U.S. Route 191 American Mountain Realignment

Mining haul trucks and private vehicles are traveling on separate routes following the construction of a pair of tunnels and a realignment of a segment of U.S. Route 191 that runs through an Arizona mining operation.

Ames constructed the multiplate tunnels that enable loaded mining haul trucks to cross over U.S. Route 191 unimpeded, increasing haul production for the mine operation while maintaining the public highway traffic and light vehicle traffic below.

The project scope included tunnel overexcavation, geostabilization installation, and structural backfill. Ames crews installed the 240-foot structural steel plate tunnels, constructed roadway barriers, installed an area drainage system, and rerouted the highway alignment through the tunnel. Ames self-performed all aspects of this project except for paving and striping.

The most significant challenge was the construction of the 31-foot 10-inch diameter tunnels. Each tunnel ring was comprised of six plates—three plates for the top half and three for the bottom. After setting several bottom halves, the crew would come back to set a top half and bolt the halves together, taking care to maintain the roundness of the pipe as the length progressed.