CRANE. | Developing Mineral Properties. 197 
the larger the timbers, the deeper the notch. Some timbers 
are notched on both sides; others only on one side. When 
two-by-fours are used they are not notched, but lapped, and 
the intervening space filled in with shorter pieces, forming 
closed cribbing. 
Cribbing is always built from the bottom up, in sections. 
A shaft is usually sunk, in hard ground, 80 or 100 feet before 
cribbing is begun, but if the ground is soft, after it has 
reached a depth of 20 or 30 feet it is cribbed up to the start- 
ing point, or to the bottom of the section above, if other sec- 
tions have been placed. Iron hangers (a, fig. 25), or dogs, 
are used to mark off the length of the section and to support 
the foundation frame to be built upon. They consist of flat 
iron bars, eight or ten feet long, with the two ends turned in 
the same direction, and at right angles with the bar. One 
end is hung on the lower end, or frame, of the cribbing 
above. The cribbing to be built is constructed upon a frame 
(foundation frame) which rests upon the hooks at the lower 
end of the bars. The length of the hangers is such that the 
timbering or cribbing when completed fits in perfectly, and 
when fastened to the cribbing above makes a permanent con- 
tinuation of the same without any adjustment. The hangers 
can be removed and the operation repeated as the shaft in- 
creases in depth. 
- When a pump is to be introduced into a shaft, the dimen- 
sions are generally 6x8 feet in the rough and 5x7 in the 
clear, finished shaft, making a 4)x5-foot hoisting shaft and a 
2x5-foot pump compartment. In many cases the pump is 
placed in the corner of a shaft 4x5 feet in the clear. This 
crowds the shaft and necessitates the stopping of the hoist- 
ing when any repairs have to be made on the pump or col- 
umn pipes. 
Methods of Drifting. 
In prospecting, the shafts are sunk until a ‘‘shine’’ (an 
indication of ore) is struck ; then, if the indications are promis- 
ing enough, a drift is started; that is, a passage is begun 
in the side of the shaft. The drift is generally 6x8, 8x8, 
or 8x10 feet, sufficiently large for two men to work in side 
by side. A face of this size is carried so that the extent 
