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By R. T. Webber, B. B. Owen

THE vapor phase deposition of molybdenum and tungsten from the hexacarbonyls has been thoroughly investigated by Lander and Germer1 and shown to yield well-bonded coatings on a variety of hot metallic surfaces. They also demonstrated that chromium coatings2.3 could be similarly deposited, but did not investigate this metal extensively. Recently,4 conditions have been described by which this compound can be prepared in quantities sufficient for laboratory scale plating experiments, and it is the purpose of the present communication to outline the results of preliminary experiments upon the plating of chromium from its carbonyl. APPARATUS AND TECHNIQUE The apparatus used in these experiments is shown in Fig I. At one end, connected by a short length of rubber tubing, is a Cenco Hypervac 20 pumping continuously. At the opposite end is a needle valve which allows a small stream of purified hydrogen to flow through the apparatus. Connected in series are a trap T1, maintained at the temperature of dry ice and acetone, the plating chamber, and two traps T2 and T3 containing crystals of the carbonyl. T2 is kept in a constant temperature bath (not shown), while T3 is at room temperature. Stopcock S6 allows the hydrogen flow to by-pass the carbonyl traps. A McLeod gauge is connected so that it can measure the pressure at the pump through Ss, or the pressure at the plating chamber through S9 and S6. The standard (12 liter) volume connected by S5 is used to determine the volume included by S4, S6, Se, S10, the needle valve and the McLeod gauge. Knowledge of this volume allows calibration of the flow of hydrogen. The apparatus* is built entirely of pyrex, except for the needle valve, the rubber connection to the Hypervac, and the cover of the plating chamber. The plating chamber is water-jacketed, with a large brass top allowing insertion of the specimen to be plated. Set into the brass top is a ground glass stopper through which thermocouple leads are sealed. The thermocouple wires (pure Pt, and 87 pct Pt-13 pct Rh) serve the double purpose of measuring the specimen temperature and suspending it in the chamber. Surrounding the chamber is the coil of an induction heater, H. The apparatus is designed to allow variation of the following conditions: I, the specimen temperature, from room temperature to about 1000°C, 2, the carbonyl vapor pressure, from 40 to 220 microns, and 3, the hydrogen flow. In several runs, 0.8 to 1.8 pct of hydrogen sulfide was introduced through a needle valve that replaced S4. The vapor pressure of the carbonyl is

Jan 1, 1948

By R. B. Ellestad

Introduction Lithium has been known since 1817, when it was discovered by the Swedish chemist, Arfvedson, while working in the laboratory of Berzelius on the chemical analysis of the mineral petalite, LiAl(Si205)2. Development of the chemistry of lithium proceeded slowly, following the early work of Davy, Gmelin, Bunsen, and Matthiessen. Approximately seventy years elapsed before lithium products assumed any commercial importance, and for a considerable period it was a' very minor industry. Their chief early use seems to have been in medicine, and in the production of lithiated water. Other more important uses were gradually discovered, and the industry has had a slow but steady growth. Chemistry Lithium is classified as an alkali metal, along with sodium, potassium, rubidium, and cæsium. Like these, it is a silvery-white metal, which can be cut with a knife; it is harder than sodium, but softer than lead" It is remarkable in having a density of only 0.53 gram per cubic centimeter, which makes it the lightest metal. On ignition in air, it burns intensely to form chiefly lithium monoxide, Li2O. Like the other alkali metals, lithium reacts vigorously with water to form hydrogen and lithium hydroxide. The later is a strong base, and reacts with acids to form salts. The salts of lithium are in general analogous to those of the -other alkalies, but many of them have unique properties. For example, lithium chloride and bromide are extremely hygroscopic, and have a very high water solubility. Lithium fluoride, phosphate, and carbonate, on the other hand, are all relatively insoluble, unlike the corresponding sodium and potassium compounds. In this instance, lithium exhibits its frequent tendency to resemble the alkaline-earth group of elements (calcium, strontium, and barium). Many of the special and valuable properties of lithium are related to the extremely small size of the lithium ion.

