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By F. E. Brackett

THE simplicity of the propeller or disk fan, its small size and low cost, has, in recent years, led to an extended use of ventilators of this type at mines where only slight pressure is required. On this account the author of this paper has prepared for the new edition of Peele's Mining Engineers' Handbook a more accurate method of computing the required size, power, and so forth, than was possible for the first edition. The main object of this paper is to set forth the data collected in the course of that work, and to discuss the subject with more latitude than would have been advisable in a handbook, even if space had been available. Theory of Fans A great deal has been written about the theory of fans from Rankine's time down to the present. Nevertheless a rigid mathematical analysis of the propeller fan seems to be wanting. A general idea of the mechanics and difficulties in the way of analysis may be gathered from the following: The useful pressure and velocity effects of the oblique impact of the vanes on the axial current would evidently be nil if the blades were perpendicular to the plane of rotation, or if they were of such helicoidal form that the screw pitch multiplied by the speed represented an axial velocity agreeing with the actual velocity. Somewhere between these zero angles there is a pitch which, under given conditions of flow, would produce the maximum useful effect. A true helicoidal blade can be so arranged that it would offer no retarding effect on the air current at any part of the wheel, provided the axial velocity be assumed the same in all parts of the cross-section of the air course, but if plane surfaces are used, it is possible, under some conditions, that the air would be retarded at the middle parts of the wheel while it was accelerated at the circumference. Whatever be the form of vane, it seems evident that the tips are far more effective than the center of the wheel, because of their higher velocity. For this reason some investigators believe that a backward current forms through the middle of the wheel and that part of the air is circulated in a radial axial loop. Ignoring the possible existence of this eddy and the friction of the walls of the air course; and assuming the axial velocity of the air through all parts of the wheel, some rational analysis of the impact might be made according to the theory of deflecting surfaces, were it not

Jan 1, 1928

By F. M. Perkins, R. H. Jamison

Publications concerning scaling laws for laboratory flow models of oil reservoirs indicate that the relative permeability and capillary pressure relations must be the same functions of saturation in the model and its prototype. In this paper, the relative permeabilities and saturations are redefined in a way which permits one to have diflerent relative permeability and capillary pressure relations in the model and prototype. The development of the new scaling criteria is demonstrated by deriving scaling laws for one simple flow problem. INTRODUCTION The successful application of information gathered through bench-scale model studies to the prediction of multi-phase fluid flow behavior in petroleum reservoirs requires careful consideration of the scaling criteria. The requirements which must be met for a small-scale model to duplicate the behavior of a much larger reservoir prototype have been discussed by Leverett, et al,' Rapoport,2 and Geertsma, et al.3 According to these authors, the relative permeabilities to water, oil and gas and the dimensionless capillary pressures must be the must have the same values in the model and prototype. Furthermore, they point out that the viscosity ratios must have the same values in the model and prototype. In addition to these requirements, other scaling criteria are given which, when considered, usually dictate a much higher permeability in the model than exists in the reservoir. Since the more permeable model sands may have connate-water and residual oil saturations quite different from those in the prototype, the scaling requirements pertaining to the dependence of relative permeabilities and dimension l ess capillary pressures on saturation usually are not met. Also, if the model fluids are selected to give equal viscosity ratios in the model and prototype, one may find greatly different mobility ratios* in the two cases and, therefore, may expect grossly different flow patterns. For this reason, Craig, et al,' correlated the results of their model studies with mo- bility ratio rather than with viscosity ratio. As yet, however, no satisfactory method has been advanced which permits use of anything other than the scaling requirements outlined in the previously mentioned papers. The purpose of this paper is to present a method of developing a set of scaling criteria which permits different relationships between saturation and relative permeability or capillary pressure in the model and prototype. Rather than attempt to report scaling criteria for a variety of practical situations, this paper demonstrates by use of one simple example how the modified scaling criteria are derived.

