INVENTION OF HYDRAULIC MINING.
I was once at a place near Grass Valley, California, where they were at work by means of hydraulic mining. A large cavity had been cut away under the base of the hill with the streams of water. Every moment the hill was expected to fall, but somehow it seemed to retain its position. One of the men incautiously ventured near it, and just as he had done so, the earth fell, and the man was partially buried beneath it. He screamed loudly with pain. His companions rushed forward to relieve him, when another mass of earth fell, partially burying two of those who had come to his rescue. Other men went to their assistance, and in a little while the three were extricated.
The first man had his leg broken, and one foot badly crushed. The other two were severely bruised, and the foot of one of them was permanently injured. It frequently happens that in this way men are killed or injured partially through want of caution, and partially owing to the dangers inseparably connected with hydraulic mining.
The force of water thrown in this way, with an enormous pressure, is almost wonderful. The solid earth is cut and torn away, and sometimes stones weighing several pounds are tossed into the air. The particles of earth fly in all directions. The water rebounds sometimes, and in a little while the men who manage the hose are thoroughly drenched. On a level surface a stream of water directed upon the solid earth at an angle of twelve or thirteen degrees, will cut a trench or furrow with the rapidity of a plough. When the earth falls, the largest blocks are broken up with the pick or with the streams of water, and the débris is thrown into a large channel, or flume, at the basis of the hill where the work is going on. The flume has riffles at its bottom, and many turnings, so that the gold may be saved. The stream of water carries away the earth, and leaves the gold behind.
DESTRUCTIVE EFFECTS OF THE SYSTEM.
There is no system of mining more destructive than this. Hills are cut away, and sometimes, for many acres, the rock is laid bare. The whole scene is one of desolation. The earth that is washed down fills the channels of rivers, and is sometimes carried a long distance. Before California was opened for gold mining, the water of her streams was perfectly clear; but since the beginning of mining the streams have lost their pellucid character, and the discolored water extends to the Bay of San Francisco, and sometimes out to sea. The lower part of the Sacramento River has been partially filled up, and there are parts of the great bay which are now much shallower than of old.
As the surface diggings of California showed signs of exhaustion, attention was given to mining in quartz rock. In the ledges of the mountain-sides veins were discovered rich in gold, and pieces of the rock taken from these veins gave promise of profitable working.
MINERS PROSPECTING.