BARR – NPDES SDS Permit Application Volume VII – Transportation and Utility Corridors (TPD1607088)

NPDES/SDS Permit Application Volume VII – Transportation and Utility Corridors July 2016 Contents Application Forms ………………………………………………………………………………………………………………………………………………………….. 1

Permit Application Checklist for Industrial Wastewater ……………………………………………………………………………………… 1
Individual Industrial Stormwater Multi-Sector NPDES/SDS Permit Application ……………………………………………. 4
Industrial Chemical Additives Attachment ……………………………………………………………………………………………………………. 7
1.0 Introduction ……………………………………………………………………………………………………………………………………………………… 9
2.0 Transportation and Utility Corridors Water Management and Infrastructure ……………………………………13
2.1 Existing Conditions …………………………………………………………………………………………………………………………………….13
2.2 Stormwater Management and Infrastructure ……………………………………………………………………………………….13
2.2.1 Significant Materials ……………………………………………………………………………………………………………………………..14
2.2.2 Stormwater Management Systems ……………………………………………………………………………………………………15
2.2.2.1 Stormwater Management along the Railroad Corridor ………………………………………………………..16
2.2.2.2 Stormwater Management along Dunka Road and Treated Water Pipeline ……………………..16
2.3 Adaptive Management ……………………………………………………………………………………………………………………………..16
2.4 Chemical Additives …………………………………………………………………………………………………………………………………….17
2.5 Reclamation and Long-Term Closure …………………………………………………………………………………………………….17
3.0 Transportation and Utility Corridors Monitoring ……………………………………………………………………………………..19
3.1 Existing Surface Water Baseline Monitoring …………………………………………………………………………………………19
3.2 Proposed Monitoring Plan ……………………………………………………………………………………………………………………….21
4.0 References ……………………………………………………………………………………………………………………………………………………….22

List of Tables Table 1-1 Transportation and Utility Corridors Summary …………………………………………………………………………… 9
Table 1-2 Project Water Definitions ……………………………………………………………………………………………………………… 11
Table 1-3 Volume VII of PolyMet’s NPDES/SDS Permit Application Cross-Reference ……………………….. 12
Table 2-1 Significant Materials along the Transportation and Utility Corridors that have the Potential to Contact Stormwater and Associated Management Methods …………………………. 15
Table 3-1 Summary of Baseline Surface Water Monitoring Stations (2004 through 2015) ………………. 19
Table 3-2 Baseline Exceedances of Applicable Surface Water Standards at Monitoring
Stations WL-1 and LN-1 (2011 through 2015) …………………………………………………………………………. 20
Table 3-3 Baseline Exceedances of Applicable Surface Water Standards at Monitoring
Stations PM-5 and PM-6 (2004 through 2015) ………………………………………………………………………… 21
List of Large Tables Large Table 1 Transportation and Utility Corridors Chemical Additives
Large Table 2 Transportation and Utility Corridors Baseline Surface Water Quality Monitoring Summary
List of Large Figures Large Figure 1 Site Location
Large Figure 2 Transportation and Utility Corridors Existing Conditions
Large Figure 3 Transportation and Utility Corridors Layout
List of Appendices Appendix A Permit Application Support Drawings
Appendix B Chemical Additives Safety Data Sheets
Appendix C Industrial SWPPP Outline (Draft)

List of Acronyms and Abbreviations
Acronyms or Abbreviation Description
BMP Best Management Practice
NPDES National Pollutant Discharge Elimination System
SDS State Disposal System
SWPPP Stormwater Pollution Prevention Plan
TWP Treated Water Pipeline
WWTF Waste Water Treatment Facility

Permit Apllication Checklist for Industrial Wastewater

Individual Industrial Stormwater Multi-Sector NPDES/SDS Permit Application

Industrial Chemical Additives Attachment

1.0 Introduction
This volume, Volume VII of the National Pollutant Discharge Elimination System (NPDES) / State Disposal
System (SDS) Permit Application for Poly Met Mining, Inc.’s (PolyMet) NorthMet Project (Project), focuses
on the Transportation and Utility Corridors. Refer to Section 2.0 of Volume I for discussion of the
permitting approach for this permit application as it applies to the Transportation and Utility Corridors.
Table 1-1 provides a high-level overview of the Transportation and Utility Corridors.
Table 1-1 Transportation and Utility Corridors Summary
Transportation and Utility Corridors Summary
Purpose
To provide connections between the Project Mine Site and Plant Site for ore transport,
vehicle traffic, treated mine water conveyance, brine transport from the Waste Water
Treatment Plant (WWTP) to the Waste Water Treatment Facility (WWTF), and power
transmission, and to manage associated stormwater runoff in a manner that results in
compliance with applicable stormwater requirements and applicable water quality
standards at appropriate compliance points.
Location Between the Project Mine Site and Plant Site (Large Figure 1)
Facility description
Two Transportation and Utility Corridors that are each approximately 7 to 8 miles in
length:
· The railroad corridor includes a private railroad that will transport ore from the
Mine Site to the Plant Site via the existing Cliffs Erie railroad and a new Rail
Connection Track.
· The Dunka Road and utility corridor includes an upgraded segment of the
existing private Dunka Road that will provide vehicle access between the Mine
Site and Plant Site; and a new Treated Water Pipeline (TWP) to convey water
between the Mine Site and Plant Site. This corridor also includes a 13.8 kilovolt
distribution line to the Mine Site feed by a new Minnesota Power electrical
substation.
Treated mine water
management and
discharge
No discharge. Treated mine water will be transported in the TWP along the Dunka Road
and utility corridor.
Stormwater
management and
discharge
Stormwater will be controlled by and discharged through a series of ditches and culverts.
Stormwater will be managed in a manner that reduces potential impacts to the Project,
protects the environment, and maintains existing flow patterns to the extent practicable.
Estimated commission
Infrastructure is existing or will be upgraded or constructed during an estimated 18-24
month pre-operation construction phase prior to Mine Year 1(1)
(1) Mine Year 1 is the year when blasting commences to access ore at the Mine Site.

