CO 133 McClure Pass Rockfall

About the Project

The project will include rock scaling (bringing loose surface material down with pry bars or other equipment) and stabilization; rock excavation and blasting; rockfall wire mesh installation; and construction of a rockfall catchment structure. This project also includes erosion control and localized highway repair at each of the five rockfall sites between mile point (MP) 48 and MP 60.3, and grading at the Placita rock disposal site near the northern base of the pass at MP 47.1.

Project Locations

Approximate timeframes for work at the separate work sites are as follows (weather dependent and subject to change):

May to June:

Firehouse, MP 52.59 - Work will involve rock scaling (bringing loose material down with pry bars and other equipment), additional excavation with a hammer excavator, and draped mesh. (This rockfall site lies between the north and south accesses of Redstone Blvd., both of which will remain open during work at this location.)

June to August:

Gray Cut MP 60.20 and Nettles MP 60.30 Sites - These adjacent sites will receive the same mitigation treatment as the Firehouse site, above. The Nettles site will include 15-foot-long rock dowels and a reinforced shotcrete (sprayed concrete) buttress to retain a large boulder.

Penny Hot Springs MP 55.20 - Work here requires crews to build a gravity wall, a concrete-faced, gravel rock-filled wall, approximately 21-feet tall, 12-feet thick and 425-feet long, to contain rockfall material.

August to October:

Hunter’s Loop Cut, MP 48.00 - This site requires blasting of rock material; the work will involve drilling into rock, initially, followed by blasting, likely over a two- to three-day period in late August or early September. There will be one to two periods of midday blasting each of those days, during which time motorists will be fully stopped in both directions for up to one hour, followed by clearing of traffic in each direction. The public will be notified of these periods of extensive delays for blasting at least one week prior, including messages on project signage. The hillside will be further stabilized with the installation of 25-foot-long rock bolts, heavy-gauge cable mesh and a lighter-gauge draped mesh (hung with the use of a crane).

Late April to October:

Placita Disposal Site, MP 47.1: Trucks will be entering and exiting here, causing intermittent traffic slowing and brief stops

Travel Impacts

• The rockfall mitigation work was completed on schedule, by late October. Motorists may encounter periodic single-lane, alternating travel during daytime hours through November - for ongoing CDOT maintenance work to clear debris from previous mudslides in the area.

For weekly updates on work site location/s and traveler impacts, please see CDOT's traveler information site at www.cotrip.org and choose the Interactive Map link.