Southern Arizona’s dark skies established the region as an international hub for astronomy in the 1960s. Observatories and other sky-gazing research facilities have brought prestige and millions of dollars to the state.

Today, riches on the ground or, more specifically, below it also have the potential to enrich the state, resulting in an odd collision between mining and astronomy.

Since 2007, when Rosemont Copper, which is owned by Canada’s Augusta Resource Co., announced its plans to build a mine in the desert just south of Tucson, the environmental community has warned that the project will devastate the desert landscape.

But when the mine released its draft environmental impact statement in 2009 and revealed its lighting plan for the mine, another group joined the fray: the International Dark-Sky Assn. and the numerous astronomers whose research and livelihoods depend on the desert’s dark skies.

“The [mine's] impact on astronomy is potentially very, very significant,” said Scott Kardel, public affairs director of the association, a Tucson-based nonprofit that has worked to preserve and protect the darkness of night skies since 1988.

Because the mine would operate 24 hours a day, seven days a week, nighttime floodlights required by federal safety requirements could create significant light pollution that would interfere with astronomy.

The site of the proposed Rosemont Copper Mine is 12 miles northeast of the Fred Lawrence Whipple Observatory, known for its Multiple Mirror Telescope and work in ground-based gamma-ray astronomy.

“The initial lighting estimate of the [mine's] light output was very bad,” said Emilio Falco, project director at the Whipple Observatory, which is part of the Harvard-Smithsonian Center for Astrophysics.

According to that initial estimate, the mine’s lumen output the measure of the amount of visible light emitted by a source would be 21.7 million lumens, or the equivalent of about 12,000 houses.

The scientific community and the industries that cater to the astronomers were alarmed. In 2007, a study conducted by the University of Arizona estimated that astronomy contributed $250 million annually to the state’s economy.

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