Activity at Arizona's mines is surging, and so is the release of toxic materials.
A new Environmental Protection Agency report shows that releases of mine tailings and other toxic emissions increased 22 percent in Arizona in 2011 - and that's on top of a 31 percent increase in 2010.
Arizona's increases were far bigger, percentagewise, than those recorded nationally. Mining and metals production and processing are by far the biggest sources of those releases in Arizona and nationally.
The EPA report, known as the Toxic Release Inventory, documents how many pounds of chemicals and heavy metals industries release into air, water and onto the ground. The reports, based on information the EPA gets from industries, show that the levels of toxic materials released are far less than they were in 2000, but still on the rise.
The increases are more than a visual blight to neighbors like Kay Davin, who says that when high winds blow down Helmet Peak Road from the tailings piles at Asarco's Mission Mine Complex, all she can see from her house are huge, grayish dust clouds. Since a big dust storm blew tailings dust into her and her neighbors' homes in Sahuarita's Rancho Resort more than three years ago, she's had to use oxygen to breathe late at night, she says.
The Asarco tailings have prompted Pima County to issue two violation notices to the mine in the past two months after dust storms in December and January blew tailings into the area where Davin lives. That came three years after that 2009 dust storm triggered a county order for Asarco to pay $450,000 in penalties and for environmental programs.
The EPA emphasizes that not all toxic releases detailed in the report necessarily hurt people. Data in the report isn't enough to determine exposure to these compounds, the EPA says.
In Southern Arizona, for one, it's not the metal toxins in mine tailings that have Asarco's Sahuarita neighbors agitated and health experts concerned. The Mission Mine tailings' fine particles, which can lodge in lungs, pose a bigger health risk, scientists say. But concentrations of particulates in mine tailings don't have to be reported to the EPA.
Asarco has taken steps over the years to reduce the problem and says it will continue to do so. Like most mining companies, it is developing more sophisticated technologies to manage tailings. At Mission, for example, Asarco is putting a soil cap atop the tailings pile that apparently has caused neighbors the most grief, and won't use it anymore.
Hayden Smelter a big source
Of nearly 98 million pounds of Arizona toxic releases reported to the EPA for 2011, 86 percent came from mines and primary metals businesses, which are involved in metals manufacturing, processing and refining.
In 2010 and 2011, the biggest source of toxic releases was Asarco's Hayden smelter and concentrator complex, nearly 100 miles north of Tucson. In 2011, Hayden released 44 million pounds.
Of the top 10 Arizona releasers of toxic materials in 2010 and 2011, seven were from mining or metals facilities, including the Mission Complex and Freeport-McMoRan Copper and Gold's Sierrita Mine near Green Valley. Nationally, mining and metals businesses are also the biggest toxic release sources, together exceeding half of all 2011 toxic releases, EPA records show.
The primary sources of these releases are waste rock, which is removed to get at valuable mine deposits, and tailings. Tailings are a slurry of fine-grained rock and water that's left over after mineral ore goes through floatation and milling to produce concentrates to be sent to market.
At Freeport's Sierrita Mine, 65 percent of reported toxic releases were metal compounds in tailings, 33 percent were lead and mercury compounds in waste rock, and 2 percent were releases to air, the company said in a statement. At its Morenci mine, one of the country's largest copper mines, 93 percent of releases were tailings, Freeport said.
At Asarco's Hayden smelter and concentrator, the releases include tailings from ore, from the processing of slag in the concentrator and the disposal of the smelter's slag, Asarco vice president Tom Aldrich said in a statement.
Some report lower releases
Not all of Arizona's big mines are reporting higher releases. Those at Sierrita and Freeport's Miami operation reported declines in 2011, due to changes in releases from the mill at Sierrita and to normal variation in smelter operations at Miami, Freeport said in a statement.
The Morenci Mine's releases rose 61 percent, due to higher releases of metals from worn mill liners and grinder balls due to the mine's increased operations, the company said. Increased production, stemming from continued high copper prices, also caused more toxic releases from Asarco's mines and Hayden smelter. But the bigger cause is that different areas of its ore bodies have different metals, Aldrich said.
"It's the nature of the ore body," he said
Statewide, all mining companies together reported releasing at least 100,000 pounds in 2011 of 13 metals and other toxic compounds, including copper, lead, arsenic, antimony, barium, chromium, nickel and sulfuric acid.
Yet despite these recent increases, Arizona's total toxic releases remain well below levels of the late 1990s and early 2000s. Those high levels occurred before BHP's San Manuel Mine and smelter shut down around that time, and the economic slump of 2001-03 caused other Arizona mines to sharply cut back operations.
Dust particles a concern
Many Southern Arizona environmentalists say they're not that concerned about the toxins in the waste rock because those materials are largely inert - although they're not happy at the waste rock's presence on the landscape.
