Davies, Charles, 1798-1876 · New York, Cincinnati [etc.] American book company · leaf 376
arefulengineer will not incur the expense of sinking a deep working shaftto intersect an inclined vein, until he has followed the vein forsuch a distance that the possibility of its terminating, or pinch-ing out, is quite remote. Should the vein be irregular and notpossess well-defined fissure… … Fig. 196. 370 ELEMENTS OF SUEVEYIJ^G. [BOOK X. of the vein. If, on the other hand, the vein is found to be strongand regular, possessing well-defined fissure characteristics to adepth of 150 to 250 feet, the working vertical shaft might besunk with comparative safety. No rule can be laid down,…
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