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Silver Bow Creek/Butte Area Superfund Site

Submissions from 2026 2026

Final 2022 Insufficiently Reclaimed Sites Sampling: BRES No. 38 – Sister Dump Site Evaluation Summary Report, Pioneer Technical Services, Inc.

Final 2022 Insufficiently Reclaimed Sites Sampling: BRES No. 96 – Washoe Dump Site Evaluation Summary Report, Pioneer Technical Services, Inc.

Final 2022 Unreclaimed Sites Sampling: UR-06 Site Evaluation Summary Report, Pioneer Technical Services, Inc.

Final 2022 Unreclaimed Sites Sampling: UR-07 Site Evaluation Summary Report, Pioneer Technical Services, Inc.

Final 2022 Unreclaimed Sites Sampling: UR-12 Site Evaluation Summary Report, Pioneer Technical Services, Inc.

Final 2022 Unreclaimed Sites Sampling: UR-13 Site Evaluation Summary Report, Pioneer Technical Services, Inc.

Final 2022 Unreclaimed Sites Sampling: UR-20 Site Evaluation Summary Report, Pioneer Technical Services, Inc.

Final 2022 Unreclaimed Sites Sampling: UR-22 Site Evaluation Summary Report, Pioneer Technical Services, Inc.

Final 2022 Unreclaimed Sites Sampling: UR-28 Site Evaluation Summary Report, Pioneer Technical Services, Inc.

Final 2022 Unreclaimed Sites Sampling: UR-28 Site Evaluation Summary ReportFinal 2022 Unreclaimed Sites Sampling: UR-28 Site Evaluation Summary Report, Pioneer Technical Services, Inc.

Final Annual Operations and Maintenance (O&M) Report: Butte Treatment Lagoon (BTL) System – 2023, Pioneer Technical Services, Inc.

Final Basinwide Quality Management Plan (QMP) – 2026-2030, Revision 0, Pioneer Technical Services, Inc.

Final BPSOU Unreclaimed Sites: UR-46 Remedial Action Work Plan (RAWP), Pioneer Technical Services, Inc.

Final Butte Priority Soils Operable Unit (BPSOU) Unreclaimed Sites: UR-08 (Anderson Shaft) Remedial Action Work Plan (RAWP), Pioneer Technical Services, Inc.

Final Butte Priority Soils Operable Unit (BPSOU) Unreclaimed (UR) Sites New and Mahoney (UR-23) Construction Completion Report (CCR), Pioneer Technical Services, Inc.

Final Insufficiently Reclaimed Sites Quality Assurance Project Plan (QAPP), Pioneer Technical Services, Inc.

Final Quarterly Operations and Maintenance Report Butte Treatment Lagoon System – First Quarter 2025, Pioneer Technical Services, Inc.

Final Quarterly Operations and Maintenance Report: Butte Treatment Lagoon System – Fourth Quarter 2025, Pioneer Technical Services, Inc.

Final Quarterly Operations and Maintenance Report: Butte Treatment Lagoon System – Third Quarter 2025, Pioneer Technical Services, Inc.

Final Revised Silver Bow Creek Conservation Area (SBCCA) Construction Quality Assurance Plan (CQAP), Pioneer Technical Services, Inc.

Final Silver Bow Creek Conservation Area Materials Management Plan, Pioneer Technical Services, Inc.

Final Silver Bow Creek Conservation Area (SBCCA) Construction Quality Assurance Plan (CQAP), Pioneer Technical Services, Inc.

Final Unreclaimed Sites Quality Assurance Project Plan (QAPP), Pioneer Technical Services, Inc.

Revised Draft Final Butte Priority Soils Operable Unit (BPSOU) Insufficiently Reclaimed Sites Josephine Shaft (BRES No. 37) Remedial Action Work Plan (RAWP), Pioneer Technical Services, Inc.

