The Underground World: A mirror of life below the surface

by Thomas Wallace Knox

ACCIDENT AT CREUZOT.

In 1853 some wealthy gentlemen sought for coal near Creuzot, in France. The spot was carefully selected, and for four years the work went on. The tools penetrated to a depth of more than three thousand feet. This is probably one of the deepest borings ever made. An unforeseen accident stopped the work at that point.

The bore-hole was less than an inch in diameter, and was made by means of a steel chisel fastened into wooden rods, which were screwed together. The boring tool one day became broken at the bottom of the hole. All kinds of grappling implements were lowered to take hold of it, but none of them succeeded. The chisel seemed to be firmly lodged at the bottom, and resisted every attempt to withdraw it. After six months of effort the work was abandoned. One of the parties interested offered to subscribe half a million francs to be given to any one who would invent an instrument that could withdraw the chisel.

Several days after the abandonment of the enterprise, the foreman of the work mounted the staging and made another effort to raise the broken tool. The whole power of the steam engine was exerted in pulling the ends of the rods, when suddenly the rope gave way. The man’s hand was caught and crushed between the rod and one of the planks through which it passed. He stood there and shouted to the man to saw off the rod in order to release him. Then holding the remains of the ruined hand in the uninjured one, he walked to Creuzot, three miles away, and without uttering a word of complaint, underwent amputation at the wrist.

TUBBING A SHAFT.

After the coal is discovered, whether through surface indications or by borings, the preliminary working begins by means of a shaft and levels. Generally the first step is to sink a shaft or pit. When the ground is soft, the pit must be walled with brick, stone, or timber, as fast as the descent is made. When the pit is sunk through limestone and sandstone, the progress is slow, but the walls sustain themselves, and do not require either masonry or timbering. A great inconvenience in sinking a shaft arises from springs and small streams of water. In many places where this inconvenience occurs, the shaft is fitted with a wooden lining, or tubbing, as it is called, which is made of thick staves somewhat resembling those of casks, the joints being carefully fitted, in order to keep out all water, and to withstand great pressure. Sometimes this tubbing is made of iron, wrought or cast. Where the ground is loose, or composed of sand and water, the tubbing is forced down from the top, or sinks by its own weight. When this tubbing consists of masonry, it is built in a circle at the surface, and as fast as the earth is removed the masonry sinks. A fresh circle is added at the surface, and thus the work goes on. It was in this way that Brunel constructed the shafts which formed the descent into the Thames Tunnel. Sometimes shafts are sunk under water, and in such case they are lowered in a perpendicular position until the ends strike the bottom, and then the water is pumped out. An ingenious apparatus raises the mud from the bottom, and a pump is kept at work to remove the water.

Sometimes, in sinking a shaft through quicksand, the water runs in faster than any ordinary mode of drainage will remove it. M. Triger, an ingenious Frenchman, invented a machine by which the water could be pumped out. The cylinders of iron were five or six feet in diameter, and he divided them into three compartments, as nearly air-tight as possible. He forced compressed air into the lower one, and enclosed the workman inside. The man was thus in a sort of diving-bell. The compressed air, being forced against the bottom of the shaft, prevented the great mass of water from filtering through the sand. The small quantity which filtered in was, by the force of the compressed air, driven through the sand pipe communicating with the surface. “Imagine an army of mice,” the inventor graphically said to M. Simonin, “and a cat suddenly to make her appearance, and you would have the picture of water reaching the bottom of our shafts through a thousand holes in the ground, if the presence of the air is lowered, and returning suddenly to the surface as soon as the air recovers its tension.”

The rubbish and running sands are removed in buckets by hand, or by means of a rope passing through a pulley. Trapdoors communicate from one stage to the other, by means of which the buckets are removed without any serious loss of the compressed air. Shafts may be sunk through quicksands in this way to a depth of eighty or one hundred feet without difficulty. The laborers who pass their time in the compressed air work as easily as in the open atmosphere. Some of them, however, cannot remain there long, especially if they have the drum of the ear very delicate, or are in the habit of drinking to excess. The pressure of air in the chambers rarely exceeds three or four atmospheres.

AN INGENIOUS APPARATUS.

This apparatus is frequently used for laying the foundation of bridges in the beds of rivers, where there are deep quicksands. The famous bridge of Kehl, near Strasbourg, was constructed in this way, and the engineers say that without some such apparatus the construction of the bridge would have been impossible.