By Scott Sonner
Associated Press

CARSON CITY — Nevada’s Environmental Commission rejected conservationists’ appeal last Wednesday of a water pollution control permit granted last year for a huge open-pit mine critics warn could pollute the state’s precious groundwater for centuries.

The Great Basin Resource Watch had urged the state panel to rescind the permit for a molybdenum (muh-LIB’-duhnuhm) mine that a subsidiary of Denver-based General Moly Inc. wants to dig on Mount Hope near Eureka about 250 miles (400 kilometers) east of Reno.

Scientific experts for the Reno-based environmental watchdog testified Wednesday that the permit was based on a flawed calculation that dramatically underestimates the amount of contamination that will flow into the mile-wide (1.6 kilometer-wide) pit when mining is complete and it begins to fill with water.

The commissioners upheld the permit on a 3-0 vote after more than eight hours of testimony.

But they also issued a special directive for the Nevada Division of Environmental Protection to work with the group to address its ongoing concerns, as well as discuss potential changes to state laws or regulations to better protect water quality in the pit lakes after mining ends.

Molybdenum is a metal with a high melting point used to refine oil and make electrodes, missile and aircraft parts.

The Great Basin Resource Watch and others have been fighting in federal court since 2012 to block Eureka Moly LLC’s plans to build the mine covering about 12 square miles (31 square kilometers).

The mining operation is expected to last 44 years but there’s no current projection for when it might begin. It’s expected to produce 1.7 billion tons of waste rock, about one-fourth of it considered potential acid-generating material.

Glenn Miller, a retired professor who taught environmental sciences for 40 years at the University of Nevada, Reno and now serves on the watchdog group’s board, said the company has “grossly” underestimated the amount of acid drainage that will send sulfates into the pit lake he says will last for 500 years.

“Their prediction is hopelessly unrealistic,” he said. “It’s just not even in the realm of possibility.”