Odkrywka

Wychodnia węgla na Alasce, fot. 1891

Odkrywka – w górnictwie przypowierzchniowe złoże surowca, odsłonięte geologiczne, w sposób naturalny (erozja) lub sztuczny (przez człowieka).

Odkrywki stanowiły pierwszy etap w historii rozwoju górnictwa ze względu na bezpośrednią dostępność złoża i uważane są za pierwsze kopalnie naziemne – zwane od sposobu wydobycia kopalniami odkrywkowymi.

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Factory and industrial management (1891) (14597376320).jpg
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Identifier: factoryindustria23newy (find matches)
Title: Factory and industrial management
Year: 1891 (1890s)
Authors:
Subjects: Engineering Factory management Industrial efficiency
Publisher: New York (etc.) McGraw-Hill (etc.)
Contributing Library: Engineering - University of Toronto
Digitizing Sponsor: University of Toronto

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Text Appearing Before Image:
top. The seam is 47 inches thick at outcrop and 53 inches thick at the end of a drift 97 feet long. bors of tlie coal tields of Puget Sound and \ancouver Island areadmirably protected from storms, but the Kyak coal has no naturalharbor, and this is true of many of the Alaskan coal fields. Westward from Kenai, the greatest and most extensive coal fieldin Alaska is reached, cropping out in many different seams, in two har-bors on the Pacific and one on Bering Sea. These Chignik-Unga-Herendeen Bay coal measures, lat. 55° 30 to 56° 30, long. 158° to161°, are not onlv the most extensive and most accessible fields inAlaska with coal in quality next to that of Kyak. but fully equal toany coal mined further south. The specific gravity runs from 1.33 tor.49; the coal is hard, brilliant, clean and very strong, not crumblingunder severe exposures to water, frost, or sun, nor with very roughusage. This field is of unique value because of its location in the key- 174 THE ENGINEERING MAGAZINE.
Text Appearing After Image:
A BERING SEA HILL TOP, COVERED WITH TUNDRA Each man is sitting on an outcropping coal seam. The tundra is broken by mud patches into which one can sink knee-deep. Stone of the North Pacific. Not only does the shortest possible steamerline from the United States or British Columbia to any part of Asiarun within 20 miles of this field, but it is also the nearest of all Ameri-can coal mines to all the island possessions of the United States on thePacific, the nearest part of the American mainland to Hawaii, toSamoa, to Guam, and to the Philippines, and also by nearly 2,000miles nearer than the Puget Sound mines or San Francisco to allparts of Asia, and especially to the great mining regJon recently devel-oped on the shores of Bering Sea. There is a market to-day on theshores of Bering Sea, according to the United States census agent inAlaska for i8qo and 1900, for 80,000 tons of coal at prices from $10 to THE COAL RESOURCES OF THE PACIFIC. 175

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