Search Documents

By Ilmar Stöckel, Gösta Harlin, Agne Rustan

INTRODUCTION This chapter is a continuation of the studies by Rustan and Stockel (1979, 1980) on techniques for automating ventilation in Swedish mines and construction works. The studies have been financed by the Swedish Board of Technical Development. As a result of the studies it has been recommended that a good solution to diesel exhaust emission would be automatic, step by step control of the fans near the working place. Diesel vehicles are the major polluters underground in the mines. Therefore, we have suggested that diesel vehicles regulate the fans The goal of the continued study has been to find a way for active diesel vehicles to start and stop gallery fans at both intake and return air. In this paper different methods for activating fans are discussed. The best methods are chosen and tested in the mine. In this study we have found that change of temperature is an inexpensive and effective way to start and stop crosscut fans in sublevel caving and radio signals seem to be an attractive system for starting and stopping gallery fans . This work has been done in close collaboration between LKAB in Kiruna and the University of Luleå, Divisions of Electronics and of Mining and Rock Excavation. An advisory group for the project has been established with ventilation experts from the mines, representatives of the local mine workers' unions, and authorities from the local offices of Governmental Inspection of the Workers Safety. VENTILATION SYSTEM STUDIED In the project the ventilation system at LKAB in Kiruna was studied. The mining method used is sublevel caving with 9-13 m slice height. The air above ground is heated in winter by hot water and the main fans push the air down to a main distribution level along the 4000 m long and about 100 m wide ore body. From the distribution level, air is taken through shafts down to the sublevels, where it is pushed through the levels by local gallery fans on both the intake and return sides, Fig. 1.

Jan 1, 1981

By Burt Hartmann

The nation's ever-expanding construction and mining activity has placed an increasing demand upon engineers and geologists to design and construct stable slopes in earth materials-soil and rock. Man's attempt to handle these slope stability problems has been based primarily on practical experience and the resulting theories formulated to explain the phenomena. Too many instances occur when man is faced with a slope stability problem that has not yet been experienced and doesn't lend itself to solution by any existing theory. At this point he must extend himself in using his engineering judgment to arrive at a reasonable and safe design. As past experience has shown, all of the "safe designs" are not really safe. Sometimes they result in embarrassing failures. Measurements provide the key to understanding and controlling natural phenomena. We cannot hope to gain control of the slope stability problem until we understand the causes of slope failure, their behavior with respect to time and their relative magnitudes. Measurements required for an adequate definition of any slope problem must be of the highest reliability because of the importance of decisions which must be based on them. For this reason, direct measurements of movement, shear strength, water pressure, etc. of the unstable mass are preferable to indirect measurements of other physical properties. Movement instruments which can be positioned inside of the slope mass (within boreholes) are among the most useful in diagnosis and/or monitoring of slope movements. The higher the sensitivity and il-measurement precision possible with borehole instruments, the quicker the required information can be obtained and the more exactly may hazardous conditions be observed. A high density of measuring points in a single drill hole is deemed essential for diagnostic purposes. Behavior gradients may thus be obtained. The Pressure Meter (Fig. 1) can be used to measure a relative strength

Jan 1, 1968

By L. F. Stutzman, George Thodos

The friction factor plot presented by Cornell and Katz4 and developed for the flow of fluids through consolidated formations has been directly adapted for handling fluid flow problems involvitrg both linear and radial flow. In this adaptation the friction factor plot is used directly for the solution of problems and thereby eliminates the use of conventional equations which are specific to laminar (Darcy) or turbutent flow. This upproach overcomes the disadvantages inherent in the use of these conventional equations. It eliminates the necessity of checking the type of flow occurring in order to identify the specific equation which must be used. In radial flow problems, because of the increasing mass velocity of the fluids as they approach the wellbore. the type of flow may no longer remain laminar. Consequently, it is necessary to use more than one equation in a problem and to identify the range over which each equation should be applied. Finally, in practice it has been found that much of the flow of gases through consolidated media occurs in a range that is neither laminar or turbulent. For this transitional region, no convenient equations are available. The method and presented friction factor plot are appficahle to both liquids and gases. INTRODUCTION The flow of fluids through unconsolidated media in packed beds has been treated extensively by a number of investigatorsl,2,3,5,7,8 Most of these studies present friction factors as a function of modified Reynolds number similar to those developed for conventional fluid flow through pipes. These friction factor plots are presented for linear flow; however, Elenbaas and Katz have extended these concepts to apply to radial flow. All of these studies on unconsolidated materials require a knowledge of packing properties such as sphericity. porosity, and particle diameter. Sphericity and particle diameter cannot be defined at the present time for consolidated formations such as those commonly found in gas or oil reservoirs. As a result many investigators have not utilized friction factors and Reynolds number in the study of fluid flow through consolidated media. However, Cornell and Katz4 present a plot (Fig. 1) for the flow of fluids through consolidated porous media, in which the friction factor defined as: The turbulence coefficient, P, is related to the formation permeability, K, as presented in Fig. 2. Three different types of flow may exist in the flow ot

