There was very little geological or other science applied to the early mining, as very few of the miners had any knowledge in that direction beyond what they acquired by practice. Men dug where they could find pay-dirt, and abandoned places that did not pay for their labor, but they could not often give any reason why one spot in a valley was richer than another. Mining was almost wholly a matter of experiment, and to this day the theories of the school of mines are of comparatively little value in the eyes of many miners. Many of the ordinary rules of geology are overthrown in the formation of the Pacific coast, so that the scientific geologists who have gone to California, find themselves involved in perplexities at almost every step.
The revelations of General Sutter’s mill-race established the existence of gold in California, and the news spreading rapidly throughout the world, brought a large migration. The first miners were nearly all adventurers without capital, and though the bulk of the immigration continued of this character, the second and subsequent years saw men of capital and intelligence going there to give a better direction to the interest of the country. The pick and pan, the primitive rocker, the long tom, the sluice, the tunnel, and other accessories of placer mining, marked the successive development of means for robbing the earth of its treasures. These operations culminated in hydraulic mining, which may be fairly considered as the perfection of this branch of work.
Of course it was but a single step from the discovery of gold in the dirt of the valleys, to its discovery in the veins of rock that formed the hill-sides and mountains. The rock from these veins was carefully assayed, and its richness established. Mere hand work was of no avail, or would be unprofitable in reducing these ores and extracting the metal. Heavy machinery must be erected, deep mines must be opened; shafts and wheels and pits would be expensive, and so would be the erection and management of machinery. Hence the necessity for capital and intelligence in this kind of labor. Individuals and companies led off in this work, and so quartz mining followed upon placer mining, and became a business of magnitude.
QUARTZ MINING.
The best established gold mines in California are at Grass Valley, a neat little city in Nevada County, twelve miles from the Central Pacific Railway, and for some time the home of the once noted and notorious Lola Montez. The other quartz mining districts are scattered through the mountainous region of the State, but the localities where the mines are profitable are not very numerous. Further explorations will of course increase their number, but it is not very probable that the development will be rapid.
In placer mining, the object is to separate the gold from the dirt where it has been deposited, and to accomplish this, water and labor are the only necessities. The dirt or earth is to be carried away while the gold remains. This is the whole process, whether we employ the simple pan and rocker or some more elaborate means of working. But in quartz mining the process is more complicated. The rocks must be taken from the veins and brought to the surface. There it lies, solid rock, with the gold mixed into its whole mass, while in a fluid state, just as salt or soda are mixed with flour in making bread. It must be reduced to powder, and for this purpose heavy machinery is employed. When reduced to a powder, the gold must be extracted, and this work requires more care and causes more perplexities than other labor connected with quartz mining. Besides the gold, there are various chemical compounds, some of which remain, while others may be washed away. Many men must be employed about a quartz mill; the monthly disbursements, provided the owners are honorable, are very large. Hence, while a man without capital may become a miner in the gulches and placers, the beginner in quartz mining requires both brains and capital.
The quartz district, which is from fifteen to a hundred miles in width, commences in Mariposa County, and extends along the western foot-hills of the Sierra Nevada for four or five hundred miles, disappearing somewhere in Oregon. The ledges of rocks lie at various angles, being in some places almost horizontal, while in others they vary little from the perpendicular. There are various theories touching the formation of the quartz ledges and their impregnation with gold, but none of them will apply to all cases. The mines that have been opened are along this ridge, and many shafts have been sunk for the purpose of reaching this rich rock. A considerable proportion of these shafts have been abandoned because they did not reach the ledge, while others have been forced to quit, because the ledge, though containing gold, was unprofitable. As before stated, those most generally successful are at Grass Valley, where the rock does not vary much in value, and where the profits of a year’s labor can be estimated beforehand with considerable accuracy. Year after year the work has gone on, and the town of Grass Valley has a more thrifty appearance than the majority of the mining centers of California.
There is very little difference in the character of the quartz mines and mills throughout California. Where the vein is perpendicular, or nearly so, the shaft is sunk directly through the vein; but where it lies at an angle, the shaft is sunk so as to strike the vein at a given distance from the surface. In either case, galleries, called levels, are run off from the shaft into the vein, sometimes for a long distance. At the surface, the vein may be but a few inches in thickness, but it gradually widens as it descends, so that some of the veins have a width of twenty-five feet or upwards. Along the levels the ore is brought to the shaft, and then sent, in buckets, up to daylight. In extensive operations, there are numerous shafts, galleries, and levels that connect with each other and form a subterranean network of streets and alleys. Once on the surface of the earth, the ore is sent to the mill, where it is first broken into small pieces and then reduced to powder by the action of the crushing machinery.
Various kinds of machinery have been devised for reducing the ore, the first being the stamp-mill, which consists of a row of heavy pestles, standing in troughs. These pestles or stamps are raised by steam power, and fall by their own weight. They are from four to eight in number, and sometimes there are twenty or more; they operate just as do the feet of the smiling maidens in the vineyards of France, when treading out the juices of the grape. No other mill has proved superior to this in reducing the ore; the testimony of miners and capitalists is almost unanimously in favor of the stamp-mill.
A stream of water pours into the trough where the ore is being crushed, each stamp falling from ten to eighty times a minute, and mixing the water and pulverized rock together. This runs upon blankets, which catch a portion of the gold; then it passes over a sloping surface, cut with horizontal crevices, filled with quicksilver, that catches all the gold it touches; then through a series of troughs and sluices, with occasional beds of quicksilver, and so on to a heap of wastes.