State works to control burning coal seam in South Canyon
A long-burning underground coal seam just west of Glenwood Springs that’s believed to have been responsible for sparking one of the area’s most devastating fires in terms of property loss 15 years ago this month is due for a new round of efforts to keep it from spreading.
State mine reclamation officials are formulating a plan to use some 30,000 cubic yards of fill material this fall and next spring to try to block surface vents on the east side of the canyon that feed the fire with oxygen.
“It’s not something that will extinguish the fire, it’s just a way to control the fire’s progression,” explained Tara Tafi, senior environmental protection specialist and South Canyon project manager for the Colorado Inactive Mine Reclamation Program. “The purpose is to seal up the fractures on the hillside that are helping to fuel the fire.”
Two years ago, state workers drilled into the coal seam on both sides of the canyon to see how much the fire had migrated since their last efforts.
“The thing that’s complicated about South Canyon is that there are four separate seams involved, and three were mined on multiple levels,” Tafi said. “We did determine that, yes, the fire has migrated from 10 years ago, but not that far.”
The mitigation area encompasses about two acres of Glenwood Springs city land about a mile north of the landfill. A mix of soil and rock will be spread about three or four feet deep, compacted and revegetated.
The west side of the canyon where the underground fire extends is steeper and not as conducive to using the soil seal method, Tafi said. There, the state is looking to remove vegetation, as has been done in the past, to lessen the danger of wildfire.
It was on June 8, 2002, that a brush fire believed to have been ignited by a spark near one of the coal seam vents was blown into a raging inferno by hot, dry winds. What became officially known as the Coal Seam Fire ultimately jumped the Colorado River and Interstate 70 and swept through West Glenwood, burning 29 homes in its path and forcing mass evacuations in and around Glenwood Springs.
Unlike the Storm King Fire that blew up on the other side of I-70 eight years earlier, killing 14 federal wildland firefighters, no one was killed or seriously injured in the Coal Seam Fire.
The underground fire control efforts in South Canyon are part of a larger statewide effort to address the hazards that are posed by more than two dozen fires that burn beneath the steep Grand Hogback feature that stretches along a large swath of northwest Colorado, and elsewhere in the region.
In many cases, the old coal mine fires have been burning since the early part of the 20th century. About 33 such fires are burning throughout the state, said Jeff Graves, director of the state’s Inactive Mine Reclamation Program.
Since the fires were first inventoried in 1980 after Congress approved funding to states to address the fires, Graves said it’s been a priority for the state to evaluate them on occasion and try to come up with ways to control the fires or even extinguish them.
Those efforts have been site specific, ranging from pumping grout or firefighting foam into the burning coal seams to try to extinguish the fires to clearing vegetation away from the vents, soil sealing and other surface mitigation. The fires burning beneath the Hogback tend to be more challenging because of the steep terrain, which also creates a chimney effect that allows the fires to continue to be stoked, Graves said.
“There certainly is a risk with these fires in terms of the danger to start wildfires, which is why we are renewing the emphasis,” he said.
The state applies for federal funding about every three years, and currently is requesting another $500,000 for site-specific projects. Overall, the state is scheduled to spend roughly $5 million over the next five years to address underground fires at inactive mine sites, Graves said.
Drilling is also being done at another old mine fire up the Four Mile Canyon near Sunlight Mountain Resort, at what was known as the Sunshine Mine, Tafi said. There, state geologists are developing a 3D model to try to better understand why the fire burns hotter in some places and cooler in others, she explained.
“It helps us understand the fire a little bit better, and allows us look at in three dimension so that we can formulate new mitigation strategies,” Tafi said. “It’s an ever-changing process, and there is no one-stop shop for addressing them.”