The U.S. Bureau of Land Management on March 11 published in the Federal Register its final Environmental Impact Statement (EIS) regarding Monsanto’s proposed controversial Blackfoot Bridge Mine in Southeast Idaho’s Caribou County.
The BLM’s final EIS calls for expanding a $25 million liner, enhancing a water management system, improving monitors, and committing to a 120-acre mule deer winter habitat in the Soda Springs vicinity. Monsanto added $10 million in design improvements for the final EIS. A Record of Decision approving the new open pit mine can be issued no sooner than 30 days after the EIS is published and public comments can be made.
Monsanto hopes to start mining operations at the new site this summer to provide phosphate for its 60-year-old, three-furnace Soda Springs elemental phosphorus plant, where Roundup herbicide is manufactured.
The mine would be 10 miles northeast of Soda Springs and about 600 feet from the Blackfoot River, which has been listed under the Clean Water Act as selenium-impaired. It is one of three mines under consideration in the Blackfoot River watershed, including Agrium’s Rasmussen Valley Mine and the J.R. Simplot Co.’s Dairy Syncline Mine.
The Monsanto mine would disturb about 740 acres and be 10 percent on BLM land and 90 percent on private land. It is estimated that its source of phosphate ore could keep the Soda Springs plant supplied for more than 15 years. Groundwater monitoring wells would surround it.
About 6,800 comments were submitted in response to the draft EIS released in August 2009, with most expressing support for the project. Private citizens, state and regional conservation organizations, the U.S. Environmental Protection Agency, and Idaho Department of Environmental Quality officials have provided input.
In the final EIS, the BLM said use of an advanced geo-synthetic clay liner laminate needed to be expanded to contain selenium-containing overburden or waste rock and prevent water from contacting it. Selenium-tainted water will be captured onsite and not discharged unless it meets state and federal water quality standards.
Individual sources of water will be managed to ensure compliance with water quality standards and maximize the amount of clean water returned into the watershed. Surface water and water collected under overburden piles will be captured and tested. If the water exceeds standards, it will be retained on site.
A dense mat of vegetation will cover the site to create a “moisture storing” layer to further isolate the waste rock. Monsanto officials say the mine’s water management system will be the most sophisticated, flexible monitoring ever proposed for a phosphate mine.
Jeff Cundick, the BLM minerals branch chief in Pocatello who oversees phosphate projects on the Caribou-Targhee National Forest, said Monsanto managed to submit an acceptable plan when needed protective measures were included. Mining below the water table is no longer planned.
Monsanto’s first phosphate mine opened in 1952, and it has operated three subsequent mines. The company employs 770 people, 375 who work directly for P4 Production LLC, Monsanto’s wholly-owned subsidiary, and 395 who work for subcontractors engaged in mining, plant maintenance, security and other directly related jobs, making Monsanto’s operations the largest of Caribou County’s phosphate mining and processing operations.
Monsanto’s annual payroll and benefits paid in 2010 totaled nearly $29 million. Annual mineral royalties paid to federal and state governments amounted to $1.3 million.