Documented mining in the Tonopah area began as early as 1900. Tonopah was the queen of the silver camps, although most mining in the area closed by 1950.
Anaconda acquired what would become the Hall-Tonopah property in 1955 and explored and developed the deposit until 1980, when Anaconda constructed and began operating the Hall-Tonopah mine. Anaconda operated the molybdenum mine until 1985, when it was closed and sold to Cyprus Minerals.
Cyprus re-opened and operated the property until 1991, when it was again closed and sold. Between 1981 and 1991, 29 million tons of ore was mined at Hall-Tonopah at an average grade of 0.11% moly to produce a total of 53 million pounds of molybdenum.
Equatorial purchased the entire operation and attempted to produce copper from a separate zone east of the molybdenum pit in 2000. The operation was largely unsuccessful because of the unanticipated effect of fluorine in the feed to leach, which killed the microbe leaching agent and reduced recoveries. Equatorial closed the property in 2002, leaving behind infrastructure, buildings and facilities that are serviceable and able to be reused.
Idaho General Mines (now General Moly) gained control of the Hall-Tonopah project in 2007 and re-named the project the Liberty Project with the completion of a pre-feasibility study in 2008. The company published a revised pre-feasibility study on the Liberty project in November 2011.