“The gangway—yes. And since the only open break-through between them is away at the other end of the mine?”
“The fresh air must go clear through the mine before it can start out again.”
“That’s it—that’s it exactly!” and Lambert slapped his thigh with pleasure at her quickness. “That’s the whole secret, Miss Bessie, of ventilating coal-mines: get your fresh air, and plenty of it, clear back to the end, through every chamber, before it starts out again. So long as you do that, there’s mighty little danger from fire-damp and choke-damp, or any of the other gases the coal is always throwing off.”
“But it isn’t always so simple as this, is it?”
“No. You see, there are three ways of opening a coal-mine, Miss Bessie, of which this is the very simplest. The river, there, has cut down through the seams of coal and left them exposed, so all we have to do is to hunt up those most favorably located and work right back into them. That sort of entrance is called a drift, and is the cheapest as well as simplest, because every blow of the pick brings down so much coal. That’s the great advantage of all the mines along this river—along almost any river, for that matter. Sometimes the seams don’t come to the surface, and then we have to tunnel in horizontally through earth and rock to reach them; that’s the second way. The third way is where the coal is buried deep in the earth, and a vertical opening called a shaft has to be sunk to it, and the gangways started out horizontally from the shaft-foot. That is the most expensive way of all, and the most difficult. This main entrance is called the gangway or entry, and the side workings from it are called butt entries. Well, let’s go in.”
Just inside the entrance a boy supplied them with little smoking tin lamps with hooks to hold them to their hats, and then the trip into the mine began. The darkness that fell upon them almost instantly appalled the girl for a moment. She felt that every step forward must carry her down into a bottomless abyss. She clutched nervously at her companions; but the feeling passed, and soon she was able to advance with greater confidence. The gangway seemed quite level, though Lambert told her it sloped upward slightly so as to throw out all the water that gathered in the mine, and along either side of it ran a narrow wooden track. On one track the loaded cars were brought out of the mine, and on the other the empty cars were taken back again. Mules furnished the motive power, and each of them was driven by a grimy boy. The sight of them going ceaselessly back and forth aroused the old bitterness in her.
“I think it is such a terrible thing,” she said, “that children have to work in the mines!”
“It’s not pleasant,” assented her guide, grimly, “but it’s a case of bread and butter—and mighty little butter. They’re not in any danger, though,” he added, “except from being kicked or bitten by the mules. Some of them are vicious brutes, but the boys soon learn how to handle ’em.”
The rattle of an approaching “trip” of cars drowned his voice, and they stepped aside to let it pass. For a moment they could see nothing; then the mule flashed into view, with a boy lying flat on its back to escape the roof, the flame of his lamp streaming thinly out behind; then four loaded cars, rocking and swaying on the narrow track.
“You see, the slope of the gangway helps get the loaded cars to daylight,” observed Lambert, “as well as throw out the water—and there’s lots of water in a mine.”