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By P. F. Ahner, Leonidas Petrakis, Fred E. Kiviat

High gradient magnetic separations (HGMS) is a recently developed technique in which magnetic micron-size particles contained in a flowing fluid medium can be extracted from that medium. HGMS is presently utilized on a commercial scale in the kaolin processing and steel industries, and is being investigated for solid-liquid separations in numerous other processes. The performance characteristics of HGMS in the kaolin and steel industries are briefly summarized. A discussion of HGMS performance with respect to solids removal in a coal liquefaction process is presented to illustrate its applicability to difficult solid-liquid separations. Here, the properties of the solids suspended in the liquified coal are such that the HGMS separator achieves over 90% solids removal. The optimization of the HGMS operating parameters to yield these results will be discussed. To further illustrate the potential of HGMS, its performance with respect to the removal of oil and solids (over 98% removal) from a petroleum refinery process water effluent stream will be briefly considered.

Jan 1, 1980

By Robert H. Richards

My first paper, read at the Cobalt Meeting of the Institute,' July, 1907, dealt with the behavior of a small Wilfley table when collceiltrating galena from quartz, the table being fed with natural products, with sized products, and with classified products. Since galena, having a specific gravity of 7.5, is among the heaviest minerals ordinarily concentrated by Wilfley table, it was desirable that a similar set of tests upon a mineral of lighter weight should be made. Chalcopyrite, of a specific gravity of 4, would have been the best mineral for this purpose, on account of its great importance as an economic mineral, but in carrying out the test I was obliged to content myself with a cupriferous pyrite, the specific gravity of which was 4.68 and the content in copper 8.80 per cent. Through the kindness of H. 0. Cummins, this material was obtained from Shasta, Cal., in very pure, clean, homogeneous condition. It was broken by rolls to 2 mm. in size, taking care to make a minimum of slimes. The quartz used to mix with it was pure, white, New England quartz, broken in the same way to the same size. In studying the accompanying tables, it should be borne in mind that the material concentrated was of low copper-content, and in many cases the quantity fed to the machine was 1 kg. or less. As a consequence of the smallness of the quantity treated it was very difficult to adjust the table and get it in condition to do its best work before the feed became exhausted, and for this reason many results were obtained which appear irregular.

Jan 1, 1909

By J. J. K. Daemen, C. Fairhurst

Introduction The stress field around a supported tunnel can be considered as being composed of: i) the virgin (pre-mining) stress in the rock ii) the (elastic) change in this stress field caused by creating the opening iii) the (time-dependent ) change in the stress field produced by (i) and (ii) as a section of the rock breaks up iv) the (time-dependent) influence of the stress build-up in the support. Several authors have examined the conditions necessary to produce static equilibrium between the support, the rock, and the regional (in-situ) stress field. The analysis used by Labasse (1) is typical. Consider a circular tunnel radius R in a hydrostatic stress field (P), and a radial pressure pi exerted by the support. According to Labasse, the radius ‘b’ to which the rock will break* for a given support pressure, pi, can be calculated from: - the equilibrium equation: [ ] As a zone of broken rock develops around the opening, the stress circle for a point on the elastic-broken rock boundary moves to the right in the Mohr diagram until the radial stress in the broken zone s equal to the radial stress in the elastic zone.

Jan 1, 1971

By Stuart McGill

This case-study of the financing of the Ok Tedi project illustrates the nature of project financing and outlines the arrangements made in the case of this project; it also demonstrates that the limitation of financial exposure is an important goal for Governments involved in developing the resources sector. The account includes a chronological description of the process by which the sponsors prepared for the financing of the project and the lenders became involved in it. The type of security arid loan documentation required for such financing is described, together with a broad analysis of their content and the manner in which the various risks involved in development are apportioned among the sponsors and lenders. The ability to apportion and limit financial liability is an important development for the owners of capital and resources.

