CRANE. | Developing Mineral Properties. 199 
subsequent shock, as a blast or fall of ore, can cause it to give 
way, but with the ordinary height of drift that is unnecessary. 
The roofs are carefully arched and dressed by brushing, 
which is accomplished by putting in light charges in holes 
slanting forward. The roof is then thoroughly tested by 
prod poles furnished with steel points, and if it does not give 
out the peculiar sharp ring of solid flint, it is worked with, 
even to the putting in of other shots, until all unsafe portions 
are removed. From time to time this process is repeated to 
insure perfect safety. 
The numerous accidents that have occurred during the last 
few years seem to indicate a growing carelessness in the 
supervision of mines by the responsible parties in charge. 
Methods of Stoping. 
Drifting is largely a means of discovering ore bodies. Sto- 
ping is the operation employed in working the ore when found. 
When the ore lies in the floor of the drift, that is, when the 
drift passes through the upper portion of the ore body, under- 
hand stoping may be employed. The floor and face of the 
drift then contain the material to be removed, which can be 
easily won by the ordinary methods of breast and under- 
hand stoping. 
Underhand stoping is really a process of lifting or remov- 
ing the floor of the drift which contains the ore, figure 10, 
and consists in starting with the shaft and working along the 
floor of the drift. The stopes generally run from 7 to 10 and 
12 feet in depth. The shaft, being the starting point of the 
stoping operation, very naturally has to be sunk 10 to 12 feet 
deeper, and a sump formed. With the beginning of each 
new stope, the floor of the drift is taken up to the bottom of 
the shaft or the top of the new sump formed, and continued 
at that level until the end of the original drift is reached, or 
the ore body is passed through by its terminating or extend- 
ing into the lower level. If the ore body continues to pass 
downward, the floor of the drift is restoped, and this process 
is continued until the ore body is exhausted. 
It is therefore evident that the successive operations of 
stoping increase the height of the worked-out portions of the 
