Regulators counter that the state has the toughest rules in the West.
After years of legal wrangling, both sides made their points Wednesday in arguments to the New Mexico Supreme Court, but it’s unclear how long it could take for a decision to be issued.
Environmentalists want the court to require the state to adopt new regulations to prevent pollution.
The state Water Quality Act requires regulations that prevent or abate pollution, but the rules in place specifically allow the copper mining industry to pollute groundwater, said Doug Meiklejohn, an attorney and executive director of the New Mexico Environmental Law Center.
Upholding the most basic premise of the law makes sense because the majority of New Mexicans depend on groundwater sources for their drinking water, he said.
The New Mexico Environment Department has long argued that the regulations are among the most stringent of any copper-producing state in the West and strike a balance between protecting water and allowing economic development.
The Legislature amended the act in 2009 to allow the Water Quality Control Commission to adopt regulations involving the copper industry to prevent water pollution and monitor water quality.
Environment Secretary Butch Tongate called the previous rule outdated and inconsistent.
“Opponents of the copper rule would prefer to shut down mining in New Mexico — destroying jobs and devastating communities — than offer support for the copper rule,” Tongate said in a statement.
He pointed to a previous decision by an appeals court that upheld the rule, which includes engineering requirements for handling leftover rock, leach piles, tanks and pipelines.
Watchdog groups and Ted Turner’s Ladder Ranch had argued that the regulations give mining companies too much leeway to pollute. In 2015, the appellate court ruled those claims were unfounded.
Opponents had also complained that the crafting of the rules was influenced by the mining industry. State officials disputed that claim.
Southwestern New Mexico is home to three copper mines owned by Freeport McMoRan, the world’s largest publicly traded copper producer. In 2015, the company’s New Mexico operations generated an estimated $176 million in economic benefits for Grant County and about $422 million for the state overall.
The mines in the Silver City area employ more than 1,400 people.
Company officials said they are better able to plan for future investments and operations because the rule applies consistent standards for preventing or managing the effects of mining on groundwater.