Jan 1, 1948

By M. H. Kline

Round Mountain is one of a number of locations investigated by the Bureau of Mines in its search for manganese deposits during the early phases at the strategic minerals program. The Suiter mine, on Round Mountain, had provided some 5,000 tons of manganese concentrates during the period 1917 to 1919, and early in 1941 prospecting by the Virginia Hardwood Lumber Co. in this same area had discovered manganese on what later became known as the Hall Pit. These promising indications encouraged the Bureau to begin an exploration project in search of additional reserves of manganese on Round Mountain in January 1942 (fig. 1).

Jan 1, 1948

By E. D. Gardner

The American petroleum industry is supplying the present domestic demand for liquid fuels. Known reserves of petroleum in the ground, however, are limited, and the .cost per barrel of finding new oil pools is increasing. Any deficiencies of domestic production in the near future doubtlessly could be made up by imports: Dependence upon foreign oil for part of our industrial requirements is not necessarily cause for alarm, but in time of war an adequate, dependable, domestic source of liquid fuels is vital to the defense of the country. As a national defense measure, and to insure a future continuous oil supply for our economic machine, it would appear logical to take steps now to develop methods for producing petroleum substitutes within our own borders. This undoubtedly was in the mind of Congress when it passed the Synthetic Liquid Fuels Act (58 stat.190; 30 U. S. C. Sup. Secs. 321-325), Approved April 5, 1944.The title' of the Law reads: An Act authorizing the construction and operation of demonstration plants to produce synthetic liquid fuels from coal, oil shales, agricultural and forestry products, and other substances, in order to aid the prosecution of the war, to conserve and increase the oil resources of the Nation, and for other purposes. Congress authorized $30,000,000 for a 5-year program and directed the Bureau of Mines to carry it out. The part of the program pertaining to oil shale is being conducted on Naval Oil-Shale Reserves Nos. 1 and 3 (fig. 1) at Anvil Points, near Rifle, Colo.

Jan 1, 1948

Jan 1, 1948

PRESIDENT OLIVER: May I have your attention, please, gentlemen? The Forty-Fourth Meeting of the Rocky Mountain, Coal Mining Institute is now In session. I want to say just a few words of welcome to all the delegates this morning, both old and new. There is a large group of men around here I notice who come to this meeting year after year, and it occurs to me that they must be getting something worthwhile out of these meetings, the renewal of old acquaintances, the making of new acquaintances, and the opportunity to find out what is doing in the technical end of the coal business, and what is new. So, we greet you enthusiastically and trust that you will find this meetnig on a par with all those which have gone before and. that each one of you will leave these sessions determined that you will not miss next year but will be back again. So, with that introduction, we will proceed with the business of the convention. As time is fleeing away from us, if there is no objection, I wil lentertain a motion to dispense with the reading of last year's minutes. Will somebody make that motion? MR. H: C. MARCHANT: I move we dispense with the reading of last year's minutes. (The motion was carries unanimously.)

Jan 1, 1948

By Max Littlefield, Godbold A. C., Gray L. L.

The West Edmond pool of Central Oklahoma, a limestone reservoir, has an area in excess of 29,000 acres and as of Sept. 15, 1946, had produced 53 million barrels of oil from 731 wells at an average depth of 6900 ft. Water has encroached into the reservoir along the west side of the pool and although the area of water invasion is large the net volume of water influx is small, because encroachment has been primarily into a fracture system. The most significant part of this study concerns the character of the Hunton reservoir. Geological study of cores of the producing section was made to supplement core-analysis data. It was determined that approximately 90 pct of the pore volume was contained in intergranular or sand-like porosity and 10 pct in fractures (intermediate porosity). The porous limestone is divided into blocks by the fractures, although in the strongly dolomitic parts of the producing section, fractures are less well developed. The low-permeability intergranular porosity, largely subsidiary to the high-permeability fractures, will produce oil into the fractures by evolution of solution gas. The fractures in effect serve as drainage channels for production of oil from the inter-granular porosity. Because of such a large difference in permeabilities of the two com-ponents, a high degree of by-passing will occur, and, accordingly, the economics involved in undertaking full-scale high pressure gas injection operations have been seriously questioned. Introduction The West Edmond Hunton pool, which covers portions of Canadian, Logan, Oklahoma, and Kingfisher Counties in Central Oklahoma, is the largest reservoir producing oil from a limestone in the state. The total area of the pool comprises about 29,240 acres and development is considered to be essentially complete. In all, 731 producing wells have been completed in the Hunton reservoir at an average depth of approximately 6900 ft, and have yielded a cumulative oil production in excess of 53 million barrels as of Sept. 15, 1946. In addition to wells completed in the Hunton limestone, 21 wells have been completed in the Bartlesville sand at a depth of approximately 6500 ft, which have produced a total of 730,000 bbl of oil. One small producer has been completed in the Cleveland sand at a depth of 5700 ft. However, a study of only the Hunton limestone reservoir will be presented in this paper. The most significant phase of this study concerns the special type of geological core examination that was made in an effort to ascertain the type and degree of porosity in the rock in accordance with lithologic types. Results of this geological study showed the west Edmond pool to be of such a complex nature as to appreciably affect the behavior normally associated with homogeneous reservoirs. Recognition of this condition in the

