Black Oak Mine (Black Oak group; Black Oak claim; Live Oak claim; White Oak; Carra claim; Carra Fraction claim), Soulsbyville, Soulsbyville & Confidence Mining District, East Belt, Tuolumne County, California, USAi

Regional Level Types
Black Oak Mine (Black Oak group; Black Oak claim; Live Oak claim; White Oak; Carra claim; Carra Fraction claim)	Mine
Soulsbyville	- not defined -
Soulsbyville & Confidence Mining District	Mining District
East Belt	- not defined -
Tuolumne County	County
California	State
USA	Country

A former lode Au-Zn-Fe-Pb mine located in sec. 1, T1N, R15E & in sec. 36, T2N, R15E, MDM, 1.4 km (4,700 feet) SW of Soulsbyville, on private land. Discovered in 1878. MRDS database accuracy for this location is not stated.

NOTE: Coordinates are based on the exact location of this mine on the topo map.

The Black Oak Mine exploited a typical East Belt gold deposit, which is characterized by a tabular hydrothermal quartz vein system that fills a fissure in country rock of granodiorite. Ore consists of ribbon quartz.

Mineralization is a hydrothermal vein deposit (deposit model code: 273; USGS model code 36a; Deposit model name: Low-sulfide Au-quartz vein; Mark3 model number 27) hosted in Jurassic granodiorite of the Standard pluton. The ore body is a pinch-and-swell body that strikes N15E and dips 60-70NW at a thickness of 7.62 meters. The vein swells from 1 to 25 feet in thickness. Several branches of this vein were identified coming from the hanging wall block. The diorite dike which intersects the fault zone is 1 to 2 feet thick, and strikes N55E with a vertical dip. The vein was found to be faulted 110 feet W on the 1,300 level. The course at the fault is N60E with a dip of 75N. The ore forms in kidneys and lenses at the intersection where a diorite dike crosses a fault zone. The ore shoot at the Black Oak Mine is about 800 feet long on all mine levels and is remarkably uniform as indicated by the constant gold content of the ore. On the 19th level, the shoot became too narrow for mining. The best ore was reportedly found in lenses at the intersections of 1-2-foot-wide diorite dikes with the vein in the vicinity of a fault that cuts the vein.

Workings include underground openings comprised of a 1,700 foot deep shaft on a 70 degree incline. On the 1700 level, the shaft is 16 feet in the footwall. Levels on the vein are 100 feet apart vertically. Stoping operations were performed at the 1000, 1300, 1400 and 1500 foot levels.

Production information: Clark (1970) reported a production value of $3.5 million (period values) for this mine. Reported to be the third largest producer in the East Belt in Tuolumne County.

Reportedly two ounces of Ag for every ounce of Au. Ore averaged 0.75 ounces of Au per ton.

Stope maps available prior to 1940 indicated that about three-quarters of the developed area of the 800-foot ore shoot had been mined. Amalgamation and cyanidation processes were used at this mine. The mine was under private residential ownership when visited by California Geological Survey staff in 2000.

Other Databases

Link to USGS MRDS:	10034515

Other Regions, Features and Areas containing this locality

References