RBC I “These mines that are burning in Colorado have been burning for many, many years, some of them over 100 years,” said Tara Tafi, Senior Environmental Protection Specialist for Colorado Department of Natural Resources Division of Reclamation Mining and Safety (DRMS). Tafi oversees the department’s mine fire program, which catalogs, monitors and performs mitigation/abatement on a total of 38 underground fires in the state of Colorado, including three in Rio Blanco County.
“The lion’s share of them are between Glenwood Springs and Craig,” she noted, referencing information compiled in decades of reports including a study commissioned in 2018 titled “Colorado Underground Coal Mine Fires 2018 Inventory Report.”
The report by Tetra Tech explores the science behind underground coal fires in detail, catalogs 38 underground fires in the state, assesses relative risks, and recommends potential abatement/safety mitigation measures.
BLACK DIAMOND MINE
Among the fires in Rio Blanco County, the report lists the Black Diamond Mine Fire (approximately 1 mile northwest of Meeker, Colorado) at #12 overall, with a relative risk score of 4.7, or “medium risk” due to elevated vent temperatures, high concentrations of CO (carbon monoxide) and proximity to a trail system, as well as the town.
Located on a tributary of Anderson Gulch, operations at the mine go back as far as 1904, when HT archives show a banner advertisement for ‘Black Diamond Coal,” additional records show the mine was worked at the time by George M. Lord in 1906, with ads noting “the Black Diamond Mine is open.” From 1916 onward, the Electric Coal Company operated the mine, producing just over 30 tons of sub-bituminous coal (also called black lignite) until 1930 when the mine portal was sealed due to a fire. Based on records from Colorado Geological Survey, DRMS, and HT archives examined so far, it is still unclear what originally sparked the fire that is still active today, more than 90 years later.
The main vent, where “surface expression” of the fire is most evident, was the original location of the mine portal (the structure surrounding the immediate entrance to a mine). Measurements of the vent taken in 2018 registered temperatures of 439 degrees Fahrenheit around a small area of blackened, creosote-coated rocks that offer a visual indicator of its location.
2016 RISK MITIGATION
Rocks covering the area, called “riprap,” were put in place deliberately in 2016 as part of a DRMS reclamation project. Tafi oversaw the project, which sought to mitigate wildfire danger by reducing or eliminating the fire’s surface expression. Reclamation work included excavation and backfill with rocks to create a fire break between the mine’s entrance and surface vegetation.
Tafi said “In this situation it made sense to excavate it as deep as we could, cool all the materials on the surface that were burning, mix anything that had coal in it with non-carbonaceous material, like sandstone and soil, and then pack it back in and cover that whole area with rock.”
She highlighted changes as a result of the work by describing the fire’s surface expression prior to 2016 as “a series of large fractures that were all venting and all hot.” As of 2018, Tetra’s report commissioned by the DRMS notes the fire’s main vent ”had deposited creosote over an area of 100 square feet.” It also said further abatement isn’t necessary, but suggested further investigations into some vents still close to vegetation.
SKULL CREEK
On the west side of Rio Blanco County, the Skull Creek Fire offers an example of best-case-scenario outcome for a coal mine fire, as it is considered completely extinguished. Thanks to a relatively easy access location, an abatement effort (also in 2016) proved successful after mass excavation, mixing/cooling of hot materials and regrading of the area. As of February 2018, DRMS report said “no active or dormant vents were discovered, and no coal combustion or oxidation odors were noticed.” This is no small feat for what has long been described as an impossible task, especially for larger fires.
AXIAL/RINEAU 2
Two additional fires north of Meeker are at the Rineau Number 2 mine (6.5 miles) and Axial Mine (18 miles) fires. The Rineau fire is the only mine fire in the state not fully assessed for risk by Tetra Tech’s 2018 report, which states “The Rienau Number 2 Mine Fire was not visited for this inventory at the request of the landowner.” Tetra did, however, estimate the fire to pose a “moderate risk” due to historical data indicating that fire activity had decreased since 2003, when the Meeker Fire Department extinguished a small brush fire that started at the base of the hill near the backfilled mine entry.
The Axial Coal Mine fire (also known as Streeter/Collom) which is in Moffat County inside the Colowyo Mines permit boundary, was listed at #5 of 38 for risk priority in 2018. Tetra gave the fire a risk score of 6.8 due to surface temperatures exceeding 850 degrees Fahrenheit, proximity to Highway 13, and developing fractures. As it turned out, their assessment proved reasonable, as the underground fire sparked the Streeter Fire which prompted evacuations of Colowyo Coal Mine, shut down Highway 13 and burned roughly 1,600 acres.
The highest ranked hazard risks for fires as of 2018 were both in South Canyon near Glenwood Springs, with scores of 8.3 and 8.1.
ONGOING RISKS
Tetra Tech’s 2018 underground fires report notes that coal mine “susceptibility to change necessitates diligent monitoring and engineered safeguards to protect human health and the environment.” Fires can, for example, change from “dormant” and low risk to visibly-active and moderate or even high-risk, depending on what happens underneath the surface. As the flames consume coal underground, mine support structures and coal columns can collapse, destabilizing ground above to create sinkholes and other subsidence features. This type of unseen activity can also create new fractures that allow more oxygen to reach the fire, fueling it further.
In addition to the changing nature of existing fires, new fires can pop up in abandoned mines as coal oxidizes, causing spontaneous combustion. Wildfires, lightning strikes, and unsafe burning/dumping practices have also been known to spark these kinds of fires.
Fire officials on the front range have said they are investigating coal mine fires as one potential source for the deadly Marshall Fire, which burned more than 1,000 homes, the most destructive fire in state history. If investigators do pinpoint a coal mine fire as the cause, the conclusion would echo 2002’s coal seam fire in Glenwood Springs, which burned 29 homes and more than 12,000 acres.
PREPARATION IS KEY
Experts point out that these types of events, while concerning, aren’t worth losing sleep over, particularly when safety mitigation work has been done. “It’s just one of those deals where we could go and pick all kinds of those things out and it would just break us,” said Doug Overton, who served as an emergency first responder for decades, including about 10 years as Meeker’s Fire Chief. He recalled battling a fire north of Meeker that was believed to have been started by the Black Diamond Mine, though he and other local fire officials couldn’t pinpoint an exact date.
Tara Tafi said regular monitoring of coal mine fires also goes a long way to reduce risk. “We keep an eye on them to make sure whatever reclamation methods we’ve implemented have been effective, and thus far at Black Diamond it has been,” she said.
On top of monitoring, Colorado will receive $10 million in new federal infrastructure funding to combat the old fires, which could help extinguish more historic fires for good. More on that in the Colorado Sun: Colorado gets $10 million federal money to fight coal fires like Marshall Mesa (coloradosun.com)
By LUCAS TURNER | [email protected]om