This volume is organized in three sections:
Section 1.0 Provides an overview of the Transportation and Utility Corridors and provides the
water definitions specific to the volume.
Section 2.0 Describes water management and infrastructure along the Transportation and Utility
Corridors, including existing conditions, stormwater management and infrastructure,
adaptive management, chemical additives, and reclamation and long-term closure.
Section 3.0 Summarizes the proposed monitoring plan for the Transportation and Utility
Corridors.
In accordance with Minnesota Rules, part 6132.0200, the Transportation and Utility Corridors have been
designed “to control possible adverse environmental effects of nonferrous metallic mineral mining, to
preserve natural resources, and to encourage planning of future land utilization.” The design of the
Transportation and Utility Corridors includes systems for managing water in a manner that results in
compliance with applicable water quality standards at appropriate compliance points (Section 1.1 of
Reference (1)). The water management systems have been designed to achieve compliance based on
modeling of expected water quantity and quality; additionally, plans have been developed for adaptive
management (Section 6.5 of Reference (1)) and contingency mitigation (Section 6.6 of Reference (1)) as
deemed necessary to maintain compliance (refer to Section 2.3 of this volume for further discussion).
Water management includes management of stormwater and conveyance of treated mine water through
the Treated Water Pipeline (TWP) from the Mine Site to the Plant Site. The TWP is included on Large
Figure 4 in Volume I, which depicts the general flow of water throughout the Project.
Table 1-2 provides definitions for the terms treated mine water, industrial stormwater, construction
stormwater, and non-contact stormwater, as well as notes regarding the definitions’ application to specific
facets along the Transportation and Utility Corridors.
As part of this application, PolyMet requests authorization to discharge stormwater associated with
industrial activities along the Transportation and Utility Corridors under the Minnesota NPDES/SDS
Industrial Stormwater General Permit (Permit No. MNR050000). Refer to Section 2.2 of this volume for
further details on the management of stormwater during operations.
A separate application is being submitted requesting authorization to discharge stormwater associated
with pre-operation construction activities along the Transportation and Utility Corridors under the
Minnesota NPDES/SDS Construction Stormwater General Permit (Permit No. MNR100001).

Table 1-2 Project Water Definitions
Project-Specific
Term Project-Wide Definition(1)
Transportation and Utility Corridors
Specifics
Treated Mine
Water
Water routed from the Mine Site to the
Tailings Basin via the Treated Water Pipeline
(TWP).
(no additions to Project-Wide Definition)
Industrial
Stormwater
Stormwater associated with industrial
activities(2).
Includes precipitation and runoff from Dunka
Road and the railroad between the Mine Site
and the Plant Site.
Construction
Stormwater
Stormwater associated with construction
activities(3).
(no additions to Project-Wide Definition)
Non-Contact
Stormwater
Precipitation and runoff that contacts natural,
stabilized, or reclaimed surfaces and has not
been exposed to mining activities,
construction activities(3), or industrial
activities(2).
(no additions to Project-Wide Definition)
(1) If two types of waters mix, the mixture is handled as the more actively managed type of water (e.g., a mixture of noncontact
stormwater and industrial stormwater is managed as industrial stormwater). Management of water mixtures will be
governed by regulatory requirements.
(2) As defined in Minnesota Rules, part 7090.0080, subpart 6
(3) As defined in Minnesota Rules, part 7090.0080, subpart 4
During environmental review, PolyMet developed numerous Management Plans to provide details of the
design, construction, operation, reclamation, and long-term closure of the Project. The Management Plans
rely on and incorporate the results of Data Packages, which are compilations of technical data and related
supporting information.
Information from the above-referenced documents, as well as from permit applications and issued
permits, will be incorporated into an operations plan for use during operations, reclamation, and longterm
closure phases of the Project. Refer to Section 1.10 of Volume I for a description of the Project
phases.
To help the reviewer navigate the supporting material for Volume VII of this NPDES/SDS Permit
Application, Table 1-3 cross references key Transportation and Utility Corridors-related topics, PolyMet
Management Plans and Data Packages, sections of this narrative, and permit application requirements.

