A federal judge ruled Thursday that the U.S. Forest Service broke the law when it approved a massive copper mine expansion in Arizona’s Tonto National Forest without properly studying threats to endangered birds along Pinto Creek.
U.S. District Judge Dominic Lanza found the agency’s environmental review “arbitrary and capricious” for ignoring more than 90% of habitat used by the yellow-billed cuckoo and other endangered species. The Pinto Valley Mine uses over 5 trillion gallons of water annually, draining underground flows that feed the creek where the birds nest and feed.
Forest Service Analyzed Just 10% of Threatened Habitat
The agency hired third-party consultant SRK to assess damage from the mine expansion. But SRK only studied creek areas where groundwater would drop at least five feet — a narrow slice of the birds’ actual range. Judge Lanza said that approach violated the Endangered Species Act, which requires federal agencies to examine all land “likely to be adversely affected” by projects they approve.
The Sierra Club, which brought the lawsuit, argued the Forest Service cherry-picked data to minimize apparent environmental harm. The mine sits east of Miami, Arizona, and has operated for decades, but this expansion would significantly increase its footprint in the national forest.
Split Ruling Leaves Mine’s Future Uncertain
Lanza’s 113-page opinion delivered a mixed verdict. While he sided with the Sierra Club on the Endangered Species Act violation, he rejected other claims in the environmental challenge. He gave the conservation group two weeks to propose remedies, which could range from requiring a new environmental study to halting the expansion entirely.
The ruling comes as western water rights face mounting pressure from mining operations, agriculture, and growing cities. Yellow-billed cuckoos, listed as threatened in 2014, depend on dense riverside vegetation fed by steady water flows — exactly what large-scale mining disrupts.
The Forest Service has not yet indicated whether it will appeal or conduct a new analysis. The Pinto Valley Mine, owned by Capstone Copper, remains operational during the legal proceedings. Judge Lanza scheduled a status conference after both sides submit briefs on next steps.
Key Points
- Judge ruled Forest Service violated Endangered Species Act by limiting habitat review to areas with five-foot water table drops
- Pinto Valley Mine uses 5 trillion gallons annually, draining Pinto Creek where endangered yellow-billed cuckoos live
- Sierra Club has two weeks to propose remedies; mine remains operational pending further court action
https://www.courthousenews.com/judge-finds-feds-environmental-analysis-of-arizona-mine-insufficient/ – September 25, 2026
