Home Annual Meeting > Fieldtrips


GRC Fieldtrips

Friday, October 12 - Sunday, October 14   

Long Valley Caldera

Sunday, October 14

Steamboat Springs Geothermal Field

Monday, October 15 - Wednesday, October 17

Geothermal Direct Use Tours of the Peppermill Resort

Thursday, October 18

Searching for Blind Geothermal Systems Utilizing Play Fairway Analysis, Western Nevada

Please note: Fieldtrip itineraries are subject to change. Full schedules will be made available below. Check back for updates.

All GRC off-site Field Trips meet in the Tuscany Foyer of the Peppermill Resort Spa & Casino. Check-in is required 30 minutes before departure. Please arrive early to check-in and get continental breakfast (when applicable).


Long Valley Caldera Long Valley Caldera Fieldtrip 2015

Friday, October 12 - Sunday, October 14

Depart noon on Friday, returning to the Peppermill by 5:30pm on Sunday  

Cost: $625
Led by: Gene Suemnicht and Duncan Foley.

Join us for a field trip to one of the best-studied Quaternary calderas in the world. The tour route follows the Walker Lane on the eastern side of the Sierra Nevada passing the Steamboat Springs geothermal field and thermal areas at Bridgeport and Fales Hot Springs.

The field trip will highlight the volcanic history of Long Valley caldera and the evolution of the geothermal system including spectacular overviews of the caldera and the eastern Sierra crest.

Tour stops will include the geothermal power plants at Casa Diablo, surface manifestations at Hot Creek, the ultradeep DOE magma drilling site within the caldera’s resurgent dome and a hike to the Inyo Craters.

The return trip to Reno will stop at the Mono Craters, Mono Lake and the epithermal mineral system at the historic ghost town of Bodie.

A field trip guide will cover technical information about the Long Valley region and participants are invited to join the discussion of the exploration history of Long Valley during the GRC Conceptual Modeling workshop on Friday morning. 

Field trip guides Gene Suemnicht of EGS Inc. and Duncan Foley of Pacific Lutheran University will provide interpretive commentary during the trip.

Included in the cost of the fieldtrip is transportion, continental breakfast and lunch on Saturday and Sunday, two nights lodging (double occupancy required) at the Mammoth Mountain Inn and all the eastern Sierra beauty you can stand!

Limited seating, please register early!


Steamboat Springs Geothermal FieldGRC Nevada Fieldtrip 2012

Sunday, October 14

Depart 9:00am, returning to the Peppermill by 12:00pm

Cost: $60
Led by: Matthew Sophy

Ormat’s Steamboat Geothermal Power Plant Complex, located just south of the city of Reno, currently produces enough renewable energy to meet the residential electrical needs of the city of Reno.

Located in Washoe County, Nevada, Steamboat consists of six power plants with a combined generating capacity of 73 MW; Steamboat 2/3, Burdette (Galena 1), Steamboat Hills, Galena 2, and Galena 3 . Except for Steamboat Hills, which utilizes a single flash system, all of the projects in the Steamboat complex utilize a binary system.

The electricity generated by the complex is sold to NV Energy and Southern California Public Power Authority under separate long-term power purchase agreements.

The tour will highlight the unique geology associated with the Steamboat surface  manifestations and reservoir as well the Steamboat geothermal power plant complex. This will include the state-of-the-art Galena III recuperated integrated two-level unit and Steamboat Hills single flash unit. Knowledgeable field trip guides will provide expert commentary during the trip.

Cost includes transportation only. Make sure you have breakfast before you leave!

Limited seating, please register early!


Geothermal Direct Use Tours GRC Peppermill Fieldtrip 2012
of the Peppermill Resort

“The only resort in the United States whose heating source is totally provided from geothermal energy produced on the immediate property.”

Free to Registrants - Compliments of GRC & Peppermill Resort Spa Casino

Monday, October 15 - Wednesday, October 17

  • Monday: 12:30 – 1:00 pm, 3:10 – 3:40 pm
  • Tuesday: 9:40 – 10:10am, 12:30 – 1:00 pm, 3:10 – 3:40 pm
  • Wednesday: 9:40 – 10:10am, 12:30 – 1:00 pm

Tours will depart from and return to the Tuscany Foyer. (Limited to 30 participants per tour)

Located at the north end of the Moana Hot Springs thermal anomaly, the Peppermill's pools, hot tubs, domestic water for showers and mechanical systems, generate all of their heating energy from their geothermal operation 24 hours a day seven days a week.

In addition to pumping the naturally heated water from the ground, the resort has also installed a reinjection well that returns the geothermal fluids back underground, to be reheated by the volcanic energy after it has heated the property. 

The tour will highlight the geothermal wells and engineering facilities. Our knowledgeable guides will provide an interpretive commentary during the trip, and you won't even need to leave the hotel. 

Sign-ups for the tour will be available at the GRC registration desk.

