The numerous serpentine bodies and associated mariposite rock are structurally important in the localization of the ore bodies. The gold occurs in the native state commonly with arsenopyrite but only smaIl amounts of other sulfides. One ore body at the Sixteen-to-One mine, which had a pitch length of 40 feet, contained nearly $1 million, while another at the Oriental mine about 14 feet long yielded $734,000. They range from small masses of gold and quartz yielding a few hundred doIlars to ore bodies that have yielded hundreds of thousands of dollars. The most characteristic features of the ore deposits are the extreme richness, erratic distribution and small size of the ore shoots. The largest number of mines are in amphibolites of the Tightner Formation. They occupy minor reverse faults, and occur in all of the rocks of the Calaveras Formation, and in the greenstone. The gold-quartz veins strike in a northerly direction, dip either east or west, and usually range from two to five feet in thickness. The higher ridges are capped by andesite and basalt, which in places overlies auriferous Tertiary channel gravels. Also present are fine to medium-grained dioritic dikes. Mariposite-bearing rock, locally known as "bluejay," is commonly adjacent to the serpentine. These rocks have been invaded by many basic and ultra-basic intrusions the ultra-basic rocks have been largely serpentinized. In the vicinity of Alleghany and Forest this formation has been divided into six units: Blue Canyon Slate, Tightner Formation (chiefly amphibolite and chlorite schist), Kanka Formation (conglomerate, chert, and slate), Relief Quartzite, Cape Horn Slate, and the Delhi Formation (phyllite and slate). The district is underlain by north and northwest-trending beds of metamorphic rocks of the Calaveras Formation (Carboniferous to Permian), serpentine, and greenstone. Much of this production was from small but spectacularly rich ore bodies.
The value of the total output is unknown, estimated at $50 million.
RUBY MINE SIERRA NUGGETS SKIN
Skin divers are active in the streams of the area.Īlleghany was the most famous high-grade gold mining district in California. Several of the mines received Federal exploration loans. Intermittent operations have continued at several mines, such as the Kate Hardy, Oriental, El Dorado-Plumbago, and Mugwump mines. At the end of 1965 the Sixteen-to-One mine was completely shut down, ending an operation that had lasted more than 60 years. The Sixteen-to-One mine, the largest gold source in the district, curtailed normal operations late in 1962, and the Brush Creek mine, the second largest operation, was shut down in 1964. By 1963, the output was less than $100,000 per year. After 1960, production from the district, which had been averaging more than $500,000 per year, decreased greatly as more and more mining operations were curtailed. Johnson (erroneously given as 1907 in many reports) led to the revival of lode mining, which continued until 1965.Īlleghany was the only town in California after World War II where gold mining was the principal segment of the economy. The rediscovery of the Tightner vein in 1904 by H.
Although the quartz mines were moderately productive until the 1870s, drift mining was the principal source of gold then. Quartz mining was reported to have begun in the district in 1853 at the German Bar and Irelan mines. The town of Alleghany was named for Alleghany, Pennsylvania. Hydraulic mining was done at Minnesota and Chip's Flat during these years. The Bald Mountain and other drift mines were highly productive from then until around 1885. Forest, first known as Brownsville and then Elizaville, got its present name in 1853.
Some of these sailors were "Kanakas" or Hawaiians who also had deserted their ships in San Francisco. The streams in the area were placer-mined soon after the beginning of the gold rush, and the Forest diggings were discovered in the summer of 1852 by some sailors. The Downieville and American Hill districts are to the east, and the Pike district is to the west. This gold-bearing belt continues south to the Washington district in Nevada County. This district is in a belt of gold mineralization that extends from Goodyear's Bar, south and southeast through Forest, Alleghany, Chip's Flat, and Minnesota. Alleghany is in southwestern Sierra County.
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