By Benjamin Lustman, Robert F. Mehl

THE study of the high-temperature oxidation of pure metals, intensively pursued experimentally since the pioneer work of Pilling and Bedworth1 and supplemented by the recent theoretical work of Wagner2 is now well advanced. The important field of low-temperature oxidation-i.e., oxidation extending only through the temper color range of thicknesses with the formation of thin oxide layers in the range from o to 1000-2000 Angstroms-has not, however, reached so satisfactory a state, owing largely to the experimental difficulties that attend the formation and study of thin films; most of the work has been performed on abraded specimens whose surface irregularities approximated the thickness of the films formed. It has been pointed out that the rates of oxidation of different crystal faces are different and that the difference may be related to the orientation relationships that obtain between the metal crystal and the superimposed oxide crystal; it has also been suggested that this orientation dependence should manifest itself in rates of oxidation and perhaps also of corrosion in aggregates bearing preferred orientations. 3,4 An attempt to measure the rates of oxidation of different crystal faces of alpha iron demonstrated this difference in rate,4 but the dependence of rate on orientation was not simple; the method of measuring thickness, consisting of a color comparison with barium stearate multi-films of known thickness, was not wholly satisfactory. For these reasons it was felt that a study of the rate of oxidation of single crystals prepared with surfaces as smooth as possible, using a sensitive method giving true film thickness, should be profitable. Copper was chosen because of the ease of reduction of the primary oxide film and because the orientation relationships between metal and oxide and the composition of the oxide films formed at low temperatures are known; for thin films formed at low temperatures, Cu2O alone occurs.22-24 EXPERIMENTAL PROCEDURE Various methods of surface preparation were attempted in order to obtain a surface that would oxidize uniformly and reproducibly. Electrolytic polishing by the method of Jacquet5 and electrolytic and mechanical polishing followed by annealing in vacuum and in purified hydrogen at various temperatures were tested. The procedure finally adopted consisted in a fine metallographic polish followed by an anneal in purified hydrogen at temperatures of 900º to 1000°C. for 12 hr. or more. The surface so produced was very bright and smooth, with no trace of specular etching (though some grain-boundary etching was observed); indeed, fine scratches produced by the final polish were entirely removed by the high-temperature anneal.

Jan 1, 1941

By Herbert M. Wilson

We of the employer class represent labor in the social organization and in industry just as truly as do those who labor only with their hands, and, because our labor is chiefly with our brains, the duty is all the more imposed upon us to use those gifts in which we excel in helping steer a clear course through the turbulent waters in which we are now enmeshed. Only their selfish engrossment in the daily tasks they were employed to perform could possibly have permitted the great majority of the intelligent and industrious German people to become terrorized by a handful of the idle, the vicious, and the criminal, whom the elections to the National Assembly showed to be in as pitiful a minority as they are in Russia, in this, and in other countries. It is the leisure unemployment of the I.W.W.'s, the Bolsheviki, and the Sparticans that has enabled them to devote their whole time to a concerted and aggressive struggle against the great majority of those of the world's workers who are unorganized, and who are therefore even in opposition one to the other. In union there is strength, and this was never better illustrated than by these conditions. The great fallacy of our previous attitude toward social and industrial problems has been the belief that labor, by which we commonly mean organized or physical labor, is something antagonistic to and having a different object in life from that great body of unorganized laborers who work with their brains. Our difficulty has been our lack of will or opportunity to think. The hurry of our daily struggle to earn our livelihood under the nerve-racking pressure of modern civilization has left us no opportunity for quiet thought and study. The physical laborer, and above all the laborer in the mines, on the other hand, has all his hours of toil in which to think over, in all their varied aspects, those problems that concern his immediate, personal well-being. As a result he has arrived at perhaps a more true appreciation of the facts of life in their relation to social and industrial conditions than we. Have we not too readily adopted the view that, as the managers of industry under the direction of capital, it has been our duty to think and act in opposition to labor, rather than to realize that we also are laborers, have like aspirations, and should participate in a free and aggressive solution of these problems rather than leave their solution

Jan 1, 1919

By G. A. Crowe, W. T. Bishop

While the literature in the United States on general polarographic technique is extensive, very little appears to be directly applicable to the analysis of flotation tailings. For this reason, it seemed worth while to present a few polarographic methods of ore analysis that have been in constant use in the laboratories of the Hercules Experiment Station for the past few years. At the time of our initial investigation of the polarographic method, there was little or no mention of its specific application to flotation tailings. It was therefore necessary for us to establish suitable conditions for the analysis of our flotation tailings and to consider possible interfering constituents. The polarograph, or dropping mercury electrode, method was discovered in 1925 by J. Heyrovsky and M. Shikata,1 of the Charles University, Prague. This method has since received extensive development and the literature contains many articles on the use of the polarograph for the quantitative determination of metals as well as anions, oxygen in solution, and reducible organic compounds. Kolthoff and Lingane,² by the publication of their book, "Polarography," in 1941 did much to advance the knowledge and use of the polarograph. In chapter 25 of that book, methods for the polarographic analysis of brass, steel and iron products, alloys, and zinc ore are given. Aluminum,³ cadmium,³,4 cobalt,4 cop-per,³-9 gold,10 iron,3,11 lead,³,l2,l³ molybdenum,14 nickel,4,8,9 tin," and zinc³,4,5,7 in ores have been analyzed by the polarograph. However, most of the work on tailing samples has been published in Russian journals and translations are not yet readily available. In this paper we will describe the method that was developed and used in our laboratory for the determination of copper, zinc, and lead in flotation tailings. Principle OF the Method The polarograph is an instrument for applying a potential to a mercury pool and a dropping mercury electrode separated by a solution, and for measuring the resultant electrical current. The procedure is essentially a small-scale electrolysis, in which the voltage required to reduce or oxidize the material identifies it qualitatively and the current measures the concentration quantitatively. Different constituents in a sample may often be determined simultaneously provided they reduce at sufficiently different voltages. An example is the determination of copper and zinc in the same solution. The reduction potentials are quite far apart, as shown in Fig. I. The polarographic method is particularly useful in the range of concentration between those normally determined by spectographic and chemical methods. In