Jan 1, 1957

By C. C. Koch, M. L. Picklesimer

PHYSICAL metallurgists interested in the alloying behavior and phase transformations in rare-earth metals and alloys require a strain-free polished and etched surface for both metallographic and X-ray examination. However, the rare earths have presented a problem in this respect since they are difficult to polish free from strain and are very reactive to the atmosphere. Their tendency to oxidize readily even at room temperature necessitates careful preparation and rather elaborate protection if their surface is to be examined for any length of time. The "light" lan-thanides (i .e., atomic numbers less than 63), especially lanthanum and cerium, are particularly bad in this regard; they oxidize very rapidly at room temperature. To eliminate the problem of plastic deformation remaining on the surface after mechanical polishing, electropolishingl and chemical polishing techniques2 have been developed. The electropolishing technique requires the specimen to be immersed in an electrolyte at -77°C and thus obviates a metallographic study of, for example, the fcc —double-hexagonal close-packed (dhcp) transformation in cerium which begins at -10°C. The chemical polishing solution has been used only on several of the "heavy" rare-earth metals. However, a convenient method for protecting the polished and etched surfaces from atmospheric corrosion has not been available. Our interest in the superconducting properties of lanthanum, and in the phase transformations in lanthanum and cerium, has led us to develop a technique for the metallographic preparation of lanthanum and cerium which clearly reveals the microstructure and preserves the etched surface for days. The specimens are chemically polished and anodized. The chemical polishing is performed at room temperature, the anodic oxide film provides the required protection from the atmosphere, and colors produced in the film provide a simple positive technique for phase identification. Lanthanum and cerium metal ingots obtained from Johnson Matthey and Co., Ltd., were remelted to suitable shapes and heat-treated to produce various microstructures. The samples were placed in epoxy mounts and, after a small hole was drilled in the back of the mount for electrical contact, were ground on silicon carbide

Jan 1, 1968

By J. G. Hall

Introduction When one thinks about world metal economics today, it seems to me he must go beyond the traditional factors such as exploration, discovery, economic feasibility of development, management, labor, and the application of technology. These elements have been and will continue to be very important, of course, in making available the resources that experts believe the world will require during the remainder of this century. There are, however, some new forces as well as new or different emphasis on some of the old factors that could materially affect the development of the world metal mining industries. For example, in my own company two of the most significant considerations affecting our economics today have to do with foreign political decisions and with environmental concerns here in the U. S. -both of which play a far more significant role in our economic considerations than they did as recently as 10 years ago. After a brief look at some historical data and some projections of probable future demands for the world's major metals, I shall then identify and comment upon some of the factors that I believe will have an increasing impact on the future of the economics of our industries. I do not have any magic solutions to the problems we will face; nevertheless, we in the mining industries of the world are going to have to cope with these matters and find satisfactory answers to the problems they will create. The Past Although the age in which we live has been described as the atomic age, the space age and the computer age, we are, in fact, living in a metals age, and we have lived in a metals age for a very long time. The discovery of copper smelting, for example, is placed at about 4000 B.C. Gold was used in a primitive way before that. Other metals - lead, silver, tin, iron and mercury - were discovered and used before 2000 B.C. In all probability, we will be dependent upon metals beyond the vision of anyone living today. In industrialized nations of the world, man's mode of living is based to a great extent on metals, and it is extremely unlikely