2.0 Transportation and Utility Corridors Water
Management and Infrastructure
This section focuses on water management associated with the Transportation and Utility Corridors
during operations, specifically during the period covered by this permit application (approximately Mine
Years 1 through 5). The following sub-sections describe:
· the existing site conditions (Section 2.1)
· the stormwater management systems (Section 2.2)
· the adaptive management approach that can be used to modify Transportation and Utility
Corridors water management systems in response to site-specific conditions encountered during
operations (Section 2.3)
· chemical additives proposed for use along the Transportation and Utility Corridors (Section 2.4)
· an overview of plans for reclamation and long-term closure (Section 2.5)
Permit application support drawings for water management systems along the Transportation and Utility
Corridors are included in Appendix A.
2.1 Existing Conditions
The Transportation and Utility Corridors connect the Mine Site and the Plant Site. These corridors include
the existing Dunka Road corridor and existing railroad corridor. PolyMet has acquired the necessary
easements and rights-of-way to use a seven-mile segment of Dunka Road, parts of which are owned by
Minnesota Power, PolyMet, and Cliffs Erie. PolyMet has also acquired ownership or the right to use
additional lands, trackage, and other railroad assets to secure the rail access between the Mine Site and
the Plant Site (Section 3.3 of Reference (2)). Portions of the Transportation and Utility Corridors are
located on land included in the proposed land exchange between PolyMet and the U.S. Forest Service.
The Transportation and Utility Corridors drain toward the Partridge River, a tributary of the Upper St. Louis
River. Specifically, the Transportation and Utility Corridors naturally drain to the south through culverts
under Dunka Road and the railroad to Wetlegs Creek, Longnose Creek, and Wyman Creek, all of which are
tributaries to the Partridge River. The subwatersheds and associated water bodies along the
Transportation and Utility Corridors are shown on Large Figure 2.
Refer to Section 3.1 of this volume for discussion of baseline surface water quality.
2.2 Stormwater Management and Infrastructure
This section describes the management of stormwater along the Transportation and Utility Corridors,
including best management practices (BMPs) and the design and operation of the infrastructure that will
be used to manage stormwater in accordance with applicable regulations.

Consistent with the overall Project approach (Table 1-2 of this volume), stormwater along the
Transportation and Utility Corridors is defined in three categories:
· construction stormwater, which consists of stormwater associated with construction activities
· industrial stormwater, which consists of stormwater associated with industrial activities
· non-contact stormwater, which consists of precipitation and runoff that contacts natural,
stabilized, or reclaimed surfaces and has not been exposed to mining activities, construction
activities, or industrial activities
Stormwater infrastructure will be constructed or upgraded from existing conditions as necessary prior to
commencement of Project operations. As discussed in Section 1.0 of this volume, a separate application is
being submitted requesting authorization to discharge stormwater associated with pre-operation
construction activities along the Transportation and Utility Corridors under the Construction Stormwater
General Permit. Therefore, stormwater management during construction is not discussed further in this
section. In order to meet the permanent stormwater management requirements of the Construction
Stormwater General Permit, additional stormwater features beyond those discussed herein may be
included in the Construction Stormwater Pollution Prevention Plan (SWPPP) and final engineering designs.
If additional stormwater features are deemed necessary, additional site-specific information (e.g., depth to
bedrock) will be required prior to final design. Such potential stormwater features have not yet been
incorporated into the attached Permit Application Support Drawings.
Also as discussed in Section 1.0 of this volume, as part of this application PolyMet requests authorization
to discharge stormwater associated with industrial activities along the Transportation and Utility Corridors
under the Industrial Stormwater General Permit. PolyMet will develop and implement an Industrial SWPPP
in accordance with Industrial Stormwater General Permit requirements, which will incorporate and expand
upon the discussions in this section. A draft outline of the Industrial SWPPP is included as Appendix C.
During operations along the Transportation and Utility Corridors, stormwater will be managed in a manner
that reduces potential impacts from the Project, protects the environment, and maintains existing flow
patterns to the extent practicable. As described in Section 2.2.2, stormwater along the Transportation and
Utility Corridors will be controlled by a series of ditches and culverts. Stormwater is expected to meet
water quality standards either without treatment or after being routed through on-site BMPs to remove
total suspended solids (TSS).
2.2.1 Significant Materials
Significant materials are defined by 40 CFR § 122.26(b)(12) as including, but not limited to: “raw materials;
fuels; materials such as solvents, detergents, and plastic pellets; finished materials such as metallic
products; raw materials used in food processing or production; hazardous substances designated under
Section 101(14) of the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA); any chemical the facility is required to report pursuant to Section 313 of the Emergency
Planning and Community Right-to-Know Act (EPCRA); fertilizers; pesticides; and waste products such as
ashes, slag, and sludge that have the potential to be released with stormwater discharges.”

