MIDDLESBORO, Ky. (AP) -- Cumberland Gap Tunnel is back to four lanes after the completion of a $1.5 million repair project to replace the rocks under the concrete slab of the road.
The tunnel reopened all lanes Thursday afternoon. Work on the repairs started in January.
The Daily News in Middlesboro reported that the Kentucky Department of Highways officials started the work after concluding that high acid levels in underground streams were deteriorating the limestone rock under the concrete slab.
Workers replaced the limestone with granite rocks. There are also plans for construction of a dam in the low ends of the repair areas. This dam will be built so that the acidic water can be forced into a drainage system.
The tunnel connects Kentucky and Tennessee near Kentucky's border with Virginia.