mtg agenda: public fs workshops, 12/10 - agenda ... · public fs workshops tuesday, december 10, 7...

LAVA CAP MINE SUPERFUND SITEPUBLIC FS WORKSHOPSTuesday, December 10, 7 pm

SFUND RECORDS CTR130329

AGENDA

Sign-In, Multi-Voting

Introductions

Review Agenda and Workshop Process(EPA/Don Hodge)

Site Update (EPA/Dave Seter)

Review of Workshop Materials(EPA/Valentina Cabrera-Stagno):Design CriteriaTechnologiesCombined Alternatives

Break:Review Workshop MaterialsMulti-Voting

Workshop/Feedback Session(EPA Facilitator/Don Hodge)

10 minutes

10 minutes

10 minutes

15 minutes

15 minutes

15 minutes

45 minutes


Lost Lake - Design Criteria

• Reduce total estimated human health risk from multipleexposure points at a level within the range of excess lifetimecancer risk of IxlO'6 to IxlO"4, and the non-cancer hazardreduced to background levels.

• Minimize the potential for migration of soil and sediment thatexceeds the cleanup goal.

• Minimize the potential for release of contaminated tailingsduring a seismic event producing 60 percent groundacceleration or 0.3g.

• Minimize the potential for release of contaminated sedimentsduring surface-water flow up to the 100 year-storm event.

• Attain water quality standards established under federal andstate law.

• Reduce risks to ecological receptors.


Lost Lake Clean-Up -- Technologies

1

2

3

4

5

6

7

8

Channelize Clipper Creek

Vegetate bare areas inDeposition Area

Excavate contaminatedsediment along ClipperCreek

Stabilize Clipper Creek

Dredge channel throughLost Lake

Cap and revegetate LostLake and Deposition Area

Stabilize shore ofDeposition Area

Clipper Creek diversionstructure with high- andlow-flow channels

To prevent erosion of tailings by surface water. Channel dimensions: 10 ft. wide at the base, 10 ft. deep; sidessloped 1 ft.-to-2 ft. Construction: 60-mil HDPE (high density polyethylene) liner, mesh screens filled withapproximately 6-in. diameter rocks.

To control erosion of tailings in Deposition Area by wind and water. Plant native revegetation in bare areas,approximately 3.8 acres total.

To prevent further movement of contaminated sediment. Excavate and remove contaminated sediment alongClipper Creek.

To prevent erosion of tailings by surface water. Place riprap of quarry rock sized 3 to 18 in. in sections of thecreek with higher potential for scour. Revegetate all disturbed areas.

To retard flow toward the spillway to 1.5 feet per second, to reduce scour and suspended tailings. Dredge achannel through tailings and dispose of tailings in landfill cell above the Deposition Area. Channeldimensions: 300 ft. long, 8 ft. deep and 50 ft. wide. Cell dimensions: 75 ft. wide, 180 ft. long, and 9 ft. deep.

To prevent contact with and movement of contaminated sediment. Cap with 2 ft. of clean soil and revegetate.Soil required, Deposition Area: 40,600 cubic yards; Lost Lake: 23,800 cubic yards.

To prevent erosion of Deposition Area sediments into the lake. Shape and grade shore to a 1 ft.-to-2 ft. slopeand coyer with 3 ft. of riprap consisting of angular quarry rock sized 6 to 18 in. in diameter.

To prevent erosion of contaminated soils by surface water. Construct diversion channels of reinforced concretewith concrete lined spillway over dam and large boulders and rip rap at the bottom for energy dissipation .Channel dimensions: 10 ft. wide at base, between 5 and 10 ft. deep, 1 ft.-to-2 ft. slope. Spillway dimensions:20 ft. wide, 9 ft. high retaining walls.


Lost Lake Clean-Up -- TechnologiesUnderwater cap on LostLake sediment

To prevent movement of and contact with contaminated sediments. Regrade lake shore to 1 ft.-to-3 ft. orshallower slope and smooth bottom of lake. Install 60-mil HOPE liner with air vents; cover with a minimumof 18 in. of clean soil.

Treatment plant belowLost Lake dam

To prevent contamination from moving downstream of Lost Lake. Construct a treatment plant near the base ofthe dam to collect seepage and treat it continuously with GFH (an iron-based medium which absorbs arsenicfrom contaminated water).

Lowering Lost Lake dam To stabilize the dam if Lost Lake is drained. Reduce dam height by 10 ft. and the spillway 10 ft., and gradethe downslope face to a 1 ft.-to-2.5 ft. slope.