Stormwater may come into contact with significant materials along the Transportation and Utility
Corridors and will be managed throughout the life of the Project using appropriate BMPs, including
engineered controls and spill prevention and response procedures, to reduce or eliminate contact or
exposure of pollutants to stormwater or remove pollutants from stormwater.
Table 2-1 describes significant materials along the Transportation and Utility Corridors that have the
potential to come into contact with stormwater, indicates whether the corresponding stormwater will be
managed as industrial stormwater (as defined in Table 1-2 of this volume) or in another manner, and
summarizes the associated management method(s). This information will also be included in the Industrial
SWPPP that will be developed for the Transportation and Utility Corridors.
Table 2-1 Significant Materials along the Transportation and Utility Corridors that have the
Potential to Contact Stormwater and Associated Management Methods
Material
Material description and
stormwater pollution
potential
Runoff will be
managed as: Management method(s)
Ore
Average sulfur content of
0.608%; has similar geochemical
properties as Category 4 Waste
Rock
industrial stormwater
Will be transported in rail cars which
will be refurbished to minimize
spillage.
Waste Water
Treatment
Facility (WWTF)
Sludge
Sludges resulting from chemical
precipitation processes within
the WWTF, including metal/iron
sludge, gypsum sludge, and
calcite sludge
any precipitation
contacting sludge
during transportation
will be disposed of
with sludge
Will be transported in a water-tight
trailer from the WWTF to the
Hydrometallurgical Residue Facility or
to an approved off-site disposal
facility.
Spills and Leaks
May include petroleum and
petroleum-based products from
vehicles that have the potential
to contaminate drainage
industrial stormwater
Non-structural best management
practices (BMPs) will be employed to
prevent spills and leaks. If spills and
leaks occur along the Transportation
and Utility Corridors, clean-up will be
managed in accordance with the
Project Spill Prevention, Control, and
Countermeasure (SPCC) Plan.
2.2.2 Stormwater Management Systems
The stormwater management systems were designed to support the features that will be constructed or
refurbished prior to Project operations. Upon completion of pre-operation construction activities along
the Transportation and Utility Corridors, the railroad, Rail Connection Track, Dunka Road, and TWP will be
completed, as shown on Large Figure 3 (Section 4.1.1 of Reference (2)). To maintain existing drainage
patterns to the extent practical, stormwater ditches and culverts along the railroad and Dunka Road
corridor will be retained and extended (Sections 2.2.2.1 and 2.2.2.2) and additional culverts will be
installed under the Railroad Connection Track (Section 2.2.2.1) and through the TWP embankment
(Section 2.2.2.2). Stormwater will discharge to Wetlegs Creek, Longnose Creek, and Wyman Creek in the
Partridge River watershed.

2.2.2.1 Stormwater Management along the Railroad Corridor
The 8-mile private railroad located between the Mine Site and Plant Site will consist of a refurbished
segment of the existing Cliffs Erie private railroad and a newly constructed Rail Connection Track. The Rail
Connection Track, approximately 5,750 feet in length, will connect the existing Cliffs Erie private railroad to
the existing NorthMet railroad at the Plant Site, which serves the Coarse Crusher Building (Section 2.1.3 of
Reference (3)).
Ditching along new sections of railroad bed will direct surface water and stormwater flow through culverts.
The Rail Connection Track will include culverts at two locations to facilitate drainage around the new track,
while maintaining existing drainage patterns to the extent practical. Stormwater from the Rail Connection
Track will discharge east to Wyman Creek.
2.2.2.2 Stormwater Management along Dunka Road and Treated Water Pipeline
An existing 7-mile segment of Dunka Road, located between the Mine Site and the Plant Site, will be
upgraded prior to commencement of Project operations. The upgraded Dunka Road will be designed to
accommodate the anticipated traffic and to meet the requirements of Mine Safety and Health
Administration Standard 56.9300, including a 40 feet wide driving surface, approximately six foot high
safety berms where needed, and passing bays to allow haul trucks traveling in opposite directions to pass
each other. Typical cross-sections for the upgraded Dunka Road are provided in the Mine Site and Dunka
Road Earthwork Permit Application Support Drawings in Appendix A.
The footprint of the upgraded Dunka Road will be similar to the existing footprint, with the exception of
the added passing bays. Stormwater features at the toe of the road and along the vegetated side slopes
will also be similar to existing features, except along the passing bays, where existing culverts will be
extended and embankments will be added to facilitate a widening of the road surface.
The TWP, approximately 40,000 feet in length, will generally run parallel to Dunka Road. The TWP will
transport treated mine water from the Mine Site to the Tailings Basin at the Plant Site. The TWP will be
contained within a berm, typically above existing ground level. Culverts underneath the TWP will maintain
existing drainage patterns. Further details regarding the design and operation of the TWP can be found in
Section 2.1.7 of Reference (1), and the Mechanical Infrastructure Permit Application Support Drawings are
included in Appendix A.
2.3 Adaptive Management
The Transportation and Utility Corridors water management systems have been designed to achieve
compliance based on modeling of expected water quantity and quality. As described in Section 1.9 of
Volume I, if water quality objectives are not met by these engineering controls, PolyMet will use an
adaptive management approach, as necessary, to improve performance. As part of the adaptive
management approach along the Transportation and Utility Corridors, studies will first be undertaken to
determine the root cause of the problem. Second, the design or operation of existing (or planned) Project
engineering controls will be modified to remedy the root cause. Third, if modifying the design or
operation of Project engineering controls is not sufficient, then contingency mitigation actions will be

