At its height of production, the mine employed hundreds of workers extracting 7,000 tons per month. By 1890, the owners converted the mine to an open pit. At one time, the pit was the largest man-made
hole in the world.
However, in 1895, a major collapse occurred and the mine was closed. The mine is known worldwide for its unique variety and expanse of rocks and minerals, which are included in the
collections of major museums.
Part of the Trainer Collection from Tilly Foster, on loan from the New York State Museum in Albany, is on view at the