In such cases walls of clay are built up to shut off the fire. When these are constructed perfectly tight, and the atmosphere is carefully excluded, the fire goes out; but for some time the temperature in these parts of the mine will be very great, and the miners find much difficulty in working there. The work of building up the walls in such a case is very serious. The walls become very hot, and men are frequently rendered insensible. Sometimes carbonic acid gas has been used to extinguish fires created in this way. The portable apparatus known as the Fire Extinguisher has frequently been found very useful.
Sometimes, however, it is impossible to extinguish these fires; and in such cases the place is abandoned. In this country, and in England and Scotland, there are mines now burning which have been on fire for several, and some of them for many, years. One mine in Scotland took fire nearly forty years ago, and is still burning. The ground is black, baked, and scorched. The trees, and grass, and all kinds of vegetation have died, and there is a general appearance of sterility throughout the region.
EFFECT OF UNDERGROUND FIRES.
In several instances, where a fire cannot be extinguished by closing the mines, it has been found useful to flood the works. In France, about twenty years ago, an entire river was turned into a burning mine, and allowed to flow through it for nearly three months. A mine in Pennsylvania took fire, and was filled with water, remaining so filled for nearly half a year before the fire went out.
At Brulé, St. Etienne, there is a coal mine which has been on fire nearly two hundred years. Hot vapors are constantly arising; sulphur, alum, and other natural productions are deposited, and one might suppose that it was the burning of the accursed cities formerly consumed by the fires of heaven and earth. An irreverent American, who visited this region, said that it looked like hell with the fires going out.
In the western part of England there was formerly a coal mine on fire. Snow melted as soon as it touched the ground. The gardens were very beautiful and fertile, and produced three crops in a year. Many hot-house plants were cultivated, and an eternal spring prevailed. It was the same principle, on a grand scale, by which plants are grown in hot-houses by running pipes of hot water through the ground. The people of this region imported tropical plants at a heavy cost, and cultivated them in the open air; but one day the fire went out; the place gradually resumed its usual temperature, and the tropical plants died.
EXPLOSIONS OF FIRE-DAMP.
In many coal mines there is great danger from what the miners call “fire-damp”—an inflammable gas produced from the coal. It is identical with the streams of natural gas, which burn readily, and not unlike the coal gas artificially produced in cities. Certain kinds of coal throw off this fire-damp in considerable quantities. The gas is a combination of hydrogen and carbon. Sometimes its presence is not noticed until an explosion, but in such cases the explosions are not very dangerous. Those who have been accustomed to this explosive material have received a vivid experience of underground life. No meteor, however terrible it may be supposed to be, can be compared to an explosion of fire-damp. A thunderbolt, a hurricane, a typhoon, a cyclone, or a whirlwind, is not more terrible in its effects than a fire-damp explosion. Imagine a discharge of a hundred cannon loaded with canister shot, the simultaneous explosion of a number of powder magazines, or the bursting of the boilers of a steam engine, and the effect will not be more terrible than an explosion of fire-damp in a coal mine.