Jan 1, 1948

By T. J. Ballard

The Union Copper mine is in the Gold Hill district; Rowan and Cabarrus Counties, N. C. The mine was discovered in 1799 and first worked as a gold mine; but copper was encountered at depth, and the property became an important producer of copper. It is estimated that the mine produced 5,000,000 pounds of copper before operations were discontinued in 1907. As part of the strategic minerals program, the Bureau of Mines conducted a development project on the property from July 1943 to November 1943. Eight diamond-drill holes totaling 2,500 linear feet were drilled to delineate the ore body. Analyses 205 core samples were made. Tabulations of sample analyses and drill-hole logs are presented in this report.

Jan 1, 1948

By G. Sachs, E. J. Ripling, S. I. Liu, J. J. Lynch

INTRODUCTION IT is a generally recognized fact that by repeated straining the fracture stress of any metal is reduced to a fraction of its value for static loading. The value of this fatigue strength depends upon numerous factors, such as the states of strain and stress, the limits of straining, and the number of repeated loadings or cycles.1.2,3 The large volume of previous investigations on fatigue is concerned entirely with large numbers of cycles, say exceeding 10,000 and up to 500,000,000. However, the changes in fracture stress and fracture strain occurring after a small number of repeated loadings have attracted little attention. Apparently the only investigations of this type are those byLudwik4,5 who subjected steel, copper, and aluminum wire to repeated torsion. In each test the torque was varied between identical values in the two directions of twisting. Depending upon the magnitude of the moment, fracturing occurred after a number of cycles, up to 10,000. The results of Ludwik's tests will be discussed later. Such torsion does not readily yield actual stress and strain values. Therefore a preliminary study was made of the effects of repeated direct stresses, i.e., tension and compression stresses. Because such tests are considerably more tedious than torsion tests, only high stresses were used in the preliminary work, yielding definite changes in metal properties after a few cycles. It was found in these tests that strains could be controlled more readily than stresses in the investigated range of high stresses. This paper, consequently, deals with the effects of strains of equal magnitude but different signs. The metal was first prestrained in static tension by a certain amount then subjected to compression to yield the same amount of strain after unloading. This loading cycle was repeated up to a maximum of seven times. After various cycles, the stress-strain curves in tension were determined, up to fracturing. As material for these tests, the aluminum alloy 24ST was selected because it exhibits a comparatively small amount of necking in the tension test. This alloy permitted, therefore, rather accurate control at the high strains necessary to produce fatigue failures at less than seven cycles. The results of this investigation appear sufficiently interesting to extend the method of attack in various directions. It is intended to study (I) the effects of cycles up to a few thousands and (2) the effects of strains of different magnitude in tension and compression, respectively. The latter variable also includes as a special case the effects of compressive strains.

