A final decision by the Coronado National Forest on the controversial Rosemont Mine will likely be delayed until March, the forest supervisor said Monday.

Supervisor Jim Upchurch said the release of a final environmental impact statement for the proposed mine — in the Santa Rita Mountains southeast of Tucson — has been pushed back from Sept. 27 to sometime in November because of “ongoing resolution of issues.”

Meanwhile, new regulations call for an “objection process” that could take up to 120 days — delaying a final decision for some four months beyond November.

“Once we make it (the environmental impact statement) available to the public, we’ll put a formal legal notice in the paper stating that the objection process has begun,” Upchurch said. “There’s a 45-day objection period for people who want to object to the draft record of decision. At the conclusion of that, there’s a 45-day review period, which can be extended an additional 30 days.”

Upchurch said controversy over the mine proposal by Rosemont Copper — including concerns about its impact on air quality, water resources and wildlife — is likely to require all or most of the 120-day period for resolution.

“I would assume that, because of the complexity and controversy, the soonest we’re looking at is sometime in March for a decision that would be signed and go forward,” he said.

Upchurch said the extended time period “gives more flexibility in working with the public that is objecting” to the mine plans.

“If you want to do it right, you have to go through these steps,” he said.

Mine opponents lauded the decision to delay the release of the environmental impact statement.

“The Forest Service made the right call on not rushing the Rosemont final environmental impact statement out before its serious deficiencies were addressed,” said Gayle Hartmann, president of a group called Save the Scenic Santa Ritas.

“It’s time for an analysis that fully identifies the severe, unavoidable and permanent adverse impacts that the Rosemont Mine would have on Southern Arizona’s air quality, water supplies and economy,” Hartmann said.

Jan Howard, spokeswoman for Rosemont Copper, said the company’s stance is reflected in a statement released by Gil Clausen, president of Rosemont’s parent company, Augusta Resource Corp.

“We are pleased to see the U.S. Forest Service move the final environmental impact statement and record of decision documents towards completion and provide a certain process with dates for finalization,” Clausen said. “The new regulations provide a more defensible process and remove the administrative appeal process, while following a similar time frame.

“This allows us to commence construction at Rosemont according to our planned project schedule when project debt financing is in place and detailed construction engineering is at least 75 percent complete.”

Documents provided by Augusta, a Canadian corporation, say the Rosemont site “hosts a large copper/molybdenum reserve that would account for about 10 percent of U.S. copper output once in production.”