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By A. D. Schwope, L. R. Jackson, K. F. Smith

Burghoff and Blank1 have pointed out that the creep properties of hard-drawn coppers are closely associated with their individual softening characteristics and have further shown that the creep resistance of various types of copper is improved, under certain circumstances, by cold stretching. In the design of certain types of electrical machinery, it is important to have the creep resistance as high as possible; furthermore, short-time creep strength is important since in many cases stresses are large only during warming-up and cooling-down periods. In this paper, data are presented showing the effect of cold work on the short time creep strengths of various types of commercial copper under several conditions. It is shown that trends from short-time creep tests are evident at longer times. Materials Used in the Investigation The coppers used in this investigation were commercial grade and of two basic types, oxygen free high conductivity (OFHC) and tough pitch. Additions of silver in amounts of 15 and 25 oz per ton were added to each of the two coppers. The analyses of these six coppers are given in Table 1. Originally, they started as wire bars 4 X 4 X 54 in. A. square rod was made by hot rolling the wire bars to 9/16-in. rod in 8 passes. This rod was then cold drawn to 0.445-in.-diam rod and annealed for 3 1/2 hr at 1000°F. It was then cold drawn to 0.325-in. rod and again annealed at 1000°F for 3 1/2 hr. Hard square rods were then made by cold rolling to 0.257 X 0.257-in. rod. Soft wire was made from the hard- drawn material by annealing at 650°F for 3 hr. The final rolling was performed using a set of 9-in. grooved rolls revolving at 30 rpm, which produced square wires. Reductions of approximately 5, 20, 30, and 40 pct were obtained using several passes in the same direction for the large reductions. The 5 pct reduction by drawing was accomplished using a steel die having 2 parallel bearing surfaces. The die angle was 7 1/2 degrees and the wires were lubricated with a paste of ceresin wax dissolved in carbon tetrachloride. The speed of drawing was 13 fpm. Since work was done on only two sides of the wire simultaneously, it was necessary to rotate it 90 degrees each pass to insure uniform deformation. The room-temperature tensile properties of the various tempers are given in Table 2. The grain size of the an- nealed 0.257-in. wires was uniform and averaged about 0.035-0.045 mm. Experimental Procedures for Short-time Creep Tests Standard creep-test frames (Fig 1) were used for the testing. Special fixtures were designed to apply axial compressive and tensile loads to the copper wires. The compression specimens were 1 in. long and the ends were ground flat and parallel. The creep in compression was indicated by the movement of reference marks s-ratched on intersliding platinum strips attached to the moving heads of the fixture. The movement was measured with an optical micrometer fitted with a filar eyepiece on which the smallest division was 0.00005 in. The tensile creep specirriens were 4 in. long which provided ample gripping surface for the jaw-type grips. The platinum strips were attached to a one-inch gauge length of the wire and the creep measured as previously described. The single-specimen furnaces were connected to individual power and control sources. The controlling equipment consisted of Foxboro controllers

