Conservationists are asking Nevada's Environmental Commission to rescind a state water permit for a mining project they say would create one of the largest open-pit operations in the country and could pollute Nevada's groundwater for hundreds of years.
The Great Basin Resource Watch plans to argue its appeal Wednesday in Carson City.
The Reno-based group and others have been fighting in federal court since 2012 to block the molybdenum mine that a subsidiary of the Denver-based General Moly Inc. wants to build 250 miles (402 kilometers) east of Reno.
It says the state water pollution control permit granted last year is based on a flawed computer model that underestimates the toxic threat to public health and the environment.
Molybdenum is a metal with a high melting point used to refine oil and make electrodes, missile and aircraft parts.