Jan 1, 1947

By J. F. Poland

Location of Basins and Geologic Features of Occurrence: The major ground-water resources of California occur and are stored in the many large alluvium-filled valleys of the state. The deposits of Quaternary age which hold the ground water commonly are called valley fill. Meinzerl has discussed the characteristic features of this fill and showed that for western United States its distribution is concentrated chiefly in western Utah, Nevada, central Oregon, California, southern Arizona, and central New Mexico (see fig. 1). For California the principal ground-water basins are shown on fig. 2. Except for the Mojave Desert and the "Basin and Range" Valleys (fig. 2, Nos. 23 and 23A), which are not shown individually, the basins outlined on fig. 2 contain all the large reservoirs in valley fill within the state. The Sacramento and San Joaquin Valleys (fig. 2) together comprise the Great Central Valley of California, which has an area of about 18,000 square miles. The Sacramento Valley contains about 5000 square miles of valley lands, approxi- mately equal to the area of Connecticut; the San Joaquin Valley embraces about 13,000 square miles, equivalent to the areas of Massachusetts and Connecticut combined. Both the area and the ground-water use in the Central Valley is far greater than for all the other shaded alluvial basins of fig. 2 added together. Except for the Sacramento Valley, all the major ground-water basins of the state are south of Sacramento. The valley fill in these ground-water basins has been transported by streams and most of it has been laid down in alluvial fans, producing the typical alluvial-fan structure of aquifers radiating as tongues from a prismatic pile of coarse, permeable debris at the canyon mouths; these aquifers are encased down slope by poorly sorted materials consisting of a clayey matrix with imbedded pebbles and boulders, interbedded with flood-plain silt. In the deeper inland structural valleys, the alluvial deposits interfinger at depth in the valley bottoms with horizontally bedded lacustrine sand, silt, and clay. The San Joaquin Valley is a good example. In the coastal valleys exposed to the sea, such as the Los Angeles coastal plain, the alluvial fans pass coastward into lagoonal and thence to shallow marine deposits. In all these basins, the gravel is coarsest and most permeable near the apexes of the fans, but tongues or lenses of clean gravel and sand may extend for many miles down the fan. Thus, these water-bearing structures are in a position to absorb stream flow near the canyon mouths and to transmit it through the buried radiating conduits.

Jan 1, 1951

By W. T. Cardwell

This paper presents a theory for estimating the rate of gravity drainage of a liquid out of a sand column. Account is taken of the variation in permeability to the liquid as the saturation in the upper part of the sand becomes less than 100 pct. The theory is confirmed by previously published experimental data. Introduction Petroleum engineers have expressed the need for 4 theory of gravity drainage. Brunner,' in particular, has pointed out that some type of mathematical theory is necessary to begin the application of laboratory data to field problems. Muskat and his associates2'3-4 have recently made contributions to the theory of gas-drive behavior and have indicated an intention to apply their methods to water-drive systems. No theory of gravity drainage rates has been developed, however, and it seems desirable to formulate one at this time. Differential Equations of Capillary Flow The flow of liquids in partially saturated porous media has been studied by many investigators.6-10 Richards6 presented derivations of fundamental differential equa- tions governing two-phase capillary flow; and used simplified forms of those equations in solving a steady-state problem. Muskat and Meres6 presented and used equations different from those of Richards. Their equations did not explicitly involve capillary pressure gradients; but included, on the other hand, terms expressing the effects of the evolution of gas from the liquid phase during flow. Leverett8 stated in 1940 that "previous work on the flow of fluid mixtures in porous solids [had] failed adequately to account for all of the three influences that cause motion of the fluids: capillarity, gravity, and impressed external pressure differentials." Leverett's basic equations, however, were specialized forms of the general equations of Richards,5 which had actually taken account of the three influences mentioned by Leverett, but had not been used in a problem involving all three. The fact is that our knowledge of capillary flow and our ability to express this knowledge in differential equations exceed our ability to solve the equations except in a few cases. General differential equations have usually been of little more than formal value. In solving practical problems, it has been necessary to develop specific equations, preserving terms that involved the factors important in those problems, and purposefully neglecting other terms that were not of predominating influence. This is the method followed here. It is believed that the solution of the particular problem and the scheme of the solution itself are new.