Jan 1, 1950

By J. E. Stukel, J. Cocubinsky

A CONSIDERABLE amount of information is available on the equilibrium distribution of manganese between slag and metal under oxidizing conditions. These data have increased our knowledge of the manganese reactions in the open hearth, ladle, and ingot mold. In contrast, there is a paucity of data on the slag-metal distribution of manganese under reducing conditions. The purpose of the present investigation was to study the equilibrium distribution of manganese between blast-furnace type slags and iron saturated with carbon. Experimental Method Furnace: The induction furnace used for the experiments is shown in Fig. 1. A 1 in. pipe, attached to the transite cover, was fitted with a window through which the charge could be observed. Material could be introduced into the furnace through a tee and plug without removing the cover. A graph-it cylinder (3 in. ID and 10'/2 in. long), centered within the induction coil, was used as a heating element. During a test, a zircon plug kept the top of the furnace from becoming too hot from heat radiation. At the bottom, a graphite block on the vertical center line of the furnace and extending 1 1/2 in. into the coil, was used as a support for the graphite crucibles containing the melt. The graphite crucibles, machined from regular carbon electrode stock, had a 2% in. OD with 3/16 in. walls and were 5% in. long. The fumes present in the furnace during the early part of a run made optical readings uncertain. A noble metal thermocouple was, therefore, adopted to measure the temperatures. The arrangement used, shown in Fig. 1, allowed the silmanite protection tube to be replaced with a minimum effort. The thermocouple was calibrated against a standard Pt-Pt-Rh thermocouple in a fused quartz protection tube. The latter was inserted in the molten iron by removing the glass window on the cover. The lower couple was found to be very sensitive to temperature changes. To insure accurate temperature readings, the graphite crucibles were made to fit tightly against the silmanite protection tube. Further, to avoid contamination of the thermocouple by carbon, the silmanite tube was changed and the calibration procedure was repeated at frequent intervals. By using this temperature measuring technique, the furnace was easily held within *1O°C of the desired temperature. Because of the small free space in the furnace, no attempt was made to control the atmosphere. It

Jan 1, 1955

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Jan 1, 1923

By N. Van Wingen, Norris Johnston

Laboratory flood pot testing of California sands has progressed to a considerable extent in the past 18 months. Flood evaluations have been carried out on over 200 large core samples. Many of these were heavy oil sands of high permeability and completely unconsolidated in nature. The oil frequently formed a bank, though some of the oil was recovered in the subordinate phase of the flood, by viscous drag. Flood pot recoveries as high as 1400 bbl/acre ft have been recorded. Reservoir analysis suggests a conformance factor of 0.4 to reduce laboratory recovery to probable field practice. Oils with viscosities up to 1800 cp have been successfully handled in flood pot evaluations. The shallow, loose sands are not well adapted to the application of- high pressures to offset the high viscosities. INTRODUCTION Secondary recovery may be said to have started 60 years ago when accidental floods occurred in the Bradford sand in Pennsylvania. About 1921 artificially conducted water drives came into extensive use and since that time the great Bradford field has been almost completely subjected to water flooding. During the last 30 years, most of the known medium and deeper production in California has been discovered and is being exploited by primary recovery methods supplemented in some instances by high pressure gas injection. The California area is just beginning to feel the need for secondary recovery in view of an unprecedented market demand and the rapidly rising cost of new pool discoveries. With the presently recognized desirability of secondary recovery in California, there must also be appreciated a number of serious differences between the water flooding problems here as compared to the territory east of the Rockies. California sands are generally thicker, and are frequently soft and argillaceous. The oils are often heavier and asphaltic. Much of the oil is below 15°API, occurs at shallow depth, is cool and free from appreciable dissolved gas, which results in relatively high reservoir oil viscosity. Secondary recovery is particularly beneficial where primary recovery has been poor and where no natural water drive exists. These conditions apply particularly to the heavy, shallow, clean production from soft, often argillaceous California sands so abundantly found at depths less than 1500 feet. Often, too, there is a totally insufficient supply of water of satisfactory quality to inject at a reasonable cost. Also, the crude oils are priced far below the premium Bradford crude. Although these and a number of minor problems beset the operator desirous of starting secondary recovery, great progress has been made in the past few years in finding how to adapt previous Mid-Continent and Eastern experience to water flooding in California. There are about nine projects for subsurface injection of water which can be said to classify as secondary recovery operations. Subsurface water disposal would so classify when the sand receiving the water is a nearby oil producer, as is often the case. When water is injected subsurface into a barren sand, the operation does not classify as secondary recovery. Several of the most active operators avail themselves extensively of preliminary engineering and laboratory work to guide their decisions, while others enter small scale flooding operations directly in the field. It is the laboratory work pertinent to several of the California secondary recovery projects that this paper discusses. PURPOSES OF LABORATORY FLOODING TESTS Experience in areas where water flood operations have been carried out has indicated that careful engineering planning is an important requisite for subsequent economically successful field operation. Floods that fail are more frequently those where operations were instigated without a prior engineering investigation to determine the effectiveness of the injection fluid as an oil displacing medium. Laboratory data are essential in the evaluation of an oil property for secondary recovery possibilities. Success or failure of secondary operations can under certain special circumstances be determined directly by cores and their subsequent routine analysis. This is particularly the case where flushing of the cores in the course of coring is negligible and where the results of the analysis can be compared with existing secondary recovery operations. Where these conditions cannot be' fulfilled, the application of core analysis is more limited. In such event, the results obtained by water flooding core samples in the laboratory have been found to be of prime importance. Cores may be flooded "raw" as taken from the well or in the event flushing and depletion of the cores in the process of drilling are major factors the fluid content may be artificially restored prior to the flooding. Laboratory studies should also be made to determine the suitability of the water selected for injection. Thus interaction between injected and formation water may cause precipitates to be formed which may plug the sand. Even more important, especially to California operations, is the possibility of the hydration of formation clays by the injection water. The aims of flood pot and associated tests are basically to determine the residual oil saturation after flood, the water-oil throughput ratio and to establish whether an oil bank is formed. Additional information which can be obtained from flood pot tests pertains to the pressure differential required to effect displacement, the relative permeability to oil in the oil bank and the relative permeability to water in the watered out region behind the bank.

