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A New Environmental Threat in the Upper Great Lakes Region:

Sulfide Mining

Prepared for:National Wildlife Federation

Prepared by:Ann Maest, PhDRichard Streeter

Stratus ConsultingBoulder, CO

andBob Prucha, PhD, PE

Integrated Hydro SystemsBoulder, CO

19 March 2011

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Geographic Extent of Proposed Mining Copper and other base metal deposits are wide-

spread in the upper Great Lakes region – associated with midcontinental rift

Deposits are concentrated in Upper Peninsula of Michigan and Minnesota near Duluth (copper, nickel, platinum group metals, gold, uranium)

Prospects are located on and near National Forest and tribal lands

Some deposits and proposed processing plants are within a few kilometers of Lake Superior or Lake Michigan

Increase in exploration associated with increased worldwide demand (led by China and India) and increasing metal prices

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Midcontinent Rift

Rocks in the midcontinent rift are an important source of copper and silver.

Source: http://www.geo.lsa.umich.edu/teaching/Bedrock%20v6.pdf

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Overview of Potential Mines and Associated Facilities

See references for project locations and commodities.

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Potential Environmental Impacts

Mine development will impact wetlands, surface water, groundwater, landscapes, aquatic and terrestrial biota, and human health

Potential effects include– Destruction of wetlands and terrestrial habitat

from mine facilities– Draining of wetlands and lowering of

groundwater levels from dewatering– Metal and acid contamination of streams,

wetlands, stream sediment, aquatic invertebrates, fish, groundwater, drinking water wells, and surface runoff

– Mine subsidence (collapse affects land surface, waterways)

Regulatory agencies not adequately staffed to review proposals or manage new mining

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Screening methods used to identify potential environmental impacts from the proposed mines and projects

Used largely industry sources for location of mine projects; assigned confidence levels for locations

Estimated amount of groundwater, wetlands, streams, and disturbed areas potentially affected by proposed projects – see reference section for details

Measured amount of historically disturbed area at the Eagle and Northmet sites

Calculated amounts of potentially disturbed waters and lands are likely underestimates of actual mine-related disturbance and effects (e.g., does not include groundwater)

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Minnesota Projects: Potentially Affected Surface Water Resources

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Eagle and Eagle East Projects: Potentially Affected Surface Water Resources

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Humboldt Mill: Historic Tailings Areas and Potentially Affected Waterways

Potential

Escanaba R.

Note: Former pit will be filled with tailings and impact streams to north

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Extent of Potential Wetland and Stream Impacts

Extent of potentially impacted wetlands at least 7,320 acres– Includes wetlands within ¼ mile of Eagle

Haul Road and areas within 1-mile radius of project area (predicted size of cone of depression for Eagle Project)

Extent of potentially impacted streams at least 441 miles– From project areas downstream to dam

or large lake Likely underestimates impacts

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Potential Groundwater Impacts

Many communities rely on groundwater for drinking water

Mine dewatering operations could decrease availability of groundwater for many uses– Eagle will pump 113 million gallons/yr– NorthMet will pump up to 599 million gallons/yr

Development of mines could contaminate groundwater during and after mining and adversely affect human health

Following slides show alluvial aquifers (bedrock aquifers are also at risk of contamination) and known well locations

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Known Wells and Alluvial Aquifers in Upper Peninsula of MI and Northeastern Wisconsin

See references for sources of aquifer and well locations. USGS atlas does not include smaller continuous aquifer systems.

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Known Wells and Alluvial Aquifers in Northern Minnesota

See slide 4 (overview map) for regional location.

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Potentially Impacted Wells and Groundwater Pumping

Wells in vicinity of projects in Michigan and Minnesota on previous maps: 429 to 652 wells– Lower number is for wells within 1-mile radius, higher

for 2-mile radius– Only includes existing domestic wells in vicinity of

projects with high confidence of location• For example, there are 29 domestic wells

between NorthMet site and Embarrass River to the north

– Does not include wells in Wisconsin – no state database

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Loss of Groundwater Use from Dewatering Operations Groundwater pumping

– Eagle Project estimates:• Estimated pumping ranges from 75 to 215

gallons/minute over nine years of operation– NorthMet Project estimates:

• Dewatering will lower flows in Partridge River, drawdown levels in Whitewater Reservoir, and lower groundwater levels

• Estimated pumping ranges from 200 to 1,150 gallons/minute over 20 years of operation

Sources: Foth & Van Dyke and Associates. 2006a; NorthMet DEIS, 2009.

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Loss of Groundwater Use from Dewatering Operations (cont.)

