Gold Districts of California
BIG OAK FLAT
Location. The Big Oak Flat district is in the East Gold Belt of the Sierra
Nevada in southwestern Tuolumne County. It includes the Groveland, Deer Flat and Second
Garrotte areas to the east.
History. This district was first mined shortly after the beginning of the gold
rush by James D. Savage. It was named for an oak tree that had a trunk with a diameter of
11 feet. The placer deposits here were highly productive, those at Big Oak and Deer Flat
having been credited with a production of $25 million. Lode mining began soon afterward,
and continued steadily until World War 1. The town of Garrotte was renamed Groveland by
later residents who replaced the name given in 1850, when a thief was hanged there. But a
place to the cast, named Second Garrotte (after 1850) for a similar reason, has kept its
19th Century name. This area has prospered from tourist trade that originates along the
Big Oak Flat road, which serves Yosemite National Park. The Hetch Hetchy Railroad, which
was used in the construction of the San Francisco Water Department's Hetch Hereby
Reservoir to the east, served the area for some years. Some lode mining was done in the
district again in the 1930s, and there has been intermittent prospecting and development
work at several mines since.
Geology. The area is underlain by a northwest trending belt of schist,
argillite, and quartzite of the Calaveras Formation (Carboniferous to Permian), intruded
by several small granodiorite stocks and flanked on the west by amphibolite, slate, and
serpentine of the Mother Lode belt.
Ore deposits. A considerable number of north, northwest and west-trending quartz
veins are found in both the metamorphic rocks and the granodiorite. The ore shoots usually
are limited in extent, but often are rich. The ore contains free gold and often abundant
sulfides, especially galena. Most of the veins are only a few feet thick. The surface
placers mined during the gold rush were extremely rich.
Mines. Bicknell, Champion, Contact, Criss Cross, Del Monte, Goodnow, Kanaka,
Long Fellow $100,000+, Mack, Mississippi, Mohrman $40,000, Mr. Jefferson, National,
Nonome, Red jacket, Rhode Island, Venus, Wide West.
Excerpt from: Gold Districts of California, by: W.B. Clark, California
Department of Conservation, Division of Mines and Geology, Bulletin 193, 1970.
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