The highest spring temperatures in Elko County (up to 96°C) are reported from Sulphur Hot Springs, in Sec. 11, T31N, R59E in Ruby Valley. They are probably named for their odor of hydrogen sulfide. The springs flow from a roughly circular sinter mound about 457 m in diameter on an alluvial apron near the east side of the Ruby Mountains (Olmsted and others, 1975). The water flows into Stonier Lake. A major basin-and-range normal fault forms the contact between consolidated rocks and unconsolidated deposits at the mountain front (figure). Another fault cuts the alluvial units about half the distance between the mountain front and the hot springs. Eakin and others (1951) suggested that the thermal spring waters probably rise along a fault.
The siliceous spring sinter consists of white- to light-gray, earthy, amorphous silica (probably opal) deposited by both present and ancestral hot springs (Olmsted and others, 1975). This extensive area of sinter suggests a high geothermal reservoir temperature. Mariner and others (1974) analyzed water from one of the hottest overflowing pools and estimated the reservoir temperature at 183- 190°C using the silica-quartz geothermometer; White and others (1983) estimated a temperature of 178ºC. The area of subsurface hot water at Sulphur Hot Springs is roughly circular and covers approximately 5 km2 (figure).
Waring (1965) reported Miller's Hot Springs in T30N, R69E at the northeast end of Franklin Lake. This description probably refers to the Sulphur Hot Springs area. Batzle and others (1976b) reported on telluric profiles of the Ruby Valley Known Geothermal Resource Area, which includes Sulphur Hot Springs. In 1979, Union Oil Company drilled Union Oil Co. Stonier No. 2, a 960 m deep well located in SE ¼ SW¼ Sec 11 T31N R59E (Barton and Purkey, 1993, p. 12).