Judge Rules Forest Service Environmental Review Falls Short on Arizona Mine
A judge ruled the Forest Service's environmental analysis for Pinto Valley Mine expansion insufficient.
Why it matters: This ruling signals heightened judicial scrutiny on federal environmental reviews, affecting mining operations' compliance with the Endangered Species Act and balancing resource extraction with habitat protection.
- U.S. District Judge Dominic Lanza found the Forest Service violated the Endangered Species Act on Sept 24, 2026.
- The Pinto Valley Mine uses over 5 trillion gallons of water annually, impacting endangered yellow-billed cuckoo habitat.
- Environmental analysis excluded over 90% of Pinto Creek by limiting study to areas with groundwater drawdown of at least 5 feet.
- Judge Lanza called the Forest Service's decision arbitrary, noting it ignored broader groundwater impacts beyond the 5-foot contour.
On September 24, 2026, U.S. District Judge Dominic Lanza ruled that the U.S. Forest Service violated the Endangered Species Act (ESA) by approving the expansion of the Pinto Valley copper mine in Arizona without thoroughly analyzing impacts on critical endangered species habitat. The mine, located east of Miami, Arizona, annually uses over 5 trillion gallons of water, substantially affecting the subflow of Pinto Creek, which provides habitat for the endangered yellow-billed cuckoo, among other species.
The Forest Service's environmental review, conducted by SRK Consulting, focused its analysis only on portions of Pinto Creek where underground water tables were expected to drop by at least five feet. This excluded more than 90% of Pinto Creek from review. Judge Lanza found this approach "arbitrary and capricious," stating the 5-foot groundwater drawdown contour did not encompass the full "action area" as mandated by the ESA.
In his ruling, Judge Lanza emphasized: "The 5-foot groundwater drawdown contour cannot possibly encompass the full ESA 'action area' given SRK's express acknowledgement that the baseflow effects of the action would extend, at a minimum, to the Magma Weir, which falls outside the 5-foot drawdown contour." This means the Forest Service failed to consider all areas potentially affected by the mine expansion.
The decision follows conservation groups' June 2024 60-day notice of intent to sue the U.S. Forest Service and U.S. Fish and Wildlife Service. They argued that approvals for the Pinto Valley Mine expansion inadequately addressed impacts on endangered species. This ruling highlights the growing judicial demand for comprehensive environmental reviews and may set a precedent affecting how federal agencies assess mining projects in endangered habitats.
By the numbers:
- 5 trillion gallons annually — Water used by Pinto Valley Mine impacting Pinto Creek habitat
- 90% — Portion of Pinto Creek excluded from environmental analysis
- 5 feet — Groundwater drawdown contour used to limit environmental review