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December 12, 2009
POLYMET DEIS TRIBAL COMMENTS
Citizen groups preparing comments on the NorthMet (PolyMet) DEIS are fortunate to have the benefit of the comprehensive comments submitted (on the earlier PDEIS) by the Native American tribes affected by PolyMet. The tribal groups, specifically GLIFWIC, have professional resources and have filed extensive comments.
Native American Tribes have a unique position in the DEIS because of their status under the 1854 Treaty in which they transferred lands (including PolyMet lands) to the USA but retained rights to hunting, fishing, and gathering on these lands. Their agreement (MOU) with Corp of Engineers and DNR requires tribal comments to be included in the DEIS. They are included as 275+ footnotes in the DEIS.
To assist ourselves and others in preparing comments, we have copied the tribal comments by DEIS section into a separate document. Each footnote is prefaced with enough text description to identify the specific issue on which the footnote comments. Most often this is simply the sentence in which the footnote occurs.
We encountered a problem with footnotes associated with tables. We lack the capability to copy tables from a .pdf format. We suggest printing the tables where supporting material for footnotes is difficult to identify.
The project is a joint effort of NMW and KWCR (Kawishiwi Watershed Concerned Residents - lakeshore property owners in the Kawishiwi Watershed). Volunteers to date have included, Carla Arneson, Jon Green, Clint and Mary Ann Jurgens, Dwight McConnell, Brad Sagen, Joy Schochet, and Kris Wegerson.
Entries should be rechecked for accuracy before inclusion in other comments. Formatting varies by section. Please contact us if you encounter problems or errors.
Brad Sagen, Chair Northeastern Minnesotans for Wilderness
SECTION HEADINGS
1.0 INTRODUCTION 1-1 1.1 BACKGROUND AND LOCATION OF THE NORTHMET PROJECT 1-1 1.2 PROJECT PURPOSE AND NEED 1-3 1.3 PURPOSE OF THE DEIS 1-3 1.4 REGULATORY FRAMEWORK 1-4 1.4.1 National Environmental Policy Act (NEPA) 1-4 1.4.2 Minnesota Environmental Policy Act (MEPA) 1-4 1.4.3 Applicable Regulations 1-5 1.5 AGENCY ROLES AND RESPONSIBILITIES (LEAD AGENCIES, COOPERATING AGENCIES, OTHERS) 1-6 1.6 ORGANIZATION OF DEIS 1-7 1.6.1 Tribal Cooperating Agency Positions Included in the DEIS 1-8 The tribal representatives view themselves as uniquely and disproportionately impacted by mining activities in the 1854 Ceded Territory1 and it has not been possible to reach agreement on a number of conclusions within the DEIS. 1 See e.g. Tribal Position on Chapter 4.10, Section 4.10.3.1 (Proposed Action; Environmental Justice). Rather than limiting inclusion of conflicting conclusions to those that are “major differences of opinion concerning significant impacts” this DEIS includes almost all of the tribal position statements submitted in response to the July 31, 2009 Preliminary DEIS (PDEIS). This is in recognition that the document is a joint state and federal DEIS and that the tribal cooperating agencies have participated in the DEIS development through a memorandum of understanding.2 2 Revised Memorandum of Understanding dated May 19, 2008.
2.0 EIS DEVELOPMENT 2-1 2.1 SCOPING PROCESS 2-1 2.1.1 Identification of Scoping Documents 2-1 2.1.2 Proposed Action and Supporting Documentation 2-2 2.2 ALTERNATIVES IDENTIFIED DURING THE EIS SCOPING PROCESS 2-2 The majority of supporting documentation for the PD and potential impacts of the Project were submitted by PolyMet between July 2006 and July 2009, including documents and technical memoranda and reports as listed in Section 7.0.1 1 The tribal cooperating agencies position is that the public notice of the section 404 permit should be reissued because of significant changes in the Project design that have occurred since the initial public notice in 2005.
2.2.1 Site Alternatives 2-3 2.2.2 Alternative Technologies 2-3 2.2.3 Modified Designs or Layouts 2-3 2.2.4 Alternative Scale or Magnitude 2-3 2.2.5 Alternatives Incorporating Reasonable Mitigation Measures 2-4 2.2.6 Alternatives Incorporated into the Proposed Project 2-4 2.3 ISSUES IDENTIFIED DURING THE EIS SCOPING PROCESS 2-5 2.3.1 Potentially Significant Issues 2-5 The amount of financial assurance associated with reclamation actions cannot be estimated until these actions are understood at a more detailed level of design. This detail is more typically available during the permitting process. Therefore, discussion of financial assurance figures and instruments are not included in the DEIS.2 2 It is the tribal cooperating agencies position that financial assurance can and should be discussed in the draft EIS. Additional details in support of this position can be found in Section 3.1.7 of this EIS.
2.3.2 Other Issues 2-6 2.3.3 Issues Considered But Eliminated During Scoping 2-7 The Final SDD determined that the following topics are not expected to present significant impacts, but would be addressed in the EIS using limited information beyond that provided in the Scoping EAW commensurate with the anticipated impacts. These specific topics are addressed in Chapter 4.0 of this DEIS and include:… 1854 Ceded Territory (Section 4.8).3 3 It is the tribal cooperating agencies position that the Tribes were not involved as Cooperating Agencies during Scoping, or when the Final SDD was issued and that additional consultation and evaluation is needed to determine the degree of impact on the ceded territory as a result of this project.
2.3.4 Issues Incorporated into EIS after Scoping 2-8 During an EIS process, changes to the Project, changes in the regulatory framework, heightened public concern, or availability of new information related to potential impacts, may make it necessary to refine the scope or structure of an EIS. Accordingly, this DEIS will contain greater emphasis on the following issues than was envisioned at the time of the Final SDD:…. Impacts to wild rice.4 4 It is the tribal cooperating agencies position that the tribes were not involved as Cooperating Agencies during Scoping or when the Final SDD was issued. The tribal cooperating agencies position is that although groundwater hydrology and impacts to groundwater, Cultural Resources, and impacts to wild rice were “incorporated” after scoping, impacts resulting from groundwater drawdown and inundation cannot be determined without additional data. Consultation is ongoing with the USACE regarding Cultural resources and impacts to wild rice.
2.4 PUBLIC AND AGENCY INVOLVEMENT DURING EIS DEVELOPMENT 2-8 3.0 PROPOSED ACTION AND PROJECT ALTERNATIVES 3-1 3.1 PROPOSED ACTION 3-1 3.1.1 Mine Site – Location and Ownership 3-1 3.1.2 Mining Activities 3-2 3.1.2.1 Pre-production Mine Development 3-2 3.1.2.2 Open Pit Mining 3-4 3.1.2.3 Drilling and Blasting 3-5
3.1.2.4 Excavation and Haulage 3-6 3.1.2.5 Lean Ore Surge Pile 3-6 3.1.2.6 Rail Transfer Hopper 3-7 3.1.2.7 Other Equipment 3-8 3.1.2.8 Fueling and Maintenance Facilities 3-8 3.1.2.9 Mine Site Water Management 3-9 Both Mine Site non-contact stormwater and process water would be managed at the Mine Site. Non-contact stormwater, the result of precipitation that falls on natural or non-reactive reclaimed vegetated surfaces, would be routed through sedimentation ponds prior to discharge to the Partridge River (RS24, Barr 2007, Draft-02). Process water, which includes precipitation runoff and groundwater (pit dewatering water) that has contacted disturbed surfaces as well as water collected on stockpile liners, would be treated using a combination of membrane separation and chemical precipitation technologies at the WWTF located south of the West Pit (RS29T, Barr 2007).3 3 It is the position of the tribal cooperating agencies that under the proposed project, this facility will need to treat water for hundreds or thousands of years to avoid contamination to the Partridge River.
The effluent from the WWTF would be pumped via the CPS to the Tailings Basin for use as plant make-up water (RS22, Barr 2008) or used to supplement flooding of the East Pit while the East Pit is being backfilled (RS22, Barr 2008). Reuse of the Mine Site process water at the Plant Site would eliminate the need to discharge any process water to surface waters. The solids removed from the Mine Site process water in the WWTF would be reprocessed to recover any potential metals in the Hydrometallurgical Plant as described in Section 3.1.5.2 (RS29T, Barr 2007).4 4 It is the position of the tribal cooperating agencies that under the proposed project, the CPS would need to operate for hundreds or thousands of years in conjunction with the WWTF.
3.1.2.10 Waste Rock and Overburden Management 3-13 3.1.3 Proposed Transport of Ore 3-17 The cars would have hinged sides that drop down when the cars are tipped at the Coarse Crusher for unloading. Ore could escape the confines of the rail cars during transport via two primary routes: 1) Fines through the gaps at the hinges - the Rail Transfer Hopper discharge feeder and track alignment are designed so that cars would be loaded along the centerline. In this loading procedure, ore size may be classified as the car is loaded so that fines would be at the center of the car and the larger ore pieces would be at the edge. The intent is to keep fines from reaching the edge of the car where they would be subject to spillage through the hinge gaps.5 5 It is the position of the tribal cooperating agencies that the amount of ore that could escape from the rail cars would not be small. Taconite pellets currently litter most of the railroad right of way between the plant site and the proposed mine site, confirming that ore can and does spill from the gaps along the side door. Second, fugitive dust escaping through these gaps is also a concern. These very small particles have the potential to cause contamination of soils and wetlands that are located along the rail route, as evidenced by ongoing contamination issues at the Flambeau Mine in Wisconsin. 2) Large pieces of ore over the tops - standard operating procedure would be to use a rubbertired dozer or a front end loader to push any large ore pieces that extend out of the car into or off of the car near the Rail Transfer Hopper because these pieces can damage the Coarse Crusher building and car dumping equipment. In the event that a large ore piece would fall over the top edge of the cars during transit, it would be recovered during routine track maintenance.6 6 It is the position of the tribal cooperating agencies that they are unsure how ore debris can be visually distinguished by rail track maintenance crews from other rocks and ore that litter the embankments. In addition, spillage of ore pieces into the wetlands and creeks that are located along the rail line could not be easily identified and recovered. It is reasonable to assume that some acid drainage and metal leaching would occur along the waterbodies located along the rail line.
3.1.4 Plant Site – Location and Ownership 3-18 3.1.5 Ore Processing 3-19 3.1.5.1 Beneficiation Plant 3-19 3.1.5.2 Hydrometallurgical Plant 3-24 3.1.5.3 Management of Process Waste Products 3-31 3.1.5.4 Plant Site Water Management 3-34 3.1.6 Transport of Consumables and Products 3-36 3.1.7 Project Closure 3-36 3.1.7.1 Building and Structure Demolition and Equipment Removal 3-36 3.1.7.2 Reclamation of Mine Site 3-38 The final Closure and reclamation plan would be updated annually to reflect changes in costs and integration with area mine reclamation/reuse strategies.11 11 As previously discussed, it is the position of the tribal cooperating agencies that the existing Closure Plan is insufficient to allow an adequate assessment of post-closure impacts.
3.1.7.3 Reclamation of Plant Site 3-44 (More) In the long term, the volume of water requiring treatment would decline to the point that the remaining Closure activity may consist of periodic pumping of remaining drainage into tank trucks for transport, treatment and disposal as appropriate, and of inspection of the closed cells to verify integrity of the closure systems. 12 12 It is the position of the tribal cooperating agencies that these pumping and water treatment activities would have to be conducted in perpetuity, and that the cover and liner would require perpetual maintenance.
3.1.8 Post-Closure Activities 3-49 Any additional detail regarding the amount of financial assurance associated with reclamation actions cannot be estimated until these actions are understood at a deeper level of design detail. This detail is more typically made available during the permitting process. Therefore, further discussion of financial assurance figures and instruments are not included in the DEIS. However, the DEIS does recognize that Minnesota regulations require that financial assurance requirements be determined at the permitting phase.13 13 It is the position of the tribal cooperating agencies that financial assurance should be fully explored in the DEIS. This is particularly important given the potential for very long-term/perpetual treatment, maintenance and monitoring that may be needed for the Proposed Action. Because of its experience in expensive cleanups of contamination from many defunct or bankrupt sulfide mines, EPA Region 9 has strongly urged other Regions over the past two years to require financial assurance disclosure in the NEPA process. New national rules for financial assurance are under development by EPA, because “Given the history of adverse environmental effects resulting from some hard rock mines, and the expenditure of public funds used in some cases to address environmental problems caused by mining, EPA believes it is necessary to analyze these factors in the DEIS.” (from InsideEPA.com, Tuesday, August 25, 2009).
Post-Closure and reclamation activities would be expected to be ongoing until such time as the various facility features are deemed environmentally acceptable, in a self-sustaining and stable condition.14 14 It is the position of the tribal cooperating agencies that the potential long term impacts of the project and the potential need for post closure activities would continue for hundreds or thousands of years.
Other continued maintenance activities that would continue throughout Closure and Post-Closure would include repair of stockpile and tailings dike slope erosion, wetland and outflow structure up-keep to ensure they are functioning properly, woody species and tree removal on stockpiles and hydrometallurgical cells with membranes, tailings pond maintenance, and seepage collection from the Tailings Basin.15 15 It is the position of the tribal cooperating agencies that these activities would also have to be conducted in perpetuity.
When PolyMet has completed all reclamation required by the Permit to Mine, they may submit a Request for Release per Minnesota Rules, part 6132.1400. This request would provide the Commissioner of the MnDNR with detailed information on the final reclamation status of the Mine Site.16 16 It is the position of the tribal cooperating agencies that if this project would require perpetual maintenance, it cannot be deemed to be “reclaimed” and would violate the stated goal of Minnesota’s reclamation statute.
3.2 PROJECT ALTERNATIVES 3-50 Some were alternatives considered as required by regulations, others were identified during scoping, and still others were identified after determining that elements of the Proposed Action would cause potentially significant adverse impacts.17 17 Tribal cooperators note that the scoping period for a federal EIS continues until the release of the DEIS. Therefore, new issues that have been identified during the review of the three PDEIS documents must be considered for the DEIS.
3.2.1 No Action Alternative 3-51 This alternative would avoid the environmental impacts associated with the Proposed Action; however, the social and economic benefits from the Project would not occur.18 18 Tribal cooperating agencies disagree with the assumption that the proposed project would only result in social and economic benefits. The environmental impacts of the project on the 100 Mile Swamp, an undisturbed and very high quality wetland complex, would constitute a social impact. Furthermore, economic development that is not centered on heavy industry (tourism for example) would be adversely impacted by the project. At the end of the project life, there would also be negative economic impacts as the surrounding communities deal with the loss of primary employment and economic revenue streams that were dependent on the Project.
