COAL MINING. f 327 
from market must have superior coals, which command extra 
prices, or else the trade languishes. The business largely turns on 
the character of the individual seams. The quality of the coal rather 
than its thickness, and the cost of placing the same upon the market, 
very largely determines the value of mining properties and mines. 
All seams of coal, two feet thick and upward, are regarded as of 
mineable thickness, but four feet is regarded as the standard height. 
The expense attending the working of a three-feet vein is often con- 
siderably greater than working one four feet, exclusive of the dead 
work. This is a general but not universal rule, and obtains in mines 
like those of the Mahoning.and Tuscarawas Valleys, where the coal 
varies suddenly in thickness. In such mines, for digging all coal below 
four feet, 5 cents per ton extra is paid for every 3 inches of decreasing 
height, until the seam falls to two feet, when it is regarded as unmine- 
able. At Leetonia, Hammondsville, and in the Coalton district of 
Jackson county, coals no thicker than 28 to 32 inches are wrought, but 
these coals possess peculiar qualities. The best coke in the State is 
made at Leetonia and Hammondsville, and everything that comes from 
the miner’s pick is credited to him. At Coalton the coal is tender, and 
mines very easily. The difference in expense of mining a 4-feet coal 
over a seam 10 feet in thickness is inconsiderable in amount; the ad- 
vantages to mining operators who possess thick coals consisting more 
in the greater yield per acre than the lessened cost of production. Thus, ' 
at Wellston, in Jackson county, the coal is 4 feet thick ; while at Straits- 
ville the bed is 9 to 10 feet thick, but the same price obtains in both 
places for digging; at Wellston the coal is a homogeneous mass, while. 
the thick coal of the Hocking Valley contains two bands of shale, and 
frequently a band of bone coal, which have to be sorted out by the 
miner, which militates considerably against his producing power. 
In point of economy, drift mines do not ordinarily possess any 
material advantage over shaft mines opened in the same district. 
Tt costs less, it is true, to open and equip a drift than a shaft; but 
after a shaft is opened and equipped the workings may be extended east, 
west, north and south, without any interruption to their symmetry or 
continuity. In drift mines on the other hand, even under the most 
favorable circumstances, not more than one-half of the same extent of 
work can be opened up; and, frequently, by means of the numerous 
avines which cut down through the coal, a symmetrical and extended 
ip 
