Search Documents

By Sheldon P. Wirnpfen

AN extensive study of German underground manufacturing experience is being undertaken by the Air Materiel Command. Headquarters officials consider completely underground facilities one of the most effective means of protecting aircraft production against air attacks of the strength and type employed in World War II. Advantages accruing to underground manufacturing installations other than protection are, perhaps, a smaller maintenance problem and the possibility of using gravity flow on some production lines. Offsetting these advantages are the high cost of construction, problems of ventilation, and poor acoustics. Excavation costs might well be less than the cost of enclosing the same area on the surface, as new and better methods of rock drilling and transportation are developed. Certainly the amount of building materials used would be far less than in constructing a surface plant of the same dimensions. A fewer number of skilled workers would be required to perform the labor of excavation. Underground construction would

Jan 1, 1947

Jan 1, 1888

NORTH AMERICA. CANADA Canadian Army Overseas. Ball, H. D. Bridges. C. Butterill, H. J. If. Ladner, F. E. Lane, H. C. Alillar, W. A. ALBERTA Calgary.-Chonette, W. C. Clark, L. At. Corbett, C. S. de Hart, J. B. Dingman, C. W. Fath. A. E. Fulton. J. If. Cray, J. G. Johnson. R. V. McCutchin, J. A. *Slipper, S. E. Vin Buckirk H. A.

Jan 1, 1944

CONTENTS KANSAS-H. S. BRYANT 3 TEXAS, EXCEPT GULF COAST-M. C. CHENEY 14 GULF COAST-L. P. TEAS 21 TEXAS PANHANDLE-W. E. HUBBARD 29 LOUISIANA, ARKANSAS AND MISSISSIPPI L H. K. SHEARER 37 ROCKY MOUNTAINS-R. C. COFFIN 43 CALIFORNIA-V. H. WILHELM 51 MICHIGAN AND THE TRENTON FIELDS OF OHIO AND INDIANA-M. G. GULLEY 65 ILLINOIS, WESTERN KENTUCKY AND WESTERN INDIANA-A. H. BELL . . . 73

Jan 1, 1932

By J. V. Emmons

It has long been known that the outside skin of tool steel frequently exhibits properties widely different from the interior of the mass.

Jan 1, 1915

By R. C. Schmidt, B. E. Kennedy

The Mont Klahoyo magnetite deposit is located about 600 km (373 miles) northwest of Abidjan, Ivory Coast. During an exploration period ending in 1977 an international joint venture group investigated the deposit and proved reserves of 670 Mt (739 million short tons) grading 36% iron. The deposit occurs at the northeast end of the Baoubly-Kiriao chain of Precambrian iron formations with associated amphibolites, pyroxenites, and gneisses of the Liberian Shield. The ore body is represented by a highly metamorphosed banded quartz-magnetite iron formation with alternating beds of iron silicates and quartz-magnetite. Amphibolite-pyroxenites and sillimanite-cordierite-garnet gneisses form hanging and footwall rocks. The iron formation has been folded into an elongated, overturned 2-shaped major drag fold with axes trending and plunging approximately northeast. Beds are vertical or dip steeply to the southeast. The ore zone has an average thickness of 130 m (427 ft) and outcrops intermittently over a distance of approximately 5.5 km (3.4 miles). Based upon detailed studies of drill cores and the results of ore dressing test work, eight stratigraphic units, identified as K- 1 to K-8, are recognizable in the iron formation. Four interbedded units are low grade silicate zones (silicate facies) while the remaining quartz-magnetite units are oxide facies, representing the important Mont Klahoyo deposit ores. Ore-bearing "K" units are subdivided further into 11 ore types, based upon their specific lithologies, iron content, and concentration characteristics. Identification of these ore types proved particularly useful to mine planning and flowsheet design. A cap of oxidized material overlies the primary quartz- magnetite iron formation, but no enrichment has occurred. It is thought that the Mont Klahoyo iron formations were deposited chemically in a volcanic environment as a siliceous iron formation with volcanism the primary source of iron and silica. Metamorphism converted the siliceous iron formation to a coarse-grained, quartz-magnetite-silicate iron formation.

