By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
Mohave County, in the northwestern corner of Arizona, ranks second among the gold-producing counties of the State, with a total of about 2,461,000 ounces through 1959. More than half of this total came from lode mines of the San Francisco district. Three other districts have produced more than 10,000 ounces: Wallapai, Weaver, and Gold Basin. All these districts are in the west-central part of the county, an area of mountain ranges and valleys that trend north-northwest.
GOLD BASIN DISTRICT
The Gold Basin (Salt Springs) district is in the eastern part of the White Hills west of Hualpai Wash, 40 miles north of Hackberry and 60 miles north of Kingman.
Gold-bearing veins were discovered in the early 1870's, but their development was inhibited by the remoteness of the area and scarcity of fuel and water (Schrader, 1909, p. 118-127). Before 1900, however, the district yielded gold ore worth between $50,000 and $100,000, most of which came from the Eldorado mine. Production continued to 1920 on a small scale and a period of inactivity from 1920 to 1932 followed. A few mines were reopened from 1932 to 1942, but the district was dormant from 1943 to 1959. Total minimum gold production of the district was about 15,000 ounces, most of which was from lode mines.
The ore deposits occur in veins in Precambrian granite and schist. The gold is associated with lead or copper ores that contain pyrite, chalcopyrite, galena, molybdenite, and wolframite. The oxidized parts of the veins contain limonite, malachite, cerussite, and vanadinite (Schrader, 1909, p. 119).
SAN FRANCISCO DISTRICT
The San Francisco district is near the south end of the Black Mountains about 29 miles by road southwest of Kingman. It includes both the Oatman and the Katherine camps; Gold Road and Union Pass are local names applied to parts of the district. Gold is the principal valuable metal in the ore deposits of this district.
Soldiers from Camp Mohave on the Colorado River first discovered gold in the Oatman area in 1863 or 1864, in what is now known as the Moss vein (Ransome, 1923, p. 3-8). Other veins with prominent outcrops were discovered soon afterward. Although some rich ore was taken from a pocket close to the surface in the Moss vein in the first 3 or 4 years, most of the development was discouraging and the Oatman camp was inactive for more than 30 years. The earliest locations in the Katherine area were probably made in the early 1880's (Lausen, 1931, p. 13). In 1901 good ore was found in shallow shafts on what is now known as the Tom Reed vein, and in 1902 a stampede to the district occurred when rich ore was found in the outcrops of the Gold Road vein (Ransome, 1923, p. 4; Schrader, 1909, p. 153-154). A high level of activity continued through 1924. The district was revived from 1930 through 1942, and produced a maximum of 48,000 ounces in 1936. From 1943 through 1951, activity was sporadic and was carried out on a small scale, and from 1952 through 1959 no production was reported. The total gold production of the district from 1897 through 1951 was about 2,045,400 ounces.
In general the geology of the district can be described as an uneven terrain of Precambrian rocks overlain unconformably by a thick section of Tertiary volcanic rocks including trachyte, andesite, latite, rhyolite, and basalt flows. The volcanic rocks are the predominant bedrock in the Oatman area, whereas the Precambrian granitic rocks crop out extensively in the Katherine area (Lausen, 1931, p. 22-23). Bodies of quartz monzonite porphyry, sodic granite porphyry, and rhyolite porphyry intruded Precambrian and the lower Tertiary rocks. The rocks were tilted and faulted, and mineral deposits were emplaced in the fractures in late Tertiary time. Most of the deposits are in the Oatman Andesite, although in the Katherine area important deposits are found in faults in the Precambrian granite (Lausen, 1931, p. 101-124).
The veinfilling is a typical epithermal mineral assemblage. Bands of quartz, calcite, and adularia contain clusters and stringers of native gold, hematite, limonite, manganese oxides, fluorite, and a little pyrite, chalcopyrite, and chrysocolla (Lausen, 1931, p. 58-62).
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