Some panelists who voted no considered the decision "premature."
"What I worry about," board member Robert Paine said, "is that everybody will put enormous energy into this, and we will end up adjudicating it forever."
But Amanda Smith, a board member and executive director of the Utah Department of Environmental Quality, urged colleagues not to let long-standing disagreements with the EPA "paralyze" the project.
Even though Kennecott's planned expansion would lead to the removal of massive amounts of rock the company wants to excavate up to 260 million tons a year, compared with the 197 million tons now allowed Smith said "extensive" analysis by the state has indicated that the project wouldn't exceed air-pollution standards.
"Our No. 1 priority and EPA's No. 1 priority is the protection of human health and the environment," Smith said. "At the same time, we are a regulating authority. Utah businesses depend on us to get permits so they can do what they do every day."
Although Wednesday's vote marked a pivotal victory for Kennecott's so-called Cornerstone project, the company still must receive more than two dozen other regulatory approvals before expansion can begin.
Much is at stake for Kennecott. By extending the perimeter of its mine farther south into the Oquirrhs and digging deeper for ore, the company says it can add nine more years to the productive life of its Bingham Canyon Mine.
"We applaud the decision by the air-quality board," Kennecott spokeswoman Jana Kettering said. "This allows us to continue our operation through 2028. It is a good step, not only for the economy but also for the environment."
Beverly Terry disagrees. The Salt Lake City resident watched the deliberations which lasted nearly three hours with a sign propped on her lap. The placard, showing drops of blood pooling into dollar signs, read, "Our children die so you can make a profit."
"This is a severe health issue," she said. "They say they are fixing the air, but they really aren't."
Kettering says the expansion won't lead to more air pollution from, say, ore-heaped trucks kicking up dust. To the contrary, she says, the company will see an overall decrease of 9 percent in emissions because of the project, thanks to better dust-suppression techniques, more fuel-efficient vehicles, the conversion of a coal-fired power plant to natural gas and more.
"We don't believe that for a minute," said Brian Moench, president of Utah Physicians for a Healthy Environment. "There is no credible information to suggest that they can actually do what they are saying."
From Moench's perspective, Kennecott is getting permission to expand an operation that already violates EPA standards. Although the state allows Kennecott to haul 197 million tons of rock a year, the latest federal limit was 150 million tons. Now regulators are approving an even higher production standard.
"Another increase," Moench said, "makes it even more illegal."
In a Feb. 25 letter, regional EPA official Deborah Lebow Aal criticized Utah's air-quality plans and questioned Kennecott's proposal.
"Our preliminary determination ... is that the proposed revision for Kennecott's [Bingham Canyon Mine] expansion will not be approvable," the letter said. "However, this determination should not be considered our final decision."
The state remains confident it can iron out its differences with the EPA. Staff relationships with federal regulators, Smith said, are already improving.
As for a bigger mine, Smith stands behind her staff's conclusion: "With Kennecott's expansion, we will maintain the required air quality."