W.Y.O.D. Quartz Mine (W.Y.O.D. Qtz; W.Y.O.D. vein; Work Your Own Diggings Mine; Cassidy Consolidated Extension Mine), Pennsylvania Mine [1] (Pennsylvania Consolidated Qtz; Pennsylvania-W.Y.O.D.; Pennsylvania vein; Pennsylvania-Wyod; Wyod), Empire Star group (Empire Star Mines Company holdings), Grass Valley, Grass Valley Mining District, Nevada County, California, USAi

Regional Level Types
W.Y.O.D. Quartz Mine (W.Y.O.D. Qtz; W.Y.O.D. vein; Work Your Own Diggings Mine; Cassidy Consolidated Extension Mine)	Mine
Pennsylvania Mine [1] (Pennsylvania Consolidated Qtz; Pennsylvania-W.Y.O.D.; Pennsylvania vein; Pennsylvania-Wyod; Wyod)	Mine
Empire Star group (Empire Star Mines Company holdings)	Group of Mines
Grass Valley	Valley
Grass Valley Mining District	Mining District
Nevada County	County
California	State
USA	Country

A former lode Au-Zn-Pb occurrence/mine located in secs. 34 & 35, T16N, R8E, MDM, about 1/3 mile E of Grass Valley, on private (patented) land. The property comprises 16.24 acres. MRDS database accuracy for this location is not stated.

Mineralization is a banded vein deposit hosted in slate and granodiorite. The ore body is seam with stringers, strikes N6W and dips 38SW at a thickness of 0.91 meter. The vein averaged 18 inches (45 cm) thick and carries an average of 3% sulfides. Local rocks include Mesozoic granitic rocks, unit 3 (Sierra Nevada, Death Valley area, Northern Mojave Desert and Transverse Ranges).

W.Y.O.D. vein: East of, and in the foot wall of, the Pennsylvania vein is the W.Y.O.D. vein. This vein strikes to the south and has an average dip of 32W. Long known as a minor surface vein as small as 3-6 inches (7.5 to 15 cm) wide, it was found to develop with depth in the early 1890's. Followed downward, the vein widened to 10 inches (25 cm) at 500 feet, 2 feet (60 cm) at 620 feet, and 2.5 feet (75 cm) at 700 feet. South of the W.Y.O.D. Mine, the vein enters diabase and turns more southeasterly and increases in dip. The vein is generally narrow, locally reaching 2 feet (60 cm) wide and sometimes closing to a seam. The country rock is fractured and impregnated with pyrite and a little calcite. Cavities filled with quartz crystals are common in the vein. Comb, massive, and sheared quartz is the principal gangue material and is accompanied by minor amounts of carbonate.

The ore consists of quartz with finely disseminated gold (806-832 fine) and averages $20 - $50 per ton. Pyrite, galena, sphalerite, and some arsenopyrite are the principal sulfides making up about 2% of the vein material and averaging 2.5 to 4.5 ounces of gold and 5 to 8 ounces of silver per ton.

Annual production from the W.Y.O.D. vein in the W.Y.O.D Mine for the four years 1890-1893 was $26,000, $53,500, $108,700, and $143,360 (period values).

Workings include underground openings with a length of 1,158.24 meters and an overall depth of 518.16 meters and comprised of a shaft, raises and drifts.

Production data are found in: Hobson (1890).

At the 500 foot level, the W.O.Y.D. vein yielded $18 to $20 (period values) Au/ton. At the 700 level it was $50 Au/ton plus sulfides averaging $250 to $300 (period values). Production grade values based on Au at $20.67 ounce.

Some high-grade ore yielded 7 to 8% sulfides valued at $250 to $300 (period values) per ton. Some production data may be included with the Pennsylvania Mine (MacBoyle (1918), pages 234-235).

Other Databases

Link to USGS MRDS:	10007473

Other Regions, Features and Areas containing this locality

References