Jan 1, 1953

E. A. HOLBROOK,*Urbana, Ill.-To those who have followed the development of powdered coal two questions often occur. First, as to the moisture in the coal. In Illinois we recognize that the bituminous coals contain about 12 to 15 per cent. of what we call "contained moisture," that is, the moisture is present in the coal although this may appear absolutely dry and dusty. In addition, the surface moisture may be present in any amount. I would like to ask what is the relative effect of these two forms of moisture upon the work of pulverizing. Does Mr. Collins refer to the contained moisture or to the surface moisture in estimating the degree to which the coal must be dried? H. R. COLLINS.-In the lignite coals, of which this country possesses a great deal and is beginning to develop them to considerable extent, the "contained" or "combined" moisture does not .trouble us; we have no difficulty in reducing lignites to a high degree of fineness. But when dealing with bituminous, sub-bituminous, or semi-bituminous, we, prefer to reduce the combined moisture as well as the hydroscopic moisture as far as possible. We have recently put into operation, at a plant, furnaces and boilers consuming the lignite from northern New Mexico, which contains between 4 and 5 per cent. moisture as we pulverize and burn it. The evaporating efficiencies under the boilers have been so remarkable that we wish to check the results half a dozen times before quoting them. We have also just started two boilers at the Garfield smelter, and have obtained the same high efficiencies.

Jan 11, 1918

By T. V. Moore

DURING 1910, crude-oil production in the United States reached a record level averaging about 3.700,000 barrels daily. Export declined sharply while imports increased with the result that large quantities of crude oil were run to storage during the year. Imports consisted largely of residual fuel oil brought in from South America bit because of a shortage of that product in this country and of Mexican crude. The price of petroleum products followed the declining trend of the last three year resulting in serious disparity between crude and product prices. This condition was aggravated in some areas by the increasing production of distillate by recycling operations and by the high tanker rates prevalent in the last two months of the year. As a result two small purchasers found it necessary to reduce crude-oil price in the Corpus Christie area of Texas.

Jan 1, 1941

By Charles L. Bauer

WHEN a single crystal is annealed following plastic deformation recrystallization usually occurs rather than polygonization. Consequently, re-crystallization has received the overwhelming amount of attention albeit the intrinsic mechanisms by which dislocations rearrange and annihilate one another are just as well revealed by crystal polygonization. It is the purpose of this note to demonstrate the usefulness of studying the polygonization process by means of an etch-pit technique in sodium chloride. Sodium chloride deforms easily (the slip system is of the [110], (110) type), readily cleaves on (100) planes, and can be chemically etched so as to reveal the intersection of dislocations with a free surface. Thus it is possible to observe the distribution of dislocations after a crystal has undergone a specific deformation and annealing cycle. Various phases of the polygonization process

