Colorado Threatens Its Largest Coal Mine With Sanctions As Green Groups Demand Harsher Penalties
Colorado regulators warned the West Elk coal mine in August that it could face sanctions after its air pollution climbed to nearly four times the level its permit allows.
Simon August · Sep 28, 2026 · 3 min read

Colorado regulators warned the West Elk coal mine in August that it could face sanctions after its air pollution climbed to nearly four times the level its permit allows.
The mine’s emissions of volatile organic compounds, pollutants that contribute to smog, reached 1,723 tons over the 12 months ending in May, far above the 465-ton limit in its air permit, according to a state compliance advisory the Colorado Sun first reported Monday.
Environmental groups led by the Center for Biological Diversity — which calls West Elk Colorado’s largest coal mine — urged the state Thursday to go beyond fines and order the company to install the best available technology to control its emissions, the outlet reported.
“This is the single largest industrial source of methane in Colorado,” Jeremy Nichols of the Center for Biological Diversity told the Colorado Sun. “What’s going to happen next? Are we looking at 2,000 tons, 5,000 tons?”
The Colorado Air Pollution Control Division does not have a timeline for finishing its investigation, and state law lets it pursue compliance orders, penalties and permit-related actions, spokeswoman Kate Malloy said in a statement to the DCNF.
The mine has told regulators it restricted public access near its main ventilation shaft, Malloy added. The division has also asked the company to evaluate what risk its elevated emissions pose to people and air quality.
“Our full investigation could identify additional alleged violations and result in an additional compliance advisory,” Malloy noted. “We are committed to ensuring that Colorado’s air is protected, and that the state enforces the Clean Air Act to its fullest extent.”
Core Natural Resources, which owns the mine, the Colorado Mining Association and the Center for Biological Diversity did not respond to the DCNF’s requests for comment. The office of Democratic Colorado Gov. Jared Polis did not immediately provide a comment on the record.
The mine’s rolling 12-month emissions more than tripled from 535 tons in January, according to the advisory as described by the outlet.