History of Geothermal Development at the Peppermill Resort Casino

Since the early 1980s, the Peppermill has used the resource's low-temperature thermal waters as the primary heat source for the North Wing and an exterior pool. Initially, two shallow wells – the Peppermill #1 and #2 – produced about 127°F (53°C) water from Neogene epiclastic sediments of the informally named, lithologically heterogeneous Sandstone of Hunter Creek at the total rate of approximately 100 gallons per minute (gpm) (6.3 liters per second) from depths between 328 ft. (100 m) to 934 ft. (285 m).

Injection of the spent geothermal fluids into the producing formation was not required by the regulatory agency, allowing the surface disposal of the geothermal waters. However, the Nevada Department of Environmental Protection terminated the Peppermill's permit for surface disposal in 1988, which necessitated the drilling of an injection well. The Peppermill #4 well was drilled from December 1988 to July 1989 to a total depth of 3,307 ft. (1,008 m) in andesites of the Tertiary Kate Peak Fm. Sixteen inch (40.6 cm) surface casing was set and cemented at 220 ft. (67 m), 10¾ inch (27.3 cm) intermediate casing set and cemented at 1,220 ft. (372 m), and 7 inch (17.8 cm) liner hung from 1,220 ft. (372 m) to 3,307 ft. (1,008 m) with perforations from 2,600 ft. (792 m) to total depth. It was flow tested using air-lift from approximately 180 ft. (55 m). Results indicated the well was capable of producing 160°F (71°C) water at the rate of 170 gpm (10.7 liters per second) under artesian conditions. It was completed as the disposal well, with the injection of the spent geothermal fluids into permeable volcanic andesites below 2,620 ft. (799 m).

In 2007, the Peppermill began construction on a large expansion of their facility, adding over 500,000 square feet (46,452 square meters) of finished space and a new centralized power plant that would become an integral component of the geothermal master plan. As part of this expansion, the Peppermill furthered the use of the existing shallow wells by adding a heat exchanger and heating the new exterior pools, spas, and domestic hot water for the new Tuscan Tower. In 2009, as a result of significant energy savings from the limited geothermal development, the Peppermill elected to expand the capacity of its geothermal heating system, making it the primary heat source for the entire campus.

The Peppermill #8 well was drilled in August-September 2009, reaching total depth of 4,421 ft. (1,348 m) in andesites of the Kate Peak Fm. It was completed as a production well with 13⅜ inch (34.0 cm) surface casing set and cemented at 1,509 ft. (460 m) and a 9⅝ inch (24.5 cm) perforated liner hung from 1,415 ft. (432 m) to 4,421 ft. (1,348 m). The well was tested flowing 1,185 gpm (74.8 liters per second) of 175°F (79°C) water from highly fractured altered andesite, exceeding the required fluid temperature and flow rate. This volume of new production, however, required drilling an additional well to supplement the Peppermill's injection capacity. Because the second well was designed as an injection well it had to meet more stringent design criteria. The Peppermill #9 was drilled in December 2009 to January 2010 to total depth of 3,900 ft. (1,189 m) in the Kate Peak andesites. Twenty inch (50.8 cm) surface casing was set and cemented at 483 ft. (147 m), 13⅜ inch (34.0 cm) intermediate casing set and cemented at 2,202 ft. (671 m), and 9⅝ inch (24.5 cm) perforated liner hung from 2,091 ft. (637 m) to 3,896 ft. (1,188 m). The liner was perforated between 2,361 ft. (720 m) and 3,859 ft. (1,176 m). The well was tested flowing 345 gpm (21.8 liters per second) of 153°F (67°C) water from highly fractured altered andesite. An injection rate of 708 gpm (44.7 liters per second) at 246 pounds per square inch (psi) (1.69 MPa) was achieved during injection testing. Both vertical wells were extensively logged, including image logs acquired in the Peppermill #8.

The primary challenge encountered during the drilling process was from sloughing clayey formations in highly altered zones. Simple gel-based mud was used in order to avoid contamination of the aquifer; no stabilization additives were added to the drilling fluids. It was occasionally necessary to “wait-out” the running formation and allow it to reach an angle of repose before drilling ahead. The surface and intermediate drilling presented few problems.


Searching for Blind Geothermal Systems
Utilizing Play Fairway Analysis, Western Nevada

Thursday, October 18

Depart at 7:00am, returning to the Peppermill by 7-8:00pm  

Cost: $475
Led by: Jim Faulds, Jason Craig, and Nick Hinz (University of Nevada, Reno)

This trip will visit southern Gabbs Valley in western Nevada, where a blind geothermal system was recently discovered through application of the play fairway analysis. The geothermal play fairway concept involves integration of multiple parameters indicative of geothermal activity as a means of identifying promising areas for new development.

On this trip, we will review the play fairway methodology applied to Nevada, discuss a new geothermal potential map for the region, and assess the geologic, geophysical, and geochemical evidence for a blind geothermal system in southern Gabbs Valley, including positive results from recently completed temperature-gradient drilling.

Cost includes transportation, continental breakfast, lunch and dinner.

Limited seating, please register early!


Please note: Fieldtrip itineraries are subject to change. Full schedules will be made available above. Check back for updates.