Keystone Mine, Amador City, Amador County

Founded in 1851 from many claims. One of the most profitable and longest running mines. Joining with South Spring Hill Mine working till 1942. East shaft worked until 1952. Reached a depth of 2680'. Employed 100 men and produced $24,000,000 in gold.

The foundations are located just a few steps south of the south end of the parking lot on the east side of Main Street (Old Highway 49).

The crumbling stone walls are all that remain to mark the site of the Wildman mine's easternmost shaft, known as the Emerson. The Wildman mine, in combination with the Mahoney, is credited with a production of $5 million in gold.