CRANE. | Economy of Mining Operations. 341 
ground, 10 to 15 feet per day is considered good progress. 
The actual cost per foot of drilling (labor costs) ranges from 
75 cents to $1. The cost of casing a hole is extra, the owner 
paying for all supplies. 
Tools must be sharpened two to four times a day, usually 
once for every 15 to 25 feet of advance, and occasionally in 
passing through 18 inches of flint. Four hours spent other 
than in drilling is probably a fair estimate. 
Mineé Driviuine.— Drilling for shaft sinking, driving drifts, 
stoping, and in fact all underground work, varies, as does 
prospect drilling, with the kind and character of the forma- 
tion worked, and, if anything, it is more difficult to make es- 
timates upon. 
Very little contract work is done; so there is no fixed price 
per foot of hole drilled or per cubic foot or yard of ore broken 
down. The wages of the single- and double-hand drillers 
are $1.75 to $2.50. The speed of drilling double- and single- 
hand in limestone and flint ranges from 8 to 14 or 16 down to 6 
to 8 or 10 feet per shift of eight hours. The actual cost of 
drilling per foot is then about 20 and 30 cents for single-hand 
and 16 and 25 cents for double-hand work in limestone and 
flint, respectively. 
The tempering of drills will materially affect the speed of 
drilling ; so great care (more than is usually given) should be 
taken in ascertaining the proper temper to be given, and in 
seeing that the drills are kept up to the standard, or varied 
with the character of material drilled. Much time, labor and 
expense is saved by proper tempering, and so preventing the 
too frequent return of the drill to the shop. 
Cost of Shafting and Drifting. 
As the operations of shafting and drifting are so similar, 
the two are discussed under the same head. If there is any 
advantage, one over the other, it is in favor of drifting, for 
the reason that the face of the drift is usually of greater cross- 
section than that of the shaft, and another advantage is that 
it is easier to work a vertical face, as it is to a certain extent 
self-cleaning, gravity actually aiding the blasting operations ; 
while in shafting, gravity not only interferes with the loosen- 
