If a controversial land-exchange bill passes, Resolution Copper Mining LLC will acquire 2,400 acres of public land before it develops an environmental impact statement and invites public input on its planned copper mine 100 miles north of Tucson.

The National Environmental Policy Act, or NEPA, requires those steps for mining on public land.

U.S. Rep. Raul Grijalva, D-Tucson, who has been fighting the land exchange since it was introduced in 2005, said the delay of impact studies is “the crux of this fight.”

He questions why the process wasn’t launched years ago, especially considering Resolution began making plans for the mine in the early 2000s.

“They could have shut me up 10 years ago by doing the NEPA study,” Grijalva said.

Land exchanges come in two varieties: administrative or legislated, like Resolution’s proposed land exchange.

The more common administrative land exchanges — the transfer of land between federal and non-federal parties — require a government agency like the Forest Service to determine privatization of public land is in the public interest before approving the exchange.

But a legislated land exchange gives that discretion to the U.S. Congress. Those exchanges can be exempted from “environmental review or resource planning mandates,” said a 2010 policy brief from the Center for Natural Resources and Environmental Policy at the University of Montana. “Critics protest that legislative transfers of federal ownership … avoid the public scrutiny that is afforded by agency planning processes.”

Resolution Copper maintains those studies will be completed eventually and would still carry weight even after the land is privatized.

But the U.S. Forest Service, which would oversee the NEPA studies if the land remained public, says there’s no clear purpose in doing NEPA assessments after the exchange, as the agency would no longer have the authority to insist upon changes to mitigate environmental and cultural impacts to sacred Native American land. The agency opposes the land-exchange bill on this basis.

“A NEPA analysis after the exchange would not allow the Forest Service to recommend alternatives since the exchanged parcel would already be in private ownership,” Mary Wagner, associate chief of the Forest Service, said in March testimony before the U.S. House subcommittee considering the land-exchange bill.

Four years ago, Thomas Vilsack, secretary of the U.S. Department of Agriculture — which oversees the Forest Service — expressed the same sentiment in a letter to U.S. Sen. Ron Wyden, then-chairman of the Subcommittee on Public Lands and Forests. He explained the administration’s opposition to a 2009 version of the land-exchange bill.

“The bill should be amended to require the preparation of an environmental impact statement before the land exchange is completed,” Vilsack wrote.

Once land is privatized, state — not federal — mining regulations apply, and those regulations are less stringent, said Roger Featherstone of the Tucson-based Arizona Mining Reform Coalition, which opposes the mine.

But Andrew Taplin, Resolution Copper’s project director, said Wagner and Vilsack’s testimony is “not consistent” with Resolution’s interpretation of the Forest Service regulations. Resolution officials maintain that activities on adjacent public land would trigger a full NEPA study regardless of whether the mine itself is on private land.

Opponents say that trigger cannot be guaranteed, because the company has not yet issued a mining plan of operations.

Resolution intends to begin the NEPA process this year, once the mining plan of operations is submitted — regardless of whether the land exchange passes, Taplin said.

Thousands of rock climbing routes and boulder problems would also be off-limits to climbers if the land exchange passes, said Curt Shannon of the Access Fund, a national nonprofit devoted to conserving access to rock climbing areas.

Congress’s decision on the land exchange should be guided by whether it is in the public interest to privatize the land — and that demands a full NEPA study prior to a vote, said Shannon, the Access Fund’s Arizona policy analyst.

“We’d argue it’s not proper to make a public interest determination before you collect the data,” he says.

Contact reporter Emily Bregel at ebregel@azstarnet.com or 807-7774. On Twitter: @EmilyBregel