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By Clarence Wright

THE average lead and zinc content of the ores mined and milled in the Joplin district is low as compared with that of other lead and zinc deposits throughout the United States. Because of this fact and of the high grade of the concentrates, the ratio of concentration is unusually high. Most of the operating companies have aimed to produce as high a grade of concentrate as possible in order to obtain the highest price for their product. They have done this at the sacrifice of the percentage of zinc recovered. The average percentage of zinc recovery is from 60 to 70 per cent. For percentage of recoveries from actual mill tests, see tables. The concentration is commonly effected by crushing the ore to h-in. (12.7 mm.) size and subjecting it to a roughing and cleaning over two or more large Cooley jigs, of the Harz type, the finer sands being treated on the usual types of sand and slime tables. The treatment of slimes by flotation is being tested at several of the larger mills. COARSE CONCENTRATION When the ore. has been hoisted from the mine it is dumped onto a chute leading to a grizzly made of iron bars, usually heavy rails, spaced 4 to -5 in. (101 to 127 mm.) apart. The oversize is caught on the grizzly, the mineralized pieces are broken with sledge hammers so as to pass through, and the boulders that are practically barren are sorted out by hand and trammed to the waste-rock pile. The proportion of waste rock thus sorted out varies from a fraction of 1 per cent to 15 per cent., depending on the nature of the rock.

Jan 10, 1917

By H. C. Goodrich

THE earliest record of copper production from the state of Utah comes from "The Resources of Utah," by. Mr. Fabian, in 1872, wherein it is stated that the. Mammoth mine of East Tintic was located in 1870 and that the ores yielded a large percentage of copper, silver and gold. It is also stated that shipments had been made to Swansea, England, which assayed between $200 and $300 per ton. The Mammoth-Copperopolis mine was located in, 1870 and sold the year following to an English syndicate. Some copper was shipped to. England and in 1873 there was constructed a 15-stamp mill and two copper smelting furnaces; these were operated a few months and before the end of the year were closed down and the property sold for debt. . This property -vas reorganized in 1879 and is at the present day a producer, though its principal product now is lead and silver. While a certain amount of copper has always been coming from the various lead-silver camps of Utah, the real history of copper in Utah should start with the discovery of the mines in Bingham Canyon, located about 25 miles to the southwest from Salt Lake City.

Jan 1, 1925

By W. M. Courtis

. There seems to be a well-established belief that there is an indescribable something in the appearance of gold-quartz not to be learned from books, that enables those who are fortunate enough to have acquired the power to recognize this characteristic, to pronounce at once that a certain quartz will or will not pay. The stronger this claim is made, the more certain is the claimant to be one of the self-styled practical miners. After several years spent among the gold-mines of California with practical and professional gold-miners, I have come to the conclusion that very few care to risk an opinion on a piece of quartz until some of it has been "horned out." Nevertheless, there is what the miners call a " kindly " appearance, that is more often followed by good results than is a vitreous, water-wet-looking quartz. A dark, resinous quartz seems to be most in favor, but there are so many exceptions that even quartz as " white as a hound's tooth " produces gold in some mines.. The ribbon-quartz, a laminated variety, separated by thin talc or chlorite partings, has a well-known good name. The slides of rich quartz specimens show that this parallelism is a microscopical characteristic of the only macroscopical distinction that, as a rule, these quartzes show. This is shown by Nos. 12 and 13, photographs of the richest quartz, that averaged $65 per pound. It is noticeable, also, in Nos. 7 and 9, and others. Dr. Hensoldt, of Columbia College, who prepared, excellently, a large number of my slides, and whom I have to thank for descriptions and suggestions, says of Nos. 12 and 13: "This variety of quartz differs considerably, microscopically, from the others of your locality, and is, in more than one respect, remarkable. Like the

