The Montana Department of Environmental Quality will begin mitigation of an underground coal fire in Prairie County next month. The O’Neill Outcrop Coal Fire Reclamation Project is located about 10 miles northeast of Terry and is scheduled to start July 5.

There are two fire areas, one-quarter of a mile apart, that total 2 acres. The burning coal causes instability and failure of the overlying slopes. Cracking along the top of the bluff allows steam and combustion gases to escape.

“We’re concerned that these fires are burning within 800 feet of a ranch house and have the potential to spark a wildfire that could damage the ranch operation,” said Mike Glenn, Reclamation Specialist with the DEQ Abandoned Mine Program. “In addition, the failing slopes present physical hazards to people, wildlife and livestock if they walk across the disturbance.”

To mitigate the fires, crews will excavate the burning coal seam, spread the hot material into a quench pit, and mix it with soil and water to cool. The area will then be reclaimed by backfilling the coal seam and revegetating the disturbed area.

This year’s flood conditions and high water did practically nothing to douse the underground flames because the fire sits above the rising groundwater. “The good news is once we’ve put out the fire the revegetation should take hold and grow well because of the moist soil,” said Glenn.

A Federal Office of Surface Mining Coal Outcrop Fire grant will pay for most of the estimated $50,000 project that should take under 30 days to complete.

Over the last two years, the program has extinguished more than 10 coal fires in eastern Montana to protect public health and safety, and the environment. Coal seam fires are started primarily by lightning strikes. While coal fires can trigger wild land fires, grass fires can also ignite coal seams.