Boise-The Idaho Department of Environmental Quality has issued a revised construction permit to Agrium Inc.’s Nu-West Conda Phosphate Operations for its gypsum stacks seven miles north of Soda Springs, in Southeast Idaho’s Caribou County. The permit revises requirements for construction of the new West Gypsum Stack II or a phosphogypsum settling pond, clarifying pond surface size requirements, emissions limits, and monitoring requirements for the plant’s gypsum stacks. Mike Simon, an IDEQ official in its air quality division, informed Plant Manager Eric Vettergren of the decision in a Feb. 20 letter. The revised permit is based on Nu-West’s Dec. 24 application to replace a permit issued in December 2007. “This permit does not release Nu-West Industries Inc. from compliance with all other applicable federal, state or local laws, regulations, permits or ordinances,” Simon wrote, noting it also does not contravene any existing Tier I operating permit conditions. Construction and operation notification also must be provided, he said. The permit will expire if construction has not begun within two years of its issue date, or if construction is suspended for one year. When the new gypsum stack is completed, the combined fluoride emissions from the three 125-acre gypsum stacks shall not exceed 200 pounds per day or 14.6 tons per any consecutive rolling 12-month period. Before it is finished, combined fluoride emissions from the two existing gypsum stacks shall not exceed 200 pounds per day or 36.5 tons per any consecutive rolling 12-month period. The new gypsum stack shall include placing at least two feet of compacted phosphogypsum atop the composite liner membrane and compacted clay to ensure adequate liner integrity. At that point process water will be introduced, and when fully displaced by gypsum slurry in both cells, the construction process shall be deemed complete.
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