Jan 1, 1890

By Homer Griffield Turner

The nature and comparative features of anthracite and bituminous coals have been discussed by the writer in two previous papers.' Although this paper is offered as a further contribution to the subject, it seems desirable at the outset to repeat some of the descriptive matter of the early works in order to show the actual connection between various constituents of both coals and the new photomicrographs and other physical and chemical properties. Structure of Anthracite and Bituminous Coals A lump of bituminous coal (Fig. 1) is readily seen to be composed of layers differing from one another in texture, luster and thickness. There are, in general, three kinds of layers, although only two are usually seen. One is deep black, very compact, and has a bright luster; another is grayish black, has a duller luster and is less compact; the third is black, dull and porous in appearance, but because of its thinness is not often seen except on parting surfaces. This last material is charcoal. American students of coal morphology use the names anthraxylon, attritus, and fusain to designate these three constituents of laminated coal. Anthraxylon refers to the brightest bands, attritus to the duller layers, and fusain to the charcoal. Close examination of a lump of bituminous coal shows the brightest deep black layers to be embedded in the duller grayish black laminae. These deep black layers are lens-shaped and vary in thickness from thin sheets to over half an inch. They are often so continuous through the lump that their tapering terminae are not noticeable. On careful examination the duller grayish black laminae (Fig. 7) are seen to contain many very thin sheets of this very bright black material. The charcoal

Jan 1, 1930

By D. A. Martin, Laird Crocker, W. I. Nissen

The Federal Bureau of Mines has developed a process for removing SO2 from stack gases. The process comprises absorption of SO2 in an. aqueous solution of sodium citrate, citric acid, and sodium thiosulfate, followed by reaction of the absorbed SO2 with H2S to precipitate sulfur and regenerate the citrate solution for recycle. A pilot plant was operated at The Bunker Hill Co. lead smelter in Kellogg, Idaho, to assess the feasibility of using the process for flue gas desulfurization. Nominal capacity of the pilot plant, which treated .tail gas from the lead smelter sintering furnace, was 1699 standard meters cubed per hour (15 degrees celsius) of 0.3- to 0.7-percent-SO2 gas yielding about 272 net kilograms of sulfur per day. The pilot plant was operated for about 4500 hours and produced more than 45 net tonnes of sulfur. The operation demonstrated that (1) more than 95 percent of the SO2 could be removed from the lead smelter sintering furnace tail gases, (2) regeneration of the citrate solution with H2S and precipitation of sulfur in conventional stirred vessels was readily controlled and highly efficient, (3) the precipitated sulfur could be continuously recovered as a 99.5-percent-pure product by kerosine flotation and melting, and (4) the 77- to 79-percent-H2S gas used for sulfur precipitation could be readily produced from pilot plant product sulfur, natural gas, and steam. Projected operating costs, including capital charges, for a citrate plant, installed at a 118 000-tonne-per-year lead smelter and treating 49 271 standard meters cubed per hour of lead smelter sintering furnace tail gas, are estimated to be $384 per tonne of sulfur.

Jan 1, 1976

By W. N. Lacey, B. H. Sage

In recent years there has been an increase of interest in the flow of gases at relatively high pressures. Hydrodynamic calculation of the energy losses in the flow of gases in conduits, as well as through the porous solid materials constituting natural petroleum reservoirs, requires a knowledge of the viscosity of the fluid at the pressure and temperature involved. Although there are numerous publications concerning the absolute viscosity † of hydrocarbon gases at atmospheric pressure, there appears to be little information available relating to the effect of pressure upon the viscosity of these gases. Voge133 determined the viscosity of methane at 32° F. and atmospheric pressure. His measurements at 32° F. were later substantiated by the measurements of Rankine and Smith20 at 63° and 212° F. Ishida14 also reported values for the viscosity of methane at atmospheric pressure. Trautz and Kurz30 measured the viscosity of propane at atmospheric pressure, from 83° to 530°F., by the use of a short capillary tube. Rap-penecker2' determined the viscosity of gaseous isopentane at elevated temperatures. Day6 made an accurate investigation of the effect of pressure upon the viscosity of n-pentane and isopentane at pressures from 2 lb. per sq. in.‡ to the vapor pressure at 77° F. (approximately 9.8 and 13.3 lb. per sq. in., respectively). Earhart7 reported data upon the viscosity of several natural gases measured by the long capillary-tube method. The viscosity of air, at atmospheric pressure and 73.4° F., was measured by Harrington9 by the rotating-cylinder method. Kellstrom15 has rec,ently made an elaborate investigation of the viscosity of air at atmospheric pressure. The latter work is perhaps the most accurate investigation of the viscosity of a gas that has been made.

