When a mining operation spreads out across hundreds of acres, some environmental impact is inevitable. Opponents of the Rocky Mountain Industrials limestone mine expansion near Glenwood Springs say its proposed footprint of more than 400 acres would push that impact beyond what they consider acceptable.
Federal studies to determine the extent of that impact could take months, but Aspen Public Radio spoke with experts to get a sense of what they might find as part of our series "Digging Deep: What Does RMI Mean For Glenwood Springs?"
An in-depth gauge of any potential harm would come in the form of an Environmental Impact Statement – a lengthy study conducted by the Bureau of Land Management used to determine whether the mining company should get a green light to expand digging.
The agency said such a study would take "at least a year," but experts who have seen other similar mines – and conducted preliminary studies on this one – can postulate as to what an expanded mine could mean for the natural world.
Ron Cohen spent more than three decades working for both mining companies and their opponents, studying the environmental impacts of projects all around the world. He also taught about those same issues as a professor at the Colorado School of Mines.
"You can give a song and dance about how environmentally responsible it would be and all the right things that you do,” he said. "But if you're going to have a mining operation where you're moving earth, there are going to be changes and probably long-term changes."
Cohen said an Environmental Impact Statement will look for effects above and below the surface, as well as ways to mitigate them.
"It's basically a cradle to grave evaluation of what's there," he said. "What would we disturb, what are the potential implications, and how will we try to rectify those problems?"
When asked for comment on the project’s potential impacts to the environment, Rocky Mountain Industrials CEO Brian Fallin provided a short emailed statement to Aspen Public Radio.
"We are following all state and federal regulations and guidelines for mine operations," he said in the statement. "The BLM and State of Colorado allow mining in the area and we will follow the appropriate guidelines, including environmental."
The BLM’s review produces a lengthy document compiling findings by specialists – zooming in on the area’s soil, rock, and water. Some of that requires time-intensive monitoring, like drilling wells to observe underground water quality.
Perhaps the most significant environmental effects of expanded quarrying could come in the form of impacts to the area’s water. The mine sits above underground pathways that feed the city’s namesake hot springs with water, and just a stone’s throw away from the Colorado River.
Geothermally heated water used by the two commercial hot springs operators in town travels through a subterranean network of caves, tunnels and fissures – referred to as karst. Eroded limestone gives way to cavities, which carries precipitation runoff trickling down from the Flat Tops Wilderness Area to a geothermal aquifer below the surface.
Digging in the area risks disturbing that complex network of underground pathways, said Chris Sanchez, a hydrogeologist who has studied the mine site.
"We've completed tests out there where we have proven that stress at one point in the geothermal aquifer has significant impacts in another portion," he said. "The point I want to emphasize is just that there's a lot of interconnectedness and a state of equilibrium that's very fragile."
Sanchez has worked as a consultant for both Iron Mountain Hot Springs and Glenwood Hot Springs Resort since the 1990s, but has also worked for mining companies applying for permits.
He said mining in areas with firmer underground rock – such as granite – is less risky, but the system of eroded cavities created in the limestone below the proposed RMI mining site is vulnerable.
"The science is much more challenging in this type of situation," Sanchez said. "And the stakes are so much higher because if impacts were to occur to that hydrothermal aquifer, they cannot be fixed."
The BLM’s environmental review process is designed to catch any potential harm to that system before it happens, and make sure the mining company is minimizing that potential. Sanchez said the process "would probably show that the benefits of the mine outweigh the risks," but worries that the planned review would not be able to adequately gauge the risk of damage to the underground water system.
The BLM plans to drill a handful of wells as part of its pre-permit environmental study. While they are designed to provide a glimpse at the structure of the cavities and flowing water that lie beneath the surface, Sanchez said the number and location of the wells will not be enough to give a thorough assessment.
But adding more of those wells could damage the karst before the mine even gets a permit for expansion.
"There's a Catch-22 here," Sanchez said. "Because if you put in the number of wells necessary to characterize the system, then you're causing a lot of disturbance to the formation and to the groundwater flow paths. And the level of risk associated with that type of characterization would not be acceptable either."
Seriously disturbing the karst by digging could also create sinkholes. Ron Cohen said water flowing through underground caves and channels provides structural support.
"You disrupt that flow, you drain that water," he said, "And … suddenly the surface will subside and you'll form this hole in the earth."
Another source of concern is the mine’s proximity to the Colorado River. The current site is slightly more than a mile uphill from the river – whose water is a driving force behind life in the western United States.
Limestone extraction, unlike some other types of mining, does not tend to create toxic byproducts. However, experts say the fluids needed to run heavy machinery and dust kicked up by trucks could find their way into nearby water.
That is acknowledged in RMI’s proposal to the BLM, which cites "the interaction of stormwater runoff with sediment, fuel, or oil" as the "only potential source of polluting materials." The proposal tallies more than 60 vehicles that could be part of mining operations. The list includes heavy equipment such as bulldozers and excavators, as well as "30-40 offsite haul trucks" and a footnote explaining that even more trucks could be brought in temporarily as needed. RMI predicts the road leading to the quarry, the Transfer Trail, could see as many as 450 trips each day with haul trucks coming to and from the mine site.
Trucks and equipment used at the mine will require fueling and regular oil changes, potentially swapping out gallons of lubricant a few times each week, said Ron Cohen. That same equipment will likely push dust into the air, which could settle as sediment in nearby bodies of water.
RMI’s proposal includes extensive plans to mitigate dust and sediment-carrying runoff and outlines measures to prevent and contain spills.
Cohen said such plans are integral to any mine’s ability to reduce its environmental impact, but even comprehensive plans can fall short.
"You can, while doing mining, minimize the potential impacts to the environment and people," he said. "But it doesn't mean you can eliminate all of the potential problems 100%. There are some things that just due to physics and chemistry that are going to mean that there are some effects of the mining operation."
Environmentalists have flagged a slew of other potential impacts that might be found in the BLM’s study. Juli Slivka, conservation director at the Carbondale-based nonprofit Wilderness Workshop, said her concerns also include disturbances above ground.
"That's just decimating the habitat," she said. "Removing trees, vegetation, and transforming a relatively wild landscape into an industrial zone. Those impacts would be just the complete destruction of any wildlife habitat that exists there."
Slivka cited declining elk populations in the region as a reason to sustain that habitat.The extent of the proposed mining site’s importance to animals and plants will be assessed as part of the BLM’s environmental study.
Slivka’s doubts about the mine echoed a sentiment shared by many of its opposers. This mine, she said, is not appropriate for this specific site.
"We certainly don't see ourselves as opposed to development across the board," Slivka said. "We live and work in the West ourselves and appreciate jobs too. We’re concerned with development in places where it can have irreparable impacts to our public lands and to our communities and to resources that we all cherish and rely on together."
Wilderness Workshop plans to play an active role in the public comment portion of the EIS process. The BLM accepts comments on a draft of its findings, and advocacy groups often use that window as an opportunity to point out things the agency might have missed, or not studied adequately.
Slivka asserts the Trump administration proposed a number of rules to "short circuit" that period and diminish the role of public comment. She is optimistic that a BLM under the Biden administration will take environmental review more seriously.
"That gives me reason to believe that public comments will be heard and listened to," she said. "And that the BLM will do a very good job of listening to the public, taking all of our concerns into consideration, certainly taking any science or data we're able to provide into consideration."
The Environment Foundation, funded by the employees of Aspen Skiing Company, made the series "Digging Deep: What Does RMI Mean For Glenwood Springs?" possible through a grant to Aspen Public Radio.
Pueden encontrar la versión en español aquí.
