What do you get with 54 tons of concrete, 3,500 stainless steel bolts, and 35,000 pounds of structural steel? A new way to head toward the surface at Mammoth Cave National Park.
Those building materials went into a new Mammoth Dome tower and stairs, which serves as the connector between the lower-Historic trail and the upper-Historic trail. The shiny new tower replaced a 53-year-old, 65-foot-tall structure that was ready to be replaced. The new tower allows visitors to make the 2-mile-long, 2-hour-long Historic tour a loop route with minimal retracing.
And, along with being a bit broader than the old tower, and offering better views of the dome room, it looks pretty neat, too!
“This was a huge undertaking and a tremendous accomplishment for the park,” says Superintendent Patrick Reed. “We are very pleased with the finished product. It is more than just a stairway; it greatly enhances the visitor’s experience.”
This was not your typical construction project. The building materials were trucked to the cave entrance, hand-carried down 60 steps, loaded on a custom-made “cave wagon,” wheeled through large-to-increasingly-smaller passageways for over a quarter mile, then maneuvered through Crevice Pit (the size of a standard doorway) and lowered 200 feet to the floor of Mammoth Dome.
“Moving the materials was a challenge and terribly time-consuming,” explains Steve Kovar, facility management chief, who oversaw the work. “And, the contractor had to redesign the lower steps to fit the cave walls and overhanging rock, and modify the tower foundation to avoid displacing a 20-foot boulder. Its completion is truly monumental.”
During construction, personnel time averaged 15 people per day, in 10-hour shifts. Before the contractor, Lyca Construction, Inc., of Louisville, Ky., could even start the new construction, the old tower and concrete steps had be to dismantled and removed – up and out through Crevice Pit, wheeled on the cave wagon, and carried up the 60 steps at the entrance. During the four days of demolition in January 2008, the crews worked two 10-hour shifts per day
“Mammoth Dome is an awesome room,” says Mike Adams, chief of interpretation at the park. “The old tower was merely a conveyance. The new tower provides an amazing view of the cave. It will ‘wow’ our visitors. The larger staircase was designed with safety in mind, too. Previously, if we had to carry someone out of the cave, we had to haul a stretcher up the steps with the head or foot extending beyond the handrail. A stretcher will now fit between the rails.”
The $2 million project began January 2008 and was completed April 15, 2008.