Jan 1, 1965

By H. R. Fife

AN extended study of dustproofing Freeport-seam coal has empha-sized several fundamental features in the successful treating of bituminous coals. The extent of the exposed surface area and its absorption proper-ties for the dust-retaining film were found to be the most critical factors affecting the efficiency of fly-dust prevention. From recently published screen data and specific surface-area measure-ments on United Kingdom coals, an approximation of the surface exposed by mine-run coal and by 1-in. slack was made. The total surface area exposed by an average ton of this mine-run coal was estimated at 3768 sq. yd., while a ton of 1-in. slack represents a total surface area of 8779 sq. yd. with no additions for porosity. It is important in coal treating to consider that in mine-run coal the fraction above 1/4 in. in size represents 79.5 per cent of the total weight, but only 4 per cent of the total surface, while the fraction below 150 mesh contains 47 per cent of the total surface and only 1.2 per cent of the total weight. Also, one should appreciate that, in a 1-in. slack, the domestic stoker fraction (1 in. to 8 mesh) contains 76.3 per cent of the weight and 8.2 per cent of the surface, while the fraction below 150 mesh represents 3.3 per cent by weight and 54.8 per cent by sur-face area. Wax extraction data on 1-in. to 0 slack from mine-run treated Free-port-seam coal showed that the coating was distributed uniformly as a function of exposed surface; hence, nonuniformly on a weight basis. This distribution of the coating on mine-run coal therefore limits the extent of treating that is desirable on bituminous coal at this point in the preparation. The treatment of Freeport mine-run coal before it reached the tipple gave a 70 to 80 per cent reduction of fly-dust in the tipple, a satisfactory treated commercial slack coal, and an indicated change in the trend of tipple degradation. The premium-treated domestic sizes required a supplemental treatment for complete dustproofness.

Jan 1, 1937

By R. T. Hukki

John F. Myers (Consulting Engineer, Greenwich, Corm.)—Since the art of comminution has lain practically dormant for many years, it is very interesting that R. T. Hukki approaches the subject with a new concept. One is reminded of the research carried on by A. W. Fahrenwald of Moscow, Idaho, a few years ago. Fahrenwald mounted a steel bowl on a vertical shaft. The balls and ore placed in the bowl were rotated at fast speeds, thus simulating the supercritical speeds used by Hukki. The rolling action of the balls against the smooth shell liner has pretty much the same effect. The action is horizontal in one case and vertical in the other. Both researchers report good grinding activity. It is also constructive that such able investigators give to the students of comminution their interpretation of their laboratory results in terms of large-scale operation. History shows that it takes a lot of time for such radically new ideas to be absorbed by the industry. Typical of this is the present-day activity of cyclone classification in primary grinding circuits. The idea of cyclone classification has been kicking around for 30 or 40 years. Certainly we all suspect that the ponderous grinding mills of today, and their accessory apparatus, large buildings, etc., will ultimately give way to small fast units, just as this has occurred in other industries over the past 50 years. At the moment there is no evidence that ball and liner wear is prohibitively high. In fact, at the time Fahrenwald was demonstrating his high-speed horizontal machine at the meeting of the American Mining Congress, several years ago, he assured this writer that the balls retained their shape much longer than they do in conventional tumbling mills. Rods and balls that slide (as some operators in uranium plants are experiencing) get flat. Apparently the balls have a rolling action. Mr. Hukki's references to the processing capacity of the Tennessee Copper Co. mills is adequate. Those studying this subject will be greatly interested in the paper presented by Richard Smith of the Cleveland-Cliffs Iron Co. at the annual meeting of the Canadian Institute of Mining and Metallurgy in Vancouver April 24, 1958. This paper will be published during the latter part of 1958 in the Canadian Institute of Mining and Metallurgy Bulletin. Hukki's pioneering spirit is to be commended. R. T. Hukki (author's reply)—It has been heartening to read the objective discussion by J. F. Myers. The sincerity of his opinions is further strengthened by the fact that the article he has discussed contradicts in a major way the parallel achievements of his life work. Myers is right in his opinion that in general it takes a long time before new ideas are accepted by the industry. On the other hand, revolutions usually take place at supercritical speeds. There are many indications at present that both the unit operation of grinding and the related subject of size control are now just about ripe for a revolution. In grinding, brute force must ultimately give way to science. Rapid progress can be anticipated in the following fields: 1) Autogenous fine grinding at supercritical speeds will be the first advance and the one that will gain recognition most easily on industrial scale. At this moment, little Finland appears to be leading the world. Crocker recently made a statement that in nine cases out of ten, your own ore can be used as grinding medium more effectively and far more economically than steel balls. This is true. The present author would like to introduce a supplementary idea: In eight cases out of the nine cited above, it can be done at the highest overall efficiency in the supercritical speed range. Fine grinding must be based on attrition, not impact. The path of attrition may be vertical, horizontal, even inclined. 2) In coarse grinding, the conventional use of rods is sound practice. However, even the rods can be replaced by autogenous chunks large enough to offer the same impact momentum as the rods. To obtain the momentum, the chunks must be provided with a free fall through a sufficient height in horizontal mills operated at supercritical speeds. Coarse grinding must be based on impact. Detailed analysis of the subject may be found in a paper entitled "All-autogenous Grinding at Supercritical Speeds" in Mine and Quarry Engineering, July 1958. 3) All conventional methods of classification, including wet and dry cyclones, are inefficient in sharpness of separation. Continuous return of huge tonnages of finished material to the grinding unit with the circulating load is senseless practice. In the near future the present methods will be either replaced or supplemented by precision sizing. These three fields are also the ones to which J. F. Myers has so admirably contributed in the past. Fine Grinding at Supercritical Speeds. By R. T. Hukki (Mining EnGineERInG, May 1958). Eq. 9, page 588, should be as follows: T , c, (a — 6') n D Ltph On page 584 of the article the captions for Figs. 4 and 5 have been placed under the wrong illustrations and should be interchanged.