taken. Fourth, outcomes will be monitored and may be evaluated with water modeling. This process is
meant to be iterative and will be repeated as necessary. The process for implementing adaptive
management along the Transportation and Utility Corridors is described in Section 6.5 of Reference (1)
and Section 2.1 of Reference (4).
Section 6.6 of Reference (1) presents feasible contingency mitigation actions available to address potential
water quality concerns in streams along the railroad corridor.
2.4 Chemical Additives
Chemical additives, specifically chemical dust suppressants, will be used to control fugitive dust emissions
along the Transportation and Utility Corridors and to prevent sedimentation and entrainment of dust in
stormwater and nearby water bodies. Chemical dust suppression will be used to bind the dust to the road
surface. Dust suppressants are typically applied approximately one time per year and watered as
necessary to reactivate the binding agents in the dust suppressant chemicals.
In order to mitigate potential environmental transport of the applied suppressants, BMPs will be
implemented when calculating usage rates and applying products. The U.S. Environmental Protection
Agency (Reference (7)) and Minnesota Pollution Control Agency (Reference (8)) provide guidance on the
BMPs associated with the usage of chemical dust suppressants. Adherence to usage BMPs will limit the
off-site transport of chemical additives. For example, information from vendors and/or field trials and
usage will allow for optimization of application rates, application frequency, and the water dilution to
product ratio, so that only the minimum amount of treatment needed to achieve successful dust
suppression will be applied to surfaces. Optimizing treatment will result in minimization of pooling, runoff,
and costs. Chemical dust suppressants will not be applied immediately adjacent to water bodies or when
it is raining or when rain is imminent. Other BMPs for application and usage of chemical dust
suppressants will be used when applicable.
Additional information regarding each proposed dust suppressant is included in Large Table 1.
Additionally, Safety Data Sheets and product information labels for each proposed dust suppressant are
included in Appendix B. Based on project economics and the availability of specific products, dust
suppressants may be acquired from multiple manufacturers provided that the chemical additive is
commensurate with the use proposed within this application. Several different dust suppressant products
are listed, and the decision on which product to use will be determined and reevaluated throughout the
Project.
2.5 Reclamation and Long-Term Closure
As currently planned, reclamation activities along the Transportation and Utility Corridors will begin after mining ceases in Mine Year 20. These activities will include reclamation of stormwater features associated with the railroad corridor and the TWP portion of the Dunka Road and utility corridor.
Portions of the railroad corridor existed prior to the Project and thus may remain after reclamation of other Project features. Other parts of the railroad corridor, including the Railroad Connection Track, will be removed and recycled or disposed, and the railbed will be reclaimed or evaluated for an approved subsequent use. In areas where locomotives may have remained stationary for extended periods, an inspection will be performed of potential petroleum product releases, and if necessary, remediation measures will be completed. PolyMet will also conduct a survey to inspect for potential ore spillage along the railroad corridor between the Rail Transfer Hopper and the Plant Site. If spillage is found that could cause water quality degradation, clean-up measures will be completed (Section 4.5 of Reference (5)).

Dunka Road was not constructed as part of the Project and thus may remain after reclamation of other Project features. The TWP will continue to be used in reclamation for flooding of the West Pit; once no longer needed, the TWP will be abandoned in-place.

3.0 Transportation and Utility Corridors Monitoring
Monitoring of baseline water quality and quantity has been ongoing in the vicinity of the Transportation
and Utility Corridors. As the Project commences, monitoring will continue at specific locations for a variety
of purposes, including compliance with this permit. Baseline monitoring data from monitoring stations
presented in the NorthMet Mining Project and Land Exchange Final Environmental Impact Statement
(FEIS) (Reference (9)) (which includes stations proposed in the NPDES/SDS monitoring plan) is described
in Section 3.1; Section 3.2 provides information on the proposed monitoring plan.
3.1 Existing Surface Water Baseline Monitoring
The Transportation and Utility Corridors are located in the Partridge River watershed, approximately 16
river miles upstream of Colby Lake. Portions of the Transportation and Utility Corridors are located within
the Partridge River watershed and the following subwatersheds: Upper Partridge subwatershed, Wetlegs
Creek subwatershed, Longnose Creek subwatershed, Wyman Creek subwatershed, and Second Creek
subwatershed.
These tributaries of the Partridge River, which have potential to be impacted by the Transportation and
Utility Corridors, have been monitored for water quality and quantity since 2004, as summarized in
Table 3-1; existing monitoring stations are shown on Large Figure 2.
Table 3-1 Summary of Baseline Surface Water Monitoring Stations (2004 through 2015)
Current
Monitoring
Station ID Water Body(1)
Water Quality
Monitoring Years
Average
Instantaneous
Flow (cfs)
Number of
Flow
Measurements
Flow
Measurement
Monitoring Years
WL-1 Wetlegs Creek 2011-2015 N/A N/A N/A
LN-1 Longnose Creek 2011-2015 N/A N/A N/A
PM-5
Wyman Creek
2004; 2011-2015 0.8 4 2004
PM-6 2004 0.1(2) 3 2004
(1) Station PM-4 monitors the Partridge River downstream of the Transportation and Utility Corridors. Refer to Table 3-1 in
Volume II for information on PM-4.
(2) Flow was observed on 1 of 3 occasions evaluated.
Refer to Large Table 2 for a summary of the baseline surface water quality monitoring results and
Section 4.4.4 of Reference (6) and Reference (10) for detailed baseline surface water quality results. The
frequency and extent (i.e., number of constituents) of monitoring varied by location. Monitoring
conducted in 2004 generally included a wider list of constituents to characterize the baseline conditions
within the watershed. Monitoring in 2011 generally focused on a smaller list of constituents to resolve
specific issues with the data. More comprehensive baseline monitoring was resumed in 2012 with a wider
list of constituents (Section 1.3.1 of Reference (1)).