Excavate contaminatedsediment in Lost Lake andDeposition Area

To remove contaminated sediment. Drain Lost Lake and excavate an estimated volume of 350,000 cubic yardsfrom the Deposition Area and 150,000 cubic yards from Lost Lake. Grade the shore of Lost Lake allow torefill. Lost Lake will increase from 5 to approximately 20 acres in area.

Dispose of contaminatedsediment on-site

To prevent contact with removed contaminated sediments. Dispose of an estimated volume of 500,000 cubicyards of contaminated sediment in an onsite disposal cell. Cell would include liner, cover, and leachatecollection system.

Dispose of contaminatedsediment off-site

To prevent contact with removed contaminated sediments. Truck an estimated volume of 500,000 cubic yardsof contaminated sediment away from the site to a landfill. Construct access road; improve and repair Lost LakeRoad, Hoppy Hollow Road, and Greenhorn Road.

Renovate Lost Lake dam To prevent movement of contamination downstream by improving seismic stability and accommodating a 500-year storm. Renovate Lost Lake dam; construct a rock-fill buttress on the downslope face at a 1 ft.-to-2.5 ft.slope, using cobbles and boulders up to 3 ft. in diameter. Widen spillway to 10 ft. Excavate and removecontaminated sediment at the toe of Lost Lake dam.

Phyto-remediation ofDeposition Area

To reduce contaminant concentration in soil and reduce air-borne movement of contaminated soil. Plant andharvest arsenic hyper-accumulating ferns over a period of several growing seasons. Install chain-link fencearound the ferns to limit human and wildlife interaction with the hyper-accumulated arsenic.

Lost Lake Area -- Example Clean-up Alternatives

Remedial Action Techno- Amount of Construe- Limita- Limita-logies construe- tion tions on tions on

tion traffic property recreationactivity use

Total50-year

cost

Clipper Creek up- and downstream of Lost Lake

3-25-2

3-35-3

3-45-4

Restrict access and use L VL M H

Channelize CC and cap sediment 1 M L M L

Excavate contaminated soil and dispose onsite 3 M M L L13

0.5 M

2.7 M

1.0 M

Lost Lake and Deposition Area4-2

4-3

4-4

Stabilize CC 4 M M H HDredge channel through Lost Lake 5Vegetate bare areas

215

Cap and revegetate deposition area 2,7,1,8, H M H LStabilize shore of deposition area 9,10,15Channelize CCConstruct a CC diversion structureUnderwater cap on Lost LakeTreat seepage from dam

Drain Lost Lake 6,11,1,15 H M H LCap and revegetate lake and Deposition AreaLower Lost Lake damChannelize CC and western tributaries

1.9 M

l l .OM

8.5 M

VL=Very Low, L=Low, M=Medium, H=High, VH=Very High

Lost Lake Area -- Example Clean-up Alternatives

4-5

4-6

pilot

Remedial Action

Excavate contaminated sediment from LostLake and Deposition AreaDispose of contaminated sediment onsite

Excavate contaminated sediment from LostLake and Deposition AreaDispose of contaminated sediment offsite

Phyto-remediation of Deposition Area(rest similar to 4-2)Stabilize CCDredge channel through Lost LakeVegetate bare areas

Techno- Amount oflogics construc-

tionactivity

12, 13, 15 H

12, 14, 15 H

16, 15 M

Construc-tion

traffic

H

VH

M

Limita-tions onproperty

use

M-H(landfillareas)

L

H

Limita-tions on

recreationi

M-H(landfillareas)

L

H(in pilot

area)

Total50-year

cost

19.0 M

83.0 M

similar to4-2

Renovate Lost Lake Dam (occurs in allalternatives)

15 M M-H

VL=Very Low, L=Low, M=Medium, H=High, VH=Very High


NCR CRITERIA(Regulations require that ERA evaluate the proposed cleanupusing these nine criteria)

• Overall Protection of Human Health and the Environment

• Compliance with ARARs1 or "other laws''

• Long Term Effectiveness, and Permanence

• Reduction of Toxicity, Mobility, or Volume (of contaminants)

• Short-Term Effectiveness (how quickly cleanup is achieved,also construction impacts)

• Implementability (technical and administrative feasibility)

• Cost

• State Acceptance

• Community Acceptance

'ARARs/Applicable or Relevant and Appropriate Requirements


Feedback Worksheet

1. Did you come out of the workshop with a better understanding of the factors that will gointo developing the cleanup plan for the Lost Lake Area? If not, what additionalinformation do you need from EPA?