Jan 1, 1949

By F. C. Oliphant, George H. Fancher

Two samples of drilling mud from the Hastings oil field, Texas, were tested, and the solids in each were separated into small fractions of a limited range in particle size. The mineral composition of each fraction by X-ray analysis is reported, and the results are interpreted in relation to other measured quantities, such as the physical properties of the original samples and the density of the various fractions. It was found that only 7 to 8 per cent by weight of the solids was of colloidal dimensions and that neither of the samples contained montmorillonite but did contain illite. Considerable calcite was also found. These data should be useful to the geologist interested in the origin and history of sedimentary strata as well as to the petroleum engineer. Introduction The questions, What is good drilling mud? What constitutes bad drilling mud? are pertinent, because the proper use and control of drilling fluids has been a factor of great importance in the successful drilling and completion of oil wells since the days of Captain Lucas. Adequate control of the characteristics of drilling fluids has assumed greater significance comparatively recently because of the problems introduced by caving formations in deep wells, costly blowouts and impressive mud bills. Much is known about the solution of some of the problems but, despite extensive research directed toward a better understanding of the physical and chemical properties of clay suspensions, it is difficult to define precisely a drilling mud, and much more difficult to say what constitutes a good mud. It is generally believed that the smaller particles of a drilling mud greatly affect its physical properties. In fact, it is customary to blame the colloids in a mud for nearly everything that goes amiss, because colloidal properties have effects out of all usual proportion on viscosity, filtration rate and reaction to electrolytes. It is germane to know whether drilling muds possess colloids and if so, the quantity and kind. Source oF Samples Two drilling muds from the Hastings oil field, Brazoria County, Texas, were selected because it is generally agreed that in this oil field good natural muds made solely from formations penetrated by the drill can be used until the well is nearly ready for completion. Customary drilling procedure in this field is to spud in with water, set a protective string of pipe, drill to 2500 ft. and set the surface casing. Drilling is continued to 5500 ft. with no treatment of the drilling fluid other than addition of water to

Jan 1, 1943

By M. R. Tek, F. H. Poettmann, M. L. Grove

The general problem of single-phase natural gas flow through porous media has been considered both by mathematical analysis and field experiments. Theoretical studies on the fluid dynamics of natural gas wells resulted in derivations of expressions which permit a ber-ter understanding of the flow mechanism for conditions under which Darcy's law is no longer valid. In applying these results to natural gas production and testing technology, special emphasis war placed on the study of low permeability, slowly stabilizing formations. These applications resulted in a method of predicting the performance coefficients of tight natural gas wells. The calculation of the performance coefficient requires the determination of the "test-index", pkh/µ, the drain- age radius, R, and the effective wellbore radius, rw. Methods for estimating these parameters from field data were also developed. Field data from 15 wells were collected and analyzed. The measured values of the performance coefficients were compared with the predicted values. This statistical evaluation gave a bias of 7.14 per cent and a standard deviation of 11.6 per cent. INTRODUCTION The performance of a natural gas well is determined by the physical properties of the reservoir rock, the extent and the geometry of the drainage area, the properties of the flowing fluid, and the conditions of pressure distribution within the drainage matrix. The relation between the quantity of gas delivered and the pressure drop within the reservoir is characteristic of the behavior of each well and is often referred to as the back-pressure behavior of the well. It is well established that for normal, single-phase gas wells the relationship between the gas delivery rates and the bottom-hole pressure take, in general, the form, Q = c(P3 8 -P2 1)n. ,.......(1) where C is the performance coefficient, and n is the exponent corresponding to the slope of the straight-line relationship between Q and (P2 s, — P2 l) plotted on logarithmic coordinates. The determination of a well's performance by the back-pressure behavior not only permits the production engineers to analyze many operating problems, but also provides necessary information useful and essential to predict the future development of the field.' Important engineering and production problems such as calculation of gas deliverability into a pipeline at a predetermined line pressure, design and analysis of gas-gathering lines, determinations of spacing and number of wells to be drilled during field development to meet future market or contract obligations, etc., all depend, at least in part, on the availability and use of reliable back-pressure curves.' In the past the behavior of gas wells was evaluated

