Mesabi Metallics proposed air permit
Mesabi Metallics Co. LLC (Mesabi Metallics) is currently constructing a taconite mine and taconite pellet production facility on the site of the former Butler Taconite Mining Company facility near Nashwauk, Minn., with plans to also construct production facilities for integrated direct reduced iron (DRI) and steel. The Minnesota Pollution Control Agency (MPCA) first issued an air permit for the facility to then-owner/operator Minnesota Steel Industries in 2007. The MPCA issued a major amendment to the air permit in 2012 to then-owner/operator Essar Steel Minnesota.
An air permit is a legal document that describes how a facility must operate in order to meet federal and state air quality requirements. The type and quantity of pollutants emitted determines what type of permit is needed and what regulations apply. When reviewing the application materials, the MPCA determines how each piece of equipment must operate, often setting maximum production rates, emission limits, monitoring, and recordkeeping requirements. The MPCA drafts an air permit detailing these requirements and a technical support document (TSD) which contains the justification for the permit requirements.
The draft air permit covers operations at the Mesabi Metallics facility that emit air pollution, which includes production of taconite pellet, direct reduced iron (DRI), and steel. The main sources of emissions at the facility are: dust from mining, material crushing and handling sources, combustion emissions from the pellet furnace, direct reduced iron (DRI) module and electric furnace, and dust from the tailings basin.
The draft permit approves modifications to the pellet plant's equipment to update and refine its design and operation. It also approves Best Available Control Technology and tightens the emission limits for these modified emission units. The modifications do not include any change — increase or decrease — in the amount of pellets that Mesabi Metallics is allowed to produce annually. The draft permit also requires the company to:
- Re-evaluate the design and Best Available Control Technology of the DRI plant and steel plant before construction commences for each plant.
- Comply with the approved mercury reduction plan, which includes a 72-percent reduction in the uncontrolled mercury emissions from the pellet furnace.
- Conduct a moisture content study to verify control efficiency assumptions for unpaved roads.
- Conduct performance tests to demonstrate compliance with emission limits.
Public comment closed on September 14, 2020. The MPCA will review any comments and, if necessary, make changes to the draft permit. The proposed permit will be sent to the US Environmental Protection Agency (EPA) for a 45-day review period. At the conclusion of the 45-day EPA review, MPCA will review the administrative record and decide whether to issue the permit. A permit can only be issued if the facility is able to meet all applicable requirements. Most of the time, and in the case of Mesabi Metallics, an air permit must be issued before a facility can implement the proposed modifications. The permit is issued for a five-year term, after which it can be renewed for another five years.
Public notice documents
Other supporting documents
- Fugitive Dust Control Plan (Permit Appendix S)
- Ambient Air Boundary Control Plan (TSD Attachment 10)
- Mercury Reduction Plan (TSD Attachment 15)
- PM10/PM2.5 modeling report (Major amendment application supplement Appendix D)
- SO2 modeling protocol (Part 70 reissuance application supplement Appendix F)
For more information
Ben Wenkel, MPCA air permit engineer: 651-757-2603
For questions related to the Department of Natural Resource's mineral leasing or the permit to mine and mineland reclamation, please refer to their Lands and Mineral webpage.