By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
Yavapai County, in the central part of Arizona, ranks first in the State in gold production through 1959.
The production by ounces is as follows:
|Prior to 1900||477,703||193,500|
|1900 to 1934||1,934,447||33,204|
|1935 to 1959||1,064,000||40,100|
The Jerome (Verde) district is the largest gold producer, having contributed about 1,565,000 ounces to the total lode production.
Though mineral deposits were known in this area long before the Civil War, the first prospectors were Union soldiers with mining experience from California (Wilson and others, 1934, p. 23). Placers at Rich Hill were discovered in 1862 and those along Hassayampa and Lynx Creeks were discovered in 1863 (Lindgren, 1926, p. 2-5). Silver ore, first discovered in the Big Bug district in 1870, was found at other localities in Yavapai County in the 1870's. Claims were located in the Jerome district in 1876.
The northern part of Yavapai County is in the plateau region, and the southern part is in the mountain region, which consists of a series of short mountain ranges of the fault-block type that trend north-northwest and are separated by broad valleys filled with fluvial and lacustrine deposits. The mountains consist chiefly of Precambrian metamorphic and igneous rocks, which are intruded locally by stocks, plugs, and dikes of granitic rocks of Late Cretaceous or early Tertiary age. Large areas are covered by volcanic rocks of Tertiary and Quaternary age.
The ore deposits, which are in the mountain region, consist of veins and replacement deposits of Precambrian age and veins of Mesozoic or early Tertiary age. Placer deposits have also been important.
AGUA FRIA DISTRICT
The Agua Fria district is southeast of Prescott along the headwaters of the Agua Fria River about 4.5 miles northeast of Mayer. Both gold and silver are byproducts of copper ore.
The Stoddard mine in this district is one of the earliest locations in Arizona but no dates of discovery or location are known (Lindgren, 1926, p. 148). The district was active during World War I and into the early 1920's - probably its period of greatest production. From 1936 through 1957 the mines were operated intermittently. Total gold production through 1959 was about 12,710 ounces.
The rocks exposed in the district are chiefly schists of the Precambrian Yavapai Series, which are intruded by the Precambrian Bradshaw Granite. The Yavapai Series includes many quartz lenses and bodies of fissile quartz porphyry. The Precambrian rocks are capped locally by volcanic flows and tuffs of Tertiary age (Lindgren, 1926, p. 146-147).
The ore deposits are replacement bodies of quartz, pyrite, and chalcopyrite, and tetrahedrite in the schists.
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