The early 1900s saw most of the activity related to the mining of gold disappear in the Black Hills [1]. Mining did not disappear entirely, however. In addition to gold, the Black Hills region is rich in other minerals and into the 1950s led the nation in the production of mica, feldspar, and beryl. Today there are 43 active mines in the state. Gold remains the leading mineral commodity in the state, in terms of value, even though there is only one active mine.
In 2008, Wharf Resources, with a mine located near Lead [2] in the Northern Hills [3], produced 60,665 ounces of gold, with a gross value of $52.9 million. Wharf Resources has been mining in South Dakota since 1982. Today, total mining in the state is estimated to bring in $200 million.
Links:
[1] http://www.moon.com/destinations/mt-rushmore-the-black-hills/discover-mount-rushmore-the-black-hills
[2] http://www.moon.com/destinations/mt-rushmore-the-black-hills/the-northern-hills/lead
[3] http://www.moon.com/destinations/mt-rushmore-the-black-hills/the-northern-hills