Jan 1, 1938

By F. J. Williams

BARITE, naturally occurring barium sulphate, is the chief barium mineral that is produced commercially. Barite is also called "barytes," "heavy spar," sometimes "baryta" and, locally in Missouri, "tiff." Pure barite is white, opaque to transparent. It crystallizes in the orthorhombic system, frequently with twinning. Impurities cause a wide variation in color, commonly buff, gray and white with irregular reddish iron stains. Less frequently found are shades of yellow, green, blue, brown, and black. The rock is brittle and breaks with an uneven fracture, although specimens from some of the residual deposits, particularly in Missouri, appear to have a cleavage due to the separation of the different layers of deposition. The hardness varies from 2.5 to 3.5 on Mohs' scale and different localities are said to produce either "hard" or "soft" barite. This generally refers to the ease of grinding of the product. The specific gravity of pure barite is 4.5 and this will vary downward, depending on the impurities present. The mineral has a white streak and a pearly to vitreous or sometimes stony luster. Pure barite contains 65.7 pct BaO and 34.3 pct SO3. Witherite, native barium carbonate, is not mined in the United States at the present time although a number of occurrences have been reported. A small quantity of witherite has been removed from a mine at El Portal, California, but the area high in witherite was small and soon depleted. The bulk of the deposit is predominantly barite. Great Britain is the world source of witherite and small quantities are imported into the United States. DISTRIBUTION OF DEPOSITS Occurrence of barite is widespread; it has been reported on all the continents and in all the major countries of the world. Deposits vary from those containing millions of tons down to scattered rock fragments

Jan 1, 1949

By M. H. Caron

D. C. Ralston—The fact that none of the organizations that have worked on these ammoniacal leaching processes have contributed discussion of Mr. Caron's papers today is a matter of some disappointment. Adaptations, modifications and improvements have been made by several organizations or individuals and to complete the record I want to document a number of them. The Nicaro Nickel Co. operated a Government owned plant at Nicaro, Oriente, Cuba, during the past war. A report on the project was written for Reconstruction Finance Corp. and is in the document file collected by the Office of Technical Services, Commerce Department and filed with the Library of Congress, where it can be consulted or bibliofilm or photostat copies obtained by asking for copies of PB 97271. Nicaro Nickel Co. has obtained a series of U.S. Patents, my list (probably incomplete) of which bears the following numbers: 2,400,098; 2,400,114; 2,400,115; 2,400,461; 2,400,612; 2,458,902 and 2,473,795. International Nickel Co. has also studied the problem and U.S. Patent 2,478,942 shows that some of the complications involving occasional low extractions have been unraveled. Forward, Samis, and Kudryk, of the University of British Columbia, have also published a study of copper-nickel sulphide concentrate.' Others are interested and it is evident that this type of hydrometallurgy is likely to find a happy application in the not-too-far distant future. Caron's two papers practically amount to a summation of his life's work on the important subject of nickeliferous iron ores and the American Institute of Mining and Metallurgical Engineers is fortunate to have been chosen the medium of publication. M. Rey—The ammonia leaching process has been the subject of certain studies in New Caledonia, but at the present time, the conditions are not very favorable to its adoption. The process is a combination of a thermal and a hydrometallurgical process. As a result, the first costs and the operative costs are rather high. To counteract this unfavorable situation, it would be necessary to make a very high extraction. But unfortunately, the process is delicate and in spite of all of Caron's valuable work, there are still many unknown factors. It is difficult to obtain regularly a high extraction, exceeding 75 to 80 pct. It would be interesting to have the opinion of Inter-national Nickel on the process and to know what the Dutch are doing in Celebes. M. H. Caron (author's reply)—I am quite familiar with the different types of nickel and cobalt ores as found on New Caledonia, and it may be pointed out that the Celebes ores are quite the same in their properties. Their behavior when treating the ores by the ammonia-leaching process is also alike and in my opinion, there is no reason why a high extraction of the New Caledonian ores could not be obtained if the process is properly applied. For the sake of completeness I may add that one of my patents has not been discussed in the papers. This patent deals particularly with the treatment of serpentine nickel ores. (Netherlands No. 62693 40a, French No. 965.786 April 21. 1948. and Cuban No. 13.625 Jan. 1950.)

