Six months after Freeport-McMoran reached a settlement with Pima County over several mine dust violations, the county has again accused the mine company of violating its air quality operating permit.
The Pima County Department of Environmental Quality sent Freeport general manager David Rhoades a Notice of Violation on Friday.
The notice alleges fugitive dust crossed the Sierrita Mine’s property boundary Jan. 9, and the company allowed visible dust emissions from the tailing impoundments to be over the 20% opacity restriction in its permit. The county alleges the opacity was measured at 39.6% at that location between 2:40 p.m. and 2:49 p.m. that day.
According to the notice, Freeport now has 30 calendar days to submit a written response to the county that must include a “thorough explanation” of the actions that led to the violations, corrective actions to meet compliance and corrective measures that have been taken to prevent future violations.
PDEQ employees received 10 calls about the dust Jan. 9, and a PDEQ inspector who happened to be in the area immediately went to the mine to investigate, said Beth Gorman, a PDEQ spokeswoman.
The last time Freeport was issued a Notice of Violation, the company was accused of violating its air quality operating permit on nine occasions at the Sierrita Mine between Sept. 20 and Nov. 8, 2018. It took more than a month for the county to investigate and issue the notice.
This time it only took 15 days because the inspector was able to respond quickly, take photographs, make observations, go on the property and obtain evidence, Gorman said. In addition, this dust event took place during a single day.
Gorman said there is a chance Freeport will face enhanced penalties because the violation happened again so quickly, but that will be determined after reviewing the requested documents from the company.
Gorman said Freeport self-reported the Jan. 9 dust event and is in the process of evaluating different methods to control dust from the tailings as well as additional ways to monitor the tailings.
Asked if the county is concerned it has had to issue another notice so quickly after the last one, Gorman said, “PDEQ is always concerned when there are violations of permit conditions. PDEQ works with all our regulated companies to ensure compliance and we take appropriate action when there are violations.”
While some may believe those living near the mine should expect dust to escape the property, Gorman said the county doesn’t think it’s just a fact of life.
“We will work with Freeport to address the current situation and evaluate what if any additional actions can be taken to prevent this from happening,” she said.
In July, Freeport agreed to contribute $200,000 to build a two-mile walking path at Green Valley’s new county park as part of a settlement reached over the mine dust violations in 2018.
In addition to creating the walking path at Canoa Hills Trails – An Open Space Park, the mining company also paid a $30,000 civil penalty because of the 2018 violations.
In an email Tuesday afternoon, Freeport spokesman Linda Hayes said, “We will be reviewing the Notice of Violation and will work cooperatively with PDEQ to address the concerns outlined. Sierrita Operations remains committed to responsible dust management and continues to evaluate opportunities to improve our system.”
On Jan. 10, she released a statement stating the mine experienced sustained winds of more than 25 mph and mine employees reacted quickly to apply a dust suppressant to the tailings impoundment.
She said anybody affected should contact the Sierrita Operations 24-Hour Community Information Line at 520-393-4426.
When Pima County issued Notices of Violation to Freeport in 2018, Rhoades responded with nearly identical letters. 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.
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Kim Smith | 520-547-9740
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•Sept. 20 — Nov. 8, 2018: Freeport McMoRan’s Sierrita Mine accused of violating air quality permit on nine occasions.
•Oct. 2, 2017: Freeport self-reported a dust event; there was no fine.
•Jan. 31, 2016: Freeport is issued an Opportunity to Correct after a complaint about “fugitive dust” leaving mine property. Freeport also reported the event.
•July 27, 2013: Freeport’s Sierrita operation was issued a Notice of Violation after a cloud of tailings dust rolled off the mine and across Green Valley, leaving a film on homes, patios and vehicles, and caused a brief but heavy spike in air quality measurements. The mine said the crust on the tailings had been compromised by heavy rain a day earlier.
•Aug. 27, 2013: Freeport received a Notice of Violation for an air quality infraction and agreed to pay a civil penalty of $35,000.
•2013: Asarco, which operates the Mission Mine west of Sahuarita, agreed to pay $70,000 in a settlement tied to three dust violations in 2012-13.
•2009-10: Asarco agreed to pay a $100,000 fine after dust came off its Mission Mine and into the homes and yards of Sahuarita residents. It also paid $350,000 toward three county environmental projects. The payments were part of a settlement with PDEQ following three dust incidents in late 2009 and early 2010.
•2006: Freeport-McMoRan agreed to a $105,000 fine in 2009 related to air-quality violations that occurred in August and September 2006 at the Sierrita mine.