Under Minnesota Rules, part 7050.0430, Wetlegs Creek and Longnose Creek are unlisted waters with the
default classification of Class 2B, 3C, 4A, 5, and 6. Wyman Creek is a listed water under Minnesota Rules,
part 7050.0470 with the classification of Class 1B, 2A, 3C, 4A, 4B, 5, and 6. Baseline conditions exceed
applicable surface water quality standards for several parameters, as summarized in Table 3-2 (for Class
2B, 3C, 4A, 5, and 6 waters) and Table 3-3 (for Class 1B, 2A, 3C, 4A, 4B, 5, and 6 waters). The baseline water
quality of the surface water bodies along the Transportation and Utility Corridors represents a mixture of
natural background levels and the possible influence of past industrial operations.
Table 3-2 Baseline Exceedances of Applicable Surface Water Standards at Monitoring
Stations WL-1 and LN-1 (2011 through 2015)
Parameter
Number of
Samples
Water Quality Standard and Number of Exceedances(1)
2B(2) 3C 4A 4B 5
Aluminum (dissolved) 90 125 μg/L 12 N/A – N/A – N/A – N/A –
Aluminum (total) 90 125 μg/L 22 N/A – N/A – N/A – N/A –
Cobalt (dissolved) 62 5 μg/L 7 N/A – N/A – N/A – N/A –
Cobalt (total) 90 5 μg/L 9 N/A – N/A – N/A – N/A –
Copper (dissolved) 62 2.00-8.52 μg/L(2,3) 9 N/A – N/A – N/A – N/A –
Copper (total) 90 2.04-11.21 μg/L(2,4) 16 N/A – N/A – N/A – N/A –
Lead (total) 84 0.33-4.18 μg/L(5) 1 N/A – N/A – N/A – N/A –
Mercury 40 0.0013 μg/L(2) 38 N/A – N/A – N/A – N/A –
pH (SU) 90 6.5-9.0 17
6.0-
9.0
0
6.0-
8.5
0
6.0-
9.0
0
6.0-
9.0
0
Sulfate 92 N/A – N/A – N/A(6) – N/A – N/A –
Zinc (total) 88 26.56-143.77 μg/L(2,7) 1 N/A – N/A – N/A – N/A –
(1) These columns show applicable water quality standards for the stations and the number of exceedances for each
standard.
(2) Minnesota Rules, chapter 7052 establishes additional surface water quality standards for Class 2 water bodies within the
Lake Superior Basin. The Lake Superior Basin water quality standards in this table include copper (dissolved), copper
(total), mercury, and zinc (total).
(3) Copper (dissolved) is a hardness-dependent water quality standard. The copper (dissolved) standard was calculated on an
event-by-event basis for each monitoring event using the conversion factor from copper (total). The range listed here is
the minimum and maximum standard calculated for WL-1 and LN-1.
(4) Copper (total) is a hardness-dependent water quality standard. The copper (total) standard was calculated on an eventby-
event basis for each monitoring event. The range listed here is the minimum and maximum standard calculated for
WL-1 and LN-1.
(5) Lead (total) is a hardness-dependent water quality standard. The lead (total) standard was calculated on an event-byevent
basis for each monitoring event. The range listed here is the minimum and maximum standard calculated for WL-1
and LN-1.
(6) The waterbodies corresponding with these monitoring stations are not listed wild rice waters; therefore the Class 4A
sulfate standard of 10 mg/L for waters “used for production of wild rice” is not applicable. Monitoring at these stations
during the specified time period has observed 2 instances where baseline sulfate concentrations were greater than 10
mg/L.
(7) Zinc (total) is a hardness-dependent water quality standard. The zinc (total) standard was calculated on an event-by-event
basis for each monitoring event. The range listed here is the minimum and maximum standard calculated for WL-1 and
LN-1.

