former asarco smelter east helena facility annual rcra

Montana Environmental Trust Group, LLCTrustee of the Montana Environmental Custodial Trust

Former ASARCO Smelter East Helena FacilityAnnual RCRA Corrective Action Update

December 8, 2020


Agenda• Welcome and Opening Remarks (EPA)• RCRA Corrective Action Status– Work Completed to Date– Final Remedy Selection– Corrective Measures Implementation

• Groundwater Quality Update• Slag Removal Project• Property Redevelopment• Public Participation• Questions


Corrective Actions Required by First Modification to Consent Decree

ProcessüRCRA Facility Investigation (RFI)

üPreliminary Human Health and Ecological Risk Assessments (HHRA and BERA)

üCorrective Measures Study (CMS)

üEPA Selection of Final Remedy

ØCorrective Measures Implementation (CMI)

Interim

Measures


All Former ASARCO Properties Addressed By RCRA Corrective Action


Final Remedy Proposal Based on Comprehensive Technical Evaluations

• 2011-2014: Studies conducted to evaluate and design the IMs– Upper Lake Drawdown Test– MVS modeling– Stream flow assessments– Delineation of groundwater plumes

• 2014-2015: Identification and further investigation of key source areas

• 2015: Identification and screening of remedial alternatives

• 2016: Detailed alternative evaluation and final remedy proposal

• 2013-to date: IM performance groundwater monitoring

Predictive Ground-

water Modeling


EPA’s Final Remedy Selection Statement of Basis - July 2020

üEvapotranspiration (ET) Cover SystemüSouth Plant Hydraulic ControlüSource Removal & Corrective Action Management

Units (CAMUs)üSpeiss-Dross Slurry WallØ Slag Pile CoverüInstitutional Controls

ØCustodial Trust deed restrictionsüCity and County Ordinances


SourceRemoval

Area(Acid Plant)

East Helena Completed Corrective Measures


ü Minimizes long-term stewardship.Ø No active operations (i.e., pump and treat system).Ø Natural cover and PPC realignment require less maintenance than

man-made materials/technologies.

ü Eliminate the need to manage and treat stormwater.ü Maximize use of sustainable remediation approaches.

Ø Natural systems.Ø No energy requirements.Ø No emissions.

ü Develop and evaluate alternatives that allow continued asset recovery from slag pile.Ø Design will accommodate future recovery.Ø Cover can be modified in future if market conditions change.

Final Corrective Measures Meet Site-Specific Remedial Action Objectives


Corrective Measures Implementation (CMI)

• CMI Work Plan submitted to EPA on October 8, 2020• Corrective Measures Implementation (CMI) – Long-term performance monitoring– Design & construction of slag pile cover system– Institutional controls (i.e., land-use restrictions)– Operation and maintenance

§ CAMUs§ ET Cover


Final Corrective Measures Performance Evaluations

Engineering Controls

Corrective Measures Performance Evaluation

Purpose Data to Be Collected and Evaluated

ET Cover and

Slag Pile Cover

• Prevent direct contact with contaminated soils/slag

• Reduce contaminant leaching to groundwater by reducing infiltration of precipitation

• Inspection of cover condition (vegetation, visual evidence of holes, erosion, etc.)

• Groundwater elevations (changes with precipitation)

• Groundwater quality

South Plant Hydraulic Control

• Lower groundwater elevations in South Plant to reduce contact with contaminated soils

• Groundwater elevations in South Plant


Focused Source Removal

• Remove accessible, localized areas of contaminated soil


Maintain CAMUs• Protectively manage hazardous

waste• Inspection of covers• Groundwater quality• Leachate volumes

Speiss-DrossSlurry Wall

• Prevent groundwater contact with highly contaminated source material

• Prevent migration of contaminated groundwater within wall

• Groundwater elevations across wall• Groundwater quality


Institutional ControlsCorrective Measures Performance Evaluation

Purpose Data to Be Collected and Evaluated

Private Well Abandonment Program

Eliminate potential exposure

Presence of functioning private well

Deed Restrictions on Custodial Trust Property

Ensure use is protective Confirmation that land use is consistent with restriction

