BOZEMAN, MONT. (AP) A Montana judge has blocked an exploratory gold mining project on private land in the mountains north of Yellowstone National Park.

The Bozeman Daily Chronicle reports that the ruling by Park County District Judge Brenda Gilbert invalidated the Montana Department of Environmental Quality's approval of Lucky Minerals Inc.'s plans to drill for gold in a narrow canyon.

The ruling concerned a Montana Environmental Policy Act provision preventing district judges from blocking projects based on faulty environmental analyses.

Gilbert sided with the Park County Environmental Council and Greater Yellowstone Coalition, which argued the provision violated the state constitution.

The environmental groups cheered the ruling, while Lucky Minerals CEO John Mears said the company likely will appeal.

There's already a 20-year ban on new mining claims on public land north of Yellowstone.

For more information, visit bozemandailychronicle.com.