Black Diamond Mine - Greathouse portal and visitor center

This portal was the original opening into the sand mine. (Closed to public until 2009.)

In the 1920s underground mining for sand began near the deserted Nortonville and Somersville townsites. The Somersville mine supplied sand used in glass making by the Hazel-Atlas Glass Company in Oakland, while the Nortonville mine supplied the Columbia Steel Works with foundry (casting) sand. Competition from Belgian glass and the closing of the steel foundry ended the sand mining by 1949. Altogether, more than 1.8 million tons of sand had been mined.