Mercur is a historical hard rock mining ghost town in Tooele County, Utah, United States. In 1891, it became the site of the first successful use of the cyanide process of gold extraction in the United States, the dominant metallurgy today. Its elevation above sea level is approximately 2,042 m. The nearby Mercur Gold Mine was re-opened by Barrick Gold in 1985, with mining operations again coming to an end in 1997. The reclamation and restoration project was set to continue up to 2010.