Jan 1, 1948

For several decades miners have been obliged to maintain a vast supply of sharp steels at the working face to meet the hungry needs of rock-drills. In medium and large size mines this has meant the setting up of an organisation to store steels, to make and sharpen bits with all the complication and skill of forging, hot milling and heat treatment, and to transport sharp and dulled steels to and from the working face with all its labour, wastage, and inconvenience to other mining operations.In a mine with 250 rock-drills in use, a flow of more than 60,000 sharpened steels each month has to be maintained to keep the machines fully employed, so some idea of the magnitude of this problem may be grasped.For a long time it has been apparent that it is mainly the bit itself that wears, and many attempts have been made to reduce the enormity of the problem by providing detachable steel bits which could either be used once and rejected, or sharpened three or four times before rejection.At the same time metallurgists have striven to 'improve the quality of the steel and the heat treatment afforded it so that a bit, readily workable In a normal mine drill-shop, could be produced having a high resistance to wear and fatigue; but, although various alloy steels have been marketed, it is still usual to find many mines relying on a "straight" carbon (0.6 - 0.9% C.) steel for their drill steels.Since 1915 increasing use has been made of tungstencarbide as a cutting implement in the engineering industry. Where, on account of its great hardness and long life, it...

Jan 1, 1948

By J. L. Gillson

In a brief summary of the many occurrences of fluorspar in our western states, it is not possible to go into detail in regard to the geology, mining and milling methods, and reserves about individual deposits. Rather a broad review is made of the occurrences and an analysis of how the western deposits may fit into our future domestic economy is presented. General Statement on Fluorspar Situation Fluorspar has been used for years as a flux in the manufacture of basic open-hearth steel, in foundry cupolas for melting pig iron, in the manufacture of opalescent glass and in the preparation of hydrofluoric acid. In 1880 the annual production of fluorspar in the United States was around 4000 tons per year. By 1900 it was up to 21,656 tons and between 1902 and 1908 it averaged about 40,000 tons annually. Prices were then so low, by present standards, that it seems impossible to believe now that mining could have been performed profitably at the price levels then prevailing. In 1890 fluorspar sold at the mines for $6.70 per ton, in 1901 for $5.81, in 1916 for 85.92. When the United States entered World War I, flyorspar production and price skyrocketed; the production reached 263,817 tons in 1918, with prices above $20.00 per ton, and prices were even higher in 1919 and 1920. After 1920, the domestic production fell from the 1918 level to about 125,000 tons annually and the average price dropped back to about $18.00 per ton. By 1935 the average price had fallen to $15.00, but in 1940 with a rising demand the average price of all grades had gone back up to $20.31. Today it is 75 per cent higher than in 1940 and presumably the price of acid grade at .least would be even higher if it were not for price ceilings. The first subsequent year that the domestic production exceeded that of 1918 was 1941, and the 1944 production is expected to exceed 400,000 tons, or over one and a half times that of 1918. In five-year periods, average production and imports were as are shown in Table I. Many people concerned with the consumption of fluorspar believe that the postwar period ahead will show a repetition of price trends of the last such period. They believe that imports will be again an important factor in the available supply and the price will fall back gradually toward the prewar level. The following basic factors are pertinent in analyzing this conclusion:

Jan 1, 1948

By Stanton L. Tainter

As a part of a wartime program to aid in the development of known ore bodies and in the discovery of hitherto unknown deposits of strategic minerals, the Bureau of Mines investigated the feasibility of diamond-drilling the Christmas copper deposit, in Gila County, Ariz., to increase the reserves of milling ore. Upon recommendation of the examining engineer, drilling was begun in September 1942, from the bottom (770) level of the mine. One month later, in cooperation with the Bureau, the Federal Geological Survey started geologic mapping of the mine workings. Since extensive and costly development would be required, the War Production Board concluded that ore below the bottom level could not be mined at that time because of the wartime shortages of equipment and man-power. In January 1943, drilling was moved to the 300 and 400 levels to locate reserves readily accessible for continued production of fluxing ore. This drilling, which was under the supervision of L. G. Marshall, was completed in January 1944.

Jan 1, 1948

By W. J. Long

The gradual depletion of high-grade mineral deposits and the necessity for development of lower-grade deposits together with the increased demand for nonmetallic minerals has increased the importance of the ore-dressing field during recent years. There is strong need for development of new ore-concentration methods and-machines to keep pace with the constant changing of marketing specifications and requirements resulting owing to the many new uses made of mineral products by the metallurgical industry.

