ANACONDA MINE SITE Groundwater Investigation Community Meeting January 31, 2013

1. ANACONDA MINE SITE Groundwater Investigation Community Meeting January 31, 2013 U.S. Environmental Protection Agency Region 9 Superfund Division

2. Agenda U.S. Environmental Protection Agency Region 9 Superfund Division

3. Anaconda Yerington Mine Site Operable Units U.S. Environmental Protection Agency Region 9 Superfund Division

4. Site-wide Groundwater (OU-1) Introduction U.S. Environmental Protection Agency Region 9 Superfund Division

5. Site-wide Groundwater (OU1) • Purpose of tonight’s meeting • Respond to community request for more information • Describe work accomplished in last three years • Present an overview of current groundwater conditions • Describe remaining data gaps and Remedial Investigation workplan designed to fill those gaps U.S. Environmental Protection Agency Region 9 Superfund Division

6. EPA Superfund Investigation and Remediation Process Highlights • Discovery of Contaminated Site • Preliminary Assessment/Site Inspection • Remedial Investigation/Feasibility Study • Record of Decision • Remedial Design/Remedial Action • Site Reuse/Redevelopment U.S. Environmental Protection Agency Region 9 Superfund Division

7. Site-wide Groundwater (OU1) • Remedial Investigation workplan submitted by Atlantic Richfield is the plan to complete the data gathering necessary to identify and evaluate options for remediation in the Feasibility Study U.S. Environmental Protection Agency Region 9 Superfund Division

8. Site-wide Groundwater (OU1) • Data gathered in last three years have provided a much better picture of groundwater flow and horizontal and vertical extent of contamination • Characterization of off-site chemical concentrations in the deep portions of the aquifer and in the north/northeast portion of the site • Characterization of on-site chemical concentrations to better determine the most significant source areas • Better understanding of groundwater flow, especially deep flow, and the influence of high capacity wells U.S. Environmental Protection Agency Region 9 Superfund Division

9. Site-wide Groundwater (OU1) • Now have robust network of wells to provide information and monitor concentration and movement of contaminants • Monitoring network expanded from approximately 110 wells to over 300 wells • Monitoring network includes wells of the Yerington Paiute Tribe • Wells are sampled/monitored quarterly U.S. Environmental Protection Agency Region 9 Superfund Division

10. Site-wide Groundwater (OU-1) Brown and Caldwell Presentation U.S. Environmental Protection Agency Region 9 Superfund Division

11. Site-wide Groundwater (OU-1) Wrap-Up U.S. Environmental Protection Agency Region 9 Superfund Division

12. Site-wide Groundwater (OU1) • Background Characterization • Background Groundwater Quality Assessment - Revision 1 (Submitted) • Evaluation of Tracer Data (Estimated Completion Date: June 2013) • Background Work Plan (Estimated Submittal Date: December 2013) • Chemical Transport • Aquifer Solids Testing Work Plan (Approved) • Objectives for Groundwater Flow Modeling (Approved) • Groundwater Flow Model Work Plan (Submitted) • Additional Characterization Activities (Estimated for June – December 2013) • Bedrock Characterization • Initial Bedrock Characterization Work Plan (Approved) • Implementation (Estimated Completion Date: June 2013) • Data Summary Report (Estimated Completion Date: September 2013) • Bedrock Work Plan (Estimated Submittal Date: December 2013)

13. Agricultural Assessment • Groundwater (OU1) Investigation • Effects of agricultural pumping on groundwater/chemical movement • Effects of irrigation application on groundwater/chemical movement • Effects of use of fertilizers, etc. on groundwater chemistry • Wabuska Drain (OU7) Investigation (Scoping planned soon) • Effects of sediment deposition on land adjacent to Drain • Effects of surface water/localized groundwater on land adjacent to Drain • Human Health Risk Assessments • Evaluation of pathways for exposure to site-related contamination • Evaluation of impacts on agricultural products affected by completed pathways • Evaluation of human health impacts from exposure to affected agricultural products

14. Site-wide Groundwater (OU1) U.S. Environmental Protection Agency Region 9 Superfund Division

15. Site-wide Groundwater (OU-1) Q & A U.S. Environmental Protection Agency Region 9 Superfund Division

16. Process Areas (OU-3) Workplan Overview U.S. Environmental Protection Agency Region 9 Superfund Division

17. Process Areas (OU3) Workplan U.S. Environmental Protection Agency Region 9 Superfund Division

18. Process Areas (OU3) Workplan • Designed to characterize contamination in soil from surface to water table • What contaminants are in the soil and at what levels? • What are the potential past and current contributions to groundwater contamination? • How and where are the contaminants moving? • What are the risks to human health and the environment? • What options are available for cleanup? U.S. Environmental Protection Agency Region 9 Superfund Division

19. Process Areas (OU3) Workplan • Builds on data from previous characterizations • Areas with known occurrences of mine-related chemicals • Areas where concentrations of contaminants increase with depth • Areas where concentrations of contaminants exceed background or screening levels • Areas which have not been adequately characterized or have not been investigated previously U.S. Environmental Protection Agency Region 9 Superfund Division

20. OU3 Workplan Example Sub-Area 3 Proposed Soil Sample Locations

21. Open Forum U.S. Environmental Protection Agency Region 9 Superfund Division

22. EPA Project Team U.S. Environmental Protection Agency Region 9 Superfund Division

23. EPA Project Management Assignments U.S. Environmental Protection Agency Region 9 Superfund Division