Table 3-3 Baseline Exceedances of Applicable Surface Water Standards at Monitoring
Stations PM-5 and PM-6 (2004 through 2015)
Parameter
Number
of
Samples
Water Quality Standard and Number of Exceedances(1)
1B 2A(2) 3C 4A 4B 5
Aluminum
(total)
61 50 μg/L 9 87 μg/L 6 N/A – N/A – N/A – N/A –
Arsenic
(total)
61 10 μg/L 0 2 μg/L 6 N/A – N/A – N/A – N/A –
Cobalt
(total)
61 5 μg/L 1 2.8 μg/L 1 N/A – N/A – N/A – N/A –
Cyanide 8 0.2 mg/L 1 0.0052 mg/L 1 N/A – N/A – N/A – N/A –
Iron
(dissolved)
39 300 μg/L 27 N/A – N/A – N/A – N/A – N/A –
Iron (total) 61 300 μg/L 56 N/A – N/A – N/A – N/A – N/A –
Manganese
(dissolved)
29 50 μg/L 29 N/A – N/A – N/A – N/A – N/A –
Manganese
(total)
61 50 μg/L 61 N/A – N/A – N/A – N/A – N/A –
Mercury 41 2 μg/L 0 0.0013 μg/L(2) 10 N/A – N/A – N/A – N/A –
pH (SU) 61 6.5-8.5 2 6.5-8.5 2 6.0-9.0 0 6.0-8.5 0 6.0-9.0 0 6.0-9.0 0
Sulfate 61 250 μg/L 0 N/A – N/A – N/A(3) – N/A – N/A –
Total
Suspended
Solids (TSS)
26 N/A – 10 mg/L 4 N/A N/A – N/A – N/A –
Turbidity 51 5 NTU 14 N/A – N/A – N/A – N/A – N/A –
(1) These columns show applicable water quality standards for the stations and the number of exceedances for each standard.
(2) Minnesota Rules, chapter 7052 establishes additional surface water quality standards for Class 2 water bodies within the Lake
Superior Basin. The Lake Superior Basin water quality standards in this table include mercury.
(3) Wyman Creek is not a listed wild rice waters; therefore the Class 4A sulfate standard of 10 mg/L for waters “used for
production of wild rice” is not applicable. Monitoring at these stations during the specified time period has observed 59
instances where baseline sulfate concentrations were greater than 10 mg/L.
3.2 Proposed Monitoring Plan
Monitoring proposed for the Transportation and Utility Corridors is included in the integrated Mine Site
monitoring plan presented in Section 3.0 of Volume I. The proposed Mine Site monitoring plan includes
surface water monitoring stations and benchmark stormwater monitoring locations associated with the
Transportation and Utility Corridors; these proposed monitoring stations are shown on Large Figure 3.

4.0 References
1. Poly Met Mining Inc. NorthMet Project Water Management Plan – Mine Site (v5). July 2016.
2. —. NorthMet Project Project Description (v9). February 2015.
3. —. NorthMet Project Mine Plan (v5). July 2016.
4. —. NorthMet Project Adaptive Water Management Plan (v10). July 2016.
5. —. NorthMet Project Reclamation Plan (v7). July 2016.
6. —. NorthMet Project Water Modeling Data Package Volume 1 – Mine Site (v14). February 2015.
7. U.S. Environmental Protection Agency. Dust Control. Water: Best Management Practices. [Online] July
1, 2014. http://water.epa.gov/polwaste/npdes/swbmp/Dust-Control.cfm.
8. Minnesota Pollution Control Agency. Dust Control Treatments for Roads and Surfaces (aq1-15). April
2013.
9. Minnesota Department of Natural Resources, U.S. Army Corps of Engineers and U.S. Forest
Service. Final Environmental Impact Statement: NorthMet Mining Project and Land Exchange. November
2015.
10. Barr Engineering Co. 2014-2015 Surface water and groundwater quality data collected for the
NorthMet Project Technical Memorandum to Jennifer Saran, PolyMet Mining Inc. May 27, 2016.

Large Tables

Large Figures

Appendices

Appendix A
Permit Application Support Drawings
Mine Site and Dunka Road Earthwork
Mechanical Infrastructure

Mine Site and Dunka Road Earthwork Permit Application Support
Drawings

Errata Sheet
Poly Met Mining Inc. NorthMet Project
Permit Application Support Drawings: Mine Site and Dunka Road Earthwork
May 2016
The table below lists changes that were identified during completion of the Construction Stormwater
Pollution Prevention Plans (SWPPPs) and have not yet been incorporated in the attached permit
application support drawings within this set. These changes and additional details developed during final
design will be incorporated into the final design drawing set.
Drawing Sheet(s) Change
Global change to all sheets, as
needed
The terminology “mine drainage” as noted in these drawings
has been changed to “mine water”.
EW-003 Infiltration basins were added along Dunka Road to treat
impervious areas from Dunka Road passing bays.

