CRANE. | Developing Mineral Properties. 191 
tion for a shaft. The latter theory has been strengthened by 
some phenomenal finds. 
Whether a shaft is to be used for prospecting purposes or as 
a permanent affair the method of sinking is the same. 
Formerly the shafts were made considerably smaller than 
at the present time and were square, only enough room being 
given to allow the passage of the bucket. Most of these 
shafts did not reach a depth of more than fifty or sixty feet 
below the surface and did not enter the lower levels into 
which most of the shafts of to-day pass and in which more or 
less water is found. With the occurrence of water in large 
quantities, the problem of ‘‘ beating’’ or keeping it below the 
mine level could only be solved by the introduction of pumps. 
The lifting of water by buckets is rather an inefficient and 
uneconomical method ; thus the size of the shaft was of neces- 
sity increased in one dimension, at least, to permit the work- 
ing of both pump and.ore bucket in the same shaft. 
Some of the older shafts, still to be found in the district, 
are as small as three and one-half feet square, but most in 
use at the present time vary from 4x5 up to 5x7 and 8 feet. 
The introduction of cages will come with deeper mining and 
they are in fact employed in several of the more modern 
plants. 
Shafts are sunk in the softer material, as dirt, sand, gravel, 
etc., by the use of pick and shovel. The harder materials 
are loosened by powder. ‘Thecharges are usually placed ac- 
cording to the American center cut system, especially where 
steam or compressed air drills are employed. When hand 
drilling is employed, the natural cleavage, fissures and bed- 
ding planes, where they occur, of the rock mass can be taken 
advantage of, modifying somewhat the center cut system. 
As will be explained in detail under drifting, stoping, and 
the exploitation of a mine, rock must be ‘‘free’’ or unbound 
to be blasted easily ; otherwise considerable of the force of the 
explosive will be uselessly expended. The arrangement of 
the shot must be such as to, first, loosen as much rock as 
possible ; and second, to unbind or free that part which re- 
mains, in order that the shaft may be squared up tothe proper 
dimensions with little further use of powder, pick, and bar. 
