Shortly before reaching the sea, however, the works became more complicated. The "Wizard" and Owens—one with Arctic and the other with Australian and South African experience—had arranged a system of separating the gold bearing gravel from the bowlders, and, later, the unproductive material from that which contained the precious metal. The smaller, gold-bearing part was washed into the stamp-mills, which worked incessantly, and which reduced pebbles and grit and sand and gold to a pasty slime. This, in turn, was led to cyanide tanks. Thus every particle of the gold was extracted.
Hydraulicking was not altogether new to Jim. He had seen it done on a giant scale, as in California during the seventies, when huge reservoirs and mile-long canals were built at a cost of many millions. Vast works these, belonging to a short and strange era of mining, immense constructions, now lying ruined and abandoned in the deserts of their own making.
That was before the farmers and fruit-growers of California had succeeded, in 1884, in securing the passage of a law to prevent "slicking," as hydraulicking was termed. It was time! Vast stretches of territory were being reduced to chaos by the appalling havoc which follows hydraulic operations on a large scale.
Many rivers were entirely choked by debris from the crumbled mountains and spread their waters in destructive floods. On one small stream alone, the Lower Yuba, over 16,000 acres of high-grade farm lands were reduced to a condition which an official investigator for the state declared "could not have been surpassed by tornado, flood, earthquake, and volcano combined."
Hydraulicking in Colorado.
The "Snowstorm Placer," a typical modern pay-gravel plant.
From "The Business of Mining," by A. J. Hoskins. J. B. Lippincott & Co.