Monsanto’s P4 Production, LLC, which operates an elemental phosphorus plant in Soda Springs, Idaho, has requested in a 313-page application that the Idaho Department of Environmental Quality (IDEQ) grant it an air quality permit to construct the proposed Blackfoot Bridge phosphate ore mine (GM Aug. 17, p. 1) about 10 miles northeast of the town in Caribou County.
A 30-day public comment period on the project will be provided if a written request is submitted to IDEQ by 5 p.m. MST, Friday, Dec. 4. Questions also may be directed to Faye Weber, Air Quality Division, IDEQ State Office, 1410 N. Hilton, Boise, ID 83706. She can be reached by telephone at (208) 373-0440, or via email at faye.weber@deq.idaho.gov.
If the permit is granted, construction would begin in 2010. Ore from the new mine would be expected to last through 2026. The Blackfoot Bridge Mine would consist of three open pits when it tentatively opens in 2011.
The phosphate ore from the new mine would replace an annual one million tons of ore from the South Rasmussen Ridge Mine, which is expected to be exhausted by 2013. That mine feeds Monsanto’s chemical processing plant, where ingredients for its popular Roundup weed-killing chemical are produced.
Total fugitive particulate emissions from the new mine are projected to peak at 121 tons per year in 2025. About 740 acres of mostly private land would be disturbed by the new mine operations, with only about 10 percent, or roughly 74 acres, on Bureau of Land Management land. About 80 of Monsanto’s 750 workers in the region would be employed at the mine.
P4 proposes to haul the ore to a hopper area and process it through screens and a crusher. The ore would then be conveyed to a truck loadout or “tipple” for hauling to the plant. Dust conditions there would be minimized by the inherent moisture content of the ore, which the application states is about 12 percent.
The Blackfoot Bridge Mine will be mined in phases, with mining and reclamation activities continuing for 17 years. This would require vegetation removal, topsoil stripping, overburden removal, ore processing, and reclamation activities over the mine’s life.
After vegetation and topsoil are removed, overburden would be drilled in a typical trucks-and-shovels operation. Once the overburden is removed, phosphate ore would be segregated and recovered from the north, middle, and south pits. Blasting would be done for the overburden and ore when needed. The ore would be loaded by track-mounted excavators and hauled via off-highway mining trucks to the feed-hopper area.