 (11 images)

Mechanical Infrastructure Permit Application Support Drawings

Errata Sheet
Poly Met Mining Inc. NorthMet Project
Permit Application Support Drawings: Mechanical Infrastructure
May 2016
The table below lists changes that were identified during completion of the Construction Stormwater
Pollution Prevention Plans (SWPPPs) and have not yet been incorporated in the attached permit
application support drawings within this set. These changes and additional details developed during final
design will be incorporated into the final design drawing set.
Drawing Sheet(s) Change
Global change to all sheets, as
needed
The terminology “mine drainage” as noted in these drawings
has been changed to “mine water”.
MD-003 The grading for the access road from the Fueling and
Maintenance Facility to Pond MD-SOSP & Sump SOSP has
been revised as a result of additional engineering.
MD-001 To meet requirements, Sump 2 overflow pond and associated
piping was added to the SWPPP where the “construction
water pond” callout is located on MD-001.
TWP-009 The berm over the TWP was revised to match the contours of
the road where it crosses the proposed access roads near the
CPS.
MD-001 An access road has been added adjacent to a Mine Water
pipe for construction and maintenance purposes. This access
road follows the Mine Water pipe that connects the Category
1 Stockpile and Haul Road F (in a general north-south
orientation).
TWP-010 The option of rock as the top berm surface was eliminated to
minimize additional impervious surfaces. Remove “or 1” minus
rock” text on Sections 1, 2, 4 & 5.

(35 images)

Appendix B
Chemical Additives Safety Data Sheets

Appendix B Chemical Additives Safety Data Sheets
July 2016
Contents
Dust Suppressants Magnesium Chloride Aqueous Solution (Dustgard) ……………………………………………………………………………………..B-1
Aqueous Amorphous Polymer Solution (BT-468) ………………………………………………………………………………………….B-9
Roadsaver-C ………………………………………………………………………………………………………………………………………………………. B-17
Roadsaver …………………………………………………………………………………………………………………………………………………………… B-23
Durasoil ………………………………………………………………………………………………………………………………………………………………. B-29
Gorilla Snot ………………………………………………………………………………………………………………………………………………………… B-41
Soiltac …………………………………………………………………………………………………………………………………………………………………. B-48
Coherex ………………………………………………………………………………………………………………………………………………………………. B-55
De-icer
Calcium Chloride ………………………………………………………………………………………………………………………………………………. B-61

Appendix C
Industrial SWPPP Outline (Draft)

NorthMet Project Transportation and Utility Corridors
Industrial Stormwater Pollution Prevention Plan (SWPPP) Outline
July 2016 Draft
Contents
1.0 Introduction
2.0 Pollution Prevention Team
3.0 Facility Description
3.1 Industrial Activities
3.2 Drainage Areas and Receiving Waters
4.0 Facility Maps
5.0 Assessment of Industrial Activities and Materials
5.1 Assessment of Industrial Activities and Associated Pollutants
5.2 Assessment of Materials and Associated Pollutants
6.0 Best Management Practices (BMPs)
6.1 Non-Structural BMPs
6.1.1 Good Housekeeping
6.1.2 Eliminating and Reducing Exposure
6.1.3 Salt Storage
6.1.4 Chemical Additive Use
6.1.5 Facility Inspection Requirements
6.1.6 Maintenance Requirements
6.1.6.1 BMP Maintenance
6.1.6.2 Equipment Preventative Maintenance
6.1.7 Elimination of Unauthorized Non-Stormwater Discharges
6.1.8 Spill Prevention and Response Requirements
6.1.9 Mercury Minimization Plan
6.1.10Employee Training Program
6.2 Structural BMPs
6.2.1 Erosion Prevention and Sediment Control
6.2.1.1 Vegetative BMPs
6.2.1.2 Stabilization BMPs
6.2.1.3 Structural BMPs
6.2.2 Management of Runoff
6.3 Summary of BMPS
7.0 Benchmark Monitoring Requirements
7.1 Benchmark Monitoring Locations
7.2 Applicable Benchmark Parameters and Benchmark Values
7.3 Monitoring Schedule

7.4 Benchmark Monitoring Records
7.5 Stormwater Monitoring Reports
7.6 Evaluating Benchmark Monitoring Results and Steps for Continued Compliance
7.6.1 Benchmark Values are Not Exceeded
7.6.2 Benchmark Values are Exceeded
8.0 Administrative Requirements
8.1 SWPPP Modifications
8.2 Annual Reporting
8.3 Recordkeeping and Records Retention
List of Appendices
Appendix A NPDES/SDS Permit No. MN TBD
Appendix B Application for Authorization to Discharge Industrial Stormwater
Appendix C Industrial Stormwater Site Inspection Records
Appendix D BMP Maintenance Records
Appendix E Documentation of Evaluation of Non-Stormwater Discharges
Appendix F Spill Records
Appendix G Employee Training Records
Appendix H Benchmark Monitoring Records
Appendix I Industrial Stormwater Monitoring Reports (SWMRs)
Appendix J SWPPP Modification Records
Appendix K Industrial Stormwater Annual Reports