 | 1834 - 536 Seiten
...two other perpendicular shafts, to meet them, from these the ores and materials may also be raised. By thus sinking perpendicular shafts a hundred yards from each other, the first level or gallery may be carried to any extent. While this horizontal work is going on, the original,... | |
 | John R. Leifchild - 1855 - 340 Seiten
...them, and from these the ores and materials may also be raised. It is evident that by thus sinking shafts a hundred yards from each other, the first...prolonged ad libitum. •But while this horizontal work is going on, the original or engine shaft is sunk deeper ; and at a second depth of sixty feet, a second... | |
 | Sir Francis Bond Head - 1857 - 384 Seiten
...two other sets of miners have been sinking from the surface two other perpendicular shafts, to meet them; from these the ores and materials may also be...prolonged ad libitum. But while this horizontal work is carrying on, the original, or, as it is termed, the engine-shaft, is sunk deeper; and at a second... | |
 | John Murray (publishers.) - 1879 - 290 Seiten
...two other sets of miners have been sinking from the surface two other perpendicular shafts, to meet them ; from these the ores and materials may also...evident that, by thus sinking perpendicular shafts 100 yards from each other, the first gallery, or level, may be prolonged ad libitum. But while this... | |
 | John Murray (Firm) - 1882 - 298 Seiten
...two other sets of miners have been sinking from the surface two other perpendicular shafts, to meet them ; from these the ores and materials may also...evident that, by thus sinking perpendicular shafts 100 yards from each other, the first gallery, or level, may be prolonged ad libitum. But while this... | |
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them; from these the ores and materials may also be raised; and it is evident that, by thus sinking perpendicular shafts a hundred yards from each other, the first gallery, or level, may be prolonged ad libitum. But while this horizontal work 