336 GEOLOGY OF OHIO. 
Two miners work together in rooms and entries; they keep each 
other company, assist in setting props; one watches while the other 
works in dangerous situations, and if one is caught, the other can raise 
the alarm and call in adjoining comrades to the rescue. 
The first and the most laborious part of the work of coal digging 
consists in undermining, or bearing in, or holing the rooms. This is 
generally performed in the bottom of the coal seam with the pick. An 
undermining is made of varying depth, sometimes 3 to 4 feet, frequently 
5 or 6 feet; the miner stands upon his feet, and strikes with all his 
strength, until a few inches in depth are bored in; he then sits down on 
the floor of the mine, his legs stretched wide apart in front of his body, 
and cuts in 6 inches to a foot deeper; finally he stretches his body along 
the floor, his shoulder and arm to the elbow resting upon his thigh, and 
in this constrained position finishes up the undermining. It will take 
two active miners 4 or 5 hours to undermine a room 8 yards wide and 
4 to 5 feet in depth. forty to fifty blows of the pick are delivered per 
minute, and considerable skill is exercised in holing. Miners raised to 
the work from boyhood are both speedier and cleaner workmen than 
those who assume the calling after manhood. There is a good deal of 
difference also in the nature of the undermining, some beds cutting 
easy, others hard. A room is not usually undercut across its whole 
breadth in preparing a blast, though it is better to so undercut it. 
Having finished the undermining, the next thing in order is boring 
a hole for the blast. Some skill is also required in performing this 
work, so as to give the powder the best possible advantage. In some 
mines more reliance is placed upon the drill than upon the pick, the 
coal being largely blasted out of the solid. In doing so the miner 
shatters the coal, but this gives him little concern so long as it 
adds ease to his body. Coal is not mined now with the care and skill 
of 10 and 12 years ago. The amount of powder required for a shot 
varies from 1 to 8 pounds, the former amount sufficing when the coal is 
properly undermined—the latter amount being required in blasting out 
of the solid. Asa general rule, a pound of powder is burned for every 
3 tons of coal mined. . In the Massillon region, where the main weapon 
of the miner is the drill, a pound of powder is burned for every single 
ton mined. In some mines powder is not required, the coal being 
knocked down, after it is undermined, with wedge and sledge. 
The entries of mines are driven so narrow that prop-wood is not 
