Upload
national-wildlife-federation
View
2.255
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Sulfide mine development will impact wetlands, surface water, groundwater, landscapes, aquatic and terrestrial biota, and human health in the Lake Superior basin. This presentation prepared for the National Wildlife Federation looks at the potential impacts of sulfide mining on the region's groundwater, waterways and health.Prepared by:-Ann Maest, PhD-Richard Streeter, Stratus Consulting, Boulder, CO and-Bob Prucha, PhD, PEIntegrated Hydro Systems, Boulder, CO
Citation preview
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
Overview of Potential Mines and Associated Facilities
See references for project locations and commodities.
STRATUS CONSULTING
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
STRATUS CONSULTING
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)
STRATUS CONSULTING
Minnesota Projects: Potentially Affected Surface Water Resources
STRATUS CONSULTING
Eagle and Eagle East Projects: Potentially Affected Surface Water Resources
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
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.
STRATUS CONSULTING
Known Wells and Alluvial Aquifers in Northern Minnesota
See slide 4 (overview map) for regional location.
STRATUS CONSULTING
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
STRATUS CONSULTING
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.
STRATUS CONSULTING
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
STRATUS CONSULTING
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)
STRATUS CONSULTING
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.
STRATUS CONSULTING
0
100
200
300
400
500
600
0 10 20 30 40 50 60 70
SO
4 (m
g/l)
SO4
0.00
2.00
4.00
6.00
8.00
10.00
0 10 20 30 40 50 60 70
pH
pH
0
20
40
60
80
100
120
0 10 20 30 40 50 60 70
Ni (
mg
/l)
Ni
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
Weeks
Weeks
Weeks
acidic
STRATUS CONSULTING
0
100
200
300
400
500
0 10 20 30 40 50
SO
4 (m
g/l)
SO4
0.00
2.00
4.00
6.00
8.00
10.00
0 10 20 30 40 50
pH
pH
0.02.04.06.0
8.010.0
12.014.0
0 10 20 30 40 50
Cu
(mg
/l)
Cu
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)
Weeks
Weeks
Weeks
acidic
STRATUS CONSULTING
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
STRATUS CONSULTING
Contaminants in the Environment
Contaminants can be transferred back and forth between shallow groundwater and streams
979
969
Contaminants move downstream with the water and sediment, exposing aquatic biota
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
Sudbury District, Canada: >200 Nickel-Copper-PGE Deposits
Source: Ames and Farrow, 2007
STRATUS CONSULTING
Baraga Basin Geology – Similar Structure and Commodities to Sudbury
Source: Prime Meridian Resources.http://www.primemeridianres.com/i/maps/baraga/baraga-01.jpg
STRATUS CONSULTING
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
STRATUS CONSULTING
Ongoing Mining Impacts: near Palmer, Upper Peninsula, Michigan
STRATUS CONSULTING
Historic Mining Impacts:Duluth Complex
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
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
STRATUS CONSULTING
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)
STRATUS CONSULTING
NorthMet Project
Source: NorthMet DEIS, 2009.
STRATUS CONSULTING
NorthMet Project: Impacted Wetlands
Source: NorthMet DEIS, 2009.
STRATUS CONSULTING
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
STRATUS CONSULTING
References
See files for report, data, and website references.