Jan 1, 1958

By W. Rostoker

INTRODUCTION THE process of diffusion alloying of mixed powders offers attractive possibilities both commercially and experimentally. It avoids the fabrication difficulties arising from high alloy contents. Indeed, the process is facilitated by larger alloy additions. The direct formation of the part or test piece and the opportunity to perform machining operations under more favorable conditions are of no small importance. However, it is necessary to make only brief mention of the interesting features. As yet there have been few attempts to study this process in detail and to carry it to completion, if such is possible. It was intended not only to measure the intermediate and optimum magnetic properties of sintered alloys but to use magnetic testing itself as a means of following the progress of alloying under various conditions. Having established that alloys could be successfully synthesized by this technique, the opportunity was taken to study the magnetic properties of several alloys of iron and silicon which had hitherto been too difficult to prepare in suitable test piece form, While avoiding some of the difficulties inherent in the fabrication of alloys by orthodox methods, the diffusion alloying process introduces a few of its own. The first of these is the evaluation of the approach to homogenization. In recent years some notable contributions have been made to this question, but considerable uncertainty remains in its definition and evaluation. This work has concerned itself with further study of this problem and it is hoped that more light has been shed on it, The second of these difficulties arises from the presence of porosity. It is inevitable that in the consolidation of a loose bulk of powder, there should remain some voids unless extremely high pressures are repeatedly applied. It was therefore of importance to investigate their effect on magnetic properties. Recently this effect has been studied and certain predictions made of its behavior. It is believed that the experimental results presented here provide a sound substantiation of the theoretical treatment. The attempt has been made to synthesize five alloys of the iron-silicon system and three each of the iron-nickel and iron-cobalt systems. A series of experiments was also conducted on some of these alloys to test their susceptibility to heat treatment. Some unfortunate experiences have provided opportunity to report data on the deleterious effects of nitrogen on magnetic properties when present as a contaminant in protective atmospheres. MATERIALS, PREPARATION OF SAMPLES AND TESTING The purest materials available were employed for this work. A specially purified,

Jan 1, 1948

By Emby Kaye

It is the purpose of this paper to outline briefly some of the considerations that enter into the economics of so-called recycling, the generic designation of the relatively recently developed process by which a condensate† is separated from gas-distillate gas at high pressure and the residual gas returned to the reservoir. This subject necessarily embraces not only a discussion of factors that should be considered in projecting a recycling operation, such as estimating reserves, investment and operating costs, but also a comparison of condensate with other types of petroleum. The place of condensate in its relation to the total supply of crude oil is pointed out as well as certain logical methods of product disposal. The cost of drilling wells and lease maintenance is not pertinent to this discussion because income and revenue are in this paper confined to that retained by the plant or plant operator for supplying processing facilities for the gas. Before the development of recycling a great many gas-distillate gas fields in Louisiana and Texas provided no income to their owners. When gas was sold from these reservoirs it was accompanied by irretrievable losses of condensate in the formation. The understanding of the func- tion of retrograde condensation resulted in the introduction of a new commercial petroleum recovery process for these hitherto unexploited fields and now permits the conditioning of this type of wet gas field for the sale of dry gas therefrom without waste. Some Economic Factors The study of a gas-distillate field for possible exploitation necessarily involves the critical appraisal of a number of elements, chief of which will be discussed here: (I) estimate of distillate in place, (2) estimate of distillate that can be brought to the surface, (3) available market, (4) costs. The considerations affecting the estimating of distillate reserves in place are in the main subject to the same errors as are involved in determining dry gas reserves. Determinable data including acreage, sand thickness, reservoir pressure, reservoir temperature, porosity and connate water provide the basis for calculating the volume of gas in place. Ample allowance must be made for connate water, which may occupy from 20 to 35 per cent of the pore space of the sand. The factor of supercom-pressibility is to a considerable extent nullified by the reservoir temperature. It has been considered well advised to allow this factor to serve as a cushion. With the gas reserves calculated, it remains only to assay the distillate content of the gas. Those familiar with the handling of "wet" gas at high pressure readily appreci-ate the variables in sampling gas from

Jan 1, 1942

By Fredrick C. Kruger

Anthropological diggings have revealed that the American Indians carried on intertribal trade in flint, obsidian, ochre, and other mineral commodities, indicating that mining was practiced before the arrival of the white man from Europe Carbon datings from the native copper pits on Isle Royal and Keweenaw Peninsula, Michigan, have yielded dates as early as 5555 BC for this mining. As early as Pliocene time, Eolithic-man fashioned artifacts of stones probably found on the surface, but by late Quaternary, Neolithic man was sinking shafts and mining underground for flint. Because placer gold was easily recognized and easily worked, it was used for ornamental purposes by nearly all cultures before other metals were discovered The Chaldeans hammered copper objects approximately 4500 BC and copper was used in India and China about 3000 BC. An ancient trail from the Nile to the Sinai led to the mines of copper and turquoise Paintings and bas-reliefs of Egyptian tombs dating around 3000 BC depict maps, mining, and smelting in this area. It is interesting that despite this widespread and long history of mining, Agricola records that the first mining laws were developed by the Greeks at Laurium about 700 BC. All of the base metals are known to have been produced in small quantities during the Colonial period in America, but perhaps the first commercial production was the iron ore shipped from Virginia to England in 1608, followed by lead in 1621. Among the earliest companies formed in America that still survive (according to the standard reference yearbooks), were: the Jackson Mining Co., predecessor of Cleveland-Cliffs Iron Co. on the Marquette Range, Michigan, in 1844; the Sussex Zinc and Copper Mining & Manufacturing Co., fore-runner of New Jersey Zinc Co. in 1848 (although the Franklin-Sterling body was discovered in 1640); the five companies, Pittsburg and Boston, Quincy Mining, Pewabic, Huron Mining, and Minesota all formed in the decade (1844-1855) that followed the rediscovery of Keweenaw copper, were combined into Calumet and Hecla; and Vermont Copper Mining Co. in 1853 Although southeast Wisconsin lead-zinc was discovered in 1690, Mine La Motte in southeast Missouri in 1720, placer gold in California in 1848, Comstock Lode in 1859, Leadville in 1860, Cripple Creek in 1891, no surviving companies of those early mining periods exist. The first strong producer in the Mississippi Valley was St. Joseph Lead in 1864; Homestake and Pickands-Mather, were formed in 1877, Phelps-Dodge in 1881; Pittsburgh Reduction, the predecessor of Al-