3.2.2 Mine Site Alternative 3-51 3.2.3 Tailings Basin Alternative 3-52 If it were determined upon further analysis during permitting, or during operational monitoring, that pretreatment were necessary prior to discharge, a treatment facility would be installed.19 19 It is the position of the tribal cooperators that water treatment of the discharge would be required to comply with the wild rice water quality standard. The Partridge River contains several wild rice beds immediately downstream of the proposed discharge point.
(3) Increased rock buttress material… also includes demonstration testing of a Permeable Reactive Barrier (PRB)… If successful, a permanent PRB could be built as a vertical unit through the flow path of the seepage from the Tailings Basin and/or a horizontal surface unit (i.e. constructed wetland). The PRB, if built, may require periodic recharging (Barr 2009, PolyMet Mitigation in Tailings Basin Area – Details in Combination Evaluation, TBM-17 Permeable Reactive Barrier).20 20 It is the position of the tribal cooperating agencies that the DEIS should include explicit estimates of how often “periodic recharging” would need to occur.
3.2.3.1 Tailings Basin Alternative Development Process 3-54 The Tailings Basin Alternative resulted from the comprehensive mitigation planning effort by the co-lead agencies, and included input from all Cooperating Agencies and consulting tribes.21 21 Tribal cooperating agencies note that although they participated in the identification of potential mitigation measures for the tailings basin, they did not participate in the development of the tailings basin mitigation design. In addition, it is the position of the tribal cooperators that an untreated discharge of contaminated tailings basin water to the Partridge River in order to dilute and dispose of tailings basin water would have environmental impacts that must be avoided in order to adequately protect the environment.
3.2.4 Alternative Considered But Eliminated 3-62 3.2.4.1 Alternative Sites 3-62
Table 3.2.4 E7 Underground Mining (p. 3-64) (Description – from table) Not economically viable. The rate of ore production of an underground mine would not support the processing rate necessary to economically process the low grade ore, and therefore would not meet the Purpose and Need of the Project. This reduced scale of production ties into the elimination of the modified scale or magnitude alternative discussed below. Additionally, the ore deposit is shallow and broadly distributed throughout the Mine Site; which increases the safety hazards due to the risk of the mine ceiling collapse unless a sizable amount of ore was left in place and not recovered.22 22 It is the position of the tribal cooperating agencies that this alternative was eliminated prematurely and without sufficient consideration. They note that analysis of unquantified environmental impacts, values, and amenities have not been evaluated as required by CEQ regulations. A study of this particular deposit was performed by U.S. Steel that recommended underground mining. By examining cross-sections showing the distribution of ore by depth, it appears that there are substantial ore reserves at depths that likely could not be accessed by the proposed open-pit mine. The ecological costs of open-pit mining and above-ground disposal of tailings and waste rock are immense. This ecological cost, combined with the most current understanding of deposit ore grades and reasonably possible metals
3.2.4.2 Alternative Technologies 3-68 Evaluating alternative processing technologies to the Proposed Action was not carried forward in the DEIS since it was determined during the Final SDD process that alternative metal extraction technologies would not have significant environmental benefits over the proposed hydrometallurgy technology. The following analysis is included in response to public inquiries regarding the feasibility of underground mining the NorthMet deposit.23 23 Tribal cooperating agencies disagree with the rationale used to eliminate underground mining as an alternative. See table 3.2-4 for details.
3.2.4.3 Modified Designs or Layouts 3-69 3.2.4.4 Modified Scale or Magnitude 3-70
4.0 EXISTING CONDITIONS AND ENVIRONMENTAL CONSEQUENCES 4.1 WATER RESOURCES 4.1.1 Existing Conditions 4.1.1.1 Meteorological Conditions 4.1.1.2 Groundwater Resources The water table is primarily located within the surficial aquifer, but is likely located within the bedrock in areas of local bedrock highs.1
1 It is the position of the tribal cooperating agencies that the lack of groundwater level data in the surficial aquifer and in the bedrock, except in the immediate vicinity of the mine pits, does not allow for a full or complete characterization of the watertable or the potentiometric surface in the bedrock or the surficial aquifer. The current bedrock groundwater model calibration to shallow wetland piezometers cannot be justified. The lack of groundwater level data at the tailings area except in the immediate area of the tailings piles prevents complete characterization of water tables, potentiometric surfaces, and groundwater flow direction. The dramatic scarcity of hydrologic data for the PolyMet project, both at the mine site and at the site of the tailings basins has been repeatedly recognized by hydrologists at technical meetings. Limited data collection to fill in the data gaps has recently been conducted and in general not incorporated into hydrologic analysis of the mine or plant site.
These bogs are isolated from the underlying groundwater, receiving virtually all of their water and nutrient input from precipitation. They receive essentially no groundwater inflow and have extremely low seepage rates to the underlying surficial aquifer.2 2 Tribal cooperating agencies strongly disagree with this conclusion. It is the tribal cooperating agencies’ position that there is no data to substantiate this assumption. This assumption is based on incidental observation and the analysis of aerial photography, which is by its nature imprecise (Adams, John and Micheal Liljegren. 2009 “Additional PolyMet peatland data / information.” email communication to Stuart Arkley. February 1, 2009). Tribal cooperating agencies note that the wetland delineation indicates the presence of several hundred acres of cedar swamps and tamarack wetlands. These vegetation types, by definition, rely on an influx of groundwater to support them. Finally, tribal cooperating agencies note that the wetland delineation does not encompass all wetlands that are likely to be affected by the project. Because no initial determination of the projects area of influence on wetlands was made, the site field surveys of wetland and other vegetation was limited to little more than the area within the project fence. The existing characterization of wetland and other vegetation does not cover even one-half the area that might reasonably be expected to be impacted by secondary impacts of the mine due to disruption of the existing hydrology. Around the tailings basin virtually no wetland delineation has taken place although wetland impacts from inundation are likely to occur.
No data were available regarding the storage parameters for the surficial deposits.3 3 It is the tribal cooperating agencies’ position that any conclusions based on this aquifer test data have a great deal of uncertainty given the variability in the results.
Recent hydrologic investigations (Barr 2009, Technical Memorandum: Results of Tailings Basin Hydrogeological Investigation) indicate that the average flow through the aquifer downgradient of the Tailings Basin (i.e., flux) may be as low as 155 gpm with an estimated recharge rate of approximately 0.3 inches per year (Barr 2009, Technical Memorandum: Results of Tailings Basin Hydrogeological Investigation).4 4 Tribal cooperators note that hydrologic data indicates that this aquifer is saturated by tailings discharge water. It is the tribal cooperating agencies’ position that therefore, it is not possible for recharge from precipitation to occur.
Baseline Water Quality Page 4.1-13 and 4.1-14 …Based on the parameters that were monitored in the Cell 2E pond, it appears that passage through the LTVSMC tailings reduces the average concentrations of arsenic, fluoride, and molybdenum, although it is difficult to discern to what extent these reductions are simply attributable to the effects of dilution. The concentrations of several other parameters, such as calcium, manganese, nickel, and total dissolved solids, increase as they seep from the tailings pond to the toe of the Tailings Basin. …Potential exceedances for beryllium correspond to situations where the laboratory detection limits (<1.0 μg/L) is greater than the evaluation criteria (0.08 μg/L).5 5 It is the Tribal cooperating agencies’ position that the existing LTVSMC tailings are contributing substantially to the level of constituents observed in the groundwater. Unfortunately the modeling of PolyMet contaminants at the basins does not take these or other existing constituents adequately into account (RS74 and TB-14). The result of this oversight is that the contaminant modeling done by PolyMet comes to the illogical conclusion that seepage water from PolyMet, after passing through both LTVSMC and PolyMet tailings, will be cleaner than the existing seepage that is passing only through the LTVSMC tailings. According to PolyMet’s consultant “the predicted concentration of seepage from the PolyMet basin is lower than the actual measured concentration of existing seepage" (TB-14, page 9). It is unclear how the addition of mine waste to the basins would cause seepage water quality to improve.
Page 4.1-19 Based on the investigations and laboratory analyses to date, which includes sampling at 7 monitoring wells, 14 surface discharges, 12 internal waste streams, 6 downstream surface water monitoring stations, and visual observation and limited field analyses at 33 seeps at or near the LTVSMC Tailings Basin, there has not been any documentation of any off-site contamination, and the extent of on-site contamination from the legacy sites appears to be limited to localized soils and possibly groundwater.6 6 Tribal cooperating agencies note that additional legacy issues exist. Over the many decades of operations at the tailings basin, thousands of gallons per minute of tailings basin water have been discharged throught the bottom of the basin, into groundwater. This water has then moved down gradient and into surrounding wetlands and as stated in the water quality section below, ultimately reaches the Embarrass River. It is the tribal cooperating agencies’ position that despite very limited recent groundwater sampling that shows groundwater contamination at the property line and at private wells north of the basin, the full extent of the contaminant plume and the existing contamination to groundwater has not been defined.
4.1.1.3 Surface Water Resources
Page 4.1-21 The Partridge River above Colby Lake (USGS Station #04015475) is the gaging station that best represents flows from the Project area, but only has 10 years of flow records available (1978-1988).7
7 It is the tribal cooperating agencies’ position that the baseline data for both the Mine Site and the Tailings Basin are inadequate. The baseline data for both the mine site and the tailings basin are sparse. A comparison of hydrologic data that was collected for two other projects in the region (GLIFWC letter to Jon Ahlness and Stuart Arkley, February 6, 2009) demonstrates that the PolyMet project is data-poor in the area of basic hydrology. The use of flow data on the Partridge River from a site twenty years and seventeen miles distant from the proposed project does not provide sufficient information to allow a full assessment of the hydrologic and environmental impacts of the project on the Partridge River. Tribal cooperating agencies have requested that additional data be collected.
The discharge statistics for the USGS Station above Colby Lake as well as modeled flow at six other upstream locations (SW-001, SW-002, SW-003, SW-004, SW-004a, and SW-005) on the Partridge River (Figure 4.1-11) are presented in Table 4.1-13.8
8 As previously discussed, it is the tribal cooperating agencies’ position that these patterns are not representative of the Partridge River near the mine site. The gauging station is seventeen miles from the mine site and the data from that station are twenty years old and therefore, unlikely to be representative of current conditions at the mine site.
Page 4.1-33 Waters that contain wild rice are discussed later in this section of the DEIS.9
9 It is the tribal cooperating agencies’ position that, as stated in Minn. 7050, the 10 mg/l of sulfate standard for wild rice applies for waterbodies where wild rice if found. The PCA has used this approach in past permitting activities (MINNTAC Schedule of Compliance, 2008). The10 mg/l sulfate standard also applies to the Partridge River below Colby Lake where several wild rice beds are located. Tribal cooperating agencies note that the Army Corps has not completed consultation on cultural issues with the potentially affected tribes. This delay means that the extent of existing wild rice beds has not been fully characterized.
Page 4.1-46 Additional physiological research is needed to better understand the effect of sulfate on natural wild rice during various life stages.10
10 It is the tribal cooperating agencies’ position that extensive research in Minnesota has demonstrated that healthy and viable wild rice beds occur in waters with less than 10 mg/l of sulfate. While it is the prerogative of the PCA to seek a change in water quality standards anytime it chooses, it is the tribal cooperating agencies’ position that the standard, as currently in place, must be enforced.
4.1.2 Impact Criteria 4.1.2.1 Hydrologic Alteration of Streams, Lakes and Aquifers Impact Criteria Page 4.1-50 The deviation from existing conditions, based on modeling, in the mean values of the hydrologic parameters help determine the degree of impact to stream ecology.11
11 It is the tribal cooperating agencies’ position that there is no mechanism to accurately develop the data listed above. Field data collection is spotty or non-existent and the numbers used in this DEIS are derived from the MODFLOW groundwater model and XP-SWMM model. It is important to note that the MODFLOW model was developed to assess the rates of mine pit inflow and as such, the results it gives for areas outside the mine pit footprint are unsupported by data. The XP-SWMM is based on stream gage data that is 17 miles and 20 years distant from the proposed project. Therefore, the above listed parameters calculated for the Partridge River have little data to support them.
4.1.2.2 Water Quality Impact Criteria 4.1.2.3 Waters That Contain Wild Rice 4.1.2.4 Mercury Impact Criteria 4.1.3 Environmental Consequences 4.1.3.1 Proposed Action
Page 4.1-54 The Uncertainty Analysis was not applied to all water quality parameters, but only to a subset of parameters determined to be the most critical by the resource agencies.12
12 Tribal cooperating agencies take the position that the contaminant modeling for the project has not been adequately vetted and consequently produces results that are illogical. For example, the contaminant modeling for the tailings basins (RS74B and TB-14) proposes that adding PolyMet tailings to the existing LTVSMC tailings will improve the quality of seepage coming from the basins for some parameters. The assumption (TB-14 of July 2, 2009, page 9) that PolyMet seepage water from the basins will be of better quality than the current seepage water results in an unexpected modeling result. The modeling proposes that the more PolyMet seepage that PolyMet releases from the basins, the better the water quality will be for Al, Mn and Fe in the Embarrass River (see Tables in TB-15 of June 24, 2009). It appears that the modeling at the basins does not appropriately account for leaching from the LTVSMC tailings when predicting future seepage quality.
Page 4.1-55 Mining would end in approximately Year 20 and all mine dewatering activities would cease…At this time, a limited amount of process water from the Mine Site (long term flow after Year 30 estimated at 227 gpm) would still be generated (e.g., collected stockpile leachate), routed to the WWTF, treated, and pumped to the East Pit, where it would flow through a passive wetland treatment system before draining to, and helping to fill, the West Pit.13
13 It is the tribal cooperating agencies’ position that the long-term effectiveness of the wetland treatement system has not been demonstrated by the applicant (see discussion of constructed wetlands below).
The collected Hydrometallurgical Residue Cell drainage, which previously was being reused at the Plant Site, would be pumped/trucked to the WWTF for treatment until approximately Year 34, when the drainage is expected to end.14
14 It is the tribal cooperating agencies’ position that this 34 year timeframe is unlikely to be correct. Because all cap and liner systems leak, some pumping of water that enters the hydrometallurgical residue cells would be needed in perpetuity. This would be particularly true as the cap ages and develops additional leaks.
Page 4.1-56 PolyMet would continue to collect and treat leachate from the permanent waste rock stockpiles at the WWTF until monitoring shows that treatment is no longer necessary to meet water quality standards.15
15 Tribal cooperators note that stockpile leachate is predicted to not meet water quality standards for thousands of years (Table 4.1-45).
Page 4.1-56 The volume of seepage from the Tailings Basin is expected to decrease slowly over time, but, with no proposed dry cap, long-term groundwater seepage would be expected.16
16 It is the tribal cooperating agencies’ position that water quality and hydrologic impacts to wetlands and the Embarrass River under this proposed alternative would be perpetual.
