Red Mountain Pass Ends Monday; Crib Wall Work Begins

June 15, 2012 - Southwestern Colorado/CDOT Region 5 - Single-lane traffic and some future night closures.

OURAY COUNTY – The Colorado Department of Transportation will finish the project to reduce rockfall on US 550 on Red Mountain Pass south of Ouray, between the Bear Creek Tunnel and the snow shed (mile marker 91), on this Monday, June 18. On Tuesday, June 19, Midwest Rockfall will start a new project to repair two crib walls (retaining walls) under the southbound lane approximately 1.5 miles north of snow shed. The work will be completed by September 25, 2012.

This second safety improvement project, contracted to Midwest Rockfall, Inc., of Denver for $591,201, involves replacing two retaining walls at mile posts 89.6 and 89.65. The project will include:

  1. Excavation for pipe replacement;
  2. Replacement of pipe and placement of a new inlet;
  3. Installation of a new retaining wall.

TRAVEL IMPACTS: Through September 25, motorists will encounter single-lane, alternating traffic between 7 a.m. and 7 p.m., Monday through Friday. There will be no weekend work. Motorists will also encounter periodic full traffic holds in both directions of up to 15 minutes during work hours (while equipment is in the roadway). Please note, while these traffic holds will be limited to 15 minutes or less, motorists’ actual delays will exceed 15 minutes, as the traffic queues are cleared in each direction. Delay times will vary depending upon traffic volumes.  There will be a maximum of six night closures from 8 p.m. to 6 a.m. (Monday through Thursday nights only) to accommodate drainage pipe installation. Notice will be sent before that occurs.

For information on this project, the public may call Midwest Rockfall, Inc.’s Public Information Manager Filiberto Marquez, at (970) 462-1529. (For information on other CDOT projects statewide, the public may log on to or call 511.) Better yet, sign up for highway updates by going to and choosing the green cell phone icon in the upper right corner. Thank you for going Slow for the Cone Zone!

The completed rockfall project involved the following, between mile posts 88 and 91:

a)    minor rock scaling - rocks were brought down with pry-bars or inflatable bags;

b)    rock stabilization -  crews drilled 1 3/8”-diameter holes (approximately 20 feet apart) down to fracture points, then filled holes with a Poly-Urethane Resin, which acts as a kind of glue;

c)    rock bolting - crews drilled and inserted 10-foot-long steel dowels and 25-foot long steel rock bolts into various locations to provide further stabilization;

d)    rockfall netting - several types of rockfall wire mesh/netting were anchored from above to guide smaller rocks into ditch below.