By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
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Gold was discovered in Calaveras County in 1849 in gravels along Carson Creek, a tributary of the Stanislaus River. In 1850, rich lode deposits were found above the placer diggings on Carson Hill, where a single nugget from the outcrop was valued at more than $40,000 (Julihn and Horton, 1938, p. 12).
Many methods of placer mining have been utilized in working the Quaternary deposits in this county: hand rocking, sluicing, hydraulicking, dredging, and dragline operations. The rich auriferous channel gravels of the Tertiary Calaveras River and the Cataract or Table Mountain channel have been mined by drifts. Most of the production from 1880 through 1959 was from lode mines in the Mother Lode, East Belt, and West Belt districts.
There is no record of production before 1880, when mining of the rich placers was at its peak, but Julihn and Horton (1938, p. 21) estimated that the placers yielded a minimum of $50 million (about 2,415,000 ounces) in gold in the early years. From 1880 through 1959, a total of 580,600 ounces of gold was mined from placer deposits, and 2,045,700 ounces, from the siliceous ores of the Mother Lode, East Belt, and West Belt. Production since 1950 decreased sharply; in 1959 the county produced only 167 ounces of gold.
The Mother Lode, East Belt, and West Belt districts have produced nearly all the lode gold reported from Calaveras County. Copper ores in the Campo Seco district have yielded a relatively small amount of gold. Important placer localities are along the channel systems of the Tertiary Calaveras River and the Tertiary Table Mountain channel, and Quaternary gravels have been highly productive at Jenny Lind and Camanche.
CAMANCHE DISTRICT
The Camanche district is in northwest Calaveras County, near the Mokelumne River.
Gold was recovered, by bucket-type dredges and draglines, from late Tertiary or early Quaternary gravels, some of which are in the flood plain of the Mokelumne River. Production is not known, but 100,000 to 1 million ounces is estimated.
CAMPO SECO DISTRICT
The Campo Seco district, in Tps. 4 and 5 N., R. 10 E., in northwestern Calaveras County, has yielded gold from Quaternary gravels of the Mokelumne River and also as a byproduct of copper ores.
Most of the placer mining was before 1900, and the amount of gold produced in those early operations cannot be estimated. Most of the byproduct gold was from the Pern mine, which operated from 1899 to 1919 (Julihn and Horton, 1938, p. 112).
During that time an estimated 800,000 tons of ore was mined which contained 0.03 to 0.10 ounce of gold per ton, or a total of 40,000 to 50,000 ounces. The mine was inactive until 1937, when the workings were unwatered, and copper was recovered from the mine water. Significant amounts of gold were produced during the 1940's, but after World War II when the demand for copper ceased, the mine became dormant. Total gold production of the district was about 60,000 ounces.
The geology of the area was discussed briefly by Julihn and Horton (1938, p. 112-113). The ore bodies are massive sulfide replacement bodies in zones of amphibole schist and sericitized greenstone. The ore consists of an intimate mixture of fine-grained pyrite, chalcopyrite, and sphalerite, and smaller quantities of bornite and tetrahedrite.
JENNY LIND DISTRICT
In the Jenny Lind district, in T. 3 N., R. 10 E., along the Calaveras River, Quaternary and late Tertiary gravels have been mined on a large scale by dredges and draglines. The gold production is unknown but is probably between 100,000 and 1 million ounces.
MOTHER LODE, EAST BELT, AND WEST BELT DISTRICTS
The Mother Lode, East Belt, and West Belt districts compose a north-trending belt in the western part of Calaveras County that contains about 800 lode mines and prospects (Julihn and Horton, 1938, p. 94). These three districts are combined here because it has not been possible to assign specific production data to any one district nor to determine with any degree of accuracy which mines are in which district.
The first lodes discovered in the county were on Carson Hill, on the Mother Lode, where extremely rich gold-quartz ore was found in wallrocks adjacent to the vein outcrops. The discoveries precipitated a rush to the area which culminated in the founding of the town of Melones and the feverish exploitation of the rich ores of the now-classic Carson Hill (Julihn and Horton, 1938, p. 101-102).
Elsewhere in the county, quartz mining developed more slowly. In the 1890's mines near Angels Camp boosted the output of Calaveras County above that of Amador County (Knopf, 1929, p. 6). The mines on Carson Hill have been the most productive in the county. By 1938 they had yielded a total of about $25 million in gold (Julihn and Horton, 1938, p. 107). At Angels Camp the Utica and Gold Cliff group produced gold valued at $16,400,000 (Julihn and Horton, 1938, p. 136).
In the West Belt district, the Royal mine, discovered in the early 1870's, was the most important; to about 1938 its production was valued at about $3 million (Julihn and Horton, 1938, p. 117). The Sheepranch mine, the deepest and most productive in the East Belt district, had yielded about $5 million in gold by 1938 (Julihn and Horton, 1938, p. 110).
After 1950, lode mining in Calaveras County declined markedly; only a few ounces was produced in 1957-58. Total production from 1880 through 1959 was 2,045,700 ounces.
The geology of this district is covered in the California Gold Production Summary article.
PLACERS IN TERTIARY GRAVELS
The placers in Tertiary channel gravels in Calaveras County have been productive at Mokelumne Hill in T. 5 N., R. 11 E., at San Andreas in T. 4 N., R. 12 E., and near Murphys in T. 3 N., R. 14 E.
Two of the productive Tertiary channel systems - the Tertiary Calaveras River and the somewhat younger Cataract or Table Mountain channel - pass through the county (Julihn and Horton, 1938, p. 22). These deposits first were worked by both drift and hydraulic methods, but legislation curtailed hydraulicking, and drift mining was then used exclusively.
Production before 1880 is unrecorded but probably was large. Records of the placer gold mined from these deposits since 1880 are incomplete because placer production from all sources was grouped in the annual reports. Incomplete records of individual drift mines total 106,000 ounces (Julihn and Horton, 1938, p. 33-75); therefore this total may be considered a minimum production from the Tertiary gravels.