Revised Draft Final Butte Priority Soils Operable Unit (BPSOU) Unreclaimed (UR) Sites New and Mahoney (UR-23) Construction Completion Report (CCR), Pioneer Technical Services, Inc.

Revised Draft Final Butte Priority Soils Operable Unit (BPSOU) Unreclaimed (UR) Sites New and Mahoney (UR-23) Construction Completion Report (CCR), Pioneer Technical Services, Inc.

Revised Draft Final Quarterly Operations and Maintenance Report: Butte Treatment Lagoon System – Second Quarter 2025, Pioneer Technical Services, Inc.

Butte Priority Soils Operable Unit Butte Reduction Works Smelter Area Intermediate 60% Remedial Design Submittal, Pioneer Technical Services, Inc. and Atlantic Richfield Company

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) 2022 Draft Final Insufficiently Reclaimed Sites Sampling: BRES No. 16 Site Evaluation Summary Report, Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Draft Final 2024 Reclamation Improvement Sampling: BRES No. 78 – Original Mine Yard Site Evaluation Summary Report, Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Draft Final Rock Creek Cattle Company Borrow Submittal #2 (dated February 4, 2026), Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Draft Final Unreclaimed Sites: UR-27 Site Evaluation Summary Report (SESR), Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Draft Final Whitehall Borrow Submittal #3 (dated March 27, 2026), Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Final Unreclaimed Sites Field Sampling Plan (FSP) Package #7: UR-01, UR-12, UR-03, UR-04, UR-15, and UR-17 Amendment (dated April 28, 2026), Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Revised Draft Final 2022 Unreclaimed Sites Sampling: UR-06 Site Evaluation Summary Report (dated December 10, 2025), Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Revised Draft Final 2022 Unreclaimed Sites Sampling: UR-12 Site Evaluation Summary Report (dated December 9, 2025), Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Revised Draft Final 2022 Unreclaimed Sites Sampling: UR-22 Site Evaluation Summary Report (dated December 10, 2025), Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Revised Draft Final Insufficiently Reclaimed Sites Joesphine Shaft (BRES No. 37) – Remedial Action Work Plan (RAWP) (dated March 24, 2026), Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Revised Draft Final Unreclaimed Sites: New and Mahoney (UR-23) Construction Completion Report (CCR), Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Revised Draft Final Unreclaimed Sites: UR-07 Site Evaluation Summary Report (SESR), Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Unreclaimed Sites: UR-03 Construction Completion Report (CCR), Molly Roby

Re: Approval letter for the Butte Priority Soils Operable Unit - Draft Final 2022 Insufficiently Reclaimed Sites Sampling: BRES No. 96 – Washoe Dump Site Evaluation Summary Report, Molly Roby

Re: Approval letter for the Draft Final 2026 Butte Priority Soils Operable Unit (BPSOU) McDermott Basin Creek Water Treatment Plant Subsurface Fill Borrow Submittal #1, Molly Roby

Re: Approval letter for the Draft Final 2026 Butte Priority Soils Operable Unit (BPSOU) Type B Borrow Material Submittal #3 (dated May 6, 2026), Molly Roby

Re: Comment letter for the Butte Priority Soils Operable Unit (BPSOU) 2025 Butte Reclamation Evaluation System (BRES) Field Evaluation Summary Report and Technical Recommendations Proposal, Molly Roby

Re: Comment letter for the Butte Priority Soils Operable Unit (BPSOU) 2025 Butte Reclamation Evaluation System (BRES) Site Specific Corrective Action Plans for Quadrant 2, Molly Roby

Re: Comment letter for the Butte Priority Soils Operable Unit (BPSOU) 2026 Revised Draft Final Backfill and Cover Soil Quality Assurance Project Plan (QAPP) (dated January 5, 2026), Molly Roby

Re: Comment letter for the Draft Final Butte Priority Soils Operable Unit (BPSOU) Insufficiently Reclaimed Sites BRES No. 30 – Atlantic 1 Remedial Action Work Plan (RAWP) (dated March 24, 2026), Molly Roby