Jan 1, 1971

By C. S. Smith, E. W. Palmer

For several years an investigation has been in progress in the research laboratory of The American Brass Co. to determine the thermal and electrical conductivities of most copper alloys of commercial importance and several of scientific interest. This paper contains such data on the binary alloys of copper with silicon, aluminum, manganese and nickel, and on a large number of ternary or more complex alloys. Some interesting general relationships between the thermal and electrical conductivities for all copper alloys at all temperatures are pointed out. The data for the copper-zinc, copper-phosphorus and copper-tin binary systems have already been published1,2 † except for the electrical conductivity at 200" C., which is given in the appendix of this paper. Literature on Thermal Conductivity of Copper Alloys The papers referred to above contained a summary of the figures available in 1929 for the thermal conductivity of copper alloys. There is given in Table 1 herewith a selection of the data that have appeared since that time. The measurements of Hanson and Rogers3 are particularly interesting since they cover a series of alloys in the alpha solid solution range and show the effect of heat-treatment. Their alloys were tested as annealed castings, and are not therefore directly comparable to the worked alloys measured in the present investigation, although the difference is small. Bailey's determinations4 were carried out on the alloys used by Lees6 in 1906, and extend his results to higher temperatures. It is most unfortunate that the alloys were not analyzed, for the approximate compositions given are hardly sufficient identification of the material. It is equally to be regretted that neither Hanson and Rogers nor Bailey give data for the electrical conductivities of their samples. Sager6, using the heat-wave method of King, determined the thermal conductivity of copper, nickel and four alloys of the two metals. His results are included in Table 1.

Jan 1, 1935

By C. S. Smith, E. W. Palmer

For several years an investigation has been in progress in the research laboratory of The American Brass Co. to determine the thermal and electrical conductivities of most copper alloys of commercial importance and several of scientific interest. This paper contains such data on the binary alloys of copper with silicon, aluminum, manganese and nickel, and on a large number of ternary or more complex alloys. Some interesting general relationships between the thermal and electrical conductivities for all copper alloys at all temperatures are pointed out. The data for the copper-zinc, copper-phosphorus and copper-tin binary systems have already been published1,2 † except for the electrical conductivity at 200" C., which is given in the appendix of this paper. Literature on Thermal Conductivity of Copper Alloys The papers referred to above contained a summary of the figures available in 1929 for the thermal conductivity of copper alloys. There is given in Table 1 herewith a selection of the data that have appeared since that time. The measurements of Hanson and Rogers3 are particularly interesting since they cover a series of alloys in the alpha solid solution range and show the effect of heat-treatment. Their alloys were tested as annealed castings, and are not therefore directly comparable to the worked alloys measured in the present investigation, although the difference is small. Bailey's determinations4 were carried out on the alloys used by Lees6 in 1906, and extend his results to higher temperatures. It is most unfortunate that the alloys were not analyzed, for the approximate compositions given are hardly sufficient identification of the material. It is equally to be regretted that neither Hanson and Rogers nor Bailey give data for the electrical conductivities of their samples. Sager6, using the heat-wave method of King, determined the thermal conductivity of copper, nickel and four alloys of the two metals. His results are included in Table 1.

Jan 1, 1935

US 4,133,866-Selective recovery of the bound sodium content of red mud obtained in the production of alumina by the Bayer process The red mud is mixed with aqueous ferric sulfate, the resulting suspension stirred intensively at a temperature of 15-85°C and adjusted to a pH value of from 4.4 to 4 6, and the solids are removed. The clarified solution of sodium sulfate can be used directly for the leaching of additional bauxite T Lakatos, M Miskei, J Szolnoki, F. Toth, and L Revesz, assigned to Aluminiumipan Tervezo es Kutato Intezet, Almasfuzitoi Timfoldgyar, and MTA Geokemiai Kutatolaboratorium. Jan. 9, 1979. 3 pp (423-208). Filed: 10¬28-77 (846,588) Priority: Hungary, 10-29-76 (AU 364). US 4,145,398-Continuous digestion of bauxite with aqueous sodium hydroxide, with higher throughput in existing plants or the construction of smaller plants with equivalent capacity The ore suspension at a solids concentration of 1-6% by weight and temperature of 200-300°C is flowed through a digestion tube or nest of tubes at a velocity of preferably from 2 to 5 m/s and under a pressure of from 10 to 200 atm Heat is supplied by a fluid heat carrier flowing in countercurrent in a concentric outer tube. Preferably, some of the red mud is recycled to the digestion operation. L. Plass, assigned to Vereinigte Aluminium-Werke A.G Mar 20, 1979. 5 pp. (423-121) Filed: 2-27-76 (754,749) Same: British 1,437,548, dated May 26, 1976 Same Canadian 1,008,253, dated Apr 12, 1977. US 4,146,573-An aqueous slurry of red mud, formed in the Bayer process production of alumina from bauxite, can be solidified by treating the red mud with a described quaternary ammonium salt, continuing mixing until the red mud has set up to a rigid mass, and recovering the solidified concentrated red mud J Kane, assigned to Nalco Chemical Co Mar 27, 1979 4 pp (423-82). Filed 8-2-78 (930,251).

