Hot springs at Tipton Ranch in Secs. 4,5, T33N, R40E have reported temperatures as high as 85°C (Mariner and others, 1974), although one spring with a temperature of 87°C was sampled in September 2002. There are numerous springs and seeps, some discharging gas, along a N20°E fault that forms the boundary of the Sonoma Range in that area. The spring deposits are predominantly travertine with a trace of siliceous sinter. Most springs are relatively low flow, but the combined discharge from the area likely exceeds 400 L/min. The "best" estimates of the thermal-aquifer temperature are 194-196°C (Mariner and others, 1974), whereas the Na-K-Ca estimate based on 2002 samples is slightly lower at 175 to 192°C. Wollenberg (1974b) reported that slightly anomalous radioactivity (up to 22.5 µR/hr) is present at the springs.
In 1974 Magma Power Co. drilled a geothermal well at Tipton Ranch to a total depth of 919.6 m (3,071 feet). Bottom-hole temperature was logged at 135°C after 10 hours of circulation, with the last 91 m having a gradient of 0.16 C/m (6.5 F/100 feet; Skip Matlick, personal comm.). In September 2002, the well was flowing at the surface through a leak in the casing and water was depositing travertine over the well head and surrounding. Wellhead temperature was 95°C. The well has also previously been called the "Pumpernickel Valley well." Geophysical surveys and temperature-gradient drilling were conducted in late 2005 and early 2006.
As of 2006, Nevada Geothermal Power Inc. and ORMAT Technologies, Inc. have entered into an agreement to construct a binary geothermal power plant at NGP's Pumpernickel Valley project area. Part of this agreement included acquiring a 933.5-acre lease from ORMAT to consolidate NGP's land holdings in the project area. NGP has also acquired an additional 1,920-acre lease from the BLM. Upcoming development work will include drilling up to three 820-foot gradient wells to better define the geothermal resource and then drill a deep production well test to confirm the potential of the geothermal field (Bulletin Geothermal Resources Council, July/October 2006).
Photos
Close up of seep (PV-1) using syringe to sample the discharge (62°C), Pumpernickel Valley. As of 2006, the Hot Springs (Tipton) Ranch area of Pumpernickel Valley has been leased to Nevada Geothermal Power Inc. and ORMAT Technologies Inc. for construction of a binary geothermal power plant.
Sampling PV-2 at Tipton Ranch in Pumpernickel Valley using extension rod, hose and vacuum pump to obtain sample (85°C). As of 2006, the Hot Springs (Tipton) Ranch area of Pumpernickel Valley has been leased to Nevada Geothermal Power Inc. and ORMAT Technologies Inc. for construction of a binary geothermal power plant.
View of several seeps and gas discharge areas at Tipton Ranch in Pumpernickel Valley (PV-2) with Bret Pecoraro on the left. As of 2006, the Hot Springs (Tipton) Ranch area of Pumpernickel Valley has been leased to Nevada Geothermal Power Inc. and ORMAT Technologies Inc. for construction of a binary geothermal power plant.
Photo of PV-7 at Tipton Ranch in Pumpernickel Valley showing sampling tubing (87°C). As of 2006, the Hot Springs (Tipton) Ranch area of Pumpernickel Valley has been leased to Nevada Geothermal Power Inc. and ORMAT Technologies Inc. for construction of a binary geothermal power plant.
Spring PV-10 at Tipton Ranch in Pumpernickel Valley showing filter flask (77°C). As of 2006, the Hot Springs (Tipton) Ranch area of Pumpernickel Valley has been leased to Nevada Geothermal Power Inc. and ORMAT Technologies Inc. for construction of a binary geothermal power plant.
Spring PV-10 at Tipton Ranch in Pumpernickel Valley looking straight down into the spring (77°C). As of 2006, the Hot Springs (Tipton) Ranch area of Pumpernickel Valley has been leased to Nevada Geothermal Power Inc. and ORMAT Technologies Inc. for construction of a binary geothermal power plant.
Tipton Ranch and cooling ponds from the hot spring area, Pumpernickel Valley. As of 2006, the Hot Springs (Tipton) Ranch area of Pumpernickel Valley has been leased to Nevada Geothermal Power Inc. and ORMAT Technologies Inc. for construction of a binary geothermal power plant.
Tipton Ranch geothermal wellhead (95°C) encrusted with travertine, Pumpernickel Valley. As of 2006, the Hot Springs (Tipton) Ranch area of Pumpernickel Valley has been leased to Nevada Geothermal Power Inc. and ORMAT Technologies Inc. for construction of a binary geothermal power plant.
Tipton Ranch geothermal wellhead (95°C) encrusted with travertine, Pumpernickel Valley. As of 2006, the Hot Springs (Tipton) Ranch area of Pumpernickel Valley has been leased to Nevada Geothermal Power Inc. and ORMAT Technologies Inc. for construction of a binary geothermal power plant.
Airphoto