Beneath the quarry: Hot springs owners fear damage to caves and springs at mine site

The Rocky Mountain Resources quarry north of the Glenwood Caverns Adventure Park is shown in this October 2018 file photo.
Chelsea Self / Post Independent file

The owners of Glenwood Springs’ two major hot springs attractions say the expanded quarry could ruin the centuries-old attractions -— and not just because it could affect the views from town.

In comments to the Bureau of Land Management, Iron Mountain Hot Springs and the Glenwood Hot Springs Lodge & Pool wrote that RMR Industrial’s proposed limestone quarry expansion “will obliterate source waters feeding these springs.”

The hot springs owners, as well as cave experts, worry that five wells RMR plans to drill for a baseline study could irreparably damage the fragile and complex geothermal structures that feed the hot springs.

Groundwater flows down through caves and is heated by magma, then pushed up as hot springs. It’s unclear exactly where those pathways are, but even drilling in the area could damage the source of the hot springs.

“The Flattops area, and the area above where this quarry is going, is a recharge area to the hot springs source water,” Glenwood Hot Springs Resort and Lodge President and CEO Kjell Mitchell said in an interview.

“By drilling, there’s potential that they could disrupt the pathway, and there would probably be no way to shut it off,” Mitchell said.

The BLM is considering allowing RMR to drill the five test wells under a categorical exclusion, the least rigorous form of environmental review. The drilling is part of a hydrological study to provide a baseline for the BLM to evaluate the environmental impacts of expanding the quarry.

 Due to the public interest in the quarry project, the BLM asked for scoping comments on the categorical exclusion. About 250 community members and organizations responded, BLM spokesman David Boyd said.

All of the comments opposed granting RMR the categorical exclusion to drill the five wells. RMR also wanted permission to use a drilling method that allows them to keep core samples as research for the limestone deposits they hope to mine.

Related: RMR wants to use water study to drill exploratory holes

Steve Beckley, co-owner of Iron Mountain, and Mitchell of the Hot Springs Pool, have been reserved in their public statements about the quarry.

In a comment to the BLM about the wells, however, they did not hold back.

The test wells, though a baseline study necessary for the BLM to begin the full environmental impact statement, would itself be harmful, the two hot springs business owners wrote in their joint comments.

“(This) testing to obtain the basic background information about the larger mining operation poses dangers which should be approached only with the utmost caution,” they wrote.

Caves unknown 

There are likely caves in the mountain where RMR intends to mine, even though there are no known entrances, according to cave experts.

Cave and geology experts who also commented to the BLM expressed doubt about a cave study RMR commissioned.

Richard Rhinehart, who leads the Colorado Cave Survey’s Mid-Continent Quarry committee, said the study Collier Consulting conducted has some major flaws.

“I shared (the Collier report) with knowledgeable consultants and the consensus is that, while Collier Consulting is technically competent in their geophysical surveying, their analysis strongly suggests they are unaware of the hypogenic cave development of the Glenwood Springs area,” Rhinehart said.

“Drilling here could intersect natural cave passage which has not otherwise been altered by man. This could be damaging to natural cave life which is yet unknown,” Rhinehart said.

Collier, a Texas-based consulting company, might be more familiar with “epigenic” cave development — where water flowing from the surface dissolves limestone and creates caves, Rhinehart suggested.

Caves around Glenwood Springs show “hypogenic development,” meaning rising mineral water from underground springs, often hot and containing sulfuric acid, dissolves rock inside the mountain.

Rhinehart suggests that Collier downplayed the possibility of caves because they observed no entrances or sinkholes, which one might expect if groundwater had carved the cave.

Collier Consulting did not respond to a request for comment.

Collier’s study of the hillside, included in its application to drill the five wells, found eight anomalies in their report, a few near some of the proposed drill sites.      

“These features are interpreted as being related to possible kasrt solution features consisting of clay filled fracture zones or voids, smaller air-filled voids, competent limestone, or changes in lithologic conditions,” the consulting group concluded.

In other words, the Collier group interpreted those less solid areas underground as cracks filled with less dense clay, or piles of fractured rock, not open caverns.

The famous Glenwood Caverns, Rhinehart points out, likely had a small entrance when Charles Darrow found it in 1895. Darrow noticed the small opening from a whistling sound, which only occurs when the entrance is small, maybe an inch wide, Rhinehart said. Darrow had to hire laborers to dig an opening large enough to enter the cave. 

“A significant proportion of the anomalies are likely to represent air-filled voids, many of enterable size, at varying depths through the limestone,” John McLean, a former geophysical surveyor from Franktown, said in comments to the BLM.

“Drilling here could intersect natural cave passage which has not otherwise been altered by man. This could be damaging to natural cave life which is yet unknown,” Rhinehart said in his own comments.

The BLM will require more cave and karst surveys as part of the environmental review.

Caves under the quarry might be connected to hot springs

Beckley and Mitchell, in their own comments to the BLM, admitted that many water and cave features are simply unknown, and no one can predict with certainty what lies underneath the proposed drilling and mining site.

What is certain, Beckley and Mitchell wrote, is that caves “act as a network of pipelines and connections delivering ground water to downgradient geothermal resources.”

“Disturbing these vital connections can have catastrophic consequences,” the hot springs owners said.

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