Synopsis
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. 1907 edition. Excerpt: ...reasons no longer to be taken into consideration, as will subsequently be explained. 15. Reliability of the Boring Process.--It will be seen that very strenuous work is being done in this branch of mining, and that the manifold difficulties which are encountered at every shaft sinking in other and new form are always overcome with success. It can be seen from the accompanying list of borings which have been made by the Kind-Chaudron method of shaft sinking, not only that the process is very frequently employed, but also, in spite of the greatest technical difficulties, it has never failed. It must, however, be mentioned that the process is almost without exception employed only as a last resource, when all other possible methods have been tried without result. For this reason only small portions of these shafts have been sunk by the boring method, and in each case those parts of the shaft in which very serious difficulties were encountered. This circumstance explains that the charges made against the process from time to time of slowness and high cost are not based upon a fair comparison with other methods. A process, which even under the most difficult conditions has always given a definite result, can in no manner be compared intelligently with the methods which have failed with a similar problem. It would be like comparing the sinking of two shafts by hand and concealing the fact that one was perfectly dry and the other had to be sunk when water amounting to 2200 gallons per minute had to be contended with. In many cases, if it was known beforehand that a portion of the shaft must be bored, an advantage would be gained if boring was started before the difficulties of hand sinking with the aid of water-lifting appliances had become...
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