Jan 1, 1983

Jan 1, 1969

Jan 1, 1923

By Charles B. Dudley

DEAR SIR: It is now nearly three years since my first report to you on the subject of steel rails was written. That report, as you will remember, dealt principally with the question of the relation between the chemical composition and physical properties of steel rails end their power to resist crushing and fracture in actual service. Other matters were referred to or touched upon in that report, but the main question was, Why do some rails crush or break in service while others do not? Yon will doubtless remember that the principal conclusion arrived at was, that the softer rails are less liable to Crush or break in service than the hard ones. Or, in other words, so far as conclusions could be drawn from the chemical analysis and physical test of 25 samples of steel rails which had actually been in service, these conclusions were that those rails which have the smaller amounts of carbon, phosphorus, silicon, and manganese are less liable to crush or break in service than those which have larger amounts of these elements. Or, again, looked at in the light

Jan 1, 1881

[NORTH AMERICA ALASKA Anchorage.-Strandberg, H. Chlchagoff.-Russell, J. C. College.-Barber. R. J. Dorsh, J. B. Fox, E. F. Joesting, H. R. McAnerney, J., M. Douglas.-Cahill, W. E. Fairbanks.-Beistline, E. H. Crawford, J. D. Earling, R. B. Greves, J. H. Harris, Q. P., Jr. Henton, H. M. Herbert, C. F. Hester. W. B. Hopkins, J. E. Kreitlow, E. J. MacDonald, D., III March, J. P. Mathews, T. C.]

Jan 1, 1940

[NORTH AMERICA UNITED STATES ALABAMA AUBURN Sturm & O'Brien, Consult. Engrs. °Sturm, Rolland G. BESSEMER Granger, W. C. BIRMINGHAM Air Reduction Sales Crockett, John M. Amer. Cast Iron Pipe Co. Carter, Sam F., Jr. Donoho, C. K. Anderson Elec. Corp. Davis, Moss V. J. B. Clow & Sons Neptune, Maurice D. Connors Steel Div. °Sandelin, Robert W. Hayes Aircraft Corp. Ricketts, W. E., Jr. Willhelm, A. Clyde, Jr. McWaine Cast Iron King, O. H. Worthington, B. W. Shook & Fletcher Sup. Co. Gearhart, Thomas A. Southern Res. Inst. Dismukes, Edward B., Wheelahan, Edmund J. Thomas Foys Miller, Ralph M. Union Carbide Metals, Co. Brandler, Edgar A. U. S. Pipe & Fdry. Co. Clay, Donald H. Unaffiliated Berg, H. A. Caldwell, H. A. Gilmer, H. U. Harris, Thomas H. Templeton, J. B.]

Jan 1, 1961

By Paul Cook

THE ore deposit of the Buckhorn Mines Co., Buckhorn, Nev., is peculiar in being a shallow kaolinized mass of material with basalt walls, and having apparently no direct connection with any of the usual gold-bearing rocks. The average ore contains 16 per cent. waiter of hydration, and the cyaniding of this hydrous clayey material offered unusual difficulties as compared with the typical gold quartz ores of Nevada. The orebody was thoroughly developed; then the mill was built according to the latest cyanide .practice, with such changes as were thought to be demanded by the peculiar nature of this ore. Upon starting the mill, the ore proved more difficult to handle than had been anticipated. It is hoped that an account of how these difficulties were met may prove of interest to anyone having a clayey ore to handle and to the profession in general.

Jan 9, 1916

Jan 1, 1923

By Charles W. Dickson

Jan 1, 1904

Jan 1, 1920

By Ivan E. Goodner, Charles H. Fulton

The subject of the constitution of copper-iron mattes has received considerable attention in recent years by Keller,' Belles,2 Hofman,3 and Gibb and Philp.4 Still more recently Friedrich, Röntgen, Wiedmann, Heyn and Bauer, and Leroux have published, in some instances, elaborate researches on the various systems of the sulphides, and the snlphides and their respective metals, which enter into the constitution of mattes, and have added very greatly to the knowledge of the subject. The work of Friedrich has been especially fruitful. But to' date no effort has been made to correlate the data obtained in the latter researches and apply them to the study of the product called " matte," which is made in such large quantities by copper- and lead-smelters. In this paper we propose to determine, by metallographic and chemical means, the constitution of copper-iron and copper-lead-iron mattes in the light of the recent data above mentioned. We do not discuss copper-nickel mattes or speisses (artificial arsenides). The paper is divided into three sections: I. A review and discussion of the various binary systems of the metallic sulphides, and the binary systems of various metals and their respective sulphides entering into the constitution of mattes; also a discussion of the physical properties of these sulphides. II. A description of the results obtained from the chemical and microscopic examinations of the samples of copper-iron and copper-lead-iron matte obtained from various plants.

