A Colorado Department of Transportation contractor will close the south end of Colorado Highway 3 this morning to begin a three-month project to control rocks falling from the unstable sandstone cliffs that border the highway.
The work will entail all-day, two-way closures of Highway 3 from Sawmill Road to its junction with U.S. Highways 550/160, near the Walmart intersection. The work is expected to last until mid-November.
Access to businesses on Sawmill Road and to Animas Surgical Hospital, medical offices and condominiums on Rivergate Lane will be from the north, by Santa Rita Drive and East Eighth Avenue.
Crews from TK Construction in Grand Junction will remove loose rock and then install a new style of wire mesh to slow the descent of rocks falling from the cliffs – part sandstone, part Mancos shale – and channel debris to an area behind concrete barriers along the highway.
Scaling of the cliffs, as it’s called, will be done with pry bars, small explosive charges, air bags and grout under pressure.
Steel posts 6 to 12 feet long then will be anchored at different angles into the hillside to accommodate the mesh, CDOT spokeswoman Nancy Shanks said Wednesday.
The mesh will consist of 8-inch squares of half-inch steel joined to form a curtain 1,600 feet long and 30 feet high to hang from the posts.
A team from CDOT, Colorado School of Mines, the consulting firm Yeh and Associates, and the National Research Council’s transportation board designed the new wire netting, Shanks said.
Unlike the mesh that stabilizes a shaky hillside on Red Mountain Pass, the Highway 3 curtain won’t lie on the ground. Instead, it will hang away from the cliff.
Shanks said the mesh is designed to intercept falling rocks and boulders and guide their path to a catch area at highway level.
The sections of concrete barrier, 34 inches tall, will be set to one side periodically in order to haul away fallen rocks, Shanks said. The removed rock belongs to the contractor, she said.
The Carbon Junction Trailhead will remain available for the duration of the project, but parking will not be allowed, Shanks said. Trail users can park at the Big Canyon Trailhead to the south, opposite Dominguez Drive, the entrance to Walmart.
A temporary roadside path will be created between the trailheads, Shanks said.