A state rule to protect groundwater from copper mine pollution will stand.

The New Mexico Supreme Court affirmed the rule Thursday and rejected arguments from environmental groups and the New Mexico Office of the Attorney General that the rule violated the state’s Water Quality Act.

In the court’s unanimous opinion, justices sided with the New Mexico Environment Department and the mining industry to uphold the 2013 copper rule.

Chief Justice Judith Nakamura wrote that the rule contains an “abundance of provisions that afford significant groundwater protection at copper mine facilities designed to prevent pollution.” She added that the court was tasked with deciding whether the rule violated state statute, not determining how to prevent groundwater contamination from open pit copper mining.

“We are pleased that the New Mexico Supreme Court has upheld the state’s Copper Rule today, affirming its validity,” New Mexico Environment Department (NMED) Secretary Butch Tongate said in a statement. “Since its adoption, the New Mexico Environment Department has been successfully implementing the Copper Rule, one of the most stringent and effective environmental regulations in the country, and we will continue to do so in light of the Supreme Court’s opinion.”

Eric Kinneberg, director of external communications for Freeport-McMoRan, Inc. (FMI) noted that the rule “establishes clear and stringent, but reasonable, requirements for copper mines to protect the quality of New Mexico’s water resources.” FMI owns three copper mines in the state.

Kinneberg also said the rule provides greater regulatory certainty for the company’s copper mines and its employees. The rule was developed by NMED through a stakeholder process, he said, which included technical experts, industry representatives and environmental interests. “The rule was adopted by the Commission after a lengthy public hearing where the technical evidence in support of the rule, as well as opposing views, were presented,” Kinneberg said. “We thank the Department and the Commission for their hard work to develop, consider and adopt these very important rules.”

For five years, the New Mexico Office of the Attorney General and groups represented by the New Mexico Environmental Law Center challenged the rule, claiming it violated the state’s Water Quality Act by allowing pollution from copper mines to exceed state standards.

New Mexico Environmental Law Center Executive Director Douglas Meiklejohn was disappointed by Thursday’s ruling.

“We do not think, based on the opinion, that the court understood the realities of groundwater contamination,” he told NM Political Report. “The court’s view of how possible it is to contain pollution in groundwater seems to us to be unrealistic, and we disagree with the court’s interpretation of the Water Quality Act.”

During oral arguments in the fall of 2016, the rule’s opponents claimed it exempted all open pit copper mines from strict regulations, rather than requiring the state to evaluate each mine on a case-by-case basis, as it had in the past.

“Allowing copper mines to pollute our public water supplies may only be the tip of the iceberg,” said Rachel Conn, projects director with Amigos Bravos, who added that the decision could “pave the way” for other facilities, including national laboratories and wastewater treatment plants, to pollute groundwater beneath their sites, and then leave New Mexico taxpayers with the cleanup bills.

“This idea of ‘strategic containment’ is in direct opposition of the New Mexico Water Quality Act’s purpose of preventing and abating water ​pollution,” said Conn, whose group was among those represented by the New Mexico Environmental Law Center. “The court’s decision allows for new mines to be permitted under the presumption that they will pollute our state’s water resources.”

Allyson Siwik, executive director of Silver City-based Gila Resources Information Project, was also disappointed. “The Supreme Court has effectively sanctioned the idea of groundwater sacrifice zones in the area of copper mines,” said Siwik, whose group also challenged the rule. “In Grant County, we are 100% dependent upon our groundwater aquifer. Allowing Freeport-McMoRan to pollute rather than prevent groundwater contamination threatens our drinking water supply over the long term.”

In response to Thursday’s court ruling, the Attorney General’s spokesman, James Hallinan emailed a statement: “The Office of the Attorney General is glad the Supreme Court ruled on this important matter and we will continue to enforce clean water standards to protect New Mexico families and small businesses.”

In 2009, the New Mexico Legislature directed the state’s Water Quality Control Commission to develop new groundwater rules for the dairy industry and copper mines.

For seven months, a copper advisory committee and a technical committee worked to draft a rule that would regulate groundwater quality and cleanup beneath copper mines. When that draft was complete, it was sent for approval to NMED. Before the rule was released to the public, NMED’s then-general counsel, Ryan Flynn, made changes that activists say favored earlier requests made by FMI and rejected by other stakeholders. The Attorney General’s Office, under Gary King, and environmental groups pushed back against the Water Quality Control Commission’s adoption of the rule and sued to have it overturned, but the New Mexico Court of Appeals sided with the state.

Gov. Susana Martinez appointed Flynn as NMED Secretary. He later left the state agency to head the New Mexico Oil and Gas Association.