Jan 1, 1951

By M. H. Caron

D. C. Ralston—The fact that none of the organizations that have worked on these ammoniacal leaching processes have contributed discussion of Mr. Caron's papers today is a matter of some disappointment. Adaptations, modifications and improvements have been made by several organizations or individuals and to complete the record I want to document a number of them. The Nicaro Nickel Co. operated a Government owned plant at Nicaro, Oriente, Cuba, during the past war. A report on the project was written for Reconstruction Finance Corp. and is in the document file collected by the Office of Technical Services, Commerce Department and filed with the Library of Congress, where it can be consulted or bibliofilm or photostat copies obtained by asking for copies of PB 97271. Nicaro Nickel Co. has obtained a series of U.S. Patents, my list (probably incomplete) of which bears the following numbers: 2,400,098; 2,400,114; 2,400,115; 2,400,461; 2,400,612; 2,458,902 and 2,473,795. International Nickel Co. has also studied the problem and U.S. Patent 2,478,942 shows that some of the complications involving occasional low extractions have been unraveled. Forward, Samis, and Kudryk, of the University of British Columbia, have also published a study of copper-nickel sulphide concentrate.' Others are interested and it is evident that this type of hydrometallurgy is likely to find a happy application in the not-too-far distant future. Caron's two papers practically amount to a summation of his life's work on the important subject of nickeliferous iron ores and the American Institute of Mining and Metallurgical Engineers is fortunate to have been chosen the medium of publication. M. Rey—The ammonia leaching process has been the subject of certain studies in New Caledonia, but at the present time, the conditions are not very favorable to its adoption. The process is a combination of a thermal and a hydrometallurgical process. As a result, the first costs and the operative costs are rather high. To counteract this unfavorable situation, it would be necessary to make a very high extraction. But unfortunately, the process is delicate and in spite of all of Caron's valuable work, there are still many unknown factors. It is difficult to obtain regularly a high extraction, exceeding 75 to 80 pct. It would be interesting to have the opinion of Inter-national Nickel on the process and to know what the Dutch are doing in Celebes. M. H. Caron (author's reply)—I am quite familiar with the different types of nickel and cobalt ores as found on New Caledonia, and it may be pointed out that the Celebes ores are quite the same in their properties. Their behavior when treating the ores by the ammonia-leaching process is also alike and in my opinion, there is no reason why a high extraction of the New Caledonian ores could not be obtained if the process is properly applied. For the sake of completeness I may add that one of my patents has not been discussed in the papers. This patent deals particularly with the treatment of serpentine nickel ores. (Netherlands No. 62693 40a, French No. 965.786 April 21. 1948. and Cuban No. 13.625 Jan. 1950.) O F. A. Forward, C. S. Samis, and V. Kudryk: Trans. Canadian Institute of Mining and Metallurgy. (1948) 151 (Bull. 434) 350-355.

