By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
Most of the gold came from placers, which produced about 3,123,115 ounces from 1880 to 1959.
During 1903-58, Butte County produced 103,800 ounces of gold from lode mines and 2,332,960 ounces from placers. Although there is no record of gold production before 1880, undoubtedly there was intensive activity.
The major gold-producing districts in the county are Oroville (Quaternary placers), Magalia (Tertiary placers), and Yankee Hill (mostly lode, some Tertiary placers).
The western half of Butte County is covered by alluvial gravels; the eastern half is dominated by the northwest-trending Sierra Nevada composed of granitic batholith and the intruded older metavolcanics and metasediments (O'Brien, 1949, p. 417-433). These older metamorphic rocks are also intruded by serpentine and are covered locally by basalt flows of Miocene and Pliocene age.
The metavolcanics contain gold-bearing quartz veins in the area between Oroville, Cherokee City, and Oregon City. Gold-quartz veins are also present at Magalia.
The Magalia district is in north-central Butte County near the town of Magalia.
Tertiary gravels of the Magalia channel, a minor Tertiary stream, were mined by underground methods in the early days. The Perschbaker, one of the major mines of the district, produced more than $1 million in gold to about 1910 (Lindgren, 1911, p. 92). Later production is not known, but O'Brien (1949, p. 429) noted that the mine had been idle since 1947.
The production of the entire district before 1932 cannot be determined; from 1932 through 1959 it was 15,976 ounces. Adding to this the 50,000 ounces representing the early production of the Persch-baker mine, we arrive at a minimum total of about 66,000 ounces for the district.
The Oroville district is in southern Butte County, along the Feather River.
The Quaternary flood-plain gravels of the Feather River near Oroville yielded a total of 1,964,130 ounces of gold from 1903 to 1959 and therefore made the Oroville district the largest producer of Butte County. In 1898 the first floating bucketline dredge was successfully operated in the district (O'Brien, 1949, p. 420), and by 1905, 35 dredges were mining the Feather River gravels (Lindgren, 1911, p. 90).
Production continued at a high rate until the early 1950's. From 1957 through 1959 only a few ounces per year was reported.
YANKEE HILL DISTRICT
The Yankee Hill district is in T. 21 N., Rs. 4 and 5 E., in central Butte County.
Most of the lode production of Butte County came from this district; however, published details on its history and geology were not found.
From 1929 through 1959 the district produced 34,427 ounces of gold from lode mines and 5,154 ounces from placers. Production before 1910 was about $1,520,000 (57,000 ounces), mostly from the Hearst mine (Lindgren, 1911, p. 84).