Jan 1, 1980

By A. H. Grobe, F. N. Rhines

AT elevated temperatures the oxide of silver is unstable in the air at atmospheric pressure, consequently no external oxide scale forms upon pure silver under conditions of high-temperature annealing. When small quantities of certain alloying elements are present in the silver, the formation of a thin external scale is possible' and in addition there may form a subscale composed of the oxide of the solute element precipitated within the body of the silver. Norbury2 and Leroux and Raub3 have reported internal oxidation (subscale forma¬tion) in alloys of silver with 2, 7.5, and 30 per cent of copper. The presence of the subscale is believed to be responsible, at least in part, for the objectionable "fire mark" in Sterling silver.4 Several other alloys of silver, after oxidizing heat-treatments, are known to exhibit undesirable polishing characteristics that may be the result of internal oxidation. Except for the absence of an external scale of silver oxide, it is to be anticipated that silver alloys will prove to be very similar in their oxidation behavior to the alloys of copper, the oxidation characteristics of which have been studied in some detail5,6 The present research confirms this anticipation. The oxidation of a series of 20 dilute alloys of silver has been studied metallographically; some types of subscale not encountered among the copper alloys have been found. Instances of internal oxidation in alloys of most of the metals of the I-b and VIII groups of the periodic system are on record, but evidence of this type of oxidation in alloys of the metals of the intermediate groups is lacking. A number of the metals of the intermediate group, among them cadmium, lead, tin, and zinc, appear to provide the conditions essential to subscale formation; i.e., they form oxides with a relatively low negative free energy of formation, they dissolve other metals that form more stable oxides, and, presumably, oxygen will diffuse through them. In a study of 4o alloys of these white metals only a few cases of internal oxidation have been found. The probable reasons for this difference in behavior will be discussed presently. EXPERIMENTAL PROCEDURE Silver.-The silver alloys employed in the oxidation studies were prepared in heats of 30 grams each from high-purity silver (99.993 per cent Ag)* and the purest avail-

Jan 1, 1942

By W. K. Lewis

During the last decade the petroleum refinery engineer has made great progress in achieving a better understanding of the physical behavior of hydrocarbon mixtures, with particular reference to their pressure-temperature-volume relationships, the mechanism of the evaporation of liquids, the condensation of vapors, including the changes in composition, and the heat effects accompanying them. With the new insight into the mechanism of movement of oil and gas through the formations in which they occur, achieved by the production engineer, it is clear that the latter will need to utilize in the solution of his own problems much of the information outlined above. It is the purpose of this paper to outline the portions of that information that seem most certain to prove of importance in production work. Properties of Pure Hydrocarbons While it is true that petroleum always consists of highly complex mixtures of hydrocarbons, none the less understanding of the behavior of the mixture must be based upon a knowledge of the properties of the pure components. However, in view of the tremendous number of hydrocarbons existing in petroleum, the determination and formulation of the properties of all of them would seem a discouraging task. The difficulty of the situation is increased by the undoubted facts that the overwhelming majority of chemical individuals in petroleum have never been isolated as pure compounds, none of their physical properties have been determined and even their chemical constitution is unknown. The situation would be hopeless were it not for the fact that certain extraordinary correlations of important properties of various hydrocarbons have been discovered which make it possible to predict those properties for a given chemical individual on the basis of a very limited characterization of it. Thus one can predict the vapor-pressure curve of an unknown hydrocarbon over a considerable range from the knowledge of a

Jan 1, 1934

By Oliver C. Ralston, James E. Norman

SEPARATION of minerals by froth flotation is rightly called an art. It can truthfully be said that no two ores separate in the same way. The difference in results obtained when natural and synthetic mixtures of minerals are separated is so great that such tests frequently have been worthless in attempting to select conditions in which a natural mixture will separate. With a few rare exceptions, the natural mixture is much more difficult to treat than a synthetic mixture, and a much poorer separation is obtained. Perhaps several experimenters have wondered why 10 or 20 per cent of a mineral being floated from an ore does not float and is different from the 90 or 80 per cent that is recovered. In experimental tests on pure sphalerite, observers1 have noted that varying amounts of sphaIerite may be froth-floated with pine oil alone, the amount recovered in the froth depending apparently upon the source of the sulphide. The only explanation of results such as these, barring insufficiency of frother or time of flotation, is that the surface of the mineral floated is different from that of the mineral depressed. This difference often has been found to be caused by natural contamination of mineral surfaces, apparently brought about by weathering and exposure to natural solutions. There is virtually no rock that is absolutely unweathered. One of the writers had an exceedingly instructive experience in 1931 while working with United Verde copper-zinc iron sulphide ore in Arizona. Nonselective flotation of chalcopyrite and sphalerite away from some of the pyrite was all that could be accomplished. All known depressants produced only slight effect. Sodium cyanide showed some effect, but so much had to be used that only a small amount of chalcopyrite could be