The threat isn't that serious from traditional toxins such as heavy metals in tailings at the two Tucson-area mines, scientists say. Research conducted by Freeport at Sierrita and by University of Arizona scientists at Mission has found the tailings' concentrations of metals are no greater than in the surrounding, native desert soil.
At Asarco's Mission complex, however, UA researchers found up to twice as many of the small and very small particles in tailings samples collected from a Sahuarita patio after the 2009 dust storm.
"This is a concern since the smaller tailing dust particles get deeper into the lungs and potentially cause more health concerns than the larger, airborne particles from background soil," Pima County Department of Environmental Quality Director Ursula Kramer wrote in a 2010 memo.
One reason the particles are so small is that mining technology has gotten more efficient at using metals and finely crushing ores, said Raina Maier, director of the UA's Superfund research program.
"If you have big wind events and the mine tailings are blown and people breathe them in, they can exacerbate existing health issues, such as asthma or chronic pulmonary disease," Maier said.
Trying to control dust
Mining companies are developing more sophisticated technologies to manage their tailings and reduce windblown dust, Maier said. That includes spraying additives onto tailings to create a crust that's less likely to blow off, which Asarco has done at Mission.
"They take weather forecasting models into account when they decide how and when to wet the tailings," Maier said. "It's smart technology. I've talked to people at Asarco and Freeport and dust is a big issue for them and controlling it is hard."
At Freeport's Sierrita Mine, the company sprays tailings with water and dust suppressant compounds. It caps roads in the tailings area with native soil and restricts vehicle traffic and speeds.
It also revegetates side slopes of tailings to minimize erosion from wind and rain. Nancy Freeman, a Green Valley activist, said the mine used to have chronic tailings dust problems but has had no major problems in the past two years.
As for Asarco, since 2009, it has sprayed the chemical additives onto Mission's tailings, and changed how it builds up earthen berms at tailings facilities to reduce the amount of area it leaves dry at a given time, its vice president Aldrich said. It has started inspecting tailings monthly.
But when dust clouds started blowing from the Mission site on Dec. 14 of last year and Jan. 10 of this year, Asarco reported to Pima County that excessive tailings were blowing from tailings Pile No. 8. That one produced many of the dust problems in 2009.
Both times, the county said tailings left Asarco's property, in violation of county laws. In the December incident, county inspectors said tailings dust was about 84 percent opaque, or cloudy, compared to a 20 percent legal limit.
"We could see the cloud running all the way up north on Interstate 19 to I-10," Jack Belove, a Rancho Resort resident, said of the tailings. "We can't live with this. It's going to kill our lungs."
His wife, Eileen, said that although they weren't as bad as in 2009, these dust storms blew tailings into yards, covered fruit trees and piled up at door entrances - as in 2009.
"There are seven schools in this Sahuarita area, and how unfair it is to subject babies to a whole lifetime of this," Eileen said.
Since those events, Asarco has decided to stop piling new tailings onto No. 8. It has contractors working 12 hours daily, seven days a week, capping the pile, which was nearing the end of its expected life, Aldrich said. The work should be finished in March, he said.
"We want to be a good neighbor and we think we've been a good neighbor over there," Aldrich said. "We have at least 20 more years of mining life at that facility and we want to make sure we have good relationships with people all around us."
County officials are discussing the new violations with Asarco. It's not known if more fines are coming, PDEQ director Kramer said.
For now, the tailings have grown frighteningly tall, more than doubling in height since she and her husband moved here in 2002, said Kay Davin.
"When we moved here, the tailings were no higher than the fence down the street," Davin said. "Now, they are so high you can't see the sunset."
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Problems caused by toxic releases
The release of tailings and other toxic materials from mining companies in Southern Arizona has been tied to environmental problems:
• Tailings have seeped into groundwater underneath the Freeport-McMoRan Sierrita mine site, tainting two Green Valley wells with sulfates. Freeport has paid to replace the wells. The company is pumping contaminated water away from that area.
Sulfates aren't dangerous for most people to drink, but they sometimes can trigger or aggravate diarrhea, the EPA has said.
• At Asarco's Hayden smelter and concentrator sites, the Environmental Protection Agency in November 2011 issued a violation notice accusing the smelter of emitting levels of arsenic, lead and other dangerous compounds that exceeded federal standards. Asarco is contesting the charges.
John Hillenbrand, EPA's project manager for the Hayden site, said Asarco has sprayed those tailings with dust-suppression compounds.
"We want to be a good neighbor and we think we've been a good neighbor over there. We have at least 20 more years of mining life at that facility (Mission mine near Sahuarita) and we want to make sure we have good relationships with people all around us."
Asarco vice president
Contact Tony Davis at email@example.com or 806-7746.