Pima County issued a violation notice to Freeport McMoRan mining company last week after dozens of Green Valley residents reported clouds of tailings dust coming from the Sierrita Mine on Jan. 9. The notice comes six months after Freeport paid $230,000 to settle a series of repeated air quality violations in 2018. This marks the company’s fifth notice of violation since 2017.
According to the Pima County Department of Environmental Quality, Freeport allowed visible dust emissions to cross the property boundary Jan. 9. The company’s permit states that visible emissions from dust sources are not to exceed 20% opacity, but the PDEQ inspector measured the opacity at 39.6% between 2:40 p.m. and 2:49 p.m.
Mine tailings are a finely ground residue or dust that is generated from mining operations. Just like normal dust, excessive exposure to tailings can provoke or aggravate symptoms of asthma, bronchitis or other respiratory issues.
“We live in a cul-de-sac and it was recently seal coated, so it was really dark black. But on that day, it was completely white,” said Green Valley resident Mark Lamberton. “And our garage is not sealed, so everything in our garage was covered with white dust and you track it in the house and it makes us cough and sneeze.”
Lamberton was one of 10 residents who contacted PDEQ that day, as well as nearly 30 others who made official complaints to Freeport directly.
According to Lamberton and other residents, the dust from the mine is difficult to clean and has become a slipping hazard, especially for older residents.
“I’m really hoping that they’ll improve the dust control because it’s a huge issue for those of us who live down wind,” he said. “It’s really difficult to clean because it’s really fine dust, so we can’t wipe it with a dry rag and a wet rag turns it into a muddy mess.”
Freeport’s last violation notice claims the company failed to control dust emissions on nine different occasions between Sept. 20 and Nov. 8, 2018. As a result, the company gave $200,000 to help build a 2-mile walking path at Green Valley’s new county park and paid a $30,000 fine. The company also spent an additional $200,000 to help about 800 residents clean their homes.
According to Ursula Nelson, PDEQ director, the county is working with Freeport to help correct the issues. The company may face enhanced penalties because another violation happened so quickly.
“I understand the concerns that residents have,” she said. “While I haven’t experienced it myself, I’ve seen pictures of the dust and it certainly does have an impact on the community.”
According to Nelson, Freeport self-reported the dust event Jan. 9. In a statement released by company spokeswoman Linda Hayes on Jan. 10, she said the mine experienced sustained winds of over 25 mph and that mine employees reacted quickly to apply a dust suppressant to the tailings impoundment.
The company is also allegedly developing new ways to control the dust.
“We think they’ve been really aggressive in looking at different technologies and different ways to reduce the amount of dust that they’re creating,” Nelson said. “That certainly does not excuse a violation, but it’s good to see that they are doing things and showing that they are trying to find better ways of doing things.”
The company, Nelson said, is looking at different types of materials that they can apply to the surface of the tailings that may be more effective at holding the dust down.
Freeport has also been working with satellite imaging to analyze the mining area and find dry patches that might be more susceptible to wind.
Freeport has until Feb. 24 to submit a written response to the county that details the actions that led to the violation and any corrective actions that they’ve taken or plan to take to meet compliance.
