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Gwin Mine, Rich Gulch, Paloma, Mother Lode Belt, Calaveras Co., California, USA
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Latitude: 38°16'33"N
Longitude: 120°45'29"W

Longitudinal section of the Gwin gold mine..

A former lode Au mine located 1.9 km (6,100 feet) SSW of the old town of Paloma and 4 miles SW of Mokelumne Hill. Mine started about 1850 by Dr (MD) William McKendree Gwin, of Tennessee, later Senator from California. The Gwin Mine was one of the most productive Mother Lode gold mines in Calaveras County with an estimated output of between 6 and 7 million dollars at period gold values. The mine earned millions of dollars for Gwin.

The Gwin mine is located in the same belt of Mariposa slate that contains the highly productive Mother Lode mines to the north in Amador County. This belt is approximately 2000 feet wide in the Gwin mine area.

The following information is extracted from the U.S. Geological Survey Mother Lode folio: "South of the Mokelumne River, the Gwin mine is situated in a belt of Mariposa slates which is directly continuous with the slates of the Kennedy and Argonaut mines. The Gwin vein strikes with the slates and is generally parallel with their cleavage. It is accompanied by stringers and varies in width, but on the whole is entitled to be called a simple vein rather than a stringer lead.

The vein minerals are Quartz, Pyrite, Arsenopyrite, Free Gold, Chalcopyrite, Galena, Zinc Blende (Sphalerite), Albite, Sericite and Calcite. Galena and Sphalerite, when present in small amounts, are considered to indicate good ore. The Arsenopyrite is found in both large and small crystals. the former are particularly prized, as they inclose beautiful arborescent masses of crystallized Gold.

The mine is developed by the 2533-foot vertical main shaft, the 1800-foot inclined south shaft, and several old shallow shafts. There are more than 25,000 feet of underground workings at the Gwin mine. The 100-stamp mill used in the last operations was driven by water power and was equipped with Frue vanners. No equipment remains on the property.

Production was some 300,000 ounces of gold worth $139,000,000 in todays dollars.

Mineral List

var: Sericite


10 entries listed. 9 valid minerals.

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Ransome, Frederick Leslie (1900), Description of the Mother Lode district, California: USGS Geol. Atlas, Mother Lode (No. 63), 11 pp.: 8.

Clark, William B. & Lydon, Philip A. (1963), Mines and Mineral Resources of Calaveras County, California, California Division of Mines and Geology, County Report No. 2: 56-59.

Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 86.

Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 12 (map 2-3).

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