By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
The first gold discovery in Nevada was in Lyon County in 1849 in Gold Canyon in the Silver City district. This discovery sparked the discovery of the Comstock Lode, in Storey County, 10 years later.
Lyon County is on the west edge of the Great Basin; the Sierra Nevada is immediately to the west. Mining districts are in the narrow, north-trending mountain ranges, typical of the Great Basin province. The most important gold districts are Silver City, Como, and Wilson. The major copper district of Yerington has not produced significant quantities of gold and is therefore not included in this report.
Total gold production for the county from 1903 through 1959 was 254,722 ounces.
The Como (Palmyra, Indian Springs) district is 10 miles southeast of Dayton. Quartz veins were discovered in the early 1860's and, with the Comstock fever still raging, people nocked to this new area, and a town was built before the deposits were properly evaluated (Stoddard and Carpenter, 1950, p. 76). For the next 50 years there Was no significant production from the district. Several attempts were made in 1916, 1929, and in more recent years to mine the low-grade ores, but none could be considered an unqualified success.
The Como mines produced ore valued at $212,698 through 1936 (Stoddard and Carpenter, 1950, p. 77). The Hully and Logan mine produced a total of $76,995 worth of ore from 1900 to 1940, and the Star of the West mine produced $1,118 in 1939. These data are admittedly incomplete. Though gold was the principal commodity, the amount of gold included in these totals is not known; however, 10,000 to 15,000 ounces seems to be a reasonable assumption.
The rocks of the district are Tertiary volcanics, primarily andesite, several thousands of feet thick (Stoddard and Carpenter, 1950, p. 76). Quartz veins, striking east, contain gold, silver, and small amounts of copper in a quartz gangue.
SILVER CITY DISTRICT
The Silver City district is in the western tip of Lyon County, in T. 16 N., R. 21 E.
The lode mines of this district are in the southern extension of the mineralized area of the Comstock Lode district. In addition to the lode mining of the district, there have been numerous placer operations which date back to the original discoveries.
The history of the Silver City district is intimately intertwined with that of the Comstock Lode district and is a vivid and brawling episode in the development of the West. In 1849 gold was first found in Nevada in what was later to be the Silver City district by a party of California-bound Mormons who happened to pan the gravels in Gold Canyon. For the next 10 years the placers were worked, and as they were worked out, the miners searched the hills for gold-bearing veins. These searches led to the discoveries near Silver City and later to the main Comstock Lode itself at Gold Hill and Ophir Ravine.
The Silver City district was always in the shadow of the great Comstock Lode, and although it was a steady producer, it never achieved the status of its neighbor. Gianella (1936, p. 18) stated that the total production of the district is indeterminable because so much has been included with the Comstock data. Couch and Carpenter (1943, p. 93-94) recorded a total mineral production from 1871 through 1940 of $12,740,785, but the amount of this apportioned to gold is not known.
Placer production data for more recent years is available. Vanderburg (1936a, p. 112) listed a production of 14,625 ounces of placer gold from 1920 to 1923. The largest reported placer production for the district was from 1941 to 1943 when $1,115,752 in bullion was mined (Stoddard and Carpenter, 1950, p. 81). In this operation, the largest dragline and floating washer plant on record was used. Total recorded gold production for the district through 1959 was about 190,000 ounces.
The oldest rocks in the district are limestone, shale, and schist of possible Triassic age. These rocks have been folded and deformed and are unconformably overlain by Triassic metavolcanics about 1,000 feet thick. Quartz monzonite, similar to that in the Sierra Nevada, intruded the Triassic rocks in Late Jurassic time. A thick series of volcanic rocksandesite, rhyolite, basalt, breccia, and tuff of early Tertiary age overlies the older rocks. During late Miocene time or post-Miocene time, the Tertiary rocks were faulted and mineralized (Gianella, 1936, p. 32-35).
The early Tertiary rocks are overlain by a series of Pliocene (?) and Pleistocene lavas, breccias, and agglomerates. Later movement occurred along the early faults, some of it in comparatively recent time.
The important veins of the district are in fissures and faults. The principal vein, the Silver City vein, occupies a fault closely parallel to Gold Canyon and is a southern branch of the Comstock Lode (Gianella, 1936, p. 88-89). The gangue of the Silver City vein is quartz and calcite. The ore minerals are pyrite, gold, silver, electrum, argentite, and minor chalcopyrite. The sulfides make up only 1 or 2 percent of the veinfillings (Gianella, 1936, p. 92).
The Wilson (Pine Grove, Rockland, Cambridge) district is in south-central Lyon County in parts of Tps. 9 and 10 N., Rs. 25 and 26 E. This district was in Mineral County until 1933, when a boundary change put it in Lyon County.
Gold was discovered in some outcrops in this area in 1866, and soon afterward the Wilson and the Wheeler mines were producing. The district produced steadily to 1893, and to that time the Wilson mine had produced ore valued at $5 million, and the Wheeler, $3 million (Hill, 1915, p. 136). Hill reported a production from 1902 to 1911 of $142,524 (about 7,000 ounces) in gold from the district. The Rockland mine produced $263,071 worth of ore during 1915-16 (Stoddard and Carpenter, 1950, p. 96). From 1917 through 1959 the district was idle except for a brief period of small-scale activity in the late 1930's and early 1940's. Total gold production through 1959 was about 408,000 ounces.
The district is underlain by quartz monzonite, very similar to that in the Sierra Nevada batholith (Hill, 1915, p. 134, 135). The ore deposits are in a sheared zone that crosses the quartz monzonite in a northwesterly direction. The quartz monzonite is also cut by at least one granite porphyry dike and is overlain by a series of pink and gray rhyolite flows.
The ore consists of lenses of quartz and pyrite in the crushed zone of monzonite just south of the major fault. The valuable constituents are gold and silver, and the highest grade ore is in the oxidized zone near the surface.