Lithium exploration in Nevada has drastically increased in the past couple years. Nevada is home to the only operating lithium mine in the United States which is located in Clayton Valley, Esmeralda County. The mine has been in operation since 1967, employs 85 people, and produces lithium carbonate from evaporation ponds which concentrate the lithium.
The following summary statement on lithium brine deposits was taken from USGS Open-File Report 2013-1006:
"Lithium brine deposits are accumulations of saline groundwater that are enriched (200-1,400 mg/l) in dissolved lithium. All producing lithium brine deposits share a number of first-order characteristics: (1) arid climate; (2) closed basin containing a playa or salar; (3) tectonically driving subsidence; (4) associated igneous or geothermal activity; (5) suitable lithium source-rocks; (6) one or more adequate aquifers. Economic brines have lithium concentrations in the range of 200 to 400 milligrams per liter."
As of April 6, 2021 an estimated 8,675 active placer claims, have been located in Nevada, presumably for lithium brine in 18 different hydrographic basins. Typical exploration is completed by drilling and sampling both sediment and brines using "dual wall reverse rotary" or "push-drill" techniques. The rock sample and the solution are assayed for lithium content. Some lithium exploration holes are 3,000 - 4,000 feet deep.