Jan 1, 1985

By Horace Tharp Mann

Jan 1, 1926

By W. A. LaVenue, W. M. Houston

Pebble phosphate mines of Florida have been established from south of Hardee County to north of the Georgia state line, a distance of over 200 miles. Mining has been carried out on an ever-increasing scale since 1885, but phosphate deposits that can be mined on the economical standards of today, are confined in a roughly circular area about 30 miles in diameter, generally within Polk and Hillsborough Counties, in the central part of the State. The phosphate deposit, which is in the Bone Valley formation of Pliocene age, is covered by Pleistocene terrace deposits of unconsolidated quartz sand. The matrix is composed of approximately 1/3 clay slimes, 1/3 silica sand and 1/3 phosphate pebbles. The phosphate usually occurs as rounded pebbles, ranging in size from about 1 in. down to approximately 400 mesh. The phosphate may vary from well-defined hard pebbles to soft weathered rock. The color and character of the phosphate will range from smooth buff pebbles to black and white "salt-and- pepper rock." The screen size distribution varies considerably between locations; the recoverable phosphate may extend down to the 400-mesh size in some areas, while in others the phosphate may cut off sharply at about 35 mesh.

Jan 11, 1962

By W. H. Adams

Among the engineering plants with new features and deserving details which are constantly being brought to the working stage in the Southern States by the generous expenditure of capital, none can exceed in interest, whether to the public or the profession, the incline-railway built from base to summit of Lookout Mountain, near Chattanooga, Tennessee. Much geological and historical interest centers in this section of the middle mountain-country. Of its geology, the Transactions of the Institute contain many particulars. Of its history, the most

Jan 1, 1888

By Eugene H. Cowles

Now that a determined public effort is being made on this side of the Atlantic to create a steel ship-building industry, the materials that are demanded for this purpose assume a new interest to the American metallurgist. In the past, the uses of metals in this country have been almost exclusively connected with the land, while in England their application to marine purposes has been equal in importance to that on shore. In the future the same should be the case here. This is the reason for bringing a somewhat nautical or rather naval topic before a body the chief interests of which are supposed to lie in the mines and mountains of the interior of the country. A modern war-ship or " ocean-grayhound" (like the City of Paris) is an epitome of philosophy and human skill. In her graceful lines we have, as Ruskin might quaintly say, a " builded geometry ;" while in her wonderful machinery for motion, offensive and defensive, we have the summation of the ideas of a host of students who have, at one time or another, during the course of a hundred years of her evolution, contributed their intellectual mites to render her a thing of beauty and of power. Notwithstanding her present perfection, the modern ship contains room for further improvement. One of the most important things about her is the propeller. This active member is of more impor-

Jan 1, 1890

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 L. P. Teas

The year 1931 has been one of unusual interest in Gulf Coast petroleum development, not so much because of the number of new prospects discovered, for apparently none of any present distinction have been found, but because of the discovery of so many new oil fields and the proving of so many old prospects. During the year 10 new oil fields have been found on the Coast; five in Louisiana and five in Texas. Two suspected salt domes were proven by the drill. Production dropped from a daily average of 192,000 to 162,670 bbl., or an average of 58 bbl. for each producing well, and active operations from 189 to 119. During 1931 the Coast produced approximately 48,600,000 bbl., or 44 per cent less than in 1930, when 86,500,000 bbl. were produced. The daily return at the beginning of the year was $192,000 and at the end only $126,780, the price having dropped from $1 for A grade and a range of $0.75 to $1.22 for B grade to a price range of 70 to 86c, or an average of 78c $ per barrel at the end of 1931. The average Coastal well produced 17,400 bbl. of oil during 1931. During the year development in the old fields has continued active at Barber's Hill only, although some work is in progress at Humble, Pierce Junction, Refugio and Pettus. Clear Lake is active but the large ownerships will prevent the "boom" type of field. Production is being held fairly steady at Barber's Hill and Pierce Junction, but has declined rapidly during the year at Refugio, Humble, and to a lesser degree at Pettus. The 6000-ft. production at Barber's Hill has shown a decided drop during the year and has not measured up to expectations.

