By CAROL RYAN DUMAS
Capital Press

Monsanto's biggest challenge at its Idaho phosphate mining operation has been in lowering levels of selenium at the point of discharge into waters.

That's been a learning curve, since selenium wasn't monitored or even on worried about as a contaminant before the late 1990s, said Trent Clark, Monsanto's director of public and governmental affairs.

The company has put five years and $6.5 million into studies addressing selenium management and is confident the design for its proposed Blackfoot Bridge mine is more than adequate.

The company mines phosphorous ore and processes it into glyphosate, an agricultural herbicide. Mining digs up selenium-bearing rock, which is put in overburden piles alongside the mine and later backfilled into the pit. When selenium is oxidized through air or water, it can leach into surface or groundwater.

The company has developed a capping system that prevents water from coming in contact with selenium from on top or underneath, Clark said.

The new mine "will be the most environmentally advanced in North America, with an advanced capping system," Clark said. "It's really over-engineered to be protective for the environment."

Jeff Kundick, BLM minerals branch chief, said "some of these management practices are state of the art, somewhat unprecedented."

About half of the mine will be lower than the groundwater table, so some of that water will enter the mine. He said the mine will have to be managed so there's little or no impact on surface water or groundwater above allowable levels.

"We've told Monsanto that any predicted water discharged to the Blackfoot River - surfaces or springs - have got to be below 5 parts per billion," Kundick said. "Thus, they've had to come in with this very costly geosynthetic liner. They've been pretty cooperative so far."

Water-quality standards - developed after horses and sheep in southeastern Idaho were found dead from selenium poisoning in the late 1990s - set selenium levels in waters discharged into the environment at no more than 5 parts per billion. Drinking water standards are at 50 ppb.

The Environmental Protection Agency has had a long regulatory relationship with Monsanto to bring the company into compliance with the Clean Water Act, said Eva DeMaria, EPA's Region 10 National Pollutant Discharge Elimination Permit coordinator.

"We have sent them notices of violation about their discharges and we have expressed our concerns about discharges at the Horseshoe Dump numerous times," she said. "They have had unpermitted discharges of seepage originating at Horseshoe Dump entering an unnamed tributary that goes into Sheep Creek."

The discharges occurred primarily during spring melt, she said.

EPA's notices of violation followed big rain events and Monsanto's management was called into question. The response was to increase the size of a pond or install additional pumping, Clark said.

DeMaria said Monsanto has been "responsive" to all notices and requests for information from EPA.

"Some of the notices of violation were merely the beginning of discussions with EPA to make sure our selenium control systems were in place," Clark said. "That's some of the learning that happened after selenium arose" as an issue, he said.

Selenium concerns are addressed at the Blackfoot Bridge site, he said. If Monsanto had known then what it knows now, It would have designed the Horseshoe Dump catch system the way it designed the Blackfoot Bridge system.

"If I sound skeptical, I am," said Marv Hoyt, Idaho director for Greater Yellowstone Coalition.

The environmental community has received assurances from resource agencies in the past that one proposal after another will prevent water contamination, he said.

"Yet every one of these proposals have failed. We hope they (agencies) will put resources into it so we don't have another site that has to be cleaned up under Superfund" rules, he said.

"We hope they figure out how to manage a mine without doing that, but so far, that hasn't happened," he said. "We just want to see them come up with a plan that actually works so we're not just creating another Superfund site."