Jan 1, 1959

By James Norman

SPODUMENE is a lithium-bearing pyroxene, and is an important source of lithium compounds. Because of its high alumina and lithia content it might be a desirable constituent of glass batches. The use of spodu-mene in ceramics will undoubtedly increase, as it has been shown that a mixture of the proper proportions of this mineral with soda feldspar and potash feldspar has a much lower maturing temperature upon firing than has any one of the three components.1 The mineral spodumene seldom occurs as pure mineral, but ordinarily with feldspars, mica and quartz. All spodumene-bearing rocks tested contained these minerals as gangue. Small amounts of iron and manga-nese oxides also were present, usually as stains on the silicate grains. Mica associated with the spodumene carried a considerable amount of lithia. This was discovered in flotation tailings, which, although virtually free of spodumene grains when examined microscopically, showed 0.4 to 0.5 per cent Li20 on chemical analysis. The lithia content of micas picked from the North Carolina spodumene rock was variable. Some samples contained little lithia, others more than 3 per cent. In 1938, under the supervision of Oliver C. Ralston, ? the Bureau of Mines, in cooperation with the Tennessee Mineral Products Corporation, undertook to study the beneficiation of North Carolina spodumene by froth flotation. The Bureau had previously published investigations on the beneficiation of spodumene.2,3 The methods described in the second publication' did not give good results with badly weathered spodumene rock, so that more thorough investigation of the subject was warranted.

