The environmental groups that sued to halt the project praised the appeals court panel’s swift decision.

(CN) — A federal appeals court panel Friday halted an exploratory gold drilling project in the eastern Sierra Nevada that was set to begin this week.

Kore Mining Ltd. planned to drill for gold near Mammoth Lakes. The project involved 12, 600-foot deep holes on some 1,900 acres. It would have required vegetation clearing and less than a mile of temporary access roads.

Four groups — Friends of the Inyo, the Center for Biological Diversity, the Western Watersheds Project and the Sierra Club — sued Kore Mining and the U.S. Forest Service in October 2021, arguing the drilling would impact area groundwater that feeds into the Owens River and cause the bi-state sage grouse to abandon its habitat.

A federal judge in March sided with the defendants. The environmental groups appealed, leading to the three-judge pane of the Ninth Circuit to hear the matter on Aug. 24.

“In light of the fact that the court previously granted the unopposed motion to expedite to ensure a ruling before September 1, 2023, and the fact that the failure to act may deprive the prevailing party of the requested relief, this case presents a unique circumstance where an immediate ruling is warranted,” the panel’s brief order issued on Aug. 25 reads.

The order indicates a longer opinion will be issued at some point in the future.

“We are so thrilled that the appellate court acted quickly,” said Wendy Schneider, executive director of Friends of the Inyo, in a news release. “The impacts to the ecosystem, including sensitive species, and to the local community deserve an in-depth, detailed evaluation. Friends of the Inyo will keep working to protect this special area from destructive mining impacts.”

The environmental groups in their lawsuit argued the Forest Service used two categorial exclusions instead of a more detailed environmental assessment when examining the project. That path ignored the effect on the sage grouse, as well as possible harm to nearby, endangered Owens tui chub, a type of fish.

The bi-state sage grouse is a distinct population of the greater sage grouse. They’re known for showy plumage and mating dances that include popping sounds with inflated air sacs. They only live along the California-Nevada border.

Attorneys on Thursday argued over the categorical exemptions, and whether a one-year drilling window, followed by extended habitat restoration, was one project or two. The environmental groups said the Forest Service bypassed a more stringent environmental review process, splitting the projects into two and using different categorical exemptions, with different requirements, to gain approval.

Kore Mining said its project application met the required standards and the standards for a categorical exemption. It argued the project posed no significant or cumulative negative impacts and included long-term monitoring.

“Exploratory drilling for gold can cause a lot of harm to the environment in a year, especially to sensitive wildlife habitat,” said Lynn Boulton, chair of the Sierra Club’s Range of Light Group, Toiyabe Chapter, in the release. “After the Ninth Circuit’s ruling, the Forest Service will now have to prepare a comprehensive environmental assessment subject to full public review — as it should have done from the start.”

Representatives for Kore Mining and the Forest Service did not immediately respond to a request for comment.

In the 2-1 ruling, U.S. Circuit Judges Roopali Desai and Lucy Koh, both appointees of President Joe Biden, voted to reverse the lower court’s decision, while Judge Patrick Bumatay, a Donald Trump appointee, dissented.