Re: Conditional approval letter for the Butte Priority Soils Operable Unit (BPSOU) 2026 Revised Draft Final Backfill and Cover Soil Quality Assurance Project Plan (QAPP) (dated May 13, 2026), Molly Roby

Re: Conditional Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Draft Final Potential Logan, Montana, Borrow Source Site Environmental Assessment Checklist, Molly Roby

Re: Conditional approval letter for the Butte Priority Soils Operable Unit (BPSOU) Draft Final Unreclaimed Sites: UR-46 Remedial Action Work Plan (RAWP), Molly Roby

Re: Conditional approval letter for the Butte Priority Soils Operable Unit (BPSOU) Draft Final Unreclaimed Sites: UR-46 Site Evaluation Summary Report (SESR), Molly Roby

Re: Conditional Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Revised Butte Hill Revegetation Specifications (dated August 15, 2025), Molly Roby

Re: Conditional Approval letter for the Butte Priority Soils Operable Unit Draft Final 2022 Insufficiently Reclaimed Sites Sampling: BRES No. 50 – Zelia Site Evaluation Summary Report, Molly Roby

Re: Conditional approval letter for the Butte Priority Soils Operable Unit Insufficiently Reclaimed Sites Quality Assurance Project Plan, Molly Roby

Re: Conditional Approval letter for the Draft Final 2024 Unreclaimed Sites Sampling: UR-21 Site Evaluation Summary Report, Molly Roby

Re: Conditional Approval letter for the Draft Final Butte Priority Soils Operable Unit (BPSOU) Insufficiently Reclaimed Sites Sister Dump (BRES No. 38) Remedial Action Work Plan (RAWP), Molly Roby

Re: Conditional approval letter with comments for the Draft Final 2026 Residential Metals Abatement Program (RMAP) Anselmo Mine Yard Development Plan (dated February 25, 2026), Molly Roby

Re: Approval Letter for Draft Final Silver Bow Creek Conservation Area (SBCCA) Butte Reduction Works (BRW) Air Monitoring for Interim Demolition Activities – Phase II Data Summary Report (DSR) (dated June 26, 2026), Emma Rott

Re: Approval letter for the 2022 Butte Priority Soils Operable Unit (BPSOU) Stormwater Evaluation and Maintenance Report (dated April 8, 2026), Emma Rott

Re: Approval letter for the 2023 Butte Priority Soils Operable Unit (BPSOU) Stormwater Evaluation and Maintenance Report (dated April 8, 2026), Emma Rott

Re: Approval letter for the 2024 Butte Priority Soils Operable Unit (BPSOU) Stormwater Evaluation and Maintenance Report (dated April 8, 2026), Emma Rott

Re: Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Draft Final Quarterly Operation and Maintenance Report: Butte Treatment Lagoons (BTL) System– Fourth Quarter 2025 (dated March 30, 2026), Emma Rott

Re: Approval letter for the Butte Priority Soils Operably Unit (BPSOU) Revised Draft Final Quarterly Operations and Maintenance Report: Butte Treatment Lagoon System (BTL) Second Quarter 2025 (dated April 10, 2026), Emma Rott

Re: Approval letter for the Diggings East 100% Remedial Design Package Submittal (dated July 23, 2026), the 100% SBCCA Programmatic Technical Specifications Submittal (Technical Specifications) (dated May 29, 2026), the Final Revised Silver Bow Creek Conservation Area (SBCCA) Construction Quality Assurance Plan (CQAP) (dated July 29, 2026), the Final SBCCA Construction Monitoring Quality Assurance Project Plan (QAPP) (dated July 29, 2026), and the Final SBCCA Materials Management Plan (MMP) (dated July 29, 2026), Emma Rott