Page 4.1-56/57 These models were constructed chiefly to assess operational conditions, specifically dewatering of the proposed mine pits, with the intent of estimating the range of inflow to the pits for water balance purposes and water quality modeling, and determining groundwater mounding and internal flow characteristics at the Tailings Basin. Table 4.1-33 summarizes the assumptions and input for the three different MODFLOW models developed for the Project (i.e., Regional Model, Mine Site Model, Tailings Basin Model).17
17 It is the position of the tribal cooperating agencies that hydrologic characterization using MODFLOW models was done for the immediate area of the mine pit and the tailings pile only. There are no groundwater models that were designed to characterize the watertables, the potentiometric surface in the aquifers, fluxes to rivers and streams or to predict impacts to the water tables or surface waters. The MODFLOW groundwater model at the tailings area is restricted to the tailings pile and cannot be used to characterize groundwater flow direction, the watertables, the potentiometric surface in the aquifers, fluxes to rivers and streams or to predict mounding impacts to the water tables or surface waters. Data driven models need to be developed and these impacts need to be predicted and evaluated.
Page 4.1-59 Therefore, in the following discussion, applicable MODFLOW model results will be described except where they have been superseded by empirical observations.18
18 It is the tribal cooperating agencies’ position that the MODFLOW model does not provide credible data outside the footprint of the mine pits. The view that mine pit dewatering impacts will be very limited or non-existent (Adams, John and Michael Liljegren. 2009 “Additional PolyMet peatland data / information.” email communication to Stuart Arkley. February 1, 2009) is based on the assumption that there is little or no connection between the bedrock and surficial aquifers (GLIFWC 2009, Memorandum to Jon Ahlness and Stuart Arkley: Photographic evidence for pit impacts to wetland hydrology. April 24, 2009). However, the scant data that does exist characterizing mine site hydrology suggests that there may be substantial connection between the bedrock and surficial aquifers. Such a connection would mean that dewatering of the mine pits could cause significant drawdown of the watertable in the surficial aquifer. Data presented in RS02 indicates that ammonia can be found in deep boreholes. Section 3.3 Analytical Results, Pg.10 of RS02 states: "The water sample from boring 05-407M exceeded the criteria for ammonia (1,900 ug/l)”; and goes on to state, “The sample from boring 05-401M exceeded criteria for ammonia (610 ug/l)."; and “Water quality criteria were exceeded for ammonia, aluminum, copper, and silver in both boreholes.”; and concluded that, “The presence of ammonia in the deep boreholes may indicate that the water in the borehole came from the shallow surficial deposits. Ammonia is not typically found in deep bedrock systems but is common in wetland environments." Similarly, technical document RS10 concludes: “The presence of ammonia nitrogen in the samples likely indicates that there is a hydraulic connection between the bedrock aquifer and the surficial aquifer; however, the nature of this connection cannot be determined at this time." Furthermore, tritium data also presented in RS10 suggests that deep water is of relatively recent origin. While professional opinion can be very useful in predicting mine impacts, it must be tempered with site specific knowledge based on quantitative data. Models, using assumptions based on professional judgment, that adequately characterize the hydrology of both the mine site and the tailings site must be developed so that hydrologic data can be integrated into the best characterization of the area’s hydrology possible. Such models depend on the reasonable use of professional judgment but require a significant amount of real, site-specific data. The expertise of both local hydrologists and hydrologists with experience in other settings is needed to develop a plan for hydrologic data collection and for formulating the appropriate models to integrate the hydrologic data.
Page 4.1-61 In this hydrologic setting, however, it is not practical to gather such locally variable input data for a MODFLOW model.19
19 Tribal cooperating agencies disagree with this assumption. It is the tribal cooperating agencies’ position that in order to adequately predict potentially significant environmental impacts, hydrogeologic data must be collected that can be used as input to a MODFLOW model. Tribal cooperating agencies contracted with the United States Geological Survey (USGS) to review the uncertainty of the MODFLOW model and provide recommendations on how the model could be improved. The USGS report was submitted to the lead agencies in February of 2009 (USGS 2009, Letter Report reviewing PolyMet ground-water model. January 29, 2009). Tribal cooperating agencies organized meetings between USGS staff and participants in the EIS, including the applicant, to openly discuss all issues related to the USGS report, the MODFLOW model and the implications for the proposed project. The conclusions of the report and the meetings should be implemented so as to produce a useful model of project site hydrology. Tribal cooperating agencies believe that impacts to surface waters, groundwater, and wetlands for a project of this complexity demand a scientific, data driven approach rather than one based solely on professional opinion. Finally, it is the tribal cooperating agencies’ position that a robust groundwater model must be developed for this project in order to adequately characterize the potential impacts of various project alternatives to natural resources.
MnDNR has monitored several other lakes across the Mesabi Iron Range over the past several decades and the data show little, if any, effects from mine pit dewatering (Adams 2009).20
20 It is the position of the tribal cooperating agencies that, as previously indicated, the empirical observations in the Adams 2009 email are insufficient to support the conclusions in the paper. Vegetation data suggest that a significant groundwater-surface water connection exists. It is the tribal cooperating agencies’ position that a more robust groundwater model must be developed for this project in order to adequately characterize the potential impacts of the various project alternatives to natural resources.
Page 4.1-61/62 The existing information strongly suggests that the probability is very low that extensive hydraulic connectivity exists to allow significant impacts to wetlands and other surface water features at the Mine Site (Adams and Liljegren 2009; and Adams 2009).21
21 It is the position of the tribal cooperating agencies that, as previously indicated, the empirical observations in the Adams 2009 email are insufficient to support the conclusions. The evidence presented in the email can be interpreted to indicate substantial impact of the Peter Mitchell Pits on adjacent lakes. However, it is the tribal cooperating agencies’ position that aerial photography, without ground verification or georeference is an exceedingly imprecise method for determining water levels in lakes and wetlands (GLIFWC 2009, Memorandum to Jon Ahlness and Stuart Arkley: Photographic evidence for pit impacts to wetland hydrology. April 24, 2009).
Given the lack of water tracks and photographic evidence of impacts to nearby surface water features, the Mine Site peatlands appear to be much more bog-like than fen-like (Adams 2009).22
22 As previously stated, it is the tribal cooperating agencies’ position that the above referenced email (Adams 2009) used inadequate methods for determining impacts to surface water features.
Section 4.2 discusses recommended wetland monitoring at the Mine Site.23
23 It is the tribal cooperating agencies’ position that the DEIS should not rely on future monitoring to detect impacts as a substitute for the development of data and analyses that would reasonably identify and predict those impacts as part of a DEIS.
Page 4.1-66 The groundwater quality modeling discussed below assumes these mitigation measures are successfully implemented.24
24 Tribal cooperators strongly disagree with the assumptions used in the groundwater quality modeling for the mine site. It is the tribal cooperating agencies’ position that relying on the effectiveness of a technology with highly variable outcomes (limestone treatment) in calculating long-term water quality is not a conservative approach. The DEIS should provide a range of water quality results including the groundwater quality under a scenario where lime treatment and covering the Virginia Formation wall is ineffective.
Page 4.1-67 The waste rock stockpile drainage would continue to receive chemical treatment at least until the West Pit fills around Year 65. At that time, water quality monitoring of the West Pit overflow would determine whether continued treatment would be necessary.25
25 Tribal cooperating agencies note that the analysis of stockpile leachate collection (Table 4.1-45) indicates that collection would be needed for 2000 years in order to avoid violations of water quality standards. Furthermore, periodic collection of wastewater from the hydrometallurgical tailings facility would have to continue in perpetuity. Therefore, it is the tribal cooperating agencies’ position that the WWTF would also have to operate for a minimum of 2000 years. Tribal cooperating agencies suggest that this does not meet the Minnesota goal of maintenance free closure.
Page 4.1-73 Solute transport was evaluated along six simulated flow paths and at two key evaluation points – in groundwater at the PolyMet property boundary and in groundwater immediately upgradient from the Partridge River (Table 4.1-39; Figure 4.1-25).26
26 Tribal cooperating agencies note that the property boundary has not been defined for this project. Therefore, it is the tribal cooperating agencies’ position that the Dunka Road should be used as an evaluation point. Corresponding information for that evaluation point must be included in Table 4.1-39.
Page 4.1-94 Based on the results of the deterministic modeling, the Proposed Action would have relatively little adverse effect on groundwater quality downgradient of the Tailings Basin. Predicted aluminum concentrations would be within the range of natural baseline concentrations for the area, within the range of concentrations found at nearby residential wells, below the upper end of the USEPA secondary MCL range, and would not pose a risk to human health.27
27 It is the position of the tribal cooperating agencies that groundwater contamination from the previous mining activities is still an issue near the LTVSMC tailings basin more than twenty years after operations ceased. Because of the limited distribution of monitoring wells, the extent of the contaminant plume is not known. However, recent well data show that the plume extends in some areas at least as far as private wells along the Embarrass River. In the wells that do exist near the tailings basin, pollutants including iron, sulfate, manganese, aluminum, and fluoride exceeded drinking water standards. Recent wells near the northern property line show substantial contamination of the groundwater aquifer (Barr 2009, Memorandum: Results of Tailings Basin Hydrogeological Investigation. June 2, 2009). The baseline data on which to base estimates of the impact of the proposed project on water quality at the mine site and the tailings basins is insufficient. The existing analysis for the PolyMet project calculates the additional constituents that the project will add to groundwater but is unable to realistically estimate what the resulting water quality will be because background water quality has not been incorporated into the estimates. Private domestic wells lie between the tailings basin and the Embarrass River where tailings basin discharge water is expected to ultimately discharge. Some of the sampled private wells have contaminants at levels several times the drinking water standard (Barr 2009, Memorandum: Results of residential well sampling north of LTVSMC tailings basin. January 27, 2009) Samples from these wells show exceedances of manganese and close to exceedances of the arsenic standard. Once a groundwater flow model is developed that would show the direction and rate of groundwater flow, that pattern of flow should be used to plan a groundwater sampling scheme that would map the extent of the existing contaminant plume. This data and analysis should then feed into estimates of how the proposed project would interact with existing contamination. The combination of existing conditions with impacts due to the proposed project would show what groundwater quality can be expected during and post project.
Page 4.1-98 The Proposed Action would affect the Upper Partridge River by reducing flows, which in turn could affect river morphology, as well as impacting a portion of the Partridge River’s 100-year floodplain. These potential effects are evaluated below.28
28 Tribal cooperating agencies note that little or no baseline data was collected to develop the modeling described in this document. Therefore, it is the tribal cooperating agencies’ position that the model results cannot be used with confidence and do not allow an adequate assessment of environmental impacts.
Page 4.1-102 Overall these effects are expected to be minor as the base flow in the Partridge River is naturally low (i.e., often less than 2 cfs during the winter and during summer dry periods).29
29 Tribal cooperators strongly disagree with the conclusions in this section. The available data does not support these conclusions.
Page 4.1-102/3 Therefore, any sediment deposition that may occur would likely only be temporary and would be flushed when larger storms occurred. No other significant effects on river morphology would be expected.30
30 It is the tribal cooperating agencies’ position that the available data do not support the conclusions presented in this section. The impacts predicted by technical reports (RS73B) to the Partridge River are primarily reduction in base flow due to mine pit dewatering and those impacts are predicted by the MODFLOW model. MODFLOW modeling in (RS22-Appen.B) forms the foundation for the predicted impacts. The MODFLOW model (RS22 Appen.B) is not calibrated to a data set representative of the area and predicts fluxes to the Partridge River based an a non-unique solution. A differently formulated and calibrated MODFLOW model could predict much higher inflow to the PolyMet pits and therefore, show greater impacts to stream baseflow The surface water model (SWMM) used for predicting impacts is calibrated to Partridge River flows from 1978 to 1988, seventeen miles downriver of the mine site. During the period of record, the Peter Mitchell pits were dewatered with unknown effects on the river flow data. According to technical documents (RS73A, page 21) the flow record at the Partridge River gage above Colby Lake (USGS #04015475) may have been impacted by mine discharges on the north branch. The monthly average flow recorded at this gaging station during 1978-1988 varied between a minimum of 1.3 cubic feet per second and a maximum of 454 cubic feet per second. The discharges from the Peter Mitchell Pit could account for up to 34 cubic feet per second. Since the timing, duration and location of mining discharges may be different now than during 1978-1988, the present hydrologic regime of the Partridge River may not be well represented by the period of record at USGS #04015475.
Page 4.1-107 Under existing condition, seepage from the LTVSMC Tailings Basin (Cells 1E/2E) is estimated at approximately 900 gpm (2.0 cfs) (Hinck 2009).31
31 It is the tribal cooperating agencies’ position that there will be surface water discharge to the Embarrass River. Aerial photography and state Public Waters inventory maps indicate that there is currently a direct surface water connection between the northwest corner of cell 2W and the Embarrass River. Aerial photos show that water discharging from the tailings basin follows a natural channel westward, through existing wetlands and intersects a channel that leads directly to the Embarrass River.
Page 4.1-111/2 The potential effectiveness of the proposed constructed wetland is evaluated below, and then, based on those conclusions, the likely water quality of the West Pit overflow is evaluated.32
32 Tribal cooperating agencies believe the characterization in the previous paragraph is misleading. First, as previously indicated, the WWTF would need to operate for a minimum of 2000 years in order to treat leachate from the stockpiles. Second, the effectiveness of the passive wetland treatment system has not been demonstrated and it is likely that the wetland treatment system would not function as the applicant has suggested (see discussion below). Finally, the long term water quality of the pit lake is a concern. It is unlikely that this water would ever meet surface water quality standards. It is the tribal cooperating agencies’ position that the DEIS should discuss the implications of leaving a polluted pit lake at this site in perpetuity.
Page 4.1-113 Constructed wetlands performance, however, is not sufficiently reliable to function as the primary treatment measure for assuring consistent year-round compliance with water quality standards.33
33 Based on these uncertainties, it is the tribal cooperating agencies’ position that primary water treatment at the WWTF would need to continue for thousands of years. This does not meet the Minnesota goal for maintenance free closure.
Page 4.1-114 Pit overflow would reach the Partridge River and downstream of the confluence of the South Branch Partridge River) based on deterministic modeling (Table 4.1-62).34
34 Tribal cooperating agencies strongly disagree with this approach. It is the tribal cooperating agencies’ position that all waters of the state are protected by Minnesota water quality standards and using this unnamed water as a mechanism to dilute mine related contamination is not appropriate. In addition no flow information for this unnamed water is available.
