Geothermal/Geology and Minerals
Geothermal Geology and Minerals
Geology and Minerals
Present, Potentially Affected
- Antelope Valley Neset (AVS - Neset 345 kV Transmission Line Project)
- BLM-NV-WN-ES-08-01-1310, NV-020-08-01 (Blue Mountain Geothermal Well Field and Power Plant EA)
- Barren Ridge Renewable Transmission (Barren Ridge Renewable Transmission Project Environmental Impact Statement)
- Big Eddy-Knight (Big Eddy-Knight Transmission Project Environmental Impact Statement)
- Boardman to Hemingway (Environmental Impact Statement and Land Use Plan Amendments for the Boardman to Hemingway Transmission Line Project)
- CA-96062042 (Fourmile Hill Geothermal Development Project Environmental Impact Statement (EIS) / Environmental Impact Report (EIR) for Geothermal/Power Plant, Geothermal/Well Field, Geothermal/Transmission)
- Central Ferry Lower Monumental (Central Ferry-Lower Monumental 500-kilovolt Transmission Line Project)
- DOE-EA-1733 (Calpine Enhanced Geothermal Systems Project EA at Geysers Geothermal Area for Geothermal/Well Field)
- DOE-EA-1759 (EA for Geothermal/Exploration at Southwest Alaska Regional Geothermal Energy Project Naknek, Alaska)
- DOI-BLM-CA-ES-2013-002+1793-EIS (Casa Diablo IV Geothermal Development Project EIS at Long Valley Caldera Geothermal Area for Geothermal/Power Plant)
- DOI-BLM-NV-B020-2011-0026-EA (Clayton Valley Geothermal Exploration Project EA for Drilling and Well Testing)
- DOI-BLM-NV-B020-2012-0214-EA (Silver Peak Area Geothermal Exploration Project EA for Drilling and Well Testing for Geothermal/Exploration)
- DOI-BLM-NV-C010-2010-0006-EA (Gabbs Valley and Dead Horse Wells Geothermal Exploration Projects EA for Geothermal/Exploration)
- DOI-BLM-NV-C010-2010-0010-EA (EA at Coyote Canyon and Dixie Meadows for Geothermal/Exploration Drilling and Well Testing)
- DOI-BLM-NV-C010-2010-0016-EA (EA for Airborne Electromagnetic Survey at Patua Geothermal Project for Geothermal/Well Field, Geothermal/Power Plant)
- DOI-BLM-NV-C010-2011-0001-EA (Coyote Canyon Utilization Project EA for TGP for Geothermal/Power Plant)
- DOI-BLM-NV-C010-2011-0516-EA (EA for Thermal Gradient Holes at Dixie Meadows Geothermal Exploration Project for Geothermal/Exploration, Geothermal/Well Field)
- DOI-BLM-NV-C010-2012-0029-EA (Tungsten Mountain Geothermal Exploration Project EA for Geothermal/Well Field Drilling and Well Testing)
- DOI-BLM-NV-C010-2012-0050-EA (Wild Rose Geothermal Project EA for Geothermal/Well Field, Geothermal/Power Plant)
- DOI-BLM-NV-C010-2012-0051-EA (Coyote Canyon South Geothermal Exploration Project EA for Geothermal/Exploration)
- DOI-BLM-NV-CC-ES-11-10-1793 (Salt Wells Geothermal Energy Projects EIS for Geothermal/Power Plant Development Drilling)
- DOI-BLM-NV-CO10-2011-0501-EA (EA for Phase II Production Wells and Thermal Gradient Holes at Patua Geothermal Project for Geothermal/Well Field)
- DOI-BLM-NV-W010-2011-0001-EA (EA of the Leach Hot Springs Geothermal Exploration Project at Grass Valley Geothermal Area for Geothermal/Exploration, Geothermal/Well Field Drilling and Well Testing)
- DOI-BLM-OR-P000-2011-0003-EA (EA for Newberry Volcano Enhanced Geothermal System (EGS) Demonstration Project for Geothermal/Well Field)
- DOI-BLM-OR-P040-0021-EA (EA for Exploratory Wells at Midnight Point and Mahogany Geothermal Exploration Projects, Glass Buttes, Oregon for Geothermal/Exploration)
- Devers Palo Verde No 2 (EIS/EIR Devers-Palo Verde No. 2 500kV Transmission Line Project)
- EA for Well Field Development at Patua Geothermal Area - DOI-BLM-NV-C010-2011-00016-EA (EA for Phase II of Patua Geothermal Project for Geothermal/Exploration, Geothermal/Well Field)
- Eldorado Ivanpah Transmission Project (EIS/EIR for the Eldorado-Ivanapah Transmission Project)
- Energy Gateway South (Environmental Impact Statement and Land Use Plan Amendments for the Energy Gateway South Transmission Project)
- Gateway West Transmission Line (Environmental Impact Statement for the Gateway West Transmission Line Project)
- Grand Coulee Transmission Line (Grand Coulee's Third Powerplant 500-kilovolt Transmission Line Replacement Project, Preliminary Environmental Assessment)
- LLNV-WO1000-2009-0002-EA (EA for Observation Wells at Jersey Valley II Geothermal Exploration Project)
- McNary-John Day (McNary-John Day Transmission Line Project Environmental Impact Statement)
- Mona to Oquirrh Transmission (Mona to Oquirrh Transmission Corridor Project and Proposed Pony Express Resource Management Plan Amendment)
- NV-020-07-EA-01 (EA for Observation Wells at Jersey Valley Geothermal Exploration Project for Geothermal/Well Field, Geothermal/Exploration)
