The Old Mill uses the ancient grist mill technology and the power of falling water, a resource as old as time, in a method that remains as effective today as it was in ancient Rome 2,000 years ago. River water flowing over a 24-foot water wheel turns a shaft attached to machinery inside the mill, while underwater cast-iron tub wheels harness the river's flow to turn the heavy millstones. In the grist mill, a pair of giant millstones crush grain between them, with the top stone rotating slowly against the bottom stone to grind corn into meal or wheat into flour. The millstones are French Buhrs, flint granite imported in 1830 from the south of France, and they weigh about 2,300 pounds each. They are only the second set used in the mill's life; the original stones were shipped to the Carolinas, dragged across the Smoky Mountains on a sled, and replaced in 1977 after about 147 years of grinding. The mill's timbers are native Smoky Mountain trees, including hand-hewn hemlock cross beams, heart pine floors, and massive yellow poplar support beams set on river rock pillars, with posts and beams fastened by square handmade nails. Using millstones weighing 2,000 pounds each, the mill can grind about 300 pounds of corn meal in an hour. From 1921 to 1929, its waterwheels also helped generate electricity for nearby homes and businesses, and Pigeon Forge Power & Light charged a flat $1.25 a month regardless of use.