Jan 1, 1951

By William H. R. Gibney

Pine Point Mines is located in the Canadian Northwest Territories about 1,200 kilometers north of Edmonton, Alberta, close to the south shore of Great Slave Lake. Originally staked in 1898 by prospectors en route to the Dondike gold rush, it was not until the mid-1940's that large scale exploration was undertaken and Pine Point Mines Limited was formed. Work was suspended in 1954 while studies were made to resolve one of the main problems, transportation. In 1961, under the Canadian Government "Roads to Resources" program, agreement was reached for the construction of the Great Slave Lake Railroad and plans made to put the property into production. A townsite was established in 1963 and plant construction commenced. The first production was in the form of high grade ore which was shipped to Kimberley, B.C. for concentration starting in late 1964. The Pine Point concentrator started up in late 1965 when hydroelectric power became available. Initially designed for 4,540 metric ton per day, facilities were expanded to a designed 7,250 metric ton per day in 1969. Problems associated with mining operations at Pine Point are not unique but are augmented by the isolation, climatic conditions, topography, high water table and spread out nature of the operation. Maintenance of a reasonably stable work force is the number one problem but this is gradually being overcome as more local people are trained and oriented from a nomadic type life to an industrial society. The purpose of this paper is to give a general description of the mining operations of Pine Point Mines Limited and to review some of the problems encountered in the operation along with problems associated with northern operations.

Jan 1, 1970

By A. W. Cochardt

THERE are a number of effects that can cause material damping or internal friction. Some of these are frequency dependent, such as the thermo-elastic effect' and the stress-induced ordering.' Others depend on the amplitude of vibration, i.e., the damping related to the motion of dislocations3 and that due to magneto-mechanical hysteresis.' While many of these effects have been studied, only the magneto-mechanical effect has found extensive practical application. It is the principal source of damping in the current blade material in steam turbines.A magneto-mechanical hysteresis loop is seen in Fig. 1. If an unmagnetized, polycrystalline wire of a material exhibiting magneto-mechanical hysteresis, such as an Fe-14 pct A1 alloy, is twisted in torsion, a relation between shear stress and shear strain y is observed as indicated. The stress-strain curve does not follow Hooke's law -dashed line. Instead, the strain y increases nonlinearly and partly irreversibly, due to the motion of ferromagnetic domain walls,* until a critical stress is reached, which in this case is about 3,500 psi. If the applied stress is raised further, the strain appears to increase linearly and reversibly in accordance with Hooke's law, since all domains are now aligned in easy directions of magnetization nearest to the direction of the applied stress, and plastic flow has not yet started noticeably. On removing the applied stress, a remanent shear strain y, is observed, which is related to the irreversible magnetostriction of the material.' The energy dissipated in the material during a stress-strain cycle is proportional to the critical stress t, and the remanent magnetostrictive shear strain 7,. The purpose of this investigation was to make a survey of the magneto-mechanical damping of ferro-

Jan 1, 1957

By K. A. Johnson, F. H. Ellinger, C. C. Land

The Pu-La alloy systenz has been studied by thertnal, tnzcrographic, and X-ray diffraction methods. It is churacterized by a liquid miscibility gap, a maximum solubility of about 20 ut. pct PM in y lanthunum and 19 at. pct PI* in 0 lanthanum, very little soluibility of lanthanum in the plulonium allotropes, and the absence of intermediate phases. THE existence of immiscible liquids in the Pu-La system has been reported by Schonfeld.1 A tentative phase diagram based on the results of thermal-analysis experiments has been constructed by Poole et a1 2 This diagram shows a liquid immiscibility loop with a monotectic at 77 at. pct La and 846°C. 7 lanthanum is shown to dissolve 20 at. pct Pu and to decompose by an inverse peritectic reaction (y La = L , + p La) at about 82 at, pct La and 833°C. The ß lanthanum solvus was not determined, but the thermal work indicated a maximum solubility of 16 at. pct Pu in ß lanthanum. The present investigation has defined the solubility limits of plutonium in y lanthanum and 0 lanthanum, and, with the exception of minor discrepancies, has verified the results of Poole et al. 1) EXPERIMENTAL The electrolytic plutonium melting stocks were better than 99.9 wt pct pure, the main impurities being 90 ppm Fe and 50 ppm W. The lanthanum melting stocks, supplied by Research Chemicals and the Cerium Metals Corp., were about 99 wt pct pure, the main impurity detected by our spectrochemical analysis being 2000 ppm Fe. The components for each alloy button (-5 g) were weighed on an analytical balance and were melted together in a conventional arc furnace. If no significant weight loss occurred during melting, the as-weighed

