With that blind obedience peculiar to the Orientals, the men immediately knocked away the pillars, when down came the rock, killing half the men in the mine, and among them the stupid superintendent, who had ordered the removal of the supports.
DANGERS IN A COAL SEAM.
There are many dangers and difficulties to be encountered in opening a coal seam. The ordinary mode is to dig away the coal from the lower part of the seam, and allow the substance to fall down in large blocks. To perform this work the miner must lie on his side, frequently in a hot temperature, and in this position he digs away with his tools. It is not unusual for the coal to fall upon him, sometimes injuring him seriously, and sometimes killing him. In his work the miner is frequently stripped to his trousers and shoes, and sometimes he works entirely nude. The perspiration streams from his face and from his entire body, and he is unable to continue his labors for any extended period of time.
Sometimes the coal can be removed by means of tools, without the necessity of blasting, but very often it is necessary to employ the force of gunpowder. The rock is drilled, and then the charge must be placed in the hole. There is always more or less danger of premature ignition of a charge, and in consequence of such ignition, men are frequently killed.
The most dangerous place for blasting operations is in the shaft. The men can only retire after the charge is lighted, and when this is done it is imperatively necessary that they should be drawn up with all speed.
One day, at a mine in Pennsylvania where a shaft was being sunk, the men had lighted the fuse and given the signal to be drawn up. Somehow, just as the bucket was started, some of the machinery gave way, and the men remained at the bottom of the shaft. The fuse was slowly but steadily burning, and there was no time to be lost. One of the men jumped from the bucket and cut off the fuse when it had burned to such a point that another moment would have rendered the explosion inevitable.
A safer way than using the ordinary fuse, is to fire the charges by means of electricity. This method, however, is not always practicable, owing to the expense and the difficulty of employing it in small operations.
Nitro-glycerine, which was invented in 1847, has been found to possess many advantages over gunpowder, and the day is not far distant when it will be used for all blasting operations on an extensive scale.
UNDERGROUND FIRES.
The firing of gunpowder and nitro-glycerine is not the only source of danger which threatens the miners by fire. There is frequently in coal mines a spontaneous combustion, produced by the heating of fragments of coal from the decomposition of iron pyrites in contact with moisture. When the small coal of certain mines is left in heaps within the mines, they speedily undergo this decomposition, especially in a moist atmosphere, which is accompanied by a great development of heat.