Jan 1, 1939

By A. D. Zunkel, A. H. Larson

Equilibrium arsenic contents of Pb-As alloys in contact with PbO-As2O3 slags containing less than 30 mol pct As2O3, were determined at 650°, 700: and 750 C in an inert at?rzosphere. In this temperature range, the arsenic content of the alloy increased with increasing temperature in the single-phase liquid slag region and decreased with increasing temperature in the two-phase slag region and the single-phase solid-solution slag region. The PbO-As2O3 phase diagram below 22 mol pct As2O3 was determined by thertrzal analysis and by application of a log ?As2O3/?PbO vS log XAs2o3 /x3pbO plot determined from the equilibrium actiuity data. The resulting phase diagram was not well-defined since the eutectic temperature was not detected in the thermal analysis experiments, although a region of terminal solid solubility of As2O3 was found. Results from the phase diagram determination are compared with an existing diagram in the literature. THIS experimental investigation is an extension of a study by the authors1 on the slag-metal equilibria in the systems concerned with commercial lead refining processes such as softening and dross fuming. The first part of this investigation was a study of the slag-metal equilibria in the Pb-PbO-Sb2O3 system. The only experimental work previously done on the Pb-PbO-As2O3 system was by Pelzel2,3 in which the phase diagram for the PbO-As2O3 system was determined below 50 wt pct As2O3 and the equilibrium constant for the reaction 3Pb + As2O3 + 3PbO + 2As was determined as a function of temperature. No slag-metal equilibrium data have been determined. It is due to the scarcity of information regarding the Pb-PbO-As203 system that this work was undertaken. This paper describes the determination of the slag-metal equilibria in the Pb-PbO-As203 system by equilibrating Pb-As alloys with PbO-As2O3 slags in an inert atmosphere, the effect of 1 wt pct additions of bismuth and copper on the slag-metal equilibria, and the PbO-As2O3 phase diagram both by thermal analysis and the use of the slag-metal equilibria data. EXPERIMENTAL Materials. The materials used in this investigation were analytical reagent-grade and assayed as follows: 1) 99.8 pct PbO (0.014 pct insoluble in CHJCOOH, 0.02 pct not precipitated by H2S, 0.1 pct CaO, and 0.08 pct SiO2); 2) 99.95 pct As2O3; 3) 99.99 pct Pb; 4) 99.0 pct As; 5) 99.99 pct Cu; and 6) 99.97 pct Bi. Room-temperature X-ray patterns revealed no detectable impurities in any of these materials. Apparatus for Equilibrium and Thermal-Analysis Determinations. The resistance-heated crucible furnace used in this investigation employed nichrome elements and was mounted so that it could be raised to surround the reaction tube during each experiment and, subsequently, lowered. A schematic diagram of the apparatus is shown in Fig. 1. Each charge was heated in a 3+-in.-OD by 31/2-in.-high 416 stainless-steel crucible placed in a 41/4-in.-1D by 18-in.-long fused-silica reaction tube which was closed at one end. On a shoulder around the crucible was placed a 3: -in.-OD by 12-in.-long open-end fused-silica condenser tube. The open end of the reaction tube was covered by a water-cooled brass cap with ports for 1) admitting an inert atmosphere to the system through a stopcock, 2) introducing a stainless-steel, motor-driven, paddle stirrer into the crucible, 3) evacuating the system with a mechanical vacuum pump, and 4) sampling the melt with Vycor sampling tubes. The brass cap was fitted to the open end of the reaction tube with a silicone gasket and collar clamp. The furnace temperature was controlled by a Barber-Coleman Capacitrol controller and a chromel-alumel thermocouple. Due to the corrosiveness of the melt, the controlling thermocouple also served as the measuring thermocouple. The temperature of the melt was calibrated against the controller temperature and was checked periodically during each test with a Vycor-enclosed calibrated chromel-alumel thermocouple. The temperature measurement and control can be considered accurate to ±3°C. Procedure. The charge placed in the crucible for each experiment consisted of 1000 g of Pb-As alloy and 300 g of PbO-As2O3 slag. The crucible was then placed in the reaction tube, the condenser tube was placed on the shoulder of the crucible, the silicone gasket and brass cap were fitted on the open end of the reaction tube, and the entire system was evacuated and filled with argon ten times. After the last flushing, a positive argon pressure of 1 psig was impressed on the system. The furnace was then raised to sur-

