Blackfoot Bridge Mine Final Environmental Impact Statement

To open the Blackfoot Bridge mine, the Bureau of Land Management (BLM), who manages the phosphate ore leases, must prepare an environmental impact statement (EIS).  BLM released a draft EIS in August 2009 with a public comment period ending in early November 2009.  Of the approximately 6,800 comments submitted, a noteworthy 5:1 ratio expressed support for the new mine.   And, over 98% of the comments emanating from Idaho were supportive of the Blackfoot Bridge mine.

After thoroughly reviewing and addressing all of the comments on the draft EIS, the BLM prepared a Final EIS.  The Final EIS provides responses to everyone’s comments and highlights the many design improvements that address them.  These improvements include:

  • Use of the advanced Geo-synthetic Clay Liner Laminate is expanded.  This expansion and other refinements further encapsulate selenium-containing overburden or waste rock, minimizing the risk of water reaching the selenium-bearing material from the sides.
  • An already unprecedented water management system is further enhanced.  Water containing elevated levels of selenium will be captured on site 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 even water from a collection system under the overburden piles, will be captured and tested, with any water exceeding standards retained on site.  The Blackfoot Bridge mine water management system will be the most sophisticated and flexible monitoring ever proposed for an Idaho phosphate mine.
  • Monitoring is enhanced to address concerns that the cover may deteriorate over time, and potentially allow water to enter the overburden.  Long-term monitoring is provided to ensure the cover systems remain in functional condition for the designed hundreds of years.  Under this design specification, long before the liner might deteriorate a dense mat of vegetation will have covered the site, creating a “moisture storing” layer that further isolates the waste rock in much the same manner as occurred naturally before mining.
  • Committed to preserving an undeveloped 120-acre property in the Soda Springs vicinity that provides critical mule deer winter habitat.

Monsanto has reached out, listened and responded to a broad range of stakeholders, including state and regional conservation organizations, U.S. Environmental Protection Agency (EPA), and Idaho Department of Environmental Quality (IDEQ).

The Notice of Availability of the Final EIS was published in the Federal Register on March 11, 2011.  A Record of Decision approving the new mine can be issued no sooner than 30 days after the Final EIS is made available.