The 20-year-old ban on mining of uranium near the Grand Canyon was upheld in U.S. District Court in Arizona on Sept. 30.
The ban prevents new mining on more than 1 million acres of land.
Mining groups that sued the federal government have 60 days to appeal the decision.
Mining associations and other groups with a stake in the industry argued that the U.S. Department of the Interior had erred in the 2012 decision to ban new mining for 20 years on public land near the national park. They argued the ban was based on "overly cautious," speculative environmental risks. The withdrawal decision was based on studies assessing potential impacts on water, soil and other resources, AZ Central reported.
The ban prohibits the exploration and development of new claims but does not affect previously approved mining.
Judge David Campbell heard oral arguments on Sept. 9 and ruled Sept. 30 that then-Secretary of the Interior Ken Salazar did not violate the law when he chose to "err on the side of caution in protecting a national treasure," even if he did not have "definitive information."
A coalition of environmental groups and the Havasupai Tribe joined the lawsuit to defend the ban, saying the effects of uranium mining are long lasting and may not be fully known for decades.
Mining groups have 60 days to appeal.
Laura Skaer, executive director of one of the plaintiffs, the American Exploration and Mining Association, said she would need time to review Campbell's reasoning before deciding any next steps.