State and City Announce Start of Marshall Mesa Coal Fire Mitigation Project and Marshall Mesa Trailhead Project

The Colorado Division of Reclamation Mining and Safety (DRMS) and the City of Boulder Open Space and Mountain Parks (OSMP) announce the upcoming closure of the Marshall Mesa Trailhead and the commencement of earth moving activities for coal mine mitigation work in the area for the Marshall Mesa Coal Fire Mitigation Project.

The closure of the trailhead is expected to occur as soon as Monday, October 21, 2024, and will likely extend for one year as the City also completes extensive trailhead improvements.

DRMS expects the Marshall Mesa Coal Fire Mitigation Project to take four months and will start with the mobilization of equipment, installation of erosion control and perimeter fencing. Significant earth moving activities will likely not start until November.

The coal seam underlying the Marshall Mesa Trailhead contains several areas of hot smoldering coal. Mitigation work will involve excavating the coal seam to a depth of approximately thirty feet below ground surface. Any hot material will be thoroughly blended with cold soil and rock and cooled to below 80oF before being placed back into the excavation. Any unburned coal found in the project area will also be excavated and thoroughly blended to eliminate, to the extent possible, the potential for future ignition.

Excavation of hot materials will not be allowed during windy conditions. All hot work operations will be halted in the event of a Red Flag Warning being issued for the Marshall Mesa area by the United States National Weather Service. Additionally, if sustained on-site surface winds, or frequent gusts exceeding fifteen miles per hour are recorded on site, all hot work activities will be suspended. In the event that hot work activities are halted, any hot or smoldering coal will be immediately covered with a minimum of two feet of cold soil and rock.

Additionally, the project contractor is required to maintain a minimum of 30,000 gallons of water on-site for the duration of any hot work activities. This water is dedicated for fire suppression and will not be used for any other site activity until the conclusion of all hot work.

Once the mitigation of the subsurface fire is complete, the northern and southern portions of the site will be graded to resemble the surrounding natural topography and revegetated with native plants. A separate City of Boulder OSMP project will redevelop the central portion of the site into a new trailhead facility once the DRMS mitigation is complete.

Most trails in the area will be open during both the coal mine mitigation work and the trailhead improvement efforts. An interim trail will be installed to provide access for visitors arriving by bike and from the Colorado Department of Transportation parking lot at the intersection of Highway 93 and Marshall Road. Please visit OSMPTrails.org to see current trail closures and view alternate destinations.

To learn more about the project, maps of the project and detours in the area please visit the City of Boulder Open Space and Mountain Parks Marshall Mesa Trailhead Project webpage. To learn more about the state’s coal mine fire reclamation program please visit the Division of Reclamation, Mining,