Engineering and Contracting . to 1 in solid ledge, but leaving ahorizontal berm of 10 ft. width on the sur-face of the ledge. These plotted sections in-dicated to contractors, just where to expectthe ledge and shovel cuts were arranged ac-cordingly. .\fter the rock was stripped inany cut of the shovel, drills were started andin the following rut, shooting was done im- posed at that end first oermitting the westdrifts to start there in March of 1911, whileat the east portal, the drifts could not bestarted until July of the same year. This re-sulted in about two-thirds of the tunnel be-ing drive
Engineering and Contracting . to 1 in solid ledge, but leaving ahorizontal berm of 10 ft. width on the sur-face of the ledge. These plotted sections in-dicated to contractors, just where to expectthe ledge and shovel cuts were arranged ac-cordingly. .\fter the rock was stripped inany cut of the shovel, drills were started andin the following rut, shooting was done im- posed at that end first oermitting the westdrifts to start there in March of 1911, whileat the east portal, the drifts could not bestarted until July of the same year. This re-sulted in about two-thirds of the tunnel be-ing driven from the west end. In Fig. 4, thelocation and comparative size of drifts, head-ing and bench are shown. The drifts desig-nated A, were about 7 ft. wide at the bottomwhich was on a level with the under side ofthe wall plates, but narrowing at the top inthe form of a Gothic arch. Ordinarily threedrill holes were used in positions as indicatedand inclined slightly outward from the cen-ter. These were 2-in. holes about 4 ft. in. ?2400 -;295- ZOW ?i^^ MeosunngSoK .\ ,stpne Slide iGuJ/Dernch: Mixer .\.^; Sand Slide .ei;* J tBlachsmit^iShop.\ rtS^k^CemenfHouse D< Moiglmg-ptfgoe JU -^y/ff^Cement Slide V^ater ,, . -., y ^-.~-£6ciife-Khoth Dynamite. NorthTrochjyr^:.- -j^ ^T. r~Jo/ ynamite .Ah^rpip^une m- Heating ; ^tacfJ^rnnf^-S^^~^°^e--- TempororiEndofrra%rU~: Bottom Of Slqpe-:^ r\o^ = ?^^-^^-^^^^ , to; Spoil ?Bottom of Slope Frarning C S^t^ W flY DootileTracli^ of Slope Platform Lqyv N GTr Tunnel. ?T^ • Temporary Dicf ~-~~\ much ,\ ofTraclK frnmWest HonM Camp No B
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherchicago, bookyear19
