mine dust

Tailings dust fills the air over Green Valley on Oct. 6.

Nearly a year after Green Valley residents were inundated with several inches of mine dust over several months, Freeport-McMoran is close to making a deal with Pima County that would put money toward the community's new county park.

Nothing has been signed yet, but Freeport has tentatively agreed to cover some of the costs associated with turning the closed 130-acre Canoa Hills golf course into a natural, open-space park, said Beth Gorman, a spokeswoman with the Pima County Department of Environmental Quality.

"Freeport has not contested that there were violations of fugitive dust regulation and, as a result, the discussions have progressed to the penalty stage and these discussions include a supplemental environmental project that will benefit the community," Gorman said Friday.

Gorman said she was hesitant to discuss details of the deal, and said the site of the environmental project and associated costs weren't settled.

 "We feel fairly confident nothing is going to change, but it could," she said. 

Linda Hayes, a spokeswoman for Freeport, declined comment Friday because the agreement hasn’t been finalized.

But she said via email Friday that, “we have been working collaboratively with the county to ensure that the community impacted by the dust events will benefit from any proposed agreement.”

Hundreds of Green Valley residents reported being inundated by dust from the Sierrita Mine in early October. Some compared the thick dust clouds to snowstorms; layers of dust were found inside homes and medical issues were reported. In November, dust swept past the mine's boundaries again.

The PDEQ sent two Notice of Violation letters to Freeport about the incidents. In each, officials said the company allowed mine dust to escape the boundaries on eight days in September, October and November. They also alleged the company allowed its visible emissions to exceed the 20 percent limit. At one point, it reached 63 percent opacity, according to the county.

The county informed the company it was evaluating a civil penalty for the violations that resulted in both notices. In February, Hayes said the company had assisted about 800 residents in getting their homes cleaned at a cost of more than $200,000.

David Rhoades, general manager of Freeport's Sierrita operation, responded to the Notices of Violation with nearly identical letters Dec. 14 and Jan. 30. In each, he explained that wetting the tailings dam with water and magnesium chloride have “largely proven effective,” but because of the size of the dam, weather conditions and high wind events can overwhelm those measures.

In the December letter, Rhodes said the tailings dam was damaged by what he called a “six-hour, 500-year storm event,” and that sustained high winds caused the October dust events. He cited NOAA — the National Oceanic and Atmospheric Administration — for the 500-year figure.

In his Jan. 30 letter, Rhoades said his crews attempted to prepare for high winds forecasted by the National Weather Service prior to the Nov. 13 and Nov. 29 wind events. A week prior, his crews applied 102,000 gallons of magnesium chloride and 1.1 million gallons of water on the tailings. In addition, he said they applied 96,750 gallons of magnesium chloride and 851,000 gallons of water in advance of the Nov. 29 event.

In the month prior to the Oct. 6 and Oct. 7 high-wind events, Rhoades said his crews applied 78,750 gallons of magnesium chloride but that it had lost its binding properties due to what he called the 500-year storm.

In the January letter, Rhoades said the company was investigating the possibility of applying magnesium chloride from the air. They need to determine how effective and expensive it would be, which airport the plane would depart from, if the airport would allow the material to be stored on site, and how corrosive the material would be to airplanes.

Rhoades also said that during the Nov. 29 dust event, the all-terrain vehicles couldn’t get to a dried-out area of the tailings because of a pond and the possibility of getting stuck. As a result of that incident, the crews will reduce their loads and having a spotter walk in front of the vehicles to detect areas that are too soft to drive on, he wrote.

In Friday’s email, Hayes wrote, “Regarding dust control measures, we have purchased additional equipment and added a crew dedicated solely to dust control efforts. This includes applying dust suppressant by hand, if necessary.”

Park property

The defunct 130-acre Canoa Hills golf course was signed over to Pima County on Dec. 21 with the intention of making it a natural, open-space park. It was donated by businessman Morgan North, and does not yet have a name. 

The golf course closed in 2013, and was purchased by North a year later along with San Ignacio golf course. North, who owns Borderland Construction, a civil contracting business, never reopened Canoa Hills.

This wouldn't be the first time mine money helped local projects. 

In 2009, Freeport agreed to a $105,000 fine for air-quality violations. More than half of the funds, $60,000, was used to help purchase a diesel-electric hybrid school bus for the Sahuarita Unified School District.

The agreement stemmed from complaints from Green Valley residents in August and September 2006 about excessive dust emissions from the tailings impoundment at the Sierrita facility. Freeport spent more than $170,000 to clean more than 600 homes after the dust events in 2006.

In 2013, Asarco agreed to pay a $40,000 fine to Pima County and $30,000 toward bike paths in Tucson because of air quality violations. In addition, the company sent semi-annual newsletters to the Rancho Resort Association and the town for two years. Asarco also agreed to annual tours of the mine to the Rancho Resort Association and the Town Council during those two years.

In December 2010, Asarco agreed to a $100,000 fine to Pima County and to provide $350,000 for three environmental projects at the county’s Canoa Conservation Park for mine tailings dust that came off its Mission Mine and into homes and yards in Rancho Resort.

Kim Smith | 520-547-9740

Assistant Editor Kim Smith moved to Arizona from Michigan when she was 16. She graduated from the University of Arizona with a degree in journalism in 1989. She has worked at seven newspapers of varying size in Arizona, Texas and Nevada.

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