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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Page 8
... rock assay- ing less than $ 50 per ton unprofitable , and prevented any ... dredging operations . Origin of Hydraulic Mining The thousands of emmigrants ... gravel deposits , mining in California would have 8 Origin of Hydraulic Mining.
... rock assay- ing less than $ 50 per ton unprofitable , and prevented any ... dredging operations . Origin of Hydraulic Mining The thousands of emmigrants ... gravel deposits , mining in California would have 8 Origin of Hydraulic Mining.
Page 31
... gravels to merge gradually into the sediments of the valley . These gravels are gold - bearing at many places and in recent years have been the field of extensive dredging oper- ations . Distribution of Gold in the Gravels As might be ...
... gravels to merge gradually into the sediments of the valley . These gravels are gold - bearing at many places and in recent years have been the field of extensive dredging oper- ations . Distribution of Gold in the Gravels As might be ...
Page 33
... gravels in beach and fluviatile deposits , both ancient and recent . In their original condi- tion they form but a ... dredging operations where it is recovered by panning the black sands after the gold has been amalgamated . Some very small ...
... gravels in beach and fluviatile deposits , both ancient and recent . In their original condi- tion they form but a ... dredging operations where it is recovered by panning the black sands after the gold has been amalgamated . Some very small ...
Page 42
... gravels of the Sierra Nevada , large areas of which are covered by volcanic flows , the Qua- ternary dredging gravels along the edge of the Great Valley , and the shallow gravel deposits derived in geologically recent time from the two ...
... gravels of the Sierra Nevada , large areas of which are covered by volcanic flows , the Qua- ternary dredging gravels along the edge of the Great Valley , and the shallow gravel deposits derived in geologically recent time from the two ...
Page 43
... gravels of Tertiary age ; dredging operations have , up until the present , been confined to the Quaternary gravels along the edge of the Great Valley , but may in the near future find a commercial application in the exploitation of ...
... gravels of Tertiary age ; dredging operations have , up until the present , been confined to the Quaternary gravels along the edge of the Great Valley , but may in the near future find a commercial application in the exploitation of ...
Common terms and phrases
alluvium amalgamated andesitic annual gold production auriferous gravels average Black Sands bucket CALIFORNIA GOLD PRODUCTION canyons cent channels Chapter Four chlorine concentration counties country rock Cretaceous cyanide process dams deep gravels depth drift mining duction early erosion exchange value feet flows flumes geologic gold and silver gold dredging gold industry gold mining gold quartz gold-bearing granitic Grass Valley gravel deposits Ground Sluicing hydraulic mining industry in California investment material METALLURGY metals metamorphic rocks mills miners mining in California mining industry mining operations Mother Lode Nevada City output period pipe placer gold placer mining Pliocene preceeding present primary gold deposits Production of California quartz mines quartz veins Quaternary Quaternary gravels range result rhyolitic rich riffles Shore line moves Sierra Nevada silver industry sluices streams sulphides sulphurets surface placers tailings tons Total Gold Production total gold yield total placer production treated valley border volcanic washing
Popular passages
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...