Round Mountain District
Other Names: Silver Point, Argentore, Jefferson Canyon, Great Basin
Discovered: 1865, 1901, 1906
Commodities: gold, silver, tungsten, lead, mercury, uranium, arsenic, titanium
The Round Mountain district is on the western slopes of the central Toquima Range and extends from the general area of Willow Creek on the north to Mariposa Canyon on the south. The Silver Point area, 12 miles south of the historic stage station of Hot Spring and about 6 miles southwest of the present town of Round Mountain, was organized in 1865 as the Argentore district and reorganized in 1871 as Silver Point.
Gold discoveries to the north at Round Mountain in 1901-06 led to the organization of the Round Mountain district which included the historic Silver Point area. Schilling (1976) included the adjacent Jefferson Canyon district in the Round Mountain district. The map of Todd and Welton (1866), shows a Great Basin district generally covering the west slope of the Toquima Range in the area now included in the Round Mountain and Jefferson Canyon districts.
Todd and Welton, 1866; Angel, 1881, p. 518; Stuart, 1909, p. 88; Hill, 1912, p. 223; Lincoln, 1923, p. 180; Stoddard, 1932, p. 70; Kral, 1951, p. 144; Beal, 1963, p. 21; La Heist, 1965, p. 66; Bonham, 1976; Schilling, 1976; Kleinhampl and Ziony, 1984, p. 172; Tingley and Berger, 1985, p. 7; Stager and Tingley, 1988, p. 149
Round Mountain Placer District Description
West flank of the Toquima Range, T. 10 N., R. 44 E.
Round Mountain 30-minute quadrangle; Round Mountain #4, U.S. Forest Service, scale 1:31,680.
Ferguson and Cathcart, 1954, Geology of the Round Mountain quadrangle, Nevada, scale 1:125,000.
From Tonopah, 5 miles east on U.S. Highway 6 to junction with State Highway 8a; from there, 49 miles north on State Highway 8a to State Highway 70, which leads 4 miles east to Round Mountain.
The Round Mountain placers, the most productive in the State during the 1900's, are remarkable for the large production yielded for the small area in which they are found. The main placers are on the south and west sides of Round Mountain, a small prominence about 6,800 feet in elevation at the western edge of the Toquima Range. Gravels on the east side of Round Mountain also have yielded some placer gold.
The main placers occur in coarse angular gravels and talus that are about 30 feet deep on the west edge of Round Mountain but thicken to more than 200 feet in the valley about three-quarters of a mile west of Round Mountain. In places, the deposits are considered to be residual, especially on the hillslope, but farther west towards Smoky Valley, the gold was probably transported several hundred feet.
The gold is found throughout the gravels but occurs in highest concentrations on and near bedrock. The size of the gold is generally fine, only as large as a pinhead, but some nuggets also occur. The fineness of the gold is rather low, being only slightly finer than the gold in the adjacent lode deposits, which ranges from 574 to 696. The gold produced by the Round Mountain Gold Dredging Corp. during the period 1950-52 averaged about 630 fine.
The lode and placer deposits at Round Mountain were discovered in 1906. They were first worked by Thomas (Dry Wash) Wil- son, who gained considerable fame for inventing and successfully oper- ating drywashing machines at the Round Mountain placers. The placers have been intensely worked since their discovery and have yielded con- siderable amounts of placer gold almost every year until 1968. Through-out these 62 years, many different mining methods have been used to recover the gold.
The earliest operations consisted chiefly of drywashing shallow gravels on the hillside, especially the claims held by Thomas Wilson adjacent to the Sunnyside lode. The drywash method reportedly recovered only about 70 percent of the placer gold; yet Wilson obtained gold worth $30,000 from these rich gravels in 70 days. Subsequent to initial work with drywashing machines, water was brought in and small-scale sluicing was used to mine some of the gravel. The sluicing led to the construction of a pipeline from Jefferson Canyon, about 3 miles away, and the commencement of hydraulic operations by the Round Mountain Hydraulic Co.
Success of the hydraulic technique on shallow gravels despite the lack of water soon led to the construction of a 14-mile-long pipeline from Jett Canyon across Smoky Valley in the Toiyabe Range, where a better water supply was obtained. From 1906 to 1950 and during the period 1960-68, placer mining in Round Mountain was accomplished by all these methods (sluicing, hydraulicking, and drywashing) at various scales and intensity. The production from these small-scale operations amounted to about 87,000 ounces of the total estimated production for the district.
