Tribal leaders are preparing comments for this week's public hearing on the possible impacts of an underground copper mine proposed for the mountains east of Phoenix.
The Center for Biological Diversity says the Resolution Copper mine would destroy a site sacred to the area's San Carlos Apache tribe and could harm the environment.
The area is home to the endangered hedgehog cactus and the threatened western yellow-billed cuckoo.
Resolution company officials say they are working with tribes to identify important sites and ease negative effects.
The hearing at 5 p.m. Tuesday at the Queen Valley Recreation Hall is the last of five scheduled by the U.S. Forest Service on the draft environmental review.
The Center for Biological Diversity says a news conference is planned a half-hour before the hearing starts.