Page 4.1-115 Section 4.1.3.5 discusses potential mitigation measures that address the potential for exceedances of surface water standards in the West Pit overflow.35
35 Tribal cooperators note that the previous paragraph is speculative. It is the tribal cooperating agencies’ position that because of continued inputs from the stockpiles, the tailings basins, and the pit walls, the pit lake could exceed surface water quality standards for thousands of years. Tribal cooperating agencies note that 20 feet of pit wall will never be submerged and as such constitute a perpetual source of mine related contaminants.
Page 4.1-117 All parameters are expected to meet surface water standards under all flow conditions for all mine years as is predicted for the Upper Partridge River and Colby Lake.36
36 It is the tribal cooperating agencies’ position that contaminants from the project would contribute to exceedances of standards below Colby Lake. Wild rice beds are located on the Partridge River immediately below Colby Lake. Therefore, the State of Minnesota wild rice standard for sulfate of 10 mg/l should apply along all of the Lower Partridge River.
Page 4.1-120 During average and high flow conditions, discharge from Pit 5NW (nearby inactive taconite pit) and natural surface runoff from the watershed represent the primary sources of sulfate, respectively. 37 37 It is the tribal cooperating agencies’ position that because the Embarrass River already exceeds water quality standards, it would be difficult to permit the addition of additional contamination from new or expanded sources.
In summary, water quality modeling indicates that the Proposed Action is expected to meet surface water standards in the Embarrass River.38
38 It is the position of the tribal cooperating agencies that surface water quality at the project has been poorly characterized or left uncharacterized. The limited data that exist suggest that surface waters are already adversely impacted by mining activity. Mercury, sulfate and specific conductance have exceeded Minnesota surface water criteria in surface water samples collected near the tailings basin proposed for use by PolyMet, at nearby Area Pit 5, and mercury exceeds surface water criteria in the Partridge River downstream of Colby Lake. However, no water samples have been collected from lakes near the tailings basin (Hiekkilla, Mud, Kaunonen, or Hay Lakes) to determine if the pollutants found in the surface and groundwater at the existing tailings pile have caused contamination of those waterbodies. Contaminant transport modeling suggests that the PolyMet Project will cause manganese, aluminum and sulfate to exceed standards.
Page 4.1-124 Nevertheless, there is some uncertainty as to whether the West Pit overflow would meet the Great Lakes Initiative standard for mercury and additional analysis of this issue is recommended.39
39 Tribal cooperating agencies agree that further analysis should be conducted. Tribal cooperating agencies take the position that the analysis should be incorporated in the DEIS so that environmental impacts can be predicted and reviewed by the public.
Page 4.1-125/6 At the Mine Site, there are few wetlands located between the waste rock/lean ore stockpiles and the Partridge River, so there is little opportunity for sulfate wetland interactions.40
40 As previously indicated, this assumption is based on a single email (Adams 2009). Tribal cooperating agencies have reviewed this email and found that it does not use methods suitable for prediction of impacts. Further detail on the position of the tribal cooperating agencies is available in section 4.2.
Page 4.1-126 Therefore, under the Proposed Action, the risk of increased sulfate loadings from the Mine Site promoting methylation of mercury in wetlands is expected to be low.41
41 Tribal cooperating agencies have found extensive rice beds in the Lower Partridge River and take the position that methylation of mercury may be significant in the Partridge River watershed.
Page 4.1-127 The Proposed Action would generally reduce flows in the Partridge River, but would not be expected to result in increases in flow fluctuations that can promote mercury methylation.42
42 It is the tribal cooperating agencies’ position that the data used to support this conclusion is inadequate.
Page 4.1-128 Mercury monitoring is recommended to determine if elevated mercury concentrations are found in the West Pit (see Section 4.1.3.5 for a discussion of recommended monitoring measures).43
43 Tribal cooperating agencies disagree with this approach. It is the tribal cooperating agencies’ position that the determination of the final water quality of the west pit should be included in the DEIS so that potential water quality impacts to Lake Superior can be characterized.
Page 4.1-129, Table 4.1-68 Reduce average flow by approximately 1.5 cfs. Minimal reduction in annual 7-day low flow (~0.1 cfs). No significant effect on river morphology or 100-year floodplain.44
44 Tribal cooperating agencies disagree with these conclusions because there is insufficient data.
Closure is predicted to initially exceed standards for several parameters, but water quality is expected to improve over time and exceedances could be mitigated.45 45 Tribal cooperating agencies note that the west pit is predicted to violate surface water standards for all years that predictions were made.
Reduce average flows by as much 10.5 cfs (9%) and increase the frequency of low flows.46 46 Tribal cooperating agencies disagree. There is not enough data to support this conclusion.
4.1.3.2 No Action Alternative
Page 4.1-130, Table 4.1-68 All parameters predicted to meet all surface water quality standards during all flow conditions for all mine years.47 47 Tribal cooperating agencies disagree. The wild rice standard for sulfate and the Lake Superior standard for mercury would be exceeded.
Groundwater seepage from the Tailings Basin would generally meet groundwater evaluation criteria with the possible exception of aluminum. Aluminum is a USEPA secondary MCL standard for managing aesthetic considerations and not to protect human health, and is naturally found in elevated concentrations in the Project area.48 48 Tribal cooperating agencies disagree. Existing contamination has not been considered in the analysis.
All parameters predicted to meet surface water quality standards during all flow conditions for all mine years.49 49 Tribal cooperating agencies take the position that the wild rice sulfate standard is applicable and would be exceeded.
Page 4.1-131 The monitoring data that are available do not suggest regular exceedances of groundwater evaluation criteria at downgradient evaluation points (e.g., property boundary).50 50 It is the tribal cooperating agencies’ position that data collected in 2009 show that private wells north of the basin have been impacted by historic tailings basin effluent. Although two additional groundwater samples north of the basins collected in 2009 indicate that exceedances exist at the property boundary, the full extent of the contaminant plume has not been defined.
The Closure Plan does not propose any remediation of groundwater seepage from the Tailings Basin.51 51 Tribal cooperating agencies note that there is no up to date closure plan for the proposed project. It is the tribal cooperating agencies’ position that a closure plan is needed to evaluate long term environmental impacts and to inform calculations of financial assurance that would be needed for the project. For more information refer to section 3.1.7.
Page 4.1-131/2 It is difficult to estimate what effect any remediation activities may have on groundwater quality at the Tailings Basin. Over time, groundwater quality would be expected to approach baseline conditions, but the relatively high concentrations of aluminum, iron, and manganese currently found downgradient of the Tailings Basin may reflect natural conditions in this area.52 52 It is the tribal cooperating agencies’ position that the available data does not support this claim. In addition, a basic assumption (i.e. plug flow [TB-14, July 2, 2009, page 9]) of the contaminant transport modeling at the basin (RS74) assumes that all constituents in the groundwater are the result of past and current seepage from the basins.
Page 4.1-132 Corrective actions at these sites, as may be required by the reissuance of existing NPDES/SDS permits, could reduce sulfate loadings and may enable sulfate concentrations in the Embarrass River near PM-13 to eventually approach that found at the upstream location PM-12.53 53 The tribal cooperating agency position on this issue is clear. The wild rice standard applies to all waterbodies where wild rice is found to be growing. It is the expectation of the tribal cooperating agencies that the PCA will enforce the standard accordingly.
4.1.3.3 Mine Site Alternative
Page 4.1-134, Table 4.1-69 Groundwater seepage would exceed aquifer flux capacity resulting in continued seepage upwelling and wetland impacts, but at a reduced level relative to existing conditions as Tailings Basin continues to dewater and reach a relatively steady state.54 54 The tribal cooperators take the position that the basins will drain until seepage equals precipitation at which point the hydrology will have returned to approximately pre-basin conditions. As seepage declines, as has been already seen over the past 8 years, surrounding wetlands will begin to recover from the previous hydrologic impacts.
Anticipate slight improvement in groundwater quality as Areas of Concern are investigated and remediated as appropriate.55 55 The tribal cooperators take the position that the assumption of plug flow in the contaminant modeling suggests that as precipitation becomes the dominant source of new water to the aquifer, groundwater quality may improve dramatically.
Page 4.1-135 A key assumption is that the addition of limestone would be effective in maintaining a relatively high pH of 8 in order to limit metal solubility. This can be done, but close monitoring of the pH and water quality of collected leachate from these stockpiles is recommended to ensure the effectiveness of the lime treatment (see Section 4.1.3.5 for a discussion of recommended monitoring measures).56 56 Tribal cooperating agencies disagree with this approach. The tribal cooperators take the position that the effectiveness of lime treatment is very important in the final water quality of mine effluent. Therefore, this analysis should be conducted prior to the constriction of the facility and the results included in the DEIS.
Several of these stockpiles would then be converted to store Category 1 waste rock from the West Pit (reference); care would be taken to ensure that the liner system would not be damaged during the conversion and remain functional, but only a vegetated soil layer would be installed.57 57 The tribal cooperators take the position that the effectiveness of the evapotranspiration caps (i.e., vegetated soil layer) has not been demonstrated. Tribal cooperating agencies have requested that this analysis be done (GLIFWC Comment letter of June 30, 2008 and GLIFWC comment letter of February 6, 2009).
Most of the treated water would be returned to the East Pit, but a portion would be discharged through a wetland treatment system into the West Pit.58 58 As previously discussed, the tribal cooperating agencies’ position is that the effectiveness fo the wetland treatment system is in doubt.
The Mine Site Alternative would not affect the size or depth of the mine pits, so its effects on groundwater levels at the Mine Site and in the area surrounding the Mine Site are expected to be approximately the same as for the Proposed Action.59 59 It is the tribal cooperating agencies’ position that the effects on groundwater levels at the mine site are unknown for both the proposed project and the mine site alternative because of insufficient analysis.
Page 4.1-142 Both the Proposed Action and the Mine Site Alternative would comply with all surface water quality standards along the Partridge River. As Table 4.1-74 indicates, the Mine Site Alternative would result in improved water quality for most parameters, although chloride, lead, selenium, sulfate, and zinc concentrations are predicted to be marginally lower under the Proposed Action.60 60 Tribal cooperating agencies note that wild rice grows on the lower Partridge River. Therefore, it is the tribal cooperating agencies’ position that the wild rice sulfate standard applies and the mine site alternative effluent would exceed that standard (Table 4.1-74).
Page 4.1-144 Section 4.1.3.5 discusses potential mitigation measures that address the potential for exceedances of surface water standards in the West Pit overflow.61 61 As discussed for the proposed action, tribal cooperators disagree with this approach. It is the tribal cooperating agencies’ position that all waters of the state are protected by surface water quality standards and using the unnamed water to dilute the contaminants of the West pit is not appropriate. Furthermore, tribal cooperators note that the pit lake is predicted to not meet surface water quality standards for hundreds or thousands of years.
Page 4.1-146 Nevertheless, there remains some uncertainty as to whether the West Pit overflow would meet the Great Lakes Initiative standard for mercury and additional analysis of this issue is recommended.62 62 As previously discussed, it is the tribal cooperating agencies’ position that this analysis must be included in the DEIS.
Table 4.1-77 Reduce average flow by approximately 1.5 cfs. Minimal reduction in annual 7-day low (~0.1 cfs). No significant effect on river morphology or 100-year floodplain.63 63 Tribal cooperating agencies take the position that there is insufficient data to support this claim.
All parameters predicted to meet surface water quality standards during all flow conditions for all mine years. West Pit overflow in Closure predicted to initially exceed standards for several parameters, but water quality is expected to improve over time and exceedances could be mitigated.64 64 Tribal cooperating agencies take the position that the west pit is predicted to exceed standards for all years for which predictions were made.
4.1.3.4 Tailings Basin Alternative
Page 4.1-147 All parameters predicted to meet surface water quality standards during all flow conditions for all mine years.65 65 Tribal cooperating agencies take the position that the wild rice standard for sulfate would be exceeded.
Page 4.1-148 In general, the preference would be to maximize the amount of water recycled to the Tailings Basin (in order to minimize hydrologic impacts to the Partridge River from water withdrawals from Colby Lake), as long as it would not result in exceedances of groundwater or surface water quality standards or become unsuitable for use as make up water at the Processing Plant.66 66 It is the tribal cooperating agencies’ position that an untreated discharge of tailings basin water to the Partridge River will exceed water quality standards. In particular the wild rice standard will be exceeded.
A permeable reactive barrier (PRB) would be installed to provide final treatment of the groundwater seepage, if needed, to meet groundwater evaluation criteria, assuming testing during operations demonstrates it to be effective.67 67 Tribal cooperating agencies note that pumping could be needed for hundreds or thousands of years if the PRB is not effective. The PRB is untested and has not been demonstrated to work in any similar situations. In addition, the PRB would need periodic recharging/replacement which would need to occur at regular intervals for as long as water treatment is needed (hundreds or thousands of years). It is the tribal cooperating agencies’ position that this long term maintenance is at odds with Minnesota’s goal of maintenance free closure.
Page 4.1-153 This discharge, which varies in volume and slightly in quality between the No Recycle and Maximum Recycle options, would affect flows and water quality in the Lower Partridge River, but would have no effect on flows or water quality in the Upper Partridge River.68 68 Tribal cooperating agencies take the position that discharging untreated tailings basin water to the Partridge River will have significant adverse impacts.
Page 4.1-155 These data indicate that the only parameter predicted to exceed surface water standards would be thallium.69 69 Tribal cooperating agencies note that wild rice grows on the lower Partridge River. Therefore, it is the tribal cooperating agencies’ position that the 10 mg/l standard for sulfate applies. This standard would be exceeded by the PolyMet discharge. Furthermore, there are other projects (Mesabi Nugget Phase II and Laskin Energy) that are discharging water with elevated constituents. Given these existing sources, it is unlikely that PolyMet discharge would be able to discharge their untreated tailings basin effluent without violating the clean water act.
The surface water standard of 125 μg/L, however, represents dissolved aluminum concentrations, while the predicted concentration represents total aluminum concentrations.70 70 It is the tribal cooperating agencies’ position that the predicted concentrations in TB-15 represent dissolved aluminum (see TB-15, page 1). TB-15 presents the most recent water quality predictions for the Tailings Basin Proposes Action and Alternatives. TB-15 predicts exceedance of standards by dissolved aluminum under the Proposed Action and the Alternatives.
Therefore, the Tailings Basin Alternative is not predicted to result in the exceedance of any surface water quality standards in the Lower Partridge River.71 71 As previously discussed, tribal cooperating agencies disagree. It is the tribal cooperating agencies’ position that aluminum exceeds standards under the Proposed Action and the Alternative.
Page 4.1-157 For both options, all parameters are expected to meet surface water standards during all flow conditions for all modeled years.72 72 Tribal cooperating agencies note that this is not correct. It is the tribal cooperating agencies’ position that the wild rice sulfate standard applies (10 mg/l) and would be exceeded.
