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Zantgraf Mine (Montauk Consolidated Zentgraf), Goose Flat, Rattlesnake Bar District, El Dorado Co., California, USA

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A former lode Au-Pb occurrence/mine located in the SW¼SW¼ sec. 16 & in sec. 21, T11N, R8E, MDM, 1.6 km (1.0 mile) S of Goose Flat (1 mile S of Rattlesnake Bridge on the E side of the American River; 4½ miles SW of Pilot Hill). MRDS database accuracy for this location is not stated.

This mine was first worked in 1880 and in 1888 a mill was in operation. It was active during the 1890's and the mill was enlarged. Between 1898 and 1901 it was operated by the Montauk Consolidated Mining Company. It was idle until 1924 when a small amount of prospecting was done and again during the period 1933 to 1938, and again in 1941, when the property was prospected and some Au was produced. Idle since that time.

Mineralization is a vein deposit hosted in granodiorite, amphibolite and diorite. The ore body strikes NW and dips 45SW at a thickness of 1.83 meters. Several sub-parallel veins dip 38-50SW, accompanied by diorite dikes. Amphibolite lies to the E. Most workings are in granodiorite in the main vein, or Zantgraf vein, which is from 2 to 6 feet thick. The ore shoot was stoped from the 300 foot level to surface for a distance of 900 feet. A second ore shoot exists on the lower levels. A third ore shoot is 900 feet NW of the main shaft. The ore contained free gold with associated auriferous pyrite and galena. Local rocks include ultramafic rocks, chiefly Mesozoic, unit 2 (Western Sierra Nevada and Klamath Mountains).

Workings include underground openings comprised of a 1,130 foot inclined shaft with levels at 100 foot intervals. A 500 foot crosscut adit joins the shaft on the 300 foot level. A 190 foot shaft was sunk on the Montauk vein. A third shaft is 200 feet deep. Also, drifting and stopes.

Production data are found in: Clark, Wm. B. & D.W. Carlson (1956).

Production statistics: Year: 1901: Period: 1880 to 1901: Au = 10 grams/metric ton. Year: 1938: Period: 1933 to 1938: Au = 6 grams/metric ton.

No record of production value after 1901 was found. Values of ores ranged from $2 to $100 (period values) per ton, but averaged between $7 and $8 (period values) per ton. A small amount of Au was produced in 1924. Nearly all the ore that was mined was from the main or Zantgraf vein. Total output of the mine up to 1902 was valued at about $1,000,000 (period values).

Mineral List

4 entries listed. 3 valid minerals.

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Logan, Clarence August (1938), Mineral resources of El Dorado County: California Journal of Mines and Geology, California Division Mines (Report 34): 34(3): Pl. II.

Clark, Wm. B. & D.W. Carlson (1956), Mines and mineral resources of El Dorado County, California: California Journal of Mines and Geology: 52(4): 429, 540, Pl. 10.

USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10006822 & 10029641.

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