Jan 1, 1932

By N. B. Wittman

Among the objects of interest which the members of the Institute are invited to examine in connection with this meeting is the Brown segmental wire-gun, which will be seen in process of construction at the works of the Pennsylvania Diamond Drill and Manufacturing Company, at Birdsboro. This is a 5-inch breech-loading (highpower) rifle, 19 feet long, constructed upon the system of Mr. J. H. Brown, an inventor of recognized genius in many branches of mechanical industry, and under the engineering direction of Lieutenant G. N. Whistler, Fifth U. S. Artillery. The system consists essentially of the subdivision of the inner core or tube of the gun, which takes up the initial compression, into longitudinal segments of such size that a higher physical condition and degree of special elasticity may be set up therein than it is possible to produce in the larger masses of metal heretofore used for the tube of the modern high-power cannon. The process consists in winding layers of square steel wire, subjected to a constant tension of 130,000 pounds per square inch, around these segments, which, when so held together, form the tube of the gun. A lining-tube may or may not be used. The steel segments used in the gun now under construction are 18 feet 4 inches long, and 3 inches thick at the breech, from which they taper to 0.8 inches at the muzzle. The physical condition of the segments has been determined by test-pieces, cut from each end of each segment, which show the following characteristics: Tensile strength, 165,000 pounds per square inch. Elastic limit, 105,000 pounds per square inch. Elongation at rupture, 14 per cent. in 2 inches. They are of crucible chrome steel, made by the Carpenter Steel Works, at Reading, Pa. The wire which holds them together has 0.005 square inches sectional area and is wound under a constant tension of 650 pounds on each strand, equivalent to 130,000 pounds per square inch. The winding has been done by a machine designed

Jan 1, 1893

By Earle J. Klohn

Mining operations have been carried out in British Columbia since the time of the first settlers in the area. The early developments were mainly small volume, high-grade operations, producing small quantities of tailings wastes. In these early days the nearest stream was a logical first choice for tailings disposal. Where streams suitable for accepting the tailings were not available or where streams crossing the International Border could not be used for this purpose, the nearest convenient land site was selected for storing the tailings. Old tailings waste piles exist at many locations in the Province and are readily evident, for example, in the Princeton and Hedley areas. Figs. 1 and 2 are photographs showing the present condition of two of these old tailings dams. [ ]

Jan 1, 1972

By J. E. Kemp

1. Situation.—From Monterey in the State of Nuevo Leon, the Sierra Madre mountains stretch away to the southeast and present a steep front to the northeast. The Monterey and Mexican Gulf railway. which connects Monterey with Tampico. follows their general line with its road-bed a few miles out from the foothills. At a distance of 100 miles from Monterey it passes through the town of Linares. and from Linares one can see far away to the southeast the peaks of another group of mountains rising from the general plateau and forming a more eastern

Jan 1, 1906

By F. E. Lucas

This paper is offered with considerable diflidence, since some of the statements made may not agree with the opinions of other members of the Institute. What I give is the result of some years of experience in the operation and construction of coke-ovens, and observation of plants in America and Europe. Although my title is " The Manufacture of Coke," I have found it impossible to do justice to the subject without touching on a number of points which, while not strictly involved in the making of coke, yet are of paramount importance from an economic standpoint. There are, indeed, many points of interest, on each of which a separate paper of considerable length might be written, but the scope of my paper will permit me only to touch lightly some of them, in the hope that what I say will promote a full discussion on the whole question. Those of us who are interested in the manufacture of coke are under an obligation to the American Institute of Mining Engineers, which has opened its meetings to the discussion of this subject. I do not believe that there is any question to-day more worthy or more in need of discussion. When geologists and mining-men tell us that, at the present rate of consumption, our coal-fields will be exhausted in a few generations, me should welcome any means that will conserve these deposits as far as possible, and give us the greatest amount of heat or power from every ton mined. I shall try to show that much can be done in this direction through the by-product coke-oven, and that it should stand second to none as an economic factor in the industrial world. I shall here deal exclusively with the by-product oven, except for the comparative statement I hare prepared, showing the saving to be effected by coking in by-product instead of beehive orens. It should be borne in mind that this comparison

