The National Park Service is asking state regulators to require Rosemont Copper Company to make significant revisions to its draft air quality permit to lessen the possible impact of the proposed massive open pit copper mine on the Saguaro National Park.
The park service is requesting that Rosemont be required to include in its air quality permit application a plan for controlling dust from 70-story high, dry-stack tailings piles that will cover more than a 1,00o of acres of Coronado National Forest.
The current draft air quality permit under review by the Arizona Department of Environmental Quality does not require Rosemont to submit a tailings management plan prior to approving the permit.
Instead, the draft air permit allows Rosemont to submit a tailings management plan 90 days prior to startup of operations.
“Given the significance of this plan to successfully control air pollution from mine operations, it is appropriate to require this plan as a part of the permit application,” Susan Johnson, chief of the NPS policy, planning and permit review branch, wrote in an Oct. 31 letter to ADEQ.
Johnson stated that past Arizona projects similar to Rosemont “have demonstrated that the management of tailings is a significant factor in controlling particulate emissions.”
The Park Service is also objecting that Rosemont is including emissions from dynamite blasting as “fugitive” NOx emissions. Rosemont is projecting the mine will generate 154 tons of fugitive NOx emission per year.
“The NPS does not consider NOx emissions from blasting as fugitive emissions since “blasting” NOx emissions have both velocity and buoyant heat in its plume rise component, and are not passive fugitive emissions such as windblown dust,” Johnson stated.
The park service wants NOx emissions from blasting to be considered as non-fugitive emissions and subject to a revised visibility analysis of the mine’s impact on Saguaro National Park, located about 30 miles east of the mine site.
That analysis, the park service said, could result in “further consideration of mitigation” needed to protect the park.
The park service’s objections signal possible further delays in ADEQ issuing a final air quality permit for the mine. Earlier this month, the Forest Service indefinitely delayed release of the Final Environmental Impact Statement (FEIS). One of the reasons cited for this delay was the need for more studies about the mine’s potential impacts on air quality and other issues.