. The Vermilion iron-bearing district of Minnesota : with an atlas . ? -^ BOTTOM or PIT „?? ! * -^^mmzm^^^^^^^ \\4-TH L^VEL. I 5TH LEVEL eTH LEVEL 80 feet- Fig. 15.—Longitudinal section through Soudan mine. carried by this cribbing tlii-ough the fills on the various levels below. Tothe left is shown a diamond drill, used in drilling holes in the ore fonningthe roof of the stope, into which dynamite is then introduced anddischarged, bringing down enormous masses of the ore. The rock -for this filhng is obtained from the raises which are cut inthe soap rock at the foot or hanging wall, and which
. The Vermilion iron-bearing district of Minnesota : with an atlas . ? -^ BOTTOM or PIT „?? ! * -^^mmzm^^^^^^^ \\4-TH L^VEL. I 5TH LEVEL eTH LEVEL 80 feet- Fig. 15.—Longitudinal section through Soudan mine. carried by this cribbing tlii-ough the fills on the various levels below. Tothe left is shown a diamond drill, used in drilling holes in the ore fonningthe roof of the stope, into which dynamite is then introduced anddischarged, bringing down enormous masses of the ore. The rock -for this filhng is obtained from the raises which are cut inthe soap rock at the foot or hanging wall, and which communicate 238 THE VERMILION IRON-BEARING DISTRICT. from level to level with the bottom of the open pit. Such a raise passesthrough a level with its fi-ont face cribbed and an opening in the raise atthe height at which it is desired to discharge the filling into the tramswaiting for it. When filling is desired at any place the entire raise below that point is filled, and the fillingthen run through the opening in thecribbing at the proper place; or tim-bers and rails may be laid acrossthe raise, making a floor, whi
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectgeology, bookyear1903
