The plan defines the project scope and how the company will operate the US$1.9 billion copper-molybdenum-silver openpit project on the eastern slope of the Santa Rita mountains southeast of Tucson.

When completed, the mine is expected to produce 127,000 tonnes per annum of copper concentrate at cash cost of $1.14 per pound over its nearly 20-year mine life.

The Forest Service first approved the mine, which will be the third largest US copper pit, in June 2017 and the Army Corps of Engineers approved a federal Clean Water Act permit for the project on March 8.

"Receiving the MPO is an important milestone that completes the permitting process at Rosemont," said CEO Alan Hair.

"With the receipt of the Section 404 water permit, an agreement to consolidate 100% ownership and receipt of the approved MPO (mine plan of operations), Hudbay continues to move the project forward." 

"Rosemont is now a fully permitted, shovel-ready copper project and we look forward to developing this world-class asset."

Hudbay last week said it would buy out its minority partner at Rosemont for $75 million and announced plans to seek a development joint venture partner for the project.

However, all is not plain sailing just yet, as environmental and community groups and three Indigenous tribes have filed a lawsuit with the aim of overturning the Forest Service decision. They have threatened to also sue to overturn the Corps' decision.

The Forest Service has posted the comprehensive MPO on its rosemonteis.us website.