Jan 1, 1968

By G. P. Bowman, D. F. Howard, R. K. Saxer, J. R. Myers

This study was undertaken to redetermine the phase diagram of the lead molybdate-bismuth molyb-date salt system. A portion of this diagram was originally determined by Zambonini in 1920, and more recently by Beale. Thermal analysis and X-ray methods were used to define this system. The diagram was found to be a simple eutectic type with an eutectic at 11 mol pet lead molybdate and 634OC. A maximum solid solubility of 6 mol pet was found at the lead molybdate end of the diagram. Solid solubility at the bismuth molybdate end of' the diagram appeared to be quite limited and possibly nonexistent. These results generally agree with those of Beale, but differ significantly from those of Zambonini. MOLTEN salt systems have been vigorously investigated since World War 11. Much of this work has been performed as pure research; however, consideration has recently been given to their possible use as coolants in nuclear reactors. Because of this application and other potential applications, it was decided to reinvestigate the lead molybdate-bismuth molybdate phase diagram. This diagram was originally determined by Professor F. Zambonini of the University of Turin in 1920.' In 1961, a portion of this diagram was redetermined by Beale.2 With the quality equipment and high-purity materials available today, it was expected that discrepancies between the results of this present investigation and Zambonini's work would be obtained. This investigation was conducted in two parts. First, the general shape of the phase diagram was determined by cooling-curve analysis. Next, the primary solid-solution phase at the lead molybdate end of the diagram was investigated by means of X-ray diffraction techniques. EXPERIMENTAL PROCEDURE High-purity lead molybdate, assaying 99.993 pet, and high-purity bismuth molybdate, assaying 99.989 pet, were employed during this investigation.* The results of a spectrographic analysis of the two salts are presented in Table I. Twenty-two experimental compositions were prepared for cooling-curve analysis. Compositions selected are presented in Table 11. Several randomly selected samples were analyzed chemically to check that the compositions of the prepared specimens were within the limit of

Jan 1, 1964

By Fred H. Klaer

Water supplies dependent upon induced infiltration can be developed by vertical wells, by infiltration galleries, or by horizontal water collectors. Each method is described and the advantages of water obtained by induced infiltration with respect to cost, chemical quality, and temperature are shown by specific water supplies. THE subject of ground water in industry is assuming increasing importance as new processes and new industries are developed. Industrial specifications of chemical quality and temperature for process water and for cooling purposes are becoming more rigid, and water must now have many properties to meet these requirements. As ground water is usually more constant in quality and temperature, many industries are turning to ground-water supplies to satisfy their growing need. As many published articles have stated during the past several years, the ever increasing demands have caused shortages of water supply in many localities throughout the United States. Although such shortages are generally of a local nature, they have given rise to many attendant problems, such as increased pumping costs, salt water encroachment, and rising ground-water temperatures. One partial solution to the problems of overdevelopment of the ground-water reservoirs in many areas can be accomplished by developing ground-water supplies that are dependent upon induced infiltration and by planning the use of underground reservoirs. These reservoirs can be filled during periods of excess precipitation and stream flow and can be emptied during periods of drought, in a manner similar to the use of surface reservoirs. In this way water that otherwise would be wasted into the oceans is salvaged during periods of excess. The development of water supplies dependent on induced infiltration is a relatively new concept and should be defined. When a well is pumped, the water level around the well is lowered in the shape of an inverted cone or cone of depression. As pumping is continued, the cone of depression will continue to expand, horizontally and vertically, until the quantity of water crossing the perimeter of the cone plus the recharge within the area of the cone is equal to the quantity of water being pumped.

Jan 1, 1954

By P. M. Budge, William L. Fink, Kent R. Van Horn

The investigation of the phase relations of high-purity aluminum-base alloys is a part of the fundamental research program of the laboratories of the Aluminum Company of America. The results of a number of binary and ternary systems have previously been published in the Transactions of this society. The aluminum end of the binary aluminum-titanium system has been studied. This system has received relatively little attention. To the authors' knowledge, there are two previous papers on this subject. E. van Erckelensl determined the constitutional diagram reproduced in Fig. 1. According to this diagram, the liquidus represents the separation of TiA14, (Ti = 30.7 per cent.). He concluded that this is the composition of the compound, because in his work the eutectic horizontal terminated at 30.7 per cent. titanium and the metallographic examinalion of a sample of this composition revealed only one phase. According to the constitutional diagram developed by W. Manchot and A. Leber,² reproduced in Fig. 2 from data given in their article, the liquidus represents the separation of the compound TiA13 (Ti = 37.2 per cent. ). The composition of the compound was derived in a manner similar to that utilized by van Erckelens. Moreover, Manchot and Leber confirmed the composition of the compound by analysis of the constituent left as a residue after dissolving the alloys in weak sodium hydroxide solution. Although these are the only publications describing the constitution of the system, other investigators have studied the composition of the titanium compound. L. WÖhler3 says that there is a compound TiA13 which was later confirmed by W. Manchot and P. Richter4 and by