Page 4.1-158 As discussed above, the surface water standard of 125 μg/L represents dissolved aluminum, while the predicted concentration represents total aluminum.73 73 It is the tribal cooperating agencies’ position that the results in TB-15 represent dissolved aluminum. TB-15 predicts exceedance of the aluminum standard.
Page 4.1-159 Under low flow conditions, the sulfate loading would still be reduced, but this effect would be offset by reduced flows in the Embarrass River from the seepage capture resulting in slightly higher sulfate concentrations (Barr 2009, Additional information in support of NorthMet DEIS Critical Path Requires Actions).74 74 The tribal cooperating agency position is clear. The wild rice standard applies and must be enforced.
Page 4.1-162 The discharge of captured seepage to the Partridge River is predicted to meet surface water standards.75 75 Tribal cooperating agencies note that wild rice grows on the lower Partridge River. Therefore, it is the tribal cooperating agencies’ position that the wild rice sulfate standard applies and would be exceeded by the proposed PolyMet discharge.
Table 4.1-88 Discharge of between 1.1 cfs (Maximum Recycle Option) and 5.2 cfs (No Recycle Option) of groundwater seepage pumped from vertical wells to the Lower Partridge River would meet all surface water quality standards during all flow conditions for all mine years, although it would significantly increase sulfate loadings and reduce the available assimilative capacity.76 76 Tribal cooperating agencies note that wild rice occurs on the lower Partridge River. Therefore, Tribal cooperating agencies take the position that the wild rice sulfate standard applies and would be exceeded.
4.1.3.5 Mitigation and Monitoring Measures
Page 4.1-163 Groundwater seepage from the Tailings Basin is predicted to meet all groundwater evaluation criteria with the possible exception of aluminum. Aluminum is a USEPA secondary MCL standard for managing aesthetic consideration and not to protect human health, and is naturally found in elevated concentrations in the Project area.77 77 As stated in TB-14 “Manganese: The concentration of manganese in groundwater is predicted to be above the groundwater standard and the MCL at all four of the evaluation locations.”
All parameters predicted to meet all surface water quality standards in the Embarrass River under all flow conditions for all mine years.78 78 Tribal cooperating agencies disagree. The wild rice sulfate standard applies and will be exceeded. TB-15 predicts that dissolved aluminum would exceed surface water standards.
Page 4.1-164 Potential mitigation measures at the Mine Site, Plant Site, and Tailings Basin are discussed below.79 79 It is the tribal cooperating agencies’ position that treatment of the tailings basin effluent that is captured by the vertical wells must be an integral part of the tailings basin alternative. This treatment could occur in the WWTF already proposed for this project or in a second facility closer to the discharge point. However, treatment of the tailings basin effluent prior to discharge to the Partridge River is not included in the potential mitigation measures listed below. Tribal cooperating agencies strongly oppose an untreated discharge of tailings basin water to the Partridge River. In addition, there are other existing facilities and mine proposals (Laskin Energy, Mesabi Nugget Phase II) that discharge, or are proposing to discharge water at this same location. Finally, water quality of the discharge would exceed the wild rice sulfate standard that applies to the lower Partridge River.
4.1.4.2 Water Quality Page 4.1-187 The NorthMet Project is expected to meet all surface water quality standards under all flow conditions for all mine years in the Partridge River.80 80 Tribal cooperating agencies disagree. Wild rice grows on the lower Partridge River and it is the tribal cooperating agencies’ position that the wild rice sulfate standard applies. The PolyMet discharge under the tailings basin alternative would not meet this standard.
Page 4.1-187/8 According to available surface water monitoring data, including sulfate sampling conducted as part of the recent wild rice field survey (Barr, Draft 2009 Wild Rice and Sulfate Monitoring), sulfate concentrations in the Upper Partridge River (average of 5 to 6 mg/L during the wild rice survey and an average of 6 to 10 mg/L during historic monitoring) are generally consistent with the baseline conditions found in the South Branch of the Partridge River in the 1970s (5.2 mg/L), despite periodic Peter Mitchell Pit dewatering discharges that average about 57 mg/L.81 81 It is the tribal cooperating agencies’ position that the wild rice standard for sulfate applies on the Lower Partridge River.
Page 4.1-191 Overall, water quality in the Embarrass River meets all surface water standards with the exception of mercury.82 82 The position of tribal cooperating agencies is that the wild rice standard for sulfate applies.
Page 4.1-192 Both Tailings Basin Alternative options would reduce average sulfate loading below existing conditions (Table 4.1-85). 83 83 Tribal cooperating agencies note that the Army Corps has not completed its consultation with the potentially affected tribes. In addition, a survey for wild rice presence in the waters potentially affected by the proposed mine has only recently begun. Tribal staff have already found extensive stands in the Lower Partridge River. Tribal cooperating agencies believe that the consultation process and wild rice surveys should be completed and the results included in the DEIS. This data can then be used to evaluate the cumulative impact analysis to this important tribal resource.
4.2 WETLANDS 4.2.1 Existing Conditions 4.2.1.1 Introduction Wetlands in Minnesota are protected under federal and state laws, including the Federal Clean Water Act (CWA) Section 404 permits and Section 401 certificates, the State of Minnesota’s Wetland Conservation Act (WCA), the MnDNR’s Public Waters Work Permit Program, and MPCA’s Wetland Standards and Mitigation Rules (Minnesota Rules, part 7050.0186).
Although permits are required from both the state and federal agencies, the permitting processes differ in the definition of wetlands/waters that are regulated in each process. Under the WCA regulations, “isolated” wetlands are regulated, but not “incidental” wetlands (i.e., a wetland created solely by actions not meant to create the wetland). Conversely, under the federal Section 404 regulations, “isolated” waters, including wetlands, are not regulated, but “incidental” wetlands may be. All of the wetlands on the Project site would be regulated through either the CWA or the WCA.
The required public notice for the Section 404 permit was issued by the USACE in May of 2005. The CWA requires any state to act on requests for Section 401 water quality certification within one year of the request; otherwise, the applicable CWA Section 401 requirements are waived. The MPCA did not act on the Section 401 request during the one year timeline, therefore, the 401 certification was waived, by default, in May of 2006. Waiver of the certification by MPCA does not affect the applicability of Minnesota Water Quality Standards to the Project.1
1 It is the tribal cooperating agencies’ position that the public notice for the Section 404 permit should be reissued and that the Minnesota Pollution Control Agency should be afforded the opportunity to analyze and make a determination under Section 401 of the Clean Water Act. Significant changes in the design of the Proposed Action have occurred, and other important information needed to determine the nature and magnitude of the Project’s impacts has been developed since the public notice was provided by the USACE in May of 2005. Adverse water quality impacts and exceedances of groundwater quality standards are predicted as a result of the proposed Project. Additionally, the Project would lead to significant degradation of aquatic resources, including water quality standard violations in both the Partridge and Embarrass rivers (see Table 4.1-68 for a summary of water quality impacts). MPCA should be afforded the opportunity to certify or deny certification of the Proposed Action.
4.2.1.2 Wetland Delineation Existing wetland resources were evaluated within the approximately 3,016-acre Mine Site as well as an additional 1,000 acres at the Plant Site and along the railroad and treated water pipeline corridors. Potential wetland locations were determined through non-field analyses that included review of historic aerial photographs; USGS quadrangle maps; two-foot contoured topographical data; National Wetlands Inventory (NWI) maps; MnDNR color aerial infrared photography; and, where available, soils and hydrology information.2 Final wetland locations were field delineated and characterized from 2004 to 2008 (Figures 4.2-1 through Figure 4.2-4).3
2 It is the position of the tribal cooperating agencies that it is not possible to differentiate between rich forested peatlands, poor fens, and bogs using canopy cover alone. Identification of the low shrub, forb and graminoid layers are required. 3 It is the position of the tribal cooperating agencies that the current wetland delineation does not encompass all wetlands that may be affected by the Project. Because no initial determination of the Project’s area of influence (AOI) on wetlands was made, the site field surveys of wetland and other vegetation were limited to little more than the area within the Project fence. The existing characterization of wetland and other vegetation does not cover even one-half the area that might reasonably be expected to be impacted by disruption of the existing hydrology. Around the tailings basin virtually no wetland delineation has taken place although wetland impacts from inundation are likely to occur. The Army Corps is developing a workplan to assess impacts to these additional wetlands but this workplan has not been finalized or implemented. Given the importance of this work in assessing potentially significant impacts to wetlands, it is the position of the tribal cooperating agencies that this work should be included in the DEIS to allow for a full public review. Hydrology and Wetland Vegetation The hydrology of the wetlands at the Mine Site has been stable over time. Factors contributing to this stability include: 1) the lack of continuity between the bedrock and surficial aquifers within the perched wetlands; 2) slow water movement through soils; 3) a slow lateral flow component that helps sustain down gradient wetlands with a continual supply of groundwater over time; 4) recharge from surrounding uplands; 5) relatively flat topography across most of the site; and 6) the high water-holding capacity of the soils (Barr 2008, Memorandum: Indirect Wetland Impacts at the Mine Site). Wetland hydrology at the Plant Site has been affected by the operation of the LTVSMC Tailings Basin. Evidence suggests that hydrologic changes from Tailings Basin seepage, along with beaver dams, have resulted in inundation of wetland areas immediately north of the Tailings Basin (Barr 2008; Lined Tailings Basin Alternative – EIS Data Request).4
4 Tribal cooperating agencies strongly object to the characterization of the hydrology at the mine site presented in the previous paragraph. It is the Tribal cooperating agencies’ position that the methodology used in the Adams 2009 email is not adequate for characterization of pit dewatering impacts to wetlands (GLIFWC 2009, Memorandum to Jon Ahlness and Stuart Arkley: Photographic evidence for pit impacts to wetland hydrology. April 24, 2009). Problems with the methodology used in the email include: 1. Lack of recognition that aerial photos are a very imprecise measure of surface water level. 2. Photographs presented in the paper show that the Peter Mitchell pits are mostly flooded. Therefore there is little or no stress on surrounding wetlands at the time. 3. Lack of consideration of the topographic relationship of the landscape features including the depth of the Peter Mitchell Pits (P-M Pits approximately 80 feet deep, PolyMet pits approximately 800 feet deep). 4. Lack of recognition that some changes in groundwater hydrology would not be evidenced by the large changes in surface water level that could be detected by aerial photography. 5. Dependence on wetland soil conductivity values that are extremely low and for which supporting source citation in the professional literature cannot be found. The PDEIS appears to rely on “best professional judgment” for estimating impacts due to hydrologic disruption without incorporating specific knowledge of the ecological requirements of culturally significant wetland vegetation such as cedar, and without requiring sufficient background data regarding groundwater. A “best professional judgment” approach is being used as a replacement for data-based scientific analysis of potential impacts. Quantitative methods for estimating the impacts of drawdown and inundation on wetland hydrology exist, have been used at other mine sites, and can be used in addition to professional judgment.
The soils and hydrology at the Mine Site support a stable wetland systems comprised in large part by bog communities represented by open and coniferous bogs, as well as shrub carr/alder thicket dominated by alder and willows, and forested swamp communities comprised of hardwood and coniferous trees.5 Most of the wetland vegetation present at the Mine Site (72 percent) is indicative of acid peatland systems (e.g., open and coniferous bogs) that are dependent on precipitation rather than groundwater for hydrologic inputs and reflect a perched water table. There are other wetland communities present at the Mine Site, such as shrub swamps (12 percent), forested swamps (9 percent), and wet/sedge meadows (4 percent) that may receive some portion of its hydrology from groundwater. The remaining shallow marsh community (3 percent) generally results from artificial impoundment by beaver dams, roads, and railroads and is primarily dependent on surface waters for hydrology.
5 Tribal cooperating agencies take the position that subsurface flow through upland soils likely provides the micro nutrients necessary for rich forested peatlands, cedar swamps and poor fens found in the mine site area. Many of the wetlands that have been identified during delineation as "perched bogs" are actually cedar swamps, northern wet ash swamps, forested rich peatlands, northern alder swamps, and poor fens, all of which require groundwater inputs. Indirect impacts to communities that require groundwater inflow have not been determined, but would likely be significantly different than expected impacts from the Project to perched bogs
Mine Site The wetland delineation identified 1,302 acres of wetlands within the Mine Site (Figure 4.2-1), including approximately: • Coniferous bog and open bog communities – 938 acres; • Shrub carr/alder thicket wetland communities – 155 acres; • Forested swamp (hardwood and coniferous) communities – 120 acres; • Wet/sedge meadow communities – 49 acres; and • Shallow marshes – 39 acres.
A bog is a peatland that is nutrient poor because it lacks access to substantial quantities of mineral-rich ground waters (Brinson 1993). Shrub carr and alder thickets are wetlands in which the uppermost stratum of vegetation is comprised primarily or shrubs.6 Swamps are emergent wetlands in which the uppermost stratum of vegetation is comprised primarily of trees. Sedge meadows are wetlands dominated by plants in the Cyperaceae family.7 Marshes are wetlands with emergent, herbaceous vegetation that includes sedges and other emergent plants, but is not dominated by plants in the Cyperaceae.8
6 Tribal cooperating agencies take the position that northern alder swamps (FPn73) "occur in settings that receive mineral rich surface or subsurface flow, which is maintains surface water with nearly neutral pH." (MN DNR Field Guide to the Native Plant Communities of Minnesota, the Laurentian Mixed Forest Province, pg 205.) 7 Tribal cooperating agencies take the position that "Surface water in Northern Wet Meadow/Carrs is derived from runoff, stream flow, and groundwater sources, it has a circumneutral pH (6.0 - 8.0) and high mineral and nutrient content. " (MN DNR Field Guide to the Native Plant Communities of Minnesota, the Laurentian Mixed Forest Province, pg 292.) 8 Tribal cooperating agencies take the position that Northern mixed cattail marshes "develop in areas occupied by fens or wet meadows following fires-usually during severe droughts-that remove accumulated peat from the fen or meadow". (MN DNR Field Guide to the Native Plant Communities of Minnesota, the Laurentian Mixed Forest Province, pg 298.)
The coniferous bog and open bog communities make up the majority of the wetlands at the Mine Site. Black spruce, tamarack, and balsam fir are the dominant canopy tree conifers. White cedar and deciduous swamp birch are also occasionally found in this community.9 Shrubs are usually ericaceous (belonging to the heath family) and/or speckled alder and raspberry. Sphagnum moss comprises an almost continuous mat with interspersed, non-dominant forbs such as bunchberry and blue bead lily along with sedges and grasses.10 Hydrologically, this complex is characterized by a relatively stable water table (RS44, Barr 2006).11 All but one (wetland ID 27, Table 4.2-3) of the coniferous bog community wetlands identified at the Mine Site are rated as high quality in accordance with the Minnesota Routine Assessment Method for Evaluating Wetland Functions. Wetland 27 has some fill and therefore was rated as moderate quality.12
9 Tribal cooperating agencies take the position that this canopy cover depicts a northern rich spruce swamp (FPn62) which requires groundwater. Balsam fir and white cedar are both rich forest indicator species. 10 Tribal cooperating agencies take the position that bunchberry and blue bead lily are both indicator species in the forb layer of mineral rich peatlands (MN DNR Field Guide to the Native Plant Communities of Minnesota, the Laurentian Mixed Forest Province, pg 317). 11 Tribal cooperating agencies take the position that a stable water table in NE MN is typically the result of groundwater inputs in periods of low precipitation. 12 Tribal cooperating agencies take the position that the canopy cover and herbaceous layer noted above indicate significant groundwater inputs to the wetland communities.