Jan 1, 1976

By P. J. Soltis

Direct as well as indirect evidence of a-phase ordering was found in a "near-a" type titanium alloy, Ti-8Al-1Mo-1V. The annealed alloy showed an anomalous decrease in second-stage creep rate at 950°F (510°C) and 47,500 psi. Anomalous increases were noted in initial yield stress after 500 hr creep exposure and in tensile strength after 1100 hr creep exposure. Debye-Scherrer X-ray diffraction patterns obtained on fine-grained polycrystalline speci-ment showed much line broadening and development of superlattice lines after 500 hr at 510° C. Examination with the light and electron microscopes failed to reveal phase changes in thermally exposed material, but detailed metallography is presented illustrating the plastic and fracture characteristics of the alloy. Electron-metallographic evidence is presented, however, which shows the nature of the nucleation and growth of ordered regions from the disordered a in annealed material. In the original phase diagram of the binary Ti-Al system constructed by Ogden et al.1 aluminum was shown to be soluble in a titanium over a wide temperature range at concentrations up to about 30 pct. Subsequently, a number of papers2-7 have appeared which indicate the existence of either intermetallic compounds and/or ordered phases in the a field up to 25 pct Al. In the most recent of these, Goldak and Gordon paw7 have determined unequivocally the ordered hexagonal D019 structure for Ti3Al in a 25 pct Al alloy. No superlattice lines were observed above 1112°F (600°C). Previously, the embrittle-ment encountered by Crossley and Carew4 in low- temperature heat treatments of binary Ti-Al alloys low in aluminum had been attributed to the appearance of a new phase in light micrographs. In the present work, direct as well as indirect evidence is presented showing the existence of a-phase ordering in what is essentially the binary Ti-8A1 alloy containing small percentages of the ß stabilizers molybdenum and vanadium, i.e., the "near-a" Ti-8Al-1Mo-1V alloy. Although Bohanek and Kessler8 have shown that this alloy has good stability at temperatures up to 1100°F (593°C), the present work shows instability at 950°F (510°C) where long exposure times were used. Light and electron microscopy proved very useful in revealing the mechanical behavior of ordered a and led to the conviction that ordered "near-a" alloys may have remarkably good properties and useful engineering applications.

Jan 1, 1965

By Robert Adams

Secondary or scrap materials appear at all stages in the industrial process and in a bewildering variety of forms, grades, and values. It is useful to begin analyzing them by dividing the broad concept of "Secondary Supply" into three parts First, the concept must encompass the stock, or pool, of secondary materials. In the process of satisfying his wants, man produces desired products from the materials and natural resources found around him. As long as the rate of production is greater than the rate of obsolescence of a given product, the total stock or pool of materials embodied in that product will increase in size This stock concept relating to secondary materials is directly analogous to the "resource" concept used for primary raw materials in the preceding chapter, and includes all materials embodied in existing products (Obviously, this excludes those materials which are destroyed in the consumption process, viz , fuel oil burned to provide heat.) Consumption of a primary material in a productive process tends to reduce the resource base of that primary material In direct contrast, however, the production or use of products increases the resource base of the secondary material. Thus, we find that a country which has no resource of a primary material can, by importing products that contain the material, build up a large enough stock to provide a basis for secondary recovery. The estimated growth of the pool of copper in use in the United States through 1967 is shown in Table 5.B.1.a The estimate of 39 3 million tons at the end of 1967 includes only technologically recoverable copper and is, therefore, somewhat less than the stock concept described previously, which does not distinguish between recoverable and unrecoverable material. Nevertheless, Table 5 B.1 does give an idea of how a nation's secondary resource of a material can grow over the years. A second aspect of the concept of secondary supply is the generation of secondary materials. This includes materials generated as scrap in production as well as the movement of a material out of the stock of existing products via wear, damage, or obsolescence The quantity of materials generated is usually either nearly or completely independent of the technologic capabilities and economic forces which prevail in the secondary recovery market.b The justifications for and the qualifications to this statement are considered later. The final aspect of the concept of secondary supply consists in the secondary recovery process It is at this point that the technologic and economic forces of the secondary recovery market become the controlling fac-