Jan 1, 1968

By C. P. Watson

Economics has been defined as the useful application of wealth or material resources. The search of alchemists in the Middle Ages for s formula by which base metals might be transmuted into gold was no more intensive than has been the search by all branches of the oil industry for methods whereby the rnatcrial resources of West Texas in the nature of sulfur-bearing oil might be usefully applied. The purpose of this paper is to present in brief space developments that are conceded to possess economic significance. History The first discovery of oil in commercial quantities in the Permian Basin of West Texas was the Westbrook field in Mitchell County in 1920. Three years later the discovery well in the Big Lake field was cornpleted as a small pumper (70 bbl.) at a depth of 3028 ft. In 1925, discovery of the Powell or World pool in Crockett County stimulated activities in the Permian Basin, further establishing the importance of the Permian limestones as sources of production. The years 1925 and 1926 were marked by a period of extensive leasing and drilling activities. At the close of 1926 more than 7,000,000 acres had been leased and discovery wells completed in the Hurdle, Hendricksand Yates fields, definitely establishing the importance of the Permian Basin as a source of production from free-flowing wells. Review of Fields The producing fields in the Permian Basin are grouped on three distinct lines of folding. These may be separately identified as the Big Lake-Powell fold; the Yates, Hurdle, and Church-McElroy area and the Winkler County development. Production is derived from a porous limestone stratigraphically uniform, encountered at depths varying from 900 to 3100 ft. Lenticular sand bodies above the lime in Howard County have resulted in the

Jan 1, 1928

THE Nominating Committee appointed at the Division meeting in October and consisting of Frank A. Herald, A. W. Peake, C. R. McCollom, Joseph Jensen, H. W. Camp, C. P. Watson, F. Julius Fohs, George Otis Smith, J. B. Umpleby, J. M. Lovejoy and A. W. Ambrose, have presented the following ticket for the year 1929: Chairman, Joseph B. Umpleby; associate chairman, A. C. Rubel; secretary-treasurer, R. Van A. Mills; vice-chairman for Economics, Warren A.. Sinshein~er; vice-chairman for Engineering Education, H. C. George; vice-chairman for Engineering Research, Harry H. Hill; vice-chairman for Production, C. P. Watson;vice-chairman for Refinery Engineering, A. D. David. For Production Engineering Charles V. Millikan. is named vicechairman, with ,Charles E. Beecher, Glenn D. Robertson and W. W. Scott as associate vice-chairmen. The Executive Committee named is to consist of Joseph B. Umpleby, chairman with A. W. Ambrose, Charles E. Beecher, A. D. David, Glenn D. Robertson, H. C. George, Harry H. Hill, John M. Lovejoy, Charles V. Millikan, R. Van A. Mills, Earl Oliver, A. W. Peake, A. C. Rubel, W. W. Scott, Warren A. Sinsheimer and .C. P. Watson, members. Ballots will be mailed to members of the Division.