Plant Site The existing Tailings Basin is an actively permitted waste storage facility and is therefore not subject to state and federal wetland regulations. Existing wetland resources mapped around the Tailings Basin are shown in Figure 4.2-2 and consist largely of deep marsh with dead black spruce trees scattered throughout, which is primarily attributable to seepage from the basin (Barr 2008, Memorandum: Wetland Impacts – Tailings Basin Mitigation Alternative, May 28, 2008). Other smaller wetland areas are comprised of shallow marsh, wet meadow, shrub carr, coniferous swamp, and open water. The existing wetlands differ from the wetlands that occupied the area prior to the construction of the Tailings Basin. Historical aerial photographs (1940 and 1948) indicate the presence of large wetland complexes that were a mixture of forested and shrub/scrub wetlands, which were primarily saturated to the surface with minimal open water areas. Past disturbances that have affected the hydrology and vegetative characteristics of the wetlands in the vicinity of the Tailings Basin include seepage from the Tailings Basin along with beaver dams, culverts, road construction, parking areas, railroad embankments, and diversion of flowages (Barr 2008, Memorandum: Wetland Impacts – Tailings Basin Mitigation Alternative, Revised June 2, 2008).13
13 Tribal cooperating agencies take the position that the approximately 5,700 (RS13B) gallons per minute of tailings water released by past mine waste disposal activity has likely had a far greater influence on the hydrology of the area than beaver dams or transportation features.
4.2.3 Environmental Consequences 4.2.3.1 Proposed Action
Potential Direct Wetland Impacts The direct wetland impacts estimated for the Proposed Action would be the result of excavation, filling, or other activities that would result in wetland loss and loss of wetland functions and values. Total estimated direct wetland impacts for the Proposed Action are estimated at 854.2 acres. Direct impacts to specific Project areas are described in Table 4.2-3. Mine Site Direct Wetland Impacts A total of 76 wetlands are located within the Mine Site comprising 1,302 total acres. Of these, 55 wetlands, totaling 804.3 acres, would be directly impacted. The locations of the wetlands impacted at the Mine Site are shown in Figure 4.2-5. Table 4.2-3 lists the impacted Mine Site wetlands and their community types. The impacted wetlands would include a number of different types. The most common wetland types are coniferous bog (510 acres) and open bog communities (76 acres). These two communities comprise 73% of the direct wetland impacts at the Mine Site (Table 4.2-4).14
14 Tribal cooperating agencies disagree. The wetland delineation study (RS14, Appendix A) identified over 390 acres of wetland community with a significant white cedar component. For example, wetland ID-48 (Table 4.2-3) was identified in delineation reports as dominated by white cedar. White cedar is an indicator of mineral rich waters. Renaming wetland ID-48 as a coniferous bog, as was done in Table 4.2-3, does not make that community a bog. Cedar dominated wetlands are cedar swamps, not bogs. The significance of this is that, bogs tend to be precipitation fed while swamps tend to be groundwater fed. Data from the wetland delineations (RS14) suggest that bogs are not the most prevalent wetland type. In fact, it appears that wetlands that require groundwater inputs: forested rich peatlands and poor fens are the most prevalent.
At Post-Closure (approximately Year 65), the West Pit would overflow and discharge water into wetland number 32 (Figures 4.1-22, 4.2-1, and 4.2-5), and then through a stream channel to the Partridge River. Wetland number 32 and the downstream channel would be modified to accommodate the predicted flow of 2.6 cfs. The direct impacts to wetland number 32 are included in the wetland impact direct totals (Table 4.2-3).15
15 It is the position of the tribal cooperating agencies that because a stream channel can be seen in aerial photographs, the discharge would follow a stream channel through the aforementioned wetlands.
Potential Indirect Wetland Impacts The determination of indirect wetland impacts from the Proposed Action took into consideration the following conditions: • Changes in surface water or groundwater flow rates and patterns, which could affect wetland hydrology and result in the diminution of wetland functions and/or changes in wetland cover types; • Changes in surface or groundwater quality, which could result in the diminution of wetland functions; and • Non-hydrologic changes, such as habitat fragmentation and the effects of fugitive dust, noise, and vehicular emissions, which could result in the diminution of wetland functions. For each area assessed for direct wetland impacts – Mine Site (including haul roads), Plant Site (including the Tailings Basin), and the transportation corridor (i.e., rail line, treated water pipeline, and Dunka Road) – the potential for indirect impacts to wetlands located in and around the impact area was assessed and summarized below.16
16 Tribal cooperators note that the work needed to properly assess indirect wetland impacts at the mine site and at the plant site has not been completed. It is the position of the tribal cooperating agencies that the wetlands work group should finalize the indirect wetland impact workplan and that the results of that investigation be included in the DEIS to allow a full public review.
Mine Site Indirect Wetland Impacts17 The Proposed Action would change the hydrology of the Mine Site through the establishment (and dewatering) of mine pits, waste rock stockpiles, and a dike and ditch system that minimizes lateral movement of surface water and shallow groundwater within surface deposits. This drainage system was designed to minimize the amount of surface water flowing onto the Mine Site; eliminate process wastewater and non-contact stormwater flowing uncontrolled off the Mine Site; and minimize the amount of stormwater flowing into the mine pits. Where dikes intersect wetlands, seepage control measures would be installed to restrict groundwater movement through higher permeability areas with the intention of helping to prevent drawdown of wetland water levels near mine pits and reduce inflows to the mine pits, although hydrologic impacts to wetlands from pit dewatering are not expected to be significant, as discussed below
17 Tribal cooperating agencies note that there is no reliable groundwater model for groundwater drawdown impacts of the proposed project. The estimates of groundwater drawdown are currently based on anecdotal observations and analysis of historical aerial photography. Therefore, there is no quantitative assessment of mine related drawdown of the regional water table. This serious data gap has prevented an adequate indirect impact assessment for wetlands from being conducted.
To analyze potential hydrologic changes and related effects on surface water wetlands, the Mine Site and surrounding lands were divided into 24 contributing watershed areas, or tributary areas, representing the existing, relatively undisturbed conditions at the Mine Site (Figure 4.2-6). During mining and Post-Closure, this number would be reduced to 22 watershed areas (Figure 4.2-7), and the size of the watersheds would change (Barr 2008, Memorandum: Indirect Wetland Impacts at the Mine Site). Wetlands within the interior of the Mine Site that are surrounded by or within 50 feet of haul roads, portions of the ditch and dike system, mine pits, and waste rock stockpiles would incur indirect impacts. These activities would affect wetlands by changing its hydrology, which could result in changes in wetland type, and by reducing its wildlife habitat functions and values as a result of habitat fragmentation and exposure to dust, vehicular emissions, noise, and human activity. These indirect wetland impacts at the Mine Site would total approximately 318.6 acres.
Wetlands at the Mine Site are believed to be primarily bogs, which are supported by direct precipitation with some variable surficial groundwater component from adjoining uplands.18 Of wetland communities present at the Mine Site that could be at least partially dependent on groundwater for hydrology (i.e., wet meadow, sedge meadow, alder thicket, shrub carr, coniferous swamp, and hardwood swamp) only 83.3 acres are not already predicted to be either directly or indirectly impacted by the Proposed Action. This represents the upper bound of potential additional indirect wetland impacts on the Mine Site. Based on landscape position, at least 65 percent of this 83.3 acres appear to be at least partially supported by surface water (Wetlands 12, 53, and 58). These wetlands are not expected to be indirectly impacted and are not included in the 318 acres of indirect wetlands identified above.
18 As previously discussed, tribal cooperating agencies have reviewed the information in the Adams 2009 email and have concluded that the methods used are not sufficient for prediction of pit dewatering impacts to wetlands. Tribal cooperating agencies fail to see how the aerial photographs presented in the email substantiate the assumption that wetlands are not connected to groundwater particularly with regards to the Peter Mitchell Pit. Additional detail on this topic is available is section 4.1. In addition, based on the vegetation data collected from wetland delineations it appears that groundwater supported wetlands are common in the Project area. Indirect impacts to communities that require groundwater inflow have not been determined, but would likely be significantly different than expected impacts from the Project to perched bogs.
Since PolyMet proposes to capture and treat all process water (i.e., any water touching disturbed ground), no indirect wetland impacts are expected related to surface water quality. In terms of groundwater quality, groundwater within the surficial aquifer at the Mine Site was generally found to meet groundwater evaluation criteria except for elevated concentrations of aluminum, iron, and manganese, which are assumed to be naturally occurring (see Section 4.1.1.2). Groundwater quality modeling predicts that the Proposed Action would result in exceedances of the antimony, manganese, nickel, and sulfate groundwater evaluation criteria in various locations and for various durations, some for very long periods (i.e., over 2,000 years). The groundwater evaluation criteria, however, are based on the actual or potential use of groundwater as a source of drinking water. Generally the Class 2B surface water standards (see Table 4.1-20) are used to protect wetlands (Minnesota Rules parts 7050.0186 and 7050.0222) as these standards were developed to maintain healthy aquatic and wetland communities. Predicted nickel concentrations in groundwater from the Category 3 Lean Ore and Category 3 Waste Rock stockpiles and possible antimony in groundwater from the Category 3 Waste Rock Stockpile would exceed the wetland standards. As discussed previously, however, most of the wetlands at the Mine Site are bogs that are believed to be hydrologically supported by perched water tables with little interaction with the underlying groundwater. Affected leachate from the Category 3 Lean Ore and Category 3 Waste Rock stockpiles would flow toward the Partridge River with no intervening wetlands that are groundwater dependent. Therefore, no indirect wetland impacts are anticipated at the Mine Site resulting from groundwater quality.19
19 Tribal cooperating agencies strongly disagree with this conclusion. As previously indicated, there is no data based evidence or analysis on which to conclude that wetlands would not be affected by mine related water quality changes. Existing exceedances do not predict plant community changes that may occur due to additional disturbance. The Project’s discharges to groundwater and surface water will have to comply with Minnesota water quality standards.
In summary, based on these potential changes to wildlife habitat and site hydrology, it is estimated that a total of 318.6 acres of wetlands are likely to be indirectly impacted by the Proposed Action, resulting in changes in wetland type, function, and/or value (Table 4.2-3 and Figure 4.2-5). The appropriate mitigation ratios and acceptable mitigation sites for the predicted indirect wetland impacts at the Mine Site would be determined by the USACE and the State during permitting.20
20 Tribal cooperating agencies take the position that indirect impact acreages would be greater if data and quantitative analysis of mine induced drawdown had been conducted. Additional detail on the inadequacies of the existing groundwater modeling are available in section 4.1.
In addition to these predicted indirect wetland impacts at the Mine Site, the potential exists for additional indirect wetland impacts in areas beyond the Mine Site. These potential impacts are primarily related to the potential for groundwater drawdown from mine pit dewatering to adversely affect wetland hydrology. Based on empirical observations at taconite surface mining operations in the region, including the nearby Peter Mitchell Mine, little indirect hydrologic impacts to nearby wetlands have been observed from mine dewatering (Adams and Liljegren 2009). Experience at other mining sites in the Iron Range further support this conclusion (AMEC 2007; Barr 2009, Northeastern Minnesota Wetland Mitigation Inventory).21
21 As previously discussed, tribal cooperating agencies have reviewed the information in the above referenced email (Adams 2009) and it is the Tribal cooperating agencies’ position that the methods used are insufficient for prediction of indirect impacts to wetlands. For example, the projects listed above are located in upland areas of the range and are not proper reference sites for potential impacts at the PolyMet mine site. The Peter Mitchell Mine, although in close proximity, is very shallow compared to the proposed mine pits (Peter Michell pit is approximately 80 feet deep, PolyMet pit is aproximately 800 feet deep).
For these reasons, additional indirect impacts to wetlands associated with groundwater drawdown from pit dewatering is anticipated to be minimal, with little to no dewatering of wetlands expected outside the Mine Site.22
22 Tribal cooperating agencies take the position that this conclusion is faulty. Based on the vegetation data collected from wetland delineations it appears that groundwater supported wetlands are common in the Project area. Indirect impacts to communities that require groundwater inflow have not been determined, but would likely be significantly different than the expected impacts from the Project to perched bogs.
Nevertheless, wetland monitoring would be required during Project operations and Closure over a larger area than the Mine Site (to be determined during permitting) to detect if any additional impacts occur. This monitoring would assess both wetland hydrology and vegetation. Compensatory wetland mitigation would be required for any indirect wetland impacts determined through this monitoring.23 . 23 Tribal cooperating agencies disagree with this approach. Monitoring would only identify impacts after they have become apparent in the wetland. Tribal cooperating agencies take the position that the DEIS should provide a detailed description of reasonably foreseeable impacts to wetlands so that decision makers and the public can have a complete picture of the environmental consequences of this project.
Transportation Corridor Indirect Wetland Impacts The only potential indirect impacts related to the treated water pipeline or the Dunka Road improvements would be associated with dust and vehicle emissions that may occur during facility construction and operations.
Along the rail line, it is likely that ore rock and fines could escape through gaps in the rail cars during transport from the Mine Site to the processing plant. This ore, when oxidized could result in the release of sulfate and various metals to streams and wetlands crossed by the rail corridor. It is difficult to estimate the extent of possible ore spillage, although, in terms of the total volume of waste rock and ore that would be handled at the Mine Site, it is not expected to be a large volume. PolyMet proposes loading procedures to minimize the potential for spillage and indicates that any large rock that may spill would be recovered during routine track maintenance. Mitigation and monitoring measures addressing ore spillage are discussed in Section 4.1.3.5. Overall, these indirect wetland impacts along the transportation corridor are considered minor and would not be expected to significantly affect wetland functions or result in changes to wetland cover types, therefore no indirect wetland impacts are predicted for the transportation corridor.24
24 Tribal cooperating agencies disagree with this conclusion. As indicated in Section 3.1.3, it is likely that ore dust would spill from rail cars and be deposited in wetlands adjacent to the rail line. No analysis of any type has been conducted to determine if such impacts would be significant.