Jan 1, 1948

By Thomas A. Jones

An impure variety of barite, which lends itself well to the manufacture of heavy drilling mud for oil wells, is widely distributed throughout the Ouachita Mountains in Arkansas. The ore mined in the area and used for drilling muds usually contains an average of 67 percent barium sulfate, although ores as low as 50 percent BaSO4 are occasionally used. Due to the increased demand for barite for drilling caused by the intense search for hew oil occurrences during the years 1945 and 1946, the Federal Bureau of Mines began an investigation of barite deposits in the Ouachita? Mountains in October 1946. In all, 10 barite deposits were examined, trenched, sampled, and studied during the investigation, which was terminated in May 1947.

Jan 1, 1948

By Walter V. Knopp, Laurence Delisle

INTRODUCTION THE aim of this work was the preparation of nickel-steels from elemental metal powders by powder metallurgy techniques. It was known that plain carbon steels could be made from a mixture of iron powder and graphite and that the effect of carbon on iron in powder form was of the same nature as that produced in fusion metallurgy. The problem in making nickel steels from elemental powders consisted therefore in finding out whether sufficient diffusion of the nickel and other incidental metals normally present in such steels could be induced in the solid state to modify the properties of plain carbon steels made from powders and produce the beneficial effect of alloying. The composition selected originally was that of an S.A.E. 2330 steel. Metal powders, in the proportion corresponding to that composition, were mixed with graphite, pressed, and heated at different temperatures for different periods of time, to produce bonding of the metal particles and mutual diffusion of the various elements without melting. Temperatures up to 1325°C and sintering periods as long as 6 hr were first investigated because it was expected that such conditions would produce maximum diffusion with an accompanying improvement in the properties of the alloy. It was found that, although diffusion proceeded to a large extent under the conditions investigated, it would not be complete unless sintering were carried out at a high temperature for much longer than 6 hr. Relatively high temperatures and long sintering times are objectionable from a practical point of view, particularly when a low cost material is to be produced, because they necessitate the use of special, costly equipment. Work could be done to improve the diffusion of iron and nickel by changing conditions other than the sintering temperature and time, i.e., finer primary or alloy powders could be used. However, a marked change in the properties of the steel had been observed even with only partial diffusion. It was thought, therefore, that instead of trying to improve the diffusion, advantage might be taken of its incompleteness to produce a special structure consisting, in the unquenched condition, of a hard constituent, rich in nickel, dispersed in a tough pearlitic matrix. Steels with such a structure, not readily obtainable by fusion, should have desirable mechanical properties. Besides, it should be possible to prepare them from elemental powders under economical conditions. This latter alternative was therefore adopted for the second phase of this work. This report is divided into four parts: 1. General Procedure. 2. Effect of Sintering Temperature. 3. Effect of Varying the Nickel Content. 4. Effect of Alloying Elements. GENERAL PROCEDURE The general technique of cold pressing as used in powder metallurgy was applied.

Jan 1, 1948

By Michael J. Messel

The critical shortage of asbestos fiber in the world today brings to the foreground the question of locating and developing new deposits. The object of this paper is to discuss some of the more important factors which should be considered in the examination and valuation of a new asbestos enterprise. Some of the more important uses of asbestos fiber are for textiles, heat insulators, building materials, filters and a series of other uses. The properties of this mineral, such as fibrous structure, color, strength, silkiness and flexibility, coupled with resistance to fire, certain chemical action and decay make its application unique for certain industrial uses which consume over 500,000 tons annually. These same unique properties which make this mineral so valuable also make a deposit one of the most difficult to appraise accurately, because of the many undeterminable and varying factors which must be considered before a deposit can properly be termed commercial. The majority of the asbestos fiber today, having the above mentioned properties, is sold by grades which are based on fiber length. Present day fiber prices vary over a wide range from $800 to $225 for crude fibers and $300 to $20.00 per ton for milled grades. For valuation purposes a careful study should be made of existing fiber prices and markets. Examination of Deposits In carrying out prospecting and examination of a deposit, considerable caution is required to get the necessary information in the form that will have the most value for the final determination. There are two main classes of asbestos fibers, chrysotile and the amphiboles, the chrysotile being, by far, the most important both in abundance and uses. This paper will stress mainly chrysotile deposits, however, the amphiboles have many important uses, especially amosite and crocidalite. Their valuation presents special problems as other factors may be involved, especially as they are not graded according to any well defined and adopted standard but usually according to the use for which they are being supplied. Most chrysotile deposits occur in two main types of rock, (I) mainly in basic igneous, such as dunite and peridotite, (2) to a lesser extent in sedimentary rocks, such as dolomite and limestone. All of these require a certain degree of metamorphism to be favorable to asbestos formation. Approximately 90 pct of the asbestos deposits are derived from serpentinization of dunite or peridotite, whereby the magnesium-silicate olivine was altered to hydrous magnesium-silicate serpentine. Under certain favorable geological conditions, this serpentine takes a fibrous form having a definite crystal structure, probably due to molecular rearrangement, and is known as chrysotile. The fiber veins are usually ir-

