Founded in 1851, South Spring Hill Mine worked continuously until 1893. Keystone Company purchased it in 1920 and connected it to its operations. The mine closed in 1942. It contained three shafts: South Spring Hill at 1200 feet, Tallisman at 600 feet, and Medean at 600 feet deep. From 1888 to 1902, it produced $1,092,472. Amador.