Institutional Controls Implemented By Others

Controlled Groundwater Area

Control exposure to potentially contaminated groundwater

Review of permit status

City Well Restrictions(COEH Municipal Code,

Zoning Ordinance Title 8, Chapter 3, Section 8.3.7)

Control exposure to potentially contaminated groundwater

Review of private water well status

Soils Ordinance Required by OU-2 Record of Decision

(Adopted by county June 2013)

Prevent direct contact with contaminated soil

Review of soil arsenic and lead concentrations within the established administrative boundary


Ø Corrective Action Monitoring Plan (CAMP)Ø Groundwater Level TrendsØ Groundwater Quality TrendsØ Plume Stability Update

2019/2020 Groundwater Monitoring Results


• Phase II RCRA Facility Investigation (2010-2012)• Upper Lake Dewatering Evaluation (2011-2012)• Downgradient Selenium Plume Delineation

(2012-2016)• 2014 Source Area Investigation and Report• 2015 Source Area Investigation and Report• Annual Groundwater/Surface Water Corrective

Action Monitoring Program§ Monitoring plans prepared and implemented

annually 2010 through 2020§ Monitoring reports prepared annually 2015

through 2019 (2020 report in preparation)

Groundwater Related Investigations and Studies Since 2010

Predictive Ground-

water Modeling2010-2016


Primary Source Areas• West Selenium Area• North Plant Arsenic Area• Former Speiss-Dross Area• Former Acid Plant Area• South Plant• Slag Pile

Corrective Measuresü South Plant Hydraulic Controlü Source Removalsü Evapotranspiration (ET) Coverü Speiss-Dross Slurry WallØ Slag Pile Cover

Groundwater Contaminant Source Areas Addressed by

Corrective Measures


Corrective Action Monitoring Program (CAMP)Primary Objective• Collect groundwater and surface water data to

evaluate water resources response to Corrective Measures

Performance Monitoring Components• Groundwater Level Trend Analyses: Evaluate

effectiveness of SPHC and ET Cover at lowering groundwater levels and reducing groundwater interaction with contaminated soils.

• Groundwater Quality Trend Analyses: Collect groundwater quality data to document water quality trends at individual source area and downgradient monitoring wells.

• Plume Stability Evaluation: Collect groundwater quality data from established subset of plant site and downgradient wells to determine plume areas, average concentrations and plume centroid locations for annual comparison.


2020 Annual Monitoring

• Semi-annual Groundwater Monitoring§ 23 wells in spring§ 78 wells in fall

• Semi-annual Residential/Water Supply Well Monitoring in 20 wells

• Semi-annual Surface Water Monitoring at 7 locations• Water Levels at 187 Wells and 9 Surface Water

Elevations (Spring/Fall)


Groundwater Elevation Trends


Potentiometric Map

(October 2019)


October 2016 October 2020

Groundwater Selenium Plume


October 2016 October 2020

Groundwater Arsenic Plume


Selenium Plume Trends


Arsenic Plume Trends


Plume Stability Analysis – SeleniumPlant Site

Downgradient

YearPlanar Area

(acres)Average

Concentration (mg/L)

2010 74 0.112

2014 111 0.123

2015 112 0.121

2016 114 0.136

2017 79 0.108

2018 74 0.078

2019 82 0.088

2020 79 0.086

YearPlanar Area

(acres)Average Concentration

(mg/L)

2010 67 0.451

2016 48 0.270

2017 35 0.230

2018 52 0.340

2019 51 0.240

2020 33 0.220

0

10

20

30

40

50

60

70

80

2010 2016 2017 2018 2019 2020

Plume Area (acres)