2. The "design criteria" presented by EPA help to determine what type structures to build aspart of the cleanup. The more conservative (or more protective) the criteria, the largerand more expensive the structures tend to be. Do you have any comments on the size andtype of structures that may be needed as described by EPA? Are the design criteria tooconservative? Not conservative enough?

3. You have been asked to vote on the end results you would like to see when the Lost LakeArea cleanup is complete. Now that EPA has presented some of the possible cleanupalternatives, which one best fits your vision of the end results you would like to see?

4. The Lost Lake Area is made up of parcels of land owned by many different landowners.If the landowners disagree on the type of cleanup to be built, problems could result. Doyou have any suggestions for EPA on how best to communicate with the landowners andbuild consensus on the cleanup plan?

5. EPA described a planned "phytoremediation" pilot project which would test the ability offerns to clean up arsenic from the soil. Part of the project will involve planting one ormore test plots of ferns. Would you be willing to have EPA plant ferns on your propertyas part of the pilot project?

6. Do you have any other questions for EPA on the Lost Lake Area cleanup? Please listthem here.


SummaryLava Cap Mine Community Meetings, November 2001

EPA asked participants to express their greatest concerns regarding the site and to provide inputon specific methods that we might use in the cleanup. Responses are summarized below.

Public ConcernsCommunity members most often cited groundwater and well safety as a concern, since many ofthem have wells on their property. Quality of the lake water for recreation and fishing was also aconcern. Community members asked questions about a range of other concerns:• possibility of continuing contamination;• the stability of existing tailings;• the continuing presence of mining equipment and supplies on Banner Mountain and potential

contamination at Banner Mine;• whether the Lava Cap mine is officially closed or could potentially operate again• the possible presence of mercury or methyl-mercury;• the possible presence of other components used in the mining process;• the impact of contamination on local wildlife and ecology;• and finally, interest in the site generally.Other comments concerned poor communication with the EPA:• one well owner had not been contacted with the results of tests done at his well• another expressed shock that they would not have known about the contamination if they had

not run across a flier.

Input on Clean-up Options• strong desire to keep Lost Lake (two people)• need for Little Greenhorn Creek to remain open to the public• desire for local contractors' involvement in the clean-up process (two comments).• requirement for restoration of Tensy Lane if used for truck access.• suggestion to return the surface of the area to its original state before it was a tailings

impoundment, with subsurface drainage for tailings and covered with vegetation.• suggestion to move the arsenic-containing mass out and bury it in a lined area.• desire for a "more permanent solution" with a suggestion to "remove it all, clean it down to

nothing".• statement about the possibility for more passive ways to clean up arsenic such as phyto-

remediation.

Requests By Community Members to EPA• type up "sheets" and make them available to the public• provide a map of tested wells to the public


NotesLava Cap Mine Community Meetings, November 2001

Evening Meeting (11/13/01)Agenda6:45 Sign In7:00 Agency / Staff Introductions

Agenda Overview7:15 Community Introductions and Initial Concerns7:30 EPA Presentation: Risk Assessment8:00 TAG Presentation: Community Activities8:15 Community Discussion: Clean-up options: What would you like to see us do to clean-up

this site?9:00 Wrap-up and adjourn

Community Concerns• Well safety.• Downstream, lack of communication with EPA.• Concerned with everything.• General concern/info.• Concerned with dam.• Quality of groundwater, contamination of shoreline, effects on wildlife.• Keep abreast of situation.• General info (everything).• General.• Worried about Banner Mine/Lava Cap impact on well.• Water quality of Lake.• General and well safety.• General and water quality.• General.• Water quality, groundwater, and surface water; known issues and potential issues that haven't

surfaced.

Questions on EPA's Presentation• How did you determine which wells to test?• No one contacted me after I gave permission to sample. Was sample computed? Poor

communication.• I have friends who fish in that lake and are eating the fish.• Map of tested wells - request.• Fed program that will test my water/well?• How far out from creek did you test? (50 ft)

• What about the fish, rabbit/hare?• Migratory birds? Impacts?• What forms of mercury did you sample for? Methyl-mercury more toxic.• Would a fish look different if contaminated?• What about other components used in the mining process?

Day Meeting (11/14/01)Agenda2:15 Sign In2:30 Presenter/Agency Intro2:45 Community Introductions

Where do you live?What are your most pressing concerns?

