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| The construction of
the Cumberland Gap Tunnel was a crucial step in the broader goal of restoring
the Cumberland Gap to the way it appeared to the earliest pioneers.On
June 21, 1991, the first rock of what is now the north-bound tunnel was
blasted, beginning this herculean effort.
A pilot tunnel, 10 feet high, 10 feet wide, and 4,100 feet long, revealed several characteristics of the mountain that would pose challenges to the project. It was discovered that the mountain would produce 450 gallons of water every minute, regardless of outside weather conditions. The tunnels would course through occasional rock voids with thick clay infillings. Within limestone formations, caves as high as 85 feet and a "lake" of water 30 feet deep were encountered. |
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| Excavation took place simultaneously from
both sides of the mountain, and met in precise alignment in July 9, 1992.
The project was successfully open to traffic 1,947 days after the initial
blast.
The Cumberland Gap tunnel is actually a set of twin tunnels 4,600 feet in length. Each has two dividing lanes and at he tallest point the tunnels are 30 feet in height. Cross passages located every 300 feet connect the two tunnels and are equipped with fire extinguishers and phones for emergency use. Each tunnel is lined with a thick PVC liner to ensure the tunnels remain dry. High-pressure sodium lights illuminate the tunnels, and 32 large, jet-powered fans keep the air circulating. Sensors collect data on traffic |
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| movement and volume, and this data, along with visual information supplied by in-tunnel cameras, is monitored in the portal building on the Kentucky side of the tunnel. The ground floor of the portal building houses a fully-equipped ambulance, fire truck, and two wreckers. The control room is on the ground floor. |  |
| The Tennesse side portal building has the
same equipment, but no control room.
The Cumberland Gap Tunnel is an engineering marvel. It stands as an example of what can be accomplished through cooperation between federal and state agencies. |
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