Jan 1, 1976

By Jasper L. Stuckey

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

Jan 1, 1948

By S. J. Aresco, George E. Keller, J. Visman

INTRODUCTION The accurate sampling of coal, as with most minerals, is a difficult task. Coal is a very heterogeneous material made up of different types of coal and varying amounts of mineral matter. The product as mined may contain all of the layers of coal and impurities found in the seam as well as portions of the strata above and below the coal seam. The preparation plant is the device to size, crush and/or remove impurities so that the coal may be shipped as a saleable product. Sampling may be needed at many stages in the preparation process. Although this chapter is mainly concerned with sampling in connection with preparation processes, the principles will apply to all coal sampling. The main reasons for sampling in connection with coal preparation are: 1. To determine the washability characteristics of the raw coal by means of float and sink tests. These may be used for the design of a preparation plant, prediction of results to be obtained or for monitoring raw coal delivered to the plant. 2. To check the performance of various operating units in the plant, either by float and sink tests or chemical analyses. 3. To determine the analytical characteristics of the products produced, such as moisture, ash, Btu, sulfur, etc. HISTORY The earliest accepted methods of sampling coal in the United States were given in U. S. Bureau of Mines publications by J. A. Holmes,1 G. S. Pope2 and A. C. Fieldner.3 The American Society for Testing and Materials more or less adopted the methods proposed by the U.S. Bureau of Mines in their Standard D-21-1916, and it remained a standard for many years. Briefly, the standard called for a 500 pound sample for coals less than. 3/4 -in. in size and a 1,000 pound sample for all coals over ?4 -in. in size. No mention was made of increments but there was an instruction that the sample should spread over the coal to be sampled. Sample preparation was by hand crushing with the alternate shovel method for reduction to 250 pounds followed by coning and quartering below 250 pounds. Obviously, with the amount of work involved, this method of sample preparation was rarely followed. This method of preparation resulted in samples that were practically air dried because of long exposure while crushing, shoveling and quartering. In the late nineteen twenties and early nineteen thirties, studies for more practical methods were begun. Dr. E. S. Grummell4, Imperial Chemical Industries, Ltd, London, summarized the work to date at the

Jan 1, 1968

By O. W. Simmons, L. W. Eastwood, C. M. Craighead

Eighty-four quaternary titanium-base alloys from the following systems were investigated: 1. Titanium-chromium-carbon-nitrogen. 2. Titanium-chromium-carbon with copper, vanadium, molybdenum, manganese, iron, or nickel. 3. Titanium-chromium-nitrogen with vanadium, molybdenum, or nickel. The tensile properties, minimum bend radii, hardnesses, response to heat treatment and aging treatment, and phase relationships of these alloys are reported. HIS paper is the third in a series describing J- titanium-base alloys. The first paper describingdescribed titanium binary alloys, and the second contained data on a large number of titanium ternary alloys. Eighty-four heats, comprising three groups of quaternary titanium-base alloys, are described in this paper as follows: 1. Titanium-chromium-carbon-nitrogen alloys. 2. Titanium-chromium-carbon alloys containing copper, vanadium, molybdenum, manganese, iron, or nickel. 3. Titanium-chromium-nitrogen alloys containing vanadium, molybdenum, or nickel. The methods of preparing, fabricating, and testing the alloys are described in the paper Binary Titanium Alloys. Quaternary Titanium - Chromiurn - Carbon -Nitrogen Alloys The properties of titanium-chromium-nitrogen and titanium-chromium-carbon ternary alloys have been described in the paper Ternary Alloys of Titanium. Because small amounts of nitrogen and carbon both appear to be somewhat beneficial, these additions have been investigated fairly completely in quaternary alloys containing chromium at the following levels of composition: 2.5, 3.5, and 5.0 pct chromium 0.25 and 0.5 pct carbon 0.1 and 0.2 pct nitrogen Mechanical Properties: The mechanical properties of these alloys are listed in table I. Fig. 1 and 2 show graphically a comparison of the tensile properties and hardnesses of quaternary alloys with those of the titanium-chromium binary alloys. Fig. 1 shows the comparison at 0.25 pct carbon, whereas fig. 2 shows the comparison at 0.5 pct carbon. It is concluded from these data that 0.25 pct carbon and 0.1 pct nitrogen are desirable additions to the 5 pct chromium-titanium base. It is further concluded that most of this improvement is produced by the nitrogen and that carbon is either harmless or mildly beneficial, at least up to 0.25 pct. Structure and Transformation Range: The effects of carbon and nitrogen on the transformation range of the titanium-chromium alloys were determined as part of the routine investigation. Additions of 0.25 pct carbon and 0.1 pct nitrogen had no appreciable effect upon the transformation range. However, the addition of 0.25 pct carbon and 0.2 pct nitrogen definitely raised the beta solvus temperature, as shown by fig. 3.