Jan 1, 1913

By James P. Graham

In this paper the authors present the background information to preheating and its development and describe the facilities available at the British Carbonization Research Association. The results obtained at BCRA including those collected during commissioning of the new plant at BCRA are summarized and reference is made to the research work planned for the next stage. The enlarged test-plant facilities at the British Carbonization Research Association embrace both 10-t (4.2 m high) and 17-t (6.5 m high) test ovens and two types of preheater, the preheated coal being charged by either gravity or pipeline. During the commissioning of the new equipment, an extensive programme on preheating was initiated and the paper includes the results obtained so far. These cover tests on wet and preheated coals and commercial blends, the use of Rosin- and Cerchar-type preheaters and charging by both gravity and pipeline systems to the 10-t and 17-t ovens. Accordingly, for the first time a direct comparison is possible of both the performances of the plants and the qualities of the respective products. The paper also outlines the findings from a study of the carryover of solids during the charging of preheated coal and of the treatment of those solids.

Jan 1, 1977

By Thomas T., Read

IT will be recalled that the first professor of metallurgy in the United States, appointed in 1855, never really gave any instruction in metallurgy and gradually turned into a professor of mineralogy. Metallurgy was included with. mining in the early curricula, two students who took the B.S. in mining engineering from the Polytechnic College of Pennsylvania in 1862 wrote their graduation theses on the metallurgy of copper and zinc, respectively. Even after Columbia School of Mines established, in 1868, a separate curriculum leading to the Ph.B. degree in metallurgy, very few students elected it,* preferring to take the mining degree, since they received in its curriculum nearly all the metallurgical instruction they would have in the metallurgical curriculum. For many years a large proportion of the men who attained prominence in metallurgical enterprises had taken mining rather than metallurgical degrees. METALLURGY Clifton Sorby's study of thin sections of rocks under the micro¬scope, beginning in 1850, and its subsequent development by Zirkel and others, had made microscopic petrography a recog¬nized department of geological research as early as 1873. . It was inevitable that the idea of studying polished metal surfaces-¬under the microscope by reflected instead of transmitted light would occur to investigators. Sorby himself did it in 1864, and Adolph Martens and Floris Osmond may -be especially named among the many European workers who, by the late eighties, had so developed the, necessary techniques that they were able to photograph polished metal surfaces at magnifications as high

Jan 1, 1941

By W. J. Garmoe

Distinct areas of mineralized and non-mineralized brecciated rock are found in the Ontario Unit of the United Park City Mines. These breccias contain an appreciable fraction of the present ore reserves and probably will become even more important as deeper levels are developed. Three ages of breccia have been recognized in the Ontario Mine to date: ( 1) Pre-mineral breccia that may or may not be mineralized, (2) early post-mineral breccia with mineralized fragments, and ( 3) late post-mineral breccia that is younger than and cuts through ( 1) and (2) above. These age ,relations are known from detailed underground mapping. Locally, both pre-mineral and post-mineral breccias have sufficient lead-zinc-silver content, either as matrix or fragmental material, to constitute ore. Ore-grade breccias occur throughout a vertical range of over 1000 feet and are found in both the Humbug and Deseret formations from above the Ontario 1300 level to below the Ontario 2200 level. The mineralized breccias, which are difficult to distinguish on mine maps, are not well delineated by underground workings, and their horizontal outline and vertical extent are not known beyond the immediate mining areas. The greatest amount of truly mineralized breccia is exposed on the 2200 level.