3:00 EPA Presentation: Risk Assessment3:30 TAG Presentation3:45 Clean-up Options

Community Discussion: How would you clean-up the site? What should EPA do?4:30 Wrap-up and Adjourn

Community Concerns• Neighbor had arsenic in well, concerned with safety. Hasn't had water tested.• Concerned about Lake and flow into Rollins and airborne contamination.• Amount of money the EPA spends only about 12% is spend on actual remediation; the rest

on overhead. Concerned same thing will happen here. Fraud/contractors. Does project needto happen at all?

• Has well with 187 ppb arsenic using for landscape (144 ppb EPA); drilled second well (160ft) 2.8 ppb

• Are you looking at Banner Mine?• General information• General info.• Concerned with Clipper Creek and Little Clipper Creek - possible contamination to well.• Work available for local contractors (Nevada City Co.)• Testing - 50 ppb on well. Drink bottle water.• Creek, soil; well water 37.5 ppb, has reverse osmosis unit; how is cap on tailings to be

maintained?

Questions on EPA's Presentation• What method do you use to test for arsenic? (some methods are controversial)• Has EPA established standards for arsenic in air and solids?• Explain PRO values for cancer/non-cancer.• Explain Hazard Ranking System (Index)• Could wells penetrate mine shaft?• What is clean-up goal for arsenic (in ppb)?• Is there any type of cancer associated with arsenic?• Can you measure arsenic in the blood?• I've been drinking 140+ ppb water for 9 months - could it still be detected in my body?

Community Input on Clean-up Options• How much excavation are you talking about?• How much right does EPA have to come in (vs private property rights)• If trucks were on Tensy Lane, we would want road restored.• Will money be kept local? We would be more open to truck traffic if it was a local business.• Is the mine officially closed? Could they re-open it?• If you choose the alternative involving capping what land use restrictions would there be?• How much of the tailings are underwater?• I'm a lakefront property owner -1 am distressed to hear about the medium + "no action"

alternative (in reference to getting rid of lake). I don't want my property values to beimpacted by no clean-up.

• Are there passive ways to clean up arsenic? e.g. plants• If tailings were removed, would new soil be brought in?• If you do away with Lost Lake what happens to outflow from mine?

Banner mine water is connected.• Does excavation include dredging of Lost Lake.• What would be level of truck traffic involved with capping?

How do you guarantee integrity of capping / plastic liner over 100+ years?• Why has it taken so long?• Mine equipment / supplies (55 gallon drums) still on Banner Mountain.• If mine used mercury, why don't you find more of it? Could it be hidden?

Questions on TAG's Presentation• What is treatment method for arsenic?• Body contact (bathing)/dermal exposure? Request for ppb level.• What is background level for arsenic?

Input on Clean-up Options• Draining the Lake - no way• Little Greenhorn Creek - need access to remain open to public.• Return surface to original state - before mining impoundment area - storm sewer, subsurface

drainage for tailings, cover with vegetation.• Easy to cart tailing away but these options do not address what is underneath. Ground Water

is important to us. Needs to be a priority - don't ignore.• What are possible impacts to wells from remediation options?• Move arsenic mass out (mobile) bury in lined areas.• Can this happen again? Stability of existing tailings?• More permanent answer is to remove it all. Clean it down to nothing.• (Response to previous comment) Where would you take it?• How will you choose an option? Where do we come in?• How limited are you by cost?• Seems like this will take years. Seems like higher population sites will get greater priority.• If I hadn't received flier - I wouldn't have known. Put me on mailing list!• Type sheets up - make available to public on the web.

CAG technical advisor: Dr. Lee (530) 753-9630

LAVA CAP MINE SUPERFUND SITECOMMUNITY WORKSHOPS ON CLEANUP ALTERNATIVESTuesday, December 10, 2002, 7 pm

MULTI-VOTING EXERCISEQuestion for workshop participants: For the Lost Lake Area cleanup, which end result would you most like to see?

Procedure: Each participant receives five dots. Participants can vote all five dots for one outcome category, one dot for five outcomecategories, or any other combination.

Preferred result Votes

Ecological restoration

Preservation of scenic/aesthetic value

Restoration of recreational value

Least possible exposure of people to lakesediments/tailings/dust

Things as they are now

Other (please write in below)

mtg agenda: public fs workshops, 12/10 - agenda ... · public fs workshops tuesday, december 10, 7...

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