Plant Site and Tailings Basin Indirect Wetland Impacts No wetlands are located within the Processing Plant area; therefore, no indirect wetland impacts would occur from its reuse. The Tailings Basin would be designed not to overtop, so there would be no surface discharges. It is expected that surface seepage would occur from the basin, but PolyMet proposes a surface seepage collection system that would capture essentially all of the surface seepage and return it to the Tailings Basin until the seeps dry out.25
25 Tribal cooperating agencies take the position, based on the existing available contaminant modeling, that seepage capture would be needed for hundreds or thousands of years to avoid water quality and quantity impacts to wetlands.
The final elevation of the pond in Cell 2E is approximately 1,722 feet mean sea level (MSL) (January 2007 PD), or approximately 222 feet above the local base elevation (approximately 1,500 feet MSL). The net difference in the height above grade for Cell 2E is approximately 3.3 percent greater than Cell 2W (215 feet above grade or 1,715 feet MSL). Based on the procedure described above, the northern extent of the seepage impacts from the toe of Cell 2E was estimated to be approximately 0.78 mile, or 3.3 percent further than the northern extent of the impacts from Cell 2W (0.75 mile). The lateral (east and west) extent of the estimated impacts was estimated using the evaluation area boundary identified by Barr Engineering in the technical memo Lined Tailings Basin Alternative – EIS Data Request (Barr 2008, Lined Tailings Basin Alternative - EIS Data Request).26
26 Tribal cooperating agencies take the position that the method presented above is inadequate to assess indirect wetland impacts. This method ignores the fact that there is an area of uplands north of cell 2W which has constrained the movement and direction of tailings basin seepage. Therefore, using the northern extent of wetland impacts of 2W for 2E, north of which there are no uplands, is unjustified. Ignoring the presence of the upland area north of cell 2W creates an underestimation in the extent of wetland impacts due to seepage
The indirect wetland impacts were determined using mapped wetlands overlaid on a 2003 aerial photograph.27 There are approximately 547 acres of mapped wetlands within the evaluation area; however, some of the historic impacts from Cell 2W (approximately 197 acres) extended into the Cell 2E evaluation area. The remaining 350 acres of mapped wetlands do not appear to have been affected by the LTVSMC Tailings Basin operations. Based on the assumptions described above, all of the remaining 349.3 acres of mapped wetlands within the evaluation area are anticipated to be indirectly impacted by seepage from the NorthMet Tailings Basin.
27 Tribal cooperating agencies have suggested a more conventional method for indirect wetland impact estimation to the lead agencies (Methods for evaluating indirect hydrologic impacts to wetlands, March 26, 2009). This method could be applied at both the mine site and the plant site. The method proposed by tribal cooperating agencies was developed by a consultant for the Army Corps for use in another sulfide mine project EIS (Crandon Mine Project Environmental Impact Statement: Wetlands Technical Memorandum, 2003). In addition to having been developed by the Army Corps, this method has been presented by tribal technical staff at professional conferences (Society of Wetland Scientists Conference, 2009 and 55th Annual Meeting of the Institute of Lake Superior Geology, 2009). Tribal cooperating agencies do not agree that the unconventional method described above can produce defensible results for indirect hydrologic impacts to wetlands. A more robust method should be used and the analysis presented in the DEIS so the public can review a science-based assessment of potential impacts.
Groundwater quality monitoring at several wells completed in the surficial aquifer at or near the toe of the Tailings Basin found elevated concentrations for fluoride, molybdenum, sulfate, and total dissolved solids relative to the baseline well (GW-002, see Table 4.1-6). Based on these results, it was concluded that groundwater immediately downgradient of the Tailings Basin has been degraded by seepage from the basin, but there does not appear to be an overall trend, either increasing or decreasing, in the concentrations monitored. The areal extent of this impact is unknown due to the lack of a monitoring well network, but based on the limited data available, no offsite contamination has been documented and the water quality of nearby wells are consistent with baseline conditions in the region (Siegel and Ericson 1980; MPCA 1999).28
28 Tribal cooperating agencies note that there is a serious inconsistency between this section and information presented in Section 4.1.3.1 of this document. Section 4.1.3.1 states: “Therefore, future impacts to the hydrology of the aquifer and wetlands downgradient of the Tailings Basin were estimated by comparing predicted seepage rates for the Proposed Action (Hinck 2009) with the estimated groundwater flux capacity of the aquifer (155 gpm)(Technical Memorandum: TB-2 and TB-14: Tailings Basin Seepage Groundwater Quality Impacts Modeling Methodology). The current seepage rate toward the Embarrass River from the Tailings Basin (Cells 1E/2E and 2W) is estimated at 1,795 gpm, which continues to result in the upwelling of seepage water into the wetlands as the seepage rate exceeds the aquifer flux capacity by over 1,600 gpm. Under the Proposed Action, the unrecovered seepage rate is predicted to increase to a maximum of approximately 3,800 gpm in Year 20, over 2,900 gpm of which would be attributable to PolyMet (Hinck 2009). Therefore, under the Proposed Action, a significant increase (>100%) in groundwater upwelling relative to existing conditions would be expected. Some of this seepage water would drain to existing streams, but because of the generally flat topography and extensive wetlands, much of this water would be expected to form ponds and inundate wetlands.” Tribal cooperating agencies take the position that the latest relevant information developed for the water resources section has not been incorporated into the wetland impact section. The presentation of two different methods is confusing and does not provide an adequate assessment of wetland impacts. A thorough hydrologic impact analysis that incorporates actual seepage rates from the tailings facility should be conducted. In addition, these seepage rates should be used, in conjunction with tailings basin water chemistry information, to assess the effects of this untreated discharge to the biota and functional values of the Embarrass River watershed wetlands.
The results of transient flow modeling, which was used to predict groundwater quality downgradient from the Tailings Basin, indicate that only aluminum (maximum of 77 μg/L) would exceed the groundwater evaluation criteria of 50 to 200 μg/L (see Table 4.1-53). The predicted concentration of manganese would also exceed the secondary MCL (i.e., predicted maximum concentration of 193 μg/L versus an USEPA secondary MCL of 50 μg/L), but as indicated in Section 4.1.2.2, manganese concentrations below the state health-based HRL of 300 μg/L are not considered exceedances of groundwater evaluation criteria for purposes of this DEIS because baseline concentrations in local groundwater already exceed this standard.29 As discussed at the Mine Site, the groundwater evaluation criteria used in Section 4.1 were developed to be protective of human health. Using the wetland water quality standards (Minnesota Rules parts 7050.0186 and 7050.0222, basically the Class 2B standards from Table 4.1-20), the results of the Tailings Basin modeling indicate that groundwater would meet all wetland water quality standards. Therefore, indirect wetland impacts from changes in groundwater quality are not expected.
29 Tribal cooperating agencies disagree with the logic of the previous paragraph. Should it receive permits for its project, PolyMet will assume responsibility for all legacy contamination caused by the tailings basin to surface water, groundwater and wetlands. Therefore, tribal cooperating agencies take the position that the current exceedances, which are the result of decades of untreated discharges from the tailings basin, must be addressed by PolyMet as part of its closure plan.
Summary of Direct and Indirect Wetland Impacts The Proposed Action would have approximately 854.2 acres of direct wetland impacts (804.3 acres at the Mine Site, 10.5 acres along the transportation corridor, and 39.4 acres at the Tailings Basin) and 667.9 acres of indirect wetland impacts (318.6 acres at the Mine Site, none along the transportation corridor, and 349.3 acres at the Tailings Basin) for a total predicted impact of 1,522.1 acres.30
30 As previously stated, tribal cooperating agencies disagree with these conclusions and take the position that that acreage totals for indirect impacts are underestimated.
Of the 1,123 acres of impacted wetlands at the Mine Site and directly impacted wetlands at the Tailings Basin, bogs are the most prevalent impacted wetland type, with a total of 661 acres in coniferous bogs and 189 acres in open bogs (76 percent of total wetland impact).31
31 Tribal cooperating agencies take the position that data from the wetland delineations indicate that bogs are not the most prevalent wetland type. In fact, it appears that wetlands that require groundwater inputs: forested rich peatlands and poor fens are the most prevalent.
A total of 94 acres of impacts are predicted in alder thicket communities and 10 acres in shrub carr communities (together constituting 9 percent of impacts). Swamp impacts include 65 acres of coniferous swamp and 33 acres of hardwood swamp (8 percent of impacts). Remaining impacts include 29 acres of sedge meadow communities and 17 acres of wet meadow communities; deep marsh impacts of 28 acres and shallow marsh impacts of 41 acres; and 4 acres of shallow/open water wetland communities along with less than one acre of deepwater habitat. No direct or indirect wetland impacts to the 100 Mile Swamp have been predicted.32
. 32 Tribal cooperating agencies note that potentially impacted wetlands that are part of the 100 Mile Swamp were identified by the forest biologist in 1997 as “lacking ecosystem representation in protected areas.” (SNF 1997, January) Interest in protecting the unique character of these wetlands was based on their “watershed integrity, the presence of riverine ecosystems, and large amount of interior forest present.” This information was further substantiated in a report by the MNDNR titled “Evaluation of Selected Potential Candidate Research and Natural Resource Areas.” (SNF 1997, December) This document describes the 100 Mile Swamp wetlands as “these sites represent the highest quality remaining examples of characteristic ecosystems in each ecological Landtype Association on the Superior National Forest.” Tribal cooperating agencies take the position that this information must be included in the functional assessment for this project and included in the development of mitigation requirements for this project.
The quality of wetlands affected is a key factor in determining effects on wetland functional values. Section 4.2.1.4 and Table 4.2-3 provide an assessment of wetland functional values, including evaluation of applicable wetland functions and ratings of the vegetative diversity/integrity value based on MnRAM guidelines. Approximately 70 percent of the total wetlands to be affected, either directly or indirectly, are high quality wetlands with about 6 percent rated as moderate quality and the remaining 24 percent as low quality. Wetlands at the Mine Site typically have a high vegetative diversity/integrity score and a low disturbance score, representing high functions and values (MnRAM 3.0), while the wetlands at the Tailings Basin have generally been disturbed and are of lower quality. The potential exists for other, minor localized indirect wetland impact areas as a result of the Proposed Action.33 Wetland vegetation and hydrology monitoring would be conducted to determine if any additional indirect wetland impacts would occur, and additional compensatory wetland mitigation would be required for additional indirect wetland impacts.
33 It is the position of the tribal cooperators that the proposed action and the preferred alternative would likely not comply with the requirements of section 404(b)(1) guidelines, which do not allow a permit when there are practicable alternatives that would have less adverse effects, when the Project would lead to a violation of state water quality standards or when it would cause or contribute to significant degradation of waters of the United States. Other alternatives that were not considered in the DEIS (e.g. underground mining) would pose less harm to high quality wetlands, and may be less damaging to aquatic resources. As documented in Table 4.1- 68, the Project would result in water quality standards violations.
4.2.3.4 Tailings Basin Alternative The water discharge pipeline would be routed approximately 8.4 miles from the Tailings Basin southerly to a discharge point on the Partridge River (Feigum 2009). For 5.2 miles of its length, the pipeline would parallel and be constructed adjacent to the existing plant water supply pipeline from Colby Lake. The existing water supply pipeline was constructed above ground within a berm for reasons that are not entirely known, but believed to be attributable to bedrock outcrops and the need to insulate the pipe from freezing temperatures. For purposes of this DEIS, it is assumed that the proposed water discharge pipeline would be constructed in a similar manner. The corridor would be kept cleared of woody vegetation to allow for pipeline inspection and maintenance. Pipeline construction would disturb 5.2 acres of wetlands based on GIS analysis of aerial photography, NWI and existing wetland mapping, and Level 3 GAP habitat mapping. Most of these wetland impacts are Type 6 shrub swamp (4.5 acres) with the remainder being marsh or aquatic wetland types. Actual permanent wetland impacts would likely be less than 5.2 acres, as some of these wetlands are likely already impacted somewhat by the existing pipeline and berm. In addition, some of the wetland impacts would be temporary in nature as those wetlands not filled by the pipeline berm would be restored to some level of functionality. It is recommended that existing wetland acreages and impacts be delineated prior to issuance of the Final EIS.34
34 Tribal cooperating agencies take the position that this delineation should occur prior to the issuance of the DEIS so that the public can review a complete set of potential impacts from the project.
The capture of approximately 95% of the NorthMet seepage and its discharge to the Partridge River would significantly reduce the rate of groundwater seepage from the Tailings Basin to the downgradient wetlands compared to the Proposed Action and would in fact represent a 83% reduction from existing conditions (i.e., predicted seepage from decrease from an existing 900 gpm to a maximum of 154 gpm; see Table 4.1-78). This reduction in seepage is expected to eliminate any additional indirect wetland impacts north of the Tailings Basin from approximately 349.3 acres under the Proposed Action, to approximately 0 acres under the Tailings Basin Alternative. It is not expected that this diversion of seepage would go so far as converting the existing wetlands to uplands. The total groundwater seepage rate (NorthMet seepage plus residual LTVSMC seepage from Cell 2W) would still exceed aquifer flux capacity during operations and Closure, so some limited inundation of wetlands is still expected to continue, but the inundation would only affect wetlands already indirectly impacted from the existing LTVSMC seepage. The results of transient flow modeling, which was used to predict groundwater quality downgradient from the Tailings Basin, indicate that groundwater would meet all wetland water quality standards (Minnesota Rules parts 7050.0186 and 7050.0222, basically the Class 2B standards from Table 4.1-20). Therefore, indirect wetland impacts from changes in groundwater quality are not expected.35
35 Tribal cooperating agencies disagree with the logic of the previous paragraph. Should it receive permits for its project, PolyMet will assume responsibility for all legacy contamination caused by the tailings basin to surface water, groundwater and wetlands. Therefore, tribal cooperating agencies take the position that the current exceedances, which are the result of decades of untreated discharges from the tailings basin, must be addressed by PolyMet as part of its closure plan.
4.2.4.2 Wetland Mitigation The USACE St. Paul District requires a basic compensation ratio of 1.5:1 (1.5 acres of compensatory mitigation for every one acre of wetland loss) in the northeastern portion of Minnesota where the Project would be located. This ratio can be reduced by qualifying for the following incentives, but can be no less than a minimum 1:1 ratio: • In-place incentive: the project-specific mitigation site is located on-site or within the same 8- digit hydrologic unit code watershed as the authorized wetland impacts, or bank credits are purchased within the same Bank Service area – reduce ratio by 0.25 • In-advance incentive: the project-specific mitigation site must have wetland hydrology and initial hydrophytic vegetation established a full growing season in advance of the authorized wetland impacts, or bank credits are purchased – reduce ratio by 0.25. In-kind incentive: the mitigation wetlands are of the same type (same wetland plant community) as the wetlands authorized to be impacted – reduce ratio by 0.25 If none of these incentives are met, the mitigation ratio required is 1.5:1. If one of the three incentives is met, the required mitigation ratio is 1.25:1; if two or three are met, the ratio is 1:1. According to USACE St. Paul District’s compensatory wetland mitigation policy (USACE 2009, St. Paul District Policy for Wetland Compensatory Mitigation in Minnesota), requirements for mitigation can exceed the 1.5:1 mitigation ratio if the impacted wetlands provide rare or exceptional functions.36
36 Tribal cooperating agencies take the position that the large acreage of wetlands to be directly impacted and the high quality of the wetlands warrant a mitigation ratio of greater than 1.5:1.
