Oro Fino Mine, Seventeenmile Point, Old Dad District, Old Dad Mountains, San Bernardino County, California, USAi

Regional Level Types
Oro Fino Mine	Mine
Seventeenmile Point	Point
Old Dad District	Mining District
Old Dad Mountains	Mountain Range
San Bernardino County	County
California	State
USA	Country

A former lode Au occurrence/mine located in sec. 23, T13N, R10E, SBM, 2.3 km (1.4 miles) S of Seventeenmile Point (coordinates of record) (7 miles NNW of the summit of Old Dad Mountain), on federal reservation land (Mojave National Preserve/East Mojave National Scenic Area). The property is comprised of 4 claims. MRDS database stated accuracy for this location is 10 meters. First prospected in 1890's.

Mineralization is a vein deposit hosted in Neoproterozoic quartzite, mica schist and dolomite. The ore body is lenticular in form, strikes E, N60E and dips N, 30-60NW at a thickness of 3.66 meters. Controls for ore emplacement included fractures and a fault zone. The ore shoots are siliceous at 4 to 6½ feet thick and occur along faulted and fractures zones that are now discontinuous, The ore shoots are commonly bordered on one side by a gouge that appears to consist mostly of pulverized dike material. The faulted and fractured zones may represent offset segments of a single zone. Displacement of each stepped segment amounts to a few feet. The host rocks vary from quartzite (West part), mica schist and dolomite (East part). The dikes are basic. The ore bodies occur in an E-trending belt, about 1,200 feet in length. The ore is up to 75% free gold. Local rocks include Precambrian rocks, undivided, unit 2 (Mojave Desert and Transverse Ranges).

Workings include underground openings with an overall depth of 30.48 meters. There are 3 main groups of workings, the West, middle and extension (East). There are 2,500 feet of shafts and tunnels. The deposit was prospected along the length of its outcrop for 1,500 feet. A tunnel was driven on cross fracture N25E, 175 feet to the main vein, then 150 feet N60E. This work exposed an ore shoot 150 feet long that averaged 7 feet thick. A raise was driven 87 feet upward to surface 260 feet from the portal. Numerous cuts and shallow shafts for 1,300 feet NE along the tunnel. 1,300 feet NE of the main tunnel is a shaft 65 feet deep. A stope on the 30 foot level, 60 feet long, 6 feet wide and 30 feet high.

Production data are found in: Wright, L.A., et al (1953).

Analytical data results: Ore mined from the NE-trending vein averaged $9 (period values) Au/ton. Result of $50 (period values) Au/ton from stoped area.

Other Databases

Link to USGS MRDS:	10035787

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References