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Geological Survey of Michigan; Reports 1869-73-1903-4 (Paperback) Loot Price: R544
Discovery Miles 5 440
Geological Survey of Michigan; Reports 1869-73-1903-4 (Paperback): Michigan. Geological Survey.

Geological Survey of Michigan; Reports 1869-73-1903-4 (Paperback)

Michigan. Geological Survey.

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Loot Price R544 Discovery Miles 5 440

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1873 Excerpt: ...powder. One inch octagon steel is often used in this work, making a hole nearly 1% inches in diameter. The drilling is performed as in the case of stope-holes, but usually only one man strikes. In the same ground, the same drill-gang will sink more than twice the number of feet of block-hole in a day with small steel, than of stope-hole with large steel, --ranging from twenty-four to twenty-seven feet. In open mines of strictly hard ore, this work costs more than stope-holes, and is set down in the table at I3 cents per ton. This amount added to the II cents given as the cost of stope-holes per ton, equals 24 cents for the total cost of the labor ofrirz'1/ing required under breaking ore: --this would also equal about 70 cents per cubic yard, which would pay for one foot of two-inch drill-hole. But this is by no means the whole; the work of sinking and drifting, which is set down as aggregating 20 cents, is more than half drilling; and a part of the cost of rock-stripping is also for this work. I estimate that 40 cents per ton of ore is not far from the actual price paid for this kind of labor in the hard-ore mines, equal to fifteen per cent. of the whole cost. On this estimate, not less than $300,000 were paid out for drilling in I870. This work, from the favorable circumstances under which much of it is done in open excavations, no scaffolding being required, is by far the most purely mechanical labor performed about the mines. While the absolute cost of this item of drilling is very large, and can undoubtedly be reduced by the use of thepower-drill, it is, as compared with some other mines and regions, small. Our open cuts or quarries afford far better facilities for blasting than under-ground mines. In one Southern New York mine the drilling cost, in 1870, ...


Imprint: Rarebooksclub.com
Country of origin: United States
Release date: May 2012
First published: May 2012
Authors: Michigan. Geological Survey.
Dimensions: 246 x 189 x 11mm (L x W x T)
Format: Paperback - Trade
Pages: 196
ISBN-13: 978-1-236-27350-5
Categories: Books
LSN: 1-236-27350-8
Barcode: 9781236273505

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