Jan 1, 1948

By Walter Miller

Crude oil stocks were some 10,000,000 bbl higher on June I, 1947, than at any time during 1946 but the extremely heavy refinery runs the last half of 1947 cut crude inventories to approximately the 1946 closing level of 225,000,000 bbl. Many refiners were seriously short of crude oil during the year. This shortage was reflected in numerous advances in the posted price of crude, justified in part as an incentive for more production but more generally due to competitive bidding. Some purchasers of crude, endeavoring to keep their plants running, resorted to the payment, either directly or indirectly, of premiums above the posted price. Another common practice employed by some suppliers of crude oil was to demand refined products in exchange or trade for their raw material. The refined products picture has darkened in spite of record throughputs. Stocks of gasoline and light and heavy fuel oils were uncomfortably low at the beginning of the year and were in general still lower at the close. The rationing of some products, principally gasoline, to dealers and stations? initiated during the year, gained momentum as stocks continued to diminish. The emphasis placed by the manufacturers of oil-burning equipment on the convenience and economy of heating with oil, together with the tight situation in coal, has developed a tremendous demand for burning oils. Consumption of liquefied petroleum gas for domestic and household fuel had more than doubled in 1946 over 1943, and the demand seems to be limited only by the ability of the equipment builders to furnish necessary storage. transportation, and burning equipment. The supply situation is likely to become more acute in 1948. Demand for petroleum products is being pushed to new heights not only by the unprecedented domestic market but by a sudden and drastic upswing in estimates of military and governmental requirements. Additionally, oil exports are running far below the volume requested, amounting to less than forty percent in a recent quarter, and export licenses are reportedly being approved on the basis of urgent need *only. AX recent White House release sees little likelihood that estimated requirements of the sixteen nations participating in the proposed Marshall Plan can be met in full over its projected life—1948 to 1951. Present demand dictates maintenance of refinery operations at the highest possible level and the Bureau of Mines has forecast daily average crude runs in 1948 of 5,265,000 bbl. The Economics Advisory Committee of the Interstate Oil Compact Commission recently estimated the 1948 demand for petroleum products at nearly 6 pct above 1947. They further estimate daily average crude runs of 5,375,000 bbl in 1948, some 2 pct higher than forecast by the Bureau of Mines. Projected demand exceeds supply to the extent that Capitol Hill is reportedly investigating ways of enabling oil companies to act in concert without danger of antitrust prosecution, such as elimination of crosshauls, pooling of products, and lowering of octane.

Jan 1, 1948

By L. Frost

Physical Conditions Great Britain The physical conditions in the mines investigated in Great Britain are similar to those found in the mines of the Dominion Steel and Coal Corporation, with the important difference that many of the coal seams visited were interspersed by a large number of heavy faults, making the development of a continuous face operation difficult, and in many cases the life of a unit development was exceptionally short, adding to unit cost; but in spite of these difficulties, a great deal has been accomplished in the application of mechanical loading units in a number of the mines in the areas visited. The coal-bearing measures, as in Nova Scotia, consist of shales and sandstones, and in some sections mussel bands overlie the coal seams making roof conditions difficult'. In several mines, the main roof consisted of weak shale bind, being held by a coal roof of varying thickness. This shale bind had a tendency to flow when the coal roof was broken. The floor, in some cases where cutter loaders were operated successfully, consisted of weak, flaky shales with very little resistance and a tendency to disintegrate into powder when broken. The depth of cover under which these mines were operating varied from 250 feet to 2,340 feet, with an average of 1,700 feet. The coal seams varied in height from 3 feet to 8 feet 6 inches, and the gradients from level to 33 per cent. The seams vary in hardness, but all-with the exception of one seam, the 'Morrison Busty'- presented a cutting problem similar to that found in Nova Scotia. The structure and cleavage of the coal was well defined and uniform. Some of the seams visited were gassy, ?but the temperature of the workings generally was not in excess of 70°F.

