The Johnnie district is in the extreme southeast part of Nye County (lat 36"26' N., long 116"04' E.).
Organized in 1890, the district had a recorded production of $382,681 by 1913, although Krai (1951, p. 86) estimated that more than $1 million in ore was produced from 1910 through 1913. Nolan (1936b, p. 69) estimated $500,000 worth of gold was produced before 1904, and 24,653 ounces of gold was produced during 1908-32. Total gold production through 1959 was about 40,000 ounces, mostly from the Johnnie mine.
The bedrock is the Prospect Mountain Quartzite of Cambrian age (Krai, 1951, p. 86-87). The beds are predominantly quartzite, but some conglomerate, shale, and limestone units are also present. Well-defined gold-bearing quartz veins cut these sedimentary rocks. Gold and galena are the chief economic minerals.
The Lodi (Granite, Marble, Quartz Mountains) district is in northwest Nye County (T. 13 W., R. 36 E.). In 1863 the area was part of the original Mammoth district, but in 1874, the Lodi district was formed from the part of the Mammoth that included the Lodi Hills.
Gold is a byproduct of silver and lead ores which have been the mainstay of the district. Tungsten and some talc also have been produced. The most important mines in the district are the Illinois and the San Rafael (Krai, 1951, p. 94-96).
Available production data are not complete and give combined output only; therefore, the amount of gold represented can only be inferred. Couch and Carpenter (1943, p. 113) reported a total of $809,905 in silver, gold, lead, and copper from 1866 through 1940. The total for 1932 through 1959 was 1,079 ounces of gold (U.S. Bureau of Mines, 1933-66).
Krai (1951, p. 93-94) briefly summarized the geology of the district. The rocks of the district are deformed limestone and dolomite of Triassic age intruded by granodiorite of Jurassic or Cretaceous age. The major ore deposits of lead and silver were deposited in the deformed and ruptured limestone and dolomite during the closing stages of the intrusion. In Tertiary time, lava flows covered the area. These were succeeded by andesite intrusions after which considerable faulting took place. A second period of mineralization filled the fault fissures.
Manhattan, at the south end of the Toquima Range about 35 miles north of Tonopah, is a gold district, silver being produced as a byproduct. Although mining had been done in the Toquima Range since 1865, it was not until 1905 that gold was found in the Manhattan area in sufficient quantity and grade to precipitate a rush. By 1906 there were 3,000 people in the general area (Ferguson, 1924, p. 8). The next few years were marked by numerous fraudulent promotion schemes that gave the district widespread notoriety and seriously delayed its development. But placer mining flourished and reached its peak by 1912, after which there was a steady annual decline (Ferguson, 1924, p. 8-9). Lode mining became important after 1908.
From 1906 through 1921 the district produced 136,514 ounces of lode gold and 58,686 ounces of placer gold (Ferguson, 1924, p. 9) ; through 1959, the total was 280,022 ounces of lode gold and 206,340 ounces of placer gold.
The bedrock of the district is composed of quartzite, limestone, and schist of the Gold Hill Formation of Cambrian age and chert, slate, quartzite, and limestone of the Palmetto Formation of Ordovician age (Ferguson and Cathcart, 1954). Small patches of granite, of Jurassic age, are exposed locally. Tertiary lavas, tuffs, and intrusive bodies comprise the bedrock in the northern part of the district. The Gold Hill Formation is thrust over the Palmetto Formation, and the productive deposits are in the hanging wall of this thrust fault, in limestones and quartzose schist of the Gold Hill Formation. The ore bodies in the limestone show a complex assemblage of metals, including pyrite, stibnite, realgar, orpiment, cinnabar, and free gold in a gangue of calcite, quartz, fluorite, sericite, leverrier-ite, and sparse adularia. Ore bodies in the quartzose schist have been more productive and consist of networks of small quartz-adularia veins, carrying pyrite and free gold.
The placer gold has come from deep gravels in Manhattan Gulch.
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