The Coconino County Board of Supervisors this week doubled down on its opposition to a uranium mine near the Grand Canyon's South Rim.

District 1 Supervisor Patrice Horstman said the Pinyon Plain Mine is a serious environmental risk, a threat to tribal lands and could permanently harm Grand Canyon water.

“Just to be clear, this is the Grand Canyon, one of the natural wonders of the world,” Horstmann said at Tuesday's meeting. “This is an area with deep historical, cultural, geographical, recreational and spiritual significance.”

Regulators are also concerned about uranium ore being shipped through Flagstaff on its way to plants in southern Utah.

The board has expressed disapproval of the mine multiple times in the past. Tuesday's vote only reaffirms that.

In its resolution, the board states it wants to permanently close the mine. At a minimum, state and federal environmental agencies must monitor water and air quality and share that data with the public on a monthly basis. The regulator is also calling for a reassessment of the environmental impact report from the 1980s.

President Joe Biden has designated approximately 1 million acres of Baji Nwabujo Itaha Kukuveni. – Grand Canyon National Monument’s Ancestral Footprints last summer – in part to prevent new uranium mining claims in the area.

Although the Pinyon Plain Mine is located within the monument, it is allowed to continue operating based on existing rights claims. Production began at the end of last year.

The mine's owner, Energy Fuels Resources, insists the mine is safe and is working with state officials to ensure compliance with all regulations.