Jan 1, 1948

By Malcolm Black

Introduction The circumstances under which the gold mining industry was forced to curtail operations a few years ago are well known to all. The effect of those circumstances is particularly noticeable when one enters some of the larger mills that were designed, in better times, to treat relatively large tonnages. On their grinding floors one will observe that a number of grinding units are lying idle, and the ravages of rust are everywhere in evidence. The same applies to other equipment throughout these mills. In 1941, we found it necessary to reduce tonnage considerably in the Wright-Hargreaves mill. With the assumption that a lower tonnage would be of long duration, we began to focus our attention on some of the idle equipment with a view to re-arrangement of the flow-sheet for greater economy of operation. In an article by the writer published in the Engineering and Mining Journal (March, April, and May issues, 1939) , it was pointed out that in designing this mill there was a very limited floor space available. The choice of thickening equipment was imposed solely by the necessity for space: conservation. Thickening by gravity would have required 5,000 square feet of floor space, whereas Genter thickeners required only 1,200 square feet. As a consequence, the Genters were chosen. The decision to add flotation to the circuit was made primarily to save space. On a cost-plus-tail basis, 80 to 100 hours agitation on all pulp would produce similar overall results, but would require much more space.

Jan 1, 1948

By R. I. Jaffee, J. G. Dunleavy, H. R. Ogden, Webster Hodge

INTRODUCTION EARLY in 1946, at the instigation of the U. S. Army Signal Corps, the authors made an extensive survey of the available literature covering high-strength, high-conductivity alloys. For the purposes of the Signal Corps, the minimum tensile strength to be considered was 150,000 psi, together with at least 50 pct IACS conductivity. No single alloy was found to be in production, or mentioned in the literature, which had this combination of properties. The constitution diagram for the iron-copper alloys is not well established in the respect to the two-liquid region. Fig I, taken from the 1939 Ed. of the ASM Metals Handbook, shows a two-liquid system existing above the liquidus temperature, but disconnected from it. Although Ruer and Fick1 and Ruer and Goerens2 definitely established the fact that two liquid layers could occur in the system, Ruer3 was not convinced that the line off immiscibility was closed in the center. Maddocks and Claussen4 found no liquid immiscibility at temperatures up to 1570°C in alloys containing almost no carbon. Although the diagram would indicate age hardening of the copper-iron alloys is possible, Hanson and Fords found that little hardening effect could be obtained. However, Gordon and Cohen6 reported that the response is better if the quenching is very efficient. Although iron has a potent effect on the conductivity of copper, Hanson and Ford5 have shown that, when hot-rolled copper iron alloys are aged at 1200°F, the electrical conductivity decreases sharply with iron contents up to 0.2 pct Fe, and then levels off at conductivities between 60 to 70 pct IACS with compositions to 2.1 pct Fe. They also found that aging did not increase the tensile strength, although increasing iron content gave a moderate improvement in strength. High-strength copper-iron alloys, usually containing about 60 pct iron, had been reported by Smith and Palmer.7 They found that an alloy containing 56.4 pct copper, 0.21 pct magnesium, balance iron, would give a maximum tensile strength of 170,000 psi and an electrical conductivity of slightly over 35 pct IACS. The alloy could also be processed to have 150,000 psi tensile strength, and about 41 pct IACS conductivity. Decreasing the iron content increased the electrical conductivity, but the long mushy range during freezing of the alloy containing 10 to 20 pct iron made the production of good castings difficult, In spite of the difficulty encountered by Smith and Palmer with alloys of around 20 pct iron, it was decided to make a rather complete investigation 0f this type of alloy. As a result 0f this investigation, a method of alloying and fabricating copper alloys containing 10 to 15 pct iron was developed

Jan 1, 1948