While the gold fields in the southwestern part of Oregon were discovered about 1852, those of the Blue Mountains remained unknown until about ten years later.
The Elkhorn district was prospected early in the history of the State and numerous quartz locations were made in the years preceding 1870, but the district did not attract attention until the A. M. Holter lode became a producing mine.
The following notes concerning the metal prospects of the Los Burros district, in the southwestern part of Monterey County, California, are based on observations made during a visit of a few days to this section of the Santa Lucia Range in February, 1921.
Tourists will naturally desire to visit some of the towns, where they can observe closely the various operations connected with gold-mining, which is such an important industry of California. This can be done by leaving the main line of railroad at any station in the mining-region and going a little way into the country. Indeed, on the main line of the Central Pacific are several towns, where almost the only occupation of the people is gold-digging.
In the early days of lode gold mining, stamp mills were used for crushing the ore. Where there was free gold in the ore, a silver-plated copper plate was placed so that the discharge through the screen from the mortar, with the addition of water, flowed down over this plate which was coated with quicksilver, allowing the free gold to become amalgamated and retained on the plate. The man who operated such a mill was called an amalgamator.
As the title suggests, the subject matter in this book deals for the most part with the examination and testing of placers. It is intended primarily as a guide for the professional mineral examiner who examines mining claims located on public lands of the United States.
When the Berkley mine broke out afire the other day in Butte, Montana, sending five hundred men to the surface and suspending operations for a month in one of the biggest producers of the greatest mining camp on earth -- the camp that gives to the world's market one-fourth of its copper production -- the sight of the flames and smoke didn't cause as much as a ripple of excitement on the surface of the busy population at the foot of the hill, for Butte is accustomed to a mine fire that is perpetual and which burns with intense heat in the ground under her very business district.
The Spenceville Copper Mine, located in Spenceville, Nevada Co., California, operated between 1863 and 1918. In its day, it was considered one of the most long-lived copper mines in the state.
Among the comparative tests the most remarkable was that in Cornwall, England, where the Ingersoll drill worked in competition with the diamond drill, when the former bored the same depth of hole in half the time it could be accomplished by the diamond drill.
The substitution of a mechanical power in place of the hand-labor formerly exclusively used for drilling rock, has been a subject of much thought, and many attempts have been made, with greater or less success, until the rock drill by improved machinery became of late years a firmly established institution, and the credit of this belongs, to a great extent, to the improvements made by Mr. Ingersoll, as he overcame the defects connected with former attempts, which were excessive weight, imperfect action, easy derangement, frequent damage, and costly repair.