Jan 1, 1951

By W. D. Robertson, E. Scala

Electrical resistivity of a number of pure liquid metals and alloys has been measured as a function of temperature and composition. The data show a close correspondence between the liquid and solid states with respect to thermal, structural, and compositional relationships. STUDY of diffuse scattering of X-rays by liquid metals1 has demonstrated that some degree of order persists above the melting point and that the atomic constitution of liquids is more analogous to the solid state than to a gas. Consideration of the change in various thermodynamic properties that accompanies transformation from solid to liquid leads to the same general conclusion.² evertheless, specific knowledge of the constitution of the liquid state is limited when compared with that of the solid and gaseous states owing, in part, to the difficulty of interpreting the X-ray data and in part to the indirect character of deductions based on thermodynamic data. Of the structure-sensitive physical properties, electrical resistivity of liquid metals is perhaps the most easily interpretable, particularly when comparison is made with the solid state. According to the available data, most of which was obtained prior to 1914, cubic metals exhibit a normal linear and positive temperature dependence in the liquid state and the data have been accepted without question. The divalent metals, zinc and cadmium, are apparently exceptional in that resistivity is not linear with temperature and it passes through a minimum. Mercury also exhibits a nonlinear temperature dependence but the slope is always positive. Important comparisons with magnesium could not be made at the time the following work was undertaken because the necessary experimental data were not available. Data on liquid solutions are very limited and are largely from a single source."-" Based on Bornemann's work, Norbury7 pointed out that the resistivity of liquid copper alloys appeared to be dependent on the valence of the solute and that the increase due to the solute was of the same order as in the solid state. However, large extrapolations were involved and no quantitative relationship was developed. Therefore, before proceeding with additional deductions regarding the resistivity of liquid metals and interpretation in terms of structure, it appeared necessary to verify and extend the previous work with particular emphasis on divalent metals and the effect of alloying elements of different valence in dilute liquid solutions. The present work includes: 1—A determination of the resistivity of high purity liquid magnesium, tin, indium, copper, zinc, and cadmium as a function of temperature. 2—The effect of 1 atom pct of copper, cadmium, aluminum, tin, antimony, and

Jan 1, 1954

By Enid C. Plante

This paper deals with the flotation of the mineral fluorite (calcium fluoride) and of two associated gangue minerals, calcite and quartz. The aim of the investigation was to produce "acid-grade" fluorite, which must contain less than one per cent of silica. Several reagents are used successfully in practice for floating fluorite from its ores. Oleic acid is the most widely used collector, usually at temperatures above 60°C, with sodium silicate as a dispersant for quartz and quebracho or tannin to depress calcite. Sulphides (e.g., galena) are often removed first by xanthate flotation. Many investigators23 report results in which more than 80 pct of the fluorite is recovered in a concentrate assaying 96 pct or more of fluorite and less than I pct of silica. This investigation was undertaken with the intention of floating the gangue, which is the minor constituent of the ore, from the fluorite. Hence emphasis was first placed on the cationic compounds that float quartz. No satisfactory separations were obtained in this way, and other reagents were investigated to discover whether these were more effective than oleic acid in floating fluorite from quartz in the usual way. The first part of the paper describes experiments with several long-chain collectors available commercially. Most of this work has been by captive-bubble and cylinder flotation tests, with some batch tests in a flotation machine. The second part describes the use of sodium cetyl sulphate as a collector for fluorite and includes laboratory tests and extension of the work to batch tests in the flotation machine. A method for determining the adsorption of sodium cetyl sulphate on fluorite has been developed and is described. Theory of Collection by Paraffin-chain Salts It may be assumed that these compounds are adsorbed at the mineral surface in one or more of three ways outlined by Kolthoff:12 1. Exchange adsorption between lattice ions in the mineral surface and collector ions in solution. Closely related is adsorption by the collecting mechanism postulated by Taggart,17 in which there is metathesis between the collector and the mineral cation or anion. 2. Exchange .adsorption between adsorbed gegen ions (p. 67, ref. 19) and collector ions in solution. 3. Adsorption of nonelectrolytes (polar-nonpolar) without displacement of adsorbed ions. With cationic collectors, inorganic cations in the solution (e.g., hydrogen ion) compete with the collector ions and therefore act as depressants, while inorganic anions have the same effect with anionic collectors. From this follows the general conclusion that ions of the same charge as

Jan 1, 1949

By Jasper L. Stuckey

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

Jan 1, 1948