The proposed Rosemont Mine would require clearing or other kinds of disturbance of more than 5,000 acres of public and private land, and fill material would go into nearly 40 acres of washes so mine facilities could be put in place.

The U.S. Army Corps of Engineers issued the final permit needed by the Rosemont Mine on Friday, a key step toward allowing construction of the $1.9 billion project to start in the Santa Rita Mountains southeast of Tucson.

The Corps permit is the last major government approval needed for the mine, which would require clearing or other kinds of disturbance of more than 5,000 acres of public and private land. The permit, issued more than seven years after the mining company applied for it, allows Toronto-based Hudbay Minerals Inc. to place dredged and fill material into nearly 40 acres of washes so many of the mine facilities can be put in place.

It is a huge victory for the company and much of Tucson’s business community, which has campaigned actively for the project as an economic boon to one of the Southwest’s poorer large cities. Rosemont will create more than 500 jobs that Hudbay says will pay more than twice the median Tucson wage.

It’s a huge defeat for environmentalists and area Indian tribes, who have called the mine an assault on a beautiful and sacred mountain range and a threat to dry up and pollute two of the region’s prized creeks lying east of the mine site.

In approving the mine, the Corps’ San Francisco-based office overturned a negative recommendation from the agency’s Los Angeles District. The approval also came in the face of detailed objections from the U.S. Environmental Protection Agency’s regional office that handles Arizona issues.

In its permit document, the Corps said Friday that the mining company has made some adjustments in its project since the L.A. Corps office recommended denial in July 2016. The Corps also took issue with many of the EPA’s objections in its decision.

For one thing, the Corps noted that Hudbay has agreed to remove four livestock watering tanks that capture stormwater runoff from the mine site in an effort to ensure that stormwater continues flowing into downstream creeks.

Overall, “considering the need for the proposed action and the lack of other locations or methods to accomplish the proposed work, the Corps concludes that issuance of the permit is not contrary to the public interest,” the permit decision said.

The conflict isn’t over yet, however.

Before construction can start, the U.S. Forest Service must approve a final operating plan for the mine because the project’s waste rock and tailings will be stored on Coronado National Forest land.

That should come reasonably soon, perhaps in a month, said Coronado National Forest Supervisor Kerwin Dewberry.

Then, the project must overcome litigation. The Tohono O’Odham and other tribes and an environmentalist coalition including Save the Scenic Santa Ritas and the Center for Biological Diversity have already filed suit challenging the Forest Service’s June 2017 approval of the mine. Similar suits seeking to overturn the Corps permit are certain, leaders and attorneys for the opposition said Friday.

Whether the company will try to start construction before the lawsuits are decided in federal court isn’t clear.

In a news release Friday, Hudbay gave no timetable for building the mine. The company has said construction will last at least two years.

Rick Grinnell, vice president of the pro-mining Southern Arizona Business Coalition, noted that before Hudbay can start constructing mine buildings, it must install water lines, utilities, roads and maintenance facilities.

“You’re talking a year or 18 months of preparation before they even start putting in anything to start extracting ore,” Grinnell said. “It’s not going to happen overnight.”

In its news release, Hudbay official Andre Lauzon said, “We’re excited to achieve this milestone and are thankful for the tremendous support that we have received. This has been a long and thorough process for both Rosemont and the community. We are pleased with the outcome and are looking forward to what’s next in the coming weeks and months.”

The massive outpouring of public comments on this project, estimated at around 43,000 over the years, led directly to what Lauzon called a precedent-setting, world-class environmental mitigation plan whose benefits will be felt in the community far into the future.

But an attorney for the Tohono O’odham, Pascua-Yaqui and Hopi tribes called the Corps’ permit decision “egregious.” Denver attorney Stu Gillespie singled out what he called the San Francisco office’s complete dismissal of the lower-level office’s recommendation of denial.

“They’ve given it almost no treatment in their decision. They didn’t talk about it hardly at all,” said Gillespie, who noted that the Corps has refused to release that document to the tribes.

In a letter Friday to Gillespie’s Earthjustice law firm, Corps Attorney Maryann Blouin noted that the earlier recommendation wasn’t a decision, and called the document “privileged.”

Grinnell said he feels gratified that Rosemont’s permitting has finally reached fruition.

“Here’s one thing that many people don’t understand. Our global population since 1950 has increased three times, to 7.7 billion. Our use of copper has increased nine times.

“Our technology isn’t slowing down. The need for the mining industry and the products it produces, especially copper from our region, is going to be vital to our lives,” Grinnell said.

But Randy Serraglio of the Center for Biological Diversity said the Corps’ decision to permit Rosemont is based purely on politics, and won’t stand up in court.

“There’s a long, clear record of law, science and public opposition condemning the proposed Rosemont Mine,” said Serraglio, a conservation advocate for the center. “Rosemont would do devastating damage to Arizona’s water and wildlife. We’ll fight with everything we have to protect Tucson’s water supply, Arizona’s jaguars and the beautiful wildlands that sustain us all.”

The House Natural Resources Committee, whose chairman Rep. Raúl Grijalva last week grilled the Corps about its impending decision, hasn’t finished its oversight of Rosemont, said Grijalva, a Tucson Democrat.

“The Rosemont Mine will be destructive to our water, wildlife and lands in ways that cannot be engineered away,” Grijalva said. “When a mine will critically impair federally protected habitats and threaten desert water resources, that mine shouldn’t get a rubber stamp. That’s what happened today, and that’s what this committee is going to investigate before permanent damage is done.”

But Amber Smith, president and CEO of the Tucson Metropolitan Chamber of Commerce, predicted that economic benefits will start flowing to this region as soon as the mine begins operating.

“The economic benefits in the form of jobs, high wages and new tax revenues will be significant, exactly the type of jobs and stimulus we need to be able to lower poverty,” Smith said. “I am confident that Rosemont has followed all regulatory guidelines, as proven by initiation of the permit, and I’m sure that will be upheld.”

“Rosemont would do devastating damage to Arizona’s water and wildlife. We’ll fight with everything we have to protect Tucson’s water supply, Arizona’s jaguars and the beautiful wildlands that sustain us all.” Randy Serraglio, Center for Biological Diversity

Contact reporter Tony Davis at tdavis@tucson.com or 806-7746.