287 resultados para Engineering geology.


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The accelerated post-war demand for petroleum products with resultant high prices and dwindling reserves has spurred producers to an extensive search for new fields and for ad­ditional production in known fields. Exploration and discov­ery is dependent on the collection and correlation of vast amounts of data both in the field and that found in liter­ature.

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The United States, although the leading consumer of chromite, depends almost entirely on imports for its supply. Domestic production of chromite is limited, because high-grade imported ore is plentiful and inexpensive in normal times. There are several large deposits of chromite in the United States, representing millions of tons of low grade ore. These deposits form a strategic reserve that must be used in time of national emergency.

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This investigation concerns the development of a satis­factory method or extracting or concentrating gold and silver from the ores of the U. S. Grant Mine. The choice between applying an extractive process and one by which the valuable mineral constituents are concentrated depends on more than one factor.

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At present copper sulfide ores are recovered by pyrometallurgical processes. While the recovery of cop­per from sulfide ores by hydrometallurgical means has long been considered attractive, the impurities, low re­covery and mechanical difficulties have kept this process from becoming commercial.

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The possible benefits of oxygen enriched atmosphere roasting have been known to metallurgists for many years, but only since the development of equipment and processes to produce cheap oxygen in very large amounts has much ser­ious consideration been given this matter.

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Karst Kamp, a southwestern Montana recreation re­sort, is 32 road miles south of Bozeman on the east bank of the Gallatin River in a narrow V-shaped valley flanked on the west by the rugged Madison mountain range and on the east by the equally rough Gallatin range. The asbestos deposit itself lies approximate­ly one-half mile northwest of the ranch on a heavily timbered "Al­pine-like" slope nearly 1200 feet above the floor of the valley.

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The object of casehardening is to produce articles of steel having a tough or ductile interior and a hard sur­face. Quenching produces a surface somewhat harder than the interior, but in order to obtain a high surface hard­ness, the percentage of alloying elements in the steel must be raised to such an extent that the core or central por­tion becomes hard and brittle also.

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The term diffusion means an equalization or homogenization of diverse materials. Specifically ap­plied to metals, diffusion is the interchange of atoms. It is, in effect, an invasion of one crystal lattice by the atoms of one or more other crystal lattices. Therefore, the study of diffusion must involve the geometry and physics of crystal lattices as well as their energies.

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Although there are many uses for manganese today, none of them approaches its importance as a deoxidizing agent in the manufac­ture of steels. Without manganese the steelmaking in­dustry would be very seriously handicapped. The metal­lurgy of manganese has been developed around the high-grade ores, and unfortunately, our reserves of high-grade ores are very limited.

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Imports of manganese ore probably supply a major proportion of the needs of the United States. Domestic production is reported to be higher than pre-war levels, but does not equal that of the peak production year of 1943. In 1946, the Anaconda Copper Mining Company ac­counted for 90 percent of the total shipments of mangan­ese nodules, and this company is the largest producer of domestic metallurgical ore in the United States.

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The manganese minerals occur in the peripheral zone of the Butte district with quartz in veins, which at depth contain galena and sphalerite closely associated with silver-bearing minerals. The manganese oxides are all oxidation products formed by weathering of primary rhodochrosite or rhodonite.

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The Fort Union formation is one of the most import­ant and best known geologic formations of the northern Great Plains, and is found lying almost horizontal at the surface over large areas in this region.

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The minerals sillimanite, kyanite, andalusite, dumortierite, and topaz comprise a group of minerals whose high alumina content and physical properties are particularly desirable in the manufacture of refractory products. Sillimanite is the least plentiful of the minerals of this group, and for this reason it is not used extensively at the present time. However, it would be very desirable to the refractory industry if a suitable domestic source of supply could be established.

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The mechanics of intrusion and the processes involved are becoming of more and more interest to con­temporary geologists, because most of our mineral deposits are associated with igneous intrusions, and unknown-outcropping deposits are thought to be a thing of the past. If, by studying these pro­cesses, we could understand why some igneous masses are barren, while others of similar composition carry economic mineral deposits, geological prospecting for hidden mineral concentration would see a new era.

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Electrolytic silver refining was not perfected until the end of the nineteenth century. During the process of development, two systems of silver refining have come into prominence: the Moebius and the Thum types.