- NV-063-EA06-098 (Reese River Valley Geothermal Exploration Project Environmental Assessment)
- San Juan Basin EC (San Juan Basin Energy Connect Project Environmental Impact Statement)
- Sigurd Red Butte No2 (Sigurd to Red Butte No. 2 345kV Transmission Project)
- Southline Transmission Line (Environmental Impact Statement for the Southline Transmission Line Project)
- Sun Valley to Morgan Transmission Line (Environmental Impact Statement for the Sun Valley to Morgan Transmission Line Project)
- Sunzia Southwest (SunZia Southwest Transmission Project)
- Tehachapi Renewable Transmission (Environmental Impact Statement for the Tehachapi Renewable Transmission Project)
- Vantage Pomona Heights (Environmental Impact Statement for the Vanage to Pomona Heights 230kV Transmission Line Project)
- West-wide Energy Corridors (West-wide Energy Corridor Programmatic Environmental Impact Statement)
Geologic surveys must be conducted before plant construction can occur. The United States Geological Survey agency houses geological overviews of the United States, however for a specific area evaluation, each state has a geological survey agency to conduct site reviews. This comprehensive survey gathers data on several categories. A few categories are the following:
- Geophysics: This test reveals available resources.
- Physiography: This refers to the terrain’s texture, rock types, geologic structure and history of those structures.
- Lithology: This pertains to an individual rock’s grain size, composition, mass, color and texture.
- Hot Springs: This test gathers water chemistry data.
- Thermal Conductivity: Measurements from several rock units show where the best site to drill is located.
- Temperature: Borehole and gradients are evaluated for their underground temperatures.
- Digital Geologic Mapping: 3D Seismic Mapping indicates where the natural resource is and how much of it exists. Topographical maps show an area’s contouring.
- Phisher location: Finding these small slits in the bedrock shows geologists where wells can best access the natural resource.
- Depth of Bedrock: These are the measurements between boreholes
- Heat flow: This compares the heat transfer between test wells.
- Seismic Risk: Fault line placement, phishers and bedrock types determine how susceptible an area is to earthquakes.
Geology and Minerals Impacts & Mitigation
Drilling activities pose risks above and below the surface level. Mitigating these impacts can elongate reservoir access and reliability.
Enhanced Geothermal Systems (EGS): The increased number of wells for injection and production increases the underground resources impacted. This also increases the probability of agitating existing minerals available for future mining.
To mitigate these impacts, slimhole drilling creates wells that are only 4-6 inches in diameter. Traditional geothermal exploration wells are 8-12 inches in diameter, making slimhole drilling an efficient option for reducing the land needed for well pads. If this alternative is not possible, existing wells not needed for production will remain inactive.
Seismic risk is also present. Fluid reinjection is known to cause subsidence or land surface sinking. To mitigate seismic effects of EGS, seismic monitoring programs equate for structural damage, noise pollution, and current regulations in place.
Industrial and metallic minerals: Sand, Gravel, clay and stone used for construction can agitate industrial and metallic minerals suited for mining. These minerals include, but are not limited to: copper, silver, cobalt, palladium, platinum, rhodium, ruthenium, iridium, and osmium, barite, garnet, bentonite, kaolinite, phosphates, diatomite, borax, gypsum, and potash. To minimize impacts, site assessment can indicate what minerals make up the bedrock. Slimhole drilling also decreases the area of impact.
Factors Affecting Geology and Minerals
Inhibiting factors include the following:
Land closures: Geothermal resources are considered a “fluid mineral resource” by the Bureau of Land Management (BLM) and the Fish and Wildlife Service (FWS) just like oil and gas, therefore, when restrictions on “leasable fluid minerals” exist, geothermal exploration and development is not allowed.
Geothermal on mining claims: It is possible to have mining and geothermal exploration occur on the same land simultaneously. Fill materials require a permit for both parties. All outstanding conflicts will be resolved with mining constituents and geothermal personnel via the BLM.