Jan 1, 1931

By Robert Anderson

DURING the past 5 years no subject has aroused more interest or received more attention among mill operators than flotation. One reason for this is, undoubtedly, the remarkable success of the process in Australia where that country has risen to the position of furnishing one-fifth of the world's Supply of zinc. The plant of the Butte & Superior Copper Co., designed by James M. Hyde in 1912, was the first important large flotation plant in this country; other installations have been made since then with considerable frequency, particularly so in the last 2 years. Without going into complete detail, it may be safely said that although flotation is a highly successful commercial process, it is more or less on an empirical basis. Upon scanning the literature, it is found that the flotation investigations have, in the main, dealt with a solution of the problems which accrue to practise; until recently no attempt was made to remove the difficulties in the way of the formulation of a consistent and harmonious theory. Of late this phase of the work has been receiving considerable attention, particularly by the United States Bureau of Mines at its Salt Lake City station, by the Mellon Institute at Pittsburgh, by the General Engineering Co. at Salt Lake City, by many of the mining schools, and private individuals almost ad infinitum. There is, at present, an enormous amount of laboratory work being carried on in flotation research, and probably the time is not far away when a generally acceptable explanation of flotation phenomena can be Set forth. However, at this time, it seems as though the current technology is befogged with a super-abundance of contradictory evidence; this confusion can only be dispelled as time proceeds and the knowledge of the subject becomes more complete.

Jan 7, 1916

By Louis C. McCabe

The control of dusts and fumes of submicron size is involved in many process industries. This paper presents in tabular form the quantitative data from a number of metallurgical operations and discusses allowable discharge in terms of effluent-weight ratio. Typical installations for recovery of stack effluents are cited. THERE are many sources of smoke, fumes, gases, and dusts that may cause undesirable contamination in an industrial area. Fumes and gases are the result of chemical action or volatilization, while dusts are produced in processes of disintegration and dispersion. Commonly, smokes are suspended particles formed by combustion or destructive distillation. Methods for controlling smoke are generally known, and great improvements have been made in equipment for removing fine dusts and fumes from gases. In most of the industrial centers of the country, the chief duty of the air-pollution abatement agency is the elimination or reduction of emissions resulting from improper combustion. Correct methods of firing, proper fuel selection, and installation of properly designed equipment may accomplish this. It is becoming more widely recognized that much of the contamination of an industrial atmosphere is caused by dusts, fumes, and gases that are not related to the process of combustion. As such emissions are usually a functional part of plant operation, they rarely can be prevented even by better design and careful operation. When dusts, fumes, and gases are an integral part of the operation, mechanical equipment must be designed to remove these emissions. Most of the dusts and fumes that should be controlled are less than 1 micron in size. Control of such small particles is largely a new and untried field in many industrial areas. However, where conditions have been critical, effective control equipment for dusts, fumes, and gases has been in operation for many years. The problem is not one of smoke abatement and requires an entirely different set of standards for effective solution. Identical standards need not be applied to all industrial areas because of differences in meteorology, physiography, plant location, plant density, and nature of stack effluents. In this paper, discussion of control of atmospheric contamination by industrial plants refers specifically to the Los Angeles area, but the method of approach is applicable to any area where similar problems are encountered. Quantities of particulate matter reported in analysis of stack effluents indicate the need for standards of emission. Many types of dusts and fumes that contribute materially to the air-pollution problem are discharged into the atmosphere at a lower rate than 0.40 grain per cu ft at standard conditions. On the other hand, some stacks discharge at a higher

