MPCA issues PolyMet final air and water quality permits and 401 certification
On December 20, 2018, the MPCA made final regulatory decisions to issue the PolyMet air emission permit, water quality permit, and 401 certification. The decisions were reached after comprehensive regulatory and technical analysis, extensive public participation, and review by other state/federal agencies and independent third-party experts.
This notification is the MPCA’s final progress report on the status of the PolyMet air emission permit, water quality permit, and 401 certification.
MPCA water quality permits establish specific limits and requirements to protect Minnesota's surface and groundwater quality for a variety of uses, including drinking water, aquatic life and recreation. These are also known as NPDES/SDS permits (National Pollutant Discharge Elimination System/State Disposal System).
The MPCA typically follows the process below for processing individual water quality permit applications.
* includes coordination with EPA
The public comment period for the draft water quality permit for PolyMet’s NorthMet project closed on March 16, 2018. The MPCA reviewed all comments and information received and has finalized responses to comments. This process resulted in changes to the draft permit that the MPCA incorporated into the proposed permit. The proposed permit and supporting documents were sent to the Environmental Protection Agency (EPA) for 15-day review on December 4, 2018 as part of the regular federal oversight of the state permitting program. Following conclusion of the review period, MPCA issued the final water quality permit on December 20, 2018.
Previous supporting documents
Public notice draft permit, fact sheet, and fact sheet attachments
Public meeting fact sheets
PolyMet permit highlights (wq-wwprm1-51t) (Jan 2018)
NPDES/SDS permit and sulfate (wq-wwprm1-51u) (Jan 2018)
Reverse osmosis (wq-wwprm1-51v) (Jan 2018)
October 2017 updated NPDES/SDS permit application
NPDES/SDS Permit Application - Vol II: Mine Site (wq-wwprm1-50v) (pdf 145.3 mb) (Oct 2017)
The initial July 2016 permit application and November 2016 update:
Key references cited in application
Wastewater Treatment System: Design and Operation Report v2 (wq-wwprm1-51b) (108.9 mb) (Oct 2017)
Correspondence related to permit application
Construction Stormwater General NPDES/SDS Permit
When a project includes land-disturbing activities totaling an acre or more, a Construction Stormwater Permit must be obtained from the Minnesota Pollution Control Agency. Land-disturbing activities are common practices related to construction. Some examples include removing vegetation, like grass or trees, changing the topography by using a bulldozer to level a slope, digging holes to examine the characteristics of the soil at the project site, or installing monitoring wells. These routine activities must be regulated by this permit because they have the potential to allow stormwater—runoff caused by rain and snowmelt—to carry dirt and pollutants into our lakes, rivers and streams.
Virtually all types and sizes of construction projects involve the same types of land-disturbing activities. Whether the project is building an apartment building, a new road or bridge, or digging holes to examine soil characteristics, similar actions involving land disturbance take place. All of these actions increase the potential for soil to runoff from the site and stormwater management practices can be used to reduce that potential. These practices are required by the Construction Stormwater General permit. Because the land disturbing activities on these various types of construction projects are similar, the appropriate regulatory mechanism is a general permit. General permits are used by the MPCA when a category of permittees has activities, operations, and discharges that are substantially similar. The Construction Stormwater General Permit has requirements that address all types of land-disturbing construction activity. Because the activities regulated by the permit are similar, land disturbing construction activities, the permit does not need to be modified for each project. Each permittee covered by the general permit must develop a Stormwater Pollution Prevention Plan (SWPPP), specific to the project, which details how the requirements of the permit will be met. The SWPPP takes into account the specific characteristics of the project and identifies the practices that will be implemented at the project to meet the requirements of the general permit. The SWPPP becomes an enforceable part of the permit.
The current Construction Stormwater General Permit was issued and became effective in August 2013. Prior to its issuance the permit went through a public-notice and comment process. When an applicant seeks coverage under this permit, there is no additional public comment period. Since the permit became effective, nearly 7,000 projects have been covered by this permit. When an applicant has submitted a complete and accurate application in accordance with the requirements of the general permit, they can be authorized to discharge stormwater associated with construction activity under the general permit.
On February 7, 2017, PolyMet submitted an application for a Construction Stormwater General Permit for geotechnical investigations at the NorthMet Project plant site and tailings basin. Geotechnical investigations are very common prior to construction of commercial buildings, apartments, road projects; examples include the Vikings stadium, the Saint Croix River Bridge and the Highway 53 project near Virginia. Since these activities disturb more than one acre of land, a Construction Stormwater General Permit is required before commencing the activity.
The purpose of PolyMet’s geotechnical work is to investigate and characterize geological conditions at the site prior to construction and mining operations. This includes such activities as borings and test pits to determine soil characteristics and depth to bedrock and installation of monitoring wells.
Coverage under the February 7, 2017, permit application was effective on March 9, 2017. Coverage under this application only authorizes activities related to geotechnical work; it does not authorize construction or operation of the processing facility, mine pits, or other construction activities. MPCA approved PolyMet’s SWPPP, which is now an enforceable part of the permit.
On March 13, 2017 and November 7, 2017, PolyMet submitted applications for a Construction Stormwater General Permit for additional geotechnical work; specifically mine site geotechnical investigation work and monitoring well installation. As with the February 7, 2017 application, coverage under this application only authorizes activities related to geotechnical work; it does not authorize construction or operation of the processing facility, mine pits, or other construction activities. Coverage under these permit actions was effective on April 12, 2017 and December 7, 2017 respectively. MPCA approved PolyMet’s SWPPP for each of these actions, which are now enforceable parts of the permits.
Coverage information for both permits is available online in the Construction Stormwater Permit Search.
Future construction stormwater permits
The applications received on February 7, March 13, 2017, and November 7, 2017, for coverage under the Construction Stormwater General Permit are related to geotechnical investigation and monitoring well installation in a portion of the project area. Additional geotechnical investigation, as well as land-disturbing construction activity related to other aspects of the project, will require additional future applications for coverage under the Construction Stormwater General permit.