Leroy Brenteson was driving a tractor across his fields in eastern Montana nearly 30 years ago when suddenly the ground gave out beneath him. 

“There ain’t much to tell. I was driving across the fields, and I fell in,” Brenteson said. 

Brenteson, 83, lives on property that his family has owned for generations. He is one of two remaining residents in the former town of Coalridge, so named for a vein of coal that settlers began mining in the early 1900s. He knew there was a mine under his property because he had worked in that very mine for 15 years as part of his family’s business, Acme Coal Mining. He just didn’t expect to fall into it. 

“I didn’t drive into a hole; it was under-mined,” Brenteson said.  

In the years after the incident, Brenteson has worked with Montana’s Department of Environmental Quality Abandoned Mine Lands program to fill in holes across his property, remnants from a previous era. 

Since it began in the early 1980s, the Abandoned Mine Lands program has closed more than 1,600 hazardous mine openings around the state. But with almost 7,000 abandoned mines in Montana, demand for the program’s services isn’t likely to abate soon. Following a funding reauthorization stemming from the Infrastructure Investments and Jobs Act of 2021, the program has secured funds for the next 15 years of work. The Montana Department of Environmental Quality manages the AML program, which seeks to protect public health, safety and property from the adverse effects of mining.

The $2.8 million that AML receives each year from the federal government comes primarily from a fee on coal mining. As such, the focus of the program is on closing abandoned coal mines, but AML works with mineral and metal mines, as well. 

The type and concentration of abandoned mines varies across the state. The town of Coalridge is located in Sheridan County, which, according to the Montana Bureau of Mines and Geology’s abandoned and inactive mines database, has an estimated 40 abandoned mines. Most are coal or gravel mines. Just to the south, Roosevelt County has 101 abandoned mines. 

View of the mine and village at Coalridge, Montana, circa 1910. Photo by Martin Rostad, courtesy of the Montana Historical Society Research Center

“These are little old farmers back in the homesteader days that got a little hole in the hill and took out — it’s usually poor-quality — coal to heat their houses or their barns,” longtime eastern Montana resident Connie Iversen said. 

Iversen and her husband, Dick, own and operate a cattle ranch along the Missouri River that sits on the border of Roosevelt and Richland counties, about 24 miles west of the North Dakota border. The Iversens weren’t aware there were old mines on their property until two of them caught fire. 

In 2017, a prairie fire ignited by an spark from a neighbor’s metal cutter burned roughly 8,000 acres across the Iversens’ land and neighboring properties. It wasn’t until a windy fall day two years later that the Iversens noticed smoke and realized two abandoned coal mines were burning on their property. 

“You could stand on [the ground] and feel the heat 20 feet away,” Dick Iversen said. 

Their first call was to the local fire department. As one of the firefighters was walking along the fire and trying to extinguish it, he fell up to his waist into a burning coal seam. Dick Iverson said other firefighters were able to pull him out, but the firefighters legs were badly burned and required hospital treatment.

The Iversens’ next call was to the Department of Natural Resources and Conservation, which directed them to the AML program and Scott Graham, one of just two field employees working in the program. 

Graham uses software like Google Earth to identify possible abandoned mines before heading out to the site. Occasionally, he will get a call from landowners like the Iversens who are having trouble with a particular mine. 


Tracking eastern Montana’s silent firestarters

Underground coal seams are part of the landscape in eastern Montana, and can burn unnoticed for years. As summers get hotter and drier, the quiet burns can get out of hand, as happened with the Richard Spring Fire last summer. Mapping the smoldering seams is one way to address the risk early, and Custer County…

In the case of abandoned coal mines, Graham said once a coal seam catches fire it essentially burns until the coal runs out. Graham visited the Iversens’ property in June 2020 to survey the extent of the undermined area and determine if it was eligible for AML funding. Graham then hired a contractor to facilitate the rehabilitation of the coal mine, which he estimates dates back to the early 1900s.

The burning coal seam was dug up in three places. In each area, workers mixed the burning coal with soil and water to quench the fire before putting the material back in the ground. Then they graded the surface to match the natural contours of the land and seeded the ground with native grasses. 

Such work can be costly, but Graham said the agency is good at leveraging funds and working with other groups like the DNRC to help communities and property owners not only reclaim sites but make them beneficial.

“We show up with a wheelbarrow full of money,” Graham said. 

Qualifying for AML funding was crucial for the Iversens. The cost of excavating and extinguishing the fires without county and state assistance would have been significant. 

“You can’t afford not to because it could burn the whole countryside down in the middle of the night,” Connie Iversen said. 

Despite the fires on the Iversen property, which weren’t extinguished until the spring of 2022 due to the dangers of digging them up during an ongoing drought, Connie Iversen said they’re not too concerned about discovering another mine on their land. 

“Worried? No, not really,” she said. “I wouldn’t be surprised if we had another one, but it’s not something that keeps us awake at night.” 

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Ella Hall is a relative newcomer to Montana, having moved to Missoula in the fall of 2022 to start graduate school at the University of Montana’s environmental science and natural resources journalism program. During her first year of grad school, she has freelanced for the Missoula Current and Modern Farmer.