A proposed copper mine 70 miles east of Phoenix is facing another legal setback. The Arizona Court of Appeals has sided with the San Carlos Apache Tribe in its latest bid to keep Resolution Copper from moving forward.

In a 2-1 decision the justices ruled that the Arizona Department of Environmental Quality illegally authorized a permit for Resolution Copper to release pollutants into the environment, without first setting discharge limits.

This ruling overturns a lower court’s decision and also requires ADEQ to restart the permitting process “consistent” with provisions in the court’s opinion.

The tribe has vehemently opposed construction of the mine over concerns it would destroy Oak Flat, which they say is a sacred Apache religious site in Tonto National Forest.