4.2.4.4 Mitigation Summary The Proposed Action would impact an estimated 854.2 acres of direct impacts and 667.9 acres predicted indirect impacts (see Table 4.2-4). PolyMet proposes a combination of on-site and offsite mitigation to meet its mitigation requirements. PolyMet’s current mitigation proposal includes: • On-site mitigation totaling 175 acres of wetland creation; • Aitkin Site – 810 acres of wetland restoration and 123 acres of upland buffer preservation; and • Hinckley Site – 313 acres of wetland restoration and 79 acres of upland buffer preservation. Off-site wetland restoration of 1,123.2 acres would provide approximately 1,119.8 wetland mitigation credits. In addition, a total of 202 acres of upland buffer areas are proposed to be established with native vegetation around the wetland restoration areas. In accordance with USACE guidelines, credit for the upland buffer areas is proposed at a 4:1 ratio, resulting in an additional 50.6 wetland credits. The total offsite mitigation would provide 1,170.3 wetland mitigation credits. Compensatory ratios determined in permitting may vary from these assumptions, which would result in a different percentage of mitigated impacts under this plan. Finally, the Closure plan for the site is designed to create or restore 175 acres of wetlands, not included in the mitigation discussed above. It is planned that the additional wetland mitigation would provide 116.7 additional wetland mitigation credits (at an assumed 1.5:1 ratio), for a total of 1,287 wetland mitigation credits. The overall wetland mitigation strategy for the Project is to replace unavoidable wetland impacts in-kind where possible and in advance of impacts when feasible. Due to both on-site and off-site limitations and technical feasibility, it was not found to be practicable to replace all impacted wetland types with an equivalent area of in-kind wetlands. For instance, for the overall Project wetland impacts, the coniferous bog community acreage directly impacted could potentially be 509.5 acres and the total coniferous bog wetlands compensated for would be 339.4 acres (based on assumed ratios), a 170.0 acre compensation deficit (Table 4.2-6). Most other wetland community types proposed to be directly impacted would be replaced with comparable wetland communities. Total proposed on-site and offsite wetland mitigation proposal totals 1,287 mitigation credits (Table 4.2-6). Compensatory mitigation required for the predicted would exceed the direct impacts (854.2 acres), but may not be sufficient to satisfy the compensatory mitigation requirements for the 667.9 acres of indirect impacts for which the mitigation ratio has not yet been determined. Compensatory mitigation for any remaining indirectly impacted acres, plus or minus any adjustments for higher or lower mitigation ratios that may be required, would need to be addressed through permit conditions.37 This mitigation would focus on sites located within the St. Louis River/Great Lakes watershed in accordance with the federal Mitigation Rule, Corps policy, and overall requirements under the Clean Water Act
37 Tribal cooperating agencies take the position that unless the mitigation for the additional 475 wetland acres is identified in the DEIS, or there is a detailed statement of how the permit conditions would address the needed acres, the impacts must be considered unmitigated for purposes of the DEIS.
4.2.5 Cumulative Wetland Impacts 4.2.5.2 Cumulative Wetland Impacts - Partridge River Watershed Study Area The Partridge River watershed study area extends from the headwaters of the Partridge River upstream of the Peter Mitchell Mine to the confluence with the St. Louis River downstream of Hoyt Lakes, Minnesota. The MnDNR Census of the Land (MnDNR 1996, Minnesota Census of the Land) identifies the primary land uses in the watershed as bog/marsh/fen, brushed land, forests, water, cultivated land, hay/pasture/grassland, mining, and urban and rural development. The latter four of these land cover classes were assumed to be associated with human impacts; therefore, the areas classified with any of these four land cover classes were identified as areas in which pre-settlement Trygg wetland data would be used (Trygg 1996). While the primary land use classification bog/marsh/fen combines a variety of wetland types, no fens are known to occur in the Project area.38
38 Tribal cooperating agencies disagree. Tribal cooperating agencies take the position that, based on the data from the wetland delineations, there are fens in the project area. At a regional scale, Iron Range taconite mining has impacted wetlands through direct wetland fill as well as indirect impacts due to air deposition of mine related contaminants, water quality degradation, and the flooding/de-watering of wetlands which lead to changes in wetland functional values. There are two additional geographic scales at which wetland cumulative impacts should be characterized: St. Louis River Watershed. The Fond du Lac band of Lake Superior Chippewa has identified this watershed as an area of concern. The cumulative impact analysis should quantitatively characterize the following: 1. The additive effect of PolyMet related air and water emissions to the Partridge and Embarrass River watershed wetlands and their impact on water quality of the St. Louis River. 2. The loss of wetlands and changes in wetland functional values in the St. Louis River watershed during the 3 timeframes, including a characterization of the potential for future mining impacts and the long-term maintenance requirements of the PolyMet mine as currently proposed. 1859 Ceded Territory. The Fond du Lac, Grand Portage, and Bios Forte tribes retains treaty guaranteed rights to harvest natural resources within the 1859 ceded territory. The cumulative impact analysis should quantitatively characterize the following: 1. The additive effect of PolyMet related air and water emissions to the wetlands of the 1859 ceded territory. 2. The loss of wetlands and changes in wetland functional values in the 1859 ceded territory during the 3 timeframes. 3. Loss of tribal access to wetlands in the 1854 ceded territory due to either the changes documented in 2. above, or due to mitigation of wetland impacts occurring outside of the ceded territory.
Results: Cumulative Effects Analysis The analysis for this study indicated that more than 95% of the existing wetlands in the Partridge River watershed would remain in the foreseeable future with or without the NorthMet Project (Table 4.2-9). The northeastern wetlands of Minnesota are unique within the state as well as most of the other parts of the United States, in that the loss of wetlands has remained relatively small. For instance, it has been estimated that the 48 lower states have lost about 53% of presettlement wetland habitat (http://www.epa.gov), compared to a minimal loss (estimated at less than 1%) in northeastern Minnesota.
Most wetland impacts in the Partridge River watershed have resulted from past LTVSMC and continuing Peter Mitchell Mine operations and would result from the NorthMet Project. The largest wetland impact that has occurred or is proposed to occur is the projected direct loss of 814 wetland acres with the likelihood for an additional 318 acres indirectly impacted by the NorthMet Project; however, even these impacts are small compared to the estimated 33,880 wetland acres currently present in the Partridge River watershed. Wetlands in the study area are similar in type and function to wetlands found throughout this portion of northeastern Minnesota; most are high quality wetlands and consist of black spruce bog/open bog, forested swamp, and alder thicket/shrub carr. No fens have been identified in the Project area.39
39 Tribal cooperating agencies disagree. Based on the data from the wetland delineations, fens have been identified in the project area. Many of the wetlands that have classified as open bogs are poor fens and the wetlands classified as black spruce bogs are rich forested peatlands.
The NorthMet Project and other proposed projects within the Partridge River watershed would primarily impact high quality wetlands with significant functions and values because of the relative isolation and lack of human disturbance in the watershed. Mining activities would cause additional habitat fragmentation as well as loss of wetland functions and values. Relative to the 33,880 wetland acres estimated to occur in the Partridge River watershed (Table 4.2-9), the overall proportion of impacted wetlands from these Projects would be about 3.4%. However, because most of the directly and indirectly impacted wetlands are of high quality the function and values served by the wetlands in the watershed would be expected to be significantly affected by the approximately 814 acres of direct Project wetland impacts and 318 acres of predicted indirect wetland impacts from the Project.40
40 Tribal cooperating agencies take the position that the impacts to these wetland acres is significant.
The mitigation plan as described in Section 4.2.4.2 addresses the compensatory plans to offset the proposed wetland impacts if the mitigation sites are permitted and achieve the required performance levels, but most of the proposed mitigation would occur outside of the Partridge River watershed and outside the 1854 Ceded Territory.41
41 Tribal cooperating agencies take the position that 475 acres of required mitigation has not been addressed.
4.2.5.3 Cumulative Wetland Impacts – Embarrass River
Results: Cumulative Effects Analysis
Most wetland impacts in the Embarrass River watershed have resulted from past LTVSMC operations, development of recreational areas, including the Giants Ridge Ski Resort, and would result from the East Mine Reserve and NorthMet Projects. The largest wetland impact that has occurred or is proposed to occur is the projected indirect loss of 352 wetland acres by the NorthMet Project; however, even these impacts are small compared to the estimated 39,473 wetland acres currently present in the Embarrass River watershed. Wetlands in the study area are similar in type and function to wetlands found throughout this portion of northeastern Minnesota; most are high quality wetlands and consist of wet meadow, black spruce bog/open bog, shallow marsh, and alder thicket/shrub carr. No fens have been identified in the Project area.42
42 Tribal cooperating agencies disagree. Based on the data from the wetland delineations, fens have been identified in the project area. Many of the wetlands that have classified as open bogs are poor fens and the wetlands classified as black spruce bogs are rich forested peatlands.
The NorthMet Project within the Embarrass River watershed would primarily impact low quality wetlands that are adjacent to the tailings basin. Relative to the 39,473 wetland acres estimated to occur in the Embarrass River watershed (Table 4.2-10), the overall proportion of impacted wetlands from the Project would be about 0.8%. Since most of the impacted wetlands are of low quality the function and values served by the wetlands in the watershed would not be expected to be significantly affected by the approximately 320 acres of predicted indirect wetland impacts from the Project.43
43 Tribal cooperating agencies take the position that the impacts to these wetland acres is significant.
4.2.5.4 Summary The mitigation plan as described in Section 4.2.4.2 addresses the compensatory plans to offset the proposed wetland impacts if the mitigation sites are permitted and achieve the required performance levels, but most of the proposed mitigation would occur outside of the Partridge River and Embarrass River watersheds and outside the 1854 Ceded Tribal Lands.
4.3 VEGETATION 4.3- Several plant species have been identified as being of significant tribal concern including wild rice, cedar, and sage. These species are relatively common to northeastern Minnesota; therefore, loss of access to these areas is not anticipated to have a significant impact on tribal use of these plant species. There is no documented tribal use of the Plant and Mine Sites for harvesting these resources.1 1 It is the tribal cooperating agencies’ position that while there is no current documented tribal use of vegetation resources, band members do not always report their harvest sites. Therefore, it should not be assumed that there is no use of resources in these areas. Tribal cooperating agencies also note that the Area of Potential Effect for the Project was not determined until August 11, 2009 and that tribal consultation is ongoing. Therefore, historic and current tribal harvest information has not been determined for either the Plant or Mine Sites.
4.3.1 Existing Conditions 4.3.1.1 Cover Types
4.3.1.2 Threatened and Endangered Plant Species
4.3.1.2 Threatened and Endangered Plant Species 4.3-5 4.3.2 Impact Criteria 4.3.3 Environmental Consequences 4.3.3.1 Proposed Action
Project construction, operation, and closure at the Plant Site would have minimal effects on native vegetation because most of the Plant Site (62 percent) has already been heavily disturbed or is barren (Table 4.3-6). Most of proposed impacts are to isolated stands of forest characterized as being in fair condition. Other impacts to cover types at the Plant Site are minor.2 2 The tribal cooperating agencies’ position is that although this area is significantly disturbed and will be for the foreseeable future, the closure and reclamation plans should have a significant effect on native vegetation as it is reintroduced. The prevalence of invasive, non-native species and their ability to out-compete native plants in disturbed areas, coupled with PolyMet’s plan to introduce non-native and invasive species to this area, would result in significant impacts.
Use of the proposed seed mix and mulch would introduce invasive non-native species to an area of primarily natural vegetation. These species, once introduced, are difficult to remove and could spread to and colonize susceptible areas following future disturbance (e.g., blowdown, logging, fire). These species may reduce diversity, out-compete native vegetation, and provide lower quality habitat for some specialist animal species. Dominance by invasive non-native species would reduce the quality of native cover types and habitat remaining at the Project.3 3 It is the tribal cooperating agencies position that native plant species have evolved over millennium and thus have adapted to local climatic conditions. Therefore, these native species should be used in any re-vegetation efforts. The use of non-native plants should be avoided. Seed mixes using native plants can be developed with the desired establishment and groundcover capabilities.
Reclamation and revegetation at the Mine Site would initiate vegetative succession on stockpiles and at the East Pit. The stockpiles would be planted with red pine on the slopes and seeded with grasses/forbs at the tops and bench flats (to minimize the potential for deep-rooted trees from penetrating the cap). Within a few decades, the slopes should be occupied by forest.4 4 The tribal cooperating agencies’ position is that the use of mono-culture red pine plantations to mitigate should be avoided. The importance of a variety in tree species in the ecosystem to provide suitable habitat for a greater variety of wildlife species cannot be understated.
4.3.3.2 No Action Alternative 4.3-17 4.3.3.3 Mine Site Alternative 4.3-18 4.3.3.4 Tailings Basin Alternative 4.3-18 4.3.3.5 Other Mitigation Measures 4.3-18 4.3.4 Cumulative Effects 4.3-19 4.3.4.1 Summary of Issue 4.3-19 4.3.4.2 Approach to Analysis 4.3-20 4.3.4.3 Existing Baseline Conditions and Past Losses 4.3-21 4.3.4.4 Environmental Consequences of Reasonably Foreseeable Actions on ETSC Plant Species 4.3-22
Given its tolerance for disturbance, the cumulative effects of the Project and other reasonably foreseeable activities are not expected to jeopardize the presence of E. nitida in Minnesota or North America.5 5 It is the tribal cooperating agencies’ position that too much emphasis is placed on this species ability to tolerate disturbance. Given that the Project could affect nearly one-third of populations of this species, this could jeopardize the presence of the species in Minnesota.
This species inhabits non-forested wetlands (e.g., sedge meadow, poor fen, and lakeshore). Forest harvesting would not affect the non-forested wetland habitat of this species. Given its tolerance for disturbance, the cumulative effects of the Project and other reasonably foreseeable activities are not expected to jeopardize the presence of S. glomeratum in Minnesota or in North America.6 6 It is the tribal cooperating agencies’ position that too much emphasis is placed on this species ability to tolerate disturbance
4.4 WILDLIFE 4.4-1 |