1 Underhill Road, Grafton, NH, New Hampshire 03240. The Ruggles Mine Co INC, in Grafton N.H., with over 235 acres, is part of the Littleton Formation and has a rich mining and geological history. It is the oldest and largest mine of its kind in the United States. Minerals such as Mica, Feldspar, Beryl, and Uranium were mined at Ruggles for 175 years. For the last 50 years it has been a hugely successful tourist attraction. The sellers are retiring and offering this unique and very lucrative opportunity.