A Senate panel approved a compromise bill on Wednesday that gives the secretary of agriculture authority to approve a land exchange near Superior that could clear the way for North America's largest copper mine.
The compromise would require an environmental study before Resolution Copper Co. could proceed, an element that conservation groups said was lacking in earlier versions of the bill.
The bill approved by the Energy and Natural Resources committee would give Resolution, a subsidiary of global mining giant Rio Tinto, three years to develop a mining plan.
The Department of Agriculture would then have three more years to conduct an environmental study before deciding whether to permit the land swap. The agriculture secretary would still have the discretion to accept or reject the swap.
If approved, subsidiary Resolution Copper Co. would get about 2,400 acres in the Oak Flat area of the Tonto National Forest in return for giving the government more than 5,500 acres of environmentally sensitive land throughout Arizona.
The agreement was reached in negotiations between the staffs of Sen. Jeff Bingaman, D-N.M., the chairman of the committee, and Sen. John McCain, R-Ariz., a member of the committee.
McCain and Sen. Jon Kyl, R-Ariz., had co-sponsored a bill that would have authorized the land swap to go forward without giving the secretary veto power. Rep. Ann Kirkpatrick, D-Ariz., has introduced a similar bill in the House.
The proposed land exchange "presents a tremendous opportunity for land conservation and economic growth in Arizona," McCain said in a statement. He said the copper mine offers the state "a long-term investment for generations to come."
Opponents of the proposed mine said the compromise doesn't allay their concerns because it puts a congressional stamp of approval on a deal before environmental assessments are done. The area is near a key birding area, sites sacred to the San Carlos Apache and Fort McDowell Yavapai Indian tribes and rock climbing spots.
"We have asked them to do an analysis before the bill goes forward," said Sandy Bahr, director of the Sierra Club's Grand Canyon Chapter. "In effect, (the bill) says we're going to do the deal. You think that after three years of development and more time to study it that they're going to stop the deal?"
Environmentalists said the mine could contaminate water supplies and damage pristine scenic areas. Tribal leaders have also said they fear sites containing religious and cultural artifacts will be damaged by mining operations. Supporters of the mine said the project will create hundreds of well-paying jobs.
McCain has been trying for several years to win approval for the swap, which is expected to generate tens of billions of dollars in income for the mining company over the life of the mine. Earlier this year he placed "holds" on several of President Barack Obama's appointees to public lands posts in response to the administration's refusal to endorse the swap.
Rep. Raul M. Grijalva, D-Ariz., said in a statement Wednesday that the Senate committee shouldn't have approved the legislation without first investigating Rio Tinto's human rights record.
"This company has as bad a record as you'll find anywhere in the world," Grijalva said.
Associated Press Writer Bob Christie in Phoenix contributed to this story.