By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
Pershing County, created in 1919, is the youngest of the 17 counties of Nevada.
The topography of the county, although less rugged than in most of the State, is typical of that of the Great Basin and consists of north-trending mountain ranges separated by dry valleys.
Pershing County has a wide variety of mineral resources, but silver, gold, tungsten, and mercury have been the mainstays. Mining activity in the area now embraced by Pershing County began in 1860 in the Humboldt district. Soon afterward the Star and Buena Vista districts were discovered, and the town of Unionville became the center of mining activity in the county. The first successful smelter in the State was built at Oreana to treat the base-metal ores. Gold placer deposits were discovered in 1881 in American Canyon, Spring Valley, and Dry Gulch, and these were worked successfully for about 10 years. Discoveries at Seven Troughs and Rochester highlight the mining in the county after 1900 (Vanderburg, 1936b, p. 6).
Production from Pershing County is recorded from 1919, when the county was created. Production of individual districts, in the descriptions that follow, includes the years before Pershing County existed, thus there is a considerable discrepancy between district and county totals.
From 1919 through 1958 Pershing County produced 16,233 ounces of placer gold and 162,109 ounces of lode gold, a total of 178,342 ounces.
The Humboldt (Imlay, Eldorado) district, on the north end and west flank of the Humboldt Range, was organized in 1860 as the first district in the area now included in Pershing County. By 1863, Humboldt City had been founded and had a population of 500. The principal mine was the Imlay, from which a considerable but unknown amount of silver ore was shipped. The Star Peak mine yielded $130,000 in silver and gold up to 1935 (Vanderburg, 1936b, p. 17). Early production data for the entire district are lacking, but from 1932 through 1959 the district produced 35,483 ounces of gold.
The deposit at the Imlay mine consists of a gold-and silver-bearing quartz vein that contains a little lead and copper (Vanderburg, 1936b, p. 16). The country rock is shale, quartzite, and limestone, probably Triassic in age. Ransome (1909a, p. 46) stated that the ores of the northern Humboldt Range, called the Star Peak Range, have several common characteristicsâ€”they occur in Triassic rocks; they seem to have a common age, probably Early Cretaceous; and they contain antimony, more silver than gold, and very little lead or zinc.
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