Deep in Danby Workers Mine the World''s Largest Underground ...
The former Vermont Marble Co.''s Imperial Danby Quarry is the world''s largest underground marble quarry—a 28acre cavern that has been in operation since 1906. The 1mile long tunnel snakes down some 600 feet into the bowels of the mountain, which is part of what is known as the Shelburne Formation — a 450millionyearold marble deposit ...