State mine safety teams are moving forward with plans to discover a second active underground fire later this year in the area where the most destructive wildfire in Colorado history started.
The Marshall Fire destroyed more than 1,000 homes on December 30, 2021. It was pushed by 100 mph winds through open spaces and into the communities of Superior and Louisville. Two local residents died.
A view of the Marshall Fire in Louisville on December 30, 2021. Marc Piscotty//Keynote USA/Getty Images
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Authorities, after an 18-month investigation, determined there were two ignition points: the first in a pile of burning wood on private property and the second under power lines. The latter is a point of controversy, as Xcel Energy does not agree with the researchers’ conclusions. The company is fighting litigation that blames its lines for at least partially causing the fire.
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One of those sites contains the Lewis Mines that were abandoned and buried in 1946. A surface vent was discovered in 2018 that emits heat measured at 120 degrees.
Colorado Division of Reclamation, Mining and Safety
RELATED Disaster declaration issued for Boulder County area to mitigate underground coal mine fire (2023)
Colorado Division of Reclamation, Mining and Safety crews began a review of the Lewis Mine site in January. Excavators carefully removed the earth adjacent to Davidson Ditch, alternately digging and filling 10-foot “fingers” of smoldering earth to prevent the concrete irrigation canal from collapsing.
Colorado Division of Reclamation, Mining and Safety
Crews dug 30 feet deep and encountered temperatures as high as 600 degrees. When readings rose above 90 degrees, crews mixed the heated soil with fresh soil and rock until temperatures fell below that mark.
Colorado Division of Reclamation, Mining and Safety
The project was completed in early April ahead of schedule.
Crews are now planning to turn terrain 2,000 feet above the Marshall Mines, a DRMS spokesperson confirmed. The department is currently in the permitting process with Boulder County as the project, scheduled to begin later this summer or fall, will impact access to county open space at the Marshall Trailhead Table.
It will be the second time mitigation efforts have been undertaken at Marshall Mines. A mine vent was blamed for sparking a small forest fire in 2005. Three years later, 275 tons of rock were dumped at the site, raising its surface 18 inches.
Boulder County
Recent Lewis Mines mitigation cost $316,002, according to department spokesman Chris Arend. The Marshall mitigation will be done now that the department has received additional federal money to address coal mine fires across the state.
In a 2018 DRMS study, there are 1,736 known abandoned coal mines in Colorado. A contractor hired by the state to examine them found that 38 were actively burning or were dormant and extinguished after a previous fire.
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Logan Smith
Keynote USA
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