Re: Approval letter for the Final Repository Siting Study (RSS) Detailed Evaluation and Recommendations Report (dated February 11, 2026), Emma Rott

Re: Comment Letter for BPSOU Blacktail Creek Riparian Actions Uniform Federal Policy Quality Assurance Project Plan Addendum (dated April 24, 2026), Emma Rott

Re: Comment Letter for Butte Priority Soils Operable Unit (BPSOU) Draft Diggings East Dewatering Treatability Study Pre-Design Investigation Work Plan (PDIWP) (dated August 24, 2026) and the 2026 Draft Diggings East Dewatering Treatability Study Quality Assurance Project Plan (QAPP) (dated August 24, 2026), Emma Rott

Re: Comment Letter for Butte Priority Soils Operable Unit (BPSOU), Draft Intermediate (60%) Remedial Design Report, Blacktail Creek Riparian Actions (dated March 13, 2026), Emma Rott

Re: Comment Letter for Butte Priority Soils Operable Unit Draft Leak Detection Monitoring Plan (dated February 2026), Emma Rott

Re: Comment Letter for Draft Clark Tailings Consolidated Waste Management Area (CTCWMA) 2024 Data Summary Report (dated October 15, 2025), Emma Rott

Re: Comment Letter for Draft Final 2026 Interim Site-Wide Groundwater Monitoring Quality Assurance Project Plan (dated April 17, 2026), Emma Rott

Re: Comment Letter for Old Butte Silver Bow Landfill/Clark Tailings Consolidated Waste Management Area (CTCWMA) Remedy Effectiveness Evaluation Phase I (Conceptual Site Model) (dated February 27, 2026), Emma Rott

Re: Comment letter for the 2020 through 2024 Surface Water Compliance Evaluation Technical Memorandums Silver Bow Creek Area NPL Site, Butte Priority Soils Operable Unit (BPSOU) Consent Decree-Civil Action No. CV89-039-BU-SHE (dated February 3, 2026), Emma Rott

Re: Comment letter for the Butte Priority Soils Operable Unit (BPSOU) Draft 2022 Stormwater Evaluation and Maintenance Report (dated February 27, 2026), Emma Rott

Re: Comment letter for the Butte Priority Soils Operable Unit (BPSOU) Draft 2023 Stormwater Evaluation and Maintenance Report (dated February 27, 2026), Emma Rott

Re: Comment letter for the Butte Priority Soils Operable Unit (BPSOU) Draft 2024 Stormwater Evaluation and Maintenance Report (dated February 27, 2026), Emma Rott

Re: Comment letter for the Draft Final Butte Mine Waste Repository Operations and Maintenance (O&M) Plan (dated May 8, 2026), Emma Rott

Re: Comment letter for the Draft Final Butte Priority Soils Operable Unit (BPSOU) Butte Treatment Lagoons (BTL) Groundwater Treatment System Quarterly Operation and Maintenance Report – Quarter 1 2026 (dated June 26, 2026), Emma Rott

Re: Comment letter for the Revised Draft Final Butte Priority Soils Operable Unit (BPSOU) Butte Treatment Lagoon (BTL) System Annual Report – 2025 (dated May 11, 2026), Emma Rott

Re: Comment Letter for the Silver Bow Creek/Butte Area NPL Site Butte Priority Soils Operable Unit, 60% Remedial Design Documents for the Blacktail Creek Area Groundwater Hydraulic Control System (dated March 2, 2026), Emma Rott

Re: Conditional Approval Letter for Butte Priority Soils Operable Unit Draft Final Leak Detection Monitoring Plan (dated May 13, 2026), Emma Rott

Re: Conditional Approval Letter for Diggings East 100% Remedial Design Package Submittal (dated May 29, 2006), Emma Rott

