186 University Geological Survey of Kansas. 
feet in the clear. When this square or rectangular opening 
has been sunk to the ore, it is hollowed into a basin 5 to 10 
feet deep, which forms a temporary ‘‘sump,”’ acting as a re- 
ceptacle for the surplus waters of the mine. The ore hav- 
ing been reached, and the sump formed, an opening is cut 
into the side of the shaft. This opening, or heading, is the 
beginning of a drift, and is generally high and wide enough 
for two men to work in, side by side, with ease. Nothing 
but the direction which the lead of the ore takes governs the 
cutting of the drift horizontally. It is, however, always run 
on an approximate level. If at any point in the advancing 
of the drift the ore body is found to widen out, the horizontal 
dimensions of the drift may increase from one hundred to two 
hundred feet. In most cases, however, portions of the ore 
or rock mass are left as supports or pillars, which, if the 
former, are generally removed before abandoning the mine. 
If the ore body thickens or extends upward, the roof will be 
stoped down, or as is generally the case, due to the method 
of development employed, the bulk of the ore lies below the 
exploring drift, the floor is stoped up. 
In the former case, the ore is removed by ‘‘overhand 
stoping,’’ while in the latter case by ‘‘underhand stoping.”’ 
As little or no separation of the barren rock.from the ore is 
attempted underground, the complete extraction of the ore 
being the object, the latter of the two methods above men- 
tioned is the most applicable. 
Drifts are started from the shaft, as soon as an indication 
of ore is found, so as to strike the upper part of the ore 
body. If successful, the operation of underhand stoping be- 
gins. ‘The drift is first driven for quite a distance in the ore 
body, or through it; at the same time it is widened out, 
both for the purpose of removing the ore and to deter- 
mine the extent of the deposits. It is, therefore, evident 
that the process of stoping increases the vertical dimensions 
of the workings even to a hundred feet or more, while ad- 
vancing the breast increases the horizontal dimensions, to 
which operation there is no limit, if proper supports or pil- 
lars, natural or artificial, are provided. If no supports are 
furnished, the rooms seldom exceed a breadth of fifty or 