Jan 1, 1968

Edward Halse, Puerto Berrio, Colombia, S. A. (communication to the Secretary): I have read with much pleasure the interesting and valuable paper by Mr. Kunz, and hope that the following brief notes, gathered a few years ago, while a resident in Mexico City, may help to elucidate the subjcct: Turquoise.—This was known to the Aztecs as Xihuitl. Santiago Ramirez states that they found it in the Cerro Xicohtzonc, close to Atzcapatzalco, a suburb of the City of Mexico (compare page 59). Opal.—This was known to the ancient Mexicans, for they named it mezcuitlatt (compare page 63). Jade.—Under this was iucluded a third mineral, prehnite, not mentioned by Mr. Kunz. According to James D. Dana, part of the "jade " of China is prehnite; and Humboldt informs us, in his work on New Spain, that the same species of jade is known in some parts of Mexico as mahagua (majagua ?). The same writer says, in his Views of the Cordilleras, that the Aztec name Tecpatl included flint, hornstone, and green jade; and finally, in his Travels in South America," he discusses the nature of the ancient amazon-stones, and declares them to have been made out of a jade resembling " compact feldspar," one of the constituents of the gabbro verde di Corsica. IIence those stones were probably composed of nephrite. According to Humboldt, the form given to them most frequently is that of the Babylomian cylinder, longitudinally perforated, and loaded with inscriptions and figures. They were also cut by the natives into very thin plates, perforated at the center, suspended by a thread, and worn as amulets. According to the historian Clavijero, the specific name given by the Aztecs to the nephritic stone (jadeite) was Quitzalitztli,

Jan 1, 1902

By R. F. Bell, L. W. Eastwood, R. W. James

Among those concerned with the annealing and heat-treating of aluminum and aluminum alloys, it is well known that after co1d-working a coarser grain is usually produced by slow heating than hy more rapid heating. Consequently, for the control of the grain size produced by annealing or heat-treating cold-worked aluminum and aluminum alloys, the heating rate is of considerable practical importance. References in the current literature on the effect of heating rate are numerous, but it appears neither necessary nor desirable to give here a review of the former nark done on this subject. It became evident during some preliminary work on the recrystallizn-tion of aluminium and aluminum alloys that the effect of heating rate depended upon the type of microstructure of the metal. This observation led to the following study of the relationship of the type of microstructure of the alloy to the effect of the heating rate. Materials Investigated Analyses of the aluminum and aluminium alloys investigatted are given in Table 1. Three classes of material are listed, as follows: Class I.— Belonging to the first class are pure aluminium and aluminium containing a second constituent that is soluble in the aluminium matrix at

Jan 1, 1939

By Joseph E. Pogue, F. G. Coqueron

Prior to 1934, published information covering expenditures by oil companies for properties, plant, and equipment and the residual investments in the various segments of the petroleum industry was not readily available. This paper presents an analysis of the funds invested by a selected group of oil companies during the years 1934 through 1942, based on an extensive study of the individual records of 30 oil companies. The sources, disposition, and characteristics of the capital employed by this group of companies are traced through a series of combined statements and appropriate charts, covering financial and operating data. The analysis of these statements not only constitutes a record useful for comparative purposes but also serves as a basis for a number of broad conclusions, as follows: 1. The petroleum industry generates the capital needed for its expansion almost entirely from its own operations and is therefore a singularly self-contained economic unit. 2. The long-term debt contained in the financial structure of the industry is small relative to the total capital employed, is less than the net working capital, and has increased but slightly during the period under review. 3. The capital expenditures of the group of 30 oil companies for 9 years amounted to 6.1 billion dollars, 58.3 per cent of which went into crude-oil producing facilities. The trend of this segment of expenditures has been downward since 1937. In 1942, expenditures for refining facilities increased sharply and for marketing facilities declined drastically. 4. The net working capital of the group increased 380 million dollars over the period, and the industry is in a favorable position of liquidity. The ratio of combined current assets to current liabilities was 3.21 at the close of the period. 5. The net income of the group displayed an upward trend for the period but with rather sharp cyclical fluctuations. 6. In 1942, Government funds entered the industry for the first time in substantial amounts and were utilized for the provision of war facilities needed for emergency use. 7. The group has paid out a relatively low percentage of net income in the form of dividends. For the period the average was 55 per cent of net income. 8. The rate of return on invested capital for the group averaged 6.4 per cent for the

Jan 1, 1944