Jan 1, 1928

By J. P. BONARDI, William F. Boericke

BOULDER COUNTY, Colorado, ranked during the war years and until the end of 1918 as one of the foremost tungsten-producing districts of the world. In 1919 production fell off drastically, due to heavy importations of foreign ores from China, Burma and South America. So large were the imports that even after the enactment of a protective tariff in 1922 of 45c. per lb. on tungsten metal, equivalent to $7.14 per unit (201b.) of tungstic acid? (WO,), the stocks of metal in this country were extensive enough to supply the demands of industry, and prevent general resumption of mining by domestic producers. Even today there are only two producers in the Boulder district though at one time as many as twenty separate companies were in operation. About the same ratio holds for other tungsten-producing districts in the country, including California and Nevada. Total consumption of tungsten concentrate in terms of 60 per cent WO2 in the United States amounted to approximately 3790 tons in 1928, according to Frank L. Hess.' Of this amount, domestic mines contributed 1290 tons, and the rest, 2500 tons, was imported. Yet in 1917, with tungsten concentrate selling at $20 per unit, the Boulder district alone produced 2707 tons, indicating the effect of enhanced ore price upon production. It is believed by American tungsten miners that, given a sufficiently high tariff, all the demands of industry can be met by domestic production without placing a prohibitive burden on consumers. For instance, in steel manufacturing the percentage of tungsten entering into the manufacture is so small that, ?regardless of cost, it can constitute but a small fraction of the cost of steel to the buyer.

Jan 1, 1929

By J. G. Bartram

Jan 1, 1934

IN THE early evening of October 15, 1954, a large specially designed truck, convoyed by a second smaller one, arrived at Silver Bell, Arizona, completing a ten-hour 110-mile journey from Phoenix. The big truck was driven through gaps left in a previously prepared concrete foundation, the load was jacked up, the large girders that constituted the bed of the truck were pulled away, and the load was then lowered into place on the foundation. A crew of two men, the two truck drivers, finished the job in a little more than an hour. When they were through, a complete and attractive three-bedroom house, prefabricated in Phoenix, was almost ready for occupancy. About all that remained to do was to connect the utilities-water, electricity, plumbing, and gas. The kitchen and bathroom equipment and appointments were superior in every respect, and there was a built-in car port for the automobile of the prospective residents. This family domicile was one of more than one hundred, each averaging about $8,000 in cost, that the American Smelting and Refining Company has provided for its employees engaged in mining and milling 7,500 tons per day of low-grade Porphyry copper ore. Aside from the fact that it is more economical-partly because of the variety of union craftsmen needed to build and equip a house-to do the work in a city 110 miles away, the significant point is the high quality of housing that is provided for what may be called in nostalgic vein the "mining camp" of 1955. Silver Bell is typical of all the Porphyries in this respect though the community is relatively small. At San Manuel

Jan 1, 1957

Wartime geological studies by the U. S. Geological Survey and subsequent drilling carried on by the Bureau of Mines disclosed new ore in the Illinois-Wisconsin zinc field. As a result, several companies are carrying on drilling programs to locate and define new ore bodies. The Vinegar Hill company, which operates a custom mill to handle ores from various sources, now employs about fifty men in production at their Andrews mine. The ore is usually found in a 200-ft horizon below the surface. Water problems are not serious. Commercial-grade ore ranges up to 8 and 9 per-cent zinc and the cut off is approximately 41/2 percent.