Jan 1, 1909

Jan 1, 1896

By Richard W. Smith

KYANITE, long known to occur in Georgia, did not excite commercial interest until about 1930. Investigations revealed two main types of deposits: (1) separate kyanite crystals embedded in mica schist; and (2) crystal aggregates of kyanite associated with quartz in small and very irregular veins. The second kind at first sight appeared to be the best source of supply. Large boulders or dornicks of kyanite with more or less quartz were found on the surface at many places throughout the Piedmont and Highland sections of the state, but prospecting failed to disclose a sizable vein. These dornicks seem to be a surface accumula-tion from small veins or lens-shaped masses not more than one or two feet thick, and with a horizontal extent of not' more than a few feet. The larger surface accumulation of kyanite dornicks, where not too badly stained by iron oxide, may prove to be marketable, but it is extremely doubtful whether a vein large enough to mine will ever be found. In 1932 deposits of the kyanite-mica schist were known to occur in two places northwest of Clarkesville, in Habersham County. In 1934, at the request of and in cooperation with the Georgia Geological Survey, the United States Geological Survey made a thorough investigation2 of the deposits and found that the two known areas of kyanite-mica schist in Habersham County were but a part of an unsymmetrical, U-shaped belt (Fig. 1) with a western limb extending into Rabun County and somewhat longer than the eastern limb. The total length of the belt is about 30 miles. The width of outcrop ranges from 100 ft. to 1/4 mile or more. Deposits of kyanite-mica schist of very doubtful commercial importance were found in several other counties. Only the deposits of this kyanite-mica schist belt in Habersham and Rabun counties will be discussed in this paper.

Jan 1, 1936

By C. O. Burgess, W. D. Forgeng

DESPITE the increasing interest in and the technical importance of iron-chromium-manganese alloys, very little published information is available regarding their constitution. F. M. Becket's paper1 in 1930 represents the first correlated effort in the field of these alloys. The paper served particularly to draw attention to the commercial possibilities of iron-rich alloys containing chromium and manganese in balanced proportions. The duplex structure of alloys within the commercial range was briefly discussed, but exposition of their structural constitution was necessarily limited because the physical properties and corrosion resistance of the alloys were the main subjects of the paper. Both prior to and following the publication of F. M. Becket's paper, and at his instigation, an extensive investigation of the constitution of iron-chromium-manganese alloys of commercial purity was in progress at the Union Carbide and Carbon Research Laboratories, Inc. The present paper is based on the results of that investigation. In the last few years, investigations covering various portions of this alloy system have also been made in Europe. W. Koester briefly mentioned the effect of annealing on chromium-manganese steel2 and later3 constructed approximate sections of the iron-chromium-manganese equilibrium diagram. M. Schmidt and H. Legat14 even more recently studied this system, and their article and conclusions are of interest as representing an entirely independent study of a number of iron-chromium-manganese alloys. Koester's sections are shown in Fig. 1. The figures summarize the effect of manganese additions to iron alloys containing 5, 10, 15 and 20 per cent Cr as well as the effect of increasing chromium content on iron alloys containing 3, 8, 20 and 30 per cent Mn. These diagrams, within their composition limits, substantiated in some measure the results of our investigation. However, in our work some differences as regards the position of the mixed alpha-gamma fields were found as compared to Koester's work, and we were able to detect the presence of

Jan 1, 1938

By A. E. J. Engel

INDUSTRIAL talcs and ground soapstones both include earth materials of different chemical and mineral compositions. In general, the industrial talcs are composed of silicates that contain appreciable amounts of magnesia. Generally talc, the mineral, is a predominant or at least common constituent. Talc, the mineral, is a hydrous magnesium silicate, with a suggested theoretical formula H2Mg3 (SiO3)4 or H2O.3MgO.4SiO2, which postulates 63.5 pct SiO2, 31.7 pct MgO, and 4.8 pct H20.11 Actually different single grains or leaves of pure talc have variations in water content ranging from 3.5 pct to more than 7 pct, as well as slight differences in the proportions of MgO and Si02.16 Only a very small percentage of the ground industrial talcs produced in the United States approaches the composition given above (see Table 1). The purer talcs invariably occur as alteration products of magnesium carbonate rocks. Some of these relatively pure talcs include compact, massive types largely mined in California, which are designated as steatite.38,58 In general, steatites cannot contain in excess of 1.5 pct CaO, 1.5 pct combined FeO and Fe203, and 4 pct A1203. The less pure varieties of massive talc and mixtures of magnesian silicates are commonly called soapstones, or merely talc. Many industrial earth products classified as talc or as soapstone contain a variety of minerals, especially serpentine (H4Mg,Si2O9), chlorites (hydrous magnesium, iron, aluminum silicates), tremolite (Ca2Mg5H2[SiO3]8), anthophyllite ([MgCa]SiO3), diopside (CaMg[SiO3]2), and quartz (SiO2). The carbonates calcite (CaC03), dolomite (CaMg[CO3]2), and magnesite (MgCO3) are also present in some industrial talcs and soapstones. Some of these minerals, as well as sulphides, sulphates, and iron and manganese oxides, if present at all or in excess of minute amounts, may alter the composition of the industrial talc sufficiently to restrict materially its use or to lower or destroy its value. These factors are discussed in a subsequent section of this chapter.

Jan 1, 1949