During the periods 1950-52 and 1958-59, two of the largest and most productive placer operations in the history of dry placer mining in the Southwest worked the Round Mountain gravels. The Round Mountain Gold Dredging Co. worked an area on the west side of Round Mountain (in sees. 19 and 30, T. 10 N., R. 44 E., unsurveyed) three-quarters of a mile west of the town of Round Mountain. The operations produced an open pit about 200 feet or more deep in the gravels, 4,000 feet long from north to south, and 1,800 feet wide from east to west. The first operation, 1950-52, utilized a dragline with scarifying plate located on the edge of the pit to break up the gravels and drop the debris into the pit, where a 7.5-yard electric shovel delivered the gravels to a series of conveyors which, in turn, stacked the gravels for delivery by other conveyors to trommels to the mill.
The mill in which the gravels were processed to remove the gold operated in the same manner as large floating dredges, but was stationary and had no dredge pond. A bucket-line dredge such as that used in Manhattan and Copper Canyon could not be used at Round Mountain because of the thickness of the gravels, large numbers of boulders, steep slope of the bedrock, and porosity of the gravels. The second operation, 1958—59, utilized a remodeled mill and electric shovels to break up the gravels and to strip the overburden, to mine selected areas within the pit. The placer gold production from these operations is estimated at about 145,000 ounces.
The Copper Range Exploration Co. and Ordrich Gold Reserves Co. renewed exploration of both placer and lode areas in the district during the period 1970-72.
The lode deposits on Round Mountain that are the source of the placer gold consist of well-defined veins and numerous closely spaced small veins or stringers containing visible gold in quartz or associated with limonite and minor manganese oxide. These ores are found in a Tertiary welded tuff, formerly thought to be rhyolite.
Engineering and Mining Journal, 1916: Hydraulic operations by Round Mountain Mining Co. ; type of gravels mined ; average value per cubic yard recovered in placer operations of previous season (1915?). 1958b: Reports first phase of renewed large-scale operations at Round Mountain by Morrison-Knudsen Co.; amount of overburden stripped; amount of material to be processed; average value of material.
Ferguson, 1922: History; early production data; value of gravels from to 60 feet; extent of gold-bearing gravels; lithology of gravels; size and fineness of gold recovered; source of placer gold; describes lodes from which placers were derived.
Ferguson and Cathcart, 1954: Text summarizes early study of Round Mountain district (Ferguson, 1922).
Huttl, 1950b: Describes placer-mining techniques at Round Mountain; location, depth, and size of placer gravels.
Krai, 1951: Detailed description of history, geology, lode and placer mines of the district; much information taken from earlier writers. Adds information on large-scale placer mining beginning at that time describes general plan of operation.
Mining and Scientific Press, 1908d: Reports three hydraulic monitors recovering $1,000 per day in placer gold at Round Mountain.
Mining World, 1908: Reports production of $20,000 in fine gold and nuggets from first cleanup by Round Mountain Hydraulic Co. 1950: Describes details of large-scale placer-mining operation; gives illustration of Pit Mining plan; describes talus mined by Round Mountain Dredging Corp. 1951 : Details of mining methods used by Round Mountain Gold Dredging Corp.; details of gold recovery techniques; size and fineness of gold recovered; includes flowsheet showing mining procedures. 1959: Brief note which states that the "Round Mountain Gold Dredging Corp. is doing better in its second placering attempt than it did several years ago. It is now working selected areas by different mining methods."
Packard, 1907: Details of drywashing operations on Sunnyside claim; daily production; depth of gravel washed; compares drywashing at Round Mountain with drywashing at Manhattan. 1908: Describes veins at Sunnyside claim believed to be partial source of placer gold; placer production by Thomas (Dry Wash) Wilson on Sunnyside placer claim; placer-mining developments by Round Mountain Hydraulic Minin
Paher, 1970: Early history of mining activity at Round Mountain; photographs include drywashing activity; hydraulic mining; debris left by placer mining.
Ransome, 1909c: Distribution of gold-bearing gravel; placer-mining operations in 1908; production.
Tonopah Times-Bonanza, 1970: reports the start of evaluation programs at Round Mountain by Copper Range Exploration Co. and Ordrich Gold Reserves Co. Inc. 1972: reports expansion of test program on lode and placer claims in Round Mountain District.
U.S. Bureau of Mines, 1950-52, 1958-60: Describes large placer-mining operations at Round Mountain.
Vanderburg, 1936a: Early placer-mining history and production; extent of placer; depth of gravel; size of debris in gravels; values for distri- bution of gold in gravels; details of different types of small-scale mining methods used in district.