Interior Secretary Ryan Zinke announced Monday that he is banning mining on 30,000 acres of federal lands near Yellowstone National Park.

Zinke’s order prevents all new mineral extraction in the area, known as Paradise Valley, for 20 years, the maximum period of time he could act under the law. That includes new claims for gold, silver, and other minerals.

The order exempts pre-existing mining claims. The area in question is in the southwestern part of Zinke’s home state of Montana.

"Access to public lands and water has allowed the Paradise Valley to build a world-class hunting, fishing, tourism and recreation economy,” Zinke said during a press conference in Montana. "I fully support multiple use of public lands, but multiple use is about balance and knowing that not all areas are right for all uses. There are places where it is appropriate to mine and places where it is not. Paradise Valley is one of the areas it's not."

The mining order extends a two-year ban imposed by former Interior Secretary Sally Jewell in 2016 that would have expired next month.

Zinke worked when he was a member of the House representing Montana to prevent mining in the area near Yellowstone, viewing it as crucial to his home state's tourism and recreation economy. He also said it would preserve habitat for species such as elk and mule deer.

His effort has bipartisan support.

The House Natural Resources Committee last month approved legislation sponsored by Republican Rep. Greg Gianforte of Montana to permanently ban mining there.

Conservation groups also supported the move, but accused Zinke of acting out of favor to his home state, and criticized other parts of his agenda that have included expanding fossil fuel development on public land, and opening formerly protected areas such as national monuments to mining and drilling.

“Secretary Zinke always seems to support conservation in his home state of Montana, while backing the most aggressive forms of industrial development in the other 49 states,” said Aaron Weiss of the Center for Western Priorities. “While Zinke rushes to open up places like Bears Ears, Grand Staircase-Escalante, and the Boundary Waters to copper, uranium, and coal mining, only Montana’s natural treasures get the protection they deserve. It’s now clear Ryan Zinke will only do the right thing when his political future is on the line.”