A group representing about 350 commercial builders statewide announced Thursday it has endorsed the proposed Rosemont Mine.

The Arizona Builders Alliance’s board of directors decided unanimously to support the mine last month after taking a mine tour led by Rosemont Copper, said David Pittman, the alliance’s Southern Arizona director.

It wasn’t an easy decision because some members had negative feelings about the mine, he said, but the tour resolved the concerns.

“We went out and took the tour, everyone came away really flabbergasted with what you would call their embracing of new technologies and sustainable mining practices,” Pittman said Thursday. “I think if it’s approved and allowed it will be the most environmentally sensitive mine in Arizona.”

The mine would take 220 million pounds of copper from the Santa Rita Mountains about 30 miles southeast of Tucson. It would employ hundreds of people but has drawn opposition in part because it would also require use of more than 3,000 acres of Forest Service land for disposal of waste rock and mine tailings.

The mine has been endorsed by nine other business groups, including the Tucson Metropolitan Chamber of Commerce, the Northern Pima County Chamber of Commerce, the Tucson Utility Contractors Association and the Alliance of Construction Trades.

Opponents include numerous local governments and state legislators as well as many environmentalists and a number of tourist-oriented businesses.

Mine opponents said they were disappointed that the Arizona Builders Alliance’s made its decision without speaking to opposition groups. Morris Farr, Save the Scenic Santa Ritas’ vice president, said the group is always disappointed when interest groups decide to support the mine and only want one side of the story.

Pittman said members  felt they got a really good presentation about the mine from the copper company. In fact, “I think it’s been a lot easier to get the message from the opponents than from the company” from media reporting, he said.

“Arizona clearly needs the 2,100 jobs the mine would bring annually and the more than $700 million per year in economic stimulus that would flow into Pima, Cochise and Santa Cruz counties during the 20-year life of the mine,” Pittman said. “The Rosemont operation would result in the building of more than $900 million in roads and facilities, which would provide needed stimulus to the Southern Arizona commercial construction industry.”

The ABA is a nonprofit trade association whose members include about 150 general contractors, subcontractors, suppliers and professional service organizations in the commercial construction industry in Southern Arizona.