Guest opinion: Quarry’s hydrologic drilling proposal just too risky | PostIndependent.com

Guest opinion: Quarry’s hydrologic drilling proposal just too risky

Professor Emeritus Garry Zabel, geology, Glenwood Springs-Spring Valley.
Doug Stewart

RMR’s hydrologic drilling proposal presents many serious issues. I oppose the expansion of the limestone quarry that RMR is proposing for the following reasons.

1. The last sentence of the first paragraph of the Baseline Study states “Monitoring well locations … to … avoid known cave/karst resources, …” Do we really know enough about the cave/karst system to adequately evaluate this? Has RMR/Mid-Continent intersected any of these features in the past? What is their plan if they were to intersect such cave/ground water features? What would be the result of this intersection to the groundwater system?

Since cave systems are usually interconnected, could this drilling cause any changes in the hydraulic system that supplies geothermal waters to the local hot springs pools? Can we afford to take this risk?

We know from studies on the Glenwood Springs geothermal system that the geothermal water is within a connected confined aquifer within the Leadville Limestone. The Leadville Limestone is the formation that RMR is currently quarrying and is planning to quarry in their expansion proposal.

For the small quarries, there isn’t as much potential to disturb the geothermal system. However, exploratory wells and the massive increase in the size of the quarry would increase the chances of affecting this sensitive system. Again, too risky?

2. In the second paragraph, RMR stated that a sixth well may be drilled on private land “on the opposite side of the West Glenwood fault.” Has RMR or anyone else studied the possibility that this sixth well or any of the other five wells could disrupt or change the rate of flow of the hot springs that feed the Iron Mountain or the Glenwood Hot Spring pools?

3. Wright Water Engineers of Glenwood Springs, in the late 1980s, drilled an experimental well to determine the geothermal possibilities. The well was located northeast of the intersection of Seventh Street and Blake Avenue. Among other things, they determined that the geothermal aquifer is a very sensitive and fragile system (as mentioned above).

Their data indicated that the water level rose and fell periodically. They were then able to trace these cycles to trains running through Glenwood Springs. They were even able to determine whether or not the train was a freight train, which had the highest water level rise vs. a passenger train, which had a lower high-water level.

Since freight trains are longer and heavier than passenger trains, they put more pressure on the geothermal system than passenger trains, therefore a greater rise in the well water level. The water level returned to a lower, baseline level when there were no trains passing through Glenwood Springs. Wright Water Engineers eventually abandoned the geothermal test well.

The risks are too great.

Garry Zabel of Glenwood Springs is a Colorado Mountain College professor emeritus in geology. This commentary was also submitted as a letter to the Bureau of Land Management during their open comment period regarding the mine application.


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