical calculationst on systems of nonuniform permeability have been carried out only by Muskat'"; and he has not dealt with irregular variations, except in writing down the general differential equation for the pressure in variably permeable systems.lb In practical work, many calculations necessarily have been made to estimate equivalent permeabilities from the permeabiiity profiles obtained by core analyses. Regarding such calculations, Johnston and Sherborne6 say: Simple arithmetic and weighted averages have been tried on many wells and it has been found that, where frequent sampling has occurred, the arithmetic average is as satis- factory as a weighted average. It is possible that the application of statistical methods to the analysis of permeability data as recently presented by Law8 may prove fruitful. L,, has made a valuable contribution in showing how statistical analyses may aid in picturing the characteristics of a reservoir from those of a necessarily limited number of core samples. It is believed however that the particular problem of the estimation of equivalent permeabilities can be most directly approached from a fluid dynamical viewpoint as given in the present paper. An example is presented of the use of the conclusions herein in conjunction with Law's method. Theory In order to approach the problem of heterogeneity simply, it is interesting to consider a square block composed of four smaller, homogeneous, square blocks of porous medium, two of which have a

Jan 1, 1945

By Henry R. Joesting

DURING the past year and a half, the Territorial Department of Mines in Alaska has conducted a modest experimental program for the purpose of determining the extent to which magnetic and resistivity methods can be used in interior Alaska in connection with prospecting, mining and geological studies. Since little information is available concerning previous work,1,2 and since conditions differ considerably from those in most other regions, it was considered advisable to make a general study of the possibilities and limitations of the two methods, rather than a detailed study of any single problem. PROBLEMS One of the most serious handicaps to prospecting and geological study in interior Alaska, especially in the mature regions, is a cover of unconsolidated deposits ranging in thickness from a few feet to several hundred feet. These deposits, some of which are permanently frozen, consist of silt with varying proportions of vegetation and windblown material in the valleys and of residual deposits on the hills.3,4 The problems treated here are caused by the existence of this overburden: I. Location of buried placers. 2. Determination of depth and areal distribution of permanently frozen and of thawed unconsolidated deposits. 3. Location of water-bearing beds under unconsolidated deposits. INSTRUMENTS AND METHODS Magnetic and direct-current resistivity methods were used because they are relatively simple, rapid and inexpensive and because generally they are well suited to the study of the problems indicated. The instruments used were a vertical Schmidt-type magnetometer and a direct-current resistivity instrument similar to those used by the Geophysical Branch of the U. S. Geological Survey.5 For placer surveys with the magnetometer, a sensitivity of about 25 gammas per scale division was found suitable. For resistivity studies of frozen and thawed overburden and of underground water, the Lee partitioning method6 was found to be most generally suitable. In the Lee method a central potential electrode is placed midway between the two potential electrodes of the Wenner four-electrode configuration.7 Nonpolarizable electrodes were made from unglazed porcelain pots about 10 cm. high and 5 cm. in diameter. In order to retard evaporation of the electrolyte the sides of the pots were glazed, inside and out, with clear Duco lacquer. For resistivity work in cold weather, a nonfreezing electrolyte consisting of equal parts of ethylene glycol and a saturated water solution of copper sulphate proved satisfactory. Stainless steel rods of 3/4-in. diameter made excellent current electrodes because their bright finish enabled good ground contacts to be made.

