COAL MINING. 329 
the mouth of the opening ; experienced miners take up several feet of 
the bottom, which they tail out to a point. 
It is not always practicable to open and work to the rise of the 
strata. The main entries of many mines run east or south. This 
always adds to the cost of getting the coal, but it cannot be avoided. 
When the coal lies in the hill, 25 to 30 feet above the level of the 
railroad switch, the most favorable conditions for opening a mine are 
found, as this gives the proper height for dumping the mine cars through 
the chutes into the railroad cars below. We have, however, to accept 
the conditions as we find them; and frequently a mine is opened high 
upon the hill. Under such circumstances an inclined plane is con- 
structed from the chutes to the drift mouth; the track of the plane is 
made double, the empty train ascending as the loaded train descends. 
If, in opening a mine, the coal should be found too near the base 
of the hill to admit of dumping height, it adds considerably to the cost 
of hauling, as well as militates against the producing power of the mine 
to pull the loaded cars up-hill, from the mine mouth to the tipple, by 
horse-power ; under such circumstances it is cheaper in the end to pro- 
vide steam-power. 
When a coal bed lies below water level, and has to be sunk for, it 
may be reached by a slope or a shaft. A slope dips at from 25 to 30 
degrees, and is preferred by many managers to a shaft, owing to the 
facility it affords for the ingress and egress of the miners. The ex- 
pense of sinking and equipping a mine with adequate machinery is 
about the same in a shaft or slope until the latter exceeds 150 yards in 
length, when, in point of economy, the advantage is on the side of the 
shaft. In the Mahoning and Tuscarawas valleys the mines opened on 
the lower bed of the series are generally slope openings. In all 
the other districts of the State the shaft seems to find favor. 
The width of a slope is usually about 10 feet, and the height 53 to 
6 feet. The hauling road or railway track is made single; a loaded 
train of cars, two or four in number, being first hoisted and then an 
empty trip lowered. Shafts are made with double hoists, a loaded car 
ascending in one cage while an empty car descends in the opposite cage. 
Shafts are rectangnlar in shape and are usually 8 feet wide and 16 feet 
long. 
In commencing to sink, whether jby shaft or slope, the horse and 
gin are employed until solid ground is reached. If the opening be no 
