Fighting underground fires no easy task
Editor’s note: This is the second article of a two-part series.Results of a 2003 project north of Silt reflect the challenges of fighting underground fires like the one that has burned in South Canyon since 1910 and sparked the destructive 2002 Coal Seam blaze.The state hopes to fight the underground South Canyon fire this year, but it won’t be easy if the 2003 campaign near Silt is any indication.Efforts to seal off airways to that fire near Harvey Gap Reservoir have resulted in general cooling of the fire, said Steve Renner, project manager for the Division of Minerals and Geology’s inactive mines program.But the project also revealed that there are probably multiple coal seams and multiple mines at the site, Renner said. He said he wouldn’t be surprised if the project failed to reach all the burning areas.
Mac Burnett, of Rifle, who worked as a contractor on the project, said crews poured a million gallons of water and 40 truckloads of grout into the underground fires.Such fires are typically hard to put out, he said. At Harvey Gap, some parts of the mine cooled down quite a bit, and another part still has 900-degree gas coming out.”We ran out of money before we could finish that site,” he said. “If you put enough money on something like that you probably can solve it, but it’s really expensive to put that kind of material in a mine.”Renner said his program gets only about $2 million a year, through federal grants, and there are 23,000 abandoned mines statewide. The top priority is putting up signs, fencing and other protection to prevent people from getting killed around the mines.Fires are a high priority, too. But Renner said he could spend his entire budget for inactive mines just fighting a couple of fires. And there would be no guarantee of success.
“There’s no right answer on these fires,” Renner said.The Colorado Division of Minerals and Geology plans to seek bids from contractors this year to try to seal off openings and cut off airflow to the underground coal seam where the South Canyon fire is burning.That fire set off the 2002 Coal Seam wildfire, which destroyed 29 homes in the Glenwood Springs area.Another problem area is the IHI mine, which the state has fought off and on for 20 years east of Rifle Gap, Renner noted. It’s still burning, although the state had some success containing it in the mid-1990s in a project that cost about $875,000.One trick with the Grand Hogback fires is that they are associated with mines that generally were dug at the base of the formation. The miners dug fingers upward into the mountain to bring coal down. That created natural chimneys to fissures reaching the surface above, which allows fires to vent and draft.
“It’s very conducive to fires,” Renner said.Part of the work at places such as Harvey Gap involves simply trying to understand the mining and what kind of collapsing and venting occurred after the mining stopped, Renner said.Treatments can vary. Foam might be injected to try to cool a fire. A cement grout is used to try to seal off air supplies.”We’re all still searching for a really good method,” Burnett said, and a good method really needs to be inexpensive because there’s so many fires they get really expensive.”It can be hard to know immediately what kind of effect treatments such as the one at Harvey Gap have on fires.”They’re kind of cyclical in nature,” Renner said. “They’ll burn really hot and settle down and hot and settle down by kind of the nature of what goes on underground.”