Variance for Mesabi Nugget Facility
Mesabi Nugget Delaware, LLC
Hoyt Lakes, MN
(St. Louis County)
EPA finds Minnesota’s request for a variance from state water quality standards for Mesabi Nugget facility compliant with Clean Water Act
After a review of Minnesota’s request for a variance from state water quality standards for Mesabi’s iron ore processing demonstration plant near Hoyt Lakes, EPA has determined that the variance is consistent with federal regulations and the Clean Water Act. In October 2012, the Minnesota Pollution Control Agency requested that EPA review the variance. On Dec. 27, 2012, EPA approved Minnesota’s variance for the Mesabi facility, which produces iron nuggets from iron ore concentrate.
MPCA cited the following considerations in support of the Agency’s decision to propose a variance from four state water quality standards:
- Mesabi cannot fully comply with water quality standards until air pollution controls are operational.
- The type of air pollution control system capable of achieving compliance is uncertain because this is a first-of-its-kind demonstration plant.
- The air pollution control system will determine the ultimate design of the required wastewater treatment system.
- Pollutants from the mine pit would be discharged whether or not the facility is in operation.
The variance affects the hardness criterion for Minnesota’s Class 3C industrial water supply use and bicarbonate, total dissolved salts and specific conductance criteria for the Class 4A agricultural irrigation use for Second Creek, which is a tributary to the Partridge River in the St. Louis River Watershed complex. Minnesota’s variance also requires Mesabi to complete a number of studies on wastewater discharge. Mesabi must comply with water quality standards as soon as possible, but no later than Aug. 1, 2021. More details on the variance are available in the Agency’s decision document.
Mesabi is not allowed to discharge wastewater during the growing season for wild rice. Mesabi did not seek a variance from Minnesota’s water quality criterion for 10 mg/L waters used to produce wild rice.
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- EPA's approval letter (PDF) (2 pp, 487K) Dec. 27, 2012
- EPA Review of the Minnesota Pollution Control Agency Request for Approval of a Variance from Water Quality Standards (PDF) (22 pp, 780K) Dec. 27, 2012
- Letter to Bois Forte Band of Chippewa Indians Tribal Council (PDF) (4 pp, 481K) Dec. 27, 2012
- Letter to Fond du Lac Band of Lake Superior Chippewa Indians Tribal Council (PDF) (4 pp, 495K) Dec. 27, 2012
- Letter to Grand Portage Band of Chippewa Indians Tribal Council (PDF) (4 pp, 469K) Dec. 27, 2012
- MPCA's incoming request for EPA's review of the variance (PDF) (1 pg, 237K) Oct. 26, 2012