Jan 1, 1940

By Heinrich Ries

In another place,* the writer has called attention to the modern methods of the laboratory investigation of clay, and it is desired here simply to discuss one branch of the subject, which, though of considerable importance, has heretofore received little attention in this country, viz., the rational analysis of clay. In order, however, the better to point out the bearings and advantages of this procedure, it is necessary to refer briefly to the ultimate analysis as well. The remarks in this paper refer only to the use of clay for the manufacture of clay-products. Pure clay or kaolin-f is extremely refractory, possesses little plasticity, and usually shrinks aud warps considerably in burning. Even the smallest proportion of impurities changes these properties, so that the kaolin exhibits variations in shrinkage, plasticity, tensile strength, fusibility, and often color when burned. The majority of nearly pure kaolins consist of kaolinite (A1,O2 2SiO,, 2H20), undecomposed feldspar, and quartz. The kaolinite generally forms the finest particles of the clay and is known as the clay-substance, while the rest of the clay-particles are collectively spoken of as sand. In the ordinary or ultimate analysis, the substances generally determined are silica, alumina, ferric oxide, lime, magnesia, alkalies and water. An analysis of this type simply regards the clay as a mixture of elements or oxides, but gives no clue as to the actual condition in which these substances exist, i.e., whether as silicates, oxides or carbonates, etc., a point which it is of the highest importance to know; for the individual components of the clay influence its properties not only according

Jan 1, 1899

By A. L. Marshall, F. J Norton

The object of this investigation was to make a comprehensive study of the degassing of molybdenum in order to determine how rigorous a treatment was necessary to completely remove sorbed gases from molybdenum electrodes in vacuum tubes. Some work has also been done with tungsten, nickel, iron and carbon. As a logical development of this work it has been shown that the gas is present throughout the body of the metal and a study has been made of the solubility of nitrogen in molybdenum and tungsten and the rate, of diffusion of nitrogen through molybdenum has been calculated. Tests were made on molybdenum from all the commercial sources and no difference was discovered in the nature of the gases present, the amounts or the ease of removal. The reason for this was apparent when a study was made of the manner in which gases are absorbed by gas-free molybdenum. It is necessary to heat molybdenum to 1760°C. in a vacuum of the order of 0.001 micron for a time which varies lineally with the thickness, in order to obtain a condition in which no further gas is evolved by the sample. A sample so degassed can be handled and subsequently assembled in a tube and then degassed readily. The gases obtained from molybdenum are carbon monoxide and nitrogen, the nitrogen being the more difficult to remove. Apparatus and Technique The apparatus is shown in Figs. I and 2. It consisted of two units, a degassing system and an analytical system. Each had a bake-out oven, as shown surrounding the systems in the sketches. The system , will be traced, starting from the sample in the degassing system. A water-cooled quartz chamber surrounded the sample. The high-frequency coil, which heated the sample, extended only around this chamber and was cooled by an air blast. High-frequency power of 1800-meter wave length was obtained from a self-rectifying oscillator circuit with a maximum power input of 20 kw. A graded seal connected the quartz to the rest of the apparatus, which was of hard glass. The temperature of the molybdenum sample was observed by an optical pyrometer through an optical window about 40 cm. distant from the sample. Since the object viewed under these conditions was not a black body, true temperature was not observed, but the so-called "brightness temperature." The correction of this to true temperature is discussed in a later section. The apparatus was taken apart just above the graded seal; the quartz chamber was slipped off, washed with nitric acid, water and alcohol, and dried by an air stream. The old sample was removed by unscrewing the lower nut, and the new

