Contributions to Economic Geology, 1905 (Google eBook)

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U.S. Government Printing Office, 1906 - Mines and mineral resources - 506 pages
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Page 14 - B 293. A reconnaissance of some gold and tin deposits of the southern Appalachians, by LC Graton, with notes on the Dahlonega mines, by W. Lindgren. 1906. 134 pp. ,9 pis.
Page 189 - North. The ores come in competition with foreign ores and the manganese mining industry has steadily declined for a number of years. The more easily accessible deposits are so far exhausted that the production will probably never reach its former proportions.
Page 8 - ... of each quadrangle are issued in the form of a folio. When all the folios are completed, they will constitute a Geologic Atlas of the United States. A folio is designated by the name of the principal town or of a prominent natural feature within the quadrangle. It...
Page 454 - In examining sand in order to ascertain its value for glass making, inspection with a magnifying glass is the best preliminary test. The following points should be observed : The sand should be nearly white in color; it should be of medium fineness (passing a 20 to 50 mesh horizontal sieve) ; the grains should be uniform in size, even, and angular, or...
Page 472 - A deposit so thin as 20 feet should have an areal extent of at least 20 acres of good sand in sight to warrant the erection of a mill and trackage. Most deposits are thicker than 20 feet, but it would be safer to have a much higher ratio between areal extent and thickness than the minimum given.
Page 454 - Sand uniformly liner than one-sixtieth inch is said to "burn out" in the batch and not to produce as much glass per unit of weight as does coarser sand. In a mixture of coarse and fine sand the finer sand is liable to settle to the bottom of the batch, thus preventing an even mixture of the materials and pi inducing in consequence a glass uneven in texture.
Page 473 - ... base of the drier. After one more screening the sand was stored ready for shipment. Glass sand is reported to be produced at Leavittsburg, Trumbull County, about 10 miles northwest of the Austintown quarries. WEST VIRGINIA. The deposits of pure quartz sandstones occurring between Hancock, Md., and Berkeley Springs, W. Va., have been quarried for many years, but it is only within the last years that mining operations have become active. Geology. The sand is derived from a white sandstone composing...
Page 108 - SW. The ore body varies from 10 to 35 feet in width, and is reported to be 430 feet long. The ore carries chalcopyrite, bornite, and chalcocite in disseminated particles in the quartzite. The quartzite is not particularly fissured and does not appear to differ from the rock of the foot and hanging walls. The greater part of the mineralized quartzite contains about 4 per cent of copper, with 6 ounces of silver, and 0.1 ounce of gold per ton. The ore shipped is worth $9 to $10 per ton, the Butte and...
Page 89 - Lindgren says: The quartz forms an almost continuous sheet along the vein, rarely less than 3 feet in thickness and often expanding to a width of 20 feet or more. As a rule, the walls are poorly defined and slickensides indicating motion are rare.
Page 7 - ... included numerous papers relating to the economic geology of Alaska. In view of the rapid increase of economic work both in Alaska and in the States and the organization of a division of Alaskan mineral resources, distinct from the division of geology, it was in 1905 considered advisable to exclude all papers relating to Alaska.

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