. A dictionary of arts, manufactures and mines : containing a clear exposition of their principles and practice. The exploration of the upper stories e f, e2 f2, e3 f3, is now prepared in a similarmanner; with which view shafts h hi, k k3, are formed from below upwards in the wallTO of the deposite, and from these shafts oblong galleries proceed, established successivelyon a level with the stories thus iai«ed over one another. See Jig. 730. The followingobjects may be specified in the figures :—. a a, the first cuts filled up with rubbish, upon the first story e F,fig. b, other cuts subs
. A dictionary of arts, manufactures and mines : containing a clear exposition of their principles and practice. The exploration of the upper stories e f, e2 f2, e3 f3, is now prepared in a similarmanner; with which view shafts h hi, k k3, are formed from below upwards in the wallTO of the deposite, and from these shafts oblong galleries proceed, established successivelyon a level with the stories thus iai«ed over one another. See Jig. 730. The followingobjects may be specified in the figures :—. a a, the first cuts filled up with rubbish, upon the first story e F,fig. b, other cuts subsequently filled up, upon the same story. c, the cut actually working. d, the front of the cut, or place of actual excavation of the mineral deposite. e, masses of the barren rock, reserved in the cutting, as pillars of safety. /, galleries, by means of which the workmen may turn round the mass e, in order toform, in the roof/, an excavation in the direction of the deposite. g, rubbish behind the mass e. k k, two shafts leading from the first story e f, to the upper stories of the workings, asalready stated. m, the wall, and t the roof of the mineral bed. In the second story e f, the gallery of prolongation F,^g:s. 728 and 730, is not entirelyperforated; but it is further advanced than that of the third story, which, in its turn, ismore than the gallery of the fourth. From this arrangement there is produced upon fig. 730 the general aspect of a workingby reversed steps. Whenever the workin
Size: 3215px × 778px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1840, booksubje, booksubjecttechnology
