Federal regulators on Friday rejected a mining company’s request to reduce the size of a habitat for endangered jaguars in the Santa Rita Mountains near Tucson.

Hudbay Minerals petitioned the removal of 50,000 acres of land, which would contain the proposed Rosemont Copper Mine. 

The company deemed the land unnecessary to protect the jaguars, but the U.S. Fish and Wildlife Service says the proposal failed to explain why those areas should no longer be considered an essential habitat.

Activists say the stretch of land is also an important pathway for jaguars between the U.S. and Mexico.

Hudbay has been attempting to build the mine for over a decade, and has met multiple challenges from environmental activists, local tribes and elected officials.

The Center for Biological Diversity says the project would threaten more than a dozen endangered and near-endangered species.