MOTHER LODE DISTRICT
The Mother Lode district is delineated by a chain of about 40 mines that crosses Tuolumne County from northwest to southeast from a point just west of Tuttletown in the north to the headwaters of Moccasin Creek in the south, where the lode enters Mariposa County.
Probably the first major property to be developed in this district was the Harvard mine, discovered in 1850 (Julihn and Horton, 1940, p. 30). In 1852 the Dutch claim was located. The claim was later consolidated with the Sweeney and App-Heslep mines, and this combination became the most productive property in the district with an output of about $9 million in gold to 1928 (Julihn and Horton, 1940, p. 20). Another important group of mines, first operated in the 1860's, was the Golden Rule (Julihn and Horton, 1940, p. 42). The Mother Lode mines developed slowly, but as they were deepened, higher grade ore was found and their production increased. Probably the most active period was between 1890 and 1920 when the Rawhide, Harvard, Dutch-App, and Eagle-Shawmut were at their peaks of activity. After World War I, there was a long period of idleness which was ended by the increased price of gold in 1934. The mines were pumped dry and retimbered, and a short period of prosperity returned to the district. During World War II the mines were closed again, and in the postwar period resumption of mining was discouraged by the low grade of the ore and the constantly increasing costs made even higher by the great depths of the mines.
The Mother Lode district in Tuolumne County is credited with $4,310,000 in gold before 1899 (Julihn and Horton, 1940, p. 18). The six largest mines produced a total of $29,750,000 in gold to 1928, and from 1933 through 1959 the Mother Lode produced 86,112 ounces of lode gold and 41,524 ounces of placer gold. The placer production is probably from Tertiary gravels near Jamestown and no doubt should have been credited to that district rather than the Mother Lode. The minimum total production for the district is about 1,550,000 ounces.
POCKET BELT DISTRICT
The Pocket Belt district, 5 to 6 miles wide, is between the Stanislaus River and the Jamestown-Sonora area. This district is known for the extreme richness of small veins that produced minor fortunes in a very short time with small investments. Perhaps the best known of these mines was the Bonanza, located in 1851, which in a single week produced about $300,000 worth of gold. The Pocket Belt has been noted for spectacular short-term operations; thus it exerts a persistent lure, and sporadic activity will probably continue indefinitely.
Production of the district was about $5V2 million (267,000 ounces) (Julihn and Horton, 1940, p. 60). Bedrock is the Calaveras Formation, which has been fractured and laced with seams of quartz and calcite. Locally, where these seams swell, there are concentrations of coarse gold. Some of the gold is crystallized, and in some places it is accompanied by petzite, calaverite, and other tellurides. The seams or pockets are noted for their discontinuity (Julihn and Horton, 1940, p. 60).
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