Jan 1, 1948

By G. W. Healy, W. Craft, D. C. Hilty

By means of a theoretical extension of the Cr-C temperature relation in molten chromium steels to low chromium contents and by a correlation of the ratios of chromium to iron in the slag and metal, a method has been developed for estimating the amount of metallic oxidation during the oxidizing period of a chromium steel heat. Application of this method has indicated that due to temperature limitations metallic oxidation may be excessive for very low carbon steels charged with more than a small amount of chromium. IN the melting and refining of chromium steels the oxidation of carbon to a low level is accompanied by the oxidation of chromium and iron in considerable amounts. For the subsequent recovery of chromium and associated iron from the slag, the amounts of metal oxidized must be known for efficient reduction and control of composition. Further, in order to arrive at an accurate understanding of the process, so that chromium-bearing scrap can be used effectively, information is required on the relation between composition of the charge and weight of metal oxidized to reach the desired carbon content. Crafts and Rassbach1 recently developed an empirical relation between chromium, iron, and manganese oxidized per ton of steel charged, and final carbon content and temperature. This relation did not show any dependence on amount of chromium charged. However, it was felt that such a dependence might be present, so a further analysis of the data was undertaken. Cr-C Relation at Low Chromium Levels Crafts and Rassbach's results were based on temperatures estimated from the Cr-C relation previously established experimentally by Hilty,2 and on a single temperature observation (immersion thermocouple) on a heat made at low temperature from a charge of carbon steel scrap containing only a small amount of residual chromium. The temperatures estimated from the Cr-C relation were for heats charged with chromium-bearing scrap and which contained substantial amounts of chromium (2 to 10 pct) at the end of the oxidizing period. No data, other than that from the low temperature heat just mentioned, were available for the low and intermediate chromium ranges. In order to extend the range in which temperature may be estimated, the Cr-C relation requires further consideration. The Cr-C relation, expressed as suggests that carbon is zero at zero chromium in the bath. This is obviously absurd, because as chromium approaches zero the carbon content must approach the limit established by the Fe-C-O equilibrium. It is evident, therefore, that the Cr-C relation as defined by Eq. 1 is not valid below some minimum chromium content that may vary with temperature. On the other hand, it is probable that any such limiting chromium content is less than 4 pct at 3200°F, since the experimental data from which the Cr-C relation was derived included several observations at that level with no deviation. In any event, it is apparent that further evaluation of the results presented by Crafts and Rassbach is dependent upon a means for estimating the Cr-C temperature relation in the low chromium region. From the observations of Chen and Chipman9 and thermodynamic data given in Basic Open Hearth Steelmaking,4 the following relation can be calculated for melts containing small amounts of chromium and carbon assuming a carbon monoxide pressure of 1 atm: % Cr -21,250 K' = (%C)2; logK1 == —t— +13.88 [2] Moreover, by plotting Eq. 2 for any given temperature on cartesian coordinates, it can be extrapolated graphically to the limiting carbon content at zero chromium for the specified temperature without serious complications. By means of Eq. 2 and its extrapolation, the Cr-C temperature relations originally established experi-

Jan 1, 1954

By F. A. Hames, D. S. Eppelsheimer

The ferromagnetic copper-manganese-aluminum and copper-manganese-tin alloys (Heusler alloys) owe their ferromagnetism to the beta phases (body-centered cubic structure) in their respective systems.l,2,3 The ternary beta phase regions in these systems are extensions of the beta fields of the binary copper-aluminum and copper-tin systems into the ternary models of the copper-manganese-aluminum and copper-manganese-tin systems respectively. X ray analysis has indicated the presence of long-range order in the more strongly magnetic alloys.3,4,5 The ideal ordered structure is obtained in alloys of compositions Cu2MnAl and Cu2MnSn; the copper atoms occupy positions at cube centers while the aluminum (tin) and manganese atoms alternate at cube corners. This atomic arrangement is illustrated in Fig 1. The compositions Cu2MnAl and Cu2MnSn are also those that show maximum magnetic saturation moment. 3,4,6,7 Departures from these compositions result in a decrease in the degree of order attainable and a decrease in magnetic saturation moment. In view of the chemical similarities of aluminum, tin, indium, and gallium, and the existence of beta phases in the binary systems copper-indium and copper-gallium, it may be suspected that ternary beta phases exist in the systems copper-manganese-indium and copper-manganese-gallium, and that these are ferromagnetic. The purpose of this investigation was to determine whether ferromagnetic beta phases exist in the systems copper-manganese-indium and copper-manganese-gallium analogous to the ferromagnetic beta phases in the systems copper-manganese-aluminum and copper-manganese-tin. Previous Work At the time this investigation was started no information could be found regarding the constitution of copper-manganese-indium and copper-manganese-gallium alloys, nor of the binary manganese-indium and man-

Jan 1, 1950