Jan 1, 1941

By Henry J. Joesting

During the past year and a half, the Territorial Department of Mines in Alaska has conducted a modest experimental program for the purpose of determining the extent to which magnetic and resistivity methods can be used in interior Alaska in connection with prospecting, mining and geological studies. Since little information is available concerning previous work,l,2 and since conditions differ considerably from those in most other regions, it was considered advisable to make a general study of the possibilities and limitations of the two methods, rather than a detailed study of any single problem. Problems One of the most serious handicaps to prospecting and geological study in interior Alaska, especially in the mature regions, is a cover of unconsolidated deposits ranging in thickness from a few feet to several hundred feet. These deposits, some of which are permanently frozen, consist of silt with varying proportions of vegetation and windblown material in the valleys and of residual deposits on the hills.3'4 The problems treated here are caused by the existence of this overburden: I. Location of buried placers. 2. Determination of depth and areal distribution of permanently frozen and of thawed unconsolidated deposits. 3. Location of water-bearing beds under unconsolidated deposits. Instruments and Methods Magnetic and direct-current resistivity methods were used because they are relatively simple, rapid and inexpensive and because generally they are well suited to the study of the problems indicated. The instruments used were a vertical Schmidt-type magnetometer and a direct-current resistivity instrument similar to those used by the Geophysical Branch of the U. S. Geological Survey. For placer surveys with the magnetometer, a sensitivity of about 25 gammas per scale division was found suitable. For resistivity studies of frozen and thawed overburden and of underground water, the Lee partitioning method6 was found to be most generally suitable. In the Lee method a central potential electrode is placed midway between the two potential electrodes of the Wenner four-electrode configuration.7 Nonpolarizable electrodes were made from unglazed porcelain pots about 10 cm. high and 5 cm. in diameter. In order to retard evaporation of the electrolyte the sides of the pots were glazed, inside and out, with clear Duco lacquer. For resistivity work in cold weather, a nonfreezing electrolyte consisting of equal parts of ethylene glycol and a saturated water solution of copper sulphate proved satisfactory. Stainless steel rods of 3/4-in. diameter made excellent current electrodes because their bright finish enabled good ground contacts to be made.

Jan 1, 1946

By Henry J. Joesting

During the past year and a half, the Territorial Department of Mines in Alaska has conducted a modest experimental program for the purpose of determining the extent to which magnetic and resistivity methods can be used in interior Alaska in connection with prospecting, mining and geological studies. Since little information is available concerning previous work,l,2 and since conditions differ considerably from those in most other regions, it was considered advisable to make a general study of the possibilities and limitations of the two methods, rather than a detailed study of any single problem. Problems One of the most serious handicaps to prospecting and geological study in interior Alaska, especially in the mature regions, is a cover of unconsolidated deposits ranging in thickness from a few feet to several hundred feet. These deposits, some of which are permanently frozen, consist of silt with varying proportions of vegetation and windblown material in the valleys and of residual deposits on the hills.3'4 The problems treated here are caused by the existence of this overburden: I. Location of buried placers. 2. Determination of depth and areal distribution of permanently frozen and of thawed unconsolidated deposits. 3. Location of water-bearing beds under unconsolidated deposits. Instruments and Methods Magnetic and direct-current resistivity methods were used because they are relatively simple, rapid and inexpensive and because generally they are well suited to the study of the problems indicated. The instruments used were a vertical Schmidt-type magnetometer and a direct-current resistivity instrument similar to those used by the Geophysical Branch of the U. S. Geological Survey. For placer surveys with the magnetometer, a sensitivity of about 25 gammas per scale division was found suitable. For resistivity studies of frozen and thawed overburden and of underground water, the Lee partitioning method6 was found to be most generally suitable. In the Lee method a central potential electrode is placed midway between the two potential electrodes of the Wenner four-electrode configuration.7 Nonpolarizable electrodes were made from unglazed porcelain pots about 10 cm. high and 5 cm. in diameter. In order to retard evaporation of the electrolyte the sides of the pots were glazed, inside and out, with clear Duco lacquer. For resistivity work in cold weather, a nonfreezing electrolyte consisting of equal parts of ethylene glycol and a saturated water solution of copper sulphate proved satisfactory. Stainless steel rods of 3/4-in. diameter made excellent current electrodes because their bright finish enabled good ground contacts to be made.

