Team to begin mitigating second underground mine fire near Boulder County

BOULDER COUNTY, Colo. — State crews completed the Lewis Mine Fire mitigation project in April ahead of schedule, and the Division of Reclamation, Mining and Colorado Safety and Security (DRMS) is looking to tackle the Marshall Coal Mine fire next.

These two sites began to attract a lot of attention following the devastating Marshall Fire that killed two people in 2021 and burned 1,000 homes and businesses.

Authorities do not believe these underground mine fire sites contributed to the fire. Instead, the Boulder County sheriff said, it was likely due to a downed Xcel power line and embers from an earlier fire buried on private property.

Since the historic Marshall Fire, monitoring of the site has shown no change in temperature or surface expression.

This is why the Lewis Mine Fire Mitigation Project was implemented first. DRMS crews said there was increased mine fire activity, surface fracturing and cracking, and higher surface temperatures.

Efforts during the Lewis Mine Fire have not impacted Boulder County or the city's open spaces, but they could affect the area near the Marshall Mesa Trailhead.

Denver7 is working to confirm when the Marshall Coal Mine Fire mitigation project will begin. We know that leaders previously announced that it would begin this year.

Mitigation efforts involve crews digging about 30 feet underground, just below the coal concentration, and removing any burning or smoldering coal, according to Boulder County. The coal is then mixed with rock or soil and monitored until it is below 100 degrees Fahrenheit. DRMS monitors the site during this process to ensure the surrounding area remains safe and will not dig on high wind days.

Officials are aware of at least 38 total coal mine fires in Colorado, including the Lewis Mine Fire and the Marshall Coal Mine Fire, according to the state's 2018 coal mine inventory report. fires in Colorado's underground coal mines.

More than 250 have been reported nationwide as of September 2021.

These underground fires can burn for decades, according to Smithsonian Magazine. They start when the coal is exposed to oxygen, creating a chemical reaction that produces heat. This process can develop for years and the danger is that it could spontaneously ignite.

Team to begin mitigating second underground mine fire near Boulder County