Jan 1, 1944

By A. L. Marshall, F. J. Norton

The object of this investigation was to make a comprehensive study of the degassing of molybdenum in order to determine how rigorous a treatment was necessary to completely remove sorbed gases from molybdenum electrodes in vacuum tubes. Some work has also been done with tungsten, nickel, iron and carbon. As a logical development of this work it has been shown that the gas is present throughout the body of the metal and a study has been made of the solubility of nitrogen in molybdenum and tungsten and the rate, of diffusion of nitrogen through molybdenum has been calculated. Tests were made on molybdenum from all the commercial sources and no difference was discovered in the nature of the gases present, the amounts or the ease of removal. The reason for this was apparent when a study was made of the manner in which gases are absorbed by gas-free molybdenum. It is necessary to heat molybdenum to 1760°C. in a vacuum of the order of 0.001 micron for a time which varies lineally with the thickness, in order to obtain a condition in which no further gas is evolved by the sample. A sample so degassed can be handled and subsequently assembled in a tube and then degassed readily. The gases obtained from molybdenum are carbon monoxide and nitrogen, the nitrogen being the more difficult to remove. Apparatus and Technique The apparatus is shown in Figs. I and 2. It consisted of two units, a degassing system and an analytical system. Each had a bake-out oven, as shown surrounding the systems in the sketches. The system , will be traced, starting from the sample in the degassing system. A water-cooled quartz chamber surrounded the sample. The high-frequency coil, which heated the sample, extended only around this chamber and was cooled by an air blast. High-frequency power of 1800-meter wave length was obtained from a self-rectifying oscillator circuit with a maximum power input of 20 kw. A graded seal connected the quartz to the rest of the apparatus, which was of hard glass. The temperature of the molybdenum sample was observed by an optical pyrometer through an optical window about 40 cm. distant from the sample. Since the object viewed under these conditions was not a black body, true temperature was not observed, but the so-called "brightness temperature." The correction of this to true temperature is discussed in a later section. The apparatus was taken apart just above the graded seal; the quartz chamber was slipped off, washed with nitric acid, water and alcohol, and dried by an air stream. The old sample was removed by unscrewing the lower nut, and the new

Jan 1, 1944

By John H. Bassarear

By 1968, Cyprus Pima was milling 34.5 kt /d (38,000 tpd) of copper ore using a conventional flowsheet consisting of three stages of crushing, rod milk and ball, mills. A 13.6 kt /d (15,000 tpd) expansion was put onstream late in 1971 using primary crushing, semiautogenous milk, and ball mills. Identical ore is treated in both concentrators. This paper shows the weight and life of each liner for each crusher and each mill over a four year period from 1974-1977. Media consumption is shown for the same period and a comparison is made between the two reduction methods.

Jan 1, 1983

By O. W. Ellis

In view of the extensive use of the brasses and bronzes in engineering practice it is indeed surprising that so little scientific work has been done on the oxides in these alloys. Recognition of the ill effects of these compounds is universally accorded, both in foundry procedure and in such specifications as cover the melting of these useful mixtures. In the latter, limits, for example, are placed on the proportions of scrap metal In the charge, and clauses governing the use of fluxes are included, the addition of fluxes to the charge being made with the object of avoiding oxidation during the process of melting and of subducing and separating non-metal-lic matter from the melt.1 In the manufacture of brass it occasionally, though rarely, occurs that the virgin metals, copper and zinc, alone arc used. In the event of virgin metals being employed, that of the higher melting point is always melted first. If it is melted under suitable conditions, little or no oxidation will occur. Whether oxidation has occurred or not, however, can best be determined by microscopic examination of a sample taken from the melt. Avoidance of Oxidation in Furnace Practice When melting virgin copper in crucible practice, the avoidance of oxidation is not difficult, nor is it hard to forestall trouble in the electric furnace. In gas-fired furnaces of the barrel type, however, the avoidance of oxidation is almost impossible, no matter what the condition of the flame, the flux employed, or the amount of charcoal included in the charge. Copper melted in furnaces of this type is almost invariably so highly oxidized as to requirc very considerable additions of such deoxi-dizers as, for example, silicon copper to render it free from cuprous oxide. As a result,, the castings produced are decidedly inferior, on account of the. large amount of silica which is engendered in the metal as a result of the reaction, Cu2O + Si = SiO2 + 2Cu. The deoxidation of such oxidized copper could, of course, be effected by means of zinc with, however, even more disastrous results.