Re: Conditional Approval Letter for Diggings East 95 % Remedial Design Package Submittal (dated March 25, 2006), the Silver Bow Creek Conservation Area (SBCCA) – 95 Percent Programmatic Technical Specifications Submittal (dated March 25, 2026), the Butte Priority Soils Operable Unit (BPSOU) SBCCA Operations and Maintenance (O&M) Plan (dated March 24, 2026), and the SBCCA Final Principles for a Greener Cleanup Report (dated February 4, 2026), Emma Rott

Re: Conditional Approval Letter for Draft Final 2026 Interim Site-Wide Groundwater Monitoring Quality Assurance Project Plan (dated May 6, 2026), Emma Rott

Re: Conditional Approval Letter for Draft Final Silver Bow Creek Conservation Area Materials Management Plan Revision 1 (dated March 24, 2026), Emma Rott

Re: Conditional Approval Letter for Final Silver Bow Creek Conservation Area (SBCCA) Construction Quality Assurance Plan and Draft Final Silver Bow Creek Conservation Area (SBCCA) Construction Monitoring Quality Assurance Project Plan (dated April 7, 2026), Emma Rott

Re: Conditional Approval Letter for Revised Clark Tailings Consolidated Waste Management Area (CTCWMA) Site Investigation Data Summary Report 2024 and Response to EPA Comment Letter (dated February 24, 2026), Emma Rott

Re: Conditional Approval letter for the Butte Priority Soils Operable Unit (BPSOU) Butte Treatment Lagoons (BTL) Groundwater Treatment System Quarterly Operation and Maintenance Report – Quarter 3 2025 (dated December 23, 2025), Emma Rott

Re: Conditional approval Letter for the Butte Priority Soils Operable Unit (BPSOU) Clark Tailings Consolidated Waste Management Area (CTCWMA) Site Investigation Quality Assurance Project Plan (QAPP) (dated April 16, 2026), Emma Rott

Re: Conditional approval Letter for the Butte Priority Soils Operable Unit (BPSOU) Clark Tailings Consolidated Waste Management Area (CTCWMA) Site Investigation Quality Assurance Project Plan (QAPP) (dated June 1, 2026), Emma Rott

Re: Conditional approval letter for the Butte Priority Soils Operable Unit (BPSOU) Silver Bow Creek Conservation Area (SBCCA) Operations and Maintenance (O&M) Plan (dated May 29, 2006), Emma Rott

Re: Conditional approval letter for the Butte Priority Soils Operable Unit Unreclaimed Sites Quality Assurance Project Plan, Emma Rott

Re: Conditional approval letter for the Butte Priority Soils Operable Unit Unreclaimed Sites Quality Assurance Project Plan, Emma Rott

Re: Conditional approval letter for the Draft Final Butte Mine Waste Repository Operations and Maintenance (O&M) Plan (dated August 3, 2026), Emma Rott

Re: Conditional Approval Letter for the Draft Final Butte Reduction Works (BRW) Smelter Area Mine Waste Remediation and Contaminated Groundwater Hydraulic Control Site Pre-Design Investigation (PDI) Evaluation Report (dated September 12, 2025), Emma Rott

Re: Conditional approval Letter for the Final Revised Silver Bow Creek Conservation Area (SBCCA) Construction Quality Assurance Plan (CQAP) (dated May 28, 2026) and the Final Silver Bow Creek Conservation Area (SBCCA) Construction Monitoring Quality Assurance Project Plan (QAPP) (dated May 28, 2026), Emma Rott

Re: Conditional approval letter for the Final Silver Bow Creek Conservation Area Materials Management Plan (dated May 28, 2026), Emma Rott

Re: Conditional Approval Letter with comments for Butte Priority Soils Operable Unit (BPSOU) Draft Final 2026 Interim Site-Wide Surface Water Monitoring Quality Assurance Project Plan (QAPP) (dated February 4, 2026), Emma Rott

Clark Tailings Consolidated Waste Management Area Site Investigation Quality Assurance Project Plan (QAPP), Woodard & Curran