– Water pumped at a subset of the projects in this study would supply between 76,000 to 407,000 people per year with domestic water• See methods file – used mine-estimated

dewatering rates for Eagle and Northmet – Using 2009 census estimates, the projects would

use more water annually than Kalamazoo, Michigan (73,000 people) on the low end and Minneapolis (385,000 people) on the high end

– Estimates of water use are probably low because they do not include likely expansion of operations or inaccuracies on the upper bound of water use

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Contaminants of Concern

Most base metal sulfide mines have similar contaminants of concern– Metals: arsenic, cadmium, copper, lead, nickel, zinc– Non-metals: sulfate (from acid drainage), nitrate and

ammonia (from blasting agents used to excavate mine), cyanide (from flotation operations)

– Acid: acid drainage (from mined materials), low pH Metals do not degrade to less toxic compounds and are

toxic to aquatic life at low concentrations Mineral deposits and surrounding rock in Upper Great

Lakes area are predicted to create acid drainage and leach high concentrations of nickel and copper (see following slides for Eagle Project, MI)

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Health Impacts from Mine-related Contaminants

Liver or kidney damage: copper, cadmium, lead Learning impairment in children: lead Blue baby syndrome: nitrate Known or suspected carcinogen: arsenic Nerve damage/thyroid problems: cyanide Toxic to fish and aquatic biota at low concentrations:

cadmium, copper, lead, zinc, ammonia Impacts wild rice: sulfate

Sources:US EPA, 2011.

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Data source: Geochimica, 2004, Phase I column 4 (12.85%S) .

Eagle Project, MI: Sulfate, pH, and nickel values in leachate from semi-massive ore unit

Up to 1,200 times higher than MI water quality standard (0.1 mg/l)

Up to almost 2.5 times higher than MI water quality standard (250 mg/l)

More acidic (lower pH) than acceptable range (6.5-8.5) for US drinking water

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acidic

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Data Source: Geochimica, 2004, Siltstone, Phase II column 4 (1.39%S).

Eagle Project, MI: Sulfate, pH, and copper values in leachate from surrounding rock

Up to over nine times higher than MI water quality standard (1.4 mg/l)

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acidic

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Movement of Contaminants

Contaminants move away from mine to groundwater and surface water

Groundwater feeds wetlands and streams – decreasing groundwater levels and quality can dry up surface waters

Metals remain in environment for millennia Metals move from water to sediment to

aquatic bugs to fish to piscivorous mammals and birds

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Contaminants in the Environment

Contaminants can be transferred back and forth between shallow groundwater and streams

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Contaminants move downstream with the water and sediment, exposing aquatic biota

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Impacts from Similar Mines

Mines with high potential to generate acid and leach contaminants – and in close proximity to water resources – have the most adverse environmental effects of all hardrock mines (Kuipers and Maest, 2006)– 85% of these mines exceeded surface water

quality standards due to mining releases Proposed mines in the upper Great Lakes have

these same inherent characteristics that lead to contamination regardless of commodity and mining method

Water quality standards are exceeded even though permit limits are in place and permit applications stated standards would not be exceeded

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Impacts from Similar Mines (cont.)

Known water quality effects from modern sulfide mines near water resources are shown in the following table

Other effects include fish kills and reproductive and behavioral effects, draining and destruction of wetlands, lowering of shallow groundwater levels, depletion of stream and spring flows

Impacts from Modern Sulfide Mines in Wet Climates

Mine Name, State

Ownership Commodity Operation Type Water Quality Impacts

Flambeau (Ladysmith), WI Kennecott Copper, gold, silver Open pit, flotation

Groundwater exceedences of manganese, pH, sulfate, dissolved solids from pit backfill; exceedences of copper in stream on site.

Greens Creek, AKHecla Mining

CompanySilver, lead, zinc,

gold Underground, flotationSurface water contaminated with acidity, sulfate, zinc from tailings/waste rock

Black Pine, MT ASARCO Copper, gold, silver Underground, flotationSprings contaminated with sulfate, copper, zinc, cadmium, acid drainage from waste rock dump.

Golden Sunlight, MT

Placer Dome, Inc. (now Barrick

Gold) GoldUnderground and open

pit, vat leach

Groundwater contaminated with cyanide and copper from tailings; acid drainage in waste rock and open pit.

Stillwater, MTStillwater Mining

CompanyPlatinum group

metals Underground, flotation

Groundwater contaminated with nitrate, chromium, sulfate, cadmium, zinc from adit drainage; increased nitrate in surface water.

