On Marshall Mesa in Colorado, an excavator scooped out dirt and coal from a 30-foot pit with smoke and ash wafting from it.
The pile of dirt and coal was blasted with water every so often to cool it down. Later, the debris will be put back into the ground and buried. Hopefully, this will prevent an underground fire from starting again.
The Colorado Division of Reclamation, Mining, and Safety began extinguishing the underground coal-seam fire on Marshall Mesa in November.
An investigation into the smoldering coal seam as the possible cause of the 2021 Marshall fire initiated the project. Eventually, it was ruled out as a cause.
The Marshall coal fire is one of 38 underground mine fires across the state of Colorado. At first, the fire was deemed low risk due to its minimal activity. However, a report highlighted that it was burning beneath a popular recreational area.
Over the next 12 years, the mining division will be tackling underground fires after receiving almost $10 million yearly from the Infrastructure Investment and Jobs Act. It will cost an estimated $870,000 to extinguish the Marshall Mesa coal fire.
The coal fire has burned for at least 100 years on Marshall Mesa, which is now part of Boulder Open Space and Mountain Parks. Many mountain bikers and hikers visit the open space. In 2024, the park received 83,431 visits.
On December 30, 2021, the Marshall fire was ignited during an intense windstorm. Investigators determined that the blaze was sparked by smoldering embers from a week-old fire on the grounds of an international religious cult. The strong winds also caused a power line to snap and send sparks into the dry grasses on Marshall Mesa.
The fire killed two people and destroyed more than 991 structures, costing $2 billion. It was the most destructive wildfire in the history of Colorado.
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From December 20, 2021, to February 18, 2022, the Marshall Mesa Trailhead was closed as the cause of the wildfire was investigated.
The underground coal fire did not set off the deadly blaze, but the community still wanted something to be done about it.
It is unclear what exactly caused the fire to start burning underground, but experts know that it dates back to at least the 1920s.
There is a photograph of a boy standing on the mesa. The ground was covered in fractures, and smoke rose from the earth.
In the Marshall Mesa area, coal mines were in operation from 1863 until 1939. Experts don’t know if miners caused the fire and were unable to extinguish it or if the coal spontaneously combusted.
Throughout the years, the underground heat has caused patches of snow to melt, but no one has seen signs of venting or fracturing from the fire.
Workers at the site are aware of the fears that another wildfire will be triggered, so precautions have been put into place. They monitor the pit with infrared cameras and thermometers.
In addition, a tanker truck sprays hot spots with water to cool them down. The hottest spots that have been measured so far were 450 degrees, and coal needs to reach 750 degrees before it combusts.
The workers will also halt operations if winds hit 15 miles per hour or more to prevent sparks from flying into dry grass. The mining division even keeps 30,000 gallons of water on site in case a fire breaks out.
When the project is done, the excavation team will save some fossilized rocks and coal to display at the park so visitors can get a glimpse of the land’s history.