Year

Plant Site Selenium Plume Area Trend

0.00

0.10

0.20

0.30

0.40

0.50

2010 2016 2017 2018 2019 2020Average Concentration (mg/L)

Year

Plant Site Selenium PlumeAverage Concentration Trend

0

20

40

60

80

100

120

2010 2014 2015 2016 2017 2018 2019 2020

Plume Area (acres)

Year

Downgradient Selenium Plume Area Trend

0.0000.0200.0400.0600.0800.1000.1200.1400.160

2010 2014 2015 2016 2017 2018 2019 2020Average Concentration (mg/L)

Year

Downgradient Selenium Plume Average Concentration Trend


Plant Site

Downgradient

60

65

70

75

80

85

2010 2016 2017 2018 2019 2020

Plume Area (acres)

Year

Plant Site Arsenic Plume Area Trend

0.000.250.500.751.001.251.501.752.002.252.50

2010 2016 2017 2018 2019 2020Average Concentration (mg/L)

Year

Plant Site Arsenic PlumeAverage Concentration Trend

01020304050607080

2010 2014 2015 2016 2017 2018 2019 2020

Plume Area (acres)

Year

Downgradient Arsenic Plume Area Trend

0.000

0.050

0.100

0.150

0.200

0.250

2010 2014 2015 2016 2017 2018 2019 2020

Average Concentration (mg/L)

Year

Downgradient Arsenic PlumeAverage Concentration Trend

YearPlanar Area

(acres)Average Concentration

(mg/L)

2010 82 2.25

2016 77 1.29

2017 77 1.19

2018 69 0.94

2019 71 1.02

2020 72 1.04Year

Planar Area (acres)

Average ArsenicConcentration (mg/L)

2010 66 0.203

2014 68 0.167

2015 68 0.175

2016 64 0.167

2017 65 0.173

2018 68 0.211

2019 66 0.203

2020 66 0.173

Plume Stability Analysis – Arsenic


Additional Corrective Measures May Be Implemented Based on Monitoring Results

• Long-term monitoring required to demonstrate effectiveness of corrective measures

• Need for additional corrective measures will be evaluated if monitoring indicates performance criteria are not met

• Corrective action approach to date:– Already showing improvements in groundwater quality; and– Has preserved sufficient funds to implement additional future

remedies, if needed.


East Helena Slag Removal Project

üRemove 2,000,000 tons of unfumed slag

üTransport to South Korea for re-processing§ Rail to Port of Longview, Washington§ Ship from Washington to South Korea

ü Project Schedule§ Construction 12/2020 to 4/2021§ 4/2021 begin shipping slag§ 20,000 tons/month (2021)/30,000 tons (2022)§ Project complete in 5 years

ü Corrective Measure: Slag Re-grade and Cover§ CMS allowed for slag recovery§ Proceed with Slag Pile corrective measure after removal complete§ Source removal (75% selenium)

ü Cost savings for cover and puts money into EHCU Account


Stockpile Area (300,000 sf)sufficient for 6 months load out @

22k tons/month; 132k tons (@ 20 ft tall = ± 80,000 sf @ 150 lb/cf and

area for loader to run while loading feeder to overland

Stockpile Feeder Location

Overland Conveyor

Rail Spur Route

Rail Loadout Area

Million Gallon Tanks to be removed by

MCC/HSG. Sand and 4” slab and walls

below tanks.

Crusher Location

Radial Stacker to stockpile along with loader to load overland feeder.

Dashed Line = Conveyors from Crusher Location to Stockpile Location.

