State reclamation officials handed off the Marshall Mesa Trailhead project to the city of Boulder on Thursday morning, marking the next step in an effort to mitigate subsurface coal fires and rebuild the popular trailhead. 

Marshall Mesa Trailhead sits on the southern end of Boulder and connects trail users to a system of hiking, cycling and equestrian trails that weave around Marshall Mesa and the Greenbelt Plateau. 

Underneath the trailhead — which sees more than 200 visitors per day on average — a coal seam fire smoldered for about 100 years. 

Since October, the trailhead has been closed to cool the subsurface fires, with officials from the Colorado Division of Reclamation Mining and Safety stepping in to handle them, blending hot coal with cold soil and rock to cool it to under 80 degrees Fahrenheit.

During their mitigation efforts, officials measured temperatures over 500 degrees underneath what used to be a parking lot, they said.

Now that they’ve been successful in cooling the fires, their team is handing the area back to Boulder Open Space and Mountain Parks — which will start the second part of the project to rebuild the trailhead.

Construction will begin this spring and last through the summer, with the trailhead planned to open in the fall. In the meantime, the trail systems are still open and accessible, with access maps available on the OSMP website and on signage near the trailhead.

Dan Burke, the director of Boulder Open Space and Mountain Parks, said the south Boulder trail system is “one of the most beloved areas” for recreation in Boulder.

“Out of this is coming a wonderful community good, not only in the reclamation project, but in the community benefit that’s to come,” Burke said.

Jeff Haley, a deputy director for OSMP, said the new trailhead will focus on accessibility, making parking and the trails themselves more easily accessible to users, adding new restrooms and including shade structures and a nature discovery area aimed at children. 

The project also serves as a “rebirth” of the area following the 2021 Marshall fire, which left more than 1,000 families homeless and two people dead, he said. The underground smoldering was determined not to be the cause of the Marshall fire, officials said.

U.S. Rep. Joe Neguse, D-Lafayette, said the project is the “perfect opportunity to turn tragedy into triumph.”

“We all remember the devastation of the Marshall fire not too long ago,” he said Thursday. “This particular threat will now be resolved … it’s an important preventative step.”

In addition to trailhead improvements, the coming construction will include the addition of a 20,000-gallon water tank for Mountain View Fire Rescue, which Deputy Chief Jeff Webb said will help them keep surrounding homes safe in the case of a fire in the area.

While the Marshall Mesa coal mine fire risk has been mitigated, there are still more than 38 smoldering subsurface fires across the state, according to Tim Mauck, the director for the Colorado Department of Natural Resources.

The fires can sometimes burn to the surface, spark wildland fires and release dangerous noxious gases, he added, calling the issue “not easily addressed.”

The risks are “episodic, but unpredictable,” said Jeff Graves, the director of the Inactive Mine Reclamation Program with the Colorado Division of Reclamation.

The Infrastructure Investments and Jobs Act, passed in 2021, provided Colorado with nearly $10 million to clean up abandoned land mines, like that at Marshall Mesa, according to Mauck. Projects exist around Colorado, in places including Fremont County, Glenwood Springs and Gunnison Valley.

In January, the White House imposed a freeze on federal grants and other funding, pending what administration officials said was a review of previously allocated program spending to determine whether it complied with President Donald Trump’s policies, as well as with federal laws.

The freeze was lifted Wednesday, and Marshall Mesa project officials said the freeze didn’t have a major impact on operations at the site. 

While they had to pause a few things and looked at some alternative funding sources, the construction season is early, so the freeze did not have a huge impact on their timeline, Mauck said.

“The Marshall Mesa Coal Fire Mitigation Project is a collaborative effort to strengthen community resilience and reduce wildfire risk,” Neguse said. “This project exemplifies the power of partnerships in safeguarding our lands, homes, and future generations.”