Jan 1, 1951

By Louis C. McCabe

The control of dusts and fumes of submicron size is involved in many process industries. This paper presents in tabular form the quantitative data from a number of metallurgical operations and discusses allowable discharge in terms of effluent-weight ratio. Typical installations for recovery of stack effluents are cited. THERE are many sources of smoke, fumes, gases, and dusts that may cause undesirable contamination in an industrial area. Fumes and gases are the result of chemical action or volatilization, while dusts are produced in processes of disintegration and dispersion. Commonly, smokes are suspended particles formed by combustion or destructive distillation. Methods for controlling smoke are generally known, and great improvements have been made in equipment for removing fine dusts and fumes from gases. In most of the industrial centers of the country, the chief duty of the air-pollution abatement agency is the elimination or reduction of emissions resulting from improper combustion. Correct methods of firing, proper fuel selection, and installation of properly designed equipment may accomplish this. It is becoming more widely recognized that much of the contamination of an industrial atmosphere is caused by dusts, fumes, and gases that are not related to the process of combustion. As such emissions are usually a functional part of plant operation, they rarely can be prevented even by better design and careful operation. When dusts, fumes, and gases are an integral part of the operation, mechanical equipment must be designed to remove these emissions. Most of the dusts and fumes that should be controlled are less than 1 micron in size. Control of such small particles is largely a new and untried field in many industrial areas. However, where conditions have been critical, effective control equipment for dusts, fumes, and gases has been in operation for many years. The problem is not one of smoke abatement and requires an entirely different set of standards for effective solution. Identical standards need not be applied to all industrial areas because of differences in meteorology, physiography, plant location, plant density, and nature of stack effluents. In this paper, discussion of control of atmospheric contamination by industrial plants refers specifically to the Los Angeles area, but the method of approach is applicable to any area where similar problems are encountered. Quantities of particulate matter reported in analysis of stack effluents indicate the need for standards of emission. Many types of dusts and fumes that contribute materially to the air-pollution problem are discharged into the atmosphere at a lower rate than 0.40 grain per cu ft at standard conditions. On the other hand, some stacks discharge at a higher

Jan 1, 1951

Human engineering was the keynote of the thirty-ninth annual meeting of the American Society of Mechanical Engineers, which was held in New York, December 3-6. This note was sounded by President Charles T. Main in his address at the opening session and was carried through by all the speakers. In his survey of the year's work, he said that more than 6000 names of engineers were furnished the Government for filling a wide variety of positions. In addition to the 1400 members in service, two members of the council of the society are in uniform in France and one, as a distinct war service, is in charge of one of the largest shipyards. After giving other ways in which the Society has helped the Government, President Main called attention to the necessity for thoroughgoing efforts to increase production and the settlement of questions involving industrial relationships. At the following meeting, President Adams of the American Institute of Electrical Engineers called attention to the necessity of meeting labor in a progressive way, facing labor questions fairly and squarely, as the real interests of labor cannot be separated from those of the engineer. Charles E. Knoeppel, discussing "Industrial Organization as It Affects Executives and Workers," said the problem of the cost of living might be settled in two ways: 1, there must be more producers, and 2, there must be a greater amount supplied by those now producing. The first solution is practicable, he said, if labor is allowed shorter hours, better conditions, and a remuneration that will attract workers. The second can be employed by eliminating waste, standardizing conditions, setting fair tasks, and allowing men to earn an amount that will compensate them for' their skill and cooperation. Dudley R. Kennedy of Philadelphia, employment manager of the American International Shipbuilding Corporation, said the human-engineering phase of the country's industrial development had generally been overlooked. "We hardly yet know what competition means; we will learn it within a few years. Permit me to prophesy that the executive of the next decade will be the man who best knows men. He will be an originator, a handler of men as individuals, a handler of men in the mass, a leader not a driver, a very human man. The science of human engineering is here to stay. The study of human characteristics is the most enduring, as well as the most fascinating in the world, and still the most complex."

Jan 1, 1919

By Gerhard Derge

A SERIES of studies of the corrosion of tin is under way in the Metals Research Laboratory at the Carnegie Institute of Technology. The complete program includes examination of the corrosion properties of high-purity tin and the changes produced in these properties by the addition of varying amounts of alloying elements. Other studies of this subject have been made recently under the sponsorship of the International Tin Research and Development Council, but these researches have been confined largely to the weakly acid environments commonly encountered in the canning industry.1 There is little information available regarding the corrosion of tin under alkaline conditions, but such data would be of value, for a large amount of the metal is used under such conditions. The potential measurements to be described were made because they seemed to offer the most rapid method for obtaining a general view of the conditions to be encountered in such service. These experiments will also serve to establish a technique that will be of value in further studies. It must be emphasized that the results reported are those of controlled laboratory experiments and that the conclusions drawn cannot yet be applied to service conditions; rather, they point to the directions in which more exhaustive experimental work may be done to best advantage. EXPERIMENTAL PROCEDURE The first work was devoted entirely to the problem of obtaining reproducible results from a series of potential measurements. Only the methods finally adopted as standard will be described here, except when the variations from these have furnished results of interest. The cell used is shown schematically in Fig. 1. The electrolyte is contained in the vessel A (an inverted bell jar), whose ground top is fitted to the transite-board lid B. The controlled atmosphere can be admitted

Jan 1, 1938