Main Access through South Entrance Gate

ReclaimedNo Go Zone

ReclaimedNo Go Zone

ET Cover ReclaimedNo Go Zone

Mine and Crusher Area


Montana Environmental Trust Group, LLCTrustee of the Montana Environmental Custodial TrustMontana Environmental Trust Group, LLCTrustee of the Montana Environmental Custodial Trust

K:\PROJECT\10022\Slag Pile\2016 Tech Memo\Figures - Exhibits\Fig 11 - SchematicSummary.srf

DH

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DH

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DH

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DH

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DH

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DH

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DH

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DH

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~40-

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~40'

~60'

Pre-Early 1940sUnfumed Slag

(estimated boundary)

Post-1982Unfumed Slag

Fumed Slag

BorrowPit

organic clay layer sand/silt layer

South Slag WellsSe <= 0.005K <= 8.2SO4 <= 202

DH-55Se = 0.200K = 175SO4 = 752

DH-56Se = 0.777K = 395SO4 = 1377

DH-74Se = 0.143K = 145SO4 = 547

DH-75Se = 0.024K = 27SO4 = 553

DH-6Se = 0.497K = 179SO4 = 867

area of increasinggroundwater concentrations

DH-56As = 113Cu = 1,445Zn = 11,283

DH-69As = 379Cu = 1,535Se = 73Zn = 50,980

DH-74 (60-107')As = 79Cu = 1,772Se = 10Zn = 12,319

DH-74 (0-42')As = 1,399Cu = 12,094Se = 154Zn = 103,960DH-55 (0-20')

As = 268Cu = 4,245Zn = 13,161

DH-55 (20-75')As = 114Cu = 1,846Zn = 8,968

DH-76 (0-42')As = 654Cu = 8,863Se = 168Zn = 114,573

DH-76 (45-97')As = 1,227Cu = 8,252Se = 50Zn = 83,845

Average GWConcentrationsin mg/L

Average SlagConcentrationsin mg/kg

00.10.20.30.40.50.60.70.80.91

2007 2008 2009 2010 2011 2012 2013 2014 2015

Se (m

g/L)

Date

DH-55

00.20.40.60.81

1.21.41.61.82

2007200820092010201120122013201420152016

Se (m

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Date

DH-6 DH-15

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0

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1

1.5

2

2.5

3

2002 2004 2006 2008 2010 2012 2014 2016

As (m

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Date

DH-52

00.51

1.52

2.53

3.54

4.55

2002 2004 2006 2008 2010 2012 2014 2016

As (m

g/L)

Date

DH-56DH-56

FIGURE

11SCHEMATIC SLAG PILE

CROSS-SECTION ANDSUMMARY OF FINDINGS

EXISTING INFORMATION ANDDATA COMPILATION FOR THE

FORMER EAST HELENA SMELTERSLAG PILE AREA

Upper Lift of Slag Pile


§ 75% of Selenium Plume from Upper Lift§ Reduce height of Slag Pile by more than 50%


East Helena Redevelopment Project

Property Sold or Transferred

GreenwayProject

Property

Natural Resource Damage Option

Property


Greenway Project

§ Prickly Pear Land Trust

§ Public Access to Prickly Pear Creek

§ Approximately 5.4 miles of trail in East Helena

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Recent Public Participation and Outreach• World Montana Site Tour• City Council Site Tour• City Council Presentations• Groundwater Technical Working Group Update• Carroll Students Tours• Prickly Pear Land Trust Tours• Support of Prickly Pear Junction• Custodial Trust Website:

https://www.mtenvironmentaltrust.org/east-helena/– Link to 2020 CMS Addendum:

https://www.mtenvironmentaltrust.org/2020-corrective-measures-study-cms-report-addendum/

https://www.mtenvironmentaltrust.org/east-helena/

https://www.mtenvironmentaltrust.org/2020-corrective-measures-study-cms-report-addendum/


Questions?

• If you have called in, you can unmute by pressing: *6

• If you have participated by Zoom, please use the Chat feature at the bottom of the screen


More Information• Visit the Custodial Trust Website:


• Contact:– Betsy Burns, U.S. Environmental Protection

Agency, (406)457-5013, [email protected]– Cindy Brooks, Montana Environmental Trust

Group, (617)448-9762, [email protected]


former asarco smelter east helena facility annual rcra

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