The Nevada Division of Environmental Protection is planning to investigate questions raised by two environmental groups regarding groundwater quality at Cortez Gold Mines operations southwest of Carlin.
"I'm not aware of any groundwater problems," the division's Deputy Administrator Leo Drozdoff said, but he added that agency will look into the concerns and provide answers to questions raised in the complaint.
"Essentially, Great Basin Mine Watch and the Western Shoshone Defense Project are requesting that the Division of Environmental Protection investigate various questions regarding the Pipeline Project," Drozdoff said.
The two groups are alleging that Cortez is contaminating groundwater with extra salt and nitrates picked up as water infiltrates back into the ground.
Nicole Rinke, an attorney for the Western Mining Action Project who filed the request for investigation with the state for the two environmental groups, said state law prohibits degradation of groundwater.
"That NDEP has been permitting this for years is illegal and illogical," Rinke said.
According to the two groups, water Cortez infiltrates back into the ground after dewatering the Pipeline and South Pipeline open pits contains levels of salt and nitrates that are up to six times higher than the drinking water standard.
Cortez's senior dewatering engineer, George Fennemore, told the Elko Daily Free Press that while the groundwater quality is good, monitoring wells above the gravel at infiltration ponds show water with too much salt and nitrates because the water hasn't filtered through layers of gravel.
"We've gone through this a number of times with NDEP. It comes down to protecting future use. To date, we've been able to protect the groundwater," Fennemore said.
Cortez dewaters 21,000 gallons per minute to keep the Pipeline and South Pipeline open pits dry for mining, and the pumped water goes to 10 infiltration basins or is used for irrigation, the Free Press reported.