Jan 1, 1946

By C. A. Bruch, W. E. McHugh, R. W. Hockenbury

EXPERIMENTAL results of the last decade have shown that both accelerator particles and reactor radiations produce significant changes in the properties of metals. These changes, called radiation damage, are important from both academic and engineering viewpoints. An understanding of the radiation damage produced by reactor radiations is difficult, because many kinds of particles having varying energies are present. Therefore, many fundamental studies are being conducted using accelerators in order to obtain nearly mono-energetic beams of various charged particles. Furthermore, many of these experiments are conducted at low temperatures in order to freeze in the radiation-produced lattice defects, after which the specimens are annealed to study the movement of the defects. It is found that although much of the low temperature radiation damage disappears by annealing at room temperature, a significant amount remains. Because there is no assurance that irradiation followed by annealing at a higher temperature will produce the same effect as irradiation at the higher temperature, and because there is an immediate interest in reactor radiation effects during exposures at and above room temperature, a major program is in progress at this laboratory to investigate some of these effects. This paper, representing a part of the program, compares the radiation damage to a group of metals which were exposed under nearly identical irradiation conditions. The metals, representing the three major crystal systems, include copper, nickel, titanium, zirconium, iron, molybdenum, and type 347 stainless steel. The effects of reactor radiations have been treated from a theoretical viewpoint by Seitz' and Ozeroff.' The problem considered by them has been the atomic displacements produced in an infinite medium by mono-energetic beams of both neutrons and charged particles. For reactor experiments, this treatment is not wide enough in scope, because specimens and reactor components are finite, and there are continuous energy spectra of the various particles. Therefore, the theoretical considerations will be extended in this paper to cover reactor conditions and the findings will be compared with the observed radiation damage. Experimental Materials—The six basic metals for this investigation were of commercial or higher purity, and the type 347 stainless steel was of commercial quality. These materials were supplied in various forms ranging from ingots to finished rods, and were fabricated to rods approximately % in. in diam and annealed for specimen stock. A summary of data pertinent to these materials is shown in Table I. The values for chemical compositions include both actual analytical values and typical values supplied by the manufacturer. More information concerning typical

Jan 1, 1957

By E. B. Fitch

The operating behavior of liquid-solid cyclones is outlined, together with the nature and range of the process results obtainable, to serve as a background for engineers wishing to consider application of this new process tool.

Jan 3, 1953

By Walter Kauenhowen

The crude-oil production of Germany without Austria during 1938 amounted to 3,864,518 bbl., representing an increase of 21.7 per cent over the 3,173,373 bbl. produced in 1937. Adding the Austrian production, the crude-oil production of the new German Reich totaled 4,259,717 bbl. during 1938, representing an increase of 25.3 per cent compared with the respective figures of the previous year. According to published official data, and using a conversion factor of 1 metric ton equaling 7 bbl., the oil production of Germany in 1938 was as shown in Table 1. A semiofficial publication1 states that the program of the crude-oil industry for the second year (1938) of the four-year plan was successfully accomplished. According to the same source, new drilling developments at the following localities were promising: Reitbrook near Hamburg, Heide in Holstein, Eicklingen-Sandlingen near Celle, Steimbke near Nienburg, Worms in the Rhine Valley, Gifhorn near Braunschweig, Mölme near Oberg, and at other places. The drilling activity for oil is illustrated by the figures in Table 2.

Jan 1, 1939

By Walter Kauenhowen

The crude-oil production of Germany without Austria during 1938 amounted to 3,864,518 bbl., representing an increase of 21.7 per cent over the 3,173,373 bbl. produced in 1937. Adding the Austrian production, the crude-oil production of the new German Reich totaled 4,259,717 bbl. during 1938, representing an increase of 25.3 per cent compared with the respective figures of the previous year. According to published official data, and using a conversion factor of 1 metric ton equaling 7 bbl., the oil production of Germany in 1938 was as shown in Table 1. A semiofficial publication1 states that the program of the crude-oil industry for the second year (1938) of the four-year plan was successfully accomplished. According to the same source, new drilling developments at the following localities were promising: Reitbrook near Hamburg, Heide in Holstein, Eicklingen-Sandlingen near Celle, Steimbke near Nienburg, Worms in the Rhine Valley, Gifhorn near Braunschweig, Mölme near Oberg, and at other places. The drilling activity for oil is illustrated by the figures in Table 2.

Jan 1, 1939