The Rise and Decline of the Gold Industry in California: A Summary of the History and Present Practice of the Gold Industry in California and a Discussion of Its Future ...

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Stanford University, 1924 - Gold mines and mining - 216 pages
 

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Page 14 - Federal funds for the removal of wrecks or other obstructions shoreward of established harbor lines. § 209.160 The California Debris Commission. Section 1 of the Act of Congress of March 1, 1893 (27 Stat. 507; 33 USC 661) , created the California Debris Commission, consisting of three officers of the Corps of Engineers, to regulate under the supervision of the Chief of Engineers and direction of the Secretary of the Army, hydraulic mining in the territory drained by the Sacramento and San Joaquin...
Page 21 - ... the old channels remained secure below their blanket of 1,000 feet of hardened volcanic mud. Wherever the canyon-cutting streams destroyed the old channels the gold in those channels became concentrated in the canyons and thousands of disintegrated quartz veins added to the previous concentrates; but owing to the steep grades of the Quaternary rivers much of the detrital material and the fine gold was swept out into the valley at the western foot of the range over alternately advancing and retreating...
Page 14 - Under the Act, the California Debris Commission, consisting of three officers of the Corps of Engineers, USA, was appointed by the President. This Commission is empowered to issue licenses for mining by the hydraulic process under this Act, when it is satisfied that the de.bris dams or impounding works are sufficient to restrain the debris. The hydraulic miner must make application to the Commission for a license...
Page 19 - In consequence of this disturbance the monoclinal nature of the range became strongly emphasized and the streams immediately began to cut their beds deeper; they repeatedly crossed their old courses and the concentration of gold in the new canyons proceeded under less favorable torrential conditions. Eruptions of andesitic tuffs began in enormous volume and effectually buried a large number of the streams, filling their valleys to the rims.
Page 18 - Joaquin valleys, or caused these watercourses to debouch upon flood plains reaching high up on the flanks of the range. Faulting movements, with downthrow on the east side, probably beginning in Cretaceous time, had transformed an approximately symmetrical range to a monoclinal one with steep easterly slope. Gradually the mountains were thus reduced to gentler slopes and the canyons widened to valleys. Meandering among longitudinal ridges, the rivers flowed from low divides to rolling foothills and...
Page 15 - Commission, at which those who may be opposed to the issuance of a license may state their reasons. When the plans are approved, and the necessary works constructed, members of the Commission make a personal examination of them, and, if satisfied that the de.bris can be restrained, a license to mine by the hydraulic process is issued, and the mine may begin operations. If they see any reason to believe, however, that damage may be done to the rivers or to individuals by the operation of the mine,...
Page 70 - The main body of liquid, on the other hand, moves in the opposite direction to the course of the ore and is gradually enriched. By each step of the system a large amount of low-grade solution is mixed with a very small amount of higher-grade solution, so that the value of the solutions entering each successive thickener i* materially reduced.
Page 104 - ... shift of men and all of them had to restrict operations, owing to lack of skilled labor. Such labor as was available was less efficient than usual, being mainly men either too young or too old, and much loss was due to this condition. It must be remembered also that few of the larger deep-mine gold producers were anxious to push production under costly conditions and pay resultant war income taxes. Their mines had to be kept in operation, but not necessarily up to capacity. Not only were costs...
Page 18 - ... gentle outlines, permitted deep rock decay and promoted the liberation of gold from its matrix. Renewed uplift quickened erosion and facilitated the further concentration of gold. Throughout Cretaceous and Tertiary time these conditions continued. Fluctuations of the western shore...

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