Contributions to Economic Geology, 1904

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U.S. Government Printing Office, 1905 - Geology, Economic - 620 pages
 

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Page 497 - ... of the clayey materials. The burning takes place at a high temperature, approaching 3,000 F., and must therefore be carried on in kilns of special design and lining. During the burning, combination of the lime with silica, alumina, and iron oxide takes place. The product of the burning is a semifused mass called clinker, and consists of silicates, aluminates, and ferrites of lime in certain definite proportions.
Page 501 - Isilica, alumina, and iron oxide) of the Rosendale rock could be removed, leaving only the magnesium and lime carbonates, the burnt rock would lose all of its hydraulic properties and would yield simply a magnesian lime. This point has been emphasized because many writers on the subject have either explicitly stated or implied that it is the...
Page 304 - The Chicago and Northwestern, the Chicago, Milwaukee, and St. Paul, and the Chicago, Indiana, and Southern railroads also enter the area.
Page 497 - Portland cement is produced by burning a finely ground artificial mixture containing essentially lime, silica, alumina, and iron oxide in certain definite proportions. Usually this combination is made by mixing limestone or marl with clay or shale, in which case the mixture should contain about three parts of the lime carbonate to one part of the clayey materials.
Page 500 - Portlandcement mixture could be prepared by combining, in an almost indefinite number of ways and proportions, many possible raw materials. Obviously, too, we might expect to find perfect gradations in the artificialness of the mixture, varying from the one extreme where a natural rock of absolutely correct composition was used, to the other extreme where two or more materials, in nearly equal amounts, are required to make a mixture of correct composition.
Page 159 - The gold and silver veins of Silver City, De Lamar, and other mining districts in Idaho. In Twentieth Ann.
Page 493 - The geology of the road-building stones of Massachusetts, with some consideration of similar materials from other parts of the United States.
Page 500 - ... under existing commercial conditions. The necessity for making the mixture as cheaply as possible rules out of consideration a large number of materials which would be considered available if chemical composition was the only thing to be taken into account. Some materials otherwise suitable are too scarce; some are too difficult to pulverize. In consequence, a comparatively few combinations of raw materials are actually used in practice. In certain localities deposits of argillaceous (clayey)...
Page 542 - ... from railroads that, in spite of the excellent rock shown at a few places, exploitation of this region is at present useless. Furthermore, throughout a considerable portion of this region the argillaceous limestones are cut out by overthrust faulting, the magnesian limestone resting upon the shales or still higher formations. But a single area can be mentioned in which the cement rocks are exposed within a reasonable distance of a railroad. Several miles north of Stokesville, the terminus of...
Page 315 - Dodgeville the fact should be remembered that in the greater part of the Wisconsin lead and zinc district the more valuable lead and zinc deposits have occurred above this horizon, and there is no reason to suppose that such deposits may not exist in the less eroded portions of the Dodgeville area. Considerable work has been done in the past on lead-bearing crevices at these higher elevations, and one company has recently started development work on one of these old lead ranges. Mention should also...

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