Beal Mountain, MT Pegasus Gold Co. Gold, silver Open pit, heap leach

Groundwater/surface water increases/exceedences of nitrate, cyanide, sulfate from heap leach and waste rock

Grouse Creek, IDHecla Mining Company Gold, silverOpen pit, heap and vat

leachGroundwater and surface water contaminated with cyanide from tailings leakage

Thompson Creek, ID

Cyprus/Thompson Creek Mining Co. Molybdenum Open pit, flotation

Surface water contaminated with cadmium, copper, lead, sulfate, zinc from tailings and waste rock seepage; acid drainage in wastes and pit

Zortman and Landusky, MT Pegasus Gold Co. Gold, silver Open pit, heap leach

Groundwater and surface water contaminated with metals, acidity, nitrate, and cyanide

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Similar Mining Districts

Sudbury, Ontario, Canada– Rich copper, nickel, platinum group metal (PGM) sulfide

deposits: 8th richest mining district in world– Formed by meteor impact, but also has massive sulfide

deposits like the Eagle Project in Michigan (acid generators)– Extensive and severe soil and vegetation contamination

from smelting; groundwater contamination from acid-generating mine wastes

Duluth, Minnesota, USA– Duluth deposit has produced low-pH drainage (as low as

4.5 to 6.4) and high metal concentrations (e.g., up to 22 mg/L copper

Following slides show many mines and prospects in Sudbury – there are similar geology, size, and commodities in Baraga and could be similar impacts

See attachment: Comparison to other base metal ultramafic deposits

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Sudbury District, Canada: >200 Nickel-Copper-PGE Deposits

Source: Ames and Farrow, 2007

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Baraga Basin Geology – Similar Structure and Commodities to Sudbury

Source: Prime Meridian Resources.http://www.primemeridianres.com/i/maps/baraga/baraga-01.jpg

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Historical Mining Impacts in the Upper Great Lakes Have Not Been Cleaned Up Historic iron mining destroyed landscapes –

less impact to water quality because mines were generally not acid producers

Impacts to land have not been remediated New mining will destroy landscapes and

adversely affect groundwater and surface water quality and quantity

Need to clean up old contamination before new mining begins

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Ongoing Mining Impacts: near Palmer, Upper Peninsula, Michigan

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Historic Mining Impacts:Duluth Complex

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Historic Copper and Iron Mining Districts

Sources: mining areas = http://www.mg.mtu.edu/shaft0.htm. Surficial geology = USGS http://tin.er.usgs.gov/geology/state/state.php?state=MI

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Specific Projects

Eagle Project in Michigan and NorthMet in Minnesota are in permitting stage or have already been permitted– Expected land disturbance = 144 acres at

Eagle Project and 6,430 acres at NorthMet Others range from initial to full-scale exploration Specific information on mine plans and potential

impacts for the Eagle Project and NorthMet Project are included in the following slides

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Eagle Project, Michigan

Project has been approved by State of Michigan– Project is in native ceded territory– Main river (Salmon Trout) flows into Lake

Superior Copper, nickel in massive sulfide deposit with high

acid drainage and contaminant leaching potential Potential for contamination of groundwater and

surface water, loss of water from wetlands, loss of water from Salmon Trout River

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Eagle Project, Michigan (cont.)

Underground mine; transport along haul road for flotation processing; discharge of treated water at ground surface– Existing water and soil contamination at

Humboldt Mill site (tailings area) has not been addressed

– Close to residential well, and groundwater is contaminated with arsenic, manganese, vanadium

Water and contaminant flow during and after mining are shown in the following slides

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Eagle Project: Flows during Mining

Mine immediately beneath Salmon Trout River; flow in river could decrease from mine dewatering operations

Discharge from Treated Water Infiltration System (TWIS) will not meet surface water standards

Extensive groundwater impacts – contaminants will likely travel along extensive permeable faults

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Eagle Project: Flows after Mining

Contaminated water from mine could flow to downgradient groundwater, Salmon Trout River, and Lake Superior

Contaminants would include metals and acid from mining and brine from deep groundwater encountered during mining

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NorthMet Project, Minnesota

First non-ferrous (sulfide) mine in Mesabi Range: Copper, nickel, platinum group metals

Three open pits, large disturbed area (>6,000 acres)

Located within Superior National Forest, land ceded by Indian tribes where they exercise their treaty rights

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NorthMet Project, Minnesota: Impacts Predicted in EIS

All waste rock is acid generating Water quality exceedences in Partridge River, Embarrass

River, Colby Lake, St. Louis River Tailings basin will leak contaminants to groundwater Increased mercury loadings from waste rock to Lake

Superior watershed Direct impacts to > 1,000 acres of wetlands; inadequate

mitigation plan Assumes maintenance-free closure; no financial

assurance information EPA rated EIS an EU3 (environmentally unacceptable)

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NorthMet Project

Source: NorthMet DEIS, 2009.

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NorthMet Project: Impacted Wetlands

Source: NorthMet DEIS, 2009.

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Summary

Upper Great Lakes region is at risk, with widely distributed base metal, precious metal, and uranium deposits

Deposits are sulfide-rich, and mining them can be more environmentally harmful than historic iron mining, especially to water quality

Estimates of potential adverse effects in this study are likely lower than actual effects

Mining of similar deposits has consistently caused water quality problems

Regulatory agencies are not adequately staffed to review proposals or manage new mining

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References

See files for report, data, and website references.