Jan 1, 1930

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Jan 1, 1925

By Carl Henrich

In the planning and erection of smelting-works, especially of such as contain the modern large water-jacketed blast-furnaces, we are often confronted with an insufficiency in the watersupply. It may be impossible to find in the immediate neighborhood of the selected site a sufficient supply to furnish the jackets with cold water. Or there may be enough water for this purpose, but it may be highly charged with scale-forming minerals held in solution. Or, the main water-supply, if pumped from the workings of a mine, may carry iron- or copper-salts, or even some free acid in solution, all of these substances being derivable from the oxidation of sulphuret-ores in the mine. Moreover, such mine-waters sometimes contaminate the waters of the creeks, so that these become unavailable, and we have to fall back on an inadequate supply of pure water furnished by some spring or springs, entirely too small in

Jan 1, 1896

By Frederick Laist

The ores received at the Washoe Smelter come almost entirely from the mines in Butte and contain the following minerals : Chalcocite, Cu2S; covellite, CuS; chalcopyrite, CuFeS2, (trace); bornite, Cu3FeS3; enargite, Cu3AsS4; malachite, Cu2CO4 + H2O (trace); pyrite, FeS2; sphalerite, ZnS; rhodo-chrosite, MnCO3, (less than 1 per cent.); rhodonite, MnSiO3, (less than I per cent.). The country-rock of Butte is of the granite family and is a quartz-monzonite containing a little less silica than typical granite. It is made up of the following rock-minerals in approximately the proportions indicated: Minerals. Composition. Per Cent. Quartz SiO2 20 Andesine 1/2 NaAlSi3O8; 4 CaAI2Si2O8 42 Orthoclase KA1Si308 23 Hornblende 1/2 Ca(MgFe)3Si4O12; & (MgFe)2(AlFe)4Si2O12 6 Biotite (HK)2(MgFe)2A12Si3O12 9 Titanite CaTiSiO5 0.1 Apatite (CaF)Ca4(PO4)3 0.05 Magnetite (FeO)(Fe2O3 0.15 Pyrite FeS2 0.02 99.32 The main country-rock (quartz-monzonite) is cut by dikes of aplite, a granite having the following composition: Quartz, 30; andesine, 20; orthoclase, 45; ferro-rnagnesian minerals, 3; pyrite, 0.1; total, 98.1 per cent. Closely associated with the copper-deposits are dikes and bodies of " Modoe" porphyry, technically known as quartz-

Jan 1, 1913

By C. E. Beecher

THE application of gas or air under pressure to obtain more oil from a sand which has been practically exhausted by ordinary production methods has been practiced to a limited extent for many years. Until recently such methods were confined to the Eastern fields, principally those of Ohio and West Virginia, where in many cases the production obtained after applying pressure for a few years was nearly equal to the total production prior to that time which had been obtained by the usual production methods.' As early as 1917, J. 0. Lewis1 called attention to this method of increasing the recovery of oil and cited the phenomenal results obtained by H. E. Smith, I. L. Dunn and 0. C. Dunn, who pioneered the application of air or gas pressure recovery methods. With this information available it would appear that other oil-producing sections of the country have been extremely slow to realize the advantages of repressuring. However, after a few successful projects in the Mid-Continent area, the oil producers appreciated the value of this method for obtaining further and profitable production from their practically exhausted leases and are now making extensive use of it. In general, it has been the practice to apply pressure to the sands when production has declined to a small yield per well. The purpose of this paper is to discuss some of the advantages which may be expected from returning gas under pressure to the oil sands during the early stages of development, before the rock pressure has been dissipated and the gas exhausted, and to stimulate discussion of this subject on which comparatively little actual field data are available.

Jan 1, 1928

By John D. Morgan

Uncertain world conditions of the present time require that this country be prepared to meet: 1) all out nuclear war with attack on the U. S.; 2) limited wars; 3) political, economic, and/or pyschological warfare. Our present position as a major world power derives in large measure from our free institutions and great industrial productivity, and this productivity in turn depends on a continuing flow of raw materials-metals, minerals, fuels, and agricultural products. The U. S., with only about 6 pct of the world's population, uses from one to two thirds of the world's annual supplies of most metals and minerals. The U. S. strategic materials stockpiling program is designed to enhance our national security position: as stated in the preamble of the Stock Piling Act, to decrease and prevent wherever possible a dangerous and costly dependence upon foreign nations for supplies of strategic and critical materials in times of national emergency.

Jan 8, 1960