ALBUQUERQUE - A battle is brewing over how to best protect groundwater at mining sites around New Mexico.

The state Environment Department said last week that the rules it has proposed would be the most stringent of any copper producing state in the West, including Arizona, Nevada and Utah. They include new engineering requirements for handling left-over rock, leach piles, tanks and pipelines.

"This idea that we've somehow lowered our standards or created a safe haven for polluters is completely untrue," said Ryan Flynn, general counsel for the department. "We've actually raised the bar."

The proposed rules have the support of New Mexico's copper mining industry, but environmentalists argue that the state stands to take a step back if the rules are approved by the state's Water Quality Control Commission.

Environmentalists accuse the department of giving in to the industry despite months of stakeholder meetings. Attorney General Gary King has also come out in opposition, saying the proposed rules would violate state water protection laws.

"For 35 years, the law of the land in New Mexico has been you protect groundwater quality. Now, what will be happening is mining companies get to use groundwater as essentially a dumping ground. They don't have to prevent pollution," said Allyson Siwik of the Silver City-based Gila Resources Information Project.

The water commission has begun what is expected to be a monthlong hearing. A final decision isn't likely until the summer, and experts say legal action will likely follow.

The proposed rules stem from legislation approved in 2009 that sought more consistent rules for regulating groundwater affected by copper mining. Last year, mining representatives, state environment officials and environmental groups attended nearly two dozen meetings to discuss the rules and the department hired an independent contractor to develop a draft.

Flynn said most of the contractor's proposal was adopted, but environmentalists argue that the final version submitted to the water commission includes most of the comments that were submitted by Phoenix-based mining giant Freeport McMoRan, which operates several copper mines in New Mexico and Arizona.

Critics of the proposed rules say earlier versions required liners to be installed in certain areas. Under the version being considered by the commission, liners would be required at the discretion of the department when it considers granting permits or renewing permits.

Past court rulings have called into question the ability of the Environment Department to require water under mining operations to meet drinkable standards, Flynn said.


Like New Mexico, the Arizona Department of Environmental Quality doesn't routinely require liners to prevent groundwater pollution from new copper mines.

Instead, ADEQ requires all new mines to produce the best available demonstrated control technology to get a permit allowing them to operate and showing they aren't likely to contaminate groundwater through their mine tailings.

For copper mines and precious metals such as gold, a mining company can use a system combining a synthetic liner with a less permeable soil layer lying below to keep pollutants from seeping underground.

Typically, when a mining company designs a tailings impoundment system, the department must evaluate the mine's climate and surface water controls, subsurface conditions, the mine's operational practices and engineering controls including drains, under drains and hydraulic barriers, said Mark Shaffer, an ADEQ spokesman.

When the department gave Rosemont Copper an aquifer protection permit last year for its proposed Rosemont Mine southeast of Tucson, it didn't require a liner in part because department officials believed that the mine's dry stack tailings won't allow much seepage of pollutants underground. The company also will employ "a heavy dose of stormwater control" to keep runoff from entering the site, Shaffer said.

Opponents of the mine, however, said that the mine won't be able to prevent pollution of the aquifer because they believe enough runoff will seep through the tailings, given that this area's rainfall exceeds the 11 inches that typically falls annually in Tucson.

The opponents were willing to consider running drainage pipelines under the tailings to keep runoff away, "but they (company officials) didn't want to do that," said Greg Shinsky, a Rosemont opponent who lives near Arizona 83, north of the proposed mine site in the Santa Rita Mountains.

Tony Davis, Arizona Daily Star

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