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Cemex’s Cement Plant on June 13, 2022, near Lyons. (Hugh Carey, The Colorado Sun)

Boulder County residents driving Colorado 66 are all too familiar with the view on the way to Lyons or Rocky Mountain National Park: A big Cemex quarry on the north, gouging into a popular open space area and tumbling rocks into a conveyor belt overhead, and the imposing smokestacks of the Cemex cement kiln on the south. 

Some residents and environmental advocates have long wanted to get rid of all of it. 

Now Cemex is offering a deal: The kiln, which spews out some of the largest amounts of greenhouse gases of any industrial plant in the state, could theoretically stay open forever. But Cemex would shut it down for good in 2037 if Boulder County renews its mining permit at the quarry across the street for the same amount of time.

And when it’s all done, the county can exercise the options it holds on much of the company’s land and create an open space mecca. Cemex is even offering to reduce the price of the options for an open space expansion of 1,800 acres.

But is it a deal with the devil of long-term pollution and disruption?

Boulder County Parks and Open Space Director Therese Glowacki has signed off on Cemex’s application to extend the mine permit 15 years as part of the deal. But she understands it’s the kind of policy dilemma that county residents need to weigh in on, loud and clear. 

Mining operations across the highway from the Cemex cement planton June 13, 2022, outside Lyons. (Hugh Carey, The Colorado Sun)

“It needs to have a community conversation, without a doubt,” Glowacki said. “That’s their job, at the planning commission and the county commissioners.”

Boulder residents and public officials “have always led on climate,” said Jeremy Nichols, who has fought battles over the Cemex plant and other large industrial polluters for WildEarth Guardians. “I hope that they’re really genuinely trying to look out for that part of Boulder County and their landscape. That overall area is a pretty special place. So I would hope that they’d want to move away from industrial uses as quickly as possible.” 

The EPA’s greenhouse gas emissions locator says the Cemex plant at Lyons put out 357,000 tons of carbon emissions in 2020. Cemex has been moving toward less carbon intense Portland limestone cement over the past 15 years, and “the lower carbon material is expected to become the plant’s primary product this summer,” said Walker Robinson, a spokesman for the Mexico-based maker and distributor of cement, ready-mix concrete and aggregate materials.

Still, Robinson pointed out, without a new agreement, the quarry and the kiln are separate operations, and the Lyons cement plant “can continue to operate if the quarry ceases operations.”

“Cemex has been part of the Lyons community for years, and the materials we’ve produced at the plant have been crucial for the construction of Colorado roads, businesses and schools,” Robinson said. “We believe the proposal to extend the quarry operations by 15 years and end cement manufacturing at the conclusion of the extension could clarify future plans for the operations, benefitting both our neighbors and our employees, as we all look to the future.”

A sign just outside the Cemex’s Cement Plant on June 13, 2022, near Lyons. (Hugh Carey, The Colorado Sun)

The mine, called Dowe Flats, is surrounded by Rabbit Mountain Open Space on the north side of Colorado 66. The cement kiln on the south side of the highway is also surrounded by open space, including Heil Valley Ranch. With an updated options agreement, Boulder County would have a future right to acquire 974 acres for open space on the Dowe Flats side. 

The proposal also includes a new option to buy 830 acres around the cement kiln for more open space, and a trail easement along St. Vrain Creek in the area Cemex would retain, for a regional trail connector linking Lyons to Longmont, Glowacki said. 

“Once the mining is complete, and they restore it, then all of that land will become open space,” Glowacki said. Three years of reclamation in the agreement would include removing the conveyor tube over the highway. 

In addition to the other parks, there are nature preserves with habitat for eagles and other wildlife, all of which would benefit from connections to more preserved land. “So that’s a huge boon,” she said. 

Boulder County planners will analyze the proposal to extend the mine permit with the open space options, said Community Planning and Permitting Director Dale Case.

The mining operation and the cement kiln operated by CEMEX in Lyons are surrounded by open space, and county options to expand the open space with purchases if a grand bargain with the company gets approval. (Boulder County Parks & Open Space handout)

“They’ve proposed it as a mitigating factor,” Case said. “I think there are a lot of pluses to that idea that we can look at, but we need to have that discussion.”

It’s unclear how much of the Boulder County discussion about Cemex can or should focus on greenhouse gas emissions. While the mine permit is a county issue, the air pollution from the kiln is permitted by the state’s Air Pollution Control Division. The county Planning and Permitting staff can look at air pollution from the mine, noise and other factors, Case said. 

“Whether that includes some of our climate goals as well, again will be a discussion point as we move forward,” he said. 

Once the staff has reviewed the application, the proposal will go to the planning commission, where the public can comment. The planners will make a recommendation to the county commissioners, where public testimony will again be included. 

Let the debate over the industrial sites begin anew, Nichols said. 

“It’s outlived its usefulness already, and I can’t imagine it going for another 15 years without major issues arising,” Nichols said. “But it’s an interesting concept. I guess I don’t want to just dismiss it out of hand.”

Michael Booth

Michael Booth is a Colorado Sun reporter covering health, health policy and the environment. Email: Twitter: @MBoothDenver